JP2005096767A - Steering device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device of a vehicle capable of quickly switching modes from an automatic steering mode to a normal steering mode according to intentions of a driver without influences of disturbance. <P>SOLUTION: This steering device of a vehicle is constituted in a manner to detect a steering force corresponding value applied to other than a steering force generated by an actuator 50 based on command signals at the time of automatic steering. It is judged that the applied steering forces corresponding to a transmission torque from steering shafts 2, 4 are applied by a driver when change of rotary angles of the steering shafts 2, 4 found in chronological order precedes on the side of a steering wheel H more than on the side of a wheel W, and are applied from the outside of the vehicle when it precedes on the side of the wheel W more than on the side of the steering wheel H. In this steering device, when the steering force is applied by the driver and a value corresponding to the applied steering force is not less than a setting value, the mode can be switched from an automatic steering mode to a normal steering mode for generating the steering force by the driver. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a steering apparatus capable of automatically steering a vehicle.

  In recent years, a command signal is generated by a control device based on a guidance signal sent from a road, a detection signal of a road and surrounding conditions, and a steering device that automatically steers a vehicle by a steering force generated by an actuator based on the command signal. Development is underway.

  In such a steering device, in order to cope with an emergency situation or the like, it is desired that the driver can switch from the automatic steering mode to a normal steering mode in which a steering force is generated.

  Therefore, a means for obtaining a deviation between the command rudder angle corresponding to the command signal to the actuator and the actual rudder angle is provided, and when the deviation is equal to or greater than a set value, it is determined that the driver is against automatic steering, It is considered to switch from the automatic steering mode to the normal steering mode.

  However, when the steering angle is actually changed against the steering force generated by the actuator, a large amount of labor and time are required by the driver. Therefore, there is a problem that it is impossible to deal with an emergency situation promptly.

  In addition to the steering force generated by the actuator during the automatic steering, there is a case where a steering force is applied to the vehicle from the outside based on disturbances such as irregularities and crosswinds on the traveling road. In the conventional configuration, there is a problem that the steering force applied to the vehicle from the outside is erroneously determined as the steering force by the driver, and the automatic steering mode is erroneously switched to the normal steering mode.

  It is an object of the present invention to provide a vehicle steering apparatus that can solve the above-described problems.

  The present invention is applied to a vehicle steering apparatus in which a steering mode can be switched between an automatic steering mode in which an actuator generates a steering force based on a command signal from a control apparatus and a normal steering mode in which a driver generates a steering force. Is done.

The present invention is characterized by means for detecting a value corresponding to a steering force applied in addition to the steering force generated by the actuator during the automatic steering, and whether the additional steering force is applied by the driver or not to the vehicle. And means for switching from the automatic steering mode to the normal steering mode when the additional steering force is added by the driver and the value corresponding to the additional steering force is equal to or greater than a set value. The steering force generated by the driver is transmitted from the steering wheel to the wheel via the steering shaft, and the torque transmitted by the steering shaft based on the additional steering force is obtained as a value corresponding to the additional steering force. The steering wheel side and the wheel side of the steering shaft are elastic according to the torque. Means for obtaining a value corresponding to the rotation angle of the steering shaft on the steering wheel side in a time series, and a value corresponding to the rotation angle on the wheel side of the steering shaft in a time series. And when the change in the rotation angle of the steering shaft on the steering wheel side precedes the change in the rotation angle on the wheel side, it is determined that the additional steering force is applied by the driver, and the steering shaft When the change in the rotation angle on the wheel side precedes the change in the rotation angle on the steering wheel side, it is determined that the additional steering force is applied to the vehicle from the outside.
According to this configuration, it is possible to switch to the normal steering mode without changing the actual steering angle only by the driver adding a steering force during automatic steering. Thereby, it is possible to quickly switch from the automatic steering mode to the normal steering mode in an emergency situation or the like.
Moreover, since it is determined whether the steering force applied during the automatic steering is applied by the driver or externally applied to the vehicle based on disturbances such as unevenness and crosswinds on the traveling road, the vehicle is externally applied. The added steering force can prevent erroneous switching from the automatic steering mode to the normal steering mode.
Further, when a steering force is applied in addition to the steering force generated by the actuator during automatic steering, a value corresponding to the additional steering force can be obtained based on the torque transmitted by the steering shaft. When the change in torque is based on the steering force applied by the driver, the change in the rotation angle of the steering shaft on the steering wheel side precedes the change in the rotation angle on the wheel side. When the change in torque is based on the steering force applied to the vehicle from the outside, the change in the rotation angle on the wheel side of the steering shaft precedes the change in the rotation angle on the steering wheel side. This makes it possible to reliably determine whether the additional steering force is applied by the driver or externally applied to the vehicle.

