Abstract: A tire vulcanization mold in which a surface roughness in the groove molding portion of the tread molding surface is made smaller than a surface roughness in the land portion molding portion, in which a surface roughness in the groove molding portion is minimized to 0.12 ?m or less in a range including at least a main groove molding portion, and in which a surface roughness in the land portion molding portion is made to be 3.2 ?m or more, is used to manufacture a tire, and when cleaning the tread molding surface, the tread molding surface is irradiated with a laser beam to remove contaminant adhered to the tread molding surface.

Abstract: A rack bar includes: a rack tooth row including a plurality of rack teeth meshing with pinion teeth; a hardened layer provided continuously over an entire circumference of the rack tooth row; and a center portion provided inside the hardened layer and having lower hardness than the hardened layer. When the rack bar is viewed in an axial direction of the rack bar, a depth of the hardened layer from the following positions i), ii), and iii) increases in this order: i) a bottom land of the rack teeth; ii) a side of the rack bar relative to the bottom land; and iii) a back of the rack bar relative to the bottom land.

Abstract: A rack bar includes: a rack tooth row including a plurality of rack teeth meshing with pinion teeth; a hardened layer provided continuously over an entire circumference of the rack tooth row; and a center portion provided inside the hardened layer and having lower hardness than the hardened layer. When the rack bar is viewed in an axial direction of the rack bar, a depth of the hardened layer from the following positions i), ii), and iii) increases in this order: i) a bottom land of the rack teeth; ii) a side of the rack bar relative to the bottom land; and iii) a back of the rack bar relative to the bottom land.

Abstract: A fitting structure includes an annular seal member; a first fitting member including a first tubular fitting portion having a tubular shape, a first holding portion that contacts the seal member from a first axial end side, and a first restricting portion provided at a position different from a position of the first holding portion; and a second fitting member including a second tubular fitting portion having a tubular shape that is fitted to the first tubular fitting portion from a second axial end side, a second holding portion that contacts the seal member from the second axial end side, and a second restricting portion that contacts the first restricting portion from the second axial end side in a state where the seal member is compressed by a prescribed amount between the first holding portion and the second holding portion.

Abstract: A fitting structure includes an annular seal member; a first fitting member including a first tubular fitting portion having a tubular shape, a first holding portion that contacts the seal member from a first axial end side, and a first restricting portion provided at a position different from a position of the first holding portion; and a second fitting member including a second tubular fitting portion having a tubular shape that is fitted to the first tubular fitting portion from a second axial end side, a second holding portion that contacts the seal member from the second axial end side, and a second restricting portion that contacts the first restricting portion from the second axial end side in a state where the seal member is compressed by a prescribed amount between the first holding portion and the second holding portion.

Abstract: With a rack-and-pinion mechanism, an impact force is absorbed and reduction in assembling performance is suppressed. An annular fitting groove (51) that extends in the circumferential direction of a rack guide (41) is formed in an outer peripheral face (41a) of the rack guide (41), and an O-ring (52) is fitted in the fitting groove (51) in a state in which the axial movement of the O-ring (52) is restricted. A communication groove (61) that provides communication between an internal space (55), defined by the fitting groove (51) and the O-ring (52), and the outside of the rack guide (41) is formed in the rack guide (41).

Abstract: With a rack-and-pinion mechanism, an impact force is absorbed and reduction in assembling performance is suppressed. An annular fitting groove (51) that extends in the circumferential direction of a rack guide (41) is formed in an outer peripheral face (41a) of the rack guide (41), and an O-ring (52) is fitted in the fitting groove (51) in a state in which the axial movement of the O-ring (52) is restricted. A communication groove (61) that provides communication between an internal space (55), defined by the fitting groove (51) and the O-ring (52), and the outside of the rack guide (41) is formed in the rack guide (41).