KR100434202B1 - Columm type electric power steering device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a column type electric power steering device, and is a means capable of intermittent driving force of a drive motor 13, and includes a conventional electromagnetic clutch with a tolerance ring (20). The number of components was simplified by replacing with.

That is, the drive shaft 16 and the worm shaft 17 of the drive motor 13 are connected by the spline 21, and the tolerance ring 20 is inserted between the drive shaft 16 and the spline 21 so that the entire steering system Not only can lower the installation cost, but also eliminate the noise generated by the electronic clutch.

Description

Column type electric power steering device {COLUMM TYPE ELECTRIC POWER STEERING DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a column type electric power steering device. More particularly, the present invention relates to a means capable of intermittent driving force of a driving motor, and replaces a conventional electromagnetic clutch with a tolerance ring. The present invention relates to a column-type electric power steering device with a simplified number of components.

In general, the speed-sensitive power steering device adjusts the steering power of the steering wheel according to the speed of the vehicle.If the speed of the vehicle increases, the steering power of the steering wheel is heavy, and if the speed of the vehicle decreases, the steering power of the steering wheel is lightened. It is a device that gives a sense of stability when driving at high speeds, and allows the steering wheel to be operated with a small force at low speeds such as during parking.

The vehicle speed-sensitive power steering method is largely divided into hydraulic and electric motors. The electric power steering method is also classified into a rack method and a column method according to the installation position of the drive motor.

A conventional column type electric power steering device (columm type electric power steering device; hereinafter abbreviated as C-EPS) will be described with reference to FIGS. 1 and 2 as follows.

Conventional C-EPS is based on a general rack-pinion type steering device, a steering angle sensor for detecting a steering angle of a steering wheel, and a torsion bar (11) installed in the steering column (10) to which torsion occurs during steering. ), A torque sensor 12 for detecting the torsion of the torsion bar 11, a vehicle speed sensor for detecting the traveling speed of the vehicle, and a driving motor installed to assist steering on the axis of the steering column 10. And an electronic control unit which processes signals input from the steering angle sensor, the vehicle speed sensor, and the torque sensor 12 to control the driving force of the drive motor 13.

On the other hand, the driving force of the drive motor 13 has a structure that is transmitted to the steering column 10 through the worm gear 14, the drive shaft 16 of the drive motor 13 is a worm shaft via the electromagnetic clutch 18. It is connected with (17). Therefore, the driving force control of the drive motor 13 is made through the interruption of the electromagnetic clutch 18 by the electronic control unit.

However, in the conventional C-EPS, when the electromagnetic clutch 18 is connected in the driving motor 13 driving state and the steering wheel is momentarily rotated forward and backward, slippage occurs in the electromagnetic clutch 18 to generate abnormal noise. There is a disadvantage.

In addition, the use of expensive electronic clutches increases the price of the entire system.

Therefore, the present invention is to solve such a conventional problem, it is possible to lower the installation cost of the entire steering system by replacing the conventional clutch installed in the C-EPS with a tolerance ring (tolerance ring), the electronic clutch The purpose is to provide a C-EPS that can fundamentally eliminate the noise generated by the.

The present invention for realizing the above object is a steering angle sensor for detecting a steering angle of the steering wheel, a torsion bar installed in the steering column to generate a torsion during steering, a torque sensor for detecting the torsion of the torsion bar, and a vehicle Vehicle speed sensor that detects the speed of travel, motor installed to assist steering on the axis of steering column, worm gear installed to transfer driving power of motor to steering column, signal input from steering angle sensor and torque sensor A C-EPS including an electronic control unit for processing a driving force of a motor, wherein the driving shaft and the worm shaft of the motor are connected by riveted splines so as to transmit the driving force of the motor to the worm gear, and between the driving shaft and the spline. It characterized in that the tolerance ring is inserted into the wave shape and elastically deformed.

C-EPS equipped with such a tolerance ring can transmit power by being compressed in a radial direction up to a certain torque, but if a rotational force greater than the set value is applied, a force greater than the force pushing the wave shape in the radial direction will act. Slip occurs at and breaks the rotational force.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

1 is a cross-sectional view showing the main part of a conventional C-EPS,

2 is a cross-sectional view taken along line AA ′ of FIG. 1;

3 is a cross-sectional view showing the main parts of a C-EPS according to the present invention;

4 is a front view of a tolerance ring in accordance with the present invention;

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

10; Steering column 11; Torsion bar

12; Torque sensor 13; Drive motor

14; Worm gear 15; Ring gear

16; Drive shaft 17; Worm shaft

20; Tolerance ring 21; Spline

22; Rivet

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

Figure 3 is a schematic cross-sectional view showing the main portion of the C-EPS according to a preferred embodiment of the present invention, Figure 4 is a front view showing a tolerance ring according to the present invention.

