JPH0152960B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration absorbing device for sound absorbing equipment and precision equipment.

Conventionally, methods using mechanical loss are well known for absorbing vibrations.

When using mechanical loss, it is mainly composed of a vibrating part, a loss generating part, and a support part, and the vibration energy of the vibrating part is converted into thermal energy in the loss generating part, and the rest is transmitted to the support part. When converting into thermal energy, it is difficult to find a material whose vibration damping characteristics are uniform from low to high frequencies in the mechanical loss generating part, so the vibration energy is also transmitted to the support part, and the vibration of the support part is reduced by the area of the equipment, etc. Even if the vibration energy of the supporting part is small because the vibration is propagated to a wide casing part, the vibration radiated from the wide area can be heard as noise.
Furthermore, in the case of mechanically absorbing vibrations, it is difficult to maintain loss by applying tension beyond a certain level using a viscoelastic material, as this causes deformation of the viscoelastic material. Furthermore, when a viscoelastic material is used, it has the disadvantage that its loss characteristics change when it is compressed and expanded by vibration energy.

The present invention was made in order to solve the drawbacks of the above mechanical loss adding method, and includes a vibrating part, a conductor connected to the vibrating part, and a magnetic member for forming a magnetic field parallel to the conductor. The vibration of the vibrating part is transmitted to the conductor and the conductor vibrates, and as the conductor vibrates in a parallel magnetic field, the conductor cuts off the magnetic flux and eddy current flows through the conductor, and the eddy current cancels the vibration of the conductor. The present invention provides a device that absorbs vibrations by being damped by a magnetic field in a direction.

This will be explained in detail below using the drawings.

FIG. 1 is a cross-sectional view of the vibration absorbing device of the present invention provided on a speaker edge, FIG. 2 is an enlarged view thereof, and FIG. 3 is another embodiment.

A magnetic circuit of a speaker is constructed by a magnet 4, a center pole 5 and a top plate 6, a voice coil 3 is provided in an air gap 7, and a voice coil bobbin 2 is fixed to a diaphragm 1. Net-like top cover 9
The structure is such that the diaphragm 1 is protected by the diaphragm 1 and the speaker is attached to the frame 10.

Input terminals 11a and 11b provided on the frame 10
The speaker is driven by this. An edge 14 is inserted into the edge portion of the diaphragm 1, and magnets 12a, 12 are attached above and below.
b. The magnets 12a and 12b vibrately support the edge 14 by a spacer 13 made of an elastic material such as paper or rubber. A conductive material is formed on the edge 14, and magnets 12a and 12b are arranged with their magnetic poles facing each other so that a magnetic field parallel to the edge 14 is generated. When an input is applied from the input terminals 11a and 11b, a current flows through the voice coil 3, driving the bobbin 2, and the bobbin 2 vibrates together with the diaphragm 1. The vibration energy of the diaphragm 1 is absorbed mechanically by the bending vibration of the edges, and the edge of a conductive material placed parallel to the magnetic field cuts the magnetic flux due to vibration and generates an overcurrent, and the energy is absorbed electromagnetically. Ru. On the other hand, expansion and contraction vibration inside the diaphragm, such as resonance vibration due to the shape of the diaphragm, also produces an electromagnetic energy absorption effect due to a change in the volume of the conductor.

A conductive washer 15 is placed on the edge as shown in Figure 3.
It is also possible to create a parallel magnetic field by narrowing the edge 14 by a and 15b and using a magnet having a different vibration mode from the conductive washers 15a and 15b, such as a fluid or a viscoelastic magnet such as a rubber magnet. By varying the width and strength of the parallel magnetic field, it is also possible to adjust the characteristics of absorbing vibration energy. As shown in FIG. 4, a magnetic field is provided at the center of the conductive diaphragm 1 by magnets 22a and 22b which are magnetized to generate a magnetic field approximately parallel to the diaphragm, and the energy of the diaphragm is concentrated. It is placed in the center and has the effect of electromagnetically absorbing vibrations, damping the unique resonance sound of the diaphragm, and damping the unique sound quality due to its shape.

FIG. 5 shows magnets 12a and 12b that generate a magnetic field parallel to the end of a diaphragm 16 of a microphone.
7 and is held by a damper material 18 or the like, and tension is applied to the diaphragm 16 from the surroundings. magnet 1
By electromagnetically absorbing vibration with 2, 12' and the conductive part, the reflection of the diaphragm at the edge part is controlled by the width and shape of the conductor or the width and strength of the magnetic field, and the vibration mode unique to the diaphragm is controlled. It becomes possible to control the Magnets 12a, 12b and damper material 18
Alternatively, a magnetic fluid or a rubber-like magnetic material may be used to create a structure in which the conductive portion is formed into a sandwich-like structure.

FIG. 6 shows an example of a structure in which the tension wire 23 of the vibration system support device of a pick-up cartridge is used as a conductive part to perform electromagnetic control.The stylus 24 is attached to the tip of a cantilever 25, and this part is used for disc records. Trace the groove.

A magnet or pick-up coil 26 is installed at one end of the cantilever 25, and a damper 27 supports the magnet or pick-up coil 26 so that it can vibrate freely, and a tension wire 23 is provided between the cantilever 25 and the sleeper 28.

The tension wire 23 is connected to magnets 29a and 29b.
A parallel magnetic field is provided, and since the tension wire 23 is conductive, it is braked by the magnetic field. A magnetic fluid or a rubber magnet may be provided around the tension wire 23, and the tension wire 23 may be placed in a parallel magnetic field. Since the natural vibration mode of the entire vibration system including the tension wire 23 is electromagnetically controlled and the vibration energy of the vibration system is absorbed together with the tamper, the vibration energy transmitted to the sleeper 28 can be reduced. Further, a rod-shaped tension wire or a flat plate-shaped portion that can reduce vibration reflection at the end portion may be provided in the magnetic field to increase the conductive area parallel to the magnetic field.

As mentioned above, by providing a conductor parallel to the magnetic field in a magnetic field connected to the vibrating part, unnecessary vibrations of the vibrating part and the conductor can be electromagnetically controlled, and by providing a conductor parallel to the magnetic field, the magnetic flux can be transferred to the conductor. Since the conductor can be made thinner, the lightness of the conductor makes it easier to transmit vibrations from the vibrating part, which has a great effect.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention;
FIG. 2 is an enlarged sectional view of the main part of FIG. 1, FIG. 3 is a sectional view showing the main part of another embodiment of the invention, and FIG. 4 is a sectional view of another embodiment of the invention. 5 and 5 are cross-sectional views of another embodiment of the present invention, and FIG. 6 is a cross-sectional view of another embodiment of the present invention. 1 is the diaphragm, 2 is the bobbin, 3 is the voice coil,
4 is a magnet, 5 is a center pole, 6 is a top plate, 7 is an air gap, 9 is a top cover, 10 is a frame, 11 is an input terminal, 12 is a magnet, 13 is a spacer, 14 is an edge, 15 is a washer, 16 is a diaphragm , 17 is a conductive part, 18 is a damper material, 22 is a magnet, 23 is a tension wire, 2
4 is a stylus, 25 is a cantilever, 26 is a pick-up coil, 27 is a damper, 28 is a sleeper, and 29 is a magnet.

Claims (1)

[Claims] 1. A vibrating part, a conductor connected to the vibrating part, and a magnetic member forming a magnetic field parallel to the plane or central axis of the conductor are provided, and the vibration of the vibrating part is transmitted to the conductor, causing the conductor to vibrate. A vibration absorbing device characterized in that an eddy current is generated in the conductor, which is damped in a magnetic field and absorbs vibration energy.