WO2022124196A1

WO2022124196A1 - Automatic steering device for vehicle

Info

Publication number: WO2022124196A1
Application number: PCT/JP2021/044293
Authority: WO
Inventors: 隆英齋藤; 光司佐藤
Original assignee: Ntn株式会社
Priority date: 2020-12-07
Filing date: 2021-12-02
Publication date: 2022-06-16
Also published as: JP2022090245A

Abstract

Provided is an automatic steering device comprising a control unit (50) that has a manual steering mode in which the direction of wheels (5) is changed on the basis of a driver's operation of rotating a steering wheel (3), and an automatic steering mode in which the direction of the wheels (5) is automatically changed in a state in which the driver does not perform the operation of rotating the steering wheel (3), the control unit (50) during the automatic steering mode performing control for activating a steering motor (6) in accordance with an external condition of the vehicle detected by an external condition sensor (52). A clutch mechanism (7) is provided on a rotation transmission path (4). The control unit (50) performs control for keeping the clutch mechanism (7) in a disconnected state during the automatic steering mode.

Description

Vehicle automation

The present invention relates to an automatic steering device for a vehicle.

As an automatic steering device that automatically steers the wheels of the vehicle according to the external condition of the vehicle, for example, the one described in Patent Document 1 is known. As shown in FIG. 11, the automatic steering device of Patent Document 1 includes a steering rack 61 that is movably supported in the left-right direction of the vehicle, a steering pinion 62 that meshes with the steering rack 61, and a steering wheel that is rotated by a driver. It has a rotation transmission path 64 that transmits rotation between the steering wheel 63 and the steering pinion 62, and a steering motor 66 that inputs a driving force to the rotation transmission path 64 to steer a pair of wheels 65. The left and right ends of the steering rack 61 are connected to the pair of left and right wheels 65 via a tie rod 67 so that the orientation of the pair of left and right wheels 65 changes according to the movement of the steering rack 61.

The steering motor 66 shown in FIG. 11 is controlled by a control unit (not shown). This control unit has a manual steering mode and an automatic steering mode. The manual steering mode is a mode in which the orientation of the pair of wheels 65 is changed based on the rotation operation of the steering wheel 63 by the driver. In this manual steering mode, the control unit of the steering motor 66 controls to operate the steering motor 66 according to the steering torque detected by the steering torque sensor 68.

Here, the steering wheel 63 and the steering pinion 62 are always mechanically connected via the rotation transmission path 64. Therefore, in the manual steering mode, the rotational operation force of the steering wheel 63 by the driver is transmitted to the steering pinion 62 via the rotation transmission path 64, and the rotational operation force by the driver is supplemented by the driving force of the steering motor 66. As a result, comfortable steering is obtained.

On the other hand, the automatic steering mode is a mode in which the direction of the pair of wheels 65 is automatically changed without the driver rotating the steering wheel 63. In this automatic steering mode, the control unit of the steering motor 66 operates the steering motor 66 according to the external condition of the vehicle detected by an external condition sensor (camera, laser radar, GPS device, etc.) (not shown).

Patent Document 2 also shows a similar automatic steering device. In the automatic steering device of Patent Document 2, the steering motor for steering a pair of wheels is attached to the steering rack instead of being attached in the middle of the rotation transmission path between the steering wheel and the steering pinion as in Patent Document 1. Although it differs from Patent Document 1 in that, the configuration other than that is the same as that of Patent Document 1.

Japanese Unexamined Patent Publication No. 2018-122680 Japanese Unexamined Patent Publication No. 2018-177120

By the way, in the conventional automatic steering device shown in FIG. 11, the steering wheel 63 and the steering pinion 62 are always mechanically connected via the rotation transmission path 64.

Therefore, in the automatic steering mode, when the steering motor 66 operates according to the external condition of the vehicle detected by the external condition sensor (camera or the like) and the direction of the pair of wheels 65 automatically changes, the wheels 65 The steering wheel 63 also rotates in conjunction with the direction of.

Therefore, in the automatic steering mode, for example, when an obstacle is detected in front of the vehicle in the traveling direction, the steering motor 66 is operated to largely change the direction of the wheels 65 in order to avoid the obstacle. There is a possibility that the steering wheel 63 will rotate significantly in conjunction with the direction of the wheel 65. At this time, the inventor of the present application has focused on the problem that if the driver unexpectedly touches the steering wheel 63, he / she may be injured.

The problem to be solved by this invention is to provide an automatic steering device having excellent driver safety.

