KR102369862B1 - Reducer of Electric Power Steering Apparatus - Google Patents

Abstract

The present embodiments relate to a reducer of an electric power-assisted steering device. According to the present embodiments, a worm shaft meshing with a worm wheel is built-in, and a guide hole is formed in a slit shape along the vertical direction at the end opposite to the motor coupling part. A clearance compensating member rotatably coupled to the housing and gear housing and having a guide hole formed in a slit shape to be spaced apart from the center of rotation, coupled to the outer circumferential surface of the worm shaft bearing coupled to the end opposite to the motor shaft coupling portion of the worm shaft, the guide hole and The reduction gear of the electric power-assisted steering device including a support member in which a support protrusion passing through the guide hole protrudes in an axial direction from an end opposite to the worm shaft coupling portion may be provided.

Description

Reducer of Electric Power Steering Apparatus

The present embodiments relate to a reducer of an electric power-assisted steering system, and more particularly, by minimizing the amount of change in play due to a change in the rotational torque of the worm shaft, noise and vibration generated in the worm shaft can be eliminated, and the steering wheel operation can be accurately supported. It is related to the reducer of the electric power assisted steering system.

In general, the reducer of the electric power assist steering system controls the driving of the motor provided in the reducer by the electronic control device provided in the vehicle according to the vehicle operating conditions, and the rotational force of the worm shaft by the driving of the motor is controlled by the driver through the worm wheel. It is transmitted to the steering shaft in addition to the rotational force of the steering wheel to be operated, so that the driver's steering operation state can be maintained smoothly and stably.

However, the conventional reducer of the electric power-assisted steering system has problems in that manufacturing errors and assembly errors are accumulated at the coupling portion of the worm shaft and the motor shaft, causing a feeling of jamming of the bearing and increasing the rotational resistance of the worm shaft.

In addition, when the durability of the worm and the worm wheel progresses, there is a problem that play occurs due to wear and rattle noise is generated due to backlash. There was a problem that caused discomfort.

The present embodiments were devised in the background described above, and by minimizing the amount of change in play according to the change in the rotational torque of the worm shaft, the noise and vibration generated in the worm shaft are eliminated, and the electric power assist steering device capable of accurately assisting the steering wheel operation. The purpose is to provide a speed reducer.

The purpose of the present embodiments is not limited thereto, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve this object, the present embodiments have a built-in worm shaft that meshes with the worm wheel, and a guide hole at the opposite end of the motor coupling portion is rotatably coupled to a gear housing and a gear housing in which a slit shape is formed along the vertical direction, A play compensating member in which a guide hole is formed in a slit shape to be spaced apart from the rotation center, is coupled to the outer peripheral surface of a worm shaft bearing coupled to an end opposite to the motor shaft coupling part of the worm shaft, and a support protrusion passing through the guide hole and the guide hole is a worm shaft coupling part There may be provided a reducer of the electric power-assisted steering device including a support member protruding in the axial direction at an opposite end thereof.

According to these embodiments, when the play increases due to wear of the worm shaft and the worm wheel, the worm shaft is elastically supported in the worm wheel direction by the play compensating member, thereby minimizing the amount of change in the play according to the change in the rotational torque, thereby reducing the driver's steering wheel. It has the effect of accurately assisting the manipulation force.

1 is a perspective view showing a part of a speed reducer of an electric power assist steering device according to the present embodiments;
2 is an exploded perspective view showing a part of a reducer of the electric power assist steering device according to the present embodiments;
3 is a side cross-sectional view showing a part of the reducer of the electric power assist steering system according to the present embodiments;
4 to 6 are front views illustrating a structure in which the worm shaft is elastically supported in the worm wheel direction by the support member as the clearance compensating member of the electric power assist steering apparatus according to the present embodiments rotates in one direction.

Hereinafter, some embodiments of the present embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in the description of the present embodiments, if it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present embodiments, the detailed description thereof will be omitted.

Also, in describing the components of the present embodiments, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When an element is described as being "connected", "coupled" or "connected" to another element, the element may be directly connected or connected to the other element, but another element may exist between each element. It should be understood that elements may be “connected,” “coupled,” or “connected.”

