Steering-angle-limiting device of steer-by-wire system

Patent metadata

Field	Value
Publication number	US-11364949-B2
Application number	US-201916255565-A
Country	US
Kind code	B2
Filing date	Jan 23, 2019
Priority date	Oct 25, 2018
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

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.

First claim

What is claimed is:

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 plurality of stoppers including a first stopper and a second stopper, and configured to be rotated while being in direct contact with the cam, wherein the cam is disposed between the first stopper and the second stopper and configured to cause the first and second stoppers 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 first and second stoppers operate abnormally by comparing a current rotation position of the first and second stoppers with a target rotation position, wherein the current rotation position is detected by a plurality of contact sensors when contacted with at least one of the first stopper or the second stopper; and
a fail-safe unit configured to move the first and second stoppers to a position apart from the gear teeth of the stopping gear by applying moving force to the first and second stoppers in an axial direction of the first and second stoppers when the controller determines that at least one stopper of the first and second stoppers operates abnormally,
wherein the fail-safe unit comprises:
a first rotating shaft and a second rotating shaft respectively coupled to end portions of the first and second stoppers, the first and second rotating shafts being movable together with the first and second stoppers in an axial direction thereof;
a solenoid valve configured to be brought into contact with or separated from the first and second rotating shafts and to restrict or permit movement of the first and second rotating shafts; and
a first moving spring and a second moving spring configured to respectively provide an elastic force in the axial direction in which the first and second rotating shafts move.

2. The steering-angle-limiting device according to claim 1 , wherein the first and second rotating shafts are respectively inserted at an intermediate portion thereof through the first and second stoppers so as to be rotatable relative to the first and second stoppers,
wherein a flange block is formed at a first end of the first and second rotating shafts, and the flange block has a cross-sectional area greater than a cross-sectional area of the first and second rotating shafts 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.

3. The steering-angle-limiting device according to claim 2 , wherein at least one guide hole is formed in a portion of a housing that faces a second end of the first and second rotating shafts and configured to guide movement of the first and second rotating shafts,
wherein at least one spacer is provided between the guide hole and at least one of the first rotating shaft or the second rotating shaft, and
wherein a support spring is provided in the housing and configured to apply an elastic force to at least one of the first rotating shaft or the second rotating shaft in a direction opposite to a direction in which the first and second moving springs apply the elastic force to the first and second rotating shafts, the support spring configured to have a spring constant lower than a spring constant of the first and second moving springs.

4. The steering-angle-limiting device according to claim 1 , wherein the plurality of contact sensors are configured to sense the current rotation position of the first and second stoppers when at least one of the first stopper or the second stopper is caught in the gear teeth of the stopping gear,
wherein, upon determining that the target rotation position of the first and second stoppers and the current rotation position of the first and second stoppers sensed by the contact sensor are different from each other, the controller determines that the first and second stoppers operate abnormally and controls operation of the solenoid valve.

5. The steering-angle-limiting device according to claim 1 , 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 first and second stoppers operate abnormally and controls operation of the solenoid valve.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Hwang Sang Woo
• Park Young Dae
• Lee Byung Rim
• Kim Min Jun
• Chang Se Hyun
• Cho Hyeon Seok

Classifications

• B62D3/02 Primary

  mechanical · CPC title

• B62D5/005 Primary

  means for generating torque on steering wheel or input member, e.g. feedback · CPC title

• B62D5/0484 Primary

  for reaction to failures, e.g. limp home · CPC title

• F16H25/16

  for interconverting rotary motion and oscillating motion · CPC title

• F16H61/12

  Detecting malfunction or potential malfunction, e.g. fail safe (in control of hydrostatic gearing F16H61/4192) {; Circumventing or fixing failures} · CPC title