RU208879U1 - Shielded acoustic device - Google Patents

Abstract

The utility model relates to acoustic technology, namely to a device designed to reproduce sound, and which can be used in tests during which the objects to be tested must be exposed to an acoustic signal (sound pressure), and measuring devices should not be affected side electromagnetic radiation of the sound source. The acoustic device contains an electrodynamic loudspeaker installed in the housing, while the loudspeaker is divided into two parts - electromagnetic and acoustic. Moreover, the electromagnetic part, together with the signal amplifier, power supply and other electronic modules, is placed in a shielding container, which is fixed in the housing, and the electromagnetic part of the loudspeaker is connected to the acoustic part of the loudspeaker, which is fixed in the device housing outside the shielding container, by a pusher, with the help of which the mechanical vibrations are transmitted from the electromagnetic part to the acoustic part. EFFECT: increased efficiency of shielding from spurious electromagnetic radiation (SEMI) of an acoustic device while reducing the weight and size characteristics of the screen. 4 w.p. f-ly, 5 ill.

Description

The utility model relates to acoustic technology, namely to a device designed to reproduce sound (shielded speaker), and which can be used in tests during which the objects to be tested must be exposed to an acoustic signal (sound pressure), and the measuring devices must not must be exposed to electromagnetic radiation from the acoustic device.

It is widely known that shielding is used to protect against electromagnetic radiation (RU 144841 U1, publ. 09/10/2014), a container with EMI shielding is known, which consists of a housing made of electrically conductive material having a bottom, side, front and rear walls and a lid connected hinges and cylindrical shock absorbers with the possibility of rotation for opening and closing; means of shielding in the closed state, placed along the perimeter of the connector of the cover and the housing; ventilation panels in the walls of the case; a locking device that provides a power contact connection of the shielding means when the lid is closed; universal interface board of the input/output controller installed in the case; at least one ventilation unit is installed on one of the walls, consisting of a ventilation panel shielding electromagnetic radiation and a fan, and on the opposite wall there is a ventilation panel, while the following are installed on the walls inside the case: a power supply unit, a power splitter, a shielded surge protector , network hub, media converter and shielded input-output connectors for fiber-optic communication lines of the media converter (“twisted pair-FOCL”); the cover has a viewing window with an optically transparent filter that shields EMP; the body and lid have a locking device that allows sealing the container in the closed state; one of the walls of the housing provides for the installation of shielded input-output connectors for fiber-optic communication lines and a media converter. The disadvantages of this solution are the complexity of this solution and the large weight and size characteristics of this container, as well as the fact that in order to ensure the free exit of air that creates sound pressure from the shielding container, it is necessary to make holes (windows) in it, which significantly reduce the shielding efficiency.

From a source found on the Internet: http://infobez.org/activities/catalog1/szi_tk2/zawita_informacii_v_special_no_formiruemyh_kanalah2/kolonka_akusticheskaya_ekranirovannaya_uek/ an acoustic device is known that is designed to create acoustic pressure in the frequency range from 125 Hz to 10 kHz when conducting special studies of electronic equipment in order to reveal the effect of electroacoustic transformations. The disadvantages of this solution are the large weight and size characteristics of the screen for the acoustic device, as well as the fact that in order to ensure the free exit of air that creates sound pressure from the shielding container, it is necessary to make holes (windows) in it, which significantly reduce the shielding efficiency.

The objective of the utility model is to overcome the shortcomings of the prototype by creating a shielded acoustic device for testing.

The technical result of the utility model is to increase the efficiency of shielding from spurious electromagnetic radiation (SEMI) of an acoustic device while reducing the weight and size characteristics of the screen.

The technical result is achieved due to the following features of the shielded acoustic device. The shielded acoustic device contains an electrodynamic loudspeaker installed in the housing, while the loudspeaker is structurally divided into two parts - electromagnetic and acoustic, and the electromagnetic part is placed in a shielding container, which is fixed inside the device housing, and the acoustic part is placed outside the shielding container and is also fixed in the housing device, wherein the electromagnetic part of the loudspeaker is connected to the acoustic part of the loudspeaker by a pusher, through which mechanical vibrations from the electromagnetic part are transmitted to the acoustic part. Inside the shielding container, in addition to the electromagnetic part of the loudspeaker, there is a signal amplifier, a power supply unit and other electronic modules.

The acoustic part includes a diffuser placed on a suspension in the diffuser basket, a centering washer between the basket and the diffuser, and a dust cap.

The electromagnetic part includes a copper wire coil placed in the annular gap of the permanent magnet and core, coil centering washers and a frame.

Under the influence of an alternating electric current flowing through the coil, mechanical (vibration) vibrations of the coil relative to the magnet occur in the electromagnetic part. To create an acoustic signal that creates sound pressure in the air space surrounding the device, in one of the embodiments, using a pusher, through a small hole in the shielding container, mechanical vibrations from the coil installed in the electromagnetic part inside the shielding container are transmitted to the diffuser installed in the acoustic parts. The push rod can connect the coil and diffuser through hinges, each of which is connected to the coil and diffuser to transmit vibrations at different angles.

The shielding container (casing) can be made of a ferromagnetic material, such as steel or permalloy with a high relative magnetic permeability.

