KR101251241B1 - Reducer of Electronic Power Steering Apparatus - Google Patents

Abstract

The present invention relates to a speed reducer of an electric power assisted steering apparatus.

The present invention is a worm shaft bearing for supporting the opposite end of the motor shaft coupling portion of the worm shaft is formed with a worm to be engaged with the worm wheel, and a hollow bearing bush coupled while maintaining a constant clearance while surrounding the outer ring of the worm shaft bearing, and the center A block-shaped guide holder coupled to the outside of the bearing bush, a first elastic support for supporting the guide holder in the worm wheel direction, and an outer circumference of the bearing bush; And a holder housing coupled to an inner end of the gear housing and having a holder groove into which the guide holder is inserted, and a support groove into which the elastic support is coupled. Provide the reducer.

According to the present invention, in the speed reducer of the electric power assisted steering device, it prevents the play caused by the wear of the worm and the worm wheel, prevents the generation of rattle noise by the backlash, and minimizes the amount of play change caused by the change of rotation torque, the driver's steering There is an effect that can accurately assist the wheel operating force.

Steering, Reducer, Plug Bolt, Plug Nut, Motor

Description

Reducer of Electronic Power Steering Apparatus

The present invention relates to a speed reducer of an electric power assisted steering apparatus. 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, prevents the occurrence of the rattle noise by the backlash, and minimizes the amount of play change 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 wheel operation 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.

The steering system 130 includes a steering shaft 106 having one side connected to the steering wheel 102 and rotating with the steering wheel 102 and the other side connected to the pinion shaft 108 via a pair of universal joints 104 ). 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 includes a torque sensor 142 that senses a torque applied by the driver to the steering wheel 102 and outputs an electric signal proportional to the sensed torque and a torque sensor 142 that outputs an electric signal proportional to the sensed torque based on an electric signal transmitted from the torque sensor 142 An electronic control unit 144 for generating a control signal and a motor 146 for generating an auxiliary power based on the control signal transmitted from the electronic control unit 144 and an auxiliary power generated by the motor 146 to the steering shaft 106, And a speed reducer 150 having a worm 152 and a worm wheel 156 to transmit the worm 152 and the worm wheel 156 to each other.

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 is connected to the motor 146 via a damping coupler 240 so that the worm shaft 254 is rotated by driving of the motor 146.

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 is provided with a motor 146 for providing a driving force to the worm shaft 254 at one side of the gear housing 260 and a worm 152 and a worm wheel 156. The gear housing 260 includes a gear housing 260, The motor 146 is coupled to the bolt 250 by a 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 assist steering apparatus having the above structure controls the driving of the motor by the electronic control unit provided in the vehicle according to the driving condition of the vehicle, and the rotation of the worm shaft by the driving of the motor is controlled by the steering wheel And is transmitted to the steering shaft in addition to the rotational force, so that the steering operation state of the driver can be maintained smoothly and stably.

However, the reducer of the conventional electric power assisted steering device has a problem in that the worm and the worm wheel rotated by the driving of the motor cause the rattle noise due to play and backlash caused by wear when the worm and the worm wheel are durable.

In addition, this has a problem in that it is not possible to accurately provide a steering assistance force to assist the steering wheel operation force of the driver.

In order to solve the above problems, the present invention, in the reducer of the electric power assisted steering device, to prevent the play by the wear of the worm and the worm wheel and to prevent the generation of rattle noise by the backlash, the amount of play change according to the change of the rotation torque The purpose of the present invention is to provide a speed reducer of an electric power assisted steering apparatus that can accurately assist the driver's steering wheel operating force.

In order to achieve the above object, the present invention provides a worm shaft bearing for supporting the opposite end of the motor shaft coupling portion of the worm shaft in which a worm meshed with a worm wheel is formed, and a hollow shape that is coupled while maintaining a constant clearance while surrounding the outer ring of the worm shaft bearing. A bearing bush having a bearing bush, a shaft guide hole through which an end of the worm shaft penetrates, and a block-shaped guide holder coupled to an outer side of the bearing bush, a first elastic support supporting the guide holder in the worm wheel direction, and the It is characterized in that it comprises a holder housing coupled to the inner end of the gear housing while surrounding the outer periphery of the bearing bush and a holder groove into which the guide holder is inserted, and a support groove to which the elastic support is coupled. Provides a reducer for an electric power assisted steering system.

According to the present invention, in the speed reducer of the electric power assisted steering device, it prevents the play caused by the wear of the worm and the worm wheel, prevents the generation of rattle noise by the backlash, and minimizes the amount of play change caused by the change of rotation torque, the driver's steering There is an effect that can accurately assist the wheel operating force.

Hereinafter, some embodiments of the present invention 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 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 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."

