CA1051986A - Synthetic resin packed coil assembly - Google Patents
Synthetic resin packed coil assemblyInfo
- Publication number
- CA1051986A CA1051986A CA235,888A CA235888A CA1051986A CA 1051986 A CA1051986 A CA 1051986A CA 235888 A CA235888 A CA 235888A CA 1051986 A CA1051986 A CA 1051986A
- Authority
- CA
- Canada
- Prior art keywords
- synthetic resin
- layer
- turns
- high strength
- assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F5/00—Coils
- H01F5/06—Insulation of windings
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Insulating Of Coils (AREA)
- Insulation, Fastening Of Motor, Generator Windings (AREA)
- Manufacture Of Motors, Generators (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A synthetic resin packed coil assembly is described comprising a wound spiral of a number of bundled turns of insulated wire surrounded by an outer insulating layer. This insulating layer is composed of a synthetic resin reinforced by a high strength fibrous material and is formed by first winding the high strength fibrous material around the bundled turns of insulated wire of the wound spiral, subsequently impregnating this with a solution of the synthetic resin and finally allowing the synthetic resin to harden.
A synthetic resin packed coil assembly is described comprising a wound spiral of a number of bundled turns of insulated wire surrounded by an outer insulating layer. This insulating layer is composed of a synthetic resin reinforced by a high strength fibrous material and is formed by first winding the high strength fibrous material around the bundled turns of insulated wire of the wound spiral, subsequently impregnating this with a solution of the synthetic resin and finally allowing the synthetic resin to harden.
Description
~o5~9~6 The present invention relates to a synthetic resin packed coil assembly for use in an electric circuit.
The accompanying drawings illustrate both the prior art and the present invention as follows:
Fig. 1 is a per:;pective view of the prior art coil assembly;
Fig. 2 is a cross sectional view, on an enlarged scale, taken along the line II-II in Fig. 1, reference to Figs. 1 and 2 having already been made in the foregoing description;
Figs. 3 to 5 illustrate various method of wind-ing a thread of high strength fihrous material around a wound spiral of turns of electrical insulated wire, wherein Fig. 3 is a similar view to Fig. 1 showing the thread of high strength fibrous material being wound to form sub-stantially parallel turns thereof, Fig. 4 is a perspec~ive view of a portion of the coil assembly showing the thread -Jo~ dd '~ of high strength fibrous material being ~euld to form .
substantially crosseà turns and Fig. 5 is a view similar to Fig. 4 showing a tape of high strength fibrous material being wound to form substantially overlapping turns;
Fig. 6 is a view similar to Fig. 2, showing a cross sectional representation of the coil assembly accord-ing to the present invention;
Fig. 7 is a cross sectional view of a portion of Fig~ 6 shown on an enlarged scale, showing the formation of a multi-layer of synthetic resin;
Figs. 8 and 9 illustrate different methods of making a coil assembly according to the present invention;
and Figs. 10 to 14 illustrate cross sectional repre--- 1 -- .
1051986sentations of various coil assemblies according to the present invention.
A synthetic resin packed coil assembly to which the present invention pertains is not itself novel. As shown in Fiys. 1 and 2 of the accompanying drawings which are respectively a perspective view of a prior art coil assembly of a similar kind and a cross sectional view there-of ta~en along the line II-II in Fig. 1, the prior art coil assembly comprises a wound spiral 1 having a plurality of turns 2 of insulated wire, made of electric conductive material such as copper, iron or aluminum, having the opposite ends formed into leads 4 or external electric connection, which wire turns 2 represent, as best shown in Fig. 2, a bundled configuration in section. The wire turns
The accompanying drawings illustrate both the prior art and the present invention as follows:
Fig. 1 is a per:;pective view of the prior art coil assembly;
Fig. 2 is a cross sectional view, on an enlarged scale, taken along the line II-II in Fig. 1, reference to Figs. 1 and 2 having already been made in the foregoing description;
Figs. 3 to 5 illustrate various method of wind-ing a thread of high strength fihrous material around a wound spiral of turns of electrical insulated wire, wherein Fig. 3 is a similar view to Fig. 1 showing the thread of high strength fibrous material being wound to form sub-stantially parallel turns thereof, Fig. 4 is a perspec~ive view of a portion of the coil assembly showing the thread -Jo~ dd '~ of high strength fibrous material being ~euld to form .
substantially crosseà turns and Fig. 5 is a view similar to Fig. 4 showing a tape of high strength fibrous material being wound to form substantially overlapping turns;
Fig. 6 is a view similar to Fig. 2, showing a cross sectional representation of the coil assembly accord-ing to the present invention;
Fig. 7 is a cross sectional view of a portion of Fig~ 6 shown on an enlarged scale, showing the formation of a multi-layer of synthetic resin;
Figs. 8 and 9 illustrate different methods of making a coil assembly according to the present invention;
and Figs. 10 to 14 illustrate cross sectional repre--- 1 -- .
1051986sentations of various coil assemblies according to the present invention.
A synthetic resin packed coil assembly to which the present invention pertains is not itself novel. As shown in Fiys. 1 and 2 of the accompanying drawings which are respectively a perspective view of a prior art coil assembly of a similar kind and a cross sectional view there-of ta~en along the line II-II in Fig. 1, the prior art coil assembly comprises a wound spiral 1 having a plurality of turns 2 of insulated wire, made of electric conductive material such as copper, iron or aluminum, having the opposite ends formed into leads 4 or external electric connection, which wire turns 2 represent, as best shown in Fig. 2, a bundled configuration in section. The wire turns
2 of the spiral wound 1 are externally covered with a layer of synthetic resin 3 of electrically insulating property by means of an injection molding technique or a plastic die casting technique.
