KR20110133668A - Reducer of electric power assisted steering and electric power assisted steering with same - Google Patents

Abstract

The present invention relates to a speed reducer of an electric power assisted steering device and an electric power assisted steering device having the same. According to the present invention, the play caused by the wear of the worm and the worm wheel is prevented and the occurrence of the rattle noise by the backlash is prevented. By minimizing the amount of play caused by the change in torque, it is possible to accurately assist the driver's steering wheel operating force.
In addition, there is an effect of preventing the premature wear of the gear due to the increase and decrease of the clearance of the worm shaft and the worm wheel, and the impact noise generated in the worm shaft when driving the motor in the forward and reverse directions.

Description

Reducer of electric power assisted steering device and electric power assisted steering device having same {Reducer of Electronic Power Steering Apparatus and Electronic Power Steering Apparatus having The Same}

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, 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, and an electric power assist steering device including the same.

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 reducer of the conventional electric power assisted steering device having such a structure has a problem in that premature wear of the gear and the operating force of the motor are increased by expansion due to moisture absorption of the worm wheel, and the worm and the worm wheel rotated by the driving of the motor are durable. While there was a problem that the rattle noise is generated due to the play and backlash caused by wear.

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.

The present invention has been made in the background, in the reduction gear of the electric power assist 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 play by the change of the rotation torque The objective is to accurately assist the steering wheel maneuverability of the driver by minimizing the amount of change.

In order to achieve the above object, an embodiment of the present invention includes a clearance compensation device that supports the worm shaft in a worm wheel direction and is coupled to a gear housing so as to compensate for the clearance between the worm shaft and the worm wheel, wherein the clearance compensation device includes: A bearing case having a worm shaft bearing combined with a worm shaft and having a protruding support portion at the other side thereof, and having a pivot shaft at a position spaced apart from the central shaft of the worm shaft; and a pivot movement of the bearing case in combination with the pivot shaft. And a pivot support member having an accommodation groove for receiving the support portion, and an elastic member coupled between the accommodation groove and the support portion to support the bearing case. Provide the reducer of the device.

In addition, another embodiment of the present invention, in the electric steering apparatus including a steering shaft connected to the steering wheel, and a reducer connected to the steering shaft to assist the steering force, the reducer to compensate for the play between the worm shaft and the worm wheel And a clearance compensation device supporting the worm shaft in a worm wheel direction and coupled to a gear housing, wherein the clearance compensation device includes a worm shaft bearing in which the worm shaft is coupled to one side thereof, and a support part protruding from the other side of the worm shaft. A pivot support member having a bearing case provided with a pivot shaft at a position spaced apart from a central axis, and a receiving groove accommodating the pivot shaft to support the pivot movement of the bearing case; And an elastic member coupled between the receiving groove and the support part to support the bearing case. It provides an electric power assisted steering device.

According to the present invention, it is possible to prevent the play caused by the wear of the worm and the worm wheel, to prevent the generation of rattle noise due to the backlash, and to accurately assist the steering wheel operating force of the driver by minimizing the amount of play caused by the change of the rotation torque. It is effective to be.

In addition, according to the present invention there is an effect to prevent the early wear of the gear due to the increase and decrease of the clearance of the worm shaft and the worm wheel, and the impact noise generated in the worm shaft when driving the motor in the forward and reverse directions.

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 and 4 are an exploded perspective view showing a play compensation device of the reducer of the electric power assisted steering apparatus according to an embodiment of the present invention,
5 to 9 is a schematic diagram showing an operating state of the play compensation device according to an embodiment of the present invention.

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 and 4 are exploded perspective views showing the clearance compensation device of the reducer of the electric power assisted steering apparatus according to an embodiment of the present invention, Figures 5 to 9 are views showing the operating state of the clearance compensation device according to an embodiment of the present invention. Schematic shown.

