Papers by Keyword: Friction Torque

Abstract: Ball bearings are crucial components in various machinery and mechanical systems, finding applications across numerous industries such as automotive, aerospace, manufacturing, robotics, and household appliances. Minimizing friction and wear in the bearings is essential to enhance the efficiency, reliability, and lifespan of equipment. Friction moments in ball bearings occur due to rolling-sliding motion at the ball-race contact and sliding between the ball and cage. The magnitude of these friction moments depends on factors such as surface topography, load, and speed. Understanding how surface topography influences the friction moments in these bearings is crucial. This paper investigates the effect of surface roughness on the friction moment between the ball and race contact, as well as between the ball and cage contact. An analytical model is employed to estimate the friction torque within ball bearings, considering the total friction torque generated at the contact points between the balls and the race, as well as at the ball-cage interface. A mixed elastohydrodynamic lubrication model is used to estimate the friction coefficient at these contact points.

Abstract: In our previous paper[6], the effects of the retainer wear failure on the friction torque were investigated. In the present paper, to research the failure of the retainers of the PEEK-alumina ball bearings tested under dry rolling contact, the upper and bottom surfaces and the sections of the retainer pockets were observed. The wear damage was found on the surface of the upper and bottom surfaces. On the sections of the pocket, the changes due to wear at the pocket edge was found. On the worn curves of the sections, large scatter of the curvature center positions were numerically calculated in both specimens. The balls moved relatively for the retainer unit to the upper or bottom sides. These results indicate that the wear changed the pocket shape, and the ball could not become to keep the position for the retainer unit. The wear of the pocket caused the failure of the retainer.

Abstract: The rolling contact fatigue of PEEK-alumina ball bearings in non-lubrication was tested under 500 N and 600 N. During the tests, the friction torque was measured. The retainers under both conditions broke during the tests, and rubbed on the upper and bottom races. The friction features were not different between 500 N and 600 N. However, the black colored surfaces on the races and retainer were identified only in the test under 600 N. The wear loss of the bearing tested under 600 N was larger than that under 500 N. From these results, the specimen under 600 N received the heavier wear damages than that under 500 N, and the worn surface was not related to the friction torque. The wear damages of the inner elements and the outer rings in the retainer were larger than those of the races and 9-alumina balls in both specimens.

Abstract: The paper presents experimental results of wear resistance measurements of anti-friction coatings of bimetal fluid-film bearings. As a result, nature and peculiarities of wear process of anti-friction coatings and steel base have been identified. An analysis of antifriction properties of studied copper-based coatings is presented. The paper also features recommendations for application of the studied coatings obtained by means of gas-flame spraying.

Abstract: In this research an experimental test rig and method to measure friction torque from screw-nut assemblies is presented. The experimental test rig uses to measure friction torque an elastic cylinder bush with strain gauge transducers. The frictions torque and the traction force from the threaded assembly are transmitted to the elastic cylinder bush and produce elastic deformations. The elastic cylinder is calibrated in order to establish a correlation between elastic deformation and force of solicitation. In order to measure the experimental data the MGCPlus data acquisition system is used. The experimental results obtained are presented, consisting in the dependence between friction torques and axial traction force occurred in the screw.

Abstract: In this paper, in order to realize friction torque measurement and assembly behavior analysis of arc structure servo mechanism (ASSM), a general measurement system applied, meanwhile structural characteristics and performance of the ASSM are analyzed. Based on the fundamental of electrical method, the system is built up by the principle of vertical structure in line. So the system can applied to all kinds of ASSM by replacing the U-shape frame which suits to the target servos. The experiment is carried out on a certain type, the mean value of dynamic friction torque is about 1.00Nm, and the variance of measured data is about 0.01. The results indicate that the measurement system can measure friction torque and its inhomogeneity effectively and can be used in measurement of friction torque on other ASSM.

Abstract: The subject of this paper was the presentation of a holistic, fully-temperature-coupled FE model of inertia friction welding based on the modified friction law, which divided the friction welding process into beginning friction stage and steady equilibrium friction stage. At each of the stage Coulomb friction model and shear friction model were adopted respectively. The present FE model predicted the temperature of the welding joint as well as variation of friction torque and relative rotating velocity of the work-piece during the welding process. The evolution of friction torque and rotating velocity were compared with the experimental measurement. They showed a good agreement between them.

Abstract: A composite control scheme is proposed to solve the problems of friction toque and carrier disturbance lag in the stabilized loop of inertial stabilized platform. Based on analysis of composite control structure, the performance of single rate loop, double rate loop and composite control in the inhibition of carrier disturbance, friction torque and sensor noise are compared. In order to further verify the composite control method, an experimental setup is built. The experimental results show that: when the disturbance is 1deg-1Hz sinusoidal signal, the peak value of residual error of the single rate loop is 0.055 deg, the double rate loop is 0.031deg, and the composite control is the 0.0188deg, so the performance of isolation carrier disturbance of platform is effectively improved.

Abstract: Wire race ball bearing with large radial size and small axial size, saves space extremely, and is widely used in rotary devices of large machineries. This paper establishes a mathematical model of optimization design of rectangular cross-sectional wire race ball bearing,and considers minimum friction torque as objective function, and analyses constraints of contact intensity and design specifications of wire race ball bearing, and forges an optical design method that determines the number of balls, the diameter of ball, the contact angle and the diameter of ball center circle as optimal design parameters, to attain the purpose of extending bearings life. Comparing results of Optimization with original sample, the friction torque of ball that bears maximum load reduces by 10.20%. This method provides a reference for conducting further scientific researches on wear of wire race ball bearing.

Abstract: The friction pair for bellows mechanical seal as a friction element is one of the key components for it. In this research, by based on the computational fluid dynamics (CFD) numerical theory, using the Fluent software, corresponding model and parameters, the fluid-film between the clearance of the sealing ring friction pair for the bellows mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions is numerically simulated, the relationship between the carrying-capacity of the fluid-film and the temperature, the viscosity of the fluid-film, the relationship between friction torque of the fluid-film and the speed, viscosity of the fluid-film, the influence factor of leakage are obtained. The researching results provide the scientific basis for the optimization designing of the high parameter bellows mechanical seals.