Planetary gear transmission systems or components – Differential planetary gearing – Spur gear differential
Reexamination Certificate
2002-09-24
2004-11-02
Bonck, Rodney H. (Department: 3681)
Planetary gear transmission systems or components
Differential planetary gearing
Spur gear differential
C475S336000, C074S42100R, C074S423000, C074S417000
Reexamination Certificate
active
06811511
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a gearwheel pairing and, to its use for a differential transmission.
WO 92/01877 already discloses a gearwheel pairing which is used in a crown-wheel differential. The gearwheel pairing comprises a crown wheel and a spur wheel meshing with the latter. The spur wheel is supported by the casing in the direction outwards from the crown-wheel differential and on a sleeve of the differential bolt in the inward direction so that meshing engagement between the crown wheel and the spur wheel is always ensured.
Furthermore, DE 195 36 800 A1 shows a rear-axle transmission, in which the drive includes a pinion shaft with a spur wheel gear driving the differential casing.
The object of the invention is to provide a gearwheel pairing comprising at least two gearwheels, in particular for a differential, wherein the gearwheel pairing requires a relatively small number of components for ensuring engagement of the teeth of the gears.
SUMMARY OF THE INVENTION
In a gearwheel pairing, one of the gearwheels has, at least at one side thereof, a lid-shaped stop structure for engaging the other gearwheel for retaining the gear wheels in engagement with one another. The arrangement is expediently used in a differential transmission in particular a crown-wheel differential transmission.
One advantage of the invention is that a displacement of the second gearwheel at least in one direction is prevented as a result of a stop structure provided on the second gearwheel. Since the stop structure extends at least between a plurality of teeth, it can be brought into bearing contact with the teeth of the first gearwheel. There is no longer any need for further components in order to support the second gearwheel in this direction.
In a particularly advantageous embodiment of the gearwheel pairing a crown-wheel/spur wheel pairing is provided, with the result that two gearwheels can be arranged at angle of 90° to one another. With the spur wheel being provided with radial teeth, no forces from the first gearwheel are introduced into the stop structure or the second gearwheel. This is advantageous in terms of efficiency and of wear.
If the radial extent of the stop structure corresponds to the tip circle diameter of the teeth, a compact design can be achieved along with the maximum possible support of the second gearwheel with respect to the first gearwheel.
Preferably, there is a second stop structure which extends opposite the axial end of the second gear wheel. In this way, a displacement of the second gearwheel in its two axial directions is prevented by means of the two stop structures in that the respective stop structures bear against the teeth of the first gearwheel in both directions.
With the stop structure firmly connected to, or being part of, the second gear wheel particularly high forces can be transmitted. By virtue of the rotationally fixed connection between the second gearwheel and the stop structure or even by their being integrally formed with one another, a particularly high tooth-root strength is achieved.
Preferably, the first gear wheel is connected to an axle shaft and the second gear wheel is a differential wheel to provide the gearwheel pairing according to the invention for a differential, in particular a crown-wheel differential. In this case, a differential bolt/differential cross may be dispensed with which is a particularly advantageous.
If the differential casing is provided with, or carries, the stop structure, high drive torques can be transmitted through the differential. This is achieved in that the drive torque is not introduced from the casing of the differential into a differential bolt, but into the stop structure, the latter having a disc-shaped design. This disc-shaped design makes it possible to provide a radial mounting in the casing with respect to the geometric axis of the differential wheel. The bearing surface on the casing is large in comparison with a differential bolt, resulting in a correspondingly low surface pressure in spite of high drive torques.
Use in a drive toothing of a differential makes it possible to transmit particularly high drive torques, since the tooth-root strength of the toothing of the gearwheel of the pinion shaft is particularly high.
In an advantageous embodiment, the gearwheel pairing is formed by a crown wheel and a spur wheel. As compared with the conventional hypoid toothings, there are advantages in terms of efficiency and of the bearing load of the pinion shaft.
Further advantages of the invention are obtained if the crown wheel has teeth with inwardly projecting ribs shaped corresponding to the stop structure of the spur wheel.
The invention will be described in greater detail on the basis of the accompanying drawings.
REFERENCES:
patent: 2270567 (1942-01-01), Slider
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patent: 2774253 (1956-12-01), Minard et al.
patent: 2924998 (1960-02-01), Sem et al.
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patent: 3253483 (1966-05-01), McCaw et al.
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patent: 5472385 (1995-12-01), Vu
patent: 5509862 (1996-04-01), Sherman
patent: 6080076 (2000-06-01), Kwoka et al.
patent: 737 296 (1943-06-01), None
patent: 35 30 190 (1987-03-01), None
patent: 195 36 800 (1996-04-01), None
patent: 100 18 329 (2000-11-01), None
patent: WO 92/01877 (1992-02-01), None
Bach Klaus J.
Bonck Rodney H.
Williams Eric M.
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