The present invention relates to a differential, including a differential configured to generate electrical power.
Motor vehicle manufacturers are actively working to develop alternative powertrain systems in an effort to reduce the level of pollutants exhausted into the air by conventional powertrains equipped with internal combustion engines, as well as to address the high cost of fuel. Significant development efforts have been directed to electric vehicles, fuel-cell vehicles, and “hybrid” vehicles. Hybrid vehicles are equipped with an internal combustion engine and an electric motor that can be operated independently or in combination with the internal combustion engine to provide motive power to the vehicle and offer a compromise between traditional internal combustion engine powered vehicles and full electric powered vehicles.
As motor vehicle manufacturers shift design considerations from internal combustion engines or standard gasoline motors to electric motors, the need to address recharging the motor vehicle's electric power supply becomes increasingly critical. It may be desirable to generate electrical power from existing motor vehicle components and/or systems. The ability to generate electrical power from the differential, for example, may allow a motor vehicle to recharge its electrical power supply without requiring a significant increase in the number of parts, components, or systems in a motor vehicle.
A differential comprising a differential case and electrical generator is provided. The electrical generator may comprise a first portion that is supported by the differential case and a second portion that is disposed in the differential case in accordance with an embodiment of the invention. The electrical generator may be responsive to rotation of the differential case for generating electrical power.
A differential comprising a differential case, a differential gear set, and an electrical generator is provided. The differential gear set may be disposed within the differential case. The electrical generator may comprise a first portion that is supported by the differential gear set and a second portion that is disposed in the differential case in accordance with an embodiment of the invention. The electrical generator may be responsive to movement of the differential gear set for generating electrical power.
An axle assembly comprising an axle housing, a differential, and an electrical generator is provided. The differential may comprise a differential case. The electrical generator may include a first portion that comprises the differential case and a second portion that comprises the axle housing in accordance with an embodiment of the invention. The electrical generator may be responsive to rotation of the differential case for generating electrical power.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:
Reference will now be made in detail to embodiments of the present invention, examples of which are described herein and illustrated in the accompanying drawings. While the invention will be described in conjunction with embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as embodied by the appended claims.
Powertrain systems may be used for generating power from a source and transferring such power from the source to a driven mechanism. In a typical configuration, power may generated by an engine, may be converted into torque, and may then be “transmitted” through a transmission to a drive shaft. The use of a drive pinion gear and ring gear may be configured to transfer the torque from the drive shaft to the drive axle, as the drive axle is perpendicular to the drive shaft. The drive pinion gear may receive input drive torque from the vehicle driveline. When the teeth of the drive pinion gear engage the ring gear, the ring gear may be configured to turn perpendicular to the drive shaft. The drive axle may be attached to the ring gear through an axle housing and differential. In particular, the ring gear may be attached to the differential by any means conventional in the art, including, but not limited to a plurality of bolts.
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Differential 14 may comprise a differential case. The differential case may include a first end (e.g., a flange end) and a second opposing end (e.g., a bell end) in accordance with an embodiment of the invention. The differential case may be configured to define a gear chamber and house a gear set and various other components of differential 14. The gear set may comprise a plurality (e.g., two) of side gears and a plurality (e.g., two) of pinion gears. The pinion gears may be rotatably supported on a pinion shaft that may be connected to the differential case by various means conventional in the art. The pinion gears may be in meshing engagement with the side gears. The side gears may each include an annular hub portion that is configured to receive an axle shaft of a motor vehicle.
The differential case of differential 14 may be configured for rotation, and the rotation of the differential case may be used to generate electric power in accordance with an embodiment of the invention. For example, the differential 14 may include an electrical generator 20, 120, 220, 320 (e.g., alternator design) for generating electricity to supply power to one or more electrical components (e.g., a battery or electric motor), rather than the differential itself. Although a battery and electric motor are described in detail, the electrical component may comprise any number of other electrical components as understood by those of ordinary skill in the art. The differential 14 may be configured so that only minimal oil may be introduced into the portion of the differential 14 comprising an electrical generator 20, 120, 220, 320.
The electrical generator 20, 120, 220, 320 may be responsive to rotation of the differential case for generating electrical power. In accordance with an embodiment of the invention, the electrical generator 20 may comprise a first portion 22 that is supported by the differential case of differential 14 and a second portion 24 that is disposed within the differential case of differential 14. The first portion 22 of the electrical generator 20 may be connected (e.g., attached) to the differential case in an embodiment of the invention. The first portion 22 of the electrical generator 20 may be integral with the differential case in an embodiment of the invention. The first portion 22 of the electrical generator 20 may, thus, be driven by the differential case during normal driving activities. The second portion 22 of the electrical generator 20 may be internal to the differential case and may be held stationary relative to the differential case and relative to the axle housing 12.
The first portion 22 of the electrical generator 20 may comprise a magnetic rotor, and the second portion 24 of the electrical generator 20 may comprise a stator in accordance with an embodiment of the invention. For example only, the magnetic rotor may comprise a plurality of permanent magnets that are configured in an annular array in connection with an embodiment of the invention. For another example only, the stator may comprise a plurality of windings of an electrical conductor (e.g., copper) surrounding a fixed iron core. The rotor may be configured to fit within the stator in accordance with an embodiment of the invention. For example and without limitation, when the magnets of the rotor are rotated past the permanent magnets of the stator, electrical current may be induced in the windings. Such induced electrical currents may be used to supply electrical power through one or more wires (not shown) to one or more vehicle components during operation of the motor vehicle employing the inventive differential 14. Although certain examples for the magnetic rotor and stator are described herein, the magnetic rotor and stator of the electrical generator 20 may be formed from any desired components that generate electrical power when rotated or otherwise moved relative to one another. The magnetic rotor and stator may be similar in design and functionality to an automotive alternator.
In an embodiment of the invention, the second portion 24 of the electrical generator 20 may comprise a plurality of stators. For example and without limitation, the second portion 24 of the electrical generator 20 may comprise two stators. A first stator may be disposed at a first end of the differential case (e.g., inside of the differential case) in an embodiment. For example, the first end of the differential case may be proximate axle shaft 16. A second stator may be disposed at a second end of the differential case (e.g., inside of the differential case) opposing the first end of the differential case in an embodiment. For example, the second end of the differential case may be proximate axle shaft 18.
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The first portion 22 of the electrical generator 120, 220 may comprise a magnetic rotor, and the second portion 24 of the electrical generator 120, 220 may comprise a stator in accordance with an embodiment of the invention. The magnetic rotor and stator of the electrical generator 120, 220 may be formed from any desired components that generate electrical power when rotated or otherwise moved relative to one another.
In an embodiment of the invention, the second portion 24 of the electrical generator 120 may comprise a plurality of stators. For example and without limitation, the second portion 24 of the electrical generator 120, 220 may comprise two stators. A first stator may be disposed at a first end or side of the differential case (e.g., inside of the differential case) in an embodiment. A second stator may be disposed at a second end or side of the differential case (e.g., inside of the differential case) opposing the first end or side of the differential case in an embodiment. For example, the first end of the differential case may be proximate axle shaft 18 and the second end of the differential case may be proximate axle shaft 18, as generally illustrated in
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The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and various modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the invention and its practical application, to thereby enable others skilled in the art to utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention has been described in great detail in the foregoing specification, and it is believed that various alterations and modifications of the invention will become apparent to those skilled in the art from a reading and understanding of the specification. It is intended that all such alterations and modifications are included in the invention, insofar as they come within the scope of the appended claims. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.