JP4757507B2 - Vehicle steering system - Google Patents

Description

  The present invention relates to a vehicle steering apparatus capable of mechanically connecting and disconnecting an operator operated by a driver and a turning actuator for turning a steered wheel.

In a so-called steer-by-wire steering device in which the steering wheel (operator) operated by the driver and the steered wheels are not mechanically connected, an appropriate steering reaction force is applied when the driver operates the steering wheel. A reaction force actuator for applying the steering wheel and a steering actuator for turning the steered wheels according to the operation of the driver's steering wheel are provided, and both actuators are controlled independently.
In this steer-by-wire steering device, the steering wheel can be further increased even if the steered wheel reaches the maximum steered position by the steered actuator. It is necessary to recognize that the wheel cannot be steered any more.

As a conventional method for recognizing the maximum steering, a method of preventing the steering wheel from being further increased by suddenly raising the thrust of the reaction actuator when the maximum steering is approached (hereinafter referred to as counter reaction). A method that prevents the steering wheel from being increased beyond the maximum steering by mechanically connecting the steering wheel and the steering actuator when approaching maximum steering. (Hereinafter referred to as a connection type) is known (see, for example, Patent Document 1).
JP 2004-142542 A

  However, in the case of the reaction force rapid increase type, the thrust required for recognizing the maximum steering is larger than the actuator-generated reaction force required during normal steering, and the reaction force is used for maximum steering recognition. It is necessary to increase the output of the actuator, which increases the size of the actuator.

In the case of the connection type, the reaction force actuator can be reduced in size, but when the steering wheel is repeatedly turned and turned back in the vicinity of the maximum turning, the steering wheel and the turning actuator are connected. When the steering reaction force generated by the reaction force actuator and the reaction force transmitted from the tire due to the mechanical connection do not coincide with each other, discontinuous steering reaction force, i.e. A discontinuous response will be given.
Therefore, the present invention provides a vehicle steering apparatus that can easily recognize the maximum turning in the steer-by-wire state.

In order to solve the above-mentioned problem, the invention according to claim 1 includes an operator (for example, a steering wheel 2 in an embodiment described later) operated by a driver and a steered wheel (for example, a wheel 6 in an embodiment described later). A steering actuator (for example, a rack shaft 9 and a steering motor 10 in an embodiment to be described later) and a reaction force actuator (for example, a reaction force motor in an embodiment to be described later) that applies a steering reaction force to the operation element. 4), a steering actuator control means (for example, a steering control unit 20 in an embodiment to be described later) for controlling the steering actuator according to an operation amount to the operation element, and the reaction force actuator are controlled. reaction force actuator control means (e.g., reaction force control unit 23 in the embodiment) equipped with, and, when the steerable wheels is maximized rolling steering If the operation amount is further increased even if the operation element is vibrated by the reaction force actuator and the operation element is vibrated, the return operation of the operation element is started. The operation amount is redefined as the operation amount of the new operation element that generates the maximum turning angle, and the control steering angle between the operation amount of the operation element and the turning angle at the position from the position to the turning angle zero. A vehicle steering apparatus (for example, characterized in that the steering actuator is controlled based on the newly set control steering angle ratio until the operation amount of the operation element becomes zero, by newly setting a ratio. This is a vehicle steering apparatus 1) in an embodiment described later.
With this configuration, the operating element and the steering actuator and the steer-by-wire was mechanically decoupled state, the driver through vibrations of the operator, the steered wheels is the largest rolling steering Can be easily recognized. Further, the thrust of the reaction force actuator necessary for the vibration of the operating element is not significantly different from the thrust required to generate a normal steering reaction force, so that the output and size of the reaction force actuator can be reduced.
Further, even when vibration is applied to the operation element, even when the operation amount to the operation element is further increased, the steered wheels can be set to the neutral position when the operation element is returned to the neutral position.

The invention according to claim 2 is the regulation according to claim 1 in which the operation of the operation element is restricted when the operation amount to the operation element further increases even when vibration is applied to the operation element. Means (for example, a rotation restricting gear 17 and a stopper 19c in an embodiment described later) are provided.
By configuring in this way, it is possible to prevent the operator from over-rotating.