As shown in these drawings, the reducer of the electric power assisted steering apparatus according to the embodiment of the present invention, the worm shaft 254 in the direction of the worm wheel 156 to compensate for the gap between the worm shaft 254 and the worm wheel 156. It supports and has a clearance compensation device 300 is coupled to the gear housing (see 260 of Figure 2), the clearance compensation device 300, the worm shaft bearing 257 is coupled to the worm shaft 254 is inserted at one side And a support part 313 protruding from the other side, coupled with a bearing case 310 and a pivot shaft 315 provided with a pivot shaft 315 at a position spaced apart from the central shaft of the worm shaft 254. And a pivot support member 330 having an accommodation groove 333 for receiving the support portion 313 so as to support the pivot movement of the bearing case 310, and the accommodation groove 333 and the support portion 313. Is coupled between the elastic member 320 for supporting the bearing case 310 It is open configuration.

The reduction gear 300 of the electric power assisted steering apparatus according to the present invention has a structure in which the play compensation device 300 pivots the bearing case 310 so as to support the worm shaft 254 in the direction of the worm wheel 156 in the gear housing. Since the operating force is prevented from being increased due to the phenomena with the worm shaft 254 when the worm wheel 156 is inflated due to moisture absorption, there is no backlash due to the rotational durability of the worm 152 and the worm wheel 156. It is characteristic in that it loses and prevents 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 mounted on the gear housing. It is built in.

On the other hand, in the opposite direction of the motor 146, the worm shaft bearing 257 supports the rotation of the worm shaft 254 at the end of the gear housing, the bearing case 310 is inserted into the outer ring of the worm shaft bearing 257 and bearing The outer side of the case 310, the pivot support member 330, which is supported by the elastic member 320 is coupled to support the end of the worm shaft 254 coupled to the bearing case 310 in the direction of the worm wheel 156 to worm 152 And backlash generated in the worm wheel 156 is prevented.

The worm shaft bearing 257 is mounted between the bearing case 310 and the worm shaft 254 and supports the rotation of the worm shaft 254 at the end of the worm shaft 254, where the ball 258 rotates between the inner and outer rings of the bearing. And it reduces the rotational resistance of the worm shaft (254).

When the worm wheel 156, which is formed of a plastic material, is expanded due to moisture absorption, the play with the worm shaft 254 may be reduced by pinching the worm shaft 254, thereby pinching each other and requiring excessive operating force. Noise and backlash are generated due to the increase in play caused by wear of the 152 and the worm wheel 156. The worm shaft 254 is disposed on the opposite side of the motor coupling portion of the worm shaft 254 to compensate for the decrease and increase of the play. The clearance compensation device 300 is installed to remove the clearance by pushing toward).

The bearing case 310 is formed of an engineering plastic such as steel or acetal resin having rigidity, and a worm shaft bearing 257 having a worm shaft 254 coupled thereto is inserted at one side thereof, and a support 313 is protruded at the other side thereof.

In addition, the bearing case 310 is provided with a pivot shaft 315 at a position spaced apart from the central shaft of the worm shaft 254, so that the worm wheel 156 is absorbed to expand the volume or volume due to wear with the worm shaft 254. Is reduced, the bearing case 310 is configured to be rotatable about the pivot shaft 315.

The pivot shaft 315 is integrally formed in the bearing case 310 as shown in FIG. 3, or the pivot shaft 315 is separately manufactured as shown in FIG. 4 to the shaft hole 415 formed in the bearing case 310. It may be press fit.

The pivot support member 330 coupled to the outer side of the bearing case 310 is fixedly coupled to the gear housing, and the shaft coupling hole 335 is formed at a position corresponding to the pivot shaft 315 so that the bearing case 310 Is coupled to the pivot shaft 315 of the bearing case 310 has a receiving groove 333 is inserted and accommodated to support the pivot rotational movement of the bearing case (310).

The receiving groove 333 is formed in an arc shape centering on the pivot shaft 315 to enable the pivoting movement of the bearing case 310.

In addition, one side of the circumferential direction of the receiving groove 333 may be provided with an adjustment hole 420 penetrating the outer peripheral surface of the pivot support member 330 as shown in Figure 4, the adjustment hole 420, the elastic member Adjusting the amount of compression of the 320, the elastic member 320 is coupled to the adjustment member 430 for adjusting the elastic force supporting the bearing case 310.

The adjusting hole 420 is formed at right angles to one circumferential side surface of the receiving groove 333 formed in an arc shape so that the adjusting member 430 is supported and the elastic member 320 can be fastened. The threaded part is machined so that the screw is screwed together.

