JP2015101129A - Vehicle steering unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle steering unit which can be easily mounted in a vehicle and can continue assistance in steering even in an abnormal state.SOLUTION: A transmission-ratio varying device 14 includes: a speed change gear mechanism 34 including a motor for relatively rotating first and second members 30, 32; a first coupling part 40 for putting an input shaft 20 and the first member 30 into a coupled state or decoupled state; a second coupling part 42 for putting the first input shaft and an output shaft 30 into a coupled state or decoupled state; a third coupling part 44 for putting the first member 30 and a vehicular body 45 into a coupled state or decoupled state. In a normal state, the input shaft 20 and first member 30 are put into a coupled state by the first coupling part 40, and the transmission-ratio varying device 14 makes a transmission ratio of the input shaft 20 and output shaft 22 variable. In an abnormal state, the input shaft 20 and output shaft 22 are put into a coupled state by the second coupling part 42, and the first member 30 and vehicular body 45 are put into a coupled state by the third coupling part 44, and a motor provides steering torque.

Description

  The present invention relates to a vehicle steering apparatus including transmission ratio variable means.

  The vehicle steering device is provided with an EPS (Electric Power Steering) device for assisting the driver's steering, and a transmission ratio variable device for varying the transmission ratio of the input side steering torque and the output side steering torque. It is done. As a result, smooth and comfortable steering of the driver is achieved.

  The steering device described in Patent Document 1 includes an input shaft to which a steering handle is connected, an output shaft connected to a rack shaft via a rack and pinion gear device, and a transmission that connects the input shaft and the output shaft. A variable ratio mechanism. This variable transmission ratio mechanism has a gear mechanism that connects the input shaft and the output shaft, and a servo motor that drives the gear mechanism, and is driven by the servo motor to transmit the rotation amount between the input shaft and the output shaft. The ratio changes.

  The vehicle steering control device described in Patent Literature 2 includes a transmission ratio variable device provided on a steering shaft, and an electric power steering device on the rack and pinion side. This transmission ratio variable device has an electric motor as a rotary actuator and a reduction gear mechanism. The electric motor of the transmission ratio variable device has a stator fixed to the vehicle body and a rotor that can rotate relative to the stator.

JP 11-310147 A JP 2008-273419 A

  When an abnormal state occurs in the electric power steering apparatus, the operation feeling of the driver may change when the input / output shaft is coupled to the manual mode in the electric power steering apparatus. Therefore, there is a method of continuing steering assist with another motor in an abnormal state of the electric power steering device. Installing a new motor on the steering shaft is subject to space constraints.

  The transmission ratio variable device of Patent Document 1 is provided with a motor. However, even if the motor is driven, it operates so as to change the transmission ratio of the gear device, so that it does not assist steering.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a vehicle steering apparatus capable of continuing steering assist even in an abnormal state.

  In order to solve the above-described problems, a vehicle steering apparatus according to an aspect of the present invention provides a transmission that varies a transmission ratio between an input shaft that is rotated by a steering input and an output shaft that outputs rotation of a turning angle. A variable ratio device. The transmission ratio variable device includes a first member that supports the input shaft and the output shaft, a second member that rotates relative to the first member and is connected to the output shaft, and a transmission ratio between the steering angle and the turning angle. A variable speed gear mechanism, first connecting means for connecting or disengaging the input shaft and the first member, and second connecting means for connecting or disengaging the input shaft and the output shaft. And a third connecting means for bringing the first member and the vehicle body into a connected state or a disconnected state. The transmission gear mechanism includes a motor that relatively rotates the first member and the second member. In the normal state, the input shaft and the first member are connected by the first connecting means, and the transmission ratio variable device makes the transmission ratio of the input shaft and the output shaft variable, and in the abnormal state, the second connecting means The input shaft and the output shaft are connected, the first member and the vehicle body are connected by the third connecting means, and steering torque is applied by the motor.

  According to this aspect, while functioning as a transmission ratio variable means in the normal state, torque can be applied by the motor instead of the electric power steering device in the abnormal state, and the driver's operation can be assisted. Thereby, the driver's steering can be assisted without separately providing an electric power steering device for the abnormal state.

  According to the present invention, steering assistance can be continued in an abnormal state in a vehicle steering apparatus.

