KR100738376B1 - Motor-joint of Electrical Power Steering System for in Use Vehicle - Google Patents

Abstract

The present invention relates to a motor joint of a motor-driven steering apparatus of an automobile.

The present invention provides a steering assist device for assisting a driver's steering force, comprising: a motor for assisting the driver's steering force; A drive shaft extending out of the motor; A gear device for decelerating and decelerating a rotation ratio of the motor to assist the driver's steering force; A driven shaft installed on a rotation center line of the drive shaft and transmitting a rotational force of the drive shaft to the gear device; And a motor joint installed between the driven shaft and the driving shaft to transmit a rotational force from the driving shaft to the driven shaft, wherein the motor joint protrudes radially from an outer circumferential surface of the driven shaft. An inner rotor having one or more protrusions that rotate together; An outer rotor having an inner circumferential surface surrounding the inner rotor and fixed to the drive shaft to rotate together with the drive shaft; And an elastic body configured between the outer rotor and the inner rotor and being in close contact with the protrusion and the inner circumferential surface of the outer rotor, the elastic body absorbing vibration and noise generated by the driving motor. Provide auxiliary devices.

According to the present invention, by inserting an elastic body between the inner rotor and the outer rotor and increasing the number of protrusions of the inner rotor or increasing the length in the radial direction of the rotational force that can be transmitted by the motor joint connecting the drive shaft and the worm shaft of the drive motor Not only can increase the range, but also has the effect of precisely transmitting the rotation of the drive shaft.

Joint, coupling, motor, steering, rotor, vibration

Description

Motor-joint of Electrical Power Steering System for in Use Vehicle

1 is a partial schematic view of a conventional steering shaft motor-driven steering apparatus;

2 is a partial cross-sectional view of a conventional steering shaft motor-driven steering apparatus;

3A is an exploded perspective view of a motor joint constituting a conventional steering shaft motor driven steering apparatus;

Figure 3b is an assembled cross-sectional view of the motor joint constituting the conventional steering shaft motor drive steering device,

4A is an exploded perspective view of a motor joint constituting a steering shaft motor driven steering device according to a first embodiment of the present invention;

4B is a cross-sectional view of a motor joint constituting a steering shaft motor driven steering device according to a first embodiment of the present invention;

4C is an exploded perspective view of a motor joint constituting a steering shaft motor driven steering device according to a second embodiment of the present invention;

4D is an exploded perspective view of a motor joint constituting a steering shaft motor driven steering apparatus according to a third embodiment of the present invention;

5 is an explanatory diagram for increasing the precision of the motor joint constituting the steering shaft motor-driven steering apparatus according to the embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

100: steering wheel 110: upper steering shaft

111: lower steering shaft 130: torsion bar

131: displacement sensor 132: first displacement gear

133: second displacement gear 140: worm gear

150: worm shaft 151: worm shaft gear

160: pinion 170: rack bar

180: electronic control unit 190: drive motor

191: drive shaft 200: outer rotor

210: elastic body 220: inner rotor

250: first bearing 251: second bearing

252: compression spring 253: compression screw

254: clearance 270: gear housing

310: straight portion 320: opposite straight portion

420: inner rotor 421: protrusion

430: elastomer 440: outer rotor

510: reference line 520: first error line

525: second error line 551: first reference point

552: second reference point 561: first contact point

562: second contact

  A: 1st circle B: 2nd circle

  x: 1st rotation angle y: 2nd rotation angle

The present invention relates to a motor joint of a motor-driven steering apparatus of an automobile. More specifically, in a motor-driven steering apparatus of an automobile, the joint connecting the drive shaft and the worm shaft of the drive motor increases the range of rotational force that can be transmitted, facilitates the adjustment of the transferable torque, and also rotates the rotational force of the drive shaft. The present invention relates to a motor joint of a motor-driven steering device of a vehicle that transmits precisely without any difference.

Various devices are installed in the car for improving the safety of the car and for the convenience of the driver. Among them, the steering device allows the driver to turn the steering wheel to freely change the direction of travel of the car. It is a device that assists the driver to advance the car in the desired direction by changing the rotation center arbitrarily.

In this steering system, a power steering system is added to relieve the driver's power. The power steering system uses hydraulic pressure to support steering power by operating a hydraulic pump using engine power. There is a motorized steering device using a driven steering device and an electric motor.

