System for controlling the temperature of a vehicle driveline component utilizing forced air flow

Abstract

A system for controlling the temperature of a vehicle driveline component assembly includes using forced air to cool lubricant within the assembly. As heat builds up during braking applications, for example, a controller determines when additional cooling may be needed. An air source is activated to induce air flow through at least one flow passage supported relative to the housing so that the air flowing through the passage can absorb heat from the lubricant. In one example, the air flow passage is supported within the component housing. In another example, the air flow passage is associated with a heat exchanger supported external to the component housing in a strategic location on the vehicle or the housing, for example. A pump responsible for causing the air flow preferably also causes lubricant flow in a desired manner to facilitate heat dissipation.

Description

BACKGROUND OF THE INVENTION

[0001] This invention generally relates to temperature control for a vehicle driveline component assembly. More particularly, this invention relates to a system utilizing forced air flow to maintain a temperature of a vehicle driveline component closer to a desired range.

[0002] A variety of vehicles are manufactured for a variety of purposes. Examples include passenger vehicles, heavy vehicles such as trucks, and off highway vehicles. Each type of vehicle has particular component requirements to meet the needs of the typical situation in which the vehicle is placed during use. Accordingly, a variety of vehicle components have been developed, each having its own benefits and, in some cases, shortcomings or drawbacks.

[0003] In off-highway type vehicles, for example, oil in the brake and axle assemblies tends to heat up during braking applications. In many cases, especially in the case of liquid cooled wet disc brakes, the generated heat exceeds that which can be dissipated by the axle assembly or brake assembly using normal passive methods.

[0004] The heat build up must be dissipated to maximize component life and oil performance. The fatigue performance of components such as gears decreases with incremental rises in temperature. By maintaining an adequate temperature for such components, the fatigue performance is enhanced. In addition, oil properties tend to degrade at elevated temperatures.

[0005] Vehicle manufacturers and suppliers have been forced to design complex and often undesirably costly cooling systems in an attempt to regulate the temperature within the components resulting from braking applications. Alternative heat dissipation techniques are needed.

[0006] This invention provides a temperature regulation strategy that economically maintains at least a portion of a driveline component, such as an axle or brake assembly, within a desired operating range.

SUMMARY OF THE INVENTION

[0007] In general terms, this invention is a system for controlling the temperature of a vehicle driveline component that includes utilizing forced air flow to absorb heat from within the component to promote heat dissipation.

[0008] A system designed according to this invention includes a driveline component assembly housing that houses at least some of an operative portion of the component assembly. At least one lubricant fluid is maintained within the housing. A source of a selected gas, preferably air, is supported in a strategic location relative to the driveline component assembly. At least one gas flow passage is supported relative to the housing such that the passage allows the gas to absorb heat from at least some of the lubricant as the gas flows through the passage.

[0009] In one example, the gas flow passage is within the driveline component assembly housing. In another example, there are a plurality of such passages within the housing.

[0010] Another example embodiment of this invention includes a heat exchanger supported outside of the housing of the component assembly. The gas flow passage extends at least part way through the heat exchanger. A dual action pump causes flow of the lubricant into the heat exchanger and then back into the component housing. As the lubricant passes through the heat exchanger, the air flow, which preferably is also generated by the same pump that is responsible for the lubricant flow, facilitates dissipating heat from the liquid before it is returned to the component housing.

[0011] The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiments. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 schematically illustrates a system designed according to this invention.

[0013] FIG. 2 is a cross sectional illustration showing a selected portion of one example system designed according to this invention.

[0014] FIG. 3 is a cross sectional illustration schematically illustrating another example arrangement of air flow passages designed according to this invention.

[0015] FIG. 4 illustrates an alternative to the embodiment of FIG. 3.

[0016] FIG. 5 illustrates another alternative arrangement compared to the embodiments of FIGS. 2 through 4.

[0017] FIG. 6 schematically illustrates an alternative system designed according to this invention, including a heat exchanger supported external to the component assembly housing.

[0018] FIG. 7 schematically illustrates another example heat exchanger that is useful within a system designed according to this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1 schematically illustrates a system 20 for controlling the temperature of a vehicle driveline component assembly 24. The illustrated example includes a component assembly 24 having an axle assembly portion 26 and brake assembly portions 28. One particular example includes wet disk brake assemblies 28. Such an arrangement is particularly useful for off-highway vehicles, although this invention is not necessarily so limited. The heat build up that occurs during braking applications in such an off-highway vehicle driveline component assembly renders this invention particularly useful for such situations.

