KR20110073004A - Reducer of electronic power steering apparatus and electronic power steering apparatus using the same - Google Patents

Abstract

PURPOSE: A reducer of electric-powered power auxiliary steering system and electric-powered power auxiliary steering system using the same are provided to improve the steering feeling of a driver by reducing the rotation resistance of a worm shaft and worm shaft bearing. CONSTITUTION: A reducer of electric-powered power auxiliary steering system comprises worm shaft bearings(257a,257b), a gear housing(260), and a housing damper(310a). The worm shaft bearing is combined with both end part of a worm shaft(254). The worm shaft bearing supports the rotation of the worm shaft. The gear housing accepts a gear system part including the worm shaft, a worm shaft bearing, and a worm wheel(156). The housing damper is combined in the inner wall of the gear housing and worm shaft bearing. The housing damper elastically supports the outer-race of the worm shaft bearing in an axial direction.

Description

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

The present invention relates to a speed reducer of an electric power assisted steering device. More specifically, it reduces rattle noise caused by an increase in backlash due to friction and wear of the worm and worm wheels, or an impact transmitted from the road surface through the wheel and the steering shaft, and reduces the grip and rotation resistance of the worm shaft and the worm shaft bearing. The present invention relates to a speed reducer of an electric power assist steering device and to an electric power assist steering device using 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 wheel 102 disposed in a driver's seat and a steering shaft 106 connected thereto, and A steering column 130 for fixing the steering shaft to the vehicle body, a rack pinion mechanism unit 110 including a rack gear and a pinion gear for converting rotational force input from the steering shaft 106 into linear motion, and tie rods at both ends thereof. And a rack bar 112 having a knuckle arm 124.

The steering column 130 has a steering shaft 106 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 joints 104. . In addition, the pinion shaft 108 is connected to the rack bar 112 through the rack pinion mechanism unit 110, both ends of the rack bar 112 through the tie rods 122 and the knuckle arm 124 of the vehicle wheel 126 Is connected to.

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 is generated 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 has a worm shaft 254 having a worm 152 formed thereon, and worm shaft bearings 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 worm shaft bearing in order to prevent the worm shaft bearing 257 is spaced in the axial direction of the worm shaft 254 257, 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 steering wheel (102 in FIG. And a rotational force of the worm shaft 254 driven by the driving of the motor 146 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 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 reduction gear of the conventional electric power assist steering device has a problem in that manufacturing errors and assembly errors accumulate on the coupling portion of the worm shaft and the motor shaft, causing a bearing jam and increasing rotational resistance of the worm shaft, and also a worm and a worm wheel. When this durability progresses, play occurs due to abrasion, rattle noise occurs due to backlash, and shock caused by the rattle noise caused by the impact transmitted through the wheels and the steering shaft from the road surface to cause discomfort to the driver when operating the steering wheel. There was this.

Accordingly, the present invention has been made to solve the above-described problems, reducing the rattle noise caused by the increase in backlash due to friction and wear of the worm and the worm wheel, or the impact transmitted through the wheel and the steering shaft from the road surface, The purpose is to increase the steering feeling of the driver by reducing the grip and rotational resistance of the worm shaft and worm shaft bearings.

In order to achieve the above object, an embodiment of the present invention includes: a worm shaft bearing coupled to both ends of the worm shaft to support rotation of the worm shaft so as to absorb vibration and noise generated by friction and wear during operation of the worm shaft and the worm wheel; A gear housing accommodating the gear mechanism including the worm shaft, the worm shaft bearing, and the worm wheel; And a housing damper coupled between the worm shaft bearing coupled to the opposite end of the worm shaft bearing of the worm shaft bearing and the inner wall of the gear housing to support the outer ring of the worm shaft bearing with an axial elastic force. It provides a reducer of the electric power assist steering device, characterized in that.

In addition, an embodiment of the present invention, a worm shaft bearing coupled to both ends of the worm shaft to support the rotation of the worm shaft so as to absorb vibration and noise generated by friction and wear during operation of the worm shaft and the worm wheel; A gear housing accommodating the gear mechanism including the worm shaft, the worm shaft bearing, and the worm wheel; And a plug damper coupled between a worm shaft bearing coupled to an end portion of the worm shaft bearing of the worm shaft bearing and a plug bolt coupled to the worm shaft to support the outer ring of the worm shaft bearing with an axial elastic force. It provides a reducer of the electric power assisted steering, characterized in that configured.

