Abstract: An oil seal for reciprocation motion including a seal main body, a resin backup ring, and a holding member. The seal main body includes a seal lip that can be in sliding contact with a reciprocating shaft. The backup ring is disposed such as to support the seal lip from the atmosphere side to ensure durability of the seal lip. In the backup ring, at least a single annular groove is provided on the inner peripheral surface opposing the reciprocating shaft. The annular groove can hold a lubricating material. The holding member holds the backup ring between the holding member and the seal main body in a sandwiched-state. The inner peripheral surface of the backup ring forms a taper that increases in diameter from a sealed side towards an atmosphere side in the axial direction.

Abstract: An oil seal for reciprocation motion including a seal main body, a resin backup ring, and a holding member. The seal main body includes a seal lip that can be in sliding contact with a reciprocating shaft. The backup ring is disposed such as to support the seal lip from the atmosphere side to ensure durability of the seal lip. In the backup ring, at least a single annular groove is provided on the inner peripheral surface opposing the reciprocating shaft. The annular groove can hold a lubricating material. The holding member holds the backup ring between the holding member and the seal main body in a sandwiched-state. The inner peripheral surface of the backup ring forms a taper that increases in diameter from a sealed side towards an atmosphere side in the axial direction.

Abstract: A shock absorber has a suspension spring bearing fixed securely to a cylinder. The shock absorber includes a cylinder, a suspension spring bearing on the cylinder, and a suspension spring. A suspension spring bearing includes a cylindrical shaped main body that covers an end of the cylinder, an annular spring bearing part formed on a periphery of the main body, a plurality of upper salients that project inwardly from the main body and that are spaced apart at even intervals around the circumference of the main body, in which the upper salients press against the periphery of the cylinder, and a plurality of lower salients that project inwardly from the main body and that are spaced apart at even intervals around the circumference of the main body at locations below those of the upper salients, in which the lower salients press against the periphery of the cylinder.