It is a perspective view for demonstrating the outline of a structure of a vehicle steering device. It is a figure for demonstrating another vehicle steering device. It is a figure for demonstrating the transmission ratio variable apparatus of embodiment.

  FIG. 1 is a perspective view for explaining an outline of the configuration of the vehicle steering apparatus 10. The vehicle steering device 10 includes a steering wheel 12, a steering shaft 13, a transmission ratio variable device 14, a steering angle sensor 15, a rack gear 18 with EPS, and a dashboard 24.

  The steering wheel 12 is provided in the vehicle compartment and is turned by the driver. One end of the steering shaft 13 is connected to the steering wheel 12 so as to rotate together with the steering wheel 12, and functions as a rotating shaft that transmits the rotation of the steering wheel 12 to the transmission ratio variable device 14.

  The steering shaft 13 includes an input shaft 20 that connects the steering wheel 12 and the transmission ratio variable device 14, and an output shaft 22 that connects the transmission ratio variable device 14 and the rack gear 18 with EPS.

  The transmission ratio variable device 14 changes the rotation angle input from the input shaft 20 and transmits it to the output shaft 22. The transmission ratio variable device 14 varies the transmission ratio between the steering angle input to the input shaft 20 and the turning angle given to the wheel-side steering device. For example, the transmission ratio variable device 14 shifts the input from the input shaft 20 and outputs it to the output shaft 22. The transmission ratio variable device 14 includes a motor and a planetary gear mechanism as a transmission means.

  The rack gear 18 with EPS is connected to a steering gear box that converts the rotation of the steering wheel 12 into the steering motion of the wheel. The rack gear 18 with EPS and the steered gear box have rack and pinion gears, and the rotation of the steering wheel 12 is converted into axial movement of the steered shaft. The steered gear box is connected to a front wheel or a rear wheel to steer the wheel.

  The EPS-equipped rack gear 18 and the transmission ratio variable device 14 are controlled based on the output result of the steering angle sensor 15 by a control device (not shown). In addition to the rudder angle sensor 15, a torque sensor or an angular velocity sensor may be provided on the steering shaft 13.

  The vehicle steering device 10 can be roughly divided into a vehicle compartment side and an engine space side via the dashboard 24. The steering wheel 12 is provided on the vehicle interior side, and the transmission ratio variable device 14 and the rack gear 18 with EPS are provided on the engine space side.

  FIG. 2 is a diagram for explaining the vehicle steering device 100 of the comparative technique. The vehicle steering device 100 is a technique to be compared with the vehicle steering device 10. The vehicle steering apparatus 100 includes a steering wheel 12, a steering shaft 13, a rudder angle sensor 15, a column EPS motor 16, and a connecting portion 25 with a bearing. The bearing-equipped connecting portion 25 is a cover provided with a bearing that rotatably supports the steering shaft 13, and is connected to, for example, a rack and pinion gear cover.

  The column EPS motor 16 is an EPS device that applies auxiliary torque in accordance with steering. Since the column EPS motor 16 has a drive source such as an electric motor, the structure becomes large, and it is necessary to secure a sufficient mounting space.

  A universal joint 17 is provided on the steering shaft 13 on the passenger compartment side. A steering angle sensor 15 and a column EPS motor 16 are provided between the steering wheel 12 and the universal joint 17, and there is a large space restriction for mounting other mechanisms (motors). It is difficult in terms of space to mount other mechanisms (motors) from the universal joint 17 to the connecting portion 25 with bearing. That is, it is difficult to newly provide an abnormal EPS motor in the portion 13a around the universal joint 17 of the steering shaft 13.

  The vehicle steering device 10 according to the embodiment normally assists the steering with the rack gear 18 with EPS, and makes the transmission ratio variable device 14 function as an EPS device when abnormal, so that the large column EPS motor 16 can be eliminated. Vehicle mountability can be improved.

  FIG. 3 is a diagram for explaining the transmission ratio variable device 14 according to the embodiment. The transmission ratio variable device 14 includes a first member 30, a second member 32, a transmission gear mechanism 34, a first bearing portion 36, a second bearing portion 38, a first connecting portion 40, a second connecting portion 42, and a third connecting portion. 44. Further, the transmission ratio variable device 14 is connected to a control device (not shown) and its drive is controlled.

