KR101303460B1 - Gear's teeth contact upkeep typed motor driven power steering system in vehicle - Google Patents

Abstract

The present invention relates to a gear engagement state maintaining device of a vehicle electric steering apparatus, by providing an elastic force that presses the worm shaft toward the worm wheel in the mounted state to continuously remove the play caused by the wear between the worm shaft and the worm wheel gear, the gear between the worm shaft and the worm wheel Its purpose is to prevent rattle noise by maintaining accurate bite, regardless of the degree of wear, while also eliminating the restrictions associated with the use of special bearings such as self-aligning bearings.

The present invention for achieving the above object, the housing to be rotated through the drive means 1 for controlling the motor 2 by the ECU to convert the steering force of the driver to the rotational force of the motor 2 to generate a steering force (4) In the electric steering apparatus which consists of the worm shaft 3 accommodated in the bearing and supported by the bearing, and the worm wheel 5 which meshes with the said worm shaft 3, and transmits the driving force of the motor 2 to a gear mechanism,

The worm shaft support end 3a formed at the end portion coupled to the motor 2 shaft on the opposite side of the worm shaft 3 portion rotatably supported by the housing 4 has the worm shaft 3 toward the worm wheel 5 engaged with each other. Pressing while moving in the axial direction is characterized in that the clearance adjusting device 6 is further provided to absorb the clearance caused by the wear of the gear tooth between the worm wheel 5 and the worm shaft (3).

Description

Gear's teeth contact upkeep typed motor driven power steering system in vehicle}

1 is a block diagram of a gear engagement state maintaining device of a vehicle electric steering apparatus according to the present invention

2 is a block diagram of a clearance holding device for maintaining the gear engagement state between the worm and the worm wheel according to the present invention

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

1: driving means 2: motor

3: worm shaft 3a: worm shaft support end

3b: bearing seating end 4: housing

4a: Worm shaft receiving end 4b: Bearing receiving end

4c: Bush Pressing End 5: Worm Wheel

6: play control device 7: worm shaft bearing

8: Bearing holder 8a, 10a ', 10b': Contact surface

9: elastic support member 9a: inner member

9b: intermediate member 9c: outer member

10: tilt guider 10a, 10b: left and right guider member

11: inner bush 12: outer bush

13: snap ring

The present invention relates to an electric steering apparatus for a vehicle, and more particularly, to a gear engagement state maintaining apparatus of an electric steering apparatus for a vehicle, which is capable of always maintaining a meshing state between a worm shaft and a worm wheel that transmits a steering operation.

In general, a power steering device that generates steering force of a vehicle is designed and operated to use hydraulic pressure in order to enable quick steering while making the steering wheel light and smooth.

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 wheels may not vibrate precisely, resulting in 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. As the self-aligning bearing has a large internal clearance, the overall size of the self-aligning bearing has to be increased, and when it is necessary to make it as compact as possible, such as an electric steering device, the size of a device including a worm shaft and a worm wheel is increased. Unless it is large, the large size of the self-aligning bearings themselves implies that they cannot be mounted.

Accordingly, the present invention has been made in view of the above-mentioned point, and by providing an elastic force for pressing the worm shaft toward the worm wheel in a mounted state, by continuously removing the play caused by the wear between the worm shaft and the worm wheel gear, the degree of wear of the gear teeth between the worm shaft and the worm wheel Regardless of the purpose, the purpose is to maintain the precise bite of the gears to prevent rattle noise, while eliminating the limitations of using special bearings such as self-aligning bearings.

In order to achieve the above object, the present invention provides a motorized steering apparatus for a vehicle to control a motor by a controller (ECU) that receives information about a steering wheel steering angle, a steering torque, and a vehicle state, thereby converting a driver's steering force into a rotational force of the motor. Drive means for converting and generating steering force;

A worm shaft coupled to the motor shaft to receive rotational force in a housing accommodating the motor;

A worm wheel engaged with the worm shaft and transmitting a steering driving force to a gear mechanism for performing steering;

The worm shaft, which forms a worm shaft support end on which the end portion coupled to the motor shaft inside the housing is rotatably supported by the worm shaft bearing, is pressed while moving toward the worm wheel engaged with each other by continuously applying elastic restoring force to the worm shaft bearing. A clearance adjustment device configured to absorb a clearance due to wear of the gear tooth between the shaft and the worm shaft;

