CN114060478B

CN114060478B - Transmissions and motor vehicles

Info

Publication number: CN114060478B
Application number: CN202010781275.9A
Authority: CN
Inventors: 陈苏涛; 池建辉
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2020-08-06
Filing date: 2020-08-06
Publication date: 2025-09-12
Anticipated expiration: 2040-08-06
Also published as: CN114060478A

Abstract

The present invention relates to a gearbox and a motor vehicle. The gearbox includes a housing, a planetary gear set, and a retaining ring. The planetary gear set includes a ring gear mounted within the housing. The inner surface of the housing has an axial section and a first radial section, the first radial section extending radially inward from one end of the axial section. The ring gear is mounted radially inward of the axial section, such that the outer peripheral surface of the ring gear faces the axial section, and the first axial end face of the ring gear faces and is capable of abutting the first radial section. The housing has a first annular groove formed on the axial section, and the ring gear has a second annular groove formed on its outer peripheral surface. The first annular groove and the second annular groove are axially aligned. The retaining ring is mounted between the first annular groove and the second annular groove, thereby constraining the axial position of the ring gear relative to the housing. The gearbox and motor vehicle of the present invention have a compact structure and high installation stability.

Description

Gearbox and motor vehicle

Technical Field

The invention relates to the technical field of vehicles. In particular, the invention relates to a gearbox for a motor vehicle and a motor vehicle comprising such a gearbox.

Background

Gearboxes are an important component in the drive train of motor vehicles. The driving force from the engine is passed through a series of gears in a gearbox to achieve the desired torque, rotational speed, steering etc. parameters and then transferred to the wheels. For most motor vehicles, particularly gearboxes for electric vehicles, it is an important function to reduce and increase the output torque of the engine. In order to obtain a large gear ratio in a limited space in a gearbox to achieve a reduction and an increase in torque, a planetary gear set is usually provided in the gearbox. The planetary gear is generally composed of sun gear, planet gears, planet carrier, and ring gear. Wherein the ring gear in the gearbox is typically located radially outside the sun gear and the planet gears and fixed into the housing of the gearbox.

For example, US 8216107 B2 discloses a typical ring gear mounting. In such a conventional mounting manner, both axial ends of the ring gear are restrained axially by a stepped portion and a snap ring on the transmission case, respectively. Such a snap ring is usually mounted in a ring groove of the gearbox housing and abuts an axial end face of the ring gear. Thus, in conventional designs, the snap ring is typically located axially outward of the ring gear. This means that the axial length of the housing section to which the ring gear is attached needs to be lengthened to form a ring groove of the stationary snap ring.

Furthermore, in conventional designs, the groove bottom in which the snap ring is mounted presents a flat surface in cross section, the snap ring is no longer radially compressed after assembly into the groove, thus maintaining a constant size. In other words, a loose fit is now presented between the snap ring and the housing. Because an axial gap exists between the clamping ring and the shell, the gear ring can axially move under the action of external force. This can adversely affect the NVH (noise, vibration and harshness) performance of the vehicle.

Disclosure of Invention

The technical problem to be solved by the invention is therefore to provide a gearbox and a motor vehicle which are compact and have high installation stability.

The above technical problem is solved by a gearbox according to the present invention. The gearbox comprises a shell, a planetary gear set and a clamping ring, wherein the planetary gear set comprises a gear ring and other components arranged in the shell. The inner surface of the housing has an annular axial section and a first radial section extending from one end of the axial section toward the radially inner side. The ring gear is mounted radially inward of the axial section of the housing such that an outer peripheral surface of the ring gear faces the axial section of the housing, and one axial end surface (which may be referred to as a first axial end surface) of the ring gear faces and is capable of abutting against the first radial section of the housing. The housing has a first annular groove formed on an axial section thereof, and the ring gear has a second annular groove formed on an outer peripheral surface thereof, the first annular groove of the housing being axially aligned with the second annular groove of the ring gear, the snap ring being mounted between the first annular groove and the second annular groove and substantially encircling the ring gear, thereby constraining the axial position of the ring gear relative to the housing.

