JP2007185985A - Steering device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device of a steer-by-wire type vehicle which turning-controls a steered wheel surely according to an erroneous operation of a connecting means mechanically connecting an operation part and the steered wheel. <P>SOLUTION: A connecting device 30 is equipped with an input shaft 33 and an output shaft 34 which are stored in a housing 31. A gap sensor 44 which detects a displacement amount of the input shaft 33 based on a physical quantity such as eddy current changing accompanied by the displacement of the input shaft 33 is assembled to the connecting device 30. An electronic control unit 45 determines whether or not the connecting device is in a connecting state based on an output voltage Vgap corresponding to the displacement amount of the input shaft 33 outputted from the gap sensor 44. If the connecting device 30 is in the connecting state by the determination, the electronic control unit 45 shuts off the supply of a driving current to a turning actuator 24, and stops an operation of the actuator 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides an operation unit operated by a driver, a turning means for turning a steered wheel, a turning force corresponding to an operation of the operation unit, and the turning force to the turning Steering force generating means for transmitting to the means, connecting means for mechanically connecting or releasing the operating portion and the steering means, and steering for controlling the operation of the steering force generating means The present invention relates to a steering-by-wire vehicle steering apparatus including a control unit.

  2. Description of the Related Art In recent years, a steering by wire type vehicle steering apparatus in which a mechanical connection between an operation unit operated by a driver and a steered wheel is released has been actively developed. In this type of steering device, since the connection between the operation unit and the steered wheels is released, an operation amount input to the operation unit (for example, a steering wheel) is detected, and a steering gain ( That is, the steered wheels are steered by actuating the steered actuator as the steered force generating means with the steered amount (actuated amount) taking into account the ratio of the operation amount of the operation unit and the steered wheel steered amount). Can do. Thereby, the amount of operation of an operation part required in order to steer a steered wheel large can be made small, and the burden at the time of a driving | operation can be reduced.

  By the way, in this steering-by-wire vehicle steering device, as described above, the mechanical connection between the operation unit and the steered wheel is normally released, and the steered wheel is operated according to the operation of the operation unit by the driver. In order to turn the steering wheel, it is indispensable that at least the steering actuator is operating normally. In other words, when an abnormality occurs in the steering actuator, there is a possibility that the steered wheels cannot be steered appropriately. Therefore, when an abnormality occurs in the steering actuator, it is necessary to directly transmit the operation of the operation unit by the driver to the steered wheels. For this reason, a steering-by-wire vehicle steering apparatus is provided with a fail-safe mechanism that mechanically connects the operation unit and the steered wheels when an abnormality occurs in the steered actuator.

  As a steering-by-wire vehicle steering apparatus employing such a fail-safe mechanism, for example, a vehicle steering apparatus shown in Patent Document 1 below is known. This conventional vehicle steering apparatus includes an operation member for steering the vehicle, a steering mechanism for turning a steering wheel of the vehicle, a steering actuator for generating a driving force to be given to the steering mechanism, and an operation member And a common driver for supplying a drive voltage to the steering actuator and the reaction force actuator. In addition, the conventional vehicle steering apparatus includes a relay that is interposed between the power source and the common driver and cuts off the supply of current when the detected current value is an abnormal value. Furthermore, the conventional vehicle steering apparatus includes a clutch mechanism that can mechanically connect or disconnect the operation member and the steering mechanism, and if the current value of the current supplied to the common driver is an abnormal value, the clutch Clutch control means for bringing the mechanism into a connected state is also provided.

In this conventional vehicle steering apparatus, when the current value supplied from the power source to the common driver becomes an abnormal value that can be taken when an abnormality occurs in the steering actuator, reaction force actuator, or common driver, for example, The current supply to the steering actuator and the reaction force actuator is cut off by being cut. Further, when the relay is disconnected in this way, the clutch control means brings the clutch mechanism into a connected state. Thus, the driver can directly steer the steering wheel.
JP 2002-127919 A

  However, in the conventional vehicle steering apparatus, the clutch that realizes the operation or stop of the fail-safe mechanism, in other words, the mechanical connection or disconnection between the operation member (operation unit) and the steering mechanism (steering means). The operation status of the mechanism (connecting means) is not accurately grasped, and in particular, a response when the clutch mechanism (connecting means) malfunctions is not specifically disclosed. For example, if the current value of the current supplied to the shared driver temporarily becomes an abnormal value and then becomes a normal value, the relay is restored and power supply from the power source to the shared driver is resumed. Can be considered. Then, it is conceivable that the clutch control means performs control so that the clutch mechanism (connecting means) is changed from the connected state to the separated state (that is, the non-connected state).

  At this time, for example, in the case where the clutch mechanism (coupling means) is controlled so as to be in a non-coupled state by the clutch control means, for example, when the coupled state is maintained due to a mechanical failure, the steering actuator May be transmitted to the operation member (operation unit). In this case, the driver may perceive unintended displacement of the operation member (operation unit), so-called self-steer, and may feel uncomfortable.

  The present invention has been made to cope with the above-described problems, and its purpose is to control the turning of a steered wheel in a reliable manner in response to a malfunction of a connecting means that mechanically connects the operation unit and the steered wheel. An object of the present invention is to provide a steering-by-wire vehicle steering apparatus.

  In order to achieve the above object, the feature of the present invention is that an operation unit operated by a driver, a turning means for turning a steered wheel, and a turning force corresponding to the operation of the operation unit are generated. And a turning force generating means for transmitting the turning force to the turning means, a connecting means for mechanically connecting or releasing the operation unit and the turning means, and the turning In a steering-by-wire vehicle steering apparatus including a steering control unit that controls the operation of the force generation unit, the steering control unit is configured such that the connection unit mechanically connects the operation unit and the steering unit. In conjunction with the transition to the connected state, the operation amount is controlled by limiting the operation amount of the turning force generating means.

