JP2019119426A - Vehicular steering device - Google Patents

Abstract

To provide a vehicular steering device in which burden of steering of a steering wheel can be reduced even when a start switch of a vehicle drive source transits from an ON state to an OFF state during travel of a vehicle.SOLUTION: A steering device 1 comprises a steering control unit 50. The steering control unit 50 controls a steering side motor 31, a turning side motor 41, and a clutch 20 based on a detection result of each kind of sensor. When an IGSW2 transits rom an OFF state to an ON state in the case that travel of a vehicle is detected by a vehicle speed sensor 46 during the IGSW2 is in the OFF state, the steering control unit 50 gives assist power a steering wheel 11 and executes EPS control for causing the steering device 1 to function as an EPS through at least one control of the steering side motor 31 and the turning side motor 41.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle steering system.

  Conventionally, a so-called steer-by-wire (hereinafter referred to as "SBW") type steering device capable of connecting and disconnecting a power transmission path between a steering wheel and turning wheels is known (Patent Document 1). The steering device described in Patent Document 1 includes a clutch that connects and disconnects a power transmission path between a steering wheel and steered wheels, a steering motor that is a generation source of a steering reaction force applied to the steering wheel, and steered wheels. A steering side motor that is a source of steering force to be steered, a clutch, a steering side motor, and a steering control device that controls the steering side motor are provided. In this steering device, when the ignition switch (hereinafter referred to as "IGSW") as a start switch is switched from the off state to the on state (starting state of the vehicle) at the time of start of the vehicle, etc. The power transmission path between the steering wheel and the steering wheel is mechanically cut off. Further, in this steering device, when the IGSW is switched from the on state to the off state, such as when the vehicle is stopped, the power transmission path between the steering wheel and the steered wheels is mechanically connected by the clutch.

  The steering control device applies a steering reaction force to the steering wheel by the steering motor and steers the steered wheels by the steering motor when the power transmission path between the steering wheel and the steered wheels is disconnected by the clutch. The SBW control is executed by generating the turning force. When the power transmission path between the steering wheel and the steered wheels is connected by the clutch, the steering control device controls the driver's steering operation, for example, through control of at least one of the steering motor and the steering motor. Executes control of an electric power steering device (hereinafter referred to as "EPS") to be assisted.

JP, 2015-123864, A

  By the way, although the IGSW is in the off state, the vehicle may be traveling. For example, when the IGSW in the on state is switched to the off state while the vehicle is traveling, or when the vehicle stopped on the slope starts to travel even though the IGSW is in the off state. . When the vehicle is traveling even though the IGSW is in the off state, even if the IGSW in the off state is switched to the on state, the steering control device does not operate until the vehicle is stopped. The steering motor and the steering motor were not controlled. That is, when the IGSW in the off state is switched to the on state while the vehicle is traveling, the steering wheel can perform steering with so-called manual steering in which neither EPS control nor SBW control is performed. As a result, the driver's steering wheel steering load is increased.

  An object of the present invention is to provide a vehicle steering system capable of reducing the steering load of the steering wheel even when the start switch of the vehicle drive source transitions from the off state to the on state while the vehicle is traveling.

  A vehicle steering apparatus capable of achieving the above object comprises: a steering unit including a steering wheel steered by a driver; and a steering unit including steered wheels steered according to the steering of the steering wheel by the driver. When the start switch of the vehicle drive source is in the on state, the power transmission path between the steering unit and the steering unit is disconnected, and when the start switch is in the off state, the steering unit and A clutch in a state in which a power transmission path with the steering unit is connected, a steering side motor for applying a steering reaction force to the steering wheel in a state in which the clutch is disconnected, and a turning for turning the steered wheels A steering apparatus for a vehicle comprising: a rudder side motor; a traveling detection unit for detecting a traveling state of the vehicle; and a control unit for controlling the clutch, the steering side motor, and the steered side motor And the control unit is configured to connect the clutch when the start switch is switched from the off state to the on state when the start switch is in the off state and travel of the vehicle is detected. An assist force for assisting the driver's steering is applied to the steering wheel through the control of at least one of the side motor and the steered side motor.

