FLAP DEVICE

Abstract

A flap device for controlling a gas flow through a pipe comprises a flap that is rotationally fixedly connected to a flap shaft and at least one support unit by means of which the flap shaft is rotatably supported. A radial hollow space that is bounded in an axial direction by respective attachment surfaces is formed between the flap shaft and a reception section of the support unit. A damping element composed of an elastic material is clamped in the hollow space with axial and/or radial deformation and/or preload.

Claims

1. A flap device for controlling a gas flow through a pipe, the flap device comprising: a flap that is rotationally fixedly connected to a flap shaft; and at least one support unit by means of which the flap shaft is rotatably supported, wherein a radial hollow space that is bounded in an axial direction by respective attachment surfaces is formed between the flap shaft and a reception section of the support unit; and wherein a damping element composed of an elastic material is clamped in the hollow space with axial and/or radial deformation and/or preload.

2. The flap device in accordance with claim 1, that is an exhaust gas flap device for an exhaust train of a motor vehicle.

3. The flap device in accordance with claim 1, wherein the damping element is partly or completely produced from a wire mesh or from a fiber material.

4. The flap device in accordance with claim 1, wherein the flap shaft is radially fixed in the reception section by means of at least one support element separate from the damping element.

5. The flap device in accordance with claim 4, wherein the flap shaft is radially fixed with clearance in the reception section.

6. The flap device in accordance with claim 4, wherein the damping element is arranged at a side of the support element remote from the flap axially offset from said support element in the hollow space.

7. The flap device in accordance with claim 4, wherein a step by which the support element is fixed in the axial direction is formed at an inner wall of the hollow space.

8. The flap device in accordance with claim 7, wherein the step by which the support element is fixed in the axial direction is formed in an axial direction facing away from the flap.

9. The flap device in accordance with claim 4, wherein the support element is directly or indirectly supported at the pipe.

10. The flap device in accordance with claim 1, wherein the damping element is supported in a radial direction at an inner side of the reception section and is acted on by a separate tensioning part in an axial tensioning direction.

11. The flap device in accordance with claim 1, wherein the support unit has a bearing bushing which is fastened to the pipe and in which the reception section is formed.

12. The flap device in accordance with claim 1, wherein a sliding element composed of a friction-reducing material is arranged between the flap shaft and the damping element.

13. The flap device in accordance with claim 12, wherein the friction-reducing material is one of graphite and boron nitride.

14. The flap device in accordance with claim 12, characterized in that the sliding element is ring shaped.

15. The flap device in accordance with claim 14, wherein the sliding element is slit in the axial direction.

16. The flap device in accordance with claim 14, wherein the sliding element and the damping element are captively coupled to one another.

17. The flap device in accordance with claim 1, wherein the damping element is rectangular in the axial section and/or circular in the radial section.

18. A method of manufacturing a flap device, the method comprising the steps of: providing a support unit and a flap to be rotatably supported that is rotationally fixedly connected to a flap shaft; introducing the flap shaft into a reception section of the support unit such that a radial hollow space that is bounded in an axial direction by an attachment surface is formed between the flap shaft and the reception section; inserting a damping element composed of an elastic material into the hollow space; acting on the inserted damping element by means of a tensioning element at least in an axial tensioning direction facing toward the attachment surface to clamp the damping element in the hollow space with axial and/or radial deformation and/or preload; and direct or indirect fixing of the tensioning element at the support unit.

Description

[0030] The invention will be described in the following by way of example with reference to the drawings.

[0031] FIG. 1 shows a support unit of a flap device in accordance with the invention in a sectional view;

[0032] FIG. 2 shows a damping element of the support element shown in FIG. 1 in a non-deformed starting state; and

[0033] FIG. 3 shows the damping element in accordance with FIG. 2 in a deformed installed state.

[0034] The flap device in accordance with the invention shown in FIG. 1 comprises a plate-like or disk-like flap 10 that is only shown in part and that is attached to a flap shaft 12. The flap 10 is arranged in a pipe 15 and is rotatably supported about an axis of rotation R by means of a support unit 17. The pipe 15 can be the section of an exhaust gas line or a (tubular) flap housing. A gas flow, for example an exhaust gas flow, led through the pipe 15 can be selectively released and (partly) blocked by rotating the flap 10.

