STEERING-ANGLE-LIMITING DEVICE OF STEER-BY-WIRE SYSTEM

• US 20200130733A1
• Filed: 01/23/2019
• Published: 04/30/2020
• Est. Priority Date: 10/25/2018
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: HWANG, Sang Woo, PARK, Young Dae, LEE, Byung Rim, KIM, Min Jun, CHANG, Se Hyun, CHO, Hyeon Seok
• Granted Patent: US 11,364,949 B2
• Time in Patent Office: Days
• CPC Class Codes: B62D 5/001 Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup
• CPC Class Codes: B62D 5/005 means for generating torque on steering wheel or input member, e.g. feedback
• CPC Class Codes: B62D 5/0469 End-of-stroke control
• CPC Class Codes: B62D 5/0484 for reaction to failures, e.g. limp home
• CPC Class Codes: F16H 25/16 for interconverting rotary motion and oscillating motion

Abstract

A steering-angle-limiting device of a steer-by-wire system selectively restricts turning of a steering wheel in a forward direction or in a reverse direction and permits turning of the steering wheel in order to inhibit locking of the steering wheel when the steering-angle-limiting device operates abnormally. Rotation of a stopping gear, which is coupled to a steering shaft, is selectively restricted depending on a change in a rotation angle of a cam, whereby the direction in which the steering wheel turns is selectively limited. In addition, when a stopper operates abnormally, the stopper is moved to a position apart from an end of the radius of rotation of the stopping gear, thereby enabling turning of the steering wheel.

Claims

1. A steering-angle-limiting device of a steer-by-wire system, comprising:

a stopping gear configured to rotate together with a steering shaft;

a cam configured to rotate eccentrically by receiving rotational force from an actuator;

a stopper configured to be rotated while being interlocked with the cam, the stopper configured to selectively restrict rotation of the stopping gear in a forward direction and in a reverse direction by being selectively caught in gear teeth of the stopping gear;

a controller configured to determine whether the stopper operates abnormally by comparing a current rotation position of the stopper with a target rotation position; and

a fail-safe unit configured to move the stopper to a position apart from the gear teeth of the stopping gear by applying moving force to the stopper in an axial direction of the stopper when the controller determines that the stopper operates abnormally.

2. The steering-angle-limiting device according to claim 1, wherein the fail-safe unit comprises:

a rotating shaft axially coupled to an end portion of the stopper, the rotating shaft being movable together with the stopper in an axial direction thereof;

a solenoid valve configured to be brought into contact with or separated from the rotating shaft and to restrict or permit movement of the rotating shaft; and

a moving spring configured to provide an elastic force in the axial direction in which the rotating shaft moves.

3. The steering-angle-limiting device according to claim 2, wherein the rotating shaft is inserted at an intermediate portion thereof through the stopper so as to be rotatable relative to the stopper,

wherein a flange block is formed at a first end of the rotating shaft, and the flange block has a cross-sectional area greater than a cross-sectional area of the rotating shaft and includes a locking recess formed in an intermediate portion thereof, and

wherein the solenoid valve comprises a rod configured to be inserted into or separated from the locking recess.

4. The steering-angle-limiting device according to claim 3, wherein a guide hole is formed in a portion of a housing that faces a second end of the rotating shaft and configured to guide movement of the rotating shaft,

wherein a spacer is provided between the guide hole and the rotating shaft, and

wherein a support spring is provided in the housing and configured to apply an elastic force to the rotating shaft in a direction opposite a direction in which the moving spring applies the elastic force to the rotating shaft, the support spring configured to have a spring constant lower than a spring constant of the moving spring.

5. The steering-angle-limiting device according to claim 2, further comprising:

a contact sensor configured to sense a rotation position of the stopper, the stopper coming into contact with the contact sensor when the stopper is caught in the gear teeth of the stopping gear,

wherein, upon determining that the target rotation position of the stopper and the current rotation position of the stopper sensed by the contact sensor are different from each other, the controller determines that the stopper operates abnormally and controls operation of the solenoid valve.

6. The steering-angle-limiting device according to claim 2, further comprising:

an angle sensor configured to detect a rotation angle of the actuator,

wherein, upon determining that a command value applied to operate the actuator and a measured value of the actuator detected by the angle sensor are different from each other, the controller determines that the stopper operates abnormally and controls operation of the solenoid valve.