DE102022201802A1 - Bearing arrangement of two shafts - Google Patents

Abstract

The invention relates to a bearing arrangement comprising a first shaft (1), a second shaft (2) and means for applying an axial force to at least one of the two shafts (1, 2), the first shaft (1) having a conical section on an outer peripheral surface (3) and external teeth (4), the second shaft (2) having a conical section (5) and internal teeth (6) on an inner peripheral surface, the two shafts (1, 2) being coaxial with one another and thus axially overlapping are arranged in such a way that the internal toothing (6) at least partially engages in the external toothing (4) and the conical section (3) of the first shaft (1) at least partially comes into contact with the conical section (5) of the second shaft (2). The invention also relates to a housing (20) for accommodating an electrical machine and a transmission, comprising such a bearing arrangement for two shafts (1, 2).

Description

The invention relates to a bearing arrangement comprising two shafts which are non-rotatably connected to one another via splines. Furthermore, the invention relates to a housing for accommodating an electrical machine, a transmission and the bearing arrangement with the two shafts.

If two shafts are connected to one another in a rotationally fixed manner, these shafts are permanently coupled within the meaning of the invention, so that they cannot rotate independently of one another. An at least partially torsionally flexible connection between two shafts is also understood to be fixed or non-rotatable.

Different bearing arrangements of shafts are well known. For example, a toothed end of a first shaft is inserted axially into the toothed end of a second shaft designed as a hollow shaft, as a result of which the two shafts are connected to one another in a torque-proof manner. Splines are known to have radial play. As the speed increases, the radial play can have a negative effect on the bearing arrangement of the two shafts and damage not only the splines themselves, but also the components that are effectively connected to the shafts to drive the shaft.

The object of the present invention is to provide an alternative bearing arrangement for two shafts and a housing with two shafts accommodated therein and mounted on one another. In particular, a radial play between the two shafts is to be eliminated.

The object is achieved by a bearing arrangement having the features of patent claim 1 and by a transmission having the features of patent claim 12. Advantageous embodiments are the subject matter of the dependent claims, the following description and the figures.

A bearing arrangement according to the invention comprises a first shaft, a second shaft and means for applying an axial force to at least one of the two shafts, the first shaft having a conical section and external teeth on an outer peripheral surface, the second shaft having a conical section and an inner peripheral surface has an internal toothing, the two shafts being arranged coaxially to one another and axially overlapping in such a way that the internal toothing at least partially engages in the external toothing and the conical section of the first shaft at least partially comes into contact with the conical section of the second shaft.

In other words, the means for applying an axial force to at least one of the two shafts and the conical sections on the two shafts result in a particularly advantageous self-centering of the two shafts arranged coaxially with one another, with radial play between the two shafts being reliably eliminated as a result. The axial force introduced into at least one of the two shafts presses the two shafts axially against one another in such a way that the two shafts with the conical sections come into contact with each other, preferably over a surface area and circumferentially, with the two conical sections forming a conical centering seat.

A conical section on a shaft means that the shaft is not cylindrical with a constant diameter over an axial length, but with a diameter that increases or decreases over the axial length, so that a cone shape is created.

An axial force is to be understood as a force that acts at least partially in the axial direction, ie in the longitudinal direction of the shaft. For example, the means for applying an axial force to at least one of the two shafts can introduce a force into at least one of the two shafts, which force can be divided into a number of force vectors, with at least one of the force vectors being directed axially and not equal to zero.

The engagement of the internal gearing with the external gearing connects the two shafts to one another in a torque-proof manner. In particular, the shafts are plugged into one another axially for this purpose.

According to a preferred embodiment, the first shaft is designed as a rotor shaft of an electrical machine. Furthermore, the second shaft is preferably designed as a pinion shaft of a transmission. In the context of the invention, a shaft is to be understood as meaning a rotatable component via which associated components of the electrical machine or the transmission are connected to one another in a torque-proof manner. The respective shaft can connect the components to one another axially or radially or both axially and radially. The respective shaft can also be present as an intermediate piece, via which a respective component is connected radially, for example. The term shaft does not exclude that the components to be connected can be made in one piece. In particular, the rotor shaft and the pinion shaft non-rotatably connected thereto are set up to rotate at speeds of more than 10,000 revolutions.

