KR100707280B1 - Steer-by-wire type power steering apparatus for automotive vehicle - Google Patents

Abstract

The present invention relates to a steer-by-wire power assisted steering apparatus of an automobile.

According to an aspect of the present invention, there is provided a steering-by-wire steering apparatus for a vehicle including an input mechanism part for steering input of a driver and an output mechanism part for steering output to a wheel, wherein the input mechanism part is a steering wheel. A steering shaft connected to the steering shaft; A first sensor detecting a magnitude of a rotation angle of the steering shaft; A first electronic control device receiving an electrical signal from the first sensor; And a reaction force motor controlled by the first electronic control device, wherein the output mechanism unit comprises: a rack bar having both ends connected to the wheel; A drive motor for supplying auxiliary power to the rack bar; A motor position sensor for detecting a position of a motor shaft of the drive motor; And a second electronic control device configured to receive an electrical signal from the motor position sensor.

According to the present invention, when the calculated value of the difference between the two signals transmitted from the motor position sensor and the steering angle sensor to the electronic control device is greater than a specific value, the electronic control device performs a fail-safe function to maintain steering stability. It is effective to secure.

Steer-By-Wire, Fail-Safe, Steering

Description

Steer-By-Wire Type Power Steering Apparatus for Automotive Vehicle

1 is a configuration diagram showing an electric power assist steering device of a typical vehicle;

2 is a block diagram showing a steer-by-wire power assisted steering device of a vehicle according to the prior art;

3 is a block diagram showing a steer-by-wire power assisted steering apparatus of a vehicle according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

101: steering wheel 106: tie rod

107: knuckle arm 108: wheels

201: reaction motor 203: drive motor

301: steering shaft 303: first sensor

305: first electronic control device 310: input mechanism unit

311: rack bar 315: motor position sensor

317: pinion shaft 318: second sensor

319: second electronic control device 320: output mechanism unit

321: first reaction force gear 323: second reaction force gear

325: motor shaft

The present invention relates to a steer-by-wire power assisted steering apparatus of an automobile. More specifically, the electronic control device having a drive motor for supplying steering assistance power to the rack bar and calculating a difference between two signals respectively transmitted from the motor position sensor and the steering angle sensor to the electronic control device is greater than a specific value. Steering-by-wired power assisted steering of a vehicle to provide steering safety by providing a warning signal to the driver or controlling the drive of the reaction motor.

Generally, as a power assist steering device of a vehicle, a hydraulic power steering steering system using hydraulic pressure of a hydraulic pump has been used, but since the 1990s, an electric power steering steering system using an electric motor has been used. It is becoming more and more common.

Conventional hydraulic power assisted steering system consumes energy at all times regardless of whether the steering wheel is rotated by the hydraulic pump driven by the engine. When generated, a motor driven by electrical energy provides steering assistance power. Therefore, when the electric power assist steering device is used, it is possible to improve the energy efficiency of the vehicle compared to the hydraulic power assist steering device.

1 is a configuration diagram showing an electric power assisted steering apparatus of a general automobile, and FIG. 2 is a cross-sectional view showing a deceleration mechanism according to the prior art.

As shown in FIGS. 1 and 2, an electric power assisted steering device generally includes a steering power supply 100 that provides steering assistance power to the steering system 100 and steering system that extends from the steering wheel 101 to the wheels on both sides 108. 120).

The steering system 100 has one side connected to the steering wheel 101 to rotate together with the steering wheel 101 and the other side to the steering shaft 102 connected to the pinion shaft 104 via a pair of universal joints 103. It is configured to include). In addition, the pinion shaft 104 is connected to the rack bar 109 through the rack-pinion mechanism 105, and both ends of the rack bar 109 are connected to the wheels of the vehicle through the tie rod 106 and the knuckle arm 107. Is connected to 108.

