DE102022121259A1 - Axial bearing arrangement for axially supporting a shaft and exhaust flap device - Google Patents

Abstract

The invention relates to an axial bearing arrangement (10) for axially supporting a shaft (12), comprising: the shaft (12), a bearing receiving structure (14), a bearing receiving space (16) which is radially delimited by the bearing receiving structure (14) and in which the shaft (12) is arranged, a first bearing element (18), which radially surrounds the shaft (12), is arranged in the bearing receiving space (16) and is attached to the bearing receiving structure (14), a second bearing element (20), which radially surrounds the shaft (12) and is attached to the shaft (12), a sliding disk (22) which freely rotatably surrounds the shaft (12) radially and in this way between the first bearing element (18) and the second bearing element (20) is arranged so that the sliding disk (22) rests axially on a first axial side on the first bearing element (18) and axially rests on a second axial side on the second bearing element (20), the sliding disk (22) in a radially inner edge region and/or in a radially outer edge region has a protruding section (36,38) which does not touch the first bearing element (18) and/or the second bearing element (20). The invention further relates to an exhaust flap device (100) with an axial bearing arrangement (10) according to the invention.

Description

The present invention relates to an axial bearing arrangement for axially supporting a shaft, comprising: the shaft, a bearing receiving structure, a bearing receiving space which is radially delimited by the bearing receiving structure and in which the shaft is arranged, a first bearing element which radially surrounds the shaft, in which Bearing receiving space is arranged and is attached to the bearing receiving structure, a second bearing element which radially surrounds the shaft and is attached to the shaft, a sliding disk which freely rotatably surrounds the shaft radially and is arranged between the first bearing element and the second bearing element, wherein the sliding disk abuts axially on the first bearing element in a first contact region and abuts axially on the second bearing element in a second contact region. The present invention further relates to an exhaust flap device with such an axial bearing arrangement.

Unless otherwise defined, the information “axial”, “radial” and “transverse” in the following refers to the shaft. Specifically, hereinafter, unless otherwise stated, an axial direction is parallel to a rotation axis of the shaft, a radial direction is perpendicular to the rotation axis of the shaft, and a transverse plane is transverse to the rotation axis of the shaft.

Generic axial bearing arrangements are known from the prior art and are used, among other things, for axially supporting the shaft in exhaust flap devices. Since the sliding disk in generic axial bearing arrangements typically consists of a significantly harder material than the two bearing elements, the sliding disk will "dig into" the two bearing elements over time due to abrasion during operation of the exhaust flap devices when the shaft is rotated, thereby affecting the properties of the axial bearing arrangement and thus affecting the exhaust flap device.

Against this background, the task is to create a long-lasting axial bearing arrangement for axially supporting a shaft or a long-lasting exhaust flap device.

This object is achieved by an axial bearing arrangement for axially supporting a shaft, with the features of claim 1, and by an exhaust flap device with the features of claim 12.

The axial bearing arrangement according to the invention for axially supporting a shaft comprises the shaft, a bearing receiving structure, and a bearing receiving space which is radially delimited by the bearing receiving structure and in which the shaft is arranged. The bearing receiving structure is generally formed by a housing part or a part fixedly mounted in or on a housing. The storage space is typically cylindrical. Typically, the shaft extends through the entire bearing receiving space and is arranged radially centered in the bearing receiving space.

The axial bearing arrangement according to the invention for axially supporting a shaft comprises two typically annular bearing elements, each of which radially surrounds the shaft. The first bearing element is arranged in the bearing receiving space and attached to the bearing receiving structure, and the second bearing element is attached to the shaft. The first bearing element is preferably pressed into the bearing receiving structure, and the second bearing element is preferably pressed onto the shaft. In principle, however, the two bearing elements can be attached to the bearing receiving structure or to the shaft in any way. For example, the bearing elements can also be glued, welded or screwed.

In the case of exhaust flap devices, temperatures of -50°C up to 650°C can also occur in the area of the axial bearing arrangement, so that the thermal properties, in particular the thermal expansion coefficients, are highly relevant when selecting the materials used. Furthermore, the materials used in axial bearing arrangements of exhaust flap devices must be insensitive to corrosion and allow as little adhesion as possible, for example from soot or water-containing oil mist, in order to prevent jamming. The bearing receiving structure and the two bearing elements therefore advantageously consist of a metal, with the bearing elements preferably consisting of a sintered metal powder and containing solid lubricants.

