KR101047389B1 - Caleb Type Electric Power Steering Device - Google Patents

Abstract

The present invention relates to an electric power steering apparatus for generating a steering force necessary for steering a vehicle by driving a motor. The technical configuration of the present invention is a wheel for constituting the reducer in a reduction gear of a column type electric power steering apparatus. The grooves 250 and 260 are formed in the inner diameter of the shaft 25 and the outer diameter of the shaft 26 into which the wheel wheels 25 are press-fitted, and the needle pins 28 are press-fitted therebetween. The bottom of the shaft 26, the outer periphery of the fixed plate 29 is provided to support the wheel wheel 25 is a main point.

According to the present invention as described above, the driving force of the motor is transmitted to the wheel wheel 25 to drive the shaft 26 within a predetermined range of torque value, and in the range of excessive external force exceeding the torque value range, the shaft The wheel 25 on 26 is slipped by the needle pins 28 to prevent gear breakage and load on the motor.

C-EPS, Reducer, Wheel, Shaft, Needle Pin

Description

Color type electric power steering apparatus {Column type electric power steering apparatus}

1 is a cross-sectional view showing main parts of a conventional column type electric steering device.

Figure 2 is a cross-sectional view showing the main part of the column-type electric steering apparatus according to the present invention.

3 is an enlarged cross-sectional view of a reduction gear part of the steering apparatus;

4 is a cross-sectional view taken along the line A-A according to FIG.

<Code Description of Major Parts of Drawing>

23 ... drive motor

24,25 ... worm and worm wheel

26 ... shaft

28 ... needle pin

29.Fixed Edition

250,260 ... Home

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering device that generates a steering force necessary for steering a vehicle by driving a motor. In particular, the present invention relates to an electric power steering device that prevents damage of the reduction gear due to external force in a reduction gear for a column type electric steering device. The present invention relates to a column type electric power steering device for improving stability.

Generally, a power steering system is applied to a vehicle to ensure steering stability. Such a power steering device is a hydraulic power steering system (HPS) using a hydraulic pressure. Recently, unlike the conventional method of using hydraulic pressure, the rotational power of the motor makes it easier for the driver to steer and the installation of an environmentally friendly electric power steering system (EPS) is increasing.

Such an electric power steering device drives a motor in the ECU according to the driving conditions of the vehicle detected by the vehicle speed sensor and the steering torque sensor to provide a light and comfortable steering feeling at low speed, and a heavy steering feeling at high speed and a good direction. It provides stability and allows for quick steering in emergency situations, providing the driver with optimal steering conditions.

The electric power steering apparatus is classified into a column type (C-EPS) and a rack type (R-EPS) according to the installation position of the drive motor.

Here, the column type electric power steering apparatus (hereinafter, abbreviated as C-EPS) will be described with reference to the accompanying drawings.

Conventional C-EPS is based on a general rack-pinion type steering device, a steering angle sensor (not shown) for detecting the steering angle of the steering wheel, and the torsion generated in the steering column 10 torsion during steering The bar 11, the torque sensor 12 for detecting the torsion bar 11, the vehicle speed sensor (not shown) for detecting the traveling speed of the vehicle, and to assist the steering force on the axis of the steering column (10). It is configured to include a drive motor 13 to be installed so as to control the driving force of the drive motor by calculating the signal input from the steering angle sensor, the vehicle speed sensor and the torque sensor.

Here, a hollow shaft 16 is installed outside the torsion bar 11 below the steering column 10 to transmit the steering force, and the wheel wheel 15 is press-fitted to the upper outer circumference of the shaft 16. The gearbox is engaged with the worm gear 14 of the drive motor being throttled to achieve a speed reducer that reduces the output of the drive motor 13.

That is, the driving force of the driving motor 13 is transmitted to the shaft 16 through the reduction gear formed by the worm 14 and the worm wheel 15 engaged to assist the steering wheel steering force of the driver.

However, since the reducer of the conventional column type electric steering apparatus is configured to transmit torque by simply pressing the worm wheel 15 into the shaft 16 (see also a partial enlargement of FIG. 1), the wheel of the wheel is fitted to the shaft. If the external force is applied more than the value set by the pressure input, the gear of the reduction gear made of a special plastic material is usually broken, or if the tooth is not broken, the worm wheel 15 fitted to the shaft 16 is driven. There was a problem in that the driving force of (13) was lost while being displaced in the axial direction of the shaft and losing its function as a reducer.

The present invention has been made in view of the problems of the prior art as described above, and a needle pin is interposed between the inner diameter of the wheel wheel constituting the reducer of the column type electric steering device and the outer diameter of the shaft to which the wheel wheel is fitted. At the same time, by installing a fixed plate at the bottom of the wheel, it prevents damage to the gear reducer when excessive external force is applied, and prevents the worm wheel from falling off when the worm wheel is turned away from the shaft. The purpose is to provide a column type electric power steering device that can maintain the function of, thereby improving the stability of the system.

As a technical means for achieving the above object, the present invention provides a needle between the inner diameter of the wheel wheel constituting the speed reducer of the column type electric power steering device and the outer diameter of the shaft to which the wheel wheel is fitted into the needle. By inserting a pin to press-fit, the shaft outer peripheral portion of the lower wheel by inserting a fixed plate to provide a column type electric power steering device, characterized in that configured to support the wheel.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Briefly described with reference to the accompanying drawings, Figure 2 is a cross-sectional view showing the main portion of the column type electric steering apparatus according to the present invention, Figure 3 is an enlarged cross-sectional view showing a reduction gear portion of the steering apparatus, Figure 4 is It is sectional drawing which shows the cross section along AA line.