In order to facilitate the assembly of the ring gear in the housing, the ring gear can be limited in one axial direction by abutting against a first radial section of the housing, and in the opposite axial direction by mounting a snap ring. In contrast to prior art solutions in which the snap ring is mounted outside the end face of the ring gear, the gearbox according to the invention shifts the mounting position of the snap ring between the housing and the ring groove of the ring gear, while the second ring groove on the ring gear is formed on the outer circumferential surface of the ring gear. That is, the snap ring is mounted at the axial middle of the ring gear rather than outside the end face of the ring gear. Therefore, the snap ring does not need to occupy additional axial space outside the gear ring, so that the structure of the housing can be more compact. Meanwhile, as the clamping ring is arranged between the two annular grooves, the clamping ring is more stable in constraint of the axial position of the gear ring relative to the shell. In this case, the inner surface of the housing may also have a second radial section extending radially outward from the other end of the axial section, and the second radial section may be flush with the second axial end face of the ring gear (i.e., the other axial end face opposite to the first axial end face). Since the first radial section and the second radial section at both ends of the axial section together define the axial extension of the axial section, this means that the axial extension of the axial section is significantly shortened compared to the prior art.

According to a preferred embodiment of the invention, the snap ring can be clamped radially inwards by elastic deformation. For example, the snap ring may be a metal ring having a notch in the circumferential direction. Therefore, the snap ring can be easily fitted into the ring groove by elastic deformation of the snap ring.

According to another preferred embodiment of the present invention, the snap ring and the first ring groove may be clearance-fitted in the axial direction, thereby facilitating the mounting of the snap ring into the first ring groove. At the same time, this also means that the snap ring can move axially in the first ring groove. For this purpose, it is further preferred that the first annular groove, as seen in a section through the axis, has a bottom surface which is inclined with respect to the axial direction such that the radius of the annular bottom surface decreases gradually towards the first radial section. The snap ring is thus elastically deformed radially inwards when moving towards the first radial section, thereby further clamping the ring gear to cushion the axial impact force of the ring gear on the first radial section of the housing.

According to another preferred embodiment of the invention, the second ring groove on the ring gear may have an axial length smaller than the axial length of the first ring groove on the housing, such that no significant axial movement of the snap ring in the second ring groove occurs, thereby facilitating restraining and dampening of the axial movement of the ring gear by the sloped bottom surface of the first ring groove.

According to another preferred embodiment of the invention, the second ring groove may be located at the axial midpoint of the ring gear, so that correspondingly the snap ring is also located at the axial midpoint of the ring gear.

According to a further preferred embodiment of the invention, the axial section of the housing and the peripheral surface of the ring gear may each have mutually cooperating splines, the housing and the ring gear being torsionally connected by means of the splines, whereby circumferential restraint of the ring gear is achieved.

The above-mentioned technical problem is also solved by a motor vehicle according to the invention, which comprises a gearbox having the above-mentioned features.

Drawings

The invention is further described below with reference to the accompanying drawings. Like reference numerals in the drawings denote functionally identical elements. Wherein:

FIG. 1 illustrates a perspective view of a transmission according to an embodiment of the present invention;

FIG. 2 shows an exploded view of a transmission according to an embodiment of the invention;

FIG. 3 illustrates a front view of a transmission according to an embodiment of the present invention;

FIG. 4 shows a cross-sectional view of a transmission according to an embodiment of the invention, and

Fig. 5 shows a partial enlarged view of a section of the gearbox of fig. 4.

Detailed Description

Specific embodiments of a transmission and a motor vehicle according to the present invention will be described below with reference to the accompanying drawings. The following detailed description and the accompanying drawings are provided to illustrate the principles of the invention and not to limit the invention to the preferred embodiments described, the scope of which is defined by the claims.

According to a preferred embodiment of the present invention, a gearbox for a motor vehicle is provided. Fig. 1 to 4 show a perspective view, an exploded view, a front view and a cross-sectional view, respectively, of a transmission according to this embodiment. As shown, the transmission includes a housing 10 and various components such as a planetary gear set mounted within the housing 10. The planetary gear sets may be conventional assemblies that include sun gears, planet carrier, and ring gear 20. For the sake of simplicity in explaining the technical solution of the present invention, only the ring gear 20 is shown in the drawings, while other components are omitted. Those skilled in the art will appreciate that various other components may be additionally mounted in the transmission as desired.

