KR101218866B1

KR101218866B1 - Rack Assist Type Electric Power Steering System

Info

Publication number: KR101218866B1
Application number: KR1020100091065A
Authority: KR
Inventors: 조희권; 김동완
Original assignee: 주식회사 만도
Priority date: 2010-09-16
Filing date: 2010-09-16
Publication date: 2013-01-07
Also published as: KR20120029152A

Abstract

The present invention relates to a rack type electric power assisted steering device.
The present invention comprises a rack housing for forming a through-hole on one side and surrounding the rack bar and the ball screw; A motor pulley housing slidably mounted to the rack housing while being fixed to the through hole of the rack housing; And a belt configured to transfer the rotational force of the motor to the rack bar through a driving pulley mounted at an end of the motor shaft.
According to the present invention, the inclined portion of the motor pulley housing slides along the inner circumferential surface of the through-hole of the rack housing, and the motor pulley housing is coupled to the rack housing, thereby increasing the tension of the belt by the step between the guide portion and the fixing portion, thereby generating noise and It is effective in preventing damage.

Description

Rack Assist Type Electric Power Steering System

The present invention relates to a rack type electric power assisted steering device. More specifically, the inclined portion of the motor pulley housing slides along the inner circumferential surface of the through hole of the rack housing, and the motor pulley housing is coupled to the rack housing, thereby increasing the tension of the belt by the step between the guide portion and the fixing portion, thereby generating noise and The present invention relates to a rack-type electric power assisted steering device capable of preventing damage in advance.

The steering device is a device that allows the driver to freely change the driving direction of the car by turning the steering wheel. The steering device is a device that assists the driver in advancing the car in a desired direction by arbitrarily changing the rotation center of the car's front wheel.

To steer the wheels while the vehicle is stationary, the steering wheel must be turned with a force greater than the friction between the wheels and the road surface.In particular, when the weight of the car is large and the wheels are wide, Steering power is further increased.

In this steering system, a power steering system is added to relieve the driver's power, and the automobile power assist steering system is a hydraulic power steering system using hydraulic pressure of a hydraulic pump. Has been used, but since 1990, the electric power steering apparatus (Electric Power Steering Apparatus) using the electric motor is becoming more and more common.

Conventional hydraulic power assisted steering system consumes energy at all times regardless of whether the steering wheel is rotated by the hydraulic pump driven by the engine. When generated, a motor driven by electrical energy provides steering assistance power. Therefore, when the electric power assisted steering device is used, energy efficiency can be improved compared to the hydraulic power assisted steering device.

1 is a block diagram of a rack-type electric power assisted steering device of a vehicle according to the prior art.

As shown in FIG. 1, a rack type electric power assisted steering device of a vehicle generally provides steering assistance power to the steering system 100 and the steering system 100 that extend from the steering wheel 101 to both wheels 108. It is configured to include an auxiliary power mechanism 120.

The steering system 100 has one side connected to the steering wheel 101 to rotate together with the steering wheel 101 and the other side to the steering shaft 102 connected to the pinion shaft 104 via a pair of universal joints 103. It is configured to include). In addition, the pinion shaft 104 is connected to the rack bar 109 through the rack-pinion mechanism 105, and both ends of the rack bar 109 are connected to the wheels 108 of the vehicle through the tie rod 106 and the knuckle arm 107. )

The rack-pinion mechanism part 105 is formed by engaging the pinion gear part 111 formed on the pinion shaft 104 and the rack gear part 112 formed on one side of the outer circumferential surface of the rack bar 109 with each other. When the 101 is operated, torque is generated in the steering system 100, and the wheel 108 is steered through the rack-pinion mechanism 105 and the tie rod 106 by the generated torque.

The auxiliary power mechanism 120 senses the torque applied by the driver to the steering wheel 101 and outputs an electric signal proportional to the sensed torque, based on an electric signal transmitted from the torque sensor 121 and the torque sensor 121. Electronic control unit (ECU) 123 for generating control signals, motor 130 for generating auxiliary power based on control signals transmitted from electronic control device 123 and motor 130 via a belt It is configured to include a belt-type transmission device for transmitting the auxiliary power generated in the rack bar 109.

