{
  "$type": "site.standard.document",
  "description": "According to an aspect of the present invention, there is provided a vehicle hydraulic master cylinder comprising; a bottomed cylinder hole having an annular seal groove; a cup seal fitted into the seal groove; and a concave-shaped plunger slidably inserted into the cylinder hole via the cup seal…",
  "path": "/patents/999313",
  "publishedAt": "2012-08-15T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B60T11/165",
    "NISSIN KOGYO KK [JP]"
  ],
  "textContent": "According to an aspect of the present invention, there is provided a vehicle hydraulic master cylinder comprising; a bottomed cylinder hole having an annular seal groove; a cup seal fitted into the seal groove; and a concave-shaped plunger slidably inserted into the cylinder hole via the cup seal (11), the seal groove comprising: a seal groove bottom surface (13a) extended along a circumferential direction of the cylinder hole; a cylinder hole bottom-side surface (13b); and a cylinder hole opening-side surface (13c), the cup seal comprising; a base portion (11a) at the cylinder hole opening side; an inner peripheral lip portion (11b) that extends toward the cylinder hole bottom side from the base portion to slide along an outer peripheral surface of the plunger; and an outer peripheral lip portion (11c) that extends toward the cylinder hole bottom side from the base portion to abut against the seal groove bottom surface, wherein the seal groove further comprises a chamfered region (13g) formed by chamfering a radial inner region of the cylinder hole opening-side surface, wherein the cup seal further comprises an elastic protrusive piece (11d) protruded from the inner peripheral lip portion to abut against the cylinder hole bottom-side surface, and a contact pressure adjustment surface (11g) formed at a radial inner region of the base portion, and wherein, at the time of non-operation, a starting point of the contact pressure adjustment surface and a starting point of the chamfered region are located outwardly of a tip abutment point of the elastic protrusive piece against the cylinder hole bottom-side surface.",
  "title": "Vehicle hydraulic master cylinder and method of forming a seal groove therein"
}