US20060054411A1 - Heat pipe cooler for differential assembly - Google Patents
Heat pipe cooler for differential assembly Download PDFInfo
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- US20060054411A1 US20060054411A1 US11/184,070 US18407005A US2006054411A1 US 20060054411 A1 US20060054411 A1 US 20060054411A1 US 18407005 A US18407005 A US 18407005A US 2006054411 A1 US2006054411 A1 US 2006054411A1
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- Prior art keywords
- housing
- heat
- lubricant
- reservoir
- heat pipe
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0412—Cooling or heating; Control of temperature
Definitions
- the present invention relates to a heat pipe cooler for a differential assembly and particularly to an temperature sensitive valve for controlling flow of axle lubricant between the axle housing and reservoir.
- axles are lubricated by a reservoir of oil in the sump which is circulated by the moving components. This is known as splash lubrication.
- splash lubrication The operating temperature of a splash lubricated axle assembly or other torque transmission device is generally dependent on the torque being transmitted, the ambient temperature, the speed of rotation and airflow over the device.
- the operating temperature can be just above the ambient temperature to more than 200 degrees F. above ambient. Operating temperatures significantly above 250 degrees F. can begin to cause problems with the durability of the components in the axle as well as the lubricant itself. These temperatures are generally encountered at higher speeds and/or torques such as high speed highway driving or trailer towing. Therefore it is desirable to avoid these higher temperatures as much as possible. It is the intention of the present invention to minimize these high operating temperatures.
- a heat pipe including a closed tube having a heat exchange medium comprised of a plurality of fins.
- the aim underlying the present invention lies in providing an effective fluid lubricant cooling area that is readily utilizable, without significantly increasing the costs of production, the required space, and weight.
- the present invention is directed to a axle assembly for a motor vehicle having an axle housing provided with a supply of liquid lubricant.
- a cover is removably secured to the housing and at least one sealed heat transfer pipe is mounted to the cover which includes a heat-receiving zone, a heat-emitting zone and a heat transfer fluid that flows there between.
- the heat-receiving zone is at least partially immersed in the lubricant within a reseroiur portion of the housing.
- a temperature sensitive valve is provided to control the flow of the liquid lubricant between the reservoir and the housing.
- FIG. 1 is rear view of a differential cover plate with integral heat pipe assembly according to the present invention.
- FIG. 2 is a sectional view taken along lines 2 - 2 of FIG. 1 .
- FIG. 3 is rear view of a differential cover plate with integral heat pipe assembly according to an alternate embodiment of the present invention.
- FIG. 4 is a sectional view taken along lines 4 - 4 of FIG. 3 .
- FIG. 5 is a sectional view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention.
- FIG. 6 is a sectional view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention.
- FIG. 7 is a perspective view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention.
- FIG. 8 is a front exposed view of the embodiment of FIG. 7 .
- FIG. 9 is an enlarged partial exposed view of the embodiment of FIG. 8 .
- FIG. 10 is a sectional view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention.
- FIG. 11 is a perspective of an installed differential assembly employing the heat pipe of the present invention.
- FIG. 12 is a front view of a heat pipe secured to a differential housing according to an embodiment of the present invention.
- FIG. 13 is a side view of the embodiment depicted in FIG. 12 .
- FIG. 14 is a side view of an alternate embodiment of the present invention incorporating a temperature sensitive valve.
- FIG. 15 is a front exposed view of the temperature sensitive valve of FIG. 14 .
- the present invention is directed to a heat pipe assembly for cooling lubricating fluid in a differential axle assembly.
- an evaporative heat pipe assembly is employed to increase the amount of heat transfer from the lubricant to the external environment.
- the assembly includes a hermetically sealed heat pipe containing a working fluid which is secured to a removable cover.
- the working fluid is selected to be vaporizable and condensable within the working temperatures of the differential assembly.
- the purpose of the heat pipe is to decrease the temperature of the lubricating fluid in the axle assembly. If the temperature of the lubricant gets too high, the lubricant will break down decreasing viscosity and its ability to effectively lubricate the gear assembly.
- the present invention effectively maintains the fluid lubricant at acceptable operating temperatures.
- the heat pipe contains a working fluid such as water, or a sodium based fluid or other acceptable working fluids.
- a working fluid such as water, or a sodium based fluid or other acceptable working fluids.
