DE1071364B - - Google Patents

Description

GERMAN

kl. 42 g 1/10

INTERNAT. KL. G 01 h

PATENT OFFICE

S 44468 VIIId / 42 _g

REGISTRATION DATE: June 24, 1955

NOTICE THE REGISTRATION AND ISSUE OF THE

AU S LE GE S CH RI FT: December 17th, 1959

To with vibrating bodies, z. B. the containers of electrical induction apparatus, preferably at Transformers caused by the magnetostriction of the iron core, for the environment very much It is known that various measures have already been taken to reduce disturbing noise. So tried mah z. B. the sound propagation in the direction of the noise endangered locations by the vibrating Boundaries, walls, special casings, etc. around the body to distract, or the noises were tried to be distracted to be combated by means of so-called Helmholtz resonators or even by counter sound. Also sound-absorbing casings, in particular double walls on the vibrating body as well as on the Damping means placed on vibrating bodies are known for reducing noise. Also was already tried to constructively train the body, which tends to vibrate, so that it is less to the Swing came. All of these aforementioned measures are expensive because they involve considerable effort Require material or expensive constructions. Moreover, with them is only a partial and multiple unsatisfactory noise control achievable.

Also known electrical oscillation systems, in which the movement of the sound generating organ a circuit is closed, which affects a magnet before the vibrating part is arranged and whose sound vibrations cancels, are intended for Purpose on the one hand too cumbersome and expensive and on the other hand they are because of their low robustness and lack of weather resistance not useful.

Here, the invention, which works with oscillation elements oscillating in antiphase, creates a simpler one and cheaper way to remedy this by reducing the interference frequencies that occur on the vibrating body by mechanical vibration systems, the natural frequencies of which are approximately equal to those of the vibrating Frequencies occurring in the body are reduced, preferably by the formation of interference in the airborne sound are using vibration systems, which preferably consist of plates or strips, by means of an exciter pin attacking them in the center at a distance from the vibrating one Body are attached.

According to a further development of the invention, the vibration systems can be in the form of plates or strips have and can above all through substances known per se of higher internal friction, e.g. B. rubber and the like, still be dampened.

According to another development of the invention, only one plate or strip can be attached to the exciter pin, in particular at its free end, or several plates or devices for reducing structure-borne noise in vibrating bodies can just as well be attached

Applicant:

Siemens-Schuckertwerke Corporation, Berlin and Erlangen, Erlangen, Werner-von-Siemens-Str. 50

Dipl.-Ing. Erich Reiplinger, Nuremberg, has been named as the inventor

Strips are arranged on top of one another on it. The plates or strips can be in their Shape and size be chosen so that the resonance frequency is approximately equal to the frequency of the exciting vibrating body is.

With reference to the drawing, which in Figs. 1 to 4 different embodiments according to the invention shows, the invention will be explained in more detail.

In FIG. 1, 1 indicates a container wall on which mechanical vibration systems 2 are placed. These consist, as shown in FIG. 2, each of a preferably thin, with one of the known damping materials 4, z. As rubber occupied ferrous metal strip 3. At the center of the strip 3 is engaged attached to the container wall 1, for example welded, screwed, soldered pin 5 (exciter pin) and thus creates a firm connection between the container wall 1 and strip 3. The sheet metal strip 3 is selected in its size and shape, and adjusted by the damping lining 4 placed on it, that it oscillates in resonance with the excitation frequency, namely the container wall 1 . This results in an energy withdrawal as in the damping parts already proposed for the same purpose, which were made of rubber. Because a certain amount of whale motion takes place in the oscillation systems 2 according to the invention, there is an immediate destruction of energy. With the vibration systems according to the invention, even relatively small exciter amplitudes can be effectively combated, since one has it easily in hand by appropriate dimensioning of the damping lining 4 , a sufficiently large one

909 689/284

Claims (4)

Vibrating amplifiers as they are necessary for each energy dissipation to be adjusted approximately in resonance with the vibrating wall 1. When using sheet metal strips as damping members, several such strips can be arranged one above the other on the same exciter pin 5, as indicated by dashed lines in FIG. 2 at 6 and 7. The advantage here is that these strips can then be selected in terms of their shape or size so that they can oscillate with a different natural frequency, that is to say deviating from the natural frequency of parts 3 to 4. The vibration systems can of course also be designed otherwise, for. B. In particular, they can be made of round plates 10, as can be seen in FIG. 3; These round plates are also provided with damping linings and are connected with their center to the exciter pin 11 fastened on the vibrating body. In vibration systems constructed in this way, in which several disks of different sizes can also sit one on top of the other on the exciter pin 11, it is possible to generate the same frequency or the same frequency mixture by generating interference with a phase shift of approximately 180 ° from the vibration system as it is radiated by the exciting vibrating body, because in vibration systems consisting of round plates, the undamped plate vibrations at a natural frequency that is below the excitation frequency are always shifted by about 180 ° compared to the exciting vibration of the vibrating body. This can be seen from the diagram according to FIG. 4, where 12 represents the> curve for the airborne sound oscillation of the vibrating body and curve 13 the airborne sound oscillation, offset by 180 °, of the oscillation systems attached to the vibrating body. Since the distance between the plates of the vibration system from the vibrating body, e.g. B. a container wall, will always be small compared to the wavelength of the occurring frequency, the same starting point can be assumed for both sound sources, namely container wall and vibration system, so that the conditions for sound suppression are indeed given. In general, you will get by if you equip two opposing side walls of square containers with vibration systems according to the invention and these are preferably evenly distributed on the walls. For the vibration systems, plates with a diameter of about 250 mm have proven to be particularly useful if they are arranged 30 to 40 mm in front of the vibrating container wall. By choosing the resonance frequency of the vibration systems just below the excitation frequency of the vibrating body, the greatest possible amplitude can be achieved for the energy dissipation through flexing, and in the vicinity of the resonance the largest radiating surface with 180 ° phase shift results on the plate. The damping of the oscillation systems according to FIG. 3 depends on the airborne sound amplitude that is most favorable for the formation of interference. If the vibration systems are evenly distributed in front of the vibrating body, this results in, for. B. a boiler wall, as it were a second wall, which is body and airborne sound-absorbing and which still has a certain sound absorption with appropriate selection of the damping means. Patent claims: 1. Device for reducing structure-borne noise in vibrating bodies, in particular in containers of electrical equipment, e.g. B. transformer boilers, with the help of in antiphase vibrating vibration elements, characterized in that the vibrating Body interference frequencies caused by mechanical vibration systems, their natural frequencies are approximately equal to the frequencies occurring on the vibrating body, preferably through Interference formation in airborne noise can be reduced by using vibration systems, which preferably consist of plates or strips that act on them centrally by means of a Exciter pin are attached to the vibrating body at a distance. 2. Device according to claim 1, characterized in that the vibration systems of the for example made of iron plates or strips with per se known material of higher internal friction, e.g. B. rubber, are more or less damped. 3. Device according to claim 1, characterized in that one or on an exciter pin several vibration elements of different natural frequencies are arranged one above the other. 4. Device according to claim 1 or 2, characterized in that the shape of the oscillation systems z. B. in plate or funnel shape is chosen so that interference formation in the airborne sound arises. Considered publications:
German Patent No. 313,656;
Swiss Patent No. 234 383. 1 sheet of drawings © 909 689/284 12.59