DISK SPRING FOR AN EXHAUST GAS TURBOCHARGER

Abstract

A disk spring for an exhaust gas turbocharger is provided. The disk spring includes an annular base body extending around a central longitudinal axis and along a circumferential direction of the disk spring and enclosing a disk opening. Preload elements are formed on an inner circumference of the base body for exerting a preload force on a mounting section of an exhaust gas turbocharger inserted into the disk opening.

Claims

1. A disk spring for an exhaust gas turbocharger, the disk spring comprising: an annular base body extending around a central longitudinal axis and along a circumferential direction of the disk spring and enclosing a disk opening, wherein preload elements are formed on an inner circumference of the base body for exerting a preload force on a mounting section of an exhaust gas turbocharger inserted into the disk opening.

2. The disk spring according to claim 1, wherein at least one preload element, typically all preload elements, is/are formed by an projection projecting radially inwards on the inner circumference of the base body and bent over away from the central longitudinal axis.

3. The disk spring according to claim 1, wherein the at least one preload element or the at least one projection is formed or bent over in such a way that the preload force generated by it acts in a radial direction of the disk spring which extends orthogonally away from the central longitudinal axis.

4. The disk spring according to claim 1, wherein in a cross-section perpendicular to the central longitudinal axis, typically also in a plan view of the base body along the central longitudinal axis, at least two, typically several, preload elements or projections are arranged at a distance from one another on the inner circumference along the circumferential direction.

5. The disk spring according to claim 1, wherein in the cross section perpendicular to the central longitudinal axis a recess is formed between two adjacent preload elements or projections with respect to the circumferential direction.

6. The disk spring according to claim 5, wherein at least one recess is formed as a slot-like opening extending along the radial direction of the disk spring.

7. The disk spring according to claim 2, wherein in the longitudinal section along the central longitudinal axis, a radially inner end portion of at least one projection extends parallel to the central longitudinal axis.

8. The disk spring according to claim 1, wherein the base body is formed as a shaped sheet metal part with a predetermined sheet thickness.

9. The disk spring according to claim 8, wherein an axially measured section length of the radially inner end portion extending parallel to the central longitudinal axis is at least two, typically at least three and at the most ten, most typically at the most five sheet thicknesses.

10. The disk spring according to claim 7, wherein in the longitudinal section along the central longitudinal axis, the radially inner end portionto form a contact surface for the exhaust gas turbochargermerges radially outwards into a contact portion which extends perpendicularly to the central longitudinal axis.

11. The disk spring according to claim 1, wherein the preload elements or the projections are integrally formed on the base body.

12. The disk spring according to claim 1, wherein the base body without the preload elements is designed rotationally symmetrical to the central longitudinal axis.

13. The disk spring according to claim 1, wherein in the longitudinal section along the central longitudinal axis, the base body and the preload elements or the projections together form an S-shaped geometry.

14. The disk spring according to claim 1, wherein exactly three preload elements or projections are provided, which are arranged equidistantly to one another along the circumferential direction.

15. An exhaust gas turbocharger, comprising: a turbine which has a turbine housing and a turbine wheel accommodated in the turbine housing, a disk spring according to claim 1, a bearing housing which has a mounting section which passes through the disk opening of the disk spring, such that the disk spring is fixed to the bearing housing for forming a heat shield which, during operation of the exhaust gas turbocharger, shields the bearing housing against heat generated by the turbine.

16. The exhaust gas turbocharger according to claim 15, wherein the preload elements formed on the base body exert a preload force on the mounting section of the bearing housing.

17. The exhaust gas turbocharger according to claim 15, wherein the preload force generated by the preload elements and exerted on the mounting portion of the bearing housing acts substantially in the radial direction of the disk spring

18. The exhaust gas turbocharger according to claim 15, wherein the preloading elements lie flat against the mounting section of the bearing housing.

