bearing design

Articles About bearing design


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Webinar: Advanced Mainshaft Bearing Solutions for Wind Turbines

Mainshaft bearings inside wind turbines are subjected to extremely harsh operating conditions that result in failure patterns which include surface-initiated fatigue, abrasive wear and uneven internal load distribution. This webinar will introduce you to the latest engineering advancements in spherical roller bearing design, including solutions that allow potentially damaging thrust to be safely transferred through the bearing to the housing support. The resulting reduction in torque, friction and heat significantly improves the overall efficiency of the system, thereby enabling the wind turbine to generate more power - more reliably! Webinar Courtesy of Schaeffler
www.powertransmission.com/sc/schaeffler-wind-turbine-bearings/

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1 Improved Fuel and Energy Efficiency Through Optimized Bearing Design and Selection (February 2008)

Today, better fuel economy is a main objective in the automotive development process. It remains top-of-mind with the auto industry and consumers because of costs and environmental impacts. Because the industry’s average fuel-economy standard is required to increase by 40 percent by 2020, manufacturers and engineers are working to develop fuel-efficient, environmentally friendly and reliable designs for vehicles.

2 Rolling-Element Bearing Analysis (June 2013)

This article describes how more sophisticated modeling techniques allow the latest software to identify design issues with bearings, shafts, gears and complicated multi-body systems.

3 Bearing Repair Provides Valuable Alternative To Bearing Replacement for Heavy Industries (August 2008)

When a bearing is damaged, it is often removed from service and replaced before it reaches its full, useful and economical life. Advancements in bearing design, materials, bearing maintenance and repair methods have greatly improved the potential for and popularity of bearing repair as an effective way to extend the life of the bearing.

4 Software Bits (August 2017)

The latest updates in software for bearing design.

5 Gearbox Bearing Service Life: A Matter of Mastering Many Design Parameters (April 2012)

The availability of high-strength shaft materials, in combination with bearings with high carrying capacity, allows use of slimmer shafts. However, the modulus of elasticity remains the same, so seat design for bearings and gears must be given close attention.

6 Linear Bearing CAD Models and More On the Fly (April 2018)

Here's what one supplier is doing to take advantage of the mobile phone in your pocket.

7 Thrust Cone Bearings Provide Increased Efficiency for Helical Gear Units at Moderate Speed Levels (June 2018)

Thrust cone bearings are an elegant option to handle the axial forces generated by the torque transmission in helical-toothed gear stages. They have proven as an efficient and reliable bearing concept for integrally geared compressors but are nearly unknown in other fields of gearbox engineering. The presented investigations consider three aspects which appear relevant to extend the field of possible applications for thrust cones towards gearboxes constructed with roller bearings.

8 Desktop Engineering - How to Calculate Dynamic and Static Load Ratings (February 2015)

When comparing bearing suppliers, engineers are often left with few options other than to compare dynamic load ratings and corresponding life calculations. Of course, we can look at steel and manufacturing quality; but if we are comparing sources of similar quality, those items may not provide a large contrast. It often surprises people to learn that bearing capacities are calculated values, not tested values. Lately, however, a trend is emerging for bearing suppliers to increase their ratings for higher performance bearings that have premium features such as higher quality steel and specilaized heat treatment. Bearing companies are under intense competitive pressure to make every feature add to the dynamic capacity of their bearings because it is very well understood that an increase in capacity adds to the bottom line.

9 The Modified Life Rating of Rolling Bearings: A Criterion for Gearbox Design and Reliability Optimization (March 2015)

Engineers typically learn that the bearing L10 life can be estimated using the so called “C/P method” — or the “basic rating life” of the bearing, a method rooted in the 1940s. Major developments have since led to the “modified rating life,” released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that — despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor — use of these improved calculation methods are not practiced by all engineers. Indeed — many continue referring to the old model as a way of seeking compliance with existing, established practices.

10 Rolling Bearing Steels - A Technical and Historical Perspective - Part 1 (February 2013)

This paper summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability.

11 Four-Point Bearings Do Triple Duty While Saving Space (March 2015)

A four-point contact ball bearing makes it easy to simplify machine designs that combine radial, thrust and moment loads, because it can handle all three simultaneously. They are primarily used for slow-to-moderate-speed applications, or where oscillatory movement is predominant.

12 Minimum Design Speed Considerations for Sleevoil Bearings for Industrial Fan Applications (September 2016)

Slow speed operation of fan systems within the air handling industry is generally performed due to two reasons: a coast down operation is required for hot (induced draft) fans to cool down before shutdown (often by using a turning gear), and operational efficiency improvements can be achieved during non-peak periods by slow speed operation using a VFD. In either case, when these fans are supported by hydrodynamic bearings, it is the oil film thickness developed from the bearing-shaft interaction that limits the minimum speed that can be maintained without causing premature wear and bearing failure. This paper will present a brief overview of lubrication theory and critical design parameters to achieve slow speed operation.

13 Buyer Beware (April 2018)

No one likes paying too much for anything. Everyone wants to get a better deal. That's why you shop around before buying a new car. That's why you look at sale advertisements before buying a new refrigerator or big screen tv. The bigger the purchase, the more you want to compare prices.

14 Machine Parts No Longer in Production (June 2018)

Good machinery can last a lifetime. But, replacement parts for older equipment may be near impossible to find. So, what do you do when you're looking to replace hard-to-find bearings and related parts for older machines?

15 Bogus Bearings Still on a Roll (April 2018)

Counterfeits continue to vex big-name suppliers

16 Prediction of Heat Generation in Transmission Bearings by Application of FEM (September 2018)

Heat generation in bearings is manifested by the power losses of the transmission. Because of the rise in temperature due to heat generation, the appearance of dilatation adversely affects the bearings' geometrical characteristics.

17 Engineering Showcase - April 2019 (April 2019)

Special advertising section with a focus on bearings.

18 Motor System Reliability Considerations for Cost-Effective Purchasing Decisions (June 2008)

OEMs can minimize the cost of ownership by using highly efficient motors and recognizing when unreliable motors are driving up the operating costs of their applications.

19 Designing for Static and Dynamic Loading of a Gear Reducer Housing with FEA (February 2010)

A recent trend has been a movement to more user-friendly products in the mechanical power transmission industry. A good example of such a product is a high-horsepower, right angle, shaft-mounted drive designed to minimize installation efforts. Commonly referred to as an alignment-free type, it allows the drive package mounting to be quicker, more cost effective and require less expertise during installation. This facilitates the use of the drive in applications such as underground mining, where there is little room to maneuver parts. The most common application for the alignment-free style drive is for powering bulk material handling belt conveyors.

20 Development of an Educational Engineering Workshop on Electric Vehicle and Motor Technology (June 2010)

This paper describes the development of an educational program centered on electric motor and electric vehicle technology at the MIT (Massachusetts Institute of Technology) Edgerton Center.

21 Book Review: Design of Permanent-Magnet Brushless Machines (October 2010)

The latest offering by machine design experts J.R. Hendershot and T.J.E. Miller is an 822-page brushless permanent-magnet (PM) machine design book that serves as a worthy follow-up to their 1994 work.