In the present invention, the actuator is a brushless motor having a rotor that rotates concentrically with the steering shaft, a stator that surrounds the rotor, and a detector for detecting the rotation angle of the rotor, and detecting the rotation angle of the rotor. The value corresponding to the rotation angle on the steering wheel side of the steering shaft is obtained in time series by the device, and the hydraulic actuator for generating the steering assist force and the hydraulic pressure of the pressure oil supplied from the pump to the hydraulic actuator, A control valve for controlling the torque transmitted by the steering shaft is provided on the wheel side of the brushless motor, and the rotation angle of the steering shaft on the wheel side of the control valve is 2 detectors are provided and the second detector detects the steering shaft. A value corresponding to the rotation angle on the wheel side of the steering wheel is obtained in time series, the rotation angle of the steering shaft obtained by the detector of the rotation angle of the rotor, and the rotation angle of the steering shaft obtained by the second detector It is preferable that the torque is obtained from the difference.
According to this configuration, since the rotor of the brushless motor that generates the steering force in the automatic steering mode rotates concentrically with the steering shaft, the structure is compact. In addition, since a value corresponding to a change in the rotation angle of the steering shaft on the steering wheel side can be obtained in a time series by the rotation angle detector of the rotor, a dedicated detector is not necessary. Further, since the torque corresponding to the additional steering force is obtained from the detector of the rotation angle of the rotor and the output of the second detector, a dedicated torque sensor is not required.

In the steering apparatus of the present invention, means for determining whether or not there is a possibility of collision between an obstacle detected in the steering direction by the additional steering force and the vehicle, the additional steering force is added by the driver, and the additional steering is performed. When the value corresponding to the force is greater than or equal to the first set value, the means for switching from the automatic steering mode to the normal steering mode, the additional steering force is added by the driver, and the value corresponding to the additional steering force is There may be provided means for switching from the automatic steering mode to the normal steering mode when it is less than one set value and greater than or equal to the second set value and there is no possibility of collision between the obstacle and the vehicle.
According to this configuration, when the value corresponding to the additional steering force of the driver during automatic steering is equal to or greater than the first set value, even if there is a possibility of collision between the obstacle and the vehicle in the steering direction by the additional steering force, The automatic steering mode is switched to the normal steering mode. This increases the need for steering by the driver during automatic steering, for example when the driver adds a large steering force to avoid obstacles ahead, even if there is another obstacle in the steering direction due to the additional steering force. Even if there is a possibility of collision with an object, it is possible to prevent a major accident or the like by steering the driver and avoiding an obstacle ahead.
Also, if the value corresponding to the driver's additional steering force during the automatic steering is less than the first set value and greater than or equal to the second set value, there is a possibility of collision between the obstacle and the vehicle in the steering direction due to the additional steering force. If not, the automatic steering mode is switched to the normal steering mode. Thus, safety can be ensured when the driver switches to the normal steering mode by applying a steering force during automatic steering.
In this case, the additional steering force is applied by the driver, the value corresponding to the additional steering force is less than the first set value and greater than or equal to the second set value, and the obstacle collides with the vehicle. When possible, a means for switching from the automatic steering mode to the normal steering mode and suppressing the steering of the driver may be provided.
When the value corresponding to the steering force of the driver is less than the first set value and greater than or equal to the second set value, the driver's steering urgency is low. Therefore, if there is a possibility of collision between the obstacle and the vehicle in the steering direction due to the additional steering force, the driver recognizes the presence of the obstacle by switching from the automatic steering mode to the normal steering mode and suppressing the driver's steering. Can be made.

  According to the present invention, in a vehicle steering apparatus capable of selecting an automatic steering mode and a normal steering mode, when an emergency situation occurs in the automatic steering mode, the vehicle can be quickly operated according to the driver's intention without being affected by disturbance. Therefore, it is possible to switch to the normal steering mode and to reduce the cost by making the structure compact and simple.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A rack and pinion type steering device 1 shown in FIG. 1 transmits a steering force generated by a driver from a steering wheel H to a wheel W via a steering shaft. Further, a steering force generated by a brushless motor 50 described later is transmitted to the wheels W via the steering shaft.

  The steering shaft includes an input shaft 2 connected to the steering wheel H and an output shaft 4 connected to the input shaft 2 via a torsion bar 3. The torsion bar 3 is connected to the input shaft 2 via a pin 5 and is connected to the output shaft 4 via a serration 6. A pinion 7 is formed on the output shaft 4, and a wheel W is connected to each end of the rack 8 that meshes with the pinion 7. The input shaft 2 is supported by the motor housing 10 c via a sleeve 2 a and a bearing 9 integrated on the outer periphery, and is supported by the output shaft 4 via a bush 11. The output shaft 4 is supported by the rack housing 10 b via bearings 12 and 13. The rack housing 10b and the motor housing 10c are integrated via a valve housing 10a.

