KR20140006284A - Rack - motor driven power steering system and assembling method thereof - Google Patents

Abstract

The present invention relates to a rack-motor driven power steering system (R-MDPS) is combined with a rack bar (3a) arranged to a length direction of a sub-frame by passing through the inner space of a housing block (12) combined with the sub-frame (10) and comprises a rack bar unit (3) including a bearing (3c) successively located inside the housing block (12), a ball screw nut (3b), and rack bar pulley (3d); a motor (2a) combined with a housing block (12) outside the housing block (12); a bolt fastened motor (2a); and a motor unit (2) including a belt (2c) connected to the rack bar pulley (3d) wrapped in the motor pulley (2b) of the motor (2a) located inside the housing block (12). The rack-motor driven power steering system has a characteristic in which the strength and hardness for an external force are improved by reducing the amount of components and by combining the system with the sub-frame (10). [Reference numerals] (AA) Steering column

Description

Rack Assist Electric Steering System and Assembling Method {Rack-Motor Driven Power Steering System and Assembling Method

The present invention relates to a rack assist electric steering apparatus, and in particular, an integral housing in which both a motor, a belt, a bearing, and a rack bar are assembled is integrally formed using a subframe, thereby reducing the number of parts and increasing the strength and rigidity using the integrated structure. A rack assist electric steering device is achieved and a method of assembly thereof.

In general, MDPS (Motor Driven Power Steering System), which is an electric steering device, is a method of assisting steering power by using motor power without using hydraulic pressure.

To this end, MDPS has a motor that generates power under ECU control, and a reducer consisting of a worm shaft that is rotated through the motor and a worm wheel that is engaged with it, assists steering power with motor power. )

On the other hand, R-MDPS (Rack-Motor Driven Power Steering System), which is a rack assist electric steering device, transfers the drive torque to the belt and transfers the drive torque to the belt to convert the nut into rotational motion. By consisting of the follower to implement, there is a somewhat different from the configuration of the MDPS and the steering capacity is also a greater difference.

Therefore, unlike the configuration of the MDPS, R-MDPS inevitably has a complicated configuration due to the motor and rack bar and the pulley, belt and ball nut connecting them.

As described above, the complicated construction of the R-MDPS results in an increase in manufacturing cost and an operation noise and loss of power transmission due to assembly tolerances between parts, and in particular, productivity is inevitably reduced due to more assembly processes.

Domestic Patent Publication 10-2011-0114898 (October 20, 2011)

The patent document is an example of a technology that simplifies a complicated configuration by a rack-motor driven power steering system (R-MDPS), a rack assist electric steering device, due to a pulley, a belt, a ball nut, and the like connected between the motor and the rack bar. Indicates.

To this end, the patent document consists of a nut-pulley member formed integrally with a ball nut portion and a belt pulley portion wound with a rack bar, coupled with a plurality of bearings for rotation of the nut-pulley member and fixedly coupled to the housing It consists of a guide flange member.

Through this, the patent document has a complicated configuration due to the nut and pulley member, the bearing and the guide flange member because of the pulley, belt and ball nut connecting the motor and the rack bar, and the like between them, and the cost reduction by simplifying the configuration In addition to reducing weight and shortening the assembly process, it also minimizes operating noise and power transmission losses.

However, the R-MDPS is combined with each other through a plurality of bolting operations and subframes made of separate components after each component is assembled, the overall configuration of the R-MDPS should be considered the structure and shape of the subframe.

Considering this aspect, the rack housing and the motor reducer housing of the R-MDPS is inevitably bolted to the setting position of the subframe in the state of being integrated by bolting fastening.

As described above, the R-MDPS and sub-frames are separately manufactured and bolted to each other, so that the assembly process is applied. There is no choice but to be poor.

 In particular, in the fastening structure of R-MDPS and subframe, the rack housing, motor reducer housing and subframe act as a structure to receive external force (lateral force) introduced through the lower arm and knuckle. none.

Therefore, in the fastening structure of the R-MDPS and the subframe, it is more preferable to integrate the rack housing, the motor reducer housing and the subframe with each other to reinforce the rigidity and the strength in terms of external force (lateral force).