As shown in fig. 1 and 2, the interior of the housing 10 has a cavity, a portion of which is generally cylindrical. The sides of this cylindrical cavity portion are constituted by axial sections 11 of the inner surface of the housing 10. The inner surface of the housing 10 also has two substantially radially extending sections, namely a first radial section 12 and a second radial section 13. As shown in fig. 4, the first radial section 12 is connected to an end of the axial section 11 remote from the open end (right end in fig. 4) of the housing 10, and extends radially inward from the end of the axial section 11. The second radial section 13 is connected to the other end of the axial section 11 (i.e., the end near the open end of the housing 10) and extends radially outward from the end of the axial section 11. The housing 10 has a plurality of axially extending splines 15 formed on the axial section 11. Thus, the axial section 11 is not a smooth surface, as seen in a section perpendicular to the axis, but a serrated surface.

As shown in fig. 2, the ring gear 20 is annular in shape as a whole. The ring gear 20 has an outer peripheral surface 21, and a plurality of axially extending splines 23 are also formed on the outer peripheral surface 21. Thus, the peripheral surface 21 is also a zigzag surface as viewed in a section perpendicular to the axis. The ring gear 20 is mounted radially inside the axial section 11 in the housing 10 such that the outer circumferential surface 21 of the ring gear 20 faces the axial section 11 of the housing 10, while the first axial end face of the ring gear 20 faces the first radial section 12 of the housing 10, and the second axial end face opposite to the first axial end face faces away from the first radial section 12 of the housing 10. As shown in fig. 1 and 3, when the ring gear 20 is mounted in the housing 10, the spline 15 of the housing 10 and the spline 23 of the ring gear 20 are engaged with each other in the circumferential direction, thereby connecting the ring gear 20 with the housing 10 in torsion.

As shown in fig. 2 and 4, a first ring groove 14 is formed in an axial middle portion of the axial section 11 of the housing 10, and a second ring groove 22 is formed correspondingly in an axial middle portion of the outer peripheral surface 21 of the ring gear 20. The snap ring 30 is a circular metal ring having a notch in the circumferential direction, and thus the size of the radius can be changed by elastic deformation. By elastically deforming the snap ring 30, the snap ring 30 can be mounted to the radially outer side of the ring gear 20 so as to surround the ring gear 20 in the circumferential direction. When the ring gear 20 is mounted in the housing 10, the first ring groove 14 and the second ring groove 22 are substantially aligned in the axial direction, and the snap ring 30 is engaged between the first ring groove 14 of the housing 10 and the second ring groove 22 of the ring gear 20 in the radial direction. At the same time, the first axial end face of the ring gear 20 can abut in the axial direction against the first radial section 12 of the housing 10. Thus, the ring gear 20 is constrained by the position of the first radial segment 12 in the axial direction towards the first radial segment 12, and by the position of the snap ring 30 in the axial direction away from the first radial segment 12.

Preferably, the second ring groove 22 may be located at an axial midpoint of the ring gear 20, which is also an axial midpoint of the outer peripheral surface 21. Furthermore, the axial length of the ring gear 20 may be substantially equal to the axial length of the axial section 11 of the housing 10, such that when the ring gear 20 is installed into the housing 10, the second axial end surface of the ring gear 20 is substantially flush with the second radial section 13 of the housing 10. This results in a significantly shorter axial length of the axial section 11 of the housing 10 compared to the prior art, thereby increasing the compactness of the construction.

Fig. 5 shows a partial detail of the section in fig. 4. As shown in fig. 5, the axial length of the first ring groove 14 of the housing 10 is greater than the axial length of the second ring groove 22 of the ring gear 20. The snap ring 30 is a clearance fit with the first ring groove 14 in the axial direction for ease of assembly so that slight axial movement of the snap ring 30 relative to the housing 10 is possible. Accordingly, the ring gear 20 can also be moved slightly axially relative to the housing 10 until the first axial end face of the ring gear 20 abuts one end against the first radial section 12 of the housing 10, or until the second ring groove 22 abuts the snap ring 30 toward the other end and the snap ring 30 abuts the first ring groove 14 in the same direction.

