A test method based on the condition simulation and a friction and wear test machine featuring in oscillatory movement were set up for self-lubricating spherical plain bearings (SPB). In the machine the condition para...A test method based on the condition simulation and a friction and wear test machine featuring in oscillatory movement were set up for self-lubricating spherical plain bearings (SPB). In the machine the condition parameters such as load, angle and frequency of oscillation and number of test cycles can be properly controlled. The data relating to the tribological properties of the bearing, in terms of friction coefficient, linear wear amount, temperature near friction surface and applied load, can be monitored and recorded simultaneously during test process by a computerized measuring system of the machine. Efforts were made to improve the measurement technology of the friction coefficient in oscillating motion. In result, a well-designed bearing torque mechanism was developed, which could reveal the relation between the friction coefficient and the displacement of oscillating angle in any defined cycle while the curve of friction coefficient vs number of testing cycles was continuously plotted. The tribological properties and service life of four kinds of the bearings, i.e, the sampleⅠ-Ⅳ with different self-lubricating composite liners, including three kinds of polytetrafluoroethylene (PTFE) fiber weave/epoxy resin composite liners and a PTFE plastic/copper grid composite liner, were evaluated by testing, and the wear mechanisms of the liner materials were analyzed.展开更多
In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is desc...In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.展开更多
For tribological investigations of automotive brakes, both full and reduced scale brake dynamometers are used. Full scale brake dynamometers test the entire brake system, including caliper, brake pad, brake disk, whee...For tribological investigations of automotive brakes, both full and reduced scale brake dynamometers are used. Full scale brake dynamometers test the entire brake system, including caliper, brake pad, brake disk, wheel suspension, etc. The AUT （automated universal tribotester） is a reduced scale brake dynamometer with a pin on disk test configuration. A brake pad specimen is used as the pin and a brake disk is used as the counter body. Compared to full scale brake dynamometers, the AUT encounters fewer influences from the test systems themselves. The AUT was developed at the Institute of Dynamics and Vibrations in Braunschweig. It can be used for high frequency analyses of the coefficient of friction, and investigations of the boundary layer between brake pad and disk, along with the associated NVH behaviors. A digital camera and two laser triangulation sensors are used for optical investigations of the brake pad and brake disk [1, 2]. The focus of this paper is the development of a new control feature of the AUT. The AUT employs a compactRIO from National Instruments as its measurement and control device. The velocity and position control loops are implemented in the compactRIO＇s FPGA along with high frequency synchronous measurement data acquisition. Its real-time controller coordinates the measurement and the storage of measured data. The test device has three degrees of freedom： normal load, sliding speed, and temperature, all of which can be defined by the user for each brake application. New control strategies based on the friction force as a feedback parameter allow for the implementation of new features. In this paper, the realization of measurements with constant friction power throughout the friction procedure will be shown. This new degree of freedom in the friction measurements enables investigations to be carried out in which it is necessary to bring a specific energy in the friction process. In this paper, a p-controller on the real-time system calculates the required set point for the position control loop. The new feature is verified through a benchmark test [6]. Based on the control loop with the friction force as the feedback parameter, it is also possible to emulate in-stop brakes with virtual inertia. In this way, many other types of full scale brake dynamometers can be simulated. The long-term aim is the identification of the influence of test devices on the test results.展开更多
