Planetary gear transmission systems or components – Differential planetary gearing – Spur gear differential
Reexamination Certificate
2000-02-23
2002-01-29
Marmor, Charles A. (Department: 3681)
Planetary gear transmission systems or components
Differential planetary gearing
Spur gear differential
C475S227000
Reexamination Certificate
active
06342025
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a differential drive having a differential carrier rotating in a housing, two side shaft gears arranged coaxially relative to said differential carrier, and two sets of differential gears which are supported in the differential carrier and rotate therewith and which each engage one of the side shaft gears, and, respectively, the invention relates to a differential drive having two differential carriers rotating in a housing, two side shaft gears arranged coaxially relative to said differential carriers, and two sets of differential gears which are supported in the differential carriers and rotate therewith and each engage one of the side shaft gears.
The most frequent type of differential drive is a bevel gear differential drive which, in particular, is used in the axle drives of motor vehicles. Bevel gears arranged on radial journals simultaneously engage both side shaft gears provided in the form of crown gears. If the differential carrier is stationary, the side shaft gears—if so—rotate in opposite directions relative to one another. Other applications are conceivable wherein it appears to be more advantageous if, with a stationary differential carrier, the side shaft gears are able to rotate in identical directions.
BRIEF SUMMARY OF THE INVENTION
It is the object of the present invention to provide simple differential drives which embody the above-described structure and carry out the above-described function.
In the case of a drive with one differential carrier, these objectives are achieved with side shaft gears that are crown gears and differential gears that form two sets of straight pinions which rotate on radial journals in the differential carrier, with the pinions of the two sets directly engaging one another in pairs so that, when the differential carrier is stationary, the side shaft gears are able to rotate in identical directions.
In the case of a drive with two differential carriers, these objectives are achieved with side shaft gears that are hollow gears and differential gears that form two sets of straight pinions (planetary gears) which rotate on axis-parallel journals in the differential carriers and engage one single central freely rotatable pinion (sun gear).
Each of said solutions provides a differential drive with a large share of simply designed identical parts; in particular, the differential gears are provided in the form of simple straight pinions. In both cases, the substantially symmetric design means that the side shaft gears rotate in identical directions, as desired, when the differential carrier is held in a stationary position. If, in a preferred application, the differential drive is used in a propeller shaft of a motor vehicle with a permanently-driven driving axle and a driving axle that is driven by said propeller shaft when required, there is provided a brake assembly which is effective between the differential carrier and the housing and which is provided in the form of a band brake, for example. Such a controllable brake assembly permits a jerk-free engaging or a partial locking effect between the two side shaft gears and thus between the two driving axles. When the brake assembly is released, the differential carrier can rotate freely, so that no torque can be transmitted to the second driving axle.
REFERENCES:
patent: 1294040 (1919-02-01), Brown
patent: 1654623 (1928-01-01), Weir
patent: 3735647 (1973-05-01), Glaseman
patent: 4674276 (1987-06-01), Kitaguchi
patent: 4905787 (1990-03-01), Morin
patent: 5098356 (1992-03-01), Guidoni et al.
patent: 5195934 (1993-03-01), Ichiki et al.
patent: 5842946 (1998-12-01), Ichiki
patent: 6015361 (2000-01-01), Yamazaki et al.
patent: 461 730 (1928-06-01), None
patent: 3536195 (1987-04-01), None
patent: 4005204 (1990-08-01), None
General Definitions On Gears and Gear Pairs, DIN 868, p. 11 Dec. 1976.
GKN Viscodrive GmbH
Marmor Charles A.
Pang Roger
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