Hydraulic piston pump unit with integral fluid reservoir

Abstract

Single and dual hydraulic piston pump units comprising at least one pump unit including a variable displacement axial piston main pump rotatably journalled within an at least one pump housing, and operatively interconnected for dual pump units, the pump housing(s) being of a size having an integral fluid reservoir for the at least one pump unit, the reservoir including a drain port and plug and the housing including an air venting device. A block portion includes at least one pair of reversible fluid inlet and outlet ports and a fluid filter connecting portion. At least one center through shaft drives the main pump(s), the charge pump, and a cooling fan. A single pump unit in combination with a rotatable electric motor comprises a portable hydraulic power-producing unit. A dual pump unit in combination with a vehicle, having independently hydraulic motor-driven left and right wheels, permits independent wheel propulsion thereof.

1 . A variable displacement hydraulic piston pump unit comprising in combination: 
 a. one of an over-center axial piston main pump, a bent axis piston main pump, and a radial piston main pump;    b. said main pump being rotatably journalled within a pump unit housing, said housing being of a size sufficient to include an internal volume portion that serves as an integral fluid reservoir for said pump unit.    
   
   
       2 . The piston pump unit of  claim 1 , wherein said pump unit housing further includes an air venting device.  
   
   
       3 . The piston pump unit of  claim 2 , wherein said fluid reservoir includes a case drain port.  
   
   
       4 . The piston pump unit of  claim 1 , wherein said fluid reservoir includes a case drain port.  
   
   
       5 . The piston pump unit of  claim 1  further including a block portion operatively interconnected with and having one end thereof physically adjoining one end of said pump unit housing, said block portion further including a pair of reversible hydraulic fluid inlet and outlet ports.  
   
   
       6 . The piston pump unit of  claim 5 , wherein said pump unit housing further includes an air venting device.  
   
   
       7 . The piston pump unit of  claim 5 , wherein said fluid reservoir includes a case drain port.  
   
   
       8 . The piston pump unit of  claim 7 , wherein said pump unit housing further includes an air venting device.  
   
   
       9 . The piston pump unit of  claim 5 , wherein said block portion includes an internal recess portion.  
   
   
       10 . The piston pump of  claim 9  further including a hydraulic fluid filter, said filter being located within said center block internal recess portion.  
   
   
       11 . The piston pump unit of  claim 5  further including an axial center through shaft, said through shaft extending axially through said main pump housing, said main pump and said block portion, said through shaft including an input portion, extending from another end of said pump unit housing remote from said block portion, said through shaft further including another portion, extending from another end of said block portion remote from said pump housing, with said through shaft driving said main pump.  
   
   
       12 . The piston pump unit of  claim 11  further including a charge pump, said charge pump having one end thereof adjoining said another end of said block portion, said charge pump being operatively interconnected with said block portion and driven by said another portion of said through shaft.  
   
   
       13 . The piston pump unit of  claim 12  further including a cooling fan, said cooling fan being axially spaced from another end of said charge pump, remote from said block portion, and driven by said another portion of said through shaft.  
   
   
       14 . The piston pump unit of  claim 11  further including a cooling fan, said cooling fan being axially spaced from said another end of said block portion and driven by said another portion of said through shaft.  
   
   
       15 . The piston pump unit of  claim 11  in combination with a prime mover, said prime mover being operatively connected with said input portion of said through shaft for driving said through shaft and consequently said main pump; said pump unit, in combination with said prime mover, comprising a portable hydraulic power-producing unit.  
   
   
       16 . The piston pump unit of  claim 12  in combination with a prime mover, the latter being operatively interconnected with said through shaft for driving said main pump and said charge pump; said pump unit, in combination with said prime mover, comprising a portable hydraulic power-producing unit.  
   
   
       17 . The piston pump unit of  claim 13  in combination with a prime mover, the latter being operatively interconnected with said input portion of said through shaft for driving said main pump, said charge pump and said cooling fan; said pump unit, in combination with said prime mover, comprising a portable hydraulic power-producing unit.  
   
   
       18 . The piston pump unit of  claim 5  further including a hydraulic fluid filter in operative combination with said block portion.  
   
   
       19 . The piston pump unit of  claim 18 , wherein said hydraulic fluid filter is of the spin-on cartridge type.  
   
   
       20 . A dual variable displacement hydraulic piston pump unit comprising in combination: 
 a. a first pump unit including a variable displacement axial piston main pump rotatably journalled within a first pump unit housing, said first main pump adjoining    b. a second pump unit including a variable displacement axial piston pump rotatably journalled within a second pump unit housing;    c. said first and second pump unit housings being operatively interconnected and of a size having an internal volume portion sufficient to serve as an integral hydraulic fluid reservoir for said first and second pump units.    
   
   
       21 . The dual piston pump unit of  claim 20 , wherein at least one of said pump unit housings includes an air venting device.  
   
   
       22 . The dual piston pump unit of  claim 21 , wherein said fluid reservoir includes a case drain port.  
   