The utility model is illustrated by drawings

figure 1 is a schematic view of the acoustic device;

Fig.2 - acoustic part of the loudspeaker;

Fig.3 - electromagnetic part of the loudspeaker;

Fig.4 - acoustic device - general view without shielding container and housing;

Fig.5 - an acoustic device with an electromagnetic part, an amplifier and a power supply placed in a shielding container (casing or shielding plates forming a closed shielding housing) - general view.

1. The body of the acoustic device.

2. The electromagnetic part of the loudspeaker.

3. Acoustic part of the loudspeaker.

4. Pusher (rod, lever).

5. Shielding container in section (casing or plates fastened together forming a closed shielded volume)

6. Amplifier, power supply, other electronic modules (placement option inside the container).

Typically, acoustic test devices (sound pressure) are made using electrodynamic loudspeakers (speakers), which have many advantages. However, during operation, large electric currents flow through the speakers, which create high-level electromagnetic spurious emissions (SEMI). Due to the occurrence of TEMP created by an acoustic device, interference may appear on the measuring lines, which can lead to measurement errors.

The proposed design will significantly reduce the effect of TEMP on the test results generated by the acoustic device.

The proposed solution is based on the task of constructively dividing the electrodynamic loudspeaker into two parts:

the electromagnetic part, the purpose of which is the conversion of electric current oscillations into mechanical (vibration) oscillations of the coil;

acoustic part, the purpose of which is the conversion of mechanical (vibration) vibrations of the coil into an acoustic signal (sound pressure fluctuations; pusher transmitting coil vibrations).

The transmission of mechanical (vibration) vibrations from the electromagnetic part to the acoustic part will be carried out using a pusher, which can have a different design.

During the operation of the device, the electromagnetic part is a source of PEMI that interferes with research, and the acoustic part is a source of sound, for the propagation of which there should be no obstacles. By placing the electrical part in a shielding container, and the acoustic part outside it, it is possible to significantly reduce the level of PEMI without creating obstacles to the free propagation of an acoustic signal.

In conventional loudspeakers, the electromagnetic part is rigidly fixed to the acoustic part, so that the loudspeaker is integral and cannot be separated. As a result, by placing an ordinary loudspeaker in a closed shielding container, it is possible to reduce the level of PEMI, but create an obstacle to sound. If, however, holes are made in the shielding container for the sound to exit (window), the shielding efficiency will sharply decrease due to the violation of the integrity of the screen.

Thus, it is proposed to divide the electrodynamic loudspeaker into two structurally independent parts - electromagnetic and acoustic. At the same time, the acoustic part of the loudspeaker includes: a diffuser, a diffuser basket, a dust cap or a component replacing it, a centering washer, and the diffuser design contains elements that allow it to be connected to the pusher directly or through a hinge. The electromagnetic part of the loudspeaker includes a coil, a magnet, one or more centering washers, a frame, and the coil design contains elements that allow it to be connected to the pusher directly or through a hinge.

Also, the electromagnetic part of the loudspeaker is installed in a shielding container (casing) made of ferromagnetic materials (permalloy or steel). The shielding container with the electromagnetic part of the loudspeaker, amplifier, power supply and other electronic modules is fixed in the housing and, by means of a pusher connected to the coil directly or through a swivel joint, through a hole in the container is connected to the acoustic part (diffuser) directly or also through a swivel joint. In this case, the acoustic part is outside the shielding casing and is also fixed in the housing.

Mechanical vibrations from the electromagnetic to the acoustic part will be transmitted using an additional element - a pusher, which can have a different design (rod, lever, etc.), including the use of hinges to transmit vibrations at different angles.

The main advantage of the proposed design is that the acoustic part can be removed from the shielded volume, which has the largest geometric dimensions and also requires holes (windows) for air. Only the electromagnetic part needs to be shielded. At the same time, it is not necessary to make a large number of holes or a window in the shielding container to ensure free air movement that violates the integrity of the shield. In addition, the volume and weight of the screen is reduced.

Thus, the proposed design can significantly improve the shielding of acoustic systems while reducing the mass and volume of the screen.

Claims (5)

1. A shielded acoustic device containing an electrodynamic loudspeaker installed in a housing, while the loudspeaker is divided into two parts - electromagnetic and acoustic, and the electromagnetic part is placed in a shielding container made of ferromagnetic material, which is fixed in the housing, and the acoustic part is fixed in the device housing outside shielding container, wherein the electromagnetic part of the loudspeaker is connected to the acoustic part of the loudspeaker by a pusher, through which mechanical vibrations are transmitted from the electromagnetic part to the acoustic part. 2. Shielded acoustic device according to claim 1, characterized in that the acoustic part includes a diffuser placed on a suspension in the diffuser basket, a centering washer between the basket and the diffuser, and a dust cap. 3. Shielded acoustic device according to paragraphs. 1, 2, characterized in that the electromagnetic part includes a coil placed in the annular gap of the permanent magnet and the core, coil centering washers and a frame. 4. Shielded acoustic device according to claim 3, characterized in that, with the help of a pusher, mechanical vibrations from the coil in the electromagnetic part are transmitted to the diffuser in the acoustic part. 5. Shielded acoustic device according to claim 4, characterized in that the pusher can connect the coil and diffuser through hinges, each of which is connected to the coil and diffuser to transmit vibrations at different angles.

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