CN216611341U

CN216611341U - Speed reduction mechanism and electric power steering system

Info

Publication number: CN216611341U
Application number: CN202122935700.8U
Authority: CN
Inventors: 皮儿·龙格; 夏龙祥
Original assignee: Nexteer Automotive Suzhou Co Ltd
Current assignee: Nexteer Automotive Suzhou Co Ltd
Priority date: 2021-11-26
Filing date: 2021-11-26
Publication date: 2022-05-27
Anticipated expiration: 2031-11-26

Abstract

The utility model relates to the technical field of automobile steering, and provides a speed reducing mechanism and an electric power steering system. The speed reducing mechanism is applied to an electric power steering system and comprises: the worm wheel and the worm which are meshed with each other are accommodated in the shell, the end face of the worm wheel output side of the shell is provided with an annular flange which extends axially, and the output shaft of the worm wheel extends out of the annular flange; a single bearing sleeved on the output shaft and at least partially accommodated in the annular flange, the bearing having an output side end face away from the worm wheel; and the mounting bracket comprises a connecting part with a through hole, and the connecting part is fixed on the end surface of the annular flange and presses against the end surface of the output side of the outer ring of the bearing. The utility model realizes the compact structure of the speed reducing structure through a single bearing, the end surface of the bearing, especially the end surface of the output side of the outer ring can be stably supported, and the single bearing has high structural universality and can be suitable for the speed reducing mechanisms of various electric power steering systems.

Description

Speed reduction mechanism and electric power steering system

Technical Field

The utility model relates to the technical field of automobile steering, in particular to a speed reducing mechanism and an electric power steering system.

Background

An Electric Power Steering (EPS) system provides an auxiliary torque through a Power-assisted motor, and a speed reduction mechanism reduces the speed and increases the torque of the output of the Power-assisted motor to realize Steering assistance.

Specifically, the speed reduction mechanism mainly includes a worm wheel and a worm that mesh with each other. The input shaft of the worm wheel receives the steering torque from the steering input shaft, the power-assisted motor generates the power-assisted torque according to the steering torque, and the power-assisted torque is transmitted to the steering output shaft through the output shaft of the worm wheel after being subjected to deceleration and amplification by the worm wheel and the worm, so that the steering power is realized.

Fig. 1 shows a partial sectional structure of a conventional reduction mechanism, and as shown in fig. 1, a worm gear is housed in a housing, and a rolling bearing 130 is provided between an output shaft 110 of the worm gear and an end face flange 120 of the housing. In the prior art design, the rolling bearing 130 is generally provided in two, with the following drawbacks:

1) the end face flange 120 needs to be set to a high height to accommodate the rolling bearing 130, so that the overall structure of the reduction mechanism cannot be compact;

2) the end face of the rolling bearing 130, particularly the output side end face 130' of the outer ring, cannot be stably supported.

It is to be noted that the information applied in the above background section is only for enhancing the understanding of the background of the present invention, and thus may include information that does not constitute prior art known to those of ordinary skill in the art.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention provides a reduction mechanism and an electric power steering system, in which a reduction structure is compact by a single bearing, an end surface of the bearing, particularly, an output side end surface of an outer ring can be stably supported, and the single bearing has high structural versatility and can be applied to reduction mechanisms of various electric power steering systems.

According to an aspect of the present invention, there is provided a speed reduction mechanism applied to an electric power steering system, including: the worm wheel and the worm which are meshed with each other are accommodated in the shell, the end face of the worm wheel output side of the shell is provided with an annular flange which extends axially, and the output shaft of the worm wheel extends out of the annular flange; a single bearing sleeved on the output shaft and at least partially accommodated in the annular flange, the bearing having an output side end face away from the worm wheel; and the mounting bracket comprises a connecting part with a through hole, and the connecting part is fixed on the end surface of the annular flange and presses against the end surface of the output side of the outer ring of the bearing.

In some embodiments, the bearing partially protrudes beyond the annular flange; the end face of the through hole is provided with a first convex shoulder extending in the radial direction, the extending part of the bearing is accommodated in the through hole, and the output side end face of the outer ring of the bearing is pressed against the first convex shoulder.

