VIBRATION DAMPER MADE UP OF SPOKE SPRING ABSORBERS

Abstract

A vibration damper with at least two absorbers, each having at least one spoke spring, enables efficient damping of the frequency response of a crankshaft. The absorbers preferably have different natural frequencies that are adapted to the frequency response of the crankshaft. The absorbers exhibit a frequency response, which is not or only insignificantly dependent on aging of the spoke springs and on the ambient temperature. The corresponding vibration dampers can be easily designed and mounted.

Claims

1. A vibration damper for damping torsional vibrations, which is rotatable about an axis of rotation, the vibration damper comprising: at least two absorbers, each said absorber having a natural frequency and at least one spoke spring having the natural frequency of the absorber, each of the at least one spoke spring including; a circular ring-shaped outer element radially on an outside; a connecting element configured to connect to a shaft radially on an inside; and a plurality of spokes extending in a radial direction between the circular ring-shaped outer element and the connecting element and the spokes are elastic; and wherein the at least two absorbers have different natural frequencies from one another.

2. The vibration damper according to claim 1, wherein the at least two absorbers comprises at least three of the absorbers each having different natural frequencies from one another.

3. The vibration damper according to claim 1, wherein one of the at least two absorbers comprises a plurality of the spoke springs each having the natural frequency of the absorber.

4. The vibration damper according to claim 1, wherein the natural frequencies of all of the absorbers differ from one another.

5. The vibration damper according to claim 1, wherein the spoke springs comprise torsion spring bars.

6. The vibration damper according to claim 1, wherein the spoke springs are arranged one behind another in a direction of the axis of rotation, and the spoke springs adjacent to one another in the direction of the axis of rotation are in contact.

7. A vibration damper for damping a vibration behavior of a crankshaft system having a crankshaft natural frequency, the vibration damper comprising the vibration damper according to claim 1, wherein a first one of the at least two absorbers has a first said natural frequency and a second one of the at least two absorbers has a second said natural frequency, and the first natural frequency is below the crankshaft natural frequency and the second natural frequency is above the crankshaft natural frequency.

8. A vibration damper for damping a vibration behavior of a crankshaft system having a crankshaft natural frequency, the vibration damper comprising the vibration damper according to claim 1, wherein a first one of the at least two absorbers has a first natural frequency, which deviates by at most 10 Hz from the crankshaft natural frequency, a second one of the at least two absorbers has a second natural frequency, which deviates by at most 20 Hz from a frequency of a maximum of a frequency response of the crankshaft system damped by the first absorber.

9. The vibration damper according to claim 7, wherein the at least two absorbers comprises a further absorber having a further said natural frequency, the further natural frequency of the further absorber deviates by at most 20 Hz from a frequency of a maximum of a frequency response of the crankshaft system damped by the at least two absorbers.

10. A kit comprising: a crankshaft having a crankshaft natural frequency and the vibration damper according to claim 1, wherein a first of the at least two absorbers has a first said natural frequency which is below the crankshaft natural frequency and a second of the at least two absorbers has a second natural frequency which is above the crankshaft natural frequency.

11. A vibration damper for damping torsional vibrations, the vibration damper comprising: first and second absorbers, each of the first and second absorbers having a respective first and second natural frequency, with the first natural frequency being different than the second natural frequency, each of the first and second absorbers comprising a spoke spring including; a ring-shaped outer element radially on an outside; a connecting element radially on an inside; and a plurality of spokes extending in a radial direction between the ring-shaped outer element and the connecting element and the spokes are elastic.

12. The vibration damper according to claim 11, further comprising a third absorber including at least one of the plurality of spoke springs and having a third natural frequency, and the first, second, and third natural frequencies are different than one another.

13. The vibration damper according to claim 11, wherein at least one of the first or second absorbers comprises a plurality of the spoke springs each having the natural frequency of the absorber.

14. The vibration damper according to claim 11, wherein the natural frequencies of all of the absorbers differ from one another.

