KR20110008716A - Reducer of electronic power steering apparatus - Google Patents

Abstract

PURPOSE: A reducer of an electronic power steering device is provided to accurately assist a driver when the driver steers a steering wheel and to reduce impact sound transferred from a road surface. CONSTITUTION: A reducer of an electronic power steering device comprises a worm shaft bearing(257), a stopper(350), a holder(320), a holder cap(310), and an elastic supporter(330). The worm shaft bearing is coupled to a worm shaft(254). The stopper prevents the worm bearing from being separated from the worm shaft. A coupling hole(325) is formed at the center of the holder so that the holder can be coupled to the end of the worm shaft. The holder and the stopper are inserted intot he holder cap, and the holder cap is coupled to the inner end of a gear housing. The elastic supporter is coupled between the inner surface of the holder cap and the holder and supports the holder toward a worm wheel.

Description

Reducer of Electronic Power Steering Apparatus

The present invention relates to a speed reducer of an electric power assisted steering device. More specifically, in the reducer of the electric power assisted steering device, it prevents the play caused by the wear of the worm and the worm wheel, reduces the impact noise and the rattle noise caused by the backlash from the road surface, and minimizes the amount of play caused by the change of the rotation torque. The present invention relates to a speed reducer of an electric power assist steering device capable of accurately assisting a driver's steering wheel operating force.

1 is a configuration diagram of a conventional electric power assisted steering device, as shown in FIG. 1, the electric power assisted steering device 100 includes a steering system 130 and steering which extends from the steering wheel 102 to both wheels 126. And an auxiliary power mechanism 140 that provides steering assistance power to the system 130.

Steering system 130 is a steering shaft 106, one side is connected to the steering wheel 102 to rotate together with the steering wheel 102 and the other side is connected to the pinion shaft 108 via a pair of universal joint 104 It is configured to include). In addition, the pinion shaft 108 is connected to the rack bar 112 through the rack-pinion mechanism unit 110, and both ends of the rack bar 112 are connected to the wheels 126 of the vehicle through the tie rods 122 and the knuckle arm 124. )

The auxiliary power mechanism 140 senses torque applied to the steering wheel 102 by the driver and outputs an electrical signal proportional to the detected torque based on the electrical signal transmitted from the torque sensor 142 and the torque sensor 142. The steering shaft 106 controls the electronic control device 144 that generates the control signal, the motor 146 that generates auxiliary power based on the control signal transmitted from the electronic control device 144, and the auxiliary power generated by the motor 146. It comprises a reducer 150 having a worm 152 and a worm wheel 156 for delivery to.

Accordingly, in the electric power assist steering device, torque generated by the rotation of the steering wheel 102 is transmitted to the rack bar 112 via the rack-pinion mechanism unit 110, and the assist power generated in the motor 146 according to the generated torque. It is configured to be delivered to the rack bar 112.

That is, the torque generated by the rotation of the steering wheel 102 and the auxiliary power generated by the motor 146 are combined to move the rack bar 112 in the axial direction.

2 is a cross-sectional view showing a reducer of a conventional electric power assisted steering device. As shown in FIG. 2, the reducer 150 includes a worm shaft 254 having a worm 152 formed thereon, and a worm shaft bearing at both ends of the worm shaft 254. 257 are respectively installed to support the worm shaft 254, the plug bolt 210 is damped coupler 240 and the worm shaft bearing in order to prevent the worm shaft bearing 257 is spaced in the axial direction of the worm shaft 254 ( 257, and the plug bolt 210 is fixed by the plug nut 220.

The worm shaft 254 has a structure in which the worm shaft 254 is rotated by the driving of the motor 146 by connecting the motor 146 and the damping coupler 240 as a medium.

And the worm wheel 156 is provided on one side of the outer diameter of the worm 152 so that the worm 152 formed on the worm shaft 254, the worm wheel 156 is a rotational force of the steering wheel 102 that the driver can operate Is mounted on the steering shaft 106 to transmit the rotational force of the worm shaft 254 by the drive of the motor 146 is a structure that is transmitted to the steering shaft 106.

The gear housing 260 includes a motor 146 which is provided with a worm 152, a worm wheel 156, and the like, and provides a driving force to the worm shaft 254 on one side of the gear housing 260. Motor 146 is coupled to bolt 250 by motor cover 230.