Accordingly, in the rack type electric power assisted steering device, torque generated by the rotation of the steering wheel 101 is transmitted to the rack bar 109 via the rack-pinion mechanism 105, and is generated in the motor 130 according to the generated torque. Auxiliary power is formed to be transmitted to the rack bar 109 via the ball screw unit 150 by the belt-type transmission (140). That is, the torque generated from the steering system 100 and the auxiliary power generated from the motor 130 are combined to move the rack bar 109 in the axial direction.

2 is a partial cross-sectional view of a rack-type electric power assisted steering device according to the prior art.

As shown in FIG. 2, the rack type electric power assisted steering device according to the related art includes a rack bar 109 extending in a horizontal direction of a vehicle and forming a rack gear part on one side of an outer circumferential surface thereof, and a pinion gear part engaged with the rack gear part. The ball screw part 150, the ball nut 205, and the motor shaft 221, which are composed of a pin nut shaft 104 and a ball nut 205 engaged with the ball screw 203 through the ball 201, are provided. The belt-type transmission device 140 and the motor 130 are connected to each other, and the motor pulley housing 240 surrounds the motor and is fixed to the rack housing 223 by bolt coupling.

The pinion shaft 104 is connected to a steering wheel through a steering shaft, and a rack bar 109 having a predetermined length of screw formed on one side of an outer circumferential surface thereof is embedded in the rack housing 223.

The ball screw part 150 is formed coaxially with the rack bar 109 but is in contact with the ball nut 205 surrounding the rack bar 109 and the ball screw 203 formed on the outer circumferential surface of the rack bar 109. It is configured to include). The ball nut 205 rotates as the motor shaft 221 rotates. The bearing 207 is disposed between the outer circumferential surface of the ball nut 205 and the inner circumferential surface of the rack housing 223 for smooth rotation of the ball nut 205. Is provided.

The belt-type transmission device 140 includes a belt 230 connecting the motor shaft 221 and the ball nut 205 to each other, and is generated in the motor 130 in proportion to the steering torque applied to the steering wheel. Power is transmitted to the rack bar 109 through the ball nut 205. That is, as the motor shaft 221 rotates, the ball nut 205 which receives the rotational force of the motor shaft 221 by the belt 230 also rotates, and the ball 201 and the ball nut 205 rotate. According to the movement of the ball screw 203, the rack bar 109 is to make a linear movement in the axial direction.

3 is a side view of a motor pulley housing and a rack housing according to the prior art.

The motor 130 is fixed by the motor pulley housing 240 surrounding the motor 130 and the bolt 300 of the rack housing 223. When the motor shaft 221 rotates to steer the ball 230 by rotating the ball nut 205 while steering, the rack bar having the motor shaft 221 and the ball nut 205 by the tension of the belt 230. Forces act in the directions in which the axes of 109 pull each other. The force generated as above is concentrated to the coupling portion of the bolt pulley 300 of the motor pulley housing 240 and the rack housing 225, which is the weakest part mechanically, while the steering and vibration generated when the motor shaft 221 rotates. Due to the loosening of the bolt 300, the motor shaft 221 moves toward the rack bar 109 having the ball nut 205, thereby lowering the tension of the belt 230 and causing the belt 230 and the driving pulley 310 to move. ), Noise is generated between the driven pulley 320 and there is a problem that the belt 230 is damaged.

In order to solve the above-mentioned problems, the present invention provides a rack type electric power assisted steering device, wherein the inclined portion of the motor pulley housing slides along the inner circumferential surface of the through hole of the rack housing so that the motor pulley housing is coupled to the rack housing, thereby providing a guide portion and a high-speed guide. It is an object of the present invention to provide a rack-type electric power assisted steering device that can increase the tension of the belt by the government step, thereby preventing noise and damage to the belt.

In order to achieve the above object, the present invention provides a through-hole formed on one side and a rack housing surrounding the rack bar and the ball screw; The motor wraps around the motor and includes a fixed part through which the motor shaft penetrates and an inclined part whose outer diameter decreases from the end of the fixed part. The sliding part is slid along the inclined part and the fixing part is seated in the through hole of the rack housing. A motor pulley housing mounted; And a belt for transmitting the rotational force of the motor to the rack bar through a driving pulley mounted at an end of the motor shaft, wherein the inclined portion of the motor pulley housing has a conical cone shape or a high cone whose outer diameter decreases from the end of the fixing portion. It is formed in a shape that the outer diameter is reduced in the shape of a gentle cross section from the end of the government, and provided with a guide portion formed in a constant diameter at the end of the inclined portion, the tension of the belt by the step of the fixing portion and the guide portion It provides a rack type electric power assisted steering device, characterized in that coupled to this increased state.

