Bush bearing and rack-and-pinion type steering apparatus for automobile using the same

A bush bearing comprising:

• a synthetic resin-made bush having at least one circumferential groove in an outer peripheral surface thereof;
• and an endless annular elastic member which is fitted in the circumferential groove of said bush,
• wherein said bush has a pair of inside inner peripheral surfaces which are disposed axially symmetrically;
• a pair of slits which are each disposed with one of the inside inner peripheral surfaces located therebetween in a circumferential direction, and which allow that inside inner peripheral surface to be movable in a radially inward/outward direction;
• another pair of slits which are each disposed with the other one of the inside inner peripheral surfaces located therebetween in the circumferential direction, and which allow that inside inner peripheral surface to be movable in the radially inward/outward direction;
• and at least one pair of outer inner peripheral surfaces disposed on an outer side of the pair of inside inner peripheral surfaces in a radial direction,
• wherein each of the outer inner peripheral surfaces is adapted to form a gap with a corresponding one of outer peripheral surfaces on a rack teeth side and an opposite side to the rack teeth side of a rack shaft which is inserted and secured in a through hole defined by the pair of inside inner peripheral surfaces and the pair of outer inner peripheral surfaces, and
• wherein each of the inside inner peripheral surfaces at least at its portion is adapted to slidably come into contact with a corresponding outer peripheral surface of said rack shaft, excluding outer peripheral surfaces on the rack teeth side and the opposite side to the rack teeth side of said rack shaft.