KR101321315B1 - Tilt performance typed reduction gear device of motor driven power steering system in vehicle - Google Patents

Abstract

The present invention relates to a vehicle electric steering apparatus having a tilting behavior type reducer, comprising: a worm shaft bearing that wraps and supports a portion of a worm shaft (6) that forms a reducer (2) and is connected to a motor (5) side driven by an ECU (3). (12) As the portion has a tilting device 11 having an elastic body and in which an axial displacement can be generated, the movement of the displacement bearing 20 supporting the portion of the worm shaft 6 opposite the motor 5 The tilt movement device 11 allows the worm shaft 6 to be smoothly in contact with the axial diameter direction of the worm wheel 7 so that the worm shaft 6 may be absorbed along with the shock absorbed through the worm wheel 7. And the gears of the worm wheel (7) has a feature that can absorb the back lash (Back Lash) due to wear.

Description

Tilt performance typed reduction gear device of motor driven power steering system in vehicle

1 (a), (b) is a configuration diagram of a vehicle electric steering apparatus having a tilting behavior type reducer according to the present invention.

2 is a block diagram of a clearance adjustment device according to the present invention

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

1: Steering Column 2: Reducer

3: ECU 4: Rack Mechanism

5: motor 6: worm shaft

7: worm wheel 8: worm shaft housing

9: motor side connection housing

10: seating receiving groove 10a: inner insertion groove

10c: outer screw groove

11: Tilt moving device 12: Worm shaft bearing

13: snap ring 14: bush bearing

14a, 14c: inner and outer ring 14b: elastic body

15: screw plug 20: displacement bearing

The present invention relates to a vehicle electric steering apparatus, and more particularly to a vehicle electric steering apparatus having a tilting behavior type reducer.

Generally, a power steering device that generates a steering force of a vehicle is designed and operated to use hydraulic pressure in order to lighten the steering force of the steering wheel smoothly while allowing a quick steering.

Such a power steering device can be steered with a small force, can be selected regardless of the steering force of the steering gear ratio, and can be prevented from being transmitted to the handle by absorbing the impact from the unevenness of the road surface. have.

In addition, in recent years, the electronic control unit (ECU) drives the motor according to the driving conditions of the vehicle detected by the vehicle speed sensor and the steering torque sensor to provide a light and comfortable steering feeling at low speed, and a heavy steering feeling at high speed. The trend is to use an electric steering system that provides directional stability and provides optimum steering conditions to the driver by enabling rapid steering in emergency situations.

Such electric steering devices are usually electro-hydraulic power steering (EHPS) or motor driven power steering (MDPS), and the dual MDPS system, unlike the hydraulic system that forms the hydraulic pressure in the pump and assists the power, It is a structure that assists steering power with rotational force.Worm-Shaft, which is connected to a power generating motor, rotates the Worm Wheel, which is connected to Steering-Shaft, to assist steering power. assisted.

At this time, in the structure that is engaged between the gears to transmit the rotational force, wear occurs gradually between the contact portions of the rotating portion as the use progresses, and in particular, the axial play of the worm shaft is increased, the rattle noise ( Rattle Noise is inevitably caused. Therefore, a gap prevention means is used to press the worm shaft toward the worm wheel so as to eliminate the gap between the worm shaft and the worm wheel by using a rattle spring. Lose.

In addition, such an electric steering device is generally equipped with a tilt (Tilt) device, and after such a tilting (tilting) operation, the worm shaft and the worm wheel must be fully engaged with each other, of course, the normal operation is made.

However, gear wear occurs due to the passage of time between the worm shaft and the worm wheel, which are always engaged with each other according to the operation of the steering system.After the tilting operation, the gear between the worm shaft and the worm wheel is engaged even though the worm shaft is pressed using There is a phenomenon that does not maintain the correct bite.

Accordingly, by using the clearance of the bearing supporting the rotation of the worm shaft (Clearance) to absorb the wear of the gear teeth between the worm shaft and the worm wheel, but the clearance of the bearing also has a limitation in structure, there is a limit between the worm shaft and the worm wheel If the wear of the gear teeth exceeds the clearance of the bearings, the gears between the worm shaft and the worm wheel may not engage in the correct engagement and may generate vibration and noise.

