MASS DAMPER FOR DAMPING VIBRATIONS OF A STRUCTURE, STRUCTURE WITH SUCH A MASS DAMPER AND METHOD FOR ADJUSTING THE NATURAL FREQUENCY OF A MASS DAMPER

Abstract

The present invention refers to a mass damper for reducing vibrations of a structure with a pendulum mass and a damping means, wherein the mass damper has at least three bearings with which the pendulum mass is movably supported on the structure such that it can execute pendulum movements and each of the bearings has at least one pendulum plate with a concave bearing surface and a sliding shoe arranged movably thereon with a convex counter surface. In accordance with the invention, the bearing surfaces and the associated counter surfaces are curved with a constant radius of curvature R and all bearings have a lowest possible friction between the counter surface and the bearing surface. The invention also extends to a structure with such a mass damper and a method for adjusting the natural frequency of a mass damper, in which the natural frequency of the pendulum mass can be adjusted independently of one another in both main directions by displacing and/or rotating the pendulum plates. The invention also extends to the damping means, which can be implemented with linear viscous passive damping, with square viscous passive damping or with controlled damping, in order to tune this damping together with the friction damping of the bearings to the optimum damping of the mass damper.

Claims

1. A mass damper for reducing vibrations of a structure with a pendulum mass and a damping means, wherein the mass damper has at least three bearings with which the pendulum mass is movably supported on the structure such that it can execute pendulum movements and each of the bearings has at least one pendulum plate with a concave curved bearing surface and a sliding shoe arranged movably thereon with a convex curved counter surface, each sliding shoe for its part is articulately fastened to the pendulum mass, and for all bearings, the bearing surfaces and the associated counter surfaces are curved with a constant radius of curvature and all bearings have a lowest possible friction between the counter surface and the bearing surface, wherein for adjusting the natural frequency of the pendulum mass, for at least two bearings, the relative position of the respective pendulum plates can be changed with respect to one another.

2. The mass damper according to claim 1, wherein the damping means has passive linear viscous damping properties, passive square viscous damping properties and/or controlled damping properties and wherein optionally the mass damper has at least one hydraulic cylinder.

3. The mass damper according to claim 1, wherein at least one bearing has a friction resistance between the counter surface and the bearing surface which is less than 5% of the weight force of the pendulum mass, less than 0.5% of the weight force of the pendulum mass, or less than 0.25% of the weight force of the pendulum mass.

4. The mass damper according to claim 1, wherein the radius of curvature of the bearing surfaces of the pendulum plates corresponds to the required pendulum radius of a freely suspended pendulum mass of the same mass.

5. The mass damper according to claim 1, wherein the bearing surfaces of the pendulum plates and/or the counter surfaces of the sliding shoes are curved cylindrically and/or spherically.

6. The mass damper according to claim 1, wherein for at least one, or optionally each, bearing, the bearing surface and the associated counter surface are curved with the same radius of curvature.

7. The mass damper according to claim 1, wherein at least one bearing has a multi-part pendulum plate, which has a plurality of pendulum plate sections.

8. The mass damper according to claim 7, wherein the pendulum plate sections are strip-shaped with strip-shaped partial bearing surfaces in plain view, of which optionally at least two are arranged at right angles to one another.

9. The mass damper according to claim 8, wherein a sliding shoe with two counter surfaces and a joint being between them is arranged between two, optionally arranged at right angles to one another, strip-shaped pendulum plate sections.

10. The mass damper according to claim 8, wherein for at least one bearing, the pendulum plate sections of the bearing can be displaced and/or tilted relative to one another so that the respective partial bearing surfaces are flush at their upper side after the displacement.

11. The mass damper according to claim 7, wherein for at least one bearing, the pendulum plate sections can be changed in their position relative to one another separately from one another.

12. The mass damper according to claim 7, wherein for adjusting the natural frequency of the pendulum mass, for at least two bearings, the relative position of the respective pendulum plate sections corresponding to one another can be changed with respect to one another.