In addition, an embodiment of the present invention, in the electric power assist steering device for assisting the steering force of the steering wheel via the reducer and the motor, the reducer, vibration and noise generated by friction and wear during operation of the worm shaft and the worm wheel A worm shaft bearing coupled to both ends of the worm shaft to absorb the worm shaft, thereby supporting rotation of the worm shaft; A gear housing accommodating the gear mechanism including the worm shaft, the worm shaft bearing, and the worm wheel; And a housing damper coupled between the worm shaft bearing coupled to the opposite end of the worm shaft bearing of the worm shaft bearing and the inner wall of the gear housing to support the outer ring of the worm shaft bearing with an axial elastic force. An electric power assisted steering device is provided.

According to the present invention, the rattle noise caused by the increase in backlash due to the friction and wear of the worm and the worm wheel, or the impact transmitted through the wheel and the steering shaft from the road surface is also reduced, and the grip and rotational resistance of the worm shaft and the worm shaft bearing are reduced. This reduces the driver's steering feel.

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 addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

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".

3A, 3B, and 3C are cross-sectional views showing a reducer of the electric power assisted steering apparatus according to the first, second, and third embodiments, respectively, and FIG. 4 is a third embodiment of the present invention. 5 is an exploded perspective view illustrating a speed reducer of the electric power assisted steering apparatus according to the embodiment, and FIG. 5 is a graph comparing noise generated in the speed reducer and the conventional speed reducer of the electric power assisted steering apparatus according to the embodiments of the present invention.

The reducer 300a of the electric power assisted steering apparatus according to the first embodiment of the present invention absorbs vibration and noise generated by friction and wear when the worm shaft 254 and the worm wheel 156 operate. The worm shaft 254 Worm shaft bearings (257a, 257b) coupled to both ends of the support for supporting the rotation of the worm shaft (254); A gear housing 260 accommodating a gear mechanism including the worm shaft 254, the worm shaft bearings 257a and 257b, and the worm wheel 156; And a worm shaft bearing 257a coupled between the worm shaft bearing 257a coupled to an opposite end of the worm shaft bearings 257a and 257b of the worm shaft 254, and the inner wall of the gear housing 260. And a housing damper 310a for supporting the outer ring of 257a with an axial elastic force.

On the other hand, the reduction gear 300b of the electric power assisted steering apparatus according to the second embodiment of the present invention, to absorb the vibration and noise generated by friction and wear when the worm shaft 254 and the worm wheel 156, the worm shaft Worm shaft bearings 257a and 257b coupled to both ends of 254 to support rotation of the worm shaft 254; A gear housing 260 accommodating a gear mechanism including the worm shaft 254, the worm shaft bearings 257a and 257b, and the worm wheel 156; And a worm shaft bearing 257b coupled to an end portion of the worm shaft 254 connected to the motor shaft 320 of the worm shaft 254, and a plug bolt 210 coupled to the worm shaft 254. And a plug damper 310b for supporting the outer ring of the worm shaft bearing 257b with an elastic force in the axial direction.

In addition, the reduction gear 300c according to the third embodiment is coupled to the end portion of the motor shaft 320 of the third worm shaft 254 of the worm shaft bearings 257a and 257b in addition to the reduction gear 300 according to the first embodiment. A plug damper 310b is coupled between the worm shaft bearing 257b and the plug bolt 210 coupled to the worm shaft 254 to support the outer ring of the worm shaft bearing 257b with an axial elastic force. It is composed.

The worm shaft bearings 257a and 257b coupled to the end portions of the worm shaft 254 and the opposite ends thereof coupled to the motor shaft 320 have balls engaged between the inner and outer rings to support rotation of the worm shaft 254. .

The reduction gears 300a, 300b, and 300c rotate the steering shaft 106 while the worm 152 and the worm wheel 156 are interlocked by the driving force of the motor 146 to assist the driver's steering force. Worm shaft bearings 257a and 257b are fastened to both ends of the worm shaft 254 interlocked with the motor shaft 320 to drive rotation of the worm shaft 254 while driving the worm shaft 254. ), A gear mechanism made up of worm shaft bearings 257a and 257b, worm 152, and the like is incorporated in the gear housing 260.

