CN210191580U

CN210191580U - Axial positioning device of power-assisted gear of electric power-assisted steering system for light commercial vehicle

Info

Publication number: CN210191580U
Application number: CN201920582888.2U
Authority: CN
Inventors: Jing Wang; 王静; Jigang Wu; 吴纪刚; Shun Chen; 陈顺; Ming Li; 李明; Luping Yuan; 袁鲁平; Liwei Dai; 戴立伟
Original assignee: Anhui Defu Steering System Of Ltd By Share Ltd; China Highway Vehicle and Machinery Co Ltd
Current assignee: China Highway Vehicle and Machinery Co Ltd
Priority date: 2019-04-25
Filing date: 2019-04-25
Publication date: 2020-03-27
Anticipated expiration: 2029-04-25

Abstract

The utility model discloses an axial positioning device of electronic power assisted steering system helping hand gear for light-duty commercial vehicle, locate the support bearing on the helping hand gear including the cover, the apron with set up on the apron and be used for realizing the end cover of support bearing axial fixity, the support bearing is located the inside of apron and support bearing and apron are clearance fit, reduction gears's worm wheel cover is located on the helping hand gear and the worm wheel is interference fit with the helping hand gear, support bearing is located between worm wheel and the end cover and the worm wheel contacts with support bearing. The utility model discloses light-duty commercial vehicle is with electric power steering system power assisted gear's axial positioning device cooperatees with the worm wheel through setting up apron, end cover and support bearing, realizes power assisted gear's axial positioning, need not to set up on the power assisted gear and uses the retaining ring to carry out axial positioning to worm wheel and support bearing, axial displacement can not take place for power assisted gear, and the reliability is better, reduces the risk that power assisted gear appears damaging.

Description

Axial positioning device of power-assisted gear of electric power-assisted steering system for light commercial vehicle

Technical Field

The utility model belongs to the technical field of vehicle steering system, specifically speaking, the utility model relates to an electric power steering system helping hand gear's axial positioning device for light-duty commercial vehicle.

Background

LCV-EPS is an abbreviation of Light Commercial Vehicle-Electric Power Steering, Light Commercial Vehicle, English, that is, Electric Power Steering systems for Light Commercial vehicles. The LCV-EPS is the development direction of a steering system of a light commercial vehicle, and can realize vehicle auxiliary driving functions, such as lane keeping function, lane changing auxiliary function and the like.

The LCV-EPS mainly comprises an electronic control unit, a torque and angle sensor, a power-assisted motor, a speed reducing mechanism, a steering gear, a power-assisted gear, a rack and the like. The LCV-EPS is a system which controls the running direction and torque output of a power steering motor and acts on a power-assisted gear through signal processing and data operation of an electronic control unit according to the running speed of an automobile and the direction and torque of a steering wheel rotated by a driver, the power-assisted gear and the steering gear drive a rack to move linearly together, and then the steering rod and a steering knuckle drive a tire to rotate.

Install bearing and worm wheel on the helping hand gear, adopt the retaining ring to carry out axial positioning to the worm wheel on the current helping hand gear, consequently need process the retainer groove that is used for installing the retaining ring on the helping hand gear, the bottom in retainer groove can form stress concentration, when helping hand gear output torque is great, can lead to helping hand gear to damage, and then can influence the turning to of vehicle. And because the machining precision problem of the retaining ring groove, the clearance of the axial movement of the power-assisted gear cannot be completely eliminated, so that the transmitted torque fluctuates and even abnormal sound occurs.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides an axial positioning device of electronic power assisted steering system power assisted gear for light-duty commercial vehicle, the risk that the damage appears in the purpose reduction power assisted gear.

In order to realize the purpose, the utility model discloses the technical scheme who takes does: axial positioning device of electronic power assisted steering system helping hand gear for light-duty commercial vehicle, locate the support bearing on the helping hand gear including the cover, the apron just is used for realizing the end cover of support bearing axial fixity with setting up on the apron, support bearing is located the inside of apron and support bearing and apron are clearance fit, reduction gears's worm wheel cover is located on the helping hand gear and worm wheel and helping hand gear are interference fit, support bearing is located between worm wheel and the end cover and worm wheel and support bearing contact.

The power-assisted gear comprises a gear body meshed with the rack and a shaft body connected with the gear body, the worm gear is sleeved on the shaft body, and the worm gear is in interference fit with the shaft body.

The power-assisted gear further comprises a shaft shoulder connected with the shaft body and a flange connected with the shaft shoulder, the shaft shoulder is sleeved with the supporting bearing, and the supporting bearing is located between the worm gear and the flange.