13. The mass damper according to claim 1, wherein for adjusting the natural frequency, for at least two bearings, the pendulum plates extending longitudinally in the direction of an axis wherein the frequency of the pendulum movement is to be adjusted, can be displaced relative to one another in the direction wherein the axis extends.

14. The mass damper according to claim 1, wherein for adjusting the natural frequency, for at least two bearings, the two pendulum plates can be rotated relative to one another.

15. The mass damper according to claim 14, wherein the rotation takes place about a radius center which is not equal to a radius center of the curved bearing surfaces.

16. The mass damper according to claim 1, wherein at least one bearing is designed as a hydrostatic bearing.

17. The mass damper according to claim 16, wherein at least one bearing designed as a hydrostatic bearing has a pump device generating the hydrostatic effect.

18. The mass damper according to claim 17, wherein at least one bearing designed as a hydrostatic bearing is designed such that it has emergency running properties in the event of failure of the pump device generating the hydrostatic effect.

19. The mass damper according to claim 17, wherein the pump device is designed such that its pumping capacity is controllable for situation-adapted adjusting of the friction of the bearing.

20. The mass damper according to claim 16, wherein at least one bearing designed as a hydrostatic bearing is designed such that it contributes at least temporarily to the damping of the mass damper.

21. The mass damper according to claim 1, wherein the damping means is designed such that its damping force is controllable for adjusting the generation of situation-adapted damping properties.

22. The mass damper according to claim 1, wherein at least one bearing is designed as a rolling bearing or as a rail-guided wheel slide.

23. The mass damper according to claim 22, wherein at least one bearing designed as a rolling bearing or as a rail-guided wheel slide has a sound insulation.

24. The mass damper according to claim 1, wherein it has four bearings with which the pendulum mass is supported on the structure and which are designed such that the position of the pendulum plates can be changed in pairs counter-directed.

25. The mass damper according to claim 1, wherein at least two bearings have a common adjusting device for displacing and/or rotating the respective pendulum plates relative to one another.

26. The mass damper according to claim 25, wherein the adjusting device has at least one wedge, a lining plate, an eccentric, a pendulum rod and/or an inversely curved calotte for rotating the pendulum plate.

27. The mass damper according to claim 25, wherein the adjusting device has a motor drive means for displacing and/or rotating the pendulum plates.

28. A structure with a mass damper according to claim 1, wherein the damping means and the pendulum plates of the bearings of the mass damper are attached to the structure.

29. A method for adjusting the natural frequency of a mass damper according to claim 1, wherein the pendulum plates of the bearings of the mass damper are displaced in a first direction and/or rotated relative to one another until the natural frequency of the pendulum movement of the pendulum mass occurring in this first direction reaches a predetermined target value.

30. The method for adjusting the natural frequency of a mass damper according to claim 29, wherein the pendulum plates of the bearings of the mass damper are displaced in a second direction and/or rotated relative to one another until the natural frequency of the pendulum movement of the pendulum mass occurring in this second direction reaches a predetermined target value.

31. The method for adjusting the natural frequency of a mass damper according to claim 29, wherein the pendulum plates of the bearings of the mass damper are pushed towards one another and/or rotated inwards in order to increase the natural frequency of the pendulum mass.

32. The method for adjusting the natural frequency of a mass damper according to claim 29, wherein the pendulum plates of the bearings of the mass damper are pushed apart one another and/or rotated outwards in order to reduce the natural frequency of the pendulum mass.

