# US 10,501,111 B2 · Steering system for a steerable vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,111 B2 - Document ID: US10501111B2 - Status: Granted - Kind: B2 - Application number: 15/461,966 - Filed: 2017-03-17 - Published: 2017-09-21 - Granted: 2019-12-10 - Earliest claimed: 2016-03-18 - Assignees: Ford Global Technologies, LLC; Thyssenkrupp Presta AG - Applicants: Ford Global Technologies, LLC; ThyssenKrupp Presta Aktiengesellschaft - Inventors: Frank Peter Engels; Kristof Polmans - Web page: https://patentgrep.com/patent/US10501111B2 ## CPC - B62D 5/003: {Backup systems, e.g. for manual steering (B62D5/30 takes precedence)} - B62D 5/001: {Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup} - B62D 5/0484: {for reaction to failures, e.g. limp home} - B62D 7/148: {provided with safety devices} - 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 A steering system for a steerable vehicle includes at least two steerable wheels, to each of which an electrically operable steering actuator to enable the steering actuator to adjust the steering angle of the particular steerable wheel by application of a steering torque. The at least two steering actuators can be mechanically coupled to each other so that, in the event of a failure or a malfunction of the one steering actuator, the steering torque provided by the other steering actuator can be transferred to the one steering actuator, to enable the steering angle of the steerable wheel assigned to the failed steering actuator to still be changed via the other steering actuator. The at least two steering actuators can be mechanically coupled to each other via a bendable shaft or via a universal joint shaft which includes at least two rigid shafts hingedly connected via a universal joint. ## Claims ### Claim 1 A steering system for a steerable vehicle, comprising: at least two steerable wheels, each of which is connected to an electrically operable steering actuator to enable each electrically operable steering actuator to adjust a steering angle of a steerable wheel by application of a steering torque, wherein the electrical operable steering actuators are mechanically coupled to each other in such a way that, in the event of a failure or a malfunction of a first steering actuator, the steering torque provided by a second steering actuator is transferred to the first steering actuator, to enable the steering angle of the steerable wheel connected to the first steering actuator to be changed via the second steering actuator, wherein the electrically operable steering actuators are mechanically coupled to each other by a mechanical coupling comprising a bendable shaft. ### Claim 2 (depends on 1) The steering system as claimed in claim 1, wherein the bendable shaft has an elasticity of torsion such that a steering angle difference, which occurs during trouble-free operation, between the mechanically coupled steering actuators is compensated for, in the absence of transfer, by the bendable shaft, and a steering angle difference exceeding a usual difference effectuates a transfer of the torque between the mechanically coupled steering actuators. ### Claim 3 (depends on 1) The steering system as claimed in claim 1, wherein at least one coupling is incorporated into the mechanical coupling of the electrically operable steering actuators, which is open during trouble-free operation of the steering system and is closed in the event of a malfunction. ### Claim 4 (depends on 1) The steering system as claimed in claim 1, wherein at least one positive-fit coupling is incorporated into the mechanical coupling of the electrically operable steering actuators, wherein the at least one positive-fit coupling permits a relative motion between its input side and its output side to the extent that a steering angle difference, which occurs during trouble-free operation of the steering system, between the mechanically coupled steering actuators is compensated for, in the absence of transfer, by the at least one positive-fit coupling, and a steering angle difference exceeding a usual difference brings about a positive fit of the at least one positive-fit coupling. ### Claim 5 (depends on 4) The steering system as claimed in claim 4, wherein at least one spring element is situated between form-fitting elements of the at least one positive-fit coupling, which allows for an elastic positive fit of the at least one positive-fit coupling in such a way that, in the event of a positive fit of the coupling having an increasing steering-angle difference between its input side and its output side, a higher torque is transferred between the mechanically coupled steering actuators. ### Claim 6 (depends on 1) The steering system as claimed in claim 1, wherein each steering actuator can be disconnected from or connected to the bendable shaft via a coupling. ### Claim 7 (depends on 1) The steering system as claimed in claim 1, comprising: at least two steerable front wheels of the vehicle: and two steerable rear wheels of the vehicle, to each of which a steering actuator is connected for adjusting the steering angle, wherein all four steering actuators are mechanically coupled to each other via the bendable shaft. ### Claim 8 (depends on 1) The steering system as claimed in claim 1, wherein each steering actuator comprises a centering spring element which brings each steering actuator into a defined starting position in the event of a malfunction. ### Claim 9 (depends on 1) A method for steering a vehicle, comprising: providing a steering system as claimed in claim 1; in the event of a failure or a malfunction of a first steering actuator, transferring the steering torque provided by a second steering actuator to the first steering actuator; and enabling a steering angle of the steerable wheel connected to the first steering actuator to be changed via the second steering actuator. ### Claim 10 (depends on 1) The steering system as claimed in claim 1, wherein the bendable shaft is flexible. ### Claim 11 A steering system for a steerable vehicle, comprising: at least two steerable wheels, each wheel connected to an electrically operable steering actuator to enable each electrically operable steering actuator to adjust a steering angle of a steerable wheel by application of a steering torque, wherein the electrically operable steering actuators are mechanically coupled to each other such that, in the event of a failure or malfunction of a first steering actuator, the steering torque provided by the second steering actuator is transferred to the first steering actuator, to enable a steering angle of the steerable wheel connected to the first steering actuator to be changed via the second steering actuator, wherein the electrically operable steering actuators are mechanically coupled to each other for the transfer of a torque from a first steering actuator to a second steering actuator, said steering actuators having a mechanical coupling, wherein the mechanical coupling has an elasticity of torsion such that a steering angle difference, which occurs during trouble-free operation, between the mechanically coupled steering actuators is compensated for, in the absence of transfer, by the mechanical coupling, and a steering angle difference exceeding a usual difference effectuates a transfer of the torque between the mechanically coupled steering actuators. ### Claim 12 (depends on 11) The steering system as claimed in claim 11, wherein the mechanical coupling comprises a bendable, flexible shaft. ### Claim 13 (depends on 11) The steering system as claimed in claim 11, wherein the mechanical coupling comprises a universal joint shaft having at least two rigid shafts that are hingedly connected to each other by a universal joint.