Radial piston pumps and motors

Abstract

A radial piston pump 101 comprising a rotor 103 is disclosed. The rotor 103 includes a drive shaft 105 arranged to transmit rotary motion to or from the pump 101 and a piston housing 102 including at least one piston chamber 104 , the at least one piston chamber 104 being arranged to receive a piston 108 . The drive shaft 105 and the piston housing 102 are integrally formed.

1 . A radial piston pump comprising a rotor, the rotor including a drive shaft arranged to transmit rotary motion to or from the pump and a piston housing including at least one piston chamber, the at least one piston chamber being arranged to receive a piston and wherein the drive shaft and the piston housing are integrally formed. 
     
     
         2 . A radial piston pump according to  claim 1 , wherein the pump further comprises a main housing, the rotor being mounted for rotation relative to the main housing, the main housing comprising a first cam surface arranged to control the radial movement of a piston located in the at least one piston chamber when the pump is in use and wherein the main housing and the first cam surface are integrally formed. 
     
     
         3 . A radial piston pump according to  claim 2 , wherein the rotor further comprises a sequencing assembly arranged to control the flow of fluid into and out of the at least one piston chamber as the rotor rotates relative to the main housing and wherein at least part of the sequencing assembly is integrally formed with the rotor and/or the main housing. 
     
     
         4 . A radial piston pump according to  claim 3 , wherein the sequencing assembly comprises a first set of ports integrally formed with the rotor. 
     
     
         5 . A radial piston pump according to  claim 3 , wherein the sequencing assembly comprises a second set of ports integrally formed with the main housing. 
     
     
         6 . A radial piston pump according to  claim 5 , wherein the main housing further comprises at least one integrally formed pump inlet or pump outlet and at least one integrally formed flow gallery connecting the at least one pump inlet or pump outlet with a port of the second set. 
     
     
         7 . A radial piston pump according to  claim 2 , wherein the main housing further comprises a second cam surface spaced apart from the first cam surface. 
     
     
         8 . A radial piston pump according to  claim 1 , wherein the rotor includes a first series of piston chambers spaced apart around the circumference of the piston housing at a first location and a second series of piston chambers spaced apart around the circumference of the piston housing at a second location, spaced apart from the first location along the longitudinal axis of the rotor. 
     
     
         9 . (canceled) 
     
     
         10 . A radial piston pump according to  claim 1 , wherein the pump is an inside impinged pump. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . A method of manufacturing a radial piston pump, the pump comprising a drive shaft arranged to transmit rotary motion to or from the pump and a piston housing including at least one piston chamber, the piston chamber being arranged to receive a piston, the method comprising the step of forming a rotor including the drive shaft and the piston housing as a single piece using an additive manufacturing process. 
     
     
         14 . A method according to  claim 13 , wherein the pump further comprises a main housing, the main housing comprising a first cam surface arranged to control the radial movement of a piston located in that at least one piston chamber, and wherein the method further comprises the step of forming the main housing and the first cam surface as a single piece using an additive manufacturing process. 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . A radial piston pump comprising at least one piston mounted for reciprocal movement in a piston housing and a cam including a cam surface arranged to control the motion of the at least one piston when the piston housing rotates relative to the cam about a first axis, wherein the cam is mounted for axial movement relative to the piston housing along the first axis and the profile of the cam surface varies across the width of the cam such that moving the cam relative to the piston housing along the first axis changes the motion of the piston. 
     
     
         18 . A radial piston pump according to  claim 17 , wherein the profile of the cam surface varies across the width of the cam such that moving the cam relative to the piston assembly along the first axis changes the amplitude of the piston motion. 
     
     
         19 . A radial piston pump according to  claim 17 , wherein the profile of the cam surface varies across the width of the cam such that moving the cam relative to the piston assembly along the first axis changes the frequency of the piston motion. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . A radial piston pump according to  claim 17 , wherein the piston is mounted for reciprocal movement in a piston chamber formed in the piston housing and the pump further comprises a sequencing element arranged to permit the flow of fluid into and out of the piston chamber as the piston housing rotates relative to the sequencing assembly about the first axis, and wherein the cam is mounted for rotation about the first axis relative to the sequencing element such that the phase difference between the movement of the piston and the flow of fluid to and from the piston chamber can be varied. 
     