However, it has been found that, during the use of the prior art coil assembly of the above construction in an external electric circuit, internal stress set-up occurs in the resin layer 3 due to the difference in thermal expansion coefficient between the synthetic resin for the layer 3 and ~aterial for the wire of the wound spiral 1 and,~therefore, in most cases, the internal stress set-up results in formation of cracks in the resin layer 3 which leads to a substantial malfunction of the coil assembly or otherwise insufficient performance of the same.
This drawback may be removed by employing a synthetic resin for the layer 3 which contains a relatively large amount of inorganic powdery filler which is added l~)S19t~
thereto in ordcr for the thermal expansion coefficient of the resin layer 3 to be equalized, or approximated to that of the electric wire of the wound spiral 1. Although this may result in relief of the internal stresses which may otherwise be set up in the layer 3 by the difference in thermal expansion coefficient, the physical strength of the layer 3 is adversely affected to an extent that the resul-tant coil assembly can no longer withstand against a re-latively high electric load. Moreover, the use of the synthetic resin,to which the inorganic powdery filler has been added, for the layer 3 does not completely remove a possibility of formation of cracks in the layer 3 and, therefore, the resultant coil assembly is liable to a~-substantial malfunction or, otherwise, reduction in per-formance.
Considering a manufacturing process, the addition of the inorganic powdery filler to the synthetic resin for the layer 3 causes an increase of the viscosity of such synthetic resin in molten state and, therefore, impregna-tion and injection-molding with the wound spiral 1 requires a relatively long time. Moreover, during the impregnation, voids tend to develop and the resultant layer 3 will not exhibit a desired or required electric property.
In general, the respective thermal expansion coefficients of the electric wire for the spiral 1 and the synthetic resin or the layer 3 may be substantially equal to each other if the temperature evolved in the coil assembly during the use in an external electric circuit is lower than the heat distortion temperature of the synthetic resin for the layer 3, that is, the temperature at which heat distortion takes place in the layer 3. However, where 10519~
the tcmprrature evolved in the coll assembly is lligher than the heat distortion temperature, the thermal expanslon coefficient of the synthetic resin for the layer 3 increases on one hand and the thermal expansion coefficient of the electric wire for the wound spiral 1 substantially remain the same and, therefore, the diffe ence in thermal expanslon coefficient results in a considerable stress set-up in the layer 3 Because of the above reason, the prior art coil assembly lacks a sufficient resistance to cracking with a consequent reduction in temperature resistance.
Accordingly, the present invention has for its essential ob~ect to provide an improved synthetic resin packed coil assembly, wllich substantially eliminates many of the drawbacks inherent in the prior art coil assemblies of a similar kind.
In accordance with the present invention, there is provided a synthetic resin packed coil assembly which is impreg-nated at the outer periphery thereof with synthetic resin layer including therein a high strength fibrous material, said coil assembly comprising; a wound sprial of a plurality of bundled turns of insulated wire, an intermediate insulating layer formed between said wound spiral and said synthetic resin layer including the high strength fiber material and, a semi-conductive layer further formed between said intermediate insulating layer and said synthetic resin layer, said semi-conductive layer being constituted by a first ply integrally formed with said intermediate insulating layer and also a second ply integrally formed with said synthetic resin layer including the high strength fibrous material, with an air gap layer being further formed between said first and second plies over the entire peripheral surface for preventing chemical adhesion between said intermediate insulating laycr and synthetic resin layer.
An advantage of the present invention, at least in 105198~;
preferred ~orms, ls tilat it can provide an improved synthetic resin packed coil assembly, which is not liable to crack formation even when subjected to severe conditions or electric loads.
A further advantage of the present inventiOn, at least in preferred for~s, is that it can provide an improved synthetic resin packed coil assembly, which exhibits good electrical pro-perties and a relatively high temperature resistance and which is accordingly relia~le in performance.
Before the description of the present invention proceeds, it should be noted that like parts are designated by like reference numerals throughout the accompanying drawings.
Referring first to Figs. 3 to S, reference numeral 5 represents a wound spiral having a plurality of turns of insulated wire. Reference numeral 6 represents a wound high strength fibrous material such as a glass roving.
The high strength fibrous material may be toroidally wound àround the bundled turns 2 of the wound spiral 5 to form substantially parallel turns such as shown in Fig. 3, or may be wound around the bundled turns 2 of the wound spiral 5 to form substantially crossing turns such as shown in Fig. 4. The high strength fibrous material may be employed in the form of a continuous tape, in which case the tape of the high strength fibrous material 6 is wound around the bundled turns of the wound spiral 5 to form substantially overlapping turns such as shown in Fig. 5~ In practice, a combination of the methods of Figs. 3 and 4, or of Figs. 3 and 5, or of Figs. 4 and 5, or of all of Figs. 3 eo 5 can be employed. Alternatively, turns of the high strength fibrous material 6 may extend in parallel relation to the direction ~;
of turns of the electric wire forming the wound spiral 5 singly or together with such ~,~
lOSl9~t;
turns of the high strength fibrous material 6 may not ~e always limited to that shown in any of Figs. 3 to 5, but may be selected as desired.
Where the winding of the high strength fibrous material 6 is not desired, it may be arranged around the outermost bundled turns 2 of the wire forming the wound spiral 5 so as to cause fibers of the material 6 to en-tan~le to each other. Even in this case, no reduction in performance of the resultant coil assembly according to the present invention will be appreciated.
