JP2003276630A - Steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device for a vehicle capable of reducing energy consumption of an operation actuator, preventing overload, and maintaining excellent steering feeling. <P>SOLUTION: The motion of a steering actuator 2 is transmitted to a wheel 4 to change a steering angle without connecting an operating member 1 with a wheel 4 mechanically. The steering of the wheel 4 is prevented by a car body side member 31 when the steering quantity reaches the maximum. A connecting mechanism 30 puts an operation side member 10 mechanically connected with an operating member 1 and a wheel side member 15 mechanically connected with the wheel 4 in a condition where rotation transmission is released until the steering quantity of the wheel 4 reaches the maximum value, and connects them so that the rotation transmission is allowed when the maximum value is reached. When the connecting mechanism 30 is in a connection condition, the magnitude of the operation torque generated by the operation actuator 19 and acting in a neutral-position returning direction of the operating member 1 is made larger than zero. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system capable of changing a steering angle according to an operation of an operating member without mechanically connecting the operating member to a wheel.

[0002]

2. Description of the Related Art As a vehicle steering system capable of changing a steering characteristic of a vehicle by controlling a steering actuator, there is a vehicle steering system which employs a so-called steer-by-wire system. In a steering device that employs a steer-by-wire system, the steering actuator is controlled according to the operation of an operating member that imitates a steering wheel, and the movement of the steering actuator is controlled without mechanically connecting the operating member to the wheel. Is transmitted to the wheels so that the steering angle changes.

In a steering device employing a steer-by-wire system, steering resistance or self-aligning torque due to friction between wheels and a road surface is not transmitted to the operating member. Therefore, a steering feeling is given to the driver by providing an operating actuator that generates an operating torque that acts on the operating member.

Further, in the steering device adopting the steer-by-wire system, even if the steering amount of the wheels reaches the maximum value and the steering of the wheels is blocked, the rotation of the operating member is not blocked. Therefore, when the turning amount of the wheels reaches the maximum value, the operating actuator generates the operating torque that prevents the operating member from rotating in the direction of increasing the steering angle.

However, since a large operating torque is required to prevent the operating member from rotating, the capacity of the operating actuator becomes large. Further, when the operation actuator prevents the operation member from rotating for a long time, there is a problem that energy consumption increases and the amount of heat generated by overload increases.

Therefore, an operation side member mechanically connected to the operation member so as to rotate according to the operation of the operation member, and a mechanically connected wheel so as to rotate according to the movement of the wheel due to a change in the steering angle. An electromagnetic clutch is provided between the wheel-side member and the wheel-side member, and when the steering amount of the wheel reaches the maximum value, the operation-side member and the wheel-side member are connected via the electromagnetic clutch and the operating torque is set to zero. It has been proposed (Japanese Patent Laid-Open No. 20-200200).
01-171543). In this conventional example, when the turning amount of the wheels reaches the maximum value, the operation of the operating member in the increasing direction of the steering angle is blocked by the vehicle body side member that blocks the turning of the wheels. As a result, when the turning amount of the wheels reaches the maximum value, the operating actuator does not need to generate the operating torque.

[0007]

SUMMARY OF THE INVENTION In the above conventional example,
When operating the operating member in the direction of decreasing the steering angle from the state where the turning amount of the wheels has reached the maximum value, the operating side member and the wheel side member are initially connected due to the response delay of the electromagnetic clutch. Steering resistance based on friction between the wheels and the road surface acts on the operating member. After that, since the connection between the operation side member and the wheel side member by the electromagnetic clutch is released, the steering resistance is reduced. Further, when operating the operating member in the direction of decreasing the steering angle from the state where the turning amount of the wheels reaches the maximum value, it is necessary to raise the operating torque from zero. Therefore, the operating torque gradually increases from zero due to the response delay of the operating actuator. Since the fluctuation of the steering resistance and the fluctuation of the operating torque due to the friction between the wheel and the road surface are overlapped with each other, the fluctuation of the steering feeling becomes large, and there is a problem that the driver feels uncomfortable. It is an object of the present invention to provide a vehicle steering system that can solve the above problems.