22 Pros and Cons of Different Bearing Lubrication Methods (June 2019)

For a maintenance crew, it is important to know which bearings need re-lubrication and make sure they are lubricating those bearings. The bearings can be lubricated manually or by automatic lubrication systems. This article will review each method and discover its pros and cons.

23 A New Test Rig to Study Rolling Element Bearing Thermomechanical Behavior (April 2019)

Rolling element bearings are widely used in mechanical transmission to reduce friction between two rotating parts. With the further development of the electrical motor in mechanical industry, REBs operate more and more at high rotational speed. For these applications, REBs power losses can be predominant in mechanical transmissions.

24 How to Deal With Growing Pains (December 2018)

Wind turbines are getting bigger than ever, and the manufacturing infrastructure that facilitates their construction needs to start growing with them.

25 Automotive Adjustment (April 2019)

The automotive industry is shifting for everyone, bearings manufacturers included. Here's what you need to know to make sure you're shifting with it.

26 Progress in Rolling Bearing Technology for Refrigerant Compressors (December 2017)

Various surface treatment and bearing technology solutions are explored to solve challenging lubrication regimes.

27 Experimental Determination of Oil Rheology Parameters to be Implemented in Power Loss Predictions of Gears and Rolling Element Bearings (April 2019)

Rheology models express the way tribological conditions translate to shear stress of the lubricant and friction force on the interacting surfaces. Due to the complexity of the lubricant rheology, the friction coefficient is usually obtained experimentally either under the same operating conditions or by curve fitting in a properly chosen friction map. The current study aims at determining the rheological parameters of a lubricant based on friction measurements carried out on a commercial, readily available ball-on-disc machine.

28 Industry News (October 2018)

The complete Industry News section from the October 2018 issue of Power Transmission Engineering.

29 Guide to Proper Bearing Lubricating Practices (October 2017)

Understanding proper bearing lubrication procedures is critical to ensuring long-term, trouble-free performance. Klüber Lubrication has prepared this explanation as a general guide.

30 In Transit (December 2016)

The average travel time to work in the United States is 25.4 minutes, according to the U.S. Census Bureau. This number is probably low if you factor in a traffic accident in New York City, light rain in Chicago or it's simply Tuesday in Los Angeles. It's safe to say 25.4 turns into 45 minutes in many areas of the country at seven o'clock in the morning.

31 Bearing Lubricant Solution (December 2016)

A Chicago-area bakery was replacing the tray support bearings in its ovens on a reactionary basis. Their weekly inspection cycle was resulting in two mechanics spending an average of 20 labor hours per week to replace failed bearings. The premature bearing failures were caused by a combination of the high heat and humidity in the ovens, resulting in lubrication failure and contamination. When BDI was asked to recommend a solution, the bakery was averaging one month of bearing life in this application.

32 Eight Reasons to Use Air Bearings Over Mechanical Bearings (December 2016)

Mechanical guiding systems, such as crossedroller bearings, work well for most motion control applications; however, when precision, angular repeatability, and geometric performance (runout, straightness) are critical or where submicron bearing rumble is problematic, air bearings are recommended. An air-bearing stage is a rotary or linear positioner that floats on a cushion of air, using one of several preload mechanisms, nearly eliminating mechanical contact and thus wear, friction, and hysteresis effects. Here are eight reasons why an air-bearing stage might be the right choice for your application:

33 Bearing the Brunt of Earthquakes (December 2016)

America suffers $4.4 billion in losses due to earthquakes every year. While that's a drop in the bucket for our $16 trillion plus GDP, it's still a substantial amount of money, and some people are working to lessen those losses. One group is Earthquake Protection Systems (EPS), a company that is designing bearings to better protect buildings from earthquake damage.

34 Industry news (October 2016)

Latest News from around the industry.

35 ISO 281:2007 - Caveat Emptor (October 2016)

I was invited by Tom Astrene of TLT to write a response to the July 2010 TLT article (Ref. 1). My rebuttal — “In Search of a Fatigue Limit: A Critique of ISO Standard 281:2007” — was published in Tribology and Lubrication Engineering, TLT, August 2010 edition (Ref. 10). While this article is also available online, I will attempt to summarize the essence of my response.

36 A Model for Rolling Bearing Life with Surface and Subsurface Survival - Tribological Effects (September 2016)

Until now the estimation of rolling bearing life has been based on engineering models that consider an equivalent stress, originated beneath the contact surface, that is applied to the stressed volume of the rolling contact. Through the years, fatigue surface–originated failures, resulting from reduced lubrication or contamination, have been incorporated into the estimation of the bearing life by applying a penalty to the overall equivalent stress of the rolling contact. Due to this simplification, the accounting of some specific failure modes originated directly at the surface of the rolling contact can be challenging. In the present article, this issue is addressed by developing a general approach for rolling contact life in which the surfaceoriginated damage is explicitly formulated into the basic fatigue equations of the rolling contact. This is achieved by introducing a function to describe surface-originated failures and coupling it with the traditional, subsurface-originated fatigue risk of the rolling contact. The article presents the fundamental theory of the new model and its general behavior. The ability of the present general method to provide an account for the surface–subsurface competing fatigue mechanisms taking place in rolling bearings is discussed with reference to endurance testing data.

37 Special Modifications (October 2016)

Eddy Swiben, branch manager at BDI Canada, explains how to problem solve on an automatic cutter for tissue rolls. “This is a very major paper tissue manufacturer that sells paper tissue rolls all over America.” They roll paper tissue just like newsprint paper mills do. When the product is finally done and dried, they need to roll it on a light carton core 20-ft. long.

38 Ceramic Bearings for Water Processing, Water Filtration and Liquid Handling Applications (October 2016)

Bearings are an essential component in the majority of mechanical designs and equipment. It is important to consider the most effective materials when designing industrial machinery, especially in applications where water or other liquids are present. Many materials will be unable to overcome the challenges associated with operating in a wet or corrosive environment.

39 Guidelines for Bearing Seals (October 2016)

Equipment downtime and reduced component life are a few of the consequences — and potential costs — of using the wrong seals on many types of industrial equipment including pump bearing frames, electric motors, fans, pillow blocks, gearboxes and more. However, if correctly specified and installed, seals provide effective barriers that both retain lubricants as well as protect against water, corrosion, debris and other contaminants.

40 Defining and Predicting Housing Strength for Mounted Bearings (February 2017)

Design engineers across industries rely on pillow block bearings for a variety of tough and unconventional applications. Having access to data that backs housing strength performance claims is an integral part of choosing the right bearing to keep operations running optimally. What design considerations must be made when the application demands a pillow block installation on a non-horizontal orientation? What happens when bearing load is not applied through the base of the unit? Timken answers these questions with physical testing, advanced modeling and real-world experience to facilitate the selection of pillow block bearings for specific applications.

41 A Major Step Forward in Life Modeling (March 2017)

The SKF Generalized Bearing Life Model is (GBLM) an innovative new bearing rating life model that is designed to help engineers calculate bearing rating life in a more realistic manner. The new model is a major step forward for the industry and will play an important role in enabling OEMs and end users to better match bearings and applications, resulting in improved machine life and reduced operating costs.