3a and 3b are a perspective view and a cross-sectional view showing a part of the speed reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention, Figure 4a and 4b is a view of the electric power assisted steering apparatus according to the second embodiment of the present invention It is a perspective view and sectional drawing which shows a part of reducer.

As shown in FIGS. 3A and 3B, the reduction gear 300 of the electric power assisted steering apparatus according to the first embodiment of the present invention includes a worm shaft 254 having a worm 152 meshed with a worm wheel 156. A worm shaft bearing 257 for supporting the opposite end of the motor shaft coupling portion of the worm shaft, a hollow bearing bush 310 coupled to the outer ring 270 of the worm shaft bearing 257 while maintaining a constant clearance therebetween; A block-shaped guide holder 320 having an axial hole 325 through which an end of the worm shaft 254 penetrates is coupled to an outer side of the bearing bush 310, and the guide holder 320 is connected to the worm wheel 156. A holder groove 333 coupled to an inner end of the gear housing 260 and surrounding the outer circumference of the bearing bush 310 to support the first elastic support 340 supporting the direction, and into which the guide holder 320 is inserted. ) And a support groove 335 to which the first elastic support 340 is coupled. It is configured to include a holder housing 330.

In addition, the holder housing 330 may be further coupled to the second elastic support member 350 coupled to the support groove 335 to support the first elastic support member 340 toward the guide holder 320.

Here, the second elastic support 350 is formed of a material having a spring constant greater than that of the first elastic support 340, and the compensation of the play due to residual vibration or wear caused by the rotation of the worm shaft 254 may be determined by the first elastic support 340. The second elastic support member 350 absorbs the large vibration generated by the vehicle traveling off-road and the impact caused by the reverse input.

In the second embodiment of the present invention, as illustrated in FIGS. 4A and 4B, a bush having a Teflon coating between the guide holder 320 and the end of the worm shaft 254 to reduce rotational friction with the worm shaft 254 ( Not shown) or the bearing 360 is inserted and coupled, except for the bush or the bearing is the same as the first embodiment of the present invention will be described below with reference to the first embodiment of the present invention shown in Figures 3a and 3b Let's do it.

In the reducer 300 of the electric power assisted steering apparatus according to the present invention, the first elastic support 340 or the second elastic support 350 moves the worm shaft 254 in the direction of the worm wheel 156 in the gear housing 260. It has a structure to support, the backlash and noise is eliminated during the rotation durability of the worm 152 and the worm wheel 156, it is characterized by preventing the rattle noise.

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, the worm shaft bearing 257 in which the ball 258 is coupled between the inner ring 280 and the outer ring 270 is rotated at the end of the gear housing 260. The bearing bush 310 is inserted into the outer ring 270 of the worm shaft bearing 257, and the holder housing 330 couples the bearing bush 310 to the outside of the bearing bush 310, and the gear housing 260. In the inner side of the holder housing 330, the first elastic support 340 supports the end of the worm shaft 254 in the direction of the worm wheel 156 via the guide holder 320 to the worm 152 and the worm wheel. It is to prevent the backlash and the noise caused by the wear and the like of (156).

The worm shaft bearing 257 is mounted at the end of the worm shaft 254 and supports rotation of the worm shaft 254 at both ends of the worm shaft 254, wherein a ball 258 is disposed between the inner ring 280 and the outer ring 270 of the bearing. Rotates and reduces the rotational resistance of the worm shaft 254.

When the rotational durability of the worm shaft 254 progresses, noise and backlash are generated due to the play caused by the wear of the worm 152 and the worm wheel 156. The opposite side of the motor shaft coupling portion of the worm shaft 254 may compensate for such play. The first elastic support 340 is attached to the worm shaft 254 to remove the play by pushing the worm shaft 254 toward the worm wheel 156.

The bearing bush 310 is coupled to surround the outer ring 270 of the worm shaft bearing 257 in a hollow shape, the end portion of the worm shaft 254 is penetrated to the center portion is coupled to the worm shaft bearing 257 and the outer ring of the worm shaft bearing 257 270 is press-fitted while wrapping to prevent the worm shaft bearing 257 from being separated while having a predetermined clearance with the worm shaft bearing 257.

In addition, the bearing bush 310 may be formed of a material such as rubber or urethane, to prevent the impact noise generated in the worm shaft 254 during the forward and reverse driving of the motor 146.

The holder housing 330 is coupled to the inner end of the gear housing 260 while surrounding the outer circumference of the bearing bush 310 to support the worm shaft 254.

That is, the holder housing 330 is coupled to the inner end of the gear housing 260 while surrounding the outer circumference of the bearing bush 310 and the holder groove 333 into which the guide holder 320 to be described later is inserted, and the first A support groove 335 to which the elastic support 340 is coupled is formed, so that the first elastic support 340 is supported by the holder housing 330 to support the guide holder 320 coupled to the worm shaft toward the worm wheel 156. Done.