Description

[0053] In the following, the invention will be explained in more detail on the basis of embodiments shown in the drawings or figures. These show schematically:

[0054] FIG. 1: a side view of a first embodiment in which the sliding shoes are centered above the pendulum plate, respectively;

[0055] FIG. 2: a top view of the first embodiment shown in FIG. 1;

[0056] FIG. 3: a top view of a second embodiment with four pendulum plates in cross slide-like design;

[0057] FIG. 4: the embodiment shown in FIG. 1, in which the natural frequency of the pendulum mass is reduced by pushing the two pendulum plates apart one another;

[0058] FIG. 5: the embodiment shown in FIG. 1 or FIG. 4, in which the natural frequency of the pendulum mass is increased by pushing the pendulum plates towards one another;

[0059] FIG. 6: an embodiment of a hydrostatic bearing for use in a mass damper according to the invention;

[0060] FIG. 7: a top view of the counter surface of the sliding shoe with lubrication channels and lubrication holes;

[0061] FIG. 8: an embodiment of a bearing designed as a rolling bearing for the mass damper in accordance with the invention;

[0062] FIG. 9: a third embodiment of a mass damper according to the invention with an adjusting device for mutual rotation of the pendulum plates of the bearings by means of two wedges;

[0063] FIG. 10: a fourth embodiment of a mass damper according to the invention with an eccentric under the pendulum plates of the bearings for rotating the pendulum plates;

[0064] FIG. 11: a fifth embodiment of a mass damper according to the invention with an adjusting device having an inversely curved calotte for rotating the pendulum plate in each of the bearings;

[0065] FIG. 12: another embodiment of an adjusting device for a pendulum plate in which the adjusting device comprises a plurality of variable-length pendulum rods; and

[0066] FIG. 13: an embodiment of an adjusting device for a pendulum plate using lining plates;

[0067] In the figures, identical reference numerals designate similar components even if they are used in different embodiments.

[0068] FIG. 1 shows a mass damper 1 according to the invention for reducing vibrations of a structure 2 with a pendulum mass 3 and a damping means 4. The damping means 4 is arranged between the pendulum mass 3 and the structure 2, so that the damping means 4 can work with respect to the relative movement between the pendulum mass 3 and the structure 2. Basically, a mass damper 1 according to the invention has at least three bearings 5. As can be seen in FIG. 2, the mass damper 1 shown here has four such bearings 5 on which it stands in the structure 2 on a floor of the structure 2. As already mentioned, three bearings 5 are sufficient for the basic mode of operation of the mass damper according to the invention, especially since the pendulum mass 3 is then simply statically determined supported.

[0069] The bearings 5 for their part are designed such that they support the pendulum mass 3 on the structure 2 movably so that the pendulum mass 3 can execute pendulum movements. Each of the bearings 5 has at least one pendulum plate 6 with a concave curved bearing surface 7 and a sliding shoe 8 arranged movably thereon with a convex curved counter surface 9. Each of the sliding shoes 8 for its part is articulately fastened to the pendulum mass 3.

[0070] In accordance with the invention, for all bearings 5, the bearing surfaces 7 and the associated counter surfaces 9 are curved with a constant radius of curvature R. This radius of curvature R refers to a virtual center of rotation M around which an object moving on the curved bearing surface 7 would move. In this case, this is the sliding shoe 8 of the respective bearing 5.

[0071] The arrangement of the pendulum plates 6 below the pendulum mass 3, as can be seen in FIG. 1 or FIG. 2, is a starting position as it would normally be used when mounting the mass damper 1 in the structure 2. Since the sliding shoes 8 stand central on the pendulum plate 6 or the bearing surface 7. This can also be seen from the fact that the distance between the center points of the sliding shoes or the center points of the counter surface 9 (drawn in the figure as distance a1 below the structure) corresponds to the distance between the two centers of rotation M of the two curved bearing surfaces 7 (drawn in the drawing as distance a2 above the pendulum mass 3). So, distances a1 and a2 are equal. This means that the center of gravity S of the pendulum mass 3 moves on a circular path with the radius RS, which is equal to the radius R of the curvature of the bearing surfaces 7.

