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Arvin Meritor Technology, LLC

Meritor Heavy Vehicle Systems Limited

Yakov Fleytman

Silvio Masaaki Yamada

A differential includes a carrier and worm gear assembly that cooperate to provide speed differentiation between first and second output shafts as needed. The carrier is coupled to an axle input gear, such as a ring gear for example, or a transmission shaft. The worm gear assembly includes a first enveloping worm gear that drives the first output shaft and a second enveloping worm gear that drives the second output shaft. First and second gears are supported by the carrier and are each in meshing engagement with the first and second enveloping worm gears in a self-locking arrangement. When the first and second enveloping worm gears rotate they are able to turn the first and second gears during normal road conditions, however, the first and second gears cannot drive or turn the first and second enveloping worm gears during a low traction driving condition.

Worm gear differential

Epicyclic gear train is comprised of a first gear coaxial to second gear and a satellite gear in a mesh with first and second gears. Satellite gear is an enveloping worm and is placed on a rotating carrier for supporting said satellite where carrier is coaxial to first and second gears. Axis of enveloping worm and axis of first and second matting gears are parallel, intersection or crossing. Epicyclic gear train could also be comprised of the first gear coaxial to the second gear and two coaxial enveloping worms attached to each other to rotate together in mesh with first and second gears. Enveloping worms are placed on a rotating carrier for supporting said satellites where carrier is coaxial to first and second gears. Axis of enveloping worms and axis of first and second matting gears are parallel or intersected.

Epicyclic gear train

Enveloping worm threads with less than one revolution have on one side concave surface and on another side convex surface. This makes generation of concave and convex enveloping worm surfaces simultaneously and makes modification of surfaces by individual machining of each surface. Proposed method uses cutting edges that have rotation radius according with radius of curvature of machining surface. Another variation simultaneously cuts several threads, where enveloping worm blank has rotation around its own axis of rotation and relative motion to helical cutter around tooling axis. This reduces production cost and makes manufacturing easily.

Method of producing an enveloping worm

A differential and drive axle assembly is provided with a worm/worm gear input. The worm/worm gear input provides for a small differential and drive axle assembly while also reducing the noise and weight of the assembly.

Drive axle assembly with worm gearset and differential

A drive axle assembly for a vehicle receives input torque from an engine via an input shaft. The input shaft drives a worm which in turn drives a worm gear. The worm gear includes teeth which engage and drive an axle shaft which in turn drives a vehicle wheel. The teeth of the worm gear are defined by a tooth profile which has two pressure angles, one on each side of the tooth. The worm includes a thread with a thread profile that also has two pressure angles, one on each side of the thread. One of the pressure angles on the thread of the worm is greater than its other pressure angle and one of the pressure angles on the worm gear teeth is greater than its other pressure angle.

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Lake Orion, MI, United States of America

Yakov Fleytman