  The input shaft 2 is rotated by a steering torque based on the steering force. The rotation of the input shaft 2 is transmitted to the pinion 7 via the torsion bar 3 and the output shaft 4. The rack 8 moves in the axial direction by the rotation of the pinion 7. The wheels are steered by the movement of the rack 8. At this time, the input shaft 2 on the steering wheel side and the output shaft 4 on the wheel W side of the steering shaft are elastically rotated relative to the coaxial center by the torsion bar 3 being elastically twisted according to the steering torque. To do.

  Oil seals 14 and 15 are provided between the input / output shafts 2 and 4 and the valve housing 10a. A support yoke 16 that supports the rack 8 is provided, and the support yoke 16 is pressed against the rack 8 by the elasticity of the spring 17.

  A hydraulic cylinder (hydraulic actuator) 18 that generates a steering assist force is provided. The hydraulic cylinder 18 includes a cylinder tube constituted by the rack housing 10 b and a piston 20 integrated with the rack 8, and includes a first oil chamber 21 and a second oil chamber 22 partitioned by the piston 20. Have.

  Each of the oil chambers 21 and 22 is connected to a rotary hydraulic control valve 23 that operates based on a steering force, and the hydraulic pressure of the pressure oil supplied from the pump 37 to the hydraulic cylinder 18 is controlled by the control valve 23. Steering assist force is generated.

  That is, the control valve 23 includes a cylindrical first valve member 24 and a second valve member 25 inserted into the first valve member 24 so as to be relatively rotatable coaxially. The first valve member 24 is inserted into the valve housing 10a so as to be relatively rotatable, and is attached to the output shaft 4 via a pin 26 so as to be able to rotate together. The second valve member 25 is integrally formed on the outer periphery of the input shaft 2, and thus rotates together with the input shaft 2. Thereby, the 1st valve member 24 and the 2nd valve member 25 rotate relatively elastically, when the torsion bar 3 twists according to the steering torque transmitted by the said steering shaft. The hydraulic pressure of the pressure oil supplied from the pump 37 to the hydraulic cylinder 18 is controlled according to the relative rotation amount.

  That is, as shown in FIG. 2, a plurality of recesses along the axial direction are formed at equal intervals in the circumferential direction on the inner periphery of the first valve member 24 and the outer periphery of the second valve member 25. The first valve member-side recess is composed of a right steering recess 27 and a left steering recess 28 that are located at equal intervals in the circumferential direction. The concave portion on the second valve member side is composed of a pressure oil supply concave portion 29 and a pressure oil discharge concave portion 30 that are located at equal intervals in the circumferential direction. The right steering recesses 27 and the left steering recesses 28 are alternately arranged in the circumferential direction, and the pressure oil supply recesses 29 and the pressure oil discharge recesses 30 are alternately arranged in the circumferential direction.

  Each of the right steering recesses 27 communicates with the first oil chamber 21 of the hydraulic cylinder 18 from the first flow path 31 formed in the first valve member 24 and the first port 32 formed in the valve housing 10a.

  Each left steering recess 28 communicates with the second oil chamber 22 of the hydraulic cylinder 18 from the second flow path 33 formed in the first valve member 24 and the second port 34 formed in the valve housing 10a.

  Each pressure oil supply recess 29 communicates with the pump 37 via a third flow path 35 formed in the first valve member 24 and an inlet port 36 formed in the valve housing 10a.

  Each pressure oil discharge recess 30 includes a first discharge path 38 formed in the second valve member 25, a passage 47 between the inner and outer periphery of the input shaft 2 and the torsion bar 3, and a discharge port 40 formed in the valve housing 10a. To the tank 41.

  As a result, the oil chambers 21 and 22 of the hydraulic cylinder 18 and the pump 37 are connected via the inter-valve oil passage 42 formed between the inner and outer peripheries of the first valve member 24 and the second valve member 25. . The pump 37 is driven by a motor 64, and can be constituted by, for example, a vane pump or a gear pump that discharges pressure oil at a flow rate corresponding to the rotational speed of the pump driving motor 64. In the inter-valve oil passage 42, between the first valve member side concave portion and the second valve member side concave portion, throttle portions A, B, C, D whose opening degree changes due to relative rotation of both valve members 24, 25, and Is done. The hydraulic pressure acting on the hydraulic cylinder 18 is controlled by changing the opening degree of each throttle part A, B, C, D according to the steering torque. FIG. 3 shows the hydraulic circuit.

  FIG. 2 shows the relative positions of the valve members 24 and 25 in the straight steering position where steering is not performed. In this state, the pressure oil supply recesses 29 and the pressure oil discharge recesses 30 The opening degree of the throttle portions A, B, C, and D is constant.

