KR101137109B1 - Electric Power Steering Apparatus of Non-circulating Ball Screw Type Equipped with Elastic Spacer - Google Patents

Abstract

The present invention relates to an acyclic ball screw electric steering device.

The present invention provides an electric steering apparatus including a motor for supplying steering auxiliary power, wherein a rack bar having a first screw groove on an outer circumferential surface thereof is provided on an inner circumferential surface thereof with a second screw groove facing the first screw groove. Non-circulating comprising a ball nut surrounding, the ball in contact with the first screw groove and the second screw groove, a stop for restraining the movement of the ball, a spacer inserted between the ball It provides a type ball screw electric steering device.

According to the present invention, by providing a non-circulating ball screw electric steering device having a spacer with elasticity between the balls, steering is absorbed by absorbing energy even when the ball reaches the end while reducing friction and noise as compared to the conventional electric steering device. There is no effect of end jamming in the mechanism part.

Acyclic Ball Screw Electric Steering, Ball, Ball Nut, Spacer

Description

Electric Power Steering Apparatus of Non-circulating Ball Screw Type Equipped with Elastic Spacer

1 is a schematic configuration diagram of an electric steering apparatus according to the prior art,

2 is a partial cross-sectional view of the electric steering apparatus according to the prior art,

3 is a cross-sectional view of a non-cyclic ball screw electric steering apparatus having no spacer according to the prior art;

4 is a cross-sectional view of an acyclic ball screw electric steering apparatus having a spacer according to a first embodiment of the present invention;

5 is a cross-sectional view of a spacer according to a second embodiment of the present invention;

Figure 6 is a cross-sectional view of the acyclic ball screw electric steering apparatus when the ball and the spacer of the present invention is located at the end,

7A is a schematic diagram showing a traveling direction of a ball according to the prior art;

7B is a schematic view showing the advancing direction of the ball and the spacer according to the present invention.

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

135: rack pinion mechanism 315: ball

405: ball nut 410: rack bar

415: spacer 420: first screw groove

425: second screw groove 430: stop

The present invention relates to an acyclic ball screw electric steering device.

More specifically, the ball does not circulate by the stops formed in the rack bar or the ball screw groove, and by inserting an elastic spacer between the ball and the ball, even when the ball reaches the end, it absorbs energy and ends at the steering mechanism part. It relates to a non-circulating ball screw electric steering device characterized in that there is no locking phenomenon.

As a steering device of a vehicle, a hydraulic power steering device (Hydraulic Power Steering Apparatus) using a hydraulic pressure of a hydraulic pump is generally used, but in recent years, an electric power steering device (Electric Power Steering Apparatus) using a motor is becoming more and more common.

1 is a schematic configuration diagram of an electric steering apparatus according to the prior art.

As shown in FIG. 1, a general electric steering device includes a steering system 100 extending from a steering wheel 105 to both wheels 150 and an auxiliary power mechanism 160 for supplying steering auxiliary power to a steering system. do.

The steering system 100 has a steering shaft having an upper end connected to the steering wheel 105 to rotate together with the steering wheel 105 and a lower end connected to the pinion shaft 120 via a pair of universal joints 115. 110). In addition, the pinion shaft 120 is connected to the rack bar 155 through the rack-pinion mechanism 135, and both ends of the rack bar 155 are connected to the wheel 150 of the vehicle through the tie rod 140 and the knuckle arm 145. )

Rack-pinion mechanism 135 is formed by engaging the pinion gear 125 and the rack gear 130 formed on one side of the outer circumferential surface of the rack bar 155 is formed on the bottom of the pinion shaft 120, rack-pinion mechanism portion The rotational motion of the pinion shaft 120 is changed to the linear motion of the rack bar 155 through the 135. Therefore, when the driver operates the steering wheel 105, the pinion shaft 120 rotates, the rack bar 155 linearly moves in the axial direction according to the rotation of the pinion shaft 120, and the linear movement of the rack bar 155 is performed. The tie rod 140 and the knuckle arm 145 are steered to the wheel 150.

The auxiliary power mechanism 160 detects the steering torque applied by the driver to the steering wheel 105 and outputs an electrical signal proportional to the detected steering torque. An electronic control unit (ECU) that generates a control signal based on the motor, a motor 165 and a belt that generate steering assistance power based on the control signal transmitted from the electronic control unit 163. It is configured to include a belt-type transmission device 170 for transmitting the auxiliary power generated in 165 to the rack bar 155.

2 is a partial cross-sectional view of the electric steering apparatus according to the prior art.

As shown in FIG. 2, a general electric steering device includes a rack bar 155 having a rack gear on one side of an outer circumferential surface of the vehicle and a pinion shaft 120 having a pinion gear engaged with the rack gear, and a ball ( A ball screw part 200 including a ball nut 205 engaged with the ball screw 215 via a 210, a belt-type transmission device 170 connecting the ball nut 205 and the motor shaft 235, and It is configured to include a motor (165).

