GB1579947A

GB1579947A - Arrangement for fixing a shading ring of an electromagnetic core

Info

Publication number: GB1579947A
Application number: GB1694877A
Authority: GB
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Licentia Patent Verwaltungs GmbH
Priority date: 1976-04-23
Filing date: 1977-04-22
Publication date: 1980-11-26
Also published as: DE2617847A1; IT1076032B; DE2617847C3; DE2617847B2

Description

(54) AN ARRANGEMENT FOR FIXING A SHADING RING OF AN ELECTROMAGNETIC CORE (71) We, LICENTIA PATENT VERWAL TUNGS GmbH, of 1 Theodor-Stern-Kai, 6 Frankfurt/Main 70, Federal Republic of Germany, a German body corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to an arrangement for fixing a shading ring of an electromagnetic core, which ring lies with its longitudinal limbs in grooves and/or recesses in the pole face of a fixed electromagnet core, its crosswise limbs projecting beyond the pole face.

A large number of types of construction for fixing shading rings is known. German Offenlegungsschrift No. 1 764 522, for example, and German Patent Specification No. 1 464217 show constructions in which the crosswise limbs projecting beyond the pole face are fixed or held on the magnet body. In another group of constructions, for example in the construction according to German Auslegeschrift No 1 107 825 the shading ring is clamped. In another type of fixing, for example, in a construction according to German Offenlegungsschrift No 1 614 105 the shading ring is held by projecting casing parts. Finally a group of constructions is known in which the shading ring lying in the grooves is held by resilient and/or plastic deformation (German Patent Specification No 951 511).

The invention seeks to create a reliable arrangement for fixing a shading ring with very little outlay, without the shading ring being put under load by the switching transients of the magnet and without any addi tional; components or additional measures being necessary, such as gluing or deformation of the magnet plates.

According to the invention, there is provided an arrangement for fixing a shading ring of an electromagnetic core in the bore of a coil former body the arrangement comprising internal projections in the bore of the coil former body engageable on at least one side with limbs of the shading ring.

The projections may be arranged on both sides of the said limbs of the shading ring when the pole face is arranged within a coil form comprising thermoplastics and at least the projections lying on one side of the shading ring are profiled to be of wedge shape increasing in depth from outside of the bore towards the inside for facilitating insertion of the shading ring.

In this type of construction fixing of the shading ring takes place, in contrast to the previously known construction within the coil former bore. Thus the shading ring is located within an area left free by the projections of the coil former and therefore may either be loosely mounted here or may be firmly clamped by these projections or the walls of the coil former. In each case the shading ring is mounted so that impacts on the fixed magnet cannot be taken up by the shading ring and thus the danger of breakage is avoided.

A further advantage lies in the fact that additional components such as brackets or wire straps and subsequent processing for example squeezing or compression of the magnet laminations, are not necessary. The' projections are located preferably on opposite walls of the coil former bore. They may extend either only over a part of the walls of the coil former bore or may extend from the bearing point of the shading ring up to the respective edges of the coil former orifice. When the shading ring is mounted on both sides by these projections, then either the projections lying on one side of the shading ring only or the projections lying on both sides of the shading ring are profiles to be of wedge shape increasing in depth from outside of the bore towards the inside.Thus it is possible for the shading ring to be inserted into the coil former either only from one side, for example from the electromagnetic core side, or also from the other side.

Fixing in accordance with the invention takes place for example so that the shading ring is inserted into the coil former chamber from the electromagnetic core side so that the wedge-shaped projections forced away to the side during insertion of the shading ring as a result of the natural resilience of the coil former snap back into place after the shading ring reaches its final position and that the coil former is wound after the shading ring has reached its final position.

After the projections which have been forced aside during insertion of the shading ring have snapped back into place behind the shading ring the shading ring has taken up an irretrievable position. Further fixing is achieved by the fact that the coil form is now wound. The shading ring is thus absolutely irretrievably mounted as a result of the additional winding at the base of the coil. After applying the winding the magnet core is inserted into the coil former chamber so that the longitudinal limbs of the shading ring fixed inside the coil form orifice lie inside the grooves of the pole face. In order to facilitate assembly, the grooves provided in the pole face may have a trapezoidal cross-section.

When arranging the pole face within a coil form in one direction of movement, projections may serve as a stop for the shading ring and in the other direction of movement the bases of the grooves of the fixed magnet may serve as a stop for the shading ring.

