CN118934937A - Bearing unit and gearbox - Google Patents

Abstract

The present invention relates to a bearing unit and a gearbox. The bearing unit includes: a bearing (30) for relatively rotatably supporting the shaft (10) and comprising an inner ring (31); pretensioning means (40) comprising a stop assembly (42) and an elastic member (41), the stop assembly (42) comprising at least two stop elements (421, 422) distributed in a circumferential direction, wherein the at least two stop elements (421, 422) are rotatable and/or translatable relative to each other at least in a plane perpendicular to the rotational axis of the bearing (30), and the at least two stop elements (421, 422) are axially fixably arranged at the shaft (10), the elastic member (41) being axially tensioned between the stop assembly (42) and the inner ring (31). The gearbox comprises a gearbox housing (20), a shaft element (10) and a bearing unit according to the above, wherein the shaft element (10) is mounted on the gearbox housing (20) in a relatively rotatable manner by means of the bearing unit.

Description

Bearing unit and gearbox

Technical Field

The invention relates to the technical field of bearings. The invention relates in particular to a bearing unit and a gearbox comprising such a bearing unit.

Background

In the case of hybrid-specific gearboxes, which are currently used in particular for hybrid vehicles, the input shaft is rotatably mounted on the gearbox housing by means of a double-row ball bearing. Specifically, the assembly of the double-row ball bearing 30 in the hybrid-specific gearbox can be as shown in fig. 1, the double-row ball bearing 30 being arranged in the annular space formed by the gearbox housing 20 and the input shaft 10, the positioning of the inner ring 31 of the double-row ball bearing 30 in the axial direction being effected by means of a special lock nut 60. Here, the lock nut 60 is screwed at the external thread portion of the outer peripheral surface of the input shaft 10 by the internal thread portion 61 of the radially inner side thereof. The sealing element 50 for sealing the double row ball bearing 30 is in this case arranged in the radial space between the gearbox housing 20 and the lock nut 60.

However, this double row ball bearing assembly scheme requires a special lock nut, and both the lock nut and the input shaft require threaded portions to be machined, which results in higher part costs. In addition, in this assembly, the radially inner side and the radially outer side of the lock nut each form a sealing region, and the risk of leakage increases correspondingly. In particular, since the outer circumferential surface of the union nut is used as a sealing surface, the sealing performance may be affected even if the concentricity tolerance of the radial shaft seal is correspondingly increased; on the contrary, if the sealing performance is to be ensured, the manufacturing accuracy of the lock nut and the input shaft needs to be increased, which in turn increases the cost of parts.

Disclosure of Invention

The object of the present invention is therefore to provide a bearing unit, in particular for gearboxes, which has both a low cost and good sealing properties.

According to one aspect of the invention, the above object is achieved by a bearing unit. The bearing unit comprises a bearing for rotatably supporting the shaft and comprising an inner ring, and a pretensioning mechanism comprising a stop assembly and an elastic member, wherein the stop assembly comprises at least two stop elements distributed in the circumferential direction, wherein the at least two stop elements can rotate and/or translate relative to each other at least in a plane perpendicular to the rotational axis of the bearing, and wherein the at least two stop elements can be arranged at least axially fixed at the shaft, and the elastic member is axially tensioned between the stop assembly and the inner ring.

Preferably, the bearing is a rolling bearing. The bearing may be implemented with reference to known designs. The bearing here comprises, in addition to the inner ring, other necessary components, such as an outer ring, rolling bodies and a cage, which are arranged coaxially to one another, the rolling bodies being arranged radially between the outer ring and the inner ring by means of the cage. Alternatively, the bearing is configured as a double row rolling bearing. Alternatively, the bearings are configured as single row rolling bearings. The shaft is rotatably supported by the housing via a bearing. The shaft is here, for example, a shaft in a device, for example in a gearbox, in particular in a hybrid-specific gearbox. The shaft element is for example an input shaft, an output shaft or an intermediate drive shaft arranged between the input shaft and the output shaft in the device. The housing is, for example, a device housing or a structure fixed relative to the device housing, for example, the housing may be a gearbox housing.

In the context of this document, unless otherwise indicated, all of "axial", "radial" and "circumferential" are based on the central axis of the bearing, i.e. the axis of rotation of the shaft, wherein "axial" is the direction parallel to or coincident with the central axis, and "radial" is the direction perpendicular to and intersecting the central axis, and "circumferential" is the direction surrounding the central axis.