The axial bearing arrangement according to the invention for axially supporting a shaft comprises a sliding disk which surrounds the shaft radially in a freely rotatable manner. The sliding disk is mounted in a floating manner, i.e. it is not attached to the shaft, to the bearing receiving structure or to one of the bearing elements. The sliding disk is arranged between the first bearing element and the second bearing element in such a way that the sliding disk axially abuts the first bearing element on a first axial side and axially abuts the second bearing element on a second axial side. The sliding disk advantageously consists of a material that is harder than the materials from which the bearing elements are made.

According to the invention, the two bearing elements and the sliding disk are designed such that the sliding disk has a protruding section in a radially inner edge region and/or in a radially outer edge region, which does not touch the first bearing element and/or the second bearing element. The provision of the protruding section according to the invention prevents the sliding disk from touching the first bearing element and/or the second bearing element in the area of the radially outer outer edge or in the area of the radial inner inner edge, which reliably prevents the outer edge or the inner edge of the sliding disk from “digging in”. the corresponding bearing element is prevented. Preferably, the sliding disk has a protruding section both in the radially inner edge region and in the radially outer edge region, with both protruding sections touching neither the first bearing element nor the second bearing element, so that neither the inner edge nor the outer edge of the sliding disc dig into one of the two bearing elements can. This creates a long lasting thrust bearing assembly.

In order to reliably prevent the outer edge or the inner edge of the sliding disk from digging into the corresponding bearing element even if the sliding disk is slightly tilted relative to the first bearing element or relative to the second bearing element, each protruding section preferably has a radial expansion of at least 0.5 mm , which means that the outer edge or the inner edge of the sliding disk is arranged at least 0.5 mm away from a contact area between the sliding disk and the corresponding bearing element.

The protruding section of the sliding disk can be realized in a simple manner in that the first bearing element and/or the second bearing element have at least one annular recess on the axial side facing the sliding disk, the recess being axially adjacent to the inner edge region or the outer edge region of the sliding disk is arranged. Furthermore, the recess also forms a reservoir for abrasion that occurs during operation of the axial bearing arrangement and for contaminants introduced into the axial bearing arrangement, which prevents the abrasion or the contaminants from being deposited in a contact area between the sliding disk and the corresponding bearing element. This creates a particularly long-lasting thrust bearing arrangement. Preferably, the first bearing element has two annular recesses, with a recess being arranged axially adjacent to the inner edge region and a recess being arranged axially adjacent to the outer edge region of the sliding disk, and the second bearing element has an annular recess which is axially adjacent to the inner edge region the sliding disk is arranged.

A protruding section in the outer edge region of the sliding disk and in relation to the second bearing element can be realized in a simple manner in that the sliding disk has a radial outer diameter that is larger than a radial outer diameter of the second bearing element.

Preferably, the sliding disk has a convex surface on an axial side and the first bearing element or second bearing element opposite the convex surface has a concave surface formed corresponding to the convex surface of the sliding disk on the axial side facing the sliding disk, the convex surface of the sliding disk rests on the concave surface of the first bearing element or the second bearing element. This ensures flat contact between the sliding disk and the first bearing element or the second bearing element, even if the sliding disk is slightly tilted relative to the first bearing element or relative to the second bearing element. Furthermore, the shape of the contacting surfaces also prevents unwanted radial displacement of the sliding disk. This creates a particularly reliable axial bearing arrangement.

Preferably, the second bearing element and the sliding disk are arranged within the bearing receiving space, so that they are reliably protected from environmental influences.

Preferably, a radial outer diameter of the second bearing element is at least 0.5 mm, particularly preferably at least 1.0 mm, smaller than a radial diameter of the bearing receiving space, so that there is at least 0.5 mm wider between the radial outside of the second bearing element and an inner wall of the bearing receiving structure Annular gap is present. Abrasion that occurs during operation of the axial bearing arrangement can be removed via the annular gap, thereby preventing the abrasion from being deposited in contact areas between the sliding disk and the two bearing elements. This creates a particularly long-lasting thrust bearing arrangement.

