DE1106380B - Application of the process for the production of bodies from solvent-free synthetic resins hardened by polymerisation by centrifugation in a mold - Google Patents

Description

Application of the process for the manufacture of bodies from by polymerization hardening, solvent-free synthetic resins by centrifuging in a form It is known, body made from polymerisation hardening, solvent-free synthetic resins with embedded metal parts of any shape by means of centrifugal force centrifuging in a mold, with the synthetic resins in the mold hardening.

The invention consists in the use of this method for embedding of electrotechnical, in particular high-voltage technical apparatus and devices as well as parts thereof using one without splitting off volatile constituents curing low-pressure resin as synthetic resin.

The teaching according to the invention offers the possibility of complete electrotechnical, in particular high-voltage technical apparatus and devices or complete parts thereof to be produced in one cast, even if the metal parts to be embedded are complicated shaped or particularly large. This generally comes with an outer shape because there is a stable. Inner surface adjusts due to centrifugal forces. Any gas inclusions that may be present can escape on this inner surface as long as it is the synthetic resin has not yet hardened. When using synthetic resin that is When hardening shrinks, there is the further advantage that none of them are enclosed by synthetic resin Moldings are present that could otherwise only be removed with difficulty. The advantages of the invention in impregnation and embedding are particularly striking a coil. When impregnating, so that all cavities can be filled, a relatively low-viscosity synthetic resin can be used. So far it has been extremely difficult if not impossible, the low-viscosity impregnation resin during the polymerization to hold in the coil without partially flowing out again. According to the invention, however can not only impregnate with the same resin, but in spite of the thinness all embedding of the coil can be made. The additional Effect on that, due to the centrifugal force, the resin under a certain amount Overpressure is forced into the cavities to be filled, so that one often can do without the usual vacuum treatment.

It has been shown that the polymerization starts with the low pressure resin are not adversely affected during the spin cycle. It can even be relatively large Quantities for curing beneficial additives, so-called active admixtures, be added without a detrimental to the hardening process Segregation would occur.

It is not necessary that the starting material is liquid monomer is used. It can also be used non-polymers, provided that the starting material is so fluid that when it is spun, all cavities are in shape and embedded Metal parts. So it is also not necessary that the starting material is homogeneous. Rather, parts that are in a solid aggregate state can also be a component be a mixture that is flowable in its entirety. So far as flowable Material is a mixture of substances at least so approximately the same specific Weights used so that the rotational movement does not cause segregation differs Such a material does not consist of a single known chemical substance existing material regarding behavior in the course of the present proceedings. However, if in special cases it is a question of the spaces to be filled to be filled with material of different quality according to certain laws, then under certain circumstances this can still be done in a spinning process, if different suitable for the materials of different composition specific weights can be provided. In such cases it can be, for. B. as flowable material a mixture of such substances of different specifics Weights are used and the arrangement is made as well as specific Weights and the proportions of the substances in relation to one another at the be graded that the predetermined material component for a certain space the greater the radial displacement, the greater the specific weight this space is from the axis of rotation. In such cases the The centrifugal process automatically separates the mixture into the individual V-material components according to the gradation of the specific weights instead of such. that the material component with the greatest specific weight located in the furthest from the axis of rotation accumulates in distant spaces, whereas the material components with lower specific Weight are deposited in the spaces closer to the axis of rotation. Because the volume of the individual spaces to be filled is known. so can the required Material quantity can be predetermined. If it is z. B. is about fixed, in the intended implementation of the process is not in a flowable state To deposit substances in spaces closer to the axis of rotation than the rest of the material, then a mixture can be used as the flowable material, which except These solid substances have a liquid material component of greater specificity It is considered to be that of solid substances. If, on the other hand, it is z. B. about embedding electrical components such. B. of capacitor plates, to achieve an increased dielectric constant on the outer layer, then can after inserting the components into the mold in the predetermined arrangement in the rotating mold introduced a flowable material for the formation of the embedment which apart from nutty material components have a lower dielectric constant still in a predetermined amount of solid substances with a correspondingly higher dielectric constant has, the specific gravity of which is greater than that of the liquid material component is so that the solid matter is deposited in the most distant spaces from the rotation will.