  The first member 30 is formed in a box shape and houses the second member 32 and the transmission gear mechanism 34. The first member 30 is connected to the vehicle body 45 via the third connection portion 44, and the first member 30 is fixed to the vehicle body 45 in the connected state.

  The first bearing portion 36 rotatably supports the input shaft 20. The second bearing portion 38 rotatably supports the output shaft 22. The input shaft 20 and the output shaft 22 are coaxial, and the first bearing portion 36 and the second bearing portion 38 are also coaxial.

  The second member 32 is provided to be rotatable relative to the first member 30 in the internal space of the first member 30. The second member 32 includes a disc-shaped disc portion 32a and a cylindrical cylindrical portion 32b that is connected to the tip of the disc portion 32a. One end of the second member 32 is connected to the output shaft 22, and the other end of the second member 32 is connected to the input shaft 20 via the second connecting portion 42.

  A plurality of transmission gear mechanisms 34 are provided on the disk portion 32 a of the second member 32. The transmission gear mechanism 34 has a planetary gear mechanism and functions as a transmission ratio variable means for changing the input / output ratio. The transmission gear mechanism 34 can adjust a transmission ratio that is an input / output ratio.

  The 1st connection part 40 makes the input shaft 20 and the 1st member 30 a connection state or a connection cancellation | release state. In the connected state, the input shaft 20 and the first member 30 are fixed and rotate integrally. In the disconnected state, the input shaft 20 is pivotally supported by the first bearing portion 36 of the first member 30 and rotates independently of the first member 30.

  The 2nd connection part 42 makes the input shaft 20 and the output shaft 22 a connection state or a connection cancellation | release state. In the connected state, the input shaft 20 and the output shaft 22 rotate integrally, and in the disconnected state, the input shaft 20 and the output shaft 22 rotate independently and rotate relative to each other.

  The 3rd connection part 44 makes the 1st member 30 and the vehicle body 45 a connection state or a connection cancellation | release state. In the connected state, the first member 30 is fixed to the vehicle body 45, and the first member 30 is unable to rotate. In the disconnected state, the first member 30 can be rotated without being bound to the vehicle body 45.

  The first member 30 and the second member 32 are rotatable relative to each other, and function as an inner rotor type motor that rotates relative to a drive current supplied from a drive circuit of a control device (not shown). The transmission ratio variable device 14 is further provided with a drive mechanism (not shown) such as a core, a coil, and a magnet. The control device controls the connected state or the disconnected state of the first connecting part 40, the second connecting part 42, and the third connecting part 44, respectively.

  The 1st connection part 40, the 2nd connection part 42, and the 3rd connection part 44 are lock mechanisms. For example, the first connecting portion 40 has a locking claw that is hooked in a recess formed on the outer peripheral surface of the input shaft 20, and is brought into a connected state by hooking the locking claw on the recess of the input shaft 20. Similarly to the first connection portion 40, the third connection portion 44 also has a locking claw that is hooked in a recess formed on the outer peripheral surface of the first member 30. The second connecting portion 42 has an input side tooth portion formed at the tip end of the input shaft 20 and an output side tooth portion formed at the tip end of the output shaft 22, and the input side tooth portion and the output side tooth portion are It has a clutch structure that meshes. The operation of the transmission ratio variable device 14 will be described.

  The control device determines that the vehicle steering device 10 is in an abnormal state when it detects a predetermined abnormality, that is, when it does not satisfy a predetermined abnormality criterion. Further, the control device determines that the vehicle steering device 10 is in the normal state when it does not detect a predetermined abnormality. The case where the predetermined abnormality is not detected is a case where the predetermined abnormality is not detected. The controller may determine that the EPS rack gear 18 is abnormal when there is an abnormality.

  In a normal state, that is, when there is no abnormality in the vehicle steering device 10, the first connecting portion 40 brings the input shaft 20 and the first member 30 into a connected state. In the normal state, the second connecting portion 42 brings the input shaft 20 and the output shaft 22 into a disconnected state, and the third connecting portion 44 puts the first member 30 and the vehicle body 45 into a disconnected state. In a normal state, the 1st connection part 40 is in a connection state, and the 2nd connection part 42 and the 3rd connection part 44 are in a connection cancellation | release state. Each connecting portion takes a connected state and a disconnected state according to a command signal from the control device.