In order to solve the above problems, the present invention provides an automatic steering device having the following configuration.
A steering rack that is movably supported in the left-right direction of the vehicle and whose left and right ends are connected to the pair of wheels so that the orientation of the pair of left and right wheels changes according to the movement.
A steering pinion that meshes with the steering rack,
The steering wheel that the driver rotates and operates,
A rotation transmission path for transmitting rotation between the steering wheel and the steering pinion,
An external condition sensor that detects the external condition of the vehicle and
A steering motor that inputs a driving force to the rotation transmission path or the steering rack to steer the pair of wheels.
A manual steering mode in which the direction of the pair of wheels is changed based on the rotation operation of the steering wheel by the driver, and the direction of the pair of wheels is automatically changed without the driver rotating the steering wheel. An automatic steering device for a vehicle having an automatic steering mode, and in the automatic steering mode, a control unit for controlling the operation of the steering motor according to the external condition of the vehicle detected by the external condition sensor. In
A clutch capable of switching between a connected state in which rotation is transmitted between the steering wheel and the steering pinion and a cutoff state in which rotation transmission is cut off between the steering wheel and the steering pinion in the rotation transmission path. With a mechanism,
The clutch mechanism is arranged at a position that cuts off the transmission of the driving force of the steering motor to the steering wheel when the clutch mechanism is in the disengaged state.
The control unit controls to hold the clutch mechanism in the disengaged state in the automatic steering mode.
An automatic steering device for vehicles characterized by this.

In this way, in the automatic steering mode, the clutch mechanism provided between the steering wheel and the steering pinion is held in the disconnected state, so that even if the steering motor operates, the driving force of the steering motor is the steering wheel. Do not communicate to. That is, in the automatic steering mode, even if the direction of the wheel automatically changes greatly according to the external condition of the vehicle detected by the external condition sensor, the steering wheel rotates greatly in conjunction with the direction of the wheel. You can prevent it from happening. Therefore, in the automatic steering mode, it is possible to prevent the steering wheel from rotating greatly and injuring the driver, which is excellent in the safety of the driver.

A steering torque sensor that detects the steering torque of the steering wheel by the driver is further provided.
The control unit can be configured to control the steering motor to be operated according to the steering torque detected by the steering torque sensor in the manual steering mode.

In this case, the control unit controls to hold the clutch mechanism in the disengaged state while the vehicle is running and to hold the clutch mechanism in the connected state while the vehicle is stopped in the manual steering mode. It is preferable to configure it as follows.

In this way, while the vehicle is running, the clutch mechanism is held in the disconnected state, so that the steering wheel and the steering pinion are mechanically separated from each other, and the direction of the wheels is adjusted only by the driving force of the steering motor. Since it changes, the relationship between the amount of operation of the steering wheel and the amount of change in the direction of the wheel can be adjusted according to the running state of the vehicle and the like, and an excellent steering feel can be realized. On the other hand, while the vehicle is stopped, the clutch mechanism is held in the connected state, so that the steering wheel and the steering pinion are mechanically connected, and the driver can drive the steering wheel and the steering motor. Since the direction of the wheel is changed by the force, it is possible to perform stationary steering (changing the direction of the wheel while the vehicle is stopped) with a large torque. Also, when the wheel orientation changes to the mechanical limit due to stationary steering, the mechanical connection between the steering wheel and the steering pinion prevents the steering wheel from rotating any further, through which , It is possible to inform the driver that the direction of the wheel has changed to the mechanical limit.

It is preferable that the clutch mechanism employs a non-excitation actuated clutch that is in the disengaged state when energized and in the connected state when not energized.

In this way, even if the power supply related to steering is lost due to an unexpected situation, the clutch mechanism will be in the connected state and the steering wheel and steering pinion will be mechanically connected. It is possible to steer the wheels.

As the clutch mechanism,
The inner ring to which the rotation of the steering wheel is input and
An outer ring that is rotatably supported relative to the inner ring,
An engaging element incorporated between the inner circumference of the outer ring and the outer circumference of the inner ring,
An engager cage movably supported between an engagement position in which the engager engages between the outer ring and the inner ring, and an disengagement position in which the engager is disengaged.
A spring that urges the engager cage from the disengagement position toward the engagement position,
Armatures that are supported so that they can move in the axial direction,
An electromagnet that attracts the armature in the axial direction by energizing,
Adopting an engager type clutch having an motion conversion mechanism that converts the axial movement of the armature due to the energization of the electromagnet into an motion of the engager cage moving from the engagement position to the disengagement position. Then, it is preferable.

In this way, the engaging element type clutch has an extremely low idling torque in the disengaged state, so that the driving force of the steering motor is transmitted to the steering wheel when the control unit holds the clutch mechanism in the disengaged state. Can be effectively blocked.

The steering motor can be attached so as to input a driving force to the rotation transmission path. In this case, the clutch mechanism can be arranged between the steering wheel and a position where the driving force of the steering motor in the rotation transmission path is input.

Further, the steering motor can be attached so as to input a driving force to the steering rack. In this case, the clutch mechanism can be arranged at the end of the rotation transmission path on the side of the steering pinion.

In the automatic steering device of the present invention, the clutch mechanism provided between the steering wheel and the steering pinion is held in the disconnected state in the automatic steering mode, so that even if the steering motor operates, the driving force of the steering motor is maintained. Does not transmit to the steering wheel. That is, in the automatic steering mode, even if the direction of the wheel automatically changes greatly according to the external condition of the vehicle detected by the external condition sensor, the steering wheel rotates greatly in conjunction with the direction of the wheel. You can prevent it from happening. Therefore, in the automatic steering mode, it is possible to prevent the steering wheel from rotating greatly and injuring the driver, which is excellent in the safety of the driver.

