Patent ID: 7409829
Filing Date: 2008-08-12
Classification: F04B,F16D,F16H

Abstract:
1. A pump unit including first and second hydraulic pumps and disposed away from first and second hydraulic motors with which the first and second hydraulic pumps are fluidly connected, comprising: a pump case enclosing the first and second hydraulic pumps and formed with an opening that has a size allowing the first and second hydraulic pumps to pass therethrough; and a center section detachably connected to the pump case so as to close the opening, wherein the center section on which the first and second hydraulic pumps are mounted forms a first pair of inlet/outlet passages that have first ends communicated with the first hydraulic pump and second ends opened to the outside of the center section to form connection ports connectable to the first hydraulic motor, a second pair of inlet/outlet passages that have first ends communicated with the second hydraulic pump and second ends opened to the outside of the center section at the same side as the connection ports of the first pair of inlet/outlet passages, a first bypass passage for communicating between the first pair of inlet/outlet passages, a first bypass valve that selectively communicates or shuts off the first bypass passage and has proximal end to be operated from the outside of the center section, a second bypass passage for communicating between the second pair of inlet/outlet passages, and a second bypass valve that selectively communicates or shuts off the second bypass passage and has proximal end to be operated from the outside of the center section.