The high strength fibrous material 6 may be selected from the group consisting of glass, carbon, boron, silica, alumina and "~evlar" (Trade Mark of Du Pont).
The shape of the high strength fibrous material 6 may be in the form of a roving, such as shown in any of Figs. 3 and 4, a tape such as shown in Fig. 5, a cloth, a non-woven cloth, a mat or the like.
The wound spiral having the bundled turns 2 around which the high strength fibrous material 6 has been 2D provided is impregnated with synthetic resin under sub- -~tantially vacuum atmosphere so as to allow the synthetic resin to penetrate into interstices among the bundled turns 2,of the wire. At the time the impregnated synthetic resin has been hardened, a layer of the synthetic resin reinforced by the high strength fibrous material so uni--formly enveloped in such synthetic resin is formed around the outermost bundled turns 2 of the wire forming the wound spiral 5 with no void formed therein.
Alternatively, in order to form the electrically 10519~
insulating layer of synthetic resin referred to above, any of methods, such as shown in Figs. 8 and 9, respec-tively, may be employed wherein a synthetic resin, which has not yet be hardened, is first applied to the high strength fibrous material, the latter being subsequently wound around the outermost bundled turns of the wire of the wound spiral 1 and, finally, the synthetic resin which has been applied to the high strength fibrous material is allowed to harden. It will readily be seen that, because of the presence of the high strength fibrous material, the synthetic resin upon having been hardened is rein-forced thereby to provide the insulating layer. The syn-*hetic resin used in the practice of any of the methods of Figs. 8 and 9 may, or may not; contain a filler material.
Referring ncw to Fig. 8, prior to the high strength fibrous material 6 being wound around the bundled turns of insulated wire forming the spiral 5, the high strength fibrous material 6 is continuously immersed in a solution of synthetic resin, accommodated in a container 12, to apply the synthetic resin 13 to the high strength fibrous material 6. At the time the high strength fibous material 6 is wound around the bundled turns of insulated wire forming the wound spiral 5, the high strength fibrous material 6 is held under a predetermined tension to allow excessive synthetic resin and voids contained in the synthetic resin 13 to be removed. According to this method of Fig. 8, the high density insulating layer 8 of synthetic resin can be formed around the bundled turns of wire forming the wound spiral 5.
In the method shown in Fig. 9, at the time of winding of the high strerlgth fibrous material 6 around the bundled turns of wire of the wound spiral 5, the high strength fibrous material 6 is fed through a pair of jux-s taposed rolls 14. One of the juxtaposed rolls 14 which is rotatably supported above the other is positioned below a nozzle at the bottom of a container 12 for a solution of synthetic resin so that the latter can be supplied onto the upper roll 14 through the nozzle 16. In this arrange-ment, it will readily be understood that the solution of synthetic resin is applied to the high strength fibrous material 6 through the rolls 14. By adequately adjusting the clamping force exerted by the juxtaposed rolls 14 on the high strength fibrous material 6 passing therethrough, the high strength fibrous material 6 can be moved under a predetermined tension and subsequently wound around the bundled turns of wire of the wound spiral 5 to form the high density insulating layer 8 of synthetic resin. In a substantially similar manner to the method of Fig. 8, be-cause of the tension imparted on the high strength fibrous material 6 during the winding operation, excessive resin and voi`ds contained in the synthetic resin applied to the high str~ngth fibrous material 6 can advantageously be removed.
However, complete removal of the voids which may otherwise be left in the insulating layer 8 would be dif-ficult without, for example, the tension of the high strength iibrous material 6 being adequately controlled. In such a case it is recommended to carry ou. the winding operation .
105~91~f~
of the hiyh strcngth fibrous material 6 to which the Syh-thetic resin has already been applied, under a su~stantially vacuum atmosphere to ensure a complete removal of the voids.
Other methods of winding the high strength fibrous material having a solution of synthetic resin applied there~
to can be contemplated. One of the methods that can be contemplated is that the synthetic resin is applied to the high strength ~ibrous material by fusing by the application of heat a synthetic resin which is solid under ambient temperature and subsequently allowing it to harden after the high strength fibrous material with the synthetic resin applied thereto has been wound around the bundled turns of wire of the wound spiral 5. Another one of the methods that can be contemplated is that the synthetic resin, after having mixed with a hardening agent, is applied to the high strength fibrous material 6 and is subsequently allowed ` to assume a substantially semi-cured or semi-hardened state.
A cross sectional representation of the bundled turns of wire of the wound spiral S forming the resin packed coil assembly according to the present invention is shown in Fig. 6 wherein reference numeral 7 represents the bundled turns of wire of the wound spiral S and reference numeral 8 represents the insulàting layer 8 formed in the manner as .~ hereinbefore described.
In Fig. 7, the insulating layer 8 is depicted as composed of a plurality of, for example, three plies.
According to the present invention, since the insulating layer 8 is composed of the synthetic resin, hav-ing a thermal expansion coef$icient greater than that of g _ .
~OSlg8~
the wire of the wound spiral S, and the high strength fibrous material, such as glass, having a thermal expansion coefficient smaller than the wire of the wound spiral 5, the thermal expansion coefficient of the resultant insu-lating layer 8 can be rendered substantially equal to orapproximating to that of the wire of the wound spiral 5.