- the working fluid collects at the bottom of the heat pipe due to the force of gravity.
- the bottom of the heat pipe is submersed in the pool of axle lubricant and causes the working fluid to vaporize (latent heat of vaporization) thus reducing the temperature of the lubricating oil.
- the vapor then travels up to a condensing portion where the vapor condenses giving up heat to an external environment.
- the condensed liquid then returns to the evaporative portion where the cycle continues.
- the arrangement increases the amount of heat that can be transferred from the axle lubricant.
- FIGS. 1-2 depict differential cover plate 1 with integral heat pipe assembly 3 .
- a hollow loop-shaped pipe 4 forming a continuous closed loop containing the heat transfer fluid 5 is integrally formed with a bolstered portion 7 of the cover 1 .
- the heat pipe is simply placed within a mold during casting of the cover plate 1 .
- the integral casting facilitates good contact between the heat pipe 4 and bolstered portion 7 to promote heat transfer there between as well as firmly position the heat pipe.
- the thick bolstered portion 7 is formed with heat dissipating fins 9 on an external surface to enhance heat transfer.
- a first elongated portion 11 of the heat pipe is disposed within the confines of the cover 1 and consequently within the axle housing. As can be seen in FIG.
- the heat pipe is below the level of the lubricant 13 , which lies just below access bore 14 , and thus the first elongated portion of the heat pipe remains submersed in the axle lubricant during operation of the axle assembly.
- a second elongated portion 12 remains substantially embedded within the bolstered portion 9 .
- the working fluid vaporizes in the first elongated portion 11 as it extracts heat from the hot lubricant. The vapor migrates to the second elongated portion where it condenses and gives off heat through the bolstered portion 7 to the external environment.
- the integral heat pipe and cover assembly provide a simple solution to increasing heat dissipation through the axle assembly without requiring modification to the axle assembly or remaining housing. Such an arrangement allows for easy retrofit applications to existing differential assemblies. The arrangement also allows for the heat pipe to be easily assembled with the cover away from the vehicle to which the axle is installed.
- FIGS. 3-4 represent an alternate embodiment of the present invention.
- heat pipe assembly 23 is integrally secured to the cover plate 21 .
- the heat pipe is preferably cast with the cover plate forming an integral connection between the heat pipe and cover plate.
- the heat pipe extends through a modified bolstered portion 27 of the cover plate 21 , such that the second elongated portion 31 is disposed external to the cover plate and axle housing.
- a plurality of heat dissipating fins 28 is secured to the second elongated portion of the heat pipe to promote heat transfer to the external environment.
- the remaining portions of the embodiment of FIGS. 3-4 remains nearly identical to that of the previously described embodiments of FIGS. 1-2 .
- the heat pipe assembly 3 , 23 may be filled with a sodium-based working fluid.
- the specific fluid and concentrations of soluble elements may be chosen to maintain a temperature to which the heat is to be transferred which is largely dependent on the desired operating temperature of the lubricating oil such as not to exceed 200 degrees. While this present embodiment does not include a capillary structure or wick, one may be incorporated to the extent it enhances the evaporative cycle.
- the working fluid must also be chosen to be compatible with the material of the heat pipe to avoid undesirable reactions.
- the heat pipe 3 , 23 and cover 1 may be made of aluminum, copper or stainless steel or other suitable materials.
- FIGS. 5-6 depict sectional views of additional embodiments of the present invention.
- a rear cover 101 is secured to a differential housing containing differential gearing to allow differential rotation between a pair (one shown) of output shafts 205 .
- a pinion gear 206 drives a ring gear 207 which in turn rotates a differntial case containing differential gears (schematically represented by reference numeral 208 ) as is commonly known in the art.
- the cover 101 is simply bolted to a rear potion of the housing as is conventional in the art.
- the cover plate 201 preferably contains an integrally formed reservoir 202 in fluid communication with pool of lubricant 213 in the housing 201 .
- the heat pipe assembly 203 contains a first evaporative end 211 disposed within the pool of lubricant 213 and includes a plurality of heat dissipating fins 211 a also submersed in the lubricant.
- the heat pipe extends through the cover plate 1 , reservoir 202 , to the external environment to condensing portion 212 which also includes a plurality of heat dissipating fins 212 a.