However, in the fastening structure of the R-MDPS and the subframe, it is difficult to integrate the rack housing, the motor reducer housing, and the subframe with each other by focusing on the stiffness and strength of the external force (lateral force).

For example, even if the R-MDPS and the subframe are integrated, the basic shape of the R-MDPS and the subframe must be maintained, and in particular, the coupling structure of the bearing and the motor reducer housing is to be considered. Inevitably, the separation between the pinion housing side and the motor reducer housing side of the subframe is inevitably required.

The separation structure as described above requires bolting fastening to reduce the assembly process, and in particular, the unification intended for increasing rigidity and strength against external force (lateral force) cannot be achieved.

Accordingly, the present invention in view of the above point is that the integral housing, in which both the motor, the belt, the bearing, and the rack bar are assembled, is integrally formed using a subframe, so that the number of parts is reduced and in particular, the external structure (lateral force) is integrated into the integrated structure. It is an object of the present invention to provide a rack assist electric steering apparatus and a method for assembling thereof, which greatly increase in strength and rigidity.

Rack assist electric steering apparatus of the present invention for achieving the above object is a rack bar arranged in the longitudinal direction of the subframe through the inner space of the housing block integrally formed in the subframe, coupled with the rack bar and the housing A rack bar unit comprising a bearing, a ball screw nut, and a rack bar pulley sequentially positioned in an inner space of the block; A motor unit comprising a motor connected to the housing block and bolted to the outside of the housing block, and a belt wound around the motor pulley of the motor positioned as an inner space of the housing block and connected to the rack bar pulley; Is included.

The housing block may include a rack bar housing in which an inner space through which the rack bar penetrates forms a through hole, a rack bar extending housing integrally formed from the rack bar housing, and another through hole formed therein, and the rack bar extending from the position where the rack bar extending housing starts. It is formed integrally with the housing and consists of a motor housing in which the motor pulley and the belt are accommodated.

The housing cover is coupled to the opening of the through hole of the rack bar housing to block the inflow of foreign matter.

The motor housing communicates with a belt position hole, which is a space in which the motor pulley and the belt are accommodated, a motor position hole into which the motor pulley of the motor is coupled, and communicates with the belt position hole on the opposite side of the motor position hole. The adjustment hole for adjusting the belt from the outside is formed.

The belt cover is coupled to the opening of the adjustment hole to block the inflow of foreign matter.

A left tie rod fastened to the left and right knuckles of the left wheel and a right tie rod fastened to the knuckle of the right wheel are respectively connected to the left and right sides of the rack bar, and the pinion for transmitting the steering wheel operation force from the steering column is engaged with the rack gear of the rack bar. do.

In addition, the rack assist electric steering apparatus assembly method of the present invention for achieving the above object is press-fitting the bearing into the inner circumferential surface of the through-hole of the rack bag housing integrally formed in the sub-frame, the ball screw nut and the rack bar pulley After sequentially combining, the rack bar unit is assembled by combining the rack bars toward the through-holes of the rack bar extension housings connected to the rack bar housings; A belt is inserted through the through hole of the rack bar housing, and the belt is hooked to the rack bar pulley to position the belt position hole of the motor housing in communication with the through hole of the rack bar housing; The belt is hooked to a motor pulley inserted into a motor position hole communicating with a belt position hole of the motor housing, the motor is connected to a belt position hole of the motor housing after the motor pulley is fastened to the motor housing with a bolt. Adjusting the coupling between the belt and the motor pulley using the belt position hole, and then completely tightening the bolt to assemble the motor unit; The housing cover is coupled to the opening of the through hole of the rack bar housing to block the inflow of foreign matter; Above the opening of the adjustment hole is characterized in that the belt cover is coupled to block the inflow of foreign matter.

The rack bar exposed to the outside of the sub-frame out of the through-hole of the rack bar extension housing is wrapped with a rack bar housing, and the left tie rod fastened to the knuckle of the right wheel and the left tie rod fastened to the left and right sides of the rack bar. The right tie rods are connected to each other, and the pinion for transmitting the steering wheel manipulation force from the steering column is engaged with the rack gear of the rack bar.