The worm shaft bearing 257 has a ball 258 coupled between the inner ring 280 and the outer ring 270 to support rotation of the worm shaft 254 connected to the motor 150 at the end of the gear housing 260. do.

The speed reducer of the electric power assisted steering device having such a structure controls the driving of the motor by an electronic control device provided in the vehicle according to the vehicle driving conditions, and the rotational force of the worm shaft by the driving of the motor controls the steering wheel of the driver. In addition to the rotational force is transmitted to the steering shaft, so that the steering operation state of the driver can be kept smooth and stable.

However, the reducer of the conventional electric power assist steering device has a problem in that noise is generated due to play caused by wear when the worm and the worm wheel rotated by the driving of the motor.

In addition, there is a problem that the noise generated by the impact sound and the backlash of the worm and worm wheel transmitted from the wheel and the steering shaft from the road surface.

Therefore, due to such problems, there is also a problem in that it is not possible to accurately provide a steering assistance force for assisting a driver's steering wheel manipulation force.

Accordingly, the present invention has been made to solve the above problems, in the reducer of the electric power assist steering device, to prevent the play by the wear of the worm and the worm wheel and to reduce the rattle noise by the impact sound and backlash transmitted from the road surface, It is an object of the present invention to provide a speed reducer of an electric power assist steering device that can accurately assist a driver's steering wheel operating force by minimizing the amount of play caused by a change in rotational torque.

In order to achieve this object, an embodiment of the present invention includes a worm shaft bearing coupled to the opposite end of the motor shaft coupling portion of the worm shaft; In order to prevent the worm shaft bearing from being separated, one side is provided with a large diameter portion open to the motor shaft coupling portion to which the outer ring of the worm shaft bearing is coupled, and the other side is provided with a through hole to which the end portion of the worm shaft is coupled. A stopper having a cutout portion formed by cutting an outer circumferential surface in a direction opposite to the worm wheel so that the inner circumferential surface of the large diameter portion communicates with the inner diameter; A block-shaped holder having a coupling hole formed at a central portion thereof so as to be coupled to an end of the worm shaft at an outer side of the stopper; A holder cap coupled to the inner end of the gear housing by inserting the holder and the stopper into a hollow shape in which one side is provided with a holder groove for press-fitting the holder to an inner surface thereof; And an elastic support coupled between the inner circumferential surface of the holder cap in the opposite direction of the worm wheel and the holder to support the holder having the worm shaft end coupled thereto in the worm wheel direction. Provide the reducer.

In addition, another embodiment of the present invention, the worm shaft bearing coupled to the opposite end of the motor shaft coupling portion of the worm shaft; Curved support portions facing each other supporting the worm wheel direction of the worm shaft bearing and the outer circumferential surface of the opposite direction of the worm wheel, respectively, and the first fixing part and the second fixing part which are bent in the radial direction opposite to each other at both ends of the support part. A plate spring formed of; And a clearance compensation groove spaced apart from the support of the plate spring at a predetermined distance by a hollow shape in which one side is blocked, and a first catching portion and a second catching portion to which the first fixing portion and the second fixing portion are press-fitted, respectively. It provides a reducer of the electric power assist steering device comprising a; a holder cap coupled to the inner end of the gear housing.

In addition, another embodiment of the present invention, the worm shaft bearing coupled to the opposite end of the motor shaft coupling portion of the worm shaft; To prevent the worm shaft bearing from being separated, one side is provided with a bearing coupling portion which is opened toward the motor shaft coupling portion and the outer ring of the worm shaft bearing is coupled, and the other side is provided with a bearing hole coupled with the end of the worm shaft bearing; ; A block-shaped holder having a coupling hole formed at a center thereof so as to be coupled to an end of the worm shaft from an outer side of the bearing cover; A holder cap coupled to an inner end of the gear housing in a hollow shape in which one side is provided with a holder groove to which the holder is coupled to an inner side thereof; A first elastic support coupled between the inner circumferential surface of the holder cap in the opposite direction of the worm wheel and the holder to support the holder having the worm shaft end coupled thereto in the worm wheel direction; And a second elastic support coupled between the inner circumferential surface of the holder cap in the worm wheel direction and the holder to support the holder coupled to the worm shaft end in the opposite direction to the worm wheel, but smaller than the elastic modulus of the first elastic support. It provides a reducer of the electric power auxiliary steering device, characterized in that it comprises a.