According to the invention of claim 1, the driver by the vibration of the operator, the steered wheels can easily recognize that it is the maximum rolling rudder. Further, since the output of the reaction force actuator can be reduced and the size can be reduced, the output of the vehicle steering device can be reduced and the size can be reduced. Further, even when vibration is applied to the operation element, even when the operation amount to the operation element is further increased, the steered wheels can be set to the neutral position when the operation element is returned to the neutral position.
According to the invention which concerns on Claim 2, the overrotation of an operation element can be prevented.

Embodiments of a vehicle steering apparatus according to the present invention will be described below with reference to the drawings of FIGS.
As shown in FIG. 1, the vehicle steering apparatus 1 includes a steering wheel (operator) 2 that is operated by a driver, a steering shaft 3 that is integrally connected to the steering wheel 2, and a steering wheel 2 that is steered against the steering wheel 2. A rack includes a reaction force motor (reaction force actuator) 4 for applying force, a rack shaft 9 connected to left and right wheels (steered wheels) 6 via a knuckle arm 7 and a tie rod 8, and a pinion gear 10a provided on an output shaft. A steering motor 10 meshed with the rack teeth of the shaft 9 and a control device 5 for controlling the reaction force motor 4 and the steering motor 10 are provided. In this vehicle steering apparatus 1, the wheel 6 can be steered by driving the rack shaft 9 in the axial direction by rotating the steering motor 10. In this embodiment, the rack shaft 9 and the steering motor 10 are turned. A rudder actuator is configured.

The steering shaft 3 is provided with a planetary gear 11 at the tip side thereof, and the planetary gear 11 is engaged with a sun gear 12 and a ring gear 13. A rotation shaft 13 a of the ring gear 13 is provided with a pinion gear 13 b that meshes with the rack teeth of the rack shaft 9. A lock ring 14 is concentrically and integrally connected to the sun gear 12.
The steering shaft 3 is provided with two gears 15 and 16 at its intermediate portion, one gear 15 meshes with a gear 4a attached to the output shaft of the reaction force motor 4, and the other gear 16 is restricted in rotation. The gear 17 is engaged. As shown in FIGS. 2 and 3, the rotation restricting gear 17 has a notch 18 formed by cutting a part of the outer peripheral portion into an arc shape.

In addition, the vehicle steering apparatus 1 includes a clutch 19 that can be engaged with and released from the lock ring 14 and the rotation restriction gear 17. The clutch 19 includes a shaft portion 19b that can rotate around a fulcrum 19a. A stopper 19c that can be inserted into and removed from the notch portion 18 of the rotation restricting gear 17 is provided at one end of the shaft portion 19b. A stopper 19 d that can be engaged and released from the lock ring 14 is provided. The shaft portion 19b is linked to the rod 30a of the electromagnetic solenoid 30, and is rotated following the projecting and retracting operation of the rod 30a.
As shown by a solid line in FIG. 1, when the electromagnetic solenoid 30 is turned on, the rod 30a protrudes and the clutch 19 rotates in the clockwise direction in the drawing. As a result, the stopper 19d is separated from the lock ring 14, and the stopper 19c enters the notch 18 (see FIG. 2). Further, as shown by a broken line in FIG. 1, when the electromagnetic solenoid 30 is turned off, the rod 30a springs back, and the clutch 19 rotates counterclockwise in the drawing. As a result, the stopper 19d engages with the lock ring 14 to make the lock ring 14 non-rotatable, and the stopper 19c retracts from the notch 18 (see FIG. 3). Hereinafter, a state in which the stopper 19d is separated from the lock ring 14 is referred to as a released state of the clutch 19, and a state in which the stopper 19d is engaged with the lock ring 14 and the lock ring 14 cannot be rotated is referred to as an engaged state of the clutch 19. .

