JP2005247171A - Steering device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of preventing disposition of a steering wheel and a static toe angle of a wheel without mechanically connecting a steering wheel with a steering gear. <P>SOLUTION: This steering device of a vehicle comprises a rotation operating member SW, an actuator A driven according to an operation amount of the rotation operating member SW, and wheels W, W steered by driving only the actuator A without connecting to the rotation operating member SW. The device is equipped with a wheel tow angle detection means 70, and a rotation block means B blocking the rotation of the rotation operating member SW under a condition that an ignition switch is turned off. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in a so-called steer-by-wire vehicle steering apparatus in which a rotation operation member is not mechanically coupled to a steering wheel of a vehicle.

  In general, in a steer-by-wire type steering device, for example, a steering gear that steers a wheel including a rack having both ends connected to a wheel and a pinion gear that drives the rack is not mechanically connected to the steering wheel. The detection means for detecting the operation amount of the steering wheel and the actuator for driving the pinion gear according to the operation amount detected by the detection means, and when the driver operates the steering wheel, according to the operation amount, Steering wheels are steered (see, for example, Patent Documents 1, 2, and 3).

In these conventional steer-by-wire type steering devices, the steering wheel and the pinion of the steering gear are mechanically connected to each other for fail-safe or prevention of positional deviation between the rotation operation member and the direction of the wheel. Means are also provided.
Japanese Patent Laying-Open No. 2001-106111 (Embodiment of the Invention, FIG. 1) JP 2002-87308 A (Embodiment of the Invention, FIG. 1) JP 2002-211141 (Embodiment of the Invention, FIG. 1)

  However, the conventional steering device described above has the following problems.

  In the conventional steering device, when an abnormality is found in the steer-by-wire type steering system or when the engine is stopped, the steering gear and the steering shaft connected to the steering wheel are mechanically connected by an electromagnetic clutch or the like. Therefore, the merit of the steer-by-wire system that the steering shaft connected to the steering gear is unnecessary is lost.

  Therefore, a configuration in which an electromagnetic clutch is added to a configuration similar to a general mechanically coupled steering device is required, and a mounting space similar to that of a general mechanically coupled steering device is required.

  Therefore, the present invention was devised in order to improve the above-described adverse effects, and the object of the present invention is to connect the steering wheel and the toe angle of the wheel without mechanically connecting the steering wheel and the steering gear. It is an object of the present invention to provide a steering device capable of preventing the positional deviation of the steering wheel.

  In order to achieve the above-described object, a vehicle steering apparatus in the first problem solving means is not connected to a rotation operation member, an actuator driven according to an operation amount of the rotation operation member, and the rotation operation member. In a vehicle steering apparatus including a wheel that is steered by driving only the actuator, a wheel toe angle detection unit is provided, and a rotation blocking unit that blocks rotation of the rotation operation member is provided.

  According to a second aspect of the present invention, there is provided a vehicle steering apparatus, wherein the rotation operation member includes a steering wheel, a steering shaft connected to a central portion of the steering wheel, and the steering shaft rotatably held. The rotation preventing member is an electromagnetic brake, one end of the electromagnetic brake is connected to the shaft, and the other end is connected to the holding member.

  According to a third aspect of the present invention, there is provided a vehicle steering apparatus, wherein the rotation operation member includes a steering wheel, a steering shaft connected to a central portion of the steering wheel, and the steering shaft rotatably held. And an operation actuator that applies torque to the steering shaft, and the actuator includes a rotation preventing member.

  According to a fourth problem solving means, in the vehicle steering system according to the third field solving means, the shaft of the actuator and the steering shaft are connected by a gear mechanism, the rotation preventing member is an electromagnetic brake, and one end of the electromagnetic brake is connected. The actuator is connected to a shaft, and the other end is connected to a holding member.

  5. The fifth problem solving means according to any one of the first to fourth problem solving means, further comprising a steering blocking means for blocking wheel steering when the ignition switch is off. The vehicle steering device according to any one of the above.