[0072] The sliding shoes 8 each have counter surfaces 9 with a radius of curvature corresponding to that of the bearing surfaces 7, so that the sliding shoes 8 rest flat on the bearing surface 7. Thus, for all bearings 5, the bearing surfaces 7 and the associated counter surfaces 9 are curved with a constant radius of curvature in an exactly matched manner. In this way, the pendulum mass 3 can then perform a pendulum movement in a direction lying in plan view, which is indicated by x in FIG. 2.

[0073] According to the invention, it is important that all bearings 5 have as little friction as possible between the counter surface 9 and the bearing surface 7. The actual damping is effected via the damping means 4, which can be designed in any way, for example as a hydraulic cylinder (oil damper).

[0074] If the friction of the bearings 5 is negligibly small, the damping means 4 is designed such that it generates a linear viscous damping, which is tuned to the optimum value of the mass damper 1. If the friction of the bearings 5 is not negligibly small, the damping means 4 is designed for square viscous damping. Advantageously, this is done so that the entire damping of the mass damper in the amplitude range of the pendulum displacement of 20% to 80% of the maximum displacement amplitude is approximately linear and tuned to the optimum value. The damping of the damping means 4 or any hydraulic cylinders and/or the lubricant supply for hydrostatic bearings can also be controlled in real time in order to achieve a certain damping behavior as a function of the displacement amplitude of the pendulum mass.

[0075] In the case of a pendulum direction provided in a single direction, such as the x-direction indicated in FIG. 2, it is sufficient if the radius of curvature R of the bearing surfaces 7 of the pendulum plates 6 and/or the counter surfaces 9 of the sliding shoes 8 have a cylindrical (circular) curvature. However, if the mass damper 1 is to be able to perform pendulum movements of a spatial nature, i.e. also be effective in any direction and also be adjustable in its natural frequency in both main directions, one possibility is to form the bearing surfaces 7 of the oscillating plates 6 and the counter surfaces 9 of the sliding shoes 8 spherically (globularly). The bearing 5 can have a multi-part pendulum plate 7, as can be seen for example in FIG. 3. Here there are several strip-shaped pendulum plate sections 10 in plan view, all of which have spherically curved surfaces. They therefore have strip-shaped partial bearing surfaces on their surface, which in turn have a spherical curvature. Since all pendulum plate sections 10 and the strip-shaped partial bearing surfaces arranged on them thus have the same radius of curvature in both the x- and y-directions, it is now possible to arrange the strip-shaped partial bearing surfaces 10 at right angles to one another. The result is a multi-part pendulum plate 7 with a cross slide-like design. This has the advantage that it is considerably cheaper to produce than a pendulum plate 6 with a full surface spherical section or shell-like design.

[0076] However, if the pendulum plate sections 10 are only cylindrically curved (not shown here), the pendulum mass 3 can only be moved in one direction. To actually ensure this movement in the direction, guides must be arranged at the pendulum mass 3 or at the bearings 5 to ensure that the sliding shoes 8 of the bearings 5 do not slip off the pendulum plates 6.

[0077] If now the natural frequency of the pendulum mass 3 is to be adjusted, this is done according to the invention by displacing the pendulum plate 6 or the strip-shaped pendulum plate sections 10 of the bearings 5 apart or towards one another in the direction of the pendulum movement in whose axis the natural frequency is to be adjusted. This is indicated in FIG. 4. Here the two pendulum plates 6 are displaced apart one another. This causes the center of rotation of the respective bearing surface 7 to move outwards, so that the distance a2 becomes greater than the distance a1, as can be seen from the comparison of FIG. 1 with FIG. 4. Thus, the displacement causes a frequency adjustment in a very simple but effective way, whereby the displacement leads to the fact that the pendulum radius RS of the center of gravity S of the pendulum mass 3 is now larger than the radius of the bearing surface 7. As a result, the natural frequency decreases.

