KR101076585B1 - Planetary Gear Apparatus Equipped with Apparatus for Backlash Elimination and Active Front Wheel Steering Having Same - Google Patents

Abstract

The present invention relates to a planetary gear device having a backlash reduction device and an active front wheel steering device having the same.

The present invention is a sun gear; At least one planetary gear external to the sun gear and bearing mounted on a shaft; A bearing holder in which a bearing insertion hole into which the bearing is inserted is eccentrically formed and a first groove is formed at one side of an outer circumferential surface thereof; A carrier for receiving the shaft and the bearing holder of the planetary gear and having a second groove formed therein; And it provides a planetary gear device having a backlash reduction device, characterized in that it comprises an elastic member provided in the first groove and the second groove.

In addition, the present invention is an active front wheel steering device of the vehicle, the active front wheel steering device is a sun gear; At least one planetary gear external to the sun gear and bearing mounted on a shaft; A bearing holder in which a bearing insertion hole into which the bearing is inserted is eccentrically formed and a first groove is formed at one side of an outer circumferential surface thereof; A carrier for receiving the shaft and the bearing holder of the planetary gear and having a second groove formed therein; And it provides an active front wheel steering apparatus having a planetary gear device having a backlash reduction device, characterized in that it comprises an elastic member provided in the first groove and the second groove.

According to the present invention, a bearing holder having a bearing insertion hole into which a bearing mounted on a shaft of a planetary gear is fitted is eccentrically formed and a first groove is formed at one side of the outer circumferential surface of the bearing holder (or worm wheel) in which the second groove is formed. And mounting the elastic member (especially the torsion coil spring) in the first groove and the second groove so that the bearing holder rotates about the planetary gear shaft by eccentricity by the elastic force continuously applied by the elastic member. It is effective to reduce the backlash between the sun gear and the planetary gear by pushing in.

Planetary Gear, Backlash, Reduced, AFS, Active Front Wheel Steering, Bearing

Description

Planetary Gear Apparatus Equipped with Apparatus for Backlash Elimination and Active Front Wheel Steering Having Same}

The present invention relates to a planetary gear device having a backlash reduction device and an active front wheel steering device having the same. More specifically, a bearing holder having an eccentric bearing insertion hole into which a bearing mounted on the shaft of the planetary gear is fitted and a first groove formed on one side of the outer circumferential surface thereof is mounted on a carrier (or worm wheel) in which the second groove is formed. An elastic member (especially a torsion coil spring) is mounted in the first groove and the second groove so that the bearing holder rotates about the planetary gear shaft by eccentricity by the elastic force continuously applied by the elastic member and pushes the planetary gear shaft in the direction of sun gear. The present invention relates to a planetary gear device having a backlash reduction device having an effect of reducing backlash between a sun gear and a planetary gear, and an active front wheel steering device having the same.

The steering device of the vehicle is a device for changing the driving direction of the vehicle at the driver's will, and is a device for assisting the driver in driving the vehicle in a desired direction by arbitrarily changing the center of rotation of the front wheel.

In addition, the Power Steering Apparatus assists the driver's steering wheel manipulation power by using a device that provides steering assistance power when the driver operates the steering wheel, thereby enabling a smaller power. It is a device to change the direction of the car.

Such a power assisted steering device is largely classified into a hydraulic power assisted steering device (HPS) and an electric power assisted steering device (EPS).

The hydraulic power assisted steering system is provided when the hydraulic pump connected to the rotating shaft of the engine supplies the hydraulic fluid to the working cylinder, and the hydraulic assist hydraulic power of the hydraulic oil is provided so that the rack bar moves in the horizontal direction, so that both wheels are moved. It is a device that allows the driver to steer with little force because it is turning.

On the other hand, the electric power assist steering device includes a motor and an electronic control unit (ECU) in a rack bar or column instead of a hydraulic pump and a working cylinder. The device is supplied.

Recently, the steering shaft is separated between the steering wheel and the steering column to actively cope with the external environment such as a strong wind blowing while driving or a road surface that is not symmetrical to the left and right. Active front wheel steering that adjusts the steering angle by continuously detecting the steering angle that changes from time to time without direct transmission to the steering column, comparing it with various information of the vehicle, and transmitting it as an electrical signal to the motor that controls the steering shaft rotation of the steering column. Device (AFS: Active Front Wheel Steering) has emerged.