42 Rolling Bearing Service Life Based on Probable Cause for Removal - A Tutorial (August 2017)

A bearing service life prediction methodology and tutorial indexed to eight probable causes for bearing failure and removal are presented - including fatigue. Bearing life is probabilistic and not deterministic. Bearing manufacturers' catalogue (L10) bearing life is based on rolling-element fatigue failure, at which time 90% of a population of bearings can be reasonably expected to survive, and 10% to fail by fatigue. However, approximately 95% of all bearings are removed for cause before reaching their L10 life. A bearing failure can be defined as when the bearing is no longer fit for its intended purpose. For a single bearing, you can only predict the probability of a failure occurring at a designated time - but not the actual time to failure.

43 Product News (September 2017)

The complete Product News section from the September 2017 issue of Power Transmission Engineering.

44 A Present State and Future Vision of Motor Drive Technology (December 2010)

One of the driving forces behind the industrial revolution was the invention—more than a century ago—of the electric motor. Its widespread use for all kinds of mechanical motion has made life simpler and has ultimately aided the advancement of humankind. And the advent of the inverter that facilitated speed and torque control of AC motors has propelled the use of electric motors to new realms that were inconceivable just a mere 30 years ago. Advances in power semiconductors—along with digital controls—have enabled realization of motor drives that are robust and can control position and speed to a high degree of precision. The use of AC motor drives has also resulted in energy savings and improved system efficiency. This paper reviews the development and application of inverter technology to AC motor drives and presents a vision for motor drive technology.

45 The Long and Short of It (October 2017)

10,000 Year Clock Needs Bearings that Run for 350 Million Cycles.

46 Getting to Know Your Bearing (August 2017)

Software Design, Analysis and Calculation Tools Help Solve Today's Engineering Challenges

47 Performance Testing of Composite Bearing Materials for Large Hydraulic Cylinders (April 2017)

Large hydraulic cylinders (LHCs) are integral components in the functioning of large machines in mechanically demanding, corrosive and abrasive environments, such as offshore drilling rigs. The materials utilized in these largescale hydraulic systems must deliver reliable performance throughout their expected lifecycle.

48 Bearing Good News (April 2017)

This issue's focus on bearings includes a number of important and informative articles about one of the most key components in any machine design.

49 Product News (April 2017)

Clutches and Brakes take center stage in the April 2017 edition of Product News.

50 Meet Norm Parker - Bearings Blogger (April 2017)

In case you missed them, following are three recent blog postings by our popular PTE bearings blogger - Norm Parker. We also felt that, should you not be a blog follower, this would be a good way to introduce you to Norm's bearings wisdom. Parker is currently the global senior specialist/roller bearings at Fiat Chrysler Automobiles (FCA).

51 The Hidden Cost of Incomplete Hydrodynamic Bearing Maintenance (April 2017)

Reliability and maintenance engineers can improve uptime and save money on both long-term maintenance and downtime costs by properly diagnosing and correcting bearing vibration issues when they exceed their acceptable limits. This requires inspecting the housing as well as the liner for wear, and replacing them as a pair when the housing is worn, so that wear-in between the mating surfaces can occur.

52 CNC System Upgrades (December 2017)

Automated production of large objects such as auto body prototypes, boat hulls and surfboards traditionally requires computerized numerical control (CNC) systems costing nearly a million dollars. Thomson Cuts Costs and Production Time for Autoscale Inc.

53 Achieving High Electric Motor Efficiency (April 2012)

The use of motor structures which can concentrate magnetic flux allows ferrite PM motors to achieve performance and power densities that approach those of PM motors using rare earth magnets, but without the cost penalties and supply source concerns of rare earth magnets.

54 Rating of Asymmetric Tooth Gears (April 2016)

Asymmetric tooth gears and their rating are not described by existing gear design standards. Presented is a rating approach for asymmetric tooth gears by their bending and contact stress levels, in comparison with symmetric tooth gears, whose rating are defined by standards. This approach applies finite element analysis (FEA) for bending stress definition and the Hertzian equation for contact stress definition. It defines equivalency factors for practical asymmetric tooth gear design and rating. This paper illustrates the rating of asymmetric tooth gears with numerical examples.

55 Can You Develop Your Own Custom Motor-and-Motion System (June 2016)

In this century’s complex, ever- changing world of manufacturing, such capabilities as hardware and software expertise, effective location and distribution, business savvy and yes, even luck, are some of the cardinal requirements for running a successful business.

56 Determining Diametral Pitch, Center Distance (October 2016)

I need help determining the diametral pitch needed to achieve the closest center-to-center distance for 2 spur gears. The 1st gear is a 34-tooth and the 2nd gear is a 28-tooth. The center-to-center distance between the gears needs to be as close to 2 1/8" as possible.

57 ISO-AGMA Standards: Specific Sliding Defined (March 2017)

Does the definition of specific sliding mean the same between ISO 21771:2007 and AGMA 917-B97? In ISO, specific sliding is the ratio of the sliding speed to the speed of a transverse profile in the direction of the tangent to the profile. In AGMA, specific sliding is ratio of gear tooth sliding velocity to its rolling velocity.

58 Industry News (March 2016)

News from around the industry

59 Gear Design Effects on Performance of High-Speed Helical Geartrains as Used in Aerospace Drive Systems (March 2016)

The performance of high-speed helical geartrains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High-Speed Helical Geartrain Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double-helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160–250° F) and lubricating jet pressure (60–80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling-off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears.

60 A New Geometrically Adaptive Approach for Tooth Contact Analysis of Gear Drives (August 2015)

Tooth contact analysis (TCA) is an important tool directed to the determination of contact patterns, contact paths, and transmission errors in gear drives. In this work, a new general approach that is applicable to any kind of gear geometry is proposed.

61 Effects of Contact Ratios on Mesh Stiffness of Helical Gears for Lower Noise Design (August 2015)

In this paper, the influences of various gear parameters on the mesh stiffness are systematically investigated by using the finite element method. The comprehensive analysis shows that contact ratios are the key factors affecting the fluctuation value of mesh stiffness.

62 Mutiple Gearset-Type Calculation Software (September 2015)

Is there a gear software package out there that will calculate the design of spur, helical, worm, and planetary gearsets? Also, we would like a program that calculates stresses and material selection. Finally, we would like to have the program calculate bearings loads, too. Thank you for your help.

63 Homogeneous Geometry Calculation of Arbitrary Tooth Shapes: Mathematical Approach and Practical Applications (February 2016)

This paper provides a mathematical framework and its implementation for calculating the tooth geometry of arbitrary gear types, based on the basic law of gear kinematics. The rack or gear geometry can be generated in two different ways: by calculating the conjugate geometry and the line of contact of a gear to the given geometric shape of a known geometry (e.g., a cutting hob), or by prescribing the surface of action of two gears in contact and calculating the correspondent flank shapes.

