KR100783755B1 - An Electric Type Power Steering Apparatus - Google Patents

Abstract

The present invention relates to a rack-type electric power steering apparatus, the technical configuration of which is a rack-type electric steering apparatus, the rack bar (2) in the rack housing (1) support yoke and ball nut (6) and It is configured to support the three points by the rack bush provided with a gap compensation means, the gap compensation means has a random shape on one side of the rack housing (1) and one side is formed integrally with the guide housing (10) The guide housing (10) has a guide tool (102) having a tapered surface inclined at one side, and the outer side of the rack bush (90) so as to be inclined contact with the tapered surface of the guide (102). The contact hole 92 is integrally formed to protrude integrally, the bolt 16 is elastically supported by the spring 104 from the outside of the housing to adjust the axial movement of the guide (102) to guide housing (10) Through the guide sphere 102 The main purpose is that the end face of the rack bush is configured to expand or contract according to the rotation of the bolt 106, as assembled by screwing.

According to the present invention configured as described above, it is possible to support the rack bar with a constant elastic force by compensating for the wear of the rack bushing according to the sliding support of the rack bar and the change of the support force due to temperature changes, thereby preventing noise and device defects due to play. You can do it.

3-point support, rack bar, rack bush, play compensation means

Description

Electric Power Steering Apparatus {An Electric Type Power Steering Apparatus}

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

Figure 2 is a schematic diagram showing a conventional electric power steering device configured to support three points.

Figure 3 is a schematic configuration diagram showing the overall configuration of the electric power steering apparatus according to the present invention.

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

Figure 5 is a cross-sectional view showing an operating state of the clearance compensation means of the electric power steering apparatus according to the present invention.

<Description of Signs for Major Parts of Drawings>

Guide housing

90 ... Rack Bush

92.contact

94 ... slit

102 ... Guide

104 ... Spring

106 ... Volt

The present invention relates to an electric power steering device, in particular, in the rack housing of the rack-type electric steering device, it is possible to vary the diameter of the rack bush on the rack bush side provided to support it according to the left and right sliding motion of the rack bar. The present invention relates to an electric power steering apparatus for supporting a rack bar with a constant elastic force by providing a clearance compensation structure that compensates for abrasion of a bush according to sliding support of a rack bar and a change in bearing capacity due to temperature change.

In general, a power steering system is applied to a vehicle to ensure steering stability. Among these, an electric power steering system (EPS) receives steering power from a motor to adjust steering power.

In other words, the electric power steering system drives the motor in the ECU according to the driving conditions of the vehicle detected by the vehicle speed sensor and the steering torque sensor to give a light and comfortable steering feeling at low speeds, and a good steering stability at high speeds. In the emergency situation, the steering is performed rapidly, thereby providing the driver with optimal steering conditions.

1 is a schematic cross-sectional view showing the overall configuration of the conventional general electric power steering apparatus described above.

As shown therein, a rack bar 2 having a rack gear 20 on one end of its outer circumferential surface is built in the rack housing 1, and both ends of the rack bar 2 are tie rods; 3) and the ball joint (Ball joint) is configured to transfer the transfer force of the rack bar (2).

In addition, the pinion shaft (4) is installed at one side of the rack bar having a predetermined angle inclination with the central axis of the rack bar, the pinion shaft (4) is pinched gear (not shown) is inserted into the end of the rack bar (2) It is meshed with the rack gear 20, and a support yoke (not shown) is installed at the rear of the rack gear 20 to elastically support it.

The other side of the rack housing 1 is provided with an electric motor 5 forming an acute angle or an obtuse angle with the center axis of the rack bar, and a driving bevel gear 50a is inserted into the shaft end of the electric motor 5 so that the rack housing ( 1) It engages with the driven bevel gear 60a of the outer peripheral part of the ball nut 6 which supports the other side of the rack bar 2 inside.

Here, the ball nut 6 is installed to be rotated by the ball bearing 7 in the rack housing 1, the other end of the rack bar (2) formed with a screw 22 is formed by the steel ball (8) It is made of a configuration that is supported to be sliding.

Therefore, as described above, the rack bar 2 sliding left and right inside the rack housing 1 is input from the pinion shaft with one end and the other end supported by the support yoke and the ball nut 6, respectively. The left and right sliding by receiving the driving force is to be able to change the wheel.

However, in the electric power steering device having such a configuration, the rack bar 2 is supported only at one end and the other end inside the rack housing 1, that is, only at both ends of the rack bar by the ball nut 6 and the support yoke. Since the point is supported by the left and right sliding movement, the support stiffness supporting the rack bar 2 is very low, and rocking occurs in the central recess along the left and right sliding movement of the rack bar 2. The defect that bending and deflection occurs in the center of the rack bar 2 due to the bending moment acting on the rack bar 2 through the tie rod 3 at the back of the kick-back input from the wheel there was.

Accordingly, in order to solve the above problems, an electric power steering apparatus has been known in which both ends and a center portion of a rack bar left and right slided in a rack housing are supported by a support yoke, a ball nut, and a rack bush.

