Patent Application
20060000308
The present invention relates to an axle assembly that utilizes a plurality of electric motors, and more particularly to an axle configuration which locates the electric motors in an opposed arrangement to the axle.
There is an increasing demand for the use of hybrid electric driven and hybrid electric assisted vehicles. Hybrid electric vehicles typically utilize electric motor driven axles, which are often of a multi-axle configuration in military and specialty vehicles systems.
The electric motors are typically sized to meet both torque and speed requirements, which may not be the most effective for the operational requirements of such vehicles. Relatively large electric motors are often utilized to meet the torque requirements, which may result in an oversized motor for most operational conditions. Moreover, the relatively large electric motors may be difficult to package in a multi-axle vehicle configuration. Conversely, utilizing a multiple of relatively smaller electric motors may increase complexity and the difficulty of obtaining a proper gear teeth contact pattern.
Accordingly, it is desirable to provide a lightweight and compact electric motor driven axle configuration which allows the usage of a multiple of relatively smaller electric motors without greatly complicating obtainment of a proper gear teeth contact pattern.
The axle assembly according to the present invention includes a first and a second electric motor which drives a gearbox assembly substantially therebetween. The electric motors drive the gearbox assembly, which drives the vehicle wheels through a first and second axle shaft located along a first axis.
The electric motors each include an output shaft which mount a drive gear respectively thereto. Each drive gear is engaged with and drives a single hollow ring gear which drives the axle shafts. The hollow ring gear is positionally fixed within a main housing portion of a housing assembly. Electric motor housing portions are mounted to the main housing portion and each electric motor is mounted to a respective electric motor housing portion.
A proper gear teeth contact pattern between the drive gear and the ring gear is obtained by adjusting the electric motor housing portion relative the main housing portion. A shim plate is located between the electric motor housing portion and the main housing portion to axially adjust the drive gear relative the ring gear. To radially adjust the drive gear relative the ring gear, elongated apertures are located through the electric motor housing portion to permit the electric motor housing portion to be shifted relative the main housing portion.
The present invention therefore provides a lightweight and compact electric motor driven axle configuration, which allows the usage of a multiple of relatively smaller electric motors without greatly complicating obtainment of a proper gear teeth contact pattern.
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 embodiment. The drawings that accompany the detailed description can be briefly described as follows:
A multiple of axle assemblies 20 each includes an axle 22 driven by one or more electric motors 24. Each axle assembly 20 defines an axis of rotation D substantially transverse the longitudinal members 16 to drive one or more wheels 26. The electric motors 24 are driven by a prime mover 28, which is preferably a hybrid electric drive that powers each of the axle assemblies 20 by powering the electric motors 24. It should be understood, however, that other prime movers such as diesel engines, gas turbines among others will also benefit from the present invention.
Referring to
The electric motors 24a, 24b are located along axis E, which is substantially perpendicular to axis D. The axle assembly 20 may alternatively be powered by a single electric motor to provide a relatively lighter duty axle assembly for yet another vehicle configuration without major modification to the axle assembly. It should be understood that various combinations of the axle assemblies described herein may be provided to particularly tailor an axle assembly to a particular vehicle in a modular manner.
Referring to
Each drive gear 36a, 36b is engaged with and drives a single hollow ring gear 40 which drives the first axle shaft 32a. That is, the ring gear is coaxial with axis D and the hollow ring gear 40 is rotationally engaged with the first axle shaft 32a through splines 41 or the like. The first axle shaft 32a drives the second axle shaft 32b through a gearbox 43 such as a differential or the like. The gearbox 43 may additionally include a speed reduction gearbox to provide a relatively lightweight and compact axle assembly, which will benefit from an electric motor of reduced size.
The hollow ring gear 40 is positionally fixed within a main housing portion 42 of the housing assembly 34 and mounted within a bearing 44 for rotation about axis D. That is, the hollow ring gear 40 is generally not adjustable and gear teeth contact pattern adjustment is through adjustment of the drive gear 36a, 36b relative the ring gear 40.
The housing assembly 34 includes an electric motor housing portion 46a, 46b which is mounted to the main housing portion 42 through fasteners 48 such as bolts or the like. Each electric motor 24a, 24b is mounted to a respective electric motor housing portion 46a, 46b. Each electric motor housing portion 46a, 46b includes a generally cylindrical pinion housing portion 50a, 50b which rotationally supports and at least partially surrounds the drive gears 36a, 36b, respectively. Bearings 52a, 52b are mounted within the pinion housing portion 50a, 50b to support the drive gears 36a, 36b. A retainer assembly 54a, 54b such as a nut and washer is threaded onto an end of each drive gear 36a, 36b to provide axial retention of the bearings 52a, 52b and drive gear 36a, 36b along axis E.
Preferably, each pinion housing portion 50a, 50b mounts an end bearing 56a, 56b which retains a pinion shaft portion 58a, 58b which extends from the end of the drive gears 36a, 36b. In other words, each drive gear 36a, 36b is axial trapped but supported for rotation within the cylindrical pinion housing portion 50a, 50b between the retainer assembly 54a, 54b, the bearings 52a, 52b, and the end bearings 56a, 56b. An electric motor housing access plate 58a, 58b is preferably located within the electric motor housing portion 46a, 46b to provide access, assembly, and maintenance to the retainer assembly 54a, 54b and the bearings 52a, 52b.
The gear teeth contact pattern between the drive gear 36a, 36b and the ring gear 40 is obtained by adjusting the electric motor housing portion 46a, 46b relative the main housing portion 42. Preferably, a shim plate 60 is located between the electric motor housing portion 46a, 46b and the main housing portion 42 to axially adjust the drive gear 36a, 36b relative the ring gear 40 along axis E. To radially adjust the drive gear 36a, 36b relative the ring gear 40, elongated apertures 62 are located through the electric motor housing portion 46a, 46b (
Preferably, an access cover (illustrated in phantom at 66) is located through the main housing portion 42 to permit inspection and adjustment of the gear teeth contact pattern during assembly of the electric motor housing portion 46a, 46b and the main housing portion 42.
It should be further understood that various bearing and seal locations are included within the gearbox. One of ordinary skill in the art, with the benefit of this disclosure, will consider the various bearing and seal locations to be an ordinary engineering problem such that intricate details thereof need not be fully discussed herein.
The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
