KR20090088043A - Electrical power steering apparatus for vehicle equipped with integrated steering axis - Google Patents

Abstract

An electrical power steering apparatus for a vehicle including an integrated steering axis is provided to simplify an assembly process by integrating a bottom steering axis and a top steering axis. An electrical power steering apparatus for a vehicle including an integrated steering axis includes a steering axis(305), a torque sensor(125), a motor(130), an electronic control device, and a reducer(140). The steering axis delivers a steering force to an input axis(215) when an operator controls the steering axis. The torque sensor senses a torque applied to a torsion bar and the input axis by the steering axis, and outputs an electrical signal in proportion to a sensed torque. The electronic control device generates a control signal based on the electrical signal delivered from the torque sensor. The motor generates an auxiliary power based on the control signal delivered from the electronic control device. The reducer includes a worm and a worm wheel. The worm and the worm wheel deliver the auxiliary power generated in the motor to an output axis(220). The steering axis includes a steering wheel coupling part(315), a main body part(313), and an input axis coupling part(310). The steering wheel coupling part includes a serration part connected to the steering wheel.

Description

Electrical Power Steering Apparatus For Vehicle Equipped with Integrated Steering Axis

The present invention relates to an electric power assisted steering device of a motor vehicle.

More specifically, in the electric power assist steering apparatus of the automobile, the lower steering shaft is integrated with the upper steering shaft, thereby reducing the number of parts and the assembly process, and eliminating the serration processing and the plastic molding work of the lower steering shaft and the upper steering shaft. The present invention relates to an electric power assisted steering apparatus of an automobile having an integral steering shaft capable of eliminating noise after the endurance of the steering shaft coupling unit.

In general, the steering device of a vehicle allows the driver to freely change the direction of movement of the vehicle by turning the steering wheel. The steering wheel of the vehicle can arbitrarily change the center of rotation of the vehicle's front wheel so that the driver can move the vehicle in the desired direction. Auxiliary device.

In this steering system, a power steering system is used as an auxiliary power mechanism to relieve the driver's power, and such a power steering system uses hydraulic power of the engine to operate a hydraulic pump to assist steering power. There is a hydraulic power assist steering device using an electric power assist steering device using an electric motor.

The hydraulic power assist steering device senses the rotation of the steering wheel and receives the rotational force from the engine to operate the hydraulic pump and sends the hydraulic pressure to a drive such as a cylinder configured on the rack bar or steering shaft to assist the driver's steering power.

The electric power assisted steering device has a structure that detects the rotation of the steering wheel and is installed on the rack or steering shaft to operate a motor that assists the rotational movement so that the steering device operates smoothly. The electric power assisted steering device is largely rack driven. There are two types (R-EPS) and steering shaft drive type (C-EPS).

1 is a schematic diagram of a conventional electric power assisted steering device.

As shown in FIG. 1, the electric power assist steering device includes an auxiliary power mechanism 120 that provides steering assistance power to the steering system 100 and the steering system 100 that extend from the steering wheel 101 to both wheels 108. It is configured to include.

The steering system 100 has one side connected to the steering wheel 101 to rotate together with the steering wheel 101, the other side is connected to the pinion shaft 104 via a pair of universal joint 103, the steering shaft 102 It is configured to include).

In addition, the pinion shaft 104 is connected to the rack bar through the rack-pinion mechanism portion 105 and both ends of the rack bar are connected to the wheel 108 of the vehicle through the tie rod 106 and the knuckle arm 107. The rack-pinion mechanism 105 is formed by engaging the pinion gear 111 formed on the pinion shaft 104 with the rack gear 112 formed on one side of the outer circumferential surface of the rack bar, so that the driver operates the steering wheel 101. When the torque is generated in the steering system 100, the wheel 108 is steered through the rack-pinion mechanism 105 and the tie rod 106 by the torque.

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

2 is a partial cross-sectional view showing a steering shaft of a conventional electric power assisted steering device.

As shown in FIG. 2, the steering shaft of the conventional electric power assisted steering device includes a lower steering shaft 210 coupled with an input shaft 215 and a pin 225, and an upper steering shaft 205 coupled with the lower steering shaft 210. The upper steering shaft 205 is connected to a steering wheel (not shown), and the input shaft 215 is press-connected to the output shaft 220 to transmit steering force of the steering wheel. It is supposed to be done.

The lower end of the lower steering shaft 210 is inserted into the input shaft 215 and is coupled by the input shaft 215, the torsion bar 230, and the pin 225, and the upper end has a serration 235 formed on the outer circumferential surface of the upper steering shaft. It is inserted into the serration 235 formed on the inner circumferential surface of the 205 and is engaged with the upper steering shaft 205 by plastic molding of the serration 235.

Therefore, in order to combine the steering shaft, a serration 235 processing process is required on the outer circumferential surface of the lower steering shaft 210 and the inner circumferential surface of the upper steering shaft 205, respectively, and the lower steering shaft 210 of the lower steering shaft 210 is assembled again in the field. Since plastic molding was performed on the serration 235 and it was press-fitted into the serration 235 of the upper steering shaft 205, a lot of work processes and processing costs were generated, and noise was generated at the serration coupling part after durability. There was a problem.

In order to solve this problem, the present invention can reduce the number of parts and the assembly process by integrating the lower steering shaft with the upper steering shaft, and eliminate the serration processing and the plastic molding work of the lower steering shaft and the upper steering shaft. An object of the present invention is to provide an electric power assist steering apparatus for an automobile having an integrated steering shaft which can also reduce noise of the serration part.

