Study of the BJ Ball Rotational Motion

Abstract

The ball-fixed joint (BJ) is one of the fixed type constant-velocity-joint (CVJ), and it is widely used in front wheel drive systems of the car. For the recent needs of good mileage and lightweight for the car, the compact CVJ that reduced ball size and increased ball number is developed, and mass-produced. Meanwhile, there is a possibility that the solution of tribological subject of long life under high pressure bring more lightweight and compact design. Then the practical development of new grease is generally performed. But because of non-understanding about characteristics of contact surfaces, e.g. relative slip velocity or spin, the development is inefficient. On the other hand, the pole and the equator of the oil stain were sometimes observed on the balls after endurance test of BJ. The solution of the formation mechanism of the pole and the equator is one subject for understanding the characteristics of the contact surfaces. In this paper, the formation mechanism of the pole and the equator is investigated by measuring the rotational motion of the ball of BJ with the hall sensors in the endurance test, and by using dynamic analysis together.