Kobe Steel, Ltd.

Shunsuke Morinaka

Toru Okada

Tomohiro Otsuka

In a piston including a plurality of piston rings, a state where a difference in differential pressure between the piston rings is eased is maintained even after passage of time, and the life of the piston rings is extended. A piston includes a piston body in which a plurality of ring grooves is formed, and a plurality of piston rings respectively arranged in the ring grooves. In the piston, a leakage groove is formed on a low-pressure side surface of the ring groove, and in a state where the piston ring is abutted with the low-pressure side surface while being abutted with a cylinder, the leakage groove ensures communication between a high-pressure side space and a low-pressure side space with respect to the piston ring.

Piston and reciprocating compressor

A labyrinth seal includes a step portion, a high-puressure-side fin, a low-puressure-side fin and an annular groove. The step portion is formed in a portion of a second member on one side of the facing direction and faces a high-pressure side. The high-pressure-side fin is arranged on a high-pressure side relative to the step portion. The low-pressure-side fin is arranged on a low-pressure side relative to the step portion. The annular groove is formed in a portion of the second member on the one side of the facing direction and is arranged in at least a part of a region on the low-pressure side relative to the step portion as well as on the high-pressure side relative to the low-pressure-side fin.

Labyrinth seal

A labyrinth seal includes a step portion formed on an outer circumferential portion of a rotary body, a fin extending radially inward from an inner circumferential portion of a stationary body, and an annular groove formed in the outer circumferential portion of the rotary body. The step portion includes a diameter-increasing step portion and a diameter-decreasing step portion. The fin includes a first fin, a second fin, and a third fin. The annular groove is disposed in at least a part of a region that is located close to the low-pressure side compared to the high-pressure-side step portion and close to the high-pressure side compared to the third fin.

A labyrinth seal is included in a rotary machine. The rotary machine includes a first member, a second member facing the first member, and a gap formed between the first member and the second member. The labyrinth seal includes a step portion, a high-pressure-side fin on the high-pressure side relative to the step portion, a low-pressure-side fin on the low-pressure side relative to the step portion, and an annular groove. The step portion is configured to allow a portion of the second member on the low-pressure side relative to be arranged closer to the other side of the facing direction than a portion of the second member on the high-pressure side. The annular groove is arranged in at least a part of a region on the low-pressure side and on the high-pressure side, relative to the low-pressure-side fin.

A labyrinth seal includes a step-up structure step portion which is a step portion on a high-pressure side, a step-down structure step portion which is a step portion which is a step portion on a low-pressure side, a fin and an annular groove. The fin is arranged on the low-pressure side relative to the step-down structure step portion. The annular groove is arranged in at least a part of a region on the low-pressure side relative to the step-up structure step portion as well as on the high-pressure side relative to the third fin.

A labyrinth seal suppresses leakage of fluid through a gap between a circumferential outer surface of a rotating body, having an axis of rotation, and a circumferential inner surface of a stationary body provided on an outer side of the rotating body, by increasing fluid energy loss caused by vortices. Said leakage occurs in an axial direction from a high pressure to a low pressure side. A step is formed on the outer surface such that the diameter of the low pressure side is smaller than that of the high pressure side. A fin extending radially inward from the inner surface is formed on at least the low pressure side of the step. An annular groove is formed to extend in a circumferential direction in the outer surface, in at least one portion of the area axially between the step and the fin.

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Hyogo, Japan

Shunsuke Morinaka