  According to the present invention, when the ignition switch of the vehicle is off, the steered wheels are locked. Therefore, the position shift between the steered wheel and the toe angle of the wheel is prevented. And even if the ignition switch is turned on from the locked state of the steering wheel, the wheel is steered according to the steering angle operation, so that the positional deviation between the steering wheel and the toe angle of the wheel is prevented. The

  Therefore, it is possible to prevent the positional deviation between the steering wheel and the toe angle of the wheel without mechanically connecting the steering wheel and the steering gear. For example, when the steering wheel is fully turned, Even when the maximum toe angle is not taken or when the steering wheel is not fully cut, it is possible to prevent a problem that the wheel takes the maximum toe angle, that is, normal steering wheel operation is possible.

  In addition, since the positional deviation between the steering wheel and the toe angle of the wheel is prevented, the mechanical connection between the steering wheel and the steering gear for preventing the positional deviation is unnecessary, so the number of parts can be reduced, and It becomes possible to save the space of the steering device.

  Furthermore, since the steering wheel is locked when the ignition switch is in the off state, the vehicle is not damaged by theft of the vehicle.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a diagram conceptually showing a vehicle steering apparatus in an embodiment of the present invention. FIG. 2 is a cross-sectional view of the rotation operation member of the steering device according to the embodiment. FIG. 3 is a longitudinal sectional view of the rotation preventing means in the embodiment. FIG. 4 is a diagram conceptually illustrating a vehicle steering apparatus in a modification of the embodiment.

  As shown in FIG. 1, a vehicle steering apparatus according to an embodiment includes a rotation operation member C, an actuator A, a rack R driven by the actuator A, and tie rods 8 and knuckle arms 9 at both ends of the rack R. And the electromagnetic brake B as rotation preventing means.

  Hereinafter, the rotation operation member C will be described in detail. As shown in FIGS. 1 to 3, the rotation operation member C can freely rotate the steering wheel SW, the steering shaft S connected to the center portion of the steering wheel SW, and the steering shaft S. The holding member H for holding and the motor 10 as an operation actuator for applying torque to the steering shaft S are configured. Specifically, the steering shaft S is formed in a rod shape, a steering wheel SW is connected to one end, and a gear 11 is fitted to the other end as shown in FIG. As shown, the holding member H is rotatably held via ball bearings 30 and 30. The gear 11 is meshed with a worm gear 12. The worm gear 12 is rotatably supported by a holding member H via ball bearings 13 and 14, and one end of the worm gear 12 is connected to the holding member H. It is connected to the shaft 10a of the motor 10 which is a fixed operating actuator. Therefore, the operation speed of the steering wheel SW is increased by the combination of the gear 11 and the worm gear 12 and transmitted to the motor 10. The motor 10 is connected to the controller 15 and is driven by a command from the controller 15. Although the motor 10 is not specifically illustrated, if it is a brushless motor, the motor 10 is attached to the shaft 10a rotatably inserted into the frame, a coil wound around a core attached to the frame, and the shaft 10a. It comprises a plurality of magnets, and the magnets are provided so as to face the coil and the core. For example, a motor with a DC brush or an AC motor can be used as the motor 10 in addition to the brushless motor.

  Further, the encoder 20 is connected to the other end of the worm gear 12. The encoder 20 is connected to a light source 21 fixed in a sensor case 17 attached to the holding member H, an optical sensor 22 opposed to the light source, a processing circuit (not shown), and an end of the worm gear 12. A shaft 23 rotatably supported via a ball bearing 19 at 17, and a circular plate provided with a light-transmitting region and a light-shielding region in a circumferential portion facing the light source fixed to the outer periphery of the lower end of the shaft 23 in FIG. 24, and the disc 24 is located in the gap between the light source 21 and the optical sensor 22. When the steering shaft S rotates, the optical sensor 22 of the encoder 20 rotates when the disk 24 rotates via the gear 11 and the worm gear 12, and outputs a circle when receiving light that has passed through the light-transmitting region of the disk 24. It is connected to the controller 15 so that an electrical signal indicating the rotational position of the plate 24 can be transmitted. In the above description, the encoder 20 is provided. However, when the motor 10 is a brushless motor, a sensor capable of detecting the rotational position of the shaft such as a hall element or a resolver is provided, and therefore the encoder 20 is omitted. As an alternative, the above-described sensor may serve the role of the encoder 20, and a known sensor that detects the rotation angle or rotation speed of the operation shaft S or the operation wheel SW may be used instead of the encoder 20.

