| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a plunger type hydraulic pump capable of effectively heightening the pumping efficiency while a driving means for pump plunger is constructed small. SOLUTION: A pump housing 30 is equipped with a stepped cylinder hole 32 consisting of a first hole portion 321, a second hole portion 322 having a greater diameter than the first 321, and a third hole portion 323 having a smaller diameter than the second 322 which are positioned coaxially one over another, and the first, second, third plunger portions 341-343 of a pump plunger 34 are fitted in these cylinder hole portions 321-323, and a pump chamber 35 confronted by the front face of the first plunger portion 341 is formed in the first hole portion 321 while a suction chamber 36 and filling chamber 37 confronted by the front and rear faces of the second plunger portion 342 are partitioned in the second hole portion 322, and between the suction chamber 36 and filling chamber 37, a one-way valve 51 is installed to admit flowing of a working oil from the suction chamber 36 to the filling chamber 37, which 37 is put in communication with the pump chamber 25 through a suction valve 55.</p> |