[0078] If the natural frequency is to be increased in the x-direction compared to the starting position shown in FIG. 1, according to the invention, this is done by pushing the pendulum plates 7 or the strip-shaped pendulum plate sections 10 inwards, as can be seen in FIG. 5. The result is that the radius RS of the trajectory of the center of gravity S of the pendulum mass 3 is reduced in comparison to the curvature of the pendulum plates 7.

[0079] The frequency adjustments shown in FIG. 4 or FIG. 5 can be carried out in any pendulum direction. In the cross slide-like configuration shown in FIG. 3 with multi-part pendulum plates 7 with several strip-like pendulum plate sections 10, a frequency adjustment can be carried out separately in x- and y-direction and in each direction both for increasing and decreasing the natural frequency of the pendulum mass 3. Since the partial bearing surfaces located on the pendulum plate sections 10 always have the same radius of curvature, it is also possible to ensure a flush arrangement of the bearing surface by simply displacing the pendulum plate sections 10 laterally along the other pendulum plate sections 10 orthogonally aligned to them. This prevents any protrusions or the like in the bearing surface 7.

[0080] As already explained, according to the invention, it is important that the bearings 5 have as little friction as possible in the bearing surfaces 7. One way of ensuring extremely low starting friction is to design the bearing as a hydrostatic bearing, as illustrated in FIG. 6. Such a bearing 5 has a pump device 11 with which liquid lubricant is forced into a sliding plate 19 via a channel 18 and then into the actual sliding gap between the bearing surface 7 and the counter surface 9 via holes 20. Thus, the sliding plate 19 or the sliding shoe 8 floats practically on a lubricant film, which then leads to an extremely low coefficient of friction in the bearing surface 7. It can make sense to control the pump power in real time depending on the wind load, e.g. to generate an even lower coefficient of friction at lowest wind loads for maximum effect of the mass damper 1 or to generate a significantly higher coefficient of friction at earthquake excitation, to additionally decelerate the pendulum mass 3 and thus avoid an impact of the pendulum mass 3 in the walls of the TMD chamber, or to obtain a certain friction behavior as a function of the displacement amplitude of the pendulum mass 3.

[0081] Alternatively or in addition to the pump device 11, a pressure cartridge or a pressurized lubricant reservoir 21 can also be provided at the bearing 5.

[0082] Furthermore, the sliding shoe 8 can have a further joint, which also has a perforated sliding plate, which is also connected to the lubricant circuit via corresponding channels 18. Advantageously, this second sliding plate 22 has a smaller radius of curvature than, for example, the counter surface 9, which is important for the pendulum movement. In the example shown here, there is a third sliding plate 23, which is also connected to the lubricant circuit via channels 18.

[0083] As can be seen in FIG. 7, the sliding plate 19 of the sliding shoe 8 does not only have holes 20. Rather, it is also possible that in addition to the holes 20 in the sliding plate 19 notches or elongate recesses 24 are provided, which can also serve to distribute lubricant. It also has a circumferential seal 25 to prevent the lubricant from exiting the side of the sliding plate 19.

[0084] As an alternative to a hydrostatic bearing, a bearing 5 designed as a rolling bearing can also be used. Such a bearing is shown, for example, in FIG. 8 in a side view. This also has a pendulum plate 6 with a concave curved bearing surface 7. However, a series of rolling elements 31 are further arranged here in the bearing surface 7. For this purpose, advantageously, the rolling elements 31 are arranged in corresponding cages, which in turn have a curvature corresponding to the bearing surface 7. The sliding shoe 8 then runs on these rolling elements 31.

