| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a hydraulic power unit miniaturized while ensuring the necessary performance of a spring for allowing a switching valve to be constantly abutted on a switching valve engagement member. SOLUTION: A first valve hole 53 and a second valve hole 54 are formed on a cylinder block 25 with an input shaft 15 inserted therein, and a first switching valve 56 and a second switching valve 66 are mounted in the first and second valve holes. A pressuring chamber 53a is formed on the right of the first valve hole 53, and a pressurizing chamber 54a is formed on the left of the second valve hole 54. Coil springs 57 and 67 are mounted in the pressuring chambers 53a and 54a. An oil passage 74, an oil passage 73 and a circumferential groove 72 are formed on a case 11, an introductory oil passage 71, a shaft hole 70 and an oil passage 77 are formed on the input shaft 15, and a circumferential groove 78 is formed on the cylinder block 25. The hydraulic oil flows into the oil passage 74 from a charging pump to fill the pressurizing chambers 53a and 54a with the hydraulic oil. The switching valves 56 and 66 are energized by the oil pressure of the hydraulic oil in the pressurizing chamber 53a and 54a and the coil springs 57 and 67.</p> |