  When the vehicle is steered to the right from the straight steering position, each right steering recess 27 and each pressure oil supply recess 29 according to the relative amount of rotation of both valve members 24 and 25 due to torsion of the torsion bar 3 according to the steering torque. Between the left steering recess 28 and each pressure oil discharge recess 30, and the left steering recess 28 and each pressure oil supply The opening degree of the throttle part C between the concave part 29 and the opening degree of the throttle part D between each right steering concave part 27 and each pressure oil discharging concave part 30 become small. As a result, pressure oil corresponding to the steering torque is supplied from the pump 37 to the first oil chamber 21, the oil is recirculated from the second oil chamber 22 to the tank 41, and the steering assist force to the right of the vehicle is applied to the rack 8. Works.

  When steering from the straight steering position to the left, the apertures of the throttles A, B, C, and D change in the opposite direction to the steering to the right, so that the steering assist force to the left of the vehicle is applied to the rack 8 Works.

  As shown in FIG. 1, a three-phase brushless motor 50 is provided as an actuator for generating a steering force. The brushless motor 50 includes a rotor 51 attached to the input shaft 2 so as to rotate concentrically with the input shaft 2 via the sleeve 2a, and a stator attached to the motor housing 10c so as to surround the rotor 51. 52 and a detector for detecting the rotation angle of the rotor 51. The detector includes a first resolver 53 having a rotor 53a integrated with the input shaft 2 via a sleeve 2a and a stator 53b attached to the motor housing 10c. The control valve 23 is disposed closer to the wheel W than the brushless motor 50.

  A second resolver 65 that detects the rotation angle of the steering shaft is provided on the wheel W side of the control valve 23. The second resolver 65 has a rotor 65a integrated with the output shaft 4 and a stator 65b attached to the rack housing 10b.

  The coil of the stator 52 of the brushless motor 50 and the stator 53 b of the first resolver 53 are connected to the control device 61. The control device 61 includes a mode changeover switch 62, an input device 63, the pump drive motor 64, a stator 65b of the second resolver 65, and a plurality of obstacle detection sensors 66, 67, 68 attached to the vehicle body. 69 and the vehicle speed sensor 70 are connected.

  By operating the mode switch 62, the vehicle steering mode can be switched between the automatic steering mode and the normal steering mode. In the automatic steering mode, the brushless motor 50 generates a steering force based on a command signal from the control device 61, and in the normal steering mode, the driver generates a steering force.

  For example, a sign signal transmitted from a transmitter provided on a traveling road or a guard rail, an alarm signal for notifying a collision risk transmitted from a transmitter provided in another vehicle, An induction signal such as a travel line detection signal is input. When the guidance signal is input from the input device 63 in the automatic steering mode, the control device 61 and the actual steering angle input from the first resolver 53 and the target steering angle required to steer the vehicle according to the guidance signal. The drive current of the brushless motor 50 is output as a command signal for eliminating the deviation. The steering force generated by the brushless motor 50 is transmitted to the wheels W through the steering shaft, similarly to the steering force generated by the driver in the normal steering mode.

  Further, the control device 61, as the value corresponding to the steering force added in addition to the steering force generated by the brushless motor 50 during the automatic steering, the torque transmitted by the steering shaft based on the additional steering force, It is obtained from the outputs of the first resolver 53 and the second resolver 65.

  That is, the input shaft 2 and the output shaft 4 elastically rotate relative to the coaxial center by the torsion bar 3 being elastically twisted according to the steering torque. Therefore, the difference between the rotation angle of the input shaft 2 detected by the first resolver 53 and the rotation angle of the output shaft 4 detected by the second resolver 65 corresponds to the torque transmitted by the steering shaft.

  FIG. 4 (1) shows the relationship between the output of the first resolver 53 and the rotation angle of the input shaft 2. The control device 61 stores the output Eao of the first resolver 53 when the torque transmitted by the steering shaft is zero and the steering angle is zero as the reference output at the reference position P of the input shaft 2. The control device 61 obtains the rotation angle of the rotor 51 and the rotation angle of the steering shaft on the steering wheel H side in time series from the difference between the actual output of the first resolver 53 and the reference output Eao.

  FIG. 4B shows the relationship between the output of the second resolver 65 and the rotation angle of the output shaft 4. The control device 61 stores the output Ebo of the second resolver 65 when the torque transmitted by the steering shaft is zero and the steering angle is zero as the reference output at the reference position P of the output shaft 4. The control device 61 obtains the rotation angle on the wheel W side of the steering shaft in time series from the difference between the actual output of the second resolver 65 and the reference output Ebo.