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The clearance adjusting device includes a worm shaft bearing for supporting a worm shaft which is rotated by being coupled to a bearing seating end of the worm shaft support end of the worm shaft at a bearing receiving end portion of the housing accommodating the worm shaft, and the worm shaft bearing therein. A bearing holder which is wrapped in a housing, a tilt guider which accommodates the bearing holders with a moving interval moved to be in close contact with each other through an external force applied while being inserted into the bearing receiving end of the housing, and positioned at the bearing receiving end of the housing Elastic support members that are in close contact with both sides of the worm shaft bearings, bearing holders, and tilt guiders coupled to each other, and bush press-fitting ends and worm shaft receiving ends that are connected to the bearing receiving ends of the housing to press and fix both sides of the elastic support members. It is characterized by consisting of a pair of bush member.

In addition, the tilt guider is made of a left and right guider member for accommodating the bearing holder wrapped around the worm shaft bearing with a moving interval moved to be in close contact with each other through the external force applied from the outer member forming the elastic support member, the left The right guider member is characterized in that a contact surface having a shape in close contact with a contact surface forming a convex central arc-shaped outer surface of a bearing holder surrounding a worm shaft bearing in a coupled state is formed as an inner surface thereof.

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

1 is a block diagram of a gear engagement state maintaining device of a vehicle electric steering apparatus according to the present invention, the present invention controls the motor (2) by the ECU to control the steering force of the driver by the rotational force of the motor (2) Gear mechanism which is accommodated in the housing 4 and supported by a bearing so as to be rotated through the driving means 1 which generates a steering force by converting into a gear, and is engaged with the worm shaft 3 so as to drive the driving force of the motor 2. In the electric steering device which consists of a worm wheel 5 which transmits to the side,

The worm shaft support end 3a formed at the end portion coupled to the motor 2 shaft on the opposite side of the worm shaft 3 portion rotatably supported by the housing 4 is pressed while moving the worm shaft toward the interlocking worm wheel 5. The worm wheel 5 and the worm shaft 3 is characterized in that the clearance adjustment device 6 is further provided to absorb the clearance due to the wear of the gear teeth.

That is, the clearance adjusting device 6 uses the internal structure of the housing 4 in which the bearing receiving end 4b and the bush press fitting end 4c which are connected to the worm shaft receiving end 4a are formed step by step. While supporting the worm shaft support end 3a, which is an end portion of the worm shaft, the worm shaft support end 3a acts to press the worm shaft support end 3a toward the worm wheel 5 along with the axial movement. Even if the gear between the worm wheel (5) and the worm shaft (3) is always engaged to keep the meshing state.

The clearance adjusting device 6 is coupled to the bearing seating end 3b of the worm shaft support end 3a of the worm shaft 3 at the bearing receiving end 4b of the housing 4 as shown in FIG. 2. And a worm shaft bearing 7 supporting the worm shaft 3 to be rotated, a bearing holder 8 for receiving and wrapping the worm shaft bearing 7 therein, and inserted into an inner bearing receiving end 4b of the housing 4. Tilt guider 10 for receiving bearing holder 8 with a moving interval t moved in close contact with each other through an external force applied in a state, and located in the bearing receiving end 4b inside the housing 4 The pair of worm shaft bearings 7 and the bearing holder 8 and the tilt guider 10 which are in close contact with both sides of the coupled worm shaft bearing 7 and both sides of the elastic support member 9 while being fixed while pressing It is composed of a bush member.

At this time, the elastic support member (9) is composed of an independent plurality in close contact with both sides of the worm shaft bearing 7 and the bearing holder 8 and the tilt guider 10, that is, both sides of the worm shaft bearing (7) An inner member 9a which is in close contact with the inner member 9a, an intermediate member 9b and a bearing holder 8 which are in close contact with both side portions of the worm shaft bearing 7 and the bearing holder 8 by receiving the inner member 9a; In addition, it is composed of an outer member (9c) in close contact with both sides of the tilt guider (10).

Here, the outer member (9c) is fitted to the inner bearing receiving end (4b) of the housing (4) in the compressed state at the time of initial installation, to continuously apply a force to narrow the movement interval (t) of the tilt guider (10) do.

In addition, the inner member 9a, the intermediate member 9b, and the outer member 9c constituting the elastic support member 9 are all made of a material having compressive and resilient elastic force.