  According to this configuration, when the start switch is in the off state and travel of the vehicle is detected, the steering side motor and the steered side motor are in the state where the clutch is connected when the start switch transitions from the off state to the on state. An assist force is applied to the steering wheel from at least one of the two. As described above, when the start switch is in the off state and travel of the vehicle is detected, when the start switch changes from the off state to the on state, the steering device functions as an electric power steering device to drive by the assist force. Since the steering of the person's steering wheel is assisted, the load of steering of the driver's steering wheel is reduced.

  A vehicle steering apparatus that can achieve the above object includes a steering unit including a steering wheel steered by a driver, a steering unit that steers steered wheels in accordance with the steering of the steering wheel by the driver, and a vehicle When the start switch of the drive source is in the on state, the power transmission path between the steering unit and the steering unit is disconnected, and when the start switch is in the off state, the steering unit and the rotation are switched. A clutch in a state in which a power transmission path with a rudder part is connected, a steering side motor for applying a steering reaction force to the steering wheel in a state in which the clutch is disconnected, and a steering side for turning the steered wheels A steering apparatus for a vehicle, comprising: a motor; a traveling detection unit that detects a traveling state of the vehicle; and a control unit that controls the clutch, the steering motor, and the steered motor. In the case where the start switch is in the off state and traveling of the vehicle is detected, the control unit turns the steering while the clutch is disconnected when the start switch transitions from the off state to the on state. The steering wheel is steered through control of the side motor, and a steering reaction force is applied to the steering wheel through control of the steering motor.

  According to this configuration, when the start switch is off and travel of the vehicle is detected, the steered side motor is turned by the steered side motor while the clutch is disconnected when the start switch transitions from the off state to the on state. While turning the vehicle, the steering motor applies a steering reaction force to the steering wheel. As described above, when the start switch is off and travel of the vehicle is detected, the steering device functions as a steer-by-wire device when the start switch transitions from the off state to the on state. The load on steering is reduced.

In the above-described vehicle steering apparatus, the travel detection unit is preferably a vehicle speed sensor that detects a vehicle speed that is a traveling speed of the vehicle.
According to this configuration, it is possible to more appropriately grasp that the vehicle is traveling based on the vehicle speed detected by the vehicle speed sensor.

  According to the vehicle steering system of the present invention, the steering load of the steering wheel can be reduced even when the start switch of the vehicle drive source transitions from the off state to the on state during traveling of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the steering apparatus of 1st Embodiment. 6 is a flowchart showing an execution procedure of EPS control when the ignition switch changes from the off state to the on state while the vehicle is traveling in the steering apparatus of the first embodiment. 12 is a flowchart showing an execution procedure of SBW control when the ignition switch changes from the off state to the on state while the vehicle is traveling in the steering device of the second embodiment.

First Embodiment
Hereinafter, a first embodiment in which the steering control device is applied to a steer-by-wire steering device will be described.

  As shown in FIG. 1, the vehicle is equipped with a steering device 1 and an IGSW 2 that is a start switch for starting an engine that is a drive source of the vehicle. When the engine is started, the IGSW 2 transitions from the off state to the on state, and outputs the ignition on signal Son. When the engine is stopped, the IGSW 2 transitions from the on state to the off state, and outputs the ignition off signal Soff.

  The vehicle steering system 1 has a steering shaft 12 connected to a steering wheel 11. A pinion shaft 13 is provided at an end (lower end) of the steering shaft 12 opposite to the steering wheel 11. The lower end portion of the pinion shaft 13 is connected to a steered shaft 15 extending in a direction intersecting the pinion shaft 13 via a first rack and pinion mechanism 14. The pinion teeth 13a of the pinion shaft 13 mesh with the rack teeth 15a of the steered shaft 15, whereby a first rack and pinion mechanism 14 is configured. Further, both ends of the steering shaft 15 are connected to the left and right steered wheels 17, 17 via tie rods 16, 16 respectively. Therefore, in the steering device 1, the rotational movement of the steering shaft 12 is converted to reciprocating linear movement in the axial direction (left and right direction in FIG. 1) of the steered shaft 15 via the first rack and pinion mechanism 14. As the steered shaft 15 linearly moves with the rotation operation of the steering wheel 11, the steered angle θt of the steered wheels 17, 17 is changed. The steering shaft 12, the pinion shaft 13 and the steered shaft 15 function as a power transmission path between the steering wheel 11 and the steered wheels 17, 17.

