# US 2009/0260516 A1 · Sealing structure for fluid pressure device

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- Number: US 2009/0260516 A1
- Document ID: US20090260516A1
- Status: Published application
- Kind: A1
- Application number: 12/439,599
- Filed: 2007-08-30
- Published: 2009-10-22
- Earliest claimed: 2006-09-04
- Assignees: SMC Corporation
- Inventors: Chiaki Fukui; Kazuyoshi Takahashi; Atsushi Tamai
- Web page: https://patentgrep.com/patent/US20090260516A1

## CPC

- F15B 15/1423: {Component parts; Constructional details}
- F15B 15/1419: {of non-circular cross-section}
- F15B 15/1442: {End cap sealings}
- F15B 15/1461: {Piston rod sealings}
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR

## Abstract

A sealing mechanism is mounted at an end section of a cylinder tube, which configures a cylinder device, by having a step section in between, and the sealing mechanism is sandwiched between the cylinder tube and a rod cover. The sealing mechanism includes a thin plate formed of a metal material, and a sealing member attached to one side surface of the plate. The plate and the sealing member are integrally arranged.

## Claims

### Claim 1

A seal structure for a fluid pressure device, in which a piston is displaced along a cylinder chamber under action of a pressure fluid supplied to the cylinder chamber of a cylinder tube, for maintaining airtightness of the cylinder chamber, comprising:
a seal member installed in an opening end of said cylinder tube, said seal member including:
a first seal element gripped between said cylinder tube and a cover member that closes said opening end; and
a second seal element surrounding an outer circumferential surface of a piston rod connected to said piston,
wherein said seal member is formed from an elastic material.

### Claim 2 (depends on 1)

The seal structure for a fluid pressure device according to claim 1, wherein said seal member is installed integrally on a base body formed in a plate shape, and is gripped together with said base body between said cover member and said cylinder tube.

### Claim 3 (depends on 2)

The seal structure for a fluid pressure device according to claim 2, wherein said first seal element is formed with a protrusion, which projects toward at least one of said cylinder tube and said cover member.

### Claim 4 (depends on 3)

The seal structure for a fluid pressure device according to claim 3, wherein said second seal element is formed with lips, which project toward and abut with an outer circumferential surface of said piston rod, such that when said piston rod is displaced, said lips always are in sliding contact with respect to said outer circumferential surface.

### Claim 5 (depends on 4)

The seal structure for a fluid pressure device according to claim 4, wherein said lips are formed from a first lip and a second lip separated a predetermined distance along a direction of displacement of said piston rod, and wherein said first and second lips extend while being inclined at predetermined angles in directions mutually separating from each other.

### Claim 6 (depends on 5)

The seal structure for a fluid pressure device according to claim 5, wherein said first lip is disposed on a side of said piston for maintaining airtightness between said piston rod and said cylinder tube, and said second lip is disposed on a side of said cover member for preventing dust or the like that adheres to said piston rod from penetrating into said cylinder tube.

### Claim 7 (depends on 5)

The seal structure for a fluid pressure device according to claim 5, wherein said seal member further comprises a guide member formed on a side of said cover member and adjacent to said second lip, said seal member being installed on said base body through said guide member.

### Claim 8 (depends on 7)

The seal structure for a fluid pressure device according to claim 7, wherein said seal member covers an end of said base body facing said piston rod, such that the end of said base body is covered by said first seal element, said second seal element and said guide member.

### Claim 9 (depends on 2)

The seal structure for a fluid pressure device according to claim 2, wherein a stepped portion recessed a predetermined depth is disposed on said opening end of said cylinder tube, said base body and said seal member being inserted into said stepped portion while being gripped by said cover member.

### Claim 10 (depends on 9)

The seal structure for a fluid pressure device according to claim 9, wherein said base body is formed in an elliptical shape in cross section corresponding to the opening end of said cylinder tube, and said seal member is formed in an elliptical shape in cross section covering an end surface and an inner circumferential region of said base body.