19. The exhaust gas turbocharger according to claim 15, wherein the disk spring with a radially outer end portion of the base body bears axially against a guide vane carrier of the exhaust gas turbocharger, such that the disk spring pretensions the guide vane carrier axially to the turbine housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The disclosure will now be described with reference to the drawings wherein:

[0045] FIG. 1 shows a disk spring in a cross-section perpendicular to the central longitudinal axis of the disk spring according to an exemplary embodiment of the disclosure,

[0046] FIG. 2 shows the disk spring shown in FIG. 1 in a longitudinal section along the central longitudinal axis,

[0047] FIG. 3 shows a detailed representation of the disk spring of FIG. 2 in the area of a preload element,

[0048] FIG. 4 shows the disk spring shown in FIG. 2 with an additional heat shield according to a further exemplary embodiment of the disclosure,

[0049] FIG. 5 shows a schematic partial representation of an exhaust gas turbocharger with the disk spring shown in FIGS. 1 to 3 mounted on the bearing housing of the exhaust gas turbocharger according to an exemplary embodiment of the disclosure, and

[0050] FIG. 6 shows the exhaust gas turbocharger according to FIG. 5 with the disk spring according to FIG. 4.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0051] FIG. 1 shows an example of a disk spring 1 according to an exemplary embodiment of the disclosure in a cross-section perpendicular to a central longitudinal axis M of disk spring 1, FIG. 2 in a longitudinal cross-section along this central longitudinal axis M. FIG. 1 shows the disk spring 1 along the section line I-I of FIG. 2. For use as a heat shield, the disk spring 1 is usually made of heat-resistant steels, nickel or cobalt alloys, which even above a temperature of 800 C. still have well over fifty percent of their yield strength.

[0052] According to FIGS. 1 and 2, disk spring 1 comprises an annular base body 2, which extends along a circumferential direction U of disk spring 1 around the central longitudinal axis M, which in turn extends along an axial direction A. The circumferential direction U extends perpendicular to the axial direction A and revolves around the central longitudinal axis M. A radial direction R extends orthogonally away from the central longitudinal axis M and also extends perpendicular to both the axial direction A and the circumferential direction U.

[0053] As can be seen in FIG. 1, on an inner circumference 5 of the ring-shaped base body 2, which encloses and radially limits the disk opening 3, preload elements 10 are formed to exert a preload force on a mounting section (not shown in FIG. 1) of an exhaust gas turbocharger inserted into the disk opening 3. The preload elements 10 are formed by projections 9 projecting radially inwards on the inner circumference 5.

[0054] In the example of FIG. 1, three preload elements 10 or three projections 9 are shown, which are arranged at a distance from each other along the circumferential direction U. In variants of the example, a different number of preload elements 10 or projections 9 may be provided. The preload elements 10 or the projections 9 are integrally formed on the base body 2; the preload elements 10 or the projections 9 and the base body 2 are therefore formed in one piece and of the same material.

[0055] As FIG. 1 illustrates, the base body 2 is rotationally symmetrical to the central longitudinal axis M without the preload elements 10 or the projections 9.

[0056] In the cross-section perpendicular to the central longitudinal axis M shown in FIG. 1, a recess 6 is formed between each two adjacent preload elements 10 or projections 9 in the circumferential direction U. The recesses 6 can typically be designed as slot-like openings extending in the radial direction R of the disk spring 1 (not shown).

[0057] According to FIG. 2, in the longitudinal section along the central longitudinal axis M the projections 9 are bent away from the central longitudinal axis M. Thus, the preload elements 10 or projections 9 can each generate a preload force acting in the radial direction R. It is further to be seen from FIG. 2 that in the longitudinal section along the central longitudinal axis M, the base body 2 and the preload elements 10 or the projections 9 together form an S-shaped geometry.

[0058] According to FIGS. 2 and 3the latter being a detailed representation of FIG. 2 in the area of the inner circumference 5in the longitudinal section along the central longitudinal axis M, a radially inner end portion 8 of the respective projection 9 extends parallel to the central longitudinal axis M.

[0059] The base body 2 can be designed as a sheet metal part 11 with a predetermined sheet thickness B. A section length 1, measured along the axial direction A, of the radially inner end portion 8 extending parallel to the central longitudinal axis M is at least two sheet thicknesses B, preferably at least three sheet thicknesses B.

