Axle driving apparatus

Abstract

An axle assembly has a housing. A hydrostatic transmission separate from the housing is mounted therein. Horizontal axle shafts are rotatably supported in the housing. The hydrostatic transmission includes a center section separate from the housing with fluid conduits connected to hydrostatic rotatable cylinder blocks. A drive shaft extends from one of the blocks and is operatively connected to the axle shafts. Check valves are associated with the conduits to affect fluid flow and are positioned to move in a vertical path at right angles to the axle shafts.

I claim:  
     
         1 . An axle assembly, comprising 
 a housing for an internally disposed hydrostatic transmission,    a hydrostatic transmission separate from the housing and mounted within the housing,    axle shafts rotatably supported in the housing and having horizontal axes,    the hydrostatic transmission including a center section separate from the housing and having fluid conducting conduits interconnecting hydrostatic rotatable cylinder blocks,    a drive shaft extending from one of the cylinder blocks and being operatively connected to the axle shafts,    check valves associated with the fluid conducting conduits and including check valve balls to affect fluid flow through the conduits and being positioned to move in a vertical path in a direction at right angles to the axes of the axle shafts.    
     
     
         2 . An axle assembly, comprising 
 a housing for an internally disposed hydrostatic transmission,    a hydrostatic transmission separate from the housing and mounted within the housing,    axle shafts rotatably supported in the housing and having horizontal axes,    the hydrostatic transmission including a center section separate from the housing and having fluid conducting conduits interconnecting hydrostatic rotatable cylinder blocks,    the center section having a horizontal base portion, and a vertical portion extending upwardly therefrom to create an L-shape,    a drive shaft extending from one of the cylinder blocks and being operatively connected to the axle shafts,    check valves associated with the fluid conducting conduits and including check valve balls to affect fluid flow through the conduits,    the check valves being located in the horizontal base portion of the center section.    
     
     
         3 . The axle assembly of  claim 1  wherein the check valve balls are positioned to move in a vertical path in a direction at right angles to the axes of the axle shafts.  
     
     
         4 . The axle assembly of  claim 1  wherein movement of the balls in a vertical direction will short circuit the flow of fluid between the cylinder blocks to create a bypass mode whereupon the hydrostatic transmission is inoperative to drive the axle shafts and the axle shafts are free to rotate without hydraulic resistance from the rotatable cylinder blocks.  
     
     
         5 . The axle assembly of  claim 4  wherein rotatable means is operative with the check valves to selectively raise the balls in a vertical direction.  
     
     
         6 . The axle assembly of  claim 4  wherein the rotatable means includes a bypass actuation rod which is vertically positioned in the housing for vertical movement in a direction at right angles to the axes of the axle shafts.  
     
     
         7 . The axle assembly of  claim 1  further comprising a differential mounted in said housing and being operatively connected to said drive shaft and said axle shafts.  
     
     
         8 . The axle assembly of  claim 7  further comprising a gear train mounted in said housing, said gear train driven by said drive shaft and connected to said differential.  
     
     
         9 . An axle assembly, comprising 
 a housing forming an oil sump;    a hydrostatic transmission mounted within said housing and comprising a hydraulic circuit interconnecting first and second hydrostatic rotatable cylinder blocks;    said hydraulic circuit having a closed state wherein hydraulic fluid is transferred between said first and second rotatable cylinder blocks and an open state where the circuit is open to the sump;    an input shaft drivingly connected to said first rotatable cylinder block;    an output shaft drivingly connected to said second rotatable cylinder block, wherein said output shaft is mounted perpendicular to said input shaft;    a rotatable bypass arm mounted in said housing parallel to said input shaft and rotatable to move said hydraulic circuit from its closed position to its open position.    
     
     
         10 . The axle assembly of  claim 9  further comprising a cam mechanism associated with said rotatable bypass arm.  
     
     
         11 . The axle assembly of  claim 9  further comprising a plurality of check valves mounted in said center section, wherein said check valves are closed when the circuit is in its closed position and the check valves are open when the circuit is in its open position.  
     
     
         12 . The axle assembly of  claim 9  further comprising a plurality of check valves mounted in said center section and connected between said hydraulic circuit and said sump, wherein the check valves are operatively connected to the rotatable bypass arm so that rotation of the arm opens the check valves to place the hydraulic circuit in its open position.  
     
     
         13 . An axle assembly comprising: 
 a housing forming a fluid sump;    a hydrostatic transmission mounted in said housing and comprising a center section, a hydrostatic pump mounted on the center section and a hydrostatic motor mounted on the center section;    an input shaft operatively connected to the hydraulic pump and having a generally vertical axis;    an output shaft operatively connected to the hydraulic motor and having a generally horizontal axis;    a pair of axles mounted in the housing parallel to said shaft, said axles being drivingly connected to the output shaft;    hydraulic porting formed in the center section to hydraulically connect the pump and motor, said porting comprising at least two vertically disposed check passages formed generally parallel to said input shaft to permit oil to flow between the hydraulic porting and the fluid sump.    
     
     
         14 . The axle assembly of  claim 13 , wherein said center section comprises a horizontal base portion on which said hydrostatic pump is mounted and a vertical portion extending therefrom on which said hydrostatic motor is mounted, and said check passages are formed in said horizontal base portion.  
     
     
         15 . The axle assembly of  claim 13 , further comprising check valves mounted in both said check passages.