STRUCTURE OF BUSH BEARING

摘要

A structure of a bush bearing includes: a bush on which a groove is formed; and an endless annular-shaped elastic member which is installed in the groove of the bush, and that supports a rack shaft, in which an inner circumferential surface of the bush includes a first inner circumferential surface that is in slide contact with an outer circumferential surface of the rack shaft, which is positioned opposite to a formation position of rack teeth, a second inner circumferential surface that faces the outer circumferential surface of the rack shaft with a gap interposed between the outer circumferential surface and the second inner circumferential surface, and the groove formed in a formation range of the first inner circumferential surface has a depth shallower than that of the groove formed in a formation range of the second inner circumferential surface.

主权项

1. A structure of a bush bearing comprising:
a bush on which a groove is formed along a circumferential direction in an outer circumferential surface of the bush; and an endless annular-shaped elastic member which is installed in the groove of the bush, and that supports a rack shaft in such a manner that the rack shaft is slidable relative to a gear housing, wherein an inner circumferential surface of the bush includes a first inner circumferential surface and a second inner circumferential surface, the first inner circumferential surface is formed over an angular range greater than 180° about an axial center of the bush, and is in slide contact with an outer circumferential surface of the rack shaft, which is positioned opposite to a formation position of rack teeth formed on the rack shaft, the second inner circumferential surface has a diameter larger than that of the first inner circumferential surface, and faces the outer circumferential surface of the rack shaft with a gap interposed between the outer circumferential surface and the second inner circumferential surface, the groove formed in a formation range of the first inner circumferential surface has a depth shallower than that of the groove formed in a formation range of the second inner circumferential surface, and in a state where a portion of the endless annular-shaped elastic member, which is positioned opposite to the formation position of the rack teeth has a radial deformation margin larger than that of a portion of the endless annular-shaped elastic member, which is positioned at the formation position of the rack teeth, the endless annular-shaped elastic member is in close contact with an inner circumferential surface of the gear housing.