DE4210287C1 - EM oscillation inducer with U=shaped core for windings - has measurement value pick=up for high efficiency but preventing armature in air gap impacting shanks of magnetic core - Google Patents

Abstract

The U-shaped magnetic core (1) for two identically shaped electromagnets has limbs (2) terminated by pole surfaces. An armature (5) is provided separated by an air gap from the pole surfaces of the magnetic core. The armature vibrates in the air gap relative to the pole surfaces. A measurement value pick-up (6) is provided for determining the actual value from a vibration parameter, and is arranged in an axis (7) parallel to the limbs and running vertical to the pole faces. The pick-up (6) is interposed between the limbs to have the same distance to each of them. The pick-up can be insertable to measure amplitude, speed and/or acceleration. USE/ADVANTAGE - Compact design, and can be installed for determining actual voltage as reliably as possible, for regulation. Conveying fluent material and small components. Driving sieve, separator or distributor.

Description

The invention relates to an electromagnetic vibration exciter according to the preamble of claim 1.

Such an electromagnetic vibration exciter is from the DE-AS 14 47 330 known. The vibrator has two masses, which are coupled together by springs and by a Electromagnetic system and an armature are excited to vibrate. An inductive sensor is attached to both vibrating masses, the encoder is attached to the side of the masses. At a The encoder detects the collisions of the masses Bounce vibrations and causes an interruption of the Main power supply. The encoder is not used for control of the current and for setting an optimal vibration amplitude.

In DE-PS 40 37 994 is an electromagnetic Vibration exciter described. This patent specification is not an indication to see how the vibration parameters Amplitude, speed and acceleration can be recorded.

Electromagnetic vibration exciters are known as so-called Magnetic vibrators in various designs for driving of vibrating conveyor troughs for bulk goods and small parts as well as the Drive of sieves, separators or allocation devices used.

Electromagnetic vibration exciters set Dual mass vibration system, in which the magnet system and the armature swing in opposite directions. The magnet system and the anchor are usually coupled with each other via springs and by a Air gap spatially separated. It must be at all times there is a (minimum) air gap during the vibrations, so that the magnet system and anchor do not collide. Vibrators are usually single or double Mains frequency operated.  

The natural or resonant frequency shifts with increasing Mass of the two-mass vibration system towards smaller values. In A resonance curve becomes dependent on the drive frequency run through, which is flatter, the greater the damping. Operation of the vibration exciter is in the resonance range all the more critical or unstable with regard to the vibration amplitude, the lower the damping. On the other hand, there is little Damping the advantage of a small power loss.

The aim is to create a vibration generator with a constant amplitude and the smallest possible distance between the magnet system and the armature  to operate, because the achievable efficiency is the greater, depending the minimum air gap is kept smaller.

To the vibration exciter with the smallest possible To operate the minimum air gap, it should be controlled and consequently also - to record the relevant actual values of the Vibration system - be equipped with a sensor.

The invention has for its object one with Sensor equipped electromagnetic To create vibration exciter in which the transducer Measurement of amplitude, speed and / or acceleration is used and is arranged so that it with respect to the outer dimensions of the Vibration exciter installed as space-saving as possible and as possible can be used reliably for actual value acquisition for a control system.

This task is solved by an electromagnetic Vibration exciter according to claim 1.

This arrangement of the transducer has an advantageous effect from that it is located at a location where a reliable Measurement of the vibration parameters amplitude, speed and Acceleration is guaranteed. Especially if in the context of Installation tolerances and due to disturbing vibrations of the anchors not exactly vibrates parallel to the pole faces or during the Vibrating light side tilting movements comes the arrangement of the transducer within the Vibration exciter is of great importance. Because if the Sensor, for example, on an outside of a pole face would be arranged in the previously described case depending Inclination of the armature different actual values for the amplitude detected; with these values would be an optimal regulation, in which the Width of the minimum air gap is kept as small as possible, unfavorable.

In addition, with an arrangement of the transducer between the Legs of the U-shaped magnetic core advantageous that the Outer dimensions of the vibration exciter can not be enlarged. Finally, the sensor is special in this arrangement well protected against external influences.  

Further advantageous designs can be found in the subclaims remove.

The invention is described below using an exemplary embodiment, from which further features, details and advantages result, described in more detail.

Show it

Fig. 1 shows a U-shaped magnetic core and an armature of an electromagnetic oscillation exciter,

Fig. 2 shows the electromagnetic vibration exciter according to Fig. 1 with a slightly tilted armature in longitudinal section and

Fig. 3 shows the electromagnetic vibration exciter with a tilted armature in cross section.

In Fig. 1, an electromagnetic vibration exciter with a U-shaped magnetic core ( 1 ) with a rectangular cross-section and with two legs ( 2 ) of the same design is shown, each with a rectangular pole face ( 3 ), which has small recesses at the corners and are each surrounded by a coil winding ( 4 ). The recesses that extend over the entire length of the legs ( 2 ) prevent damage to the coil windings ( 4 ) during the manufacturing process. The magnetic core ( 1 ) has a rectangular base in the region of its horizontal section connecting the two legs ( 2 ).