With this embodiment, the shading ring is inserted into the coil former bore from the side on which there are no projections. Thus the shading ring inserted in this manner is held on the projections provided in the inner space on the one hand while from the thrust side it is held by the bases of the groove of the inserted magnet core itself. With this construction the winding may be applied before inserting the shading ring. The projections preferably have a uniform cross-section. However, they may also be wedge-shaped so that even with this construction the shading ring may be inserted from the armature side.

The arrangement in accordance with the invention for fixing a shading ring may be used preferably in switchgear in which the position of the magnet core with regard to the position of the coil former varies very ittle during the switching process.

The invention will now be described in greater detail, by way of example with reference to the drawings, in which: Figure 1 shows a side view of a coil housing; Figure 2 shows a side view of a fixed magnet core; Figure 3 shows a view of the pole face of the fixed magnet core in accordance with Figure 2; Figure 4 shows a section A-A according to Figure 1; Figure 5 shows a section B-B according to Figure 4, and Figure 6 shows a section C-C according to Figure 5.

Figure 1 shows a coil form 10 manufactured from thermoplastics and having flanges 11 and 12 arranged at its endfaces and a coil former bore 13. Figures 2 and 3 show a fixed magnet core 14 which is inserted into the coil former bore 13 of the coil form 10. The pole face 15 of the fixed magnet core 14 contains two grooves 16, 17 preferably of trapezoidal cross section for the purpose of accommodating a shading ring 18. The shading ring comprises two longitudinal limbs 19, which lie in the grooves 16, 17 in their assembled state and two crosswise limbs 20 which project beyond the pole faces 15 when assembled.

In accordance with Figures 4, 5 and 6 the coil form 10 contains a wedge-shaped projection 21 respectively on two opposite inner walls, said projection 21 reducing from the inside towards the edge of the coil former chamber 13. The said walls of the coil form orifice contain two projections 22 moreover which start from the opposite edge of the coil former chamber 13 and have a generally rectangular cross-section throughout. An area is left free between the ends of the projections 21 and 22 in which area the shading ring 18 lies.

When assembling the arrangement the shading ring 18 is initially inserted from one end into the coil former bore 13. Thus the coil form walls exhibiting projections 21 are forced apart by means of natural resilience until the shading ring 18 snaps behind the ends of the wedge-shaped projections 21 with its crosswise limbs 20. These coil form walls with projections 21 then snap back into the original position. The shading ring 18 is thus irretrievably mounted on the one hand by the ends of the wedge-shaped projections 22 and on the other hand by the ends of the wedgeshaped projections 21. By applying the winding to the coil former 10 and additional fixing of the shading ring 18 is achieved.After winding has been applied, the fixed magnet core 14 is inserted into the coil form orifice 13 from the end, wherein the longitudinal limbs 17 of the shading ring 18 move into the grooves 16 and 17 of the pole face 15.

WHAT WE CLAIM IS:- 1. An arrangement for fixing a shading ring of an electromagnetic core in the bore of a coil former body the arrangement comprising internal projections in the bore of the coil former body engageable on at least one side with limbs of the shading ring.

2. Arrangement according to claim 1, wherein the projections are arranged on both sides of the said limbs of the shading ring and at least the projections lying on one side of the shading ring are profiled to be of wedge shape increasing in depth from the outside of the bore towards the inside for facilitating insertion of the shading ring.

3. An arrangement according to claim 1, wherein when the magnetic core is arranged within the coil former body, the projections

