Planetary gear transmission systems or components – Differential planetary gearing – Bevel gear differential
Reexamination Certificate
2000-08-10
2002-08-13
Marmor, Charles A. (Department: 3681)
Planetary gear transmission systems or components
Differential planetary gearing
Bevel gear differential
Reexamination Certificate
active
06432020
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to a differential locking assembly, which may be manually actuated and which is specifically, but not exclusively, adaptable for use on a four wheel drive, off-road vehicle.
2. Description of the Related Art
A differential assembly, of the type found on motor vehicles, comprises a gear system which is generally structured to transfer power from a drive or propeller shaft to the output or drive axle shafts of the vehicle. The differential assembly typically incorporates a ring gear which is secured to a housing or carrier of the differential and rotatable therewith. Also the ring gear is disposed in intermeshing, driven engagement with the propeller or drive shaft. Torque or rotational force is transferred to the axle shafts and their and associated drive wheels. More particularly, the rotational or driving force is transferred from the drive shaft to the differential housing and eventually to the drive axles, which are splined to respectively disposed and rotationally interconnected side gears. The side gears are mounted within the differential housing and are rotationally interconnected by means of a spider gear assembly. The spider gear assembly typically comprises two spaced apart pinion gears, which are interconnected by a cross pin or like structure and which serve to rotationally interconnect each of the two side gears.
In operation, as the drive or propeller shaft rotates, it serves to rotate the ring gear which in turn rotates the differential housing to which the ring gear is securely attached. The two pinion gears, which define the spider gear assembly, rotationally interact with the two side gears, so as to rotate the output axle shafts and the drive wheels mounted on the outer ends thereof. When the motor vehicle is moving in a straight line direction, the ring gear and differential housing rotate together. In this straight line movement, the pinion gears of the spider gear assembly apply equal force to each of the side gears and their attached output axle shafts, as well as the respective wheels secured thereto. However, when the vehicle travels in a turning direction, the resistance against the rotation of one of the output axle shafts increases as the inner and outer wheels turn at different speeds. This difference in speed encourages the differential pinion gears of the spider gear assembly to rotate and turn the side gear on the axle encountering the increased resistance.
As generally described above, the structure and operation of a somewhat conventional differential serves an important purpose in the operation of a motor vehicle, especially when operating in a conventional, “on-road” environment. As set forth above, the use of the differential serves to transmit the driving torque from the drive shaft through the differential and apply such torque to either wheel substantially equally even though one wheel is rotating at a faster rate than the other, when the vehicle is involved in a turning maneuver. However, it is well recognized that in a number of situations it is highly desirable to lock the drive wheels of a vehicle so that they rotate synchronously. By locking the drive wheels of the vehicle to rotate at a synchronous speed, variations in traction of the drive wheels of the vehicle will not affect the rate of relative rotation between the drive wheels which are associated with the same axle. Therefore, the drive wheels associated with a common axle will rotate in unison even though there is variable traction, which normally causes slippage of one or other of the drive wheels.
It is well known that off-road vehicles, when encountering rough terrain, frequently have one or other of the drive wheels inadvertently disposed above or otherwise out of contact with the ground or surface over which the vehicle is traveling. The absence of a differential locking assembly in such situations would result in the free or non-contact wheel rotating while the opposite wheel, disposed in engaging relation with the surface, is absent rotational torque. Accordingly, there is a well recognized need and important use of differential locking assemblies capable of selectively locking the axle shafts of corresponding drive wheels, such that the wheels rotate synchronously regardless of their relative orientation or the amount of resistance being encountered.
Numerous attempts have been made to establish an efficient, durable, high strength locking assembly which may be applied to a variety of vehicles. Such differential locking assemblies are available for both manual and “automatic” activation. In the latter category of automatic activation assemblies, sensing devices are incorporated within the differential so as to automatically activate an associated locking structure and thereby dispose the associated axle shafts into a synchronous, locked mode. While assumed to be functional for their intended purpose, such “automatic” activation assemblies are not particularly applicable or desirable for use in the four wheel drive, “off-road” vehicles, which are specifically designed and structured to travel over extremely rough terrain. In such an environment, the manual actuation of a differential lock is preferable and generally considered to be both more reliable and durable.
Accordingly, there is a significant need in the field of differential locking assemblies for a high strength, durable and consistently operative locking assembly which is particularly, but not exclusively, adaptable for use in off-road, four wheel drive vehicles. The design and structure of such an improved and preferred differential locking assembly should be such as to be readily adaptable for an “after market” application, such that off-road vehicles, of the type described above, can be easily adapted to include an improved differential locking assembly having all of the attributes which are necessary to endure the rigors of off-road operation.
SUMMARY OF THE INVENTION
The present invention is directed towards a locking assembly for the differential of a motor vehicle and is particularly, but not exclusively, adaptable for use on “off-road”, vehicles of the type which are structured or modified to travel over extremely rough terrain. As a result of the vehicle operating in such a harsh environment, it is not uncommon for one of the drive wheels of an associated axle to be lifted or positioned out of contact with the ground or other surface over which the vehicle is traveling. In such instances, the operation of a conventional differential will deliver rotational torque or driving force to the wheel which is not in contact with the surface. For obvious reasons, such a situation is highly undesirable and will significantly affect the efficient and desired operation of the vehicle.
Accordingly, the present invention is directed towards a locking assembly which is preferably, but not exclusively, manually actuated so as to selectively dispose the locking assembly into a either a locked position or an unlocked position, at the will of the operator. When in the locked position, both drive wheels associated with a common axle will be locked so as to rotate in synchronous relation to one another, thereby overcoming the conventional operation of the differential.
More specifically, the differential locking assembly of the present invention is structured to function with cooperative components of a differential, such as, but not limited to the type produced and made commercially available by the Dana Corporation of Toledo, Ohio. As such, a differential housing or carrier has a ring-gear fixedly secured thereto so as to rotate therewith. Also in substantially conventional fashion, the ring gear is rotationally driven by its interconnection with the drive shaft of the vehicle. Such interconnection also serves to rotate the differential housing. Two side gears are mounted within the differential housing and normally rotate relative thereto. The side gears are secured in driving relation to co-extensive axle shafts of an axle assembly, wh
Arrieta Ruben
Rivera Lazaro
Malloy & Malloy P.A.
Marmor Charles A.
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