  Further, as shown in FIG. 3, the steering shaft S is connected to an electromagnetic brake B serving as a rotation preventing means fixed to the lower end of the holding member H in FIG. The electromagnetic brake B includes an armature 40 to which the steering shaft S is connected and an electromagnet 41 fixed to the holding member H side. Specifically, the steering shaft S includes an annular leaf spring 44. On the other hand, the electromagnet 41 connected to the hub 45 that supports the armature 40 and fixed to the holding member H is formed on the coil 42, the iron core 43 in which the coil 42 is installed, and the surface facing the armature 40. When an electric current is applied to the coil 42, the armature 40 is attracted to the electromagnet 41 against the spring force of the leaf spring 44 and comes into contact with the friction plate 46, whereby the steering shaft S is It cannot rotate with respect to the holding member H. When the coil 42 is deenergized, the armature 40 is separated from the electromagnet 41 by the restoring force of the leaf spring 44, so that the steering shaft S can freely rotate with respect to the holding member H. The coil 42 is connected to the power source of the vehicle so that it is energized when the ignition switch of the vehicle is off, and the coil 42 is disconnected when the ignition switch is on. Note that the mounting position of the electromagnetic brake B serving as the rotation blocking means is not limited to the end portion of the steering shaft S as long as the rotation of the steering wheel SW can be blocked, and as shown in FIG. It does not matter if it is provided in between.

  Subsequently, the actuator A is configured as a brushless motor, for example, similarly to the operation actuator. Specifically, although not shown, the shaft A1 is rotatably inserted into the frame, and is attached to the frame. The coil is composed of a coil wound around a core and a plurality of magnets attached to the shaft A1, and the magnet is provided so as to face the coil and the core. The coil of the actuator A is also connected to the controller 15. Although the actuator A has been described as a brushless motor, other motors such as a DC brush motor and an AC motor can be used. Although not shown, the shaft A1 is provided with a resolver 70 as a wheel toe angle detecting means so that the rotation angle of the shaft A1 can be detected, and the resolver 70 is connected to the controller 15.

  Further, although not shown, a worm gear is attached to the shaft A1 of the actuator A. The worm gear meshes with a gear (not shown), and a pinion gear 50 having the same shaft as the gear is provided. That is, the shaft A1 is connected to the pinion gear 50 via the worm gear and the gear. Therefore, the rotational speed of the actuator A is decelerated and transmitted to the pinion gear 50, and the pinion gear 50 meshes with a rack R that is slidably attached to the vehicle. That is, when the actuator A is driven, the rack R can move in the left-right direction in FIG. 1, and both ends of the rack R are connected to the tie rods 8, and the ends of the tie rods 8 are connected via the knuckle arms 9. Are connected to wheels W, W. Therefore, when the rack R is moved with respect to the vehicle as described above, the wheels W and W are configured to be steered at the same steering angle, which is configured as a so-called rack and pinion type steering gear. In the above description, the steering gear is a rack and pinion type, but it may be a ball screw type, and the link mechanism between the wheels W and W and the rack R is a so-called rack and pinion type in the present embodiment. However, other known link mechanisms such as a center arm type and a cross link type may be used. Further, each wheel may be directly driven by an actuator without using a link mechanism.