Although, during the use of the coil assembly in the external circuit, stress set-up may take place in the insulating layer 8 if there is a difference in thermal expansion coefficient, the insulating layer 8 composed of the synthetic resin reinforced by the high strength fibrous material exhibits a highly improved physical strength, even when subjected not only to a relatively low temperature and an ambient temperature, but also to a higher temperature than the heat destortion temperature of the synthetic resin used, an~, therefore, no substantial crack occur in the insulat-ing layer 8. By way of example, where glass rovings and epoxy resin are respectively employed for the high strength fibrous material 6 and the synthetic resin which is applied to the fibrous material 6, the physical strength of the resultant insulating layer 8 is about 5 times at an ambient or room temperature and about 15 times at 150 to 200~C. with respect to the physical strength exhibited by an insulating layer which is prepared solely from the epoxy resin with no high strength fibrous material added.
Furthermore, according to the present invention, since the insulating layer 8 of the sufficiently high physical strength as described above can be obtained in the construction of the coil assembly shown in any of Flgs. 6 1051~386 and 7, the concept of the present invention can be appli-cable in manufacturing a highly reliable coil assembly which can satisfactorily be operated in a highly power-loaded external circuit, which has a relatively high tem-perature resistance and which is compact in size accordingly.
In addition to the foregoing features, since thesynthetic resin of low viscosity can be employed during the manufacture of the coil assembly according to the present invention, the required time to carry out the impregnation process can advantageously be shortened with no substantial flaws, such as resulting from the presence of voids, appear-ing in the resultant,coil assembly.
According to eith~r of the methods wherein the high strength fibrous material, after having been wound around the bundled turns 7 of wire of the spiral 5, is im-pregnated with synthetic resin or wherein the high strength fibrous material, after having applied with a solution of synthetic resin, is wound around the bundled turns 7 of wire of the spiral 5, the insulating layer 8 wherein the high strength fibrous material is present in an entangled form of long fibers and is uniformly distributed can be easily be obtained completely around the bundled turns 7 of wire,of the wound spiral 5.
As hereinbefore described, the coil assembly of the construction shown in Fig. 6 is excellent in performance.
However, during the manufacture thereof, it has been found that there is a possibility that the bundled turns 7 of wire of the wound spiral 5 are not completely bonded to the insulating layer 8 of synthetic resin reinforced by--: .:. . .. ,:, , ~:;. .
10519~36 by the high strength fibrous material and that an electrically insulating layer solely composed of the synthetic resin is consequently formed between the bundled turns 7 and the in-sulatin~ layer 8. This is particularly true where the bundled turns 7 of wire of the wound spiral 5 represents a rectangular or square cross section and, since the high strength fibrous material insufficiently fills up the inter-stices among the bundled turns of wire of the wound spiral 5 if the wire has a circular cross sectional shape, only the synthetic resin is present penetrated into the inter-stices thereby forming an electrically insulating layer.
On the other hand, while the thermal expansion coefficient of the electric wire prepared from aluminum and that of the electric wire prepared from copper are respectively about 2.2 x 10 5 and 1.6 x 10 5 cm/cm/C., the thermal expansion coefficient of, for example,tepoxy resin, is 5 x 10 5 cm/cm/C. at room temperature and 5 x 10 4 cm/cm/C. at 150 to 200C. Accordingly, if the layer of only the synthetic resin is formed in the manner as hereinbefore described, considerable stresses will be set up in such resin layer as the temperature increases during the use of the coil assembly, which stresses are liable to formation of cracks. Oncè these cracks occur in the resin layer, corona discharge occur at portions of the resin layer where the cracks are fcrmed upon applica-tion of a relatively high voltage to the coil assembly and, therefore, the durability of the coil assembly is reduced.
The foregoing problem can ~e advantaseously ~ .
105~6 solved according to any of embodiments of the p~esent in-vention shown in Figs. 10 and 11, respectively.
With particular reference to Fig. 10, hetween the insulating layer 8 of synthetic resin reinforced by the high strength fibrous material and the bundled turns 7 of wire of the wound spiral 5, there is formed an inter-mediate insulating layer 9 having a relatively low thermal expansion coefficient, for example, approximate to the thermal expansion coefficient of the electric wire used to form the wound spiral 5. According to a series of experimentsconducted, it has been found that the interme-diate layer 9 is preferred to have a thermal expansion coefficient of not more than 4 x 10-5 cm/cm/C.
Material for the intermediate insulating layer 9 may be a synthetic resin admixed with an inorganic insu-lating substance or a filler of such inorganic material as silica, alumina, hydrated alumina, calci.um carbonate, magnesia, talc, clay, tinanium oxide, mica, glass and so on.
The synthetic resin admixed with the inorganic insulating material or the inorganic material as the filler cannot be satisfactorily used to form an outermost covering for the bundled turns of wire of the wound spiral. However, in the present invention, since the synthetic resin admixed with the inorganic insulating material or the inorganic material as the filler is used as a material for the inter- -;
mediate insulating layer 9 disposed between the bundled turns 7 of wire of the wound spiral 5 and the insulating layer 8, the layer 9 may have a relatively small thickness.
This is possible because the insulating layer 8 acts as a .. .
~. ' -primary insulator and, concurrently, the outermost protec-tive covering.
In view of the thickness of the intermediate layer 9 being small, the intermediate insulating layer 9 is so deformable following the stresses set up therein, so low in thermal expansion coefficient and so less liable to formation of cracks that the highly reliable coil assembly can be manufactured according to the present invention.
