Patent ID: 7371055

Claim:
A pump unit for supplying oil to first and second hydraulic motors respectively connected to left and right drive wheels, comprising: a first hydraulic pump which includes a first pump shaft with first and second ends and which is fluidly connected to the first hydraulic motor through a first closed circuit; a second hydraulic pump which includes a second pump shaft with first and second ends and which is fluidly connected to the second hydraulic motor through a second closed circuit; a charge pump for replenishing oil into the first and second closed circuits; a first housing which has an opening for accommodating the first hydraulic pump and which supports the first end of the first pump shaft, the opening facing in a direction along an axis line of the first pump shaft and having a size for allowing the first hydraulic pump to be passed therethrough; a second housing which has an opening for accommodating the second hydraulic pump and which supports the second end of the second pump shaft, the opening facing in a direction along an axis line of the second pump shaft and having a size for allowing the second hydraulic pump to be passed therethrough; a common center section which has a first side closing the opening of the first housing and supporting the second end of the first pump shaft, a second side closing the opening of the second housing and supporting the first end of the second pump shaft, the second side being opposite to the first side, a hole penetrating between the first and second sides, the common center section including a charge passage; and a coupler which is accommodated within the hole and which operatively connects the second end of the first pump shaft and the first end of the second pump shaft; wherein the first end of the first pump shaft extends outwards from the first housing to be operatively connected to a power source; the charge pump is mounted to the second housing; the second end of the second pump shaft extends outwards from the second housing to drive the charge pump; and the second housing is provided with a passage for introducing pressurized oil from the charge pump into the charge passage.