The present invention is an integrated housing formed in the subframe R-MDPS (Rack-Motor Driven Power Steering System) is fastened to the connection between the sub-frame and the R-MDPS receiving external force (lateral force) coming through the lower arm and knuckle There is an effect that the strength and rigidity for the greatly increased.

In addition, the present invention is provided with an integrated housing in the subframe so that the motor, belt, bearing and rack bar of the rack-motor driven power steering system (R-MDPS) can be assembled, thereby providing a connection structure between the subframe and the R-MDPS. It also has the effect of greatly reducing the number of parts.

In addition, the present invention does not require bolting fastening of the assembly structure of the rack-motor driven power steering system (R-MDPS) and the subframe, thereby significantly reducing the assembly process of the subframe and the R-MDPS.

1 is a block diagram of a rack assist electric steering apparatus according to the present invention, Figure 2 is a flow chart of the rack assist electric steering apparatus according to the invention is assembled using a subframe, Figure 3 is a rack assist electric steering according to the present invention Layout of devices and subframes.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which illustrate exemplary embodiments of the present invention. The present invention is not limited to these embodiments.

FIG. 1 shows a state in which a rack-motor driven power steering system (R-MDPS), which is a rack assist electric steering apparatus according to the present embodiment, is assembled using a subframe 10.

The R-MDPS (1) is a motor unit (2) generating power for steering assistance, a rack bar unit (3) to which the left tie rod (6) and the right tie rod (7) are connected, and a rack bar unit ( 3) a hollow tube-type rack housing (5) wrapped, and a pinion (9) for transmitting the steering wheel operating force from the steering column to the rack bar unit (3).

The motor unit 2 includes a motor 2a as a power source, a motor pulley 2b connected to a reducer of the motor 2a, and a belt 2c wound around the motor pulley 2b to transmit the rotational force of the motor 2a. It consists of.

The rack bar unit 3 supports a rack bar 3a meshed with the pinion 9, a ball screw nut 3b having a ball-screw structure for linearly moving the rack bar 3a, and a rack bar 3a. It consists of a bearing 3c and a rack bar pulley 3d connected by a belt 2c wound around the motor pulley 2b so as to transmit the rotational force of the motor 2a to the ball screw nut 3b.

The rack housing 5 receives the rack bar 3a, the left tie rod 6 is connected to the knuckle of the left wheel, and the right tie rod 7 is connected to the knuckle of the right wheel.

The subframe 10 forms an assembly position forming unit 11 formed at right and left lengths of the subframe 10 so that the rack housing 5 forming the R-MDPS 1 is positioned, and the R-MDPS 1. The motor unit 2 and the rack bar unit 3 is composed of a housing block 12 formed as one portion of the subframe 10.

The assembly position forming unit 11 is manufactured integrally with the subframe 10 in a recessed shape during the manufacture of the subframe 10, while the housing block 12 protrudes during the manufacture of the subframe 10. It is manufactured integrally with the subframe 10 in a shape.

The housing block 12 has a rack bar housing 13 in which a through hole 13a is formed, a rack bar extension housing 15 which is integrally connected to the rack bar housing 13 and in which another through hole 15a is formed, and a rack bar extension housing. It consists of a motor housing 16 formed integrally using the rack bar housing 13 at the position (15) starts.

A housing cover 30 is coupled to the rack bar housing 13, and a belt cover 20 is coupled to the motor housing 16.

Through-holes 13a and 15a, which are spaces through which the rack bar 3a penetrates, are formed in the rack bar housing 13 and the rack bar extension housing 15, respectively, and in the through holes 15a of the rack bar extension housing 15. While the rack bar 3a is located, the ball screw nut 3b, the bearing 3c, and the rack bar pulley 3d are positioned in the through hole 13a of the rack bar housing 13 together with the rack bar 3a.

The housing cover 30 is fitted into the through hole 13a of the rack bar housing 13 to block the inside of the through hole 13a of the rack bar housing 13 from the outside.

