KR20100000747A - Clearance compensating reduction device and electronical power steering apparatus having the same - Google Patents

Abstract

PURPOSE: A clearance compensating reducer and an electric power assist steering apparatus with the same are provided to reduce rattle noises by using a worm shaft having elasticity and to reduce the number of parts and work time by removing the need pin coupling between the worm shaft and a motor shaft. CONSTITUTION: A clearance compensating reducer(300) comprises a motor shaft(310) in which a worm shaft is inserted, a wave washer which is fitted to one end of a bearing and mounted in a motor housing(320), an elastic worm shaft(370) in which a worm(152) meshed with a worm wheel(156) is formed and which is fitted to the motor shaft to compensates the distance to the worm wheel resulting from the abrasion of the worm, and a support ring(380) which is formed on the inner end of a gear housing to support the rotation of the worm shaft.

Description

Gap Compensating Reduction Device and Electronic Power Steering Apparatus Having The Same}

The present invention relates to a clearance compensation reducer and an electric power assisted steering apparatus having the same. More specifically, the worm shaft of the reducer is formed of an elastic body to compensate for the clearance between the worm and the worm wheel by the elastic force of the worm shaft, thereby reducing rattle noise, pin-coupled the worm shaft and the motor shaft, and the noise, bearing, damping coupler and plug. The present invention relates to a clearance compensation reducer capable of reducing the number of parts, reducing work time, and lowering manufacturing costs by eliminating the process of fastening bolts and plug nuts, and the like, and an electric power assisted steering device having the same.

The steering device of the vehicle allows the driver to freely change the direction of travel of the vehicle by turning the steering wheel, and assists the driver in advancing the vehicle in the desired direction by arbitrarily changing the rotation center of the vehicle's front wheels. Device. In this steering system, a power steering system is used as an auxiliary power mechanism to relieve the driver's power. The power steering system uses a large amount of engine power to operate a hydraulic pump to assist steering power. There are hydraulic power assist steering using hydraulic power and electric power assist steering using electric motor.

The hydraulic power assist steering device senses the rotation of the steering wheel and receives the rotational force from the engine to operate the hydraulic pump and sends the hydraulic pressure to a drive such as a cylinder configured on the rack bar or steering shaft to assist the driver's steering power.

The electric power assisted steering device detects the rotation of the steering wheel and is installed on the rack or steering shaft to operate a motor that assists the rotational movement so that the steering device operates smoothly. The electric power assisted steering device is largely rack driven. There are two types (R-EPS) and steering shaft drive type (C-EPS).

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 of a reducer of the 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 first ball bearings at both ends of the worm shaft 254. And second ball bearings 257 and 258 are respectively installed to support the worm shaft 254, and the plug bolt 210 is damped to prevent the second ball bearing 258 from being spaced in the axial direction of the worm shaft 254. It is fastened between the coupler 240 and the second ball bearing 258, and the plug bolt 210 is fixed by the plug nut 220.

The worm shaft 254 is connected to the motor shaft 245 and the damping coupler 240 to have a structure in which the worm shaft 254 is rotated by the 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 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 conventional speed reducer having such a structure has a problem in that rattle noise occurs when a worm or worm wheel is worn due to vehicle driving conditions, and a large number of bearings supporting the worm shaft and the motor shaft have a problem in that operating noise increases.

In addition, the damping coupler connecting the worm shaft and the motor shaft should be tightened, and the plug bolt is additionally tightened to prevent the axial play of the second ball bearing, and the plug nut is tightened to fix the plug bolt again. Increasing time has a problem that the manufacturing cost increases and the work efficiency decreases.

In order to solve this problem, the present invention can form a worm shaft with an elastic body to compensate for the clearance between the worm and the worm wheel by the elastic force of the worm shaft, thereby reducing rattle noise, and pin-bonding the worm shaft and the motor shaft, and damping bearings and damping. The purpose of the present invention is to provide a clearance compensation reducer capable of reducing the number of parts, working time and manufacturing cost by eliminating the process of fastening coupler, plug bolt and plug nut, and an electric power assisted steering device having the same. .

In order to achieve the above object, the present invention includes a motor shaft formed in a hollow cylindrical shape so that the worm shaft is inserted and coupled therein; A wave washer inserted into one end of a bearing supporting the motor shaft to be compensated for the axial play of the motor shaft and seated in the motor housing; A worm shaft which is formed with a worm wheel and engaged with the worm wheel, and is inserted into and coupled to the motor shaft and formed of an elastic member to compensate for play with the worm wheel due to wear of the worm; And a support ring seated at an inner end of the gear housing including the worm and the worm wheel, and inserted into one end of the worm shaft to support rotation of the worm shaft.

In addition, the present invention includes a steering shaft, one side of which is connected to the steering wheel to rotate together with the steering wheel and the other side of which is connected to the pinion shaft via a pair of universal joints; A rack-pinion mechanism for connecting said pinion shaft to a rack bar; A torque sensor which senses torque applied to the steering wheel and outputs an electrical signal proportional to the sensed torque; An electronic control device for generating a control signal based on the electrical signal transmitted from the torque sensor; A motor that generates auxiliary power based on a control signal transmitted from the electronic control device; And a play compensation reducer for transmitting the auxiliary power generated from the motor to the steering shaft.

