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US 4,050,328 AGranted
Four-wheel drive vehicle with drive transfer gear assembly
AssigneeEaton Corporation
InventorRowland C. Romick
Life of this patent
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AssigneeEaton Corporation
InventorRowland C. Romick
Estimating the term…
A drive transfer gear assembly for a four-wheel drive truck tractor. The tractor includes a front drive steer axle assembly, a rear drive axle assembly containing the drive transfer gear assembly, and a prime mover drivingly connected to the front and rear drive mechanisms by the drive transfer gear assembly. The front axle assembly includes a rigid axle housing having end sections and a drop center section containing a differential gear set with output gears drivingly connected to wheels pivotally journaled at the outboard ends of the rigid axle housing. The rear axle assembly includes a differential gear set with output gears drivingly connected to the rear wheels, and a drive transfer gear assembly positioned forwardly of the differential gear set. The drive transfer gear assembly includes a torque proportioning planetary gear set, an angled tooth clutch for locking the planetary gear set in response to front wheel spinout, a manual clutch for preventing differentiation of the gears in the planetary gear set, and a torque limiting clutch for preventing overtorque to the front wheel drive mechanism.
In a motor vehicle of the type including a prime mover, front and rear drive axles;
A drive transfer gear assembly for a vehicle of the type including front and rear drive axles each defining a differential housing, and a differential gear set disposed in each such housing and drivingly connected to wheels on the outboard ends of the axles;
A drive train assembly for a motor vehicle of the type including an engine disposed in a position forwardly of said vehicle and an engine drive shaft extending generally longitudinally of the vehicle and driven at its forward end from the engine;
A rear axle assembly for a motor vehicle comprising:
A vehicle comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
With axially applied torque limiting friction surfaces: with flat clutching surfaces, e.g. discs
For driving both front and rear wheels, e.g. four wheel drive vehicles: having a transfer gear
With means for changing distribution of torque between front and rear wheels: self-actuated means, e.g. differential locked automatically by…
Gearings having three or more central gears: composed of a number of gear trains, the drive always passing through all the trains, each train…
Term ended 27 Sep 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to four-wheel drive motor vehicles and, particularly, to four-wheel drive motor vehicles employing a drive transfer gear assembly in the drive train which functions to apportion the torque between the front and rear drive axles.
Many drive transfer gear assemblies of the torque proportioning type have been proposed heretofore. However, these prior art units have met with, at best, only limited commercial success because of several disadvantages. Specifically, these prior art units, particularly when equipped with a one-way clutch device to lock up the gear set upon front wheel overspin, fail to anticipate and make satisfactory provision for particularly damaging torque overload conditions that applicant has found to be generated in various special situations. Further, the one-way clutches provided with these prior art units have been of a relatively bulky and relatively expensive design and the durability of these clutches has been found to be marginal in certain duty cycles. Further, these prior art devices, by their inherent design configuration, have created a relatively high center of gravity for the total rear axle assembly and have complicated the job of providing clearance between the front axle drive shaft and various drive train components.
It is a primary object of the present invention to provide a torque proportioning drive transfer gear assembly which overcomes the noted disadvantages of the prior art units.
These and other objects, features and advantages of the invention will be apparent from the drawings and from the detailed description of the preferred embodiment.
In the drawings:
FIG. 1 is a somewhat schematic view of a motor vehicle embodying the torque proportioning drive transfer gear assembly of the invention;
The motor vehicle seen in FIG. 1 is of the truck tractor type and, broadly considered, includes an engine 10, a body 12 of the cab-over-engine type, a clutch 13, a ratio change transmission 14, a rear axle assembly 16 drivingly coupled to transmission 14 by engine drive shaft 18, and a front drive axle assembly 20 drivingly coupled to rear axle assembly 16 by front drive shaft 22.
The various drive components of rear axle assembly 16 are housed in a rigid unitary housing assembly 24. Housing assembly 24, best seen in FIG's. 3 and 4, includes a rigid rear axle housing 26 having a differential banjo housing portion 28 and axle shaft housing portions 30, 32; a differential carrier housing 34 secured to banjo housing portion 28 by a plurality of bolts 36 (FIG. 3); and a drive transfer housing 38 having front and rear housing sections 40, 42 secured together by a plurality of bolts 44. Housing section 42 is secured to differential carrier housing 34 by a plurality of bolts 35. Axle shaft housing portions 30, 32 journal a pair of rear wheel drive shafts 33.
Front axle assembly 20, partially shown in FIG. 1 but best seen in FIG. 4, includes a rigid unitary housing assembly 45 having a drop center section housing 46, a pair of end section housings 48, and a pair of gear reduction housings 50. A pair of wheel assemblies 52 are pivotally secured to the outboard ends of end section housings 48. Center section housing 46 includes a low profile differential housing portion 54, containing a differential gear set (not shown) connected at its input to front drive shaft 22. A pair of suspension spring assemblies 56 are mounted on center section housing 46 to support body 12 on axle assembly 20. Further details of front axle assembly 20, including details of the housing assembly and the various drive components within the housing assembly, are disclosed in copending U.S. Patent Application Ser. No. 293,204 filed Sept. 28, 1972, now U.S. Pat. No. 3,862,667 and assigned to the assignee of this application.