DE1806245A1 - Electromagnet - Google Patents

Description

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Oct. 21, 1968 fr.gö 3035

SIEMAG Feinmechanische Werke GmbH, 59Qi Eiserfeld / Sieg

Electromagnet

The invention relates to an electromagnet with a magnet armature arranged movably within the magnet coil, the end faces of which are correspondingly adapted to the shape of the respective opposite end faces of the armature counterparts. G

_Φ frequencies in the manufacture of electromagnets for high switching is always the problem, low in possible to achieve moving anchor masses still relatively high anchoring forces; the greatest possible force-mass ratio must therefore be achieved.

With electromagnets of a previously known type, the required high switching frequencies can be achieved with the lowest possible Do not reach the magnet weight because either the moving armature masses are too large or the armature pulling forces that can be achieved are too low. Since an optimal force-mass ratio should be achieved with minimal outer magnet dimensions, only small leakage fluxes may occur within the magnet system.

The invention is therefore based on the object to provide an electric magnet for high switching frequencies "of reaching an optimum power-to-mass ratio with minimal magnetic external dimensions and is particularly suitable for operating the printing wires of mosaic printers.

According to the invention , the object is achieved in that the armature counterparts in the area within the magnet winding

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ment protrude and that the end faces of the between the armature counterparts moving magnet armature "are different in size, and have the same shape to the opposing

jared
over lying anchor mosquitoes. One end face is expediently designed as a circular ring surface and the other as a conical jacket surface.

According to an advantageous embodiment of the invention, one anchor counterpart is arranged to be adjustable. Preferably, the working air gap is at the point within of the magnet system at which the optimally achievable force is achieved. This point is a bit outside the center of the magnet system.

The invention is based on an embodiment shown in the drawing, which relates to an electromagnet related to the actuation of the pressure pins of a mosaic printer, explained in more detail

1 shows a cross section through the electromagnet according to the invention,

Fig. 2 shows the induction distribution of the armature and

3 shows a further exemplary embodiment of the electromagnet according to the invention.

The winding 2, which is surrounded by the housing jacket 3, is applied to the cylindrical coil core 1. The yoke part 4 adjoins one coil core side 1 and the yoke part 5 » ⁿ · n · within the yoke part k adjoins the other. the adjustable anchor counterpart 6 is arranged. For this purpose, the yoke part k and the anchor piece 6 are provided with a thread 9, with which it is possible by screwing the anchor counterpart 6 into the area within

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of the coil core 1 to set the exact air gap Hl. Within the armature counterpart 6, a tube 7 made of non-magnetic sliding material is arranged, in which the print needle 8 is guided. The yoke part 5 »that to avoid leakage flux and to reduce the Armature protrudes into the coil core 1, is thus designed at the same time as an armature counterpart. Between the two In the coil core 1 protruding armature counterparts 5 and 6, the armature 10 is arranged, which is the one in each case opposite anchor counterparts 5 and 6 corresponding Has surface shape. The anchor here points to one I.

Side a circular surface and on the other side a conical surface on.

The force with which the armature of the electromagnet is attracted is calculated using the well-known approximation equation

(B ₁ ) ² .
^F l "(5000) ^{2 A} l

If, as indicated in the present example, the yoke parts k and 5 or the armature counterparts 5 and 6 are inserted into the inner coil part to avoid leakage fluxes and the movable armature 10 is thus arranged within the two armature counterparts 5 and 6, it can normally only move move when there is no magnetic equilibrium on either side. There must therefore be a differential force, ie that towards the side towards which the armature 10 is to move, a greater force must be effective than on the other side. After considering the above formula, this can be achieved either by means of magnetic inductions of different sizes or surfaces of different sizes on both armature faces. But since the magnetic induction is closely related to the surface via the equation 5 = Β, and 1 at con-

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18062A5

constant excitation of the winding of the magnet due to the inventive design of the armature counterparts 5 and 6 is also approximately constant, B and A change inversely proportional to each other.

^A l

By enlarging the force line exit area the side opposite the yoke part 5 results in differently large tightening forces. Will the one surface increased by the fact that on the yoke part 5 opposite lying side uses a conical anchor shape, the effective force in the axial direction of the armature 10 is only depends on the component of induction acting in the axial direction. In Fig. 2 is the anchor for this purpose 10 with the corresponding induction distributions specified in more detail. There is a on the conical surfaces axial induction of

sin

¹ =

^sin

► B.