The worm shaft bearings 257a and 257b are mounted inside the gear housing 260 to support the rotation of the worm shaft 254 at both ends of the worm shaft 254 and to reduce the rotational resistance of the worm shaft 254. Where the motor shaft 320 is coupled to the motor boss or damping coupler 330, and the connection portion between the shaft and the shaft via the plug bolt 210, the manufacturing error and assembly error is accumulated to increase the amount of engagement of the bearing As a result, the rotational resistance of the worm shaft 254 is increased.

In addition, when the external force transmitted from the road surface through the wheel and the steering shaft 106 is transmitted to the worm wheel 156, the worm shaft 254 engaged with the worm wheel 156 as well as the axial direction is twisted at a predetermined angle with the axial direction. It causes elastic deformation.

Therefore, in the first embodiment, the motor of the worm shaft 254 may absorb external force transmitted through the worm wheel 156 and vibration and noise generated by friction and wear during operation of the worm 152 and the worm wheel 156. The housing damper 310a is coupled to the opposite end of the coupling portion of the shaft 320. In the second embodiment, the plug damper 310b is coupled to the coupling portion of the worm shaft 254. In the example, the housing damper 310a and the plug damper 310b are respectively coupled to both ends of the worm shaft 254.

The housing damper 310a is a worm shaft 254 that is operated by a worm wheel 156 that rotates in conjunction with a driver's steering wheel and rotates in a forward or reverse direction of a worm shaft 254 engaged with the worm wheel 156. It is absorbed to be transmitted along), worm shaft bearings (257a) coupled to the opposite end of the motor shaft 320 of the worm shaft 254 of the worm shaft bearings (257a, 257b) coupled to both ends of the worm shaft (254) ) And the inner wall of the gear housing 260.

That is, while one side of the housing damper 310a is fixedly supported by the gear housing 260, the outer ring of the worm shaft bearing 257a is supported in the axial direction of the other side by its elastic force to absorb vibrations and noises that are transmitted. .

The housing damper 310a is largely formed of the first support 311, the second support 313, and the elastic support 315, and the first support 311 supports the outer ring of the worm shaft bearing 257a. The second support 313 is supported by the gear housing 260, the elastic support 315 is coupled between the first support 311 while the elastic deformation to compress and relax at a predetermined angle with the axial direction or axial direction Absorb vibration and noise transmitted from the second support 313.

The housing damper 310a is formed between the first support 311 and the second support 313 by injection molding the elastic support 315 in a molten state to form the first support 311 and the first support 311. The two supports 313 and the elastic support 315 are integrally formed, and in some cases, may be formed in an annular shape to facilitate elastic deformation and sound absorption.

That is, the outer diameter of the second support 313 is formed smaller than the outer diameter of the first support 311 while the first support 311 and the second support 313 are formed in an annular shape, and the elastic support 315 is formed therebetween. ) May be coupled to the first support 311 and the second support 313 so that the inner diameter may communicate with each other, and may also be integrally formed by injection molding.

On the other hand, in the second embodiment of the present invention has the same configuration as the first embodiment except for the housing damper (310a), the end portion of the worm shaft bearings (257a, 257b) of the worm shaft 254 connected to the motor shaft 320 The plug damper 310b is coupled between the worm shaft bearing 257b and the plug bolt 210 to be coupled.

One side of the plug damper 310b is fixedly supported by the plug bolt 210 to support the outer ring of the worm shaft bearing 257b with the elastic force in the axial direction of the other side to absorb vibrations and noises that are transmitted.

The plug damper 310b may have a different size for coupling with the plug bolt 210. In addition, the shape and structure, material, manufacturing method, effects of vibration and noise absorption are the same as that of the housing damper 310a. Therefore, the detailed description thereof will be omitted below.

Further, the reduction gear 300c according to the third embodiment of the present invention includes both the housing damper 310a in the first embodiment and the plug damper 310b in the second embodiment.