According to a preferred embodiment, a first bearing element is arranged radially outside of the internal toothing on an outer circumferential surface of the second shaft and is set up to be supported at least radially on a first non-rotating component. In particular, the first bearing element is designed to rotatably support both the first shaft and the second shaft. For example, the first bearing element is designed as a ball bearing and is set up to introduce at least radial forces, optionally also axial forces, into the first non-rotatable component. The first non-rotatable component can preferably be a permanently stationary component, preferably a housing, a part of such a housing or a component connected thereto in a non-rotatable manner.

According to a preferred embodiment, a second bearing element is arranged radially on an end section of the first shaft that is opposite to the external toothing and is set up to be supported at least radially on a second non-rotatable component. Consequently, the external teeth are preferably formed on an end portion of the first shaft. For example, the second bearing element is designed as a ball bearing and is set up to introduce at least radial forces, optionally also axial forces, into the second non-rotatable component. The second non-rotatable component can preferably be a permanently stationary component, preferably a housing, a part of such a housing or a component connected thereto in a non-rotatable manner.

According to a preferred embodiment, a third bearing element is arranged radially on an end section of the second shaft that is opposite to the internal toothing and is set up to be supported at least radially on a third non-rotatable component. Consequently, the internal teeth are preferably formed on an end portion of the second shaft. For example, the third bearing element is designed as a roller bearing or ball bearing and is set up to introduce at least radial forces, optionally also axial forces, into the third non-rotatable component. The third non-rotatable component can preferably be a permanently stationary component, preferably a housing, a part of such a housing or a component connected thereto in a non-rotatable manner.

According to a first embodiment, the means for applying the axial force to at least one of the two shafts comprises at least one spring element. In particular, the means for applying the axial force to at least one of the two shafts comprises a plurality of spring elements. For example, the means for applying the axial force to at least one of the two shafts comprises an annular spring assembly which applies an axial force at least indirectly to one of the two shafts.

The at least one spring element is preferably arranged between a non-rotatable component and a bearing element and applies an axial force to at least one of the two shafts indirectly via the bearing element. For example, the at least one spring element is arranged axially between a non-rotatable component, in particular a housing part, and the second bearing element, so that the first shaft is axially spring-loaded indirectly via the first bearing element and pressed into the conical centering seat.

According to a second embodiment, the means for applying the axial force acts on at least one of the two shafts hydraulically or magnetically on at least one of the two shafts. For example, a magnetic element or a magnetic device can be arranged on a non-rotatable component, preferably on the housing, which either drives one of the two shafts directly or indirectly via a further magnetic component or a further magnetic device, which can be arranged on the shaft into the conical centering seat. Alternatively, hydraulic means interact with one of the two shafts in such a way that it is pressed into the conical centering seat by hydraulic pressure.

According to a preferred embodiment, the conical section on the first shaft has a pitch angle of at least 10° and at most 40°. A lead angle on the first shaft is to be understood as meaning the acute angle between an axis of rotation of the shaft and a tangent on the conical section of the first shaft. In particular, it has been found that a helix angle of at least 10° to at most 40° represents a particularly efficient range for self-centering and eliminating the radial forces between the two shafts.

The conical section on the second shaft is preferably designed to correspond at least partially to the conical section on the first shaft. In other words, the conical section on the second shaft has an additional angle of approximately at least 140° to a maximum of 170°, with a pitch angle of the conical section on the second shaft essentially corresponding to the pitch angle on the first shaft, but being designed as an alternating angle.

According to a further aspect of the invention, a housing for accommodating an electric machine and a transmission is provided. The housing according to the invention has the bearing arrangement according to the invention with the first shaft, the second shaft and means for applying the axial force to at least one of the two shafts. In particular, the housing is designed to accommodate an electric drive unit for a motor vehicle.

According to a preferred embodiment, the housing comprises a first housing interior, which is designed to accommodate the electrical machine, and a second housing interior, which is designed to accommodate the transmission, the two housing interiors being axially separated by the first non-rotatable component, which in particular forms a housing wall are separated from each other. Accordingly, the electrical machine is arranged together with the first shaft designed as a rotor shaft in the first housing interior, with the transmission being arranged together with the second shaft designed as a pinion shaft in the second housing interior. In particular, the first shaft can protrude at least partially into the second housing interior, wherein the second shaft can protrude at least partially into the first housing interior, because the two shafts at least partially overlap axially.

The housing preferably has a plurality of non-rotatable components which are designed to accommodate bearing elements on the housing. In other words, the non-rotatable components are part of the housing and are designed to absorb at least radial forces, optionally also axial forces, from the bearing elements arranged thereon.