In some embodiments, the bearing is entirely housed in the annular flange; and the output side end surface of the outer ring of the bearing is pressed against the end surface of the through hole.

In some embodiments, the outer wall of the output shaft is screwed with a nut, and the output side end face of the inner ring of the bearing is pressed against the nut; or the outer wall of the output shaft is provided with a deformation protruding part, and the output side end face of the inner ring of the bearing is pressed against the deformation protruding part.

In some embodiments, the bearing has a drive side end face proximate the worm gear; the inner wall of the annular flange is provided with a second convex shoulder extending in the radial direction, the outer wall of the output shaft is provided with a third convex shoulder extending in the radial direction, the driving side end face of the outer ring of the bearing is pressed against the second convex shoulder, and the driving side end face of the inner ring of the bearing is pressed against the third convex shoulder.

In some embodiments, the bearing is a four-point contact ball bearing.

In some embodiments, an outer edge of the connecting portion is fixed to an end face of the annular flange by a plurality of bolts; the mounting bracket further comprises a bracket part integrally connected with the connecting part, and the bracket part is used for mounting the speed reducing mechanism to the automobile beam.

In some embodiments, the mounting bracket is cast or stamped.

In some embodiments, the housing includes a worm wheel cavity and a worm cavity, which are communicated with each other, the worm wheel cavity is used for accommodating the worm wheel, the worm cavity is used for accommodating the worm, and the worm cavity is integrally connected with the worm wheel cavity.

According to another aspect of the present invention, there is provided an electric power steering system including the speed reduction mechanism according to any of the above embodiments.

Compared with the prior art, the utility model has the beneficial effects that:

the structure of the speed reducing structure is compact through a single bearing, the end face of the bearing, particularly the end face of the output side of the outer ring can be stably supported, the structural universality of the single bearing is high, and the single bearing can be suitable for speed reducing mechanisms of various electric power steering systems.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the utility model, as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the utility model and together with the description, serve to explain the principles of the utility model. It is obvious that the drawings in the following description are only some embodiments of the utility model, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 is a partial cross-sectional view schematically showing a conventional reduction mechanism;

fig. 2 is a schematic perspective view showing a reduction mechanism according to an embodiment of the present invention;

fig. 3 is a schematic view showing a partial cross-sectional structure of the speed reducing mechanism shown in fig. 2;

fig. 4 is a schematic perspective view showing a reduction mechanism according to still another embodiment of the present invention;

fig. 5 is a partial cross-sectional view schematically showing the reduction mechanism shown in fig. 4.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their repetitive description will be omitted.

Furthermore, the use of "first," "second," and similar terms in the detailed description are not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. It should be noted that features of the embodiments of the utility model and of the different embodiments may be combined with each other without conflict.

The speed reducing mechanism is applied to an Electric Power Steering System, in particular to a Column-assisted Electric Power Steering System (CEPS for short).

Fig. 2 shows a perspective structure of a speed reducing mechanism in one embodiment, and fig. 3 shows a partial sectional structure of the speed reducing mechanism shown in fig. 2; fig. 4 shows a perspective structure of a speed reducing mechanism in a further embodiment, and fig. 5 shows a partial sectional structure of the speed reducing mechanism shown in fig. 4. As shown in fig. 2 to 5, the reduction mechanism of the present invention includes:

a worm wheel and a worm (not specifically shown) which are engaged with each other are accommodated in the housing 20, a worm wheel output side end face 20a of the housing 20 is provided with an annular flange 30 extending in the axial direction (extending along the Y axis), and an output shaft 40 of the worm wheel protrudes from the annular flange 30.

The "output side" in the embodiment of the present invention refers to a side to which a steering output shaft of an electric power steering system is connected, and is a lower side in the perspective of fig. 3 and 5; the "driving side" is a side to which a steering input shaft of the electric power steering system is connected, and is an upper side in the perspective of fig. 3 and 5. Further, fig. 3 and 5 are sectional views along the central axis of the output shaft 40 of the worm wheel, respectively.