[0060] As FIG. 3 furthermore illustrates, in the longitudinal section shown, along the central longitudinal axis M, the radially inner end portion 8 for forming a contact surface for the turbocharger merges radially outwards into a contact portion. This contact portion 12 extends along the radial direction R and thus perpendicular to the central longitudinal axis M. The contact portion 12 merges radially outwards into a central portion 14, which may be arranged at an acute angle to the central longitudinal axis M in the longitudinal section of FIG. 2. The central portion 14 again merges radially outwards into a radially outer end portion 13.

[0061] Preload elements 10 or bent projections 9 and recesses 6 are arranged equidistantly to each other on the inner circumference 5 with respect to the circumferential direction U, i.e., two adjacent recesses 6 along the circumferential direction U and also two adjacent projections 9 along the circumferential direction U are arranged at a uniform, i.e. the same, distance from each other.

[0062] FIG. 4 shows a further exemplary embodiment of the example of FIG. 3. In the exemplary embodiment of FIG. 4 the disk spring 1 comprises an additional annular heat shield 4, which is arranged axially adjacent to the base body 2 of the disk spring 1 and rests axially on the contact portion 12 of the disk spring 1. In particular, the additional heat shield 4 may have a heat shield opening 7 into which the radially inner end portion 8 of the disk spring 1 is inserted. In this way, the heat shield 4 and the base body 2 are firmly fixed together. The additional heat shield 4 and the main body 2 are thus designed in two parts.

[0063] FIG. 5 illustrates the use of the disk spring 1 according to FIGS. 1 to 3 as explained above in an exhaust gas turbocharger 20 for an internal combustion engine. The exhaust gas turbocharger 20 comprises a turbine which has a turbine housing and a turbine wheel (not shown) accommodated in the turbine housing. The exhaust gas turbocharger 20 further comprises a disk spring 1 as explained above, which is in accordance with the disclosure. The exhaust gas turbocharger 20 also comprises a bearing housing 21, which has a mounting section 22 for fastening the disk spring 1. In the state of the disk spring 1 mounted in the turbocharger 20, as shown in FIG. 4, the mounting section 22typically of bolt-like designpasses through the disk opening 3.

[0064] The preload elements 10 formed on the base body 2 or the bent projections 9 rest flat against the mounting section 22 of the bearing housing 21 and exert a preload force acting in radial direction R on the mounting section 22 of the bearing housing 21. In this way the disk spring 1 is fixed to the mounting section 22 of the bearing housing 21.

[0065] As shown in FIG. 5, the disk spring 1 is located between the turbine housing and bearing housing 21. Thus, the disk spring 1 can act as a heat shield, shielding the bearing housing 21 and components of the exhaust gas turbocharger 20 located behind the bearing housing 21this includes in particular components that are part of the compressor (not shown) of the exhaust gas turbocharger 20against heat generated in the turbine during operation of the exhaust gas turbocharger 20.

[0066] In particular, the disk spring 1 as shown in FIG. 5 with the radially outer end portion 13 of the base body 2 is in axial contact with a guide vane carrier 24 of the exhaust gas turbocharger 20, so that the disk spring 1 pretensions the guide vane carrier 24 axially to the turbine housing. In this way, the guide vane carrier 24 is firmly fixed to the turbine housing.

[0067] In the course of the assembly of the exhaust gas turbocharger 20, the disk spring 1 is first placed on the typically nose-shaped mounting section 22 provided on the bearing housing in a force-locking manner, so that the mounting section 22 then passes through the disk spring 1.

[0068] Then the shaft 23 of the exhaust gas turbocharger can be inserted from the turbine side into the bearing lane of the bearing housing 21 and then the compressor wheel can be mounted on the compressor side. After the assembly of this body arrangement is completed, it is balanced with the assembled shaft 23.

[0069] FIG. 6 shows a further exemplary embodiment of the exhaust gas turbocharger 20 of FIG. 4, in which the disk spring 1 shown in FIG. 4 is used with an additional heat shield 4. In this example, the disk spring 1 is arranged along the axial direction A between the bearing housing 21 and the additional heat shield 4.

[0070] It is understood that the foregoing description is that of the exemplary embodiments of the disclosure and that various changes and modifications may be made thereto without departing from the spirit and scope of the disclosure as defined in the appended claims.