JP2009281446A - Axle temperature controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller adjusting and controlling a temperature of vehicle axle assembly. <P>SOLUTION: The controller is characterized in that a conduit is connected to a heating/cooling fluid circuit of internal combustion engine to keep heating/cooling liquid circulated to axle assembly through an inlet conduit, which passes through a wall of the axle assembly and terminates at a heat exchanger, in that the heat exchanger is arranged beneath a stagnant spot formed by a lubricating liquid of the axle assembly to make coolant heat the lubricating liquid during vehicle first stage operation and low working speed at the time of starting condition at low temperature, and cool the lubricating liquid when the vehicle operates at high temperature and high speed, and in that the heating/cooling liquid is returned to the cooling liquid circuit through an outlet conduit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an axle assembly or other torque transmission device that is lubricated by splashing fluid. More specifically, the present invention relates to an apparatus for improving axle efficiency by providing a heating medium in an axle assembly or torque transmission device.

The efficiency of the axle depends in part on the lubrication temperature of the axle. Typically, the axle is lubricated by oil stored in a sump that is circulated by moving components. This is known as splash oiling. As the lubricating oil temperature increases, the efficiency of the axle also increases. This is mainly true at low torque levels, as shown in the table below.
Axle efficiency (output torque / input torque)
Output torque at 35 mph (ft-lbs)
Axle sump temperature 100 150 300
100 degrees F 85.1% 89.2% 93.6%
175 degrees F 93.8% 95.1% 96.5%
250 degrees F 94.0% 94.8% 95.6%

  The above data shows that efficiencies between 2.0 and 8.9 percent are obtained when operating between 175 and 250 degrees F for 100 degrees F. The biggest gain is at low torque levels. The gain in efficiency is mainly attributed to a natural decrease in the viscosity of the lubricating oil with increasing temperature. The operating temperature of a splash lubricated axle assembly or other torque transmission device generally depends on the torque transmitted, the ambient temperature, the rotational speed, and the airflow flowing over the device. The operating temperature may be a temperature slightly above ambient temperature and above 200 degrees Fahrenheit. Operating temperatures well above 250 degrees F may begin to cause problems with the durability of the axle components and the lubricating oil itself. These temperatures generally occur at higher speeds and / or higher torques such as highway driving or trailer towing. Therefore, it is desirable to avoid such temperatures as much as possible. Low operating temperatures generally do not raise durability concerns, but as mentioned above, operating temperatures below 175 degrees F will cause lower efficiency and greater fuel consumption. Such low operating temperatures generally occur at lower speeds and / or torques, such as slow street rides. The intent of the present invention is to minimize these low operating temperatures.

  In order to avoid high operating temperatures, it is known to provide cooling conduits in the axle assembly. This conduit is placed around most differential assemblies and contains hydraulic fluid from another device that can cool the axle lubricant.

  It is also known to have a gear-driven cooling system that includes a heat exchanger having a loop of piping in which a plurality of fins are disposed that absorb heat and break oil droplets that are thrown during operation.

  It is further known to have a transmission cooling system that circulates engine coolant from a radiator through a heat exchanger located in the transmission sump. The coolant is at the lowest possible temperature in the engine cooling system and is drawn from the radiator to warm up at the end, which is most efficient for cooling the transmission.

  It is also known to have a heating system for a vehicle exhaust gas warm-up system that circulates engine coolant through a heat exchanger located inside the exhaust system. This is intended to warm the engine coolant more quickly and increase engine efficiency during the warm-up phase. Efficiency is reduced at this stage because fuel atomization is poor and more fuel is needed for the air mixture. When the engine is warmed up, the temperature is controlled by a thermostat and becomes relatively constant. The system can also warm engine oil, transmission oil, or axle oil by using a pump to circulate the oil through a heat exchanger located in the exhaust system. In the case of transmission and axle, a separate pump is required to circulate the oil through the heat exchanger, but the engine already has an existing pump. Furthermore, at very low ambient temperatures, the oil will not easily flow through the conduit to the heat exchanger until it is heated by friction and heat from the exhaust system.

  The present invention provides heat to the shaft assembly or other torque transfer device without the need for the lubricant to be pumped to another heat exchanger outside the axle. Also, typically, the temperature of the lubricating oil is maintained at about 200 degrees F to increase the efficiency of the axle under conditions where the axle will operate at temperatures below about 175 degrees F.