  According to this, when the connecting means is in the connected state, the steering control means can limit the operation amount of the turning force generating means in conjunction with the connected state. As a result, even when the connecting means maintains the connected state due to, for example, a malfunction caused by the occurrence of a mechanical failure, the amount of operation of the turning force generating means is limited, so that the occurrence of self-steer is prevented. It can be surely prevented. On the other hand, when the connecting means is in a disconnected state in which the mechanical connection between the operation unit and the steering means is released, the operation amount of the steering force generating means is not limited. The advantages of the vehicle steering device can be used effectively.

  In this case, the turning control means includes a detecting means for detecting a connected state of the connecting means or a non-connected state of the connecting means that releases the mechanical connection between the operation unit and the turning means. If it is determined that the detection unit is in the connected state, the supply of power to the steering force generation unit may be cut off and the stop control may be performed. Further, the connecting means is configured to abut the input shaft connected to the operation unit side, the output shaft connected to the steering means side, and the input shaft and the output shaft, and to separate them from each other. The detection means may detect the connection state of the connection means based on the amount of displacement of the input shaft or the output shaft by the drive means. Furthermore, the detection means may be a gap sensor that detects a displacement amount of the input shaft or the output shaft based on a physical quantity that varies with a displacement of the input shaft or the output shaft, for example.

  According to these, the turning control means detects, for example, the displacement amount of the input shaft or the output shaft constituting the connecting means using a detecting means such as a gap sensor, and the connecting means malfunctions based on the detection result. It can be determined whether or not the connected state is maintained. And if a connection means is in a connection state by malfunctioning, a steering control means can interrupt | block supply of the electric power with respect to a steering force generation means, and can perform stop control. As a result, the connected state due to the malfunction of the connecting means can be detected very accurately and the operation of the turning force generating means in the connected state can be stopped, so that the occurrence of self-steer due to the malfunction can be more reliably performed. Can be prevented.

  In another aspect of the present invention, the turning control means includes power supply control means that is integrally assembled with the connecting means and supplies or cuts off electric power to the turning force generating means. The power supply control means cuts off the supply of power to the turning force generating means in conjunction with a connecting operation for the connecting means to mechanically connect the operation unit and the turning means. There is also.

  In this case, the connection means causes the input shaft connected to the operation unit side, the output shaft connected to the steering means side, and the input shaft and the output shaft to abut against each other and be separated from each other. A fixed contact provided on a power line for supplying power to the turning force generating means, and the fixed contact. A movable contact that is separated from or in contact with the input shaft, and the movable contact is separated from the fixed contact in response to a contact operation between the input shaft and the output shaft by the drive unit of the coupling unit, and the input shaft by the drive unit It is good to comprise from the separation / contact means which makes the said movable contact contact the said fixed contact according to the separation operation | movement of an output shaft. And a contact means for displacing the movable contact in the direction of the fixed contact according to the displacement of the connection means in a direction away from the output shaft of the input means. The movable contact may be configured by biasing means that applies a biasing force in a direction away from the fixed contact with respect to the displacement of the movable contact.

  According to these, for example, the contact operation or the separation operation between the input shaft and the output shaft constituting the connection means can be directly (mechanically) transmitted to the power supply control means. The power supply control means can quickly cut off the supply of power to the turning force generating means in conjunction with the contact operation between the input shaft and the output shaft of the connecting means, that is, the connecting operation of the connecting means. it can. Therefore, it is not necessary for the steering control means to determine whether or not the connecting means is in the connected state, and more specifically, it is not necessary to determine whether or not the connecting means is malfunctioning. Can be stopped, and the occurrence of self-steer can be prevented at an early stage. Further, in this case, the configuration of the steering device itself can be simplified to reduce the manufacturing cost.

a. First Embodiment Hereinafter, a vehicle steering apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a vehicle steering apparatus according to this embodiment. The vehicle steering device includes a steering operation device 10 operated by a driver, a steering device 20 that steers left and right front wheels FW1 and FW2 as steered wheels according to the operation of the driver, a steering operation device 10, A connecting device 30 for mechanically connecting the steering device 20 is provided.

  The steering operation device 10 includes a steering handle 11 as an operation unit that is rotated by a driver. The steering handle 11 is fixed to the upper end of the steering input shaft 12, and a reaction force actuator 13 is assembled to the steering input shaft 12 at an intermediate portion thereof. The reaction force actuator 13 includes an electric motor and a speed reduction mechanism, and applies a predetermined reaction force to the steering input shaft 12 (steering handle 11) according to the operation of the steering handle 11 by the driver.

  The steered device 20 includes a steered shaft 21 that extends in the left-right direction of the vehicle. The left and right front wheels FW1, FW2 are connected to both ends of the steered shaft 21 via tie rods 22a, 22b and knuckle arms 23a, 23b so as to be steerable. Further, on the outer periphery of the steered shaft 21, a steered actuator 24 as a steered force generating unit that transmits a predetermined steered force to the steered shaft 21 is assembled.

  The steering actuator 24 includes an electric motor, a speed reduction mechanism, and a screw feed mechanism. When the electric motor is driven to rotate and generates a predetermined turning force in accordance with the operation of the steering handle 11 by the driver, the rotation of the electric motor is decelerated by the reduction mechanism and the screw feed mechanism and the turning shaft 21 is driven. Is converted to an axial displacement. Thus, the steered shaft 21 is displaced in the axial direction by the transmitted steered force, and the left and right front wheels FW1 and FW2 are steered to the left and right as the steered shaft 21 is displaced.

  In addition, when an abnormality occurs in the steering system such as an abnormal operation of the steering actuator 24 on the steered shaft 21, a turning operation of the steering handle 11 by the driver (more specifically, a rotation input by the turning operation). A transmission mechanism 25 for transmitting force is assembled. The steering mechanism 25 includes a pinion gear 25a that meshes with a rack tooth 21a formed on a part of the steering shaft 21, and a transmission shaft 25b that transmits rotation to the pinion gear 25a. The transmission shaft 25 b of the transmission mechanism 25 is connected to the coupling device 30 via the flexible cable K.