The base surface of the first ring groove 14 is inclined with respect to the axial direction, as seen in a section through the axis, such that the radius of the annular base surface gradually decreases toward the first radial section 12. When the snap ring 30 is located at an end of the first ring groove 14 remote from the first radial section 12, there may be a tight fit or a loose fit between the snap ring 30 and the outer circumferential surface 21 of the ring gear 20 in the radial direction, but during axial movement of the ring gear 20 toward the first radial section 12, the snap ring 30 will also move axially toward the first radial section 12, while the sloped bottom surface of the first ring groove 14 causes the snap ring 30 to elastically deform radially inward to progressively grip the ring gear 20. Thus, the closer the ring gear 20 is to the first radial section 12, the more resistance is received, and thus the speed at which the ring gear 20 moves toward the first radial section 12 can be reduced, thereby cushioning the impact between the ring gear 20 when it abuts against the first radial section 12. In this way, the gearbox reduces wear on the housing and the ring gear, thereby extending the service life.

According to another embodiment of the invention, there is also provided a motor vehicle comprising a gearbox according to the previous embodiment, and accordingly having all the features and advantages of the gearbox.

While possible embodiments are exemplarily described in the above description, it should be understood that there are numerous variations of the embodiments still through all known and furthermore easily conceivable combinations of technical features and embodiments by the skilled person. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. The technical teaching for converting at least one exemplary embodiment is provided more in the foregoing description to the skilled person, wherein various changes may be made without departing from the scope of the claims, in particular with regard to the function and structure of the components.

Reference numeral table

10. Shell body

11. Axial section

12. A first radial section

13. A second radial section

14. First ring groove

15. Spline

20. Gear ring

21. Peripheral surface

22. Second ring groove

23. Spline

30. Clasp ring

Claims

1. A gearbox, comprising a housing (10), a planetary gear set and a snap ring (30), wherein the planetary gear set comprises a ring gear (20) mounted in the housing (10), the inner surface of the housing (10) comprising an axial section (11) and a first radial section (12), the first radial section (12) extending radially inward from one end of the axial section (11), the ring gear (20) being mounted radially inward of the axial section (11), such that an outer peripheral surface (21) of the ring gear (20) faces the axial section (11), and a first axial end surface of the ring gear (20) faces and is capable of abutting against the first radial section (12),

It is characterized in that

The housing (10) has a first annular groove (14) formed on the axial section (11), and the gear ring (20) has a second annular groove (22) formed on the outer peripheral surface (21), the first annular groove (14) and the second annular groove (22) are aligned in the axial direction, and the snap ring (30) is installed between the first annular groove (14) and the second annular groove (22), thereby constraining the axial position of the gear ring (20) relative to the housing (10); the snap ring (30) can be clamped toward the radial inside by elastic deformation; the snap ring (30) and the first annular groove (14) are clearance-fitted in the axial direction; when observed in a cross-section through the axis, the first annular groove (14) has a bottom surface inclined with respect to the axial direction, and the radius of the bottom surface gradually decreases toward the first radial section (12), so that the snap ring (30) elastically deforms toward the radial inside when moving toward the first radial section (12).

2. The gearbox according to claim 1, characterized in that an axial length of the second annular groove (22) is smaller than an axial length of the first annular groove (14).

3. The gearbox according to claim 1, characterized in that the snap ring (30) is a metal ring having a gap in the circumferential direction.

4. The gearbox according to claim 1, characterized in that the second annular groove (22) is located at the axial midpoint of the ring gear (20).

5. The gearbox according to claim 1, characterized in that the inner surface of the housing (10) further has a second radial section (13), the second radial section (13) extending radially outward from the other end of the axial section (11), and the second radial section (13) is flush with the second axial end surface of the ring gear (20).

6. The gearbox according to any one of claims 1 to 5, characterized in that the axial section (11) and the outer peripheral surface (21) respectively have splines (15, 23) that cooperate with each other, and the housing (10) and the ring gear (20) are torsionally connected via the splines (15, 23).

7. A motor vehicle, characterized in that it comprises a gearbox according to any one of claims 1 to 6.