  Since the outputs of the resolvers 53 and 65 are sinusoidal waveforms, the rotation angle may be different even if the outputs are the same. Therefore, the reference output Eao of the first resolver 53 is different from the reference output Ebo of the second resolver 65. Thus, by comparing the outputs of the resolvers 53 and 65 with each other, the rotation angle can be obtained accurately, and a dedicated detector for obtaining the reference position is not required, so that the cost can be reduced.

  In order to cope with the case where the rotation angle of the steering shaft exceeds one cycle of the sine waveform of the output of each resolver 53, 65, the control device 61 performs a pulse every one cycle of the sine waveform of the output of each resolver 53, 65. A signal is generated, and for each pulse, the rotation angle of the steering shaft for one cycle of the sine waveform is added to the rotation angle obtained from the difference between the actual output of each resolver 53, 65 and the reference output Ebo.

  The control device 61 obtains the total torque transmitted by the steering shaft from the difference between the rotation angle of the steering shaft obtained by the first resolver 53 and the rotation angle of the steering shaft obtained by the second resolver 65, The torque based on the additional steering force is obtained by subtracting the torque due to the steering force generated by the brushless motor 50 from the total torque transmitted by the steering shaft. Note that the torque due to the steering force generated by the brushless motor 50 can be obtained from the drive current value of the brushless motor 50.

  The control device 61 determines whether the additional steering force is applied by the driver or externally applied to the vehicle. That is, when the change in the rotation angle on the steering wheel H side of the steering shaft precedes the change in the rotation angle on the wheel W side, it is determined that the additional steering force is applied by the driver. On the other hand, when the change in the rotation angle on the wheel W side of the steering shaft precedes the change in the rotation angle on the steering wheel H side, it is determined that the additional steering force is applied to the vehicle from the outside. In the present embodiment, the rotational angular velocity on the steering wheel H side of the steering shaft is compared with the rotational angular velocity on the wheel W side, and it is determined that the rotational angle change precedes the larger rotational angular velocity.

The control device 61 determines whether or not there is a possibility of collision between the obstacle detected in the steering direction by the additional steering force and the vehicle.
In the present embodiment, as shown in FIG. 5, the obstacle detection sensors 66, 67, 68, 69 detect obstacles such as other vehicles and guardrails on the left and right sides and the left and right sides of the vehicle V. Thus, it has a transmitter for emitting radar waves such as laser and ultrasonic waves from the vehicle, a receiver for the radar waves, and an amplifier for the received radar waves. The control device 61 calculates the distance to the obstacle based on the time difference from the transmission to the reception of the radar wave, determines the steering direction of the additional steering force based on the signals from the resolvers 53 and 65, and If an obstacle is detected within a predetermined distance in the steering direction, it is determined that there is a possibility of collision.

  The control device 61 switches from the automatic steering mode to the normal steering mode when the additional steering force is applied by the driver and the value corresponding to the additional steering force is equal to or greater than the first set value. Further, the additional steering force is applied by the driver, the value corresponding to the additional steering force is less than the first set value and greater than or equal to the second set value, and the obstacle and the vehicle can collide. When there is no possibility, the automatic steering mode is switched to the normal steering mode.

The flowchart of FIG. 6 shows a steering mode switching control procedure by the control device 61.
The control device 61 first determines whether or not the current time is in the automatic steering mode (step 1). In the automatic steering mode, automatic steering is performed by driving the brushless motor 50 (step 2).
At the time of the automatic steering, it is determined whether the additional steering force other than the steering force generated by the brushless motor 50 is applied by the driver or a disturbance externally applied to the vehicle (step 3). If the additional steering force is a disturbance, the automatic steering is continued.
When the additional steering force is applied by the driver, it is determined whether the torque T transmitted by the steering shaft is equal to or greater than the first set value T1 based on the additional steering force (step 4).
If the torque T transmitted by the steering shaft is less than the first set value T1, it is determined whether or not it is equal to or greater than the second set value T2 (step 5). If it is less than the second set value T2, automatic steering is continued.
If the torque T transmitted by the steering shaft is less than the first set value T1 and greater than or equal to the second set value T2, it is determined whether there is a possibility of collision with an obstacle (step 6). If there is a possibility of collision with an obstacle, automatic steering is continued.
If the torque T transmitted by the steering shaft based on the additional steering force in step 4 is equal to or greater than the first set value T1, that is, if the driver is acting a large steering force against automatic steering, Since it is considered that the intention of steering is large, automatic steering is canceled by cutting off the drive current of the brushless motor 50 (step 7). If there is no possibility of collision with an obstacle in step 6, the driver's intention of emergency steering is not high, but there is no danger even if the automatic steering is canceled, so the automatic steering is canceled. Alternatively, if the automatic steering mode is not set in step 1, the automatic steering is canceled. When the automatic steering is released, the mode is switched to the normal steering mode.
The first set value T1 can be set based on the steering force generated by the driver when the driver's steering urgency is high. The second set value T2 can be set based on the steering force generated by the driver when the driver indicates the intention to steer.

