JP2005178460A - Steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change between the stationary state where a rotation allowance amount of a steering member 1 is restricted and the special state not restricting it, and to enlarge steering function, in a steering device for a vehicle of a steer-by-wire system. <P>SOLUTION: The steering device for the vehicle is provided with a rotation restriction mechanism 15 capable of changing from a neutral position of the steering member 1 to the stationary state restricting left and right rotation allowance amount and the special state not restricting the rotation allowance amount of the steering member 1. The rotation restriction mechanism 15 can be controlled, if necessary, by a control device 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle steering apparatus for a so-called steer-by-wire system in which a steering member and a steering mechanism are not mechanically connected.

  The above steer-by-wire system does not mechanically connect a steering member such as a steering wheel and a steering mechanism of a pair of left and right wheels, and does not mechanically connect the steering member such as the rotation direction or rotation angle of the steering member, or the vehicle traveling state such as engine output. In this system, steering is performed by controlling a steering actuator by a control device based on driving information and driving a steering mechanism.

In the steering device for a vehicle of this steer-by-wire system, on the steering member side, a rotation allowable amount setting means for setting a left and right rotation allowable amount from the neutral position of the steering member is provided (for example, see Patent Document 1). The rotation allowance setting means is provided on the side of the steering shaft connected to the steering member, and the moving body that moves following the rotation of the steering shaft and the movement allowance of the moving body in contact with the moving body are set. It consists of two blocking parts to be set. It should be noted that the position of one of the two blocking portions can be changed so that the rotation allowable amount of the steering shaft can be changed.
JP-A-10-194152

  In the above conventional example, the allowable rotation amount of the steering shaft can be changed, but the rotation of the steering shaft cannot be made unlimited. There is a demand for enabling such a free state.

  By the way, in the vehicle steering apparatus of the steer-by-wire system, when the steering actuator for driving the steering mechanism fails, the fail safe allows the steering mechanism to be operated directly by the operation of the steering member by the driver. It is desired to have a function. The fail-safe function is performed by a switching mechanism that switches a steering shaft connected to the steering member and a steered shaft connected to the steering mechanism of the wheel between a mechanically disconnected state and a mechanically connected state. It is possible. However, in this case, for example, in a situation where the steering actuator is in a disconnected state and control is performed so as to shift the phase between the neutral position of the steering member and the neutral position of the steering mechanism by the steering actuator, If the switching mechanism switches to the connected state along with the failure detection, the phase between the neutral position of the steering member and the neutral position of the steering mechanism remains shifted. In that case, the rotation allowable amount of the steering shaft is unbalanced on the left and right.

  The present invention is a vehicle steering apparatus in which a steering member and a steering mechanism are not mechanically connected, and the allowable rotation amount of the steering member can be changed between a steady state that restricts and a special state that does not restrict It is characterized by having a rotation restricting mechanism. Here, the steering member only needs to be operated by the driver, and its outer shape is not particularly limited.

  In the present invention, since the steering member and the steering mechanism are not mechanically coupled, the steering angle is adjusted by driving the steering mechanism of the wheel by the steering actuator regardless of the steering of the steering member. It is possible. Moreover, since it is possible to select the case where the rotation allowable amount of the steering member is restricted or the case where it is not restricted as necessary, the steering function can be expanded.

  The rotation restricting mechanism receives the moving piece integrally formed so as to project radially outward at a predetermined position in the circumferential direction of the steering shaft connected to the steering member, and the moving piece rotating together with the steering shaft. And a drive mechanism that places the stopper in the turning locus of the moving piece to bring it into the steady state or places the stopper outside the turning locus of the moving piece to bring it into the special state, if necessary. Can be. In this case, it is possible to change between the steady state and the special state with a simple configuration by simply displacing the stopper.

