Tandem pump unit

A tandem pump unit comprising:

• the integral arrangement of a first hydraulic pump and a second hydraulic pump;
• said first hydraulic pump with a first pump shaft, adapted to be connected to a first actuator via a first pair of hydraulic lines;
• said second hydraulic pump with a second pump shaft, adapted to be connected to a second actuator via a second pair of hydraulic lines;
• wherein said first pump shaft and said second pump shaft respectively having adjacent ends connected together so that said first and second pump shafts are coaxially aligned and non-rotatably connected in tandem;
• a charge line disposed within said tandem pump unit and having a first end communicating with either a reservoir or a hydraulic fluid feeding mechanism and a second end adapted to communicate with the first pair of hydraulic lines and the second pair of hydraulic lines, respectively.

A tandem pump unit comprising:

• the integral arrangement of a first hydraulic pump and a second hydraulic pump;
• said first hydraulic pump with a first pump shaft, adapted to be connected to a first actuator via a first pair of hydraulic lines;
• said second hydraulic pump with a second pump shaft, adapted to be connected to a second actuator via a second pair of hydraulic lines;
• wherein said first pump shaft and said second pump shaft respectively having adjacent ends connected together so that said first and second pump shafts are coaxially aligned and non-rotatably connected in tandem;
• a center section supporting said first hydraulic pump and said second hydraulic pump;
• a housing accommodating said first hydraulic pump and said second hydraulic pump;
• wherein said first hydraulic pump, said second hydraulic pump, said center section and said housing are integrally connected together to constitute a single unit;
• and
• a reservoir tank supportedly connected to said single unit for storing hydraulic fluid to be replenished to said first pair of hydraulic lines and said second pair of hydraulic lines.

A tandem pump unit comprising:

• a first hydraulic pump and a second hydraulic pump respectively having a first pump shaft and a second pump shaft that are coaxially aligned and non-rotatably connected in tandem;
• a center section supporting said first hydraulic pump and said second hydraulic pump;
• a housing accommodating said first hydraulic pump and said second hydraulic pump, said housing adapted to be used as a hydraulic fluid tank;
• a hydraulic fluid circulation mechanism for taking the hydraulic fluid from the hydraulic tank, and again returning the same to said hydraulic tank;
• and
• said hydraulic fluid circulation mechanism designed to cool the hydraulic fluid while circulating the same.

A tandem pump unit comprising:

• a first hydraulic pump including a first pump shaft with a first end and a second end;
• a second hydraulic pump including a second pump shaft with a first and a second end, said second pump shaft being aligned coaxially with the first pump shaft;
• a coupler for operatively connecting the first pump shaft and the second pump shaft together with the first ends thereof;
• housing means forming opening means through which the first and second pumps are incorporated with said housings means;
• center section means disposed so as to over said opening means of the housing means and in cooperation with said housing means form a first hydraulic pump accommodation space and a second hydraulic pump accommodation space, which respectively accommodate the first and second hydraulic pumps;
• said center section means having surfaces respectively facing the first and second hydraulic pump accommodation spaces for supporting thereon the first and second hydraulic pumps, said center section means being provided with a first pair of inlet/outlet ports for the first hydraulic pump, a second pair of inlet/outlet ports fo the second hydraulic pump, said first and second pairs of inlet/outlet ports being respectively open to the outside through said surfaces, and first and second hydraulic lines for respectively providing fluid connections between said first and second pairs of inlet/outlet ports;
• a power input portion provided at any one of the second ends of the first and second pump shafts;
• and
• a charge pump operatively connected with any one of the second ends of the first and second pump shafts for feeding pressurized hydraulic fluid to the first and second hydraulic lines, respectively.

