Half thrust bearing

A semi-annularly shaped half thrust bearing for receiving axial force of a crankshaft of an internal combustion engine, the half thrust bearing comprising a slide surface for receiving the axial force and a back surface on an opposite side thereto, and defining an axial direction, a circumferential direction and a radial direction, wherein the slide surface comprises:

• at least two oil grooves each radially extending from a radially inner end to a radially outer end of the slide surface with a constant width;
• a plurality of pad surfaces located on both sides of each oil groove in the circumferential direction, and having an axial thickness from the back surface to the pad surface that is constant;
• at least two first inclined surfaces, each first inclined surface being formed between the oil groove and the pad surface so as to be located on a forward side of the oil groove in a rotation direction of the crankshaft, and having an axial thickness from the back surface to the first inclined surface that is smaller in the circumferential direction from a pad surface side toward an oil groove side;
• and
• at least two second inclined surfaces, each second inclined surface being formed between the oil groove and the pad surface so as to be located on a backward side of the oil groove in the rotation direction of the crankshaft, and having an axial thickness from the back surface to the second inclined surface that is smaller in the circumferential direction from the pad surface side toward the oil groove side, wherein
• each of the first inclined surfaces and the second inclined surfaces has a circumferential length which varies along the radial direction, and comprises a ridge portion which extends circumferentially at a radial position where the circumferential length is minimum, wherein the circumferential length of each of the first inclined surfaces and the second inclined surfaces is formed so as to become greater from the ridge portion toward the radially inner end along the radial direction and become greater from the ridge portion toward the radially outer end along the radial direction,
• the axial thickness of each of the first inclined surfaces and the second inclined surfaces is formed so as to be maximum at the ridge portion in the radial direction, to become smaller from the ridge portion toward the radially inner end, and to become smaller from the ridge portion toward the radially outer end, and
• the ridge portions of the first inclined surface and the second inclined surface located on both sides of each oil groove in the circumferential direction are formed at the same radial position on an outer side relative to a center line of the half thrust bearing in the radial direction.