- the heat pipe assembly 203 also preferably includes a wick member 216 disposed within said heat pipe to promote transfer of working fluid from said evaporative heat receiving zone 211 to the condensing heat emitting zone 212 through capillary action.
- the wick member may be made for example of a metal mesh.
- FIG. 6 represents a slightly modified version of the embodiment depicted in FIG. 5 .
- the evaporative portion of the heat pipe 213 extends substantially vertical within the reservoir 202 as to substantially horizontal as the heat pipe 211 of the embodiment shown in FIG. 5 .
- FIGS. 7-9 two heat pipes 203 a, 203 b, are employed each containing separate evaporative cycles as in the previous embodiments.
- a first set of heat dissipating fins 412 a interconnects each of the heat pipes in the heat dissipating/condensing zone of the assembly.
- a second set of heat dissipating fins 411 a interconnects each of the heat pipes 403 a, 403 b in the heat receiving/evaporating zone of the assembly as shown in FIGS. 8-9 .
- the heat pipe, or envelope may be composed of a durable material able to withstand environmental corrosion while being lightweight. Aluminum, copper and even some types of plastics may be employed. In the embodiments shown in FIG. 1-4 the rear cover is preferably made of die cast aluminum and the heat pipe envelop made of aluminum with a sodium based working fluid contain therein. In the remaining embodiments metals such as aluminum, stainless steel or copper may be employed. Such metals provide sufficient strength to be able to contain high vapor pressures as higher working temperatures.
- the envelope may also be somewhat flexible, or bendable such as TygonTM tubing.
- the function of the wick is to transport the working fluid from the condenser to the evaporator via capillary action.
- the shape may be varied in form and can be made of various materials such as a metal screen. However, powdered metals, metal foams, sintered metals, felt type metals as well as some types of plastics or even glass my be employed so long as it is compatible with the working fluid and heat pipe envelope material.
- a wick may also be omitted forming a thermosyphon as in the embodiments of FIGS. 1-4 . It is finally noted that certain combinations of working fluid and envelopes which may produce non-condensable gasses should be avoided. These gases may result from a chemical reaction between the envelope and working fluid.
- FIGS. 1-13 are also believed to be within the spirit and scope of the present invention.
- the heat pipe may extend within the housing beyond the cover plate.
- the heat pipe may also extend substantially horizontally as it emerges from the cover plate as shown in FIG. 11 .
- FIGS. 14 to 15 represent another preferred embodiment incorporating a temperature sensitive valve 500 between the heat pipe and fluid reservoir in the cover. It is desirable to provide lubricant of sufficient viscosity to prevent frictional damage to mating gear teeth, yet be “flow-able” enough not to impede the efficiency of the gear mesh and create resistance.
- the proposed embodiment seeks to improve the concept of simply removing excessive heat, which is generated by fluid shear forces, by limiting the flow of oil to a heat sink source until needed. The contact restriction of oil to the heat sink will allow the axle to come up to operating temperature quickly to maintain operational efficiency. Once the desired temperature is achieved the thermostat (temperature sensitive valve), as described below, can create sufficient fluid communication to maintain the optimum oil temperature for various duty cycles. Thus the present arrangement will allow heat to build up more quickly to a desired temperature, then serve to remove excess heat. This is particularly desirable in cold environment to allow the lubricating oil to initially heat and increase efficiency of the differential gear assembly.
- the thermostat (temperature sensitive valve) assembly 500 comprises a rear plate 503 with an elongated opening 505 , preferably positioned such that the opening sits submerged below the oil level resident in the carrier housing.
- a front plate 501 with a corresponding slot 502 is pivotally affixed to a central pivot 507 such that the front plate 501 can be rotated relative to the rear plate 503 to create an orifice of varying size (from full open to closed) dependent on temperature of the oil.
- the central pivot 507 is affixed to the rear plate 503 and the front plate 501 is rotatably mounted thereon.
- a return spring 504 shown as a coiled arrangement, provides a biasing closing force such that the assembly prevents fluid communication with the heat exchanger unit until a predetermined temperature is reached.
- the opening baises the front plate 501 in the counter clockwise direction to eliminate alignment of the openings in the two plates and thus isolate the heat pipe from the housing reservoir.
- a thermostat tube 509 comprises a curved, tubular outer cylinder (affixed to the rear plate) and a piston 511 and curved actuator rod 513 (the free end affixed to the front plate 501 ) is submerged in the axle fluid.
