RU2466800C1 - Electromagnetic vibrator of torsional vibrations - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: vibrator contains the first and the second coaxial multipole magnetic conductors with a gap between their poles. Poles of the first magnetic conductor are provided with exciting coils connected to source of controlled direct-current voltage. Design of the second magnetic conductor provides it rotation by drive motor. In the gap between magnetic conductors with poles there is a cylinder armature with possibility of oscillation about centre is located, on the armature there are its magnetic conductors attached. Armature is attached to vibrating object.

EFFECT: providing possibility of operational and independent control of frequency of torsional vibrations by change in rotation speed of drive motor, and of their values - by current change in exciting coils.

5 dwg

Description

The invention relates to the field of vibration technology, in particular to torsion vibrators, and can be used in mechanical engineering to relieve residual mechanical stresses in long shafts, for vibration exposure to liquid and granular media, etc.

A device is known for creating torsional moment on a rotating product containing a fixed magnetic circuit with an excitation winding, in the gap between the poles of which is placed a gear disk connected to the part from electrically conductive material. When the disk rotates, its teeth alternately fall into the gap between the poles of the magnetic circuit, while a eddy current is induced in the body of the teeth, and an alternating force that creates a torsional moment acts on the tooth, disk and part. The frequency of the moment is proportional to the frequency of rotation of the part with the disk and the number of teeth on the disk [1].

The disadvantages of this solution, limiting the scope of its application and reducing technical characteristics, are significant losses in the disk caused by eddy currents in its teeth, and the inability to control the frequency of torsional moment without changing the speed of rotation of the part.

Known adopted for the prototype resonant engine of torsional vibrations [2].

It contains a multi-pole stator magnetic circuit with field winding coils placed at its poles, an alternating voltage source for exciting a magnetic field at the poles, a multi-pole rotor magnetic circuit with permanent magnets at its poles and an elastic element mounted between the rotor and the stator. At the poles of the rotor are mounted pole pieces made of ferromagnetic material. When the excitation winding coils are supplied with alternating current by the stator poles and the rotor poles, a force is created that determines the torsional moment transmitted by the rotor to the vibrated object - the load. The magnitude of the torque can be controlled by changing the magnitude of the alternating current in the stator coils.

The most effective vibrator operates in the resonant mode, which is ensured when the frequency of the current in the coil is equal to the natural frequency of the oscillations of the mechanical system. The natural frequency is determined by the moment of inertia of the vibrator armature with the vibrating load and the stiffness of the applied elastic element.

The disadvantage of such a vibrator is that at frequencies other than its own, the vibrational moment of oscillation applied to the rotor with a load drops sharply. This limits the applicability of the solution. Also, this design is quite complicated, this is due to the need to use a set of elastic elements and replace them to ensure effective vibrations of the required frequency.

The objective of the invention is to increase the technical characteristics of the torsional vibration vibrator, expanding its scope and reducing the cost of its operation.

The technical result consists in providing the possibility of operational and independent control of changes in the frequency and magnitude of torsional vibrations. A change in the magnitude of the torsional moment is achieved by a change in the current level in the coils of the field winding, and a change in the frequency of the moment is achieved by a change in the speed of rotation of the moving magnetic circuit by the drive motor. The technical result is achieved by the exchange between the kinetic energy of rotation and the magnetic energy of the vibrator system without using elastic elements in the design, which increases the reliability, durability and efficiency of converting the energy consumed into the energy of the generated torsional vibrations.

The proposed technical solution contains the first and second coaxial multipolar magnetic cores with a gap between their poles. At the poles of the first magnetic circuit are placed the field winding coils, which are connected to a voltage source with an adjustable constant voltage. The second magnetic circuit is made with the possibility of rotation of the drive motor. In the gap between the magnetic cores with the poles, a cylindrical armature is placed with the possibility of angular oscillatory motion, on which the armature magnetic cores are fixed. An anchor is attached to a vibrating object.

Distinctive features of the prototype are the second magnetic circuit rotating with a given frequency and the introduction of a cylindrical armature into the magnetic system between the first and second magnetic circuits with the possibility of its oscillatory motion, in which the magnetic circuits are fixed opposite the poles of the first magnetic circuit, while the field winding coils are connected to an adjustable constant voltage source . To increase the energy conversion of the vibrator, expressed in an increase in the generated force, an electric inductor can be included in the circuit between the DC voltage source and the exciter winding of the vibrator.

The design of the vibrator and its operation are illustrated by the drawings:

figure 1 and 2 is a transverse and longitudinal section of the vibrator, figure 3 is a fragment of a linear sweep of the magnetic system of the vibrator, figure 4 is a diagram of the current of the field winding and the corresponding torsional moment of the vibrator in the interval of the pole division of the magnetic circuits, figure 5 is a power supply circuit field windings.