1 is a perspective view showing a part of the reducer of the electric power-assisted steering system according to the present embodiments, FIG. 2 is an exploded perspective view showing a part of the reducer of the electric power-assisted steering system according to the present embodiments, and FIG. 3 is this embodiment 4 to 6 are side cross-sectional views showing a part of the reducer of the electric power-assisted steering system according to the present embodiment, as the play compensating member of the electric power-assisted steering system according to the present embodiments rotates in one direction, the worm shaft moves in the worm wheel direction by the support member It is a front view showing the elastically supported structure.

As shown in these figures, the reducer of the electric power assist steering device according to the present embodiments has a built-in worm shaft 254 meshing with the worm wheel 156, and a guide hole 410 at the opposite end of the motor coupling part. The gear housing 400, which is formed in a slit shape along the vertical direction, is rotatably coupled to the gear housing 400, and the guide hole 350 is formed in a slit shape to be spaced apart from the rotation center 300. , coupled to the outer circumferential surface of the worm shaft bearing 257a coupled to the opposite end of the motor shaft coupling portion of the worm shaft 254, the support protrusion 510 penetrating the guide hole 350 and the guide hole 410 is the worm shaft 254 It includes a support member 500 that is formed to protrude in the axial direction at the opposite end of the coupling portion.

The reducer of the electric power assist steering device according to the present embodiments is provided with a worm shaft 254 having a worm 152 formed on an outer peripheral surface thereof, and the worm shaft bearings 257a and 257b supporting the worm shaft 254 are of the worm shaft 254 . A plug bolt 210 that is installed at both ends and is fixed by a plug nut 220 in order to prevent the worm shaft 254 from being axially spaced is fastened between the damping coupler 240 and the worm shaft bearing 257b. .

Here, a worm wheel 156 is provided on one side of the outer diameter of the worm 152 so as to be engaged with the worm 152 formed on the worm shaft 254, and the worm wheel 156 is a steering shaft of a steering wheel operated by a driver ( It is mounted on the 106 and transmits the rotational force of the worm shaft 254 by driving the motor to the steering shaft 106 .

1 to 3, the gear housing 400 has a built-in worm shaft 254 that meshes with the worm wheel 156, and the guide hole 410 at the opposite end of the motor coupling portion has a slit shape along the vertical direction. is formed with

The worm shaft bearings 257a and 257b are respectively coupled to both ends of the worm shaft 254 and are supported on the inner surface of the gear housing 400 to support the worm shaft 254 .

And, the clearance compensation member 300 is rotatably coupled to the gear housing 400 as shown in FIGS. 4 to 6 , and the guide hole 350 is formed in a slit shape to be spaced apart from the rotation center.

The clearance compensation member 300 has an inner portion 340 in which the guide hole 350 through which the support protrusion 510 penetrates is formed in a slit shape to be spaced apart from the center of rotation, and the inner portion 340 in a shape surrounding the inner portion 340 and A plurality of support parts 330 formed between the outer part 320 and the inner part 340 and the outer part 320 which are formed to be spaced apart from each other at a predetermined distance and supported by the outer part 320 to elastically support the inner part 340 are included. do.

The inner part 340 is formed in a disk shape, and the guide hole 350 through which the support protrusion 510 passes is formed in a slit shape to be spaced apart from the rotation center.

In addition, the outer portion 320 is formed in a cylindrical shape surrounding the inner portion 340, and is formed on the outside of the inner portion 340 in a state spaced apart from the inner portion 340 at a predetermined interval.

The support part 330 is supported by the outer part 320 and is formed between the inner part 340 and the outer part 320 to elastically support the inner part 340, and a plurality of them are radially spaced apart from the inner part 340 at a predetermined interval. It protrudes and is connected to the outer part 320 .