In addition, another embodiment of the present invention, the circumferential groove on the opposite end of the motor shaft coupling portion of the worm shaft and an elastic ring coupled to the groove; A bush whose inner circumferential surface compresses the elastic ring and is coupled to an end opposite to the motor shaft engaging portion of the worm shaft; A worm shaft bearing having an inner ring coupled to an outer circumferential surface of the bush to support an end opposite to the motor shaft engaging portion of the worm shaft; To prevent the worm shaft bearing from being separated, one side is provided with a bearing coupling portion which is opened toward the motor shaft coupling portion and the outer ring of the worm shaft bearing is coupled, and the other side is provided with a bearing hole coupled with the end of the worm shaft bearing; ; A block-shaped holder having a coupling hole formed at a center thereof so as to be coupled to an end of the worm shaft from an outer side of the bearing cover; A holder cap coupled to an inner end of a gear housing by inserting the holder and the bearing cover into a hollow shape in which one side is provided with a holder groove to which the holder is coupled to an inner surface thereof; And an elastic support coupled between the inner circumferential surface of the holder cap in the opposite direction of the worm wheel and the worm shaft end to support the worm shaft end in the worm wheel direction. .

According to embodiments of the present invention, in the speed reducer of the electric power assisted steering device, to prevent the play by the wear of the worm and the worm wheel, to reduce the rattle noise by the impact sound and backlash transmitted from the road surface, the play according to the change of the rotation torque By minimizing the amount of change, it is possible to accurately assist the driver's steering wheel operating force.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though 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 addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

3 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention, Figure 4 is a cross-sectional view showing a reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention. 5 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention.

3 to 5, the reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention, the worm shaft bearing 257 is coupled to the opposite end of the motor shaft engaging portion of the worm shaft 254; To prevent the worm shaft bearing 257 from being separated, one side is provided with a large diameter portion 351 to which the outer ring of the worm shaft bearing 257 is coupled to open to the motor shaft coupling portion, and the other side is an end portion of the worm shaft 254. Is provided with a through hole 353 is coupled, the large diameter portion 351 is formed with a cutout 355 is formed by cutting the outer circumferential surface in the opposite direction of the worm wheel 156 so that the inner circumferential surface of the large diameter portion 351 is in communication A stopper 350; A block-shaped holder 320 having a coupling hole 325 formed at a center thereof so as to be coupled to an end of the worm shaft 254 from the outside of the stopper 350; The holder 320 and the stopper 350 are inserted into a hollow shape in which one side is provided with a holder groove 315 to which the holder 320 is press-coupled to an inner side thereof and is coupled to an inner end of the gear housing 260. Holder cap 310; And a holder 320 coupled between the inner circumferential surface of the holder cap 310 in the opposite direction to the worm wheel 156 and the holder 320 to support the holder 320 coupled to the worm shaft 254 in the direction of the worm wheel 156. It is configured to include an elastic support (330).

The reduction gear assists the driver's steering force by rotating the steering shaft 106 while the worm 152 and the worm wheel 156 are interlocked by the driving force of the motor 146. The worm shaft bearing 257 is fastened to both ends of the worm shaft 254 interlocked with the shaft to support rotation of the worm shaft 254, and the worm wheel 156 and the worm 152 interlocked with the steering shaft 106 are gear housings ( 260).

On the other hand, in the opposite direction of the motor 146, a worm shaft bearing 257, in which a ball (see 258 in FIG. 2) is coupled between an inner ring (see 280 in FIG. 2) and an outer ring (see 270 in FIG. 2), has a gear housing ( 260 is supported at the end of the rotation of the worm shaft 254, the stopper 350 is inserted into the outer ring of the worm shaft bearing 257 and the damper 340 on the outer peripheral surface of the stopper 350 to the worm shaft bearing 257 Compressed and coupled, the outer side of the stopper 350, the holder 320 at the end of the worm shaft 254 is to compensate for the play while pushing the worm shaft 254 in the direction of the worm wheel 156 by the elastic support 330. .