The figure which shows typically the automatic steering apparatus which concerns on 1st Embodiment of this invention. Enlarged sectional view of the clutch mechanism shown in FIG. Sectional drawing along line III-III of FIG. An enlarged cross-sectional view of the vicinity of a pair of rollers showing a state in which the roller cage shown in FIG. 3 has moved from the disengagement position to the engagement position. Sectional drawing along VV line of FIG. Sectional drawing along the VI-VI line of FIG. Sectional drawing along the line VII-VII of FIG. Sectional drawing along line VIII-VIII of FIG. The relative rotation of the first division cage and the second division cage shown in FIG. 8A causes the ball to roll in a direction away from the deepest portion of each inclined groove in the circumferential direction, and the first division cage and the second division cage Cross-sectional view showing a state in which the axial spacing of the split cage is expanded. The block diagram which shows the control system of the automatic steering apparatus shown in FIG. The figure which shows typically the automatic steering apparatus which concerns on 2nd Embodiment of this invention. The figure which shows the automatic steering apparatus of the conventional example.

FIG. 1 shows an automatic steering device according to a first embodiment of the present invention. This automatic steering device includes a steering rack 1 that is movably supported in the left-right direction of the vehicle, a steering pinion 2 that meshes with the steering rack 1, a steering wheel 3 that the driver rotates, and a steering wheel 3 and a steering pinion 2. It has a rotation transmission path 4 for transmitting rotation between the wheels, a steering motor 6 for steering a pair of wheels 5 by inputting a driving force to the rotation transmission path 4, and a clutch mechanism 7.

The central portion of the steering rack 1 is housed in the rack housing 8 with both left and right ends exposed. The rack housing 8 supports the steering rack 1 so as to be movable in the left-right direction of the vehicle. The left and right ends of the steering rack 1 are connected to the pair of left and right wheels 5 via the tie rods 9 so that the directions of the pair of left and right wheels 5 change according to the movement of the steering rack 1. The steering pinion 2 is rotatably supported by the rack housing 8.

The rotation transmission path 4 has a plurality of

shafts

11a, 11b, 11c, 11d connected via a shaft joint 10. The shaft joint 10 is, for example, a universal joint or a constant velocity joint. In the middle of the rotation transmission path 4, a reaction force motor 12, a clutch mechanism 7, and a steering motor 6 are provided in this order from the side of the steering wheel 3 toward the side of the steering pinion 2.

The reaction force motor 12 is an electric motor that applies a steering reaction force to the steering wheel 3 in a direction opposite to the rotation direction of the steering wheel 3 by the driver's steering. The reaction force motor 12 includes a steering torque sensor 13 (see FIG. 9) that detects the steering torque of the steering wheel 3 by the driver, and a steering angle sensor 14 (see FIG. 9) that detects the steering angle of the steering wheel 3. It is assembled. The steering angle detected by the steering angle sensor 14 is used for feedback control of the steering motor 6 in the manual steering mode.

The clutch mechanism 7 is a clutch that can switch between the connected state and the disconnected state of rotation by switching between energized and de-energized. The clutch mechanism 7 is in a cutoff state in which the transmission of rotation is cut off between the steering wheel 3 and the steering pinion 2 when energized, and is in a connected state in which rotation is transmitted between the steering wheel 3 and the steering pinion 2 when the power is off. Will be. That is, the clutch mechanism 7 is a non-excitation actuated clutch.

The steering motor 6 is an electric motor attached so as to input a driving force to the rotation transmission path 4 via the reduction gear 15. Here, the input position of the driving force by the steering motor 6 to the rotation transmission path 4 is the position between the clutch mechanism 7 and the steering pinion 2. Further, the clutch mechanism 7 is arranged between the steering wheel 3 and the position where the driving force of the steering motor 6 of the rotation transmission path 4 is input. As a result, when the clutch mechanism 7 is in the disengaged state, it is possible to disengage the transmission of the driving force of the steering motor 6 to the steering wheel 3.

As shown in FIG. 2, the clutch mechanism 7 includes a cylindrical case 20 having both ends open, an inner ring 21, an outer ring 22 supported so as to be relatively rotatable with respect to the inner ring 21, and an inner circumference and an inner ring of the outer ring 22. It has a plurality of

rollers

23a, 23b incorporated between the outer periphery of the 21 and a roller cage 24 for holding the

rollers

23a, 23b.

The inner ring 21 is provided with an input shaft 25 integrally connected to the inner ring 21. The input shaft 25 is connected to the steering wheel 3 (see FIG. 1) via the shaft 11a (see FIG. 1), and when the driver rotates the steering wheel 3, the rotation of the steering wheel 3 is the input shaft. It is designed to be input to the inner ring 21 via 25.

