# US 8,783,407 B2 · Steering system having a hydraulic steering column

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- Number: US 8,783,407 B2
- Document ID: US8783407B2
- Status: Granted
- Kind: B2
- Application number: 13/577,164
- Filed: 2010-11-24
- Published: 2012-12-06
- Granted: 2014-07-22
- Earliest claimed: 2010-02-25
- Assignees: Thyssenkrupp Presta AG
- Applicants: Manfred Rombold
- Inventors: Manfred Rombold
- Web page: https://patentgrep.com/patent/US8783407B2

## CPC

- B62D 3/14: hydraulic
- B62D 5/003: {Backup systems, e.g. for manual steering (B62D5/30 takes precedence)}
- 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)

## Abstract

The invention relates to a steering system for a motor vehicle, comprising a steering wheel, a steering gear shaft and a hydraulic master unit, the steering gear shaft being in mechanical active connection with the master unit via a toothing, and also comprising hydraulic lines and a hydraulic slave unit in a steering gear which, for swivelling steerable wheels is mechanically coupled therewith, an electronic control for controlling an electric servomotor being provided which is actively connected to the steering gear, the active connection between the steering shaft and the hydraulic master unit being a toothing with a variable transmission.

## Claims

### Claim 1

A steering system for a motor vehicle comprising:
a steering wheel.
a steering shaft,
a hydraulic master unit, the steering shaft being in mechanical active connection with the master unit via a toothing,
hydraulic lines, and
a hydraulic slave unit in a steering gear mechanically coupled to swivelling steerable wheels and coupled by the hydraulic lines to the hydraulic master unit,
wherein the active, connection between the steering shaft arid the hydraulic master unit is a toothing with a variable transmission ratio.

### Claim 2 (depends on 1)

The steering system according to claim 1, wherein the hydraulic master unit comprises a piston/cylinder unit with an axially displaceable piston rod, and wherein the toothing is a variable toothing configured as a toothed segment on the piston rod.

### Claim 3 (depends on 1)

The steering system according to claim 1, wherein the hydraulic master unit comprises a piston rod guided out of a working chamber of the hydraulic master unit, and wherein the toothing is arranged in a portion of the piston rod projecting out of the working chamber.

### Claim 4 (depends on 1)

The steering system according to claim 1, further comprising an expansion tank configured to communicate with at least one of the hydraulic lines or with at least one hydraulic working chamber.

### Claim 5 (depends on 1)

The steering system according to claim 1, further comprising an electronic control configured to control an electric servomotor, wherein the electronic control is actively connected to the steering gear.

### Claim 6

A hydraulic master unit of a hydraulic steering system, comprising:
a piston/cylinder unit having a piston rod; and
an input-side steering shaft which is in mechanical active connection with the piston rod via a toothing wherein the toothing has a variable transmission ratio.