- the thermostatic actuator is filled on one side of the piston with a thermally reactive wax 515 (or other material) which changes volume (and possibly state, i.e.
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- General Details Of Gearings (AREA)
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 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.
Description
- The present application is a Continuation-in-part of U.S. application Ser. No. 10/143,752 filed on May 14, 2002; and a Continuation-In Part application Ser. No. 10/794,419 filed on Mar. 8, 2004 of each of which are hereby incorporated herein by reference.
- 1. Field of the Invention
- The present invention relates to a heat pipe cooler for a differential assembly and particularly to an temperature sensitive valve for controlling flow of axle lubricant between the axle housing and reservoir.
- 2. Description of Related Art
- Typically axles are lubricated by a reservoir of oil in the sump which is circulated by the moving components. This is known as splash lubrication. The operating temperature of a splash lubricated axle assembly or other torque transmission device is generally dependent on the torque being transmitted, the ambient temperature, the speed of rotation and airflow over the device.
- The operating temperature can be just above the ambient temperature to more than 200 degrees F. above ambient. Operating temperatures significantly above 250 degrees F. can begin to cause problems with the durability of the components in the axle as well as the lubricant itself. These temperatures are generally encountered at higher speeds and/or torques such as high speed highway driving or trailer towing. Therefore it is desirable to avoid these higher temperatures as much as possible. It is the intention of the present invention to minimize these high operating temperatures.
- It is known to provide cooling conduits within an axle assembly in order to avoid high operating temperatures. These conduits are positioned about a majority of the differential assembly and contain a hydraulic fluid from another device which is capable of cooling the lubricant in the axle.
- It is also known to have a differential assembly with a heat pipe having heat-absorbing portions extending through an oil sump as well as externally disposed heat-transmitting devices.
- Additionally, it is know to have a heat pipe including a closed tube having a heat exchange medium comprised of a plurality of fins.
- Thus, the aim underlying the present invention lies in providing an effective fluid lubricant cooling area that is readily utilizable, without significantly increasing the costs of production, the required space, and weight.
- The present invention is directed to a axle assembly for a motor vehicle having an axle housing provided with a supply of liquid lubricant. A cover is removably secured to the housing and at least one sealed heat transfer pipe is mounted to the cover which includes a heat-receiving zone, a heat-emitting zone and a heat transfer fluid that flows there between. The heat-receiving zone is at least partially immersed in the lubricant within a reseroiur portion of the housing. A temperature sensitive valve is provided to control the flow of the liquid lubricant between the reservoir and the housing.
- A better understanding of the present invention will be had when reference is made to the accompanying drawings, wherein identical parts are identified by identical reference numbers and wherein:
-
FIG. 1 is rear view of a differential cover plate with integral heat pipe assembly according to the present invention. -
FIG. 2 is a sectional view taken along lines 2-2 ofFIG. 1 . -
FIG. 3 is rear view of a differential cover plate with integral heat pipe assembly according to an alternate embodiment of the present invention. -
FIG. 4 is a sectional view taken along lines 4-4 ofFIG. 3 . -
FIG. 5 is a sectional view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention. -
FIG. 6 is a sectional view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention. -
FIG. 7 is a perspective view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention. -
FIG. 8 is a front exposed view of the embodiment ofFIG. 7 . -
FIG. 9 is an enlarged partial exposed view of the embodiment ofFIG. 8 . -
FIG. 10 is a sectional view of a heat pipe secured to a differential cover according to an alternate embodiment of the present invention. -
FIG. 11 is a perspective of an installed differential assembly employing the heat pipe of the present invention. -
FIG. 12 is a front view of a heat pipe secured to a differential housing according to an embodiment of the present invention. -
FIG. 13 is a side view of the embodiment depicted inFIG. 12 . -
FIG. 14 is a side view of an alternate embodiment of the present invention incorporating a temperature sensitive valve. -
FIG. 15 is a front exposed view of the temperature sensitive valve ofFIG. 14 . - The present invention is directed to a heat pipe assembly for cooling lubricating fluid in a differential axle assembly. Preferably an evaporative heat pipe assembly is employed to increase the amount of heat transfer from the lubricant to the external environment. The assembly includes a hermetically sealed heat pipe containing a working fluid which is secured to a removable cover. The working fluid is selected to be vaporizable and condensable within the working temperatures of the differential assembly. The purpose of the heat pipe is to decrease the temperature of the lubricating fluid in the axle assembly. If the temperature of the lubricant gets too high, the lubricant will break down decreasing viscosity and its ability to effectively lubricate the gear assembly. The present invention effectively maintains the fluid lubricant at acceptable operating temperatures.