Spaces that are not to be filled with material can be counteracted by filling Access to material during spinning must be protected. So it doesn't stand either : in the way, in one and the same centrifugal process different not through with each other insert the material to be joined objects in the same mold and treat at the same time when these items are arranged by appropriately and designed spacers are separated from each other, which at least to the with the flowable material in contact with the adhesion of the have an obstructive surface texture. Spacers, which do not meet the latter requirement from the outset. through a surface treatment, z. B. by painting, at least in the appropriate places in the appropriate Form must be transferred to any adherence of the flowable material at these points to prevent. On the other hand, you can also use the same tools to achieve that z. B. only those inside each object to be treated, not closed spaces are filled with llaterial, so z. B. in treatment electrical coils the spaces between the windings as well as in general all porosities and the like Zeveckweise flowable material based on synthetic resin used. However, it can be If the process is carried out appropriately, completely closed cavities with material can also be used fill if the factors involved in the formation of these cavities part of the The object cannot all be inserted into the casting mold from the outset. but with gradual implementation of the process sul; cessives in the appropriate order be introduced. The process is then carried out in such a way that initially in one First level, the spaces furthest from the axis of rotation with flowable Material filled and this at least to such an extent converted into a solid state is that it is dimensionally stable before the second stage of the process is carried out. After carrying out individual process stages, it can then initially be carried out in a respective one Intermediate treatment, the design of spaces to be subsequently filled in the predetermined Be influenced in a manner before the next stage of the procedure is initiated.

However, it can also be done by performing the procedure in stages an optional build-up of the material in the spaces to be filled in the form of sedimenta. Rtly arranged fabrics of different nature can be achieved by A flowable material is poured into the casting mold in at least one process step becomes, which after conversion into the solid state has a different nature than the material used in the other process steps. In this way it is also possible to have such an intermediate layer in the finished object to replace a cavity by removing the material after performing the last stage of the process by a material that does not affect the other material Treatment is removed from this area again. For such a thing again afterwards material to be removed, a material with a lower melting point can be used. so that it can be removed again by melting it out. Analog can, however also the removal by treating the relevant part of the material by means of one for that specific solvent. what just this one stuff dissolves without attacking the other materials.

The procedure is not based on the use of a mold when Centrifugal casting process limited to the usual horizontal axis of rotation. Much more other positions of the axis of rotation can also be used to advantage in order to achieve different Designs of the surface facing the free axis of rotation of the filled Materials to achieve. So z. B. with provision of a vertical axis of rotation achieve such free boundary surfaces of the filled material from below upward a predetermined extent-continuously increasing radial distance from the axis of rotation.

In many cases it is advisable to keep the centrifugal chamber under excess pressure or, in contrast, to keep it under vacuum pressure or with an air-free, z. B. to provide an inert atmosphere. The process can be carried out in such a way Easily adapt regulations. because the mold is hermetically sealed to the outside and means can be arranged to suck air or gases out of the casting mold or to keep it under overpressure. Working in a vacuum is especially important to to ensure a bubble-free filling of the spaces with the flowable material, what in particular for the improvement of the dielectric properties of the material matters. Even in the case of carrying out a polymerization within The mold is working in a vacuum or in an inert atmosphere to prevent it unwanted oxidations or depolymerizations may be of importance.

The method according to the invention is shown in the drawing, which some embodiments of various casting molds and manufactured in these or objects in the process of being produced, described.

FIGS. 1 to 8 each show an exemplary embodiment in a vertical central longitudinal section.

In the embodiment according to FIG. 1, a cylindrical mold is used as the casting mold Tube 1 with a horizontal axis. which serves as an axis of rotation, is provided. on Needs details regarding the design of the drive and the material supply not to be entered here, since the same relationships are involved in this regard acts like the known application gels of the centrifugal casting process. z. B. for making tubes from molten introduced metal.

In the tube 1, an electrical coil 2 is inserted, the outer diameter of which corresponds to the inner diameter of the tube l, so that the coil on its whole The circumference lies snugly against the pipe wall. The coil is against relative displacements and rotations relative to the tube 1 secured by suitable measures. Then the tube is driven around the axis of rotation with the spool at the predetermined speed set in continuous rotation.