The holder 320, the elastic support 330, the stopper 350, and the like are inserted into the holder cap 310 and coupled to the gear housing 260.

When the rotation durability of the worm shaft 254 progresses, noise and backlash are generated due to play caused by the wear of the worm 152 and the worm wheel 156, and the shock is transmitted from the road surface while driving the steering shaft 106. On the opposite side of the motor shaft coupling portion of the worm shaft 254 to reduce the backlash and impact sound, an elastic support 330, a damper 340, a stopper 350, etc., which pushes and supports the worm shaft 254 toward the worm wheel 156, are mounted. have.

The stopper 350 is formed of an engineering plastic and is coupled to an outer side of the worm shaft bearing 257 to prevent the worm shaft bearing 257 from being separated. One side of the stopper 350 is opened toward the motor shaft coupling portion, and the outer ring of the worm shaft bearing 257 is coupled. The large diameter portion 351 is provided, and the other side is provided with a through hole 353 to which the end of the worm shaft 254 is coupled.

In addition, the large diameter portion 351 of the stopper 350 is formed with a cutout portion 355 which cuts the outer peripheral surface in the opposite direction of the worm wheel 156 so that the inner circumferential surface of the large diameter portion 351 communicates with the damper 340 to be described later. The worm shaft bearing 257 can be compressed when the is coupled.

The holder 320 is formed in a block shape in which a coupling hole 325 is formed at the center of the holder 320 so as to be coupled to an end of the worm shaft 254 from the outside of the stopper 350, and the holder cap 310 has a holder 320 at an inner side thereof. One side of the holder groove 315 that is press-fitted is formed into a hollow shape, the holder 320 and the stopper 350 is inserted into the inside of the holder cap 310 is coupled to the inner end of the gear housing 260 do.

On the other hand, the elastic support 330 is coupled between the inner circumferential surface of the holder cap 310 in the opposite direction of the worm wheel 156 and the holder 320 so that the holder 320 coupled to the end of the worm shaft 254 in the worm wheel 156 direction. To compensate for the play caused by the wear of the worm 152 and the worm wheel 156, the elastic support 330 is a deformed coil spring that is formed in the slot or ellipse shape of the coil, unlike the general circular coil spring Can be formed.

Therefore, the load and the displacement are changed non-linearly, even if the same load is applied, the displacement is increased, and when the same load is applied, the displacement is larger than the general circular coil spring, so that the range of absorbing the load is widened.

In addition, a damper 340 is formed between the outer circumferential surface of the stopper 350 and the inner circumferential surface of the holder cap 310 in which a plurality of protrusions 343 are formed in the circumferential direction of the outer circumferential surface, wherein the protrusions 343 are holder caps 310. Compressively coupled to the stopper 350 and the worm shaft bearing 257 is in close contact.

Here, the damper 340 is provided with ribs 341 protruding to fill the cutout 355 on the inner circumferential surface of the worm wheel 156 in the opposite direction, so that the ribs 341 compress the outer ring of the worm shaft bearing 257. And combined.

In addition, the stopper 350 may be provided with a slit 357 that communicates the large diameter portion 351 and the through hole 353 by radially cutting the inner circumferential surface and the outer circumferential surface in the worm wheel 156 direction, and this slit 357. The stopper 350 is coupled to the damper 340 and the holder cap 310 by the elastic force that opens to both sides with respect to).

Accordingly, the stopper 350 reduces the impact noise and the rattle noise generated in the worm shaft 254 when the motor 146 is driven forward and backward.

The stopper 350 is formed of an engineering plastics material such as polyacetal (POM), polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), and the like. The noise generated from the worm shaft bearing 257 is prevented, and the stopper 350 has an O-ring 510 formed of an elastic material such as rubber or urethane on the outer circumferential surface of the stopper 350 instead of the damper as shown in FIG. 5. The worm shaft bearing 257 may be inserted and combined to be pressed.

6 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the second embodiment of the present invention, and FIG. 7 shows a part of the reducer of the electric power assisted steering apparatus according to the second embodiment of the present invention. Front view.