Further, the controller 15 is connected to the encoder 20, the motor 10, the actuator A, and the rotational position detection means of the actuator A, and is connected to a vehicle speed sensor 60 for detecting the traveling speed of the vehicle. It is connected to the. The controller 15 only needs to be able to receive signals from the encoder 20, the rotational position detecting means, the vehicle speed sensor 60, and the resolver 70, and to output a current necessary for driving the motor 10 and the actuator A. Specifically, although not shown as hardware, an amplifier for amplifying signals from the encoder 20, the vehicle speed sensor 60, and the resolver 70, a converter for converting an analog signal into a digital signal, and low and high frequency components A computer system comprising a CPU, a storage device such as a ROM, a RAM, a crystal oscillator, and a bus line connecting these, and a drive circuit for driving the motor 10 and the actuator A. And actuator A drive control Control signal output procedure required processing steps can be a well known system which allowed to pre-stored in the ROM or other storage device as a program. In the case of the motor 10 and the actuator A as a brushless motor, the drive circuit includes, for example, a PWM circuit connected to a voltage source, a base drive circuit connected to the PWM circuit, and a transistor inverter connected to the base drive circuit In addition, a well-known device composed of a rotating logic to which a hall element or the like is connected can be used, and another device that can adjust the amount of current according to the type of the motor can be used. Then, when the steering wheel SW is operated by the driver, the controller 15 controls and drives the actuator A to realize the steering angle and the steering angular velocity corresponding to the operation amount and the operation speed detected by the encoder 20. The wheels W and W are steered by the steering angle. Specifically, the controller 15 calculates the steering angle according to the operation amount or extracts the steering angle according to the operation amount from the control map, and at the same time changes the wheel toe angle detected by the resolver 70 as the wheel toe angle detection means. Judging from the amount, the actuator A is driven and controlled so that the wheels W are steered by the steering angle at the corresponding steering speed. In the above control, the wheel toe angle is in a neutral state and the steering wheel SW in that state.
Is stored in advance in the storage device of the controller 15, and the subsequent operation amount of the steering wheel SW and the change amount of the toe angle of the wheel are detected to determine the absolute position of the steering wheel SW and the absolute angle of the wheel toe angle. It is good to let the controller 15 know.

  At this time, the motor 10 is driven to apply a predetermined torque as a steering reaction force to the steering wheel SW from the vehicle speed. By continuously performing the above-described series of controls, the steering wheel SW can be steered even if the steering wheel SW is not mechanically connected to the steering gear, and the driver can reduce the vehicle speed by the steering reaction force loaded on the steering wheel SW. It is possible to obtain a natural steering feeling according to the vehicle. As described above, the wheel toe angle detection means is the resolver 70 attached to the shaft A1 of the actuator A. However, for example, a potentiometer or a stroke sensor that can detect the position of the rack R may be used. A potentiometer or the like may be attached to the fulcrum of the wheel to directly detect the actual toe angle of the wheel.

  When the ignition switch of the vehicle is off, a current is supplied to the electromagnet 41 of the electromagnetic brake B. Then, the armature 40 is attracted to the electromagnet 41, the steering shaft S is prevented from rotating with respect to the holding member H, and the steering wheel SW is locked. Therefore, immediately before the locked state, that is, when the ignition switch of the vehicle is on, the positions of the steering wheel SW and the wheels W and W are matched by the control of the controller 15 and the ignition switch is turned off. In other words, since the steering wheel SW is locked at the same time as the controller 15 is turned off, the misalignment between the steering wheel SW and the toe angles of the wheels W and W is prevented when the ignition switch is off. Even if the ignition switch is turned on from the locked state of the steering wheel SW, the steering wheel SW and the wheel W are now steered by the controller 15 according to the operation of the steering wheel SW by the controller 15. , W is prevented from being displaced from the toe angle.

  Therefore, it is possible to prevent the positional deviation between the steering wheel and the toe angle of the wheel without mechanically connecting the steering wheel and the steering gear. For example, when the steering wheel is fully turned, Even when the maximum toe angle is not taken or when the steering wheel is not fully cut, it is possible to prevent a problem that the wheel takes the maximum toe angle, that is, normal steering wheel operation is possible.

  Further, even if the ignition switch is turned off and the controller 15 is cut off, the displacement between the steering wheel SW and the toe angles of the wheels W, W is prevented. Since mechanical connection with the steering gear is not necessary, it is possible to reduce the number of parts and to save the space of the steering device.