Then flowable material, which is used to produce a Embedding the coil is intended. introduced into the tube in the usual way, e.g. B. in the form of a liquid monomer or a liquid prepolymer of the same based on synthetic resin. As a result of the rotation, it is deposited, as in the centrifugal casting process generally known, the flowable material in the form of a body of revolution 3 from, which rests on the pipe jacket at the points not occupied by the coil and one has an inner diameter 4 that is dependent on the amount of material introduced. As a result the centrifugal force penetrates the flowable material into all open spaces of the coil, so that by the rotational body 3 formed both the gaps between the coil turns as well as the entire coil embedded in the material are. As soon as the desired final state is reached, the supply of flowable Material finished. Continuing the rotation, the transfer of the flowable material through polymerization into the solid state. The rotation can be terminated when the supplied material is dimensionally stable has reached. The polymerization itself ka. nn z. 13. by appropriate heating of the material including the casting mold can be achieved or the inaccessible material already contain catalytes, or a gas atmosphere can be introduced into the casting mold which favors the polymerization.

After finishing the rotation, the finished item becomes that is in the present case the embedded and filled coil, removed from the mold.

In the embodiment according to FIG. 2, the same mold is again used 1 is used with the axis of rotation 4, in which again an electrical coil 2 is used, which prevents movement and rotation relative to the mold Appropriate funds are secured. In contrast to the embodiment according to FIG however, the coil is to be embedded in a synthetic resin hollow cylinder on its outside whereas the inside should remain free. To enable the embedding on the To bring about the side of the coil 5 facing away from the axis of rotation, the coil is in one arranged such a distance from the mold wall that its surface with the the latter one through art Resin to be filled space of predetermined material. andstarklie forms. Will now flowable material) into the mold during the rotation of the same introduced, then this forms a body of revolution under the influence of centrifugal force 6, which is dimensioned according to the amount of material imported. that his free surface facing the axis of rotation is flush with the inside of the coil concludes, the flowable material penetrates again into all the spaces between the Coil, so that the coil is filled pore-free as well as in the material, as predetermined, is embedded. After experience during the rotation of the material in the solid state, the formed object can be in the form of the filled and embedded coil are removed from the mold.

In the embodiment according to FIG. 3, it is again tubular Casting mold 1 used with a horizontal axis of rotation. There is a wire spool in this again 5 in the position explained in FIG. 2 relative to the casting mold wall relative to the latter used immovably. In addition, however, is at a distance within the same another wire winding 7 is arranged. Both components 5 and 7 are to be embedded in this way that the inner free boundary surface of the embedding body is flush with the inside of the wire winding 7 completes. The wire winding 7 is also through suitable measures against relative displacement and rotation with respect to the casting mold secured. It is now inaccessible embedding material during the rotation required amount introduced. Forms under the influence of centrifugal force a body of revolution 8 of the predetermined shape and extent, all of which are open Fills spaces, so both the space between the pipe wall and the coil 5 as also those between the latter and the wire winding 7, as well as all the spaces and pores within the two components 5 and 7. After transferring the filled Material in the solid state stops rotating and the formed object taken from the mold. The latter may or may not have already hardened after it has completely hardened after reaching the dimensional stability of the material. Complete curing can happen in a subsequent process, be it not for the centrifugal form to take a long time, be it to make the embedding material easy to bind for a to obtain another resin layer to be applied.

In the embodiment according to FIG. 4, a casting mold is again used Tube 1 is provided with a horizontal axis of rotation A-A. Two wire windings are to be embedded 9 and 10, such that there is a free space between the two wire windings. The wire windings 9 and 10 are therefore in a free space corresponding to this Distance from one another, otherwise inserted concentrically to one another in the tube 1 and secured relative to this against turning and shifting. It will now be in three Levels worked. In the first stage, as in the exemplary embodiment according to FIG. 2 explains a body of revolution 6 produced, flowable material being the desired Texture and predetermined length is used. After transferring to the solid However, state becomes a flowable material of others without interrupting rotation Quality, which is filled into the mold, in such an amount that the hollow cylindrical space 11 is filled, the wall thickness of which corresponds to Distance between the two windings 9 and 10 corresponds.

This material is also converted into the solid state and in the solid state has a quality that can be subsequently removed again suitable. It can e.g. B. a material with a low melting point, such as. B. a wax, be used. After completing the second stage of the procedure, there will be no interruption of the rotation process in the third stage liquid, for embedding the winding 10 certain material introduced and here, as in principle with reference to FIG. 1 described. a body of revolution 3 is produced. After transfer to the solid state the rotation is now stopped and after removing the object from the mold the in the hollow cylinder space 11 handy material z. B. removed by melting out. This then results in two wire windings embedded in the predetermined manner coordinated dimensions.