The hydraulically-driven steering system 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 driving unit such as a cylinder configured on the rack bar or the steering shaft to assist the driver's steering force.

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

The motor-driven steering device is connected to the drive shaft and the driven shaft of the motor, in which a flexible joint is used a lot to prevent the transmission of vibration between the drive shaft and the driven shaft.

The rack-and-pinion type steering system has a structure in which the steering wheel responds directly to the movement of the steering wheel because the movement of the pinion gear directly connected to the steering shaft is directly transmitted to the rack. Are widely used in front wheel drive cars.

1 is a partial schematic view of a conventional steering shaft motor-driven steering apparatus.

As shown in the figure, the steering shaft motor driving steering apparatus includes a steering wheel 100, an upper steering shaft 110, a torsion bar 130, a lower steering shaft 111, a pinion 160, a rack bar 170, and a first displacement. The gear 132, the second displacement gear 133, the worm shaft 150, the worm gear 140, the drive motor 190, the displacement sensor 131, and the electronic control unit 180 are configured to be included.

One end of the upper steering shaft 110 is connected to the rotation center of the steering wheel 100 and the other end is connected to the torsion bar 130. In addition, one end of the lower steering shaft 111 is connected to the torsion bar 130, the other end is connected to the pinion 160, and eventually, the rotational movement of the steering wheel 100 causes the rotational movement of the pinion 160 and pinion ( The rotation of 160 is converted to the linear motion of the rack bar 170 to steer the wheels.

In order to move the rack bar 170, more than a predetermined rotational force (torque) is to be transmitted to the pinion 160, the power assist device is installed to assist the rotational force applied by the driver to the steering wheel (100). As illustrated, a worm gear 140 is formed on the outer circumferential surface of the lower steering shaft 111, and the worm shaft 150 is engaged with the worm gear 140, and the driving motor 190 is connected to the worm shaft 150. It is. Therefore, as the drive motor 190 rotates, the worm shaft 150 rotates, and as the worm gear 140 rotates, the lower steering shaft 111 rotates, thereby assisting the driver's steering force.

The first displacement gear 132 is connected to the upper steering shaft 110, the second displacement gear 133 is connected to the lower steering shaft 111, the first displacement gear 132 and the second displacement gear 133 ) Are facing each other as shown. Since the upper steering shaft 110 and the lower steering shaft 111 are connected by the torsion bar 130, when the torsion bar 130 is twisted, between the first displacement gear 132 and the second displacement gear 133. Relative positions change with each other. The displacement sensor 131 is installed to detect a change in the relative position of the first displacement gear 132 and the second displacement difference 133 to generate a sensor signal, and the displacement sensor 131 detects the sensor signal thus detected. It also functions to transmit to the electronic control unit 180. The electronic control unit 180 analyzes the sensor signal received from the displacement sensor 131 to determine the degree of torsion of the torsion bar 130 to drive or stop the driving motor 190.

2 is a partial cross-sectional view of a conventional steering shaft motor-driven steering apparatus.

As illustrated, the steering shaft motor driving steering apparatus includes a driving motor 190, a driving shaft 191, an inner rotor 220, an outer rotor 200, an elastic body 210, a first bearing 250, and a worm shaft 150. ), A worm shaft gear 151, a second bearing 251, a compression screw 253, a compression spring 252, a gap 254, and a gear housing 270.

As shown, the drive motor 190 has a drive shaft 191 extending to the outside of the drive motor housing, the outer rotor 200 is interlocked with one side is connected to the drive shaft in the hollow inside.

The second bearing 251 and the first bearing 250 fix the worm shaft gear 151 to the worm gear 140 side installed on the lower steering shaft 111. The compression spring 252 holds the worm shaft gear 151 in the direction of the worm gear 140 by tightening the compression screw 253 and is configured in the second bearing 251. Therefore, when the compression screw 253 is tightened, the compression screw 253 moves in the direction of the gap 254, thereby causing the compression spring 252 to contract, and consequently, the worm shaft gear 151 is wormed by the compression force of the compression spring 252. To be firmly bite with the gear 140.

The worm shaft 150 has an inner rotor 220, and the inner rotor 220 has a structure in which one side is inserted into the outer rotor 200 connected to the driving shaft 191.