- The heat pipe contains a working fluid such as water, or a sodium based fluid or other acceptable working fluids. In liquid form, the working fluid collects at the bottom of the heat pipe due to the force of gravity. The bottom of the heat pipe is submersed in the pool of axle lubricant and causes the working fluid to vaporize (latent heat of vaporization) thus reducing the temperature of the lubricating oil. The vapor then travels up to a condensing portion where the vapor condenses giving up heat to an external environment. The condensed liquid then returns to the evaporative portion where the cycle continues. The arrangement increases the amount of heat that can be transferred from the axle lubricant. The structure of the preferred embodiments of the present invention will now be explained.
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FIGS. 1-2 depictdifferential cover plate 1 with integralheat pipe assembly 3. A hollow loop-shaped pipe 4 forming a continuous closed loop containing theheat transfer fluid 5 is integrally formed with a bolsteredportion 7 of thecover 1. The heat pipe is simply placed within a mold during casting of thecover plate 1. The integral casting facilitates good contact between theheat pipe 4 and bolsteredportion 7 to promote heat transfer there between as well as firmly position the heat pipe. The thick bolsteredportion 7 is formed withheat dissipating fins 9 on an external surface to enhance heat transfer. As can be seen a firstelongated portion 11 of the heat pipe is disposed within the confines of thecover 1 and consequently within the axle housing. As can be seen inFIG. 1 , the heat pipe is below the level of thelubricant 13, which lies just below access bore 14, and thus the first elongated portion of the heat pipe remains submersed in the axle lubricant during operation of the axle assembly. A secondelongated portion 12 remains substantially embedded within the bolsteredportion 9. The working fluid vaporizes in the firstelongated portion 11 as it extracts heat from the hot lubricant. The vapor migrates to the second elongated portion where it condenses and gives off heat through the bolsteredportion 7 to the external environment. As can be readily seen the integral heat pipe and cover assembly provide a simple solution to increasing heat dissipation through the axle assembly without requiring modification to the axle assembly or remaining housing. Such an arrangement allows for easy retrofit applications to existing differential assemblies. The arrangement also allows for the heat pipe to be easily assembled with the cover away from the vehicle to which the axle is installed. -
FIGS. 3-4 represent an alternate embodiment of the present invention. As in the previous embodiment,heat pipe assembly 23 is integrally secured to thecover plate 21. As in the previous embodiment the heat pipe is preferably cast with the cover plate forming an integral connection between the heat pipe and cover plate. According to this embodiment (FIGS. 3-4 ), the heat pipe extends through a modified bolsteredportion 27 of thecover plate 21, such that the secondelongated portion 31 is disposed external to the cover plate and axle housing. A plurality ofheat dissipating fins 28 is secured to the second elongated portion of the heat pipe to promote heat transfer to the external environment. The remaining portions of the embodiment ofFIGS. 3-4 remains nearly identical to that of the previously described embodiments ofFIGS. 1-2 . - The
heat pipe assembly heat pipe cover 1, may be made of aluminum, copper or stainless steel or other suitable materials. -
FIGS. 5-6 depict sectional views of additional embodiments of the present invention. Referring toFIG. 5 , arear cover 101 is secured to a differential housing containing differential gearing to allow differential rotation between a pair (one shown) ofoutput shafts 205. A pinion gear 206 drives a ring gear 207 which in turn rotates a differntial case containing differential gears (schematically represented by reference numeral 208) as is commonly known in the art. Thecover 101 is simply bolted to a rear potion of the housing as is conventional in the art. Thecover plate 201 preferably contains an integrally formedreservoir 202 in fluid communication with pool oflubricant 213 in thehousing 201. Theheat pipe assembly 203 contains a firstevaporative end 211 disposed within the pool oflubricant 213 and includes a plurality ofheat dissipating fins 211 a also submersed in the lubricant. The heat pipe extends through thecover plate 1,reservoir 202, to the external environment to condensingportion 212 which also includes a plurality ofheat dissipating fins 212 a. Theheat pipe assembly 203 also preferably includes awick member 216 disposed within said heat pipe to promote transfer of working fluid from said evaporativeheat receiving zone 211 to the condensingheat emitting zone 212 through capillary action. The wick member may be made for example of a metal mesh. -