The support portion 330 may include a primary bent portion extending radially outward from the inner portion 340; Doedoe extending from the first bent portion, the second bent portion bent at an obtuse or acute angle in the longitudinal direction of the first bent portion without parallel with the first bent portion, is formed extending from the second bent portion, the outer part 320 It is connected to, and includes a tertiary bend bent at an obtuse or acute angle in the longitudinal direction of the secondary bend so as to be parallel to the first bend.

A plurality of such support portions 330 are formed between the outer portion 320 and the inner portion 340 to be spaced apart from each other at regular intervals along the circumferential direction so that the force supporting the inner portion 340 is not inclined to either side, and the inner portion 340 ) is elastically supported.

Accordingly, the clearance compensation member 300 can elastically support the worm shaft 254 toward the worm wheel when clearance occurs due to wear of the worm shaft 254 and the worm wheel 156 .

The inner part 340, the outer part 320, and the support part 330 are NR (Natural Rubber), NBR (Nitrile Butadiene Rubber), CR (Chloroprene Rubber), EPDM (Ethylene Propylene Terpolymer), FPM to have weather resistance and elasticity. It may be formed of an elastic material such as (Fluoro Elastomer), SBR (Styrene Butadine Rubber), CSM (Chlorosulphonated Polyethylene), silicone, or urethane.

In addition to this, the clearance compensation member 300 has a shape surrounding the outer part 320 , the outer part 320 is fitted therein, and a rigidity supplemental ring 310 that is rotatably coupled to the gear housing 400 .

The rigidity supplement ring 310 is rotatably coupled to the gear housing 400 in a cylindrical shape surrounding the outer part 320, and the outer part 320 is fitted therein.

The rigidity supplementing ring 310 is made to have greater rigidity than the outer portion 320 to prevent the shape of the outer portion 320 from being deformed.

At this time, the rigidity supplement ring 310 is an engineering plastic-based material such as polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), etc. It may be formed of or may be formed of a metal material such as steel.

In addition, the support member 500 is coupled to the outer peripheral surface of the worm shaft bearing 257a coupled to the opposite end of the motor shaft coupling portion of the worm shaft 254, and a support protrusion passing through the guide hole 350 and the guide hole 410 ( 510 is formed to protrude in the axial direction at the opposite end of the worm shaft 254 coupling portion.

That is, the support member 500 is formed in a cylindrical shape with one side closed, and a worm shaft bearing 257a coupled to an end opposite to the motor shaft coupling portion of the worm shaft 254 is fitted and coupled therein, and the worm shaft 254 is coupled. A support protrusion 510 penetrating through the guide hole 350 and the guide hole 410 is formed to protrude in the axial direction on one side of the sealed end opposite to the site.

The support member 500 moves in the vertical direction along the guide hole 410 by the rotation of the clearance compensation member 300 to adjust the clearance between the worm shaft 254 and the worm wheel 156 .

That is, in the support member 500, the gap compensation member 300 is moved in one direction by the support protrusion 510 penetrating through the guide hole 350 of the gap compensation member 300 and the guide hole 410 of the gear housing 400. Alternatively, when rotating in the opposite direction, the support protrusion 510 moves vertically along the guide hole 410 to rotate the worm shaft 254 .

4 to 6, the worm shaft 254, in which the worm shaft bearings 257a and 257b and the support member 500 are coupled to mesh with the worm wheel 156, are assembled to the gear housing 400, and clearance compensation After assembling the member 300 to the gear housing 400 so that the guide hole 350 is located in the lateral direction and rotating it in one direction or the opposite direction, the support protrusion 510 moves downward along the guide hole 410 It moves and rotates the worm shaft 254 .

As such, as the support protrusion 510 moves from L1 to L2 in the downward direction along the guide hole 410, the worm shaft 254 is coupled to the end of the motor shaft coupling portion of the worm shaft 254. The worm shaft bearing 257b ), it is possible to adjust the clearance between the worm shaft 254 and the worm wheel 156 by rotating in the lower direction.