As shown in FIGS. 6 and 7, the speed reducer of the electric power assisted steering apparatus according to the second embodiment of the present invention includes a worm shaft bearing 257 coupled to an end opposite to the motor shaft coupling portion of the worm shaft 254; The worm wheel bearing 257 of the worm shaft bearing 257, the curved support portion 611 facing each other supporting the outer circumferential surface in the opposite direction of the worm wheel 156, and the opposite diameter at both ends of the support portion 611 A plate spring 610 formed of a first fixing part 613 and a second fixing part 615 which are bent and expanded in a direction; And a clearance compensation groove 313 spaced apart from the support portion 611 of the plate spring 610 by a predetermined distance on the inner side in a hollow shape in which one side is blocked, and the first fixing portion 613 and the second fixing portion 615. The first catching part 319 and the second catching part 317 which are respectively press-fitted are provided and a holder cap 310 coupled to the inner end of the gear housing 260;

The plate spring 610 is formed by bending a thin strip-shaped plate to be fixed to the inner surface of the holder cap 310 to support the worm shaft bearing 257, the worm wheel 156 direction of the worm shaft bearing 257 And curved support portions 611 opposed to each other supporting the outer circumferential surfaces of the worm wheel 156 in opposite directions, and bent and expanded in opposite radial directions at both ends of the support portions 611 to be coupled to the holder cap 310. The first fixing part 613 and the second fixing part 615 are provided to compensate for the clearance between the holder cap 310 and the worm shaft bearing 257.

In addition, the holder cap 310 has a clearance compensation groove 313 formed spaced apart from the support portion 611 of the plate spring 610 in which the worm shaft bearing 257 is inserted into the inner side in a hollow shape with one side blocked; A first catching portion 319 and a second catching portion 317 are provided to press-fix the first fixing portion 613 and the second fixing portion 615 of the plate spring 610, respectively. Is coupled to the inner end.

Therefore, if play is caused by wear of the worm 152 and the worm wheel 156, or when an impact transmitted from the road surface through the wheel and the steering shaft 106 occurs, the worm shaft 254 ends end in the direction of the worm wheel 156 and the worm wheel 156. When the plate spring 610 is supported by the first catching portion 319 and the second catching portion 317 when moving in the opposite direction, the gap between the holder cap 310 by the elastic force of the plate spring 610 The elastic movement within the 313 is absorbed.

8 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the third embodiment of the present invention, Figure 9 is a cross-sectional view showing a reducer of the electric power assisted steering apparatus according to the third embodiment of the present invention. to be.

8 and 9, the reducer of the electric power assisted steering apparatus according to an embodiment of the present invention, the worm shaft bearing 257 is coupled to the opposite end of the motor shaft engaging portion of the worm shaft 254; In order to prevent the worm shaft bearing 257 from being separated, one side of the worm shaft bearing 257 is opened toward the motor shaft coupling portion, and a bearing coupling portion 821 to which the outer ring of the worm shaft bearing 257 is coupled, and the other side of the worm shaft 254 A bearing cover 820 having a fastening hole 823 to which the end is coupled; A block-shaped holder 320 having a coupling hole 325 formed at a center thereof so as to be coupled to an end of the worm shaft 254 from the outside of the bearing cover 820; A holder cap 310 coupled to the inner end of the gear housing 260 in a hollow shape in which one side of the holder groove 315 is coupled to the inner surface of the holder groove 315; The holder is coupled between the inner circumferential surface of the holder cap 310 in the opposite direction of the worm wheel 156 and the holder 320 to support the holder 320 coupled to the end of the worm shaft 254 in the direction of the worm wheel 156. 1 elastic support 330; And the holder 320 coupled between the inner circumferential surface of the holder cap 310 in the worm wheel 156 direction and the holder 320 to support the holder 320 coupled to the end of the worm shaft 254 in the opposite direction to the worm wheel 156. And a second elastic support 810 formed smaller than the elastic modulus of the first elastic support 330.

The bearing cover 820 is a bearing to which the outer side of the worm shaft bearing 257 is coupled so that one side is opened toward the motor shaft coupling portion to prevent the worm shaft bearing 257 from being separated from the opposite end of the worm shaft 254. The coupling portion 821 is provided, and the other side is provided with a fastening hole 823 to which the end of the worm shaft 254 is coupled.