FIG. 6 represents a slightly modified version of the embodiment depicted inFIG. 5 . In this embodiment, the evaporative portion of theheat pipe 213 extends substantially vertical within thereservoir 202 as to substantially horizontal as theheat pipe 211 of the embodiment shown inFIG. 5 . - In the embodiments of
FIGS. 7-9 two heat pipes 203 a, 203 b, are employed each containing separate evaporative cycles as in the previous embodiments. However, a first set of heat dissipating fins 412 a interconnects each of the heat pipes in the heat dissipating/condensing zone of the assembly. A second set ofheat dissipating fins 411 a interconnects each of theheat pipes 403 a, 403 b in the heat receiving/evaporating zone of the assembly as shown inFIGS. 8-9 . - As previously indicated the specific materials may be selected based on the material specified for the cover plate and operating temperature of the lubricating fluid of the axle assembly. The heat pipe, or envelope may be composed of a durable material able to withstand environmental corrosion while being lightweight. Aluminum, copper and even some types of plastics may be employed. In the embodiments shown in
FIG. 1-4 the rear cover is preferably made of die cast aluminum and the heat pipe envelop made of aluminum with a sodium based working fluid contain therein. In the remaining embodiments metals such as aluminum, stainless steel or copper may be employed. Such metals provide sufficient strength to be able to contain high vapor pressures as higher working temperatures. The envelope may also be somewhat flexible, or bendable such as Tygon™ tubing. The function of the wick is to transport the working fluid from the condenser to the evaporator via capillary action. The shape may be varied in form and can be made of various materials such as a metal screen. However, powdered metals, metal foams, sintered metals, felt type metals as well as some types of plastics or even glass my be employed so long as it is compatible with the working fluid and heat pipe envelope material. A wick may also be omitted forming a thermosyphon as in the embodiments ofFIGS. 1-4 . It is finally noted that certain combinations of working fluid and envelopes which may produce non-condensable gasses should be avoided. These gases may result from a chemical reaction between the envelope and working fluid. For example, an aluminum envelope and water will produce Al2O3 and hydrogen gas. Excessive accumulation of non-condensable gasses will cause the heat pipe to fail. However, it is well within the knowledge of one of ordinarily skill in the art to avoid such unacceptable combinations as such are well documented in the art. - While the foregoing invention has been shown and described with reference to a preferred embodiment, it will be understood by those possessing skill in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. For example additional exemplary embodiments are shown in
FIGS. 1-13 which are also believed to be within the spirit and scope of the present invention. For example, referring toFIG. 10 , the heat pipe may extend within the housing beyond the cover plate. The heat pipe may also extend substantially horizontally as it emerges from the cover plate as shown inFIG. 11 . - FIGS. 14 to 15 represent another preferred embodiment incorporating a temperature
sensitive valve 500 between the heat pipe and fluid reservoir in the cover. It is desirable to provide lubricant of sufficient viscosity to prevent frictional damage to mating gear teeth, yet be “flow-able” enough not to impede the efficiency of the gear mesh and create resistance. The proposed embodiment seeks to improve the concept of simply removing excessive heat, which is generated by fluid shear forces, by limiting the flow of oil to a heat sink source until needed. The contact restriction of oil to the heat sink will allow the axle to come up to operating temperature quickly to maintain operational efficiency. Once the desired temperature is achieved the thermostat (temperature sensitive valve), as described below, can create sufficient fluid communication to maintain the optimum oil temperature for various duty cycles. Thus the present arrangement will allow heat to build up more quickly to a desired temperature, then serve to remove excess heat. This is particularly desirable in cold environment to allow the lubricating oil to initially heat and increase efficiency of the differential gear assembly. - The thermostat (temperature sensitive valve)
