Patent Application
20050205329
The present application relates to vehicles. More particularly, the present application relates to a vehicle drive system and an electric drive vehicle employing the vehicle drive system.
There is a need in the industry for both conventional mechanical vehicle drive systems as well as electric drive systems that may be used in many applications, including future defense programs. To the maximum extent possible, those drive systems should use existing proven components such as wheels, hubs, brakes, and wheel sensors. It is further desirable that potentially vulnerable components of the drive system be always remote from the drive wheel within the armorized vehicle hull in order to maximize longevity in a combat environment.
With respect to electric drive systems, there are existing motor-in-wheel-hub technology, such as Magnet Motor GmbH that couples the electric motor directly to one of the individual wheel-hubs. There are certain disadvantages to this type of technology in that non-standard wheels and hubs must be used in order to accommodate the relatively large size of electric motor residing within the wheel-hub. Additionally, placing the electric motor, which is highly vulnerable, in the wheel-hub tends to make the vehicle employing such a drive system more vulnerable in a combat environment.
Some of the characteristics of a vehicle which directly affect the propulsion are:
The advantage of multiple sprocket propulsion for tracked vehicles or individual wheel drive for wheeled vehicles is for improved traction/mobility along with steering capability such as: pivot-steering at zero speed, skid-steering at up to 10 mph, and differential-steering from 10-80 mph on a highway. Additionally, an individually driven wheel provides more options for vehicle recovery in a combat environment. For example, if two of six individually driven wheels are disabled, the remaining four individually driven wheels might readily be used for vehicle recovery.
With respect to the more conventional mechanical drive, the major drive components are disposed internal to the vehicle inside the armored hull structure, where they are best protected. The drive through arm of the present invention significantly reduces the un-sprung mass of the suspension by eliminating springs. Additionally, this type of configuration better supports the modularity concept, as tire/wheel-rim sizes can be conventional. Additionally, there is normal space for conventional braking systems in the wheel-rim, including the necessary wheel speed sensors for improved traction/braking and differential steering.
With respect to the electric drive embodiment of the present invention, the electric motors are disposed inboard within the hull structure of the vehicle. In such disposition, the electric motor, as distinct from a motor-in-wheel-hub type technology, is well protected from mud, water and debris. Further, all electric components such as power cables, oil cooling tubes, motors, and motor controllers are well protected behind armor, since they are within the hull structure.
A further advantage of the drive through suspension arm of the present invention is that the connecting shaft of such arm acts as a torque-shaft, providing resilient coupling between the input drive shaft to the suspension arm and the wheel output drive shaft, thereby eliminating the need for suspension springs.
The present invention is a vehicle suspension system including a drive through suspension arm being operably coupled to a motive source and to a ground engaging device for propelling a vehicle and including an internally disposed drive shaft for transmitting rotational torque from the motive source to the ground engaging device and for acting as a resilient torque coupler device acting to provide a spring effect for the ground engaging device. Further, the vehicle includes a motive source and at least one ground engaging device for propelling the vehicle, the motive source being an electric drive that is remotely disposed from the ground engaging device. A method of forming a vehicle is additionally included in the present invention.
The vehicle of the present invention is generally shown at 10 in
Referring to the embodiment of
The output of the motor 12 is coupled to an output coupling device 14. The output coupling device 14 may transfer rotational motion and power by means of a belt drive, a chain drive, or a gear set. Other power transfer means may also be incorporated in the output coupling device 14.
The output coupling device 14 is coupled to a transmission 16. The transmission 16 may have a gear and clutch arrangement, a torque converter and gear arrangement, or a variable speed drive, or other means of power transmission. The transmission 16 has a rather short output shaft 18. The output shaft 18 may either be a solid shaft or may employ universal joints or the like. The output shaft 18 is coupled to a transfer case 20. The transfer case 20 may include a parking brake 21, including a disc and caliper. The transfer case 20 is coupled by a plurality of axial drive shafts 24 to a plurality of differentials 22. In this embodiment, each differential 22 provides power to two transversely opposed wheels 31. The differentials 22 could as well service the sprockets of a tracked vehicle. Each differential 22 has a pair of opposed transverse drive shafts 26. The drive shafts 26 preferably include CV joint 28 disposed within a boot 30 at both ends of the transverse drive shaft 26.
The vehicle 10 of
Each of the six wheels 31 of the vehicle 10 include a conventional brake caliper 42, a conventional brake disc 44, and are damped by a conventional shock absorber 46.
The vehicles 10, 10a each include a plurality of drive through suspension arms 50. In these embodiments, a drive through suspension arm 50 is associated with any wheel 31. The drive through suspension arm 50 is coupled by a respective transverse drive shaft 26 to a respective differential 22.