The supporting bearing is a ball bearing, the cover plate is provided with a first limiting surface attached to the first end face of the outer ring of the supporting bearing and a second limiting surface attached to the end face of the end cover, and the second end face of the outer ring of the supporting bearing is attached to the end face of the end cover.

The apron is detachable with the steering gear casing and is connected, the end cover is detachable with the apron and is connected.

The end cover is mounted on the cover plate through bolts.

The utility model discloses light-duty commercial vehicle is with electric power steering system power assisted gear's axial positioning device cooperatees with the worm wheel through setting up apron, end cover and support bearing, realizes power assisted gear's axial positioning, need not to set up on the power assisted gear and uses the retaining ring to carry out axial positioning to worm wheel and support bearing, axial displacement can not take place for power assisted gear, and the reliability is better, reduces the risk that power assisted gear appears damaging.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a cross-sectional view of an axial positioning device of a power-assisted gear of an electric power-assisted steering system for a light commercial vehicle according to the present invention;

FIG. 2 is a cross-sectional view of the cover plate and end cap in combination with the bearing;

FIG. 3 is a cross-sectional view of the cover plate;

FIG. 4 is a schematic structural view of an electric power steering system for a light commercial vehicle;

FIG. 5 is a schematic view showing an internal structure of an electric power steering system for a light commercial vehicle;

FIG. 6 is a schematic view of the connection of an electric power steering system to a steering wheel for a light commercial vehicle;

FIG. 7 is a schematic view of the steering gear and power gear meshing with the rack;

labeled as: 1. an Electronic Control Unit (ECU); 2. a steering tie rod; 3. a steering gear; 4. a power-assisted gear; 401. a gear body; 402. a shaft body; 403. a flange; 404. a shaft shoulder; 5. a rack; 501. a toothless segment; 502. rack teeth; 6. a steering housing; 7. a cover plate; 701. a large-diameter hole; 702. a bore hole; 703. a small-diameter hole; 704. a first limiting surface; 705. a second limiting surface; 8. an elastic bushing; 9. an end cap; 10. an input shaft; 11. a booster motor; 12. a worm gear; 13. a worm; 14. a steering wheel; 15. a support bearing; 16. and (4) bolts.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings, for the purpose of helping those skilled in the art to understand more completely, accurately and deeply the conception and technical solution of the present invention, and to facilitate its implementation.

It should be noted that, in the following embodiments, the terms "first", "second" and "third" do not denote absolute differences in structure and/or function, nor do they denote a sequential order of execution, but rather are used for convenience of description.

As shown in fig. 1 to 7, the utility model provides an axial positioning device of electronic power assisted steering system power assisted gear for light-duty commercial vehicle, locate support bearing 15 on power assisted gear 4 including the cover, apron 7 and set up on apron 7 and be used for realizing support bearing 15 axial fixity's end cover 9, support bearing 15 is located the inside of apron 7 and support bearing 15 and apron 7 are clearance fit, speed reduction mechanism's worm wheel 12 cover is located on power assisted gear 4 and worm wheel 12 is interference fit with power assisted gear 4, support bearing 15 is located between worm wheel 12 and the end cover 9 and worm wheel 12 contacts with support bearing 15.

Specifically, as shown in fig. 1 to 7, the electric power steering system for a light commercial vehicle includes an input shaft 10, a steering housing 6, a steering gear 3, a power gear 4, and a rack 5 movably disposed in the steering housing 6, the rack 5 including a toothed section and a non-toothed section 501, the toothed section being provided with a plurality of rack teeth 502 that are meshed with the power gear 4 and the steering gear 3 and are continuously distributed. The rack 5 is movably arranged in an inner cavity of the steering housing 6, the steering housing 6 is of a structure with two open ends and a hollow interior, the inner cavity of the steering housing 6 is a circular cavity, the inner cavity of the steering housing 6 extends from one end of the steering housing 6 to the other end along the length direction of the steering housing 6, and the diameter of the rack 5 is smaller than that of the inner cavity. Steering gear 3 and helping hand gear 4 are rotatable setting up in the inside of steering gear casing 6 and steering gear 3 and helping hand gear 4 lie in same one side of rack 5, steering gear 3 and input shaft 10 fixed connection and both are coaxial setting, steering gear 3 and input shaft 10 synchronous revolution, input shaft 10 passes through the steering column and is connected with the steering wheel with the jackshaft, the driver exerts the steering power on the steering wheel and transmits to input shaft 10 through steering column and jackshaft on, drive steering gear 3 by input shaft 10 again and rotate, and then drive rack 5 and remove, and then realize the turning to of vehicle.

