DISK SPRING FOR A VARIABLE TURBINE GEOMETRY OF AN EXHAUST GAS TURBOCHARGER

Abstract

A disk spring may include an annular base body, a central longitudinal axis of which defines an axial direction of the base body. A profile of the base body in a profile plane containing the central longitudinal axis may have a wave-shaped contour with two minima including a radially inner minimum and a radially outer minimum and with an intermediate maximum disposed between the two minima. The wave-shaped contour may extend from a radially inner end point to a radially outer end point. The radially inner end point may be arranged offset in the axial direction with respect to the radially outer end point.

Claims

1. A disk spring, comprising: an annular base body, a central longitudinal axis of which defines an axial direction of the base body; wherein a profile of the base body in a profile plane containing the central longitudinal axis has a wave-shaped contour with two minima including a radially inner minimum and a radially outer minimum and with an intermediate maximum disposed between the two minima, the wave-shaped contour extending from a radially inner end point to a radially outer end point, the radially inner end point arranged offset in the axial direction with respect to the radially outer end point.

2. The disk spring according to claim 1, wherein the base body has a first turning point and a second turning point in the profile which are arranged in a common plane extending perpendicularly to the axial direction.

3. The disk spring according to claim 2, wherein the first turning point, the second turning point, and the common plane are arranged at a height of the radially outer end point in relation to the axial direction.

4. The disk spring according to claim 1, wherein: the profile has a radially inner profile section delimited radially inwards by the radially inner end point and a radially outer profile section delimited radially outwards by the radially outer end point and disposed spaced apart from the radially inner profile section; a contour of the radially outer profile section is a mirroring of a contour of the radially inner profile section relative to a mirror axis extending between the radially outer profile section and the radially inner profile section parallel to the central longitudinal axis of the base body; and the contour of the radially outer profile section is disposed offset to the contour of the radially inner profile section in the axial direction.

5. The disk spring according to claim 4, wherein the radially inner profile section and the radially outer profile section are arranged offset with respect to one another by a same amount along the axial direction as the radially inner end point and the radially outer end point.

6. The disk spring according to claim 4, wherein: the base body has a first turning point and a second turning point in the profile which are arranged in a common plane extending perpendicularly to the axial direction; and the radially inner profile section is delimited radially outwards by the second turning point.

7. The disk spring according to claim 4, wherein the radially inner minimum is arranged in the radially inner profile section and the radially outer minimum is arranged in the radially outer profile section.

8. The disk spring according to claim 4, wherein the profile has a transition profile section extending between the radially inner profile section and the radially outer profile section in which the intermediate maximum is arranged.

9. The disk spring according to claim 8, wherein the radially inner profile section and the radially outer profile section each extend continuously and bend-free into the transition profile section.

10. The disk spring according to claim 8, wherein the base body has a first turning point, a second turning point, and a third turning point in the profile, the second turning point disposed radially between the first turning point and the third turning point, the first turning point and the second turning point arranged in a common plane extending perpendicularly to the axial direction, and wherein at least one of: the radially inner profile section adjoins the transition profile section at the second turning point; and the radially outer profile section adjoins the transition profile section at the third turning point.

11. The disk spring according to claim 10, wherein the third turning point in relation to the axial direction is arranged offset with respect to the common plane in which the first turning point and second turning point are arranged.

12. The disk spring according to claim 1, wherein the profile is structured to be at least one of continuous and bend-free.

13. A variable turbine geometry for an exhaust gas turbocharger, comprising a bearing housing and a disk spring arranged on the bearing housing, the disk spring including an annular base body, a central longitudinal axis of which defines an axial direction of the base body; wherein a profile of the base body in a profile plane containing the central longitudinal axis has a wave-shaped contour with two minima including a radially inner minimum and a radially outer minimum and with an intermediate maximum disposed between the two minima, the wave-shaped contour extending from a radially inner end point to a radially outer end point, the radially inner end point arranged offset in the axial direction with respect to the radially outer end point.

14. An exhaust gas turbocharger for an internal combustion engine of a motor vehicle, comprising a compressor, a turbine, and a variable turbine geometry, the variable turbine geometry including a bearing housing and a disk spring arranged on the bearing housing, the disk spring including an annular base body, a central longitudinal axis of which defines an axial direction of the base body; wherein a profile of the base body in a profile plane containing the central longitudinal axis has a wave-shaped contour with two minima including a radially inner minimum and a radially outer minimum and with an intermediate maximum disposed between the two minima, the wave-shaped contour extending from a radially inner end point to a radially outer end point, the radially inner end point arranged offset in the axial direction with respect to the radially outer end point.

15. The disk spring according to claim 1, wherein the profile is structured to extend continuously without a step and to be bend-free.

16. The disk spring according to claim 1, wherein the base body has a first turning point, a second turning point, and a third turning point in the profile, the second turning point disposed radially between the first turning point and the third turning point, the first turning point and the second turning point arranged in a common plane extending perpendicularly to the axial direction.