The rack-pinion mechanism portion 105 is formed by engaging the pinion gear portion 111 formed on the pinion shaft 104 and the rack gear portion 112 formed on one side of the outer circumferential surface of the rack bar 109, so that the driver steers. When the wheel 101 is operated, torque is generated in the steering system 100, and the wheel 108 is steered through the rack-pinion mechanism 105 and the tie rod 106 by the generated torque.

The auxiliary power mechanism 120 senses torque applied to the steering wheel 101 by the driver and outputs an electrical signal proportional to the detected torque based on the electrical signal transmitted from the torque sensor 121 and the torque sensor 121. Electronic control unit (ECU) 123 for generating control signals, motor 130 for generating auxiliary power based on control signals transmitted from electronic control device 123, and auxiliary power generated in motor 130 It is configured to include a reduction mechanism 140 for transmitting to the steering shaft (102).

Therefore, in the electric power assisted steering device, the torque generated by the rotation of the steering wheel 101 is transmitted to the rack bar 109 via the rack-pinion mechanism 105, and the auxiliary generated in the motor 130 according to the generated torque. Power is delivered to the rack bar 109. That is, the torque generated from the steering system 100 and the auxiliary power generated from the motor 130 are combined to move the rack bar 109 in the axial direction.

However, in the conventional electric power assisted steering apparatus having such a structure, a steering shaft for steering input must mechanically connect the steering wheel and the pinion shaft. However, it is not easy to manufacture the steering device so that the steering shaft connects the steering wheel and the pinion shaft to avoid other parts of the vehicle.

Accordingly, in order to solve this problem, a steering-by-wire power assisted steering device of an automobile has been developed.

As shown in FIG. 2, the steer-by-wire power assisted steering device of the vehicle eliminates the mechanical connection between the steering wheel 101 and the wheel 108 of the vehicle.

In such a steer-by-wire type power assisted steering device, the driver feels a proper steering feeling by the reaction force motor 201 driven by the electronic control device 123 but rotating in a direction opposite to the rotation direction of the steering wheel 101. In addition, the pinion shaft 104 and the rack bar 109 are moved by the driving of the drive motor 203 which is also driven by the electronic control device 123 to operate the wheel 108.

However, in the case of the steering-by-wire power assisted steering device, since the steering angle sensor 205 of the steering wheel side senses the magnitude of the steering angle by the steering wheel operation of the driver, sufficient steering stability in case of failure of the steering angle sensor 205 or the like. There was a problem that was difficult to maintain.

Therefore, the present invention has been invented to solve the above problems, when the rack motor is provided with a drive motor and the value calculated by calculating the difference between the two signals respectively transmitted from the motor position sensor and the steering angle sensor to the electronic control device is greater than a specific value Its main purpose is to provide a steer-by-wire power assisted steering of an automobile in which the electronic control unit can fail-safe to ensure steering stability.

In order to achieve the above object, the present invention provides a steering-by-wire type steering apparatus for a vehicle including an input mechanism unit for steering input of a driver and an output mechanism unit for steering output to a wheel. The mechanism unit includes a steering shaft connected to the steering wheel; A first sensor for sensing a magnitude of a rotation angle of a steering shaft; A first electronic control device receiving an electrical signal from the first sensor; And a reaction force motor controlled by the first electronic control apparatus, wherein the output mechanism unit comprises: a rack bar having both ends connected to the wheels; A drive motor for supplying auxiliary power to the rack bar; A motor position sensor for detecting a position of the motor shaft of the drive motor; And a second electronic control device configured to receive an electrical signal from the motor position sensor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

3 is a block diagram showing a steer-by-wire power assisted steering apparatus of a vehicle according to a preferred embodiment of the present invention.

