US20080150350A1 - Self-contained axle module - Google Patents

Abstract

A self-contained axle module for a vehicle having a support structure is provided. The self-contained axle includes a housing removably coupled to the support structure and an output shaft extending from the housing. An electric motor is coupled to the housing and drives the output shaft. Two wheel end assemblies coupled to the output shaft, and an independent suspension assembly is coupled between each wheel end assembly and the housing, so that the independent suspension assemblies and the wheel end assemblies and the electric motor and the housing are removable from the vehicle as a unit by detaching the housing from the support structure.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• The present application claims the benefit of priority under 35 U.S.C. § 120 as a continuation of U.S. patent application Ser. No. 10/952,540 titled “Self-Contained Axle Module” and having a filing date of Sep. 28, 2004, the complete disclosure of which is hereby incorporated by reference.
FIELD
• The present invention relates generally to hybrid electric vehicles, and more particularly to a self-contained axle module for an electric vehicle.
BACKGROUND
• In a conventional electric vehicle, a prime mover such as a diesel engine, is used to drive an electric generator or alternator which supplies electric current to a plurality of electric motors. The electric motors typically are coupled to wheel sets, in line, on the vehicle. The vehicles that utilize this type of hybrid electric motor are typically railroad locomotives.
• The prime mover drives the generator/alternator that typically produces an AC current that is then fully rectified with resulting DC current and voltage being distributed to current converters coupled to the electric motors. Such systems are highly integrated with each of the components typically designed and manufactured to operate with the other components in the overall system. In other words, “off the shelf” components are not readily adaptable for use in the initial design or ongoing maintenance of such vehicles. Further, such vehicles have multiple components associated with the change of AC to DC to AC power. Maintenance of such systems is expensive since specific components must be used.
• In the use of hybrid drives for such electric vehicles, it is often necessary to add support systems such as pressurized lubrication and supplemental cooling for the motors and other components. Typically, these systems are centrally mounted on the vehicle and require the routing of specialized, pressurized, conduits to move the oil and coolant medium to specific points around the vehicle. Such additional equipment in conduit routings typically take up space that could be utilized for other purposes, such as cargo space. Such arrangements also are not cost effective since additional materials, i.e., conduits, pumps, filters, are required.
• Thus there is a need for a self contained axle module for an electric vehicle that includes lubrication pump, filter, heat exchanger integrated into a single module. There is a further need for a self-contained axle module for a hybrid electric vehicle that is easy to replace and repair, particularly in the field. There is also a need for an electric vehicle that includes a self-contained axle module.
SUMMARY
• There is provided a self-contained axle module for a vehicle. The vehicle includes a support structure, a source for electric power, a source of cooling medium, and a vehicle control device. The self-contained axle includes a first side plate removably coupled to the support structure. A second side plate removably coupled to the support structure. A housing coupled to the first and second side plate. An electric motor coupled to the housing and the source for electric power. A motor drive controller unit coupled to the electric motor and to the vehicle control device to communicate signals to the vehicle control device such that one of the speed and torque of the electric motor is controlled based upon the signals. A gear train is mounted in the housing and coupled to the electric motor and an output shaft, wherein, the self-contained axle module can be selectively coupled and decoupled from the support structure. The self-contained axle module can include a first wheel end assembly coupled to the housing in the output shaft and a second wheel end assembly coupled to the housing and the output shaft. Another embodiment of the self-contained axle module includes an oil pump mounted inside the housing and immersed in oil. A further embodiment of a self-contained axle module includes a power take off apparatus mounted on the housing and coupled to the gear train and a tool.