15. The vibration damper according to claim 11, wherein the spoke springs comprise torsion spring bars.

16. The vibration damper according to claim 11, wherein the spoke springs are arranged one behind another in a direction of an axis of rotation, and the spoke springs adjacent to one another in the direction of the axis of rotation are in contact.

17. A vibration damper for damping a vibration behavior of a crankshaft system having a crankshaft natural frequency, the vibration damper comprising the vibration damper according to claim 11, wherein the first natural frequency is below the crankshaft natural frequency and the second natural frequency is above the crankshaft natural frequency.

18. The vibration damper according to claim 17, further comprising a Further absorber including at least one of the plurality of spoke springs and having a further natural frequency, the further natural frequency of the further absorber deviates by at most 20 Hz from a frequency of a maximum of a frequency response of the crankshaft system damped by the first and second absorbers.

19. A vibration damper for damping a vibration behavior of a crankshaft system having a crankshaft natural frequency, the vibration damper comprising the vibration damper according to claim 11, wherein the first natural frequency deviates by at most 10 Hz from the crankshaft natural frequency, the second natural frequency deviates by at most 20 Hz from a frequency of a maximum of a frequency response of the crankshaft system damped by the first absorber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Both the disclosure and the technical field are explained in more detail below with reference to the figures. It should be noted that the disclosure is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the substantive matter outlined in the figures and to combine them with other components and knowledge from the present description and/or figures. In particular, it should be noted that the figures and in particular the proportions shown are only schematic in nature. Identical reference symbols indicate the same objects, so that explanations from other figures can also be used. In the figures:

[0023] FIG. 1: shows a first vibration model, which is not part of the disclosure;

[0024] FIG. 2: shows the frequency response of the first vibration model;

[0025] FIG. 3: shows the vibration model of a first example of a vibration damper made up of two absorbers;

[0026] FIG. 4: shows the frequency response of the first example of a vibration damper;

[0027] FIG. 5: shows the vibration model of a second example of a vibration damper made up of five absorbers;

[0028] FIG. 6: shows the frequency response of the second example of a vibration damper; and

[0029] FIGS. 7 and 8: show a third example of a vibration damper in a perspective view and as a cross-section.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a first vibration model for an example not covered by the disclosure. This comprises a crankshaft system 1 representing the crankshaft of an internal combustion engine and associated vibrating masses. The internal combustion engine (not shown) generates a torque 2, which is fed into the crankshaft system 1. In a known manner, this torque is frequency-dependent and the frequency response of the crankshaft system 1 is also frequency-dependent with a natural or resonant frequency. FIG. 2 shows the frequency response of this crankshaft system 1 as the crankshaft frequency response 3, which shows a vibration amplitude A of the crankshaft as a function of the rotation frequency f. The crankshaft system 1 has a single crankshaft natural frequency 4, at which the single maximum 5 of the crankshaft frequency response 3 is correspondingly located.

[0031] FIG. 1 further shows a first absorber 6, which is designed as a spoke spring absorber with a spoke spring. Spoke spring absorbers are described in detail below with reference to FIGS. 7 and 8. They have an outer circular ring-like element and an inner connecting element for connecting to the crankshaft, which are connected by radially extending elastically deformable spokes. Based on the design of the spoke spring absorber, in particular by determining the mass of the outer element, the radius of the outer element and/or the number and/or spring constant (thickness) of the spokes, the natural frequency of the first absorber 6 can be determined. The first absorber 6 forms a vibrating system 7, the vibration behavior of which is determined by the first absorber 6. The natural frequency of the first absorber 6 is therein tuned to the crankshaft natural frequency 4.