A tandem pump unit comprising:

• a first hydraulic pump including first pump shaft with a first end and a second end;
• a second hydraulic pump including a second pump shaft with a first and a second end, said second pump shaft being aligned coaxially with the first pump shaft;
• a coupler for operatively connecting the first pump shaft and the second pump shaft together via the first ends thereof;
• a housing having openings respectively formed at opposite ends of said housing with respect to a pump shaft direction for respectively incorporating the first and second pumps with the housing therethrough, and a bearing wall located substantially at the center of the pump shaft direction, said bearing wall forming a through hole, through which said coupler is inserted;
• first and second center sections connected with said housing so as to respectively cover said openings of the housing and in cooperation with said housing form at first hydraulic pump accommodation space and a second hydraulic pump accommodation space, which respectively accommodate the first and second hydraulic pumps;
• said first and second center sections restively having surfaces respectively facing the first and second hydraulic pump accommodation spaces for supporting thereon the first and second hydraulic pumps, said first and second center sections being respectively provided with a first pair of inlet/outlet ports for the first hydraulic pump and a second pair of inlet/outlet ports for the second hydraulic pump, said first and second pairs of inlet/outlet ports being respectively open to the outside through said surfaces, and first and second hydraulic lines for respectively providing fluid connections between said first and second pairs of inlet/outlet ports;
• a power input portion provided at any one of the second ends of the first and second pump shafts;
• and
• a charge pump mounted on a surface of any one of the first and second center sections, which surface faces outside of the first and second center sections, so as to be operatively connected with any one of the second ends of the first and second pump shafts for feeding pressurized hydraulic fluid to the first and second hydraulic lines, respectively.

A tandem pump unit comprising:

• a first hydraulic pump including a first pump shaft with a first end and a second end;
• a second hydraulic pump including a second pump shaft with a first and a second end, said second pump shaft being aligned coaxially wit the first pump shaft;
• a coupler for operatively connecting the first pump shaft and the second pump shaft together via the first ends thereof;
• a first housing having an opening formed at one end of the first housing with respect to a pump shaft direction for incorporating the first pump with the first housing therethrough;
• a second housing having an opening formed at opposite end of the housing with respect to a pump shaft direction for incorporating the second pump with the second housing therethrough;
• a center section interposed between the one end of the first housing and the opposite end of the second housing so as to cover said openings of the first and second housings and connected with the first and second housings, and in cooperation with said first and second housings form a first hydraulic pump accommodation space and a second hydraulic pump accommodation space, which respectively accommodate the first and second hydraulic pumps;
• said center section having surfaces respectively facing the first and second hydraulic pump accommodation spaces for supporting thereon the first and second hydraulic pumps, said center section being provided with a first pair of inlet/outlet ports for the first hydraulic pump, a second pair of inlet/outlet ports for the second hydraulic pump, said first and second pairs of inlet/outlet ports being respectively open to the outside through said surfaces, and first and second hydraulic lines for respectively providing fluid connections between said first and second pairs of inlet/outlet ports, said center section forming a through hole, through which said coupler is inserted;
• a power input portion provided at any one of the second ends of the first and second pump shafts;
• and
• a charge pump mounted on a surface of any one of the first and second housings, which surface faces outside of the first and second center housings, so as to be operatively connected with any one of the second ends of the first and second pump shafts for feeding pressurized hydraulic fluid to the first and second hydraulic lines, respectively.

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 fist pump shaft operatively connected to a power source and which is fluidly connected to said first hydraulic motor through a first closed circuit;
• a second hydraulic pump which includes a second pump shaft operatively connected to said first pump shaft and which is fluidly connected to said second hydraulic motor through a second closed circuit;
• a housing for accommodating said first and second hydraulic pumps;
• and
• a common charge pump which is driven by said second pump shaft and which supplies pressure oil to both said first and second closed circuit.

A pump unit comprising:

• a hydraulic pump having a pump shaft operatively connected to a power source;
• a housing for accommodating said hydraulic pump;
• and
• a charge pump which is connected to said housing and which is driven by said pump shaft, wherein both ends of said pump shaft extend outward from said housing and said charge pump, and
• the first and second ends of said pump shaft respectively support a pulley and a cooling fan.