• There is also provided a vehicle comprising a vehicle support structure with a principle power unit supported by the structure. The principle power unit is not a battery. An electric AC power bus including at least two phase conductors is coupled to the principle power unit. A power storage unit is coupled to the AC power bus. A pair of self-contained axle modules are coupled to the vehicle support structure. A vehicle controller is coupled to each self-contained axle module and the AC power bus. A data bus is coupled to each self-contained axle module and vehicle controller. Each self-contained axle module includes a first side plate removably coupled to the support structure. A second side plate removably coupled to the support structure. The housing coupled to the first and second side plates. An electric motor coupled to the housing and the principle power unit. A motor drive controller unit coupled to the electric motor and to the vehicle controller to communicate signals to the vehicle controller such that one of the speed and torque of the electric motor is controlled based upon the signals. A gear train is mounted in the housing and coupled to the electric motor and an output shaft. The first wheel end assembly is coupled to the housing in the output shaft and a second wheel end assembly is coupled to the housing and output shaft. Each self-contained axle module can be selectively coupled and decoupled from the support structure. Another embodiment of the vehicle includes a plurality of suspension assemblies wherein each suspension assembly independently suspends one of the wheel end assemblies relative to the vehicle support structure.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic diagram of an electric vehicle according to an exemplary embodiment.
• FIG. 2 is a partial perspective view of an exemplary embodiment of a vehicle including a self-contained axle module coupled to a vehicle support structure of the vehicle.
• FIG. 3 is a top view of an exemplary embodiment of a self-contained axle module including two wheel end assemblies.
• FIG. 4 is a rear view of the self-contained axle module illustrated inFIG. 3.
• FIG. 5 is a side view of the self-contained axle module illustrated inFIG. 3.
• FIG. 6 is a perspective view of an exemplary embodiment of a housing and electric motor of a self-contained axle module and illustrating an oil pump mounted in the sump of the housing, an oil filter mounted on the housing, a heat exchanger mounted on the housing and the conduit connections between such devices for cooling and heating oil in the axle module.
DETAILED DESCRIPTION
• FIG. 1 is a schematic diagram of anelectric vehicle10 according to an exemplary embodiment. An electric vehicle is a vehicle that uses electricity in some form or another to provide all or part of the propulsion power of the vehicle. This electricity can come from a variety of sources, such as stored energy devices relying on chemical conversions (batteries), stored electrical charge devices (capacitors), stored energy devices relying on mechanical stored energy (e.g. flywheels, pressure accumulators), and energy conversion products. A hybrid electric vehicle is an electric vehicle that uses more than one sources of energy, such as one of the electrical energy storage devices mentioned above and another source, such as an internal combustion engine. By having more than one source of energy some optimizations in the design can allow for more efficient power production, thus one can use power from different sources to come up with a more efficient system for traction. Theelectric vehicle10 can be used to implement electric vehicles in general and/or hybrid electric vehicles in particular. Theelectric vehicle10 can implement a number of different vehicle types, such as a fire-fighting vehicle, military vehicle, snow blower vehicle, refuse handling vehicle, concrete mixing vehicle, etc.
• In the illustrated embodiment, theelectric vehicle10 includes anengine18, agenerator20, anelectric power converter24, anenergy storage device26, a plurality ofelectric motors28, a plurality ofdrive controllers30, avehicle controller34.Electric vehicle10 optionally includes anenergy dissipation unit32. Thegenerator20, thedrive controllers30, and theelectric power converter24 are interconnected by a power bus42, such as an AC or DC power bus.Electric vehicle10 is generally configured to use a combination of theengine18 and thegenerator20 to provide braking capability and to dissipate excess electrical power generated by theelectric motors28 during regenerative braking.
• Theengine18 is preferably an internal combustion engine, such as a diesel engine configured to both provide mechanical power to thegenerator20 and to receive mechanical power from generator such that may function as a mechanical engine brake or air compressor. Thegenerator20 is coupled to theengine18 and may be configured to function as both generator configured to provide AC or DC power, and as a motor configured to receive electrical power and provide mechanical power to theengine18.
• Theelectric power converter24 is coupled to theenergy storage device26 and is configured to convert the electrical power generated by thegenerator20, or by theelectric motors28 during regenerative braking, to the energy mode required by theenergy storage device26. For example, according to an exemplary embodiment, the electric power converter is configured to convert AC power generated by thegenerator20 to DC power and transfer such converted power to thestorage device26. Theelectric power converter24 may also convert the energy stored in theenergy storage device26 back to the energy mode ofgenerator20 to augment and supplement the power generated bygenerator20 over the power bus42. Theenergy storage device26 may be electric capacitors, electrochemical capacitors or “ultracapacitors,” storage batteries, a flywheel, or hydraulic accumulators.