[0008]

One of the features of the vehicle steering system of the present invention is that an operating member, a steering actuator, and the movement of the steering actuator are mechanically coupled to the wheel. Means for transmitting to the wheels so that a steering angle change occurs without any change, means for detecting the operation amount of the operating member, means for detecting the turning amount of the wheels,
A control system capable of controlling the steering actuator so that the steering angle changes in accordance with the operation of the operation member, the operation actuator, and an operation torque acting in the neutral position returning direction of the operation member are generated. As described above, the control system capable of controlling the operation actuator, the operation side member mechanically connected to the operation member so as to rotate in response to the operation of the operation member, and the steering amount of the wheels reach the maximum value. When it reaches, the vehicle body side member that prevents steering of the wheel, the wheel side member mechanically connected to the wheel so as to rotate according to the movement of the wheel due to the change in the steering angle, the operation side member and the wheel side A connection mechanism that can switch between a connection state in which a member is rotationally transmittable and a release state in which the rotation transmission is released, and whether or not the turning amount of the wheel has reached the maximum value is determined. Means and
When the connecting mechanism is in a connected state, the control mechanism is in a released state until the steering amount of the wheels reaches the maximum value, and is in a connected state when the maximum amount reaches the maximum value. The magnitude of the operating torque generated by the operating actuator is greater than zero. According to this configuration, when the turning amount of the wheels reaches the maximum value, the connecting mechanism is brought into the connected state, so that the operation side member and the wheel side member are connected so as to be capable of transmitting rotation. Thus, when the turning amount of the wheels reaches the maximum value, the operation of the operating member in the direction of increasing the steering angle can be blocked by the vehicle body side member that blocks the turning of the wheels.
When the connecting mechanism is in the connected state, it is not necessary to block the operation of the operating member in the direction of increasing the steering angle by the operating torque generated by the operating actuator. Therefore, the operating torque is reduced to reduce energy consumption. Can be reduced and overload can be prevented. Moreover, when the operating member is operated in the steering angle decreasing direction from the state where the turning amount of the wheels reaches the maximum value, the operating torque acting in the neutral position returning direction of the operating member is applied from the beginning. It is possible to prevent a response delay compared to when the operating torque is raised from zero. Therefore, the variation in steering feeling can be reduced.

When the connecting mechanism is in the connected state, the magnitude of the operating torque generated by the operating actuator is set to be equal to or smaller than the magnitude of the operating torque generated when the steering amount of the wheels is less than the maximum value. Is preferred. Thereby, energy consumption can be reduced.

A means for determining whether or not the operating actuator satisfies a set load condition, and when the load condition is not satisfied and the turning amount of the wheels reaches the maximum value, the connecting mechanism is provided. Is released, and the operation actuator is preferably controlled so as to generate an operation torque capable of preventing an operation of the operation member in the steering angle increasing direction. The load condition may be set in advance so that the load on the operating actuator does not become excessive. For example, the vehicle speed is less than or equal to a set value, the time when the steering angle is greater than or equal to the set value is greater than or equal to the set value, or It is assumed that the temperature detected by the operating actuator is above the set value.
By setting the connection mechanism in the connected state when the load condition is satisfied, it is possible to prevent the operation actuator from being overloaded.