[0032] If the vibrating system 7 is now connected to the crankshaft system 1 in which the connecting element of the first absorber 6, which is not shown, is connected to the crankshaft in a non-rotatable manner, these together form a first damped crankshaft system 8 with the first crankshaft system frequency response 9 shown in FIG. 2. This frequency response of the first damped crankshaft system 8 has a first maximum 10 and a second maximum 11, which are located at frequencies that are below the crankshaft natural frequency 4 for the first maximum 10 and above the crankshaft natural frequency 4 for the second maximum 11. The vibration amplitude A of the first maximum 10 and the second maximum 11 are significantly lower than the vibration amplitude A of the maximum 5 of the crankshaft frequency response 3. The crankshaft frequency response 3 shown in FIG. 2 is the frequency response of the pure crankshaft system 1 without absorbers.

[0033] In the following FIGS. 3 to 6, two examples of vibration dampers according to the disclosure are explained. The corresponding vibration models are shown in FIGS. 3 and 5, the associated frequency responses are shown in FIGS. 4 and 6. FIGS. 4 and 6 each show the first crankshaft system frequency response 9 of FIG. 2 for comparison.

[0034] FIG. 3 shows a vibration model of a first example of a first vibration damper 13 made up of the first absorber 6 and a second absorber 12. The first absorber 6 corresponds to the first absorber 6 of FIG. 1. The second absorber 12 is also designed as a spoke spring absorber. Its natural frequency is therein tuned to the frequency of the first maximum 10 of FIG. 2, i.e. to the frequency of the higher maximum of the first crankshaft frequency response 9. The first vibration damper 13 is connected to the crankshaft, which is not shown, by connecting the connecting elements, which are not shown, of the first absorber 6 and the second absorber 12, so that the vibration damper 13 is connected to the crankshaft system 1, which together form the second damped crankshaft system 14.

[0035] The second damped crankshaft system 14 exhibits a second crankshaft system frequency response 15, as shown in FIG. 4. This exhibits, in addition to a second maximum 11 corresponding to the second maximum 11 of the first crankshaft system frequency response 9, a third maximum 16 and a fourth maximum 17, wherein the third maximum 16 is at a frequency f below the frequency f of the first maximum 10 and the fourth maximum 17 is at a frequency f above the frequency of the first maximum 10. The amplitudes A of the third maximum 16 and the fourth maximum 17 are smaller here than the amplitude A of the first maximum 10 of the first crankshaft system frequency response 9. This shows that the use of a vibration damper 13 with a plurality of absorbers 6, 12 designed as spoke spring absorbers can achieve good damping of the crankshaft system 1.

[0036] FIG. 5 shows a vibration model of a second example of a second vibration damper 18 comprising a first absorber 6 and a second absorber 12, each designed as described above. Furthermore, the second vibration damper 18 comprises a third absorber 19, a fourth absorber 20, and a fifth absorber 21, each of which is designed as a spoke spring absorber. In FIG. 5, the natural frequencies of the undamped crankshaft system 1 (here 525 Hz) and the natural frequencies of the first absorber 6 (400 Hz), the second absorber 12 (450 Hz), the third absorber 19 (500 Hz), the fourth absorber 20 (560 Hz) and the fifth absorber 21 (620 Hz) are indicated in each case. When the second vibration damper 18 is connected to the crankshaft system 1, a third damped crankshaft system 22 is formed. The corresponding third crankshaft system frequency response 23, in addition to the curve of the first crankshaft system frequency response 9 serving as a reference curve, is shown in FIG. 6. Accordingly, the third crankshaft system frequency response 23 exhibits six maxima 24 extending over frequencies from below the lowest natural frequency of an absorber 6, 12, 19, 20, 21 (here 400 Hz) to above the highest natural frequency of an absorber 6, 12, 19, 20, 21 (here 620 Hz). The amplitude A of the maxima 24 is significantly lower than the amplitude of the first maximum 10 and the second maximum 11, such that significant damping of the crankshaft vibrations occurs here.

