Integrated electro-hydraulic unit having an internal position sensor

Abstract

An integrated electro-hydraulic unit includes a hydraulic machine, an electric machine, a position sensor, and a housing enclosing the hydraulic machine, the electric machine, and the position sensor. The hydraulic machine has a rotary working group configured to pump a working fluid. The rotary working group has a shaft. The electric machine includes an electric machine stator and an electric machine rotor which is driven by an electric field produced by the stator and which drives the shaft of the rotary working group. The position sensor is at least partially positioned on the shaft and is configured to sense a positional characteristic of the shaft.

What is claimed is: 
     
         1 . An integrated electro-hydraulic unit comprising:
 a hydraulic machine including a rotary working group configured to pump a working fluid, the rotary working group having a shaft;   an electric machine including an electric machine stator and an electric machine rotor which is driven by an electric field produced by the stator and which drives the shaft of the rotary working group;   a position sensor at least partially positioned on the shaft and configured to sense a positional characteristic of the shaft; and   a shared housing enclosing the hydraulic machine, the electric machine, and the position sensor.   
     
     
         2 . The integrated electro-hydraulic unit of  claim 1 , wherein the position sensor is a rotary encoder. 
     
     
         3 . The integrated electro-hydraulic unit of  claim 1 , wherein the position sensor is a resolver. 
     
     
         4 . The integrated electro-hydraulic unit of  claim 3 , wherein the position sensor has a resolver rotor mounted on the shaft and a resolver stator mounted on the shared housing. 
     
     
         5 . The integrated electro-hydraulic unit of  claim 1 , further comprising an electric connector configured to carry power to the electric machine and having control pins, wherein the position sensor is electrically coupled to the control pins of the electric connector. 
     
     
         6 . The integrated electrohydraulic unit of  claim 1 , wherein the hydraulic machine, the electric machine and the position sensor are sealed in the shared housing. 
     
     
         7 . The integrated electro-hydraulic unit of  claim 1 , wherein the positional characteristic is at least one of an angular speed, an angular position and a change of angular position. 
     
     
         8 . An integrated electro-hydraulic unit comprising:
 a hydraulic machine including a rotary working group configured to pump a working fluid, the rotary working group having a shaft which defines a rotational axis and a bearing which supports the shaft;   an electric machine encircling the hydraulic machine, the electric machine including an electric machine stator and an electric machine rotor which is driven by an electric field produced by the stator and which drives the shaft of the rotary working group;   a position sensor at least partially positioned on the shaft and configured to sense a positional characteristic of the shaft; and   a housing at least partially surrounding the hydraulic machine and the electric machine,   wherein, along the rotational axis, the position sensor is positioned between the bearing and an internal surface of the housing.   
     
     
         9 . The integrated electro-hydraulic unit of  claim 8 , wherein the position sensor is a resolver which includes a resolver stator and a resolver rotor, wherein the resolver stator is mounted to the housing, and the resolver rotor is mounted to the shaft. 
     
     
         10 . The integrated electro-hydraulic unit of  claim 9 , wherein the housing includes an axial plate and a projection extending from the axial plate, and wherein the bearing and the resolver stator are mounted to the projection. 
     
     
         11 . The integrated electro-hydraulic unit of  claim 10 , wherein the projection defines a recess, and wherein the bearing and the position sensor are positioned in the recess of the projection. 
     
     
         12 . The integrated electro-hydraulic unit of  claim 8 , wherein the bearing is a first bearing, wherein the rotary working group includes a second bearing supporting the shaft, and wherein, along the rotational axis, the first bearing is positioned between the second bearing and the position sensor. 
     
     
         13 . The integrated electro-hydraulic unit of  claim 12 , wherein the housing includes a front axial plate, a projection extending from the front axial plate, an end axial plate, and a protrusion extending from the end axial plate, and wherein the first bearing is mounted to the projection and the second bearing is mounted to the protrusion. 
     
     
         14 . An integrated electro-hydraulic unit comprising:
 a hydraulic machine including a rotary working group configured to pump a working fluid, the rotary working group having a shaft defining a rotational axis,   an electric machine encircling the hydraulic machine, the electric machine including an electric machine stator and an electric machine rotor which is driven by an electric field produced by the stator and which drives the shaft of the rotary working group;   a position sensor at least partially positioned on the shaft and configured to sense a positional characteristic of the shaft;   a housing at least partially surrounding the hydraulic machine and the electric machine, the housing defining a first axial end and a second axial end opposite the first axial end, the second axial end being spaced from the first axial end along the rotational axis,   wherein the position sensor is positioned between the first axial end and the second axial end of the housing.   
     
     
         15 . The integrated electro-hydraulic unit of  claim 14 , wherein the position sensor has a fixed portion mounted to the housing and a movable portion mounted to the shaft, and wherein the fixed portion is fixed relative to the housing and the movable portion rotates relative to the housing. 
     
     
         16 . The integrated electro-hydraulic unit of  claim 14 , wherein the shaft is positioned between the first axial end and the second axial end of the housing. 
     
     
         17 . The integrated electro-hydraulic unit of  claim 16 , wherein the rotary working group includes a bearing supporting the shaft, and wherein the position sensor is positioned between the first axial end and the bearing. 
     
     
         18 . The integrated electro-hydraulic unit of  claim 14 , wherein the hydraulic machine, the electric machine and the position sensor are sealed within the housing. 
     
     
         19 . The integrated electro-hydraulic unit of  claim 14 , further comprising an electric connector having main power cables configured to carry power to the electric machine, wherein the housing is sealed and the electric connector is sealed to the housing such that the hydraulic machine, the electric machine and the position sensor are sealed within the housing. 
     
     
         20 . The integrated electro-hydraulic unit of  claim 14 , wherein the shaft has a first end and a second end opposite the first end, wherein the housing has a first axial wall defining the first axial end of the housing and a second axial wall defining the second axial end of the housing, and wherein the first end of the shaft is positioned within a first recess of the first axial wall and the second end of the shaft is positioned within a second recess of the second axial wall.