  The connecting device 30 is assembled to the lower end of the steering input shaft 12, and when an abnormality occurs in the steering system, in particular, the turning actuator 24 of the turning device 20, the steering operation device 10 and the turning device 20 are connected. It is mechanically connected. As shown in FIG. 2, the coupling device 30 includes a housing 31. The housing 31 is connected to the steering input shaft 12 through a ball bearing 32a at one end thereof. In the housing 31, an input shaft 33 for inputting the rotation of the steering input shaft 12 and an output shaft for outputting the rotation (rotational force) of the steering input shaft 12 transmitted through the input shaft 33 to the flexible cable K. 34 is accommodated.

  The input shaft 33 includes, for example, a shaft body 33a formed from a solid round bar. As shown in FIG. 2, the shaft body 33a is rotatable and axially rotated by a bearing 32b (for example, a slide bearing or a rotary ball spline bearing) assembled in the housing 31 at a substantially central portion thereof. It is supported so that it can be displaced. Further, the rotation of the steering input shaft 12 can be efficiently transmitted to one end portion of the shaft body 33a, that is, the connection portion with the steering input shaft 12, and the displacement in the axial direction relative to the steering input shaft 12 can be performed. Serration grooves 33a1 are formed.

  In addition, a disk portion 33b is integrally formed on the other end of the shaft body 33a, that is, on the side facing the output shaft 34. Thereby, the disk part 33b can rotate and displace to an axial direction integrally with the shaft main body 33a, and outputs the rotation (rotation force) input from the steering input shaft 12 in the contact state, as will be described later. It can be transmitted to the shaft 34. Here, a friction member 33b1 is provided on the surface (contact surface) of the disk portion 33b facing the output shaft 34 in order to appropriately transmit the rotation (rotational force). Further, in the vicinity of the serration groove 33a1 formed in the shaft body 33a, a flange portion 33c having an outer diameter dimension substantially the same as the outer diameter dimension of the steering input shaft 12 is formed.

  The output shaft 34 includes, for example, a shaft main body 34 a formed from a solid round bar, and the shaft main body 34 a is rotatably supported with respect to the housing 31 by a ball bearing 32 c assembled in the housing 31. ing. A flexible cable K is integrally connected to one end of the shaft body 34a. On the other hand, a disk portion 34b is integrally formed on the other end of the shaft body 34a, that is, on the side facing the input shaft 33. The disk portion 34 b has substantially the same outer diameter as the disk portion 33 b of the input shaft 33. Here, a friction member 34b1 is provided on the surface (contact surface) of the disk portion 34b facing the input shaft 33 in order to appropriately input rotation (rotational force).

  Further, the coupling device 30 includes an electromagnet 35 that separates the disk portion 33b of the input shaft 33 and the disk portion 34b of the output shaft 34 from each other. The electromagnet 35 is formed of a coil wound in an annular shape, and is assembled to an end surface portion of the steering input shaft 12 facing the flange portion 33c of the input shaft 33 as shown in FIG. Then, the disk portion 33b of the input shaft 33 and the disk portion 34b of the output shaft 34 are separated from each other by sucking the flange portion 33c in accordance with operation control by the electric control device 40 described later.

  Further, the coupling device 30 includes a spring 36 that applies a biasing force for bringing the disk portion 33b of the input shaft 33 and the disk portion 34b of the output shaft 34 into contact with each other. As shown in FIG. 2, the spring 36 is disposed between the end surface of the input shaft 33 where the serration groove 33 a 1 is formed and the bottom surface of the serration hole formed in the steering input shaft 12. Here, the spring 36 is always assembled so as to be reduced from the free length. As a result, the spring 36 always applies a biasing force to the input shaft 33 in a direction extending to the free length. Therefore, the input shaft 33 is displaced in the axial direction by the biasing force, so that the disk portion 33b and the disk portion 34b of the output shaft 34 are brought into contact with each other. The electromagnet 35 and the spring 36 constitute the driving means of the present invention.

  Next, the electric control device 40 that electrically controls the operations of the reaction force actuator 13, the steering actuator 24, and the electromagnet 35 will be described. As shown in FIG. 1, the electric control device 40 includes a steering angle sensor 41, a turning angle sensor 42, a vehicle speed sensor 43, and a gap sensor 44. The steering angle sensor 41 is assembled to the steering input shaft 12, detects the rotation angle from the neutral position of the steering handle 11, and outputs it as the steering angle θ. The turning angle sensor 42 is assembled to a housing (not shown) on the outer periphery of the turning shaft 21, detects a displacement in the axial direction from the reference position of the turning shaft 21, and outputs it as a turning angle δ. The steering angle θ and the turning angle δ are represented by setting the neutral position to “0”, the right angle as a positive value, and the left direction as a negative value. The vehicle speed sensor 43 detects the vehicle speed of the vehicle and outputs it as the vehicle speed V.

  The gap sensor 44 is assembled to the coupling device 30 to detect the amount of displacement of the input shaft 33 based on a physical quantity that changes with the displacement of the shaft 33, for example, a change in eddy current or capacitance. An output voltage Vgap corresponding to the detected displacement amount is output. More specifically, as shown in FIG. 2, the gap sensor 44 is configured such that its detection part faces the side surface of the disk part 33 b of the input shaft 33 in contact with the disk part 34 b of the output shaft 34. , And assembled in a mounting hole formed in the housing 31 of the coupling device 30. The gap sensor 44 outputs an output voltage Vgap that is equal to or higher than a predetermined voltage Vo when the disk portion 33b and the disk portion 34b are in contact with each other. Further, as shown in FIG. 3, the gap sensor 44 is in a state where the disc portion 33b and the disc portion 34b are separated from each other, that is, when the detection portion is not opposed to the side surface of the disc portion 33b. An output voltage Vgap less than a predetermined voltage Vo is output.

  These sensors 41 to 44 are connected to an electronic control unit 45 as shown in FIG. The electronic control unit 45 includes a microcomputer including a CPU, a ROM, a RAM, and the like as main components, and controls operations of the reaction force actuator 13, the steering actuator 24, and the electromagnet 35 by executing predetermined programs. Control circuits 46, 47 and 48 for controlling the operation of the reaction force actuator 13, the turning actuator 24 and the electromagnet 35 are connected to the output side of the electronic control unit 45. The control circuits 46, 47, and 48 are respectively connected to the battery 50, and control the operation by supplying a predetermined drive current to the reaction force actuator 13, the steering actuator 24, and the electromagnet 35. ing.