As a method for forming the intermediate insulat-ing layer 9, any known fluidized bed technique, electro-static fluidized bed technique, spray technique or electro-static spray technique can be employed. In the practice of any of these known techniques, the resin admixed with the inorganic insulating material or the inorganic material as the filler is applied in the form of a powder and, accordingly, the intermediate insulating layer 9 of uni-formly small thickness can readily be formed around the bundled turns 7 of wire of the wound spiral 5. Preferablv, the synthetic resin material for the layer 9 contains the inorganic material as the filler as hereinbefore described.
The synthetic resin material for the layer 9 may be epoxy resin, p~lyester resin or the like and manufacture of the coil assembly according to the pre~ent invention wherein the intermediate layer 9 is prepared from the synthetic resin with the inorganic insulating material contained therein or with the inorganic material contained therein as the filler can automatically carried out.with no substan-tially complicated procedures involved.
The intermediate insulating layer 9, even though ~05~986 it is a layer of relatively small thickness, having a suf-ficiently high physical strénqth and being so deformable as to follow the internal stresses, is less liable to formation of cracks therein. Accordingly, even in the coil assembly of the construction shown in Fig. 10, the above described advantages can be appreciated. By way of example, according to a series of experimentsconducted, it has been found that the synthetic resin material of not less than 8 kg/mm2 in bending strength and not less than 5% in elongation is more suited as a material for the intermediate insulating layer 9. Examples of the synthetic resin material for the insulating layer 9 may include a compound with metallic material and rubber or rubber-like material.
If as a material for the intermediate insulating layer 9 a porous material- is employed, the synthetic resin can, during the impregnation process, penetrate into the pores of the material forming the layer 9 to fill the pores and, therefore, the level at which corona dis-charge takes place and the impulse surge in the resultant coil assem~ly can advantageously be improved. It is to be noted that the synthetic resin which has penetrated into the pores of the material forming the intermediate layer 9 is subsequently hardened and, therefore, if such a porous material which, when hardened, exhibits a rela-tively low thermal expansion coefficient, has a relatively high physical strength or has a relatively high elongation, the layer 9 composed of such synthetic material can serve as an insulator.
' 1o5~986 - On the other hand, if the intermediate layer 9 can exhibit a property similar to a semi-conductor having an appropriate resistance, no substantial potential diffe-rence will be created in the layer 9 even if the latter has voids and/or cracks therein, and corona discharge will hardly occur. In the embodiment shown in Fig. 12, while the intermediate layer 9 serves as an insulator, a semi-conductive or conductive layer 10 is formed between the layer 9 and the layer 8 composed of the synthetic resin reinforced by the high strength fibrous material as herein-before described. In this construction as shown in Fig. 12, since the semi-conductive layer 10 does not directly con-tact the outermost turns of the bundled turns 7 of wire of the wound spiral 5, not only the leakage potential level at the outermost turns of the bundled turns 7 can advantageously be minimized, but also an effect of relief of the electric field of the semi-conductive layer 10 can be expected as hereinbefore described.
In the embodiment shown in Fig. 13, the semi-2~ conductive or conductive layer 10 is compo~ed of inner and outer semi-conductive or conductive plies 10a and 10b with a gap 11 located between the outer and inner plies lQb and 10a. Material for the inner and outer plies 10a and 10b and, therefore, the layer 10, may be any con-ductive material, such as carbon, a sheet containing carbon,a metallic compound or a metal, or synthetic resin.
During the operation of the coil assembly of the con-struction shown in Fig. 13, since the potential of either of the inner and outer plies 10a and 5198~
lOb is substantially equalized to that of the other of the inner and outer plies lOa and lOb over the outermost turns of the bundled turns 7 of wire of the wound spiral 5, no potential differer.ce is substantially created in the gap 11 and, therefore, no corona discharge occurs. Ano-ther advantage resulting from the provision of the gap 11 is that the gap 11 absorbs variation in volume of any of the inner and outer plies lOa and lOb which may result from variation of the ambient temperature, vari-ation of the operating temperature of the coil assembly ;Y--and/or variation in dimension due to aging and that the internal stresses can, therefore, be relieved.
With the construction shown in Fig. 13, in addi-tion to the internal stress relief achieved in the manner as hereinbefore described, the effect of electric field relief can also be attained in a manner similar to the construction shown in Fig. 12.
Still referring to Fig. 13, the inner and outer plies lOa and lOb of the semi-conductive or conductive layer 10 are preferably firmly bonded to the intermediate layer 9 and the synthetic resin layer ~, respectively.
This can be achieved by applying a synthetic resin, such as a semi-conductive powdery synthetic resin, to the outer peripheral surface of the layer ~, subsequently applying, or otherwise, lining such a material having a parting property as silicon or tetrafluoroethylene over the applied synthetic resin, thereafter winding the high strength fibrous material after a semi-conductive material, such as a carhon sheet, has been wound around the applied synthetic ~-.
~051986 resin, and finally hardening the synthetic resin material after the assembly has been dipped in a solution of the synthetic resin material. The gap 11 herein referred to is not of a type having a uniform thickness between the inner and outer plies lOa and lOb and, in other words, is not chemically bonded to any of the inner and outer plies lOa and lOb. In practice, this gap 11 allows the inner and outer plies lOa and~lOb of the semi-conductive or conductive layer 10 to contact to each other at local positions and, accordingly, during the operation of the coil assembly, the plies lOa and lOb are charged the sub-stantially equal potential.
While the employment of the plies lOa and lOb are preferred, either the inner ply lOa or the outer ply lOb may be omitted if the gap 11 is sufficiently small`in thickness.
