Articles About bearing design
(SPONSORED CONTENT)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
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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.
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.
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.
The latest updates in software for bearing design.
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.
Here's what one supplier is doing to take advantage of the mobile phone in your pocket.
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.
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.
Engineers typically learn that the bearing L10 life can be estimated using the so called âœC/P methodâ â” or the âœbasic rating lifeâ of the bearing, a method rooted in the 1940s. Major developments have since led to the âœmodified rating life,â 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 â” 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 â” use of these improved calculation methods are not practiced by all engineers. Indeed â” many continue referring to the old model as a way of seeking compliance with existing, established practices.
This paper summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability.
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.
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.
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.
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?
Counterfeits continue to vex big-name suppliers
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.
Special advertising section with a focus on bearings.
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.
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.
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.
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.
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.
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.
Wind turbines are getting bigger than ever, and the manufacturing infrastructure that facilitates their construction needs to start growing with them.
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.
Various surface treatment and bearing technology solutions are explored to solve challenging lubrication regimes.
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.
The complete Industry News section from the October 2018 issue of Power Transmission Engineering.
Understanding proper bearing lubrication procedures is critical to ensuring long-term, trouble-free performance. Klüber Lubrication has prepared this explanation as a general guide.
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.
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.
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:
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.
Latest News from around the industry.
I was invited by Tom Astrene of TLT to write a response to the July 2010 TLT article (Ref. 1). My rebuttal â” âœIn Search of a Fatigue Limit: A Critique of ISO Standard 281:2007â â” 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.
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 surfaceâ“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 surfaceâ“subsurface competing fatigue mechanisms taking place in rolling bearings is discussed with reference to endurance testing data.
Eddy Swiben, branch manager at BDI Canada, explains how to problem solve on an automatic cutter for tissue rolls. âœThis is a very major paper tissue manufacturer that sells paper tissue rolls all over America.â 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.
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.
Equipment downtime and reduced component life are a few of the consequences â” and potential costs â” 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.
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.
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.
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.
The complete Product News section from the September 2017 issue of Power Transmission Engineering.
One of the driving forces behind the industrial revolution was the inventionâ”more than a century agoâ”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 semiconductorsâ”along with digital controlsâ”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.
10,000 Year Clock Needs Bearings that Run for 350 Million Cycles.
Software Design, Analysis and Calculation Tools Help Solve Today's Engineering Challenges
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.
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.
Clutches and Brakes take center stage in the April 2017 edition of Product News.
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).
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.
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.
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.
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.
In this centuryâ™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.
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.
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.
News from around the industry
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 (160â“250° F) and lubricating jet pressure (60â“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.
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.
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.
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.
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.
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.
A reader is looking for the best reference materials with formulas for gear measurements over pins.
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?
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.
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.
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.
The complete Product News section from the October 2018 issue of Power Transmission Engineering.
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.
Our expert explores standard vs. optimized gears, as well as high contact ratio gearing.
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.
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.
The complete Industry News section from the June 2018 issue of Power Transmission Engineering.
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
Todayâ™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 â” with little or no increase in cost. This paper will propose adopting these high-contact ratio forms to industrial use.
A reader asks for clarification on last issue's Ask the Expert column about ball screw sizing.
The mechanical components of your drive system play a major role in overall system efficiency. Don't cut corners.
When designing spur teeth, is there a formula/guideline/design guide for determining the amount of crowning?
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.
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.
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.
Energy-challenged industries--and countries--can benefit from improved motor design and materials.
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.
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.
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...
A reader asks what are the required parameters to properly specify a gear.
How does one draw and mesh involute gear teeth in AutoCAD?
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 âœsmallâ 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.
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.
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?
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.
The Calendar for events happening in the industry
University lab's motor eliminates pricey rare-earth magnets.
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.
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 â” 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.
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.
The complete Industry News section from the September 2014 issue of Power Transmission Engineering.
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 designâ”internal dimensions, tolerances, materials, lubrication and assembly processâ”while keeping the interface to the mechanism, mass and function.
Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earthâ™s surface, and rotation of the earth. Wind Turbines convert the kinetic energy in wind into mechanical power.
The complete Industry News section from the February 2012 issue of Power Transmission Engineering.
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.
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 rollâ™s shaft.
Air bearings provide a more-precise view of print head variations.
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.
The latest power transmission videos, articles and updates from online.
The complete Industry News section from the April 2011 issue of Power Transmission Engineering.
The complete Product News section from the June 2011 issue of Power Transmission Engineering.
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.
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.
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.
The complete Industry News section from the June 2012 issue of Power Transmission Engineering.
In this Ask the Expert article, Hans Wendeberg from SKF discusses some of the things you need to know when calculating bearing diameters.
Power Transmission Components from Forest City Gear, Kaydon Bearings and Maxon Motors help power NASA's Curiosity Mars Rover.
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.
For design engineers and purchasing agents alike, bearings can sometimes be like family. Oh, you know - can't live with 'em, canâ™t live without 'em.