  Next, the operation of the steering apparatus according to the first embodiment configured as described above will be described. When an ignition switch (not shown) is turned on by the driver, the electronic control unit 45 repeatedly performs an operation check of the steering system, more specifically, an operation check of the turning actuator 24. That is, the electronic control unit 45 executes a preset check program (not shown), and monitors, for example, a drive current value flowing through the electric motor of the steering actuator 24 via the control circuit 47. If the operation of the steering actuator 24 is normal based on the value of the drive current flowing through the electric motor, the electronic control unit 45 operates the coupling device 30 to connect the steering operation device 10 and the steering device 20. Release the mechanical connection. Hereinafter, the operation of the coupling device 30 will be specifically described. If an abnormality occurs in the operation of the turning actuator 24, the electronic control unit 45 maintains the mechanical connection state between the steering operation device 10 and the turning device 20 by the connecting device 30. Yes. In this case, as described later, the operation of the steering actuator 24 is stopped or the operation is limited.

  When releasing the mechanical connection by the connecting device 30, the electronic control unit 45 supplies a predetermined drive current to the coil forming the electromagnet 35 of the connecting device 30 via the control circuit 48. Thus, when a predetermined drive current is supplied, the electromagnet 35 is magnetized and attracts the flange portion 33 c of the input shaft 33. As a result, the input shaft 33 supported by the bearing 32b so as to be axially displaceable is displaced in the direction of the steering input shaft 12 against the urging force of the spring 36, and as shown in FIG. 3, the disk portion 33b and the output shaft 34 disk portions 34b are separated from each other. That is, the connecting device 30 switches from the connected state to the non-connected state by performing the non-connecting operation.

  However, for example, when a mechanical failure such as the influence of foreign matter existing inside the housing 31 or poor lubrication between the shaft main body 33a and the bearing 32b occurs, the displacement of the input shaft 33 in the axial direction is hindered. There is a case. In this case, although a predetermined current is supplied to the coil constituting the electromagnet 35 and the electromagnet 35 is appropriately magnetized and attracts the flange portion 33c, the disk portion of the input shaft 33 The contact state between 33b and the disk portion 34b of the output shaft 34 is maintained.

  When the electronic control unit 45 operates the turning actuator 24 in the situation where the contact state, that is, the connected state is maintained in this way, the transmission mechanism is accompanied by the axial displacement of the turning shaft 21 as will be described later. The 25 pinion gears 25 a and the transmission shaft 25 b rotate integrally, and the rotation is transmitted to the steering handle 11 via the flexible cable K, the output shaft 34, the input shaft 33 and the steering input shaft 12. As a result, so-called self-steering occurs in which the steering handle 11 rotates against the driver's intention.

  Therefore, the electronic control unit 45 constantly monitors the operating state of the coupling device 30 by repeatedly executing the coupling state confirmation program shown in FIG. 4 every predetermined short time, and prevents the occurrence of self-steering. Specifically, the electronic control unit 45 starts execution of the connection state confirmation program in step S10, and in step S11, whether or not the output voltage Vgap input from the gap sensor 44 is equal to or higher than a predetermined voltage Vo. Determine whether.

  That is, as described above, the gap sensor 44 outputs the output voltage Vgap that is equal to or higher than the predetermined voltage Vo when the disk portion 33b of the input shaft 33 and the disk portion 34b of the output shaft 34 are in contact with each other. Therefore, the electronic control unit 45 compares the output voltage Vgap from the gap sensor 44 with the predetermined voltage Vo, so that the disk portion 33b of the input shaft 33 and the disk portion 34b of the output shaft 34 are in contact with each other. It can be determined whether or not it is in a connected state, in other words, whether or not the input shaft 33 has been displaced.

  Based on this, when the output voltage Vgap is less than the predetermined voltage Vo, the electronic control unit 45 is in a disconnected state in which the disk portion 33b of the input shaft 33 and the disk portion 34b of the output shaft 34 are separated from each other. , "No" is determined, and the process proceeds to step S13. In step S13, the execution of the connection state confirmation program is temporarily terminated. In this case, since it has been confirmed that the coupling device 30 is in the non-coupled state, the electronic control unit 45 can react the reaction force actuator 13 and the steering actuator according to the turning operation of the steering handle 11 by the driver. 24 is controlled in the normal operating manner.

  More specifically, when the detected steering angle θ output from the steering angle sensor 41 is input, the electronic control unit 45 determines a predetermined reaction force based on the input detected steering angle θ. That is, the electronic control unit 45 determines a reaction force corresponding to the detected steering angle θ by using the detected steering angle θ and a predetermined relationship (for example, a proportional relationship or an exponential relationship) set in advance. The electronic control unit 45 supplies a predetermined drive current via the control circuit 46 so that the reaction force applied to the steering handle 11 matches the determined reaction force, and the electric motor of the reaction force actuator 13 is supplied. Drives and controls the rotation. Thereby, a reaction force according to the turning operation of the steering handle 11 by the driver is applied. Therefore, the driver can turn the steering handle 11 while perceiving the applied reaction force.

Further, when the electronic control unit 45 inputs the detected steering angle θ output from the steering angle sensor 41, the electronic steering unit 45 sets the target turning angle δf of the left and right front wheels FW1, FW2 according to the input detected steering angle θ, for example, Calculate according to Equation 1.
δf = θ · G Equation 1
However, G in Equation 1 is the ratio of the steering angle δ to the steering angle θ, that is, the steering gain. Here, as shown in FIG. 5, the steering gain G is determined so that its magnitude changes according to the vehicle speed V detected by the vehicle speed sensor 43. That is, when the vehicle speed V is low, the steering gain G is set to be large, so that a large target turning angle δf with respect to the detected steering angle θ is calculated according to the above equation 1. When the vehicle speed V is high, the steering gain G is set to be small, so that a small target turning angle δf with respect to the detected steering angle θ is calculated according to the above equation 1.

