Vehicle steering system

Patent metadata

Field	Value
Publication number	US-9227657-B2
Application number	US-201414222891-A
Country	US
Kind code	B2
Filing date	Mar 24, 2014
Priority date	Apr 3, 2013
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

In a vehicle steering system configured to reduce the burden placed on an operator when steered wheels are returned to a neutral position, a knob for operating a steering wheel is turnably attached to the steering wheel. A switch is attached to the knob. A steered system ECU includes a target steered angle setting unit. The target steered angle setting unit changes a target steered angle to a steered angle corresponding to a position closer to the neutral position of the steered wheels when the switch is turned on in a state where the turning amount of the steering wheel from a turning angle of the steering wheel corresponding to the neutral position of the steered wheels is within a prescribed range.

First claim

What is claimed is:

1. A vehicle steering system comprising:
a switch used to return a steered angle of steered wheels to a neutral position;
a steering angle sensor that detects a steering angle of a steering member; and
a motor controller that controls a steered system motor based on the steering angle detected by the steering angle sensor and an output signal from the switch, wherein:
the vehicle steering system is a vehicle steering system in which there is no mechanical connection between the steering member operated for steering and a steering mechanism that changes the steered angle of the steered wheels, and the steering mechanism is driven by the steered system motor,
in a state where a turning amount of the steering member from a turning angle of the steering member corresponding to the neutral position of the steered wheels is within a prescribed range, operation of the switch causes a neutral position return controller of the motor controller to control the steered system motor such that the steered angle of the steered wheels is changed toward a steered angle corresponding to the neutral position of the steered wheels, and
in a state where the turning amount of the steering member is outside the prescribed range, the operation of the switch causes no change in the steered angle of the steered wheels.

2. The vehicle steering system according to claim 1 , further comprising a steered angle detector that detects the steered angle of the steered wheels, wherein
the neutral position return controller includes:
a target steered angle setting unit that sets a target steered angle based on the steering angle detected by the steering angle sensor and the output signal from the switch, and
a unit that controls the steered system motor such that the detected steered angle detected by the steered angle detector is equal to the target steered angle, and

the target steered angle setting unit includes a unit that changes the target steered angle to a steered angle corresponding to a position closer to the neutral position of the steered wheels when the switch is operated in the state where the turning amount of the steering member from the turning angle of the steering member corresponding to the neutral position of the steered wheels is within the prescribed range.

3. The vehicle steering system according to claim 2 , wherein the switch is disposed on the steering member.

4. A forklift comprising the vehicle steering system according to claim 3 .

5. The vehicle steering system according to claim 2 , wherein the switch is an automatic-return push-button switch.

6. A forklift comprising the vehicle steering system according to claim 5 .

7. The vehicle steering system according to claim 2 , wherein the switch is a strain sensor.

8. A forklift comprising the vehicle steering system according to claim 7 .

9. The vehicle steering system according to claim 2 , wherein the switch is an electrostatic sensor.

10. A forklift comprising the vehicle steering system according to claim 9 .

11. The vehicle steering system according to claim 2 , wherein the steering member is a circular turnable steering wheel.

12. The vehicle steering system according to claim 11 , wherein the prescribed range of the turning amount of the steering member is a range from 360 degrees to 720 degrees or a range from −720 degrees to −360 degrees.

13. A forklift comprising the vehicle steering system according to claim 12 .

14. A forklift comprising the vehicle steering system according to claim 11 .

15. A forklift comprising the vehicle steering system according to claim 2 .

16. The vehicle steering system according to claim 2 , wherein the steered angle of the steered wheels is changed independently from operation of the steering member.

17. The vehicle steering system according to claim 2 , wherein the target steered angle setting unit changes the target steered angle in accordance with the change of the steered angle of the steered wheels.

18. The vehicle steering system according to claim 2 , wherein the target steered angle setting unit changes the target steered angle based on the angle of integral multiple of the steering angle of the steering member detected by the steering angle sensor.

19. A forklift comprising the vehicle steering system according to claim 1 .

20. The vehicle steering system according to claim 1 , wherein the steered angle of the steered wheels is changed based on the angle of integral multiple of the steering angle of the steering member detected by the steering angle sensor.

21. The vehicle steering system according to claim 1 , wherein the direction of the change of the steered angle of the steered wheels caused by the operation of the switch changes depending on the direction of rotation from the turning angle of the steering member corresponding to the neutral position to the steering angle of the steering member detected by the steering angle sensor.

Assignees

• Jtekt Corp

Inventors

• Hayama Ryouhei
• Takazato Akihiro

Classifications

• B62D1/043

  with a device allowing single-hand operation of the steering wheel · CPC title

• B62D5/0466 Primary

  for returning the steering wheel to neutral position · CPC title

• B62D1/046

  Adaptations on rotatable parts of the steering wheel for accommodation of switches · CPC title

• B66F9/24

  Electrical devices or systems · CPC title

• B66F9/07568 Primary

  Steering arrangements · CPC title