• Theelectric motors28 are appropriately sized electric motors, which may be AC or DC electric motors. Theelectric motors28 are configured to receive electrical power from the power bus42 in order to provide a mechanical energy output to a wheel or axle. Theelectric motors28 are also configured to receive mechanical energy from the wheel or axle during regenerative braking in order to generate electrical power onto the power bus42.
• Thedrive controllers30 are coupled to eachelectric motor28 and are configured to control the operation of eachelectric motor28. More specifically, the drive controllers are configured to allow theelectric motors28 to either receive electrical power from the power bus42 in order to provide a mechanical energy output to a wheel or axle, or to receive mechanical energy from the wheel or axle during regenerative braking in order to generate electrical power onto the power bus42.
• Thevehicle controller34 is coupled to theengine18, thegenerator20, theelectric power converter24, and thedrive controllers30 via adata bus network76. Thevehicle controller34 is generally configured to control the operation of theengine18, thegenerator20, theelectric power converter24, theenergy storage device26, the plurality ofelectric motors28, and the plurality ofdrive controllers30. More specifically, thevehicle controller34 is configured to assist in controlling the distribution of electrical power on the power bus so that the flow of electrical power fromgenerator20 andengine18 may be reversed to provide braking capability, and so that excess electrical power generated by theelectric motors28 during regenerative braking is routed back to thegenerator20 so that it may be dissipated throughengine18.
• The optionalenergy dissipation unit32 is typically a resistive element through which electrical power generated by theelectric motors28 during regenerative braking is dissipated as heat if the electrical power exceeds the capacity of theenergy storage device26. Preferably,electric vehicle10 is configured such that the excess electrical power generated by theelectric motors28 during regenerative braking is sufficiently dissipated throughengine18 andgenerator20.
• In conventional vehicles and particularly in vehicles having a hybrid electric drive, it is often necessary to add support systems such as pressurized lubrication and supplemental cooling systems. Such systems typically are centrally mounted on the vehicle and require the routing of pressurized oil lines throughout the vehicle. The elimination of or limiting the number of such specialized conduit lines being routed through the vehicle, results in additional space for other components and truck parts. A self-containedaxle module50 for thevehicle10, which includes alubrication pump70, theoil filter72, andheat exchanger82 at the axle and integrating such components into a self-contained axle module minimizes the conduit routings mentioned above.
• A self-containedaxle module50 can be mounted or coupled to thevehicle10support structure12 at any convenient position determined by the manufacturer or user of thevehicle10. Also, because of the modular configuration, a self-containedaxle module50 can be easily removed and replaced for maintenance or repairs. The self-containedaxle module50 only has to be coupled to the source for electrical power such as the principal power unit andgenerator18,20 and the electric AC power bus42. It should be understood that other sources of power, as described above, can be coupled to the self-containedaxle module50 to provide the necessary electrical power to operate theelectric motor28, as described below. In addition to coupling electric power to the self-containedaxle module50, a control signal, through adata bus76 network provides the necessary control and feedback signals for operation of the axle. It is also contemplated that supplemental cooling may be required because of the environment or operating conditions of the self-containedaxle module50 and therefore supplemental cooling source can also be coupled to the axle.
• The self-containedaxle module50 includes afirst side plate52 removably coupled to thesupport structure12 of thevehicle10. Thesecond side plate54 is removably coupled to thesupport structure12. Ahousing56 is coupled to the first andsecond side plates52,54. (SeeFIGS. 3-5.) The side plates can be composed of any suitable material, such as steel, and formed by any convenient and conventional method. Theside plates52,54 are removably coupled to thesupport structure12 of thevehicle10 by bolts, however other means of coupling can be utilized as determined by the user. The positioning of theside plates52,54 along thevehicle support structure12 is determined by the intended use and operation of thevehicle10.
• Thehousing56 can be composed of any suitable material, such as iron, steel, or aluminum and can be cast and machined as designed by the manufacturer. Thehousing56 includes a sump portion in the lowest area of thehousing56. Thehousing56 in addition to the components described below also houses a gear train58 which transmits force from theelectric motor28 to theoutput shaft60. The gear train58 may include several types of gears such as planetary gears, sprocket gears, bevel gears or the like with selected gear ratios as determined by the manufacturer and operator of thevehicle10.
