Browse Topic: Bearings
This test method outlines the standard procedure for measuring the radial and axial internal clearance of rolling element bearings used in airframe controls.
This method outlines the standard procedure for testing the hardness of bearing components. Bearings covered by this test method shall be any rolling element bearing used in airframe control.
This test method outlines a standard procedure for performing cyclic reversing load testing on oscillating sliding bearings. The wear data from these tests is to be used for qualification requirements and to establish bearing design criteria.
In this paper, a systematic and in-depth study is carried out on the key engineering problem of the accurate calculation of the flexural capacity of L-shaped concrete-filled steel tubular columns. Based on the basic framework of mechanics theory, the basic design principle of reinforced concrete members is integrated, and the nonlinear characteristics of steel and concrete materials in the process of stress are mainly considered, such as steel yield strengthening, concrete compression damage, etc., and the ultimate bending moment calculation model which is more suitable for the actual stress state is constructed. Through rigorous theoretical derivation and multi-parameter comparative analysis, the final formula for calculating the bearing capacity of special-shaped columns not only has clear mechanical concept support, but also systematically defines the scope of application of the calculation method. The verification results show that the established calculation method not only meets
This standard covers plain and flanged sleeve bearings which are self-lubricating by incorporating polytetrafluoroethylene (PTFE) in a liner in the bore for use in a temperature range of -65 to +250 °F (-54 to +121 °C).
This standard covers all types of manually operated high pressure oxygen, cylinder shut off valves for use in commercial aircraft. It is intended that the valve shall be attached to a pressure cylinder storing oxygen under a nominal pressure of 12.76 MPa (1850 psig) at 21 °C (70 °F). Upon opening the valve, oxygen will be permitted to discharge from the storage cylinder to the valve outlet and to other downstream components of the oxygen system. It shall also be possible to recharge the cylinder through the valve.
An important characteristic of battery electric vehicles (BEVs) is their noise signature. Besides tire and wind noise, noise from auxiliaries as pumps, the electric drive unit (EDU) is one of the major contributors. The dynamic and acoustic behavior of EDUs can be significantly affected by production tolerances. The effects that lead to these scatter bands must be understood to be able to control them better and thus guarantee a consistently high quality of the products and a silent and pleasant drive. The paper discusses a simulation driven approach to investigate production tolerances and their effect on the NVH behavior of the EDU, using high precision transient multi-body dynamic analysis. This approach considers the main effects, influences, and the interaction from elastic structures of electric motor and transmission with accurate gear contact models in a fully coupled way. It serves as virtual end of line test, applicable in all steps of a new EDU development, by increasing
Plastic materials are used for a wide variety of spacecraft applications including seals, bearings, fasteners, electrical insulators, thermal isolators, and radomes. Selecting plastics for use in space is complex due to wide operating temperature ranges, vacuum conditions, and exposure to radiation and atomic oxygen. Additionally, some spacecraft applications require sealing flammable propellants such as hydrogen and oxygen. This article will present some design considerations when selecting plastics for use in spacecraft. It will provide rich data on the performance characteristics of plastics as well as examples of successful spacecraft applications.
Bearings are essential mechanical components that support external loads and facilitate rotational motion. With the increasing demand for high-performance applications in industries such as semiconductors, aerospace, and robotics, the need for accurate and robust performance evaluation has intensified. Traditionally, bearing performance has been assessed using static or quasi-static theoretical approaches. However, these methods are limited in their ability to capture time-dependent behaviors, which are critical in real-world applications. In this study, a rigid body dynamics analysis was proposed to evaluate the time-dependent behavior of bearings. The methodology was first applied to a deep groove ball bearing, and the results were compared with those obtained from bearing theory to validate the approach. Subsequently, the method was extended to an automotive wheel bearing, and the time-dependent contact angles and ball loads were analyzed under axial and radial loading conditions
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