In addition, the tilt guider 10 is a bearing wrapped around the worm shaft bearing (7) with a moving interval (t) which is moved in close contact with each other through the external force applied from the outer member (9c) forming the elastic support member (9) The left and right guider members (10a, 10b) for receiving the holder 8, the left and right guider members (10a, 10b) of the bearing holder (8) wrapped around the worm shaft bearing (7) in a coupled state Contact surfaces 10a 'and 10b' having a shape in close contact with the contact surfaces 8a forming the convex central arc-shaped outer surfaces are provided as the inner surfaces thereof.

In addition, the bush member is fixed while pressing both sides of the elastic support member 9, that is, the elastic support is fixed to the worm shaft receiving end (4a) formed inside the housing (4) inserted into the bearing receiving end (4b) Inner bush 11 for pressing and fixing the side of the member 9 and a bush connected to the bearing receiving end 4b to press and fix the side of the elastic support member 9 inserted into the bearing receiving end 4b. The outer bush 12 is inserted into the press-fit end 4c.

At this time, the inner bush 11 is fixed using a snap ring 13 fitted to the worm shaft support end 3a of the worm shaft 3 to prevent the positional deviation.

In addition, the outer bush 12 constituting the bush member is to be fitted to the elastic support member 9 in a compressed state, which is made of a rubber material elastic support member 9 is compressed and deformed to accommodate the bearing of the housing (4) As the width of the end 4b is greater than the width of the end 4b, the protruding portion of the outer member 9c constituting the elastic support member 9 inserted into the bearing accommodation end 4b, as shown in FIG. Is strongly compressed by the outer bush 12 (or the outer member 9c may be inserted into a state in which the outer member 9c is first deformed) to be fitted in the deformed state.

As a result, the elastic support member 9 continuously pushes the right guider member 10b of the tilt guider 10 toward the left guider member 10a through elastic restoring force, and such pressing force is applied to the bearing holder 8 and the left. The structural features of the contact surfaces 8a, 10a 'and 10b' of the right guider members 10a and 10b allow the bearing holder 8 to press the worm shaft bearing 7 while moving in the axial direction.

At this time, the profile of the contact surfaces 8a, 10a ', 10b' of the bearing holder 8 and the left and right guider members 10a, 10b is pressed while moving the worm shaft bearing 7 toward the worm wheel 5. In addition to acting as shown in Figure 1, when the tilting (tilting) operation does not act as a resistance to the operation direction, and also the behavior of the worm shaft bearing (7) portion during the tilting (tilting) operation is the elastic support member (9) is absorbed through the elasticity.

In addition, the inner bushing 11 positioned opposite to the outer bushing 12 restrains the position of the inner member 9a positioned at the innermost portion of the elastic support member 9.

And, the conventional spring prevention means (Rattle Spring) is to use the elastic force to eliminate the gap (Gap) between the worm shaft (3) and the worm wheel (5), the end of the worm shaft (3) (the opposite of the motor connection portion) Part) is provided to press toward the worm wheel 5.

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

The present invention provides a light and comfortable steering feeling at low speed by driving the motor in the electronic control unit (ECU) according to the driving conditions of the vehicle detected by the vehicle speed sensor and the steering torque sensor in the same way as a general electric steering device, It provides heavy steering feeling and good directional stability when driving at high speed, and performs a function to make rapid steering in emergency situations, and the description of such a normal operation is omitted and the gears of the worm shaft 3 and the worm wheel 5 are omitted. The clearance control device 6 which absorbs the clearance resulting from this abrasion is demonstrated.

That is, the present invention by moving the worm shaft (3) to transfer the rotational force of the motor (2) to the worm wheel (5) coupled to the steering column to the worm wheel (5) to eliminate the clearance between the gears, which is the housing (4) As the worm shaft bearing (7) supporting the worm shaft (3) inside receives a moving force and a pressing force in the axial direction of the worm wheel (5) continuously, the gears of the worm shaft (3) and the worm wheel (5) are worn out for a long time. Gap due to, of course, the function of maintaining the meshing of the gear between the worm shaft (3) and the worm wheel (5) even when the tilt (Tilt) operation in the state of the play by the wear as described above.