  The present invention achieves the same or better results than those described above.

  Accordingly, an advantage of the present invention is the provision of a temperature regulator for a differential assembly that uses coolant from the automotive engine area. Preferably, the coolant is drawn directly from the engine block to quickly provide a heating effect to the axle assembly. The present invention heats a splash-lubricated axle assembly or other similar torque transmission device to reduce or eliminate lower portions of the normal operating temperature range to maximize efficiency. Is intended.

  In a preferred embodiment, coolant from an internal combustion engine or other power source is located at the bottom of the jacketed cover plate with a hollow passage attached to the axle carrier or the axle carrier where the lubricating oil accumulates. Circulated through a suitable heat exchanger. Ideally, this cover plate configuration maximizes heat exchange to the lubricant inside the axle assembly. In the case of an internal combustion engine, the coolant is pumped by the engine's water pump and pulled from the engine block behind the thermostat where it is heated as quickly as possible to about 200 degrees F. Logic controllers and valves may be used to prevent coolant from flowing to the axle when needed for more important purposes such as defrosting windows in the cabin. The present invention also cools the axle when the operating temperature tends to rise above the temperature of the coolant.

  In one embodiment, the power plant coolant is circulated through a hollow passage cast or fabricated in the wall of the axle carrier cover. Heated air from the power section is directed through suitable piping and flows over or around the axle carrier. A heat pipe is used to transfer heat from the power section to the axle. Exhaust gas may be circulated through a hollow passage cast or fabricated in the axle unit wall.

  Yet another advantage of the present invention is to provide an apparatus for heating and / or cooling an automobile axle assembly, the axle assembly including a housing defining a chamber in which lubricating oil is contained; And a differential assembly disposed therein, the apparatus comprising a heat exchanger disposed in the chamber, the heat exchanger having an inlet for fluid connection to a cooling fluid circuit of the internal combustion engine And a fluid conduit having an outlet.

  Another embodiment circulates the coolant through a suitable heat exchanger located in the cavity of the axle pinion bearing, in which the lubricant splashes or flows over the axle carrier. Lubricant accumulates or coolant is circulated through a suitable heat exchanger located inside.

  Hot exhaust gas from an internal combustion engine or other power source is circulated through a jacketed cover plate with a hollow passage attached to an axle carrier in yet another embodiment. Ideally, the cover plate configuration maximizes heat transfer to the lubricating oil inside the axle assembly. Logic controllers and valves may be used to control the exhaust flow to prevent the lubricant temperature from becoming excessive.

  The exhaust gas may also be circulated through a hollow passage in the axle carrier wall.

  The exhaust gas may also be circulated through a suitable heat exchanger located at the bottom of the carrier where the lubricating oil accumulates.

  The exhaust gas may also be circulated through a suitable heat exchanger located in the pinion bearing cavity where the lubricating oil accumulates.

  The exhaust gas may also be circulated through a suitable heat exchanger located inside the carrier where the lubricant splashes or flows over.

  In another embodiment, the electrical heating element is placed inside a hollow passage cast or fabricated in an axle cover plate attached to the axle carrier. Ideally, the cover plate configuration maximizes heat transfer to the lubricating oil inside the axle assembly. In order to keep the lubricant at the proper temperature, a logic controller may be used to control the power to the heating element.

  The electrical heating element may also be placed inside a hollow passage cast or fabricated in the axle carrier wall.

  The electrical heating element may also be located at the bottom of the carrier where the lubricating oil accumulates.

  The electric heating element may also be disposed in the cavity of the pinion bearing in which the lubricating oil accumulates.

  The electrical heating element may also be located inside the axle carrier where the lubricant splashes or flows over.

  In another embodiment, air heated by a power section or power source is passed through appropriate piping and flows over or around the axle carrier. Valves and fans may be used to control air flow and axle temperature.

  In another embodiment, heat pipes are used to transfer heat from the power source or power source to the axle assembly. This works best when the power unit or power source is very close to the axle assembly and the axle is not moving relative to the power unit or power source during operation. This is true for the front independent axle configuration. In this case, the heat pipe will try to bring the axle and power section or power source to the same temperature.

  These advantages and other novel features of the present invention will become apparent in the following detailed description of the invention when considered in conjunction with the accompanying drawings.