64 Determination of Load Distributions on Double Helical-Geared Planetary Gearboxes (June 2017)

Standardized calculation methods such as ISO 6336 and DIN 3990 already exist to determine the load distributions on gears inside a planetary gearbox, but by their very universal nature, these methods offer varying results depending on the gearbox design. Double helical gears, in particular, can benefit from more specific, complex algorithms to reach a maximum level of efficiency. Double helical gears interact with the rest of the gearbox differently than helical or spur gears, and thus benefit from different analytical models outside the standardized methods. The present research project describes the algorithm to determine the load distribution of planetary gearboxes with double helical gears.

65 Gear Span Measurements (August 2017)

A reader is looking for the best reference materials with formulas for gear measurements over pins.

66 Design Investigations and Indications for Acoustical Optimized Gear Meshes Using Plastic Gears (February 2019)

When it comes to a steel-gear mesh, there are several common standards and design rules on how to reduce noise emissions in the mesh. But if plastic gears are involved, this is no longer the case. The topic of this presentation is to highlight some of the differences between metal-and-plastic gear meshes, i.e. which design strategies can be stated as valid for metal as well as plastic and which are not?

67 Efficient Layout Process of Cylindrical Gears with Manufacturing Constraints (March 2019)

Cylindrical gear design can be divided into three steps. In the first step, rough gear pair dimensions such as center distance and face width are being estimated. Center distance and face width are directly linked to the available space (housing dimensions) and influence the overall size, weight and cost of the gears.

68 Optimization of Power Density by Local Gear Failure Modeling (March 2019)

Power density is a key factor in gear design. Increasing the power density enables engineers to use smaller gears for their applications which lead to smaller and lighter gear boxes. The benefit for example for the automotive industry is less moving load in the vehicles and therefor a reduction of fuel consumption and subsequently a reduction of CO2 emission. The limiting factor for the increase in power density of gears is the material strength in regard to the critical failure mode.

69 Motor Design for Aerospace Applications (June 2019)

Modern aircraft, missiles and space vehicles employ a large number of electric motors and actuators. While the basic design of these motors is in many respects very similar to that of their automotive and industrial counterparts, motors for aerospace applications differ significantly in some areas.

70 Product News (October 2018)

The complete Product News section from the October 2018 issue of Power Transmission Engineering.

71 Holistic Simulation of Gearboxes - System Simulation (August 2018)

Gearboxes are important assemblies within mechatronic systems. During the design phase of such systems it is essential to know the gearbox behavior under consideration of dynamic interactions with its environment. Holistic system simulation helps the engineer to understand this and to improve, adjust, or optimize gearboxes and their application.

72 Gear Design (December 2017)

Our expert explores standard vs. optimized gears, as well as high contact ratio gearing.

73 The Gizmo Society (June 2018)

It is hard these days to find any device that is not IoT-compatible or WiFi-connected. I recently had a new well pump installed that requires an iPhone for setup, which makes it hard for me to check or change the setup since I do not own an iPhone. In Olden Times, you had potentiometers or RS-232 connections - and that was fine.

74 Finite Element Method Based Analysis of Planetary Gear Systems Considering Backlash and Manufacturing Deviations (June 2018)

The load carrying capacity of gear transmissions depends strongly on design, material and operation conditions. Modern analysis methods, e.g. finite element analysis (FEA), consider the above parameters with more or less sufficient accuracy. Yet it remains an ongoing challenge to account for backlash and manufacturing errors, despite a definite need to do so.

75 Industry News (June 2018)

The complete Industry News section from the June 2018 issue of Power Transmission Engineering.

76 Transmissions in Transition (June 2015)

Experts gathered at the 9th CTI Symposium to discuss the challenges of reducing noise, improving energy efficiency and meeting the changing demands of the marketplace

77 High Contact Ratio Gearing: A Technology Ready for Implementation (April 2015)

Today’s competitive industrial gear marketplace demands products with excellent reliability, high capacity and low noise. Surface-hardened, ground tooth gearing predominates, but the legacy tooth forms handicap further improvements in capacity and noise generation. Vehicle and aircraft equipment use tooth forms not found in the standard tables to achieve better performance — with little or no increase in cost. This paper will propose adopting these high-contact ratio forms to industrial use.

78 Ball Screws Revisited - Ask the Expert (February 2013)

A reader asks for clarification on last issue's Ask the Expert column about ball screw sizing.

79 Considering Energy-Efficient Motors: Don't Forget the Gearbox (February 2013)

The mechanical components of your drive system play a major role in overall system efficiency. Don't cut corners.

80 Crowning Spur Teeth - Ask the Expert - December 2013 PTE (December 2013)

When designing spur teeth, is there a formula/guideline/design guide for determining the amount of crowning?

81 Gear Design Software, Engineer Beware (February 2014)

When software goes bad, what do we call it? System failure? Human failure? A virus? A number of words will work. How about this? Glitch. It has that onomatopoeic quality that fairly screams, Downtime! And with good reason -- software-generated miscalculations can have very expensive -- if not perilous -- repercussions.

82 Gear Design Software (February 2013)

When it comes to gear design software, the learning curve never ends. The leading vendors offer various training programs to keep their users well-informed.

83 High-Frequency, GaN Diode-Free Motor Drive Inverter with Pure Sine Wave Output (October 2012)

This article presents the first kW-Class, 3-phase GaN-based inverter. Hard-switched at 100-kHz PWM, its heart is a 6-in-1 power module with 600-V GaN power HEMTs, achieving a new efficiency of 98.5%, a more than 2% improvement.

84 Opportunities Amidst Crises (February 2011)

Energy-challenged industries--and countries--can benefit from improved motor design and materials.

85 Guidelines for Designing Better Motion Control Systems (February 2012)

Motion control systems engineers work chiefly in two well-defined areas: 1) new designs and 2) redesigns or retrofits. This article examines the best approach for each option.

86 The Things that Move Us (October 2012)

You may have noticed that the magazine looks different this issue. The new look is part of an overall effort to refine our focus. We wanted to make clear to potential subscribers and advertisers how this magazine is different, why its content is important and where it fits in the marketplace.

87 Selecting and Sizing Ball Screw Drives (October 2012)

The ball screw drive is an assembly that converts rotary motion to linear motion and vice versa. The ball screw drive consists of a ball screw and a ball nut with recirculating ball bearings...

88 Specifying a Gear - Ask the Expert (February 2014)

A reader asks what are the required parameters to properly specify a gear.

89 Working in AutoCAD (April 2014)

How does one draw and mesh involute gear teeth in AutoCAD?

90 The Small Motor Rule, How Will This Affect You (December 2014)

According to the Department of Energy (DOE), more than half of all electrical energy consumed in the U.S. is used by electric motors. To address this, several years ago, the DOE conducted a technical study as to what could be done to raise the efficiency levels of “small” motors. After years of study and litigation, the Small Motor Rule (SMR) was passed that covers two-digit NEMA frame single- and three-phase ¼ through 3 horsepower motors in open enclosures.

