Articles About gearboxes
(SPONSORED CONTENT)Understanding Your Gear Drive Ratings
The power capacity of a gear drive is important to ensure successful operation of driven equipment with minimum downtime. Making sure that the unit is correct for the application can be a difficult task. Download our whitepaper to achieve a better understanding of your gear drive ratings. White Papers Courtesy of Rexnord
In many material-handling applications it is necessary to make adjustments in the load support center distances to accommodate loads of different lengths or widths, especially if these loads have to be captured to avoid shifting. These loads can come in variety of shapes and sizes, and encompass a variety of industries. White Papers Courtesy of DieQua
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In recent years the estimation of gearbox power loss is attracting more interest — especially in the wind turbine and automotive gearbox industry — but also in industrial gearboxes where heat dissipation is a consideration as well. As new transmissions concepts are being researched to meet both ecological and commercial demands, a quick and reliable estimation of overall efficiency becomes inevitable in designing the optimal gearbox.
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.
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 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.
In order to analyze the different gear oils suitable for the lubrication of wind turbine gearboxes, five fully formulated ISO VG 320 gear oils were selected. In between the selected gear oils, four PAO base oils can be found: PAOR, PAOM, PAOC and PAOX. A mineral-based oil (MINR) was also included as reference.
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.
Dave Soma, the mechanical supervisor at Leland Olds Station, a coal-fired power plant near Stanton, North Dakota, says he and his maintenance team care deeply about keeping the plant running and providing people electricity, especially in the dead of winter.
The improvement of the energy efficiency of industrial gear motors and gearboxes is a common problem for many gear unit manufacturers and end-users. As is typical of other mechanical components, the radial lip seals used in such units generate friction and heat, thus contributing to energy losses of mechanical systems. There exist today simulation tools that are already helping improve the efficiency of mechanical systems — but accurate models for seal frictional losses need to be developed. In this paper SKF presents an engineering model for radial lip seal friction based on a physical approach.
Gearing is an essential component in conveyors. The material handling industry appears divided between those who favor high-end three-stage helical bevel gearboxes and those who rely on less expensive worm gearing. But there’s an often over-looked alternative, the two-stage helical bevel gearbox.
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.
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.
Volatile aerospace market keeps gear manufacturers guessing.
For the lubrication of open gear drives used in different industrial applications such as cement and coal mills, rotary furnaces, or where the sealing conditions are difficult, semi-fluid greases are often used in preference to fluid oils. For girth gear applications the greases are used with a splash or spray lubrication system. The selection of such greases influences pitting lifetime and the load-carrying capacity of the gears, as well as wear behavior
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.
With today's smaller, hotter - and overloaded - machinery, specifying the correct lubricant is vital.
As gear efficiency is improved in small steps, it is important to be able to distinguish actual improvements from scatter that can occur while testing. An FZG back-to-back gear test rig was used to investigate how the assembly and re-assembly of the same test setup affects the measurements. A spread in torque loss between one assembly and another of the same test setup were observed. Rig conditions also affected the spread in input torque. With knowledge of how the spread in torque loss varies due to assembly, test results could be distinguished between changes due to assembly and actual differences between tests.
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.
Our product focus includes the latest technology in gears and gear drives from the leading manufacturers.
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.
The U.S. Space Shuttle fleet was originally intended to have a life of 100 flights for each vehicle, lasting over a 10-year period, with minimal scheduled maintenance or inspection. The first space shuttle flight was that of the Space Shuttle Columbia (OV-102), launched April 12, 1981. The disaster that destroyed Columbia occurred on its 28th flight, February 1, 2003, nearly 22 years after its first launch.
In most applications, gearbox reliability is critical to the productivity of the overall plant operation. So it follows that when industry is looking at the best ways to increase efficiency, reduce downtime, and increase profitability, gearbox performance and reliability are key factors. Designing for repair, and writing effective repair procedures, can speed the service time, and provide a quality refurbishment. The best practices listed in this article are proven, effective methods used to install and remove bearings, seals, gears, couplings and shafts within a gearbox.
Mean Time Between Failures is a very frequent and broadly used reliability measure of components, systems and devices used mainly in conjunction with electrical and electronic equipment.
conveying system on the varnishing line for a manufacturer of high-end kitchen cabinets were leaking. Oil was dripping on the cabinet parts — ruining the finish. Why were half of the gearboxes leaking?
Where to find the gearboxes, bearings, couplings and other components.
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.
Gearmotor manufacturers find new ways to push the envelope. (With Sidebar on new alternative to planetary gearboxes)
Involute splines are commonly used in gearboxes to connect gears and shafts, especially when high torque is transmitted through the coupling. The load is shared among multiple teeth around the coupling circumference, resulting in higher load capacity than a conventional single key. However, the total load is not equally shared among all spline teeth, mainly because of pitch deviations resulting from the manufacturing process. The load distribution along the spline engagement length is also nonuniform because of tooth misalignments and shaft torsional effects. This paper presents an investigation of the influence of spur gear loads on the load distribution of spline teeth.
This article is designed to help describe the selection process of a reducer to be used in the parcel handling industry. It will go over the different applications for which gearboxes are used throughout parcel handling facilities such as UPS, FedEx and DHL.
Much of the industrial energy being consumed by systems is wasted through inefficiency. For this article, a system will be defined as the following components working together: electrical input power, variable frequency drives, induction motors, gearboxes and transmission elements (chains, belts, etc.).
The world of high horsepower drives often calls for mechanical design to be approached from different perspectives. As motors, gearboxes and machines increase in size, power density can become disproportionate from one driveline component to the next, emphasizing the need for more rugged, robust and compact equipment.