In addition, the vibration exciter has an armature ( 5 ), which is attached to the magnetic core ( 1 ) so that it can vibrate via spiral springs (not shown), and a measurement sensor ( 6 ), which is only sketchily indicated, which is used for detecting the amplitude, speed and acceleration of the armature ( 5 ). is determined (measurement of the vibration parameters). There is always an air gap between the armature ( 5 ) and the magnetic core ( 1 ). When an alternating current flows through the coil windings ( 4 ), the armature ( 5 ) is set in oscillations which are carried out perpendicular to the pole faces ( 3 ). So that the armature (5) does not hit the magnet core (1), a minimum air gap width, the efficiency of the vibration actuator must be maintained even at maximum deflection (in the direction of the magnetic core (1) between the armature (5) and the magnetic core (1). It is particularly large if this minimum air gap width is kept small. In order to achieve the highest possible efficiency, it is advisable to regulate the vibrations. For this purpose, the transducer ( 6 ) is necessary, which records the actual values of the vibration parameters and does not show them to you AC power supply.

Different types come into consideration as measuring sensors ( 6 ), which operate according to different measuring principles. For example, it could be an inductive measuring principle; in this case a change in inductance - caused by the movement of a part with high permeability - is used for the measurement of the vibration parameters. In such an embodiment, the coil could be fastened, for example, inside the transducer ( 6 ) between the legs ( 2 ), the vibration of the armature ( 5 ) would cause a change in the inductance of the coil.

Furthermore, a measuring principle can be used in which a voltage induced in a coil by the movement of a magnet is used to measure the vibration parameters. For this purpose, for example, the coil could be fixed in the transducer ( 6 ) between the legs ( 2 ) and the magnet on the armature ( 5 ).

Furthermore, a measuring principle is conceivable in which a spring is arranged between the magnetic core ( 1 ) and armature ( 5 ), the spring force of which is dependent on the amplitude of the vibration and which acts on a force measuring device within the measuring sensor ( 6 ). Such a force measuring device could be equipped with a strain gauge, which is pulled apart to a greater or lesser extent depending on the amplitude. These strains could be measured with the aid of an electrical signal, which could be used to determine the vibration parameters.

Finally, a measurement based on the piezo effect could be applied; in this case would be in the force measuring device a crystal that would be affected by the vibrations of the armature  and the correspondingly large one depending on the amplitude Tensions would be available.

The transducer ( 6 ) is cast in a plastic mass located between the legs ( 2 ). If it is no longer functional, it is exchanged together with the magnetic core ( 1 ), which is a relatively simple operation.

The transducer ( 6 ) lies in an axis ( 7 ) that runs parallel to the two legs ( 2 ), is equally far away from both legs ( 2 ) and at the same time crosses the center of gravity of the rectangular base of the U-shaped magnetic core ( 1 ) .

Figs. 2 and 3 illustrate the advantage of this arrangement. Two positions of the armature ( 5 ) in relation to the magnetic core ( 1 ) are shown in the figures (the air gap width is chosen to be particularly large because of the better representation). In these positions, the armature ( 5 ) is not in the desired parallel position to the pole faces ( 3 ), instead it is arranged in an inclined position with respect to the pole faces ( 3 ). The positions shown are to be understood as "snapshots" of different times during the vibrations. The same actual values for the amplitude ( 8 ) are always measured by the sensor ( 6 ) for the positions of the armature ( 5 ) shown. If the transducer ( 6 ) were laterally displaced at a different location, the result would be different values for the actual value of the amplitude ( 8 ) for each of the positions of the armature ( 5 ), which would regulate the vibration exciter - especially if the vibration was minimized Minimum air gap width is sought - would complicate.

Because the vibration exciter is constructed symmetrically and the armature ( 5 ) is attached to the magnetic core ( 1 ) by means of spiral springs (not shown) by means of symmetrically arranged brackets (not shown), only oblique positions with respect to the longitudinal or transverse axis of the armature ( 5 ) can be expected. as exemplified in FIGS. 2 and 3. The transducer ( 6 ) is therefore most conveniently arranged in the axis ( 7 ), because the described misalignments do not affect the measurement result in this axis ( 7 ).

Claims (6)

1. Electromagnetic vibration exciter with a U-shaped magnetic core with two identically designed electromagnets each having a pole face, with an armature separated by an air gap from the pole faces of the magnetic core, the armature vibrating in the air gap relative to the pole faces and A transducer for recording the actual value of a vibration parameter is arranged in an axis running parallel to the legs and perpendicular to the pole faces, characterized in that the transducer ( 6 ) is inserted between the legs ( 2 ) and to each of the two legs ( 2 ). has the same distance and that, instead of the measured value pick-up ( 6 ) for recording the actual value of a vibration parameter, a measured value pick-up ( 6 ) can be used for recording the actual value of several vibration parameters. 2. Electromagnetic vibration exciter according to claim 1, characterized in that the axis ( 7 ) also extends perpendicularly through a line which represents the shortest connection between the centers of gravity of the pole faces ( 3 ). 3. Electromagnetic vibration exciter according to claim 1 or 2, characterized in that the transducer ( 6 ) contains a coil, the inductance of which changes as a function of vibration movements of the armature ( 5 ), and that the vibration parameters are determined from these changes. 4. Electromagnetic vibration exciter according to claim 1 or 2, characterized in that the transducer ( 6 ) contains a coil in which, depending on vibrations of the armature ( 5 ) voltages are induced by a resonating magnet, and that the vibration parameters are determined from these voltages will. 5. Electromagnetic vibration exciter according to claim 1 or 2, characterized in that the transducer ( 6 ) contains an electrical force measuring device which detects amplitude-dependent changes in spring force of a spring arranged between the magnetic core and armature and that the vibration parameters are determined therefrom. 6. Electromagnetic vibration exciter according to one of the preceding claims, characterized in that the transducer ( 6 ) is cast in a plastic mass located between the legs ( 2 ).