<Clutch>
The steering device 1 has a clutch 20 interposed between the steering shaft 12 and the pinion shaft 13. As clutch 20, for example, an electromagnetic clutch that switches on / off (switching between a connected state and a disconnected state) by energization to an exciting coil is employed. When the excitation coil is energized, the clutch 20 is in the disconnected state, and when the excitation coil is not energized, the clutch 20 is in the connected state. When the clutch 20 is disconnected, the power transmission path between the steering wheel 11 and the steered wheels 17, 17 is mechanically disconnected. On the other hand, when the clutch 20 is connected, the power transmission path between the steering wheel 11 and the steered wheels 17 and 17 is mechanically connected.

<Configuration for Generating Steering Reaction Force: Reaction Force Unit>
The steering device 1 includes a reaction force unit 30 (steering unit) as a configuration for generating a steering reaction force. The steering reaction force is a force acting in the direction opposite to the direction in which the steering wheel 11 is operated by the driver. By giving this steering reaction force to the steering wheel 11 (steering shaft 12), it is possible to give the driver an appropriate feeling of response.

The reaction force unit 30 includes a steering motor 31, a reduction mechanism 32, a rotation angle sensor 33, and a torque sensor 34.
The steering motor 31 is a generation source of a steering reaction force. As steering side motor 31, for example, a three-phase brushless motor is employed. The rotation shaft 31 a of the steering motor 31 is coupled to the steering shaft 12 via the speed reduction mechanism 32. The speed reduction mechanism 32 is provided at a portion closer to the steering wheel 11 than the clutch 20 in the steering shaft 12. By applying the motor torque of the steering motor 31 to the steering shaft 12, a steering reaction force is applied to the steering wheel 11.

  The rotation angle sensor 33 detects the rotation angle θs0 of the rotation shaft 31 a of the steering motor 31. The rotation angle θs0 of the steering motor 31 is used to calculate the steering angle. The steering motor 31 and the steering shaft 12 interlock with each other via the speed reduction mechanism 32. There is a correlation between the rotation angle θs 0 of the steering motor 31 and the rotation angle of the steering shaft 12. There is also a correlation between the rotation angle of the steering shaft 12 and the steering angle of the steering wheel 11. Therefore, the steering angle can be obtained based on the rotation angle θs0 detected by the rotation angle sensor 33.

  The torque sensor 34 is provided at a portion closer to the steering wheel 11 than the speed reduction mechanism 32 (clutch 20) in the steering shaft 12. The torque sensor 34 detects a steering torque Th applied to the steering shaft 12 as the steering wheel 11 is rotated.

<Configuration for generating steering force: steering unit>
The steering device 1 includes a steering unit 40 (a steering unit) as a configuration for generating a steering force. The steering force is a force for steering the steered wheels 17, 17.

The steering unit 40 has a steering side motor 41, a speed reduction mechanism 42, and a rotation angle sensor 43.
The turning side motor 41 is a source of turning force. For example, a three-phase brushless motor is employed as the steering side motor 41. The rotation shaft 41 a of the turning side motor 41 is connected to the pinion shaft 44 via the speed reduction mechanism 42. The lower end portion of the pinion shaft 44 is connected to a steered shaft 15 extending in a direction intersecting the pinion shaft 44 via a second rack and pinion mechanism 45. A second rack and pinion mechanism 45 is configured by the pinion teeth 44 a of the pinion shaft 44 meshing with the rack teeth 15 b of the steered shaft 15. The torque of the turning side motor 41 is applied to the pinion shaft 44, whereby the pinion shaft 44 rotates. The rotational movement of the pinion shaft 44 is converted into an axial reciprocating linear movement of the steered shaft 15 via the second rack and pinion mechanism 45. Thereby, the torque of the turning side motor 41 is given to the turning shaft 15 via the pinion shaft 44 as turning force.