Since the two bearing elements typically consist of a metal, particularly good tribological properties can be achieved between the sliding disc and the bearing elements can be realized in that the sliding disc is made of ceramic.

In many areas of application of axial bearing arrangements, especially in an exhaust flap device, it must be prevented that fluid can escape along the shaft. Preferably, an annular gap existing between the bearing receiving structure and the shaft is closed in a fluid-tight manner by the first bearing element, the second bearing element and the sliding disk, so that axial flow through the bearing receiving space is prevented. The first bearing element is fastened to the bearing receiving structure in such a way that there is no gap between an outside of the first bearing element and the bearing receiving structure or this is closed in a fluid-tight manner. For this purpose, the first bearing element is preferably pressed into the bearing receiving structure. The second bearing element is in turn attached to the shaft in such a way that there is no gap between an inside of the second bearing element and the shaft or this is closed in a fluid-tight manner. For this purpose, the second bearing element is preferably pressed onto the shaft. Furthermore, the two bearing elements and the sliding disk are designed such that the sliding disk rests along its entire circumference on both the first bearing element and the second bearing element. For this purpose, as already described above, the sliding disk and at least one of the bearing elements preferably have surfaces which are convex/concave to correspond to one another. On the one hand, this creates a relatively large contact surface and thus a relatively good sealing effect between the sliding disk and the corresponding bearing element, and on the other hand, even if the sliding disk is slightly tilted relative to the corresponding bearing element, there is flat contact between the sliding disk and the corresponding bearing element along the entire circumference ensured. This creates an axial bearing arrangement that also functions as a shaft seal, so that no additional sealants need to be provided for this purpose.

The exhaust flap device according to the invention comprises a flow housing, a flow channel which is formed in the flow housing, and a shaft which is rotatably mounted in the flow housing and at least projects into the flow channel. The shaft preferably extends through the entire flow channel and is rotatably mounted on both axial sides of the flow channel via a radial bearing.

The exhaust flap device according to the invention comprises a flap body which is arranged in the flow channel and attached to the shaft. The flap body is designed and arranged in a known manner, such that a flow-through cross section of the flow channel can be regulated by rotating the flap body using the shaft.

The exhaust flap device according to the invention comprises a previously described axial bearing arrangement according to the invention for axially supporting the shaft in the flow housing, the bearing receiving structure being formed on the flow housing. The axial bearing arrangement according to the invention creates a long-lasting exhaust flap device. Preferably, the axial bearing arrangement is designed as described above in such a way that axial flow through the bearing receiving space is prevented, so that no additional sealing means need to be provided in order to prevent exhaust gas from escaping from the flow channel along the shaft.

• 1 eine erfindungsgemäße Abgasklappenvorrichtung mit einer erfindungsgemäßen Axiallageranordnung in geschnittener Darstellung, und
• 2 eine vergrößerte Darstellung eines die Axiallageranordnung umfassenden Ausschnitts der Abgasklappenvorrichtung aus 1.

An exemplary embodiment of the present invention is described below with reference to the attached figures. This shows:

• 1 an exhaust flap device according to the invention with an axial bearing arrangement according to the invention in a sectional view, and
• 2 an enlarged view of a section of the exhaust flap device comprising the axial bearing arrangement 1 .

1 shows an exhaust flap device 100 with a flow housing 102, in which two flow channels 104a, 104b are formed.

The exhaust flap device 100 includes a shaft 12 and two flap bodies 110a, 110b, each of which is attached to the shaft 12, the first flap body 110a being arranged in the first flow channel 104a and the second flap body 110b being arranged in the second flow channel 104b.

The shaft 12 is rotatably mounted radially in the flow housing 102 via three radial bearings 106a-106c and axially via an axial bearing arrangement 10, and a lever element 112 is fastened to an end of the shaft 12 protruding from the flow housing 102, via which the shaft 12 is not connected by one Actuator shown can be rotated.