As shown in fig. 4 to 7, the steering gear 3 and the power assisting gear 4 are both helical gears, and the tooth shapes of the steering gear 3 and the power assisting gear 4 are opposite in rotation direction and the helical angles are the same in size. The rack 5 is provided with one toothed section with a certain length, all the rack teeth 502 are sequentially arranged along the length direction of the toothed section and are distributed at equal intervals, and the rack teeth 502 are used for being embedded into tooth grooves between two adjacent gear teeth of the power-assisted gear 4 and the steering gear 3. The non-toothed section 501 of the rack is provided with two non-toothed sections, the toothed sections are located between the two non-toothed sections 501, the non-toothed sections 501 are not provided with rack teeth 502, the non-toothed sections 501 are cylinders with certain length, the two non-toothed sections 501 are coaxially arranged, and the steering gear 3 and the power-assisted gear 4 are also located between the two non-toothed sections 501.

As shown in fig. 4 to 7, the steering gear 3 and the power assisting gear 4 have the same module, the tooth profile of the steering gear 3 is a left-handed tooth profile, and the tooth profile of the power assisting gear 4 is a right-handed tooth profile. Rack teeth 502 are straight and have no helix angle. When the gear rack works, as the tooth form of the gear rack is a right angle, no radial acting force is exerted on the gear rack; moreover, the rotation directions of the steering gear 3 and the power-assisted gear 4 when the rack is driven to move are consistent, that is, when the rack moves linearly along the axial direction, the rotation directions of the steering gear 3 and the power-assisted gear 4 are the same, the tooth-shaped rotation directions of the steering gear 3 and the power-assisted gear 4 are opposite, and the force output by the rack in the axial direction can be ensured to be very stable. The steering gear 3 and the power-assisted gear 4 are arranged to be meshed with the rack on the same section of tooth form, so that the whole structure of the steering system is more compact, the whole length of the steering system is reduced, the cost is reduced, and the installation and the arrangement on a light commercial vehicle are facilitated.

As shown in fig. 4 to 7, the steering gear 3 and the power gear 4 respectively implement a steering function and a power function, the electric power steering system for a light commercial vehicle further includes a power motor 11 and a speed reducing mechanism connected to the power motor 11, the speed reducing mechanism is connected to the power motor 11 and the power gear 4, the speed reducing mechanism is configured to transmit a rotational force generated by the power motor 11 to the power gear 4, the power gear 4 drives a rack to perform a reciprocating linear motion in an axial direction (i.e., a length direction of the steering housing 6) in the steering housing 6, the power gear 4 is located inside the steering housing 6, and the power motor 11 is located outside the steering housing 6. The speed reducing mechanism comprises a worm wheel 12 and a worm 13 which are meshed with each other, the worm wheel 12 is sleeved on the power-assisted gear 4, the worm wheel 12 and the power-assisted gear 4 rotate synchronously, the worm 13 is rotatably arranged in the steering gear shell 6, the worm 13 is fixedly connected with a motor shaft of the power-assisted motor 11, the worm wheel 12 is positioned in the steering gear shell 6, and the power-assisted gear 4 and the worm wheel 12 are coaxially arranged. When a driver operates a steering wheel to steer a vehicle, a rack is driven by a steering gear 3 to perform linear movement, meanwhile, a power-assisted motor 11 drives a power-assisted gear 4 to rotate through a speed reducing mechanism, then the rack is driven by the power-assisted gear 4 to perform linear movement, the rack performs linear movement, wheels are pushed by a steering pull rod 2 to steer, the steering gear 3 and the power-assisted gear 4 rotate in the same direction, therefore, the rack obtains driving torque from two gears, the power-assisted motor 11 provides steering assistance, the steering operation of the driver is lighter, and the comfort of the steering operation is improved.

