KR101382034B1 - Reducer of Electric Power Steering Apparatus - Google Patents

Abstract

The present invention relates to a speed reducer of an electric power assisted steering device.
According to one embodiment of the invention, the worm shaft and the drive shaft of the motor is connected to the damping coupler to transmit power, the damping coupler, the central portion is connected to the worm shaft, the shaft spline coupled to the elastic body around the outer peripheral surface; And a pipe spline having a central portion connected to the drive shaft, and the shaft spline interpolated, wherein a portion of the shaft spline or a portion of the pipe spline is provided as a magnetic part. Is provided.
According to the embodiment of the present invention, there is an effect of preventing the generation of rattle noise between the worm shaft and the shaft spline.

Description

Reducer of electric power assisted steering system {Reducer of Electric Power Steering Apparatus}

The present invention relates to a speed reducer of an electric power assisted steering device, and more particularly, to maintain the assembly between the worm shaft and the damping coupler, to improve the adhesion between the worm shaft and the shaft spline after assembly to prevent the occurrence of rattle noise, pipe A speed reducer of an electric power assisted steering device is provided to cushion an axial shock between a spline and a shaft spline to prevent a shock from being transmitted to a motor.

1 is a cross-sectional view showing a reducer of a conventional electric power assisted steering device.

As shown in FIG. 1, the speed reducer of the electric power assisted steering device includes a motor 130, a drive shaft 205, a shaft spline 220, a pipe spline 215, an elastic body 210, a first bearing 250, and a worm shaft. 235, worm gear 245, second bearing 270, compression screw 255, compression spring 265, and gear housing 260.

Motor 130 has a drive shaft 205 extending to the outside, the pipe spline 215 is hollow inside and one side is connected to the drive shaft 215 is interlocked. The second bearing 270 and the first bearing 250 fix the worm gear 245 in the direction of the worm wheel gear 240 installed on the steering shaft 102. The compression spring 265 supports the worm gear 245 in the direction of the worm wheel gear 240 by the compression screw 255, and supports the second bearing 270. Accordingly, when the compression screw 255 is tightened, the compression screw 255 is moved to constrict the compression spring 265. As a result, the worm gear 245 is firmly bitten with the worm wheel gear 240 by the compression force of the compression spring 265. Can be.

The shaft spline 220 is connected to the worm shaft 235, and the shaft spline 220 has a structure in which one side is inserted into the pipe spline 215 connected to the driving shaft 205.

2 is an exploded perspective view showing a part of a reducer of a conventional electric power assisted steering device.

As shown in FIG. 2, the speed reducer of the electric power assisted steering device includes a damping coupler 360 including a pipe spline 215, an elastic body 310, and a shaft spline 220, and a boss 320 connected to an end of the driving shaft 205. And a worm shaft 235, the pipe spline 215 has a structure capable of interpolating the shaft spline 220, and an elastic body 310 is disposed between the shaft spline 220 and the pipe spline 215. It is provided. In addition, the shaft spline 220 is drilled with a hole 345 in which axial serrations are formed, and the opposite serration 350 is connected to the machined worm shaft 235, and the serration-formed hole (not shown) is formed. The pipe spline 215 is connected to the boss 320 having the axial serration 342 formed on the outer circumferential surface thereof, and the boss 320 having the hole 340 having the axial serration formed therein is a drive shaft of the motor. And 205.

By the way, the speed reducer of the conventional electric power assisted steering device prevents rattle noise by applying grease between the worm shaft and the shaft spline, but the amount of grease applied is insufficient or the grease applied is applied. If lost, there was a problem that the rattle noise occurs.

The present invention has been made in view of the above-mentioned background, while maintaining the assembly between the worm shaft and the damping coupler, the purpose is to improve the adhesion between the worm shaft and the shaft spline after assembly to prevent the occurrence of rattle noise.