The embodiment according to FIG. 5 is a condenser bushing to manufacture. A pipe 1 with a horizontal axis of rotation is again used as the casting mold A-A used. For the time being, the outer capacitor electrode2 is inserted into this tube, the outside diameter of which corresponds to the inside diameter of the pipe 1. The component 12 is again secured against relative displacement and rotation with respect to the tube 1. Then, with the mold rotating, flowable material is used to form the hollow cylindrical Synthetic resin layer 13 introduced, which embeds the electrode 12. After transfer of the filled material in the solid state, the first process stage is completed. It is now on the free surface formed of the hollow body 13 z. B. by brushing a Rondensatorhelag 14 applied with graphite. Then the form returns to Rotation set and by introducing suitable flowable material of the rotary hollow body 15 formed. which embeds the capacitor plate 14. It is expedient to solidify of the previously formed hollow body 13 to advance only as far as to achieve dimensional stability is absolutely necessary. so that the one in the second Process stage connects filled hollow bodies 15 with the first-mentioned properly, what z. B. is the case when the hollow body 13, which is made of synthetic resin iic still is not largely fully polymerized. iitili now after appropriate consolidation of the hollow body 15, the next capacitor plate 16 on the free surface of the Hollow body 15 applied and then in a further process stage of the rotary body 17 formed, etc. After the end of the last stage of the process, the rotation is terminated and the formed object is out of the mold, is by the explained subdivision of the procedure into several stages under interim successive introduction of components in the form of the capacitor layers the complete A saving of the latter in a coherent synthetic resin body has been made possible.

In the embodiment according to FIG. 6, it is the production a high voltage coil.

A casting mold is used, which consists of a tube 18 with a horizontal Axis of rotation A-A consists. which with two outwardly directed cup-shaped Approaches 19 is equipped. whose cavity merges directly into the tube cavity. To achieve a mass balance, you can, as on the opposite side in Fig. 6 is indicated in broken lines. corresponding counter-approaches 19 'are the same Shape can be provided in the same way with their cavities in the tube cavity pass over so that a symmetrical centrifugal body is formed.

The high voltage winding 20 of the coil is now inserted into the mold and in the predetermined position against shifting and rotating relative to the mold secured. The coil 20 is connected to power connection lines 21 and 22 at both ends connected. which passed through the lugs 19 centrally and radially to the coil axis are. The coil axis coincides with the axis of rotation A-A. The power supply lines are passed through suitable bores in the lugs 19.

The mold is now rotated and it becomes flowable Material supplied in the predetermined quality and in a menu that is sufficient to embed both the coil 20 and leads 21 and 22 as well as the Fill cavities in the approaches 19 and, if necessary, 19 '. Then the Conversion of the flowable material into the solid state. Then the The rotation is ended and the mold formed in two parts is dismantled exposed the formed object. If approaches 19 'have been used, then the relevant material parts formed in these are subsequently cut away, since they were only created as process aids. a perfect one To achieve balancing of the rotating parts.

The embodiment according to FIG. 7 is about manufacture a high voltage transformer with an open iron core. It will be a cup-shaped one Casting mold 23 is used, which has a vertical axis of rotation A-A and after is closed at the bottom by a spherical, dish-shaped bottom 24. In the mold 23, a high-voltage winding 25 is inserted along the cylindrical wall, which fits snugly against the wall of the cup. Before inserting further components Now the mold with the one opposite it secured against shifting and turning High voltage winding set in rotation. Then material from above becomes inaccessible introduced with a predetermined quality and quantity. As a result of centrifugal force the material becomes outward and, due to the shape closed at the bottom, downward driven, whereby v. due to the simultaneous influence of gravity a Free boundary surface 26 forms, which is one from below in the cylindrical mold part upward to a certain extent continuously increasing radial distance from the axis of rotation.

