Ducted cooling arrangement for hydrostatic pumps

Abstract

A hydrostatic pump assembly having an improved cooling arrangement. The pump assembly includes a hydrostatic pump having a housing which rotatably supports a drive shaft, and a fan is coupled to an external end of the drive shaft for rotation therewith. The housing includes a plurality of integrally formed, elongated fins which define a plurality of passages extending along the housing in a direction substantially parallel to the drive shaft. The housing also includes a flange at an end thereof proximate the cooling fan, the flange including at least one duct therethrough. The flange is secured to a wall of an implement with the housing disposed on one side of the wall and the cooling fan the opposite side of the wall. In operation, cooling air is drawn by the fan through the passages along the housing, and passes through the flange ducts at a relatively high velocity before being discharged radially from the fan on the side of the wall opposite the housing, thereby providing an enhanced cooling effect for efficient cooling of the pump.

1 . A hydrostatic pump assembly, comprising: 
 a housing;    a drive shaft rotatably supported by said housing and including an end extending externally of said housing;    a fan coupled to said drive shaft end for rotation therewith; and    a plurality of fins formed integrally with said housing and extending along a substantial extent of said housing in a direction substantially parallel to said drive shaft, said fins defining a plurality of passages therebetween, whereby upon rotation of said fan, cooling air is drawn through said passages along said housing to cool said housing.    
   
   
       2 . The pump assembly of  claim 1 , wherein said housing has a long dimension defined in a direction substantially parallel with said drive shaft, and said fins and said passages are elongate in profile and extend along said long dimension.  
   
   
       3 . The pump assembly of  claim 1 , wherein said housing includes a flange at and end thereof proximate said fan, said flange including at least one duct aligned with said passages, whereby cooling air is drawn through said at least one duct after passing through said passages.  
   
   
       4 . The pump assembly of  claim 3 , wherein said flange is disposed closely adjacent said fan, whereby cooling air is drawn into said fan substantially immediately after passing through said at least one duct.  
   
   
       5 . The pump assembly of  claim 3 , wherein said flange includes a plurality of said ducts, said ducts arranged circumferentially around said drive shaft and aligned with said passages.  
   
   
       6 . The pump assembly of  claim 1 , wherein said fan is shaped to discharge cooling air substantially radially evenly around said fan.  
   
   
       7 . The pump assembly of  claim 1 , in combination with a wall having a first side to which said housing is secured, said wall including an opening through which said drive shaft extends with said fan disposed on a second side of said wall opposite said first side, whereby cooling air is drawn from around said housing, through said wall opening, and is discharged on said second wall side.  
   
   
       8 . A hydrostatic pump assembly, comprising: 
 a housing including a flange at one end thereof;    a drive shaft rotatably supported by said housing, said drive shaft including an end extending externally of said housing;    a fan coupled to said drive shaft end for rotation therewith, said fan disposed on a side of said flange opposite said housing; and    at least one duct formed through said flange, whereby upon rotation of said fan, cooling air is drawn from around said housing, passes through said at least one duct, and is discharged from said fan.    
   
   
       9 . The pump assembly of  claim 8 , wherein said flange includes a plurality of said ducts spaced circumferentially around said drive shaft.  
   
   
       10 . The pump assembly of  claim 8 , wherein said flange is disposed closely adjacent said fan, whereby cooling air is drawn into said fan substantially immediately after passing through said at least one duct.  
   
   
       11 . The pump assembly of  claim 8 , wherein said fan is shaped to discharge cooling air substantially radially evenly around said fan.  
   
   
       12 . The pump assembly of  claim 8 , in combination with a wall having a first side to which said flange of said housing is secured, said wall including an opening aligned with said at least one duct and through which said drive shaft extends with said cooling fan disposed on a second side of said housing opposite said first side, whereby upon rotation of said fan, cooling air is drawn from around said housing, passes through said at least one duct, and is discharged from said fan on said second wall side.  
   
   
       13 . The pump assembly of  claim 8 , wherein said housing includes a plurality of elongated fins formed integrally with said housing and extending along said housing in a direction substantially parallel to said drive shaft, said fins defining a plurality of passages in said housing, whereby upon rotation of said fan, air is drawn through said passages along said housing to cool said housing.  
   
   
       14 . A hydrostatic pump assembly, comprising: 
 a housing;    a flange at one end of said housing, said flange including at least one duct therethrough;    a drive shaft rotatably supported by said housing, said drive shaft including an end extending externally of said housing;    a wall to which said flange is secured, said housing disposed on a first side of said wall and said drive shaft end extending through an opening in said wall to an opposite, second side of said wall, said opening aligned with said at least one duct; and    a fan coupled to said drive shaft end for rotation therewith, said fan disposed on said second side of said wall, whereby upon rotation of said fan, cooling air is drawn from said first side of said wall around said housing to cool said housing, passes through said at least one duct and said wall opening, and is discharged from said fan on said second side of said wall.    
   
   
       15 . The pump assembly of  claim 14 , wherein said housing includes a plurality of elongated fins formed integrally with said housing and extending along said housing in a direction substantially parallel to said drive shaft, said fins defining a plurality of passages in said housing, whereby upon rotation of said fan, air is drawn through said passages along said housing to cool said housing.  
   
   
       16 . The pump assembly of  claim 14 , wherein said flange is disposed closely adjacent said cooling fan, whereby cooling air is drawn into said cooling fan substantially immediately after passing through said at least one duct.  
   
   
       17 . The pump assembly of  claim 14 , wherein said fan is shaped to discharge cooling air substantially radially evenly about said fan.