In addition, a portion of the outer circumferential surface of the pivot support member 330 communicates with the adjustment hole 420 and is provided with a flat portion 425 perpendicular to the fastening direction of the adjustment member 430, that is, the center axis direction of the adjustment hole 420. Since the adjustment member 430 is coupled to the adjustment hole 420, the overall volume and weight of the pivot support member 330 are not increased and the gear housing does not protrude outward from the outer circumferential surface of the pivot support member 330. Or interference with other components.

The adjustment member 430 is provided with a small diameter portion inserted into the adjustment hole 420 and a large diameter portion supported and fixed to the flat portion 425 and press-fitted or screwed into the adjustment hole 420, and screwed to enable fine adjustment. It's good to be.

When the elastic member 320 is compressed by a predetermined amount by the adjustment member 430, the bearing case 310 is pivoted about the pivot shaft 315 by the elastic force of the elastic member 320. In addition, the worm 152 and the worm wheel 156 can be applied in the opposite direction as well as the coupling direction, the worm shaft 254 viewed in a direction parallel to the worm shaft 254, worm wheel 156, play gap compensation The combined state of the device 300 is shown in FIGS. 5 and 7.

That is, FIGS. 5 and 7 show a state in which the worm wheel 156 is viewed from one of the directions parallel to the worm shaft 254 and the opposite direction, respectively, in which the worm wheel 156 is not expanded by moisture absorption or reduced by wear. When the worm wheel 156 expands in the radial direction due to the moisture absorption of the worm wheel 156 as shown in 6 (a), the bearing case 310 has the worm wheel 156 based on the center 315a of the pivot shaft 315. The pivot rotational motion is performed by a predetermined angle "d" in a direction away from the direction (clockwise in the drawing). Here, the angle "d" represents the angle of movement between the center 254a of the initial worm axis about the pivot axis 315 and the center 254b of the worm axis moved by the hygroscopic expansion of the worm wheel 156.

When the bearing case 310 pivots in a direction away from the worm wheel 156 (clockwise in the drawing) with respect to the center 315a of the pivot shaft 315, the support part (a) of FIG. 313 compresses the elastic member 320 to absorb the change in play due to the hygroscopic expansion of the worm wheel 156.

On the contrary, when the moisture absorption amount of the worm wheel 156 is reduced, when the worm wheel 156 is reduced and returned to its original position as shown in FIG. 6B, the elastic member 320 is supported as shown in FIG. 313 is elastically restored while pushing in a direction approaching the worm wheel 156 (counterclockwise in the drawing) to maintain the play.

In addition, the adjustment member 430 is inserted into one circumferential side of the receiving groove 333 so as to more easily support the elastic member 320 when the elastic member 320 is supported between the elastic member 320 and the adjustment member 430. The support plate 810 may be coupled.

On the other hand, when the worm wheel 156 is worn due to durability and the radial size of the worm wheel 156 is reduced to increase the clearance with the worm shaft 254, the elastic member 320 that was compressed during initial assembly as shown in FIG. Is elastically restored while the support portion 313 of the bearing case 310 is pushed in a direction (counterclockwise in the drawing) close to the worm wheel 156 to maintain the play. That is, the bearing case 310 makes a pivotal rotation movement by a predetermined angle "g" in a direction (counterclockwise direction) in which the bearing case 310 approaches the worm wheel 156 based on the center 315a of the pivot shaft 315. .

Here, the angle "g" represents the angle of movement between the center 254a of the initial worm shaft and the center 254b of the worm shaft moved due to the wear of the worm wheel 156 with the pivot axis 315 as the center 315a.

Therefore, the worm shaft 254 is increased by premature wear and operating force of the gear generated by simply pushing the worm shaft 254 only in the coupling direction of the worm 152 and the worm wheel 156, and the worm shaft 254 when driving the motor 146 in the forward and reverse directions. It is possible to prevent the impact noise and rattle noise generated in the), and in any case it is possible to compensate for the play of the worm shaft and the worm wheel 156.

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.

In addition, there is an effect of preventing the premature wear of the gear due to the increase and decrease of the clearance of the worm shaft and the worm wheel, and the impact noise generated in the worm shaft when driving the motor in the forward and reverse directions.