As described above, according to the present invention, the inclined portion of the motor pulley housing slides along the inner circumferential surface of the through hole of the rack housing, and the motor pulley housing is coupled to the rack housing, thereby increasing the tension of the belt by the step between the guide portion and the fixing portion. It is effective in preventing noise generation and damage to the belt.

1 is a block diagram of a rack-type electric power assisted steering device of a vehicle according to the prior art.
2 is a partial cross-sectional view of a rack-type electric power assisted steering device according to the prior art.
3 is a side view of a motor pulley housing and a rack housing according to the prior art.
4 is a partial cross-sectional view of the rack-type electric power assisted steering device according to the present invention.
5 is a cross-sectional view showing a coupling sequence of the motor pulley housing and the rack housing according to the present invention.
6 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a second embodiment of the present invention.
7 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a third embodiment of the present invention.
8 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a fourth embodiment of the present invention.
9 is a cross-sectional view showing a coupling sequence of a motor and a rack housing according to a fourth embodiment of the present invention.
10 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a fifth embodiment of the present invention.
11 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a sixth embodiment of the present invention.

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."

In the rack-type electric power assisted steering device, torque generated by the rotation of the steering wheel is transmitted to the rack bar through the rack-pinion mechanism part, and auxiliary power generated from the motor is passed through the ball screw part by the belt-type transmission in accordance with the generated torque. It is formed to be delivered to the bar. That is, the torque generated from the steering system and the auxiliary power generated from the motor are combined to move the rack bar in the axial direction.

4 is a partial cross-sectional view of the rack-type electric power assisted steering device according to the present invention.

As shown in FIG. 4, the motor 130 has a motor shaft 221 extending outward. In addition, a driving pulley 310 is mounted at an end of the motor shaft 221, and the driving pulley 310 is rotated when the motor shaft 221 rotates.

The belt 230 is wound around the driving pulley 310 and the driven pulley 320, but when the motor 130 rotates, the motor shaft 221, the driving pulley 310, the belt 230, and the driven pulley 320 are rotated. The ball nut 205 also receives the rotational force of the motor 130 through the rotation, and as the ball nut 205 rotates, the rack bar 109 is linearly moved in the axial direction.

The rack housing 225 surrounds the rack bar 109, and seats the ball nut 205 surrounding the rack bar 109, but the outer circumferential surface of the ball nut 205 and the rack housing 223 for smooth rotation of the ball nut 205. A bearing 207 is provided between the inner circumferential surfaces of

One side of the rack housing 225 is formed with a through hole 430 in the axial direction of the rack bar 109 and the motor pulley housing 240 surrounding the motor 130 in the through hole 430 is inserted into the bolt coupling Is fixed by.

The motor pulley housing 240 surrounds the motor 130 and has a cylindrical outer diameter smaller than that of the fixing part 420 and the fixing part 420 through which the motor shaft 221 penetrates in a cylindrical shape, and has a tapered shape. Guide portion 410 is connected to the inclined portion 400.

The cylindrical fixing part 420 formed at one side of the motor pulley housing 240 has an outer diameter for insertion into the through hole 430 of the rack housing 225, and a driving pulley at an end of the motor shaft 221 penetrated. 310 is attached, and the drive pulley 310 is rotated when the motor shaft 221 rotates.

The length L1 of the driving pulley 310 is formed to be 1.5 times longer than the width L2 of the belt 230, and the length L1 of the driving pulley 310 is a guide part of the motor pulley housing 240. When the 410 is inserted into the through hole 430 of the rack housing 250, a part of the belt 230 is formed to be wound on the driving pulley 310.

5 is a cross-sectional view showing a coupling sequence of the motor pulley housing and the rack housing according to the present invention.

The auxiliary power generated by the motor 130 is transmitted to the rack bar 109 in proportion to the steering torque applied to the steering wheel. That is, as the motor shaft 221 rotates, the ball nut 205 which receives the rotational force of the motor shaft 221 by the belt 230 also rotates, and the rack bar 109 rotates as the ball nut 205 rotates. Linear motion in the axial direction.

However, when the tension of the belt 230 is weak, the rotational movement of the motor 130 is not properly transmitted to the rack bar 109.