• 1 eine stark abstrahierte schematische Schnittansicht eines erfindungsgemäßen Gehäuses mit einer erfindungsgemäßen Lagerungsanordnung von zwei Wellen gemäß einer ersten Ausführungsform; und
• 2 eine stark abstrahierte schematische Schnittansicht eines erfindungsgemäßen Gehäuses mit einer erfindungsgemäßen Lagerungsanordnung von zwei Wellen gemäß einer zweiten Ausführungsform.

Advantageous embodiments of the invention, which are explained below, are shown in the drawings, with identical or similar components being provided with the same reference symbols. It shows:

• 1 a highly abstracted schematic sectional view of a housing according to the invention with a bearing arrangement according to the invention of two shafts according to a first embodiment; and
• 2 a highly abstracted schematic sectional view of a housing according to the invention with a storage arrangement according to the invention of two shafts according to a second embodiment.

1 shows a schematic sectional view of the housing 20 according to the invention according to a first embodiment. The housing 20 preferably has a multi-part design and is set up to accommodate an electrical machine and a transmission, with the electrical machine (not shown) being arranged in a first housing interior 21 , with the transmission (not shown) being arranged in a second housing interior 22 . The two housing interiors 21, 22 are axially separated from one another by a first non-rotatable component 8.1, which is designed as a housing wall.

Furthermore, in the housing 20 there is a bearing arrangement comprising a first shaft 1, a second shaft 2 and means which are set up here for applying an axial force to the first shaft 1. The first shaft 1 is designed as a rotor shaft of the electrical machine and has a conical section 3 on an outer peripheral surface and external teeth 4 on an end section. The second shaft 2 is designed as a pinion shaft of the transmission and has a conical section 5 and internal teeth 6 on an end section of an inner peripheral surface. In the present case, the second shaft 2 is designed as a hollow shaft and is provided with a toothed section 13 on an outer peripheral surface in order to connect further transmission components, which are not shown in detail. The rotor of the electrical machine is connected to the first shaft 1 in a torque-proof manner.

The two shafts 1, 2 are arranged coaxially to one another and are designed to rotate about a common axis of rotation 12. Furthermore, the two shafts 1, 2 are arranged so that they overlap axially in such a way that the internal toothing 6 engages at least partially in the external toothing 4 in order to form a non-rotatable plug-in connection, and the conical section 3 of the first shaft 1 at least partially adjoins the conical section 5 of the second shaft 2 comes to rest in order to center the shafts 1, 2 relative to one another and to eliminate radial play between the two shafts 1, 2.

A first bearing element 7.1 is arranged radially outside of the internal teeth 6 on an outer peripheral surface of the second shaft 2. The first bearing element 7.1 is supported on the first non-rotatable component 8.1, ie on the housing wall which axially separates the two housing interiors 21, 22 from one another. Furthermore, the first bearing element 7.1 is fixed axially on the first non-rotatable component 8.1 by means of a first locking ring 11.1 and is fixed axially on the second shaft 2 by means of a second locking ring 11.2.

A second bearing element 7.2 is arranged radially on an end section 9.1 of the first shaft 1 that is opposite to the external toothing 4. The second bearing element 7.2 is based on the second non-rotatable component 8.2, which is designed as a lateral housing wall or housing cover.

A third bearing element 7.3 is arranged radially on an end section 9.2 of the second shaft 2 which is opposite to the internal toothing 6 . The third bearing element 7.3 is supported on the third non-rotatable component 8.3, which is designed as a lateral housing wall or housing cover, and is axially fixed on the second shaft 2 by means of a third retaining ring 11.3. All of the non-rotatable components 8.1, 8.2, 8.3 are in the present case designed as housing components and are therefore connected to the housing 20 in a non-rotatable manner in one or more parts.

In the present case, the means for applying the axial force to the first shaft 1 is designed as a magnetic device, comprising a first component 14.1, which is arranged on the housing 20, and a second component 14.2, which is arranged on the front side of the first shaft 1. The two components 14.1, 14.2 of the magnetic device interact in such a way that the first shaft 1 is subjected to an axial force, whereby the conical section 3 on the first shaft 1 is pressed against the conical section 5 on the first shaft 2. In the present case, the conical section 3 on the first shaft 1 has a pitch angle of approximately 30°, with the conical section 5 on the second shaft 2 being designed to correspond to the conical section 3 on the first shaft 1, so that the two shafts 1, 2 in the area of the conical sections 3, 5 come to rest flat and circumferentially on one another.

