JP7211314B2 - vehicle controller - Google Patents

Description

The disclosure described herein relates to a vehicle control device applied to a vehicle having a parking lock device.

Patent Document 1 describes a parking lock device that locks driving wheels of a vehicle. This parking lock device has a lock gear, an engagement piece and an actuator.

When the engaging piece is locked by the actuator, the engaging piece engages with the lock gear. The lock gear rotates together with the drive wheels, and the engagement locks the rotation of the drive wheels together with the lock gear. When the actuator releases the engagement piece, the engagement piece disengages from the lock gear and is disengaged, thereby unlocking the rotation of the driving wheel.

Japanese Patent Application Laid-Open No. 2008-151308

Now, when the parking lock device is operated to lock on a slope, the engaging piece is pressed against the lock gear so that the vehicle does not slide down the slope, and the locking function is exhibited. However, if the load applied in this manner is excessive, even if the actuator is operated to unlock, the engaging piece will not come off the lock gear and will remain engaged, which may result in unlocking failure.

Therefore, an object of the disclosure described in this specification is to provide a vehicle control device that improves the certainty of unlocking the parking lock device.

One of the disclosures is
A lock gear (41) that rotates together with the wheels (11L, 11R), an engagement member (42, 42A, 42B) that engages with the lock gear to lock the rotation of the wheels, and an actuator (44) that operates to release the engagement. ), a parking lock device (40) having
A vehicle control device applied to a vehicle (10) comprising a steering drive device (20) that exerts a force to steer wheels,
a determination unit (S10) that determines whether or not there is an unlock request for the parking lock device;
A steering control unit (S60) that operates the steering drive device so as to steer in a direction that reduces the pressing load (F2) that the lock gear presses against the engaging member when the determination unit determines that there is an unlock request. )When,
A vehicle control device comprising:

Now, in a general vehicle, when the wheels are deflected by the steering drive device, the center of rotation of the deflection operation is different from the ground contact center of the wheels. Therefore, even if the vehicle is steered (that is, deflected) while the vehicle is stopped, the wheels will rotate slightly. As a result, the lock gear also rotates slightly. Then, even if the load that the engaging member presses against the lock gear is excessive, the load will be reduced if the lock gear rotates in the direction opposite to the pressing direction.

Focusing on this point, the vehicle control device steers the vehicle in a direction to reduce the load when there is a request for unlocking. Therefore, it is possible to suppress the failure of unlocking due to the excessive load, and improve the certainty of unlocking.

It should be noted that the reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments described later, and do not limit the technical scope in any way.

1 is a schematic diagram showing a vehicle control device according to a first embodiment and a vehicle to which the control device is applied; FIG. FIG. 4 is a cross-sectional view schematically showing a state in which the traveling drive device is attached to the drive shaft; FIG. 4 is a cross-sectional view schematically showing a released state of the parking lock device; 4 is a cross-sectional view taken along line IV-IV of FIG. 3; FIG. It is a figure which shows the change from the release state to an engagement state of a parking lock device. FIG. 10 is a diagram showing case 1 of failure to unlock the parking lock device; FIG. 10 is a diagram showing case 2 of failure to unlock the parking lock device; FIG. 5 is a diagram showing how the ground contact center of the steered wheels moves along with steering in the first embodiment. FIG. 4 is a diagram showing the relationship between the direction in which the contact center of the steered wheels moves and the direction of rotation of the traveling drive device in the first embodiment; 4 is a flowchart showing a control procedure executed by the vehicle control device according to the first embodiment; 9 is a flowchart showing a control procedure executed by a vehicle control device according to a second embodiment; FIG. 10 is a flowchart showing a control procedure executed by a vehicle control device according to a third embodiment; FIG. FIG. 11 is a diagram showing the relationship between the direction in which the ground contact center of the steered wheels moves and the rotation direction of the traveling drive device in the third embodiment. FIG. 11 is a flowchart showing a control procedure executed by a vehicle control device according to a fourth embodiment; FIG. FIG. 11 is a flowchart showing a control procedure executed by a vehicle control device according to a fifth embodiment; FIG. FIG. 18 is a view taken along arrow XVI in FIG. 17, showing the structure of the parking lock device according to the sixth embodiment; FIG. 11 is a cross-sectional view schematically showing the structure of a parking lock device according to a sixth embodiment; FIG. 20 is a view taken along line XVIII in FIG. 19, showing the structure of the parking lock device according to the seventh embodiment; FIG. 11 is a cross-sectional view schematically showing the structure of a parking lock device according to a seventh embodiment; FIG. 11 is a cross-sectional view schematically showing the arrangement of a parking lock device according to an eighth embodiment;

A plurality of embodiments of the present disclosure will be described below based on the drawings. Note that redundant description may be omitted by assigning the same reference numerals to corresponding components in each embodiment. When only a part of the configuration is described in each embodiment, the configurations of other embodiments previously described can be applied to other portions of the configuration.

(First embodiment)
A vehicle 10 shown in FIG. 1 includes a steering drive device 20, a travel drive device 30, a parking lock device 40, and a vehicle control device. The vehicle control device is also called an ECU 50 . ECU is an abbreviation for electronic control unit and means an electronic control unit. Of the wheels of the vehicle 10, the wheels steered by the steering drive device 20 are referred to as steered wheels in the following description. Moreover, in this embodiment, the tire attached to the wheel corresponds to a wheel. Of the steered wheels 11, the steered wheel positioned on the left side of the vehicle is also referred to as the left steered wheel 11L, and the steered wheel positioned on the right side of the vehicle is also referred to as the right steered wheel 11R.

The steering driving device 20 exerts a steering driving force for steering the left and right steered wheels 11 . The steering drive device 20 is connected to the tie rod 13 . A tie rod 13 is connected to the arm 14 . Arm 14 is connected to drive shaft 12 . Drive shaft 12 is connected to hub 15 . The drive shaft 12 is divided into a plurality of parts, and each part is connected by a joint 12a such as a constant velocity joint.

A steering drive force exerted by the steering drive device 20 causes the tie rod 13 to move in the lateral direction of the vehicle 10 . Then, the arm 14 rotates around the rotation shaft 16, and the drive shaft 12 and the hub 15 rotate together with the arm 14. As shown in FIG. As a result, the steered wheels 11 are deflected and steered.