That is, the housing damper 310a is coupled between the worm shaft bearing 257a and the inner wall of the gear housing 260 coupled to the opposite end of the connection portion of the worm shaft 254 to the motor shaft 320 of the worm shaft 254 of the worm shaft bearing 257a. The outer ring is supported by an elastic force in the axial direction, and the plug damper 310b is coupled between the worm shaft bearing 257b and the plug bolt 210 coupled to the end portion of the motor shaft 320 of the worm shaft 254 and the worm shaft bearing. The outer ring of 257b is supported by the axial elastic force.

Therefore, when the driver manipulates the steering wheel, when the worm wheel 156 rotates in the forward and reverse directions, the worm wheel 156 is engaged with the worm shaft 254 and vibration and noise are transmitted to both ends in the axial direction. Can be simultaneously absorbed at both ends of the worm shaft 254.

Here, the housing damper 310a and the plug damper 310b may vary in size, and in addition, the shape and structure, material, manufacturing method, effects of vibration and noise absorption, etc. are described in the first and second embodiments. Of course, the same as.

Meanwhile, each of the reduction gears according to the first, second and third embodiments of the present invention assists the steering force of the steering wheel through the reduction gear and the motor 146 with reference to FIG. 1. In the electric power assisted steering apparatus, a steering shaft 106 connected to a steering wheel, a steering column for fixing the steering shaft to a vehicle body (see 130 in FIG. 1), and a rotational force input from the steering shaft to linear motion. A rack pinion mechanism including a rack gear and a pinion gear (see 110 in FIG. 1), and a rack bar (see 112 in FIG. 1) provided with tie rods and knuckle arms at both ends thereof constitute an electric power assist steering device. .

Here, the elastic support 315 is NR (Natural Rubber), Nitrile Butadiene Rubber (NBR), Chloroprene Rubber (CR), Ethylene Propylene Terpolymer (EPDM), Fluoro Elastomer (FPM), and SBR (Styrene Butadine) to provide weather resistance and elasticity. Polyacetal (POM) because it is required to be formed of an elastic material such as rubber), CSM (Chlorosulphonated Polyethylene), silicone or the like, or to be formed of a material having a certain bending and rigidity as well as low elasticity by heat as well as wear resistance and low friction resistance. , Polyamide (PA), polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), and the like, and may be formed of an engineering plastics-based material. It may be formed by.

Comparing the speed reducer according to the first embodiment, the second embodiment, and the third embodiment of the present invention with the conventional speed reducer and the rattle noise, as shown in FIG. 5, the rotation angle of the worm shaft on the time axis is As a result of the measurement of the noise in a periodic pattern, the conventional speed reducer reaches a maximum noise of 42 to 43 dB as in the upper graph, but the speed reducer according to the embodiments of the present invention has a maximum noise of 38 to 39 dB as in the lower graph. They stayed low, with a difference of approximately 3 to 5 dB, and a noise value of 40 dB or less, which the driver began to feel as a noise, increasing the driver's steering feeling.

According to embodiments of the present invention having such a shape and structure, the rattle noise caused by the increase in backlash due to the friction and wear of the worm and the worm wheel, or the impact transmitted through the wheel and the steering shaft from the road surface is also reduced, It is effective to increase the driver's steering feeling by reducing the grip and rotational resistance of the worm shaft and the worm shaft bearing.

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.

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.

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, 3B, and 3C are cross-sectional views showing reduction gears of the electric power assisted steering apparatus according to the first, second and third embodiments of the present invention, respectively;

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

Figure 5 is a graph comparing the noise generated in the reducer and the conventional reducer of the electric power assisted steering apparatus according to embodiments 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

257a, 257b: worm shaft bearing 260: gear housing

310a: housing damper 310b: plug damper

311: first support 313: second support

315: elastic support 320: motor shaft

Claims (16)