  Then, the electronic control unit 45 drives and controls the rotation of the electric motor of the turning actuator 24 via the control circuit 47 so that the left and right front wheels FW1, FW2 coincide with the calculated target turning angle δf. Specifically, the electronic control unit 45 supplies a predetermined drive current to the electric motor until the actual turning angle δ detected by the turning angle sensor 42 matches the calculated target turning angle δf. . As a result, a predetermined turning force is transmitted to the turning shaft 21, and the left and right front wheels FW1, FW2 are turned to the calculated target turning angle δf, so that the driver can perform a small turning operation of the steering handle 11. Thus, the vehicle can be turned easily.

  On the other hand, if the output voltage Vgap input from the gap sensor 44 is greater than or equal to the predetermined voltage Vo in step S11 of the connection state confirmation program, the electronic control unit 45 determines “Yes”. That is, in this case, although the electronic control unit 45 supplies power to the coil of the electromagnet 35 via the control circuit 48, the annular portion 33b of the input shaft 33 and the annular portion 34b of the output shaft 34 Is still in contact. Therefore, in this state, when the electric motor of the steering actuator 24 is driven to rotate, the above-described self-steer occurs. For this reason, in step S12, the electronic control unit 45 stops the operation by interrupting the supply of electric power to the steering actuator 24, that is, the supply of a predetermined drive current.

  Thus, in a state where the operation of the steering actuator 24 is stopped, the left and right front wheels FW1, FW2 are directly steered in response to the turning operation of the steering handle 11 by the driver. That is, when the steering handle 11 is rotated by the driver, the rotation (rotational force) accompanying the operation is transmitted via the steering input shaft 12, the input shaft 33, the output shaft 34, and the flexible cable K. Is transmitted to. Thereby, the transmission shaft 25b and the pinion gear 25a rotate integrally, and the turning shaft 21 to which the rotation of the pinion gear 25a is transmitted via the rack teeth 21a is displaced in the axial direction. Accordingly, the left and right front wheels FW1 and FW2 are directly steered in response to the turning operation of the steering handle 11. In this case, the electronic control unit 45 appropriately controls the operation of the reaction force actuator 13 and applies an assist force to the steering input shaft 12 to reduce the burden of the turning operation of the steering handle 11 by the driver. It is good to make it.

  After the processing of step S12, the electronic control unit 45 proceeds to step S13 and temporarily ends the execution of the connection state confirmation program. Then, the electronic control unit 45 starts to execute the connection state confirmation program after a predetermined short period of time, and the mechanical failure is resolved, and the output voltage Vgap is less than the predetermined voltage Vo in step S11. For example, since the connecting device 30 is in the non-connected state, the steering actuator 24 is operated in a normal manner.

  As can be understood from the above description, according to the first embodiment, the electronic control unit 45 interrupts the supply of drive current to the steering actuator 24 in conjunction with the transition of the coupling device 30 to the coupled state. can do. At this time, the electronic control unit 45 detects the amount of displacement of the input shaft 33 constituting the coupling device 30 using the gap sensor 44, and based on the detection result, whether or not the coupling device 30 is in the coupled state. More specifically, it can be determined whether or not the connecting means is malfunctioning. If the connecting device 30 is in a connected state due to a malfunction, the electronic control unit 45 can stop the power supply to the steered actuator 24 and stop control.

  As a result, the connected state due to the malfunction of the connecting device 30 can be detected very accurately and the operation of the steering actuator 24 in the connected state can be stopped, so that the occurrence of self-steer due to the malfunction can be more reliably performed. Can be prevented. On the other hand, when the coupling device 30 is in a non-coupled state in which the mechanical connection between the steering handle 11 and the steering device 20 is released, the steering actuator 24 can be operated in a normal operation mode. For this reason, it is possible to effectively use the advantages of the steering apparatus for a vehicle adopting the steering-by-wire system, such as being able to turn the vehicle greatly with a small amount of turning operation of the steering handle 11.

  Here, in step S12 of the connection state confirmation program described above, the drive current to the steering actuator 24 is cut off to stop the operation of the actuator 24. However, instead of this, a target turning angle δf that coincides with the detected steering angle θ may be calculated, and the turning actuator 24 may be operated based on the target turning angle δf. More specifically, the situation where self-steering occurs is that the connecting device 30 is in the connected state, and the left and right front wheels FW1, FW2 so that the turning actuator 24 has the target turning angle δf calculated according to Equation 1 above. Occurs when steering. That is, in a situation where the detected steering angle θ and the target turning angle δf calculated by multiplying the steering angle θ by the steering gain G are greatly different, the turning actuator 24 turns the left and right front wheels FW1, FW2 to the target turning. Occurs when turning to an angle δf.

  Therefore, when the coupling device 30 is in the coupled state, in the above formula 1, for example, the steering gain G is set to “1”, the target turning angle δf equal to the detected steering angle θ is calculated, and this target turning The steering actuator 24 may be operated so that the left and right front wheels FW1, FW2 are steered to the steering angle δf. Thus, the occurrence of self-steering can also be prevented by operating the steering actuator 24, in other words, limiting the operation amount of the steering actuator 24.

  In the first embodiment, the input shaft 33 is rotatably supported by the bearing 32b and can be displaced in the axial direction, and the output shaft 34 is rotatably supported by the ball bearing 32c. In other words, the input shaft It implemented so that 33 might be displaced to an axial direction. However, if necessary, the output shaft 34 is rotatably supported by the bearing 32b and can be displaced in the axial direction, and the input shaft 33 is rotatably supported by the ball bearing 32c. In other words, the output shaft 34 is axially supported. It is also possible to carry out such a displacement. In this case, the gap sensor 44 may detect the amount of displacement of the output shaft 34 in the axial direction.

b. Second Embodiment Next, a second embodiment of the present invention will be described. In the first embodiment described above, the electronic control unit 45 repeatedly executes the connection state confirmation program using the output voltage Vgap from the gap sensor 44 assembled to the connection device 30, thereby connecting the connection device 30. It was carried out to determine the state or unconnected state. Then, when the coupling device 30 is in the coupled state, the supply of drive current to the steering actuator 24 is cut off, or the steering actuator 24 is operated so that the target steering angle δf coincides with the detected steering angle θ. By limiting the above, the occurrence of self-steer was prevented.