Another feature of the vehicle steering system of the present invention is that
An operation member, a steering actuator, a means capable of transmitting the movement of the steering actuator to a wheel so as to change a steering angle without mechanically connecting the operation member to the wheel, and an operation of the operation member. And a control system capable of controlling the steering actuator so that the steering angle changes in accordance with the operation of the operation member, and a means for detecting the steering amount of the wheel When,
A control system that can control the operating actuator so as to generate an operating torque that acts in the direction of returning the operating member to the neutral position, and a mechanical operation of the operating member that rotates in response to the operation of the operating member. When the operation side member connected and the turning amount of the wheel reach the maximum value, the vehicle body side member that prevents the turning of the wheel and the operation amount of the operation member are set limit values, A stopper provided on the vehicle body side so as to prevent the operation side member from rotating in the direction of increasing the steering angle, and when the operation amount of the operation member reaches the limit value, the turning amount of the wheels becomes the maximum value or less. As such, the limit value is set. With this configuration, when the operation amount of the operation member reaches the limit value, the rotation of the operation side member can be blocked by the stopper. At this time, since the operating actuator does not need to generate the operating torque, the operating torque can be reduced to reduce energy consumption and prevent overload. Moreover, since the steering resistance based on the friction between the wheel and the road surface does not act on the operating member, the variation in the steering feeling can be reduced.

When the stopper blocks the rotation of the operation side member, the magnitude of the operation torque generated by the operation actuator is the magnitude of the operation torque generated when the operation amount of the operation member is less than the limit value. It is preferably less than or equal to zero and less than zero. . As a result, when operating the operating member in the direction of decreasing the steering angle, the operating torque acting in the direction of returning the neutral position of the operating member is applied from the beginning, and a response delay is prevented compared to when the operating torque is raised from zero. However, variations in steering feeling can be further reduced.

The stopper is provided with means for determining whether or not the operating actuator satisfies a set load condition, and when the load condition is not satisfied and the operation amount of the operating member reaches a limit value. It is preferable that the operation side member is displaced to a position that does not prevent rotation of the operation side member, and that the operation actuator is controlled so as to generate an operation torque that can prevent operation of the operation member in the steering angle increasing direction. This can prevent overload of the operating actuator.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A steering device for a vehicle according to a first embodiment shown in FIG. 1 includes an operating member 1 simulating a steering wheel.
A steering actuator 2 and a steering gear 3 for transmitting the movement of the steering actuator 2 to the wheels 4 so as to change the steering angle without mechanically connecting the operating member 1 to the wheels 4. .

The steering actuator 2 can be constituted by an electric motor such as a known DC brushless motor. The steering gear 3 has a motion conversion mechanism that converts the rotational motion of the output shaft of the steering actuator 2 into the linear motion of the steering rod 7. The toe angle of the wheel 4 is changed by transmitting the movement of the steering rod 7 to the wheel 4 via the tie rod 8 and the knuckle arm 9. A known gear can be used as the steering gear 3, and the structure is not limited as long as the movement of the steering actuator 2 can be transmitted to the wheels 4 so that the steering angle changes. In the present embodiment, the steering actuator 2
The steering rod 7 is formed with a rack 7a that meshes with the pinion 2a attached to the output shaft of the. When the steering actuator 2 is not driven, the wheel alignment is set so that the wheels 4 can return to the straight-ahead position by the self-aligning torque.

The operating member 1 is connected to an input side rotating shaft 10 rotatably supported by the vehicle body so as to rotate together. As a result, in the present embodiment, the input side rotation shaft 10 is the operation side member. The operation side member may be mechanically connected to the operation member 1 so as to rotate according to the operation of the operation member 1, and may be connected via, for example, a transmission gear mechanism. The input side rotary shaft 10 is provided with an operation actuator 19
The output shaft of is integrated. The operating actuator 19 can generate an operating torque.
The operating actuator 19 can be configured by an electric motor such as a brushless motor.

An angle sensor 11 for detecting an operation angle δh as an operation amount of the operation member 1 is provided. A steering angle sensor 13 that detects a steering angle δ as a steering amount of the wheels 4 is provided. In the present embodiment, the steering angle sensor 13 is configured by a sensor that detects the amount of movement of the steering rod 7 from the steering angle midpoint as the steering angle δ. A speed sensor 14 that detects the vehicle speed V is provided. A torque sensor 12 that detects the torque transmitted by the input side rotating shaft 10 as the operation torque Th corresponding to the operation torque of the operation member 1 is provided. The angle sensor 11, the torque sensor 12, the rudder angle sensor 13, and the speed sensor 14 are connected to a control device 20 including a computer.