针对现阶段圆柱滚子轴承摩擦力矩试验机测量载荷较小以及大径向载荷条件下测量精度不高的问题,基于平衡法研制了圆柱滚子轴承摩擦力矩试验机,试验机主体为卧式结构,最大载荷可施加至10 k N,可以在不同转速和润滑条件下测量圆柱滚子轴承...针对现阶段圆柱滚子轴承摩擦力矩试验机测量载荷较小以及大径向载荷条件下测量精度不高的问题,基于平衡法研制了圆柱滚子轴承摩擦力矩试验机,试验机主体为卧式结构,最大载荷可施加至10 k N,可以在不同转速和润滑条件下测量圆柱滚子轴承的摩擦力矩。基于试验分析了径向载荷对圆柱滚子轴承摩擦力矩的影响规律,结果表明圆柱滚子轴承摩擦力矩随径向载荷的增加逐渐增大,摩擦力矩测量值与理论计算值相差较小,验证了圆柱滚子轴承摩擦力矩试验机的实用性。展开更多
文摘A test method based on the condition simulation and a friction and wear test machine featuring in oscillatory movement were set up for self-lubricating spherical plain bearings (SPB). In the machine the condition parameters such as load, angle and frequency of oscillation and number of test cycles can be properly controlled. The data relating to the tribological properties of the bearing, in terms of friction coefficient, linear wear amount, temperature near friction surface and applied load, can be monitored and recorded simultaneously during test process by a computerized measuring system of the machine. Efforts were made to improve the measurement technology of the friction coefficient in oscillating motion. In result, a well-designed bearing torque mechanism was developed, which could reveal the relation between the friction coefficient and the displacement of oscillating angle in any defined cycle while the curve of friction coefficient vs number of testing cycles was continuously plotted. The tribological properties and service life of four kinds of the bearings, i.e, the sampleⅠ-Ⅳ with different self-lubricating composite liners, including three kinds of polytetrafluoroethylene (PTFE) fiber weave/epoxy resin composite liners and a PTFE plastic/copper grid composite liner, were evaluated by testing, and the wear mechanisms of the liner materials were analyzed.
基金National Natural Science Foundation of China(No.90923027No.51175405)
文摘In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.
文摘For tribological investigations of automotive brakes, both full and reduced scale brake dynamometers are used. Full scale brake dynamometers test the entire brake system, including caliper, brake pad, brake disk, wheel suspension, etc. The AUT （automated universal tribotester） is a reduced scale brake dynamometer with a pin on disk test configuration. A brake pad specimen is used as the pin and a brake disk is used as the counter body. Compared to full scale brake dynamometers, the AUT encounters fewer influences from the test systems themselves. The AUT was developed at the Institute of Dynamics and Vibrations in Braunschweig. It can be used for high frequency analyses of the coefficient of friction, and investigations of the boundary layer between brake pad and disk, along with the associated NVH behaviors. A digital camera and two laser triangulation sensors are used for optical investigations of the brake pad and brake disk [1, 2]. The focus of this paper is the development of a new control feature of the AUT. The AUT employs a compactRIO from National Instruments as its measurement and control device. The velocity and position control loops are implemented in the compactRIO＇s FPGA along with high frequency synchronous measurement data acquisition. Its real-time controller coordinates the measurement and the storage of measured data. The test device has three degrees of freedom： normal load, sliding speed, and temperature, all of which can be defined by the user for each brake application. New control strategies based on the friction force as a feedback parameter allow for the implementation of new features. In this paper, the realization of measurements with constant friction power throughout the friction procedure will be shown. This new degree of freedom in the friction measurements enables investigations to be carried out in which it is necessary to bring a specific energy in the friction process. In this paper, a p-controller on the real-time system calculates the required set point for the position control loop. The new feature is verified through a benchmark test [6]. Based on the control loop with the friction force as the feedback parameter, it is also possible to emulate in-stop brakes with virtual inertia. In this way, many other types of full scale brake dynamometers can be simulated. The long-term aim is the identification of the influence of test devices on the test results.
文摘针对现阶段圆柱滚子轴承摩擦力矩试验机测量载荷较小以及大径向载荷条件下测量精度不高的问题,基于平衡法研制了圆柱滚子轴承摩擦力矩试验机,试验机主体为卧式结构,最大载荷可施加至10 k N,可以在不同转速和润滑条件下测量圆柱滚子轴承的摩擦力矩。基于试验分析了径向载荷对圆柱滚子轴承摩擦力矩的影响规律,结果表明圆柱滚子轴承摩擦力矩随径向载荷的增加逐渐增大,摩擦力矩测量值与理论计算值相差较小,验证了圆柱滚子轴承摩擦力矩试验机的实用性。
