To provide a hydraulic device reducing friction and smoothing slide between a plunger and a plunger hole provided in a cylinder block, and preventing eccentricity of the plunger in the plunger hole.
The hydraulic device is provided with grooves 8d, 10d, 31a, 31b, 41a, 41b or the like in parallel with an opening surface of the cylinder block 7 on a surface on which the plungers 8, 10 and the plunger holes 31, 42 are butted. The position where the grooves or the like are provided is either of a position which gets closest to an opening surface of the cylinder block 7 at an extension side dead center of the plungers in butting parts of side surfaces of the plungers 8, 10 and the plunger holes 31, 41, or a position which gets farthest from the opening surface of the cylinder block 7 at an extension side dead center of the plungers 8, 10 in parts near the opening surface of the cylinder block 7 on an inner surface of the plunger holes 31, 41 and the butting parts of the plungers 8, 10 and inner surfaces of the plunger holes 31, 41.
EGUCHI SHINGO
SHIOZAKI SHUJI
| JP2004239077A | 2004-08-26 | |||
| JPS6128768A | 1986-02-08 |
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