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. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or excessively formal sense unless explicitly defined in the present invention.

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 not intended to limit the technical idea of the present invention but to describe 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.

254: worm shaft 257: worm shaft bearing
300: play compensation device 310: bearing case
313: support portion 315: pivot axis
320: elastic member 330: pivot support member
333: receiving groove 335: shaft coupling hole
420: adjusting hole 430: adjusting member

Claims (16)

In order to compensate for the clearance of the worm shaft and the worm wheel is provided with a clearance compensation device for supporting the worm shaft in the worm wheel direction and coupled to the gear housing,
The gap compensation device,
A bearing case having a worm shaft bearing in which the worm shaft is coupled to one side thereof and having a supporting part protruding from the other side thereof, the pivot case being provided at a position spaced apart from the central axis of the worm shaft;
A pivot support member coupled with the pivot shaft and having an accommodation groove for receiving the support to support pivot movement of the bearing case; And
An elastic member coupled between the accommodation groove and the support to support the bearing case;
Reducer of the electric power assisted steering device, characterized in that it comprises a. The method of claim 1,
Reduction groove of the electric power assist steering device characterized in that the receiving groove of the pivot support member is formed in an arc shape around the pivot axis. The method of claim 2,
The pivot support member is provided with an adjustment hole penetrating the outer circumferential surface on one side of the circumferential direction of the receiving groove, and the adjustment hole for adjusting the compression amount of the elastic member is coupled to the electric power assist steering. Reducer of the device. The method of claim 3, wherein
The control member is a reducer of the electric power assist steering device, characterized in that screwed to the adjustment hole. The method of claim 3, wherein
And the pivot support member communicates with the adjustment hole and has a flat portion corresponding to the fastening direction of the adjustment member. The method of claim 5, wherein
The adjusting member is a reducer of the electric power assist steering device characterized in that the small diameter portion is inserted into the adjustment hole and the large diameter portion is supported and fixed to the flat portion. The method of claim 1,
The pivot shaft is a reducer of the electric power assisted steering apparatus, characterized in that formed integrally with the bearing case. The method of claim 1,
The bearing case has a shaft hole is formed in a position spaced apart from the central axis of the worm shaft, the reduction shaft of the electric power assisted steering apparatus, characterized in that the pivot shaft is press-fitted to the shaft hole. In the electric steering apparatus including a steering shaft connected to the steering wheel, and a reducer connected to the steering shaft to assist the steering force,
The reducer is provided with a clearance compensation device for supporting the worm shaft in the worm wheel direction and coupled to the gear housing to compensate for the gap between the worm shaft and the worm wheel,
The gap compensation device,
A bearing case having a worm shaft bearing in which the worm shaft is coupled to one side thereof and having a supporting part protruding from the other side thereof, the pivot case being provided at a position spaced apart from the central axis of the worm shaft;
A pivot support member coupled with the pivot shaft and having an accommodation groove for receiving the support to support pivot movement of the bearing case; And
An elastic member coupled between the accommodation groove and the support to support the bearing case;
Electric power assisted steering, characterized in that it comprises a. The method of claim 9,
Receiving groove of the pivot support member is an electric power assisted steering device, characterized in that formed in an arc shape around the pivot axis. The method of claim 10,
The pivot support member is provided with an adjustment hole penetrating the outer circumferential surface on one circumferential side of the receiving groove, and the adjustment hole for adjusting the compression amount of the elastic member is coupled to the electric power assist steering. Device. The method of claim 11,
And the adjustment member is screwed to the adjustment hole. The method of claim 11,
And the pivot support member communicates with the adjustment hole and has a flat portion corresponding to the fastening direction of the adjustment member. The method of claim 13,
And the adjustment member includes a small diameter portion inserted into the adjustment hole and a large diameter portion supported and fixed to the flat portion. The method of claim 9,
And the pivot shaft is integrally formed with the bearing case. The method of claim 9,
The bearing case has a shaft hole is formed in a position spaced apart from the central axis of the worm shaft, the pivotal power assisted steering device, characterized in that the pivot shaft is press-fitted to the shaft hole.

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