  In this way, instead of the electronic control unit 45 determining the connection state of the connection device 30 and stopping the operation of the steering actuator 24 (or limiting the operation amount) based on the determination, the connection of the connection device 30 is performed. It is also possible to mechanically stop the operation of the steering actuator 24 according to the state. Hereinafter, although this 2nd Embodiment is described in detail, the same code | symbol is attached | subjected to the same part as the said 1st Embodiment, and the detailed description is abbreviate | omitted.

  The vehicle steering apparatus according to the second embodiment also includes a steering operation device 10 and a steering device 20 as shown in FIG. In the second embodiment, the steering operation device 10 and the steering device 20 are mechanically connected by the connection device 130.

  As shown in FIG. 7, the coupling device 130 has substantially the same structure as the coupling device 30 of the first embodiment. That is, the connection device 130 includes a housing 131 as in the first embodiment, and is connected to the steering input shaft 12 via the ball bearing 132a at one end thereof. Further, the input shaft 133 and the output shaft 134 are accommodated in the housing 131 as in the first embodiment.

  The input shaft 133 includes a shaft body 133a having a large diameter portion and a small diameter portion. The large-diameter portion of the shaft main body 133a is supported by a bearing 132b (for example, a slide bearing or a rotary ball spline bearing) assembled in the housing 131 so as to be rotatable and displaceable in the axial direction.

  On the other hand, the small diameter portion of the shaft body 133a is integrally fixed to the inner race of the ball bearing 132d. The outer race of the ball bearing 132d is assembled to a linear bearing 132e indicated by a broken line fixed in the housing 131. Thus, the shaft body 133a is rotatably supported by the ball bearing 132d, and the shaft body 133a and the ball bearing 132d are supported by the linear bearing 132e so as to be axially displaceable.

  In addition, a disk portion 133b is formed on the large diameter portion of the shaft body 133a, that is, on the side facing the output shaft 134, as in the first embodiment. A friction member 133b1 is provided on the contact surface of the disk portion 133b. A flange portion 133c is formed in the small diameter portion of the shaft main body 133a. Further, as in the first embodiment, the rotation of the steering input shaft 12 is efficiently transmitted to the small diameter portion of the shaft main body 133a, and the axial displacement with respect to the steering input shaft 12 is enabled. A serration groove 133a1 is formed.

  As in the first embodiment, the output shaft 134 includes a shaft main body 134a, and the shaft main body 134a is rotatably supported with respect to the housing 131 by a ball bearing 132c assembled in the housing 131. . As in the first embodiment, the flexible cable K is integrally connected to one end portion of the shaft body 134a, and the disk portion 134b is integrally formed to the other end portion of the shaft body 134a. Yes. A friction member 134b1 is provided on the contact surface of the disk portion 134b.

  The coupling device 130 is also provided with an electromagnet 135 and a spring 136 that operate in the same manner as the electromagnet 35 and the spring 36 in the coupling device 30 of the first embodiment. Note that the arrangement of the electromagnet 135 and the spring 136 is also the same as the arrangement of the electromagnet 35 and the spring 36 of the coupling device 30 as shown in FIG.

  In addition, the connecting device 130 in the second embodiment automatically supplies power to the control circuit 47 (more specifically, the turning actuator 24), that is, a predetermined driving current when the device 130 is connected. A relay 60 is integrally assembled as power supply control means for cutting off the power. As shown in FIG. 6, the relay 60 is provided on a power supply line that connects the battery 50 and the control circuit 47, and as shown in FIG. 7, the fixed contact 61a on the battery 50 side and the control circuit 47 side. The fixed contact 61 comprised from the fixed contact 61b is provided. The movable contact 62 comes into contact with the fixed contact 61.

  The movable contact 62 is separated from or comes into contact with the fixed contact 61 according to the connection state or non-connection state of the connection device 130. For this reason, the arm 63 as a contact means for mechanically transmitting the axial displacement of the input shaft 133 is integrally fixed to the movable contact 62 in a connected state or a non-connected state of the connecting device 130. Yes. The arm 63 is provided so as to be able to come into contact with a ball bearing 132 d fixed to a small diameter portion of the input shaft 133. The arm 63 is in contact with the ball bearing 132d and the contact portion 63a formed in a tapered shape in accordance with the unconnected state of the connecting device 130, that is, the axial displacement of the input shaft 133 in the direction of the steering input shaft 12. By making contact, the movable contact 62 is displaced in a direction in contact with the fixed contact 61.

  Further, a spring 64 as an urging means for returning to the original position shown in FIG. 7, that is, a position separated from the fixed contact 61, is assembled to the movable contact 62 with respect to the displacement in the direction of the fixed contact 61 by the arm 63. It has been. As a result, the movable contact 62 is maintained in the original position by the biasing force of the spring 64 in the connected state of the connecting device 130.

  In addition, the electric control device 40 in the second embodiment is configured in the same manner as in the first embodiment except that the gap sensor 44 in the first embodiment is omitted. And the electronic control unit 45 in this 2nd Embodiment also controls the action | operation of the reaction force actuator 13, the steering actuator 24, and the electromagnet 135 by execution of a predetermined program, respectively.

  Next, the operation of the steering apparatus according to the second embodiment configured as described above will be described. Also in the second embodiment, the electronic control unit 45 performs an operation check of the steering actuator 24 when the ignition switch is operated, and if no abnormality has occurred, the steering operation device 10 and the steering device 20 Release the mechanical connection. Hereinafter, the operation of the connecting device 130 will be described in detail. Also in this second embodiment, if an abnormality occurs in the operation of the steering actuator 24, the electronic control unit 45 mechanically connects the steering operation device 10 and the steering device 20 by the connecting device 130. The state is to be maintained. Also in this case, the operation of the steering actuator 24 is stopped as will be described later.