  Further, the vehicle steering device mechanically disconnects the sensor that detects the vehicle operating state, the steering actuator that drives the steering mechanism, the steering member, and the steering mechanism in addition to the rotation restriction mechanism. A switching mechanism that switches between a state and a connected state, and a control device that controls the steering by driving the steering mechanism by controlling the steering actuator, and the control device steers based on the output of the sensor When the actuator failure is detected, the switching mechanism is driven to connect the steering member and the steering mechanism, and the rotation restricting mechanism can be set to a special state. In this case, the steering member and the steering mechanism can be switched between a mechanically disconnected state and a connected state. For example, when the steering actuator fails, the steering mechanism can be driven directly by the steering member, so that fail-safe is possible, and when the steering mechanism is directly driven by the steering member, The rotation allowance is not limited.

  In such a configuration of the present invention, for example, when the steering member and the steering mechanism are mechanically disconnected and the rotation restricting mechanism is in a steady state, the steering member There is a case where control is performed such that the phase between the neutral position and the neutral position of the steering mechanism is shifted. In such a situation, when the steering actuator fails, the control device operates the switching mechanism to switch to a state in which the steering member and the steering mechanism are mechanically connected. Although the phase with the neutral position remains shifted, in the present invention, at this time, since the rotation restriction mechanism does not restrict the steering shaft rotation tolerance, the steering shaft rotation tolerance is left and right. There will be no imbalance. Thus, even in a special situation where the steering mechanism is directly driven by the steering member, the wheel can be steered to the end in the left-right direction.

  According to the present invention, the steering function can be expanded because it is possible to change between a steady state that restricts the allowable rotation amount of the steering member and a special state that does not restrict the allowable rotation amount.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration explanatory view of a vehicle steering apparatus, FIG. 2 is a cross-sectional view of the rotation restricting mechanism of FIG. 1, and FIG. 3 is a plan view of the rotation restricting mechanism of FIG.

  The vehicle steering apparatus of the illustrated example does not mechanically connect the steering member 1 such as a steering wheel and the steering mechanism 3 of the pair of left and right wheels 2 and 2, and the steering situation such as the rotation direction and the rotation angle of the steering member 1. A steer-by-wire system that performs steering by controlling the steering actuator 5 by the control device 4 and driving the steering mechanism 3 on the basis of vehicle running conditions such as engine output and other driving information. Further, the vehicle steering apparatus mechanically connects the steering member 1 and the steering mechanism 3 by the switching mechanism 6 when the steering actuator 5 fails, and directly steers by the operation of the steering member 1 by the driver. It has a fail-safe function that allows the mechanism 3 to be driven.

  Although not shown in detail, the steering mechanism 3 is composed of a rack and pinion type or ball nut type gear box or the like, and changes the direction of the wheel 2 via the knuckle arm 8 by pushing and pulling the tie rod 7. is there.

  The control device 4 is an electronic control unit (ECU) that controls the overall known steering operation based on the output of a sensor that detects the vehicle operating state. As the sensor, a steering angle sensor 9a that detects the rotation angle of the steering member 1 and outputs information indicating the value of the rotation angle, a vehicle speed sensor 9b that detects the vehicle speed and outputs information indicating the value of the vehicle speed, In addition, an engine rotation sensor 9c that detects the rotation state of the engine of the vehicle and outputs information indicating the value of the rotation state may be used.

  The steering actuator 5 is controlled by the control device 4 to drive the steering mechanism 3, and is, for example, a brushless electric motor.

  The switching mechanism 6 includes a steering shaft 10 connected to the steering member 1 and a steering shaft 11 connected to the steering mechanism 3 in a relative rotational state, that is, a mechanically unconnected state, and an integral rotational state. In other words, the clutch is switched to a mechanically coupled state, and an appropriate clutch is obtained. Note that a reaction force actuator 12 is provided on the steering member 1 side in order to apply a road surface reaction force accompanying the steering of the steering member 1 to the steering shaft 10 in the disconnected state. The reaction force actuator 12 is a brushless electric motor, for example, and is driven by the control device 4.