The column type electric power steering apparatus (hereinafter referred to as C-EPS) applied to the present invention includes a steering wheel, a steering column, a steering gear, and a steering linkage, and a conventional rack-pinion type. It is based on the steering system.

In the C-EPS, a steering angle sensor (not shown) for detecting a steering angle of a steering wheel is installed at one end of the steering column 20, and a torsion bar 21 and the torsion bar (21) inside the steering column 20. Torque sensor 22 for detecting the twist of the 21 is built-in, and a vehicle speed sensor (not shown) for detecting the traveling speed of the vehicle is provided.

In addition, the driving motor 23 for assisting the steering force is installed to be orthogonal to the axis of the shaft 26, and the worm 24 to transmit the driving force of the motor to the shaft 26 on the drive motor 23 side. ) And the worm wheel 25 are engaged to form a speed reducer.

In addition, the C-EPS includes an ECU which controls the driving force of the driving motor by calculating signals input from the steering angle sensor, the vehicle speed sensor, and the torque sensor described above.

In particular, according to the C-EPS configuration applied to the present invention, in the reduction gear of the above-described column type electric power steering apparatus, when excessive external force is applied to the reduction gear, it is a means for preventing the damage of the gear teeth constituting the reduction gear in advance. The needle pin 28 is introduced into the inner diameter of the worm wheel 25, which is a reduction gear, and the outer diameter of the shaft 26 to which the shock wheel 25 is fitted, thereby improving the stability of the system.

That is, as shown in Figs. 3 to 4, the groove 250 having a predetermined depth in the inner diameter of the reduction wheel 25, which is a reduction gear, and the outer diameter of the shaft 26 into which the wheel wheel 25 is press-fitted. 260 is formed, and the needle pin 28 is press-fitted between the wheel wheel 25 and the shaft 26 on which the grooves 250 and 260 are formed, and the push pin strength of the needle pin 28 is a torque in a predetermined range. In this case, the driving force of the motor can be transmitted to the shaft, and the wheel 25 on the shaft 26 can be circumferentially slipped by the needle pin 28 in the range of excessive external force exceeding the range of the torque. It is desirable to set.

On the other hand, as a means for preventing axial deviation of the wheel wheel 25 when the wheel wheel 25 slips on the sharp shape 26 due to the excessive external force as described above, The stationary plate 29 is provided to be configured to support the wheels 25.                     

In this case, the fixing plate 29 may be fixed to the shaft through caulking.

Therefore, the present invention having the above-described configuration, when excessive external force is applied to the reduction gear portion, that is, the torque set by the pressure input between the wheel wheel 25 and the shaft 26 via the needle pin 28. In the case of exceeding the teeth, the worm wheel 25 is slid in the circumferential direction on the shaft 26 by the driving force of the drive motor 13, thereby preventing the damage of the gear teeth and the overload of the motor.

At this time, the fixed wheel 29 is configured to support the lower end of the wheel wheel 25 so that when the worm wheel 25 slips as described above, the worm wheel 25 slides away from the shaft 26 in the axial direction. Things can also be prevented.

That is, according to the present invention, the driving force of the motor is transmitted to the wheel wheel 25 to drive the shaft 26 within a predetermined torque range, and in the range of excessive external force exceeding the torque value range. The wheel 25 on the shaft 26 is slipped by the needle pin 28 to prevent breakage and load of the gear.

As described above, according to the column type electric power steering apparatus of the present invention, a groove is formed in the inner diameter of the wheel, which constitutes the reducer, and the outer diameter of the shaft to which the wheel is fitted, and the needle pin is pressed therebetween, As the worm wheel on the shaft slips, it is possible to prevent breakage of the reducer teeth and overload of the motor. The fixing plate is configured to support the lower part of the wheel, so that the worm wheel is moved to the shaft when the worm wheel slips due to excessive external force. Slip in the axial direction can also be prevented to maintain the function of the reducer, thereby further improving the stability of the system.

While the invention has been shown and described with respect to specific embodiments thereof, it will be appreciated that various changes and modifications can be made in the art without departing from the spirit or scope of the invention as set forth in the following claims. It will be appreciated that those skilled in the art can easily know.

Claims (2)

A torsion bar installed in the steering column to which torsion occurs when steering, a torque sensor to detect the torsion bar's torsion, a vehicle speed sensor to detect the traveling speed of the vehicle, and a drive installed to assist the steering force on the axis of the steering column A column type comprising a motor, an reducer comprising a worm and a worm wheel so as to transmit the driving force of the motor to the steering column, and an ECU controlling the driving force of the driving motor by calculating signals input from the vehicle speed sensor and the torque sensor. In the electric power steering apparatus, Grooves 250 and 260 are formed in the inner diameter of the wheel wheel 25 constituting the reducer and the outer diameter of the shaft 26 into which the wheel wheel 25 is press-fitted so that the needle pin 28 is press-fitted therebetween. It is installed, the column type electric power steering device, characterized in that configured to support the wheel wheel 25 by providing a fixed plate 29 on the outer periphery of the shaft (26) below the wheel wheel (25). delete

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