A single bearing 50 is mounted on the output shaft 40 and is at least partially received in the annular flange 30, the bearing 50 having an output side end face distal from the worm wheel, i.e., a lower end face, in the perspective of fig. 3 and 5.

The mounting bracket 60 includes a connecting portion 61 having a through hole, and the connecting portion 61 is fixed to an end surface of the annular flange 30 and is pressed against an output side end surface of the outer ring 51 of the bearing 50, i.e., a lower end surface of the outer ring 51.

Fig. 3 shows a structure in which the bearing 50 partially protrudes from the annular flange 30, and referring to fig. 3, an end surface of the through hole of the connecting portion 61 is provided with a first shoulder 611 extending radially (extending along the X axis), the protruding portion of the bearing 50 is received in the through hole of the connecting portion 61, and an output-side end surface of the outer ring 51 of the bearing 50 is pressed against the first shoulder 611.

Fig. 5 shows a structure in which the bearing 50 is entirely accommodated in the annular flange 30, and referring to fig. 5, an output-side end face of the outer ring 51 of the bearing 50 is pressed against an end face of the through hole of the connecting portion 61.

Therefore, the output-side end surface of the outer ring 51 of the bearing 50 can be stably supported by the connecting portion 61 of the mounting bracket 60.

Further, in one embodiment, as shown in fig. 2 to 5, a nut 41 is screwed to an outer wall of the output shaft 40 of the worm wheel, and an output side end surface of the inner ring 52 of the bearing 50 (i.e., a lower end surface of the inner ring 52) is pressed against the nut 41.

Alternatively, in other embodiments, the outer wall of the output shaft 40 of the worm wheel may be provided with a deformed protrusion against which the output-side end face of the inner ring 52 of the bearing 50 may be pressed.

Therefore, the output-side end surface of the inner race 52 of the bearing 50 can be stably supported by the outer wall structure design of the output shaft 40 of the worm wheel.

As shown in continued reference to fig. 2-5, the bearing 50 also has a drive side end face adjacent the worm gear, i.e., an upper end face, in the perspective of fig. 3 and 5. The inner wall of the annular flange 30 is provided with a radially extending second shoulder 32, the outer wall of the output shaft 40 is provided with a radially extending third shoulder 43, the drive side end face of the outer ring 51 of the bearing 50 is pressed against the second shoulder 32, and the drive side end face of the inner ring 52 of the bearing 50 is pressed against the third shoulder 43.

Accordingly, the drive-side end surfaces of the outer ring 51 and the inner ring 52 of the bearing 50 can be stably supported by the inner wall of the annular flange 30 and the shoulder design of the output shaft 40 of the worm wheel.

In each of the above embodiments, the bearing 50 may specifically be a four-point contact ball bearing. Of course, the bearing 50 may take other forms depending on the design requirements.

Further, as shown in fig. 2 to 5 in combination, in one embodiment, the outer edge of the connecting portion 61 of the mounting bracket 60 is fixed to the end surface of the annular flange 30 by a plurality of bolts 610. The number of bolts 610 may be set as desired, and the outer edge of the connecting portion 61 shown in fig. 2 forms three flange portions extending outward so as to be fixed to the end surface of the annular flange 30 by the three bolts 610; the outer edge of the attachment portion 61 is shown in fig. 4 as forming four outwardly extending flange portions for attachment to the end face of the annular flange 30 by four bolts 610. The mounting bracket 60 further includes a bracket portion 62 integrally connected to the connecting portion 61, the bracket portion 62 being used for mounting the reduction mechanism to the cross member of the vehicle.

The mounting bracket 60 may be cast or stamped. The mounting bracket 60 shown in fig. 2 is cast, and the mounting bracket 60 shown in fig. 4 is stamped and formed.

Further, in an embodiment, the housing 20 specifically includes a worm wheel cavity 21 and a worm cavity 22 that are communicated with each other, the worm wheel cavity 21 is used for accommodating a worm wheel, the worm cavity 22 is used for accommodating a worm, and the worm cavity 21 and the worm wheel cavity 22 are integrally connected.