If in the construction shown in any of Figs. 12 and 13 the wire forming the bundled turns 7 of the wound spiral 5 is highly insulated or if the induced voltage between one layer and another of the coil assembly is sufficiently low, there may be provided the semi-conductive layer 10 between the bùndled turns 7 of wire of the wound spiral 5, and the layer 9 such as shown in Fig. 14. In this case, even if the insulated wire forming the bundled turns 7 of the wound spiral 5 does not exhibit a sufficient ~ `
bondability with~respect to the material of the layer which is held in contact therewith, the effect of electric field relief can be attained by the semi-conductive layer 10 between the bundled turns 7 and the layer 9.
The insulated wire employed to form the electro-magnetic coil assembly of any of the constructions shown in Figs. 3 to 14 is preferably employed in the form of a ~elf-fusible wire, that is, a wire sheathed with a thermo-plastic material. If this type of wire is employed and subsequently coiled to form the bundled turns 7, the bun-dled turns 7 can easily be obtained with one turn firmly bonding to adjacent turns upon application of heat thereto.
Therefore, any auxiliary elements, such as a temporarily binding tape, is not required to retain the shape of the bundled turns 7 of wire of the wound spiral 5 prior to the formation of the layer to be contacted to the outermost turns of the bundled turns 7 of wire of the wound spiral 5.
Furthermore, since an insulating sheet between the layers can be removed, the electromagnetic coil assembly, compact in size, can effectively and readily be manufactured at a high production rate.
Although the present invention has been fully described by way of the preferred embodiments thereof, it should be noted that various changes and modifications are ~`
apparent to those skilled in the art. Such changes and ;~
modifications, unless they depart from the true scope of the present invention, should be construed as included therein.
~ .:
,; , ~ ' .. .
' - -- 19 --
However, it has been found that, during the use of the prior art coil assembly of the above construction in an external electric circuit, internal stress set-up occurs in the resin layer 3 due to the difference in thermal expansion coefficient between the synthetic resin for the layer 3 and ~aterial for the wire of the wound spiral 1 and,~therefore, in most cases, the internal stress set-up results in formation of cracks in the resin layer 3 which leads to a substantial malfunction of the coil assembly or otherwise insufficient performance of the same.
This drawback may be removed by employing a synthetic resin for the layer 3 which contains a relatively large amount of inorganic powdery filler which is added l~)S19t~
thereto in ordcr for the thermal expansion coefficient of the resin layer 3 to be equalized, or approximated to that of the electric wire of the wound spiral 1. Although this may result in relief of the internal stresses which may otherwise be set up in the layer 3 by the difference in thermal expansion coefficient, the physical strength of the layer 3 is adversely affected to an extent that the resul-tant coil assembly can no longer withstand against a re-latively high electric load. Moreover, the use of the synthetic resin,to which the inorganic powdery filler has been added, for the layer 3 does not completely remove a possibility of formation of cracks in the layer 3 and, therefore, the resultant coil assembly is liable to a~-substantial malfunction or, otherwise, reduction in per-formance.
Considering a manufacturing process, the addition of the inorganic powdery filler to the synthetic resin for the layer 3 causes an increase of the viscosity of such synthetic resin in molten state and, therefore, impregna-tion and injection-molding with the wound spiral 1 requires a relatively long time. Moreover, during the impregnation, voids tend to develop and the resultant layer 3 will not exhibit a desired or required electric property.
In general, the respective thermal expansion coefficients of the electric wire for the spiral 1 and the synthetic resin or the layer 3 may be substantially equal to each other if the temperature evolved in the coil assembly during the use in an external electric circuit is lower than the heat distortion temperature of the synthetic resin for the layer 3, that is, the temperature at which heat distortion takes place in the layer 3. However, where 10519~
the tcmprrature evolved in the coll assembly is lligher than the heat distortion temperature, the thermal expanslon coefficient of the synthetic resin for the layer 3 increases on one hand and the thermal expansion coefficient of the electric wire for the wound spiral 1 substantially remain the same and, therefore, the diffe ence in thermal expanslon coefficient results in a considerable stress set-up in the layer 3 Because of the above reason, the prior art coil assembly lacks a sufficient resistance to cracking with a consequent reduction in temperature resistance.
Accordingly, the present invention has for its essential ob~ect to provide an improved synthetic resin packed coil assembly, wllich substantially eliminates many of the drawbacks inherent in the prior art coil assemblies of a similar kind.
In accordance with the present invention, there is provided a synthetic resin packed coil assembly which is impreg-nated at the outer periphery thereof with synthetic resin layer including therein a high strength fibrous material, said coil assembly comprising; a wound sprial of a plurality of bundled turns of insulated wire, an intermediate insulating layer formed between said wound spiral and said synthetic resin layer including the high strength fiber material and, a semi-conductive layer further formed between said intermediate insulating layer and said synthetic resin layer, said semi-conductive layer being constituted by a first ply integrally formed with said intermediate insulating layer and also a second ply integrally formed with said synthetic resin layer including the high strength fibrous material, with an air gap layer being further formed between said first and second plies over the entire peripheral surface for preventing chemical adhesion between said intermediate insulating laycr and synthetic resin layer.
An advantage of the present invention, at least in 105198~;
preferred ~orms, ls tilat it can provide an improved synthetic resin packed coil assembly, which is not liable to crack formation even when subjected to severe conditions or electric loads.
A further advantage of the present inventiOn, at least in preferred for~s, is that it can provide an improved synthetic resin packed coil assembly, which exhibits good electrical pro-perties and a relatively high temperature resistance and which is accordingly relia~le in performance.
Before the description of the present invention proceeds, it should be noted that like parts are designated by like reference numerals throughout the accompanying drawings.