According to the present invention, the worm shaft of the reducer is formed of an elastic body to compensate for the clearance between the worm and the worm wheel by the elastic force of the worm shaft, thereby reducing rattle noise, pin-coupled the worm shaft and the motor shaft, and a high noise bearing, damping coupler, Since the process of fastening the plug bolt and the plug nut can be eliminated, the manufacturing cost can be reduced by reducing the number of parts and shortening the working time.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

3 is a cross-sectional view showing a play compensation reducer according to an embodiment of the present invention.

As shown in FIG. 3, the clearance compensation reducer 300 according to the embodiment of the present invention includes a motor shaft 310 formed in a hollow cylindrical shape such that the worm shaft 370 is inserted into and coupled thereto; A wave washer (350) inserted into one end of the second bearing (340) supporting the motor shaft (310) to be compensated for the axial play of the motor shaft (310) and seated on the motor housing (320); A worm shaft 152 which is engaged with the worm wheel 156 is formed and inserted into and coupled to the motor shaft 310, and a worm shaft formed of an elastic member so as to compensate for play with the worm wheel 156 due to wear of the worm 152. 370); And a support ring 380 seated at an inner end of the gear housing 260 having the worm 152 and the worm wheel 156 therein and inserted into one end of the worm shaft 370 to support rotation of the worm shaft 370. It is configured to include.

On the other hand, the electric power assisted steering device having a clearance compensation reducer 300 according to an embodiment of the present invention, one side is connected to the steering wheel (see 102 in FIG. 1) rotates with the steering wheel and the other side is a pair of universal A steering shaft 106 connected to the pinion shaft (see 108 in FIG. 1) via a joint (see 104 in FIG. 1); A rack-pinion mechanism part (see 110 in FIG. 1) for connecting the pinion shaft to the rack bar; A torque sensor (see 142 of FIG. 1) for detecting torque applied to the steering wheel and outputting an electrical signal proportional to the sensed torque; An electronic control device (see 144 in FIG. 1) for generating a control signal based on the electrical signal transmitted from the torque sensor; A motor 146 for generating auxiliary power based on a control signal transmitted from the electronic control apparatus; And a clearance compensation reducer 300 for transmitting auxiliary power generated from the motor 146 to the steering shaft 106.

The clearance compensation reducer 300 according to the embodiment of the present invention is configured to compensate the clearance between the worm 152 and the worm wheel 156 by the elastic force of the worm shaft 370.

Accordingly, the worm shaft 370 is formed of spring steel such as SPS, or carbon steel such as SM45C, and the worm shaft 370 has a clearance amount (about 100 micrometers or less) generated when the worm 152 or the worm wheel 156 is worn. Compensation is made while bending within this elastic strain limit.

Both ends of the worm shaft 370 are supported by the gear housing support 390 and the motor housing support 395.

That is, the gear housing support 390 is supported by a support ring seated on the inner end of the gear housing 260 in which the worm 152 and the worm wheel 156 are embedded. In the motor housing support 395, the motor housing ( It is supported by the second bearing 340 and wave washer 350 at the inner end of 320.

In this way, the worm shaft 370 supported at both ends is formed at one side with a worm 152 engaged with the worm wheel 156 rotated in conjunction with the steering shaft 106, and the other side is in the motor shaft 310. The small diameter portion 373 is inserted into the inner circumferential surface of the motor shaft 310 to form a predetermined gap, and the large diameter portion 375 is formed to be tightly inserted into and coupled to the inner circumferential surface of the motor shaft 310.

The motor shaft 310 is formed in a hollow cylindrical shape so that the worm shaft 370 is inserted into and coupled to the inside thereof, and a pinhole is formed at the end of the motor housing 320 to be coupled to the worm shaft 370 and the pin 360. The end is supported by the first bearing 345, and the other end is supported by the second bearing 340 and the wave washer 350.

However, the present invention is not limited thereto, and in some cases, the motor shaft 310 and the worm shaft 370 may be coupled to the motor shaft 310 by pressing the worm shaft 370 into the motor shaft 310 instead of being coupled to the pin 360.

When the worm shaft 370 is inserted into the inside of the motor shaft 310 to be pin 360 or press-fitted and supported at both sides, when assembling the gear housing 260, the motor cover 330, the motor housing 320, and the like, Both ends of the worm shaft 370 are supported by the gear housing support 390 and the motor housing support 395 so that the worm 152 and the worm wheel 156 receive close contact with each other and are bent within the elastic range. It will be assembled as it is built.

Therefore, in the state where the clearance compensation reducer 300 is finally assembled, the worm shaft 370 is in close contact while applying a force to the worm wheel 156 by an elastic force, and the durability of the worm 152 or the worm wheel 156 is advanced. Even if worn out, the play is compensated for by the elastic force.