[0020] The system 20 includes an air source 30, which preferably includes a pump. At least one flow passage 32 is supported relative to the component assembly 24 so that air flowing through the passage 32 is able to absorb heat from a lubricant 34 as the air flows through the passageway 32. The example air flow passageway 32 includes an inlet 36 coupled with the air source 30 and outlets 38 that allow the air flow through the passage to be exhausted as schematically illustrated by the arrows 40. In the illustrated example, the exhausted air flow 40 preferably is directed into an area between the exterior portion of the housing 42 surrounding the brake assemblies 28 and a wheel rim (not illustrated). The air flow provided into such an area facilitates further heat dissipation as the region between the housing and the wheel rims is recognized as a dead air space. Increasing air flow in such a region facilitates heat dissipation from the housing in that region. Appropriate fittings at the outlet 38 of the flow passageway 32 prevent dirt or other contaminants from entering or blocking the air flow passageway. Given this description, those skilled in the art will be able to select from among commercially available components or to custom design such components to achieve the desired effect.

[0021] A controller 50 preferably communicates with one or more temperature sensors 52 that provide an indication of a temperature within the component assembly 24. The temperature sensors may be any of a variety of known sensors capable of functioning in an axle or brake assembly environment, for example. The controller 50 preferably is programmed to cause operation of the pump within the air source 30 to cause the air flow 40 to occur whenever the temperature within the component assembly 24 is above a selected temperature. Given this description, those skilled in the art will be able to choose appropriate temperature thresholds to meet the needs of a particular driveline component assembly. In another example, the air flow 40 is continuously provided while the vehicle is being used.

[0022] The controller 50 can be a commercially available microprocessor. In one example the controller 50 is a dedicated microprocessor. In another example, the microprocessor 50 is a portion of an engine controller already present on the vehicle. A variety of controllers on vehicles are known. Those skilled in the art who have the benefit of this description will be able to select from among commercially available components or to custom design circuitry and to suitably program the controller to accomplish the results provided by this invention to meet the needs of their particular situation.

[0023] The air flow passage 32 may be within the component assembly or outside of it, depending on the particular arrangement of components on a given vehicle.

[0024] There are a variety of ways of incorporating the air flow passage 32 within the housing 42 of the component assembly 24. One example is shown in FIG. 2 where a single air flow passage 32 extends within the interior of the housing 42. The air flow passage 32 may extend linearly through the housing 42. In another example, the air flow passage 32 has a generally serpentine pathway. In still another example, the air flow passageway winds at least partially circumferentially through the housing 42.

[0025] Another example is shown in FIG. 3 where a plurality of air flow passages 32 are incorporated within the housing 42. FIG. 4 illustrates an example where the air flow passages 32 are at least partially embedded into a wall of the housing 42. The example of FIG. 5 shows the air flow passages 32 formed within the housing 42.

[0026] Tubing for the air flow passages 32 preferably are made from a portion of the housing 42 or from a suitable material, such as metal, that will be able to withstand the temperatures and other factors within the environment of the housing 42. The air flow passageway (or multiple passageways) 32 preferably is situated within the housing 42 such that it does not require redesign of any of the operative components of the axle assembly 26 or the brake assemblies 28.

[0027] Although air is the preferred gas to flow through the passageway 32, other gases or fluids may be used to achieve a different cooling effect. Air is believed to be an economical selection and provides the advantage of being able to be vented to atmosphere without any environmental considerations. Further, any number of a variety of commercially available air pumps can be incorporated into the system 20 to achieve the desired air flow in an economical manner.

[0028] FIG. 6 schematically illustrates another arrangement designed according to this invention. The example of FIG. 6 does not specifically illustrate the controller 50 or temperature sensors 52 for simplicity. The controller 50 and temperature sensors 52 preferably are incorporated in such a system.

[0029] The example of FIG. 6 includes a modified air source 30′ that includes a dual action pump. One function of the pump is to cause the air flow 40 through the air passageway 32. Another function of the pump is to cause a flow of the lubricant 34 from within the housing 42 into a heat exchanger 60. The air flow 40 through the passageway 32 preferably flows through at least a portion of the heat exchanger 60 so that the air flow operates to cool the lubricant 34 present within the heat exchanger before that lubricant is returned to the housing 42.