In the vehicular steering apparatus 1, when the clutch 19 is released, the lock ring 14 can freely rotate, and the sun gear 12 integrated with the lock ring 14 can also freely rotate. As a result, the planetary gear 11 and the ring gear 13 can rotate without being restricted from each other, and the vehicle steering device 1 becomes a so-called steer-by-wire steering device. At this time, the steering motor 10 and the reaction force motor 4 are independently controlled as will be described later.
Further, in the released state of the clutch 19, the stopper 19c enters the notch 18 of the rotation restricting gear 17, so that the stopper 19c is placed on the end portions 18a and 18b of the notch 18 as shown in FIG. By abutting, rotation of the rotation restricting gear 17 is restricted. That is, when the stopper 19c hits the end portions 18a and 18b of the notch portion 18, the steering wheel 2 becomes the maximum steering angle. Here, the maximum steering angle is set larger than the maximum steering angle of the wheel 6 described later. FIG. 2A shows a state where the steering wheel 2 is neutral.
In this embodiment, the rotation restricting gear 17 and the stopper 19c constitute restricting means for restricting the operation of the operation element (the steering wheel 2).

  On the other hand, when the clutch 19 is engaged, the sun gear 12 integral with the lock ring 14 cannot be rotated, so that the planetary gear 11 and the ring gear 13 rotate at a predetermined rotation ratio. That is, at this time, since the steering wheel 2 and the rack shaft 9 are mechanically connected via the planetary gear 11 and the ring gear 13, the rack shaft 9 can be moved in the axial direction by rotating the steering wheel 2. The wheel 6 can be steered. In other words, at this time, the vehicle steering device 1 is not steer-by-wire, and becomes a steering device capable of manually turning the wheels 6. Then, the rack shaft 9 comes into contact with the stopper (not shown) and the maximum stroke is restricted, and the wheel 6 has the maximum turning angle (maximum turning angle) at that position. Become.

Further, when the clutch 19 is in the engaged state, as shown in FIG. 3, the stopper 19c is retracted from the notch portion 18 of the rotation restricting gear 17, so that the steering wheel 2 is rotated by the stopper 19c and the notch portion 18. Is no longer regulated. In this case, the rotation of the steering wheel 2 is restricted when the wheel 6 is turned to the maximum. 3A shows a state where the steering wheel 2 is neutral, and FIG. 3B shows a state where the maximum steering angle is obtained.
Thus, the clutch 19 can switch the steering wheel 2 (operator) and the rack shaft 9 (steering actuator) between the mechanically connected state and the disconnected state.

  The vehicle steering apparatus 1 includes a steering angle sensor 31 that detects a steering angle (operation amount) of the steering wheel 2, a steering torque sensor 32 that detects steering torque acting on the steering wheel 2, and the axial direction of the rack shaft 9. A turning angle sensor (steering angle detection means) 33 for detecting the turning angle of the wheel 6 from the position, and output signals of these sensors 31 to 33 are input to the electronic control unit 5. An output signal from the vehicle speed sensor 34 that detects the vehicle speed is also input to the electronic control unit 5.

Then, as described above, when the clutch 19 is disengaged and the vehicle steering device 1 is a steer-by-wire steering device, the electronic control device 5 is based on the output signals of these sensors 31-34. The reaction force motor 4 and the steering motor 10 are individually controlled.
Specifically, as shown in the block diagram of FIG. 4, the electronic control unit 5 controls the steering motor 10 based on signals from the steering angle sensor 31, the vehicle speed sensor 34, and the steering angle sensor 33. Unit (steering actuator control means) 20, reaction force control unit (reaction force control unit) that controls the reaction force motor 4 based on signals from the steering control unit 20, the steering torque sensor 32, the vehicle speed sensor 34, and the turning angle sensor 33. Force actuator control means) 23.

The turning control unit 20 sets a target turning angle based on a steering angle signal including the steering direction of the steering wheel 2 from the steering angle sensor 31 and a vehicle speed signal from the vehicle speed sensor 34. Part (target turning angle setting means) 21 and the output value of the turning angle sensor 33, that is, the current supplied to the steering motor 10 for making the actual turning angle of the wheels 6 coincide with the target turning angle. And a steering motor control unit 22 for performing the operation.
Thereby, the optimum turning angle of the wheel 6 is determined in consideration of the vehicle speed at that time with respect to the steering angle (operation amount) given to the steering wheel 2 by the driver.