The outer ring 22 is provided with an output shaft 26 integrally connected to the outer ring 22. The output shaft 26 is connected to the steering pinion 2 via the shaft 11b (see FIG. 1) so as to rotate integrally with the steering pinion 2 (see FIG. 1), and when the clutch mechanism 7 is in the connected state, the inner ring 21 is connected. The rotation transmitted from the outer ring 22 to the outer ring 22 is output to the steering pinion 2 side via the output shaft 26.

As shown in FIGS. 3 and 4, a plurality of cam surfaces 27 are provided on the outer periphery of the inner ring 21 at equal intervals in the circumferential direction. The cam surface 27 includes a front cam surface 27a and a rear cam surface 27b arranged behind the front cam surface 27a in the normal rotation direction of the inner ring 21. A cylindrical surface 28 facing the cam surface 27 in the radial direction is provided on the inner circumference of the outer ring 22.

A pair of

rollers

23a and 23b facing each other in the circumferential direction with a spring 29 sandwiched between the cam surface 27 and the cylindrical surface 28 are incorporated. Of the pair of

rollers

23a and 23b, the front roller 23a in the normal rotation direction is incorporated between the front cam surface 27a and the cylindrical surface 28, and the rear roller 23b in the normal rotation direction is the rear cam surface 27b and the cylindrical surface 28. It is built in between. The spring 29 presses the

rollers

23a and 23b in a direction that widens the distance between the pair of

rollers

23a and 23b.

The front cam surface 27a is formed so that the radial distance between the front cam surface 27a and the cylindrical surface 28 gradually decreases from the position of the roller 23a toward the front in the normal rotation direction. The rear cam surface 27b is formed so that the radial distance from the cylindrical surface 28 gradually decreases from the position of the roller 23b toward the rear in the normal rotation direction.

As shown in FIGS. 2 to 4, the roller cage 24 includes a first split cage 24A that supports one of the pair of

rollers

23a and 23b facing each other in the circumferential direction with the spring 29 in between. It comprises a second split cage 24B that supports the other roller 23b. The first split cage 24A and the second split cage 24B are supported so as to be relatively rotatable, and the pair of

rollers

23a and 23b are supported so that the distance between the pair of

rollers

23a and 23b changes according to the relative rotation. Is individually supported.

The first split cage 24A has a plurality of pillar portions 30a arranged at intervals in the circumferential direction, and an annular flange portion 31a connecting the ends of these pillar portions 30a. Similarly, the second split cage 24B also has a plurality of pillar portions 30b arranged at intervals in the circumferential direction, and an annular flange portion 31b connecting the ends of the pillar portions 30b to each other.

The pillar portion 30a of the first split cage 24A and the pillar portion 30b of the second split cage 24B sandwich the pair of

rollers

23a and 23b facing each other in the circumferential direction with the spring 29 in between from both sides in the circumferential direction. Is inserted between the inner circumference of the outer ring 22 and the outer circumference of the inner ring 21.

The inner circumference of the flange portion 31a of the first split cage 24A and the inner circumference of the flange portion 31b of the second split cage 24B are rotatably supported by a cylindrical surface 32 provided on the outer periphery of the input shaft 25. ing. As a result, in the first split cage 24A and the second split cage 24B, the

rollers

23a and 23b are engaged between the cylindrical surface 28 and the cam surface 27 by widening the distance between the pair of

rollers

23a and 23b. Disengagement of the

rollers

23a and 23b between the cylindrical surface 28 and the cam surface 27 is released by narrowing the distance between the mating engagement position (see FIG. 4) and the pair of

rollers

23a and 23b. It can be moved to and from the position (see FIG. 3).

Here, the first split cage 24A and the second split cage 24B are in a state of being urged from the disengagement position to the engagement position by the force of the spring 29. That is, the force of the spring 29 shown in FIG. 3 pressing the pair of

rollers

23a and 23b is transmitted to the first split cage 24A and the second split cage 24B via the pair of

rollers

23a and 23b. The first split cage 24A and the second split cage 24B are in a state of being urged from the disengagement position toward the engagement position.

As shown in FIG. 5, a spring holder 33 is fixed to the side surface of the inner ring 21. The spring holder 33 has a stopper piece 34 located between the

pillar portions

30a and 30b facing each other in the circumferential direction with the pair of

rollers

23a and 23b interposed therebetween. In the stopper piece 34, when both

pillar portions

30a and 30b move in a direction in which the distance between the pair of

rollers

23a and 23b is narrowed, the edges on both sides of the stopper piece 34 receive the

pillar portions

30a and 30b. As a result, the spring 29 between the pair of

rollers

23a and 23b is prevented from being excessively compressed and damaged, and the

rollers

23a and 23a with respect to the cam surface 27 when the distance between the pair of

rollers

23a and 23b is narrowed are prevented. It is possible to keep the position of 23b constant.

As shown in FIG. 6, the spring holder 33 has a spring holding piece 35 for holding the spring 29. The spring holding piece 35 is integrally formed with the stopper piece 34 so as to extend axially between the inner circumference of the outer ring 22 and the outer circumference of the inner ring 21.

