KR102660407B1 - Rack Assist Type Electric Power Steering Apparatus - Google Patents

Abstract

The present invention relates to a rack-driven power-assisted steering device, and the present invention includes a bearing mounted on the outer peripheral surface of a ball nut to support rotation, a lock screw coupled between the outer ring of the bearing and a gear housing to support the bearing, a rack housing, and A rack-driven type that includes a seating portion that is seated along the mating surface in contact with the gear housing, and a packing plate that protrudes from the seating portion and is supported on the outer surface of the lock screw, and is provided with a support portion that supports the lock screw in the central axis direction. Power assisted steering is provided.

Description

Rack Assist Type Electric Power Steering Apparatus}

The present invention relates to a rack-driven power auxiliary steering device. More specifically, the present invention relates to a rack-driven power auxiliary steering device, and more specifically, when a rack bar is slid while a ball nut rotates, the lock is moved by axial and radial vibrations generated through the rack bar, ball nut, rack housing, etc. This relates to a rack-driven power-assisted steering device that can prevent screws from loosening, reduce vibration and noise transmitted through ball nuts and rack bars, and provide a comfortable steering feel to the driver.

As a power auxiliary steering device for automobiles, a hydraulic power steering device using hydraulic pressure from a hydraulic pump is generally used, but recently, an electric power steering device using a motor is gradually becoming more common.

A typical electric steering system includes a steering system that extends from the steering wheel to both wheels and an auxiliary power mechanism that supplies steering assistance power to the steering system.

The auxiliary power mechanism includes a torque sensor that detects the steering torque applied to the steering wheel by the driver and outputs an electrical signal proportional to the detected steering torque, and an electronic control unit (ECU) that generates a control signal based on the electrical signal transmitted from the torque sensor. : Electronic Control Unit), which includes a motor that generates steering auxiliary power based on control signals transmitted from the electronic control device, and a belt-type transmission device that transmits the auxiliary power generated by the motor to the rack bar through a belt.

Figure 1 is a partial cross-sectional view schematically showing a rack-driven power auxiliary steering device according to the prior art, and Figure 2 is a cross-sectional view schematically showing a part of a rack-driven power auxiliary steering device according to the prior art.

As shown in Figures 1 and 2, the rack-driven power auxiliary steering device according to the prior art includes a rack bar 140 that extends in the transverse direction of the car and has a rack gear on one side of the outer peripheral surface, and a pinion gear that engages the rack gear. A pinion shaft 110 provided, a ball nut 210 engaged with the outer screw groove 145 via a ball 220, and a belt-type transmission device 160 connecting the ball nut 210 and the motor shaft 155. ) and a motor 150.

The pinion shaft 110 is connected to the steering wheel through the steering shaft, and the rack bar 140, which has an outer screw groove 145 of a certain length formed on one side of the outer peripheral surface, is built into the rack housing 120.

The belt-type transmission device 160 is formed including a belt connecting the motor shaft 155 and the ball nut 210, and provides steering assistance power generated from the motor 150 in proportion to the steering torque applied to the steering wheel. It is transmitted to the rack bar 140 through the nut 210.

As shown in Figure 2, the rack-driven power auxiliary steering device according to the prior art includes a rack bar 140 having an outer screw groove 145 on the outer peripheral surface, and an intermediate path 215 through which the balls 220 circulate. A ball nut 210, a ball 220 that rolls while contacting the outer screw groove 145 and the middle path 215 of the rack bar, an end cap 230 attached to the end of the ball nut 210, etc. It consists of:

In this rack-driven power auxiliary steering device, the ball 220 moves the rack bar 140 by rolling while contacting the outer screw groove 145 of the rack bar 140 and the inner screw groove of the ball nut 210. It is made to slide.

However, in the case of this prior art, there was a problem in that noise and vibration were generated through the rack bar, ball nut, bearing, rack housing, etc. when the ball nut rotated and the rack bar was slid, and this noise and vibration was transmitted to other parts. There was a problem with the delivered and fastened parts coming loose.

In addition, there was a problem in that the noise and vibration transmitted in this way were transmitted to the driver along with the vibration and noise of other parts, deteriorating the driver's steering feel.