In addition, such an active front wheel steering apparatus is provided with a gear ratio converter for converting a gear ratio between an input and an output in the gear unit.

1 is a block diagram of an active front wheel provision apparatus of a conventional vehicle, Figure 2 is a schematic diagram showing a gear ratio converter.

As shown in FIG. 1, an active front wheel steering apparatus of a conventional vehicle includes a steering wheel 101, a steering shaft 103 connected to a steering wheel 101, a steering column 105 surrounding a steering shaft 103, and steering. The first motor 111 for driving the input angle sensor 107 formed at the lower end of the column 105, the gear ratio converter 109 formed below the input angle sensor 107, and the gear ratio converter 109. , A first motor position sensor 113 provided at the first motor 111, an output angle sensor 115 formed at a lower side of the gear ratio converter 109, a vehicle speed sensor 117 detecting a speed of a vehicle, and a gear ratio It is formed on the lower side of the converter 109, the rack-pinion mechanism unit 121 for converting the rotational movement of the steering shaft 103 into a linear movement of the rack bar 119, the agent for supplying steering auxiliary power to the rack bar 119 2 includes an ECU 125 that receives various signals from the motor 123, the input angle sensor 107, the first motor position sensor 113, and the output angle sensor 115. It is configured.

In addition, as shown in FIG. 2, the conventional gear ratio converting apparatus includes an input shaft 210, a first stage external to the first sun gear 220 and the first sun gear 220 formed at the lower end of the input shaft 210. The second sun gear 270 which is connected to the planetary gear 270, the first stage planetary gear 270 and the planetary gear shaft 275, and the second stage planetary gear 280, 230, an output shaft 240 connected to the second sun gear 230, a worm wheel 250, and a worm shaft 260.

The operating principle of the active front wheel steering device and the gear ratio converter of a conventional vehicle having such a configuration is as follows.

As the driver manipulates the steering wheel 101, when the input shaft 210 rotates, the first sun gear 220 formed at the lower end of the input shaft 210 rotates in association with the input shaft 210.

In addition, in this case, the first gear planetary gear 270 which is circumscribed with the first sun gear 220 is rotated, and the second gear planet which is connected by the first gear planetary gear 270 and the planetary gear shaft 275 is rotated. Gear 280 is rotated.

Finally, the second sun gear 230, which is external to the second gear planetary gear 280, rotates, so that the output shaft 240 formed to extend from the second sun gear 230 rotates so that the driver's steering wheel ( 101) the steering force generated by the operation is to be transmitted to the rack-pinion mechanism portion 121.

However, the above process is a case where the first motor 111 does not operate, and when the first motor 111 operates, the following changes occur.

Electrical signals are generated from the vehicle speed sensor 117 for detecting the speed of the vehicle, the input angle sensor 107 and the output angle sensor 115 for detecting a change in the steering angle, and the first motor position sensor 113, respectively. When reaching 125, the ECU 125 transmits an electrical signal to the first motor 111 to drive the first motor 111.

In addition, as the first motor 111 is driven by the above process, the worm wheel 260 which is connected to the motor shaft (not shown) also rotates and is thereby engaged with the worm shaft 260. The rotation and finally the carrier 290 is integrally formed with the worm wheel 250 is rotated to adjust the ratio of the output angle to the input angle.

The active front wheel steering device of the vehicle operates when the driver drives the steering wheel 101 in one direction when the vehicle is traveling at a high speed, so that the input shaft 210, the first sun gear 220, and the first gear planetary gear 270 are operated. Even if it rotates, the ECU 125 rotates the worm wheel 250 and further the carrier 290 in a direction that prevents rotation of the second stage planetary gear 280 connected to the first stage planetary gear 270. By controlling the motor 111, the rotation angle of the output shaft 240 is smaller than the rotation angle of the input shaft 210, thereby assisting in safe driving.

On the other hand, the active front wheel steering device of the vehicle, when the vehicle is in a low speed state for parking or the like, the first motor 111 in a direction to make the rotation angle of the output shaft 240 larger than the rotation angle of the input shaft 210. By controlling, the driver can easily drive with less force.