assembly 500 comprises a rear plate 503 with anelongated opening 505, preferably positioned such that the opening sits submerged below the oil level resident in the carrier housing. Afront plate 501 with acorresponding slot 502 is pivotally affixed to acentral pivot 507 such that thefront plate 501 can be rotated relative to the rear plate 503 to create an orifice of varying size (from full open to closed) dependent on temperature of the oil. Thecentral pivot 507 is affixed to the rear plate 503 and thefront plate 501 is rotatably mounted thereon. Areturn spring 504, shown as a coiled arrangement, provides a biasing closing force such that the assembly prevents fluid communication with the heat exchanger unit until a predetermined temperature is reached. In the present arrangement the opening baises thefront plate 501 in the counter clockwise direction to eliminate alignment of the openings in the two plates and thus isolate the heat pipe from the housing reservoir. Athermostat tube 509 comprises a curved, tubular outer cylinder (affixed to the rear plate) and apiston 511 and curved actuator rod 513 (the free end affixed to the front plate 501) is submerged in the axle fluid. The thermostatic actuator is filled on one side of the piston with a thermally reactive wax 515 (or other material) which changes volume (and possibly state, i.e. solid to liquid) based on a desired temperature of the axle lubricant. As the fluid heats up, thewax volume 515 increases which extends thepiston 511 within the cylinder and thusly actuates thefront plate 501 clockwise relative to the rear plate 503. Such rotation aligns the slotted openings so that the hot fluid comes into contact with theheat exchanger unit 211 a. As the fluid temperature increases, the size of the aligned opening will increase thus allowing ever increasing flow of lubricant intorear reservoir 202 which in the present embodiment may be isolated from the remaining portion of the axle assembly reservoir during cold operation. - The described embodiments as well as modifications thereto are all believed to be within the spirit and scope of the present invention and are defined by the following claims.
Claims (5)
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.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/184,070 US20060054411A1 (en) | 2002-05-14 | 2005-07-19 | Heat pipe cooler for differential assembly |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/143,752 US6830096B1 (en) | 2002-05-14 | 2002-05-14 | Heat pipe for differential assembly |
US10/794,419 US20050126749A1 (en) | 2002-05-14 | 2004-03-08 | Heat pipe cooler for differential assembly |
US11/184,070 US20060054411A1 (en) | 2002-05-14 | 2005-07-19 | Heat pipe cooler for differential assembly |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/143,752 Continuation-In-Part US6830096B1 (en) | 2002-05-14 | 2002-05-14 | Heat pipe for differential assembly |
US10/794,419 Continuation-In-Part US20050126749A1 (en) | 2002-05-14 | 2004-03-08 | Heat pipe cooler for differential assembly |
Publications (1)
Publication Number | Publication Date |
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US20060054411A1 true US20060054411A1 (en) | 2006-03-16 |
Family
ID=36032689
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/184,070 Abandoned US20060054411A1 (en) | 2002-05-14 | 2005-07-19 | Heat pipe cooler for differential assembly |
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US (1) | US20060054411A1 (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080312023A1 (en) * | 2007-06-18 | 2008-12-18 | Beutler Kevin R | Vehicle driveline component having heat sink for increased heat rejection capabilities |
US20110082001A1 (en) * | 2007-06-18 | 2011-04-07 | American Axle & Manufacturing, Inc. | Vehicle driveline component having heat sink for increased heat rejection capabilities |
CN102563001A (en) * | 2011-12-20 | 2012-07-11 | 大连熵立得传热技术有限公司 | Hydrodynamic coupler with heat pipe type radiating assembly |
US8657716B1 (en) | 2012-09-13 | 2014-02-25 | American Axle & Manufacturing, Inc. | Drive train component with structural cover |
