Evaluation of spinning friction from a thrust ball bearing

6th ModTech International Conference - Modern Technologies in Industrial Engineering

Alaci, S.^1 ; Ciornei, F.-C.^1 ; Romanu, I.-C.^1 ; Ciornei, M.-C.^2

Stefan Cel Mare University of Suceava, Department of Mechanics and Technologies, Universitatii Street, No. 13, Suceava

720229, Romania^1

Carol Davila University of Medicine and Pharmacy, Bucharest-Romania, Department Clinic 2, Blvd. Eroii Sanitari, No. 8, Bucharest

050474, Romania^2

关键词: Angular acceleration;    Axis of rotation;    Coefficient of frictions;    Function characteristic;    Moment of inertia;    Parabolic functions;    Rotation motions;    Spinning motions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/400/2/022002/pdf
DOI  :  10.1088/1757-899X/400/2/022002

来源: IOP

【 摘 要 】

The existence of ball-raceway relative motion imposes the simultaneous occurrence of spinning motion about an axis parallel to the normal in the contact point and a rolling motion about an axis contained in the common tangent plane intersecting the axis of the ball bearing. For the separate characterization of the two friction torques - spinning and rolling moments, the devices to be used must be specially designed. For finding the spin torque or the rolling torque, the test-rigs used must contain a housing washer and a ball between which only spinning or rolling motion, respectively, exists. A test rig for evaluation of the spinning moment assumes ensuring the rotation motion about the normal in the contact point and additionally allows for estimation of the friction torque. The main inconvenience of such a device is the necessity of bearings capable to ensure a fixed position for the axis of rotation of the ball. The work proposes a simple and precise method for estimation of the spin moment by analyzing the motion of an axi-symmetric body that is in contact with the housing washer of a thrust ball bearing. The experimental data are interpolated using a parabolic function which is a function characteristic to the rotation motion with constant friction torque. The (constant) angular acceleration is found from the law of motion and together with the moment of inertia of the body is used in estimation of the spinning torque. This moment is assumed equal to the one found experimentally and thus results the value of the coefficient of friction from the contact area. The concordance between the value of the coefficient of friction obtained by the present method and the values from literature validates the proposed technique.