When using self-aligning bearings with sufficient internal shock absorption in order to solve the limitations of the bearings themselves, the self-aligning bearings can absorb sufficiently even if the gears between the worm shaft and the worm wheel become large. In addition, the self-aligning bearing has a limit that can only increase the overall size as the play is formed internally.

In addition, when the vehicle travels on a rough road, a shock is transmitted to the worm shaft as a momentary shock is applied to the worm wheel, and such a shock typically causes rattle noise through the worm shaft and the worm wheel part. In order to prevent the shock absorber using a number of parts to absorb the shock is installed, this results in an increase in the overall number of parts, which has a limit that can not only increase the size but also the overall size.

In particular, in the case of blocking the above vibration and rattle noise by using the play of the bearing, that is, in a structure that allows the bearing about 0.5 ° to be displaced, the sound of hitting the ball between the inner and outer rings of the bearing Due to this, there is a disadvantage of damaging the surface of the bearing race, and furthermore, there is a limit that may hinder the basic role of the bearing supporting the load of the shaft.

Accordingly, the present invention has been made in view of the above-described aspects, and by attaching and inserting an elastic body capable of causing a certain portion of elastic displacement in the outer ring of the bearing supporting the worm shaft, the axial direction and the axial diameter direction and the axial direction centering the bearing Its purpose is to absorb the backlash of the reducer by absorbing the backlash of the reducer while absorbing the impact of the vehicle or the externally impacted joints while eliminating the joints caused by the misalignment of the bearing. have.

In order to achieve the above object, the present invention provides a motorized steering apparatus for a vehicle, comprising: a speed reducer configured to transmit a steering wheel steering force of a driver to generate a rotational force for operating a steering column for operating a rack mechanism for operating a tie rod;

An ECU for receiving vehicle driving information together with a sensor signal for detecting a driver's steering intention and supplying a control current;

Displacement bearings that support the worm shaft parts to enable the reduction gear center line behavior of the worm shaft engaged with the worm wheel combined with the steering column, and worm shaft bearing parts that support the worm shaft parts connected to the motor on the opposite side of the displacement bearing. A tilt movement device having an elastic body to surround the worm shaft bearing so as to be moved in the axial direction of the shaft;

.

The tilt movement device includes a seat receiving groove formed by a motor side connection housing of a worm shaft housing for receiving a worm shaft rotating at a high speed through a motor, a worm shaft bearing surrounding the worm shaft portion, and a misalignment of the worm shaft bearing. The bush bearing 14 is screwed into the bush bearing and the outer screw groove having a diameter larger than the diameter of the inner insertion groove, which absorbs the shock transmitted along with the axial behavior according to the axial and axial loads. ) Consists of a screw plug to fix the position.

In addition, the bush bearing is provided between a displaceable inner ring surrounding the worm shaft bearing, an outer ring fitted in close contact with the inner insertion groove of the seating receiving groove, and an elastic body provided between the inner ring and the outer ring to absorb shock and impart axial behavior. Wherein the bush bearing is formed through the right clearance formed into the inner insertion groove of the seat receiving groove, and the left clearance formed toward the inner diameter of the screw plug, the inner ring forming the bush bearing is characterized in that the axial displacement is constrained. It is done.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 (a) is a diagram showing the configuration of the gear engagement state maintenance device of the vehicle electric steering apparatus according to the present invention, the electric steering apparatus according to the present invention for transmitting the steering wheel steering force of the driver to operate the tie rod ECU 3, which receives the vehicle driving information and supplies a control current together with a steering column 1 for operating the rack mechanism 4, a sensor signal for sensing the steering intention of the driver, and a control current of the ECU 3 Tilt moving device is located in the worm shaft (6) that is connected to the reducer (2) and the motor (5) constituting the reducer (2) and engaged with the worm wheel (7) while rotating at a high speed through It consists of (11).