A column type electric power steering device with a tolerance ring according to the present invention (hereinafter abbreviated as C-EPS) is a steering wheel, steering column, steering gear and steering linkage (steering linkage) It is based on a conventional rack and pinion type steering system.

In addition, the steering angle sensor for detecting the steering angle of the steering wheel to assist the steering force is not shown in the drawing, but is installed on one end of the steering column 10, the torsion generated during the steering column 10 torsion during steering Torque sensor 12 for detecting the torsion of the bar 11 and the torsion bar 11 is installed, and is provided with a vehicle speed sensor (not shown in the figure) for detecting the traveling speed of the vehicle.

In addition, a driving motor 13 having a driving force to assist the steering force is installed in a direction perpendicular to the axis of the steering column 10, it is possible to transfer the rotational force of the drive motor 13 to the rotational movement of the steering column (10). The worm gear 14 is installed on the drive motor 10 side, and the ring gear 15 is installed on the steering column 10 side and gear-coupled with each other.

In addition, an electronic control unit (not shown) for controlling a driving force of the driving motor 13 by processing signals input from a steering angle sensor (not shown), a vehicle speed sensor (not shown), and a torque sensor 12. It is configured to include.

In particular, according to the characteristic configuration of the present invention, as a means for intermittent driving force of the drive motor 13, the conventional electromagnetic clutch is replaced with a tolerance ring 20 to simplify the number of components.

That is, as shown in FIG. 3, the drive shaft 16 and the worm shaft 17 of the drive motor 13 are connected by a spline 21, and a tolerance ring () between the drive shaft 16 and the spline 21 is formed. When 20 is inserted and the driving force of the drive motor 13 is transmitted to the rotational force of the worm gear 14, the tolerance ring 20 is squeezed in the radial direction to transmit a power up to a predetermined torque, but the rotational force above the set value is transmitted to the tolerance ring 20. ) Acts as a force greater than the force pushing in the radial direction of the wave shape of the tolerance ring 20 to cause slippage in the spline 21 to break the rotational force.

Tolerance ring 20 for this purpose is made of a spring steel material has a predetermined elastic force, and has a wave shape to be inserted between the inner surface of the spline 21 and the outer surface of the drive shaft.

On the other hand, the spline 21 has a structure coupled by the rivet 22 so that the spline 21 on the drive shaft 16 side and the spline 21 on the worm shaft 17 side can be separated when a rotational force greater than a set value is applied.

Such a riveted spline 21 is a failure of the drive motor 13, breakage of the tolerance ring 20, or an unavoidable situation in which rotation is impossible, the rivet 22 is first when excessive force is applied to the power transmission unit. The driver's safety can be improved by causing damage.

In the above description, it should be understood that those skilled in the art can only make modifications and changes to the present invention without changing the gist of the present invention as it merely illustrates a preferred embodiment of the present invention.

As described above, according to the present invention, it is possible to reduce the installation cost of the entire steering system by replacing the conventional clutch installed in the C-EPS with a tolerance ring, and also to reduce the noise generated by the electromagnetic clutch. You can get rid of the effect.

Claims (1)

A steering angle sensor for detecting the steering angle of the steering wheel, a torsion bar installed in the steering column to generate a torsion during steering, a torque sensor for detecting a torsion of the torsion bar, a vehicle speed sensor for detecting a traveling speed of the vehicle, and a steering A motor installed to assist steering on the column axis, a worm gear installed to transfer the driving force of the motor to the steering column, and an electronic control to control the driving force of the motor by processing signals input from the steering angle sensor and the torque sensor. In a column type electric power steering apparatus including a unit, The drive shaft of the motor and the worm shaft are connected by riveted splines so as to transfer the driving force of the motor to the worm gear, The column type electric power steering device characterized in that the tolerance ring is inserted into the wave shape and elastically deformed between the drive shaft and the spline.