The rotation angle sensor 43 detects the rotation angle θt0 of the turning side motor 41.
<Steering control device>
The steering device 1 includes a steering control device 50 as a control unit. The steering control device 50 controls the steering motor 31, the steering motor 41, and the clutch 20 based on the detection results of various sensors. As various sensors, a rotation angle sensor 33, a torque sensor 34, a rotation angle sensor 43, and a vehicle speed sensor 46 are used. The vehicle speed sensor 46 is provided in the vehicle as a traveling detection unit that detects the traveling state of the vehicle. The vehicle speed sensor 46 detects a vehicle speed V which is a traveling speed of the vehicle. The steering control device 50 also obtains an ignition on signal Son and an ignition off signal Soff from the IGSW 2. The steering control device 50 determines that the IGSW 2 is in the on state or the off state based on the ignition on signal Son and the ignition off signal Soff.

  The steering control device 50 switches connection / disconnection of the clutch 20 based on whether the condition for connecting the clutch 20 is satisfied. As a condition for connecting the clutch 20, for example, when the ignition off signal Soff is input from the IGSW 2 while the vehicle is at a stop, or when the turning angles of the steered wheels 17, 17 reach a predetermined angle, that is, the end contact Can be mentioned. The steering control device 50 shifts the clutch 20 from the connected state to the disconnected state when the ignition on signal Son is input from the IGSW 2 while the vehicle is stopped. Further, when the ignition off signal Soff is input from the IGSW 2 while the vehicle is stopped, the steering control device 50 shifts the clutch 20 from the disconnection state to the connection state.

  The steering control device 50 executes a reaction force control that causes the steering wheel 11 to generate a steering reaction force through the control of the steering side motor 31 when the clutch 20 is in the disengaged state, and a steered wheel through the control of the steering side motor 41. By executing steering control for turning 17 and 17, SBW control for causing the steering device 1 to function as SBW is performed. In addition, when the clutch 20 is in the connected state, the steering control device 50 performs EPS control to apply an assist force based on the steering torque Th to the steering wheel 11 through the control of at least one of the steering motor 31 and the steering motor 41. Run.

<Repulsive force control>
The steering control device 50 calculates a target steering reaction force for generating a steering reaction force based on the steering torque Th and the vehicle speed V. Then, the steering control device 50 calculates a target steering angle based on the calculated target steering reaction force and the steering torque Th. The steering control device 50 calculates a steering angle correction amount by executing angle feedback control of the steering angle so that the actual steering angle follows the target steering angle, and sets the steering angle correction amount to the target steering reaction force. A steering reaction force command value is calculated by adding. The steering control device 50 performs a reaction control by supplying the steering motor 31 with a current required to generate a steering reaction force corresponding to the steering reaction force command value.

<Steering control>
The steering control device 50 also calculates a pinion angle which is an actual rotation angle of the pinion shaft 44 based on the rotation angle θt0 detected by the rotation angle sensor 43. The pinion angle is a value reflecting the turning angle θt of the turning wheels 17, 17. The steering control device 50 calculates a target pinion angle using the target steering angle. Then, the steering control device 50 executes angle feedback control based on the deviation between the target pinion angle and the actual pinion angle, thereby controlling power supply to the steered side motor 41 so as to eliminate the deviation. , To perform steering control.

<When IGSW is switched from off to on while the vehicle is traveling>
Further, when the traveling of the vehicle is detected by the vehicle speed sensor 46 when the IGSW 2 is in the off state, the steering control device 50 keeps the clutch 20 in the connected state when the IGSW 2 transitions from the off state to the on state. An assist force is applied to the steering wheel 11 through the control of at least one of the steering motor 31 and the steering motor 41. That is, when the traveling of the vehicle is detected by the vehicle speed sensor 46 when the IGSW 2 is in the off state, the steering control device 50 causes the steering device 1 to function as an EPS when the IGSW 2 transitions from the off state to the on state. Execute EPS control.

  The steering control device 50 applies an assist force based on the steering torque Th to the steering wheel 11 by at least one of the steering motor 31 and the steering motor 41 at the time of EPS control. Here, all the necessary assist force may be applied by the steering side motor 31 or the steering side motor 41, and the steering side motor 31 and the steering side motor 41 respectively apply the necessary assist force by half. You may do it.