And the first sun gear 220, the second sun gear 230, the first stage planetary gear 270, the second stage planetary gear 280 of the conventional gear ratio converter as shown in Figure 2 is generally formed as a helical gear Helical gears are gears in which the rows of gear teeth are inclined at an angle, not parallel to the axis of rotation of the gears. These helical gears are meshed with each other when compared with the case where the rows of gear teeth are parallel to the axis of rotation of the gears. The teeth are in contact with each other because of the long length, so they can transmit more force and the gear teeth are inclined to rotate more smoothly.

By the way, in the planetary gear device used for the gear ratio converter of such a structure, a backlash exists between gear teeth which engage | engage, respectively.

A backlash is a gap between gear teeth adjacent to each other, and more specifically, refers to a space generated behind the meshed gear teeth when the gear teeth of one gear and the gear teeth of another gear mesh with each other.

On the other hand, in a gear device in which the drive gear and the driven gear mesh, there is no problem when the speed of the drive gear and the driven gear is constant, but if the speed is not constant for some reason, noise may occur due to the backlash.

That is, before the gear value of the drive gear and the driven gear which meshed with each other finishes biting, the gear value of a driven gear hits the back of the gear value of a drive gear, and noise generate | occur | produces.

In the case of the steering device of the car, the noise generated by the backlash causes discomfort during steering and increases as the gear teeth wear out.

On the other hand, there are two methods for adjusting the backlash between the gear teeth: static method and dynamic method, and again static method, the effective thickness of the gear and the bite center distance of the gear. The linear combination method and the rotary movement method are used according to the mutual combination of the two methods.For the dynamic method, the forced tooth contact method for adjusting the effective tooth thickness using the elastic force of the elastic body and also the elastic force of the elastic body There is a forced center distance reduction method that adjusts the bite center distance of gear teeth by using.

Among the methods for adjusting the backlash between the gear teeth mentioned above, Figure 3a is a view showing an example of the linear movement method of the static method, Figure 3b is a view showing an example of the rotation movement method of the static method, In particular, when the linear force or the rotational torque in FIG. 3b to move the gear in a straight line or parallel along the center line in Figure 3a generated by the elastic force of the elastic body is an example of the forced center distance reduction method of the dynamic method.

However, when the small adjustment method shown in FIG. 3b of the above-mentioned forced center distance reduction method is applied to the planetary gear device, a device capable of continuously providing rotational torque to the planetary gear is required.

In order to solve this problem, the present invention provides a bearing holder in which a bearing insertion hole into which a bearing mounted on a shaft of a planetary gear is fitted is eccentrically formed, and a first holder is formed at one side of an outer circumferential surface thereof, and a carrier having a second groove (or Worm wheel) and elastic members (especially torsion coil springs) are mounted in the first and second grooves so that the bearing holder rotates about the planetary gear shaft by eccentricity by the elastic force continuously applied by the elastic member. It is an object of the present invention to provide a planetary gear device having a backlash reduction device having an effect of reducing backlash between the sun gear and the planetary gear by pushing in the sun gear direction and an active front wheel steering device having the same.

The present invention to achieve this object is a sun gear; At least one planetary gear external to the sun gear and bearing mounted on a shaft; A bearing holder in which a bearing insertion hole into which the bearing is inserted is eccentrically formed and a first groove is formed at one side of an outer circumferential surface thereof; A carrier for receiving the shaft and the bearing holder of the planetary gear and having a second groove formed therein; And it provides a planetary gear device having a backlash reduction device, characterized in that it comprises an elastic member provided in the first groove and the second groove.

In addition, the present invention is an active front wheel steering device of the vehicle, the active front wheel steering device is a sun gear; At least one planetary gear external to the sun gear and bearing mounted on a shaft; A bearing holder in which a bearing insertion hole into which the bearing is inserted is eccentrically formed and a first groove is formed at one side of an outer circumferential surface thereof; A carrier for receiving the shaft and the bearing holder of the planetary gear and having a second groove formed therein; And it provides an active front wheel steering apparatus having a planetary gear device having a backlash reduction device, characterized in that it comprises an elastic member provided in the first groove and the second groove.

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 the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, the planetary gear device having the backlash reduction device according to the embodiment of the present invention may be applied to a gear ratio converter including a first gear planetary gear and a second gear planetary gear, as shown in FIG. It can also be applied to a gear device (i.e., a planetary gear device consisting of sun gear, planetary gear, ring gear, carrier).