As shown in FIG. 2, between the inner circumference of the case 20 and the outer circumference of the input shaft 25, an armature 36 movably supported in the axial direction and an electromagnet 37 that attracts the armature 36 axially by energization are provided. , The rotor 38 arranged between the electromagnet 37 and the armature 36, and the axial movement of the armature 36 due to the energization of the electromagnet 37, the first split cage 24A and the second split cage 24B are engaged with each other. It incorporates an motion conversion mechanism 39 that converts the motion from (see FIG. 4) to the disengagement position (see FIG. 3).

The armature 36 has an annular disk portion 40 and a cylindrical portion 41 integrally formed so as to extend axially from the outer periphery of the disk portion 40. A cylindrical portion 42 integrally formed so as to extend in the axial direction from the outer periphery of the flange portion 31b of the second split cage 24B is press-fitted into the cylindrical portion 41 of the armature 36, and the armature 36 is pressed into the armature 36. It is connected to the second split cage 24B so as to move integrally with the split cage 24B of the second in the axial direction. The rotor 38 is fixed to the outer periphery of the input shaft 25. The rotor 38 and the armature 36 are made of a magnetic material (iron, silicon steel, etc.).

The electromagnet 37 has a field core 43 made of a magnetic material formed in an annular shape, and a solenoid coil 44 wound around the field core 43. The electromagnet 37 forms a magnetic path through the field core 43, the rotor 38, and the armature 36 by energizing the solenoid coil 44, and attracts the armature 36 to the rotor 38.

As shown in FIGS. 7A, 8A, and 8B, the motion conversion mechanism 39 is provided with an inclination of the flange portion 31a of the first split cage 24A on the facing surface of the second split cage 24B with respect to the flange portion 31b. Incorporated between the groove 45a and the inclined groove 45b provided on the facing surface of the flange portion 31b of the second split cage 24B with respect to the flange portion 31a of the first split cage 24A, and between the inclined groove 45a and the inclined groove 45b. It consists of a ball 46. The inclined groove 45a and the inclined groove 45b are formed so as to extend in the circumferential direction, respectively. Further, the inclined groove 45a has a shape having a groove bottom inclined so as to gradually become shallower in one direction in the circumferential direction from the deepest portion 47a having the deepest axial depth, and the inclined groove 45b is also in the axial direction. The shape has a groove bottom inclined so as to gradually become shallower in the other direction in the circumferential direction from the deepest portion 47b having the deepest depth.

In this operation conversion mechanism 39, when the flange portion 31b of the second split cage 24B moves axially toward the flange portion 31a of the first split cage 24A, the balls 46 move in the inclined grooves 45a, respectively. By rolling toward the deepest portions 47a and 47b of 45b, the first split cage 24A and the second split cage 24B rotate relative to each other, and as a result, the pillars 30a and the second of the first split cage 24A are rotated. The pillar portion 30b of the split cage 24B of 2 operates so as to move in a direction in which the distance between the pair of

rollers

23a and 23b is narrowed.

The armature 36 is urged away from the rotor 38 by the force of the spring 29. That is, the force by which the spring 29 shown in FIG. 3 presses the

rollers

23a and 23b in the direction of widening the distance between the pair of

rollers

23a and 23b is transmitted to the first split cage 24A and the second split cage 24B. .. The circumferential force received by the first split cage 24A and the second split cage 24B is axially distant from the rotor 38 by the motion conversion mechanism 39 shown in FIGS. 7 and 8A and 8B. It is converted into force and transmitted to the second split cage 24B. Here, as shown in FIG. 2, since the armature 36 is fixed to the second split cage 24B, the armature 36 is eventually rotated by the force transmitted from the spring 29 via the motion conversion mechanism 39. It is in a state of being urged away from 38.

As shown in FIG. 2, the clutch mechanism 7 is in a cutoff state (idling state) in which the transmission of rotation between the input shaft 25 and the output shaft 26 is cut off when the electromagnet 37 is energized. That is, when the electromagnet 37 is energized, the armature 36 is attracted to the rotor 38, and in conjunction with the operation of the armature 36, the flange portion 31b of the second split cage 24B becomes the flange portion 31a of the first split cage 24A. Moves in the axial direction toward. At this time, the ball 46 of the motion conversion mechanism 39 rolls toward the deepest portions 47a and 47b of the

inclined grooves

45a and 45b, so that the first split cage 24A and the second split cage 24B rotate relative to each other. .. Then, due to the relative rotation of the first split cage 24A and the second split cage 24B, the pillar portion 30a of the first split cage 24A and the pillar portion 30b of the second split cage 24B are paired. The

rollers

23a and 23b are pressed in the direction in which the distance between the

rollers

23a and 23b is narrowed, and as a result, the front roller 23a in the normal rotation direction is in an engagement standby state (the front roller 23a and the cylindrical surface 28 in the normal rotation direction). Although there is a small gap between them, when the input shaft 25 rotates in the reverse direction, the roller 23a immediately engages between the cylindrical surface 28 and the front cam surface 27a), and the rear side in the normal rotation direction is released. The roller 23b is in an engagement standby state (there is a small gap between the roller 23b on the rear side in the normal rotation direction and the cylindrical surface 28, but when the input shaft 25 rotates in the normal rotation direction, the roller 23b immediately moves to the cylindrical surface 28 and the rear cam. The state of being engaged between the surfaces 27b) is also released. In this state, even if rotation is input to the input shaft 25, the rotation is not transmitted from the input shaft 25 to the outer ring 22, and the input shaft 25 idles.

