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.

A thermo-mechanical model of a splash lubricated one-stage gear unit is presented. This system corresponds to a first step towards the design of a hybrid vehicle gearbox that can operate up to 40,000 rpm on its primary shaft. The numerical model is based on the thermal network method and takes into account power losses due to teeth friction, rolling-elements bearings and oil churning. Some calculations underline that oil churning causes a high amount of power loss. A simple method to reduce this source of power losses is presented, and its influence on the gear unit efficiency and its thermal capacity is computed.

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 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.

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.

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.

When talking about high-end machining or manufacturing applications that include direct-drive technology, one of the key advantages of utilizing this particular transmission method is its endurance. Because of the very nature of direct-drive motors they are able to operate at peak performance levels indefinitely — without any kind of wear or aging — as long as the motor isn’t pushed past its capacity. Unfortunately, because this isn’t a perfect world, unexpected things can happen which can cause the motor to overheat. Whether the heat source is due to a parameter being input incorrectly, or an unexpected external force causing more resistance than expected — it is important to have certain forms of thermal protection in place. Since torque motors are built in such a way that they cannot be repaired and yet maintain their efficiency, it is vital to prevent any overheating — thus precluding the need to purchase a new one.

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.

One of the key challenges in the mining industry today is maintaining throughput in the face of ore grade quality that has declined by 40 percent in the last decade.

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.