3A is an exploded perspective view of a motor joint constituting a conventional steering shaft motor driven steering apparatus.

As illustrated, the motor joint constituting the steering shaft motor-driven steering apparatus includes an outer rotor 200, an elastic body 210, and an inner rotor 220, and the outer rotor 200 is the inner rotor 220. It has a structure capable of interpolating and has an elastic body is provided between the inner rotor 220 and the outer rotor 200. In addition, a part of the outer circumferential surface of the inner rotor 220 is scraped off to form a straight portion 310, and the outer rotor 200 forms an opposite straight portion 320 that meshes with the straight portion 310. In general, the straight portion 310 has two or more, and likewise, the opposite straight portion 320 has two or more.

Figure 3b is an assembled cross-sectional view of the motor joint constituting the conventional steering shaft motor-driven steering apparatus.

In order for the outer rotor 200 to transmit the rotational force to the inner rotor 220, a straight portion 310 is formed in the inner rotor 220 and an opposite straight portion 320 is installed in the outer rotor 200. The part 310 and the opposite straight part 320 mesh with each other to prevent rotation slip when the rotational force of the outer rotor 200 is transmitted to the inner rotor 220.

The elastic body 210 installed between the inner circumferential surface of the outer rotor 200 and the outer circumferential surface of the inner rotor 220 prevents direct collision between the outer rotor 200 and the inner rotor 220 to prevent vibration and noise during rotation transmission. Not only attenuates and reduces, but also functions to absorb relative motion in the longitudinal direction of the drive shaft 191 and the worm shaft 150, and the longitudinal deformation occurring in the longitudinal direction and a minute angle change between the worm shaft 150 and the drive shaft 191. It also functions to absorb.

As described above, the structures of the outer rotor 200 and the inner rotor 220 used in the conventional motor-driven steering apparatus are formed by cutting the outer circumferential surface of the inner rotor 220 and the outer rotor 200. The rotational force is transmitted from the outer rotor 200 to the inner rotor 220 by the opposite straight portions 320 formed on the outer circumferential surface of the c), that is, the straight portions 310 and the opposite straight portions 320 engaged with each other.

Since the straight portion 310 is made by shaving the outer circumferential surface of the worm shaft 150, the distance from the rotation center of the inner rotor 220 to the straight portion 310 is smaller than the outer diameter of the inner rotor 220. Therefore, such a structure not only has a limit of the rotational force that can be transmitted in transmitting the rotational force of the drive shaft 191, but also causes a large rotation angle error between the rotation of the drive shaft 191 and the rotation of the worm shaft 150. There is a problem of impairing steering precision.

In order to solve the above problems, the present invention, in the motor-driven steering device of the vehicle, not only increases the range of rotational force that can be transmitted by the joint connecting the drive shaft and the worm shaft of the drive motor, but also facilitates the adjustment of the transmittable torque. It is also an object of the present invention to provide a motor joint of a steering shaft motor-driven steering apparatus which accurately transmits the rotational force of the drive shaft without any difference in the rotation angle.

In order to achieve the above object, the present invention provides a steering assistance device for assisting a driver's steering force, comprising: a motor for assisting the driver's steering force; A drive shaft extending out of the motor; A gear device for decelerating and decelerating a rotation ratio of the motor to assist the driver's steering force; A driven shaft installed on a rotation center line of the drive shaft and transmitting a rotational force of the drive shaft to the gear device; And a motor joint installed between the driven shaft and the drive shaft to transmit rotational force from the drive shaft to the driven shaft, wherein the motor joint is configured to protrude in a radial direction from an outer circumferential surface of the driven shaft. An inner rotor having one or more protrusions that rotate together; An outer rotor having an inner circumferential surface surrounding the inner rotor and fixed to the drive shaft to rotate together with the drive shaft; And an elastic body configured between the outer rotor and the inner rotor and being in close contact with the protrusion and the inner circumferential surface of the outer rotor, the elastic body absorbing vibration and noise generated by the driving motor. Provide auxiliary devices.

Hereinafter, exemplary 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 addition, 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.

Figure 4a is an exploded perspective view of the motor joint constituting the steering shaft motor drive steering apparatus according to the first embodiment of the present invention.