  In releasing the mechanical connection by the connecting device 130, also in the second embodiment, the electronic control unit 45 performs a predetermined drive on the coil forming the electromagnet 135 of the connecting device 130 via the control circuit 48. Supply current. Thus, when a predetermined drive current is supplied, the electromagnet 135 is magnetized and attracts the flange portion 133c of the input shaft 133. As a result, the input shaft 133 and the ball bearing 132d supported so as to be axially displaceable by the bearing 132b and the linear bearing 132e are integrally displaced in the direction of the steering input shaft 12 against the urging force of the spring 136. Then, as shown in FIG. 8, the disk portion 133b of the input shaft 133 and the disk portion 134b of the output shaft 134 are separated from each other, and the connecting device 130 is switched from the connected state to the non-connected state.

  Further, as described above, the input shaft 133 and the ball bearing 132d are integrally displaced in the direction of the steering input shaft 12, so that the ball bearing 132d and the contact portion 63a formed on the arm 63 of the relay 60 are in contact with each other. The arm 63 is displaced together with the movable contact 62 in the direction of the fixed contact 61. When the flange portion 133c of the input shaft 133 is displaced to a position where it contacts the end face of the steering input shaft 12, the fixed contact 61 and the movable contact 62 come into contact with each other, and the battery 50 and the control circuit 47 are electrically connected. The Thereby, only when the coupling device 130 is in the non-coupled state, the battery 50 and the control circuit 47 can be automatically connected to each other. Therefore, the electronic control unit 45 controls the operation of the steering actuator 24 in a normal manner as in the non-connected state of the connecting device 30 in the first embodiment only when the connecting device 130 is in the non-connected state. be able to.

  On the other hand, also in the second embodiment, when a mechanical failure occurs, the axial displacement of the input shaft 133 in the direction of the steering input shaft 12 may be hindered. In this situation, when the steering actuator 24 is operated in a normal operation mode, self-steering occurs. However, when the input shaft 133 is not displaced in the axial direction, in other words, when the coupling device 130 is maintained in the coupled state, the fixed contact 61 and the movable contact 62 of the relay 60 are separated from each other as shown in FIG. Maintained in a state. As a result, the battery 50 and the control circuit 47 are electrically disconnected, and as a result, the supply of drive current to the steering actuator 24 is automatically shut off. Therefore, when the coupling device 130 is in the coupled state, the operation of the steering actuator 24 is automatically stopped, and the occurrence of self-steer can be completely prevented. As described above, when the operation of the steering actuator 24 is stopped, similarly to the first embodiment, the operation of the reaction force actuator 13 is appropriately controlled to rotate the steering handle 11 by the driver. An assist force for reducing the burden may be applied to the steering handle 11.

  As can be understood from the above description, in the second embodiment, the steering is automatically turned in the connected state without confirming whether the operating state of the connecting device 130 is the connected state or the unconnected state. The supply of the drive current to the actuator 24 is cut off, and the drive current can be automatically supplied to the steered actuator 24 in the disconnected state. Therefore, it is not necessary to determine whether or not the coupling device 130 is in a connected state, and more specifically, it is not necessary to determine whether or not the coupling device 130 is malfunctioning, and the occurrence of self-steer is prevented at an early stage. be able to. Further, in this case, the configuration of the steering device itself can be simplified to reduce the manufacturing cost.

  The implementation of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the object of the present invention.

  For example, the gap sensor 44 in the first embodiment can be assembled to the coupling device 130 in the second embodiment. Thereby, for example, even when the abnormality occurs in the operation of the relay 60 and the battery 50 and the control circuit 47 are electrically connected even though the connecting device 130 is in the connected state, By controlling the operation of the steering actuator 24 based on the output voltage Vgap from the sensor 44, the occurrence of self-steer can be reliably prevented.

  In this case, when the coupling device 130 is switched from the non-connected state to the connected state due to an abnormality in the steering system, the input shaft 133 may not be displaced in the axial direction due to a mechanical failure. In this situation, the left and right front wheels FW1, FW2 are steered based on the output voltage Vgap from the gap sensor 44, for example, by restricting the operation of the steering actuator 24, as in the first embodiment. Can do.

  Moreover, in each said embodiment, the connection of the steering apparatus 20 and the connection apparatuses 30 and 130 was implemented using the flexible cable K. FIG. As a result, it is possible to reliably transmit the turning operation of the steering handle 11 by the driver to the steering device 20 when an abnormality occurs, while ensuring the mountability of the steering device on the vehicle. However, instead of the flexible cable K, for example, a rigid shaft may be used, or any other device that can transmit the turning operation of the steering handle 11 by the driver to the steering device 20. It may be used. Also by this, the turning operation of the steering handle 11 by the driver can be reliably transmitted to the steering device 20 when an abnormality occurs.

  Further, in each of the above embodiments, the case where an operation abnormality has occurred in the steering actuator 24 as an abnormality occurring in the steering system is exemplified, but the operation abnormality of the reaction force actuator 13 or the abnormality of the electronic control unit 45 is performed. Even when the power supply is interrupted, the connecting devices 30 and 130 may be maintained in the connected state. In this case, after the connecting devices 30 and 130 shift to the connected state when the reaction force actuator 13 is abnormally operated or when the steering actuator 24 is abnormally operated, the actuators 13 and 24 are operating normally. It is preferable to reduce the operating force of the steering handle 11 by the driver by appropriately driving the electric motor on the side. Moreover, even if it is a case where the abnormality of the vehicle containing the operation abnormality of the steering actuator 24 has not generate | occur | produced, you may make the connection apparatuses 30 and 130 transfer from a non-connection state to a connection state as needed.

  In the above embodiments, the coupling devices 30 and 130 employ the electromagnets 35 and 135 and the springs 36 and 136. However, instead of these, the disk portions 33b and 133b of the input shafts 33 and 133 and the disk portions 34b and 134b of the output shafts 34 and 134 can be separated from each other at normal times, such as a solenoid. Any drive means may be used as long as the disk portions 33b, 133b and the output shafts 34, 134 can be brought into contact with each other.