91 Engineering Showcase 2015 (March 2015)

One of our goals at Power Transmission Engineering is to help you understand, identify and select the best technology for your mechanical power transmission or motion control applications. With every project, you have to decide which components to use, and which suppliers, based on functionality, quality and price. We aim to help you make those decisions informed by providing the latest information on current technology, especially when it comes to mechanical components.

92 Diametral Pitch Calculation (April 2015)

Circular pitch gives me the size of the teeth in my mind, but diametral pitch does not. What is the purpose of the diametral pitch concept? Does it merely avoid pi in calculation?

93 Mathematical Modeling for the Design of Spiroid, Helical, Spiral Bevel and Worm Gears (April 2015)

Spiroid and worm gears have superior advantages for hightorque and miniaturization applications. And for this reason they are particularly preferred in aerospace, robotic and medical applications. They are typically manufactured by hobbing technology, a process with a typical overall lead time of 4 to 14 weeks.

94 Calendar (October 2014)

The Calendar for events happening in the industry

95 High-Tech Motors Evolving from PM Muck (September 2014)

University lab's motor eliminates pricey rare-earth magnets.

96 Testing of Alternative Spiral Bevel and Hypoid Gear Theory (August 2014)

Following is a presentation of a gear design based upon a theoretically perfect gear technology, for which an overview is offered for consideration. What follows is a report on the design's testing and subsequent manufacture of a hypoid gear pair for a 1999 Ford Mustang.

97 Evolution of Worm Gear Standards and their Consequences on Load Capacity Calculation Approach (September 2014)

Beginning with a brief summary and update of the latest advances in the calculation methods for worm gears, the author then presents the detailed approach to worm gear geometry found in the revised ISO TR 10828. With that information, and by presenting examples, these new methods are explained, as are their possibilities for addressing the geometrical particularities of worm gears and their impact upon the behavior and load capacity of a gearset under working conditions based on ISO TR 14521 — Methods B and C. The author also highlights the new possibilities offered on that basis for the further evolution of load capacity calculation of a worm gearset based on load and contact pressure distribution.

98 Wind Turbine Field and Test Rig Testing as Part of the Design Process for Gearboxes (September 2014)

The growth of worldwide energy consumption and emerging industrial markets demands an increase of renewable energy shares. The price pressure coming from coal, oil, nuclear and natural gas energy - combined with enormous worldwide production capacities for components of wind turbines - make wind energy a highly competitive market. The testing and validation of gearboxes within the test rig and the turbine environment attract a strong focus to the needs of the industry. The following contribution sums up the typical process requirements and provides examples for successful system and component verifications based on field measurements.

99 Industry News (September 2014)

The complete Industry News section from the September 2014 issue of Power Transmission Engineering.

100 Development of an Actuator for Ambient to Cryo Application (December 2010)

During the qualification campaign of the NIRSpec (near-infrared spectrometer) instrument mechanism, the actuator could not achieve the expected lifetime that had been extended during the development phase. The initial design could not be adapted to the requested number of revolutions during that phase. Consequently the actuator needed to be modified so that the function of the mechanism would not be endangered or, by extension, the overall function of the NIRSpec instrument. The modification included a change of the overall actuator design—internal dimensions, tolerances, materials, lubrication and assembly process—while keeping the interface to the mechanism, mass and function.

101 Analyzing Wind Power (August 2016)

Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface, and rotation of the earth. Wind Turbines convert the kinetic energy in wind into mechanical power.

102 Industry News (February 2012)

The complete Industry News section from the February 2012 issue of Power Transmission Engineering.

103 University Improves Sustainability of HVAC Motors in Platinum LEED Building (April 2012)

A new preventive maintenance program at a leading New England Ivy League university demonstrates how the push for more sustainable "green" building management has led to a growing awareness of a chronic, widespread problem with HVAC motors—electrical bearing damage and failure.

104 The Quick Fix - Rexnord Solves Bearing Installation and Removal Challenges (June 2012)

At a Midwestern producer of tubular steel products, measures taken to counteract the effects of impact on a quench tank roll made it difficult to remove and replace the conventional pillow block bearings that support the roll’s shaft.

105 Zero Friction Solution (June 2012)

Air bearings provide a more-precise view of print head variations.

106 Application of Ceramics to NU-Type Cylindrical Roller Bearings for Machine Tool Main Spindles (December 2011)

Bearings used to support main spindles on machine tools must be capable of higher speed and greater rigidity. This is true in that any main spindle that turns together with a tool or work piece mounted onto it is one of the critical machine tool components that directly affects machining efficiency and accuracy of the machine tool; and, the bearings that support the main spindle are the most critical machine elements on the machine tool.

107 PT Extras (April 2013)

The latest power transmission videos, articles and updates from online.

108 Industry News (April 2011)

The complete Industry News section from the April 2011 issue of Power Transmission Engineering.

109 Product News (June 2011)

The complete Product News section from the June 2011 issue of Power Transmission Engineering.

110 Non-Metallic Bearings - An Alternative Worth Considering (June 2011)

This article takes a look at alternative-material, non-metal bearings, and it turns out the first bearings of that type - wood, in this case, were the norm - not an alternative.

111 Radial Play (Internal Clearance in Ball Bearings) (August 2011)

At first glance, ball bearings are relatively simple mechanisms. However, an analysis of their internal geometries reveals that they are quite complex. For example, the ball to raceway conformity, the radial play, and the number of balls all impact the ability of a ball bearing to support loads under a variety of conditions.

112 Rolling Bearings in High-Speed Passenger Traffic (June 2012)

Passenger transport today moves significantly faster than ever before, often operating on separate tracks especially designed for high-speed trains. Accordingly, high-speed rolling bearings are very important components in the bogies of trains today. Maximum train speeds currently reach 380 km/h (236 mph) in the latest high-speed applications - 80% higher than in the earlier days of high-speed traffic. This paper presents two application examples of modern, high-speed traffic, together with some typical bearing arrangements and housings. It provides insight regarding measures taken in the bearing industry to meet the requirements of contemporary, high-speed traffic, and it cites important standards and regulations applicable for - but not restricted to - European applications. To be precise, the focus here is on journal bearings; information on traction motor bearings, transmission bearings and housings is included, but described in less detail.

113 Industry News (June 2012)

The complete Industry News section from the June 2012 issue of Power Transmission Engineering.

114 Calculating Inner Race Diameter (December 2012)

In this Ask the Expert article, Hans Wendeberg from SKF discusses some of the things you need to know when calculating bearing diameters.

115 Cruising with Curiosity (December 2012)

Power Transmission Components from Forest City Gear, Kaydon Bearings and Maxon Motors help power NASA's Curiosity Mars Rover.

116 Grease Lubrication Mechanisms in Rolling Bearing Systems (October 2013)

Grease lubrication has clear advantages over oil lubrication: Grease does not leak easily; it has sealing properties; and it protects bearing surfaces from corrosion. Its disadvantages are grease-life limitations and a limited cooling ability. Moreover, in some applications there is a risk of grease starvation, which leads to reduced lubricating films. However, if the right grease, sealing system and/or lubrication system are chosen, then grease lubrication offers clear benefits. This article summarizes aspects of grease lubrication mechanisms in rolling bearings.

