Rack bush

A rack bush constituting a rack and pinion type steering system and supporting a rack shaft in which rack teeth are formed at one circumferential portion, the rack hush comprising:

• an annular bush main body into which the rack shaft is inserted, and which is divided, in a circumferential direction, into two portions including a rack teeth-side portion located on the same side as the rack teeth in the circumferential direction and a back face-side portion other than the rack teeth-side portion;
• and
• a rigidity reducing portion that is provided in the rack teeth-side portion, and that makes a rigidity of the rack teeth-side portion lower than a rigidity of the back face-side portion,
• wherein the rigidity reducing portion includes an axial groove extending in an axial direction of the bush main body,
• the axial grooves are respectively provided at least at boundaries at two circumferential portions between the rack teeth-side portion and the hack face-side portion in the bush main body, and in a region other than the boundaries in the rack teeth-side portion,
• each of the axial grooves extends from a first end or a second end, which is located at an opposite side of the first end, of the rack teeth-side portion in the axial direction to an intermediate position in the rack teeth-side portion, and
• at least one axial groove extends from the first end of the rack teeth-side portion toward the second end of the rack teeth-side portion in the axial direction to the intermediate position in the rack teeth-side portion, and other axial grooves extend from the second end of the rack teeth-side portion toward the first end of the rack teeth-side portion in the axial direction to the intermediate position in the rack teeth-side portion.