DE669911C - Sound transmitter in which a movable conductor oscillates in an air gap permeated by an alternating magnetic flux - Google Patents

Description

Sound transmitter in which a movable conductor in one of a magnetic Alternating flight. interspersed air gap oscillates so far when generating mechanical Vibrations with electromagnetic apparatus are generally considered to be vibrating System of armature used by an electromagnet. Due to the periodically changing Induction flight of the magnet is here a periodic movement of the armature, so z. B. the membrane of the acoustic radiator caused.

These known arrangements have serious disadvantages. Once causes the 1 \ Tagnetisierungsstroin, the generation of the attractive magnetic Field is required and depends on the size of the air gap that the field must bridge a considerable reactive power, the compensation of which a large capacity requires. Furthermore, at high frequencies, z. B. in the field of ultrasound, iin armature induces strong eddy currents, which are the attraction of the armature by the Counteracting magnets and ultimately canceling them.

It is also known to generate vibrations in the air gap a magnet to arrange a coil with an electrical resonance circuit connected to it. In this arrangement, however, result from the high resistance of the coil and cles connected, consisting of a capacitance and an inductance Circuit only extremely small currents and therefore only vibrations low amplitude. The vibrations of the coil are still required by the Feeds to your resonance circuit are further attenuated. Furthermore, the facility due to the relatively sharp resonance of the electrical oscillation circuit extremely frequency dependent.

The invention relates to a sound transmitter in which a movable, A conductor subjected to an elastic counterforce, which is a mechanical oscillation circuit heard, in an air gap permeated by a magnetic alternating flux oscillates to the field lines of the alternating flux. According to the invention, the movable Head designed as a short-circuit conductor and like a slide in such a way in the alternating flight interspersed air gap arranged immersed that he by the interaction of the elastic counterforce and the force generated by the flight along its length pinching edge induced eddy current is generated in the mechanical oscillation system moving vibrations is displaced. It can thereby be achieved that the sound transmitter extraordinarily efficient and also within a relatively large one hreqtienzl), "reiclies is also largely independent of frequency. hu a sound transmitter according to the invention is described below with reference to the 7eichnutigen.

In the gap i of an electromagnet (Fig. I) there is a slider-like Plate 2 made of electrically conductive material. The conductor surface is perpendicular to Direction of the field that penetrates the air gap.

Through a pure alternating flux, excited by the alternating current winding 3, an electric current is induced along the conductor edge of the plate 2, which compresses the flux on the parts of the air gap. Let s be the width of the air gap and H the magnetic field strength in the part - , v of the air gap, it follows for the current strength at the land of the plate i = H # , r. The force K, - which acts in the one-sided 1-magnetic field H in the air gap on the conductor element of length b through which the current i flows, is calculated ztt where,. (, = i,: 25 () # io-8 if H is measured in amps / cm and i in amps.

On the other hand, for the alternating flux, 0 = H # 1 # b, u0. This makes the force acting on the conductor periodically variable This force tries to push the conductor out of the air gap and can set the conductor and a mechanical system connected to it in motion. This movement becomes periodic when the electromagnetic force is generated by an alternating current and when the mechanical system is simultaneously under the influence of an opposing force, e.g. a spring force, which tries to push back the conductor in the air gap.

The basic frequency of the mechanical movement is the same (leg double the frequency of the electric current.

Is the alternating magnetic flux generated by the winding 3 a constant 1.71t11.1), e.g. B. by virtue of a further winding for direct current, superimposed, so. If the frequency is correct (put mechanical movement and (read alternating current with each other match; provided (measure the amplitude of the alternating field remains smaller than (read constant field.

The electrical-mechanical energy conversion can be finite run new device finitely favorable power factor, regardless of the Shape and properties of the membrane used in general of the mechanical vibration system.

By suitable choice of the rest position of the slide-type electrical Conductor between the poles of the magnet can be given with: Air gap and the phase shift for a given amplitude of the induction flux between current and voltage in the magnetizing coil, i.e. the power factor for the electrical system, can be adjusted to favorable operating conditions.

A valid choice of the power factor is synonymous with large 'self-induction and thus small compensation capacity.

Losses due to scattering at the edges of the gap can be avoided avoid that an extensive electrical conductor 4. (see. Fig.?) Umbrella-shaped is fixed in the way of the flow of dispute. Through the umbrella-shaped Alternating magnetic fields permeating conductors are induced in the conductor by eddy currents, whose magnetic field is opposite to the generating field. The leader can consequently not penetrated by a resulting field, the induction flux is forced to take his way outside of the ladder level, whichever is more appropriate Choice of conductor level is only possible between the poles of the magnet.

With the new device it will be possible to measure very high mechanical frequencies, in particular to generate ultra-acoustic vibrations. Because especially the eddy currents which occur disruptively with the electromagnetic vibration generators commonly used up to now, are used here to generate vibrations. The best way to do this is that inan an elastic system, e.g. B. a rod-shaped or cylindrical body, excited at a natural frequency.

A particularly favorable degree of efficiency (leg I? Inrichtung can thereby can be achieved (measure of the induced eddy current in its entire course in the air gap of a magnetic circuit is located, as (read in the following embodiments practically the case.

The slide-like electrical conductor that experiences the force is finitely advantageous cylindrical, in such a way (measure of one edge of the cylinder jacket immersed in a suitably selected air gap so that the (leg air gap penetrating Field lines intersect the conductor surface vertically.