As shown, the motor joint includes an outer rotor 440, an inner rotor 420, a protrusion 421, and an elastic body 430.

The inner rotor 420 is configured by forming four protrusions 421 on the outer circumferential surface of the worm shaft 150, and the outer rotor 440 is fixed to the driving shaft 191 extending to the outside of the driving motor 190. The inner rotor 420 is formed to have a structure, and an elastic body 430 is provided between the inner rotor 420 and the outer rotor 440.

The main function of the elastic body 430, the drive shaft 191 and the worm shaft 150 and the function to reduce the vibration and noise that can be caused by directly hit between the inner peripheral surface of the outer rotor 440 and the outer peripheral surface of the inner rotor 420 It includes the function of absorbing the relative motion in the longitudinal direction of the absorption and the longitudinal deformation between the worm shaft and the drive shaft and the function of absorbing minute angular changes between the worm shaft 150 and the drive shaft 191. In addition, even if the rotation center of the worm shaft 150 and the rotation center line of the driving shaft 191 do not coincide, the rotational force is smoothly transmitted from the driving shaft 191 to the worm shaft 150.

The elastic body 430 is inserted between the protrusion 421 and the inner circumferential surface of the outer rotor 440, or after overmolding the elastic body 430 to the protrusion 421, the outer rotor 420 including the elastic body 430 is outside. It may be inserted into the rotor 440. In addition, after the elastic body 430 is overmolded on the inner surface of the outer rotor 440, the inner rotor 420 may be inserted into the inner surface.

4B is a cross-sectional view of a motor joint constituting a steering shaft motor-driven steering apparatus according to the first embodiment of the present invention.

As shown, the motor joint includes an outer rotor 440, an inner rotor 420, a protrusion 421, and an elastic body 430. When the driving motor 190 rotates, the outer rotor 440 rotates. As a result, the inner rotor 420 also rotates, and an elastic body 430 formed between the inner rotor 420 and the outer rotor 440 is configured between the outer rotor 440 and the inner rotor 420 to vibrate. Attenuates excessive noise and compensates for shaft alignment errors while transmitting rotational force of the driving motor 190. In addition, by adjusting the number and length of the protrusions 421, the range of torque that can be transmitted, that is, rotational force, is increased, and steering precision can be improved.

If the gap gap between the protrusion 421 and the inner circumferential surface of the outer rotor 440 is adjusted, the thickness of the elastic body 430 may be different. If the elastic body 430 is thick, vibration and noise will be smoothly absorbed. When the thickness of the elastic body 430 is thin, more precise steering operation is possible.

Meanwhile, the protrusion 432 may be formed on the elastic body 430 to compensate for the clearance between the inner circumferential surface of the elastic body 430 and the outer rotor 440 or between the outer circumferential surface of the elastic body 430 and the inner rotor 420.

Figure 4c is an exploded perspective view of the motor joint constituting the steering shaft motor-driven steering apparatus according to the second embodiment of the present invention.

As shown, the motor joint includes an outer rotor 440, an inner rotor 420, a protrusion 421, and an elastic body 430.

The inner rotor 420 is configured by forming one protrusion 421 on the outer circumferential surface of the worm shaft 150, and the outer rotor 440 is fixed to the driving shaft 191 extending to the outside of the driving motor 190. It is formed in a structure surrounding the rotor 420, the elastic body 430 is configured between the inner rotor 420 and the outer rotor 440.

Figure 4d is an exploded perspective view of the motor joint constituting the steering shaft motor-driven steering apparatus according to the third embodiment of the present invention.

The steering shaft motor-driven steering apparatus according to the third embodiment of the present invention is formed in a structure in which the outer rotor 440 surrounds the inner rotor 420 including two protrusions 421 included on an outer circumferential surface thereof. An elastic body 430 is configured between the 420 and the outer rotor 440. Here, the two protrusions 421 are formed to face each other at an angle of 180 degrees on the outer circumferential surface of the worm shaft 150, and the inner rotor 420 is inserted into the inner circumferential surface of the outer rotor 440.

5 is an explanatory diagram for increasing the precision of the motor joint constituting the steering shaft motor-driven steering apparatus according to the embodiment of the present invention.

