Heat pipe cooler for differential assembly

Abstract

The present invention is directed to an apparatus to regulate and control the temperature of a differential axle assembly. A heat pipe is inserted though the axle housing with a portion submersed in axle lubricant. Cooling fins are preferably disposed on the heat pipe both in the submersed region of the heat pipe and a portion external the housing. The heat pipe is preferably secured to and substantially accommodated by a removable cover plate which is in turn secured to the housing. The heat pipe includes an evaporative working fluid to promote heat transfer between the lubricant and external environment.

1 . An axle assembly for a motor vehicle, said axle assembly comprising: 
 an axle housing provided with a supply of liquid lubricant;    a cover removably secured to said housing; and    at least one a sealed heat transfer pipe mounted to said cover and, said heat transfer pipe including an heat-receiving zone, a heat-emitting zone and a heat transfer fluid that flows there between, wherein said fluid being evaporated in said heat-receiving zone and condensed in said heat-emitting zone to promote heat transfer between said lubricant and an external environment; wherein said heat-receiving zone is at least partially immersed in said lubricant when said cover is secured to said housing.    
   
   
       2 . The axle assembly according to  claim 1 , wherein said heat pipe is formed as a hollow loop-shaped pipe forming a continuous closed loop containing said heat transfer fluid.  
   
   
       3 . The assembly according to  claim 2 , wherein said loop shaped pipe include at least two elongated portions, a first elongated portion being disposed within said housing an substantially submerged in said lubricant, said loop shaped heat pipe being cast within a bolstered rear portion of said cover.  
   
   
       4 . The assembly according to  claim 3 , wherein a second elongated portion of said heat pipe is substantially embedded within a said bolstered portion of said cover, said bolstered portion having integrally formed fins directly exposed to said external environment.  
   
   
       5 . The assembly according to  claim 3 , wherein said heat pipe extends through said bolstered portion and includes a second elongated disposed external said housing and directly exposed to said external environment.  
   
   
       6 . The assembly according to  claim 5 , said heat pipe further includes a plurality of heat transfer fins affixed to said second elongated portion of said heat pipe.  
   
   
       7 . The assembly according to  claim 2  wherein said heat transfer fluid is sodium based solution.  
   
   
       8 . An axle assembly for a motor vehicle, said axle assembly comprising: 
 an axle housing containing gears to facilitate differential rotation between a pair of driven output gears, said housing containing a pool of liquid lubricant;    a cover removably secured to said housing to provide access to said gears within said housing; and    at least one a substantially sealed heat transfer pipe fixed to said cover and removable therewith relative to said housing, said heat transfer pipe including a heat-receiving zone, a heat-emitting zone and a working fluid, wherein said working fluid is evaporated in said heat-receiving zone and condensed in said heat-emitting zone to promote heat transfer between said lubricant and an external environment; wherein said heat-receiving zone is at least partially immersed in said lubricant when said cover is secured to said housing.    
   
   
       9 . The assembly according to  claim 8 , wherein at least one a sealed heat transfer pipe includes a pair of heat pipes each containing separate heat-receiving zones and heat-emitting zones, said pair of heat pipes being interconnected by a set of common heat dissipating fins.  
   
   
       10 . The assembly according to  claim 9  wherein said set of common heat dissipating fins includes a first set disposed proximate said heat-receiving zone and being substantially immersed in said lubricant.  
   
   
       11 . The assembly according to claim  19 , said heat pipe extends external said housing to said external environment and said heat pipe further including a second set of common heat dissipating fins disposed proximate said heat-emitting zone in said external environment.  
   
   
       12 . The assembly according to  claim 8 , wherein said cover contains an integrally formed reservoir in fluid communication with said pool of lubricant in said housing, said heat receiving zone of said heat pipe being substantially disposed within said reservoir.  
   
   
       13 . The assembly according to  claim 8 , wherein said working fluid is a water based fluid.  
   
   
       14 . The assembly according to  claim 8 , wherein said heat pipe further includes a wick member disposed within said heat pipe to promote transfer of working fluid from said heat receiving zone to said heat emitting zone through capillary action.  
   
   
       15 . The assembly according to  claim 14 , wherein said wick member is formed of a metal screen.