WO2008014744A2

WO2008014744A2 - Method for reducing vibrations in a disc-shaped rotary component which is rotatable about a rotational axis, and rotary component

Info

Publication number: WO2008014744A2
Application number: PCT/DE2007/001241
Authority: WO
Inventors: Boris Ryzhik
Original assignee: Luk Lamellen Und Kupplungsbau Beteiligungs Kg
Priority date: 2006-08-03
Filing date: 2007-07-12
Publication date: 2008-02-07
Also published as: CN101501363A; WO2008014744A3; DE112007001664A5; CN101501363B

Abstract

The invention relates to a method for reducing vibrations in a disc-shaped rotary component which is rotatable about a rotational axis, which rotary component is in sliding frictional contact, by means of a circular face which is coaxial with respect to the rotational axis, with a mating face of a mating component relative to which the rotary component rotates, in which method the rotary component is designed such that a cyclic symmetry which exists about the rotational axis of said rotary component is disrupted.

Description

A method for reducing vibrations on a rotating about a rotation axis disc-shaped rotary member and rotary member

The invention relates to a method for reducing vibrations on a disc-shaped rotary member rotating about an axis of rotation which is in frictional sliding contact with a counter-surface of a counterpart member with a circular surface coaxial with the rotary axis relative to which the rotary member rotates.

The invention further relates to a disc-shaped rotary member which is rotatable in an installed position about a rotation axis and with a coaxial to the rotation axis circular surface in sliding frictional contact with a counter surface of a counterpart member can be brought, relative to which the rotary member is rotatable.

Vibrations, especially vibrations audible in the audible frequency range as squeaking, are a common problem in the art when frictional contact exists between a mating surface and a rotating component rotating relative to the mating surface. A typical example of such audible vibrations is brake squeal, which occurs in track vehicles as well as motor vehicles.

The elimination of such vibrations has been used for many years with varying degrees of success.

The invention has for its object to provide a solution for the described vibration problem.

This object is achieved by a method for reducing vibrations on a disc-shaped rotary member rotating about a rotation axis and slidingly rubbing against a circular surface coaxial with the rotation axis with a counter surface of a counterpart member relative to which the rotary member rotates Method, the rotary member is formed such that an existing about its axis of rotation cyclic symmetry is disturbed.

Overall surface-formed, about a rotation axis rotatable rotary components having a coaxial circular surface which has an outer peripheral surface or an axially directed Surface may be in frictional contact with a mating surface of a mating member, represent membrane-like components that are excitable to various vibration modes. The sliding frictional contact can lead to a feedback between modes of the same shape but reversing tangential position or opposite position in the direction of rotation, such modes having the same natural frequency. The feedback between such modes with the same frequency leads to instability.

Extensive research has shown that the feedback binds paired modes of the rotary component together and therefore the cyclic symmetry of the rotary component plays a major role.

A disturbance of the cyclic symmetry separates the frequency of the feedback modes, which disturbs the instability conditions and reduces or largely suppresses the occurrence of vibrations.

Advantageously, the rotary member is longitudinally provided in the circumferential direction with asymmetrically arranged and / or unbalanced shaped disturbances whose number is m, where n / m is not an integer and n is the number of symmetry cycles of the rotary member.

An inventive disc-shaped rotary member, which is rotatable in an installed position about an axis of rotation and can be brought into sliding frictional contact with a counter surface of a counter component with a coaxial to the axis of rotation circular relative to which the rotary member is rotatable, is disturbed about its axis of rotation, cyclic symmetry is trained.

Advantageously, the rotary member is provided with circumferentially asymmetrically arranged and / or relatively unsymmetrical trained windows in a number m, where: n / m no integer and n = number of symmetry cycles of the rotary member.

The dimensions of the windows advantageously satisfy the following relationships: width of each window in the circumferential direction greater than 5 degrees; Radial length of each window greater than 10% of the radial length of the rotary member in the region of the window. For the arrangement of the windows advantageously the following relationships apply:

- radial unbalance -≡ * ≡ ^L > 0.2,

tangential imbalance ΔΦ _max -ΔΦ _min > 10 °, where i? ,, ζz? ₍ The radial and tangential position of the "center of gravity" of the window i (i = l, ..., m) are and

^ _nax = ∞ax {R. }, R _mia = mm {R.}, I = 1, ..., m;

^Δφ _« = K - il i = l, -, m - 1; ΔΦ _m

AΦ. _nax ^ maxJΔΦ,}, ΔΦ _rain = min {Δφ _min }, i = 1, ..., m.

