Heat exchanger and system for warming and cooling a fluid circulating in a housing

Abstract

A system for warming/cooling oil circulating within a power and torque transfer system of an automotive vehicle is disclosed. The system incorporates at least a first heat exchanger positioned between the inner wall of the outer housing and the outer surface of a gear forming part of the gear system enclosed within the housing, for instance a ring gear and/or pinion gear. The heat exchanger is generally formed as a single tubular member for conducting a first heat exchange fluid therethrough, the tubular member being curved to generally follow the curvature of the geometry of the inner wall of the housing and to fit within corresponding annular gaps. A second fluid channel is formed between the outer surface of the gear and the inner surface of the heat exchanger for bringing the oil into heat transfer relationship with the first heat exchanger fluid through rotation of the gear(s).

What is claimed is: 
     
         1 . A heat exchanger for warming or cooling a fluid circulating in a housing of a power and torque transfer system, the heat exchanger comprising:
 a tubular member having spaced apart walls, the tubular member being non-planar and generally arcuate in shape;   a first fluid passageway defined between said spaced apart walls;   a primary heat transfer surface defined by an exterior surface of one of said spaced apart walls of said tubular member;   an inlet opening in fluid communication with said first fluid passageway, the inlet opening formed on the spaced apart wall opposite to said primary heat transfer surface;   an outlet opening in fluid communication with said first fluid passageway, the outlet opening formed on the spaced apart wall opposite to said primary heat transfer surface; and   a second fluid passageway defined in part by said primary heat transfer surface.   
     
     
         2 . The heat exchanger as claimed in  claim 1 , wherein in said tubular member comprises a pair of mating non-planar generally arcuate plates, said tubular member being curved about an axis generally perpendicular to the longitudinal axis of said first fluid passageway. 
     
     
         3 . The heat exchanger as claimed in  claim 1 , wherein said inlet opening and said outlet opening are arranged at opposed ends of said tubular member. 
     
     
         4 . The heat exchanger as claimed in  claim 1 , further comprising:
 a turbulizer positioned in said first fluid passageway; and   a heat transfer augmenting device mounted on said primary heat transfer surface wherein said heat transfer augmenting device is a low density turbulizer or fin.   
     
     
         5 . A differential unit for an automotive vehicle, comprising:
 a gear system for transmitting torque and rotation to wheels of the automotive vehicle, the gear system comprising at least a ring gear and a pinion gear, the ring gear and pinion gear arranged in meshing relationship for rotational movement;   a housing enclosing said gear system;   a heat exchanger positioned interior the housing intermediate one of the ring gear or the pinion gear and an inner wall of the housing, the heat exchanger comprising:   a fluid passageway for the flow of a first fluid through the heat exchanger; and   a primary heat transfer surface arranged in spaced apart facing relationship to an outer surface of said one of the ring gear and pinion gear;   at least one axle oil passageway defined between said primary heat transfer surface and said outer surface of said one of the ring gear and pinion gear for bringing axle oil into heat transfer relationship with the first heat exchange fluid flowing through said heat exchanger;   wherein said axle oil is delivered to said at least one axle oil passageway through rotation of said pinion gear and said ring gear during operation of said gear system.   
     
     
         6 . The differential unit as claimed in  claim 5 , wherein:
 said heat exchanger is a first heat exchanger arranged intermediate said ring gear and said inner wall of said housing; and   a second heat exchanger arranged intermediate said pinion gear and said inner wall of said housing;   wherein the first heat exchanger is curved about the axis of rotation of the ring gear and wherein the second heat exchanger is curved about the axis of rotation of the pinion gear.   
     
     
         7 . The differential unit as claimed in  claim 5 , wherein said housing comprises a reservoir formed in a lower portion of said housing in relation to said ring gear for collecting axle oil. 
     
     
         8 . The differential unit as claimed in  claim 5 , wherein said pinion gear is mounted on a pinion shaft for rotation within said housing, said housing comprising a pinion shaft pocket formed in inner wall of said housing about said pinion shaft for the flow of axle oil around the pinion shaft proximal the pinion gear mounting. 
     
     
         9 . A method for warming or cooling a fluid circulating in a housing of a component of an automotive vehicle enclosing a gear system, the method comprising the steps of:
 providing at least a first heat exchanger in an annular gap formed between an outer surface of a gear in said gear system and an inner wall of the housing, the at least one heat exchanger defining a first fluid passageway between spaced apart walls and forming a second fluid passageway between the outer surface of the gear and one of said walls of said at least one heat exchanger;   supplying a first heat exchange fluid to said first fluid passageway of said at least one heat exchanger;   bringing a second heat exchange fluid into heat transfer relationship with said first heat exchange fluid in said at least one heat exchanger in said second fluid passageways through rotation of said gear system within said housing;   wherein said second heat exchange fluid is a fluid circulating within the housing of the component of the automotive vehicle.   
     
     
         10 . The method as claimed in  claim 9 , the gear system comprising a ring gear and a pinion gear in meshing relationship for rotation within the housing, wherein the first heat exchanger is arranged between the ring gear and the inner wall of the housing. 
     
     
         11 . The method of  claim 9 , the gear system comprising a ring gear and a pinion gear in meshing relationship for rotation within the housing, wherein the first heat exchanger is arranged between the pinion gear and the inner wall of the housing. 
     
     
         12 . The method of  claim 9 , wherein the component is a differential and the second heat exchange fluid is axle oil. 
     
     
         13 . The method of  claim 9  wherein the component is a manual transmission and the second heat exchange fluid is transmission oil. 
     
     
         14 . The method as claimed in  claim 9 , the gear system comprising a ring gear and a pinion gear in meshing relationship for rotation within the housing, wherein the first heat exchanger is arranged in relation to one of the ring gear and pinion gear, the method further comprising the step of:
 providing a second heat exchanger in a gap formed between the other of the ring gear or pinion gear and the inner wall of the housing, the second heat exchanger being oriented generally perpendicular to the first heat exchanger, the second heat exchanger defining a first fluid passageway between the pinion gear and one of said walls of said second heat exchanger;   supplying said first heat exchange fluid to said first fluid passageway of said second heat exchanger; and   bringing said second heat exchanger fluid into heat transfer relationship with said first fluid in said second heat exchanger in said second fluid passageway through rotation of said pinion gear and said ring gear.