Preferably, the pretensioning mechanism is arranged on one axial side of the bearing. The pretensioning mechanism includes a stop assembly and an elastic member. Within the scope of this document, the stop assembly is generally annular and comprises at least two stop elements distributed in the circumferential direction. Within the scope of this document, at least two stop elements of the stop assembly are arranged axially fixed on the shaft and do not limit the circumferential displaceability of the respective stop element relative to the shaft, i.e. the stop assembly is arranged at least axially fixed on the shaft. Advantageously, the stop assembly is arranged axially and circumferentially in a fixed manner relative to the shaft element. The elastic component is arranged axially between the individual stop elements of the stop assembly and the inner ring of the bearing and provides an axial preload. The stop assembly can be produced and arranged at the shaft element in a low-cost manner, avoiding the use of nuts and the machining of threads on the shaft element, and reducing the cost of parts. Furthermore, since the provision of the nut is avoided, the dynamic sealing of the bearing unit can be directly carried out at the outer circumferential surface of the shaft, avoiding the risk of the sealing member being sleeved radially outside the nut in order to reduce the axial dimension of the bearing unit as a whole, thereby increasing the number of sealing surfaces and increasing the insufficient concentricity of the shaft seal. At the same time, since at least two stop elements of the stop assembly can rotate and/or translate relative to each other in a plane perpendicular to the axis of rotation of the bearing, the setting on the shaft can be accomplished directly by means of the relative movement between these stop elements in the vicinity of the predetermined axial position, without having to first set the stop assembly on the free end of the shaft and then push the stop assembly axially up to the above-mentioned predetermined axial position, when the stop assembly is pushed, to avoid rubbing against the surface of the shaft which is to form a seal with the sealing member, and to avoid the addition of protective measures to the surface of the shaft during assembly to prevent the above-mentioned rubbing, thus ensuring both good sealing properties and fast implementation of the installation, saving assembly costs.

In a preferred embodiment, at least two stop elements are completely separated from one another. Whereby the stop assembly can be realized in a low cost manner. In this way, the individual stop elements in the stop assembly can be configured identically, so that further selection of a plurality of stop elements in the stop assembly during assembly can be avoided, and assembly effort can be saved.

In a preferred embodiment, adjacent two of the at least two stop elements are connected to each other by means of a flexible connecting member. The flexible connecting member is for example a hinge member. The flexible connection means can also be other connection means allowing relative rotation and/or relative translation between the stop elements. The stop component can be preassembled, parts are not easy to lose in the links of transportation and the like, and automation of the assembly process is facilitated.

In a preferred embodiment, the stop elements each have an arcuate shape. The overall annular structure of the stop assembly can thus be realized with a reduced number of parts, for example two, three, four or five, which is advantageous for reducing costs and simplifying assembly.

In a preferred embodiment, the stop element is configured with mating structures which can establish a form fit with structures at the outer circumferential surface of the shaft. Thereby, the stopper element can be easily mounted to the outer peripheral surface of the shaft.

In a preferred embodiment, the elastic member is configured as a belleville spring. The elastic member thus constructed is easy to manufacture and install, and the bearing unit can be implemented in a low-cost manner. Meanwhile, the disc spring has larger rigidity, can provide axial pretightening force which is suitable for most bearing requirements, and has high scheme universality degree.

In this case, the disk spring preferably rests with its radially inner end against the stop element of the stop assembly and with its radially outer end against the inner ring. The height of the projections of the individual stop elements relative to the outer circumferential surface of the shaft element can be low. Thus, the material can be saved and the cost can be reduced.

In a preferred embodiment, the bearing unit further comprises a sealing member, the pretensioning mechanism being arranged axially between the sealing member and the bearing. Preferably, the sealing member is configured as a sealing ring. Preferably, the sealing member is configured with at least one sealing lip radially inside. In this case, the pretensioning mechanism can assist in sealing while providing the pretensioning force. The stop assembly can thereby simultaneously stop the elastic member and simultaneously block the flow of lubricant, for example grease, in the bearing to the sealing region at the sealing lip, thereby enhancing the sealing effect.

In a preferred embodiment, the sealing member comprises a first sealing lip which can abut against the outer circumferential surface of the shaft and a second sealing lip which abuts against the axial end face of the stop element of the stop assembly. The first sealing lip can form a dynamic seal against the outer circumference of the shaft element as a main lip, whereby the dynamic seal can be applied directly to the shaft element, reducing the number of sealing surfaces and improving the concentricity of the shaft seal, thus improving the sealing performance. Meanwhile, the arrangement of the second sealing lip can further enhance the sealing effect of the sealing member.