  In each of the above embodiments, the electromagnets 35 and 135 are disposed on the end surface portion of the steering input shaft 12, and the springs 36 and 136 are disposed between the end surfaces of the shaft bodies 33 a and 133 a and the bottom surface of the serration hole of the steering input shaft 12. Was carried out. However, the disk portions 33b, 133b of the input shafts 33, 133 and the disk portions 34b, 134b of the output shafts 34, 134 are separated from each other at normal times, and the disk portions 33b, 133b and the output shafts 34, 134 are brought into contact with each other at an abnormal time. The electromagnets 35 and 135 and the springs 36 and 136 may be arranged at any location as long as an urging force can be applied so as to make contact.

  In each of the above embodiments, the steering handle 11 that is rotated to steer the vehicle is used. However, instead of this, for example, a joystick-type steering handle that is linearly displaced may be used, or any other one that can be operated by the driver and instructed to steer the vehicle is used. May be.

  Furthermore, in each said embodiment, the steering actuator 24 was assembled | attached to the steering shaft 21, and the left and right front wheels FW1 and FW2 were steered by displacing this steering shaft 21 linearly. However, instead of this, the steered shaft 21 is configured by a rack bar, and in addition to the configuration of each of the above embodiments, a pinion gear that meshes with the rack teeth provided on the steered shaft 21 is fixed to the lower end. An input shaft may be provided, and the turning actuator 24 may transmit rotation to the turning input shaft.

1 is a schematic view of a steering-by-wire vehicle steering apparatus according to a first embodiment of the present invention. It is sectional drawing for demonstrating the connection state of the connection apparatus of FIG. It is sectional drawing for demonstrating the non-connection state of the connection apparatus of FIG. It is a flowchart of the connection state confirmation program performed with the electronic control unit of FIG. It is a figure for demonstrating the steering gain determined by the electronic control unit of FIG. It is the schematic of the steering apparatus of the steering by wire system vehicle which concerns on 2nd Embodiment of this invention. It is sectional drawing for demonstrating the connection state of the connection apparatus of FIG. 6, and the cutting state of a relay. It is sectional drawing for demonstrating the non-connection state of the connection apparatus of FIG. 6, and the connection state of a relay.

Explanation of symbols

FW1, FW2 ... front left and right wheels, 10 ... steering operation device, 11 ... handle, 12 ... steering input shaft, 13 ... reaction force actuator, 20 ... steered device, 21 ... steered shaft, 30, 130 ... coupling device, 31, 131 ... Housing, 33, 133 ... Input shaft, 33a, 133a ... Shaft body, 33b, 133b ... Disc part, 34, 134 ... Output shaft, 34a, 134a ... Shaft body, 34b, 134b ... Disc part, 35, 135 ... Electromagnet, 36, 136 ... Spring, 40 ... Electric control device, 44 ... Electronic control unit, 46, 47, 48 ... Control circuit

Claims (7)

An operation unit operated by the driver, a steering means for turning the steered wheels, and a turning force according to the operation of the operation unit are generated and the turning force is transmitted to the steering means. Steering force generating means, connecting means for mechanically connecting or releasing the operation unit and the steering means, and steering control means for controlling the operation of the steering force generating means. In a steering-by-wire vehicle steering apparatus provided,
The steering control means operates by limiting the amount of operation of the steering force generating means in conjunction with the transition to a connected state in which the connecting means mechanically connects the operation unit and the steering means. A steering-by-wire vehicle steering apparatus characterized by controlling. The steering apparatus for a steering-by-wire vehicle according to claim 1,
The steering control means
A detecting means for detecting a connected state of the connecting means or a non-connected state of the connecting means that has released the mechanical connection between the operation unit and the steering means;
A steering-by-wire vehicle steering apparatus characterized in that when the detection means determines that the vehicle is in a connected state, the supply of electric power to the steering force generation means is cut off and stop control is performed. In the steering device for a steering-by-wire vehicle according to claim 2,
The connecting means includes
An input shaft connected to the operation unit side, an output shaft connected to the steering means side, and a drive means for bringing the input shaft and the output shaft into contact with each other and separating from each other It is composed of
The detection unit detects a connection state of the connection unit based on a displacement amount of the input shaft or the output shaft by the drive unit, and is a steering-by-wire type steering apparatus for a vehicle In the steering device for a steering-by-wire vehicle according to claim 3,
A steering-by-wire type vehicle characterized in that the detection means is a gap sensor that detects a displacement amount of the input shaft or the output shaft based on a physical quantity that changes with displacement of the input shaft or the output shaft. Steering device. The steering apparatus for a steering-by-wire vehicle according to claim 1,
The steering control means
Power supply control means that is assembled integrally with the connection means and supplies or cuts off power to the steering force generation means,
The power supply control means cuts off the supply of power to the turning force generating means in conjunction with a connecting operation for the connecting means to mechanically connect the operation unit and the turning means. A steering-by-wire vehicle steering apparatus characterized by the above. In the steering device for a steering-by-wire vehicle according to claim 5,
The connecting means includes
An input shaft connected to the operation unit side, an output shaft connected to the steering means side, and a drive means for bringing the input shaft and the output shaft into contact with each other and separating from each other It is composed of
The power supply means;
A fixed contact provided on a power supply line for supplying electric power to the turning force generating means, a movable contact that is separated from or in contact with the fixed contact, and the input shaft that is driven by the connecting means. The movable contact is separated from the fixed contact according to the contact operation with the output shaft, and the movable contact is brought into contact with the fixed contact according to the separation operation between the input shaft and the output shaft by the driving means. And a steering-by-wire vehicle steering apparatus. The steering device for a steering-by-wire vehicle according to claim 6,
The separation means;
A contact means for displacing the movable contact in the direction of the fixed contact in response to a displacement of the input means in a direction away from the output shaft of the connection means, and a displacement of the movable contact by the contact means A steering-by-wire vehicle steering apparatus characterized by comprising an urging means for applying an urging force to the movable contact in a direction away from the fixed contact.

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