That is, as shown in FIG. 2, the electric power steering apparatus as described above supports both ends of the rack bar 2 by using the support yoke 12 and the ball nut 6 in the rack housing. The rack bush 9 is configured to support three points, thereby preventing bending and sagging generated in the center of the rack bar.

However, since the conventional rack bush 9 is made of a special plastic (Hytrel) that is usually made of a natural rubber material for sliding support of the rack bar, the cross section contracts or expands in response to temperature changes, but it may react sensitively. There was no.

Nevertheless, in the related art, since there is no compensating structure for separately adjusting the cross section of the rack bush that changes according to the temperature change as described above, the rack bush is caused by frequent friction with the rack bar and play due to low temperature shrinkage. At the same time as the supporting force for supporting the rack bar is changed, noise caused by the intermittent contact with the rack bar is caused by the play.

The present invention has been made in order to improve the problems according to the conventional electric power steering device as described above, the object of the diameter of the rack bush to the rack bush side is provided to support it according to the left and right sliding movement of the rack bar. By providing a variable gap compensation structure, the rack bar can be supported with a constant elastic force by compensating for the wear of the bush and the change of bearing capacity due to the temperature change due to the sliding support of the rack bar, and at the same time, it can prevent the noise caused by the gap. An electric power steering apparatus is provided.

The present invention as a technical means for achieving the above object, the pinion connected to the steering wheel, the rack gear is built in the rack housing and is engaged with the pinion at one end is formed on one side of the rack bar, the screw formed a plurality of screws A ball nut installed to support one side of the rack bar via a steel ball, a motor installed diagonally or at right angles to the central axis of the rack bar, and a rack including gearing for transmitting power to the ball nut from the motor. In the type electric steering device, the rack bar is provided by the electric power steering device, characterized in that configured to support three points by the rack bushing provided with the support yoke, the ball nut and the clearance compensation means in the rack housing. .

In particular, the clearance compensation means of the present invention, the guide housing having an arbitrary shape is integrally formed on one side of the rack housing, the guide housing having a tapered surface inclined on one side is built in the guide housing, the rack bush outer peripheral portion On one side, a contact hole is formed to be integrally projected to be in contact with the tapered surface of the guide sphere, a bolt elastically supported by a spring from outside the housing to adjust the axial movement of the guide sphere guides through the guide housing It is assembled to screw to the sphere, characterized in that the cross section of the rack bush is configured to expand or contract according to the rotation of the bolt.

In addition, the present invention is characterized in that a slit is formed on one side of the rack bush to facilitate the cross-sectional change of the rack bush so that the cross-sectional diameter is adjusted to the play control means.

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 3 is a schematic diagram showing the overall configuration of the electric power steering apparatus according to the present invention, Figure 4 is a cross-sectional view showing a cut line A-A according to FIG.

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

As shown in FIG. 3, a rack gear 20 and a screw 22 are formed at one end and a center of the rack bar 2 in the rack housing 1, respectively, and the rack bar having the rack gear 20 formed therein ( 2) At one end, a pinion (4) connected to a steering shaft (not shown) is throttled and engaged, and a support yoke 9 is installed at the rear of the rack gear 20 to elastically support it.

The screw 22 formed at one end of the rack bar 2 is provided with a ball screw part for receiving a driving force from the motor 5 to generate an assist force for sliding the rack bar left and right.

Here, the ball screw portion, the ball nut (6) which is rotated to wrap the screw 22 of the other side of the rack bar (2) is fitted so as to rotate by the ball bearing (7) installed on the inner diameter of the rack housing (1), the ball A plurality of steel balls 8 are inserted between the nut 6 and the screw 22 of the rack bar 2 to guide the left and right sliding movements of the rack bar 2 and to support the rack bar center or end.

In particular, the rack bar 2 is added to the rack bush 2 by adding the rack bush 90 to the center thereof in the state where the rack bar 2 is supported by the ball yoke of the support yoke 9 and the ball stream portion 9 as described above. It is configured to support the rack bush 90 is characterized in that the clearance compensation structure is provided so that the cross-sectional shrinkage compensation according to the temperature change can be made.

The clearance compensation structure, the guide housing (10) having an arbitrary shape on one side of the rack housing (1) is integrally formed, the guide housing (10) can be changed in cross section of the rack housing (1) One side is formed to be separated, the guide housing (10) has a guide sphere 102 having a tapered surface inclined on one side, the outer side of the rack bush 90, the contact hole 92 is formed integrally protruding It is made to be inclined contact with the tapered surface of the guide sphere (102).

In addition, a bolt 106 for adjusting the axial movement of the guide sphere 102 in contact with the rack bush 90 penetrates the guide sphere housing 10 and has a central portion of the guide sphere 102 installed therein. It is assembled to be screwed together. At this time, the bolt 106 is elastically supported by the coil spring 104 on the outside of the guide housing 10 in order to be able to easily adjust the tightening force according to the rotation of the bolt 106.

