Synthetic resin-made sliding bearing

A synthetic resin-made sliding bearing adapted to be interposed between a rack shaft and a gear case by being fixed to an inner peripheral surface of the gear case in order to support the rack shaft inside the gear case movably in an axial direction, comprising:

• a semiannular bearing base portion which, at a semicylindrical outer peripheral surface thereof, is adapted to be brought into contact with the inner peripheral surface of the gear case and has a notched portion on a rack teeth side of the rack shaft;
• a first bearing portion which has a circular arc-shaped outer peripheral surface adapted to be brought into contact with the inner peripheral surface of the gear case and extends integrally in the axial direction from one axial semiannular end face of said bearing base portion;
• and
• a pair of second bearing portions which extend integrally in the axial direction from the one axial semiannular end face of said bearing base portion in such a manner as to sandwich said first bearing portion through each of a pair of slits in a direction about an axis,
• wherein said first bearing portion has a first bearing surface which is adapted to oppose an outer peripheral surface of the rack shaft on an opposite side to the rack teeth side of the rack shaft with a clearance therebetween, and each of said second bearing portions has a second bearing surface which is adapted to be brought into slidable contact with the outer peripheral surface of the rack shaft, and
• wherein the first bearing surface is adapted to be brought into contact with the outer peripheral surface of the rack shaft by a displacement of the rack shaft exceeding a fixed amount in a direction perpendicular to the axial direction and directed from the rack teeth side of the rack shaft toward the opposite side to the rack teeth side of the rack shaft.