Next, an execution procedure of the EPS control when the IGSW 2 changes from the off state to the on state while the vehicle is traveling will be described.
As shown in the flowchart of FIG. 2, the steering control device 50 determines whether traveling of the vehicle is detected (step S1).

  When traveling of the vehicle is detected (YES in step S1), the steering control device 50 determines whether the IGSW 2 has transitioned from the off state to the on state (step S2). The steering control device 50 determines whether or not the vehicle is traveling based on, for example, whether the vehicle speed V detected by the vehicle speed sensor 46 is larger than a vehicle speed threshold.

When it is determined that the IGSW 2 has shifted from the off state to the on state (YES in step S2), the steering control device 50 executes EPS control (step S3).
The steering control device 50 ends the process when the traveling of the vehicle is not detected (NO in step S1) or when the IGSW 2 has not transitioned from the off state to the on state (NO in step S2).

Hereinafter, the operation and effects of the first embodiment will be described.
(1) When traveling of the vehicle is detected when the IGSW 2 is in the off state, at least one of the steering motor 31 and the steering motor 41 assists the steering wheel 11 when the IGSW 2 transitions to the on state. The steering device 1 functions as an EPS by giving As a result, even when the IGSW 2 transitions to the on state while the vehicle is traveling, the steering force of the driver's steering wheel 11 is reduced by the amount that assists the driver's steering of the steering wheel 11 by the assist force. Be done.

  (2) Since the vehicle speed V detected by the vehicle speed sensor 46 is an amount directly indicating that the vehicle is traveling, it is better to grasp whether the vehicle is traveling or not based on the vehicle speed V more appropriately. Is possible.

Second Embodiment
Hereinafter, a second embodiment in which the steering control device is applied to a steer-by-wire steering device will be described. Here, differences from the first embodiment will be mainly described.

  As shown in FIG. 1, when the traveling of the vehicle is detected by the vehicle speed sensor 46 when the IGSW 2 is in the off state, the steering control device 50 connects the clutch 20 when the IGSW 2 transitions from the off state to the on state. Move from the state to the disconnected state. Then, the steering control device 50 steers the steered wheels 17 and 17 through the control of the steering side motor 41 after the transition of the clutch 20 to the disengaged state is completed, and steers the steering wheel 11 to the steering wheel 11 through the control of the steering side motor 31. Apply a reaction force. That is, when the traveling of the vehicle is detected by the vehicle speed sensor 46 when the IGSW 2 is in the off state, the steering control device 50 causes the steering device 1 to function as the SBW when the IGSW 2 transitions from the off state to the on state. Execute SBW control.

Next, an execution procedure of SBW control when the IGSW 2 transitions from the off state to the on state while the vehicle is traveling will be described.
As shown in the flowchart of FIG. 3, the steering control device 50 determines whether the travel of the vehicle is detected (step S1), and when the travel of the vehicle is detected (YES in step S1), the IGSW 2 It is determined whether the off state has transitioned to the on state (step S2).

  When it is determined that the IGSW 2 has shifted from the off state to the on state (YES in step S 2), the steering control device 50 shifts the clutch 20 from the connection state to the disconnection state (step S 4) and executes SBW control ( Step S5).

  The steering control device 50 ends the process when the traveling of the vehicle is not detected (NO in step S1) or when the IGSW 2 has not transitioned from the off state to the on state (NO in step S2).

Hereinafter, the operation and effects of the second embodiment will be described.
(3) When traveling of the vehicle is detected when the IGSW 2 is in the off state, when the IGSW 2 transitions to the on state, the clutch 20 is shifted from the connected state to the disconnected state, and the steered wheel motor 41 The steering motor 17 applies a steering reaction force to the steering wheel 11 while turning the wheels 17 and 17. The steered wheels 17, 17 are steered by driving the steered side motor 41 according to the driver's steering of the steering wheel 11, and a steering reaction force is applied to the steering wheel 11 by the steered side motor 31. As a result, the driver can steer the steering wheel 11 with an appropriate feeling of response. As described above, even when the IGSW 2 transitions to the on state while the vehicle is traveling, the steering device 1 functions as the SBW, whereby the driver's steering load on the steering wheel 11 is reduced.