The steering drive 20 has an electric motor 21 . The operation of the electric motor 21 is controlled by the ECU 50 . When the driver of the vehicle 10 operates the steering wheel, the electric motor 21 is controlled so that the steering angle of the steered wheels 11 corresponds to the operating position. The steering drive device 20 simultaneously deflects both the left and right steered wheels 11 with a single electric motor 21 . In other words, the steering drive device 20 has a structure in which the left steered wheel 11L and the right steered wheel 11R are interlocked to deflect, and the steered angle of the left steered wheel 11L and the right steered wheel 11R are the same.

The traveling drive device 30 exerts a traveling driving force for causing the vehicle 10 to travel. The running driving force is transmitted to the front wheels of the front and rear wheels provided in the vehicle 10, that is, the steered wheels 11. As shown in FIG. Further, the traveling drive device 30 can also be driven to rotate by the rotational force of the drive shaft 12 that rotates together with the steered wheels 11 to generate regenerative power. The vehicle 10 applied to the present embodiment is a four-wheeled vehicle having two front and rear wheels, and has a structure in which driving force is transmitted to the front steered wheels 11 .

The traveling drive device 30 is provided for each of the left steered wheel 11L and the right steered wheel 11R. Therefore, the running driving force transmitted to the left steered wheel 11L and the running driving force transmitted to the right steered wheel 11R can be independently controlled. It is also possible to control the direction of rotation of the driving force to be reversed between the left steered wheel 11L and the right steered wheel 11R. For example, it is possible to control transmission of a forward driving force to one steered wheel 11 and a reverse driving force to the other steered wheel 11 at the same time.

As shown in FIG. 2 , the traveling drive device 30 has an inverter 31 , an electric motor 32 and a speed reducer 33 . The inverter 31, the electric motor 32 and the reduction gear 33 are integrally assembled and attached to the vehicle body as one unit.

The inverter 31 converts the DC power of the vehicle-mounted battery into AC power and supplies the AC power to the electric motor 32 . Inverter 31 has three-phase upper and lower arm circuits, capacitors, and the like. The upper and lower arm circuits have two switching elements connected in series. AC power output from the midpoint of these two switching elements is output to the electric motor 32 . The operation of the switching elements is controlled by the ECU 50 . In other words, the ECU 50 controls the forward rotation driving force or the reverse rotation driving force exerted by the electric motor 32 by controlling the operation of the switching element according to the required travel driving force.

The electric motor 32 has a fixed core 32a, a rotor 32b and a motor shaft 32c. The fixed core 32a has a winding through which an alternating current supplied from the inverter 31 flows. The rotor 32b has a plurality of permanent magnets evenly spaced around the axis of rotation. The rotor 32b rotates in response to changes in the magnetic field generated by the stationary core 32a. The motor shaft 32c rotates together with the rotor 32b.

The speed reducer 33 has an input gear 33a, a first counter gear 33b, a second counter gear 33c, a drive gear 33d and a counter shaft 33e. The input gear 33a is fixed to the motor shaft 32c and rotates at the same rotational angular velocity as the motor shaft 32c.

The first counter gear 33b meshes with the input gear 33a and rotates at a lower speed than the input gear 33a. The first counter gear 33b and the second counter gear 33c are fixed to the counter shaft 33e. Therefore, the second counter gear 33c rotates at the same rotational angular velocity as the first counter gear 33b.

The drive gear 33d meshes with the second counter gear 33c and rotates at a lower speed than the second counter gear 33c. The drive gear 33 d is fixed to the drive shaft 12 . Therefore, the drive shaft 12 rotates at the same rotational angular velocity as the drive gear 33d.

With the above configuration, the speed reducer 33 reduces the rotational speed when transmitting the driving force exerted by the electric motor 32 to the drive shaft 12 . Further, as described above, the traveling drive device 30 is provided for each of the left and right steered wheels 11 . Therefore, the traveling drive device 30 does not require a differential gear for distributing the traveling driving force to the left and right steered wheels 11, and has a structure in which the drive gear 33d is fixed to the drive shaft 12 as described above. Therefore, when the steered wheels 11 rotate, the rotational force is transmitted to the speed reducer 33 through the drive shaft 12 .

The parking lock device 40 is a device that locks the rotation of the steered wheels 11 . A parking lock device 40 is provided for each of the 30 steering wheels 11 on the left and right. As shown in FIGS. 3 and 4, the parking lock device 40 has a lock gear 41, an engagement member 42, a power transmission section 43, an actuator 44, a release spring 45 and a locking member 46. As shown in FIG.

The lock gear 41 is fixed to the countershaft 33e and rotates at the same rotational angular velocity as the countershaft 33e.

The engaging member 42 has an engaging portion 421 , a pressing portion 422 and a rotating shaft 423 . The engagement member 42 is held so as to be rotatable around the rotation shaft 423 . When it rotates to one side (engagement operation), the engaging portion 421 engages with the gear portion 411 of the lock gear 41 . When it rotates to the other side (release operation), the engaging portion 421 is disengaged from the gear portion 411 and the engagement is released. When the engaging portion 421 is engaged with the gear portion 411, the lock gear 41 and the counter shaft 33e are locked from rotating. As a result, the rotation of the drive shaft 12 is locked, and thus the rotation of the steered wheels 11 is locked.

The releasing spring 45 applies elastic force to the engaging member 42 in a direction in which the engaging member 42 is released. A torsion coil spring is used for the release spring 45 . One end of the torsion coil spring is engaged with the engaging member 46 and the other end is engaged with the engaging member 42 . When the engaging member 42 engages, the deformation amount of the releasing spring 45 increases, and the elastic force for releasing the engagement increases.

The power transmission section 43 has a shaft 431 , a tube 432 , a rod 433 , an engagement spring 434 , a driving section 435 and a locking ring 436 . The shaft 431 is inserted into the through hole of the tube 432 . The shaft 431 is fixed to a case that houses the speed reducer 33 .

The tube 432 is inserted into the through hole of the rod 433 . The tube 432 is attached to the shaft 431 so as to be able to reciprocate with respect to the shaft 431 . A driving portion 435 is attached to one end of the tube 432 . The driving part 435 is fixed to the tube 432 and reciprocates with the tube 432 .