The reaction force control unit 23 sets a target steering reaction force based on the vehicle speed signal from the vehicle speed sensor 34, the turning angle signal from the turning angle sensor 33, and the steering angle command signal from the turning control unit 20. Steering reaction force setting unit (reaction force determining means) 24 and the target steering reaction force set by the target steering reaction force setting unit 24 are set to match the output value (that is, actual steering torque) of the steering torque sensor 32. And a reaction force motor control unit 25 that controls a supply current to the reaction force motor 4. Here, the steering angle command signal from the turning control unit 20 includes a target turning angle signal output from the target turning angle setting unit 21 and a turning angle signal output from the turning angle sensor 33 (actual turning). Deviation signal).
As a result, a steering reaction force in a direction opposite to the steering direction of the driver is applied to the steering wheel 2, and a steering feeling as if a torsion bar exists between the steering wheel 2 and the wheel 6 is obtained. be able to.

  Further, in this vehicle steering device 1, when the clutch 19 is disengaged and a steer-by-wire steering device is used, the steering wheel 2 is forcibly finely adjusted when the wheel 6 reaches maximum steering. The steering wheel 2 is vibrated so that the driver can recognize the maximum steering, and when the steering wheel 2 is still operated in the direction of increasing the steering angle, the rotation of the steering wheel 2 is prevented to prevent the steering wheel 2 from rotating. To prevent over-rotation.

More specifically with reference to the time chart of FIG. 5, the actual turning angle of the wheel 6 is the maximum turning angle based on the output signal of the turning angle sensor 33 in the reaction force control unit 23 of the electronic control unit 5. Is detected, the target steering reaction force setting unit 24 controls the current supplied to the reaction force motor 4 so as to vibrate the steering wheel 2 at a predetermined minute angle (time t1). The driver can recognize that the wheel 6 is the maximum turning by the warning due to the vibration of the steering wheel 2.
However, as described above, since the maximum steering angle of the steering wheel 2 is set larger than the maximum steering angle of the wheel 6, the clutch 19 is reached when the wheel 6 reaches the maximum steering angle (time t1). The stopper 19c enters the notch 18 of the rotation restricting gear 17, but does not hit the end 18a (or 18b) of the notch 18. Accordingly, the rotation of the steering wheel 2 is not prevented at this time.

  Therefore, the driver may not recognize a warning due to vibration of the steering wheel 2 and may further increase the steering wheel 2 (time t1 to t2). In this case, the steering wheel 2 can be rotated until the stopper 19c hits the end 18a (or 18b) of the notch 18, but the stopper 19c hits the end 18a (or 18b) of the notch 18. Then, the steering wheel 2 cannot be rotated any further. Therefore, even when the driver cannot recognize the warning due to the vibration of the steering wheel 2, the rotation of the steering wheel 2 is prevented, so that the driver can reliably recognize that the wheel 6 is the maximum turning. be able to. Further, since the steering wheel 2 can be prevented from over-rotating, it is possible to prevent the airbag, the electric signal line, and the like built in the steering wheel 2 from being damaged due to the over-rotation.

  In addition, as shown in time t1 to t2 in FIG. 5, when the steering wheel 2 is increased after the warning due to the vibration of the steering wheel 2, the steering angle of the steering wheel 2 is maintained with the wheel 6 fixed at the maximum turning. Therefore, the relationship between the steering angle by the original steer-by-wire function and the control steering angle ratio of the target turning angle (hereinafter referred to as normal control steering angle ratio) is lost. Therefore, when the driver turns back the steering wheel 2 after increasing the steering angle after the warning, the target turning angle is set with the same normal control steering angle ratio as before the warning, and the steering motor 10 is controlled. Then, when the steering wheel 2 is returned to the neutral position, the wheel 6 does not become neutral (the position where the actual turning angle is zero).

  Therefore, in this embodiment, when the steering wheel 2 is switched back after exceeding the operating angle position of the steering wheel 2 that generates the original maximum target turning angle, the operating angle at the position where the switching back operation is started. Is defined as the new steering wheel 2 operating angle that generates the maximum target turning angle, and the position from that position to the actual turning angle zero is reassigned to control the operating angle and the target turning angle. A new steering angle ratio (hereinafter referred to as over-control steering angle ratio) is newly set, and the target turning angle is set based on the over-control steering angle ratio until the operation angle of the steering wheel 2 becomes zero (time t3). The steering motor 10 is controlled. Thereby, when the steering wheel 2 is returned to the neutral position, the wheel 6 can be made neutral (position where the actual turning angle is zero).