In order to achieve the above object, the present invention provides a steering shaft that transmits a steering force to an input shaft when the driver operates a steering wheel, and a torque that senses torque applied to the input shaft and the torsion bar by the steering shaft and outputs an electrical signal proportional to the detected torque. The electronic control device which generates a control signal based on the sensor, the electric signal transmitted from the torque sensor, and the motor which generates auxiliary power based on the control signal transmitted from the electronic control device, and the auxiliary power generated by the motor are transmitted to the output shaft. In the electric power assisted steering apparatus for a vehicle configured to include a reducer having a worm and a worm wheel, the steering shaft is a steering wheel coupling portion provided with a serration portion connected to the steering wheel, the diameter is expanded and reduced The main body is formed, and the input shaft coupling portion coupled to the input shaft is formed integrally It provides an electric power assist steering device.

Hereinafter, 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 though they are shown in 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 partial cross-sectional view showing a steering shaft of the electric power assisted steering apparatus according to the present invention.

As shown in FIG. 3, the electric power assisted steering apparatus according to the present invention includes a steering shaft 305 which transmits a steering force to an input shaft 215 when the driver operates a steering wheel (not shown), and a steering shaft 305. Torque sensor 125 for detecting the torque applied to the input shaft 215 and the torsion bar 230 and outputs an electrical signal proportional to the detected torque, and a control signal based on the electrical signal transmitted from the torque sensor 125 The output shaft 220 receives the generated electronic controller (see 123 of FIG. 1), a motor (see 130 in FIG. 1) that generates auxiliary power based on a control signal transmitted from the electronic controller, and auxiliary power generated from the motor. It comprises a reducer 140 having a worm 141 and a worm wheel 143 for transmission.

Unlike the related art, the steering shaft 305 of the electric power assisted steering apparatus according to the present invention is integrally formed with the upper steering shaft (see 205 of FIG. 2) and the lower steering shaft (see 210 of FIG. 2).

That is, the steering shaft 305 of the electric power assisted steering apparatus according to the present invention is composed of a steering wheel coupling portion 315 and the main body portion 313 and the input shaft coupling portion 310, all of which are integrally formed have.

The steering wheel coupling part 315 is provided with a serration part 317 at an end thereof, and is coupled with a steering wheel (not shown) which rotates left and right when the driver steers.

The main body portion 313 is formed to extend from the steering wheel coupling portion 315, and the portion of which diameter is expanded and the portion having a constant diameter is formed to reinforce rigidity, and then the diameter thereof is reduced again so that the input shaft coupling portion 310 and It extends and is formed integrally.

 The input shaft coupling part 310 is inserted into the input shaft 215 to be coupled with the input shaft 215 and the torsion bar 230. At the ends of the input shaft coupling part 310, the input shaft 215 and the torsion bar are coupled to each other. The pin hole 320 penetrates the 230 and the input shaft coupling part 310, and is coupled by the pin 225 to transmit steering force by the steering wheel to the input shaft 215 and the torsion bar 230. .

The steering force transmitted to the input shaft 215 and the torsion bar 230 by the steering shaft 305 integrally formed as described above is a torque sensor 125 surrounding the torque of the torsion bar 230 and surrounding the input shaft 215 and the output shaft 220. ) Detects torque and outputs an electrical signal proportional to the detected torque and sends it to the electronic control device.

The electronic control device sends an appropriate control signal to the motor generating auxiliary power in accordance with the measured torque amount, so that the reducer 140 having the worm 141 and the worm wheel 143 outputs the auxiliary power generated from the motor. ) And the driver's steering power is transmitted.

According to the present invention having such a structure and shape, by reducing the number of parts and assembling process by integrating the lower steering shaft with the upper steering shaft, it is possible to eliminate the serration processing and plastic molding of the lower steering shaft and the upper steering shaft. In addition, there is an effect that can eliminate the noise of the steering shaft coupling after the endurance.

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 idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the same scope should be interpreted as being included in the scope of the present invention.

1 is a schematic diagram of a conventional electric power assisted steering device;

2 is a partial cross-sectional view showing a steering shaft of a conventional electric power assisted steering device;

3 is a partial cross-sectional view showing a steering shaft of the electric power assisted steering apparatus according to the present invention.

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

100: steering system 101: steering wheel

104: pinion shaft 105: rack-pinion mechanism

111: pinion gear 112: rack gear

120: auxiliary power mechanism 123: electronic control device

125: torque sensor 130: motor

140: reducer 205: upper steering shaft

210: lower steering shaft 215: input shaft

220: output shaft 225: pin

230: torsion bar 235: serration

305: steering shaft 310 of the present invention: input shaft coupling portion

315: steering wheel coupling 320: pinhole

Claims (2)

A steering shaft that transmits steering force to the input shaft when the steering wheel is operated by the driver, a torque sensor that senses the torque applied to the input shaft and the torsion bar by the steering shaft, and outputs an electrical signal proportional to the detected torque, and electricity transmitted from the torque sensor. An electronic control device that generates a control signal based on the signal, a motor that generates auxiliary power based on the control signal transmitted from the electronic control device, and a reducer having a worm and a worm wheel for transmitting auxiliary power generated from the motor to the output shaft. In the electric power assisted steering device for a vehicle configured to include, The steering shaft includes a steering wheel coupling part including a serration part connected to the steering wheel, a main body part formed by expanding and contracting diameters, and an input shaft coupling part coupled to the input shaft, wherein the electric power assisting unit is integrally formed. Steering system. The method of claim 1, The steering shaft is an electric power assisted steering device, characterized in that the pin shaft for coupling with the input shaft is formed through the input shaft coupling end, and is coupled by the input shaft and the torsion bar and the pin.

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