Further, the control device 61 sets the rotational speed of the pump drive motor 64 to the steering assist speed when the steering assist is necessary, and to the standby speed when the steering assist is not necessary.
That is, if the steering torque is equal to or greater than the set value, the control device 61 outputs an instruction signal for setting the rotational speed of the pump drive motor 64 to the steering assist speed. The steering assist speed is a speed set in advance so that the flow rate of the pressure oil sent from the pump 37 becomes a flow rate necessary for steering assist. The steering assist speed changes according to the vehicle speed detected by the vehicle speed sensor 70. That is, the steering assist speed is determined so that the steering assist force is increased at low vehicle speeds to improve the turning performance of the vehicle, and the steering assist force is decreased at high vehicle speeds to improve the running stability of the vehicle. As a result, a steering assist force is generated in both the normal steering mode and the automatic steering mode.
If the value of the steering torque is less than the set value, the control device 61 outputs an instruction signal for setting the rotational speed of the pump drive motor 64 to the standby speed. The standby speed is a preset speed smaller than the steering assist speed, and is zero in the present embodiment, but may be a value larger than zero. Thereby, energy saving can be achieved.

According to the above configuration, the driver can switch to the normal steering mode without changing the actual steering angle only by applying a steering force during automatic steering. Thereby, it is possible to quickly switch from the automatic steering mode to the normal steering mode in an emergency situation or the like. In addition, since it is determined whether the steering force applied during the automatic steering is applied by the driver or externally applied to the vehicle, it is possible to erroneously switch from the automatic steering mode to the normal steering mode due to disturbance. Can be prevented.
Further, when the value T corresponding to the additional steering force of the driver during the automatic steering is equal to or greater than the first set value T1, the vehicle V automatically collides even if there is a possibility of collision between the obstacle and the vehicle V in the steering direction by the additional steering force. The steering mode is switched to the normal steering mode. This increases the need for steering by the driver during automatic steering, for example when the driver adds a large steering force to avoid obstacles ahead, even if there is another obstacle in the steering direction due to the additional steering force. Even if there is a possibility of collision with an object, it is possible to prevent a major accident or the like by steering the driver and avoiding an obstacle ahead. In addition, when the value T corresponding to the additional steering force of the driver during the automatic steering is less than the first setting value T1 and equal to or more than the second setting value T2, the obstacle and the vehicle in the steering direction by the additional steering force. If there is no possibility of collision, the automatic steering mode is switched to the normal steering mode. Thus, safety can be ensured when the driver switches to the normal steering mode by applying a steering force during automatic steering.
During the automatic steering, which additional steering force other than the steering force generated by the brushless motor 50 is preceded by the change in the rotation angle on the steering wheel H side of the steering shaft or the change in the rotation angle on the wheel W side Based on the above, it is possible to reliably determine whether it is added by the driver or added to the vehicle from the outside.
Since the rotor 51 of the brushless motor 50 that generates a steering force in the automatic steering mode rotates concentrically with the steering shaft, the response to the control by the control device 61 is quick, and the structure becomes compact and simple. In addition, since the first resolver 53 of the brushless motor 50 can obtain the value corresponding to the change in the rotation angle of the steering shaft on the steering wheel H side in time series, a dedicated detector is not required. Further, since the torque corresponding to the additional steering force is obtained from the outputs of the first resolver 53 and the second resolver 65, a dedicated torque sensor becomes unnecessary. Thereby, the structure can be made simple and compact, and the manufacturing cost can be reduced. In addition, the output of the resolvers 53 and 65 can be adjusted simply by rotating the rotors 53a and 65a with respect to the stators 53b and 65b.

  FIG. 7 shows a flowchart of a first modification of the present invention. The difference from the flowchart of the above embodiment is that when the torque T transmitted by the steering shaft based on the additional steering force of the driver is less than the first set value T1 and greater than or equal to the second set value T2, it collides with an obstacle. If there is a possibility, the automatic steering is canceled and the mode is switched to the normal steering mode (step 8). Then, the steering is suppressed (step 9), and the steering suppression is continued until the possibility of collision disappears. In this case, the steering suppression can be performed by applying a steering force in a direction opposite to the steering direction due to the additional steering force by the driver or reducing the rotational speed of the pump driving motor 64 by the brushless motor 50. Others are the same as that of the said embodiment. When the value T corresponding to the steering force of the driver is less than the first set value T1 and greater than or equal to the second set value T2, the driver's steering urgency is low. Therefore, if there is a possibility of collision between the obstacle and the vehicle in the steering direction due to the additional steering force, the driver recognizes the presence of the obstacle by switching from the automatic steering mode to the normal steering mode and suppressing the driver's steering. Can be made.

