CN210526637U

CN210526637U - Automobile electric steering system with built-in self-gap-adjusting structure

Info

Publication number: CN210526637U
Application number: CN201920901339.7U
Authority: CN
Inventors: 吴俊�; 贾红伟; 蔡双飞; 王亮; 李勇; 张在升
Original assignee: Nanjing Automobile Group Corp; SAIC Maxus Vehicle Co Ltd Nanjing Branch
Current assignee: Nanjing Automobile Group Corp; SAIC Maxus Vehicle Co Ltd Nanjing Branch
Priority date: 2019-06-14
Filing date: 2019-06-14
Publication date: 2020-05-15
Anticipated expiration: 2029-06-14

Abstract

The utility model relates to a built-in auto-adjusting clearance structure's auto electric steering system, mainly be the worm gear structure that adopts adjustable centre-to-centre spacing formula in EPS reduction gears, worm-gear shaft subassembly is radially retrained completely, the aligning subassembly of worm subassembly one end has certain clearance of floating with the worm, the oscillating bearing of the other end makes the worm possess certain swing degree of freedom, thereby make the meshing position of worm and worm wheel have certain radial degree of freedom, and the continuous radial pressure that produces through the spring that is in compression state in the aligning subassembly, make the worm produce the trend that constantly is close to the worm wheel. The structure can automatically eliminate the worm and gear transmission clearance generated by material abrasion or environmental temperature change.

Description

Automobile electric steering system with built-in self-gap-adjusting structure

Technical Field

The utility model relates to a steering system, specifically automobile electric steering system of built-in self-adjusting gap structure that is specifically.

Background

In recent years, an electric power steering system (hereinafter referred to as an "EPS", fig. 1) has been more and more widely used in each vehicle type, the loading of the EPS has rapidly increased, and the EPS has completely replaced a conventional HPS (hydraulic power steering system) to become a mainstream power steering technology in the automobile industry. Compared with HPS, EPS has the advantages of energy conservation, emission reduction and more excellent comprehensive operation performance. The EPS is that the torque of a motor is amplified through a worm gear and worm reduction mechanism to realize steering power assistance, poor meshing performance of a worm gear and worm transmission pair can directly cause abnormal sound to be easily generated when a vehicle passes through a bumpy road surface, particularly, an electric power steering column is close to a driver because a power assistance unit (shown in figure 2) is arranged in the cab, and the abnormal sound is more easily perceived by the driver to influence driving comfort.

The EPS generates abnormal noise due to a large meshing gap between a worm wheel and a worm (fig. 3) in the speed reducing mechanism. In the speed reducing mechanism of the traditional EPS, in order to meet the stability of torque transmission, two ends of a meshing part of a worm wheel and a worm are respectively fixed by adopting ball bearings, the worm is usually made of alloy steel, and the worm wheel is made of injection molding nylon. The center distance of the worm gear with the structure is fixed (figure 4), the relative displacement of the meshing part of the worm gear transmission pair is large in normal work, the meshing clearance can be gradually increased due to the lower wear resistance of the nylon material of the worm gear, and therefore when the EPS is in the later period of the service life, the occurrence frequency of abnormal sound can be greatly improved. In addition, when the environmental temperature changes greatly, the meshing gap of the material can also change due to expansion with heat and contraction with cold, and under a low-temperature environment, the meshing gap of the worm and gear becomes larger due to the contraction of the material, so that abnormal sound is easily generated; in a high-temperature environment, the meshing gap causes an increase in the meshing friction force due to expansion of the material, resulting in a decrease in steering performance.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that overcome prior art's shortcoming, provide a built-in auto adjustment gap structure's auto electric steering system.

In order to solve the technical problem, the utility model provides an automobile electric steering system with a built-in self-adjusting gap structure, which mainly adopts a worm gear structure with an adjustable center distance in an EPS (electric power steering) speed reducing mechanism, and comprises a speed reducing box body, and a worm gear shaft assembly and a worm assembly which are arranged in the speed reducing box body and are mutually meshed; wherein the worm gear shaft component is fixed, and the worm component is adjustable in radial direction;

the worm wheel shaft assembly comprises a worm wheel, a worm wheel shaft, a ball bearing A and a ball bearing B, wherein the ball bearing A, the worm wheel and the ball bearing B are fixed on the worm wheel shaft from top to bottom in an interference fit mode in sequence, and the worm wheel shaft assembly is fixed in the reduction box body through an upper ball bearing and a lower ball bearing;

the worm assembly comprises a worm, a swing bearing, a limiting clamp spring, an aligning assembly, an O-shaped ring and a damping washer, wherein the swing bearing is fixed at one end of the worm through the limiting clamp spring, the aligning assembly is fixed at the other end of the worm, and a radial floating gap is formed through the O-shaped ring between the aligning assembly and the worm;

the aligning assembly comprises a ball bearing C, a bearing bush, a bush support, a spring and a shell, the ball bearing C and the bearing bush are located at one end of the shell, the bearing bush, the bush support and the spring are located at the other end of the shell, the bush support is a cylindrical boss along the radial direction, the distance between the bottom surface of the boss of the bush support and the inner wall of the shell is smaller than the free length of the spring after the bearing bush, the bush support and the spring are assembled in place, and the spring is subjected to energy storage deformation to form continuous radial pressure.