Referring first to Figs. 3 to S, reference numeral 5 represents a wound spiral having a plurality of turns of insulated wire. Reference numeral 6 represents a wound high strength fibrous material such as a glass roving.
The high strength fibrous material may be toroidally wound àround the bundled turns 2 of the wound spiral 5 to form substantially parallel turns such as shown in Fig. 3, or may be wound around the bundled turns 2 of the wound spiral 5 to form substantially crossing turns such as shown in Fig. 4. The high strength fibrous material may be employed in the form of a continuous tape, in which case the tape of the high strength fibrous material 6 is wound around the bundled turns of the wound spiral 5 to form substantially overlapping turns such as shown in Fig. 5~ In practice, a combination of the methods of Figs. 3 and 4, or of Figs. 3 and 5, or of Figs. 4 and 5, or of all of Figs. 3 eo 5 can be employed. Alternatively, turns of the high strength fibrous material 6 may extend in parallel relation to the direction ~;
of turns of the electric wire forming the wound spiral 5 singly or together with such ~,~
lOSl9~t;
turns of the high strength fibrous material 6 may not ~e always limited to that shown in any of Figs. 3 to 5, but may be selected as desired.
Where the winding of the high strength fibrous material 6 is not desired, it may be arranged around the outermost bundled turns 2 of the wire forming the wound spiral 5 so as to cause fibers of the material 6 to en-tan~le to each other. Even in this case, no reduction in performance of the resultant coil assembly according to the present invention will be appreciated.
The high strength fibrous material 6 may be selected from the group consisting of glass, carbon, boron, silica, alumina and "~evlar" (Trade Mark of Du Pont).
The shape of the high strength fibrous material 6 may be in the form of a roving, such as shown in any of Figs. 3 and 4, a tape such as shown in Fig. 5, a cloth, a non-woven cloth, a mat or the like.
The wound spiral having the bundled turns 2 around which the high strength fibrous material 6 has been 2D provided is impregnated with synthetic resin under sub- -~tantially vacuum atmosphere so as to allow the synthetic resin to penetrate into interstices among the bundled turns 2,of the wire. At the time the impregnated synthetic resin has been hardened, a layer of the synthetic resin reinforced by the high strength fibrous material so uni--formly enveloped in such synthetic resin is formed around the outermost bundled turns 2 of the wire forming the wound spiral 5 with no void formed therein.
Alternatively, in order to form the electrically 10519~
insulating layer of synthetic resin referred to above, any of methods, such as shown in Figs. 8 and 9, respec-tively, may be employed wherein a synthetic resin, which has not yet be hardened, is first applied to the high strength fibrous material, the latter being subsequently wound around the outermost bundled turns of the wire of the wound spiral 1 and, finally, the synthetic resin which has been applied to the high strength fibrous material is allowed to harden. It will readily be seen that, because of the presence of the high strength fibrous material, the synthetic resin upon having been hardened is rein-forced thereby to provide the insulating layer. The syn-*hetic resin used in the practice of any of the methods of Figs. 8 and 9 may, or may not; contain a filler material.
Referring ncw to Fig. 8, prior to the high strength fibrous material 6 being wound around the bundled turns of insulated wire forming the spiral 5, the high strength fibrous material 6 is continuously immersed in a solution of synthetic resin, accommodated in a container 12, to apply the synthetic resin 13 to the high strength fibrous material 6. At the time the high strength fibous material 6 is wound around the bundled turns of insulated wire forming the wound spiral 5, the high strength fibrous material 6 is held under a predetermined tension to allow excessive synthetic resin and voids contained in the synthetic resin 13 to be removed. According to this method of Fig. 8, the high density insulating layer 8 of synthetic resin can be formed around the bundled turns of wire forming the wound spiral 5.
In the method shown in Fig. 9, at the time of winding of the high strerlgth fibrous material 6 around the bundled turns of wire of the wound spiral 5, the high strength fibrous material 6 is fed through a pair of jux-s taposed rolls 14. One of the juxtaposed rolls 14 which is rotatably supported above the other is positioned below a nozzle at the bottom of a container 12 for a solution of synthetic resin so that the latter can be supplied onto the upper roll 14 through the nozzle 16. In this arrange-ment, it will readily be understood that the solution of synthetic resin is applied to the high strength fibrous material 6 through the rolls 14. By adequately adjusting the clamping force exerted by the juxtaposed rolls 14 on the high strength fibrous material 6 passing therethrough, the high strength fibrous material 6 can be moved under a predetermined tension and subsequently wound around the bundled turns of wire of the wound spiral 5 to form the high density insulating layer 8 of synthetic resin. In a substantially similar manner to the method of Fig. 8, be-cause of the tension imparted on the high strength fibrous material 6 during the winding operation, excessive resin and voi`ds contained in the synthetic resin applied to the high str~ngth fibrous material 6 can advantageously be removed.
However, complete removal of the voids which may otherwise be left in the insulating layer 8 would be dif-ficult without, for example, the tension of the high strength iibrous material 6 being adequately controlled. In such a case it is recommended to carry ou. the winding operation .
105~91~f~
of the hiyh strcngth fibrous material 6 to which the Syh-thetic resin has already been applied, under a su~stantially vacuum atmosphere to ensure a complete removal of the voids.