As shown in fig. 1 to 3, the power assisting gear 4 includes a gear body 401 engaged with the rack, a shaft body 402 connected to the gear body 401, a shoulder 404 connected to the shaft body 402, and a flange 403 connected to the shoulder 404, wherein the worm gear 12 is sleeved on the shaft body 402, and the worm gear 12 is in interference fit with the shaft body 402. The shoulder 404 is sleeved with a support bearing 15, and the support bearing 15 is located between the worm wheel 12 and the flange 403. The gear body 401 is a part meshed with rack teeth 502 of a toothed section of a rack on the power-assisted gear 4, the gear body 401 is a spiral gear, the flange 403, the shoulder 404 and the shaft body 402 are cylinders, the shaft body 402 is coaxially arranged with the shoulder 404, the flange 403 and the gear body 401, the diameter of the shaft body 402 is larger than that of the gear body 401, the diameter of the shaft body 402 is smaller than that of the shoulder 404 and that of the flange 403, the diameter of the shoulder 404 is smaller than that of the flange 403, one end of the shaft body 402 is fixedly connected with the gear body 401, the other end of the shaft body 402 is fixedly connected with one end of the shoulder 404, and the other end of the shoulder 404 is fixedly connected with the flange 403. The steering gear housing 6 is provided with a containing cavity for containing the power-assisted gear 4 and the worm wheel 12, an opening is formed on the outer surface of the steering gear housing 6, the cover plate 7 is arranged at the opening, the cover plate 7 is used for sealing the opening, and the cover plate 7 is detachably connected with the steering gear housing 6. Support bearing 15 is ball bearing, and support bearing 15 and worm wheel 12 are interference fit with helping hand gear 4, and support bearing 15's inner circle cover is located on the shaft shoulder 404, and on axle body 402 was located to worm wheel 12 cover, the both ends terminal surface of support bearing 15's inner circle was laminated with worm wheel 12 and flange 403 respectively, need not to set up on the helping hand gear 4 like this and uses the retaining ring to carry out axial positioning to worm wheel 12 and support bearing 15. If a retainer ring groove is processed on the power-assisted gear 4 for installing a retainer ring, stress concentration can be formed at the bottom of the retainer ring groove, and the power-assisted gear 4 can be damaged when the output torque of the power-assisted gear 4 is larger. If the retainer ring is used for axial positioning on the power-assisted gear 4, the clearance of axial movement of the power-assisted pinion cannot be completely eliminated due to the problem of machining precision of the retainer ring groove, so that transmitted torque fluctuates and even abnormal sound occurs.

In the present embodiment, in order to eliminate the above two problems, the mounting position of the support bearing 15 is set between the flange 403 of the booster gear 4 and the worm wheel 12, and the flange 403 and the shoulder 404 of the booster gear 4 are directly flattened against the end face of the inner race of the support bearing 15 and the end face of the worm wheel 12, respectively, at the time of assembly. Because the axial pressing force applied when the worm wheel 12 is in interference fit with the power-assisted gear 4 is far larger than the axial force generated when the power-assisted gear 4 is meshed with the rack, the power-assisted gear 4 and the worm wheel 12 are firmly fixed, the power-assisted gear 4 cannot move axially, and the reliability is better. And the booster gear 4 does not use a retainer ring to axially position the worm wheel 12 and the bearing, so that the cost of a retainer ring part is saved, the machining cost of a retainer ring groove is also saved, the assembling process is simple, and the assembling cost is also reduced.

As shown in fig. 4 and 5, the cover plate 7 is attached to the steering housing 6 by a plurality of bolts 16, and is easily attached and detached, and the cover plate 7 has through holes through which the bolts 16 are inserted, and the steering housing 6 has female screw holes through which the bolts 16 are inserted.

As shown in fig. 1 to 3, the cover plate 7 is a circular ring structure, the support bearing 15 and the flange 403 are located in a central hole of the cover plate 7, the cover plate 7 and the power assisting gear 4 are coaxially arranged, the end cover 9 is mounted on the cover plate 7, the end cover 9 is used for closing a circular opening formed on the end face of the cover plate 7 by the central hole of the cover plate 7, the end cover 9 is inserted into the central hole of the cover plate 7, and the central hole of the cover plate 7 is a circular hole located at the center of the cover plate 7. The cover plate 7 has a first limit surface 704 attached to the first end surface of the outer ring of the support bearing 15 and a second limit surface 705 attached to the end surface of the end cover 9, the second end surface of the outer ring of the support bearing 15 is attached to the end surface of the end cover 9, and the end surface of the end cover 9 is attached to the second limit surface 705. The center hole of the cover plate 7 includes a large-diameter hole 701, a medium-diameter hole 702 and a small-diameter hole 703 that are sequentially arranged and communicated in the axial direction, the large-diameter hole 701, the medium-diameter hole 702 and the small-diameter hole 703 are circular holes, the diameters of the large-diameter hole 701, the medium-diameter hole 702 and the small-diameter hole 703 are sequentially reduced, the diameter of the large-diameter hole 701 is the diameter of the medium-diameter hole 702, the diameter of the medium-diameter hole 702 is larger than the diameter of the small-diameter hole 703, the medium-diameter hole 702 is located between the large-diameter hole 701 and the small-diameter hole 703, the small-diameter hole 703 is located between the worm wheel 12 and the medium-diameter hole 702, the support bearing 15 is located in the medium-. The first limiting surface 704 is a step surface formed between the small-diameter hole 703 and the medium-diameter hole 702, the second limiting surface 705 is a step surface formed between the medium-diameter hole 702 and the large-diameter hole 701, the first limiting surface 704 and the second limiting surface 705 are both circular planes, a first end surface and a second end surface of an outer ring of the support bearing 15 are end surfaces of two opposite ends of the outer ring, the second end surface of the outer ring is attached to an end surface of an end portion, inserted into the large-diameter hole 701, of the end cover 9, the end cover 9 compresses the support bearing 15, and axial positioning of the support bearing 15 is achieved through matching of the end cover 9 and the cover plate 7.