• Anelectric motor28 is coupled to thehousing56 and to the source for electric power. As described above, the source for electric power can be the engine/generator18,20, with the power routed through the power bus42. It should also be understood that the source of power can be theenergy storage device26 as routed through thepower converter24 and the power bus42. Control of the power routing is provided through thevehicle controller34 over thedata bus network76.
• A motordrive control unit30 is coupled to theelectric motor28 and to thevehicle control device34 to communicate signals to thevehicle control device34 such that one of the speed and torque of theelectric motor28 is controlled based upon the signals. Themotor drive controller30 working in conjunction with thevehicle control device34 can operate at preset parameters or in response to inputs from an operator typically situated in the cab of thevehicle10. However, it should be understood that control of the vehicle can be established and maintained outside of thevehicle10 with a tethered control unit remotely by use of radio frequency signals, infrared signals, or the like.
• The self-containedaxle module50 can be selectively coupled and decoupled from thesupport structure12 as determined by the operator of thevehicle10. It should also be understood that the self-containedaxle module50 can be mounted as illustrated inFIG. 2 wherein two separate self-containedaxle modules50 are mounted to thevehicle support structure12 in a tandem arrangement. However, one or both of the illustrated self-containedaxle modules50 can be rotated 180° relative to thevehicle support structure12 as such configuration is convenient or appropriate for the intended use of thevehicle10. It should also be understood that one more or one less self-containedaxle module50 can be coupled or decoupled from thevehicle support structure12 as determined by the user or manufacturer of thevehicle10.
• A self-containedaxle module50 may also include a firstwheel end assembly62 coupled to thehousing56 and theoutput shaft60. A secondwheel end assembly64 can be coupled to thehousing56 and theoutput shaft60. Thewheel end assemblies62,64 can include a wheel, a tire, a wheel brake, and a multiple input drive unit brake. Wheel end assembly receives as inputs rotational mechanical energy from theoutput shaft60. The wheel end assemblies may also be coupled to a track, for example, on a bulldozer.
• A self-containedaxle module50 can also include anoil pump70 mounted inside thehousing56. Theoil pump70 and its associated motor is configured to be immersed in oil contained in the sump portion of thehousing56. (SeeFIG. 6.) Anoil filter72 is also mounted on the housing and fluidly coupled to theoil pump70. Theheat exchanger82 can also be mounted on thehousing56 and configured to provide cooling for the interior of thehousing56, with theheat exchanger82 fluidly coupled to theoil filter72 andoil pump70. Theheat exchanger82 may also be coupled to the source of cooling medium36 which may be the oil in the sump portion of thehousing56 or a supplemental cooling source mounted on thesupport structure12 of thevehicle10 with the oil pump submersed in the oil in thehousing56. Theoil pump70 may also be used to preheat the oil and axle components. Preheating of the oil and the axle components reduces the stress on the components particularly in cool or cold environments. By mounting the oil cooling and pumping components directly onto thehousing56 of the self-containedaxle module50, high pressure oil lines routed through the truck are not necessary thereby providing cost reductions and operational efficiency to the system.
• The self-containedaxle module50 may also include askid plate80 coupled to the first andsecond side plates52,54 and configured to protect the underside portion of the housing56 (SeeFIGS. 3-5.).
• The self-containedaxle module50 may also include a power take-off (PTO)apparatus74 mounted on thehousing56 and coupled to the gear train58 and a tool77 (SeeFIGS. 3 and 4.). The PTO can be used to drive the tool77, such as a pump78 to power other equipment associated with thevehicle10. The PTO can be configured to operate at a speed independent ofwheel14 speed of thevehicle10 and dependent on theelectric motor28 speed or the PTO can be configured to operate at a speed related to bothelectric motor28 speed andwheel14 speed. Theelectric motor28 provides power to the PTO through an associated gear train and can be coupled or uncoupled to theoutput shaft60 of the self-containedaxle module50.
• It is also contemplated that thevehicle10 may also include a plurality ofindependent suspension assemblies86 which independently suspends one of the wheel end assemblies relative to the vehicle support structure.
• For purposes of this disclosure, the term “coupled” means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components or the two components and any additional member being attached to one another. Such joining may be permanent in nature or alternatively may be removable or releasable in nature
• The foregoing description of embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to be limited to the precise forms disclosed, and modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to explain the principles of the self-contained axle module and its practical application to enable one skilled in the art to utilize the various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the self-contained axle module be defined by the claims appended hereto and their equivalents.