[0085] As an alternative to the displacement of the pendulum plates 6 or the strip-shaped pendulum plate sections 10, they can be rotated or tilted in the plane of the pendulum movement. An example of how this rotation or tilting can be carried out structurally is given in FIG. 9, in which a wedge 13 is arranged under each pendulum plate 6. It is important that the two pendulum plates 6 are tilted in the same way by the angle of rotation α so that a wedge 13 of the same dimension is inserted under each of the two pendulum plates 6. Tilting the pendulum plates 6 outwards causes the centers of curvature M of the bearing surfaces 7 to move outwards in relation to the starting position. This is by the amount by which the pendulum plate 6 is tilted. This amount is shown here as the angle α in FIG. 9. As you can see accordingly, the tilting of the pendulum plates 6 leads to the fact that displacing the rotation centers M apart one another leads to a larger distance a2 between the two centers M compared to the starting situation shown in FIG. 1. Rotating the pendulum plates 6 outwards therefore reduces the frequency of the pendulum movement in the x-direction. If the wedges 13 are arranged just the other way round (not shown), this causes an increase of the natural frequency of the pendulum mass 3.

[0086] As an alternative to the wedges 13, it can also be used eccentrics 14 arranged under the pendulum plates 6 with an eccentric upper part 26 and an eccentric lower part 27, as shown in FIG. 10. The angle α with which the bearing surface 7 or the pendulum plate 6 is rotated outwards can be adjusted by rotating the upper eccentric part 26 relative to the lower eccentric part 27.

[0087] FIG. 11 shows another variant with which the bearing surface 7 or the pendulum plate 6 can be rotated. Here, inversely curved calottes 15 are arranged under the pendulum plates 6, on which the bearing plates 6 sit. So that these bearing plates 6 sit firmly on the inversely curved calottes 15, their underside has a curvature which is correspondingly negative or convex to that of the calottes 15. If the bearing surface 7 or the pendulum plate 6 is to be rotated, this can now be done by displacing the inverted calotte 15 laterally, as indicated by the horizontal double arrow 28.

[0088] A further variant of the adjustment of the angular position of the pendulum plate 6 is shown in FIG. 12. Here the pendulum plate 6 rests on a plurality of pendulum rods 16, at least some of which can be changed in length. These variable-length pendulum rods are assigned to the reference numeral 29 and are arranged in particular on the outer sides of the pendulum plate 6. Thus, the pendulum plate 6 can be tilted around the center by changing the variable-length rods 29.

[0089] FIG. 13 schematically shows a further variant for changing the angular position of the sliding plate 6. Here there is a row of lining plates 17 below the pendulum plate 6. There is another joint element 30 between the lining plates 17 and the pendulum plate 6, which ensures that the connection between the lining plates 17 and the curved pendulum plate 6 is fully made. The pendulum plate 6 can be tilted by removing or inserting further lining plates 17 into the stack of lining plates.

Reference Numerals

[0090] 1 Mass damper [0091] 2 Structure [0092] 3 Pendulum mass [0093] 4 Damping means [0094] 5 Bearing [0095] 6 Pendulum plate [0096] 7 Bearing surface [0097] 8 Sliding shoe [0098] 9 Counter surface [0099] 10 Strip-shaped pendulum plate section [0100] 11 Pump device [0101] 12 Adjusting device [0102] 13 Wedge [0103] 14 Eccentric [0104] 15 Inverted calotte [0105] 16 Pendulum rod [0106] 17 Lining plate [0107] 18 Lubricant channel [0108] 19 Sliding plate [0109] 20 Hole for lubricant [0110] 21 Lubricant reservoir/pressure cartridge [0111] 22 Second sliding plate of the sliding shoe [0112] 23 Third sliding plate of the sliding shoe [0113] 24 Elongate recesses in sliding plate 19 [0114] 25 Lateral seal [0115] 26 Eccentric upper part [0116] 27 Eccentric lower part [0117] 28 Movement arrow for displacement of the calottes [0118] 29 Variable-length pendulum rods [0119] 30 Joint element [0120] 31 Rolling element [0121] R Radius of the bearing surface [0122] RS Pendulum radius of the center of mass [0123] S Center of gravity of the pendulum mass [0124] M Center of curvature of the bearing surface [0125] a1 Average distance between the sliding shoes [0126] a2 Distance between the points M [0127] x First direction [0128] y Second direction [0129] α Angle of rotation