In addition, an object of the present invention is to insert an elastic plate between the pipe spline and the shaft spline, so that even if the worm shaft is spaced in the axial direction, the elastic plate to mitigate the impact to prevent the shock is transmitted to the motor.

The objects of the present invention are not limited thereto, and other objects not mentioned may be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, the worm shaft and the drive shaft of the motor is connected to the damping coupler to transmit power, the damping coupler, the central portion is connected to the worm shaft, the shaft spline coupled to the elastic body around the outer peripheral surface; And a pipe spline having a central portion connected to the drive shaft, and the shaft spline interpolated, wherein a portion of the shaft spline or a portion of the pipe spline is provided as a magnetic part. May be provided.

In addition, the shaft spline, a hole in which the worm shaft is fixed is formed in the center, and has a structure in which the protrusions projected in the radial direction with respect to the center of the hole, any one or more of the protrusions provided as the magnetic portion A reducer of the electric power assisted steering device may be provided.

In addition, the shaft spline is divided into two based on the axial direction, any one of which may be provided with a reducer of the electric power assist steering device, characterized in that provided with the magnetic portion.

In addition, the pipe spline, the central portion is formed with a hole; And an accommodating part integrally formed with the extension part and having an open structure at one side thereof, wherein the shaft spline is interpolated, wherein at least two parts of the accommodating part in the axial direction are provided as the magnetic part. A reducer of the electric power assisted steering device may be provided.

And an elastic plate is further inserted between the axial one side of the shaft spline and the inner surface of the pipe spline facing the one side to relieve the axial impact between the shaft spline and the pipe spline. The reducer of the power assisted steering may be provided.

According to the embodiment of the present invention, there is an effect of preventing the generation of rattle noise between the worm shaft and the shaft spline.

In addition, according to an embodiment of the present invention, by inserting the elastic plate between the pipe spline and the shaft spline, even if the worm shaft is spaced in the axial direction, there is an effect that the elastic plate to mitigate the impact to prevent the shock is transmitted to the motor.

1 is a cross-sectional view showing a reducer of a conventional electric power assisted steering device;
2 is an exploded perspective view showing a portion of a reducer of a conventional electric power assisted steering device;
3 is an exploded perspective view showing a part of a reducer of the electric power assisted steering apparatus according to the embodiment of the present invention;
4 is a perspective view showing the shaft spline of FIG. 3;
5-7 show various embodiments of the shaft spline of FIG. 4;
8 is a cross-sectional view illustrating a damping coupler structure of a reducer of the electric power assisted steering apparatus according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in 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 describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

Figure 3 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the embodiment of the present invention. 4 is a perspective view illustrating the shaft spline of FIG. 3.

Referring to FIG. 3, the speed reducer of the electric power assisted steering apparatus according to the embodiment of the present invention includes a damping coupler 560 having a shaft spline 510, a pipe spline 530, and an elastic plate 570. .

The shaft spline 510 has a central portion connected to the worm shaft 235, a portion of which is provided as a magnetic portion 515a, and an elastic body 511 is coupled around an outer circumferential surface thereof. A hole 513 is formed at the center of the shaft spline 510, and a serration is formed in the circumferential direction of the inner circumferential surface of the hole 513, and the serration 350 is formed in the hole 513. The end is inserted. The worm shaft 235 is formed of a material that reacts to a magnet such as steel. By forming a portion of the shaft spline 510 as the magnetic portion 515a, the worm shaft 235 inserted into the hole 513 is pulled toward the magnetic portion 515a, and thus, between the worm shaft 235 and the hole 513. Since adhesion is improved, rattle noise between the worm shaft 235 and the shaft spline 510 may be prevented. Meanwhile, the gap between the worm shaft 235 and the worm wheel 240 (see FIG. 1) may be caused by the attraction force between the magnetic portion 515a of the shaft spline 510 and the pipe spline 530 made of a material such as steel. However, this is offset by the restoring force of the elastic body 511 provided between the pipe spline 530 and the shaft spline 510.

