Hydraulic piston pump and method for affecting the sound character of the piston pump

Abstract

A hydraulic piston pump comprising a plurality of pistons, wherein each piston is arranged in a cylinder barrel, wherein at least one piston is arranged to deliver a specific pressure or output flow that differs from the pressure or output flow delivered by the other pistons.

1 . A hydraulic piston pump comprising a plurality of pistons, wherein each piston is arranged in a cylinder barrel, wherein at least one piston is arranged to deliver a specific pressure or output flow that differs from the pressure or output flow delivered by the other pistons. 
     
     
         2 . The hydraulic piston pump according to  claim 1 , wherein the length of at least one piston differs from the length of the other pistons. 
     
     
         3 . The hydraulic piston pump according to  claim 1 , wherein the length of at least one piston shaft differs from the length of the other piston shafts. 
     
     
         4 . The hydraulic piston pump according to  claim 1 , wherein the upper surface of at least one piston differs from the upper surface of the other pistons. 
     
     
         5 . The hydraulic piston pump according to  claim 1 , wherein the stiffness of at least one piston shaft differs from the stiffness of the other piston shafts. 
     
     
         6 . The hydraulic piston pump according to  claim 1 , wherein the diameter of at least one piston differs from the diameter of the other pistons. 
     
     
         7 . The hydraulic piston pump according to  claim 1 , wherein the hydraulic piston pump is a bent axis piston pump. 
     
     
         8 . The hydraulic piston pump according to  claim 1 , wherein the hydraulic piston pump is a swashplate piston pump. 
     
     
         9 . A vehicle comprising a hydraulic piston pump according  claim 1 . 
     
     
         10 . A method for affecting the emitted sound character from a hydraulic piston pump comprising a plurality of pistons arranged in a cylinder barrel, wherein the cylinder barrel is rotated by an input shaft such that the pistons move back and forth in the cylinder barrel, thereby creating an output pressure and output flow, the method comprising:
 providing a specific output pressure or output flow from at least one piston, and   providing a specific output pressure or output flow from at least one piston that differs from the output pressure or output flow from the other pistons.   
     
     
         11 . The method according to  claim 10 , wherein the different output pressure from at least one piston is obtained by using a piston with a length that differs from the other piston lengths. 
     
     
         12 . The method according to  claim 10 , wherein the different output pressure from at least one piston is obtained by using a piston shaft with a length that differs from the other piston shaft lengths. 
     
     
         13 . The method according to  claim 10 , wherein the different output pressure from at least one piston is obtained by using a piston with an upper shape that differs from the upper shape of the other pistons. 
     
     
         14 . The method according to  claim 10 , wherein the different output pressure from at least one piston is obtained by using a piston shaft with a stiffness that differs from the stiffness of the other piston shafts. 
     
     
         15 . The method according to  claim 10 , wherein the different output flow from at least one piston is obtained by using a piston having a diameter that differs from the diameter of the other pistons.