The invention is applicable to substantially all types of excitable to natural oscillations, in particular to natural oscillations with the same shape but reversing tangential position or position in the circumferential direction components. Such components are mainly components that are made for example of a flat disc with optionally different thickness, for example, by warping, pressing or otherwise which deformation of the disc out of its surface. The disc can also remain flat, such as a brake disc.

Advantageously, the invention is applicable to a sealing membrane on a dual mass flywheel.

The invention is explained below with reference to schematic drawings, for example, and with further details.

In the figures represent:

Fig. 1 u. FIG. 2 shows a circular ring disk in two oscillation modes with the position reversed in the circumferential direction; FIG.

3 shows a sealing membrane, which is radially inwardly in rotationally fixed connection with a first disc part of a dual mass flywheel, and radially outside under axial bias in frictional contact with a second disc part; - A -

4, 6,

8 u. 10 three embodiments of sealing membranes with different

Window number,

Fig. 5, 7, 9 and 11 belonging to the figures 4, 6, 8 and 10 natural vibration characteristics and

Fig. 12 u. 13 two different arrangements of four windows in a sealing membrane.

Fig. 1 shows a slightly perspective view of a circular disk, which is preferably formed flat and has a small thickness relative to its diameter. The annular disk 20, which may be aligned flat or curved, has an inner diameter R ₁ and an outer diameter R ₂ . The annular disc is clamped and fixed at its inner diameter and is at its outer diameter under radial bias on the inner surface of a coaxial with the annular disc 20 arranged circular cylinder which rotates. Alternatively, the arrangement could also be such that the circular cylinder is stationary and the annular disc rotates.

Due to the radial bias there is a standing in the plane of the circular disc, standing perpendicular to its outer diameter normal force. As a result of the sliding contact there is a tangential force acting in the tangential direction of the annular disc.

The circular ring disk is a component that can be excited to oscillate, with the eigenmodes of the oscillation of the _{annular disk having the} form: W _A (r, φ) = R _{nln 2} (r) meaning ₂ φ, w _B (r, φ) = R _{nhl 2} (r) cosn ₂ φ, where r, p are coordinates in the cylindrical coordinate system and ni = 0,1, 2 ...; n ₂ = 0,1, 2 ...; whole numbers are.

Such modes in the case n ₂ ≠ 0 have along the circumference n ₂ bulges and depressions or vibration surfaces, between each of which a node is located. An instability of the oscillation occurs in particular if for each mode a "pair" (sτ _α <- »m _b ) with the same frequency is present, with the bulges and depressions of one mode exactly in the position where the other one Mode has vibration node. Fig. 1 shows darkly indicated a vibrobelly at the top and bottom in the figure, the nodal line extending horizontally between the bellies. Fig. 2 illustrates the paired mode, in which the darkly indicated antinodes 22 lie in the horizontal and the node line, not shown, is perpendicular.

When the annular disk oscillates in the modes according to FIGS. 1 and 2, a change in the normal force takes place under frictional contact along the circumference of the annular disk, which maximum in the area of the antinodes and is minimal in the area of the vibration nodes. The change in the normal force leads to changes in the tangential force. The change in tangential force affects the paired modes, which provides feedback between the paired modes. Without damping, such modes are unstable.

The axial deformation of the disc leads to periodic changes in the normal force. Due to the friction, this periodic change of the normal force leads to a periodic change of the tangential force. The tangential changes cause no change in the axial force, whereby the system's stiffness matrix is unbalanced when rubbed.

The natural frequencies of the mechanical system can be interpreted as complex numbers, with their imaginary part indicating the oscillation frequency and the real part describing the stability. If the real parts of all eigenfrequencies are negative or equal to zero, the system is stable. The formation of natural frequencies with positive real parts, on the other hand, means instability.

Without damping, the systems with symmetrical stiffness matrix are stable. They only have natural frequencies with real parts with the value zero. If the stiffness matrix is asymmetrical, the real parts of some eigenfrequencies can become non-zero.

The analysis of complex eigenfrequencies considering the asymmetry of the stiffness matrix allows to study the stability in systems with friction. ANSYS 10.0 with QR Damped modal analysis is a program that makes such analyzes feasible. The analysis of complex natural frequencies allows not only qualitative, but also quantitative statements. The size of the real parts λ of the complex eigenfrequencies shows how the corresponding Eigenmodeamplitude changes. Zero real part (/ 1 = 0) means constant oscillation amplitude; if λ is not equal to zero, there is the expression A (t) = A ₀ E ^λt , which is the Indicates the amplitude of a vibration as a function of time, λ> 0 means an increasing oscillation, ie instability, and λ <0 a reduction of the oscillations.