Each embodiment may be modified as follows. Moreover, the following other embodiments can be combined with each other to the extent that there is no technical contradiction.
-In each embodiment, although the vehicle speed sensor 46 was adopted as a traveling detection part which detects a traveling state of vehicles, it is not restricted to this. For example, an acceleration sensor may be employed as the traveling detection unit. At the time of start of the vehicle, an acceleration is generated according to the increase of the vehicle speed V, so that the traveling of the vehicle can be detected based on the acceleration.

The clutch 20 may be a mesh type clutch or a friction type clutch.
In each embodiment, in addition to the EPS control or the SBW control, the driving support control based on the command of the driving support from the external control device may be performed.

  In each embodiment, the vehicle is a vehicle having a so-called internal combustion engine adopting an engine as a drive source, but may be a so-called electric vehicle adopting a motor as a drive source. In the case of an electric vehicle, the start switch is a switch for starting a motor as a drive source.

  DESCRIPTION OF SYMBOLS 1 ... Steering apparatus, 2 ... IGSW (starting switch), 11 ... Steering wheel, 12 ... Steering shaft, 13 ... Pinion shaft, 15 ... Steering shaft, 17 ... Steering wheel, 20 ... Clutch, 30 ... Reaction force unit, 31 ... Steering side motor, 33 ... Rotation angle sensor, 34 ... Torque sensor, 40 ... Steering unit, 41 ... Steering side motor, 43 ... Rotation angle sensor, 44 ... Pinion shaft, 46 ... Vehicle speed sensor (travel detection unit), 50: steering control device (control unit), Son: ignition on signal, Soff: ignition off signal, Th: steering torque, V: vehicle speed, θs0, θt0: rotation angle, θt: steering angle.

Claims (3)

A steering unit provided with a steering wheel steered by a driver;
A steering unit provided with steered wheels that are steered according to the steering of the steering wheel by a driver;
The power transmission path between the steering unit and the steering unit is disconnected when the start switch of the vehicle drive source is in the on state, and the steering unit and the steering unit are in the state where the start switch is in the off state. A clutch in a state in which a power transmission path between the steering unit and the steering unit is connected;
A steering motor that applies a steering reaction force to the steering wheel when the clutch is disengaged;
A steering side motor for steering the steered wheels;
A traveling detection unit that detects a traveling state of the vehicle;
A steering apparatus for a vehicle, comprising: a control unit configured to control the clutch, the steering motor, and the steered motor.
The control unit
When the start switch transitions from the off state to the on state when the start switch is in the off state and travel of the vehicle is detected, the steering motor and the steered side motor are connected while the clutch is connected A steering apparatus for a vehicle, which applies an assist force for assisting a driver's steering to the steering wheel through at least one control. A steering unit provided with a steering wheel steered by a driver;
A steering unit that steers the steered wheels according to the steering of the steering wheel by a driver;
When the start switch of the vehicle drive source is in the on state, the power transmission path between the steering unit and the steering unit is disconnected, and when the start switch is in the off state, the steering unit and the steering unit are A clutch in a state in which a power transmission path between the steering unit and the steering unit is connected;
A steering motor that applies a steering reaction force to the steering wheel when the clutch is disengaged;
A steering side motor for steering the steered wheels;
A traveling detection unit that detects a traveling state of the vehicle;
A steering apparatus for a vehicle, comprising: a control unit configured to control the clutch, the steering motor, and the steered motor.
The control unit
When the start switch is turned off and the traveling of the vehicle is detected, when the start switch transitions from the off state to the on state, the steered wheels are controlled through the control of the steered side motor in a state where the clutch is disconnected. A steering apparatus for a vehicle, which steers the steering wheel and applies a steering reaction force to the steering wheel through control of the steering motor.   The vehicle steering apparatus according to claim 1, wherein the traveling detection unit is a vehicle speed sensor that detects a vehicle speed that is a traveling speed of the vehicle.