The control device 20 constitutes a control system for controlling the steering actuator 2 via the drive circuit 22 so that the steering angle changes according to the operation of the operating member 1. For example, the control device 20 controls the operation angle δh of the operation member 1 and the vehicle speed V.
The relationship between the target steering angle δ ^* and the target steering angle δ ^* is predetermined and stored, and the drive signal of the steering actuator 2 is output to the drive circuit 22 so as to eliminate the deviation between the target steering angle δ ^* and the detected steering angle δ.
The relationship between the operation angle δh, the vehicle speed V, and the target steering angle δ ^* is, for example, to improve the turning performance at a low vehicle speed and improve the running stability at a high vehicle speed. δ
The ratio δ ^* / δh of the target steering angle δ ^{* to} h is set to be small. Thereby, the ratio of the operation angle δh and the steering angle δ,
That is, the steering actuator 2 is controlled so that the ratio between the operation amount of the operation member 1 and the turning amount of the wheels 4 changes.
The ratio δ ^* / δh is not limited to the one that changes according to the vehicle speed V, and may change, for example, according to the operating speed or the operating angle, and the steering actuator 2 is controlled so that the ratio changes. can do.

The control device 20 constitutes a control system for controlling the operating actuator 19 via the drive circuit 23.
By controlling the operating actuator 19, an operating torque that acts in a direction of returning the operating member 1 to the neutral position can be generated according to the vehicle operating conditions. The operating condition is, for example, the operation angle δh, and the control device 20 calculates the target operation torque Th ^* as the operation torque target value correlated with the operation angle δh. For example, the control device 20 stores the relationship that the target operation torque Th ^* increases as the operation angle δh increases, and the stored relationship and the detected operation angle δh.
The target operation torque Th ^* is calculated from the above, and the drive signal of the operation actuator 19 is output to the drive circuit 23 so as to eliminate the deviation between the target operation torque Th ^* and the detected operation torque Th. The vehicle operating condition is not limited to the operation angle δh, and for example, the operation angle δh and the vehicle speed V are set to the target operation torque Th.
^{* May} be correlated, as long as an appropriate operating torque can be generated.

A pinion 15a that meshes with the rack 7a.
Further, an output side rotation shaft 15 is connected as a wheel side member so as to rotate together. The output side rotary shaft 1
It suffices that 5 is mechanically connected to the wheel 4 so as to rotate according to the movement of the wheel due to the change in the steering angle, and the connection with the wheel 4 is not limited to that via the rack 7a and the pinion 15a.

The input side rotating shaft 10 and the output side rotating shaft 15 are connected via a connecting mechanism 30. In the present embodiment, the connecting mechanism 30 is composed of an electromagnetic clutch connected to the control device 20, and is in a connected state in which the input side rotating shaft 10 and the output side rotating shaft 15 are connected in a rotationally transmissible manner, and its rotational transmission. It is possible to switch between the released state and the released state.

A vehicle body side member 31 is mounted on the vehicle body side to prevent the steering rod 7 from moving when the steering amount of the wheels 4 reaches the maximum value and the steering angle becomes maximum. The structure of the vehicle body side member is not particularly limited as long as it can prevent the turning of the wheels 4 when the turning amount of the wheels 4 reaches the maximum value. The control device 20 determines whether or not the turning amount of the wheels 4 has reached the maximum value from the steering angle δ detected by the steering angle sensor 13.

The control device 20 controls the connecting mechanism 30 to be in the released state until the turning amount of the wheels 4 reaches the maximum value, and to be in the connected state when the maximum amount is reached. When the connecting mechanism 30 is in the connected state, the magnitude of the operating torque generated by the operating actuator 19 is equal to or less than the magnitude of the operating torque generated when the turning amount of the wheels 4 is less than the maximum value. Is set to be larger than zero, for example, the magnitude of the operating torque generated immediately before the turning amount of the wheels 4 reaches the maximum value.

