KR20060035873A - Free apatrness absorp structure of electrical power steering system - Google Patents

Abstract

The present invention relates to a column-type electric power steering apparatus in which a motor is installed on the steering column side to assist the steering force of the handle, and the technical configuration of the column-type electric power steering apparatus includes a worm shaft that is a reduction gear. At the outer diameter of the bearing 34 provided to support both ends of the 30, the cylindrical case 38 and the louver 36 are provided with a clearance absorbing structure 39 formed integrally.

According to the present invention of such a configuration, it is possible to absorb the play of the reducer due to the wear between the gear teeth to prevent the vibration, noise of the device in advance, thereby further improving the performance and reliability of the product.

C-EPS, Reducer, Worm Shaft, Louver, Spacing Absorption

Description

Free apatrness absorp structure of electrical power steering system

1 is a perspective view showing a conventional column type electric steering device.

2 is a cross-sectional view showing a rotational force transmission structure between the motor and the shaft according to FIG.

Figure 3 is an enlarged cross-sectional view showing the main portion of the column-type electric steering apparatus according to the present invention.

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.Bolbush

29.Fixed Edition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering apparatus for assisting a steering force of a vehicle by driving a motor. In particular, the present invention relates to a column type electric power steering apparatus for assisting a steering force of a steering wheel by installing a motor on a steering column side. The present invention relates to a reduction gear absorption structure of a column type electric power steering device that compensates for play caused by wear of the reducer and reduces noise by providing a clearance absorbing structure on the reducer side shaft.

In general, the power steering system is applied to the vehicle as a crisis means to reduce the steering force of the steering wheel (handle) to ensure the stability of the steering state. Such a power steering device is a conventional hydraulic power steering device (HPS) using hydraulic pressure. Hydraulic Power Steering System has been widely used in vehicles.However, unlike the conventional method of using hydraulic power, the electric power steering system (EPS; Electric Power Steering System) makes the driver's steering power easier by using the rotational power of the motor. Steering systems are commonly installed in vehicles.

The electric power steering device (EPS) drives the motor in the ECU according to the vehicle's driving conditions detected by the vehicle speed sensor and the steering torque sensor, thereby providing a light and comfortable steering feeling at low speeds, and a heavy steering feeling at high speeds. In addition, it gives a good direction stability, and in the emergency situation to achieve a steer steering to provide the operator with optimal steering conditions.

On the other hand, the electric power steering device is variously classified according to the installation position of the motor providing the auxiliary power, of which column type electric power steering system (Coulmn assist type Electric Power Steering System: hereinafter, abbreviated as "C-EPS" ) Is a motor installed outside the steering column disposed between the steering wheel and the gearbox so that the driver's steering wheel rotational force can be transmitted downward, and is configured to rotate the steering shaft therein. The driver's steering power will be assisted.

1 is a view showing a schematic configuration of the conventional C-EPS as described above. The conventional C-EPS is based on a general rack-pinion steering device, and has a hollow steering column 1. Inside the steering shaft 2 is installed to be rotatable, the steering shaft 2 is coupled to a steering wheel (not shown), one end is provided in the driver's seat, the other end is a universal joint (not shown) installed on the gearbox side ).

In addition, a motor 3 for steering assistance force is installed outside the steering column 2 in a direction orthogonal thereto, and a pair of drive gears are formed at the shaft end of the motor 3 and the center of the steering shaft 2. And a reduction gear composed of driven gear is provided to decelerate the motor output to assist the steering force.

At this time, the speed reducer used in the C-EPS is usually used as a pair of worms and worm wheel gear because the power transmission must be made in a staggered state.

That is, as shown in Figure 2, the shaft 30 of the motor is supported by a plurality of bearings 34 in the housing so that both ends thereof can be rotated in the state where the worm gear 32 is provided, the worm wheel gear ( 42 is configured to engage with the fin 32 in a state of being pressed into the outer peripheral portion of the steering shaft 2 inserted into the steering column 1 to receive a rotational force from the worm 32.

Therefore, the conventional C-EPS having the above-described configuration drives the motor in the ECU according to the driving conditions of the vehicle detected by the vehicle speed sensor, the steering torque sensor, and the like, and the driving force of the motor decreases the rotational speed through the above-described reduction gear. Is transmitted to the steering shaft to assist the driver in steering wheel steering.

However, since there is no separate backlash adjusting device on the reduction gear side of such a conventional column type electric steering device, wear due to frequent friction of the worm and the worm wheel is present as a play. Therefore, such a play has a problem that the vibration and noise of the device to reduce the performance and reliability of the product.