On the other hand, when the energization of the electromagnet 37 is stopped, the clutch mechanism 7 is in a connected state in which rotation is transmitted between the input shaft 25 and the output shaft 26. That is, when the energization of the electromagnet 37 is stopped, the armature 36 moves axially in the direction away from the rotor 38 by the force of the spring 29. At this time, due to the force of the spring 29 that presses the

rollers

23a and 23b in the direction in which the distance between the pair of

rollers

23a and 23b is widened, the roller 23a on the front side in the normal rotation direction has the cylindrical surface 28 on the inner circumference of the outer ring 22. And the roller 23b on the rear side in the normal rotation direction, which is engaged between the front cam surface 27a on the outer periphery of the inner ring 21, the cylindrical surface 28 on the inner circumference of the outer ring 22 and the rear cam surface 27b on the outer periphery of the inner ring 21. It will be in a state of being engaged with. When the input shaft 25 rotates in the normal rotation direction in this state, the rotation is transmitted from the input shaft 25 to the outer ring 22 via the roller 23b on the rear side in the normal rotation direction. Further, when the input shaft 25 rotates in the reverse direction, the rotation is transmitted from the input shaft 25 to the outer ring 22 via the roller 23a on the front side in the forward rotation direction.

The reaction force motor 12, the clutch mechanism 7, and the steering motor 6 shown in FIG. 1 are controlled by the control unit 50 shown in FIG. On the input side of the control unit 50, a steering torque sensor 13 that detects the steering torque of the steering wheel 3 (see FIG. 1) by the driver, a steering angle sensor 14 that detects the steering angle of the steering wheel 3, and a vehicle. The vehicle speed sensor 51 that detects the traveling speed and the external condition sensor 52 that detects the external condition of the vehicle are electrically connected. The external status sensor 52 is a camera, a laser radar, a GPS device, or the like mounted on the vehicle. A steering motor 6, a clutch mechanism 7, and a reaction force motor 12 are electrically connected to the output side of the control unit 50.

The control unit 50 has a manual steering mode and an automatic steering mode as control modes. The manual steering mode is a mode in which the orientation of the pair of wheels 5 is changed based on the rotation operation of the steering wheels 3 by the driver. The automatic steering mode is a mode in which the direction of the pair of wheels 5 is automatically changed without the driver rotating the steering wheel 3. Switching between the manual steering mode and the automatic steering mode is performed by the driver operating a switch provided in the vehicle or the like.

In the automatic steering mode, the control unit 50 operates the steering motor 6 according to the external condition of the vehicle detected by the external condition sensor 52 (camera or the like), and the direction of the pair of wheels 5 is determined by the driving force of the steering motor 6. Is controlled to change. In parallel with this, the control unit 50 controls to keep the clutch mechanism 7 in the disengaged state by energizing the clutch mechanism 7.

In this automatic steering mode, the clutch mechanism 7 shown in FIG. 1 is held in the disengaged state, so that even if the steering motor 6 operates and the orientation of the pair of wheels 5 automatically changes, the steering motor 6 of the steering motor 6 operates. The rotation due to the driving force is cut off by the clutch mechanism 7 and is not transmitted to the steering wheel 3. At this time, the steering wheel 3 may be kept stopped without operating the reaction force motor 12, or the reaction force motor 12 is operated in response to the operation of the steering motor 6, and the steering wheel 3 becomes smaller. It may be rotated.

When the reaction force motor 12 is operated in response to the operation of the steering motor 6, it is assumed that the clutch mechanism 7 is in the engaged state in the same direction as the rotation direction of the steering wheel 3 when the clutch mechanism 7 is in the engaged state. The reaction force motor 12 can be controlled so that the steering wheel 3 rotates at a rotation angle of half (preferably 1/5 or less) of the rotation angle of the steering wheel 3 at that time. In the automatic steering mode, the driver can arbitrarily select either the steering non-rotation mode in which the reaction force motor 12 is not operated or the steering rotation mode in which the reaction force motor 12 is operated by a switch or the like. It may be configured.

On the other hand, in the manual steering mode, the control unit 50 determines whether the vehicle is running or stopped based on the running speed of the vehicle detected by the vehicle speed sensor 51. When it is determined that the vehicle is running, the clutch mechanism 7 is held in the disengaged state, and in that state, the steering motor 6 is controlled to be operated according to the steering torque detected by the steering torque sensor 13. When it is determined that the vehicle is stopped, the clutch mechanism 7 is held in the connected state, and in that state, the steering motor 6 is controlled to be operated according to the steering torque detected by the steering torque sensor 13.