The play control device 6 which performs such an action through elastic deformation is generated as it is assembled with a strong compression during initial assembly, which is a bearing seating end of the worm shaft support end 3a, which is an end portion of the worm shaft 3. The worm shaft bearing 7 coupled to (3b) forms the elastic support member 9 in a state in which the bearing holder 8 and the tilt guider 10 are piled up at the inner bearing receiving end 4b of the housing 4. The outer member 9c accommodating the inner member 9a and the intermediate member 9b is fitted to be in close contact with both sides of the bearing holder 8 and the tilt guider 10.

At this time, the left and right guider members 10a and 10b constituting the tilt guider 10 are convex centers of the bearing holder 8 wrapping the worm shaft bearing 7 through the contact surfaces 10a 'and 10b' of the inner surface thereof. Although closely contacted with the contact surface 8a constituting the arcuate outer surface, the end portions of the left and right guider members 10a and 10b are not in contact with each other, but are kept spaced apart at a predetermined interval of movement interval t.

As illustrated in FIG. 2, the outer member 9c of the elastic support member 9 is in close contact with both side surfaces of the bearing holder 8 and the tilt guider 10. 4) Compression deformation of the outer member 9c while being positioned as a bush press-fit end 4c connected to the inner bearing accommodation end 4b.

At this time, the compression deformation of the outer member (9c) is made at the time of assembling the outer bush 12, or inserted into the bearing receiving end (4b) inside the housing (4) in the state in which the outer member (9c) is precompressed. You can do it.

As the outer member 9c is fitted in the compression-deformed state as described above, the worm shaft 3 is continuously pressed toward the worm wheel 5, and accordingly, the gears of the worm shaft 3 and the worm wheel 5 according to the operation progress. This wear is compensated by the elastic restoring force of the elastic support member 9 fitted in the compressed state, that is, the gap formed by the wear of the gears of the worm shaft 3 and the worm wheel 5 is elastic support member 9 The outer member 9c is compensated as it is generated by moving by the play (expanded in the compressed state).

As shown in FIG. 2, when the outer member 9c of the elastic support member 9 moves to the expanded position a, the right guider member of the tilt guider 10 receives a pressing force from the outer member 9c. 10b is moved by the expansion position a and is converted to the movement position b. The axial movement force of the right guider member 10b is lowered while moving the bearing holder 8 toward the worm wheel 5. It is converted into a pressing force in the direction.

That is, the arc-shaped structure of the contact surface 10b 'of the right guider member 10b and the contact surface 8a of the bearing holder 8 has an axial movement force of the right guider member 10b on the bearing holder 8. It is converted to the downward movement interval (c), and the downward movement interval (c) of the bearing holder (8) is converted back to the pressing force while pressing the worm shaft bearing (7) in the axial direction of the worm wheel, thereby While the axial movement component of the worm shaft 3 to which the worm shaft bearing 7 is coupled is in close contact with the gear of the worm wheel 5, the movement component that is pressed downwards at the same time acts toward the worm wheel 5.

Thus, the clearance gap formed by the wear of the gear of the worm shaft 3 and the worm wheel 5 is elastic support member 9 which converts the worm shaft 3 into the pressing force which presses while moving in the axial direction of the worm wheel 5. Absorbed by its own elastic restoring force, the worm shaft (3) and the worm wheel (5) are able to continuously maintain the engagement without gap, regardless of wear of the gear, so that the worm shaft (3) and the interlocking rotation Rattle noise due to the clearance between gears between the wormhills 5 is not generated.

As described above, according to the present invention, by using the elastic restoring force of the elastic member fitted to the worm shaft portion in a compressed state, by pressing the worm shaft supported by the bearing in the motor portion toward the engaged worm wheel, the worm shaft and the worm wheel according to the operation Since the gear continuously absorbs the play formed by the wear, the gear is able to continuously maintain the engagement without the play regardless of the wear, thereby preventing the occurrence of rattle noise.

In addition, the present invention uses a special bearing, such as a self-aligning bearing that implements the correct engagement between the worm shaft and the worm wheel while supporting the worm shaft, and uses a general bearing having only a function for supporting the worm shaft, the motor and the worm shaft and the worm wheel As the size can be made more compact, there is no effect of increasing the cost of using a special bearing.