  Incidentally, a rotation restricting mechanism 15 is provided on the steering member 1 side. The rotation restricting mechanism 15 sets a left and right rotation allowable amount from the neutral position of the steering member 1, and includes a moving piece 16, a stopper 17, and a drive mechanism 18.

  The moving piece 16 is integrally formed so as to project radially outward at a predetermined position in the circumferential direction of the steering shaft 10. The stopper 17 receives the moving piece 16 that rotates together with the steering shaft 10. The moving piece 16 and the stopper 17 are covered with a case 19.

  If necessary, the drive mechanism 18 is arranged in a steady state in which the stopper 17 is disposed within the turning locus of the movable piece 16 as indicated by a two-dot chain line in FIG. 2 is arranged outside the turning trajectory of the moving piece 16 as shown by a solid line in FIG. 2 to enter a special state in which the allowable rotation amount of the steering shaft 10 is not restricted.

  The drive mechanism 18 includes a drive source 21 that displaces the stopper 17 and an elastic member 22 that elastically urges the stopper 17 to be disposed at the position in the special state. The drive source 21 includes a plunger-type solenoid and includes an exciting coil 23 and a movable iron core 24. A stopper 17 is attached to the tip of the movable iron core 24. The elastic member 22 includes a compression coil spring disposed on the outer periphery of the movable iron core 24 and elastically urges the movable iron core 24 to be drawn into the inner peripheral portion of the excitation coil 23. That is, the drive mechanism 18 causes the movable iron core 24 to jump out of the inner peripheral portion of the excitation coil 23 against the urging force of the elastic member 22 by causing the control device 4 to directly flow current to the excitation coil 23 of the drive source 21. To work.

  Next, the operation will be described.

  Since the operations relating to the control of the steering actuator 5 and the reaction force actuator 12 in a state where the steering member 1 and the steering mechanism 3 are mechanically disconnected are known, detailed description thereof is omitted here. To do.

  However, when the steering actuator 5 and the reaction force actuator 12 are controlled, the drive mechanism 18 of the rotation restricting mechanism 15 is energized to turn the stopper 17 on the trajectory of the movable piece 16 as shown by the two-dot chain line in FIG. A steady state is set in which the allowable rotation amount of the steering shaft 10 is regulated. In this steady state, the stopper 17 is disposed at a predetermined position that is specified in advance with respect to the neutral position of the steering shaft 10, so that the allowable rotation amount of the steering shaft 10 can be regulated equally to the left and right.

  In such a disconnected state, the control device 4 controls the steering actuator 5 based on the rotation angle of the steering shaft 10 detected by the steering angle sensor 9a to drive the steering mechanism 3. As a driving form, the steered shaft 11 may be rotated in synchronization with the steering shaft 10, but special control for driving the steering mechanism 3 is performed regardless of the operation of the steering member 1 by the driver. Is possible. For example, when the transmission ratio is changed in accordance with the vehicle speed, the posture of the vehicle is stabilized in a situation where the wheels 2 are likely to slip, the steering angle is corrected in a situation where the vehicle is likely to overrun with a curve, Furthermore, this is performed when the steering angle is corrected so that the vehicle returns to the lane in a situation where the lane is likely to protrude.

  In such a situation where the steering actuator 5 is being controlled, the control device 4 is constantly or periodically based on information input from the various sensors 9a to 9c, etc. Monitor for failure.

  Here, for example, when the control device 4 detects a failure of the turning actuator 5, the switching mechanism 6 is driven to mechanically connect the steering shaft 10 and the turning shaft 11. Further, the energization of the drive mechanism 18 is stopped, and the stopper 17 is arranged outside the turning locus of the moving piece 16 as shown by the solid line in FIG. As a result, the steering mechanism 3 can be directly driven by the operation of the steering member 1 by the driver. In addition, in this situation, the integrally connected steering shaft 10 and the steered shaft 11 can be rotated without being restricted by the rotation restricting mechanism 15, so that the wheel 2 can be turned in the left and right steering angle ends (maximum steering angle). It becomes possible to steer to the angle.