The natural frequencies, especially their real parts, depend not only on the asymmetry of the stiffness matrix, but also on the attenuation. In contact friction systems, damping is an uncertain parameter because it varies with vibration frequency and amplitude, coefficient of friction, contact force, and many other factors. Therefore, the precise introduction of damping in Q-R Damped modal analysis is not possible and the modal analysis is done without attenuation inventory. The magnitude of the positive sign real parts in systems without attenuation is used as a criterion of instability of the different eigenmodes.

In the calculations, a coefficient of friction of 0.5 is assumed, because squeaks occur in tests on a lathe, when the coefficient of friction increases in contact by local material removal to μ = 0.5 - 0.6. The eigenvalues are evaluated in the frequency range up to 10000 Hz (typically the density diaphragm squeak frequency is between 2000 and 8000 Hz).

In the following, the above considerations are explained in their application to a sealing membrane, as used in a dual-mass flywheel, as described for example in DE 100 02 259 A1. Such a sealing membrane is a preferably metallic annular disc which is rigidly connected at its inner peripheral region with a first disc part of the dual mass flywheel, for example by riveting and which is axially arched from its riveted radially inner region and in its radially outer region under axial prestress in sliding friction contact with a second disc part of the dual mass flywheel, which is mounted coaxially with the first disc part and is rotatable relative to the first disc part to a limited extent.

Fig. 3 shows in supervision the conditions:

With 30 the annular sealing member forming the sealing member is denoted, which is connected at its circular radially inner portion 32 via dark registered connecting portions, such as rivets, with a disc portion 32 of a dual-mass flywheel, not shown, and at its radially outer portion 34 in slidable Reibberührung with the another disc part of the dual mass flywheel is. The friction contact is preferably preloaded axially, but may also be biased radially. In the poem Membrane windows are formed 36 whose task is explained in more detail below. The windows 36 have a radial extent ΔRi, where i is assigned to the respective window, and an extension in the circumferential direction over an angular range Δφi. The radial width of the annular disc 20 is H.

4 shows the arrangement of FIG. 3 with a windowless sealing membrane 30 and a dual-mass flywheel which is rotatable about an axis of rotation X or, respectively, a sealing membrane 30 which is rotatable relative to one of the disk parts about the axis of rotation X.

Fig. 5 shows characteristics of the vibration behavior of the sealing membrane 30 of Fig. 4. The abscissa indicates the frequencies of the natural vibrations in Hz. The ordinate indicates the above-explained values of λ in sec ^-1 (only for eigenfrequencies with λ> 0). As can be seen, there are numerous unstable natural frequencies or oscillation modes which fulfill the conditions for an energy exchange explained above and thus give rise to a form audible squeaks.

Fig. 6 shows an arrangement in which the sealing membrane 30 is provided with a window 36. After optimization of the window with regard to arrangement and dimensions, only nine eigenfrequencies with a positive real part result in the range between 0 and 10000 Hz, the maximum value of which is 44.4 sec ^-1 (FIG. 7).

When provided as shown in Fig. 8, two windows, resulting after their optimization with regard to position and size in accordance with Fig. 9, only two eigenvalues with a positive real part and a maximum value of 26.4 sec ^'1.

In the case of three windows in the arrangement and size of FIG. 10, according to FIG. 11, three natural frequencies with a positive real part result, the maximum value of which being only 5.6 seconds ^"1 .

In four windows (Figures 12 and 13), the sealing membrane in the range between 0 and 10000 Hz can be made completely stable, ie without eigenvalues with a positive real part. In this case, two different possible window arrangements are shown in Figures 12 and 13. The number of windows, their dimensions and their arrangement is as follows: The object of the arrangement of windows is a disturbance of the axial cyclic symmetry, so that the frequencies of feedback modes are different. There are various possibilities for this, for example a change in the bearing, a change in the component surface, a change in the component thickness, a change in the basis weight, etc. The provision of windows or sections to disturb the symmetry has proven to be effective.

1st number of windows m:

For a cyclic symmetric component with a number of cycles = n, the ratio n / m should not be an integer.

The minimum number of windows for axially symmetrical components (n = 1) is m = 2. For the illustrated sealing membrane with cyclically symmetrical mounting, n = 6 (result of the investigation on the example studied). The minimum number of windows is therefore m = 4, because at m = 1, 2 or 3 n / m = 6, 3 or 2.