  8 and 9 show a second modification of the present invention. The difference from the above embodiment is that a torque sensor 107 is provided between the brushless motor 50 and the control valve 23 instead of the second resolver 65.

The torque sensor 107 is connected to the first and second detection coils 133 and 134 held by the valve housing 10a and the first valve member 24 of the control valve 23 via a connecting member 140 so as to be able to rotate together. A first detection ring 136 made of a magnetic material and a second detection ring 137 made of a magnetic material connected to the input shaft 2 so as to be able to rotate together.
The one end surface of the first detection ring 136 and the one end surface of the second detection ring 137 are arranged so as to face each other, and teeth 136a and 137a are respectively provided on the opposing end surfaces of the detection rings 136 and 137 along the circumferential direction. A plurality are provided.
The other end side of the second detection ring 137 is a small-diameter portion 137b having a smaller outer diameter than the one end side.
The first detection coil 133 is disposed so as to cover the space between the first detection ring 136 and the second detection ring 137, and the second detection coil 134 is disposed so as to cover the second detection ring 137. , 134 are connected to a signal processing circuit 141 formed on a substrate attached to the valve housing 10a. In the signal processing circuit 141, the first detection coil 133 is connected to the oscillator 146 via the resistor 145, the second detection coil 134 is connected to the oscillator 146 via the resistor 147, and each detection coil 133, 134 is differentially connected. The amplifier circuit 148 is connected.
As a result, when the torsion bar 3 is twisted by the torque transmitted by the steering shaft and the two detection rings 136 and 137 rotate relative to each other elastically, the opposing areas of the teeth 136a and 137a of the detection rings 136 and 137 change. Due to the change in area, the magnetic resistance to the magnetic flux generated by the first detection coil 133 between the teeth 136a and 137a changes. Therefore, the output of the first detection coil 133 changes according to the change, and corresponds to the output. The transmitted torque is detected. The torque detection signal is input to the control device 61.
The second detection coil 134 faces the small diameter portion 137 b of the second detection ring 137. The outer diameter of the small-diameter portion 137b is set so that the magnetic resistance with respect to the magnetic flux generated by the second detection coil 134 and the magnetic resistance with respect to the magnetic flux generated by the first detection coil 133 are equal in a state where the steering resistance is not acting. ing. As a result, the output fluctuation of the first detection coil 133 due to the temperature fluctuation is equal to the output fluctuation of the second detection coil 134 due to the temperature fluctuation, so that it is canceled out by the differential amplifier circuit 148, and the fluctuation of the detected value of the steering torque due to the temperature Compensated.
Further, in place of the oil seal 14 between the input shaft 2 and the valve housing 10a in the above embodiment, the oil seal 114 is provided between the connecting member 140 and the input shaft 2, and between the connecting member 140 and the valve housing 10a. Is placed.
Others are the same as in the above embodiment, and the same parts are denoted by the same reference numerals.

According to the second modification, torque transmitted by the steering shaft is obtained by the torque sensor 107 as a value corresponding to the steering force applied in addition to the steering force generated by the brushless motor 50 during automatic steering. The torque detected by the torque sensor 107 corresponds to the rotation angle on the wheel W side of the steering shaft. The control device 61 obtains the torque detected by the torque sensor 107 in time series. When the change in the rotation angle on the steering wheel H side of the steering shaft required by the first resolver 53 precedes the change in torque detected by the torque sensor 107, the control device 61 adds the additional steering force by the driver. Judge that it was done. On the other hand, when the change in torque detected by the torque sensor 107 precedes the change in the rotation angle on the steering wheel H side, it is determined that the additional steering force is applied to the vehicle from the outside.
In the second modification, the control valve 23 and the torque sensor 107 share the torsion bar 3, so that a reduction in rigidity of the torsion bar 3 can be prevented.

  FIG. 10 shows a third modification of the present invention. The difference from the second modification is that a brushed motor 150 is used instead of the brushless motor 50, and the rotation of the motor 150 is transmitted to the input shaft 2 via the electromagnetic clutch 151 and the speed reduction mechanism 152. Further, instead of the first resolver 53, a steering angle sensor 153 is provided between the steering wheel H and the speed reduction mechanism 152. In this case, the automatic steering mode is released by interrupting rotation transmission by the electromagnetic clutch 151 or by interrupting rotation transmission by the electromagnetic clutch 151 and stopping driving of the motor 150. Further, the rotation angle of the steering shaft on the steering wheel H side is obtained in time series based on the output of the steering angle sensor 153. Others are the same as those of the second modification.