As shown in FIG. 3, the steering-by-wire type power assisted steering device of a vehicle according to the preferred embodiment of the present invention includes a steering shaft 301 connected to a steering wheel 101 and a rotation angle of a steering shaft 301. The reaction force motor 201 controlled by the first sensor 303, the first electronic control device 305 that receives an electrical signal from the first sensor 303, and the first electronic control device 305, which senses magnitude, The position of the motor shaft of the input mechanism unit 310 and the rack bar 311 connected to the wheels 108, the drive motor 203 for supplying auxiliary power to the rack bar 311, and the drive motor 203, which are included, The motor position sensor 315 to be detected, the rack bar 311 meshes with the pinion shaft 317 and the pinion shaft 317 rotates by a linear movement of the rack bar 311 senses the magnitude of the rotation angle The second electronic control field receives an electrical signal from the second sensor 318 and the motor position sensor 315 and the second sensor 319 It is configured by including an output mechanism (320) including 319.

The input mechanism 310 includes a steering shaft 301, a first sensor 303, a first electronic control device 305, and a reaction force motor 201 as a device for steering input of a driver.

The steering shaft 301 is connected to the steering wheel 101 at an upper end thereof, and rotates in the rotation direction of the steering wheel 101.

However, unlike the general steering device which is mechanically connected to the gear box at the bottom, the steering shaft 301 of the present invention is not mechanically connected to the pinion shaft 317 or the rack bar 311 at the bottom.

A first reaction force gear 321 is formed at a lower end of the steering shaft 301, and the first reaction force gear 321 meshes with a second reaction force gear 323 driven by the reaction force motor 201.

The first sensor 303 is a device for detecting the magnitude of the rotation angle of the steering shaft 301. After detecting the magnitude of the rotation angle of the steering shaft 301, the first sensor 303 controls an electrical signal proportional to the detected value. To device 305. As the first sensor 303, an absolute angle sensor may be used, or a relative angle sensor may be used.

The first electronic control apparatus 305 receives an electrical signal from the first sensor 303, transmits a control signal to the reaction force motor 201, and exchanges electrical signals with the second electronic control apparatus 319.

The reaction force motor 201 exerts a steering reaction force on the driver by driving to interfere with the rotation of the steering wheel 101.

That is, the second reaction force gear 323 is formed at the lower end of the motor shaft 325 of the reaction force motor 201, the motor shaft 325 rotates in the opposite direction to the rotation direction of the steering shaft 301, the driver Can feel the proper steering.

Meanwhile, the same effect may be obtained by adopting a worm wheel and a worm structure instead of the first reaction force gear 321 and the second reaction force gear 323 as necessary.

The operation principle of the first electronic control apparatus 305 and the reaction force motor 201 having such a configuration will be described below.

The first electronic control unit 305 receives an electrical signal from the second electronic control unit 319 and calculates a difference between the steering angle signal detected by the first sensor and the steering angle signal detected by the second sensor and based on the calculated value. The drive of the reaction force motor 201 is controlled.

That is, when the steering angle signal detected by the second sensor 319 is larger than the steering angle signal detected by the first sensor 303, the first electronic control apparatus 305 causes the reaction force motor 201 to produce a steering shaft ( 301) to apply a stronger steering reaction. In this case, the first electronic control apparatus 305 serves to improve steering stability by preventing a steering output that is too large compared to the steering input of the driver.

In the opposite case, that is, when the steering angle signal detected by the second sensor 319 is smaller than the steering angle signal detected by the first sensor 303, the first electronic control device 305 causes the reaction force motor 201 to cause the reaction force motor 201 to operate. By applying a weaker steering reaction force to the steering shaft 301, smooth steering is possible.

The output mechanism 320 is a device for manipulating the wheel 108 in the direction desired by the driver according to the driver's steering input. The rack bar 311, the drive motor 203, the motor position sensor 315, and the pinion shaft 317 ), A second sensor 318, and a second electronic control device 319.

The rack bar 311 is a device that receives the driving force from the drive motor 203 and changes the direction of the wheel 108 by linear movement in the axial direction.

The rack bar 311 is formed in a cylindrical shape, but both ends are connected to the wheel 108 through the tie rod 106 and the knuckle arm 107, and a rack gear 324 is formed at one side thereof. The rack gear 324 also meshes with the pinion gear 327 of the pinion shaft 317.

