To prevent noise in a hydraulic device wherein a delivery/suction port of an axial piston type hydraulic pump/motor and a delivery/suction port of a one-rod double-action type hydraulic cylinder are communicated with each other through an oil passage to constitute a hydraulic closed circuit, and a rotating shaft of the hydraulic pump/motor is connected to an output shaft of a motor so as to achieve driving and regeneration.
A hydraulic pump/motor 32 includes a valve plate 76 having a plurality of ports capable of being communicated with a cylinder block storing a plurality of pistons 78 arranged on the same circumference. A first port 51 communicated with a bottom oil chamber 35 of the hydraulic cylinder 16, a second port 52 communicated with a rod oil chamber 36, and two third ports 53F and 53R positioned on both sides on the circumference of the second port 52 and communicated with a hydraulic oil tank 9 are provided on the same circumference of the valve plate 76. A tapered cutout is provided on both ends in the circumferential direction of the first port, the second port and the third port.
YAMANAKA KEIJI
KOWADA NANAHIRO
| JP2009121435A | 2009-06-04 | |||
| JPS5725181U | 1982-02-09 | |||
| JPS63100679U | 1988-06-30 | |||
| JP2004003612A | 2004-01-08 |
| EP0935070A1 | 1999-08-11 |