The rod 433 is attached to the tube 432 so as to be able to reciprocate with respect to the tube 432 . Rod 433 has a small diameter portion D1, a tapered portion D2 and a large diameter portion D3. The small diameter portion D1, the tapered portion D2 and the large diameter portion D3 come into contact with the pressing portion 422 of the engaging member . An engagement spring 434 is arranged between the large diameter portion D3 and the driving portion 435 .

A coil spring is used for the engagement spring 434 . The amount of deformation of the engaging spring 434 increases as the distance between the large diameter portion D3 and the driving portion 435 decreases, and the elastic force increases. This elastic force is applied to the rod 433 toward the side where the rod 433 moves toward the engaging portion 421 (leftward in FIG. 3). The leftward operation corresponds to the engaging operation, and the rightward operation corresponds to the releasing operation.

A locking ring 436 is attached to one end of the tube 432 . The locking ring 436 limits the range of reciprocating movement of the rod 433 . That is, the locking ring 436 functions as a retainer so that the rod 433 does not come off from the tube 432 . Although not shown, a similar locking ring may be attached to shaft 431 to prevent tube 432 from coming off shaft 431 .

The actuator 44 (see FIG. 2) is connected to the driving portion 435 and causes the driving portion 435 to reciprocate. The operation of actuator 44 is controlled by ECU 50 . In other words, the ECU 50 controls the engagement operation and disengagement operation of the drive unit 435 by controlling the operation of the actuator 44 .

FIG. 5 shows a change from the disengaged state to the engaged state, and the engagement and disengagement operations of the parking lock device 40 will be described below with reference to FIG.

When the driving portion 435 starts engaging operation in the released state where the small diameter portion D1 is in contact with the pressing portion 422, the rod 433 starts engaging operation while the elastic force of the engaging spring 434 increases. Accordingly, the rod 433 slides against the pressing portion 422, and the contact portion of the rod 433 with the pressing portion 422 transitions from the small diameter portion D1 to the tapered portion D2 (see the middle part of FIG. 5). As a result, the engaging member 42 is pushed by the rod 433 to start the engaging operation.

After that, the elastic force of the engaging spring 434 further increases, and when it becomes larger than the sum of the elastic force of the releasing spring 45 and the sliding resistance, the rod 433 slides further. Then, the contact portion of the rod 433 with the pressing portion 422 transitions from the tapered portion D2 to the large-diameter portion D3 (see the lower part of FIG. 5). As a result, the engaging member 42 is pushed by the rod 433 and moves to a position where it engages with the gear portion 411 of the lock gear 41 . As a result, the engaging portion 421 is engaged with the gear portion 411, and the steered wheels 11 are locked in rotation.

In addition, as shown in the lower part of FIG. 5, the sliding resistance force is smaller in the state in which the engagement is completed than in the state in the middle of the engagement. Therefore, the elastic force of the engaging spring 434 required to maintain the engaged state is smaller than the elastic force of the engaging spring 434 during the engagement.

When the drive portion 435 is moved in the release direction by the actuator, the contact portion of the rod 433 with the pressing portion 422 transitions from the large diameter portion D3 to the tapered portion D2 (see the middle part of FIG. 5). As a result, the engagement member 42 is pushed by the elastic force of the release spring 45 to start the release operation.

After that, the rod 433 slides further. Along with this, the disengagement operation of the engaging member 42 progresses, and the engaging portion 421 is disengaged from the gear portion 411 (see the upper part of FIG. 5). That is, the rotation lock of the steered wheels 11 is released.

In some cases, even if the actuator 44 is operated in a direction to release the driving portion 435, the engaging member 42 does not release and the rotation lock of the steered wheels 11 is not released. Two cases in which such release failure occurs will be described below with reference to FIGS. 6 and 7. FIG.

When the rotation lock by the parking lock device 40 is performed on a slope, the engaging portion 421 is pressed against the gear portion 411 so that the vehicle does not slide down the slope, thereby exhibiting a locking function.

However, when the slope is large and the load of the vehicle 10 is large, the force (rotational force F1) that causes the lock gear 41 to rotate together with the countershaft 33e becomes large. Then, the force (pressing load F2) with which the engaging portion 421 is pressed against the gear portion 411 increases. As a result, even if the actuator 44 is operated to release the lock (disengagement), the engaging member 42 remains engaged with the lock gear 41 without being disengaged, and there is a risk that the release will fail.

For example, in the release failure case 1 shown in FIG. However, the frictional force generated between the engaging portion 421 and the gear portion 411 is increased by the pressing load F2, and is greater than the elastic force of the release spring 45. FIG. Therefore, even though the rod 433 is released, the engagement member 42 remains engaged with the lock gear 41 and is not unlocked.

Further, for example, in the release failure case 2 shown in FIG. 7, the contact surface between the engaging portion 421 and the gear portion 411 has a tapered shape. Due to this, when the pressing load F2 acts on the engaging member 42, a force (vertical pressing load F3) that presses the engaging member 42 against the rod 433 acts. Then, the frictional force generated between the pressing portion 422 and the rod 433 is increased by the vertical pressing load F3. As a result, even if the drive unit 435 tries to release the actuator 44, the rod 433 cannot be released against the frictional force, and the lock is not released.

As a countermeasure against these unlocking failures, the ECU 50 operates the steering drive device 20 when there is a lock unlocking request for the parking lock device 40 . According to this, the pressing load F2 can be reduced (the load is removed) by the principle shown in FIG. 8, which will be described below, and unlocking can be promoted.

The upper part of FIG. 8 shows a state in which the vehicle is steered in a straight running direction, and the steering angle in this state is assumed to be zero. The lower part of FIG. 8 shows a state in which the vehicle is steered in a right-turning direction (right-turning steering), where the steering angle toward the right-turning steering side is positive, and the steering angle toward the left-turning steering side is negative.

As shown in FIG. 8, the pivotal center of the deflection operation by steering is the pivotal center of the arm 14, that is, the axial center of the rotary shaft 16, which is offset from the ground contact centers P1 and P2 of the steered wheels 11. As shown in FIG. Therefore, the ground contact center P1 when the steering angle is zero shown in the upper part of FIG. 8 is different from the ground contact center P2 when the steering angle is positive shown in the lower part. Therefore, even if the vehicle is steered (that is, deflected) while the vehicle is stopped, the steered wheels 11 will rotate slightly.