Accordingly, the present invention was developed against the above-described background, and in the rack-driven power auxiliary steering device of an automobile, when the ball nut rotates and the rack bar is slid, the axial direction and tilt generated through the rack bar, ball nut, rack housing, etc. The purpose is to prevent the lock screw from loosening due to directional vibration, reduce the transmission of vibration and noise through the ball nut and rack bar, and provide a comfortable steering feeling to the driver.

Additionally, the object of the present invention is not limited thereto, and other objects not mentioned may be clearly understood by those skilled in the art from the description below.

In order to achieve this purpose, the present invention includes a bearing mounted on the outer peripheral surface of a ball nut to support rotation, a lock screw coupled between the outer ring of the bearing and the gear housing to support the bearing, and a mating surface that contacts the rack housing and the gear housing. A rack-driven power assist steering device is provided, including a seating portion that is seated along the seating portion, a packing plate that protrudes from the seating portion and is supported on the outer surface of the lock screw, and is provided with a support portion that supports the lock screw in the central axis direction. .

According to the present invention, it is possible to prevent the lock screw from loosening due to axial and radial vibration generated through the rack bar, ball nut, rack housing, etc. when the ball nut rotates and slides the rack bar, and the ball nut It is possible to reduce the transmission of vibration and noise through the and rack bars, etc., and has the effect of providing a pleasant steering feeling to the driver.

1 is a partial cross-sectional view schematically showing a rack-driven power auxiliary steering device according to the prior art;
Figure 2 is a cross-sectional view schematically showing a part of a rack-driven power auxiliary steering device according to the prior art;
Figure 3 is an exploded perspective view showing a part of a rack-driven power auxiliary steering device according to an embodiment of the present invention;
Figure 4 is a perspective view showing a packing plate among the rack-driven power auxiliary steering device according to an embodiment of the present invention;
Figure 5 is a perspective view showing a state in which the packing plate is mounted on the gear housing of the rack-driven power auxiliary steering device according to an embodiment of the present invention;
Figure 6 is a cross-sectional view of Figure 5;
Figure 7 is a perspective view showing a modified embodiment of the packing plate in the rack-driven power auxiliary steering device according to an embodiment of the present invention;
Figure 8 is a perspective view showing the packing plate of Figure 7 mounted on the gear housing;
Figure 9 is a perspective view showing a part of a modified embodiment of the packing plate in the rack-driven power auxiliary steering device according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through illustrative drawings. When adding reference numerals to components in each drawing, it should be noted that identical components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present invention, if 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 will be omitted.

Additionally, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term. When a component is described as being “connected,” “coupled,” or “connected” to another component, that component may be directly connected or connected to that other component, but there is another component between each component. It will be understood that elements may be “connected,” “combined,” or “connected.”

Figure 3 is an exploded perspective view showing a part of a rack-driven power auxiliary steering device according to an embodiment of the present invention, Figure 4 is a perspective view showing a packing plate among the rack-driven power auxiliary steering device according to an embodiment of the present invention, Figure 5 is a perspective view showing a state in which the packing plate is mounted on the gear housing among the rack-driven power auxiliary steering devices according to an embodiment of the present invention, Figure 6 is a cross-sectional view of Figure 5, and Figure 7 is a rack-driven power assist steering device according to an embodiment of the present invention. A perspective view showing a modified embodiment of the packing plate among the power assist steering devices. Figure 8 is a perspective view showing the packing plate of Figure 7 mounted on the gear housing, and Figure 9 is a rack-driven power assist according to an embodiment of the present invention. This is a perspective view showing part of a modified embodiment of the packing plate among the steering devices.

As shown in these drawings, the rack-driven power auxiliary steering device according to the present invention includes a bearing 309 that is mounted on the outer peripheral surface of a ball nut 315 coupled to the rack bar 140 through a ball to support rotation, A lock screw (307) coupled between the outer ring of the bearing (309) and the gear housing (305) to support the bearing (309), and a mating surface (303a, 305a) in contact with the rack housing (303) and the gear housing (305). It is provided with a seating portion 322 that is seated along the seating portion 322, a support portion 325 that protrudes from the seating portion 322 and is supported on the outer surface of the lock screw 307 and supports the lock screw 307 in the central axis direction. Includes a packing plate 320.