As shown in fig. 1 to 3, the support bearing 15 is in clearance fit with the cover plate 7, and during assembly, the end cover 9 is mounted on the cover plate 7 through another two bolts, and the end cover 9 and the cover plate 7 form detachable connection, so that the assembly and disassembly are convenient. The end face of the end cap 9 is fitted to an end face of the outer ring of the support bearing 15, so that the support bearing 15 is axially fixed. The support bearing 15 is in clearance fit with the cover plate 7, and the end cover 9 is in clearance fit with the cover plate 7, so that the assembly is convenient. The end cover 9 adopts a mode of pressing by two bolts, and is simple and reliable. The first end face of the outer ring of the support bearing 15 is attached to the first limit face 704 of the cover plate 7, and the end face of one end of the inner ring of the support bearing 15 is attached to the end face of the worm wheel 12, so that the tolerance of the thickness of the support bearing 15 is directly eliminated from the assembly dimension chain, and the center line coincidence of the worm wheel 12 and the worm 13 (the center of the worm 13 is determined, and the dimension a is the vertical distance between the center of the worm 13 and the second limit face 705) can be ensured only by controlling the processing precision of the dimension B (the dimension B is the vertical distance between the first limit face 704 and the second limit face 705) in fig. 2, thereby ensuring the assembly precision, being simple in process and convenient to process.

The invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-described manner. Various insubstantial improvements are made by adopting the method conception and the technical proposal of the utility model; or without improvement, the above conception and technical solution of the present invention can be directly applied to other occasions, all within the protection scope of the present invention.

Claims

1. Light-duty commercial automobile-used electric power steering system helping hand gear's axial positioning device, its characterized in that: the supporting bearing is sleeved on the power-assisted gear, the cover plate and the end cover is arranged on the cover plate and used for achieving axial fixing of the supporting bearing, the supporting bearing is located inside the cover plate, the supporting bearing and the cover plate are in clearance fit, the worm wheel of the speed reducing mechanism is sleeved on the power-assisted gear, the worm wheel and the power-assisted gear are in interference fit, the supporting bearing is located between the worm wheel and the end cover, and the worm wheel is in contact with the supporting bearing.

2. The axial positioning device for a power assisted gear of an electric power steering system for a light commercial vehicle according to claim 1, characterized in that: the power-assisted gear comprises a gear body meshed with the rack and a shaft body connected with the gear body, the worm gear is sleeved on the shaft body, and the worm gear is in interference fit with the shaft body.

3. The axial positioning device for a power assisted gear of an electric power steering system for a light commercial vehicle according to claim 2, characterized in that: the power-assisted gear further comprises a shaft shoulder connected with the shaft body and a flange connected with the shaft shoulder, the shaft shoulder is sleeved with the supporting bearing, and the supporting bearing is located between the worm gear and the flange.

4. The axial positioning device of power-assisted gear of electric power-assisted steering system for light commercial vehicle according to any one of claims 1 to 3, characterized in that: the supporting bearing is a ball bearing, the cover plate is provided with a first limiting surface attached to the first end face of the outer ring of the supporting bearing and a second limiting surface attached to the end face of the end cover, and the second end face of the outer ring of the supporting bearing is attached to the end face of the end cover.

5. The axial positioning device of power-assisted gear of electric power-assisted steering system for light commercial vehicle according to any one of claims 1 to 3, characterized in that: the apron is detachable with the steering gear casing and is connected, the end cover is detachable with the apron and is connected.

6. The axial positioning device for a power assisted gear of an electric power steering system for a light commercial vehicle according to claim 5, characterized in that: the end cover is mounted on the cover plate through bolts.