  As described above, when the steering actuator 5 that drives the steering mechanism 3 fails, the steering member 1 can be directly driven by the steering member 1 and the allowable rotation amount of the steering member 1 is restricted. Since it cancels | releases, the safety | security and reliability of a steering device can be improved.

  By the way, when the special control mentioned above is performed, the phase of the neutral position of the steering member 1 and the neutral position of the steering mechanism 3 may shift | deviate. In such a situation, when the steering actuator 5 fails, the control device 4 operates the switching mechanism 6 to switch to the state in which the steering member 1 and the steering mechanism 3 are mechanically connected. The phase between the neutral position and the neutral position of the steering mechanism 3 remains shifted. However, at this time, since the rotation restricting mechanism 15 makes a special state in which the allowable rotation amount of the steering shaft 10 is not restricted, the allowable rotation amount of the steering shaft 10 does not become unbalanced in the left-right direction. Thus, even in a special situation where the steering mechanism 3 is directly driven by the steering member 1, the wheel 2 can be steered to the end in the left-right direction.

  Moreover, when the drive mechanism 18 is configured to be in a special state when the drive source 21 is not energized as in the above-described embodiment, the following effects are obtained. In other words, if the control device 4 and the turning actuator 5 become incapable of functioning due to the charging voltage of the on-vehicle battery being less than the specified value, the control device 4 normally energizes the drive source 21. Although it is stopped and not driven, since the control device 4 becomes incapable of functioning, the drive source 21 is not energized as a result. In that case, the rotation restricting mechanism 15 is preferably in a special state in which the rotation of the steering member 1 is not restricted, and as a result is in a correct state in terms of control. However, although such an effect cannot be obtained, the drive mechanism 18 may be configured to be in a steady state when not energized while in a special state when energized.

  Hereinafter, other embodiments of the present invention will be described.

  (1) The steered actuator 5 and the reaction force actuator 12 may be, for example, a motor with a brush or an electric motor of each known type in addition to a brushless motor.

  (2) Although various known clutches can be applied to the switching mechanism 6, in short, it is possible to switch between a state in which the two shafts are mechanically disconnected so as to be relatively rotatable and a state where they are connected so as to be integrally rotatable. Anything that has a special function can be used.

Configuration explanatory diagram of a vehicle steering apparatus according to the present invention Sectional view of the rotation restricting mechanism of FIG. FIG. 2 is a plan view of the rotation restricting mechanism of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering member 2 Wheel 3 Steering mechanism 4 Control apparatus 5 Steering actuator 6 Switching mechanism 10 Steering shaft 11 Steering shaft 15 Rotation restricting mechanism 16 Moving piece 17 Stopper 18 Drive mechanism

Claims (3)

A vehicle steering apparatus in which a steering member and a steering mechanism are not mechanically connected,
A vehicle steering apparatus comprising: a rotation restricting mechanism that enables a rotation allowable amount of the steering member to be changed between a steady state that restricts and a special state that does not restrict. The rotation restricting mechanism includes a moving piece integrally formed so as to project radially outward at a predetermined position in a circumferential direction of a steering shaft coupled to a steering member,
A stopper capable of receiving a moving piece that rotates with the steering shaft;
A drive mechanism is provided that places the stopper within the turning trajectory of the moving piece as needed and places the stopper in the steady state or puts the stopper outside the turning trajectory of the moving piece to enter the special state. The vehicle steering apparatus according to claim 1. A sensor that detects a vehicle driving state, a steering actuator that drives a steering mechanism, a switching mechanism that switches a steering member and a steering mechanism to a state in which the steering member and the steering mechanism are mechanically disconnected, and a steering actuator; A control device for controlling the steering by controlling and driving the steering mechanism,
When detecting a failure of the steering actuator based on the output of the sensor, the control device drives the switching mechanism to connect the steering member and the steering mechanism, and sets the rotation restricting mechanism to a special state. The vehicle steering apparatus according to claim 1, wherein the vehicle steering apparatus is a vehicle steering apparatus.

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