17. The disk spring according to claim 16, wherein the profile has: a radially inner profile section extending between the inner radially end point and the second turning point, the radially inner minimum disposed in the radially inner profile section; a transition profile section extending between the second turning point and the third turning point, the intermediate maximum disposed in the transition profile; and a radially outer profile section extending between the third turning point and the radially outer end point, the radially outer minimum disposed in the radially outer profile section;

18. The disk spring according to claim 16, wherein the wave-shaped contour defines a constant radius of curvature between the first turning point and the second turning point.

19. The disk spring according to claim 18, wherein a distance between the radially inner minimum and the common plane relative to the axial direction is approximately of the radius of curvature.

20. The disk spring according to claim 18, wherein a radial distance between the radially inner end point and the radially inner minimum is equal to the radius of curvature plus two times an axial distance between the radially inner end pint and the radially outer end point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the figures, in each case schematically:

[0027] FIG. 1 shows an example of a disk spring according to the invention in a lateral sectional view,

[0028] FIG. 2 shows the disk spring of FIG. 1 in profile.

DETAILED DESCRIPTION

[0029] FIG. 1 shows an example of a disk spring 1 according to the invention in a lateral sectional view. The disk spring 1 comprises an annular base body 2 which can be formed by a sheet metal moulding. An axial direction A of the base body 2 is defined by a central longitudinal axis M of the base body 2. The base body 2 extends along a circumferential direction U which runs perpendicular to the central longitudinal axis M and therefore also to the axial direction A and borders a through-opening. A radial direction R extends perpendicular to the central longitudinal axis M and thus also extends perpendicularly to the axial direction A and perpendicularly to the circumferential direction U.

[0030] FIG. 2 shows a profile 3 of the base body 2 in a profile plane P which contains the central longitudinal axis M. Accordingly, the profile 3 has a wave-shaped contour 4 which extends from a radially inner end point 5a to a radially outer end point 5b. In this case, the radially inner end point 5a is arranged offset along the axial direction A with respect to the radially outer end point 5b. The profile 3 of the base body 2 as shown in FIG. 2 is preferably continuous, in particular without forming a step, and also bend-free.

[0031] According to FIG. 1, the base body 2 has a first and a second turning point 6a, 6b in the profile 3, which are both arranged in a common plane E which in turn extends perpendicular to the axial direction A. The common plane E intersects the profile plane P orthogonally. In relation to the axial direction A, the two turning points 6a, 6b and therefore also the common plane E are arranged at the height of the radially outer end point 5b.

[0032] According to FIG. 2, the profile 3 of the base body 2 has a radially inner profile section 8a which is delimited radially inwards by the inner end point 5a and a radially outer profile section 8b which is delimited radially outwards by the outer end point 5b. The radially inner profile section 8a goes over into the radially outer profile section 8b by means of a transition profile section 8c, i.e. the radially inner profile section 8a and the radially outer profile section 8b are arranged at a distance from one another along the radial direction R. The radially inner profile section 8a and the radially outer profile section 8b in this case go over continuously and bend-free into the transition profile section 8c. The contour 4 of the radially outer profile section 8b is a mirroring of the radially inner profile section 8a on a mirror axis S running between the two profile sections parallel to the central longitudinal axis M of the base body 2.

[0033] As clearly confirmed in FIG. 2, the contour 4 of the radially outer profile section 8b is offset in the axial direction A with respect to the contour 4 of the radially inner profile section 8a. In this case, the radially inner and the radially outer profile section 8a, 8b are arranged offset with respect to one another along the axial direction by the same amount h as the inner and the outer end point 5a, 5b. The radially inner profile section 8a adjoins the transition profile section 8c at the second turning point 6b. The radially outer profile section 8b adjoins the transition profile section 8c at a third turning point 6c which is different at the first and second turning point 6a, 6b. The third turning point 6c delimits the radially outer profile section 8b inwards. The radially inner profile section 8a is delimited radially outwards by the second turning point 6b.

[0034] As can be seen in FIG. 2, the third turning point 6c is arranged in relation to the axial direction A offset with respect to the common plane E in which the first and second turning points 6a, 6b are arranged.

[0035] As can also be seen in FIG. 2, the profile of the base body 2 has a radially inner and a radially outer minimum 9a, 9b as an intermediate maximum 10 arranged between these two minima 9a, 9b. The radially inner minimum 9a is arranged in the radially inner profile section 8a and the radially outer minimum 10b is arranged in the radially outer profile section 8b. The intermediate maximum 10 is arranged in the transition profile section 8c.

[0036] In the example of FIG. 2 the contour 4 has a predetermined radius of curvature r between the two turning points 6a, 6b. A distance y of the radially inner minimum 9a to the plane E measured along the axial direction A is a quarter of the radius of curvature r, i.e. y=0.25 r. A distance x between the radially inner end point 5a and the radially inner minimum 9a measured along the radial direction R obeys the relationship: x=r+2*h.