# US 4,393,952 A · Steering gear for a track-laying vehicle

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- Number: US 4,393,952 A
- Document ID: US4393952A
- Status: Granted
- Kind: A
- Application number: 06/242,332
- Filed: 1981-03-12
- Granted: 1983-07-19
- Earliest claimed: 1979-07-12
- Assignees: Bombardier-Rotax Gesellschaft m.b.H.
- Inventors: Joachim Schreiner
- Web page: https://patentgrep.com/patent/US4393952A

## CPC

- B62D 11/18: the additional power supply being supplied hydraulically
- F16H 2047/045: {the fluid gearing comprising a plurality of pumps or motors}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- F16H: GEARING

## Abstract

A tracklaying vehicle has an engine, a drive shaft, and right and left drive wheels. It is steered by an arrangement having right and left planetary-gear transmissions each provided with a sun gear connected to the respective wheel, a ring gear coaxially surrounding the respective sun gear and connected directly to the drive shaft, at least one planet gear meshing with the respective sun and ring gears, and a planet carrier carrying the respective planet gear. The ring gears are joined together and connected to the drive shaft. Respective independently operable right and left hydrostatic drive motors are connected to the planet carriers of the respective transmissions and can be independently operated for adding of their rotation to or subtracting it from that of the respective output.

## Claims

### Claim 1

A steering arrangement for a tracklaying vehicle having a drive shaft and right and left drive wheels, the steering arrangement comprising:
right and left planetary-gear transmissions each having two inputs and an output, the outputs being connected to the respective drive wheels;
means for connecting one input of each transmission to the drive shaft for joint rotation of the one inputs with the drive shaft;
respective independently operable right and left hydrostatic drive motors connected to the other inputs of the respective transmissions; and
hydrostatic pump means for independently powering and operating the drive motors for adding the rotation of the other inputs to that of the respective outputs.

### Claim 2 (depends on 1)

The steering arrangement defined in claim 1 wherein each of the transmissions includes
a sun gear constituting the respective output;
a ring gear coaxially surrounding the respective sun gear and constituting the respective one input, the ring gears being joined together for joint rotation;
at least one planet gear meshing with the respective sun and ring gears; and
a planet carrier carrying the respective planet gear and constituting the respective other input.

### Claim 3 (depends on 1)

The steering arrangement defined in claim 1 wherein the vehicle has an engine, the hydrostatic pump means being driven thereby.

### Claim 4 (depends on 3)

The steering arrangment defined in claim 3 wherein the hydrostatic pump means includes respective right and left pumps and conduits connecting same to the respective motors.

### Claim 5 (depends on 1)

The steering arrangement defined in claim 1, further comprising means for arresting the drive shaft.

### Claim 6

A steering arrangement for a tracklaying vehicle having an engine, a drive shaft, and right and left drive wheels, the steering arrangement comprising:
right and left planetary-gear transmissions each having a sun gear connected to the respective wheel;
a ring gear coaxially surrounding the respective sun gear and connected directly to the drive shaft, the ring gears being joined together for joint rotation;
at least one planet gear meshing with the respective sun and ring gears; and
a planet carrier carrying the respective planet gear;
respective independently operable right and left hydrostatic drive motors connected to the planet carriers of the respective transmissions; and
hydrostatic pump means driven by the engine for independently powering and operating the drive motors for adding the rotation of the other inputs to that of the respective outputs.