  FIG. 11 shows a fourth modification of the present invention. The difference from the second modification is that the steering assist force is applied using an electric actuator instead of the hydraulic actuator. That is, the output of the motor 160 is applied to the output shaft 4 via the electromagnetic clutch 161 and the speed reduction mechanism 162 based on the signal from the control device 61 so that a steering assist force corresponding to the torque detected by the torque sensor 107 can be applied. introduce. Others are the same as those of the second modification.

In addition, this invention is not limited to the said embodiment and modification.
For example, the value corresponding to the additional steering force is the torque transmitted by the steering shaft based on the additional steering force in the above embodiment, but is not particularly limited. For example, the torque change acceleration or the torque It is good also as a time integral value of.
A torque sensor that detects torque transmitted by the steering shaft may be provided between the steering wheel and the steering force generating actuator. In this case, the torque transmitted by the steering shaft based on the additional steering force can be directly obtained without subtracting the torque generated by the actuator from the total torque transmitted by the steering shaft as described above.

Sectional drawing of the steering device of the vehicle of embodiment of this invention II-II sectional view of FIG. 1 is a hydraulic circuit diagram of a vehicle steering apparatus according to an embodiment of the present invention; FIG. 4A is a diagram showing the relationship of the output of the first resolver and FIG. 2B is the diagram showing the relationship of the output of the second resolver with respect to the rotation angle of the steering shaft of the steering apparatus for a vehicle according to the embodiment of the present invention. Plan view for explaining the arrangement of an obstacle detection sensor for a vehicle according to an embodiment of the present invention The flowchart which shows the control procedure of the steering device of the vehicle of embodiment of this invention. The flowchart which shows the control procedure of the steering device of the vehicle of the 1st modification of this invention. Sectional drawing of the steering apparatus of the vehicle of the 2nd modification of this invention Output processing circuit diagram of torque sensor of vehicle steering device of second modified example of the present invention Sectional drawing of the steering apparatus of the vehicle of the 3rd modification of this invention Structure explanatory drawing of the steering device of vehicles of the 4th modification of the present invention

Explanation of symbols

2 Input shaft 4 Output shaft 18 Hydraulic cylinder 23 Control valve 50 Brushless motor 51 Rotor 52 Stator 53 First resolver 61 Controller 65 Second resolver 107 Torque sensor 150 Motor 153 Steering angle sensor 160 Motor H Steering wheel V Vehicle W Wheel

Claims (2)

In a vehicle steering device capable of switching a steering mode between an automatic steering mode in which an actuator generates a steering force based on a command signal from a control device and a normal steering mode in which a driver generates a steering force,
Means for detecting a value corresponding to a steering force applied in addition to the steering force generated by the actuator during the automatic steering;
Means for determining whether the additional steering force is applied by the driver or externally to the vehicle;
Means for switching from the automatic steering mode to the normal steering mode when the additional steering force is applied by the driver and the value corresponding to the additional steering force is greater than or equal to the set value, the steering force generated by the driver is Transmitted from the steering wheel to the wheel via the steering shaft,
As a value corresponding to the additional steering force, a torque transmitted by the steering shaft based on the additional steering force is obtained,
The steering wheel side and the wheel side of the steering shaft are elastically rotatable relative to the torque,
Means for obtaining a value corresponding to the rotation angle of the steering shaft on the steering wheel side in time series;
Means for obtaining a value corresponding to the rotation angle on the wheel side of the steering shaft in time series,
When the change of the rotation angle on the steering wheel side of the steering shaft precedes the change of the rotation angle on the wheel side, it is determined that the additional steering force is applied by the driver, and the rotation of the steering shaft on the wheel side is determined. A steering apparatus for a vehicle, wherein when the change in angle precedes the change in the rotation angle on the steering wheel side, it is determined that the additional steering force is applied to the vehicle from the outside. The actuator is a brushless motor having a rotor that rotates concentrically with the steering shaft, a stator that surrounds the rotor, and a detector for the rotation angle of the rotor,
A value corresponding to the rotation angle of the steering shaft on the steering wheel side is obtained in a time series by the rotation angle detector of the rotor,
A hydraulic actuator for generating a steering assist force and a control valve for controlling the hydraulic pressure of the pressure oil supplied from the pump to the hydraulic actuator according to the torque transmitted by the steering shaft are provided. Located on the wheel side of the brushless motor,
A second detector for the rotation angle of the steering shaft on the wheel side of the control valve is provided;
A value corresponding to the rotation angle on the wheel side of the steering shaft is obtained in time series by the second detector,
2. The vehicle steering according to claim 1, wherein the torque is obtained from a difference between a rotation angle of a steering shaft obtained by a detector of the rotation angle of the rotor and a rotation angle of the steering shaft obtained by the second detector. apparatus.

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