This results in a force of

<v)

w) ^{2 (B} - ' ² ■ ²

A. F = "2 ' A ₀ = i A". Sin

(5OOO) ² . (5OOO) ²

^A 1

^F 2 = ^F l 7Γ ^sin
A 2

When using the specified in the embodiment Surface shape results for

A = (d? - d ^l ) _t II

and for

^A 2 = ^(d l · ⁱ l - ^d 2 *
there

V ² = V ² = sin *,

will

A "=

ft. sin

= A. 1

If you put this expression in the equation for F, then surrendered

F. = F .. sin ² K

The differential force F_ now results as follows;

F = F -F = F -F sin κ Dl 21 1 ^Λ

F _D =

With this training and arrangement of the anchor is at the same time met the requirement with the lowest possible

Mass of the anchor, which is determined by the conical design size
form results in attaining a force.

An optimal force-mass ratio is thus achieved. Since the armature 10, as previously proven, strikes the armature counterpart 6 with a greater force, the smaller it is is the angle of the conical armature 10, the air gap applies

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All working _{air gap t} although the total air gap of the magnetic circuit and thus also the magnetic resistance always maintain the same value even when the armature is attracted. On the basis of experiments relating to the location of the
The air gap hl can be determined * that this is decisive for achieving the optimal force of the armature 10. The air gap hl is therefore arranged somewhat outside the center of the coil core 1, at which the optimal force is achieved.

The conical anchor 10 is on a tube 11 through
Impact on the pressure needle 8 firmly applied. The print needle 8 is bent at its outer non-printing end and attached to a spring 13 by insertion. The spring 13 », which is locked by means of the clamping disc lk , is used to return the armature 10 to the starting position.

To limit the return stroke, a disk 15 is attached to the end of the tube 11. The stroke between the yoke part 5 and the disc 15 is now designed so that it is smaller than the stroke h 1 between the armature counterpart 6 and
Anchor 10, so that the anchor IO cannot hit the anchor counterpart

Since the working stroke h 2 of the print wire 8 is less than

the working air gap is h 1, is a limit stop of the armature 10 in the axial direction is not required.

When the coil 2 is switched off, the armature 10 is returned to the starting position or the disk 15 by the spring

brought to the stop with the stop piece 12 made of damping material. The retaining washer l6 is set so that the conical side of the armature 10 cannot impinge on the yoke part 5.

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In the embodiment of the electromagnet described so far, the pressure needle is actuated 8 according to the working current principle, i.e. that the print needle 8 is moved * Another advantageous embodiment of the electromagnet according to the invention works after the reversal of the principle described so far, the closed-circuit principle o The armature 10 is in this Arrangement in the non-printing state of the print needle 8 pulled against the spring force of a spring 13 « In relation to the embodiment shown in Fig. 1, in the second embodiment (Fig. 3) the " Armature 10 reversed and the spring 13 also acting in the opposite direction. After switching off the excitation current of the electromagnet, the print needle 8 with the energy stored by the spring 13 in the direction moved to the print plane. The spring 13 is firmly clamped between the ring and the shoulder ring 17 »through the bore of the attachment 17 ragl a stop piece 12 made of elastic Materiaxj that by means of a threaded pin l6 can be adjusted. The stop piece 12 is now set so that when the magnet is excited the The magnet armature 10 cannot strike the armature counterpart 5

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Claims (1)

SIEMAG Feinmechanische Werke GmbH., 5904 Eiserfeld / Sieg Patent claims Ie electromagnet with a movable inside the magnet coil arranged magnet armature, the end faces of which have the shape of the respective opposite end faces the anchor counterparts are adapted accordingly, characterized in that P that the anchor counterparts (5 + 6) in the area within the magnet winding (2) protrude and that the end faces of the armature counterparts (5 + 6) moving magnet armature (10) are different in size 2 «electromagnet according to claim 1, characterized in that the one end face of the armature (10) as Annular surface and the other as a conical surface is trained. . 3 »electromagnet according to claim 1 and 2, characterized in that one anchor counterpart (5) or (6) is adjustable is arranged « 009821 / 130A Blank page