The drive through suspension arm (suspension arm) 50 includes a housing 52. The housing 52 is a generally rectangular center section. A shock absorber mount 54 is formed integral with the housing 52 for mounting a respective shock absorber 46. The suspension arm 50 is rigidly coupled to structure of the vehicle 10 (or of vehicle 10a, as described below) by mounting flange 53. See
An input bearing receiver 56 is formed at a first end of the center section of the housing 52 and an output bearing receiver 58 is formed at a second, opposed end of the center section of the housing 52. Each of the receivers 56, 58 is formed having a cylindrical inner margin.
In addition to the receivers 56, 58, drive shaft bearing receivers 60a, 60b are also formed at respective ends of the housing 52. Cover plates 62 cover openings defined in the housing 52 that are opposed to the respective input bearing receiver 56 and output bearing receiver 58.
A splined input shaft coupling 64 is mated to splines on the respective transverse drive shaft 26 that is coupled to the suspension arm 50. The input shaft coupling 64 terminates at an input spiral bevel gear 66 and is rotatably borne in a two row bearing assembly 68a, 68b.
Suspension arm 50 includes four different bearing assemblies as is noted in more detail below. Each of the bearing assemblies is a two row bearing assembly that is designed to meet heavy duty applications where maximum capacity is required in a limited space.
The first two such bearing assemblies are the input bearing assembly 68a and the output bearing assembly 68b, noted above. Each of the bearing assemblies 68a, 68b includes a bearing race 70 for supporting the two rows of bearings. A retainer 72 abuts the outermost bearing row.
A bearing housing 74 having a cylindrical exterior margin is disposed within the respective input bearing receiver 56 and output bearing receiver 58. The bearing housing 74 is bolted to the housing 52 of the drive through suspension arm 50.
An output shaft coupling 76 is coupled to the hub of the wheel 31 by a short splined shaft. The output shaft coupling 76, is affixed to the output spiral bevel gear 78 and is rotatably supported by the two row bearing assembly 68b.
An elongated drive shaft 80 is disposed within the housing 52 of the suspension arm 50. The drive shaft 80 has a pair of opposed splines 82. The spline 82 at the input end of the drive shaft 80 is coupled to a shaft input spiral bevel gear 84. The shaft input spiral bevel gear 84 is rotatably engaged (meshed) with the input spiral bevel gear 66. The input end of the drive shaft 80 is rotatably borne in the third of the two row bearing assemblies. Bearing assembly 68c includes a bearing race 70a, a retainer 72a, and a bearing housing 74a.
The drive shaft 80 includes a shaft output bevel gear 86 that is coupled by splines 82 to the drive shaft 80. The shaft output spiral bevel gear 86 is rotatably coupled to the output spiral bevel gear 78. The output end of the drive shaft 80 is rotatably borne within two row bearing assembly 68d. The two row bearing assembly 68d includes a bearing race 70b, a retainer 72b, and a bearing housing 74b. The spiral bevel gears 84, 86 are pinion gears.
It should be noted that the drive shaft 80 is connected to the input/output bevel gears 84, 86 through respective splines 82 at both ends of the drive shaft 80. Such coupling transmits pure rotational torque. The drive shaft 80 is mounted to permit a limited axial rotation in order to prevent any bending moment through the shaft. This arrangement is known as a “quill shaft.” The design allows the drive shaft 80 not only to transmit rotational torque, but also to act as a resilient torque coupler device dampening up/down motion of the wheel 31. The drive shaft 80 acts as a torque shaft and also as a resilient torsion coupling device to protect the components of suspension arm 50 from sudden shock on the respective wheel 31 due to operation over rough terrain. The suspension arm 50, by functioning as a transmitter of rotational torque and also as a resilient torque coupler device obviates the need for any spring suspension of the respective wheel 31, significantly simplifying the suspension needs and reducing unsprung weight. In cooperation with the shock absorber 46, the suspension arm 50 provides both the springing effect and the dampening effect for the respective wheel 31.
Turning to the electric drive embodiment of
Referring to
The output shaft of the electric motor 15 is directly coupled to the input shaft coupling 64 of the suspension arm 50. In all other respects, the suspension arm 50 where used with an electric motor 15 is identical to the suspension arm 50 described above.
Referring to
In operation, the input torque from the motor 15 or transmission 16 (in the case of conventional drive of the vehicle 10) runs through the suspension arm 50 to drive the individual wheel 31. The suspension arm 50 has independent rotation from the motor 15 around its mounting flange 53. This accommodates relatively small up and down rotation of the suspension arm 50 resulting from terrain condition changes. However, the traction rotation comes from the motor 15/transmission 16 through the drive shaft 80 to constantly provide rotational torque to the wheel 31 through the double gearing of the planetary gear set 90 connected to the drive shaft 80 inside the suspension arm 50.
While a number of presently preferred embodiments of the invention have been illustrated and described, it should be appreciated that the inventive principles can be applied to other embodiments following within the scope of the following claims.
The present application claims the benefit of U.S. Provisional Application No. 60/547,615, filed Feb. 25, 2004 and incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60547615 | Feb 2004 | US |