The shaft spline 510 has a portion thereof as a magnetic part. Referring to FIG. 4, the shaft spline 510 has a structure in which three protrusions 515b, 515c, and 515d and one magnetic part 515a protrude radially from the center of the hole 513. At this time, the magnetic portions 515a are sequentially formed with the N pole and the S pole in the axial direction, and the three protrusions 515b, 515c, and 515d are formed with nonmagnetic portions. The magnetic part 515a and the nonmagnetic parts 515b, 515c, and 515d may be separately manufactured and then integrally formed by a welding method, an adhesive method, or the like.

5 through 7 illustrate various embodiments of the shaft spline of FIG. 4.

Referring to FIG. 5, the shaft spline 610 is formed in a structure in which three protrusions 615b, 615c, and 615d and one magnetic part 615a protrude radially from the center of the hole 613. The magnetic portions 615a are sequentially formed with the N pole and the S pole in the circumferential direction, and the three protrusions 615b, 615c, and 615d are formed as nonmagnetic portions.

Referring to FIG. 6, the shaft spline 710 is divided into two parts so as to be symmetrical with respect to the axial direction, and is divided into the magnetic part 715a and the nonmagnetic part 715b, and the magnetic part 715a is N pole and S in the axial direction. The poles are formed sequentially.

Referring to FIG. 7, the shaft spline 810 is divided into two parts so as to be symmetrical with respect to the axial direction, and is divided into a magnetic part 815a and a nonmagnetic part 815b, and the magnetic part 815a is N pole and S in the circumferential direction. The poles are formed sequentially.

Referring back to FIG. 3, an elastic body 511 is coupled around an outer circumferential surface of the shaft spline 510. The elastic body 511 mitigates the impact between the shaft spline 510 and the pipe spline 530 when the shaft spline 510 is spaced in the radial direction. A hole 513 is formed in the center of the shaft spline 510 to form a serration in the axial direction and is connected to the worm shaft 235 in which the serration 350 is formed.

The pipe spline 530 has a structure in which a central portion thereof is connected to the driving shaft 205 and the shaft spline 510 is interpolated. The pipe spline 530 is formed of a material that reacts to a magnet such as steel. The pipe spline 530 includes an extension 531 and a receiving portion 533. Extension portion 531 has a cylindrical shape with a hole (not shown) in the center. An axial serration is formed in a hole (not shown) of the extension part 531, and a boss (an axial serration 342) is formed in an outer circumferential surface of the hole (not shown) of the extension part 531 so as to correspond thereto. 320) is inserted. The boss 320 is connected to the drive shaft 205 of the motor. The accommodating part 533 is integrally formed with the extension part 531 and has a structure in which one side is open, and an outer circumferential surface of the elastic body 511 is bent so that the shaft spline 510 with the elastic body 511 can be interpolated. It is provided in the shape corresponding to the.

The elastic plate 570 is inserted between the axial one side of the shaft spline 510 and the inner side of the pipe spline 530 facing the one side. The elastic plate 570 mitigates the axial impact between the shaft spline 510 and the pipe spline 530. To this end, the elastic plate 570 is formed of various materials that can mitigate impact such as rubber or plastic. By inserting the elastic plate 570 between the shaft spline 510 and the pipe spline 530 in this way, even if the worm shaft 235 is spaced in the axial direction, the elastic plate 570 mitigates the impact and thus impacts the motor 130. This can be prevented from being delivered.

8 is a cross-sectional view illustrating a damping coupler structure of a reducer of the electric power assisted steering apparatus according to another embodiment of the present invention.