The holder 320 is formed in a block shape in which a coupling hole 325 is formed at a center thereof so as to be coupled to an end of the worm shaft 254 at an outer side of the bearing cover 820 coupled to the opposite end of the motor shaft coupling portion of the worm shaft 254. The first elastic support 330 is coupled to the opposite direction of the worm wheel 156, and the second elastic support 810 is coupled to the worm wheel 156.

The holder cap 310 has a hollow shape in which one side is blocked with a holder groove 315 to which the holder 320 is coupled to an inner side thereof, and a holder in which the first elastic support 330 and the second elastic support 810 are coupled. 320 is embedded and coupled to the inner end of the gear housing 260.

That is, the first elastic support 330 is coupled between the inner circumferential surface of the holder cap 310 in the opposite direction of the worm wheel 156 and the holder 320 so that the worm wheel 156 has a holder 320 coupled to an end of the worm shaft 254. The second elastic support 810 is coupled between the inner circumferential surface of the worm wheel 156 direction of the holder cap 310 and the holder 320 so that the end of the worm shaft 254 is coupled to the holder 320. ) Is supported in the opposite direction to the worm wheel 156.

Therefore, when play is caused by wear of the worm 152 and the worm wheel 156, or when an impact transmitted from the road surface through the wheel and the steering shaft 106 occurs, the worm shaft 254 ends are directed to the worm wheel 156 and the worm wheel ( When moving in the opposite direction of the 156, the first elastic support 330 and the second elastic support 810 is supported by the holder cap 310 while absorbing it by elastic movement by the elastic force.

Here, the second elastic support 810 is formed to be smaller than the elastic modulus of the first elastic support 330, so that the end of the worm shaft 254 is usually supported in the direction of the worm wheel 156, so that the clearance between the worm and the worm wheel 156 is reduced. It is intended to be reduced.

On the other hand, the first embodiment, the second embodiment and the third embodiment of the present invention, as shown in the fourth embodiment to be described later, the groove in the circumferential direction is formed at the end opposite to the motor shaft coupling portion of the worm shaft, this groove An elastic ring 920 (see FIGS. 10 and 11) is coupled thereto, and a bush 910 (see FIGS. 10 and 11) may be coupled to the elastic ring between the elastic ring and the worm shaft bearing 257.

10 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the fourth embodiment of the present invention, and FIG. 11 is a cross-sectional view showing the reducer of the electric power assisted steering apparatus according to the fourth embodiment of the present invention. .

As shown in Figs. 10 and 11, the reducer of the electric power assisted steering apparatus according to the fourth embodiment of the present invention forms a circumferential groove at an end opposite to the motor shaft engaging portion of the worm shaft 254, Coupled to the elastic ring 920; A bush 910 whose inner circumferential surface compresses the elastic ring 920 and is coupled to an end opposite to the motor shaft engaging portion of the worm shaft 254; A worm shaft bearing 257 having an inner ring coupled to the outside of the bush 910 to support an end opposite to the motor shaft engaging portion of the worm shaft 254; In order to prevent the worm shaft bearing 257 from being separated, one side of the worm shaft bearing 257 is opened toward the motor shaft coupling portion, and a bearing coupling portion 821 to which the outer ring of the worm shaft bearing 257 is coupled, and the other side of the worm shaft 254 A bearing cover 820 having a fastening hole 823 to which the end is coupled; A block-shaped holder 320 having a coupling hole 325 formed at a center thereof so as to be coupled to an end of the worm shaft 254 from the outside of the bearing cover 820; The holder 320 and the bearing cover 820 are inserted into a hollow shape in which one side is provided with a holder groove 315 to which the holder 320 is coupled to the inner side, and is coupled to the inner end of the gear housing 260. Holder cap 310; And an elastic support 330 coupled between the inner circumferential surface of the holder cap 310 in the opposite direction of the worm wheel 156 and the end of the worm shaft 254 to support the worm shaft 254 end in the worm wheel 156 direction. It is configured to include.

A circumferential groove is formed at an end of the worm shaft 254 opposite to the motor shaft coupling portion, and an elastic ring 920 is coupled to the groove, and a bush 910 is formed on the outer circumferential surface of the elastic ring 920. Are pressed together.