The utility model discloses the technical scheme who further injects is:

further, the worm wheel shaft assembly is radially constrained in the reduction box body; the aligning component and the worm of worm subassembly one end have certain clearance of floating, and the oscillating bearing of the worm subassembly other end makes the worm possess certain swing degree of freedom, and there is certain radial degree of freedom in the meshing position of worm and worm wheel this moment, and the continuous radial pressure that is in compression state's spring production in the aligning component makes the worm produce the trend that constantly is close to the worm wheel.

Furthermore, when the worm wheel and the worm generate a gap due to friction or reduction of ambient temperature, the worm approaches the worm wheel under the action of radial pressure of a spring in the aligning component to reduce the center distance; when the environmental temperature rises, the worm retracts relative to the worm wheel along the radial direction due to the fact that a certain radial degree of freedom exists in the meshing position of the worm and the worm wheel due to material expansion, and the meshing friction force of the worm and the worm is almost unchanged due to the fact that the deformation amount of the spring is small.

Furthermore, a certain floating gap exists between the worm and the aligning component through an O-shaped ring.

The utility model has the advantages that: 1. the factory state of the clearance between the worm and the gear of the EPS reducing mechanism is controlled within 5' usually, the clearance between the worm and the gear of the EPS reducing mechanism with the traditional fixed center distance structure can reach more than 1 degree after the fatigue endurance test, and by adopting the technology of the utility model, the clearance between the worm and the gear is almost not changed before and after the fatigue endurance test, thereby thoroughly avoiding the EPS abnormal sound caused by the abrasion of the transmission pair; 2. when the traditional EPS reducing mechanism with the fixed center distance structure is in a low-temperature environment (below minus 30 ℃), compared with a normal-temperature environment, part of worm and gear gaps can be increased by more than 3', and by adopting the technology of the utility model, the low-temperature environment hardly has influence on the worm and gear gaps; 3. when traditional fixed centre-to-centre spacing structure's EPS reduction gears was in high temperature environment (more than 40 ℃), worm gear's meshing frictional force increase not only can influence turn to and feel, more can aggravate the vice wearing and tearing of transmission, reduces product life, and the utility model discloses the technique can avoid the harmful effects that high temperature environment brought.

Drawings

FIG. 1 is a schematic diagram of a C-EPS system of the column electric power steering system;

FIG. 2 is a schematic view of an electric assist unit;

FIG. 3 is a schematic view of a worm gear;

FIG. 4 is a schematic cross-sectional view of a worm gear reduction mechanism with a fixed center distance structure;

FIG. 5 is a schematic diagram of a transverse section of a worm and gear speed reducing mechanism with an adjustable center distance structure;

FIG. 6 is a schematic longitudinal sectional view of a worm and gear speed reducing mechanism with an adjustable center distance structure;

FIG. 7 is a schematic cross-sectional view of a center-distance adjustable worm assembly;

fig. 8 is a schematic cross-sectional view of a center-distance adjustable structure centering assembly.

In the figure: 1 is a speed reducing mechanism; 2 is a worm gear; 3 is a worm; 4 is a reduction box body; 5 is a worm gear shaft assembly; 6 is a worm assembly; 7 is a worm wheel shaft; 8 is a ball bearing A; 9 is a ball bearing B; 10 is a rocking bearing; 11 is a limit clamp spring; 12 is a centering assembly; 13 is an O-ring; 14 is a cushion ring; 15 is a ball bearing C; 16 is a bearing bush; 17 is a bushing holder; 18 is a spring; and 19 is a housing.

Detailed Description

Example 1

The technical solution of the utility model is that adopt the worm gear structure (fig. 5, 6) of an adjustable centre-to-centre spacing formula in EPS reduction gears, reduction gears 1 contains reduction gears 4 and installs worm-gear shaft subassembly 5 and worm subassembly 6 in reduction gears 4 and intermeshing, worm-gear shaft subassembly 5 contains worm wheel 2, worm-gear shaft 7, ball bearing A8, ball bearing B9, and wherein ball bearing A8, worm wheel 2, ball bearing B9 are fixed in worm-gear shaft 7 through interference fit from top to bottom in proper order on, and worm-gear shaft subassembly 5 is fixed in reduction gears 4 through upper and lower ball bearing.