As shown in FIG. 5, the first circle A, the second circle B, the reference line 510, the first error line 520, the second error line 525, the first reference point 551, and the first circle A And a second reference point 552, a first contact 561, a second contact 562, a first rotation angle x and a second rotation angle y.

The first circle A has a radius r, the second circle B has a radius 2r and these two circles are concentric circles. The reference line 510 is drawn from the center of each circle at 12 o'clock, and the intersection between the reference line 510 and the first circle A is called the first reference point 551, and the reference line 510 and the second circle ( When the intersection point with B) is referred to as the second reference point 552, two first and second error lines 520 and 525 having the same length are drawn at the first reference point 551 and the second reference point 552, respectively. The point where each of the first and second error lines 520 and 525 and the first circle A meet is called a first contact point 561, and the point where the second circle B meets is called a second contact point 562. The first rotation angle x and the second rotation angle y are formed by drawing two lines toward each of the first contact point 561 and the second contact point 562 at the centrifuge.

Although the first and second error lines 520 and 525 of the first circle A and the second circle B have the same length, the first rotation angle x formed in the two circles A and B and The second rotation angle y shows a large difference close to about twice. The reason can be explained by the difference in the diameter of the two circles (A, B). Furthermore, if the diameter of the second circle B is larger, the second rotation angle y will be further reduced.

If the above-described principle is applied to the present invention, even if a rotational tolerance occurs between the inner rotor 420 and the outer rotor 440, the difference in the rotation angle can be reduced. That is, by increasing the length of the protrusion 421 formed in the radial direction on the outer circumferential surface of the inner rotor 420 and configuring the elastic body 430 as far as possible from the center of rotation can reduce the difference in the rotation angle.

In conclusion, by adjusting the length of the protrusion 421 and the configuration position of the elastic body 430, not only the difference in the rotation angle can be reduced but also the transmittable rotational force can be increased.

When the rotational torque of the drive motor 190 is small, the length of the protrusion 421 is configured to be short or the number is small. When the rotational torque of the drive motor 190 is large, the length of the protrusion 421 is lengthened or the number is reduced. In order to reduce the difference in the rotation angle between the drive motor 190 and the worm shaft 150, the length of the protrusion 421 may be increased, and then the elastic body 430 may be installed at a part far from the rotation center. .

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, the motor joint connecting the drive shaft and the worm shaft of the drive motor by inserting an elastic body between the inner rotor and the outer rotor and increasing the number of protrusions of the inner rotor or increasing the length in the radial direction. Not only can increase the range of torque that can be transmitted, but also has the effect of precisely transmitting the rotation of the drive shaft.

Claims (12)

A steering assistance device for assisting a driver's steering force, comprising: a motor for assisting the driver's steering force; A drive shaft extending out of the motor; A gear device for converting a rotation ratio of the motor to assist the driver's steering force; A driven shaft installed on a rotation center line of the drive shaft and transmitting a rotational force of the drive shaft to the gear device; And a motor joint installed between the driven shaft and the drive shaft to transmit rotational force from the drive shaft to the driven shaft. The motor joint, An inner rotor having one or more protrusions rotating together with the driven shaft in a radially projecting direction from an outer circumferential surface of the driven shaft; An outer rotor having an inner circumferential surface surrounding the inner rotor and fixed to the drive shaft to rotate together with the drive shaft; And An elastic body that is configured between the outer rotor and the inner rotor to absorb the vibration and noise generated by the drive motor Motor-driven steering assistance device comprising a. The method of claim 1, And two protruding portions facing each other at 180 degree intervals. delete The method of claim 1, Motor-driven steering assist device, characterized in that four projections are radially formed at intervals of 90 degrees. delete The method of claim 1, wherein the protrusion The drive shaft is formed in a radial direction with respect to the driven shaft and has a length longer from the rotation center of the driven shaft to the outer peripheral surface of the driven shaft than the length from the rotation center of the driven shaft to the drive shaft. Motor-driven steering assistance device, characterized in that for reducing the rotational error between the driven shaft. The method of claim 1, The motor-driven steering assist device, characterized in that the elastic body further comprises a projection in contact with the outer rotor in order to compensate for play between the elastic body and the outer rotor. delete delete The method of claim 1, And the elastic body is overmolded on the protrusion. The method of claim 1, And the elastic body is overmolded on the inner circumferential surface of the outer rotor. delete

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