[0030] The illustrated heat exchanger includes an interior compartment 62 which is a portion of the air flow passageway 32. At least one outlet 64 allows the air flow to vent out of the interior 62 of the heat exchanger 60.

[0031] As the lubricant 34 is pumped through exterior tubing 68 into the heat exchanger 60, it has a first temperature. After flowing through the tubing within the heat exchanger 60, in part because of the air flow 40 through the interior 62 of the heat exchanger, the lubricant is cooled before it returns to the housing 42 through return tubing 70.

[0032] In one example, a dual purpose air source 30′ including a lubricant pump feature preferably is associated with each wheel end of the driveline component assembly 24. Pumps that operate based upon rotation of vehicle wheels can be incorporated into a system designed according to this invention.

[0033] The heat exchanger 60 preferably is supported external to the housing 42 of the driveline component assembly 24. The number of flow passages for lubricant or air through the heat exchanger 60 may be varied depending upon the needs of a particular situation. The schematic illustration of FIG. 6 is intended to provide one example implementation of such a system designed according to this invention.

[0034] FIG. 7 illustrates another heat exchanger arrangement 60 that includes a plurality of fins 72 associated with the lubricant flow passage through the heat exchanger 60. The fins 72 facilitate heat dissipation from the lubricant within the supply tubing 68 before it is returned to the housing through the return tubing 70. Aluminum is one example material to be used for the fins 72. The fins facilitate greater heat dissipation especially because of the forced air flow 40 through the interior 62 of the heat exchanger 60.

[0035] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims

1. A system for controlling a temperature of a vehicle driveline component assembly, comprising: a component housing that houses at least some of an operative portion of the component assembly; at least one lubricant fluid within the housing; a source of a selected gas; at least one gas flow passage supported relative to the housing such that the passage allows the gas to absorb heat from at least some of the lubricant as the gas flows through the passage.

2. The system of claim 1, wherein the passage is within the housing.

3. The system of claim 1, including a plurality of gas flow passages.

4. The system of claim 1, wherein the selected gas comprises air.

5. The system of claim 1, including a heat exchanger having a portion through which at least some of the lubricant flows and wherein the gas flow passage is supported such that the heat is absorbed from the lubricant that flows through the heat exchanger.

6. The system of claim 5, wherein the heat exchanger includes a lubricant conduit and the gas flow passage at least partially contacts the lubricant conduit.

7. The system of claim 6, wherein the gas flow passage surrounds the lubricant conduit within the heat exchanger.

8. The system of claim 1, wherein the source of the gas includes a pump that causes the selected gas to flow through the gas flow passage in a selected direction.

9. The system of claim 8, wherein the gas flow passage includes an outlet through which the gas is vented to atmosphere.

10. The system of claim 9, wherein the component assembly comprises an axle assembly having a brake assembly portion at each end of the assembly and wherein the passage outlet directs the vented gas toward the brake assembly portions.

11. The system of claim 7, wherein the pump causes the lubricant to flow in a selected direction.

12. The system of claim 11, including a heat exchanger having a portion through which at least some of the lubricant flows responsive to operation of the pump and wherein the gas flow passage is supported such that the heat is absorbed from the lubricant that flows through the heat exchanger.

13. A vehicle axle assembly, comprising: a housing; an axle shaft supported within the housing; a brake device supported near each end of the housing; lubricant within the housing, the lubricant heating up as heat is generated by operation of the brake devices; and an air flow passage supported relative to the housing such that the passage allows the air to absorb heat from at least some of the lubricant as the air flows through the passage.

14. The assembly of claim 13, wherein the passage is within the housing.

15. The assembly of claim 13, including a plurality of the air flow passages.

16. The assembly of claim 13, including a pump that causes the air to flow through the passage in a selected direction.

17. The assembly of claim 16, including a heat exchanger having a portion through which at least some of the lubricant flows responsive to operation of the pump and wherein the air flow passage is supported such that the heat is absorbed from the lubricant that flows through the heat exchanger.

18. The assembly of claim 17, wherein the heat exchanger includes a lubricant conduit and the air flow passage surrounds the lubricant conduit.

19. The assembly of claim 13, wherein the air flow passage includes an outlet through which the air passes after the air has absorbed the heat from the lubricant.

20. The assembly of claim 19, wherein the outlet directs the vented air toward portions of the housing associated with the brake assembly portions.