Dual flow axial piston pump

Abstract

A pump for a machine hydraulic system is disclosed. The pump has a housing, a first plurality of pumping elements, and a second plurality of pumping elements. The housing has a central bore with a first end and a second end. The housing also has a first high pressure port for fluid communication with a first external circuit and a second high pressure port for fluid communication with a second external circuit. The first plurality of pumping elements is disposed within the housing and is in fluid communication with the first high pressure port. The second plurality of pumping elements is disposed with the housing, axially aligned in opposition to the first plurality of pumping elements, and is in fluid communication with the second high pressure port.

1 . A pump, comprising: 
 a housing having: 
 a central bore with a first end and a second end;  
 a first high pressure port for fluid communication with a first external circuit; and  
 a second high pressure port for fluid communication with a second external circuit;  
   a first plurality of pumping elements disposed within the housing and being in fluid communication with the first high pressure port; and    a second plurality of pumping elements disposed with the housing, axially aligned in opposition to the first plurality of pumping elements, and being in fluid communication with the second high pressure port.    
   
   
       2 . The pump of  claim 1 , further including: 
 a shaft rotatably disposed within the housing and having an axial direction; and    a rotor fixedly connected to the shaft and having a first face and an opposing second face, wherein:    the first plurality of pumping elements includes: 
 a first plurality of piston members extending from the first face; and  
 a first plurality of cylinders located within the first end of the central bore to receive the first plurality of piston members; and  
   the second plurality of pumping elements includes: 
 a second plurality of piston members extending from the second face; and  
 a second plurality of cylinders located within the second end of the central bore to receive the second plurality of piston members.  
   
   
   
       3 . The pump of  claim 2 , wherein the housing further includes a low pressure port in communication with an external supply of fluid and both of the first and second pluralities of cylinders.  
   
   
       4 . The pump of  claim 2 , wherein the housing further includes: 
 a first low pressure port in fluid communication with an external supply of fluid and the first plurality of cylinders; and    a second low pressure port in fluid communication with the external supply of fluid and the second plurality of cylinders.    
   
   
       5 . The pump of  claim 2 , wherein the first and second plurality of piston members are fixedly connected to the rotor.  
   
   
       6 . The pump of  claim 2 , further including: 
 a first drum plate operatively connected to the first plurality cylinders; and    a second drum plate operatively connected to the second plurality of cylinders.    
   
   
       7 . The pump of  claim 6 , wherein the first and second drum plates are tilted at an angle relative to the axial direction.  
   
   
       8 . The pump of  claim 7 , wherein the first drum plate is fixed at a different angle than the second drum plate to pressurized the fluid flowing from the first high pressure port to a different level relative to the fluid flowing from the second high pressure port.  
   
   
       9 . The pump of  claim 7 , wherein the tilt angle is variable during operation of the pump to vary a pressure of fluid exiting the first and second high pressure ports.  
   
   
       10 . The pump of  claim 9 , wherein the tilt angle of first drum plate is separately and simultaneously variable relative to the tilt angle of the second drum plate.  
   
   
       11 . The pump of  claim 2 , wherein the first and second plurality of piston members are substantially aligned with the axial direction.  
   
   
       12 . A method of pressurizing dual streams of fluid, comprising: 
 directing low pressure fluid through at least one port into a housing to separate axial ends of the housing;    working the fluid at a first end of the housing in an axial direction of the housing to pressurize the fluid;    working the fluid at a second end of the housing in an axial direction of the housing to pressurize the fluid;    expelling pressurized fluid from the first end of the housing through a high pressure port to a first external circuit; and    simultaneously expelling pressurized fluid from the second end of the housing through a high pressure port to a second external circuit.    
   
   
       13 . The method of  claim 12 , wherein directing low pressure fluid through at least one port includes directing low pressure fluid through a first port to the first end of the housing and directing low pressure fluid through a second port to the second end of the housing.  
   
   
       14 . The method of  claim 12 , further including distributing the fluid from the at least one port to a plurality of axial pumping elements located with the first end of the housing and to a plurality of axial pumping elements located within the second end of the housing.  
   
   
       15 . The method of  claim 14 , further including varying a displacement of the first and second plurality of pumping elements.  
   
   
       16 . The method of  claim 15 , wherein varying a displacement includes varying a displacement of the first plurality of pumping elements differently than the displacement of the second plurality of pumping elements.  
   
   
       17 . A machine, comprising: 
 a first hydraulic circuit;    a second hydraulic circuit; and    a pump configured to supply separate streams of pressurized fluid to the first and second hydraulic circuits, the pump including: 
 a housing having: 
 a central bore with a first end and a second end;  
 a first high pressure port in fluid communication with the first external circuit;  
 a second high pressure port in fluid communication with the second external circuit; and  
 at least one low pressure port in communication with an external supply of fluid;  
 
 a shaft rotatably disposed within the housing and having an axial direction;  
 a rotor fixedly connected to the shaft and having a first face and an opposing second face;  
 a first plurality of piston members extending from the first face;  
 a first plurality of cylinders located within the first end of the central bore to receive the first plurality of piston members and being in fluid communication with the at least one low pressure port;  
 a second plurality of piston members extending from the second face;  
 a second plurality of cylinders located within the second end of the central bore to receive the second plurality of piston members and being in fluid communication with the at least one low pressure port.  
   
   
   
       18 . The machine of  claim 17 , wherein: 
 the at least one low pressure port is a first low pressure port in fluid communication with the first plurality of cylinders; and    the housing further includes a second low pressure port in fluid communication with the external supply of fluid and the second plurality of cylinders.    
   
   
       19 . The machine of  claim 17 , further including: 
 a first drum plate operatively connected to the first plurality cylinders; and    a second drum plate operatively connected to the second plurality of cylinders,    wherein the first drum plate is fixed at a different angle relative to the axial direction than the second drum plate to pressurized the fluid flowing from the first high pressure port to a different level relative to the fluid flowing from the second high pressure port.    
   
   
       20 . The machine of  claim 17 , further including: 
 a first drum plate operatively connected to the first plurality cylinders; and    a second drum plate operatively connected to the second plurality of cylinders,    wherein a tilt angle of the first drum plate is separately and simultaneously variable relative to a tilt angle of the second drum plate to vary a pressure of fluid exiting the first and second high pressure ports.