Damper
The present disclosure relates to a frequency tuned damper having a vibration body ( 19 ) and at least one elastic element ( 11, 13, 15, 17 ) which connects the vibration body to a surface ( 21 ), the vibrations of which is to be dampened. The elastic element has a wide portion ( 29 ) and a narrow portion ( 31 ) disposed at different locations on an axis ( 39 ) which is substantially parallel with the normal of the surface. The wider portion has a cavity ( 41 ), and the wide and narrow portions are inter-connected by a transition portion ( 43 ). The part of the narrow portion that is closest to the transition portion fits inside the cavity, as seen in the direction of the axis, such that the narrow portion can be pushed at least partly into the cavity, thereby flexing the transition portion.
1. A dampening system comprising:
a vibration surface, wherein the vibration surface experiences vibrations parallel to the vibration surface and vibrations normal to the vibration surface;
a vibration body; and
at least one elastic element which connects the vibration body to the vibration surface such that the vibration body forms an elastically suspended mass, the elastic element having a wide portion and a narrow portion disposed at different locations along a longitudinal axis which is substantially parallel with a normal of the vibration surface, one of said portions being adapted to attach the elastic element to the vibration body and the other to attach the elastic element to the vibration surface, the wide portion having a cavity, wherein
the wide and narrow portions are inter-connected by a transition portion,
a maximum radial extension of the narrow portion is smaller than a minimum radial extension of the cavity, such that the narrow portion can be pushed at least partly into the cavity of the wide portion, thereby flexing the transition portion, and
the elastic element and the vibration body are tuned to said vibrations of the vibration surface such that the vibrations parallel with the vibration surface and the vibrations normal to the vibration surface are counteracted through phase-shifted movement of the vibration body.
2. The system according to claim 1 , wherein said at least one elastic element is circular symmetric about the longitudinal axis.
3. The system according to claim 1 , wherein the transition portion has the shape of an annular disc, centered with respect to the longitudinal axis.
4. The system according to claim 1 , wherein the transition portion has the shape of an envelope surface of the frustum of a cone, centered with respect to the longitudinal axis.
5. The system according to claim 1 , wherein the cavity is open in the direction of the longitudinal axis at the wide portion.
6. The system according to claim 1 , wherein the cavity extends into the narrow portion of the elastic element.
7. The system according to claim 1 , wherein the elastic element is made of silicone rubber.
8. The system according to claim 1 , wherein the elastic element is attached to the vibration body by means of a first circumferential groove in the elastic element engaging with a circumferential projection inside a cavity of the vibration body.
9. The system according to claim 8 , wherein the elastic element comprises a second circumferential groove for attaching the elastic element to the vibration surface.
10. The system according to claim 1 , wherein a mass of the vibration body, a stiffness of the elastic element, and a damping of the elastic element are selected to cause the vibration body to oscillate at a predetermined target frequency normal to the vibration surface.
11. A method of providing a frequency tuned damper attachable to a vibration surface for damping vibrations of the vibration surface, said vibrations including vibrations parallel to the vibration surface and vibrations normal to the vibration surface, said method comprising:
providing a vibration body; and
providing at least one elastic element which is adapted to connect the vibration body to the vibration surface such that the vibration body forms an elastically suspended mass, the elastic element having a wide portion and a narrow portion disposed at different locations along a longitudinal axis which is substantially parallel with the normal of the vibration surface when the damper is mounted, one of said portions being adapted to attach the elastic element to the vibration body and the other to attach the elastic element to the vibration surface, the wide portion having a cavity, wherein
the wide and narrow portions are inter-connected by a transition portion,
a maximum radial extension of the narrow portion is smaller than a minimum radial extension of the cavity, such that the narrow portion can be pushed at least partly into the cavity of the wide portion, thereby flexing the transition portion, and
the elastic element and the vibration body are tuned to said vibrations such that vibrations parallel with the vibration surface and vibrations normal to the vibration surface are counteracted through phase-shifted movement of the vibration body.
12. The method according to claim 11 , wherein said at least one elastic element is circular symmetric about the longitudinal axis.
13. The method according to claim 12 , wherein the transition portion has the shape of an annular disc, centered with respect to the longitudinal axis.
14. The method according to claim 12 , wherein the transition portion has the shape of an envelope surface of the frustum of a cone, centered with respect to the longitudinal axis.
15. The method according to claim 12 , wherein the cavity is open in the direction of the longitudinal axis at the wide portion.
16. The method according to claim 12 , wherein the cavity extends into the narrow portion of the elastic element.
17. The method according to claim 12 , wherein the elastic element is made of silicone rubber.
18. The method according to claim 11 , wherein the transition portion has the shape of an annular disc, centered with respect to the longitudinal axis.
19. The method according to claim 18 , wherein the cavity is open in the direction of the longitudinal axis at the wide portion.
20. The method according to claim 18 , wherein the cavity extends into the narrow portion of the elastic element.
21. The method according to claim 11 , wherein the transition portion has the shape of an envelope surface of the frustum of a cone, centered with respect to the longitudinal axis.
22. The method according to claim 21 , wherein the cavity is open in the direction of the longitudinal axis at the wide portion.
23. The method according to claim 21 , wherein the cavity extends into the narrow portion of the elastic element.
24. The method according to claim 11 , wherein the cavity is open in the direction of the longitudinal axis at the wide portion.
25. The method according to claim 24 , wherein the cavity extends into the narrow portion of the elastic element.
26. The method according to claim 11 , wherein the cavity extends into the narrow portion of the elastic element.
27. The method according to claim 11 , wherein the elastic element is made of silicone rubber.
28. The method according to claim 11 , wherein the elastic element is attached to the vibration body by means of a first circumferential groove in the elastic element engaging with a circumferential projection inside a cavity of the vibration body.
29. The method according to claim 28 , wherein the elastic element comprises a second circumferential groove for attaching the elastic element to the vibration surface.
30. The method according to claim 11 , wherein a mass of the vibration body, a stiffness of the elastic element, and a damping of the elastic element are selected to cause the vibration body to oscillate at a predetermined target frequency normal to the vibration surface.