WO2014164251A1 (en) * | 2013-03-11 | 2014-10-09 | Dana Automotive Systems Group, Llc | Differential carrier temperature sensing method |
USD741913S1 (en) * | 2013-06-05 | 2015-10-27 | Eaton Corporation | Integrated electronic limited slip rear wheel drive axle cover |
US20170097086A1 (en) * | 2015-10-02 | 2017-04-06 | Toyota Jidosha Kabushiki Kaisha | Cooling system for power transmission unit |
USD798906S1 (en) * | 2015-11-02 | 2017-10-03 | Omix-Ada, Inc. | Vehicle differential cover |
US9777824B2 (en) * | 2014-11-07 | 2017-10-03 | Modine Manufacturing Company | Cooled gear housing assembly |
US10151380B2 (en) * | 2015-09-29 | 2018-12-11 | Mazda Motor Corporation | Transmission and manufacturing method of the same |
US10682884B1 (en) * | 2019-06-26 | 2020-06-16 | Caterpillar Inc. | Axle differential guard |
US11181181B1 (en) | 2020-09-03 | 2021-11-23 | Ford Global Technologies, Llc | Differential thermal management system |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6830096B1 (en) * | 2002-05-14 | 2004-12-14 | Torque-Traction Technologies, Inc. | Heat pipe for differential assembly |
US20050126749A1 (en) * | 2002-05-14 | 2005-06-16 | Matti Assil I. | Heat pipe cooler for differential assembly |
-
2005
- 2005-07-19 US US11/184,070 patent/US20060054411A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6830096B1 (en) * | 2002-05-14 | 2004-12-14 | Torque-Traction Technologies, Inc. | Heat pipe for differential assembly |
US20050126749A1 (en) * | 2002-05-14 | 2005-06-16 | Matti Assil I. | Heat pipe cooler for differential assembly |
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080312023A1 (en) * | 2007-06-18 | 2008-12-18 | Beutler Kevin R | Vehicle driveline component having heat sink for increased heat rejection capabilities |
US7819769B2 (en) * | 2007-06-18 | 2010-10-26 | American Axle & Manufacturing, Inc. | Vehicle driveline component having heat sink for increased heat rejection capabilities |
US20110082001A1 (en) * | 2007-06-18 | 2011-04-07 | American Axle & Manufacturing, Inc. | Vehicle driveline component having heat sink for increased heat rejection capabilities |
US8585526B2 (en) | 2007-06-18 | 2013-11-19 | American Axle & Manufacturing, Inc. | Vehicle driveline component having heat sink for increased heat rejection capabilities |
CN102563001A (en) * | 2011-12-20 | 2012-07-11 | 大连熵立得传热技术有限公司 | Hydrodynamic coupler with heat pipe type radiating assembly |
US8657716B1 (en) | 2012-09-13 | 2014-02-25 | American Axle & Manufacturing, Inc. | Drive train component with structural cover |
US9334950B2 (en) | 2013-03-11 | 2016-05-10 | Dana Automotive Systems Group, Llc | Differential carrier electronics package |
WO2014164251A1 (en) * | 2013-03-11 | 2014-10-09 | Dana Automotive Systems Group, Llc | Differential carrier temperature sensing method |
US9651142B2 (en) | 2013-03-11 | 2017-05-16 | Dana Automotive Systems Group, Llc | Differential carrier temperature sensing method |
US9976644B2 (en) | 2013-03-11 | 2018-05-22 | Dana Automotive Systems Group, Llc | Differential carrier temperature sensing method |
USD741913S1 (en) * | 2013-06-05 | 2015-10-27 | Eaton Corporation | Integrated electronic limited slip rear wheel drive axle cover |
US9777824B2 (en) * | 2014-11-07 | 2017-10-03 | Modine Manufacturing Company | Cooled gear housing assembly |
US10151380B2 (en) * | 2015-09-29 | 2018-12-11 | Mazda Motor Corporation | Transmission and manufacturing method of the same |
US20170097086A1 (en) * | 2015-10-02 | 2017-04-06 | Toyota Jidosha Kabushiki Kaisha | Cooling system for power transmission unit |
US10458533B2 (en) * | 2015-10-02 | 2019-10-29 | Toyota Jidosha Kabushiki Kaisha | Cooling system for power transmission unit |
USD798906S1 (en) * | 2015-11-02 | 2017-10-03 | Omix-Ada, Inc. | Vehicle differential cover |
US10682884B1 (en) * | 2019-06-26 | 2020-06-16 | Caterpillar Inc. | Axle differential guard |
US11181181B1 (en) | 2020-09-03 | 2021-11-23 | Ford Global Technologies, Llc | Differential thermal management system |
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Owner name: TORQUE-TRACTION TECHNOLOGIES, INC., OHIO Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FETT, GREGORY ALLEN;RUNSTADLER, TIMOTHY WILLIAM;KRUEGER, DAVID ALLEN;AND OTHERS;REEL/FRAME:016840/0329;SIGNING DATES FROM 20050720 TO 20051126 |
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STCB | Information on status: application discontinuation |
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