In this manual steering mode, if the vehicle is running, the clutch mechanism 7 is in a disengaged state, and the steering wheel 3 and the steering pinion 2 are held in a mechanically disconnected state. Then, when the driver rotates the steering wheel 3 in this state, the steering motor 6 operates according to the steering torque detected by the steering torque sensor 13, and the direction of the wheel 5 is changed only by the driving force of the steering motor 6. Change (so-called steering by wire). As a result, the relationship between the operation amount of the steering wheel 3 and the change amount of the direction of the wheel 5 can be adjusted according to the traveling state of the vehicle and the like, and an excellent steering feel can be realized.

On the other hand, in this manual steering mode, if the vehicle is stopped, the clutch mechanism 7 is in the engaged state, and the steering wheel 3 and the steering pinion 2 are held in the mechanically connected state. Then, when the driver rotates the steering wheel 3 in this state, the steering motor 6 operates according to the steering torque detected by the steering torque sensor 13, the driving force of the steering motor 6 and the steering wheel 3 by the driver. The direction of the wheel 5 changes depending on the rotational operation force of the wheel 5 (so-called power steering). This makes it possible to perform stationary steering (changing the direction of the wheels 5 while the vehicle is stopped) with a large torque. Further, when the orientation of the wheel 5 changes to the mechanical limit due to the stationary steering and the orientation of the wheel 5 does not change any more, the steering wheel 3 and the steering pinion 2 are mechanically connected. As a result, the steering wheel 3 does not rotate any more, and through this, it becomes possible to inform the driver that the direction of the wheel 5 has changed to the mechanical limit.

In this automatic steering device, the clutch mechanism 7 provided between the steering wheel 3 and the steering pinion 2 is held in the disconnected state in the automatic steering mode, so that even if the steering motor 6 operates, the steering motor 6 is maintained. The driving force of the steering wheel 3 is not transmitted to the steering wheel 3. That is, even if the direction of the wheel 5 automatically changes significantly according to the external condition of the vehicle detected by the external condition sensor 52 in the automatic steering mode, the steering wheel is linked to the direction of the wheel 5. It is possible to prevent the 3 from rotating greatly. Therefore, in the automatic steering mode, the steering wheel 3 can be prevented from being greatly rotated to prevent the driver from being injured, which is excellent in the safety of the driver.

For example, in the automatic steering mode, when an obstacle is detected in front of the vehicle in the traveling direction by the external condition sensor 52, the steering motor 6 is operated to avoid the obstacle, and the direction of the wheel 5 is changed. It can change significantly. In this case, if the steering wheel 3 rotates significantly in conjunction with the direction of the wheels 5, the driver may touch the steering wheel 3 and be injured. On the other hand, in this automatic steering device, the clutch mechanism 7 is held in the disconnected state, and the steering wheel 3 is stopped without rotating, or even if it rotates, it rotates only small due to the driving force of the reaction force motor 12. Therefore, it is possible to prevent the driver from touching the steering wheel 3 and injuring him / her.

Further, this automatic steering device employs a non-excitation actuated clutch as the clutch mechanism 7, which is in the cutoff state when energized and in the connected state when not energized. Therefore, even if the power supply related to steering is lost due to an unexpected situation, the clutch mechanism 7 is in a connected state, the steering wheel 3 and the steering pinion 2 are mechanically connected, and the steering wheel 3 is used as a wheel. It is possible to steer 5.

Further, in this automatic steering device, as a clutch mechanism 7, an engaging element type clutch (engagement elements (here,

rollers

23a and 23b) incorporated between the inner ring 21 and the outer ring 22) engages between the outer ring 22 and the inner ring 21. A clutch that switches between transmission and disconnection of rotation by moving between the engaging position that matches and the disengaging position that disengages the engagement) is adopted. Here, the engaging element type clutch has an extremely low idling torque in the disconnected state. Therefore, this automatic steering device can effectively block the transmission of the driving force of the steering motor 6 to the steering wheel 3 when the control unit 50 holds the clutch mechanism 7 in the disengaged state. It has become. This makes it possible to easily realize, for example, a steering non-rotation mode in which the steering wheel 3 does not rotate and is kept stopped even if the steering motor 6 is operated in the automatic steering mode. Further, for example, in the manual steering mode, it is possible to realize so-called steer-by-wire control in which the direction of the wheels 5 is changed only by the driving force of the steering motor 6 with high accuracy.

In the above embodiment, an engager type clutch that employs

rollers

23a and 23b as an engager to be incorporated between the inner circumference of the outer ring 22 and the outer circumference of the inner ring 21 has been described as an example, but a ball or a sprag is used as the engager. It is also possible to adopt the engaged element type clutch that has been adopted.