The control procedure of the steering actuator 2 and the operation actuator 19 by the control device 20 of the first embodiment will be described with reference to the flowchart of FIG. First,
The value detected by each sensor is read (step S1), and it is determined whether or not the magnitude of the detected steering angle δ is less than the set maximum value δmax (step S2). If the magnitude of the detected steering angle δ has not reached the maximum value δmax, the coupling mechanism 30 is released (step S3), and the target steering angle δ ^* is calculated from the detected operation angle δh and the detected vehicle speed V as described above ( Step S4),
The steering actuator 2 is controlled so as to eliminate the deviation between the target steering angle δ ^* and the detected steering angle δ (step S5). As a result, the steering actuator 2 is controlled so that the ratio between the operation amount of the operation member 1 and the turning amount of the wheels 4 changes.
Further, the target operation torque T ^* is obtained from the detected operation angle δh as described above (step S6), and the target operation torque T ^* is obtained ^.
The operating actuator 19 is controlled so as to eliminate the deviation between the detected operating torque Th (step S7). Then, it is determined whether or not the control is ended, for example, by whether or not the ignition switch is off (step S8), and if not ended, the process returns to step S1. If the magnitude of the detected steering angle δ reaches the maximum value δmax in step S2, the coupling mechanism 30 is brought into the coupled state (step S9), and the magnitude of the operating torque is such that the turning amount of the wheels 4 is less than the maximum value. The operating actuator 19 is controlled so that the set value is equal to or smaller than the value that sometimes occurs and is larger than zero (step S10). After that, it is determined whether or not to end the control (step S8).

According to the first embodiment, when the turning amount of the wheels 4 reaches the maximum value, the connecting mechanism 30 connects the input side rotating shaft 10 and the output side rotating shaft 15 so that rotation can be transmitted. As a result, when the turning amount of the wheels 4 reaches the maximum value, the operation of the operating member 1 in the steering angle increasing direction can be blocked by the vehicle body side member 31 that blocks the turning of the wheels 4.
When the connecting mechanism 30 is in the connected state, it is not necessary to block the operation of the operating member 1 in the direction of increasing the steering angle by the operating torque generated by the operating actuator 19, so the operating torque is reduced and energy consumption is reduced. Can be reduced and overload can be prevented. In this case, energy consumption can be reduced by setting the magnitude of the operating torque to be equal to or smaller than the magnitude of the operating torque generated when the turning amount of the wheels is less than the maximum value. Moreover, when the operating member 1 is operated in the steering angle decreasing direction from the state where the turning amount of the wheels 4 reaches the maximum value, the operating torque acting in the neutral position returning direction of the operating member 1 is applied from the beginning. Therefore, the response delay can be prevented as compared with the case where the operating torque is raised from zero. Therefore, the variation in steering feeling can be reduced.

As a modification of the first embodiment, the control device 20 determines whether or not the operating actuator 19 satisfies the set load condition, and the load condition is not satisfied and the steering amount of the wheel 4 is changed. When the maximum value is reached, the coupling mechanism 30
May be released, and the operation actuator 19 may be controlled so as to generate an operation torque capable of blocking the operation of the operation member 1 in the steering angle increasing direction. In this case, if the magnitude of the detected steering angle δ reaches the maximum value δmax, it is determined whether or not the load condition is satisfied, and if the load condition is satisfied, the connection mechanism is the same as in the first embodiment. The operation actuator 19 may be controlled so that the operation torque is equal to or less than the value that occurs when the steering amount of the wheels 4 is less than the maximum value. If the load condition is not satisfied, the coupling mechanism 30 is released and the magnitude of the operating torque is made equal to the magnitude of the detected torque Th of the torque sensor 12 to increase the steering angle of the operating member 1. Operation can be blocked. The load conditions are, for example, that the detected vehicle speed V is less than or equal to a set value, that the detected steering angle δ is greater than or equal to a set value that exceeds the play range near the midpoint, or is greater than or equal to the set value.
The temperature sensor is provided, and the detected temperature is equal to or higher than the set value. By satisfying the load condition, the connecting mechanism 30
By making the connection state, the operation actuator 19 can be prevented from being overloaded.

