Keywords: rolling bearing, inactive self-lock bearing, structure, improvement
　　Inactive self-lock bearing is a kind of bearing with locking function, the active side can input torque to drive the rotation of the inactive side, while the inactive side can produce self-locking under the effect of load, which can be used to supplying for ball screw instead of T-shaped thread transfer. Since the complicated processing and measurement for the dual groove of original inactive self-lock bearing’s inner & outer ring, this paper presents the design program for structure improvement on inactive self-lock bearing, as follows:
　　1 Original structure
　　The original structure for inactive self-lock bearing is shown in Picture 1, composed by two set of exactly the same components and one set of component in the middle. The component for the left (or right)of bearing is actually the double-row radial ball bearing with the standard keyway on its inner ring, meanwhile the inner ring to extend in the way of half block to make bearing rotate or lock by pushing the locking key. The set of component in the middle is locking component, consists of locking key, spring, locking ring and locking pin.

l.outer ring；2.steel ball；3.inner ring on the inactive side；4.needle (stop pin); 5.locking ring；6.spring；7.locking key；8.inner ring on the active side
Picture 1 Assembly drawing for the inactive self-lock bearing

　　The self-locking principle is: after the bearing assembly completed, it has divided into the active side and inactive side. When the body make bearing’s inner ring on the active side positively & negatively rotate, pressure to overcome the spring can push the locking key from the locking ring, thus to drive the inner ring on the inactive side to rotate. When the active side stop inputing power, the inactive side cannot drive the active side to rotate no matter impose the positive torque or the negative torque, then the locking key and the locking ring tightly locked with friction in the effect of the inactive torque and the spring power, i.e., inactive self-locking, finally, the entire body stop running.
　　2 Improved structure
　　The improved structure consists of 8 parts, as shown in Picture 2. The original inner ring and outer ring respectively replaced by the standard bearing’s inner ring and outer ring, so as to avoid troubles in processing the dual groove for inner & outer ring. What’s more, the processing accuracy is easy to guarantee, just to ensure the accuracy of concentricity and inner diameter for the inner ring, thus to form the interference fit with the standard bearing, and also to ensure the concentricity after assembly. However, processing for the locking ring is still the same except for width increasing.

l、8．standard bearing；2．locking ring；3．needle (longer than the original structure)；4、7．inner ring；5．spring；6．locking key
Picture 2 Assembly drawing for the improved structure

　　The improved bearing has simple & compact structure, the processing is quite easy as well, even non-professional bearing manufacturers could produce, which has greatly enhance production efficiency, meanwhile with the same effect as the orignial bearing structure.