The rotation of the steered wheels 11 means that the countershaft 33e rotates together with the drive shaft 12, and the lock gear 41 rotates together with the countershaft 33e. Then, if the direction of rotation is opposite to the pressing load F2 shown in FIGS. 6 and 7, the pressing load F2 is reduced or eliminated. Focusing on this point, the ECU 50 steers the vehicle in a direction to reduce the pressing load F2 when there is an unlocking request, thereby recovering from the unsuccessful state of unlocking.

When the drive shaft 12 is slightly rotated by steering when the vehicle is stopped as described above, the motor shaft 32c is also slightly rotated in conjunction with the drive shaft 12. As shown in FIG. In this case, if the electric motor 32 is kept de-energized, a drag torque is generated in the electric motor 32 . As a result, a large steering drive force corresponding to the drag torque is required, and the load on the steering drive device 20 is increased. In view of this point, the ECU 50 energizes the electric motor 32 to reduce or eliminate the drag torque when the vehicle is steered as described above.

In the example shown in FIG. 9, the left steered wheel 11L and the right steered wheel 11R are rotating in opposite directions due to the steering while the vehicle is stopped. Therefore, the energization of the electric motor 32 for reducing the drag torque is also performed so that the left and right travel drive devices 30 are energized so as to generate rotational torque in opposite directions.

A procedure for the ECU 50 to control the steering drive device 20, the travel drive device 30, and the parking lock device 40 with respect to the load removal will be described with reference to FIG.

First, in step S10, it is determined whether or not there is a lock release request to the parking lock device 40 . Specifically, it is determined whether or not an unlock command for unlocking the parking lock device 40 is output from an external ECU or the like. For example, when the driver of the vehicle 10 operates the shift lever to command release of the parking lock, the unlock command is output.

In the subsequent step S11, it is determined whether or not the hydraulic brakes for the steered wheels 11 are operating. For example, when it is detected that the driver of the vehicle 10 is stepping on the foot brake, it is determined that the hydraulic brake is operating. An electric brake driven by an electric motor may be used instead of the hydraulic brake.

If it is determined that the hydraulic brake is not operating, unlocking is prohibited. In this case, in step S12, the driver is notified that the lock cannot be released unless the foot brake is depressed. Alternatively, the driver is notified to prompt the foot brake to be stepped on. If it is determined that the hydraulic brake is operating, the parking lock device 40 is unlocked in the subsequent step S13. Specifically, the actuator 44 is released.

In subsequent step S14, it is determined whether or not the unlocking executed in step S13 was successful. For example, it is determined whether or not the lock has been successfully unlocked based on the presence or absence of detection by a sensor that detects unlock. If it is determined that unlocking has succeeded, the process of FIG. 10 ends.

If it is determined that the unlocking has failed, the occupant of the vehicle 10 is notified in step S20 that the aforementioned load removal by steering is to be executed. Further, during the unloading, the accelerator operation may be disabled in order to improve the certainty of preventing the vehicle 10 from running.

In the subsequent step S30, the hydraulic brakes of the wheels steered for unloading are released. In the example of FIGS. 1 and 9, when the steering drive device 20 is operated, the left steered wheel 11L and the right steered wheel 11R are steered. That is, in step S30, the hydraulic brakes are released for the two steered wheels 11, which are the front wheels. In other words, it can be said that the hydraulic brakes of the front wheels are partially released while maintaining the operation of the hydraulic brakes of the rear wheels.

In the subsequent step S40, it is determined which of the left steered wheel 11L and the right steered wheel 11R is the steered wheel 11 for which unlocking has failed. For example, a sensor is provided to detect the relative position of the engaging portion 421 of the engaging member 42 with respect to the gear portion 411 . Then, the presence or absence of unlocking is detected based on the detection signal of the sensor. Based on which one of the above sensors, the left or right parking lock device 40, has detected a release failure, it is determined which of the steering wheels 11 has failed to release.

In the subsequent step S50, the direction of the pressing load F2 is determined. That is, it is determined whether the lock gear 41 shown in the right column of FIG. 6 is rotated clockwise or counterclockwise. Specifically, it is determined whether the vehicle 10 is stopped on an uphill (uphill) or downhill (downhill). For example, when a tilt angle sensor for detecting the tilt angle of the vehicle body is mounted on the vehicle 10, it is determined whether the vehicle is going uphill or downhill based on the detected value of the tilt angle sensor. For example, when climbing a slope in the structure shown in FIG. 2, the pressing load F2 acts counterclockwise on the left steered wheel 11L side, and the pressing load F2 acts clockwise on the right steered wheel 11R side. For example, in the structure shown in FIG. 2, when descending a slope, the pressing load F2 acts in a direction opposite to that when ascending a slope. It should be noted that whether the vehicle is stopped on an uphill or a downhill may be determined by utilizing the travel history of the vehicle speed or GPS information.

In the subsequent step S60, the steering drive device 20 is actuated so as to steer in a direction to reduce the pressing load F2. For example, when the locked wheel determined in step S40 is the left steered wheel 11L and when it is determined in step S50 that the vehicle is climbing, the pressing load F2 acts counterclockwise. In this case, steering the vehicle in the right-turn direction causes the action shown in FIG. 8 to rotate the lock gear 41 clockwise. This reduces the pressing load F2 generated in the counterclockwise direction.

In the subsequent step S70, the traveling drive device 30 is made to exert the driving force while the steering is being performed in step S60. Specifically, of the forward rotation driving force and the reverse rotation driving force, the driving force is exerted in the direction in which the steered wheels 11 tend to rotate along with the steering in step S60. For example, in the structure shown in FIG. 2, when the traveling drive device 30 on the left steered wheel 11L side is driven to rotate forward, the lock gear 41 on the left steered wheel 11L side rotates clockwise. Therefore, for example, in step S60, in order to unlock the left steered wheel 11L side, it is assumed that the lock gear 41 is rotated clockwise by steering in the right turn direction. In this case, in step S70, the traveling drive device 30 on the left steered wheel 11L side is driven to rotate forward.