  A better understanding of the present invention will be obtained when reference is made to the accompanying drawings in which like parts are designated by like reference numerals.

  The features of the present invention described above include heating in the engine block to first warm the lubricating oil in the axle assembly in a cold start environment and then cool the axle assembly when and when it begins to overheat. Provide a temperature regulating device (ie heating and / or cooling means) for the axle assembly using a cooling fluid.

  The axle assembly heating and cooling system of the present invention requires an internal, preferably integral, engine forced liquid cooling system located in the engine block 8. The engine forced liquid cooling system includes an engine coolant and a fluid conduit 14 connected to the inlet connection of the internal axle assembly heat exchanger 18, and one end to the outlet connection of the heat exchanger 18 of the internal axle assembly. For both of the fluid conduits 16 connected to each other. Thus, the heat exchanger of the inner axle assembly is connected in series to the pressurized liquid cooling system of the vehicle that defines the engine cooling fluid circuit. Vehicle coolant cooling fluid also flows through the axle assembly.

  A vehicle torque transmission device, such as an axle assembly, requires a lubricant 37 so that the movable gear in the assembly can function properly. The temperature of the lubricating fluid 37 in the axle assembly 20 varies depending on a number of conditions, including but not limited to ambient temperature, speed, torque, and the like. During initial vehicle drive conditions and slower operation, the axle assembly 20 is relatively cold, resulting in inefficient operation. Usually, the lubricating liquid 37 is heated by friction applied from the movable gear. When the vehicle is operating at high speed, the friction between the gears of the axle assembly 20 generates significant heat. It has been discovered that maintaining the lubricant 37 within a temperature range of 150-250 degrees Fahrenheit results in the most efficient results from the axle assembly 20, such as increased component life. The ideal operating temperature for the axle assembly is approximately 200 degrees Fahrenheit.

  During cold start conditions, heat is provided to the axle assembly 20 by circulating coolant directly from the power plant or engine through a heat exchanger 18 disposed within the axle assembly 20. With reference to FIG. 1, a pair of fluid conduits 14, 16 are securely attached to the engine 10 to allow coolant to be supplied to a heat exchanger disposed within the axle assembly 20. The fluid inlet conduit 14 supplies coolant from the engine block 8 along the vehicle body to the axle assembly 20. Similarly, the fluid outlet conduit 16 serves as a return pipe for the coolant returning from the axle assembly 20 to the engine or radiator in the engine block 8. In the preferred embodiment, the coolant is drawn directly from the engine to deliver heat to the axle assembly 20 most efficiently and quickly.

  Alternatively, the inlet and outlet conduits that carry the coolant from and to the engine radiator are formed as a single tube. Two channels are formed in the tube, one channel supplies coolant to the axle assembly and the other channel serves to return coolant from the axle assembly to the engine.

  As best seen in FIGS. 1 and 2, two conduits 14, 16 run next to the frame over the entire length of the vehicle 12 from the engine block 8 to the axle assembly 20. The conduits 14, 16 follow a serpentine path along the vehicle chassis from the engine block 8 to the axle assembly 20. During manufacture, the vehicle body may be molded with a concave recess to provide additional protection to the conduit. The conduits 14, 16 are secured to the vehicle by means known to those skilled in the art. Although not absolutely necessary, by insulating the conduits 14, 16, the coolant temperature is maintained and heat loss from the engine block 8 to the axle assembly 20 is minimized.

  The axle assembly 20 is described below. Referring to FIG. 3, an axle assembly 20 of a vehicle 12 incorporating features of the present invention therein is shown. The axle assembly 20 includes a housing 22. The housing 22 further includes an inlet passage 24 and an outlet passage 26.

  The housing 22 also includes a drive shaft opening (not shown) and axle openings 30,32. The housing 22 further includes a chamber 36 defined by the housing. A differential assembly 38 is mounted in the chamber 36 of the housing 22 in a well known manner. The housing has a pair of passages for receiving inlet and outlet conduits 14,16.

  As best seen in FIG. 3, the conduits 14, 16 are inserted through the passages 24, 26 on the outer surface of the housing 22 so that a hermetic seal is created between the chamber 36 and the chamber of the external environment. Fixed to. The inlet and outlet conduits 14, 16 are disposed along the inner surface of the housing 22. The lubricating fluid 37 of the axle assembly is disposed in the housing 22 to fill the chamber 36, and the level of the lubricating liquid 37 is approximately half of the free space in the chamber 36 after insertion of the differential assembly 38. is there. The lubricating liquid 37 accumulates in the chamber 36 at the bottom of the housing 22.