2. Dimensions of the window:

The tangential width (angular range) of each window should be more than 5 ° (Δφ> 5 °).

The radial length ΔR of each window should be more than 10% of the radial dimension H of the sealing membrane.

3. Unsymmetrical arrangement:

Assume that R, and φi are the radial and tangential positions of the center of gravity of the window i and

ΔΦ,

l, ..., m -l; ΔΦ _B = | fl -flJ; Δφ _max = max {Δφ.}, Δφ _min = min {Δφ _min }, i = 1,..., M, then the following conditions should be fulfilled: - Radial asymmetry ^{Rram R∞ia} > 0.2,

- tangential asymmetry ΔΦ _max -ΔΦ _min > 10 °.

The windows are thus formed asymmetrically both in their position to each other and in their shape.

On the one hand, the optimum dimensions of the windows are not too small, because the influence on the instability of the vibration behavior to be eliminated then becomes too low and, on the other hand, not too great because of the strength and rigidity of the membrane. The influence of the windows on the instability of the vibration behavior should be checked by calculations.

Once the number of windows has been determined, their radial and tangential positions and their extent are optimized to minimize the number of eigenvalues with positive real parts and the maximum value of the real parts.

The testing of the effectiveness of the measures is carried out both by numerical examination with the Q-R Damped Modal Analysis in the ANSYS 10.0 program or similar procedure in other programs as well as on the test bench by directly examining the acoustic behavior.

The method according to the invention explained on the basis of its application to a sealing membrane with axial prestressing can be applied to all components rotating about one axis, which are in sliding frictional contact with another component, whereby the frictional force can act in the radial direction or axial direction of the rotating component , The term disk-shaped component includes pot-shaped or hat-shaped components which can be formed from a disk.

Targeted perturbation of paired eigenmodes has emerged as a developmental tool that is more effective than previous methods that attempted to reduce squeaking noise to stick-slip phenomena. LIST OF REFERENCE NUMBERS

Annular disk

antinode

sealing membrane

Area

window

Claims

claims

A method of reducing vibration on a disk-shaped rotary member rotating about an axis of rotation slidingly rubbing with a counter-surface of a counterpart member with a circular surface coaxial with the rotary axis relative to which the rotary member rotates, in which method the rotary member is formed is that a cyclic symmetry existing around its axis of rotation is disturbed.

2. The method of claim 1, wherein the rotary member is longitudinally provided in the circumferential direction with asymmetrically arranged and / or unbalanced shaped disturbances whose number is m, where n / m is not an integer and n is the number of symmetry cycles of the rotary member.

Third disc-shaped rotary member (30) which is rotatable in an installed position about an axis of rotation and with a coaxial to the rotational axis circular surface in sliding frictional contact with a mating surface of a counterpart member (34) is rotatable relative to which the rotary member is rotatable, which rotary member with is formed around its axis of rotation disturbed, cyclic symmetry.

4. Rotary component according to claim 3, which rotatable component with asymmetrically arranged in the circumferential direction and / or relatively unsymmetrical trained windows (36) is provided in a number m, where: n / m no integer and n = number of symmetry cycles of the rotary component.

5. Rotary component according to claim 4, wherein the dimensions of the window satisfy the following relationships:

Width of each window (36) in the circumferential direction greater than 5 degrees; radial length of each window (36) greater than 10% of the radial length of the rotary member in the region of the window.

6. Rotary component according to claim 4 or 5, wherein the following relationships apply to the arrangement of the windows: radial asymmetry ^{i max max i min} 0.2,

tangential imbalance ΔΦ _max -Δφ _min > 10 °, where i,,,,, are the radial and tangential position of the "center of gravity" of the window z ^" (j = 1, ..., m) and

K _∞ = max {i? _; .}, R _min = mmfal ⁱ = ^l >-> ^m >

^Δφ ,

i = 1, .., m - 1; ΔΦ, "-

- φ _m \,

Δφ _max = max {Δφ,}, Δφ _min = min {Δφ _min }, i = 1, ..., m.

7. Rotary component according to one of claims 3 to 6, which rotary member a sealing membrane (30) on a dual mass flywheel (32), wherein the sealing membrane at its radially inner or outer edge region rotatably with one of two coaxially arranged limited relatively rotatable disc parts of the dual mass flywheel is connected and with its radially outer or inner edge region in elastically biased contact with the other of the disc parts.