Here, as described above, when the steering drive device 20 is operated, both the left and right steered wheels 11 are operated simultaneously. Therefore, when the steering control in step S60 is executed, the steered wheels (unlocked wheels) for which unlocking has not failed are also steered in conjunction with the locked wheels. Therefore, as shown in FIG. 9, the ground contact centers P1 and P2 of both the left and right steered wheels 11 move, so the lock gear 41 on the non-locked wheel side also rotates. The direction of this rotation is opposite to the lock wheel side. In view of this point, in step S70, the traveling drive device 30 on the non-locked wheel side is also driven. The direction of this drive is opposite to the lock wheel side.

The magnitude of the driving force exerted by the traveling drive device 30 in step S60 may be the magnitude that causes the rotor 32b to rotate, or the magnitude that the rotor 32b is driven. For example, it is desirable that the magnitude is the magnitude (wheel drive force) that causes the steering wheel 11 to rotate, or less. Alternatively, it is desirable that the magnitude of the above-described drag torque (drag cancellation force) or less is smaller. Alternatively, it is desirable that the magnitude is equal to or less than the wheel driving force and equal to or greater than the drag cancellation force.

It should be noted that the ECU 50 when executing the processing of step S10 corresponds to a "determining section" that determines whether or not there is an unlock request. The ECU 50 when executing the process of step S60 corresponds to a "steering control unit" that controls steering in a direction to reduce the pressing load F2. The ECU 50 when executing the process of step S70 corresponds to a "drive control section" that drives and controls the traveling drive device 30 during steering by the steering control section. The ECU 50 when executing the process of step S30 corresponds to a "brake release control section" that releases the hydraulic brakes acting on the steered wheels 11 .

The ECU 50 when executing the process of step S50 corresponds to a "load orientation determination unit" that determines the orientation of the pressing load F2. The ECU 50 when executing the process of step S14 corresponds to a "release failure determination section" that determines whether or not the unlocking failure state has occurred. The unlock failure state is a state illustrated in FIGS. 6 and 7 in which the lock is not unlocked even though the actuator 44 is operated. The ECU 50 when executing the process of step S20 corresponds to a "notification command unit" that issues a notification command to the effect that steering by the steering control unit is to be performed.

According to the ECU 50 according to the present embodiment described above, the following effects are exhibited.

(1) The ECU 50 includes a determination section in step S10 and a steering control section in step S60, and controls steering in a direction to reduce the pressing load F2 when there is a lock release request. Therefore, it is possible to recover from the failure of unlocking due to the excessive pressing load F2, and promote the success of unlocking. In other words, since the pressing load F2 can be reduced by steering and the lock can be released, it becomes unnecessary to employ the actuator 44 having a large output.

(2) The ECU 50 has a drive control section according to step S70. Therefore, the driving force in the direction in which the steered wheels 11 tend to rotate with the steering by the steering control unit is exerted by the traveling drive device 30 during the steering control by the steering control unit. Therefore, the drag torque generated in the electric motor 32 due to the steering control can be reduced. Alternatively, the drag torque can be eliminated. Further, by setting the driving force to a magnitude that causes the rotor 32b to rotate, the steering force of the steering drive device 20 required for steering control can be reduced.

(3) The ECU 50 is provided with a load orientation determination section in step S50. The discriminating unit determines whether the direction of the road gradient at the time when the parking lock device 40 locks is uphill or downhill, or whether the final running direction is forward or backward until the lock is activated. The direction of the pressing load F2 is discriminated based on whether there is any. Therefore, the direction in which the pressing load F2 acts on the lock gear 41 can be determined. Therefore, the steering control section can select which of left-turn steering and right-turn steering the pressing load F2 can be reduced by operating the steering drive device 20 . Therefore, it is possible to avoid the possibility of damaging the parking lock device 40 by steering in the direction of increasing the pressing load F2.

(4) The ECU 50 includes a release failure determination section in step S14. Therefore, since the steering drive device 20 is operated on the condition that the release failure state is determined, the chances of operating the steering drive device 20 even when the release is successful can be reduced.

(5) The ECU 50 is provided with a notification command section according to step S20. Therefore, when steering by the steering control unit is to be executed, the user of the vehicle 10 is notified of the execution. As a result, the user who is not performing the steering operation feels uncomfortable with the automatic steering.

(Second embodiment)
In the first embodiment, the same control is used to remove the load when one wheel fails to unlock and when both wheels fail to unlock simultaneously. On the other hand, in the present embodiment, the load is removed by different control depending on whether one wheel lock release fails or when both wheel lock release fails. Hereinafter, the load release control according to the present embodiment will be described with reference to FIG. 11 .

First, in steps S10 to S20, control is performed in the same manner as in FIG. 10, and then in step S40A, it is determined whether or not both the left and right wheels of the steered wheels 11 have failed to unlock. If it is determined that both wheels have not failed to unlock, in step S100A, control for removing the load from one wheel is executed for the locked wheel. In this control, the same control as steps S30, S40, S50, S60, and S70 in FIG. 10 is executed.

If it is determined in step S40A that both wheels have failed to be unlocked, the load is released one wheel at a time as described in detail below. At this time, release of the hydraulic brake is prohibited for the steered wheels that are not subject to the unloading, and driving of the traveling drive device 30 is also prohibited.

Specifically, first, in step S30A, the left steered wheel 11L is set as the object of load removal, and the hydraulic brake associated with the left steered wheel 11L is released. In subsequent step S110A, the load of the parking lock device 40 relating to the left steering wheel 11L is removed. In this unloading control, the same control as steps S50, S60, and S70 in FIG. 10 is executed for the left steering wheel 11L. That is, the operations of the steering drive device 20 and the travel drive device 30 are controlled so as to reduce the pressing load F2 applied to the left steered wheel 11L. Therefore, when steps S30A and S110A are executed, the pressing load F2 of the left steered wheel 11L is reduced by the same action as in FIG. 9, and the lock is released.

Note that when the load is removed in steps S30 and S110A, release of the hydraulic brake for the right steered wheel 11R is prohibited, and driving of the traveling drive device 30 is also prohibited. Therefore, unlike FIG. 9, steering force acts on the right steered wheel 11R while the hydraulic brake is applied without driving the electric motor 32 . Therefore, the ground contact point of the right steering wheel 11R with the road surface does not move as shown in FIG.