  In another embodiment best seen in FIG. 4, an inlet conduit 414 and an outlet conduit 416 are inserted into a passage located at the bottom of the housing 422. In this embodiment, both inlet and outlet conduits 414, 416 and heat exchanger 418 are all located below the reservoir of lubricating liquid 437.

  In yet another embodiment, the inlet conduit 514 enters the axle assembly as best seen in FIG. Inlet conduit 514 is disposed adjacent to the inner wall of axle assembly 520. As can be seen in FIG. 5, the heat exchanger 518 is positioned below the reservoir of lubricating liquid 518 and an outlet conduit 516 passes through the housing 522.

  In yet another alternative embodiment, as best seen in FIG. 6, the inlet conduit 614 enters through a passage in the upper half of the axle assembly cover 650 for the carrier or housing 622. The outlet conduit 616 exits the axle assembly 620 through a similar passage in the lower half of the axle assembly cover 650. Next, the axle assembly cover 650 is secured to the housing 622. The heat exchanger 618 is disposed in the chamber 636 as can be seen in FIG. The heat exchanger 618 also has cooling fins 619 along the body of the heat exchanger 618. Lubricant 637 is splashed in chamber 636 while differential assembly 638 rotates. When the lubricating liquid 637 comes into contact with the cooling fins 619, the lubricating liquid 637 is cooled or heated depending on the temperature of the cooling fins 619 as adjusted by the fluid flowing through the heat exchanger 618.

  Referring now to FIG. 7, in yet another embodiment, coolant is circulated through a passage 718 that is cast or made along the outer surface of the axle housing 722. The housing 722 is made or cast with an inlet connection 714 disposed near the front end of the housing 722. The outlet connection portion 716 is disposed in the vicinity of an axle assembly cover (not shown). The inlet tube is secured to the inlet connection 714 so that coolant can flow from the engine through the inlet tube. The coolant fills the passage 718 in the housing 722. The coolant cools or heats the axle housing 722 depending on the relative temperature between the coolant and the housing 722. The temperature of the lubricating liquid is adjusted by the temperature of the housing 722.

  Similarly, the adjustment of the temperature within the axle assembly may be further adjusted by passages cast or fabricated in the axle assembly cover 850, as best seen in FIG. The axle assembly cover again has an inlet connection 814 and an outlet connection 816. A conduit for supplying coolant from the engine connects with the inlet connection 814. The coolant flows through the axle assembly cover 850 via the passage 818. The coolant warms or cools the axle assembly cover 850 and then similarly affects the temperature of the lubricating fluid in the assembly.

  The concepts described in the embodiment of FIGS. 7 and 8 may be partially combined to create the embodiment best seen by FIG. In this embodiment, the passage 918 is cast or fabricated within both the axle assembly housing 922 and the axle assembly cover 950. When cover 950 is mated with housing 922, a single passage 918 is formed in both elements. The housing 922 includes an inlet connection portion 914 and an outlet connection portion 916 that are disposed at the front end portion of the housing 922 so as to face each other. The coolant enters through a conduit attached to the inlet connection 914 and fills the passage 918. The temperature of the axle assembly 920 is adjusted by the coolant temperature as it enters the passage 918.

  Referring again to FIG. 3, the inlet conduit 14 carries the coolant to the heat exchanger 18. The heat exchanger 18 consists of a tube of conduit wound around a continuous loop. The loop allows heat transfer to warm or cool the lubricating liquid 37. The heat exchanger 18 is placed in the axle assembly such that the loop is placed under a pool of lubricating liquid 37 in the chamber 36.

  During initial operation of the vehicle, or operation at a relatively low speed, the efficiency of the axle assembly is improved by heating the lubricant 37. The coolant is circulated to the chamber 36 via the inlet conduit 14. Initially, the temperature of the lubricant 37 in the axle assembly is approximately the same as the ambient temperature of the external environment. As the coolant circulates from the engine block 8 to the axle assembly 20, the coolant warms up due to engine operation. When the coolant thus warmed circulates through the heat exchanger 18 of the axle assembly 20, the lubricating liquid 37 is heated.