Meanwhile, one side of the rack bush 90 is perforated with a slit 94 so that the cross-sectional diameter can be easily changed according to the axial movement of the guide tool 102.

Therefore, the operation and effects of the present invention having the above configuration will be described.

3 to 4, the electric power steering apparatus of the present invention is provided by the rack bush 90 provided with the support yoke 12 and the ball nut 6 and the clearance compensation means in the rack housing 1. Since it is configured to support three points, the support stiffness of the rack bar 2 is improved, and the kick-back that is reversely inputted through the wheels of the vehicle when the vehicle is driven may act on both ends of the rack bar 2 through the tie rods 3. When the rack bar (2) at the center of the bending (Banding) and the deflection can be prevented to improve the steering of the steering shaft connected to the steering.

In particular, the present invention is provided with a clearance compensation means in the rack bush 90, as described above, it can compensate for the cross-sectional diameter change due to the wear and temperature changes of the rack bush 90 according to the rack bar (2) support There is a rack bar (2) to be able to further improve the bearing capacity.

Figure 5 is a cross-sectional view showing an example of the clearance control process of the rack bush applied to the present invention to improve the rack bar support as described above, the clearance compensation means applied to the present invention, the rack bush (90) to support the rack bar (2) When the rack is worn out due to sliding friction with the rack bar 2 or contracted or expanded due to temperature (cold) change, the cross-sectional diameter of the rack bush 90 can be adjusted by the bolt 106 to compensate for the support of the rack bar. Will be.

In detail, as shown in FIG. 5, when the bolt 106 is turned clockwise (the direction in which the guide sphere is tightened to the bolt), the bolt 106 and the threaded guide sphere 102 are tightened to the bolt 106. It is moved to one side (in the direction of the arrow in the drawing), at this time the tapered surface of the guide sphere 102 is in contact with the outer peripheral surface of the contact portion 92 of the rack bush 90, the contact portion in accordance with the movement of the guide sphere 102 As the 92 is compressed, the rack bush 90 is able to shrink in section.

At the same time, the guide housing extended to the rack housing 1 is also configured to allow the cross-section shrinkage by the above-described bolt 106, so that the rack bush 90 as the cross section is contracted to support it from the outside. Cross section of the rack housing (1) is also to be contracted to compensate for the rack bar (2) bearing capacity.

Here, as described above, since the slit 94 is drilled in one end surface of the rack bush 90 to which the cross section is reduced by the clamping force of the bolt 106, the cross section shrinkage of the rack bush 90 can be easily performed. Will be.

That is, the present invention is able to vary the cross-sectional diameter of the rack bush 90, which is elastically supporting the rack bar (2) in the rack housing (1), thereby compensating for the support force of the rack bar that changes with temperature changes and wear It is possible to prevent the malfunction of the device in advance.

As described above, according to the electric power steering of the present invention, the rack bar is provided on the rack bush side provided to support the rack bar according to the left and right sliding motion of the rack bar, thereby allowing the rack bush to have a variable diameter of the rack bush. By compensating for the wear of the bush according to the sliding support and the change in the bearing capacity according to the temperature change, the rack bar can be supported with a constant elastic force, thereby preventing noise and device defects due to play.

While the invention has been shown and described with respect to particular embodiments, it will be appreciated that the invention can be modified and modified in various ways without departing from the spirit or scope of the invention as set forth in the claims below. It will be appreciated that those skilled in the art can easily know.

Claims (3)

The pinion (4) connected to the steering wheel, the rack housing (1), which is built into the rack gear 20 is engaged with the pinion (4) at one end, the rack bar (2) formed with a screw 22 on one side, the screw Ball nut 6 installed to support one side of the rack bar via a plurality of steel balls (8), the motor (5) installed at an angle or perpendicular to the central axis of the rack bar (2), the In the rack type electric steering device comprising a gear ring (100) for transmitting power from the motor (5) to the ball nut (6); The rack bar (2) is an electric power characterized in that it is configured to support three points by the rack bush (90) provided with the support yoke (9), the ball nut (6) and the clearance compensation means in the rack housing (1) Steering device. The method of claim 1, The gap compensation means, the rack housing (1) has an arbitrary shape and is formed integrally with a guide sphere housing 10 cut one side, the guide sphere housing 10 has a tapered surface inclined to one side A guide tool 102 having a built-in, the outer side of the rack bush 90, the contact hole 92 to be inclined contact with the tapered surface of the guide tool 102 is formed integrally projecting, the guide tool ( A bolt 106 elastically supported by the spring 104 on the outside of the housing to adjust the axial movement of the 102 passes through the guide housing 10 and is screwed into the guide opening 102 so that the bolt 106 is assembled. Electric power steering device, characterized in that the cross section of the rack bush 90 is configured to expand or contract according to the rotation of the). The method of claim 2, The rack bush (90) is an electric power steering device, characterized in that the slit (94) is formed so that the cross-sectional diameter can be easily adjusted.

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