In addition, the planetary gear device provided with the backlash reduction device according to the embodiment of the present invention will be particularly useful when applied to an active front wheel steering device of a vehicle.

At this time, when the present invention is applied to the gear ratio converter composed of the first stage planetary gear and the second stage planetary gear as shown in Figure 2 is the bearing holder and the elastic member of the configuration of the carrier or worm wheel It can be mounted anywhere or on both the carrier and the worm wheel.

Hereinafter, the present invention will be described based on a case where the present invention is applied to a gear ratio converting apparatus including a first stage planetary gear and a second stage planetary gear as shown in FIG. 2.

4 is an assembled perspective view of a planetary gear device having a backlash reduction device according to an embodiment of the present invention, Figure 5 is a plan view of a planetary gear device provided with a backlash reduction device according to an embodiment of the present invention and Figure 6 An assembly perspective view of a guide among planetary gear devices provided with a backlash reduction device according to an embodiment of the present invention.

4, 5, and 6, the planetary gear device having the backlash reduction device 400 according to the embodiment of the present invention is external to the sun gear (not shown), sun gear (not shown) and the shaft One or more planetary gears 440 equipped with bearings 430 at 480, bearing insertion holes 490 through which the bearings 430 are eccentrically formed, and a first groove 460 is formed at one side of the outer circumferential surface thereof. The carrier 475 according to the embodiment of the present invention, which receives the bearing holder 410, the shaft 480 of the planetary gear 440, and the bearing holder 410 and has a second groove 470, is referred to as a carrier. .), Characterized in that it comprises an elastic member 420 provided in the first groove 460 and the second groove 470.

The sun gear (not shown) corresponds to the first sun gear 220 and the second sun gear 230 shown in FIG. 2, but the sun gear is not shown in FIG. 4 for convenience of understanding.

The planetary gear 440 corresponds to the first stage planetary gear 270 and the second stage planetary gear 280 shown in FIG. 2, and the planetary gear 440 is external to the sun gear (not shown) and the shaft 480. The bearing 430 is mounted to rotate in conjunction with the sun gear (not shown).

In the bearing holder 410, a bearing insertion hole 490 into which the bearing 430 is inserted is eccentrically formed with respect to the center of the bearing holder 410, and a first groove 460 is formed at one side of the outer circumferential surface thereof.

Here, the meaning that the bearing insertion hole 490 is formed eccentrically with respect to the center of the bearing holder 410 means that the central axis O 'of the bearing holder is a predetermined distance from the bearing center axis O as shown in FIG. It is formed spaced apart.

In addition, one side of the outer circumferential surface on which the first groove 460 is formed is particularly referred to as bearing holder 430 when the center of the bearing holder 410 is connected to the center of the bearing 430 after the bearing 430 is inserted into the bearing holder 410. It means the opposite side of the portion where the central axis O of the bearing 430 is located with respect to the central axis O 'of the 410 (see FIG. 7).

Bearing holder 410 is preferably formed of a steel or plastic material, but is not necessarily limited thereto.

The diameter of the bearing insertion hole 490 may be formed to be somewhat smaller than the diameter of the bearing 430 so that the bearing 430 may be press-fit / fixed.

As described above, the first groove 460 is formed at one side of the outer circumferential surface of the bearing holder 410. In FIG. 4, when the first groove 460 is recessed to a predetermined depth from the upper surface of the bearing holder 410. Although not limited thereto, the elastic member 420 is inserted into the bearing holder 410 by drilling a hole having a predetermined size on one side of the outer circumferential surface of the bearing holder 410, and then inserting and fixing the elastic member 420. As long as it is formed to apply rotational torque, anything may be possible.

In addition, a first fixing hole 415 may be formed on the outer circumferential surface of the bearing holder 410. The first fixing hole 415 is connected to the second fixing hole 477 formed in the carrier 475 to fix the fixing means 495. The second fixing hole 477 and the first fixing hole 415 can be mounted therethrough.

The fixing means 495 is used to fix the position of the bearing holder 410 in the state in which elastic force is applied to the elastic member 420 at the time of initial assembly of the planetary gear device of the present invention. Preferred but not necessarily limited to this.