The guide holder 320 is coupled to the worm shaft 254 on the outside of the bearing bush 310, and is formed in a block shape with a shaft hole 325 through which an end of the worm shaft 254 penetrates. The holder groove 333 and the play 370 of the holder housing 330 are formed and coupled to the end of the worm shaft 254.

Here, the guide holder 320 may be Teflon coating to reduce the rotational friction resistance with the worm shaft 254 end.

Accordingly, when the first elastic support 340 supports the guide holder 320 having the worm shaft 254 coupled thereto with elastic force toward the worm wheel 156, the guide holder 320 may play with the holder housing 330. It is supported within the range to the worm wheel 156 to compensate for the clearance to eliminate noise and backlash.

On the other hand, the worm shaft 254 is to compensate for the play with the worm wheel 156 by the first elastic support 340 in the holder housing 330, where the first elastic support 340 is the holder housing 330 It is coupled to the support groove 335 formed in the opposite direction of the worm wheel 156 of the to support the end of the worm shaft 254 toward the worm wheel 156 to compensate for the play with the worm wheel 156.

Here, the first elastic support 340 has a support portion 345 in close contact with the outer circumferential surface of the guide holder 320, and both ends 343 bent at both sides from the support portion 345 are holder housings 330. It is formed of a leaf spring coupled to the support groove 335 of the).

On the other hand, the holder housing 330 is coupled to the support groove 335 may be coupled to the second elastic support 350 for supporting the first elastic support 340 toward the guide holder 320, where the second elastic support The 350 may be formed of a leaf spring whose center is in close contact with the support 345 of the first elastic support 340 and bent so that its end is coupled to the support groove 335 of the holder housing 330.

However, the present invention is not limited thereto, and in some cases, the first elastic support 340 and the second elastic support 350 are coupled to the inside of the holder housing 330 to support the guide holder 320 toward the worm wheel 156. As far as possible, any shape of elastomer, including coil springs, would be possible.

According to the present invention having such a shape and structure, in the reduction gear of the electric power assist steering device, it prevents the play caused by the wear of the worm and the worm wheel, and prevents the generation of rattle noise by the backlash, the amount of play change according to the change of the rotation torque By minimizing this, it is possible to accurately assist the driver's steering wheel operating force.

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. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more.

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.

The description above 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 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;

3A and 3B are a perspective view and a sectional view showing a part of a reducer of the electric power assisted steering apparatus according to the first embodiment of the present invention;

4A and 4B are a perspective view and a cross-sectional view showing a part of a reducer of the electric power assisted steering apparatus according to the second 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 258: ball

270: outer ring 310: bearing bush

320: guide holder 325: shaft hole

330: holder housing 333: holder groove

335: support groove 340: first elastic support

350: second elastic support 360: bearing

Claims (8)

A worm shaft bearing supporting an opposite end of the motor shaft engaging portion of the worm shaft on which a worm engaged with the worm wheel is formed; A hollow bearing bush coupled to the outer ring of the worm shaft bearing while maintaining a constant clearance therebetween; A block-shaped guide holder having a shaft hole through which an end of the worm shaft penetrates in a central portion thereof and coupled to an outer side of the bearing bush; A first elastic support for supporting the guide holder in the worm wheel direction; And A holder housing coupled to an inner end of the gear housing while surrounding the outer circumference of the bearing bush and having a holder groove into which the guide holder is inserted and a support groove into which the elastic support is coupled; Reducer of the electric power assisted steering apparatus, characterized in that it comprises a. The method of claim 1, The first elastic support, the support portion in close contact with the outer peripheral surface of the guide holder is formed in the center, both ends bent from the support portion is an electric power characterized in that the leaf spring is coupled to the support groove of the holder housing Reduction gear for auxiliary steering. The method of claim 1, The guide holder is a reducer of the electric power assist steering device, characterized in that the Teflon coating. The method of claim 1, The holder groove of the holder housing is a reducer of the electric power assist steering device, characterized in that a constant clearance is formed toward the guide holder and the worm wheel. The method of claim 1, The reducer of the electric power assisted steering device, characterized in that the bush is inserted and coupled between the guide holder and the end of the worm shaft Teflon coating. The method of claim 1, Reducer of the electric power assist steering device characterized in that the bearing is inserted between the guide holder and the end of the worm shaft. The method of claim 1, The holder housing is coupled to the support groove, the reducer of the electric power assist steering device, characterized in that the second elastic support for supporting the first elastic support toward the guide holder is coupled. The method of claim 7, wherein The second elastic support, the reducer of the electric power assist steering device, characterized in that the center is in close contact with the support of the first elastic support and bent so that the end is coupled to the support groove of the holder housing.

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