# US 9,751,555 B2 · Steering system for vehicle

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- Number: US 9,751,555 B2
- Document ID: US9751555B2
- Status: Granted
- Kind: B2
- Application number: 14/896,934
- Filed: 2014-06-12
- Published: 2016-06-09
- Granted: 2017-09-05
- Earliest claimed: 2013-06-19
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Yoshihide Sekiya
- Web page: https://patentgrep.com/patent/US9751555B2

## CPC

- B62D 5/003: {Backup systems, e.g. for manual steering (B62D5/30 takes precedence)}
- B62D 5/0409: {Electric motor acting on the steering column}
- B62D 5/046: {Controlling the motor}
- 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 includes a steering unit including a first actuator; a turning unit including a second actuator; and a backup mechanism configured to mechanically couple the steering unit and the turning unit, wherein a maximum torque that the first actuator is able to transmit to the second actuator via the backup mechanism is larger than or equal to a maximum torque that the second actuator is able to transmit to the first actuator via the backup mechanism.

## Claims

### Claim 1

A steering system comprising:
a steering unit including a first actuator;
a turning unit including a second actuator; and
a backup mechanism configured to mechanically couple the steering unit and the turning unit, wherein
a maximum torque that the first actuator is able to transmit to the second actuator via the backup mechanism is larger than or equal to a maximum torque that the second actuator is able to transmit to the first actuator via the backup mechanism.

### Claim 2 (depends on 1)

The steering system according to claim 1, further comprising:
a control unit configured to set a generatable maximum torque of the second actuator on a basis of a vehicle state.

### Claim 3 (depends on 2)

The steering system according to claim 2, wherein
the control unit is configured to set, when a vehicle speed is higher that a first predetermined value, the generatable maximum torque of the second actuator such that the maximum torque that the second actuator is able to transmit via the backup mechanism becomes smaller than or equal to the maximum torque that the first actuator is able to transmit via the backup mechanism.

### Claim 4 (depends on 2)

The steering system according to claim 2, wherein
the control unit is configured to set, when a steering angle is smaller than a second predetermined value, the generatable maximum torque of the second actuator such that the maximum torque that the second actuator is able to transmit via the backup mechanism becomes smaller than or equal to the maximum torque that the first actuator is able to transmit via the backup mechanism.