FIG. 10 shows an automatic steering device according to a second embodiment of the present invention. In the second embodiment, the arrangement of the steering motor 6 and the clutch mechanism 7 is different from that in the first embodiment, but the other configurations are the same as those in the first embodiment. Therefore, the parts corresponding to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

A reaction force motor 12 and a clutch mechanism 7 are provided in order from the steering wheel 3 side to the steering pinion 2 side in the middle of the rotation transmission path 4. The steering motor 6 is attached to the rack housing 8 so as to input a driving force to the steering rack 1 via the reduction gear 15. Here, the clutch mechanism 7 is arranged at the end of the rotation transmission path 4 on the steering pinion 2 side. As a result, when the clutch mechanism 7 is in the disengaged state, it is possible to disengage the transmission of the driving force of the steering motor 6 to the steering wheel 3.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Steering rack 2 Steering pinion 3 Steering wheel 4 Rotation transmission path 5 Wheel 6 Steering motor 7 Clutch mechanism 13 Steering torque sensor 21 Inner ring 22

Outer ring

23a, 23b Roller (engager)
24 Roller cage (engager cage)
29 Spring 36 Armature 37 Electromagnet 39 Motion conversion mechanism 50 Control unit 52 External status sensor

Claims

With a steering rack (1) that is movably supported in the left-right direction of the vehicle and whose left and right ends are connected to the pair of wheels (5) so that the direction of the pair of left and right wheels (5) changes according to the movement. ,
A steering pinion (2) that meshes with the steering rack (1) and
The steering wheel (3) that the driver rotates and operates,
A rotation transmission path (4) for transmitting rotation between the steering wheel (3) and the steering pinion (2),
An external condition sensor (52) that detects the external condition of the vehicle, and
A steering motor (6) that inputs a driving force to the rotation transmission path (4) or the steering rack (1) to steer the pair of wheels (5).
A manual steering mode that changes the direction of the pair of wheels (5) based on the rotation operation of the steering wheel (3) by the driver, and automatically in a state where the driver does not rotate the steering wheel (3). It has an automatic steering mode that changes the direction of the pair of wheels (5), and in the automatic steering mode, the steering motor (6) is according to the external condition of the vehicle detected by the external condition sensor (52). In the automatic steering device of the vehicle having a control unit (50) that controls to operate).
A connected state in which rotation is transmitted between the steering wheel (3) and the steering pinion (2) to the rotation transmission path (4), and between the steering wheel (3) and the steering pinion (2). A clutch mechanism (7) that can switch between the cutoff state and the cutoff state that cuts off the transmission of rotation is provided.
The clutch mechanism (7) is arranged at a position that cuts off the transmission of the driving force of the steering motor (6) to the steering wheel (3) when the clutch mechanism (7) is in the disengaged state.
The control unit (50) controls to hold the clutch mechanism (7) in the disengaged state in the automatic steering mode.
An automatic steering device for vehicles characterized by this.
Further, it has a steering torque sensor (13) for detecting the steering torque of the steering wheel (3) by the driver.
The first aspect of the present invention, wherein the control unit (50) controls to operate the steering motor (6) according to the steering torque detected by the steering torque sensor (13) in the manual steering mode. Vehicle automatic steering system.
In the manual steering mode, the control unit (50) holds the clutch mechanism (7) in the disengaged state while the vehicle is running, and the clutch mechanism (7) is in the connected state while the vehicle is stopped. The automatic steering device for a vehicle according to claim 2, wherein the vehicle is controlled to be held in the vehicle.
The automatic steering device for a vehicle according to any one of claims 1 to 3, wherein the clutch mechanism (7) is a non-excitation actuated clutch that is in the disengaged state when energized and in the connected state when not energized.
The clutch mechanism (7) is
The inner ring (21) to which the rotation of the steering wheel (3) is input, and
An outer ring (22) supported so as to be relatively rotatable with respect to the inner ring (21),
Engagement elements (23a, 23b) incorporated between the inner circumference of the outer ring (22) and the outer circumference of the inner ring (21), and
An engaging position in which the engaging element (23a, 23b) engages between the outer ring (22) and the inner ring (21), and an engaging disengagement position in which the engaging element (23a, 23b) is disengaged. With an engager cage (24) movably supported between,
A spring (29) that urges the engager cage (24) from the disengagement position toward the engagement position,
An armature (36) that is movably supported in the axial direction and
An electromagnet (37) that attracts the armature (36) in the axial direction by energization, and
An motion conversion mechanism that converts the axial movement of the armature (36) due to the energization of the electromagnet (37) into an motion of the engager cage (24) moving from the engagement position to the disengagement position. 39), and the automatic steering device for a vehicle according to any one of claims 1 to 4.
The steering motor (6) is attached so as to input a driving force to the rotation transmission path (4).
The clutch mechanism (7) is arranged between the steering wheel (3) and a position where the driving force of the steering motor (6) of the rotation transmission path (4) is input. The vehicle automatic steering device according to any one of 5 to 5.
The steering motor (6) is attached to the steering rack (1) so as to input a driving force.
The vehicle automatic steering device according to any one of claims 1 to 5, wherein the clutch mechanism (7) is arranged at an end of the rotation transmission path (4) on the side of the steering pinion (2).