   
       23 . The dual piston pump unit of  claim 20 , wherein said fluid reservoir includes a case drain port.  
   
   
       24 . The dual piston pump unit of  claim 20  further including a center block portion operatively interconnected, on each opposed axial end, with an adjoining first end of each of said first and second pump unit housings, said center block portion including a pair of independent reversible hydraulic fluid inlet and outlet ports for each of said first and second pump units.  
   
   
       25 . The dual piston pump unit of  claim 24 , wherein at least one of said pump unit housings includes an air venting device.  
   
   
       26 . The dual piston pump unit of  claim 24 , wherein said fluid reservoir includes a case drain port.  
   
   
       27 . The dual piston pump unit of  claim 26 , wherein at least one of said pump unit housings includes an air venting device.  
   
   
       28 . The dual piston pump unit of  claim 24 , wherein said center block portion includes an internal recess portion.  
   
   
       29 . The dual piston pump unit of  claim 28  further including a hydraulic fluid filter, said filter being located within said center block internal recess portion.  
   
   
       30 . The dual piston pump unit of  claim 24 , wherein said first and second pump units further include a respective first and second axial center through shaft, said first and second through shafts extending axially through their respective main pump housing, main pump and block portion; one of said first and second through shafts including an input portion, extending from a first another side of its respective pump unit housing remote from said center block portion; another of said first and second through shafts including another portion, extending from a second another side of its respective pump housing remote from said center block portion, with said first and second through shafts driving their respective main pumps.  
   
   
       31 . The dual piston pump unit of  claim 30 , wherein each of said first and second axial center through shafts further includes an inner end portion, said inner end portions extending into and operatively interconnecting with each other within said center block portion.  
   
   
       32 . The dual piston pump unit of  claim 30  further including a charge pump, said charge pump having one end adjoining said second another side of said respective pump housing, said charge pump being driven by said another portion of one of said first and second through shafts.  
   
   
       33 . The dual piston pump unit of  claim 32  further including a cooling fan, said cooling fan being axially spaced from another end of said charge pump, said cooling fan being driven by said another portion of one of said first and second through shafts.  
   
   
       34 . The dual piston pump unit of  claim 20 , wherein said first and second pump units are arranged in an inline configuration.  
   
   
       35 . The dual piston pump unit of  claim 34 , wherein said inline configuration is in a back-to-back arrangement.  
   
   
       36 . The dual piston pump unit of  claim 24 , wherein said first and second pump units are arranged in an inline back-to-back configuration, with said center block portion being interposed therebetween.  
   
   
       37 . The dual piston pump unit of  claim 20 , wherein said first and second pump units are arranged in a side-by-side configuration.  
   
   
       38 . The dual piston pump unit of  claim 20 , wherein said first and second pump units are angularly offset relative to each other.  
   
   
       39 . The dual piston pump unit of  claim 38 , wherein said angular offset occurs in at least one plane.  
   
   
       40 . In a vehicle, including a right side wheel, driven by a right side hydraulic motor, and a left side wheel, driven by a left side hydraulic motor, the dual piston pump unit of  claim 31 , in combination with a prime mover, said prime mover being operatively connected with said input portion of one of said first and second through shafts for driving said first and second through shafts for consequently driving said first and second main pumps; said first pump unit being operatively connected with one of said right and left side hydraulic motors and said second pump unit being operatively interconnected with the other of said right and left side hydraulic motors, thereby permitting independent propulsion of said right and left side wheels.  
   
   
       41 . In a vehicle, including a right side wheel, powered by a right side hydraulic motor, and a left side wheel, powered by a left side hydraulic motor, the dual pump unit of  claim 32 , in combination with a prime mover, said prime mover being operatively connected with said input portion of one of said first and second through shafts for driving said first and second main pumps and said charge pump; said first pump unit being operatively connected with one of said right and left side hydraulic motors and said second pump unit being operatively connected with the other of said right and left hydraulic motors, thereby permitting independent rotational movement of said right and left side wheels.  
   
   
       42 . In a vehicle, including a right side wheel, rotatable via a right side hydraulic motor, and a left side wheel, rotatable via a left side hydraulic motor, the dual pump unit of  claim 33 , in combination with a prime mover, the latter being operatively interconnected with said input portion of one of said first and second through shafts for driving said first and second main pumps together with said charge pump and said cooling fan; said first pump unit being operatively connected with one of said right and left side hydraulic motors and said second pump being operatively connected with the other of said right and left hydraulic motors, thereby permitting independent angular movement of said right and left side wheels.  
   
   
       43 . The dual piston pump unit of  claim 42  further including a hydraulic fluid filter in operative combination with said center block portion.  
   
   
       44 . The dual piston pump unit of  claim 43 , wherein said hydraulic fluid filter is of the spin-on cartridge type.  
   
   
       45 . The vehicle of  claim 42 , wherein said vehicle is a zero turn radius mowing machine.