The pinion shaft 120 is connected to a steering wheel through a steering shaft, and a rack bar 155 having a predetermined length of a screw formed on one side of an outer circumferential surface thereof is embedded in the rack housing 230. In addition, the rack housing 230 is divided into a first housing 225 on the rack gear side and a second housing 220 on the motor side.

Belt-type transmission 170 is formed including a belt connecting the motor shaft 235 and the ball nut 205, the steering auxiliary power generated by the motor 165 in proportion to the steering torque applied to the steering wheel. The nut 205 passes through the rack bar 155.

3 is a cross-sectional view of an acyclic ball screw electric steering apparatus having no spacer according to the prior art.

As shown in FIG. 3, the non-cyclic ball screw electric steering apparatus having no spacer according to the prior art is described in the present invention as filed with No. 10-2006-0075639 filed on August 10, 2006 by the present applicant. Its components are described for this purpose. The non-cyclic ball screw electric steering apparatus without a spacer includes a rack bar 310 having a first screw groove 320 on its outer circumferential surface, a ball nut 305 having a second screw groove 325 on its inner circumferential surface, and a first. It comprises a ball 315 in contact with the screw groove 320 and the second screw groove 325 and a stop 330 to restrain the movement of the ball 315.

According to the conventional technology, when the ball reaches the end, the impact energy cannot be absorbed when the ball reaches the end, so that the ball does not have complete rolling friction.

Therefore, the present invention has been invented to solve the above problems, the ball absorbs energy even when the ball reaches the end while reducing the noise by the complete rolling friction, so that the elasticity without the end catching phenomenon in the steering mechanism portion The main object of the present invention is to provide a non-cyclic ball screw electric steering apparatus having a spacer.

In order to achieve the above object, the present invention provides a rack bar having a first screw groove on an outer circumferential surface of an electric steering apparatus including a motor for supplying steering auxiliary power, and an inner circumferential surface of a second screw groove facing the first screw groove. And a ball nut surrounding the rack bar, a ball contacting the first screw groove and the second screw groove, a stop portion for restraining the movement of the ball, and a spacer inserted between the balls. It provides a non-circulating ball screw electric steering device characterized in that the.

Hereinafter, preferred 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 addition, in describing the present invention, when it is determined that the detailed description of the related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

4 is a cross-sectional view of an acyclic ball screw electric steering apparatus having a spacer according to a first embodiment of the present invention.

As shown in FIG. 4, the non-cyclic electric steering apparatus including the spacer 415 according to the first embodiment of the present invention includes a rack bar 410 having a first screw groove 420 on an outer circumferential surface thereof, and the first screw. A second screw groove 425 facing the groove 420 is provided on an inner circumferential surface thereof, and includes a ball nut 405, the first screw groove 420, and the second screw groove 425 surrounding the rack bar 410. It comprises a ball 315 in contact with, a stop 430 to restrain the movement of the ball 315 and a spacer 415 inserted between the ball 315.

The first screw groove 420 is formed in a spiral shape on the outer circumferential surface of the rack bar 410, the second screw groove 425 is formed on the inner circumferential surface of the ball nut 405 opposite to the first screw groove 420. The ball nut 405 surrounds the outer circumferential surface of the rack bar 410 and the ball 315 is in contact with the first screw groove 420 and the second screw groove 425, so that the rotational movement of the ball nut 405 is the rack bar 410. The power of the motor (not shown) is transmitted to the rack bar 410 by changing the linear motion to.

The stopper 430 is formed at one side of the first screw groove 420 to constrain the movement of the ball 315, and may be formed at both sides of the first screw groove 420 as necessary, and the second screw groove ( 425 may be formed.

In addition, the stopper 430 may be formed by inserting a pin or a ball into the first screw groove 420, or may be formed by providing an elastic body or a protrusion such as a spring in the first screw groove.

According to the non-circulating ball screw electric steering device, the ball 315 moves along the first screw groove 420 and the second screw groove 425, but movement of the ball 315 is restricted by the stopper 430, thereby preventing circulation. The noise and friction are reduced in the door compared to the circular ball screw.

At this time, in the case of the non-cyclic ball screw electric steering device without the spacer, the ball 315 is made of only the metal balls 315 having no elasticity at the moment when the ball 315 reaches the stop portion 330 to absorb the impact energy due to the impact. Since the steering wheel operation can not be the end of the phenomenon occurs in the steering mechanism including the steering wheel.

Therefore, according to the present invention, since the spacer having elasticity is inserted between the balls, the spherical spacer is deformed into an elliptical shape by elasticity and absorbs the impact amount caused by the impact of the balls, so that the steering wheel operation efficiency is smoothly dropped so that the end locking phenomenon is eliminated. .