FIG. 3 shows a vehicle steering system according to the second embodiment. The same parts as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Differences will be described. In the second embodiment, the input side rotary shaft 1 connected to the operation member 1
0 is integrally provided with a first gear 51.
The second gear 52 meshing with the first gear 1 is rotatably supported by the vehicle body. The second gear 52 is an operation side member in the present embodiment. When the operation amount of the operation member 1 is the set limit value, the stopper 53 is provided on the vehicle body side so as to prevent the rotation of the second gear 52 in the steering angle increasing direction.
Is provided. The stopper 53 blocks rotation of the second gear 52 by coming into contact with the protruding portion 52a attached to the second gear 52 in the present embodiment. For example, the operating member 1 is rotated 360 degrees to the right or left from the straight-ahead position.
The rotation causes the protruding portion 52 a to come into contact with the stopper 53. In the present embodiment, the rotation of the operating member 1 is decelerated and transmitted from the first gear 51 to the second gear 52, but it is not always necessary to decelerate. Further, the rotation of the operating member 1 may be directly blocked by the stopper without using the gear. The limit value is set so that the steering amount of the wheels 4 becomes equal to or less than the maximum value when the operation amount of the operation member 1 reaches the limit value. In this embodiment, when the vehicle speed V is zero, the ratio δ ^* / δh of the target steering angle δ ^* to the operation angle δh.
Is the maximum, the magnitude of the operating angle δh of the operating member 1 when the magnitude of the steering angle δ reaches the maximum value when the vehicle speed V is zero corresponds to the limit value. Further, in this embodiment, the output side rotation shaft 15 and the coupling mechanism 30 in the first embodiment are not provided. In the present embodiment, when the rotation of the second gear 52 in the steering angle increasing direction is blocked by the stopper 53, the magnitude of the operating torque generated by the operating actuator 19 is zero.

The control procedure of the steering actuator 2 and the operation actuator 19 by the control device 20 of the second embodiment will be described with reference to the flowchart of FIG. First,
The value detected by each sensor is read (step S10).
1) It is determined whether or not the magnitude of the detected operation angle δh is less than the limit value δhmax (step S102). If the magnitude of the operation angle δh has not reached the limit value δhmax, the target steering angle δ ^* is calculated from the detected operation angle δh and the detected vehicle speed V (step S103), and the target steering angle δ is determined, as in the first embodiment. ^*
The steering actuator 2 is controlled so as to eliminate the deviation between the detected steering angle δ and the detected steering angle δ (step S104).
The target operating torque T ^* is obtained from the (step S105),
The operation actuator 19 is controlled so as to eliminate the deviation between the target operation torque T ^* and the detected operation torque Th (step S106), and it is determined whether the control is to be ended (step S107). S101
Return to. If the magnitude of the detected operation angle δh reaches the limit value δhmax in step S102, the drive of the operation actuator 19 is released (step S108), and it is determined whether or not the control is ended (step S107).

According to the second embodiment described above, when the operation amount of the operation member 1 reaches the limit value, the rotation of the second gear 52 can be blocked by the stopper 53. At this time, since the operating actuator 19 does not need to generate an operating torque, energy consumption can be reduced and overload can be prevented. Moreover,
Since the steering resistance based on the friction between the wheels 4 and the road surface does not act on the operating member 1, the fluctuation of the steering feeling can be reduced.