The radial bearings 106a-106c are each arranged in a radial bearing receiving structure 108a-108c formed in the flow housing 102. The first radial bearing receiving structure 108a with the first radial bearing 106a is arranged on the axial side of the first flow channel 104a facing away from the second flow channel 104b. The second radial bearing receiving structure 108b with the second radial bearing 106b is arranged between the first flow channel 104a and the second flow channel 104b. The third radial bearing receiving structure 108c with the third radial bearing 106c is arranged on the axial side of the second flow channel 104b facing away from the first flow channel 104a.

In addition to the shaft 12, the axial bearing arrangement 10 includes a bearing receiving structure 14, which is formed on an outside of the flow housing 102 on the axial side facing the lever element 112. The bearing receiving structure 14 delimits a circular cylindrical bearing receiving space 16 designed as a blind hole, through which the shaft 12 extends, radially outwards.

The axial bearing arrangement 10 further comprises an annular first bearing element 18, an annular second bearing element 20 and an annular sliding disk 22, each of which radially surrounds the shaft 12 and is arranged in the bearing receiving space 16.

The first bearing element 18 consists of a metal and is pressed into the bearing receiving structure 14. The first bearing element 18 has on the axial side facing the sliding disk 22 two annular recesses 24a, 24b running around the shaft 12, the recess 24a being arranged in the radially inner edge region of the first bearing element 18 and the recess 24b in the radially outer edge region of the first Bearing element 18 is arranged. The first bearing element 18 also has a concave surface 26 on the axial side facing the sliding disk 22 in a contact area with the sliding disk 22 formed between the two annular recesses 24a, 24b.

The second bearing element 20 consists of a metal and is pressed onto the shaft 12. The second bearing element 20 has a radial outer diameter D1 which is at least 1.0 mm smaller than a radial diameter D2 of the bearing receiving space 16. The second bearing element 20 has a flat surface 28 on the axial side facing the sliding disk 22 and in the radially inner edge region an annular recess 30.

The sliding disk 22 consists of a ceramic and has a radial outer diameter D3 which is larger than the radial outer diameter D1 of the second bearing element 20. The sliding disk 22 is arranged between the first bearing element 18 and the second bearing element 20, with the sliding disk 22 both with respect to the bearing receiving structure 14 as well as with respect to the shaft 12 is freely rotatable, i.e. is not attached to one of the two bearing elements 18, 20 nor to the bearing receiving structure 14 nor to the shaft 12. A spring element 114 is arranged between the lever element 112 and the flow housing 102, through which the lever element 112 is pushed away from the flow housing 102 and thus the shaft 12 is subjected to an axial force in such a way that the sliding disk 22 is moved by the second one attached to the shaft 12 Bearing element 20 is pressed axially onto the first bearing element 18 attached to the bearing receiving structure 14.

On the axial side facing the first bearing element 18, the sliding disk 22 has a convex surface 32, which is designed to correspond to the concave surface 26 of the first bearing element 18 and rests axially on the concave surface 26. On the axial side facing the second bearing element 20, the sliding disk 22 has a flat surface 34, which rests axially on the flat surface 28 of the second bearing element 20. Consequently, an annular gap 35 existing between the bearing receiving structure 14 and the shaft 12 is closed in a fluid-tight manner by the two bearing elements 18, 20 and the sliding disk 22 in such a way that axial flow through the bearing receiving space 16 is prevented.

The sliding disk 22 has an inner projection section 36 in a radially inner edge region and an outer projection section 38 in a radially outer edge region, with both projection sections 36, 38 touching neither the first bearing element 18 nor the second bearing element 20. The inner projection section 36 is formed by the recess 24b of the first bearing element 18 and the recess 30 of the second bearing element 20, and the outer projection section 38 is formed by the recess 24a of the first bearing element 18 and the difference between the outer diameter D1 of the second bearing element 20 and that Diameter D2 of the bearing receiving space 16 is formed.