  As the vehicle is driven at higher speeds on the main road, the axle assembly 20 generates significant heat due to friction. The performance of the lubricating liquid 37 is adversely affected by the frictional heat thus generated. At this time, the coolant is at a lower temperature than the temperature of the lubricating liquid 37. As the coolant circulates through the inlet conduit 14 into the heat exchanger 18 in the axle assembly 20, the lubricating liquid 37 is cooled. The coolant thus heated is returned to the radiator 10 of the engine block 8 via the outlet conduit 16.

  With reference now to FIG. 10, an alternative embodiment of the present invention will be described. The axle assembly 1020 includes an axle housing 1022 and an axle cover 1050. A differential assembly 1038 is disposed within the axle housing 1022. Both the axle cover 1050 and the axle housing 1022 have a channel 1060 formed at the lower end of the cover 1050 and the housing 1022. A flexible exhaust pipe 1070 is fed from the main exhaust pipe 1080 and inserted through the channel 1060. The heated exhaust gas flows from the engine room through the main exhaust pipe 1080. A control valve 1072 is used to control the flow of exhaust gas through the flexible exhaust pipe 1070. During initial vehicle operation or when the temperature of the axle assembly is lower than optimal, the control valve 1072 is opened so that hot exhaust gas can flow through the flexible exhaust pipe 1070. The flexible exhaust pipe reconnects with the main exhaust pipe after passing through the axle housing 1022 and the cover 1050. The amount of exhaust can be controlled by a sensor coupled to the control valve 1072 that detects the operating condition of the axle assembly 1020. When the axle assembly 1020 is heated by the exhaust gas, the control valve 1072 closes and the heated exhaust flows only through the main exhaust pipe 1080. Although not described in detail, the spirit of the present invention is that above operation, the fluid in the axle assembly is splashed onto the flexible exhaust pipe to heat the fluid during operation. It should be understood that it includes a flexible exhaust pipe that passes through the axle assembly.

  Referring now to FIG. 11, the heat generated from the operation of the internal combustion engine 1108 may be used to heat the lubricating fluid in the axle assembly 1120. Heat pipes 1114 and 1116 transfer heat from the engine 1108 to the axle assembly 1120. Since the engine and front axle assembly are independent suspensions, the heat pipes 1114 and 1116 are sufficiently capable to cover the maximum travel distance from the engine 1108 to the axle assembly 1120 at any given time. It should be understood that it must be flexible. The heat generated in engine 1108 is transferred to axle assembly 1120 during initial operation of the vehicle.

  As can be seen in FIG. 12, in yet another embodiment of the present invention, the air indicated by the arrows in the figure is heated as it passes over the engine 1208. The vehicle body has a channel 1213 that is cast to receive an air flow from the engine 1208 and redirect the concentrate toward the axle assembly 1220. Since air is warmed as it passes over the engine 1208, the concentrated output of air at the axle assembly 1220 has a warming effect, thus increasing the temperature of the lubricating fluid within the axle assembly 1220.

  Another application of the present invention involves the use of an electrical heating element 1301 within the axle assembly 1320, as best seen in FIGS. In FIG. 13 a, the electric heating element 1301 is inserted through the carrier 1322 and is located below the surface of the lubricating liquid 1337. In FIG. 13 b, the electrical heating element 1301 is wound around the shaft of the pinion bearing cavity of the carrier 1322. FIG. 13 c shows the insertion of the electrical heating element 1301 through the axle housing cover 1350. Next, the electric heating element 1301 is disposed in the pool of the lubricating liquid 1337. In FIG. 13d, the electrical heating element 1301 is mounted in a passage cast or drilled in the axle carrier 1322. On the other hand, FIG. 13e uses a passage cast in the axle cover 1350 to accommodate the electrical heating element 1301 to preheat the lubricant. In all the above-described embodiments of FIG. 13, the electric heating element is coupled to a vehicle power source. The vehicle generates power.

  While the above invention has been shown and described in accordance with a plurality of preferred embodiments, it will be understood that various changes in form and detail may be made without departing from the spirit and scope of the invention. Let's go. For example, the above-described embodiment uses the coolant from the engine block 8, but exhaust gas from the engine can also be used as a medium in the heat exchange device. In this case, the exhaust gas is conveyed to the heat exchanger via inlet and outlet conduits. The heat source may be regulated by a suitable thermostatic device or logic controller. Alternatively, the walls of the passages cast or made in the vehicle body and in the axle assembly may carry exhaust gases.