In the following step S31A, the right steered wheel 11R is set as the target of the load removal, and the hydraulic brake related to the right steered wheel 11R is released. In subsequent step S120A, the load of the parking lock device 40 relating to the right steered wheel 11R is removed. In this load removal control, the same control as the control executed for the left steered wheel 11L in step S110A is executed for the right steered wheel 11R. Therefore, when steps S31A and S120A are executed, the pressing load F2 is reduced and the right steerable wheel 11R is unlocked by the same action as in FIG.

Note that when the load is removed in steps S31 and S120A, release of the hydraulic brake for the left steered wheel 11L is prohibited, and driving of the traveling drive device 30 is also prohibited. Therefore, unlike FIG. 9, the steering force acts on the left steered wheel 11L while the hydraulic brake is applied without driving the electric motor 32 . Therefore, the ground contact point of the left steering wheel 11L with the road surface does not move as shown in FIG.

Here, in a state where both wheels have failed to be unlocked at the same time, the pressing load F2 is acting on both wheels. Therefore, contrary to the present embodiment, if the hydraulic brake is released for the steered wheels that are not the object of unloading, the following concern arises. That is, when steering control is performed in a direction to reduce the pressing load F2 on the steered wheels targeted for load release, the pressed load F2 increases for the steered wheels not targeted for load release. As a result, there is concern that the parking lock device 40 may be damaged, such as damage to the engaging portion 421 or the gear portion 411 .

In response to this concern, in the present embodiment, when both wheels fail to be unlocked at the same time, the load is released from one wheel at a time. At this time, release of the hydraulic brake is prohibited for the steered wheels that are not subject to unloading, and driving of the traveling drive device 30 is also prohibited. Therefore, it is possible to avoid an increase in the pressing load F2 on the steered wheels that are not subject to load release, and to eliminate the above-mentioned concerns about damage to the parking lock device 40 .

It should be noted that when the load is released one by one in order, when the load is released secondly in step S120A, release of the hydraulic brake associated with the non-target steered wheel may be permitted. This is because if the first load release in step S110A is successful, there is no concern that pressing load F2 will increase even if the hydraulic brake is released.

(Third embodiment)
The vehicle 10 according to the first embodiment includes one steering drive device 20 for the left and right steered wheels 11, and has a structure in which the left and right steered wheels 11 are simultaneously deflected in the same direction. On the other hand, the vehicle according to the present embodiment has separate steering drive devices 20 for the left and right steered wheels 11, and has a structure in which the directions in which the left and right steered wheels 11 are deflected can be independently controlled. For example, as illustrated in FIG. 13, the structure is such that both the left and right steering wheels 11 can be deflected inward at the same time. Also, the structure is such that both the left and right steering wheels 11 can be deflected outward at the same time. The deflection operations exemplified in these are performed when the vehicle is stopped. During running, the left and right steered wheels 11 are controlled to simultaneously deflect in the same direction.

In the present embodiment, in which the vehicle 10 having such a configuration is the object of control, load removal is performed by different control depending on whether unlocking of one wheel fails or when unlocking of both wheels fails. Hereinafter, the load release control according to this embodiment will be described with reference to FIG. 12 .

First, after performing control in steps S10 to S20 in the same manner as in FIG. 10, the direction of the pressing load F2 is determined in step S50B. Specifically, similarly to step S50 in FIG. 10, it is determined whether the vehicle 10 is stopped on an uphill (uphill) or downhill (downhill). In the case of climbing a slope, the pressing load F2 acts counterclockwise on the left steered wheel 11L side, and the pressing load F2 acts clockwise on the right steered wheel 11R side. If the vehicle is descending a slope, the pressing load F2 acts in the opposite direction to that for ascending a slope.

If it is determined that the vehicle is going uphill, in the following step S60B, both the left and right steered wheels 11 are simultaneously deflected in a direction to reduce the pressing load F2. For example, when the parking lock device 40 has the structure shown in FIG. 3, both wheels are deflected inward (see FIG. 13). In the subsequent step S70B, the electric motors 32 of the traveling drive device 30 are rotationally driven for both wheels at the same time in a direction to reduce the pressing load F2. Therefore, the left and right electric motors 32 are driven to rotate in the same direction, and both wheels are driven to rotate in the normal direction when the parking lock device 40 has the structure shown in FIG.

On the other hand, if it is determined in step S50B that the vehicle is going downhill, in subsequent step S61B, both the left and right steered wheels 11 are simultaneously deflected in a direction to reduce the pressing load F2. For example, when the parking lock device 40 has the structure shown in FIG. 3, both wheels are deflected outward. In the following step S71B, the electric motors 32 of the traveling drive device 30 are rotationally driven for both wheels at the same time in a direction to reduce the pressing load F2. Therefore, the left and right electric motors 32 are driven to rotate in the same direction, and both wheels are driven in reverse when the parking lock device 40 has the structure shown in FIG.

As described above, the steering drive device 20 according to the present embodiment is configured to be able to simultaneously steer the left steered wheel 11L and the right steered wheel 11R in different directions. Then, the steering control section operates the steering drive device 20 so as to simultaneously steer the left steered wheel 11L and the right steered wheel 11R in different directions.

Therefore, if both wheels fail to unlock, both wheels can be unlocked at the same time. Therefore, compared to the case of sequentially unlocking one wheel at a time, it is possible to shorten the time from issuing an unlocking command to actually unlocking. Further, when one wheel fails to be unlocked, it is possible to eliminate the necessity of determining whether the right or left steered wheel 11 has failed to be unlocked, and to eliminate the need to sequentially unlock one wheel at a time.

(Fourth embodiment)
In the first embodiment, it is determined in step S40 which of the left and right steered wheels 11 (locked wheels) failed to be unlocked. Then, steering control is performed in a direction to reduce the pressing load F2 with respect to the discriminated locked wheel, and the load is removed from the locked wheel. On the other hand, in the present embodiment, the above determination processing is abolished, and steering control is performed in both directions of decreasing and increasing the pressing load F2.

Specifically, first, in steps S10 to S20 in FIG. 14, control is performed in the same manner as in FIG. However, hydraulic brakes are applied to the rear wheels. In the following step S60C, left and right steering is repeatedly executed. That is, while the actuator 44 is released, the pressing load F2 is alternately decreased and increased.