A magnetic circuit 2 is fixed in the housing 1 (Figs. 1, 2), with the coils 3 of the field winding at the poles 4. A magnetic circuit 5 with poles 6 is located concentrically with it, the number of which is equal to the number of poles 4. In the gap and between the poles 4 and 6 there is a cylindrical non-magnetic armature 7, on which the magnetic circuits 8 of the anchor are fixed, separated from the poles 4 by a technological gap, to provide angular oscillatory motion of the armature 7 with the magnetic circuits 8 relative to the poles 4. The magnetic circuit 5 and the anchor 7 are separated from the housing 1 by bearings to provide the rotation of the magnetic circuit 5 by the drive motor and the oscillatory movement of the armature 7 relative to the poles 4. Racks 9 connected to the armature 7 are passed through the holes in the housing 1 and are rigidly connected to the part 10, to which the torsional moment of the vibrator is transmitted.

The vibrator works as follows. The magnetic circuit 5 rotates with an angular velocity ω using a drive motor (not shown in FIGS. 1, 2). When the field winding is connected to a source with an adjustable constant voltage (not shown in Fig.), Current flows through the coils 3 of the field winding. In this case, a flow passes through the gap between the poles 4, 6. When the magnetic circuit 5 is rotated, its poles periodically overlap the magnetic circuits 8 of the anchor (Figs. 2, 3), which leads to a periodic change in the magnetic conductivity G (x) between them and the creation of force between the poles 6 on the rotating magnetic circuit and the magnetic circuits 8:

where F = iw is the magnetomotive force of the field coil coils, with the number of turns w, necessary to create a magnetic field armature in the gap between the poles and magnetic circuits.

The value of the magnetic conductivity G (x) is determined by the position x of the poles 6 of the rotating magnetic circuit 5 relative to the magnetic circuit 8 of the armature. The direction of movement x of the anchor is shown in Fig.3.

At 0 <x <c (Fig. 3), where c is the width of the poles in the x direction, the conductivity G (x) increases due to an increase in the overlap area of the poles 6 and the armature cores 8, and for c <x <2 s, G ( x) decreases. This leads to an increase or a decrease in the inductance of the excitation winding, and the EMF of motion is induced in it, which results in a change in the excitation current and the generated force, and is also accompanied by the appearance of an alternating torsional moment M = Pr, where r is the external radius of the armature.

, где Ld - индуктивность дросселя в цепи обмотки возбуждения и L₀ - ее индуктивность при х=0.Figure 4 shows diagrams of changes in the relative values of current i and moment M in the interval of creating an alternating force value from position x. Diagrams are shown at various relative inductance values.

where Ld is the inductor inductance in the field circuit and L ₀ is its inductance at x = 0.

The alternating character of the force applied to the magnetic circuit of the armature ensures the action of the torque M on the armature.

For 0 <x <c, the action of the moment M leads to acceleration of the rotating magnetic circuit 5, and for c <x <2s, it slows down and transforms magnetic energy into mechanical energy and mechanical energy into magnetic energy, respectively.

Thus, in the proposed solution, during the interval 0 <x <2s, corresponding to the period of change of the moment M, a periodic exchange is made between the energy of the magnetic field of the vibrator and the mechanical energy of rotation of the magnetic circuit 5. From the graphs in figure 4 it follows that the increase in inductance L _{d of the} inductor (Fig. 5) and the corresponding value of α leads to an increase in the average value of the moment at the half-period of oscillations, while the ripple of the excitation current decreases.

The frequency of the torsional moment is proportional to the number of poles n on the magnetic circuit and the frequency of rotation of the magnetic circuit 5 by a drive motor.

The magnitude of the moment depends on the current in the coils 3 and can be controlled by the magnitude of the voltage using a controlled rectifier or DC / DC converter.

Thus, the proposed technical solution, in contrast to the prototype, allows for relative independent regulation of the magnitude and frequency of the generated torque. Moreover, unlike the known resonant vibrators, including the prototype, in which the energy exchange occurs between the kinetic energy and the strain energy of a mechanical spring, in the proposed solution, the role of the "spring" is played by the energy of the vibrator’s magnetic field, and the necessary energy exchange is provided when the frequency and magnitude change created torque. This solution allows you to expand the possibilities of using the vibrator in modes that require rapid changes in the magnitude and frequency of the torsional moment, increase the efficiency of converting the energy consumed into energy generated by the vibrator, and reduce costs during its operation.

Information sources

1. USSR Copyright Certificate No. 992103 V06B 1/04. Publ. 01/30/83. Bull. Number 4.

2. Patent for utility model of the Russian Federation No. 99996171, B06B 1/04. Publ. 12/10/10 g.

Claims (1)

An electromagnetic torsional vibration vibrator containing the first and second coaxial multipolar magnetic cores with a gap between their poles, excitation coil coils are placed on the poles of the first magnetic circuit, and their power supply, characterized in that the second magnetic circuit is rotatable, is placed in the gap between the poles of the magnetic circuit with the possibility of angular oscillatory motion of a cylindrical anchor, on which opposite the poles of the first magnetic circuit fixed magnetic circuits of the armature, and the coil quipment excitation are connected to a regulated source of DC voltage.

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