117 Napoleon Engineering Services: Rigged for Success (December 2013)

For design engineers and purchasing agents alike, bearings can sometimes be like family. Oh, you know - can't live with 'em, can’t live without 'em.

118 The Skating Life (October 2012)

SMB Bearing Offers Unique Solutions for NorthwoodsFB finger-size skateboards.

119 Have a Pump, Motor, Generator, Turbine, Compressor or Gearbox - There is a Bearing for That! (October 2012)

Waukesha Bearings is known internationally for its capabilities, technology, size and application experience in the rotating (turbo) equipment industry. Following is a brief selection guide intended to assist engineers, specifiers, integrators and others in choosing the right bearing—and bearing technology—for the application.

120 Sleeve Bearings or Tilting Pad Bearings - Ask the Expert (August 2012)

A reader asks whether sleeve bearings can take the place of more expensive tilting pad bearings in a high-speed compressor application.

121 Wear-Resistant Bearings (August 2012)

More than a decade of intensive research and development has resulted in two new technologies that, when used in combination, expand the performance of rolling element bearings well beyond previous limits.

122 Bearing Protection Needed if Inverter-Duty Motors Are to Live up to their Name (August 2012)

All major manufacturers of 3-phase AC induction motors offer "inverter-duty" or "inverter-ready” models, but while these motors have inverter-rated insulation to protect the windings, the bearings--their most vulnerable parts--are too often ignored.

123 Not All Thin-Section Bearings Are Created Equal (February 2011)

American Bearing Manufacturers Association (ABMA) Standard 9 and ISO 281 give equations for calculating the basic dynamic radial load rating for ball bearings. These equations are based on a number of assumptions, many of which are not valid for thin-section bearings. (Thin-section bearings are described in ABMA standard 26.2.) Nevertheless, many thin-section bearing catalogs report load ratings based on these equations. Kaydon has developed a new method for calculating the dynamic radial load rating for thin-section ball bearings. The new method uses the contact stress and the number of stress-cycles-per-revolution to calculate the capacity. The new numbers are based on five years of actual test results. These equations can also be used to calculate the dynamic radial load rating for four-point contact ball bearings, which are not covered in ABMA standard 9 or ISO 281.

124 Energy Efficiency by Using Innovative Bearing Solutions (August 2010)

Based on simulation methods and calculation tools developed by the Schaeffler Group and presented in the first part of this paper, three approaches regarding increased efficiency based on rolling bearings are presented.

125 Capacity--And the Lack of It--Rules (February 2008)

U.S. wind turbine growth puts a new spin on bearing manufacture.

126 Bearing Lubrication Under Extreme Conditions, Part II (February 2008)

Rolling element or sleeve bearings often are required to operate under extreme conditions. In these instances, it is more important than ever to follow proper lubrication selection and maintenance procedures to maximize effective life and efficient performance.

127 Industry News (February 2008)

The complete Industry News section from the February 2008 issue of Power Transmission Engineering

128 Saltwater Solutions from igus (April 2008)

igus bearings solve undersea issues for the marine vehicle industry.

129 Grip Tight Done Right (February 2008)

Baldor bearings make the grade with Sapphire Recovery and Twin City Fan.

130 Motion Drive and Automation at Hannover 2013 (April 2013)

Power Transmission and control companies will be on hand during Hannover Messe 2013 to display the latest technology offerings in key product categories including roller bearings, gear wheels, pumps, motors, transmissions, drive system components, clutches and braking systems.

131 Power Loss and Axial Load Carrying Capacity of Radial Cylindrical Roller Bearings (June 2013)

This paper is intended to enlarge the application range of radial cylindrical roller bearings by means of a more precise determination of thrust load capacity and more cost-effective design.

132 Bearing Associations Help Demystify Bearings Buys (June 2013)

The ABMA, BSA and PTDA help keep things rolling.

133 Boilermakers Announce Bearing Technology Breakthrough (June 2013)

Student research project at Purdue could revolutionize predictive bearing failure.

134 Rolling Bearing Steels - A Technical and Historical Perspective, Part 2 (April 2013)

This paper is part 2 of 2 in a series that summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability.

135 BSA is the Forum that Keeps Bearing Companies Rolling (December 2008)

In today’s increasingly competitive global economy, industries and the companies that serve them are always looking for an edge. Price and quality being routinely accepted as a given, businesses—large and small—are always looking for a little help. For the worldwide bearing industry, that help exists in the form of the Bearing Specialists of America (BSA).

136 High-Capacity Bearings Carry the Load for Chinese Gearbox Manufacturer (December 2008)

Th e signing of a contract for more than 5,000 sets of SKF’s latest high-capacity cylindrical roller bearings (HCCRB) for wind turbines will impart added load-carrying capacity, more reliability and longer life to the Nanjing Gear Company’s (NGC) line of gearboxes for wind generation applications.

137 Selecting the Right Precision Ball Material for Aggressive Environments (February 2010)

This article will examine the major materials used to enhance balls to resist aggressive environments and help in selecting the right one.

138 Bogus Bearings Beat Price and Lead Time, But at What Cost (April 2010)

When your $100 “Rolex” falls apart on your wrist, well, what did you expect? But when bogus bearings find their way into safety-sensitive applications, lives are at stake.

139 Linear Motion Q&A: Customized Machinery Built with Off-the-Shelf Components (April 2010)

This Q&A session with various experts at Thomson Linear Systems covers linear slides & stages, clutches & brakes, bearings and actuators.

140 A Recipe for Quality Big Bearings (June 2010)

Many power transmission components require a certain level of customization for each individual project. The big bearing market is no exception. Construction, mining, steel, marine and wind applications aren’t exactly areas where customers buy bearings in bulk.

141 The Best-Kept Secret in Green Technology (December 2009)

The Bearing Specialists Association explains the role of bearings in ensuring the efficient operation of machinery.

142 Improving Equipment Uptime - Composite Seals Meet the Challenge (October 2009)

In an industrial application, equipment uptime is vital for on-time performance and profitability. The rotating members of industrial machines are subject to the highest degree of wear and are more susceptible to failure than non-moving parts. Bearing surfaces are the most critical and often the most expensive portion of the rotary assembly; it is imperative to protect these components. The primary protector of these components is the industrial seal.

143 The Green Revolution - A Global Win-Win (February 2009)

Green technology is more than changing a couple of light bulbs or reducing waste. In 2009, the concept is relevant in every facet of manufacturing as companies make a greater push towards energy efficiency and sustainability. In the power transmission and motion control fields, this technology has been integrated into the daily routine, both as an environmentally friendly business venture and a way to offer green products to customers. It’s apparent that the revitalization of manufacturing, both here and abroad, will center on energy technology.

144 Smart Bearings are in Control--But Full Potential Remains Untapped (June 2009)

Bearings with integrated sensors are used in a wide variety of applications, but many potential industrial uses are not yet implemented.

145 Intermetallic Nickel-Titanium Alloys for Oil-Lubricated Bearing Applications (August 2009)

Nitinol 60 (60NiTi), an intermetallic nickel-titanium alloy containing 60 wt % nickel and 40 wt % titanium, is shown to be a promising material for oil-lubricated, rolling and sliding contact applications such as bearings and gears.

