| 摘要 |
<p>PURPOSE:To prevent bite-in of a sealing member, when the piston slides in a tapered cylinder hole, by interposing a backup ring deformable elastically in the circumferential and radial directions between the sealing member and piston. CONSTITUTION:A piston 3 to be inserted in a tapered cylinder hole 2 slidably is equipped with a sealing member 5, fitted in a groove, and furnish with a backup ring 8 interposed between this sealing member 5 and a step in the abovementioned groove. The backup ring 8 is made of a material elastically deformable, and a tapered cylinder 10 having minor diameter end at the disc-shaped part 9 is projecting from this ring 8. A slit 11 is excavated in this ring 8. When the backup ring 8 is fitted on the piston 3, the abovementioned cylindrical part 10 forms a gap 12 to facilitate elastic deformation. At the time of piston 3 moving forward, the outside circumference of the disc-shaped part 9 of the backup ring 8 is in contact with the internal surface of the cylinder hole and slides in elastic deformation. Provision of a groove 14 at the end of the cylindrical part 10 assures even elastic deformation.</p> |