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. side during insertion of the shading ring as a result of the natural resilience of the coil former snap back into place after the shading ring reaches its final position and that the coil former is wound after the shading ring has reached its final position. After the projections which have been forced aside during insertion of the shading ring have snapped back into place behind the shading ring the shading ring has taken up an irretrievable position. Further fixing is achieved by the fact that the coil form is now wound. The shading ring is thus absolutely irretrievably mounted as a result of the additional winding at the base of the coil. After applying the winding the magnet core is inserted into the coil former chamber so that the longitudinal limbs of the shading ring fixed inside the coil form orifice lie inside the grooves of the pole face. In order to facilitate assembly, the grooves provided in the pole face may have a trapezoidal cross-section. When arranging the pole face within a coil form in one direction of movement, projections may serve as a stop for the shading ring and in the other direction of movement the bases of the grooves of the fixed magnet may serve as a stop for the shading ring. With this embodiment, the shading ring is inserted into the coil former bore from the side on which there are no projections. Thus the shading ring inserted in this manner is held on the projections provided in the inner space on the one hand while from the thrust side it is held by the bases of the groove of the inserted magnet core itself. With this construction the winding may be applied before inserting the shading ring. The projections preferably have a uniform cross-section. However, they may also be wedge-shaped so that even with this construction the shading ring may be inserted from the armature side. The arrangement in accordance with the invention for fixing a shading ring may be used preferably in switchgear in which the position of the magnet core with regard to the position of the coil former varies very ittle during the switching process. The invention will now be described in greater detail, by way of example with reference to the drawings, in which: Figure 1 shows a side view of a coil housing; Figure 2 shows a side view of a fixed magnet core; Figure 3 shows a view of the pole face of the fixed magnet core in accordance with Figure 2; Figure 4 shows a section A-A according to Figure 1; Figure 5 shows a section B-B according to Figure 4, and Figure 6 shows a section C-C according to Figure 5. Figure 1 shows a coil form 10 manufactured from thermoplastics and having flanges 11 and 12 arranged at its endfaces and a coil former bore 13. Figures 2 and 3 show a fixed magnet core 14 which is inserted into the coil former bore 13 of the coil form 10. The pole face 15 of the fixed magnet core 14 contains two grooves 16, 17 preferably of trapezoidal cross section for the purpose of accommodating a shading ring 18. The shading ring comprises two longitudinal limbs 19, which lie in the grooves 16, 17 in their assembled state and two crosswise limbs 20 which project beyond the pole faces 15 when assembled. In accordance with Figures 4, 5 and 6 the coil form 10 contains a wedge-shaped projection 21 respectively on two opposite inner walls, said projection 21 reducing from the inside towards the edge of the coil former chamber 13. The said walls of the coil form orifice contain two projections 22 moreover which start from the opposite edge of the coil former chamber 13 and have a generally rectangular cross-section throughout. An area is left free between the ends of the projections 21 and 22 in which area the shading ring 18 lies. When assembling the arrangement the shading ring 18 is initially inserted from one end into the coil former bore 13. Thus the coil form walls exhibiting projections 21 are forced apart by means of natural resilience until the shading ring 18 snaps behind the ends of the wedge-shaped projections 21 with its crosswise limbs 20. These coil form walls with projections 21 then snap back into the original position. The shading ring 18 is thus irretrievably mounted on the one hand by the ends of the wedge-shaped projections 22 and on the other hand by the ends of the wedgeshaped projections 21. By applying the winding to the coil former 10 and additional fixing of the shading ring 18 is achieved.After winding has been applied, the fixed magnet core 14 is inserted into the coil form orifice 13 from the end, wherein the longitudinal limbs 17 of the shading ring 18 move into the grooves 16 and 17 of the pole face 15. WHAT WE CLAIM IS:-

1. An arrangement for fixing a shading ring of an electromagnetic core in the bore of a coil former body the arrangement comprising internal projections in the bore of the coil former body engageable on at least one side with limbs of the shading ring.

serve as a stop for the shading ring in one direction of movement and in the other direction of movement the bases of grooves in the electromagnetic core act as a stop for the shading ring.

4. An arrangement according to claim 1 2 or 3, wherein the projections are arranged on opposite walls of the coil former bore.

5. An arrangement according to any one of claims 1 to 4 wherein all of the projections lying on both sides of the shading ring are profiled to be of wedge shape increasing in depth from the outside of the bore towards the inside.

6. An arrangement according to any one of claims 1 to 4 wherein a wedge-shaped projection is respectively provided on the electromagnetic core side of the shading ring on each of the opposite fixing walls of the coil former bore and two uniform projections are respectively provided on the other side of the shading ring.

7. An arrangement according to any one of claims 1 to 6 wherein the projections only extend over one part of the walls of the coil former bore.

8. An arrangement according to any one of claims 1 to 6 wherein the projections extend from the bearing point of the shading ring up to the respective edges of the coil former orifice.

9. An arrangement according to claim 3 wherein the grooves provided in the magnetic core are provided in its pole face and have a trapezoidal cross-section for receiving limbs of the shading ring.

10. A method of fixing a shading ring into an arrangement according to claim 2 or any claim appendent directly or indirectly thereto wherein the shading ring is inserted into the coil former bore from the electromagnetic core side for the purpose of bilateral mounting by means of the projections when the coil former is unwound; the wedge shaped projections are forced aside during insertion of the shading ring as a result of a natural resilience of the coil former base and snap back into place after the shading ring reaches its final position and the coil former is wound after the shading ring has reached its final position.

11. An arrangement for fixing a shading ring of an electromagnetic core in the bore of a coil former body as described herein with reference to the drawings.