The carrier 475 accommodates the shaft 480 of the planetary gear 440 and the bearing holder 410. A second groove 470 is formed in the carrier 475 spaced apart from the first groove 460. The second fixing hole 477 may be formed to penetrate through the first fixing hole 415.

That is, in the conventional carrier 290 (see FIG. 2), the shaft 480 of the planetary gear 440 and the bearing 430 are press-fitted / fixed so that the planetary gear 440 is relative to the conventional carrier 290 (see FIG. 2). The carrier 475 according to the embodiment of the present invention has a bearing holder 410 and an elastic member 420 in addition to the shaft 480 and the bearing 430 of the planetary gear 440 accommodated in the conventional carrier. ), And further accommodates the guide 450 to be described later.

To this end, it will be preferable that the groove A as shown in FIG. 4 is formed in the carrier 475 so that the bearing holder 410, the elastic member 420, and furthermore, the guide 450 can be inserted. .

The second groove 470 is formed spaced apart from the position of the first groove 460 when the bearing holder 410 is inserted into the carrier 475, the first groove 460 and the second groove 470 It is preferable that the distance between the?) Is determined so that the rotational torque of the elastic member 420 can be properly transmitted to the bearing holder 410.

4 illustrates a case where the second groove 470 is formed to be recessed downward from the upper surface of the carrier 475, but is not necessarily limited thereto.

The guide 450 serves to support the bearing holder 410 and the elastic member 420. In the guide 450, the bearing through hole 455 is perforated in the guide plate 451, and the elastic member fixing part ( 453) is formed to protrude. (See Fig. 6).

Since the bearing 430 is fitted into the bearing through hole 455, the planetary gear 440 rotates relative to the guide 450, and the bearing holder 410 into which the bearing 430 is fitted is attached to the guide plate 451. Relative rotation.

That is, only the bearing 430 is fitted to the bearing holder 410 so as to surround the outer circumferential surface of the bearing 430, so that the bearing holder 410 and the guide plate 451 are not coupled to each other, so that the bearing holder 410 is a guide plate ( 451 is rotatable relative to the top surface.

The elastic member fixing part 453 is formed to protrude from the guide plate 451. The elastic member fixing part 453 is fitted into the first groove 460 and the second groove 470, and the second groove 470 is formed. The fixed shaft serves to fix the position of the elastic member 420 to apply a rotating torque to the bearing holder 410.

As shown in FIG. 4, the backlash reduction device 400 having such a configuration may be mounted on each bearing 430 of the planetary gear 440 or may be mounted on only one side thereof. will be.

7 is a plan view showing an operating state of the backlash reduction apparatus according to an embodiment of the present invention.

Referring to Figures 4, 6 and 7 will be described briefly the operation of the backlash reduction apparatus according to an embodiment of the present invention.

First, the operator inserts the bearing holder 410 into the bearing 430 before inserting the shaft 480 and the bearing 430 of the planetary gear device into the carrier 475.

In this case, when the guide 450 is mounted, the bearing 430 is inserted through the bearing through hole 455 (see FIG. 6), and then the bearing holder 410 is inserted into the bearing 430 again.

After inserting one side of the elastic member 420, in particular, the torsion coil spring, into the first groove 460 of the bearing holder 410 and the other side into the second groove 470 of the carrier 475. The bearing holder 410 and the elastic member 420 are inserted into the carrier 475 in a state in which the bearing holder 410 is slightly rotated so that the elastic force acts on the elastic member 420.

At this time, the first fixing hole 415 and the second fixing hole 477 may be connected and fixed by the fixing means 495 to maintain the state in which the elastic force is applied to the bearing holder 410.

That is, the worker has the first fixing hole 415 and the second fixing hole 470 so that the first fixing hole 415 and the second fixing hole 470 can be connected in a state in which the bearing holder 410 is provided with an elastic force. Since the fixing means 495 is mounted through the first fixing hole 415 and the second fixing hole 470, the bearing holder 410 is placed in a state where elastic force is applied to the bearing holder 410. The position can be fixed.