The motor housing 16 is connected to the belt position hole 16b and the belt position hole 16b, which are spaces in which the belt 2c wound on the motor pulley 2b and connected to the rack bar pulley 3d is located, thereby communicating with the motor 2a. ) Is formed a motor position hole (16a) forming a space to be coupled to, and an adjustment hole (16c) for communicating the belt position hole (16b) on the opposite side of the motor position hole (16a) to adjust the belt (2c) from the outside .

The belt cover 20 is fitted into the adjustment hole 16c of the motor housing 16 to block the inside of the belt position hole 16b of the motor housing 16 from the outside.

On the other hand, Figure 2 shows the order of assembling the R-MFPS with the subframe according to this embodiment.

2 (a) is an initial stage in which the rack bar unit 3 is assembled with the subframe 10, which uses the opening of the through hole 13a formed in the rack bar housing 13 and the bearing 3c and the ball screw. Combine the nut 3b and the rack bar pulley 3d sequentially, and then insert the rack bar 3a into the through hole 13a of the rack bar housing 13 and push it to the through hole 15a of the rack bar extension housing 15. Simply put it in and you're done.

At this time, the bearing (3c) is pressed into the through hole (13a) of the rack bar housing (13).

2 (b) is a step in which the rack bar unit 3 is assembled with the housing block 12 and then the belt 2c is assembled, which causes the belt 2c to pass through the hole 13a of the rack bar housing 13. It is completed by pushing into the rack bar pulley (3d), and then pulled out into the belt position hole (16b) of the motor housing (16).

2 (c) is a step in which the rack bar unit 3 and the belt 2c are assembled with the housing block 12 and then the motor unit 2 is assembled, which is a motor pulley connected to the reducer of the motor 2a. It is completed by inserting (2b) into the motor position hole 16a and then tightening the bolt.

At this time, if necessary, by assembling the belt 2c from the outside using the adjustment hole 16c communicated with the belt position hole 16b, the assembling work of the belt 2c can be made simpler.

Then, after the belt 2c is completely wound on the motor pulley 2b and the rack bar pulley 3d, the motor 2a is completely fixed to the motor housing 16 by completely tightening the bolt to which the is fastened.

2 (d) is a step in which the rack bar unit 3, the belt 2c and the motor unit 2 are assembled with the housing block 12, and then the belt cover 20 and the housing cover 30 are assembled. This is completed through the simple operation of fitting the belt cover 20 into the adjustment hole 16c of the motor housing 16 and also fitting the housing cover 30 into the through hole 13a of the rack bar housing 13. .

2 (E) is a state in which the R-MDPS 1 is completely assembled with the subframe 10 using the housing block 12, in which the belt cover 20 is an adjustment hole of the motor housing 16. The housing cover 30 is fitted into the through hole 13a of the rack bar housing 13.

Therefore, the inner space of the housing block 12 is blocked by the belt cover 20 and the housing cover 30 can maintain the airtight to prevent foreign matter from penetrating into the interior.

3 (a) and 3 (b) show the layout of the R-MDPS 1 and the subframe 10 according to the present embodiment.

When the R-MDPS 1 is assembled to the subframe 10 as shown, the motor unit 2 is coupled to the housing block 12 of the subframe 10 and positioned to one side, and the pinion 9 is Located opposite the motor unit 2, the rack bar unit 3 is covered by a rack bar housing 5 arranged in the longitudinal direction of the subframe 10, and with the left tie rod 6 connected to the knuckle of the left wheel. The right tie rod 7 connected to the knuckle of the right wheel is respectively covered by a boot, and in particular, the housing block 12 is blocked from the outside by using the belt cover 20 and the housing cover 30.

As described above, the rack assist electric steering apparatus according to the present embodiment is coupled to the rack bars 3a arranged in the longitudinal direction of the subframe through the inner space of the housing block 12 integrally formed in the subframe 10. A rack bar unit (3) comprising a bearing (3c), a ball screw nut (3b), and a rack bar pulley (3d) sequentially positioned in an inner space of the housing block (12); The rack bar pulley (3d) is wound around the motor (2a) bolted to the housing block (12) outside the housing block (12) and the motor pulley (2b) of the motor (2a) located in the interior space of the housing block (12). By including the motor unit (2) consisting of a belt (2c) connected to the, it is possible to greatly increase the strength and stiffness of the external force (lateral force) as well as reducing the number of parts in an integrated structure with the subframe (10).