Claims (20)

1. A self-contained axle module with independent suspension for a vehicle, with the vehicle including a support structure, a source for electrical power, and a source of cooling medium, the self-contained axle module comprising:

a housing configured to be coupled to the support structure;

an output shaft extending from opposite sides of the housing;

an electric motor coupled to the housing and the source for electric power, and operable to rotate the output shaft;

a motor drive controller unit coupled to the electric motor and configured to control at least one of a speed and a torque of the electric motor;

a first wheel end assembly coupled to the output shaft;

a second wheel end assembly coupled to the output shaft;

a first independent suspension assembly coupled to the housing and supporting the first wheel end assembly;

a second independent suspension assembly coupled to the housing and supporting the second wheel end assembly;

wherein, the first and second independent suspension assemblies and the first and second wheel end assemblies and the housing and the electric motor are configured to be removable from the support structure as a unit by removing the housing from the support structure.

2. The self-contained axle module ofclaim 1, wherein the housing comprises a first side plate and a second side plate configured to be removably coupled to the support structure.

3. The self-contained axle module ofclaim 1, wherein the electric motor is mounted on the housing at an angle, relative to the plane of the support structure, other than 90 degrees.

4. The self-contained axle module ofclaim 3, wherein the angle is between 10 degrees and 40 degrees.

5. The self-contained axle module ofclaim 2, including a skid plate coupled to the first and second side plates and configured to protect the underside portion of the housing.

6. The self-contained axle module ofclaim 1, including a heat exchanger mounted on the housing and configured to provide cooling for an interior of the housing, with the heat exchanger configured to be coupled to the source of cooling medium.

7. A vehicle comprising:

a support structure;

an electric power bus;

at least one self-contained axle module coupled to the support structure; and

wherein each self-contained axle module comprises:

a housing removably coupled to the support structure;

a shaft extending from the housing;

an electric motor coupled to the housing and the electric power bus and operable to drive the shaft;

a first wheel end assembly coupled to the shaft;

a second wheel end assembly coupled to the shaft;

a first suspension assembly independently suspending the first wheel end assembly relative to the housing;

a second suspension assembly independently suspending the second wheel end assembly relative to the housing;

wherein the self-contained axle module is removable as a unit by removing the housing from the support structure.

8. The vehicle ofclaim 7, further comprising a vehicle controller coupled to the self-contained axle module and the electric power bus.

9. The vehicle ofclaim 8 further comprising a data bus coupled to the self-contained axle module and the vehicle controller.

10. The vehicle ofclaim 8, further comprising a motor drive controller unit coupled to the electric motor and to the vehicle controller to communicate signals to the vehicle controller so that at least one of a speed and a torque of the electric motor are controlled based upon the signals.

11. The vehicle ofclaim 8, wherein the vehicle controller is configured to control the electric motor to brake the vehicle.

12. The vehicle ofclaim 7, wherein the self-contained axle module is removably attachable to the vehicle support structure at any one of a plurality of locations along the support structure.

13. The vehicle ofclaim 7, wherein the electric motor is configured to regenerate power back to a principal power unit or a power storage unit of the vehicle.

14. A self-contained and interchangeable axle module for use with a vehicle, the vehicle having a support structure, the axle module comprising:

a housing removably attachable to the support structure;

an output shaft extending from the housing;

at least one electric motor coupled to the housing and operable to drive the output shaft;

a wheel end assembly coupled to one end of the output shaft;

an independent suspension assembly coupled to the wheel end assembly and the housing;

wherein the independent suspension assembly and the wheel end assembly and the electric motor and the housing are removable from the vehicle as a unit by detaching the housing from the support structure.

15. The self-contained and interchangeable axle module ofclaim 14, wherein the housing is removably attachable to the support structure at any one of a plurality of locations along the support structure.

16. The self-contained and interchangeable axle module ofclaim 14, wherein the output shaft comprises a first segment extending outwardly from a first side of the housing and coupled to the first wheel end assembly, and a second segment extending outwardly from a second side of the housing and coupled to the second wheel end assembly.

17. The self-contained and interchangeable axle module ofclaim 14, wherein the housing comprises a first side plate and a second side plate configured for attachment to the support structure.

18. The self-contained and interchangeable axle module ofclaim 14, further comprising a power take-off apparatus mounted on the housing.

19. The self-contained and interchangeable axle module ofclaim 14, further comprising a skid plate coupled to the housing.

20. The self-contained and interchangeable axle module ofclaim 14 further comprising another wheel end assembly coupled to another end of the output shaft, and another suspension assembly coupled to the another wheel end assembly and the housing, so that the independent suspension assemblies and the wheel end assemblies and the electric motor and the housing are removable from the vehicle as a unit by detaching the housing from the support structure.

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