146 How To Use a Hand-Held Micrometer to Measure Miniature and Instrument Ball Bearings (December 2013)

For the most accurate measurements, miniature and instrument ball bearing dimensions should be measured with a calibrated air gauge. A good second option is a calibrated optical comparator. On occasion, it may be necessary to use a calibrated, hand-held micrometer to double-check a measurement or for simple verification while working in the field.

147 Should You Pay a Premium for a Mounted Ball Bearing (December 2013)

Mounted ball bearings are everywhere in industrial applications. They serve critical roles in keeping a manufacturing operation running smoothly and in ensuring that equipment functions properly and reliably. So why might it be advisable to spend significantly more for a dimensionally comparable bearing from one supplier versus another?

148 Industry News (February 2016)

Latest news from around the Industry

149 The SKF High-Capacity Cylindrical Roller Bearing (Spring 2007)

Th e ISO defi nition of a full- complement bearing states that the bearing does not have a cage. When that defi nition was written, it was not technically possible to have a full-complement bearing with a cage. But SKF’s new high-capacity cylindrical roller bearing combines the load-carrying capacity of a fullcomplement bearing with the benefi ts of a bearing with a cage (Fig.1).

150 Bearings for High Temperatures (Fall 2007)

When rolling element or sleeve bearings operate under extreme conditions, it’s more important than ever to follow proper lubrication selection and maintenance procedures to maximize eff ective life and effi cient performance.

151 Troubleshooting Through Reverse Engineering (March 2016)

Michael Odom, certified bearing specialist and customer sales and service at Applied Industrial Technologies, explains how he used his bearing expertise to save a customer both money and downtime.

152 Identifying Bearing Failure (February 2016)

Guy Gendron, certified bearing specialist and technical sales representative at Timken Canada L.P. explains how he used his bearing expertise to increase a customer’s productivity.

153 Counterfeit Consequences (February 2016)

Power Transmission Engineering is collaborating with the Bearing Specialists Association (BSA) on a special section within the magazine. Bearing Briefs will present updated reports on bearing topics for each issue in 2016. Complimentary access to all BSA Bearing and Industry Briefs is available on the BSA website at www.bsahome.org/tools. Additionally, our new Field Notes section on page 34 will feature field reports from BSA’s Certified Bearing Specialists.

154 Recalibrated Equations for Determining Effect of Oil Filtration on Rolling Bearing Life (September 2015)

In 1991, Needelman and Zaretsky presented a set of empirically derived equations for bearing fatigue life (adjustment) factors (LFs) as a function of oil filter ratings.

155 Beyond Bearings Basics (October 2015)

There are thousands of sizes and types of standard bearings. In many applications, specifying a standard bearing yields an effective result.

156 Preventing Roller Bearing Failure (December 2015)

I’m building a custom gearbox with 7075 T-6 spur gears, and I’m concerned that aluminum flakes will enter the races on the roller bearings (SKF 2307) and cause premature failure. So my question is — should I place an oil seal on the shaft first to protect the bearing — or is this an unfounded concern and I should mount the seal in the typical manner outside the bearing? Or both? Or go with a sealed bearing? I’m confused and could use your expertise, please.

157 Industry News (December 2015)

News from around the industry

158 Load Ratings & Bearing Life (March 2016)

Power Transmission Engineering is collaborating with the Bearing Specialists Association (BSA) on a special section within the magazine. Bearing Briefs will present updated reports on bearing topics for each issue in 2016. Complimentary access to all BSA Bearing and Industry Briefs is available on the BSA website at www.bsahome.org/tools.

159 He Shoots, He Scores! (April 2016)

There’s nothing quite as satisfying as scoring a goal. Here at Power Transmission Engineering, our goal is to provide you with as much relevant educational and technical material as possible, and every issue we strive to cover the subjects of power transmission and motion control from as many different angles as possible, so that no matter your job title, and no matter your industry, if gears, bearings, motors and related components are important to you, we’ve got you covered.

160 The Meaning of Life (August 2016)

End users and OEMs frequently specify "lubed-for-life" mounted bearings, thinking the lubed-for-life bearings will deliver the same life — without lubrication — as bearings that currently require periodic lubrication. The truth is it depends on many factors, and only a detailed review of the application and testing will provide a more accurate answer.

161 High-Temp Bearing Replacement (August 2016)

Richard (RJ) Seguin, CBS and technical sales representative at AMI Bearings, explains how his bearing expertise tripled the life of a customer’s bearings.

162 Opening the Envelope on Bearing Vibration (September 2016)

Experienced operators can often tell if a machine is not working properly, on the basis that it does not ‘sound right.’ The same principle can be applied — using modern electronics — to identify the exact cause of the problem. Sensitive accelerometers can detect and analyze the vibrations from industrial equipment, highlighting problems such as misalignment or bearing imbalance. The technique is known as vibration analysis. It can identify bearing failure in the very early stages, when there is a microscopic defect on the raceway, for example. The problem is that the identifying signal is usually drowned out in all the other noise emanating from the machine.

163 Proper Handling of Bearings (September 2016)

Rolling-element bearings are high-precision components that need to be stored and handled carefully to perform as designed. Proper storage and handling of a bearing before, during and after installation is important because once debris enters a bearing, it reduces the life.

164 Proper Bearing Installation (June 2016)

Gregory (Keith) Boutwell, CBS and executive account manager at B&D Technologies (a division of B&D Industrial), explains how he used his bearings expertise to save a customer thousands of dollars through correct bearing installation.

165 Analyzing the Poultry Process (June 2016)

Power Transmission Engineering is collaborating with the Bearing Specialists Association (BSA) on a special section within the magazine. Bearing Briefs will present updated reports on bearing topics for each issue in 2016. Complimentary access to all BSA Bearing and Industry Briefs is available on the BSA website at www.bsahome.org/tools.

166 Preventing Downtime for Hanger Bearings (April 2016)

Dale Renner, CBS and sales representative at Bearing Headquarters Co., explains how his bearing expertise helped solve a customer’s problem and saved significant downtime and cost.

167 What Lubrication Method Should I Use (April 2016)

in the performance and life of a rolling element bearing. Less than 10 percent of bearings reach their theoretical L10 life, and poor lubrication can be attributed to 80 percent of those that fall short. Ideally, a lubricant forms a film layer between moving components in a bearing, separating moving parts, minimizing friction and preventing wear between balls or rollers, raceways and retainers. Lubricants also protect metal surfaces from corrosion and moisture, dissipate heat and can even prevent the ingress of contaminants.

168 Analyzing the Cement Process (April 2016)

The manufacturing process begins in a limestone quarry. Mining methods such as ripping, dozing, drilling and blasting are commonly employed. Limestone provides the first essential component, calcium, for the anufacture of cement. Materials are transported to the crushing plant for further size reduction. Common methods of transport are trucks, loaders and belt conveyors.