[0035] The support unit 17 comprises a bearing bushing 19 which is fastened to the pipe 15 and in which a reception section 20 for a shaft stub 21 of the flap shaft 12 is formed. The shaft stub 21 is led through a shaft leadthrough 23 of the pipe 15 and is supported in the bearing bushing 19 with clearance by means of an annular support element 25. The flap 10 can be supported at one side. Alternatively, the flap shaft 12 can have two oppositely disposed shaft stubs 21 and can be supported at both sides by means of respective support units 17. One of the shaft stubs can be connected to a drive device to drive the shaft 12.

[0036] As can be recognized in FIG. 1, the support element 25 is directly supported at the pipe 15. In general, the support element 25 could also be supported at the pipe 15 via at least one additional component. In an axial direction 26 facing away from the flap 10, the support element 25 is supported at a step 27 that is provided at an inner wall 28 of a hollow space 30 formed in the bearing bushing 19 radially between the flap shaft 12 and the reception section 20. A damping element 35 composed of an elastic material, preferably of a wire mesh, is furthermore located in the hollow space 30 in the shape of an annular gap.

[0037] The damping element 35 is directly supported at the support element 25 in an axial direction 36 facing toward the flap 10. In the opposite axial direction 26, the damping element 35 is supported at a termination element 37 of the support unit 17 fixed to the bearing bushing 19 at the end side. The damping element 35 is therefore clamped between the support element 25, the termination element 37, and the inner wall 28 and is preloaded both axially and radially. The movements of the flap shaft 12 relative to the pipe 15 and to the bearing bushing 19 that occur during the operation of the flap device are damped by the clamped elastic damping element 35 so that unwanted disturbing noises also do not occur with pronounced pressure pulsations in the pipe 15. Both the elasticity of the clamped damping element 35 and the inner friction contribute to the noise-reducing effect. The temperature resistance of the damping element 35 can be adapted in wide ranges by selection of a corresponding material for the wire mesh. The stiffness of the damping element 35 can also be set to a desired value by the material selection.

[0038] To reduce the friction between the damping element 35 and the flap shaft 12, a coating, not shown, of a friction-reducing material such as graphite or boron nitride can be provided at a radial inner side 40 of the damping element 35. An embodiment, not shown, of the invention, additionally provides a separate sliding ring composed of a friction-reducing material that is arranged between the damping element 35 and the shaft stub 21. The sliding ring can be slit to be able to compensate thermally induced expansion movements of the shaft stub 21 and/or of the bearing bushing 19. The sliding ring and the damping element 35 can be captively coupled to one another by means of one or more geometrical form-fit features.

[0039] The flap 10 is arranged in the pipe 15 and the shaft stub 21 of the flap shaft 12 is led through the shaft leadthrough 23 to manufacture a flap device in accordance with the invention. The support element 25 is placed onto the shaft stub 21 and the bearing bushing 19 is fastened to the pipe 15 to form the support unit 17. The damping element 35 is then introduced into the hollow space 30 in the non-deformed starting state shown in FIG. 2 until it abuts the support element 25. The termination element 37 is subsequently inserted into the hollow space 30. In this respect, the damping element 35 is acted on by a projection 45 of the termination element 37 so that an axial preload takes place. The axial preload is converted by the elastic material of the damping element 35 into a radial preload so that the damping element 35 is also radially clamped in the hollow space 30.

[0040] In the installed state shown in FIG. 3, the damping element 35 is deformed and thus preloaded both in the axial direction and in the radial direction. The fastening of the bearing bushing 19 to the pipe 15 and the fixing of the termination element 37 to the bearing bushing 19 can respectively take place by welding.

[0041] The invention enables a low-noise operation of exhaust gas flaps and of similar flap devices even with a strong gas pressure pulsation in the associated pipe 15.

REFERENCE NUMERAL LIST

[0042] 10 flap [0043] 12 flap shaft [0044] 15 pipe [0045] 17 support unit [0046] 19 bearing sleeve [0047] 20 reception section [0048] 21 shaft stub [0049] 23 shaft leadthrough [0050] 25 support element [0051] 26 axial direction [0052] 27 step [0053] 28 inner wall [0054] 30 hollow space [0055] 35 damping element [0056] 36 axial direction [0057] 37 termination element [0058] 40 inner side [0059] 45 projection [0060] R axis of rotation