As a modified example of the second embodiment, a means for judging whether or not the operating actuator 19 satisfies the set load condition is provided, and the load condition is not satisfied and the operation amount of the operating member 1 is changed. When the limit is reached, stopper 53
May be displaced to a position that does not block the rotation of the second gear 52, and the operating actuator 19 may be controlled to generate an operating torque that can block the operation of the operating member 1 in the steering angle increasing direction. . The stopper 53 is displaced, for example, by an electric actuator between a position that blocks rotation of the second gear 52 and a position that does not block rotation of the second gear 52. In this case, if the magnitude of the detected operation angle δh reaches the limit value δhmax, it is determined whether the load condition is satisfied, and if the load condition is satisfied, the stopper 53 is driven by the electric actuator to the second gear 52. Of the operating actuator 1 in the same manner as in the second embodiment.
The drive of 9 is released. If the load conditions are not met,
The stopper 53 is connected to the second gear 5 by the electric actuator.
The operation member 1 is prevented from being operated in the direction of increasing the steering angle by displacing the rotation member 2 to a position that does not prevent rotation and making the magnitude of the operating torque equal to the magnitude of the detected torque Th of the torque sensor 12. The load condition can be the same as that of the modification of the first embodiment. It is possible to prevent the operation actuator 19 from being overloaded by releasing the operation of the operation actuator 19 when the load condition is satisfied.

In the second embodiment and its modification, the second
When the rotation of the gear 52 in the direction of increasing the steering angle is blocked by the stopper 53, the magnitude of the operating torque generated by the operating actuator 19 is set to an operation amount generated when the operation amount of the operating member 1 is less than the limit value. It may be less than the magnitude of the working torque and greater than zero. Thereby, the operation member 1
When operating the steering wheel in the direction of decreasing the steering angle, the operation torque acting in the direction of returning the neutral position of the operation member 1 is applied from the beginning to prevent a response delay as compared with the case where the operation torque is raised from zero, and the steering torque is reduced. The fluctuation of the ring can be further reduced.

The present invention is not limited to the above-described embodiments and modifications. For example, the fail-safe function may be achieved by connecting the operation-side member and the wheel-side member via the connecting mechanism when a failure or operation abnormality of the steering actuator or the control system occurs. Further, the connecting mechanism is not limited to the electromagnetic clutch, as long as it can be switched between a connected state in which the operation side member and the wheel side member are rotatably transmitted and a released state in which the rotation transmission is released. The rotation transmission ratio between the operation side member and the wheel side member may be other than 1 in the connected state. For example, a sun gear connected to one of the operation side member and the wheel side member, a carrier connected to the other, a ring gear meshing with the sun gear and a planetary gear supported by the carrier, and rotation of the ring gear. A lock member that is displaced between a locked position and an unlocked position and an electric actuator that displaces the lock member are provided, and the lock member is displaced to the lock position in the coupled state and to the unlocked position in the released state. The electric actuator may be controlled so as to be displaced to.

[0033]

According to the present invention, in a vehicle steering system adopting a steer-by-wire system, energy consumption of an operating actuator is reduced and overload is prevented.
It is possible to maintain a good steering feeling when the steering angle is reduced after steering to the maximum steering angle.

[Brief description of drawings]

FIG. 1 is a structural explanatory diagram of a vehicle steering system according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of the control device in the vehicle steering system according to the first embodiment of the present invention.

FIG. 3 is a configuration explanatory view of a vehicle steering system according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing a control procedure of a control device in a vehicle steering system according to a second embodiment of the present invention.