Accordingly, in order to increase the tension of the belt 230, first, as shown in FIG. 5, the guide part 410 of the motor pulley housing 240 is inserted into the through hole 430 of the rack housing 225, and then the belt 230 is removed. A part of) is wound on the driving pulley 310.

When the motor pulley housing 240 surrounding the motor 130 is inserted into the through hole 430 using the assembly jig 500, the motor pulley housing 240 slides along the inclined portion 400 of the motor pulley housing 240 to rack. Seated in the housing 225, when the inclined portion 400 of the motor pulley housing 240 is slid to the rack housing 225, the motor shaft 221 and the rack bar 109 away from the belt 230 Tension is increased. That is, the distance "A" between the motor shaft 221 and the rack bar 109 before the inclined portion 400 of the motor pulley housing 240 is slid to the rack housing 225 is the inclined portion 400 of the motor pulley housing 240. ) Is moved away from the motor shaft 221 and the rack bar 109 at a distance "B" when it is seated by sliding in the rack housing 225.

Therefore, the distance between the driving pulley 310 and the driven pulley 320 is increased by the step of the fixing part 420 of the motor pulley housing 240 and the guide part 410 connected to the inclined part 400. ) Tension is kept increased.

6 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a second embodiment of the present invention.

The motor pulley housing 240 surrounds the motor 130 and has a conical cone-shaped taper whose outer diameter decreases from the end of the fixing part 420 and the fixing part 420 through which the motor shaft 221 penetrates in a cylindrical shape on one side. It may be made of a true inclined portion (400).

When the motor pulley housing 240 surrounding the motor 130 is inserted into the through hole 430 using the assembly jig 500, the motor pulley housing 240 slides along the inclined portion 400 of the motor pulley housing 240 to rack. Seated in the housing 225, when the inclined portion 400 of the motor pulley housing 240 is slid to the rack housing 225, the motor shaft 221 and the rack bar 109 away from the belt 230 Tension is increased.

7 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a third embodiment of the present invention.

The motor pulley housing 240 surrounds the motor 130 and draws a gentle curve in cross section from the end of the fixing part 420 and the fixing part 420 through which the motor shaft 221 penetrates in a cylindrical shape on one side, and has an outer diameter. It may be made of an inclined portion 400 having a smaller shape.

8 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a fourth embodiment of the present invention.

Looking at the rack-type electric power assisted steering apparatus according to the fourth embodiment with reference to Figure 8, the shape of the motor 130 and the motor pulley housing 240 is formed integrally different from the above embodiment.

As shown in FIG. 8, the motor 130 has a motor shaft 221 extending outward. In addition, a driving pulley 310 is mounted at an end of the motor shaft 221, and the driving pulley 310 is rotated when the motor shaft 221 rotates.

One side of the rack housing 225 is formed with a through hole 430 in the axial direction of the rack bar 109, the motor 130 is inserted into the through hole 430 is fixed by bolt coupling.

The motor 130 has a cylindrical outer diameter smaller than that of the fixed part 420 and the fixed part 420 through which the motor shaft 221 penetrates in a cylindrical shape on one side, and is connected to the tapered inclined part 400. It consists of a portion (410).

The cylindrical fixing part 420 formed at one side of the motor 130 has an outer diameter for insertion into the through hole 430 of the rack housing 225, and the driving pulley 310 at the end of the motor shaft 221 to be penetrated. ) Is mounted, and the drive pulley 310 is rotated when the motor shaft 221 rotates.

9 is a cross-sectional view showing a coupling sequence of a motor and a rack housing according to a fourth embodiment of the present invention.

Therefore, in order to increase the tension of the belt 230, first, as shown in FIG. 9, the guide part 410 of the motor 130 is inserted into the through hole 430 of the rack housing 225, and then the belt 230 of the belt 230 is removed. A part is wound around the drive pulley 310.

When the motor 130 is inserted into the through hole 430 using the assembly jig 500, the motor 130 slides along the inclined portion 400 of the motor 130 and is seated on the rack housing 225. When the inclined portion 400 of the 130 is slid to the rack housing 225, the distance between the motor shaft 221 and the rack bar 109 is increased, the tension of the belt 230 is increased. That is, the distance "A" between the motor shaft 221 and the rack bar 109 before the inclined portion 400 of the motor 130 slides on the rack housing 225 is the inclined portion 400 of the motor 130. When it is slid to and seated at 225, the motor shaft 221 and the rack bar 109 away from the distance "B" state.