An embodiment of the present invention further provides an electric power steering system, including the speed reduction mechanism described in any of the above embodiments. As can be seen in conjunction with fig. 2 and 4, the reduction mechanism is connected to the steering input shaft of the electric power steering system, which is connected to the steering wheel of the vehicle, through the input shaft 40' of the worm gear; the reduction mechanism is connected to a steering output shaft of the electric power steering system, which is connected to wheels of the vehicle, through an output shaft 40 of the worm wheel. The worm and the worm wheel of the speed reducing mechanism are meshed with each other, and the worm is connected with the power-assisted motor.

When the power steering is assisted, the input shaft 40' of the worm wheel receives the steering torque from the steering input shaft, the power motor generates the power steering torque according to the steering torque, and the power steering torque is reduced and amplified by the worm wheel and the worm and then transmitted to the power steering output shaft through the output shaft 40 of the worm wheel, so that the power steering is assisted.

In summary, the speed reducing mechanism and the electric power steering system of the utility model realize the compact structure of the speed reducing structure through a single bearing; the end face of the bearing, especially the end face of the output side of the outer ring can be stably supported; and the single bearing has high structural universality and can be suitable for the speed reducing mechanisms of various electric power steering systems.

The foregoing is a more detailed description of the utility model in connection with specific preferred embodiments and it is not intended that the utility model be limited to these specific details. For those skilled in the art to which the utility model pertains, several simple deductions or substitutions can be made without departing from the spirit of the utility model, and all shall be considered as belonging to the protection scope of the utility model.

Claims

1. A speed reduction mechanism applied to an electric power steering system is characterized by comprising:

the worm wheel and the worm which are meshed with each other are accommodated in the shell, the end face of the worm wheel output side of the shell is provided with an annular flange which extends axially, and the output shaft of the worm wheel extends out of the annular flange;

a single bearing sleeved on the output shaft and at least partially accommodated in the annular flange, the bearing having an output side end face away from the worm wheel;

and the mounting bracket comprises a connecting part with a through hole, and the connecting part is fixed on the end surface of the annular flange and presses against the end surface of the output side of the outer ring of the bearing.

2. A reduction mechanism according to claim 1, wherein said bearing partially protrudes from said annular flange;

the end face of the through hole is provided with a first convex shoulder extending in the radial direction, the extending part of the bearing is accommodated in the through hole, and the output side end face of the outer ring of the bearing is pressed against the first convex shoulder.

3. The reduction mechanism of claim 1, wherein the bearing is entirely received in the annular flange;

and the output side end surface of the outer ring of the bearing is pressed against the end surface of the through hole.

4. The reduction mechanism according to claim 1, wherein a nut is screwed to an outer wall of the output shaft, and an output-side end face of the inner race of the bearing is pressed against the nut; or

The outer wall of the output shaft is provided with a deformation protruding part, and the output side end face of the inner ring of the bearing is pressed against the deformation protruding part.

5. The reduction mechanism according to claim 1, wherein the bearing has a drive side end face close to the worm wheel;

the inner wall of the annular flange is provided with a second convex shoulder extending in the radial direction, the outer wall of the output shaft is provided with a third convex shoulder extending in the radial direction, the driving side end face of the outer ring of the bearing is pressed against the second convex shoulder, and the driving side end face of the inner ring of the bearing is pressed against the third convex shoulder.

6. The reduction mechanism according to claim 1, wherein the bearing is a four-point contact ball bearing.

7. The reduction mechanism according to claim 1, wherein an outer edge of the connecting portion is fixed to an end surface of the annular flange by a plurality of bolts;

the mounting bracket further comprises a bracket part integrally connected with the connecting part, and the bracket part is used for mounting the speed reducing mechanism to the automobile beam.

8. The retarding mechanism of claim 1, wherein the mounting bracket is cast or stamped.

9. The reduction mechanism according to claim 1, wherein the housing includes a worm wheel cavity and a worm cavity in communication with each other, the worm wheel cavity is configured to receive the worm wheel, the worm cavity is configured to receive the worm, and the worm cavity is integrally connected to the worm wheel cavity.

10. An electric power steering system characterized by comprising the speed reducing mechanism according to any one of claims 1 to 9.