The drive motor 203 is formed coaxially with the rack bar 311 and transmits a driving force to the rack bar 311 through the ball screw part 329 surrounding the outer circumferential surface of the rack bar 311. In addition, the drive motor 203 is driven by receiving a control signal from the second electronic control device 319.

The motor position sensor 315 detects a position of a motor shaft (not shown) of the driving motor 203 and transmits a motor position signal proportional to the detected value to the second electronic control device 319.

The motor position sensor 315 transmits a motor position signal to the second electronic controller 319 every 0.14 degrees according to the rotation of the motor shaft (not shown) of the drive motor 203, and the second electronic controller 319. Calculates the rotation angle of the motor shaft (not shown) of the drive motor 203 through the motor position signal received from the motor position sensor 315, and calculates the rotation angle of the pinion shaft 317 from the calculated rotation angle. .

The pinion shaft 317 has a pinion gear 327 engaged with the rack gear 324 of the rack bar 311 at the lower end thereof, so that the pin bar 311 rotates when the rack bar 311 linearly moves.

The second sensor 318 detects the magnitude of the rotation angle of the pinion shaft 317 and transmits an electrical signal proportional to the detected value to the second electronic control device 319. An absolute angle sensor or a relative angle sensor may be used as the second sensor 318.

The second electronic control apparatus 319 exchanges signals with the first electronic control apparatus 305 while receiving electrical signals from the motor position sensor 315 and the second sensor 318, respectively, and transmits the signals to the driving motor 203. It is a device that controls the driving of the drive motor 203 by transmitting a control signal.

That is, the second electronic control device 319 calculates the magnitude of the rotation angle of the pinion shaft 317 from the motor position signal transmitted from the motor position sensor 315, while transmitting the calculated value and the second sensor 318 from the motor position signal 315. By comparing the magnitude of the rotation angle of the pinion shaft 317 calculated from the steering angle signal to be determined whether the motor position sensor 315 or the second sensor 318 is a failure.

In particular, in a fail situation in which a failure of the motor position sensor 315 or the second sensor 318 occurs, the second electronic control apparatus 319 may notify the driver by turning on a warning light formed on the driver's side. . At the same time or separately, the second electronic control apparatus 319 may send a signal to the first electronic control apparatus 305 to control the driving of the reaction force motor 201. In short, the second electronic controller 319 functions as a fail-safe function.

The above description is merely illustrative of the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential features of the present invention. Accordingly, the embodiments disclosed herein are not intended to limit the present invention but to describe the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

As described above, according to the present invention, when the value calculated from the difference between the two signals transmitted from the motor position sensor and the steering angle sensor to the electronic control device is greater than a specific value, the electronic control device fails-safe. Function to secure steering stability.

Claims (3)

In a steering-by-wire steering apparatus of an automobile comprising an input mechanism for steering input of a driver and an output mechanism for steering output to a wheel, The input mechanism unit, A steering shaft connected to the steering wheel; A first sensor detecting a magnitude of a rotation angle of the steering shaft; A first electronic control device receiving an electrical signal from the first sensor; And A reaction force motor controlled by the first electronic control apparatus, The output mechanism unit, A rack bar having both ends connected to the wheel; A drive motor for supplying auxiliary power to the rack bar; A motor position sensor for detecting a position of a motor shaft of the drive motor; And A second electronic control device receiving an electrical signal from the motor position sensor Steer-by-wire power assisted steering of a vehicle comprising a. The method of claim 1, A pinion shaft engaged with the rack bar and configured to rotate by the linear motion of the rack bar; And A second sensor that senses a magnitude of the rotation angle of the pinion shaft and transmits an electrical signal proportional to the detected value to the second electronic control apparatus Steer-by-wire power assisted steering apparatus for a vehicle, further comprising a. The method of claim 2, The second electronic control apparatus compares the electrical signal transmitted from the motor position sensor with the electrical signal transmitted from the second sensor, and generates a warning signal when the difference between the two values is greater than or equal to a specific value. Steer-by-wire power assisted steering of automobiles.

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