Motor or pump assemblies

Abstract

A hydraulic device includes a rotatable drum, at least one piston, a transition arm, and at least one compensating piston. The rotatable drum defines a cylinder that houses the piston. The transition arm is coupled to the piston to translate between linear motion of the piston and rotation of the rotatable drum. The compensating piston is in fluidic communication with the cylinder and is configured to counteract a force caused by an inlet or an output pressure during operation.

1 . A hydraulic device comprising: 
 a rotatable drum defining at least one cylinder;    at least one piston housed in the cylinder;    a transition arm coupled to the at least one piston and configured to translate between linear motion of the piston and rotation of the rotatable drum; and    at least one compensating piston in fluidic communication with the cylinder and configured to counteract a force caused by at least one of an inlet pressure and an output pressure during operation.    
   
   
       2 . The hydraulic device of  claim 1  further comprising: 
 a shaft connected to the rotatable drum such that the rotatable drum does not move axially along the shaft;    a member mounted on the shaft;    wherein the at least one compensating piston is configured to counteract the force caused by at least one of the inlet pressure and the output pressure during operation by applying a force to the member.    
   
   
       3 . The hydraulic device of  claim 2  further comprising: 
 a flanged nut mounted to the shaft;    a spring mounted to the shaft between the member and the flanged nut such that the spring applies a force to the flanged nut in the same direction as the force applied to the member by the compensating piston.    
   
   
       4 . The hydraulic device of  claim 3  wherein the member is mounted on the shaft such that the member moves axially along the shaft and the at least one compensating piston is configured to counteract the force caused by at least one of the inlet pressure and the output pressure during operation by applying a force to the member such that the member moves axially along the shaft to compress the spring, resulting in an increase in the force applied to the flanged nut by the spring.  
   
   
       5 . The hydraulic device of  claim 2  wherein the member comprises a plate.  
   
   
       6 . The hydraulic device of  claim 1  comprising a hydraulic motor.  
   
   
       7 . The hydraulic device of  claim 6  further comprising: 
 a bulkhead defining: 
 an inlet manifold connected to an inlet;  
 a cylinder housing the compensating piston; and  
 a port between the inlet manifold and the cylinder housing the compensating piston to provide the fluidic communication between the compensating piston and the cylinder defined by the rotatable drum.  
   
   
   
       8 . The hydraulic device of  claim 1  comprising a hydraulic pump.  
   
   
       9 . The hydraulic device of  claim 8  further comprising: 
 a bulkhead defining: 
 an outlet manifold connected to an outlet;  
 a cylinder housing the compensating piston; and  
 a port between the cylinder housing the compensating piston and the outlet manifold to provide the fluidic communication between the compensating piston and the cylinder defined by the rotatable drum.  
   
   
   
       10 . The hydraulic device of  claim 1  further comprising: 
 a shaft connected to the rotatable drum such that the rotatable drum moves axially along the shaft;    a member mounted to the shaft such that the member does not move axially along the shaft; and    wherein the at least one compensating piston is configured to counteract the force caused by at least one of the inlet pressure and the output pressure during operation by applying a force to the member.    
   
   
       11 . The hydraulic device of  claim 10  further comprising a U-joint coupled to the member and the transition arm.  
   
   
       12 . The hydraulic device of  claim 10  wherein the at least one compensating piston is configured to counteract the force caused by at least one of the inlet pressure and the output pressure during operation by applying a force to the member such that a force is applied to the rotatable drum in a direction opposite to the force caused by the inlet or output pressure.  
   
   
       13 . The hydraulic device of  claim 10  further comprising: 
 a spring mounted between the member and the rotatable drum such that the spring applies a force to the rotatable drum in the opposite direction of the force caused by the inlet or output pressure during operation.    
   
   
       14 . The hydraulic device of  claim 10  wherein the member comprises a support.  
   
   
       15 . The hydraulic device of  claim 1  further comprising: 
 a bulkhead defining: 
 a cylinder housing the compensating piston; and  
 a port between the cylinder housing the compensating piston and the cylinder defined by the rotatable drum to provide the fluidic communication between the cylinder defined by the rotatable drum and the compensating piston.  
   
   
   
       16 . The hydraulic device of  claim 1  further comprising 
 a bulkhead;    a face valve between the bulkhead and the rotatable drum; and    wherein the compensating piston is configured to counteract the force caused by at least one of the inlet pressure and the output pressure during operation to maintain a seal between the face valve and the bulkhead or the face valve and the rotatable drum.    
   
   
       17 . The hydraulic device of  claim 1  further comprising: 
 a spring coupled to the at least one compensating piston such that the spring applies a force to the rotatable drum in the opposite direction of the force caused by the inlet or output pressure during operation.    
   
   
       18 . The hydraulic device of  claim 1  wherein the at least one compensating piston is configured to counteract the force caused by at least one of the inlet pressure and the output pressure during operation by creating a force that acts on the rotatable drum in a direction opposite to the force caused by the inlet or output pressure.  
   
   
       19 . The hydraulic device of  claim 1  further comprising: 
 a non-rotating member coupled to the transition arm, wherein a radial position of the non-rotating member relative to an axis of rotation of the rotatable drum is adjustable to change an angle between the transition arm and the axis of rotation of the rotatable drum.    
   
   
       20 . The hydraulic device of  claim 19  wherein the transition arm is coupled to the piston and the non-rotating member such that a change in the angle between the transition arm and the axis of rotation of the rotatable drum changes a stroke of the piston.  
   
   
       21 . The hydraulic device of  claim 19  wherein the non-rotating member includes teeth that mesh with a gear such that rotation of the gear adjusts the radial position of the non-rotating member relative to the axis of rotation of the rotatable drum.  
   
   
       22 . The hydraulic device of  claim 1  further comprising: 
 a piston joint assembly coupling the transition arm to the piston, the piston joint assembly configured to reduce centrifugal forces acting on the piston as a result of rotation of the rotatable drum and piston.    
   
   
       23 . The hydraulic device of  claim 22  wherein the piston joint assembly comprises: 
 a casing that defines a hole through which a portion of the piston extends, the hole having a diameter larger than the portion of the piston extending through the hole.    
   
   
       24 . The hydraulic device of  claim 23  wherein the portion extending through the hole of the casing terminates in a head piece, the head piece having a diameter larger than the hole defined by the casing, the casing being dimension to provide a spacing between an inner surface of the casing and the head piece.  
   
   
       25 . A hydraulic device comprising 
 a rotatable drum defining at least one cylinder;    at least one piston housed in the cylinder;    a transition arm coupled to the at least one piston and configured to translate between linear motion of the piston and rotation of the rotatable drum; and    means for counteract a force caused by at least one of an inlet pressure and an output pressure during operation.    
   
   
       26 . A method for counteracting a force in a hydraulic device caused by at least one of an inlet pressure and an outlet pressure during operation, the method comprising: 
 adjusting a counteracting force as at least one of the inlet pressure or the outlet pressure changes during operation.    
   
   
       27 . A method for counteracting a force in a hydraulic device caused by at least one of an inlet pressure and an outlet pressure, the method comprising: 
 rotating a drum that defines a cylinder;    reciprocating a piston in the cylinder;    communicating a pressure in the cylinder to a compensating piston such that the compensating piston creates a force that counteracts the force caused by at least one of an inlet pressure and an outlet pressure during operation.