It is a top view of the vehicle undercarriage (vehicle under carriage). It is a side view of the chassis of the vehicle shown by FIG. It is sectional drawing of the axle assembly provided with the differential. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly. FIG. 6 is a cross-sectional view of yet another embodiment of an axle assembly. FIG. 6 is a cross-sectional view of an axle assembly. FIG. 6 is a cross-sectional view of an axle assembly housing. It is sectional drawing of an axle assembly cover. FIG. 6 is a cross-sectional view of an axle assembly. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly. It is a side view of an engine block provided with a transfer case and a front differential. It is a side view of an engine block, a transfer case, and a rear differential. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly. FIG. 6 is a cross-sectional view of another embodiment of an axle assembly.

Explanation of symbols

8 engine block 10 engine 12 vehicle 14 fluid conduit 16 fluid conduit 18 heat exchanger 20 axle assembly 22 housing 24 inlet passage 26 outlet passage 30, 32 axle opening 36 chamber 37 lubricant 38 differential assembly 414, 416 conduit 418 heat exchange 422 Housing 437 Lubricating fluid 514 Inlet conduit 516 Outlet conduit 518 Heat exchanger 520 Axle assembly 522 Housing 614 Inlet conduit 616 Outlet conduit 618 Heat exchanger 619 Cooling fin 620 Axle assembly 622 Housing 636 Chamber 637 Lubricating fluid 638 Differential assembly 638 Assembly cover 714 Inlet connection 716 Outlet connection 718 Passage 722 Housing 814 Inlet connection 816 Outlet connection 818 Passage 850 Axle assembly Bree cover 914 Inlet connection 916 Outlet connection 918 Passage 920 Axle assembly 922 Axle assembly housing 950 Axle assembly cover 1020 Axle assembly 1022 Axle housing 1038 Differential assembly 1050 Axle cover 1060 Channel 1070 Exhaust pipe 1072 Control valve 1080 Main exhaust pipe 1108 Internal combustion engine 1114, 1116 Heat pipe 1120 Axle assembly 1208 Engine 1213 Channel 1220 Axle assembly 1301 Electric heating element 1320 Axle assembly 1322 Carrier 1337 Lubricating fluid 1350 Axle housing cover

Claims (15)

An assembly for adjusting the temperature of an automobile axle system,
A housing defining a chamber containing lubricating oil therein and a differential assembly disposed within the chamber, wherein a pair of axles aligned along a common axis of rotation project from the differential assembly; ,
A heat exchanger including a fluid conduit disposed in the chamber and having an inlet and an outlet for fluid connection to a fluid circuit of an internal combustion engine;
The assembly wherein the heat exchanger improves the operating efficiency of the axle system.   The apparatus of claim 1, wherein the heat exchanger is immersed in the lubricant.   The apparatus of claim 1, wherein the heat exchanger includes at least one loop of fluid conduits.   The apparatus of claim 1, wherein the fluid conduit is of a serpentine shape.   The apparatus of claim 1, wherein the heat exchanger is adjacent to the differential assembly and is axially spaced from the differential assembly.   The apparatus of claim 1, wherein the heat exchanger is immersed in the lubricant.   The apparatus of claim 1, wherein the fluid conduit is cast into a vehicle framework.   The apparatus of claim 7, wherein the conduit has at least a pair of channels extending therethrough.   The apparatus of claim 1, wherein the conduit comprises a plurality of conduits.   The apparatus of claim 9, wherein the plurality of conduits pass through an outer surface of the axle assembly over a reservoir formed from the lubricant in the axle assembly.   The apparatus of claim 9, wherein the plurality of conduits includes an inlet conduit and an outlet conduit.   The inlet conduit passes over an outer surface of the axle assembly above a reservoir formed from the lubricant, and the outlet conduit is below the reservoir formed from the lubricant in the axle assembly. 12. The device of claim 11, wherein the device passes through the outer surface of the device.   The apparatus of claim 11, wherein the plurality of conduits pass through an outer surface of the axle assembly under a reservoir formed from the lubricant in the axle assembly.   The apparatus of claim 11, wherein a heating element is disposed in at least one of the plurality of conduits.   The apparatus of claim 14, wherein the heating element is electrical.

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