  Furthermore, since the steering wheel SW is locked when the ignition switch is in the off state, the vehicle is not damaged by theft of the vehicle.

  Further, in the state where the ignition switch is turned on, that is, in the vehicle running state, the electromagnetic brake B is not supplied with current, so that the electromagnetic brake B cannot be energized for some reason. However, since only the free state in which the steered wheels SW can be freely operated is maintained, there is no fear of causing a situation in which steering becomes impossible while the vehicle is running.

  In the present embodiment, the electromagnetic brake B is attached to the steering shaft S. However, even if the electromagnetic brake is attached to the shaft 10a of the motor 10 and the ignition switch is off, the shaft 10a is locked. Good. Also by doing so, the steering shaft S is locked, so that the same operation and effect can be achieved.

  Next, a modification of the embodiment shown in FIG. 4 will be described. In the vehicle steering apparatus according to this modification, an electromagnetic brake B serving as a steering blocking means is provided on the shaft A1 of the actuator A of the vehicle steering apparatus according to the above-described embodiment. In this modification, when the ignition switch is turned off, not only the steering wheel SW is locked, but also the actuator A is locked, and the wheels W and W are also locked.

  Accordingly, the same effect as that of the above embodiment can be obtained, and at the same time, the wheels W and W are also locked. Therefore, even when an external force is applied to the wheels W and W, the steering wheel SW and the wheel W , W and a toe angle do not occur, so that the effect of preventing the misalignment between the steered wheel SW and the toe angles of the wheels W, W is enhanced.

  In each of the above-described embodiments, the electromagnetic brake is energized when the ignition switch is turned off. However, an electromagnetic brake that is locked when the power is cut off may be employed. Further, rotation prevention means other than the electromagnetic brake may be employed.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

1 is a diagram conceptually showing a vehicle steering apparatus in an embodiment of the present invention. It is sectional drawing of the rotation operation member of the steering device in one embodiment. It is a longitudinal cross-sectional view of the rotation prevention means in one embodiment. It is a figure which shows notionally the steering apparatus of the vehicle in the modification of one Embodiment.

Explanation of symbols

8 Tie rod 9 Knuckle arm 10 Actuator motor 10a Shaft 11 Gear 12 Worm gear 13, 14, 19 Ball bearing 15 Controller 17 Sensor case 20 Encoder 21 Light source 22 Optical sensor 23 Shaft 24 Disk 30 Ball bearing 40 Armature 41 Electromagnet 44 Plate spring 45 Hub 42 Coil 43 Iron core 46 Friction plate 50 Pinion gear 60 Vehicle speed sensor 70 Resolver A Actuator A1 Shaft B Electromagnetic brake C Rotating operation member H Holding member R Rack S Steering shaft SW Steering wheel W Wheel

Claims (5)

In a vehicle steering apparatus comprising: a rotation operation member; an actuator driven in accordance with an operation amount of the rotation operation member; and a wheel steered by driving only the actuator without being connected to the rotation operation member. A vehicle steering apparatus comprising a toe angle detecting means, and provided with a rotation preventing means for preventing rotation of a rotation operation member when an ignition switch is in an OFF state. The rotation operation member includes a steering wheel, a steering shaft connected to a central portion of the steering wheel, and a holding member that rotatably holds the steering shaft. The rotation prevention member is an electromagnetic brake. The vehicle steering apparatus according to claim 1, wherein one end is connected to a shaft and the other end is connected to a holding member. The rotation operation member includes a steering wheel, a steering shaft coupled to a central portion of the steering wheel, a holding member that rotatably holds the steering shaft, and an operation actuator that applies torque to the steering shaft. The vehicle steering apparatus according to claim 1, further comprising a rotation preventing member. The shaft of the actuator and the steering shaft are connected by a gear mechanism, the rotation preventing member is an electromagnetic brake, one end of the electromagnetic brake is connected to the shaft of the actuator, and the other end is connected to a holding member. Item 4. The vehicle steering device according to Item 3. The vehicle steering apparatus according to any one of claims 1 to 4, further comprising steering prevention means for preventing steering of the wheel when the ignition switch is off.

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