     
         23 . A radial piston pump according to  claim 17 , wherein a hydraulic actuator is arranged to move the cam relative to the piston assembly along the first axis. 
     
     
         24 . A radial piston pump according to  claim 17 , wherein the cam surface is located radially outside the piston housing. 
     
     
         25 . A radial piston pump according to  claim 17 , wherein the pump is an internally impinged radial piston pump. 
     
     
         26 . A radial piston pump according to  claim 17 , wherein the pump comprises a plurality of piston assemblies, each piston assembly including
 at least one of the plurality of pistons,   a roller arranged to follow the cam surface when the piston housing rotates relative to the cam surface, and   a thrust bearing, the axis of the thrust bearing being parallel to the first axis.   
     
     
         27 . A radial piston pump according to  claim 17 , wherein the profile of the cam surface is arranged to provide 2 or more piston cycles per revolution. 
     
     
         28 . A method of varying the flow of fluid through a radial piston pump, the piston pump comprising a piston housing including a plurality of pistons mounted therein and a cam surface, each piston being connected to a cam follower arranged to follow the cam surface when the piston housing rotates relative to the cam surface about a first axis, and wherein the profile of the cam surface varies with distance along the first axis, the method comprising the steps of:
 rotating the piston housing relative to the cam surface at a first location such that a first piston motion is produced,   rotating the piston housing relative to the cam surface at a second location, spaced apart from the first location along the first axis, such that a second, different, piston motion is produced.   
     
     
         29 . (canceled) 
     
     
         30 . A method according to  claim 28 , wherein the piston pump further comprises a sequencing element and the method further comprises the step of rotating the cam about the first axis from a first angular position relative to the sequencing element to a second angular position relative to the sequencing element such that the flow of fluid through the pump is reversed. 
     
     
         31 . (canceled) 
     
     
         32 . (canceled) 
     
     
         33 . A radial piston pump comprising a primary cam surface, at least one secondary cam surface and at least one piston assembly comprising a first piston, the first piston being mounted for reciprocal movement in a piston housing, said piston housing being arranged to rotate relative to the primary cam surface, the piston assembly further comprising
 a primary roller connected to the first piston and arranged to follow the primary cam surface when the piston housing rotates relative to the primary cam surface, and   a secondary roller connected to the first piston and arranged to follow a secondary cam surface as the primary roller follows the primary cam surface.   
     
     
         34 . A radial piston pump according to  claim 33 , wherein the piston housing is arranged to rotate relative to the at least one secondary cam surface. 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . (canceled) 
     
     
         38 . A radial piston pump according to  claim 33 , wherein the at least one secondary cam surface defines a recess arranged to receive the secondary roller while the primary roller follows the primary cam surface. 
     
     
         39 . (canceled) 
     
     
         40 . (canceled) 
     
     
         41 . A radial piston pump according to  claim 33 , wherein the piston assembly comprises a second piston, the first and second pistons being arranged on either side of the primary roller. 
     
     
         42 . (canceled) 
     
     
         43 . (canceled) 
     
     
         44 . (canceled) 
     
     
         45 . (canceled) 
     
     
         46 . A radial piston pump according to  claim 33 , wherein the primary or secondary roller comprises a member connected to the piston assembly by a roller bearing and the pump is arranged such that, in use, the surface of the roller adjacent to the cam surface is the outer surface of the member. 
     
     
         47 . A radial piston pump according to  claim 33 , wherein the piston assembly comprises a thrust bearing. 
     
     
         48 . (canceled) 
     
     
         49 . (canceled) 
     
     
         50 . (canceled) 
     
     
         51 . (canceled) 
     
     
         52 . (canceled)