Referring to FIG. 8, the accommodating portion 633 of the pipe spline, which is a portion corresponding to the accommodating portion 533 of the pipe spline 530 of FIG. 3, has the magnetic portions 635a and the nonmagnetic portions 635b, 635c, and 635d. ) For example, when the magnetic part 635a is divided into four parts in the axial direction, the magnetic part 635a may correspond to one part thereof, and the other part may be the nonmagnetic parts 635b, 635c, and 635d. In this case, the polarity of the magnetic part 635a may be the same as the polarity of the magnetic part 515a of the shaft spline 510 of FIG. 4 or the polarity of the magnetic part 615a of the shaft spline 610 of FIG. 5. have.

In contrast, when the magnetic part is divided into two parts in the axial direction, the magnetic part corresponds to one of them, and the other part may be a nonmagnetic part. In this case, the polarity of the magnetic part may be the same as that of the magnetic part 715a of the shaft spline 710 of FIG. 6 or the polarity of the magnetic part 815a of the shaft spline 810 of FIG. 7. In addition, although the case where the accommodating part 633 of the pipe spline was divided into four or two was mentioned above, it is not limited to this.

As such, by forming the magnetic portion 635a in the receiving portion 633 of the pipe spline, the magnetic portion 635a attracts the worm shaft 235 and the shaft spline 220 formed of a material that reacts to a magnet such as steel, and eventually, the worm shaft. Since the close contact between the 235 and the shaft spline 220, it is possible to prevent the rattle noise between the worm shaft 235 and the shaft spline 220. On the other hand, as the worm shaft 235 and the shaft spline 220 are pulled in the direction of the magnetic portion 635a by the magnetic portion 635a, the gap between the worm shaft 235 and the worm wheel 240 (see FIG. 1) may be caused. Although this may be the case, this is offset by the restoring force of the elastic body 511 provided between the receiving portion 633 and the shaft spline 220.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the components may be selectively coupled to one or more of them.

It is also to be understood that the terms such as " comprises, "" comprising," or "having ", as used herein, mean that a component can be implanted unless specifically stated to the contrary. But should be construed as including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of 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 construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

205: drive shaft 235: worm shaft
320: boss 340: hall
342: serration 350: serration
510: shaft spline 511: elastic body
513: hole 530: pipe spline
530: damping coupler 570: elastic plate

Claims (5)

By connecting the worm shaft and the drive shaft of the motor with a damping coupler to transfer power,
The damping coupler is,
A shaft spline formed at a center thereof with a hole into which the worm shaft is fixed and protruding in a radial direction based on a center of the hole, at least one of the protrusions being provided as a magnetic part and having an elastic body coupled around an outer circumferential surface thereof; And
A pipe spline having a central portion connected to the drive shaft and interleaved with the shaft spline;
Reducer of the electric power assisted steering apparatus comprising a. delete By connecting the worm shaft and the drive shaft of the motor with a damping coupler to transfer power,
The damping coupler is,
A hole in which the worm shaft is inserted and fixed is formed at the center thereof, and protrusions protrude radially based on the center of the hole, and when two or more divisions are made in the axial direction, one of them is provided as a magnetic part, and an elastic body is formed around the outer circumference. Coupled shaft splines; And
A pipe spline having a central portion connected to the drive shaft and interleaved with the shaft spline;
Reducer of the electric power assisted steering apparatus comprising a. By connecting the worm shaft and the drive shaft of the motor with a damping coupler to transfer power,
The damping coupler is,
A shaft spline having a central portion connected to the worm shaft and having an elastic body coupled around an outer circumferential surface thereof; And
An extension part having a hole formed at the center thereof and a central part connected to the driving shaft, and an accommodation part integrally formed with the extension part and having an open side, and having an shaft interpolated therein, are divided into two parts in the axial direction. When abnormal, one of the pipe spline provided with a magnetic portion;
Reducer of the electric power assisted steering apparatus comprising a. The method according to any one of claims 1, 3, and 4,
And an elastic plate is further inserted between the axial one side of the shaft spline and the inner surface of the pipe spline facing the one side to relieve the axial impact between the shaft spline and the pipe spline. Reduction gear for auxiliary steering.

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