Here, the worm shaft 6, which is connected to the motor 5 and is engaged with the worm wheel 7 and rotates at high speed, is supported by both sides via a bearing in the worm shaft housing 8 containing the worm shaft 6. That is, bearings are positioned at worm shaft 6 portions which are connected to the motor 5 side and worm shaft 6 portions forming opposite sides, respectively, to support the worm shaft 6.

The bearings for supporting the worm shaft 6 are distinguished in their respective functions. That is, the worm shaft bearing 12 located at the worm shaft 6 connected to the motor 5 supports the worm shaft 6. The displacement bearing 20 located at the worm shaft 6 portion opposite to the motor 5 side absorbs the back lash of the reducer.

That is, the displacement bearing 20 can be moved at a constant angle and displacement (decelerator center distance) to maintain a constant gear bit rate according to the run-out and wear state of the worm wheel 7. It has a constant displacement of about 20μm ~ 100μm, so that the backlash of the reducer can be absorbed.

In addition, the tilt movement device 11 implements a tilting behavior in the worm shaft bearing 12 supporting one end portion of the worm shaft 6 connected to the motor 5 side, which is the worm shaft 6. And the other end portion of the c) is engaged with the displacement bearing 20 where a displacement of about 20 μm to 100 μm occurs (see FIG. 1 (b)).

As shown in FIG. 1B, the tilt movement device 11 includes a motor-side connecting housing 9 of a worm shaft housing 8 that receives a worm shaft 6 that rotates at high speed through a motor 5. The axial direction and absorbing the shock transmitted along with the joint according to the misalignment of the seating receiving groove 10 and the worm shaft bearing 12 and the worm shaft bearing 12 that surrounds and supports the portion of the worm shaft 6 formed It is composed of elastic means to impart axial behavior according to the axial load.

In addition, the elastic means surrounds the worm shaft bearing (12) supporting the worm shaft (6) and the bush bearing (14) located in the inner insertion groove (10a) forming a seating receiving groove (10) of the worm shaft housing (8). And a screw ring 13 for fixing both sides of the worm shaft bearing 12 and an outer screw groove having a diameter size larger than the diameter of the inner insertion groove to fix the position of the bush bearing 14. It consists of a screw plug 15.

Here, the bush bearing 14 has a displaceable inner ring 14a surrounding the worm shaft bearing 12, an outer ring 14c fitted in close contact with the inner insertion groove 10a of the seating receiving groove 10, and the inner ring 14a. ) Is provided between the outer ring 14c and the elastic body 14b to absorb shocks and impart axial behavior.

In addition, the inner ring 14a of the bush bearing 14 can be axially displaced to some extent. For this purpose, left and right free spaces b and a are formed at both sides of the bush bearing 14. As shown in FIG. 1, a right side clearance a is formed into the inner insertion groove 10a of the seating accommodation groove 10 in which the bush bearing 14 is accommodated, and the bush bearing 14 is fixed in position. The left side clearance b which made the inner diameter of the screw plug 15 larger than the diameter of the inner ring 14a is formed.

In this case, the elastic body 14b is made of various materials in which elastic deformation occurs, and typically rubber is used.

Accordingly, as shown in FIG. 2, the tilt behavior device 11 is moved upward and downward through the bush bearing 14 with respect to the center line of the worm shaft 6 (exaggerated in FIG. 2). This action can absorb the back lash of the reducer.

Hereinafter, the operation of the present invention will be described in detail with reference to the accompanying drawings.

In the electric steering apparatus of the present invention, when the motor 5 is rotated by controlling the supply current of the reduction gear 2 by the ECU 3 that receives the driver's steering information, vehicle driving information, and the like, the motor ( 5) through the worm shaft (6) that rotates at high speed through the worm wheel (7) about 10 to 20 times deceleration is made, the steering wheel steering force of the driver to generate the steering force (assist) by using the motor drive force. do.

In addition, the present invention provides the worm shaft 6 and the worm wheel 7 together with the run-out generated in the worm shaft 6 and the worm wheel 7 engaged with each other during the operation of the reducer 2. ), The worm shaft 6 can move at a constant angle and displacement (about 20 μm to 100 μm from the center of the reducer center) to maintain a constant gear bit rate regardless of wear and to absorb external impacts. It will have the feature to absorb back lash of 2).