After assembling the sun gear (not shown) so that the planetary gear 440 is external and removing the fixing means 495, the elastic member 420 applies a rotating torque to the bearing holder 410 (D in FIG. 7). Direction) Therefore, the center of rotation is eccentric (in Fig. 7, the bearing holder 410 does not rotate about the bearing holder center axis O ', but rotates around the bearing center axis O). As the 410 rotates about the bearing central axis O, the bearing 430 and the shaft 480 are pushed in the D 'direction (that is, the sun gear direction), and thus the planetary gear 440 and the sun gear (not shown) The backlash between the gear teeth of the case is reduced.

At this time, the acting point at which the force that the bearing holder 410 pushes the bearing 430 acts, the eccentricity with respect to the bearing central axis 0 of the bearing holder central axis O 'and the bearing insertion hole 490 (see FIG. 4). ) Diameter and the like.

The above description exemplarily illustrates the technical idea of the present invention, and those skilled in the art may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of 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 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.

1 is a block diagram of an active front wheel provision apparatus of a conventional vehicle;

2 is a schematic view showing a gear ratio converter;

3A is a diagram showing an example of the linear movement method in the static method;

3B shows an example of a rotational movement method of the static method;

4 is an assembled perspective view of a planetary gear device having a backlash reduction device according to an embodiment of the present invention;

5 is a plan view of a planetary gear device having a backlash reduction device according to an embodiment of the present invention;

Figure 6 is an assembled perspective view of the guide of the planetary gear device having a backlash reduction apparatus according to an embodiment of the present invention; And

7 is a plan view showing an operating state of the backlash reduction apparatus according to an embodiment of the present invention.

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

101: steering wheel 103: steering shaft

105: steering column 107: input angle sensor

109: gear ratio inverter 111: first motor

113: first motor position sensor 115: output angle sensor

117: vehicle speed sensor 119: rack bar

121: rack-pinion mechanism part 123: second motor

210: input shaft 220: first sun gear

230: second sun gear 240: output shaft

250: worm wheel 260: worm shaft

270: first gear planetary gear 275: planetary gear shaft

280: second stage planetary gear 290: carrier

410: bearing holder 420: elastic member

430: bearing 440: planetary gear

450: guide 460: first groove

470: second groove 480: shaft

490: bearing insert hole

Claims (11)

Sun gear; At least one planetary gear external to the sun gear and bearing mounted on a shaft; A bearing holder in which a bearing insertion hole into which the bearing is inserted is eccentrically formed and a first groove is formed at one side of an outer circumferential surface thereof; A carrier for receiving the shaft and the bearing holder of the planetary gear and having a second groove formed therein; And An elastic member provided in the first groove and the second groove Planetary gear device provided with a backlash reduction device characterized in that it comprises a. The method of claim 1, The planetary gear device having a backlash reduction device, characterized in that the first fixing hole is formed on the outer peripheral surface of the bearing holder. The method of claim 1, And a guide for supporting the bearing holder and the elastic member are mounted to the carrier. The method of claim 1, The elastic member is a planetary gear device having a backlash reduction device, characterized in that the torsion coil spring. The method of claim 2, The carrier has a planetary gear device having a backlash reduction device, characterized in that the second fixing hole penetrates to be connected to the first fixing hole. The method of claim 5, The planetary gear device having a backlash reduction device, characterized in that the fixing means is mounted to the first fixing hole and the second fixing hole. The method of claim 6, The fixing means is a planetary gear device having a backlash reduction device, characterized in that the pin. The method of claim 1, The first groove is a planetary gear device having a backlash reduction device, characterized in that the recess is formed in a predetermined depth from the upper surface of the bearing holder. The method of claim 1, The first groove is a planetary gear device having a backlash reduction device, characterized in that formed by drilling a hole of a predetermined size on one side of the outer peripheral surface of the bearing holder. The method of claim 3, wherein The guide is a planetary gear device having a backlash reduction device, characterized in that the bearing through-hole is perforated in the guide plate and the elastic member fixing portion is protruded. In the active front wheel steering of a vehicle, The active front wheel steering device Sun gear; At least one planetary gear external to the sun gear and bearing mounted on a shaft; A bearing holder in which a bearing insertion hole into which the bearing is inserted is eccentrically formed and a first groove is formed at one side of an outer circumferential surface thereof; A carrier for receiving the shaft and the bearing holder of the planetary gear and having a second groove formed therein; And An elastic member provided in the first groove and the second groove Active front wheel steering apparatus having a planetary gear device having a backlash reduction device characterized in that it comprises a.

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