At this time, the worm shaft bearing 257b coupled to the end of the motor shaft coupling portion of the worm shaft 254 is coupled to the outer periphery of the end coupled to the motor shaft among both ends of the worm shaft 254, and a plurality of rolling members are rolled on the outer circumferential surface. an inner ring in contact; an outer ring in which a plurality of rolling members are in rolling contact with the inner circumferential surface corresponding to the inner ring, and the convex portions on the outer circumferential surface are formed in a convex curved surface going from both ends in the axial direction to the central portion; and a guide ring member in which a concave portion is formed in a curved surface concave on the inner circumferential surface corresponding to the convex portion of the outer ring so as to be in spherical contact with the outer ring.

Accordingly, the inner ring and the outer ring rotate freely along the spherical surface of the convex portion and the concave portion inside the guide ring member.

Accordingly, when the clearance is increased due to wear of the worm shaft 254 and the worm wheel 156, the worm shaft 254 is rotated at a predetermined angle in the vertical direction by the clearance compensation member 300. It is possible to accurately assist the driver's steering wheel operation force by minimizing the amount of change in play.

According to the present embodiments having such a shape and structure, when the play increases due to wear of the worm shaft and the worm wheel, the worm shaft is elastically supported in the worm wheel direction by the play compensating member, thereby minimizing the amount of change in play due to the change in rotational torque. This has the effect of accurately assisting the driver's steering wheel operation force.

In the above, even though it has been described that all components constituting the present embodiments are combined or operated as one, the present embodiments are not necessarily limited to these embodiments. That is, within the scope of the purpose of the present embodiments, all of the components may operate by selectively combining one or more.

The above description is merely illustrative of the technical idea of the present embodiments, and various modifications and variations are possible without departing from the essential characteristics of the present embodiments by those skilled in the art to which the present embodiments belong. will be. Therefore, the embodiments disclosed in the present embodiments are for explanation rather than limiting the technical spirit of the present embodiments, and the scope of the technical spirit of the present embodiments is not limited by these embodiments. The protection scope of the present embodiments should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiments.

106: steering shaft 156: worm wheel
254: worm shaft 257: worm shaft bearing
260: gear housing 300: play compensation member
310: rigidity supplemental ring 320: outer part
330: support 340: inner part
350: guide hole 400: guide hole
500: support member 510: support protrusion

Claims (5)

a gear housing having a built-in worm shaft meshing with the worm wheel, and having a guide hole formed in a slit shape along the vertical direction at an end opposite to the motor coupling part;
a clearance compensating member rotatably coupled to the gear housing and having a guide hole formed in a slit shape to be spaced apart from the center of rotation;
a support member coupled to an outer circumferential surface of a worm shaft bearing coupled to an end opposite to the motor shaft coupling portion of the worm shaft, wherein a support protrusion penetrating the guide hole and the guide hole protrudes in an axial direction from the opposite end of the worm shaft coupling portion;
A reducer of an electric power assist steering system comprising a. The method of claim 1,
The support member moves up and down along the guide hole by rotation of the clearance compensation member, and adjusts the clearance between the worm shaft and the worm wheel. The method of claim 1,
The clearance compensating member,
an inner portion in which the guide hole through which the support protrusion passes is formed in a slit shape to be spaced apart from the center of rotation;
an outer portion formed to be spaced apart from the inner portion in a shape surrounding the inner portion;
a plurality of support parts formed between the inner part and the outer part and supported by the outer part to elastically support the inner part;
A reducer of an electric power assist steering system comprising a. 4. The method of claim 3,
The support part,
a primary bent portion extending radially outward from the inner portion;
a secondary bent part extending from the primary bent part and bent at an obtuse or acute angle in the longitudinal direction of the primary bent part while not parallel to the primary bent part;
a tertiary bent part extending from the secondary bent part and connected to the outer part, the tertiary bent part being bent at an obtuse or acute angle in the longitudinal direction of the secondary bent part so as to be parallel to the primary bent part;
A reducer of an electric power assist steering system comprising a. 4. The method of claim 3,
The clearance compensating member,
The reduction gear of the electric power-assisted steering device, characterized in that it includes a rigidity supplementary ring that is fitted inside the outer portion in a shape surrounding the outer portion, and is rotatably coupled to the gear housing.

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