  In a normal state, the EPS motor of the rack gear 18 functions as a torque applying unit, and applies a rotation of a turning angle based on a predetermined transmission ratio derived by the transmission ratio variable unit to the output shaft 22. The rotation of the input shaft 20 is transmitted to the first member 30, and the first member 30 rotates together with the first member 30 because it is not fixed to the vehicle body 45. The input shaft 20 and the output shaft 22 are in a disconnected state, and the input shaft 20 and the output shaft 22 rotate independently.

  That is, when a steering angle is input from the input shaft 20 to the transmission ratio variable device 14 in the normal state, the input shaft 20 and the first member 30 rotate idly, and the control device determines the transmission ratio based on the steering angle and the steering angular velocity. The EPS motor of the rack gear 18 gives a turning angle to the output shaft 22 based on the steering angle and the transmission ratio. Thereby, a driver | operator's steering can be made smooth.

  In the abnormal state, the first connecting portion 40 brings the input shaft 20 and the first member 30 into a disconnected state. In the abnormal state, the second connecting portion 42 connects the input shaft 20 and the output shaft 22, and the third connecting portion 44 connects the first member 30 and the vehicle body 45. That is, in the abnormal state, the first connecting part 40 is in a disconnected state, and the second connecting part 42 and the third connecting part 44 are in a connected state.

  In an abnormal state, the input shaft 20 and the output shaft 22 are connected by the second connecting means, and the first member 30 and the vehicle body 45 are connected by the third connecting means, and the first member 30 and the second member 32 are connected. A steering torque is applied to the output shaft 22 by the motor of the transmission ratio variable device 14 including As a result, the input shaft 20 and the output shaft 22 rotate together in a state where the first member 30 is fixed, that is, cannot rotate relative to each other, and the driver's steering is transmitted to the steering device even in an abnormal state. On the other hand, it is possible to assist steering by the motor of the transmission ratio variable device 14.

  According to this aspect, when the EPS device of the rack gear 18 with EPS is in an abnormal state, the transmission ratio variable device 14 can perform steering assist. As a result, the steering assist can be continued without separately providing an assist motor for use in an abnormal state, so that the mountability can be improved and the vehicle can be downsized.

  In the above, this invention was demonstrated based on each embodiment. It is to be understood by those skilled in the art that these embodiments are exemplifications, and various modifications can be made to each component and process combination, and such modifications are also within the scope of the present invention. Such modifications will be described below.

  DESCRIPTION OF SYMBOLS 10 Vehicle steering device, 12 Steering wheel, 13 Steering shaft, 14 Transmission ratio variable device, 15 Steering angle sensor, 16 Column EPS motor, 17 Universal joint, 18 Rack gear with EPS, 20 Input shaft, 22 Output shaft, 24 Dashboard, 30 1st member, 32 2nd member, 32a disk part, 32b cylindrical part, 34 transmission gear mechanism, 36 1st bearing part, 38 2nd bearing part, 40 1st connecting part, 42 2nd connecting part, 44 3rd 45 connecting parts.

Claims (1)

An input shaft that is rotated by a steering input;
A transmission ratio variable device that varies a transmission ratio between the input shaft and an output shaft that outputs rotation of a turning angle;
The transmission ratio variable device is:
A first member that pivotally supports the input shaft and the output shaft;
A second member that rotates relative to the first member and is coupled to the output shaft;
A transmission gear mechanism for changing a transmission ratio between a steering angle and the turning angle;
First connection means for bringing the input shaft and the first member into a connected state or a disconnected state;
Second connection means for bringing the input shaft and the output shaft into a connected state or a disconnected state;
And a third connecting means for bringing the first member and the vehicle body into a connected state or a disconnected state,
The transmission gear mechanism includes a motor that relatively rotates the first member and the second member;
In a normal state, the input shaft and the first member are connected by the first connecting means, and the transmission ratio variable device makes the transmission ratio of the input shaft and the output shaft variable,
In an abnormal state, the input shaft and the output shaft are connected by the second connecting means, the first member and the vehicle body are connected by the third connecting means, and steering torque is applied by the motor. A vehicle steering apparatus.

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