This rack-driven power auxiliary steering device includes a driving means and a driven means. The driving means includes an electric motor controlled by an electronic control unit (ECU), a drive pulley fixed to the shaft 155 of the electric motor, and a drive belt. (335) etc.

In addition, the driven means is provided with a rack housing 303 surrounding the rack bar 140 and a ball nut 315 supporting the rack bar 140 inside the gear housing 305, and is provided separately on the outer peripheral surface of the ball nut 315. A molded or coupled driven pulley 310 is provided.

The driving pulley connected to the electric motor and the driven pulley 310 connected to the rack bar 140 are arranged parallel to each other, and a drive belt 335 is inserted into the driving pulley and driven pulley 310 to transfer the rotational force of the electric motor to a ball nut. It is transmitted to the rack bar 140 through 315, and the rack bar 140 is moved left and right by the operation of the ball nut 315 to generate a steering assistance force.

The ball nut 315 is coupled to the rack bar 140 through a ball and rotates to cause the rack bar 140 to slide on the inside of the rack housing 303 and the gear housing 305, and the outer peripheral surface of the ball nut 315 is A bearing 309 is installed to support the rotation of the ball nut 315.

A power transmission structure is provided on the inner peripheral surface of the ball nut 315 and the outer peripheral surface of the rack bar 140 to generate a steering assistance force by sliding the rack bar 140 in the axial direction. This power transmission structure is provided on the inner peripheral surface of the rack bar 140. It consists of an outer screw groove provided in a spiral shape with a hemispherical cross-section on the outer peripheral surface, a ball (not shown) inserted into the outer peripheral surface, and an inner screw groove provided in a spiral shape with a hemispherical cross-section on the inner peripheral surface of the ball nut 315 to correspond to the outer screw groove.

The ball nut 315 is a hollow tube with an inner screw groove formed on the inner circumferential surface, and driven pulleys 310 are installed in close contact with both sides of the outer circumferential surface. A bearing 309 is installed on one outer circumferential side of the ball nut 315, and this bearing At one end of the outer ring and the outer peripheral surface of (309), a lock screw (307) is screwed to the inner peripheral surface of the gear housing (305) and is fixed to support the bearing (309).

In addition, the packing plate 320 coupled to the mating surfaces 303a and 305b of the rack housing 303 and the gear housing 305 has at least one support portion 325 that supports the lock screw 307 in the central axis direction. The above is provided to prevent loosening of the lock screw 307 and dampen vibration and noise transmitted through the bearing 309.

The packing plate 320 has a seating portion 322 that is seated along the mating surfaces 303a and 305b in contact with the rack housing 303 and the gear housing 305, and a lock screw 307 that protrudes from the seating portion 322. ) is supported on the outer surface and is provided with a support portion 325 that supports the lock screw 307 in the central axis direction.

That is, the rack housing 303 and the gear housing 305 have a hollow part into which the driven pulley and the ball nut 315 are inserted and a hollow part into which the driving pulley and the motor are inserted are arranged on the same axis, and are packed in a shape to surround these hollow parts. A seating portion 322 of the plate 320 is formed.

In addition, the seating portion 322 is provided with an embossed portion 326 in which the central portion of the inner and outer ends protrudes convexly in the central axis direction and is elastically compressed when the rack housing 303 and the gear housing 305 are coupled. , the coupling surface of the rack housing 303 and the coupling surface of the gear housing 305 are coupled by a fastening member while elastically compressing the embossed portion 326.

In addition, the seating portion 322 is provided with a flange portion 321 extending from the outer end, and the flange portion 321 is connected to the fastening holes 303b and 305b formed in the rack housing 303 and the gear housing 305. A cylindrical intubation portion 323 to be inserted is provided so that the assembly position of the packing plate 320 can be accurately set.

This intubation portion 323 may be formed integrally with the flange portion 321 or may be manufactured separately and coupled to the flange portion 321.