1: R-MDPS (Rack-Motor Driven Power Steering System)
2: motor unit 2a: motor
2b: motor pulley 2: belt
3: rack bar unit 3a: rack bar
3b: Ball screw nut 3c: Bearing
3d: rack bar pulley 5: rack housing
6: left tie rod 7: right tie rod
9: pinion 10: subframe
11: assembly position forming unit 12: housing block
13: rack bar housing 13a, 15a: through hole
15: rack bar extension housing 16: motor housing
16a: Motor position hole 16b: Belt position hole
16c: adjusting hole
20: belt cover 30: housing cover

Claims (8)

Rack bars arranged in the longitudinal direction of the subframe through the inner space of the housing block integrally formed in the subframe, bearings, ball screw nuts and rack bar pulleys are coupled to the rack bar and sequentially located in the inner space of the housing block. Rack bar unit consisting of;
A motor unit comprising a motor connected to the housing block and bolted to the outside of the housing block, and a belt wound around the motor pulley of the motor positioned as an inner space of the housing block and connected to the rack bar pulley;
Rack assist electric steering, characterized in that included.
The rack bar housing of claim 1, wherein the inner space through which the rack bar penetrates is formed in a rack bar housing, a rack bar extending housing integrally connected to the rack bar housing, and another through hole is formed, and the rack bar extending housing starts. Rack assist housing is formed integrally by using the rack bar housing in the position is characterized in that the motor assist pulley and the motor housing that is accommodated in the belt housing.
The rack assist electric steering apparatus according to claim 2, wherein the housing cover is coupled to the opening of the through hole of the rack bar housing to block the inflow of foreign substances.
3. The motor housing of claim 2, wherein the motor housing includes a motor position hole into which a motor pulley of the motor coupled to the outside is connected to a belt position hole, the space in which the motor pulley and the belt are accommodated, and opposite from the motor position hole. Rack assisted electric steering device is in communication with the belt position hole, characterized in that the adjustment hole for adjusting the belt from the outside is formed.
The rack assist electric steering apparatus according to claim 4, wherein a belt cover is coupled to the opening of the adjustment hole to block the inflow of foreign matter.
The left tie rod fastened to the left and right knuckles of the left wheel and the right tie rod fastened to the knuckle of the right wheel are respectively connected to the left and right sides of the rack bar, and the steering wheel operating force from the steering column is applied to the rack gear of the rack bar. Rack assist electric steering, characterized in that the pinion to be delivered is engaged.
The bearing is press-fitted into the inner circumferential surface of the through-hole of the rack bar housing integrally formed in the subframe, and then the ball screw nut and the rack bar pulley are sequentially joined to the bearing, and then the rack bar is coupled to the through hole of the rack bar extension housing connected to the rack bar housing. A rack bar unit is assembled;
A belt is inserted through the through hole of the rack bar housing, and the belt is hooked to the rack bar pulley to position the belt position hole of the motor housing in communication with the through hole of the rack bar housing;
The belt is hooked to a motor pulley inserted into a motor position hole communicating with a belt position hole of the motor housing, the motor is connected to a belt position hole of the motor housing after the motor pulley is fastened to the motor housing with a bolt. Adjusting the coupling between the belt and the motor pulley using the belt position hole, and then completely tightening the bolt to assemble the motor unit;
The housing cover is coupled to the opening of the through hole of the rack bar housing to block the inflow of foreign matter;
The assembly method of the rack assist electric steering device, characterized in that the belt cover is coupled to the opening of the adjustment hole to block the inflow of foreign matter.
The rack bar extending from the through-hole of the rack bar extension housing and exposed to the outside of the subframe is wrapped in a rack bar housing, and left tie rods and right wheels fastened to knuckles of a left wheel on both sides of the rack bar. The right tie rod fastened to the knuckle of each is connected, the rack assist rack assembly of the rack assist electric steering device, characterized in that the pinion for transmitting the steering wheel operating force from the steering column is engaged.

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