Heat pipe cooler for differential assembly
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 a reservoir portion of the 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. A temperatures sensitive valve provided to inhibit flow of the axle lubricant between a reservoir and the remaining portion of the axle housing.
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;
wherein said cover includes a reservoir formed therewith, said heat-receiving zone of said heat pipe being at least partially disposed within said reservoir, said assembly further comprising:
a temperatures sensitive valve provided to inhibit flow of said liquid lubricant between said reservoir and said housing.
2 . The assembly according to claim 1 , wherein said temperature sensitive valve is biased in a closed position to isolate said liquid lubricant within said housing from said reservoir during cold operation and progressively opens as said temperature of said liquid lubricant within said housing increases.
3 . The assembly according to claim 2 , wherein said temperature sensitive valve comprises:
a rear plate having a first hole;
a second plate having a second hole rotationally mounted relative to said real plate between an open position whereby said first and second holes are at least partially aligned such that said liquid lubricant may flow between said housing and said reservoir and a closed position where said first and said holes are discretely positioned in an unaligned fashion thereby substantially isolating lubricant between said reservoir and said housing, and
a biasing member biasing said front plate in said closed position.
4 . The assembly according to claim 3 , wherein said biasing member comprises:
a piston disposed within a tubular cylinder filed with a thermally reactive wax, and
an actuator rod connecting said piston to said front plate wherein when said lubricant within said housing fluid heats up the volume of the thermally reactive wax increases which displaces the piston within the cylinder and consequently actuates the front plate towards said open position whereby as the lubricant temperature increases, the size of the aligned opening will progressively increase thus allowing ever increasing flow of lubricant into rear reservoir.
5 . 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 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; wherein said cover includes a reservoir integrally formed therewith, said heat-receiving zone of said heat pipe being at least partially disposed within said reservoir, said assembly further comprising:
a temperatures sensitive valve provided to inhibit flow of said liquid lubricant between said reservoir and said housing; said temperature sensitive valve being biased in a closed position to isolate said liquid lubricant within said housing from said reservoir during cold operation and progressively opens as said temperature of said liquid lubricant within said housing increases; said temperature sensitive valve including;
a rear plate having a first hole;
a second plate having a second hole rotationally mounted relative to said rear plate between an open position whereby said first and second holes are at least partially aligned such that said liquid lubricant may flow between said housing and said reservoir and a closed position where said first and said holes are discretely positioned in an unaligned fashion thereby substantially isolating lubricant between said reservoir and said housing, and
a biasing member biasing said front plate in said closed position, said biasing member including;
a piston disposed within a tubular cylinder filed with a thermally reactive wax, and
an actuator rod connecting said piston to said front plate wherein when said lubricant within said housing fluid heats up the volume of the thermally reactive wax increases which displaces the piston within the cylinder and consequently actuates the front plate towards said open position whereby as the lubricant temperature increases, the size of the aligned opening will progressively increase thus allowing ever increasing flow of lubricant into rear reservoir.