| 摘要 |
PURPOSE:To reduce the load of a pump to decrease driving force by connecting a drain passage for operating liquid of a variable displacement pump to an intake passage. CONSTITUTION:A variable displacement pump 10 is provided with a pump body 12 of a radial piston type and a discharge quantity control valve 14. Plungers 24, 26 are fitted to a cam shaft 18 slidably. Operating liquid is entered from an operating liquid introducting chamber 36 via openings 24a, 26a to the plungers and is passed through liquid chambers 42, 44 via check valves 46, 48 to be supplied to supply passages 50, 52. Operating liquid discharged from a large displacement pump PL, and a small displacement Ps is passed via the discharge quantity control valve 14 to a drain passage 76 and then is passed to an intake passage 37 for connecting an operating liquid supply chamber 36 to a reservoir tank. Consequently, the load of the pump is reduced and small driving force becomes enough. |