The flowable material therefore takes a shape in the direction of the Axis downwards increasing wall thickness. in which the high voltage winding 25 is embedded filling all spaces and pores. At the bottom part 24 The wall thickness of the casting mold is greatest. The entire free boundary area has a cup-shaped (paraboloidal) shape. The rotation continues until the flowable material in the solid state, e.g. B. by polymerization in a synthetic resin, has been convicted. The material now forms the insulating body 27, which in the axial direction from top to bottom has an increasing insulation resistance. how he the voltage curve of the high voltage winding in terms of the formation of a consistent insulation strength is adapted in the sense. The educated object is now removed from the mold after rotation has stopped. Then will the outer surface 28 located below the winding 25 of the insulator covered with a conductive layer, as well as the inner surface26 of the insulating body.

An iron core 29, which carries a low-voltage winding 30, is now inserted into the insulator, which basically completes the transformer is. However, this is in the position shown in Fig. 7 opposite the position of use on the head.

The embodiment according to FIG. 8 is about manufacture a post insulator. A casting mold31, closed at the bottom and cup-shaped on the inside, is produced with vertical axis of rotation A-A used. In the mold 31 is a screw the busbar certain head fitting 32, centered on the axis of rotation on the Sitting on the ground, inserted. Now flowable material is used in the formation the required quality and quantity of the insulation body is filled into the mold and then on the top of the mold one of the top pivot pins 33 for the mold 31 having foot fitting 34 placed centrically to the axis of rotation. The shape 31 together with the fittings 32 and 34 is then set in rotation. Under the influence centrifugal force and gravity take the poured flowable material the shape 35, in which the two fittings 32 and 34 are embedded. the Rotation continues until the flowable material is solidified has been. The material now forms the insulating body of the shape 35, which after Removal from the mold and after turning through 180 ° in the position of use below the Foot armature 34 and above the head armature 32 carries.

PATENT CLAIM: 1. Application of the method for manufacturing bodies made from polymerisation hardening, solvent-free synthetic resins with embedded, Metal parts of any shape by centrifugal force in a mold, whereby the synthetic resins harden in the mold, for embedding electrotechnical, in particular high-voltage technical apparatus and devices and parts thereof using a low-pressure resin that cures without splitting off volatile constituents as synthetic resin.

Claims (1)

2. Application of the method according to claim 1, characterized in that is spun in several process stages and the parts to be embedded, z. B. wire spools, iron cores and the like., Can only be used before the relevant stage. 3. Application of the method according to claim 1, characterized in that for arranging conductive capacitor inserts the shaped body initially up to the for they prepared place, then the deposits z. B. by painting applied to an electrically conductive mass and then optionally with further resin raw material applied by centrifugation. 4. Process application according to Claims 1 to 3, characterized in that that the starting material in a cylindrical or slightly conical inner surface having, closed at the bottom Cup-like casting mold with a vertical axis of rotation centrifuged at such a speed and a predetermined amount of the flowable substance becomes that the resin body subsequently solidified during rotation is one of its bottom part has gradually weakening wall thickness up to the mouth, the electrotechnical parts before the centrifuge or before the implementation of the corresponding process stage are fixed in the mold. 5. Method application according to claim 1 or one of the following claims, characterized in that to produce an embedding with in a certain layer or in certain layers of different properties (e.g. with regard to the dielectric constant) the resin source materials, preferably solid materials, of different properties are added, their specific weights, if necessary also quantities related to the specific gravity of the liquid resin raw material or are graded against each other in such a way that the added substances are spun into the one for the relevant shift or Layers and move here together with the for the embedding compound used insulating resin the layer in question or Layers of different nature (e.g. with regard to the Dielectric constant). 6. Process application according to Claims 1 to 5, characterized in that that the spinning takes place in several process stages and that after the end of the the entire process from the material assigned to at least one process stage its space is removed again, whereby the material to be removed has properties which allow removal without damaging the remaining synthetic resin material, z. B. lower melting point if removal is done by melting out, or solubility in relation to certain substances when removing by leaching out he follows. 7. Process application according to Claims 1 to 6, characterized in that that the spaces not to be filled with material are blocked by packing against material access to be protected. 8. Application of the method according to claim 7, characterized in that not to be connected to each other by the material, used in the same mold Objects are separated from each other by spacers, which at least at the areas that come into contact with the flowable material cause adhesion of the flowable material have an obstructive surface quality. Considered publications: German Patent Specifications No. 717188, 728957; Swiss Patent No. 226 983; French patents No. 951 172, 977349; "Excerpts from German patent applications", Vol. IV, Electrical engineering, Class 21 g, p. 588 (S 149750 VIII c / 21g). Older patents considered: German Patent No. 910 919.