The characteristic of this reducer 2 is according to the structure of the bearing portion for supporting the worm shaft 6, which is a worm shaft surrounding the worm shaft 6 portion connected to the motor 5 side as shown in FIG. As the bearing 12 portion mounts the tilting mechanism 11, the tilting mechanism 11 worms against the behavior of the displacement bearing 20 supporting the portion of the worm shaft 6 opposite the motor 5. This is because the shaft 6 can smoothly move in contact with the axial diameter direction of the worm wheel 7.

That is, the tilt movement device 11 provided with the worm shaft bearing 12 located in the seat receiving groove 10 formed in the worm shaft housing 8 forming the overall appearance is a bush bearing wrapped around the worm shaft bearing 12 ( The structure 14 is provided with an elastic body 14b between the inner ring 14a and the outer ring 14c to enable axial movement according to the axial direction and the axial radial load.

At this time, the bush bearing 14 is constrained by a screw plug 15 fitted to one side while surrounding the worm shaft bearing 12 fixed to both sides with a snap ring 13, the screw plug 15 is seated It is screwed and coupled through the outer screw groove 10c which is connected to the inner insertion groove 10a of the receiving groove 10.

In addition, the bush bearing 14 has a right side clearance (a) formed into the inner insertion groove (10a) of the seating receiving groove (10) and a left side clearance (b) leading to the inner diameter of the screw plug (15). In addition, the damping section of the elastic body 14b of the bush bearing 14 is limited, so that an optimum response can be realized.

The tilt mechanism 11 has a back lash absorption action of the reducer 2 through a displacement bearing 20 that has a displacement behavior of about 20 μm to 100 μm, and an axial direction according to an axial direction and an axial load. Through the bush bearing 14 imparted to the behavior it is to implement the action of absorbing the joint and the shock transmitted according to the misalignment of the worm shaft bearing 12.

That is, when the displacement bearing 20 supporting one end of the worm shaft 6 is displaced by about 20 μm to 100 μm depending on the run-out and wear state of the worm wheel 7, the displacement bearing A bush bearing 14 supporting the worm shaft 6 at the position opposite to the 20 shows the elastic deformation of the elastic body 14b provided between the inner ring 14a and the outer ring 14c, as shown in FIG. As a medium, the gear bit rate of the worm shaft 6 and the worm wheel 7 is always maintained as the worm shaft 6 supported by the displacement bearing 20 can be moved, so that the bag of the reducer 2 Back Lash can be absorbed.

At this time, the displacement bearing 20 for supporting one end of the worm shaft 6 is formed with a displacement behavior of the maximum 50μm ~ 400μm region.

In addition, the bush bearing 14 supporting the connection portion of the motor 5 side of the worm shaft 6 allows the worm shaft 6 to be displaced along the center line through the displacement bearing 20. , The axial behavior can be realized when the axial and axial load are applied, that is, the worm shaft 6 relative to the center of the worm shaft bearing 12 supporting the worm shaft 6 positioned toward the motor 5. As it rotates, the joint due to the misalignment of the worm shaft bearing 12 coupled to the worm shaft 6 can be absorbed by the action of the bush bearing 14.

This is because, as the elastic body 14b provided between the inner ring 14a and the outer ring 14c of the bush bearing 14 is arranged in the axial diameter direction, the worm shaft 6 is referred to based on the center of the worm shaft bearing 12. The worm shaft in the axial diameter direction of the worm wheel 7 through the elastic deformation behavior of the elastic body 14b acting upon rotation, that is, the axial direction and the axial diameter direction of the bush bearing 14 using the elastic body 14b. 6) acts to smoothly contact and rotate, so as to absorb the misalignment of the worm shaft bearing (12).

In addition, the elastic deformation action of the elastic body 14b provided between the inner ring 14a and the outer ring 14c of the bush bearing 14 functions as a damper for absorbing shock, that is, toward the wheel during driving. When the wheel wheel 7 receives the external force transmitted from the blown worm shaft 6, the blow applied to the worm shaft 6 is transmitted to the bush bearing 14, thereby the bush bearing 14 The elastic body 14b of the absorber absorbs the impact amount of the worm shaft 6 while generating a displacement in the direction of the worm shaft 6 and restoring to its original position.