Therefore, the present invention has been made to improve the problems of the prior art as described above, by providing an absorption structure consisting of steel and louver integrally in the bearing outer diameter supporting the both ends of the worm shaft of the C-EPS, to wear between gear teeth It is an object of the present invention to provide a reducer clearance absorbing structure of a column type electric power steering device that can absorb the clearance caused and prevent the vibration and noise of the device.

As a technical means for achieving the above object, the present invention, in the column-type electric power steering device, the cylindrical case and the louver are integrated in the bearing outer diameter of both ends of the worm shaft is provided with a worm which is a reduction gear for reducing the rotational output of the motor. By providing a reducer play absorption structure of the electric power steering device, characterized in that the absorption structure consisting of a configuration.

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

In the present embodiment, the same reference numerals and names will be used for the same parts as those shown in the related art.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are explanatory cross-sectional views illustrating main parts of a column type electric steering apparatus according to the present invention, and FIG. 4 is an enlarged cross-sectional view taken along line AA of FIG. 3. to be.

As shown in FIG. 3, a column type electric power steering apparatus (hereinafter, abbreviated as C-EPS) includes a steering column in which a steering angle sensor (not shown) which detects a steering angle of a steering wheel. It is installed at one end of (1), the torsion bar 21 and the torque sensor 22 for detecting the torsion of the torsion bar 21 is installed inside the steering column (1), and detects the traveling speed of the vehicle A vehicle speed sensor (not shown) is provided and includes an ECU for calculating a signal input from the steering angle sensor, the vehicle speed sensor, and the torque sensor.

At this time, the drive motor (3) operated on the basis of the signal calculated from the ECU to assist the steering force is installed to be orthogonal in the direction perpendicular to the axis of the shaft 26, the worm 32 on the drive motor (3) side And a reducer composed of a worm wheel 42 is configured to reduce the motor output and transmit the decelerated motor to the shaft 26.

Particularly, in the present invention, when abrasion occurs due to frequent friction between the reduction gears, bearing parts supporting both ends of the worm shaft having the worm gear are formed so as to absorb the play between the gears caused by such abrasion. It is characterized by a clearance absorption structure.

That is, as shown in Figure 4, the clearance absorbing structure as described above, the louver 36 for the vibration is fitted in the outer diameter of the plurality of bearings 34 rotatably supporting the worm shaft 30, the louver 36 At the outside), a cylindrical case 38 made of steel is provided as one body with the louver 36.

Therefore, the C-EPS applied to the present invention having the above-described configuration calculates a motor driving command from the ECU according to the driving conditions of the vehicle detected by the vehicle speed sensor and the steering torque sensor and drives the motor at an appropriate rotational speed. The torque is transmitted to the steering shaft while being decelerated at the proper speed while passing through the reduction gear composed of the wheel and the worm wheel, to assist the steering wheel steering force of the driver.

At this time, in the present invention, since the louver 36 and the cylindrical case 38 made of steel are integrally formed in the outer diameter of the bearing 34 supporting the worm shaft, the bearing 34 is worn when the reduction gear is worn due to frequent friction. The louver 36 supporting the outer side can prevent the play from occurring, thereby reducing the noise caused by the irregular contact between the gear teeth.

As described above, according to the present invention, the reducer play-absorbing structure of the column type electric power steering device is provided with a play-absorbing structure in which steel and louver are integrally formed in the bearing outer diameters of both ends of the worm shaft. By absorbing the clearance, it is possible to prevent the vibration and noise of the device beforehand, thereby further improving the performance and reliability of the product.

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 is to be understood that one of ordinary skill can easily know.

Claims (1)

A steering angle sensor that detects the steering angle of the steering wheel, a torsion bar installed in the steering column to which torsion occurs when steering, a torque sensor that detects torsion of the torsion bar, a vehicle speed sensor that detects the speed of the vehicle, and a steering column A drive motor installed to assist the steering force on the shaft, a reducer consisting of a worm and a worm wheel to transmit the driving force of the motor to the steering shaft, and a signal input from the steering angle sensor, the vehicle speed sensor, and the torque sensor In the column type electric power steering apparatus comprising an ECU for controlling the driving force of the drive motor, In the outer diameter of the bearing 34 provided to support both ends of the worm shaft 30 having the worm 31, which is the reduction gear, a clearance absorbing structure 39 is formed in which the cylindrical case 38 and the louver 36 are integrally formed. Reducer play absorption structure of the electric power steering device characterized in that the configuration.

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