Upgrading to gearboxes with helical gearing can save on energy, maintenance and landfill space.
In recent years, gearbox technology has advanced and original equipment manufacturers (OEMs) have specified required gear oils to meet the lubrication requirements of these new designs. Modern gearboxes operate under severe conditions while maintaining their reliability to ensure end-user productivity. The latest generation of industrial gear lubricants can provide enhanced performance—even under extreme operating conditions—for optimal reliability and reduced cost of operation.
Wind is the talk of the town. It has become especially relevant to the power transmission community where bearings, gears, couplings, motors and gearboxes are providing the equipment for this thriving alternative energy industry. It comes as no surprise that the Windpower 2009 Conference and Exhibition, arriving in Chicago from May 4–7, will be the largest gathering of wind energy professionals and technologies to date.
News Items About gearboxes
1 Wittenstein Welcomes New Generation of Inline Gearboxes (April 30, 2012)
Experience the faces of a new generation of gearboxes with the LP+ Generation 3 from Wittenstein. This new precision gearhead sets new st...
2 Varvel Produces Custom Gearboxes in addition to Standard Offerings (February 16, 2018)
The Varvel Group can produce custom gearboxes to satisfy specific needs including a gearbox developed for an American customer that pro...
3 Groschopp Releases New i-series Planetary Gearboxes (May 6, 2013)
Available in three sizes and multiple gear ratios, Groschopp’s new i-series gearboxes are suitable for applications that have strin...
4 ZF Opens First U.S. Plant for Wind Turbine Gearboxes (October 4, 2011)
ZF Friedrichshafen AG has opened a plant for the production of wind turbine gearboxes in Gainesville near Atlanta, Georgia. As of 2012, t...
5 Gearboxes Offer Range of Drive Requirements (May 6, 2011)
A line of totally sealed, precision right angle gearboxes that feature robust construction and are maintenance-free for a wide range of d...
6 Excel Gear Designs, Prototypes Navy Gun System Gearboxes (September 10, 2009)
Roscoe, IL-based Excel Gear has transitioned from prototype to production of 38:1 ratio gearboxes designed for positioning the gun mount ...
7 Renold Introduces Interchangeable Range of Gearboxes and Couplings (May 24, 2007)
Renold will exhibit its SMXtra interchangeable range of gearboxes and fluid couplings, for quarrying applications, at the Hillhead Exhibi...
8 AutomationDirect Offers Stepper Gearboxes (February 12, 2014)
AutomationDirect’s new SureGear PGCN series of stepper gearboxes is a suitable choice for stepper and other motion control applicat...
9 NKE Offers Rolling Bearings for Gearboxes (June 10, 2014)
NKE Austria offers rolling bearings for industrial gearboxes that meet the efficiency and reliability requirements of a wide range of sectors, such as general machinery, mining, material handling systems and heavy machinery...
10 AutomationDirect Adds Helical Gearboxes to IronHorse Line (June 21, 2016)
AutomationDirect’s IronHorse line of motor products now includes helical gearboxes which provide quiet startup and smooth operation...
11 Drive Lines Servo Gearboxes Offer Versatility for Critical Applications (July 15, 2016)
Servo gearboxes are likely to be specified in an incredibly wide range of applications, from packaging machines to robots, medical equipm...
12 Rino Mechanical Components Inc. Launches E-Series Gearboxes (November 14, 2007)
With a recent upgrade to its mechanical tools, Rino Mechanical Components Inc. unveiled its new E-series of gearboxes. The E-series featu...
13 Ondrives Manufactures Showcase Gearboxes (April 17, 2006)
Ondrives Ltd. of Chesterfield, U.K., manufactured two gearboxes for a pharmaceutical companys teaching purposes. According to th...
14 GE Energy Partners with Chinese Co. To Develop Wind Turbine Gearboxes (April 22, 2006)
GE Energy and Nanjing High Speed & Accurate Gear Company (NGC) have agreed to jointly develop gearboxes for GE's 1.5-megawatt wind tu...
15 Varvel Offers RS and RT Series Worm Gearboxes (January 19, 2018)
The Varvel RS and RT series worm gearboxes demonstrate the company’s versatility and innovation for a variety of demanding applicat...
16 ArvinMeritor Focuses on Automated Manual Gearboxes (April 15, 2006)
ArvinMeritor announced a decision to place greater emphasis on the sales and marketing of the FreedomLine automated manual transmission b...
17 Bosch Rexroth Optimizes Wind Turbine Gearboxes (August 27, 2012)
The competitive pressure as well as the pricing pressure in the wind energy industry is mounting. If the sector wants to continue to expa...
18 Drive Lines Gearboxes Bring Flexibility to Machine Tools (May 23, 2016)
Whether cutting, boring, grinding or shearing, modern machine tools have to meet what at first sight appear to be conflicting operational...
19 KISSsoft Offers Enhanced Heating Calculation for Gearboxes (September 3, 2015)
The efficiency calculation and thermal analysis according to ISO/TR 14179 (module KS2) has been extended with several useful functionalit...
20 GWJ Technology Launches New Version of System Calculation for Gearboxes (March 2, 2015)
GWJ Technology GmbH, a manufacturer of calculation software for machine elements and gears, recently launched a new version of its system...
21 Encoder Ready DC Motors Feature Planetary Gearboxes (July 15, 2010)
Nidal Copal's HG16 series is a RoHS compatible DC motor with planetary gearbox. The 0.63 inch OD (16 mm) DC motor has two axial lengt...