As such, the action of the bush bearing 14 is fixed to the worm shaft bearing 12 and is fixed to the elastic body 14b through left and right clearances b and a of the inner ring 14a capable of axial movement. Although it is made, the left and right clearance space (b, a) has a double function having a stopper function to enable the displacement of the bush bearing 14 and to prevent the displacement from occurring more than a predetermined interval.

The displacement behavior of the bush bearing 14 is to improve the responsiveness of the bush bearing 14 as well as to improve the endurance life. Left and right clearances b and b formed on both sides of the bush bearing 14 are provided. The size a) has depends on the design performance of the reducer 2.

As described above, according to the present invention, the worm shaft, which is rotated at a high speed through the motor and transmits steering control force to the worm heel, is supported by a bearing capable of axial displacement at one end thereof, and the worm shaft portion connected to the motor is disposed in the axial direction and the axial diameter direction. Equipped with a deformable elastic body, it is possible to maintain the gear bit rate and prevent play even when using worm shafts and worm wheels with low grade gears to prevent back lash due to the progress of wear of the reducer. Will be.

In addition, the present invention supports the worm shaft by using an elastic body that absorbs the shock transmitted while the worm shaft of the reducer moves in the axial direction, the ratchet of the reducer through the smooth absorption of the impact applied to the worm shaft from the worm wheel (RATTLE) In addition to preventing the joint, the response of the elastic body causing the axial deformation is limited to a specific section, thereby improving the responsiveness.

In addition, according to the present invention, as the worm shaft of the reducer supports the worm shaft using an elastic body that absorbs the shock transmitted while the worm shaft behaves in the axial direction, the parts are extremely simplified, so that the pivot or bush for the same tilt is realized. There is no use of light, etc., so that the overall parts can be reduced.

Claims (5)

A reducer 2 for transmitting a steering wheel steering force of the driver to generate a rotational force for operating the steering column 1 for operating the rack mechanism 4 for operating the tie rod; An ECU 3 for receiving vehicle driving information together with a sensor signal for sensing steering of the driver and supplying a control current; A displacement bearing 20 for supporting the worm shaft 6 portion to enable the reduction gear center line behavior of the worm shaft 6 engaged with the worm wheel 7 to which the steering column 1 is coupled, and the displacement bearing 20 Tilt with elastic body surrounding the worm shaft bearing 12 so that the worm shaft bearing 12 supporting the portion of the worm shaft 6 connected to the motor 5 behaves in the axial direction and the axial diameter direction on the opposite side of the (Tilt) operating device 11; The tilt movement device 11 includes a bush bearing 14 which absorbs a shock transmitted along with a misalignment of the worm shaft bearing 12 and imparts an axial behavior according to axial and axial loads. The bush bearing 14 has a right side clearance (a) formed into the inner insertion groove (10a) of the seating receiving groove (10) and a left side clearance (b) extending toward the inner diameter of the screw plug 15, The inner ring (14a) constituting the bush bearing 14 is a vehicle electric steering apparatus with a tilting behavior type reducer, characterized in that the axial displacement is constrained. The motor side connection housing of the worm shaft housing (8) according to claim 1, wherein the tilt behavior device (11) is wrapped around the worm shaft bearing (12) for support and receives a worm shaft (6) rotating at high speed through the motor (5). A seating receiving groove 10 formed of (9); And a screw plug 15 screwed to the outer screw groove 10c having a diameter larger than the diameter size of the inner insertion groove 10a to fix the position of the bush bearing 14. Electric steering device for vehicles with a tilting behavior type reducer. The outer ring 14c of claim 1, wherein the inner ring 14a of the bush bearing 14 is displaceable by being wrapped around the worm shaft bearing 12, and is fitted in close contact with the inner insertion groove 10a of the seating receiving groove 10. And an elastic body (14b) between the inner ring (14a) and the elastic body (14b) to absorb the shock and to impart an axial behavior. delete 4. The motorized steering apparatus for a vehicle according to claim 3, wherein the elastic body (14b) is made of a rubber material.

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