169 Setting Techniques for Tapered Roller Bearings (September 2015)

Tapered roller bearings can be set at initial machine assembly to any desired axial or radial clearance. This unique feature enables a designer to control bearings to meet anticipated application operating conditions, and thereby provide optimum bearing and system performance.

170 Tales from the Bearings Blog (June 2015)

The following short articles first appeared on www.powertransmission.com. They are part of the ongoing series of hints, technical tidbits and inside knowledge presented by our resident blogger, Norm Parker. If you like what you see here and are interested in learning more, visit www.powertransmission.com/blog.

171 Lower Service Life Plus Less Waste Equals Lower Cost (April 2014)

Bearings that show wear may not always need to be replaced. Depending on the degree and type of wear, they may be candidates for reconditioning, a process that restores bearings to like-new specifications and performance - at an average 50 to 60 percent of the cost of replacement.

172 Gear Lubrication: Long-Term Protection for Wind Turbines (April 2014)

The chemical and physical properties of gear oils may change, depending - more or less - upon their formulation and the environmental conditions under which they are used. This is why - after three years of use in a wind turbine - a gear oil was examined to determine if indeed changes were evident and if the protection of the gears and rolling bearings still met the same requirements as would be expected of fresh oil. Our findings revealed that the existing gear oil - as well as its ability to protect the gears and rolling bearings - had degraded very little compared to fresh oil.

173 Adjusting Tapered Roller Bearings (June 2014)

What are the best methods to adjust tapered roller bearings?

174 Choosing the Right Grade - Specifying Stainless Bearing Steel (August 2014)

A reader asks: I've determined that a stainless steel bearing is the best option for my application. I'm being asked to specify the grade of stainless steel in my product design. I'm not sure which grade to select and specify. Can you help?

175 Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes (March 2014)

A critical problem for wind turbine gearboxes is failure of rolling element bearings where axial cracks form on the inner rings. This article presents field experience from operating wind turbines that compares the performance of through-hardened and carburized materials. It reveals that through-hardened bearings develop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. The field experience further shows that a carburized bearing with a core having low carbon content, high nickel content, greater compressive residual stresses, and a higher amount of retained austenite provides higher fracture resistance and makes carburized bearings more durable than through-hardened bearings in the wind turbine environment.

176 Study of Multiple-Point Oil-Jet Lubrication of High-Speed Ball Bearings (June 2014)

The air-oil, two-phase flow inside the multiple-point, oil-jet lubrication ball bearing was studied based on CFD (computational fluid dynamics) theory and technique, and compared with single-point, oil-jet lubrication. The results indicate that the air-oil distribution inside the bearing with multiple-point, oil-jet lubrication is more uniform than single-point injection.

177 All for One, One for All (February 2014)

Collaboration moves bearing modeling and simulation software forward

178 Fluid Power Free-for-All (February 2014)

IFPE offers the right balance of technology and education.

179 Best Practices for Bearing Protection (June 2014)

For either brand-new motors or those already in service, "best practices" means that informed technicians can make use of the latest diagnostic techniques (vibration analysis, thermography, shaft-voltage testing, etc.) to prevent electrical bearing damage -- either at the very beginning or very quickly thereafter. If done correctly, the work need only be done once.

180 Tapered Roller Bearing Application Guide (June 2014)

This article summarizes some common hurdles, issues and questions encountered by the newer and casual users of tapered roller bearings.

181 Dude - Where's My Preload (August 2014)

Many of us have been there; the bearings had the correct preload. You know it, you were there, and you personally saw the measurements. Now, the testing is done and the preload is gone. Not a little gone, not sort of gone - gone, gone. Finger pointing ensues. Suppliers are dragged in by their wrinkly Polo collars. You know the drill. Losing preload in a tapered roller bearing (TRB) system over the life of your application can be a troublesome problem, particularly for gear sets that are prone to noise or severe applications that rely on a very rigid and stable system.

182 PT Extras (September 2014)

Videos, tweets, blog posts and other online exclusive from PTE and mechanical power transmission component suppliers.

183 Finite Element Evaluation of Bearing Instrumentation Method (December 2014)

This paper presents an evaluation of measurements being taken on a 750 kW wind turbine gearbox being tested by the National Renewable Energy Laboratory (NREL). High-speed stage gears and bearings have been identified as critical components of the gearbox; during gearbox testing, these components were instrumented and tests were developed to evaluate loads on high-speed tapered roller bearings (TRBs). In this paper an advanced finite element-based contact modeling procedure has been applied to model the high-speed stage with the bearings fully modeled in order to evaluate strain levels. A major conclusion is that the strains of the slotted grooves are at such a level that they have acceptable signal-to-noise levels. This was verified by the results of the initial experiments presented here.

184 Plastic Bearings Have Staying Power (April 2015)

During the past three decades there has been an evolution in the advancement and use of highly engineered plastics in bearing applications.

185 The True Cost of Bearing Lubrication (June 2015)

Machine and equipment manufacturers today are feeling more pressure than ever to reduce costs without sacrificing machine performance — a balancing act difficult to achieve. OEMs often overlook a simple solution that can have a positive, long-term impact on profitability for themselves and their customers, i.e. — the elimination of bearing lubricant.

186 The Path to Smarter Bearings (June 2015)

At Hannover Messe, Power Transmission Engineering had the opportunity to sit down with Stefan Hantke, president of the Industrial North America division of Schaeffler USA, to discuss the current stateof- the-art in bearings manufacturing, the trends in industrial bearings and the current state of U.S. manufacturing. (In the meantime Stefan Hantke has taken over responsibility for the global sales activities of Schaeffler Industrial)

187 Pre-Tension Thrust Bearings (December 2014)

What is the recommended method of gripping a spinning shaft (with up to 130 hp of rotational energy) to install pre-tension thrust bearings and conventional thrust bearings (load = hundreds of pounds) when the shaft cannot have any high points because it must pass through an area of tight clearances to assemble? Will snap rings still withstand the harsh vibration of this environment?

188 Made in China: A GM Engineer's First-Hand Perspective on the Chinese Roller Bearing Industry (October 2014)

Believe me when I tell you that — as a domestic automotive engineer — I bleed U.S. manufacturing. I have never lived more than 50 miles from Detroit,

189 TLC Still Needed for New Axles (September 2014)

A reader asks: I have heard that new axles no longer need a break-in period. True or false?

190 Bearing Basics (October 2014)

BEARINGS BASICS Q&A: IN CASE YOU DIDN’T KNOW…

191 Premature Bearing Failures in Wind Gearboxes and White Etching Cracks (October 2014)

Wind turbine gearboxes are subjected to a wide variety of operating conditions, some of which may push the bearings beyond their limits. Damage may be done to the bearings, resulting in a specific premature failure mode known as white etching cracks (WEC), sometimes called brittle, short-life, early, abnormal or white structured flaking (WSF). Measures to make the bearings more robust in these operating conditions are discussed in this article.

192 Cutting Downtime in Lumber Application (September 2016)

Ernest Head (Arnie), CBS and technical sales representative at Motion Canada helped save a lumber industry customer time and money by adapting a bearing solution for another client. Here’s how:

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