As a magnet arrangement (Fig.3), which is' for the fanning of this oscillating mechanism A collection of simple laminated horseshoe magnets is particularly suitable 5 are used, which are arranged around (leg electrical conductor 6 so <1a13 (leg Head lies between the poles. A ring coil arranged coaxially with the conductor G. j excites the horseshoe race.

Three-legged magnets (Tig. 4) can also be used with two air gaps, which are put together again in such a way that a as large as possible of the cylinder edge is penetrated by the magnetic fields.

The opposite elicle of the cylinder jacket can be replaced by an at g mounted membrane 8 be closed by the movement of the cylinder jacket is excited to vibrate. According to another execution forums (Feg. 5) can the cylinder, which is open on one side, is excited to longitudinal natural vibrations, whereby it is clamped in a movement node io, while the movement abdomen dips into the air gap at the open end. The other end of the cylinder 6 is closed by a rigid plate i i, which is carried along by the vibrations and energy to the sound medium, so z. B. air or water, gives off. The slide-like one The conductor can also be pushed back into the air gap by a special spring. Conductor mass, possibly further masses, and the spring then form an oscillatory one System that plays a big role in using the device as a vibrating motor. Examples of such oscillating structures with the oscillating mass. more separated Elasticity are given in FIGS. 6 and 7. In Fig. 6, i-q is the slide type Conductor immersed in (read magnetic field; 13 is the elastic counterforce that represented by a coil spring; 14 is the fixed counter-bearing against which the coil spring is pressed. Another special version (Fig.7) for Such a system of vibrations is obtained if we use the mechanical system 15, at (learn the electromagnetic force attacks, uni one. To the direction of this Force vertical axis 1 (i rotatably arrange and the elastic counterforce 17, the also acts on the lever created in this way, counteracting the electromagnetic force let it work.

The diverse training opportunities for the vibration system allow, in addition to using the device as a sound transmitter, using it as a Oscillating motor that is suitable for driving devices where the rapid Rotation of a mechanical system is necessary or advantageous, such as B. with cutting and stalking tools, with hair clippers and shaving machines, fier massage devices, dental instruments or pumps that can be used directly from the AC mains are fed. Finally, it should be mentioned the possibility fast mechanical fluctuations zti use for periodic interruption of rays of light and electrical currents. 1) ic advantages of the new facility to generate mechanical vibrations are based on the possibility of a conversion from electrical energy into mechanical vibration energy with a favorable power factor to achieve. In particular, it is emphasized that the new facility is a possibility supplies for the generation of ultra-acoustic vibrations.

Claims (7)

PATE NTANSPRÜCK111 ?: i. Sound transmitter, in which a movable conductor, subject to an elastic counterforce and belonging to a mechanical oscillation system, vibrates in an air gap interspersed with magnetic alternating soot, transversely to the field lines of the alternating flux, characterized in that the conductor is designed as a short-circuit conductor and is like a slide is arranged immersed in the air gap penetrated by the alternating flow, (let it be caused to move vibrations through the interaction of the elastic counterforce and the force generated by the eddy current induced along its edge that constricts the alternating flow. 2. Sound transmitter according to claim i, characterized in that that the flux constricting slide-like conductor made of a material of high electrical Conductivity exists, e.g. B. silver or 13 silver bronze. 3. Sound transmitter after Claims 1 and 2, characterized in that the alternating flow is a direct current flow is superimposed so that if the Anipiitucle of the alternating flux remains smaller than the constant flux, the generated mechanical 1, frequency equal to the 11 reque11z des Alternating flow is. 4. Sound transmitter according to claim i to 3, in particular for very high frequencies and for ultrasound, characterized in that the slide-like, A conductor belonging to a mechanical system in a natural frequency of this system is excited. 5. Sound transmitter according to claim i to .4, characterized (#ichnet that the slider-like, vain mechanical system belonging to a ladder in well-known Way represents a pipe section (for example with a circular cross-section), who cintauclit in a circular gap of one or more r magnetic circles, so that the magnetic field lines cross the circular gap perpendicular to the axis of the 1 @@ 1 @ 1es push through. G. Sound transmitter according to Claims 1 to 5, characterized in that the slide-like conductor belonging to a mechanical oscillation system represents a cylinder of any cross-section, which is excited in the direction of the "cylinder axis to form longitudinal, standing waves by being held in a movement node while its free End, in which there is an abdomen of movement, dips into the gap of a magnetic circuit., 7. Sound transmitter according to claim i to G, characterized in that the slide-like, a mechanical system the common conductor is pushed back into the air gap by a helical spring, whose axis coincides with the axis of the mechanical system, the spring between a surface of the moving conductor perpendicular to its axis and a fixed counter bearing, while the slide vibration is transmitted to the mechanical oscillating system to be driven takes place in any way. B. Sound transmitter according to claims i to 7, characterized in that the slide-like, a mechanical Conductors belonging to the system are pushed back into the air gap by the tension a gas compressed by the movement of the conductor, e.g. B. from air. cg. Sound transmitter according to claim i to 8, characterized in that the slide-like conductor is a mechanical system that can be rotated around an axis perpendicular to the direction of force is where the magnetic force and the elastic force, both at your so attack the resulting lever, counteract each other. ok Sound transmitter according to claim i to 9, characterized in that the n-magnetic circle consists of a horseshoe-shaped Magnets with an air gap or groups of such magnets. ii. Sound transmitter according to claim i to io, characterized in that yaw consists of a magnetic circuit three-legged magnets with two air gaps or groups of such Magnets. 1: 2. Sound transmitter according to Claim i, characterized in that the leakage flux is avoided on the rims of the air gap, in that around the gap in the A shield-like electrical conductor is arranged because of the leakage flux.