SMB Bearing Offers Unique Solutions for NorthwoodsFB finger-size skateboards.
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 bearingâ”and bearing technologyâ”for the application.
A reader asks whether sleeve bearings can take the place of more expensive tilting pad bearings in a high-speed compressor application.
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.
All major manufacturers of 3-phase AC induction motors offer "inverter-duty" or "inverter-readyâ models, but while these motors have inverter-rated insulation to protect the windings, the bearings--their most vulnerable parts--are too often ignored.
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.
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.
U.S. wind turbine growth puts a new spin on bearing manufacture.
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.
The complete Industry News section from the February 2008 issue of Power Transmission Engineering
igus bearings solve undersea issues for the marine vehicle industry.
Baldor bearings make the grade with Sapphire Recovery and Twin City Fan.
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.
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.
The ABMA, BSA and PTDA help keep things rolling.
Student research project at Purdue could revolutionize predictive bearing failure.
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.
In todayâ™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, businessesâ”large and smallâ”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).
Th e signing of a contract for more than 5,000 sets of SKFâ™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 Companyâ™s (NGC) line of gearboxes for wind generation applications.
This article will examine the major materials used to enhance balls to resist aggressive environments and help in selecting the right one.
When your $100 âœRolexâ 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.
This Q&A session with various experts at Thomson Linear Systems covers linear slides & stages, clutches & brakes, bearings and actuators.
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 arenâ™t exactly areas where customers buy bearings in bulk.
The Bearing Specialists Association explains the role of bearings in ensuring the efficient operation of machinery.
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.
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. Itâ™s apparent that the revitalization of manufacturing, both here and abroad, will center on energy technology.
Bearings with integrated sensors are used in a wide variety of applications, but many potential industrial uses are not yet implemented.
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.
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.
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?
Latest news from around the Industry
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 SKFâ™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).
When rolling element or sleeve bearings operate under extreme conditions, itâ™s more important than ever to follow proper lubrication selection and maintenance procedures to maximize eff ective life and effi cient performance.
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.
Guy Gendron, certified bearing specialist and technical sales representative at Timken Canada L.P. explains how he used his bearing expertise to increase a customerâ™s productivity.
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 BSAâ™s Certified Bearing Specialists.
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.
There are thousands of sizes and types of standard bearings. In many applications, specifying a standard bearing yields an effective result.
Iâ™m building a custom gearbox with 7075 T-6 spur gears, and Iâ™m concerned that aluminum flakes will enter the races on the roller bearings (SKF 2307) and cause premature failure. So my question is â” should I place an oil seal on the shaft first to protect the bearing â” 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? Iâ™m confused and could use your expertise, please.
News from around the industry
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.
Thereâ™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, weâ™ve got you covered.
End users and OEMs frequently specify "lubed-for-life" mounted bearings, thinking the lubed-for-life bearings will deliver the same life â” without lubrication â” 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.
Richard (RJ) Seguin, CBS and technical sales representative at AMI Bearings, explains how his bearing expertise tripled the life of a customerâ™s bearings.
Experienced operators can often tell if a machine is not working properly, on the basis that it does not â˜sound right.â™ The same principle can be applied â” using modern electronics â” 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.
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.
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.
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.
Dale Renner, CBS and sales representative at Bearing Headquarters Co., explains how his bearing expertise helped solve a customerâ™s problem and saved significant downtime and cost.
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.
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.
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.
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.
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.
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.
What are the best methods to adjust tapered roller bearings?
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?
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.
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.
Collaboration moves bearing modeling and simulation software forward
IFPE offers the right balance of technology and education.
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.
This article summarizes some common hurdles, issues and questions encountered by the newer and casual users of tapered roller bearings.
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.
Videos, tweets, blog posts and other online exclusive from PTE and mechanical power transmission component suppliers.
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.
During the past three decades there has been an evolution in the advancement and use of highly engineered plastics in bearing applications.
Machine and equipment manufacturers today are feeling more pressure than ever to reduce costs without sacrificing machine performance â” 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. â” the elimination of bearing lubricant.
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)
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?
Believe me when I tell you that â” as a domestic automotive engineer â” I bleed U.S. manufacturing. I have never lived more than 50 miles from Detroit,
A reader asks: I have heard that new axles no longer need a break-in period. True or false?
BEARINGS BASICS Q&A: IN CASE YOU DIDNâ™T KNOWâ¦
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.
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. Hereâ™s how:
News Items About bearing design
1 Nord Offers VL Heavy Duty Spread Bearing Designs (January 13, 2016)
Nord offers several variations of the VL heavy duty spread bearing designs, all which have specific features and advantages based on the ...
2 NSKs New Bearing Designs Deliver Longer Life, Higher Speeds in Papermaking Machines (March 2, 2007)
Rolling bearings used in the production of paper undergo a continuous production cycle, are required to handle high-temperature condition...