When the intubation portion 323 is manufactured separately and coupled to the flange portion 321, the intubation portion 323 is formed in a cylindrical shape and has fastening holes 303b, 305b formed in the rack housing 303 and the gear housing 305. is inserted into

In addition, when the intubation part 323 is formed integrally with the flange part 321, it protrudes from the flange part 321 toward the rack housing 303, is inserted into the fastening hole 303b, and is connected to the gear in the flange part 321. It is formed in a shape that protrudes toward the housing 305 and is inserted into the fastening hole 305b, and the fastening member is connected to the intubation portion. The rack housing 303 and the gear housing 305 are coupled through (323).

Alternatively, when the intubation portion 323 is formed integrally with the flange portion 321, the first intubation portion 323a is bent to be inserted into the fastening hole 303b formed in the rack housing 303 in the flange portion 321. and a second intubation part 323b bent to the opposite side of the first intubation part 323a so as to be inserted into the fastening hole 305b formed in the gear housing 305.

That is, the central portion corresponding to the fastening holes 303b and 305b formed in the rack housing 303 and the gear housing 305 of the flange portion 321 is divided into two or more, and a portion of the divided flange portion is divided into the rack housing 303. ) is bent toward and inserted into the fastening hole (303b), and the rest is bent toward the gear housing 305 and inserted into the fastening hole (305b).

As an example, in Figure 9, the flange portion 321 is divided into four parts, and among the divided flange portions, the first intubation portion 323a is bent to one side and inserted into the rack housing 303, and the second intubation portion 323b is bent to one side. It may be bent to the opposite side and inserted into the gear housing 305, where the divided flange portions may be alternately bent to one side and the opposite side to alternately form first intubation portions 323a and second intubation portions 323b.

Figure 9 (a) is a perspective view of a portion of the flange portion 321, and Figure 9 (b) is a portion of the flange portion 321 showing the state before the flange portion 321 is divided into four pieces and bent. In the front view, the flange portion 321 is divided as shown in (b) of FIG. 9, and then each is bent to one side and the opposite side to form the first intubation portion 323a on the flange portion 321 as shown in (a) of FIG. 9. ) and the second intubation part 323b are formed, and the first intubation part 323a and the second intubation part 323b are inserted into the fastening holes 303b and 305b.

The support portion 325 that protrudes from the seating portion 322 extends radially inward from the inner end of the seating portion 322 to be located on the outer surface of the lock screw 307 and includes a first support portion 325a that protrudes. It is formed.

The first support portion 325a is provided with a second support portion 325b that is bent toward the central axis and is elastically compressed on the outer surface of the lock screw 307 when the rack housing 303 and the gear housing 305 are coupled.

As shown in FIG. 4, the second support portion 325b is formed extending from the first support portion 325a to both sides in the circumferential direction, and is convex or concave and bent in the direction of the central axis to form a coupling surface of the rack housing 303. (303a) and the coupling surface (305a) of the gear housing (305) are coupled while elastically compressing the second support portion (325b), thereby preventing rotational loosening of the lock screw (307).

That is, the second support portion 325b is bent on both sides in the circumferential direction with respect to the first support portion 325a, thereby preventing both clockwise and counterclockwise rotation of the lock screw 307.

In addition, as shown in FIG. 7, the first support portion 325a may be formed in several numbers spaced apart along the circumferential direction of the lock screw 307. In this case, the first support portion 325a has an end extending in the radial direction. A second support portion 325c is provided that is bent in the direction of the central axis and is elastically compressed on the outer surface of the lock screw 307 when the rack housing 303 and the gear housing 305 are coupled.

Here, the second support portion 325c is formed in a radial length from the inner end of the seating portion 322 to be different from the adjacent second support portion 325c. As shown in FIGS. 7 and 8, the second support portion ( 325c) may be formed so that short and long radial lengths from the inner end of the seating portion 322 are alternately arranged in the circumferential direction.

The second support portions 325b of different lengths respectively support the inner and outer sides of the lock screw 307, thereby preventing rotation of the inner and outer surfaces of the lock screw 307 when rotation of the lock screw 307 occurs. It is supported evenly to prevent rotational loosening.

