hydraulic motor device for assisting the mechanical transmission of a vehicle

Abstract

A hydraulic motor device including a hydraulic motor having a cylinder block and a cam that are mounted to move in rotation relative to each other. The motor has a fluid distributor for the cylinders, a portion of which distributor is constrained in rotation with the cam, and a stationary distribution coupling connecting the distributor to a fluid feed and to a fluid discharge. The motor has a through passage disposed along the axis of rotation for the purpose of receiving a transmission shaft segment. The motor can be declutched by radially uncoupling the pistons from the cam, the cylinder block remaining stationary relative to the reference frame of the vehicle, and the cam being constrained in rotation with a transmission shaft segment that is disposed in the through passage. The device may be used in addition to or as a replacement for a mechanical transmission.

1 - 16 . (canceled) 
     
     
         17 . A hydraulic motor device, in particular for assisting the mechanical transmission of a vehicle, which hydraulic motor device includes a hydraulic motor that comprises a cylinder block having cylinders slidably receiving radial pistons, and a reaction cam for the pistons, the cylinder block and the cam being mounted to move in rotation relative to each other about an axis of rotation, the motor further comprising a fluid distributor for the cylinders, a portion of which distributor is constrained in rotation with the cam, and a distribution coupling mounted to be stationary relative to a reference frame of the vehicle and for connecting the distributor to a fluid feed and to a fluid discharge, the motor having a through passage disposed along the axis of rotation for the purpose of receiving a transmission shaft segment, wherein the motor can take up a declutched configuration in which the pistons are radially uncoupled from the cam, the cylinder block is stationary relative to the reference frame of the vehicle, while the cam is rotary, and the cam is constrained in rotation with a transmission shaft segment that is disposed in said through passage. 
     
     
         18 . A device according to  claim 17 , further including a drive part secured to the cam and that is suitable for co-operating with said transmission shaft segment to drive said shaft segment in rotation. 
     
     
         19 . A device according to  claim 18 , wherein the drive part and the transmission shaft segment are formed integrally as a single part. 
     
     
         20 . A device according to  claim 17 , wherein, on its periphery, the hydraulic motor has a connection portion adapted to transmit torque. 
     
     
         21 . A device according to  claim 17 , wherein the distribution coupling has a sleeve portion whose inside periphery forms a portion of the through passage. 
     
     
         22 . A device according to  claim 21 , wherein the distributor is disposed around said sleeve portion. 
     
     
         23 . A device according to  claim 21 , wherein the sleeve portion extends in an internal passage in the cylinder block. 
     
     
         24 . A device according to  claim 21 , wherein the sleeve portion co-operates with at least one rotary support bearing for supporting the shaft segment in rotation relative to the motor. 
     
     
         25 . A device according to  claim 17 , wherein the distributor is disposed on the other side of the cylinder block from the fluid feed and fluid discharge. 
     
     
         26 . A device according to  claim 25 , wherein the distributor is connected to the fluid feed and to the fluid discharge via ducts passing through the cylinder block between the cylinders. 
     
     
         27 . A device according to  claim 17 , wherein the distributor is disposed on the same side of the cylinder block as the fluid feed and fluid discharge. 
     
     
         28 . A device according to  claim 17 , wherein the cylinders extend radially relative to the axis of rotation, and the cam surface of the reaction cam is disposed around the cylinder block and faces towards the axis of rotation. 
     
     
         29 . A device according to  claim 17 , wherein the distributor for the cylinders is constrained in rotation with the cam. 
     
     
         30 . A vehicle drive system, comprising a mechanical transmission operated by at least one main engine or motor, and a device according to  claim 17 , the transmission shaft segment being a portion of the mechanical transmission. 
     
     
         31 . A vehicle drive system according to  claim 30 , in which system the transmission shaft segment is a portion of a main transmission shaft connected to the main engine or motor. 
     
     
         32 . A vehicle drive system according to  claim 30 , in which the transmission shaft segment is a portion of a secondary transmission shaft that is connected to a main transmission shaft of the mechanical transmission.