According to another aspect of the invention, the above object is achieved by a gearbox. The gearbox comprises a gearbox housing, a shaft element and a bearing unit constructed according to the embodiment, wherein the shaft element is rotatably supported on the gearbox housing by means of the bearing unit. In this case, the transmission is preferably designed as a hybrid-specific transmission for a hybrid vehicle. Advantageously, the gearbox is provided with one, two or more than two bearing units as described above.

Drawings

Features, advantages, and technical effects of preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 shows a part of an axial section of a bearing unit according to the prior art.

Fig. 2 shows a part of an axial cross-section of a bearing unit according to a preferred embodiment.

Fig. 3 shows a perspective view of a stop assembly in a pretensioning mechanism of the bearing unit according to fig. 2.

Fig. 4 shows a part of a perspective view of the bearing unit according to fig. 2 during assembly of the stop assembly.

Fig. 5 shows a part of an axial section through the bearing unit according to fig. 2 during assembly of the stop assembly.

Detailed Description

Fig. 2 shows a bearing unit which is particularly suitable for gearboxes. The transmission is configured as a hybrid-specific transmission for a hybrid vehicle. Fig. 2 shows a gearbox housing 20 of the gearbox, an input shaft 10 and a bearing unit.

The bearing unit according to the present embodiment includes a bearing 30, a pretensioning mechanism 40, and a sealing member 50.

The bearing 30 is in this embodiment constructed as a double-row ball bearing. Here, the bearing 30 includes an inner ring 31, an outer ring, rolling elements, and a cage. The inner ring 30 comprises here two inner ring elements arranged axially side by side. The input shaft 10 is rotatably supported at the transmission housing 20 by means of bearings 30.

The pretensioning mechanism 40 is provided on one axial side of the bearing 30. The pretensioning mechanism 40 includes a stopper assembly 42 and an elastic member 41.

Fig. 3 shows a perspective view of the stopper assembly 42 in the pretensioning mechanism 40 according to the present embodiment. As shown in fig. 3, the stop assembly 42 comprises in this embodiment two stop elements 421, 422 completely separated from each other. The stop element 421 and the stop element 422 are each configured as a curved half-ring component. Referring to fig. 2 and 3, the stopper member 421 and the stopper member 422 are each mounted in the receiving groove 11 configured at the outer periphery of the input shaft 10.

As shown in fig. 2, the elastic member 41 configures a disc spring. The disk spring 41 bears with its radially inner ends against the stop assembly 42, i.e. the stop element 421 and the stop element 422, and with its radially outer ends against the inner ring 31 of the bearing 30, whereby an axial preload is provided by means of the disk spring 41.

According to the present embodiment, the assembling process of the pretensioning mechanism 40 on the input shaft 10 can be referred to fig. 4 and 5. Fig. 4 shows a partial view of the free end of the input shaft 10 in perspective view in the direction of the bearing 30, in which the stop assembly 42 is assembled; accordingly, fig. 5 shows the same process state as fig. 4 when the stop assembly 42 is assembled, with a partial view of the axial cross-section of the assembled input shaft 20 and bearing 30. As shown in fig. 4 and 5, when the disc spring 41 has been fitted onto the input shaft 20 and the disc spring 41 has been moved until it abuts against the axial end face of the inner race 31, an axial force F (indicated by arrows in fig. 4 and 5) is applied to the disc spring 41, at which time the disc spring 41 is compressed and the radially inner end of the disc spring 41 is at a slight axial distance from the notch edge of the accommodation groove 11 on the input shaft 10. In this case, the two stop elements 421, 422 are respectively snapped into the receiving groove 11 from diametrically opposite ends of the input shaft 10, so that the process state shown in fig. 4 and 5 is formed. As shown in particular in fig. 4, the point of application of the axial force F can be located exactly at the two gap positions of the two stop elements 421, 422 in the circumferential direction, whereby the axial force can be easily applied with the tool, avoiding interference between the tool and the part. When the axial force F is removed, the radially inner end of the belleville spring 41 abuts against the two stop elements 421, 422, thereby completing the assembly of the stop assembly 42.

It can thus be seen that the stop elements 421, 422 of the stop arrangement 42 and the disk spring 41 can be produced in a low-cost manner and that the installation of both at the input shaft 10 is easy to implement. Meanwhile, the disc spring 41 has high rigidity, can provide axial pretightening force which is suitable for most bearing requirements, and has high scheme universality. The solution of this embodiment avoids the use of nuts compared to the prior art solution illustrated by fig. 1, thereby eliminating the need to machine threads on the shaft and reducing the cost of the parts.