[Explanation of symbols]

1 Operation member 2 Steering actuator 3 steering gear Four wheels 10 Input side rotating shaft 11 Angle sensor 13 Rudder angle sensor 15 Output side rotating shaft 19 Operation actuator 20 Control device 30 connection mechanism 31 Body side member 52 Second gear 53 Stopper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B62D 113: 00 B62D 113: 00 119: 00 119: 00 (72) Inventor Takeo Iino Chuo-ku, Osaka City, Osaka Prefecture Minamisenba 3-5-8 Koyo Seiko Co., Ltd. F term (reference) 3D032 CC08 DA02 DA03 DA15 DA23 DB11 DC34 DD02 DE02 EB11 EC22 GG01 3D033 CA13 CA16 CA17 CA18 CA21

Claims (6)

[Claims] 1. An operating member, a steering actuator, and a means capable of transmitting the movement of the steering actuator to a wheel so as to change a steering angle without mechanically connecting the operating member to the wheel. A means for detecting the operation amount of the operation member, a means for detecting the turning amount of the wheel, and a control system capable of controlling the steering actuator so that the steering angle changes according to the operation of the operation member. A control system capable of controlling the operating actuator so as to generate an operating torque acting on the operating actuator in the direction of returning the neutral position of the operating member, and rotating the operating member according to the operation of the operating member. The operation side member mechanically connected to the operation member, the vehicle body side member that prevents the turning of the wheel when the turning amount of the wheel reaches the maximum value, and the movement of the wheel due to the change in the steering angle. Rotate As described above, a wheel-side member mechanically connected to the wheel, a connection state in which the operation-side member and the wheel-side member are connected in a rotationally transmittable state, and a release state in which the rotation transmission is released can be switched. The mechanism, the means for determining whether or not the turning amount of the wheels has reached the maximum value, and the connecting mechanism are in the released state until the turning amount of the wheels reaches the maximum value, and have reached the maximum value. A steering apparatus for a vehicle, comprising: a controllable means so that the steering mechanism is sometimes in a connected state, and the operating torque generated by the operating actuator is greater than zero when the connecting mechanism is in the connected state. 2. When the connecting mechanism is in the connected state, the magnitude of the operating torque generated by the operating actuator is equal to or less than the magnitude of the operating torque generated when the turning amount of the wheels is less than the maximum value. The vehicle steering apparatus according to claim 1, wherein the steering apparatus is a vehicle. 3. A means for determining whether or not the operating actuator satisfies a set load condition, and when the load condition is not satisfied and the wheel steering amount reaches a maximum value, The vehicle according to claim 1 or 2, wherein the connecting mechanism is in a released state, and the operation actuator is controlled so as to generate an operation torque capable of preventing an operation of the operation member in the steering angle increasing direction. Steering device. 4. An operating member, a steering actuator, and a means capable of transmitting the movement of the steering actuator to a wheel so as to change a steering angle without mechanically connecting the operating member to the wheel. A means for detecting the operation amount of the operation member, a means for detecting the turning amount of the wheel, and a control system capable of controlling the steering actuator so that the steering angle changes according to the operation of the operation member. A control system capable of controlling the operating actuator so as to generate an operating torque acting on the operating actuator in the direction of returning the neutral position of the operating member, and rotating the operating member according to the operation of the operating member. The operation side member mechanically connected to the operation member, the vehicle body side member that prevents the wheel from turning when the steering amount of the wheel reaches the maximum value, and the operation amount of the operation member are set. At the limit In order to prevent the rotation of the operating side member in the direction of increasing the steering angle, a stopper provided on the vehicle body side is provided, and when the operating amount of the operating member reaches the limit value, the steering amount of the wheel is maximum. The steering device of the vehicle, the limit value of which is set to be less than or equal to the value. 5. The magnitude of the operating torque generated by the operating actuator when the stopper blocks the rotation of the operating member is equal to the operating torque generated when the operating amount of the operating member is less than the limit value. The vehicle steering system according to claim 4, wherein the steering system is less than or equal to the size and greater than zero. 6. A means for determining whether or not the operation actuator satisfies a set load condition, and when the load condition is not satisfied and the operation amount of the operation member reaches a limit value, The stopper is displaced to a position that does not prevent rotation of the operation side member, and the operation actuator is controlled so as to generate an operation torque that can prevent operation of the operation member in the direction of increasing the steering angle. Alternatively, the vehicle steering system according to the fifth aspect.