The wave washer 350 is inserted into one end of the second bearing 340 supporting the motor shaft 310 to compensate for the axial play between the motor shaft 310 and the worm shaft 370, and thus is inserted into the motor housing 320. While seated, the shape of the wave washer 350 protruding or recessed in the axial direction of the motor shaft 310 is elastically deformed and supported by the motor housing 320 to compensate for the clearance in the direction of the motor shaft 310.

The support ring 380 supporting one end of the worm shaft 370 is seated on the inner housing gear housing support 390 of the gear housing 260 in which the worm 152 and the worm wheel 156 are embedded, and the worm shaft 370. Is inserted into one end of the to support the rotation of the worm shaft 370.

The support ring 380 supporting one end of the worm shaft 370 is formed of an elastic rubber or silicone, urethane, or the like, and supports the worm shaft 370 when the worm shaft 370 is bent within an elastic range. By adding an elastic force of the support ring 380 itself to compensate the play of the worm 152 and the worm wheel 156 together with the worm shaft 370.

In order to reduce the friction caused by the rotational contact of the worm shaft 370 between the support ring 380 and the worm shaft 370, the worm shaft contact portion of the support ring 380 is coated with a low friction material, or a low acetal (POM) Bush 383 formed of a friction material is inserted to reduce friction resistance and wear with the worm shaft 370.

In addition, an intermediate portion where the worm shaft 370 and the motor shaft 310 are coupled may further include an elastic ring 385 between the worm shaft 370 and the empty space of the motor shaft 310. ) Is inserted between the worm shaft 370 and the motor shaft 310 to further support the intermediate portion of the worm shaft 370.

According to the present invention having the structure and shape as described above, the worm shaft of the reducer may be formed of an elastic body to compensate for the clearance between the worm and the worm wheel by the elastic force of the worm shaft, thereby reducing rattle noise.

In addition, it eliminates the process of fastening bearings, damping couplers, plug bolts, and plug nuts that are noisy with pin coupling of the worm shaft and the motor shaft, thereby reducing the number of parts, reducing the working time, and reducing the manufacturing cost. .

The above description is merely illustrative of the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential features of the present invention. Accordingly, the embodiments disclosed herein are not intended to limit 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 same 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 of a reducer of a conventional electric power assisted steering device;

3 is a cross-sectional view showing a play compensation reducer according to an embodiment of the present invention.

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

106: steering wheel 146: motor

152: worm 156: worm wheel

310: motor shaft 320: motor housing

330: motor cover 340: second bearing

345: first bearing 350: wave washer

360: pin 370: worm shaft

373: small neck 375: large neck

380: support ring 383: bush

390: gear housing support 395: motor housing support

Claims (7)

A motor shaft formed in a hollow cylindrical shape such that the worm shaft is inserted into and coupled to the worm shaft; A wave washer inserted into one end of a bearing supporting the motor shaft to be compensated for the axial play of the motor shaft and seated in the motor housing; A worm shaft which is formed with a worm wheel and engaged with the worm wheel, and is inserted into and coupled to the motor shaft and formed of an elastic member to compensate for play with the worm wheel due to wear of the worm; And A support ring seated at an inner end of a gear housing that houses a worm and a worm wheel, and inserted into one end of the worm shaft to support rotation of the worm shaft; Spacing compensation reducer, characterized in that comprising a. The method of claim 1, The worm shaft is a gap compensation reducer, characterized in that the motor shaft is pressed or coupled to the pin. The method of claim 1, And a resilient ring inserted between the motor shaft and the worm shaft supported by the bearing outside the motor housing to support the worm shaft by an elastic force. The method of claim 1, When the worm shaft is assembled with the worm wheel, the gear housing, and the motor housing, both ends of the worm shaft are supported at the gear housing support and the motor housing support so that the worm and the worm wheel face each other and are tightly assembled so that the worm shaft is bent within an elastic range. Spacing compensation reducer, characterized in that assembled. The method of claim 1, The support ring is formed of a rubber or silicon or urethane material to support the worm shaft by the elastic force and the friction compensation reducer, characterized in that the coating of the low friction material is formed on the contact portion with the worm shaft. The method of claim 1, The gap compensation reducer is inserted between the support ring and the worm shaft is formed of a low friction material. A steering shaft having one side connected to the steering wheel to rotate together with the steering wheel and the other side connected to the pinion shaft via a pair of universal joints; A rack-pinion mechanism for connecting the pinion shaft to the rack bar; A torque sensor that senses torque applied to the steering wheel and outputs an electrical signal proportional to the sensed torque; An electronic control device that generates a control signal based on the electrical signal transmitted from the torque sensor; A motor that generates auxiliary power based on a control signal transmitted from the electronic control device; And The clearance compensation reducer according to any one of claims 1 to 5, which transmits the auxiliary power generated by the motor to a steering shaft. Steering device having a gap compensation reducer, characterized in that comprising a.

Images