[0037] FIGS. 7 and 8 show an example of a third vibration damper 25 in a perspective view (FIG. 7) and as a sectional view (FIG. 8). These two figures are described together in the following, unless explicitly stated otherwise, so that the explanations refer to both figures. In the present example, the third vibration damper 25 is made up of three absorbers: a first absorber 6, a second absorber 12, and a third absorber 19. Each absorber 6, 12, 19 is, in turn, made up of three identical spoke springs, the first absorber 6 being made up of three identical first spoke springs 29, the second absorber 12 being made up of three identical second spoke springs 30 and the third absorber 19 being made up of three identical third spoke springs 31, as shown, in particular, in FIG. 8.

[0038] The spoke spring absorbers are each formed from a circular ring-like outer element 26, an inner connecting element 27 and spokes 28 extending radially between them, which for the sake of clarity are only partially indicated with reference symbols. The spokes 28 are designed as torsion spring bars here. The spoke springs 29, 30, 31 adjacent in the direction of an axis of rotation 32 of the absorbers 6, 12, 19 are in contact with one another, so that in the event of a deflection of an absorber 6, 12, 19, the movement is damped here by the friction present.

[0039] The natural frequency of an absorber 6, 12, 19 and, in general, of a spoke spring absorber can be influenced by changing the corresponding outer element 26, in particular by changing the mass and/or the radius of the outer element 26 and/or by changing the spokes 28, in particular by changing the number of spokes 28 and/or the spring constant of the spokes 28. In the present example, the first absorbers 6, the second absorbers 12 and the third absorbers 19 each differ in their outer elements 26, which have different expansions in the radial direction relative to the axis of rotation 32 and different masses, resulting in different mass moments of inertia of the outer elements 26 of the different spoke springs 29, 30, 31. In this example, the spokes 28 of the spoke springs 29, 30, 31 of the absorbers 6, 12, 19 are identical in number, position and design. The connecting elements 27 connect the absorbers 6, 12, 19 to the crankshaft, which is not shown.

[0040] The absorbers 6, 12, 19 in the third vibration damper 25 are connected by rolling bodies 33, which allow a relative movement against one another. For this purpose, corresponding elongated holes are formed in the outer elements 26, which allow a relative movement of the absorbers 6, 12, 19 against one another.

[0041] The structure of a vibration damper 13, 18, 25 proposed here with at least two absorbers 6, 12, 19, 20, 21, each comprising at least one spoke spring 29, 30, 31, enables efficient damping of the frequency response of a crankshaft. In this regard, the absorbers 6, 12, 19, 20, 21 preferably have different natural frequencies that are adapted to the frequency response of the crankshaft. The absorbers 6, 12, 19, 20, 21 exhibit a frequency response, which is not or only insignificantly dependent on aging of the spoke springs 29, 30, 31 and on the ambient temperature. The corresponding vibration dampers 13, 18, 25 can be easily designed and mounted.

LIST OF REFERENCE SYMBOLS

[0042] 1 Crankshaft system [0043] 2 Torque [0044] 3 Crankshaft frequency response [0045] 4 Crankshaft natural frequency [0046] 5 Maximum [0047] 6 First absorber [0048] 7 Vibrating system [0049] 8 First damped crankshaft system [0050] 9 First crankshaft system frequency response [0051] 10 First maximum [0052] 11 Second maximum [0053] 12 Second absorber [0054] 13 First vibration damper [0055] 14 Second damped crankshaft system [0056] 15 Second crankshaft system frequency response [0057] 16 Third maximum [0058] 17 Fourth maximum [0059] 18 Second vibration damper [0060] 19 Third absorber [0061] 20 Fourth absorber [0062] 21 Fifth absorber [0063] 22 Third damped crankshaft system [0064] 23 Third crankshaft system frequency response [0065] 24 Maximum [0066] 25 Third vibration damper [0067] 26 Outer element [0068] 27 Connecting element [0069] 28 Spoke [0070] 29 First spoke spring [0071] 30 Second spoke spring [0072] 31 Third spoke spring [0073] 32 Axis of rotation [0074] 33 Rolling body [0075] A Vibration amplitude [0076] f Rotation frequency