Returning to fig. 2, the sealing member 50 of the bearing unit is here arranged axially on the side of the pretensioning mechanism 40 remote from the bearing 30. The seal member 40 is configured as a seal ring and is configured with a seal lip 51 serving as a main lip on the radially inner side. The sealing lip 51 can abut against the outer peripheral surface of the input shaft 10, thereby forming a dynamic seal against the outer peripheral surface of the input shaft 10 when the gearbox is in operation.

Since the provision of the nut is avoided, the dynamic sealing of the bearing unit can be directly performed at the outer peripheral surface of the input shaft 10, avoiding the case where the sealing member is fitted radially outside the nut in order to reduce the axial dimension of the bearing unit as a whole, the number of sealing surfaces is reduced and concentricity of the shaft seal is improved as compared with the conventional scheme shown by fig. 1, thereby improving sealing performance. Furthermore, the stop elements 421, 422 in the prestressing mechanism 40 can simultaneously stop the disk spring 41 and simultaneously block the lubricant, for example grease, in the bearing 30 from flowing to the sealing contact region of the sealing lip 51 and the input shaft 10, as a result of which the sealing effect is also increased.

At the same time, since the two stop elements 421, 422 in the stop assembly 42 can rotate and/or translate relative to each other at least in a plane perpendicular to the axial direction of the bearing 30, when the stop assembly 42 is mounted to a predetermined axial position on the input shaft 10, i.e. the position of the receiving groove 11, the two stop members 421, 422 can be snapped directly into the receiving groove 11 from diametrically opposite sides, respectively, without having to first sleeve the stop assembly 42 onto the free end of the input shaft 10 and then axially push the stop assembly 42 up to the receiving groove 11, thereby avoiding scraping surfaces on the input shaft 10 that form a seal with the sealing member 50 when pushing the stop assembly 42, and avoiding adding additional protective measures to the input shaft surface during assembly to prevent such scraping, thus ensuring both good sealing performance and quick installation and assembly costs.

It is to be understood that the above examples of the present invention are provided for clarity of illustration only and are not limiting of the embodiments of the present invention. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

List of reference numerals

10. Shaft element

11. Accommodating groove

20. Shell body

30. Bearing

31. Inner ring

40. Pretension mechanism

41. Elastic member

42. Stop assembly

421. Stop element

422. Stop element

50. Sealing member

51. Sealing lip

60. Lock nut

61. Internal thread part

Claims (10)

1. Bearing unit, comprising:

A bearing (30) for supporting the shaft member (10) so as to be rotatable relative to each other and including an inner ring (31);

A pretensioning mechanism (40), comprising:

A stop assembly (42) which is ring-shaped as a whole and comprises at least two stop elements (421, 422) distributed in the circumferential direction, wherein the at least two stop elements (421, 422) can rotate and/or translate relative to each other at least in a plane perpendicular to the rotational axis of the bearing (30), and the at least two stop elements (421, 422) can be arranged at least axially fixedly at the shaft (10),

-An elastic member (41) axially tensioned between the stop assembly (42) and the inner ring (31).

2. Bearing unit according to claim 1, wherein the at least two stop elements (421, 422) are completely separated from each other.

3. Bearing unit according to claim 1, wherein adjacent two of the at least two stop elements are connected to each other by means of a flexible connection member.

4. Bearing unit according to claim 1, wherein the stop elements (421, 422) each have an arcuate overall structure.

5. Bearing unit according to claim 1, wherein the stop element (421, 422) is configured with a mating structure which can establish a form fit with a structure at the outer circumferential surface of the shaft (10).

6. Bearing unit according to claim 1, wherein the elastic member (41) is configured as a belleville spring.

7. Bearing unit according to claim 6, wherein the belleville spring abuts with its radially inner end against the at least two stop elements (421, 422) and with its radially outer end against the inner ring (31).

8. Bearing unit according to claim 1, wherein the bearing unit further comprises a sealing member (50), the pretensioning mechanism (40) being arranged axially between the sealing member (50) and the bearing (30).

9. Bearing unit according to claim 8, wherein the sealing member (50) comprises a first sealing lip (50) and a second sealing lip, wherein the first sealing lip (50) is capable of abutting against the outer circumferential surface of the shaft (10) and the second sealing lip abuts against the axial end faces of the at least two stop elements.

10. Gearbox comprising a gearbox housing (20), a shaft element (10) and a bearing unit according to any of claims 1 to 9, wherein the shaft element (10) is supported at the gearbox housing (20) by means of the bearing unit in a relatively rotatable manner.