The packing plate 320 is made of an elastic material such as metal, and in some cases, NR (Natural Rubber), BR (Polybutadiene Rubber), NBR (Nitrile Butadiene Rubber), CR (Chloroprene Rubber), and EPDM (Ethylene Propylene). It is made of materials such as Terpolymer), FPM (Fluoro Elastomer), SBR (Styrene Butadine Rubber), CSM (Chlorosulphonated Polyethylene), silicone, and urethane, and also plays a damping role by absorbing noise and vibration.

According to the present invention as described above, when the rack bar 140 is slid while the ball nut rotates, it is possible to prevent the lock screw from being loosened by vibration in the axial and radial directions generated through the rack bar, ball nut, rack housing, etc. This can reduce the transmission of vibration and noise through the ball nut and rack bar, and has the effect of providing a pleasant steering feel to the driver.

In the above, even though all the components constituting the embodiment of the present invention have been described as being combined or operated in combination, the present invention is not necessarily limited to this embodiment. That is, as long as it is within the scope of the purpose of the present invention, all of the components may be operated by selectively combining one or more of them.

In addition, terms such as “include,” “comprise,” or “have” as used above mean that the corresponding component may be included, unless specifically stated to the contrary, and thus do not exclude other components. Rather, it should be interpreted as being able to include other components. All terms, including technical or scientific terms, unless otherwise defined, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains. Commonly used terms, such as terms defined in a dictionary, should be interpreted as consistent with the meaning in the context of the related technology, and should not be interpreted in an idealized or overly formal sense unless explicitly defined in the present invention.

The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications and variations will be possible to those skilled in the art without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

140: Rack bar 303: Rack housing
305: gear housing 307: lock screw
309: bearing 310: driven pulley
320: Packing plate 321: Flange portion
323: intubation unit 325: support unit

Claims (13)

A bearing mounted on the outer peripheral surface of the ball nut to support rotation;
A lock screw coupled between the outer ring of the bearing and the gear housing to support the bearing;
Packing provided with a seating portion that is seated along the mating surface that contacts the rack housing and the gear housing, and a support portion that protrudes from the seating portion and is supported on the outer surface of the lock screw and supports the lock screw in the central axis direction. plate;
Includes,
The support portion is formed with a first support portion extending radially inward from the inner end of the seating portion and protruding so as to be located on the outer surface of the lock screw,
A rack-driven power assist steering device, characterized in that the first support part is provided with a second support part that is bent in the direction of the central axis and elastically compresses the outer surface of the lock screw when the rack housing and the gear housing are coupled. According to claim 1,
A rack-driven power assistance steering device, characterized in that the seating portion is provided with an embossed portion in which the central portion of the inner and outer ends protrudes convexly in the central axis direction and is elastically compressed when the rack housing and the gear housing are coupled. According to claim 2,
A rack-driven power assist steering device, characterized in that the seating portion is provided with a flange portion extending from an outer end. According to claim 3,
A rack-driven power assist steering device, characterized in that the flange portion is provided with a cylindrical tube portion inserted into a fastening hole formed in the rack housing and the gear housing. According to claim 4,
A rack-driven power assist steering device, characterized in that the flange portion and the tube portion are formed integrally. According to claim 3,
The flange part is provided with a first tube part bent to be inserted into a fastening hole formed in the rack housing, and a second tube part bent to the opposite side of the first tube part to be inserted into a fastening hole formed in the gear housing. A rack-driven power-assisted steering device. delete delete According to claim 1,
A rack-driven power assist steering device, wherein the second support portion extends from the first support portion to both sides in the circumferential direction and is bent. According to claim 1,
A rack-driven power auxiliary steering device, characterized in that the first support portion is formed in several numbers spaced apart along the circumferential direction of the lock screw. According to claim 10,
Rack driving, characterized in that the first support part is provided with a second support part at an end extending in the radial direction that is bent in the direction of the central axis and is elastically compressed on the outer surface of the lock screw when the rack housing and the gear housing are coupled. type power assisted steering. According to claim 11,
A rack-driven power assist steering device, wherein the second support portion has a radial length from the inner end of the seating portion that is formed differently from the adjacent second support portion. According to claim 12,
A rack-driven power auxiliary steering device, characterized in that the second support portion is formed with short and long radial lengths from the inner end of the seating portion alternately arranged in the circumferential direction.

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