SU679257A1 - Electromagnetic vibrator - Google Patents

Description

(54) ELECTROMAGNETIC VIBRDTOR

f

The invention relates to technical acoustics and can be used to create devices for the excitation of: oscillations of structures and especially for multipoint excitation of oscillations of complex structures such as aircraft, in the study of their frequency characteristics.

Electromagnetic vibrators are known that contain a magnetic core, an excitation winding, a measles, and a bark suspension spring 1.

However, these vibrators have large dimensions and must be mounted on supports.

The closest to the technical essence of the invention is an electromagnetic vibrator containing a magnetic core with through coaxial holes on two opposite sides, into which a guide bush with a crust located in it, an excitation winding covering the bush and springs of the core 2 suspension are inserted.

This vibrator contains one excitation focal that allows to create the force of an electromagnet in one direction. At the same time, measles is pulled into the winding. To move the core in the opposite direction, the elasticity of the tested structure or a special elastic suspension deformed when the core is pulled into the winding is used. Therefore, this vibrator cannot create an excitation force change in the entire operating frequency range according to the required law, for example, a sinusoidal, and the vibrator efficiency is low. In addition, support is necessary for such a vibrator, which complicates operation and use.

The aim of the invention is to enhance the functionality and increase the efficiency of the converter.

Claims (2)

The goal is achieved by the fact that the vibrator is equipped with a second excitation winding and two diodes, while the windings are installed symmetrically on both sides of the middle of the core with a gap and electrically connected in series through the diodes connected in one direction, and the measles are made with a length equal to the distance between the inner surfaces mi poles-magnetic circuit. In addition, to reduce the frequency of natural oscillations of the core and limit its progress, as well as to increase the cooling efficiency of the windings, it is equipped with weights of non-ferromagnetic material, made with lugs and fixed rigidly at the ends of the core, and with a spiral coil installed between the ends of the windings . Figure 1 shows the proposed electromagnetic vibrator; in Fig.2, the section A-A of Fig.1; Fig. 3 shows the connection of the vibrator to the generator of the sinusoidal currents. The vibrator contains a magnetic core with poles 2 and 3, a guide bushing 4 of a nonmagnetic material, a winding of a forward 5 and a reverse 6 flow, connected according to measles 7 of a ferromagnetic material made of a length equal to the distance between the inner surfaces of the pole 2 and 3 magnetic cores 1. Between the contacting ends of the windings 5 and 6, a coil 8 is installed, made in the form of a tube bent in a spiral and filled with epoxy resin. The internal coil of the coil 8 has holes for cooling air to flow to both sides along the inner surfaces of the windings 5 and 6. Between the surfaces of the windings 5.6, the sleeve 4 and the poles 2.3, there are protrusions 9 (or insulating gaskets) channels 10 are formed in the form of narrow slits, having an increasing cross-sectional area as they approach the exit. At the ends of the core 7, interchangeable weights 11 and 12 are made of a non-ferromagnetic material, rigidly connected to the core-bolt 13. The loads 11 and 12 are made at the end of the fronts, against which springs 14, 15-- of the chkor suspension rest average working position. The weight of the weights is 11.12 and the stiffness of the springs 14.15 is chosen so that the natural frequency of the suspension of the core with weights is below the lower limit of the required operating frequency range of the vibrator. The generator 16 through diodes17,18 connected to the windings. The vibrator works as follows. The forward and reverse windings, respectively, 5 and 6 are powered from special generators or from a variable-voltage generator-amplifier 16 of adjustable frequency through diodes 17.18. A positive half-wave voltage, for example, through diode 17, creates a current in the winding 5, and the negative half of the diode through the diode 18 is in the winding 6, the measles 7 are driven into oscillatory motion. Due to the fact that the suspension frequency crust with 74 loads 11.12 is selected below the operating frequency of the sinusoidal current specified by the amplifier-generator, the oscillation phase of the crust lags behind the phase of current change in the windings 180, i.e. in the winding 5 to the maximum, the measles 7 will be in the extreme position in the winding 6. At the same time, the magnetic flux of the included winding 5 is almost closed along the measles 7, magnetic conductor 1 and pole 3 in the side of the open winding 6 and has a working gap between the crust 7 and the pole 2 magneto The side of the included winding 5, as a result, measles 7 is acted upon by the maximum force directed towards the included winding 5. The execution of the core 7 with a length equal to the distance between the inner surfaces of the poles 2 and 3 of the magnetic circuit 1 reduces parasitic air gaps to a minimum , the powerful force developed by the vibrator. This leads to the fact that the average position of the core at work has a stable state. During operation, the bark 7 is automatically set to the middle working position, and the springs 14 and 15 serve only to balance the weight of the bark with weights. When the core 7 is made smaller than the proposed one, the average working position of the core does not possess stability, the measles are drawn in the direction of one of the windings 5,6, and the force developed by the vibrator decreases in this case several times. When performing the length of the core greater than proposed, the vibrator does not work. To cool the vibrator when operating in an overloaded mode, compressed air is supplied to the input of the coil 8, which, entering the slot-like channels 10, cools the contact ends, the inner surfaces, outer ends and the outer surfaces of the windings 5 and 6. When using a vibrator for multipoint excitation of vibrations of complex structures Due to its relatively low weight, the vibrator can be mounted directly on the structure under study, without introducing noticeable distortions in the frequency characteristics of the structure. In this case, there is no need for cumbersome complex structures for installation of the vibrator on the support. WIW: the tori are fastened to the structure under study by the magnetic core, and the phases of the exciting force are changed by simply switching the turn-on sequence of the windings 5.6 by 180. (while the vibrators work in phase or antiphase). When using the vibrator as a shaker, weights 11, 12 are removed, and an object table is fixed on the bark, and the magnetic core is placed on the foundation. The design of the vibrator makes it possible to create and use for its writing simple, powerful, compact, variable frequency generators on thyristors. Claims 1. Electromagnetic vibrator containing a magnetic core with two squared coaxial holes in which a guide bush with a core arranged in it is inserted, a winding enclosing the sleeve, and bark suspension springs differing in that in order to expand the functionality and increase the efficiency, it is equipped with a second field winding and two diodes, with. In this case, the windings are arranged symmetrically on both sides of the middle of the core with a gap and electrically connected in series through the diodes connected in one direction, and the measles are made equal to the distance between the inner surfaces of the poles of the magnetic circuit. 2. Vibrator according to Claim 1, characterized in that, in order to reduce the natural frequency of the core and limit its stroke, it is equipped with weights of non-ferromagnetic material, made from the protrusion of w and fixed rigidly at the ends of the crust, 3. Vibrator according to Clause 1 characterized in that, in order to increase the cooling efficiency of the windings, it is equipped with a spiral coil installed between the front windings. Sources of information taken into account in the examination 1. Rekus GG Vibrators with electromagnetic drive (review). Ed. TSNIIESTROYMYSH, M., IV series, 1970, p. 4-8. 2. Copyright certificate 238648, cl. G 05 F 7/00, 1967 (prototype) .. // JL Yu cpus / Y ////////////// V //////////// U5. five