The spacer 415 is about 0.01 to 0.09 mm in diameter smaller than the ball 315, and is contacted and rolled between the balls. Thus, the arrangement of the spacers 415 inserted between the balls is a ball 315. It is preferable to be arranged alternately with, but not necessarily limited thereto, it is possible to have two or more balls are arranged between the spacers according to the degree of end catching or the degree of noise.

5 is a cross-sectional view of a spacer of the acyclic ball screw electric steering apparatus according to the second embodiment of the present invention.

As shown in FIG. 5, the spacer 415 of the acyclic ball screw electric steering apparatus provided with the spacer 415 according to the present invention may be a solid spherical elastic body 505, and the inner body is a rigid body 510. It may be a sphere composed of an elastic body 515, may be a hollow spherical elastic body 525 of the hollow 520. As the material of the spacer having elasticity, an elastic member made of rubber or silicone is preferably used, but is not necessarily limited thereto. An elastic member capable of deformation and restoration by elasticity may be used.

However, since the other configurations and operations are the same as in the first embodiment of the present invention, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

Figure 6 is a cross-sectional view of the non-cyclic ball screw electric steering apparatus when the ball and the spacer according to the present invention is located at the end, Figure 7a is a schematic diagram showing the traveling direction of the ball according to the prior art, Figure 7b is a ball according to the present invention It is a schematic diagram which shows the advancing direction of a spacer.

As shown in FIG. 6, when the ball 315 reaches the end, the first screw groove 420 can no longer be moved by the stopper 430, and the ball 315 and the ball 315 can be moved. The inserted spacer 415 is deformed elliptically by elasticity between the balls 315 and absorbs collision energy with the balls.

Therefore, compared to the non-circulating ball screw electric steering apparatus which consists only of the existing metallic balls which do not have a spacer by such elastic deformation, there exists an effect that the edge locking phenomenon of a steering mechanism part including a steering wheel is eliminated.

In addition, as shown in FIG. 7A, the rolling direction of the ball of the non-cyclic ball screw electric steering apparatus without a spacer is opposite to each other at the contact portion 705 of the ball 315 and the ball 315. Collision occurs, but as shown in FIG. 7B, in the case of the non-cyclic electric steering apparatus including the spacer according to the present invention, the rolling direction of the ball 315 and the spacer 415 is rotated by meshing with the ball 315. Since the contact portion 710 of the spacer 415 is in the same direction, collision with the reverse cloud does not occur and complete rolling friction is achieved, thereby improving efficiency and reducing noise.

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 spirit 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.

As described above, according to the present invention, there is an effect of absorbing energy even when the ball reaches the end, and reducing the noise in the steering mechanism part, while reducing the noise as compared to the circulation type screw screw electric steering device.

Claims (4)

In the electric steering apparatus including a motor for supplying steering auxiliary power, A rack bar having a first screw groove on an outer circumferential surface thereof; A ball nut provided on an inner circumferential surface of the second screw groove facing the first screw groove, the ball nut surrounding the rack bar; A ball in contact with the first screw groove and the second screw groove; A stop portion formed in the first screw groove or the second screw groove to constrain the movement of the ball; And A non-circulating ball screw electric steering apparatus, comprising a spacer inserted between the balls and having a resilient spacer, wherein the spacer is a spherical elastic body having a full interior. In the electric steering apparatus including a motor for supplying steering auxiliary power, A rack bar having a first screw groove on an outer circumferential surface thereof; A ball nut provided on an inner circumferential surface of the second screw groove facing the first screw groove, the ball nut surrounding the rack bar; A ball in contact with the first screw groove and the second screw groove; A stop portion formed in the first screw groove or the second screw groove to constrain the movement of the ball; And A non-circulating ball screw electric steering apparatus, comprising a spacer inserted between the balls and having elasticity, wherein the spacer has a spherical shape formed of an elastic body and a rigid body inside. In the electric steering apparatus including a motor for supplying steering auxiliary power, A rack bar having a first screw groove on an outer circumferential surface thereof; A ball nut provided on an inner circumferential surface of the second screw groove facing the first screw groove, the ball nut surrounding the rack bar; A ball in contact with the first screw groove and the second screw groove; A stop portion formed in the first screw groove or the second screw groove to constrain the movement of the ball; And A non-circulating ball screw electric steering device, comprising: a spacer inserted between the balls and having a resilient spacer, wherein the spacer is an elastic body having a hollow spherical shape. 4. The method according to any one of claims 1 to 3, The spacer is formed less than 0.01 ~ 0.09 mm than the diameter of the ball, the non-cyclic ball screw electric steering device, characterized in that the spacer and the ball are alternately arranged.

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