| US 7,500,361 B2 | ||
| Hydraulic pump unit and working vehicle | ||
| Ryota Ohashi, Hyogo (Japan) | ||
| Assigned to Kanzaki Kokyukoki Mfg. Co., Ltd., Hyogo (Japan) | ||
| Filed on Feb. 08, 2006, as Appl. No. 11/349,238. | ||
| Claims priority of application No. 2005-117006 (JP), filed on Apr. 14, 2005. | ||
| Prior Publication US 2006/0242956 A1, Nov. 02, 2006 | ||
| Int. Cl. F16D 31/02 (2006.01); F16D 39/00 (2006.01); G05G 9/047 (2006.01) | ||
| U.S. Cl. 60—444 [60/488] | 7 Claims |
| 1. A hydraulic pump unit of variable displacement type disposed away from a pair of hydraulic motor units which are capable
of being independently arranged, the pump unit fluidly-connected to the pair of hydraulic motor units so as to change the
outputs of the pair of hydraulic motor units in both forward and reverse rotation directions, comprising:
a pair of first and second hydraulic pump bodies operatively rotated and driven by a driving source,
a pump case surrounding the first and second hydraulic pump bodies,
a pair of first and second capacity adjusting mechanisms for respectively changing capacities of the first and second hydraulic
pump bodies, and
a hydraulic servomechanism for transmitting an external input based on a manual operation to the first and second capacity
adjusting mechanisms by utilizing a hydraulic force, wherein
each of the first and second capacity adjusting mechanisms includes an output adjusting member for changing a reciprocating
range of hydraulic pistons of the corresponding hydraulic pump body according to its tilting position, and a control shaft
having a base end portion operatively connected to the output adjusting member so as to tilt the output adjusting member and
a tip end portion accessible from outside of the pump case, the hydraulic servomechanism includes a servo piston case defining
first and second piston accommodating chambers; first and second servo pistons respectively accommodated in a reciprocating
manner in the first and second piston accommodating chambers, each of the first and second servo pistons dividing the corresponding
piston accommodating chamber into a regular rotation oil chamber and a reverse rotation oil chamber; and first and second
directional switching valves for changing corresponding passages fluidly connected to the corresponding regular rotation oil
chambers and the corresponding reverse rotation oil chambers according to the external input,
each of the first and second servo pistons is formed with an engaging groove on its outer peripheral surface, the engaging
groove extending in a direction orthogonal to an axis line of the servo piston,
the tip ends of the control shafts of the first and second capacity adjusting mechanisms extend outward from one end surface
of the pump case, and
the servo piston case is detachably connected to the one end surface of the pump case so that the tip ends of the control
shafts of the first and second capacity adjusting mechanisms are operatively engaged into the engaging grooves of the first
and second servo pistons, respectively.
|