A radial distance between an inner circumferential surface 40 of the sliding disk 22 and a circumferential surface 42 of the recess 24b of the first bearing element 18 and a radial distance between the inner circumferential surface 40 of the sliding disk 22 and a circumferential surface 44 of the recess 30 are each at least 0.5 mm. A radial distance between an outer peripheral surface 46 of the sliding disk 22 and a peripheral surface 48 of the recess 24a of the first bearing element 18 and a radial distance between the outer peripheral surface 46 of the sliding disk 22 and an outer peripheral surface 50 of the second bearing element 20 are each at least 0.5 mm. Both protruding sections 36,38 each have a radial extent of at least 0.5 mm.

Reference symbol list

10

Thrust bearing arrangement

12

Wave

14

Storage structure

16

storage room

18.20

Bearing elements

22

Sliding disc

24a,24b,30

annular recesses

26

concave surface

28.34

flat surfaces

32

convex surface

35

Annular gap

36.38

Overhang sections

40-50

Circumferential surfaces

100

Exhaust flap device

102

Flow housing

104a,104b

Flow channels

106a-106c

Radial bearing

108a-108c

Radial bearing receiving structures

110a,110b

Flap body

112

Lever element

114

Spring element

D1,D3

outer diameter

D2

diameter

Claims (10)

Axial bearing arrangement (10) for axially supporting a shaft (12), comprising: - the shaft (12), - a bearing receiving structure (14), - a bearing receiving space (16), which is radially delimited by the bearing receiving structure (14) and in which the Shaft (12) is arranged, - a first bearing element (18), which radially surrounds the shaft (12), is arranged in the bearing receiving space (16) and is attached to the bearing receiving structure (14), - a second bearing element (20) which surrounds the shaft (12) radially and is attached to the shaft (12), - a sliding disk (22) which surrounds the shaft (12) in a freely rotatable radial manner and is thus between the first bearing element (18) and the second bearing element ( 20) is arranged so that the sliding disk (22) rests axially on a first axial side on the first bearing element (18) and axially rests on a second axial side on the second bearing element (20), characterized in that the sliding disk (22) in a radially inner edge region and/or in a radially outer edge region has a protruding section (36,38) which does not touch the first bearing element (18) and/or the second bearing element (20). Thrust bearing arrangement (10) according to one of the preceding claims, wherein each protruding section (36,38) has a radial extent of at least 0.5 mm. Axial bearing arrangement (10) according to one of the preceding claims, wherein the first bearing element (18) and/or the second bearing element (20) have at least one annular recess (24a, 24b, 30) on the axial side facing the sliding disk (22). Axial bearing arrangement (10) according to one of the preceding claims, wherein a radial outside diameter (D3) of the sliding disk (22) is larger than a radial outside diameter (D1) of the second bearing element (20). Axial bearing arrangement (10) according to one of the preceding claims, wherein the sliding disk (22) has a convex surface (32) on an axial side and the first bearing element (18) or second bearing element (20) opposite the convex surface (32) on the The axial side facing the sliding disk (22) has a concave surface (26). Axial bearing arrangement (10) according to one of the preceding claims, wherein the second bearing element (20) and the sliding disk (22) are arranged within the bearing receiving space (16). Axial bearing arrangement (10). Claim 6 , wherein a radial outer diameter (D1) of the second bearing element (20) is at least 0.5 mm smaller than a radial diameter (D2) of the bearing receiving space (16). Axial bearing arrangement (10) according to one of the preceding claims, wherein the sliding disk (22) consists of a ceramic. Axial bearing arrangement (10) according to one of the preceding claims, wherein an annular gap (35) present between the bearing receiving structure (14) and the shaft (12) through the first bearing element ment (18), the second bearing element (20) and the sliding disk (22) are sealed in a fluid-tight manner, so that axial flow through the bearing receiving space (16) is prevented. Exhaust flap device (100) comprising: - a flow housing (102), - a flow channel (104a, 104b) which is formed in the flow housing (102), - a shaft (12) which is rotatably mounted in the flow housing (102) and projects into the flow channel (104a, 104b), - a flap body (110a, 110b), which is arranged in the flow channel (104a, 104b) and attached to the shaft (12), and - an axial bearing arrangement (10) according to one of the preceding claims for axially supporting the shaft (12) in the flow housing (102), the bearing receiving structure (14) of the axial bearing arrangement (10) being formed on the flow housing (102).

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