Cylinder liner and sealing structure for cylinder liner

A cylinder liner mounted on a cylinder block of an internal

• combustion engine and slidably accommodating a piston along an axial direction, the cylinder liner comprising:
• a small diameter portion configured to form a cooling water passage between the small diameter portion and an inner peripheral surface of the cylinder block;
• a large diameter portion disposed adjacent to the small diameter portion in the axial direction and formed to have a larger diameter than the small diameter portion;
• and
• at least one seal groove formed on an outer peripheral surface of the large diameter portion in an annular shape along a circumferential direction,
• wherein the large diameter portion includes
• a one-side wall portion formed between the cooling water passage and a cooling-water-passage-side seal groove which is a seal groove disposed closest to the cooling water passage in the axial direction, and
• an other-side wall portion disposed farther from the cooling water passage than the cooling-water-passage-side seal groove is in the axial direction,
• wherein the one-side wall portion is configured to have, in at least part in a circumferential direction including a thrust direction of the piston, a larger distance to the inner peripheral surface of the cylinder block than a distance from the other-side wall portion to the inner peripheral surface of the cylinder block, and
• wherein the seal member includes
• an O-ring, and
• a back-up ring disposed closer to the cooling water passage than the O-ring is, the back-up ring being configured to have, in at least part in the circumferential direction including the thrust direction of the piston, a smaller distance to the inner peripheral surface of the cylinder block than a distance from the one-side wall portion to the inner peripheral surface of the cylinder block.

A cylinder liner mounted on a cylinder block of an internal combustion engine and slidably accommodating a piston along an axial direction, the cylinder liner comprising:

• a small diameter portion configured to form a cooling water passage between the small diameter portion and an inner peripheral surface of the cylinder block;
• a large diameter portion disposed adjacent to the small diameter portion in the axial direction and formed to have a larger diameter than the small diameter portion;
• and
• at least one seal groove formed on an outer peripheral surface of the large diameter portion in an annular shape along a circumferential direction,
• wherein the large diameter portion includes a one-side wall portion formed between the cooling water passage and a cooling-water-passage-side seal groove which is a seal groove disposed closest to the cooling water passage in the axial direction,
• wherein the one-side wall portion has a cooling water passage side surface facing the cooling water passage, the cooling water passage side surface being formed such that, in at least part in a circumferential direction including a thrust direction of the piston, a distance to the inner peripheral surface of the cylinder block gradually increases with an increase in distance from the seal groove,
• wherein the inner peripheral surface of the cylinder block includes a curved surface configured so that the distance from the cylinder liner to the curved surface decreases toward the seal groove, and
• wherein the curved surface includes
• a first-curved-surface which is convex away from the small diameter portion, and
• a second-curved-surface which is convex toward the small diameter portion, the second-curved-surface being connected to the first-curved-surface via an inflection point,
• wherein the cooling water passage side surface includes an end in the axial direction,
• the other end located on an opposite side of the seal groove across the end, and
• wherein the other end of the cooling water passage side surface is located, in the axial direction, between the seal groove and a middle point of the second-curved-surface.