Accordingly, the distance between the driving pulley 310 and the driven pulley 320 is increased by the step difference between the fixing part 420 of the motor 130 and the guide part 410 connected to the inclined part 400 of the belt 230. The tension is kept increased.

10 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a fifth embodiment of the present invention.

The motor 130 is composed of a fixed portion 420 through which the motor shaft 221 penetrates in one side and a tapered inclined portion 400 having a conical cone shape whose outer diameter decreases from the end of the fixing portion 420. Can be.

When the motor 130 is inserted into the through hole 430 using the assembly jig 500, the motor 130 slides along the inclined portion 400 of the motor 130 and is seated on the rack housing 225. When the inclined portion 400 of the 130 is slid to the rack housing 225, the distance between the motor shaft 221 and the rack bar 109 is increased, the tension of the belt 230 is increased.

11 is a partial cross-sectional view of a rack-type electric power assisted steering device according to a sixth embodiment of the present invention.

The motor 130 has an inclined portion 400 having a cylindrical shape on one side and a fixed section 420 through which the motor shaft 221 penetrates and a smooth cross section from the end of the fixing portion 420, and the outer diameter of which is reduced. It can be made of).

As described above, according to the present invention, the inclined portion of the motor pulley housing slides along the inner circumferential surface of the through hole of the rack housing, and the motor pulley housing is coupled to the rack housing, thereby increasing the tension of the belt by the step of the engaging portion and the seating portion. It is effective in preventing noise and damage to the belt.

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. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

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 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.

100: steering system 101: steering wheel
102: steering shaft 103: universal joint
104: pinion shaft 105: rack-pinion mechanism
106: tie rod 107: knuckle arm
108: wheel 109: rack bar
111: pinion gear portion 112: rack gear portion
120: auxiliary power mechanism 130: motor
140: belt type transmission device 150: ball screw portion
201: ball 203: ball screw
205: ball nut 207: bearing
223 rack housing 230 belt
240: motor pulley housing 300: bolt
310: driven pulley 320: driven pulley
400: inclined portion 410: guide portion
420: fixed part 430: through hole
500: assembly jig

Claims

A through hole is formed on one side and the rack housing surrounding the rack bar and the ball screw;
The motor wraps around the motor and includes a fixed portion through which the motor shaft penetrates and an inclined portion whose outer diameter decreases from the end of the fixed portion. A motor pulley housing mounted; And
A belt for transmitting the rotational force of the motor to the rack bar through a driving pulley mounted at an end of the motor shaft;
, &Lt; / RTI >
The inclined portion of the motor pulley housing is formed in the shape of a cone cone, the outer diameter of which is reduced from the end of the fixing portion or a shape of which the outer diameter is small, drawing a gentle curve from the end of the fixing portion.
And a guide part having a constant diameter formed at the end of the inclined part, wherein the tension of the belt is increased by a step between the fixing part and the guide part.

delete

The method of claim 1,
The drive pulley is a rack-type electric power assisted steering device characterized in that when the coupling of the motor pulley housing and the rack housing is formed to a length that the belt can be mounted in a state where the guide portion is located at the end of the through hole.

The method of claim 1,
The drive pulley is a rack type electric power assisted steering device, characterized in that formed more than 1.5 times longer than the width of the belt.

A through hole is formed on one side and the rack housing surrounding the rack bar and the ball screw;
A motor mounted to the rack housing while the fixed shaft through which the motor shaft penetrates, and an inclined portion whose outer diameter decreases from the end of the fixing portion, is slid along the inclined portion and is seated in the through hole of the rack housing; And
A belt for transmitting the rotational force of the motor to the rack bar through a driving pulley mounted at an end of the motor shaft;
, &Lt; / RTI >
The inclined portion of the motor is formed in a cone cone shape of the outer diameter is reduced from the end of the fixed portion or a shape of the outer diameter is reduced with a gentle cross section from the end of the fixed portion,
And a guide part having a constant diameter formed at the end of the inclined part, wherein the tension of the belt is increased by a step between the fixing part and the guide part.

delete

The method of claim 7, wherein
The drive pulley is a rack type electric power assisted steering device, characterized in that formed when the coupling of the motor and the rack housing the length of the belt can be mounted in the state where the guide portion is located at the end of the through hole.