  After the operation angle of the steering wheel 2 reaches zero (time t3 to t4), the control rudder angle ratio is returned from the over control rudder angle ratio to the normal control rudder angle ratio, and the normal control rudder angle ratio is obtained. Based on the above, the target turning angle is set, and the steering motor 10 is controlled.

According to the vehicle steering apparatus 1 of this embodiment, the driver by vibrating the steering wheel 2, the wheel 6 can be easily recognized that it is the maximum rolling rudder.
Moreover, the output of the reaction force motor 4 required for vibrating the steering wheel 2 is not significantly different from the output required for generating a normal steering reaction force, so that the reaction force motor 4 is increased in output and size. The output and size of the vehicle steering apparatus 1 can be reduced without necessity.
In addition, since the maximum turning can be recognized while maintaining the steer-by-wire state in which the steering wheel 2 and the rack shaft 9 are not mechanically connected, the steering wheel 2 and the rack shaft 9 are connected to the machine. The discontinuous response due to the discrepancy between the steering reaction force generated by the reaction force motor 4 and the reaction force transmitted from the wheels 6 due to the mechanical connection, as in the case of recognizing the maximum steering by connecting them mechanically. There is no.
Further, when the steering wheel 2 is further increased after the warning due to the vibration of the steering wheel 2, the stopper 19 c hits the end 18 a (or 18 b) of the notch 18, thereby further rotating the steering wheel 2. Since it is blocked, it is possible to prevent the steering wheel 2 from over-rotating and to prevent various problems caused by the over-rotation.

[Other Examples]
The present invention is not limited to the embodiment described above.
For example, in the embodiment described before mentioned, the regulating means for regulating the operation of the operation element, although composed by the rotation restricting gear 17 and the stopper 19c, as long as it has a function of regulating the operation of the operation element, other configurations Can also be adopted.

It is a schematic block diagram in one Example of the vehicle steering device which concerns on this invention. FIG. 5 is a schematic diagram for explaining the operating state of the restricting means when the clutch is disengaged in the vehicle steering device of the embodiment, where (A) is a diagram showing a neutral state of the steering wheel, and (B) is maximum steering. It is a figure which shows the state of a corner. FIG. 6 is a schematic diagram for explaining the operating state of the restricting means when the clutch is engaged in the vehicle steering device of the embodiment, where (A) is a diagram showing a neutral state of the steering wheel, and (B) is the maximum It is a figure which shows the state of a steering angle. It is a control block diagram of the steering apparatus for vehicles of the said Example. It is a figure which shows an example of the time chart in the steering apparatus for vehicles of the said Example.

Explanation of symbols

1 Vehicle steering device 2 Steering wheel (operator)
4 Reaction force motor (Reaction force actuator)
6 wheels (steering wheels)
9 Rack shaft (steering actuator)
10 Steering motor (steering actuator)
17 Rotation restriction gear (regulation means)
19c Stopper 19c (regulating means)
20 Steering control unit (steering actuator control means)
23 reaction force control unit (reaction force actuator control means)

Claims (2)

An operator operated by the driver, and
A steering actuator for steering the steered wheels;
A reaction force actuator for applying a steering reaction force to the operation element;
Steered actuator control means for controlling the steered actuator according to an operation amount to the manipulator;
Reaction force actuator control means for controlling the reaction force actuator;
Wherein the steering wheel to vibrate the operator by the reaction force actuator when it becomes maximum rolling steering and the operation amount of the addition the operating element even when applying vibrations to the operator is increased In this case, the operation amount at the position where the return operation of the operation element is started is redefined as the operation amount of the new operation element that generates the maximum turning angle, and at the position from the position to the zero turning angle. A control steering angle ratio between the operation amount of the operating element and the turning angle is newly set, and the steering actuator is based on the newly set control steering angle ratio until the operation amount of the operating element becomes zero. A vehicle steering apparatus characterized by controlling the vehicle.   A vehicle steering apparatus, comprising: a restricting means for restricting operation of the operation element when an operation amount to the operation element is further increased even when vibration is applied to the operation element.

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