Claims (10)

A driving means (1) for controlling steering of the motor (2) through the ECU receiving information on steering wheel steering angle, steering torque and vehicle condition to convert the steering force of the driver into the rotational force of the motor (2) to generate steering force; Worm shaft (3) in which the end portion coupled to the motor shaft in the housing (4) containing the motor (2) receives the rotational force by the worm shaft support end (3a), which is rotatably supported by the worm shaft bearing (7). And a worm wheel 5 which is engaged with the worm shaft 3 and transmits a steering driving force to a gear mechanism for performing steering. The worm shaft is coupled to the bearing seating end (3b) of the worm shaft support end (3a) at the bearing receiving end (4b) portion of the housing (4) to the worm shaft receiving end (4a) of the housing (4) for receiving the worm shaft (3) 3) a worm shaft bearing (7) supporting the bearing, a bearing holder (8) for receiving and wrapping the worm shaft bearing (7) therein, and an external force applied in the state inserted into the bearing receiving end (4b). Tilt guider 10 accommodating the bearing holder 8 with a movement interval t moved in close contact, and a worm shaft bearing 7 and a bearing holder 8 positioned at the bearing receiving end 4b and coupled to each other. And the elastic support member 9 which is in close contact with both sides of the tilt guider 10 and the bush press-fit end 4c and the worm shaft receiving end 4a which are connected to the bearing receiving end 4b. It is composed of a pair of bush member for fixing while pressing both sides of 9), elastic to the worm shaft bearing (7) Continuously applied while moving the pressing worm 5 is engaged with the worm wheel (3) to each other wimhwil 5 and the worm 3, the clearance adjustment device (6) to absorb the play between the gear according to the wear thereof, the plateau force; Gear engagement state maintenance device of a vehicle electric steering apparatus comprising a. delete The electric steering apparatus for a vehicle according to claim 1, wherein the worm shaft receiving end 4a, the bearing receiving end 4b, and the bush press fitting end 4c formed in the housing 4 are increased in stages. Gear-tooth condition retainer. The method of claim 1, wherein the elastic support member (9) is a vehicle electric steering, characterized in that coupled to the worm shaft bearing 7 and the bearing holder (8) and the independent plurality in close contact with both sides of the tilt guider (10) Gear engagement status of the device. The worm shaft bearing (7) and the bearing holder (8) of claim 4, wherein the elastic support member (9) accommodates the inner member (9a) in close contact with both sides of the worm shaft bearing (7) and the inner member (9a). Of the intermediate member 9b and the bearing holder 8, which are in close contact with both side portions of the vehicle, and an outer member 9c which is in close contact with both sides of the tilt guider 10. Gear engagement status. According to claim 5, The outer member (9c) at the time of initial mounting, it is inserted into the bearing receiving end (4b) in the housing 4 in a compressed state to continue the force for narrowing the movement interval (t) of the tilt guider (10) Gear engagement state maintenance device of a vehicle electric steering apparatus, characterized in that applied to. The electric steering apparatus for a vehicle according to claim 5, wherein the inner member 9a, the intermediate member 9b, and the outer member 9c constituting the elastic support member 9 are made of a material having compression and restoring elasticity. Gear-tooth condition retainer. The worm shaft bearing (7) of claim 1, wherein the tilt guider (10) has a movement interval (t) which is moved in close contact with each other through an external force applied from the outer member (9c) forming the elastic support member (9). It consists of left and right guider members (10a, 10b) for accommodating the bearing holder (8) wrapped around the bearing holder, the left and right guider members (10a, 10b) is a bearing holder for wrapping the worm shaft bearing (7) in a combined state ( A gear engagement state maintaining device for an electric steering apparatus for a vehicle, characterized in that a contact surface (10a ', 10b') having a shape in close contact with a contact surface (8a) forming a convex central arc-shaped outer surface of 8) is formed as an inner surface thereof. The inner bush according to claim 1, wherein the bush member is fixed to the worm shaft receiving end 4a formed in the housing 4 to press and fix the side surface of the elastic support member 9 inserted into the bearing receiving end 4b. (11) and the outer bush 12 inserted into the bush pressing end 4c connected to the bearing receiving end 4b so as to pressurize and fix the side surface of the elastic support member 9 inserted into the bearing receiving end 4b. Gear engagement state maintenance device of a vehicle electric steering apparatus, characterized in that consisting of. 10. The gear mesh of the electric power steering apparatus for a vehicle according to claim 9, wherein the inner bush 11 is fixed by using a snap ring 13 fitted to the worm shaft support end 3a of the worm shaft 3 so as to prevent the positional deviation. State maintainer.

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