The worm assembly 6 (fig. 7) comprises a worm 3, a swing bearing 10, a limiting snap spring 11, a centering assembly 12, an O-ring 13 and a damping washer 14, wherein the swing bearing 10 is fixed at one end of the worm 3 through the limiting snap spring 11, the centering assembly 12 is fixed at the other end of the worm 3, and a radial floating gap is formed through the O-ring 13 between the centering assembly 12 and the worm 3.

The aligning assembly 12 (fig. 8) comprises a ball bearing C15, a bearing bush 16, a bush support 17, a spring 18 and a shell 19, wherein the ball bearing C15 and the bearing bush 16 are positioned at one end of the shell, the bearing bush 16, the bush support 17 and the spring 19 are positioned at the other end of the shell, the bush support 17 is radially designed into a cylindrical boss, the distance between the bottom surface of the boss of the bush support 17 and the inner wall of the shell is smaller than the free length of the spring 18, and the spring 18 can form continuous radial pressure after the spring 18 is arranged in the bush support 17.

In the above technical solution, the worm wheel shaft assembly 5 is completely constrained in the radial direction, the centering assembly 12 at one end of the worm assembly 6 and the worm 3 have a certain floating gap, and the oscillating bearing 10 at the other end enables the worm 3 to have a certain oscillating degree of freedom, so that the meshing position of the worm 3 and the worm wheel 2 has a certain radial degree of freedom, and the worm 3 tends to be continuously close to the worm wheel 2 by the continuous radial pressure generated by the spring 18 in the centering assembly 12 in a compressed state. When the worm wheel 2 and the worm 3 generate clearance due to friction or reduction of ambient temperature, the center distance of the worm 3 is reduced by approaching the worm wheel 2 under the action of radial pressure of the spring 18, so that the clearance compensation effect is achieved; when the environmental temperature rises, because the meshing position of the worm 3 and the worm wheel 2 has certain radial freedom degree, the worm 3 retreats relative to the worm wheel 2 along the radial direction due to the expansion of materials, and because the deformation of the spring 18 is small, the meshing friction force of the worm wheel 2 and the worm 3 is almost not changed, thereby ensuring the stability of the steering performance.

In addition to the above embodiments, the present invention may have other embodiments. All the technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope claimed by the present invention.

Claims

1. An automobile electric steering system with a built-in self-adjusting gap structure is characterized in that: mainly adopts a center distance adjustable worm and gear structure in an EPS speed reducing mechanism, wherein the speed reducing mechanism comprises a speed reducing box body, and a worm and gear shaft assembly and a worm assembly which are arranged in the speed reducing box body and are mutually meshed; wherein the worm gear shaft component is fixed, and the worm component is adjustable in radial direction;

the worm wheel shaft assembly comprises a worm wheel, a worm wheel shaft, a ball bearing A and a ball bearing B, wherein the ball bearing A, the worm wheel and the ball bearing B are fixed on the worm wheel shaft in an interference fit manner from top to bottom in sequence, and the worm wheel shaft assembly is fixed in the reduction box body through the ball bearing A and the ball bearing B;

the aligning component comprises a ball bearing C, a bearing bush, a bush support, a spring and a shell, the ball bearing C and the bearing bush are located at one end of the shell, the bush support and the spring are located at the other end of the shell, the bush support is a cylindrical boss along the radial direction, the distance between the bottom surface of the boss support and the inner wall of the shell is smaller than the free length of the spring after the bearing bush, the bush support and the spring are assembled in place, and the spring is subjected to energy storage deformation to form continuous radial pressure.

2. The automotive electric power steering system with a built-in self-aligning structure according to claim 1, characterized in that: the worm wheel shaft assembly is radially constrained in the reduction box body; the aligning component and the worm of worm subassembly one end have certain clearance of floating, and the oscillating bearing of the worm subassembly other end makes the worm possess certain swing degree of freedom, and there is certain radial degree of freedom in the meshing position of worm and worm wheel this moment, and the continuous radial pressure that is in compression state's spring production in the aligning component makes the worm produce the trend that constantly is close to the worm wheel.

3. The automotive electric power steering system with a built-in self-aligning structure according to claim 1, characterized in that: when the worm wheel and the worm generate a gap due to friction or reduction of ambient temperature, the worm approaches the worm wheel under the action of radial pressure of a spring in the aligning component to reduce the center distance; when the environmental temperature rises, the worm retracts relative to the worm wheel along the radial direction due to the fact that a certain radial degree of freedom exists in the meshing position of the worm and the worm wheel due to material expansion, and the meshing friction force of the worm and the worm is almost unchanged due to the fact that the deformation amount of the spring is small.

4. The automotive electric power steering system with a built-in self-aligning structure according to claim 1, characterized in that: a certain floating clearance is formed between the worm and the aligning component through an O-shaped ring.