Axial piston hydraulic power unit with pseudo slippers

Abstract

A combination of a bull nose type and slipper type axial piston pumps. The pseudo slipper axial piston pump has an elongated piston body with a bore disposed therethrough. The bore has a spring within to create a hold down mechanism. Swivelably connected to the piston body is a pseudo slipper that engages an anti-frictional thrust bearing having first and second race elements in parallel relation with a bearing element therebetween. The anti-frictional thrust bearing then controls the angle of the swashplate.

1 . An axial piston pump having pseudo slippers comprising: at least one elongated piston that is disposed within the pump; 
 said piston having a spring attached thereto to create pressure on the slippers;    said slippers swivelably connected to the piston; and    an anti-frictional thrust bearing having first and second race elements in parallel relation with a bearing element positioned therebetween directly engaging the slippers.    
   
   
       2 . The axial piston pump of  claim 1  wherein the piston has a first end forming a ball portion that swivelably engages the pseudo slippers.  
   
   
       3 . The axial piston pump of  claim 1  wherein the piston has a first end forming a female groove that swivelably engages a male portion of the pseudo slipper.  
   
   
       4 . The axial piston pump of  claim 1  wherein the anti-frictional thrust bearing is a ball bearing.  
   
   
       5 . The axial piston pump of  claim 1  wherein the anti-frictional thrust bearing is a roller bearing.  
   
   
       6 . The axial piston pump of  claim 1  wherein the anti-frictional thrust bearing is a tapered roller bearing.  
   
   
       7 . An axial piston pump having a cylinder block comprising: 
 an elongated piston body having a bore disposed within the cylinder block;    a spring securely connected to the piston;    a slipper element swivelably connected to the piston body such that the spring creates a hold down force on the slipper element; and    an anti-frictional thrust bearing directly engaging the slipper element.    
   
   
       8 . The axial piston pump of  claim 7  wherein the piston body has a first end forming a ball portion that swivelably engages the slipper element.  
   
   
       9 . The axial piston pump of  claim 7  wherein the piston body has a first end forming a female groove that swivelably engages a male portion of the slipper element.  
   
   
       10 . The axial piston pump of  claim 7  wherein the anti-frictional thrust bearing is a ball bearing.  
   
   
       11 . The axial piston pump of  claim 7  wherein the anti-frictional thrust bearing is a roller bearing.  
   
   
       12 . The axial piston pump of  claim 7  wherein the anti-frictional thrust bearing is a tapered roller bearing.