To absorb vibration and noise caused by friction and wear when the worm shaft and worm wheel are operated, A worm shaft bearing coupled to both ends of the worm shaft to support rotation of the worm shaft; A gear housing accommodating the gear mechanism including the worm shaft, the worm shaft bearing, and the worm wheel; And A housing damper coupled between the worm shaft bearing coupled to the opposite end of the worm shaft bearing of the worm shaft bearing and the inner wall of the gear housing to support the outer ring of the worm shaft bearing with an axial elastic force; Reducer of the electric power assisted steering device, characterized in that it comprises a. The method of claim 1, The housing damper includes a first support for supporting the outer ring of the worm shaft bearing and a second support for supporting the gear housing, and an elastic support is coupled between the first support and the second support. Reducers for electric power assisted steering. The method of claim 2, The housing damper may have the first support having an annular shape, and the second support may also have an annular shape, the outer diameter of which is smaller than that of the first support, and the inner circumferential surface of the first support and the second support may communicate therebetween. Reducer of the electric power assisted steering device, characterized in that the elastic support is coupled. The method of claim 3, wherein The housing damper is a reduction gear of the electric power assist steering device, characterized in that the first support, the second support, and the elastic support are integrally formed. The method of claim 4, wherein The housing damper injection molding the molten elastic support between the first support and the second support to form the first power support, the second support, and the elastic support, wherein the electric power assist steering is integrally formed. Reducer of the device. The method of claim 1, The worm shaft bearing further includes a plug damper coupled between the worm shaft bearing coupled to the end of the motor shaft connecting portion of the third worm shaft and a plug bolt coupled to the worm shaft to support the outer ring of the worm shaft bearing with an axial elastic force. Reducer of the electric power assisted steering apparatus, characterized in that. The method of claim 6, The plug damper includes a first support for supporting an outer ring of the worm shaft bearing and a second support for supporting the plug bolt, and an elastic support is coupled between the first support and the second support. Reducers for electric power assisted steering. The method of claim 7, wherein The plug damper may be formed such that the first support is formed in an annular shape, and the second support is formed in an annular shape, the outer diameter of which is smaller than that of the first support, and the inner circumferential surfaces of the first support and the second support communicate with each other. Reducer of the electric power assisted steering device characterized in that the elastic support is coupled. 9. The method according to claim 7 or 8, The plug damper may injection molding the elastic support melted between the first support and the second support to integrally form the first support, the second support and the elastic support. Reducer. To absorb vibration and noise caused by friction and wear when the worm shaft and worm wheel are operated, A worm shaft bearing coupled to both ends of the worm shaft to support rotation of the worm shaft; A gear housing accommodating the gear mechanism including the worm shaft, the worm shaft bearing, and the worm wheel; And A plug damper coupled between a worm shaft bearing coupled to an end portion of the worm shaft bearing of the worm shaft bearing and a plug bolt coupled to the worm shaft to support an outer ring of the worm shaft bearing with an axial elastic force; Reducer of the electric power assisted steering device, characterized in that it comprises a. 11. The method of claim 10, The plug damper may be formed such that the first support is formed in an annular shape, and the second support is formed in an annular shape, the outer diameter of which is smaller than that of the first support, and the inner circumferential surfaces of the first support and the second support communicate with each other. Reducer of the electric power assisted steering device characterized in that the elastic support is coupled. The method of claim 11, The plug damper may injection molding the elastic support melted between the first support and the second support to integrally form the first support, the second support and the elastic support. Reducer. In the electric power assist steering device for assisting the steering force of the steering wheel through the reducer and the motor, The reducer, To absorb vibration and noise caused by friction and wear when the worm shaft and worm wheel are operated, A worm shaft bearing coupled to both ends of the worm shaft to support rotation of the worm shaft; A gear housing accommodating the gear mechanism including the worm shaft, the worm shaft bearing, and the worm wheel; And A housing damper coupled between the worm shaft bearing coupled to the opposite end of the worm shaft bearing of the worm shaft bearing and the inner wall of the gear housing to support the outer ring of the worm shaft bearing with an axial elastic force; Electric power assisted steering, characterized in that it comprises a. The method of claim 13, The housing damper includes a first support for supporting the outer ring of the worm shaft bearing and a second support for supporting the gear housing, and an elastic support is coupled between the first support and the second support. Electric power assisted steering. The method of claim 13, The worm shaft bearing further includes a plug damper coupled between the worm shaft bearing coupled to the end of the motor shaft connecting portion of the third worm shaft and a plug bolt coupled to the worm shaft to support the outer ring of the worm shaft bearing with an axial elastic force. Electric power assisted steering, characterized in that. The method of claim 15, The plug damper includes a first support for supporting an outer ring of the worm shaft bearing and a second support for supporting the plug bolt, and an elastic support is coupled between the first support and the second support. Electric power assisted steering.

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