In subsequent step S61C, it is determined whether or not a predetermined period of time has elapsed since the steering repetition in step S60C was started. The process of step S60C is continued until the predetermined time has passed.

As described above, in the present embodiment, when it is determined that there is a lock release request, the steering control unit in step S60C performs both left-turn steering and right-turn steering regardless of the direction of the pressing load F2. , the steering drive device 20 is operated. Therefore, the pressing load F2 is repeatedly decreased and increased. At this time, since the actuator 44 is operated to release, it can be expected that the lock will be released when the pressing load F2 decreases. In this way, unlocking is prompted regardless of the direction of the pressing load F2, so the process of determining the direction of the pressing load F2 can be eliminated.

Furthermore, in the present embodiment, the steering control section in step S60C repeats the steering to both the left and right sides continuously a plurality of times. Therefore, the ground contact centers P1 and P2 fluctuate by minute amounts of movement, and the pressing load F2 is repeatedly slightly decreased and increased. At this time, since the actuator 44 is operated to release, it can be expected that the lock will be released when the pressing load F2 decreases.

(Fifth embodiment)
In this embodiment, when the steering control unit performs steering control in step S60 and the like, the operation amount of the steering drive device 20 is set as follows. In the example shown in FIG. 15, as shown in the left column, load removal is started in a state where the pressing load F2 is acting counterclockwise. When the load is removed, the operation of the steering drive device 20 is started so that the left steerable wheel 11L rotates clockwise (rotates to the right). As a result, as shown in the middle column of FIG. 15, the engaging portion 421 is separated from the gear portion 411 and the pressing load F2 is eliminated. After that, the steering control unit continues the operation of the steering drive device 20 , but stops the operation of the steering drive device 20 before the engaging portion 421 contacts the adjacent gear portion 411 .

In the following description, the magnitude of the backlash shown in the left column of FIG. 15 is assumed to be the backlash amount L1. Further, the distance by which the ground contact center P1 of the steered wheels 11 is moved by the steering control of the steering control unit is defined as a steering movement amount L2. The steering control unit controls the operation of the steering drive device 20 so that the amount of rotation of the lock gear 41 corresponding to the amount of steering movement L2 in consideration of the reduction ratio of the speed reducer 33 or the like is less than the amount of backlash L1. The amount of rotation of the lock gear 41 is the amount of movement of the gear portion 411 in the circumferential direction.

Here, if the steering amount is excessive, the engagement portion 421 is brought into contact with and pressed against the adjacent gear portion 411 after the engagement with the gear portion 411 is released. If this pressing force is large, there is concern that the parking lock device 40 may be damaged. In contrast, in the present embodiment, the steering control unit performs steering control so that the rotation amount of the lock gear 41 is less than the backlash amount L1. Therefore, the above concerns can be resolved.

(Sixth embodiment)
In the first embodiment described above, the engaging member 42 that engages with the lock gear 41 is claw-shaped with one engaging portion 421 . On the other hand, as shown in FIGS. 16 and 17, the engaging member 42A according to the present embodiment has a gear shape having a plurality of engaging portions 421A.

A power transmission portion 43A shown in FIG. 17 transmits the power of the actuator 44 to the engagement member 42A as in the first embodiment. As a result, the engagement member 42A reciprocates between the disengagement position indicated by the solid line in FIG. 17 and the engagement position indicated by the dashed line.

Even with the engagement member 42A and the power transmission section 43A having the structures described above, the same control as the steering control section and the drive control section according to the above-described embodiments can be applied.

(Seventh embodiment)
In the sixth embodiment, the plurality of engaging portions 421A have a shape that protrudes toward the rotation center of the engaging member 42A. That is, the engaging member 42A has a gear shape with internal teeth. In contrast, in the present embodiment, as shown in FIGS. 18 and 19, the plurality of engaging portions 421B are shaped to protrude away from the center of rotation of the engaging member 42B. That is, the engaging member 42B has a gear shape with external teeth.

A power transmission portion 43B shown in FIG. 19 transmits the power of the actuator 44 to the engaging member 42B as in the first embodiment. As a result, the engagement member 42B reciprocates between the disengagement position indicated by the solid line in FIG. 19 and the engagement position indicated by the dashed line.

Even with the engaging member 42B and the power transmission section 43B having the structures described above, the same control as the steering control section and the drive control section according to the above-described embodiments can be applied.

(Eighth embodiment)
In the first embodiment, the lock gear 41 is attached to the countershaft 33e. That is, when the drive shaft 12 rotates due to the execution of the steering control, the rotation force is transmitted to the lock gear 41 via the speed reducer 33 . On the other hand, in this embodiment, the lock gear 41 is attached to the drive shaft 12 as shown in FIG. That is, the structure is such that the rotational force of the drive shaft 12 is directly transmitted to the lock gear 41 . In other words, when the lock gear 41 rotates together with the steered wheels 11 , the rotation angle of the lock gear 41 matches the rotation angle of the steered wheels 11 .

Therefore, according to this embodiment, compared to the structure in which the speed reducer 33 is interposed between the lock gear 41 and the drive shaft 12, the amount of rotation of the lock gear 41 by steering control can be increased. Therefore, when executing the unloading by the steering control of the steering control section, the amount of steering required for unloading can be reduced.

(Other embodiments)
Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present disclosure. Moreover, not only the combinations of the configurations explicitly specified in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not specified unless there is a particular problem with the combination.

In each of the above embodiments, the traveling drive device 30 is provided for each of the left and right steered wheels 11 . On the other hand, the vehicle control device can be applied even to the vehicle 10 in which one traveling drive device 30 is provided for each of the left and right steered wheels 11 .

In carrying out the control of the third embodiment shown in FIG. 12, the process of determining whether or not both wheels have failed to be unlocked may be performed in the same manner as in FIG. In this case, the control of steps S50, S60B, and S61B in FIG. 12 may be executed when both wheels fail. Also, when one wheel fails, the load may be removed from the one wheel in the same manner as in step S100A.

The ECU 50 according to each of the above-described embodiments includes a release failure determination section in step S14. Then, on the condition that the release failure is detected, the steering control section executes the steering control in step S60. Alternatively, the release failure determination unit may be replaced with a release failure estimation unit. The release failure estimator determines that the release has failed when the road surface gradient of the stopped vehicle 10 is greater than or equal to a predetermined value, or when the pitch angle of the vehicle body is greater than or equal to a predetermined value. Then, the steering control unit in step S60 or the like may execute the steering control on the condition that the cancellation is deemed to have failed.