The worm shaft bearing 257 is coupled to the outer circumferential surface of the bush 910 to support an end opposite to the motor shaft coupling portion of the worm shaft 254.

The bearing cover 820 is provided with a bearing coupling portion 821, one side of which is opened toward the motor shaft coupling portion to prevent the worm shaft bearing 257 from being separated, and the outer ring of the worm shaft bearing 257 is coupled, and the other side of the worm shaft bearing 257. The end of the 254 is provided with a fastening hole 823 is coupled, the worm shaft 254 is coupled through and coupled to the outer ring of the worm shaft bearing 257.

The holder 320 has a block shape in which a coupling hole 325 is formed at a center thereof so as to be coupled to an end of the worm shaft 254, and is coupled to an outer side of the bearing cover 820.

The holder cap 310 has a hollow shape in which one side is blocked with a holder groove 315 into which the holder 320 is press-fitted on an inner side thereof, and the holder 320 and the bearing cover 820 are inserted into the holder housing 310. It is coupled to the inner end, the elastic support 330 is coupled between the inner circumferential surface of the holder cap 310 in the opposite direction of the worm wheel 156 and the end of the worm shaft 254 to support the end of the worm shaft 254 in the direction of the worm wheel 156 The play between the worm and the worm wheel 156 is reduced.

According to the embodiments of the present invention having such a shape and structure, in the reducer of the electric power assisted steering apparatus, it prevents the play by the wear of the worm and the worm wheel and reduces the rattle noise by the impact sound and backlash transmitted from the road surface, By minimizing the amount of play caused by the change of the rotation torque, it is possible to accurately assist the steering wheel operating force of the driver.

In the above description, all elements constituting the embodiments of the present invention are described as being combined or operating in combination, but the present invention is not necessarily limited to the embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be included, unless otherwise stated, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art unless otherwise defined, and unless expressly defined in the present invention It is not to be interpreted in an ideal or overly formal sense.

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. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of 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 protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a block diagram of a conventional electric power assisted steering device;

2 is a cross-sectional view showing a reducer of a conventional electric power assisted steering device;

3 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention;

4 is a cross-sectional view showing a reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention;

5 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention;

6 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the second embodiment of the present invention;

7 is a front view showing a part of the reducer of the electric power assisted steering apparatus according to the second embodiment of the present invention;

8 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the third embodiment of the present invention;

9 is a sectional view showing a reducer of the electric power assisted steering apparatus according to the third embodiment of the present invention;

10 is an exploded perspective view showing a part of the reducer of the electric power assisted steering apparatus according to the fourth embodiment of the present invention;

11 is a cross-sectional view showing a reducer of the electric power assisted steering apparatus according to the fourth embodiment of the present invention.

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

146: motor 152: worm

156: worm wheel 254: worm shaft

257: worm shaft bearing 310: holder cap

320: holder 330: elastic support

340: damper 350: stopper

510: O-ring 610: plate spring

810: second elastic support 820: bearing cover

910: bush 920: elastic ring

Claims (9)

