VEHICLE STEERING DEVICE

• US 20150360715A1
• Filed: 12/26/2013
• Published: 12/17/2015
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: SHIMIZU, Yasuo, IKEGAYA, Manabu, YONEDA, Atsuhiko, MIYOSHI, Takashi, ONIWA, Yoshihiro
• Granted Patent: US 9,533,703 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 5/003 Backup systems, e.g. for manual steering B62D5/30 takes precedence
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: B62D 5/0484 for reaction to failures, e.g. limp home
• CPC Class Codes: B62D 5/0487 detecting motor faults B62D5/0496 takes precedence
• CPC Class Codes: F16D 2041/0601 with a sliding bearing or spacer
• CPC Class Codes: F16D 27/00 Magnetically- or electrically- actuated clutches; Control or electric circuits therefor clutches with magnetisable particles F16D37/02; with electro-rheological fluids F16D37/008
• CPC Class Codes: F16D 41/06 with intermediate wedging coupling members between an inner and an outer surface F16D41/02, F16D41/24 take precedence
• CPC Class Codes: F16D 41/064 the intermediate members wedging by rolling and having a circular cross-section, e.g. balls F16D41/061 takes precedence
• CPC Class Codes: F16D 41/08 with provision for altering the freewheeling action
• CPC Class Codes: F16D 41/088 the intermediate members being of only one size and wedging by a movement not having an axial component, between inner and outer races, one of which is cylindrical

Abstract

The steering device includes first and second motors for steering which have common electric characteristics; first and second current sensors detecting first and second current values in the first and second motor, respectively; and abnormality diagnosis units. The abnormality diagnosis units make an abnormality diagnosis indicating that the steering device is abnormal when difference between the first and second current values exceeds a predetermined threshold value. When some abnormality occurs in the current detecting units for detecting the magnitudes of a current flowing through the steering motor, an abnormality diagnosis is rapidly made by comparing the difference with the predetermined value.

Claims

1. A vehicle steering device comprising:

a steering device configured to turn a steered wheel in accordance with operation of a steering member, the steering device including first and second motors for steering which are connected to each other through a steering force transmitting mechanism and have electric characteristics which are set commonly each other;

a first current detecting unit configured to directly detect a first current value of a current flowing through the first motor;

a second current detecting unit configured to directly detect a second current value of a current flowing through the second motor; and

an abnormality diagnosis unit configured to make a diagnosis indicating that the steering device is abnormal when a difference between the first and second current values detected by the first and second current detecting units exceeds a predetermined threshold value.

2. The vehicle steering device as claimed in claim 1, further comprising:

a reaction force application device, including a third motor, configured to apply a reaction force in response to operation of the steering member;

a first control unit configured to mainly perform drive control of the first motor;

a second control unit configured to mainly perform drive control of the second motor;

a third control unit configured to mainly perform drive control of the third motor, wherein

the first to third control units include the abnormality diagnosis unit and include functions executing common processes whose at least parts are the same;

wherein

the abnormality diagnosis unit compares three processing results obtained by executing the common processes by the first to third control units, respectively, and wherein;

on the basis of the comparison result, when more than one of the three processing results belong to a predetermined allowable range, the abnormality diagnosis unit makes a diagnosis to indicate that the control units corresponding to the more than one of the processing results are normal and a diagnosis to indicate that the control unit corresponding to the processing result outside the processing results of the more than one of the processing results is abnormal.

3. The vehicle steering device as claimed in claim 2, further comprising;

a connecting device, disposed between the steering device and the reaction force application device and configured to switch a mechanical connection between a first rotation shaft on a side of the steering device and a second ration shaft on a side of a reaction force applying device to either of a disconnection state or a connection state,

wherein the connecting device comprises;

a hollow cylindrical member provided at either one of the first rotation shaft or the second rotation shaft;

a cam member, disposed at the other, different from the one, of the first and second rotation shafts, which can be housed in the hollow cylindrical member;

a plurality of pairs of rollers in a gap between the hollow cylindrical member and the cam member;

a plurality of spring members, which are disposed between plurality of pairs of the rollers, respectively, each of which applies a biasing force to the pair of the rollers in such a direction that the rollers are separated;

a switching claw unit provided insertably and removably to and from gaps between the hollow cylindrical member and the cam member;

a switching device switching the switching claw unit to either of a disconnection state in which the switching claw unit is inserted into the gap or a connecting state in which the switching claw units are removed from the gap;

wherein,

when the switching device of the connecting device switches the switching claw unit from the disconnection state to the connecting state in response to an abnormality diagnosis, a plurality of the spring members are released from a pressure force by the switching claw unit, which causes a plurality of pairs of rollers to engage with the gap between the hollow cylindrical member and the cam member in a cuneiform manner, which mechanically connects the first and second rotation shafts to mechanically connect the steering member and the steered wheel.

4. The vehicle steering device as claimed in claim 3, wherein the first to third control devices switch the switching claw unit from the disconnection state to the connection state by performing control to cut off the power supply to the switching device of the connecting device in response to the abnormality diagnosis by the abnormality diagnosis unit.

5. The vehicle steering device as claimed in claim 2, wherein the first to third control devices perform driving at least one of the first motor, the second motor, and the third motor when the first to third control devices cause the switching claw unit to switch from the disconnection states to the connecting status.

6. The vehicle steering device as claimed in claim 1, wherein

the first to third control devices further include a storage storing association information describing types of appropriate steering function modes, the types being associated with a plurality of abnormal places, respectively, and wherein

the first to third control devices perform control to set one of the appropriate steering function modes associated with the abnormal place regarding the abnormality diagnosis unit among the first steering function mode (active variable gear ratio steering;

active VGS), the second steering function mode (variable gear ratio steering;

VGS), a third steering function mode (electric power steering;

EPS), and a fourth steering function mode (manual steering, with reference to the abnormal place regarding the abnormality diagnosis by the abnormality diagnosis unit and the association information.