The ECU 50 according to each of the embodiments described above includes a drive control section according to step S70. On the other hand, the drive control unit may be eliminated and the driving of the traveling drive device 30 may be kept stopped during the execution of the steering control in step S60.

In the above-described fourth embodiment, the steering control unit in step S60C repeats the steering to both left and right a plurality of times in succession. Alternatively, the steering to both the left and right may be performed only once.

In the fifth embodiment, the steering control section performs steering control so that the rotation amount of the lock gear 41 is less than the backlash amount L1. On the other hand, steering control may be performed so that the amount of rotation of the lock gear 41 matches the amount of backlash L1.

The ECU 50 according to each of the above-described embodiments includes a brake release control section in step S30. When the pressing load F2 is reduced by the steering control section, the brake release control section releases the hydraulic brake acting on the steered wheels to be reduced. At this time, the hydraulic brake may be released or may be applied to the steered wheels not subject to unloading. However, it is desirable to apply a hydraulic brake to at least one of all the front and rear wheels.

In each of the above-described embodiments, the vehicle control device by the ECU 50 is applied to the vehicle 10 in which the drive shaft 12 is rotationally driven by the driving force of the electric motor 32 . On the other hand, the vehicle control device can be applied even to the vehicle 10 in which the drive shaft 12 is rotationally driven by switching between the power of the internal combustion engine and the power of the electric motor 32 . Further, the vehicle control device can be applied even to the vehicle 10 in which the electric motor 32 that rotates the drive shaft 12 by the power of the internal combustion engine is eliminated. In short, the traveling drive device that exerts the forward rotation driving force or the reverse rotation driving force transmitted to the steered wheels 11 may be the electric motor 32, the internal combustion engine, or both. good.

Further, the vehicle control device according to each of the above-described embodiments can be applied even to a vehicle that directly applies a driving force to the wheels to drive them to rotate, such as an in-wheel motor that does not pass through a drive shaft to the wheels. be.

The traveling drive device 30 shown in FIG. 2 has a structure in which an inverter 31, an electric motor 32, and a speed reducer 33 are integrally assembled, and is attached to the vehicle body as one unit. On the other hand, the inverter 31 may be separately attached to the vehicle body. Alternatively, the vehicle may be a vehicle in which the drive shaft or the wheels are directly driven to rotate by the driving force of the motor without the reduction gear 33 .

In the first embodiment described above, as shown in step S70 of FIG. 10, the driving force of the traveling drive device 30 is exerted during the execution of steering by the steering control unit, thereby reducing the steering force required for steering control. . On the other hand, the driving force of the traveling drive device 30 may be exerted after the steering is executed by the steering control unit.

10 Vehicle 11L Left Steering Wheel (Wheel) 11R Right Steering Wheel (Wheel) 20 Steering Drive Device 30 Travel Drive Device 40 Parking Lock Device 41 Lock Gear 42, 42A, 42B Engagement Member 44 Actuator F2 pressing load, S10 determination unit, S14 release failure determination unit, S20 notification command unit, S50 load orientation determination unit, S60 steering control unit, and S70 drive control unit.

Claims (10)

Lock gears (41) that rotate together with wheels (11L, 11R), engagement members (42, 42A, 42B) that engage with the lock gears to lock rotation of the wheels, and operate to release the engagement. a parking lock device (40) having an actuator (44);
A vehicle control device applied to a vehicle (10) comprising a steering drive device (20) that exerts a force to steer the wheels,
a determination unit (S10) that determines whether or not there is an unlock request for the parking lock device;
operating the steering drive device so as to steer in a direction to reduce the pressing load (F2) that the lock gear presses against the engaging member when the determination unit determines that the unlocking request is present; a steering control unit (S60);
A vehicle control device comprising: The vehicle includes a travel drive device (30) that exerts forward rotation driving force or reverse rotation driving force transmitted to the wheels,
A drive control unit (S70) that causes the traveling drive device to exert a driving force,
2. The driving force exerted by the drive control unit is, of the forward rotation driving force and the reverse rotation driving force, the driving force in the direction in which the wheels tend to rotate as the wheels are steered by the steering control unit. The vehicle control device according to . The steering control unit operates the steering drive device for both left-turn steering and right-turn steering, regardless of the direction of the pressing load when it is determined that there is the lock release request. The vehicle control device according to claim 1 or 2. 4. The vehicle control device according to claim 3, wherein said steering control unit repeats actuating said steering drive device for both left-turn steering and right-turn steering a plurality of times in succession. Whether the direction of the road gradient at the time when the parking lock device is locked is uphill or downhill, or whether the final driving direction until the lock is activated is forward or backward. Based on, a load direction determination unit (S50) that determines the direction of the pressing load,
3. The vehicle control device according to claim 1, wherein said steering control unit selects whether to operate said steering drive device for left-turn steering or right-turn steering based on a result of said determination. The steering control unit controls the operation of the steering drive device so that the amount of rotation of the lock gear is less than the amount of backlash between the lock gear and the engaging member. 1. A vehicle control device according to claim 1. Among the wheels, the wheel positioned on the left side of the vehicle is the left wheel (11L), and the wheel positioned on the right side is the right wheel (11R),
The steering drive device is configured to be able to simultaneously steer the left wheel and the right wheel in different directions,
The vehicle control device according to any one of claims 1 to 6, wherein the steering control unit operates the steering drive device so as to simultaneously steer the left wheel and the right wheel in different directions. a release failure determination unit (S14) that determines whether or not the engagement fails in response to a release request to the parking lock device, even though the actuator is operated;
The vehicle control according to any one of claims 1 to 7, wherein the steering control unit operates the steering drive device on condition that the release failure determination unit determines that the failure state exists. Device. The vehicle control device according to any one of claims 1 to 8, further comprising a notification command section (S20) that outputs a command to notify a user of the vehicle that the steering control section is to perform steering. The vehicle control according to any one of claims 1 to 9, wherein the lock gear is configured such that a rotation angle of the lock gear matches a rotation angle of the wheel when the lock gear rotates together with the wheel. Device.

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