A worm shaft bearing coupled to an end opposite to the motor shaft coupling portion of the worm shaft; In order to prevent the worm shaft bearing from being separated, one side is provided with a large diameter portion open to the motor shaft coupling portion to which the outer ring of the worm shaft bearing is coupled, and the other side is provided with a through hole to which the end portion of the worm shaft is coupled. A stopper having a cutout portion formed by cutting the outer circumferential surface in a direction opposite to the worm wheel so that the inner circumferential surface of the large diameter portion communicates with the inner circumferential surface; A block-shaped holder having a coupling hole formed at a center thereof so as to be coupled to an end of the worm shaft at an outer side of the stopper; A holder cap coupled to the inner end of the gear housing by inserting the holder and the stopper into a hollow shape in which one side is provided with a holder groove for press-fitting the holder to an inner surface thereof; And An elastic support coupled between the inner circumferential surface of the holder cap in the opposite direction of the worm wheel and the holder to support the holder having the worm shaft end coupled thereto in the worm wheel direction; Reducer of the electric power assisted steering device, characterized in that it comprises a. The method of claim 1, Reducer of the electric power assist steering device between the outer circumferential surface of the stopper and the inner circumferential surface of the holder cap is coupled to the damper formed with a plurality of projections in the circumferential direction of the outer circumferential surface, the projection is coupled to the holder cap. The method of claim 2, The damper is provided with a rib protruding to fill the incision to the inner circumferential surface in the opposite direction of the worm wheel, the rib is coupled to the outer ring of the worm shaft bearing is coupled to the power assist steering device. The method according to claim 2 or 3, The stopper is provided with a slit for cutting the inner circumferential surface and the outer circumferential surface of the worm wheel in the radial direction to communicate the large diameter portion and the through hole, and the damper and the holder cap are in close contact with each other based on the slit. Reducers for electric power assisted steering. The method of claim 1, O-ring is inserted into the outer peripheral surface of the stopper is coupled to the reducer of the electric power assist steering device, characterized in that the worm shaft bearing is coupled. A worm shaft bearing coupled to an end opposite to the motor shaft coupling portion of the worm shaft; To the worm wheel bearing of the worm shaft bearing, the support portion of the curved shape facing each other supporting the outer peripheral surface of the opposite direction of the worm wheel, and the first fixing part and the second fixing part which is bent in the radial direction opposite to each other at both ends of the support portion Plate springs formed; And It is provided with a clearance compensation groove spaced apart from the support of the plate spring by a certain distance on the inner side in a hollow shape with one side blocked, the first catching portion and the second catching portion to which the first fixing portion and the second fixing portion are press-fitted, respectively. A holder cap coupled to the inner end of the housing; Reducer of the electric power assisted steering apparatus, characterized in that it comprises a. A worm shaft bearing coupled to an end opposite to the motor shaft coupling portion of the worm shaft; A bearing cover on which one side is opened toward the motor shaft coupling part to prevent the worm shaft bearing from being separated, and a bearing coupling part is coupled to the outer ring of the worm shaft bearing, and the other side is provided with a fastening hole to which an end of the worm shaft is coupled; A block-shaped holder having a coupling hole formed at a center thereof so as to be coupled to an end of the worm shaft from an outer side of the bearing cover; A holder cap coupled to an inner end of the gear housing in a hollow shape in which one side is provided with a holder groove to which the holder is coupled to an inner side thereof; A first elastic support coupled between the inner circumferential surface of the holder cap in the opposite direction of the worm wheel and the holder to support the holder having the worm shaft end coupled thereto in the worm wheel direction; And A second elastic support coupled between the inner circumferential surface of the holder cap in the worm wheel direction and the holder to support the holder coupled to the worm shaft end in a direction opposite to the worm wheel, the second elastic support being smaller than the elastic modulus of the first elastic support; Reducer of the electric power assisted steering device, characterized in that it comprises a. The method according to any one of claims 1 to 6, wherein A circumferential groove is formed at an end opposite to the motor shaft coupling portion of the worm shaft, and an elastic ring is coupled to the groove, and a bush is pressed and coupled between the elastic ring and the worm shaft bearing. Reduction gears in power assisted steering. A worm shaft having a circumferential groove formed at an end opposite to the motor shaft coupling portion; An elastic ring coupled to the groove of the worm shaft; A bush whose inner circumferential surface compresses the elastic ring and is coupled to an end opposite to the motor shaft engaging portion of the worm shaft; A worm shaft bearing having an inner ring coupled to an outer circumferential surface of the bush to support an end opposite to the motor shaft engaging portion of the worm shaft; A bearing cover on which one side is opened toward the motor shaft coupling part to prevent the worm shaft bearing from being separated, and a bearing coupling part is coupled to the outer ring of the worm shaft bearing, and the other side is provided with a fastening hole to which an end of the worm shaft is coupled; A block-shaped holder having a coupling hole formed at a central portion thereof so as to be coupled to an end of the worm shaft from an outer side of the bearing cover; A holder cap coupled to an inner end of a gear housing by inserting the holder and the bearing cover into a hollow shape in which one side is provided with a holder groove to which the holder is coupled to an inner surface thereof; And An elastic support coupled between the inner circumferential surface of the holder cap in the opposite direction of the worm wheel and the worm shaft end to support the worm shaft end in the worm wheel direction; Reducer of the electric power assisted steering device, characterized in that it comprises a.

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