2 shows a schematic sectional view of the housing 20 according to the invention according to a second embodiment. The second exemplary embodiment of the housing 20 differs from the first exemplary embodiment of the housing 20 in that the means for applying the axial force to the first shaft 1 comprises a plurality of spring elements 10. In the present case, the spring elements 10 are combined in an annular spring assembly which is arranged axially between the housing 20 and the second bearing element 7.2. The spring elements 10 apply an axial force to the first shaft 1 indirectly via the second bearing element 7.2, as a result of which the conical section 3 on the first shaft 1 is pressed against the conical section 5 on the first shaft 2. Furthermore, the first and the second bearing element 7.1, 7.2 are designed as ball bearings, with the third bearing element 7.3 being designed as a cylindrical roller bearing. Otherwise, the second embodiment of the housing 20 corresponds to the first embodiment of the housing 20 to which reference is made here.

Reference List

1

first wave

2

second wave

3

conical section on the first wave

4

External teeth on the first shaft

5

conical section on the second shaft

6

Internal gearing on the second shaft

7.1

first bearing element

7.2

second bearing element

7.3

third bearing element

8.1

first non-rotatable component

8.2

second non-rotatable component

8.3

third non-rotatable component

9.1

End section of the first wave

9.2

End section of the second shaft

10

spring element

11.1

first locking ring

11.2

second locking ring

11.3

third locking ring

12

axis of rotation

13

Splined section on the second shaft

14.1

first component

14.2

second component

20

Housing

21

first housing interior

22

second housing interior

Claims (14)

Bearing arrangement comprising a first shaft (1), a second shaft (2) and means for applying an axial force to at least one of the two shafts (1, 2), • the first shaft (1) having a conical section (3) on an outer peripheral surface and external teeth (4), • the second shaft (2) having a conical section (5) and internal teeth (6) on an inner peripheral surface, • the two shafts (1, 2) being arranged coaxially with one another and thus axially overlapping are that the internal toothing (6) engages at least partially in the external toothing (4) and the conical section (3) of the first shaft (1) at least partially As to the conical portion (5) of the second shaft (2) comes to rest. storage arrangement claim 1 , wherein the first shaft (1) is designed as a rotor shaft of an electrical machine. Bearing arrangement according to one of the preceding claims, wherein the second shaft (2) is designed as a pinion shaft of a transmission. Bearing arrangement according to one of the preceding claims, wherein a first bearing element (7.1) is arranged radially outside the internal toothing (6) on an outer peripheral surface of the second shaft (2) and is set up to be supported at least radially on a first non-rotatable component (8.1). Bearing arrangement according to one of the preceding claims, wherein a second bearing element (7.2) is arranged radially on an end section (9.1) of the first shaft (1) opposite to the external toothing (4) and is set up to be located at least radially on a second non-rotatable component (8.2) to support. Bearing arrangement according to one of the preceding claims, wherein a third bearing element (7.3) is arranged radially on an end section (9.2) of the second shaft (2) opposite the internal toothing (6) and is set up to be located at least radially on a third non-rotatable component (8.3) to support. Bearing arrangement according to one of the preceding claims, wherein the means for applying the axial force to at least one of the two shafts (1, 2) comprises at least one spring element (10). storage arrangement claim 7 wherein the at least one spring element (10) is arranged between a non-rotatable component and a bearing element and indirectly applies an axial force to at least one of the two shafts (1, 2) via the bearing element. Storage arrangement according to one of Claims 1 until 6 , wherein the means for applying the axial force to at least one of the two shafts (1, 2) acts hydraulically or magnetically on at least one of the two shafts (1, 2). Bearing arrangement according to one of the preceding claims, wherein the conical section (3) on the first shaft (1) has a pitch angle of at least 10° to at most 40°. Bearing arrangement according to one of the preceding claims, wherein the conical section (5) on the second shaft (2) is formed at least partially corresponding to the conical section (3) on the first shaft (1). Housing (20) for accommodating an electrical machine and a transmission, comprising a bearing arrangement according to one of the preceding claims. Housing (20) after claim 12 , comprising a first housing interior (21), which is designed to accommodate the electrical machine, and a second housing interior (22), which is designed to accommodate the transmission, the two housing interiors (21, 22) being separated by the first non-rotatable component (8.1 ) are axially separated from each other. Housing (20) after claim 12 or 13 , comprising a plurality of non-rotatable components (8.1, 8.2, 8.3), which are designed to accommodate bearing elements (7.1, 7.2, 7.3) on the housing (20).

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