Other methods of winding the high strength fibrous material having a solution of synthetic resin applied there~
to can be contemplated. One of the methods that can be contemplated is that the synthetic resin is applied to the high strength ~ibrous material by fusing by the application of heat a synthetic resin which is solid under ambient temperature and subsequently allowing it to harden after the high strength fibrous material with the synthetic resin applied thereto has been wound around the bundled turns of wire of the wound spiral 5. Another one of the methods that can be contemplated is that the synthetic resin, after having mixed with a hardening agent, is applied to the high strength fibrous material 6 and is subsequently allowed ` to assume a substantially semi-cured or semi-hardened state.
A cross sectional representation of the bundled turns of wire of the wound spiral S forming the resin packed coil assembly according to the present invention is shown in Fig. 6 wherein reference numeral 7 represents the bundled turns of wire of the wound spiral S and reference numeral 8 represents the insulàting layer 8 formed in the manner as .~ hereinbefore described.
In Fig. 7, the insulating layer 8 is depicted as composed of a plurality of, for example, three plies.
According to the present invention, since the insulating layer 8 is composed of the synthetic resin, hav-ing a thermal expansion coef$icient greater than that of g _ .
~OSlg8~
the wire of the wound spiral S, and the high strength fibrous material, such as glass, having a thermal expansion coefficient smaller than the wire of the wound spiral 5, the thermal expansion coefficient of the resultant insu-lating layer 8 can be rendered substantially equal to orapproximating to that of the wire of the wound spiral 5.
Although, during the use of the coil assembly in the external circuit, stress set-up may take place in the insulating layer 8 if there is a difference in thermal expansion coefficient, the insulating layer 8 composed of the synthetic resin reinforced by the high strength fibrous material exhibits a highly improved physical strength, even when subjected not only to a relatively low temperature and an ambient temperature, but also to a higher temperature than the heat destortion temperature of the synthetic resin used, an~, therefore, no substantial crack occur in the insulat-ing layer 8. By way of example, where glass rovings and epoxy resin are respectively employed for the high strength fibrous material 6 and the synthetic resin which is applied to the fibrous material 6, the physical strength of the resultant insulating layer 8 is about 5 times at an ambient or room temperature and about 15 times at 150 to 200~C. with respect to the physical strength exhibited by an insulating layer which is prepared solely from the epoxy resin with no high strength fibrous material added.
Furthermore, according to the present invention, since the insulating layer 8 of the sufficiently high physical strength as described above can be obtained in the construction of the coil assembly shown in any of Flgs. 6 1051~386 and 7, the concept of the present invention can be appli-cable in manufacturing a highly reliable coil assembly which can satisfactorily be operated in a highly power-loaded external circuit, which has a relatively high tem-perature resistance and which is compact in size accordingly.
In addition to the foregoing features, since thesynthetic resin of low viscosity can be employed during the manufacture of the coil assembly according to the present invention, the required time to carry out the impregnation process can advantageously be shortened with no substantial flaws, such as resulting from the presence of voids, appear-ing in the resultant,coil assembly.
According to eith~r of the methods wherein the high strength fibrous material, after having been wound around the bundled turns 7 of wire of the spiral 5, is im-pregnated with synthetic resin or wherein the high strength fibrous material, after having applied with a solution of synthetic resin, is wound around the bundled turns 7 of wire of the spiral 5, the insulating layer 8 wherein the high strength fibrous material is present in an entangled form of long fibers and is uniformly distributed can be easily be obtained completely around the bundled turns 7 of wire,of the wound spiral 5.
As hereinbefore described, the coil assembly of the construction shown in Fig. 6 is excellent in performance.
However, during the manufacture thereof, it has been found that there is a possibility that the bundled turns 7 of wire of the wound spiral 5 are not completely bonded to the insulating layer 8 of synthetic resin reinforced by--: .:. . .. ,:, , ~:;. .
10519~36 by the high strength fibrous material and that an electrically insulating layer solely composed of the synthetic resin is consequently formed between the bundled turns 7 and the in-sulatin~ layer 8. This is particularly true where the bundled turns 7 of wire of the wound spiral 5 represents a rectangular or square cross section and, since the high strength fibrous material insufficiently fills up the inter-stices among the bundled turns of wire of the wound spiral 5 if the wire has a circular cross sectional shape, only the synthetic resin is present penetrated into the inter-stices thereby forming an electrically insulating layer.
On the other hand, while the thermal expansion coefficient of the electric wire prepared from aluminum and that of the electric wire prepared from copper are respectively about 2.2 x 10 5 and 1.6 x 10 5 cm/cm/C., the thermal expansion coefficient of, for example,tepoxy resin, is 5 x 10 5 cm/cm/C. at room temperature and 5 x 10 4 cm/cm/C. at 150 to 200C. Accordingly, if the layer of only the synthetic resin is formed in the manner as hereinbefore described, considerable stresses will be set up in such resin layer as the temperature increases during the use of the coil assembly, which stresses are liable to formation of cracks. Oncè these cracks occur in the resin layer, corona discharge occur at portions of the resin layer where the cracks are fcrmed upon applica-tion of a relatively high voltage to the coil assembly and, therefore, the durability of the coil assembly is reduced.
The foregoing problem can ~e advantaseously ~ .
105~6 solved according to any of embodiments of the p~esent in-vention shown in Figs. 10 and 11, respectively.
With particular reference to Fig. 10, hetween the insulating layer 8 of synthetic resin reinforced by the high strength fibrous material and the bundled turns 7 of wire of the wound spiral 5, there is formed an inter-mediate insulating layer 9 having a relatively low thermal expansion coefficient, for example, approximate to the thermal expansion coefficient of the electric wire used to form the wound spiral 5. According to a series of experimentsconducted, it has been found that the interme-diate layer 9 is preferred to have a thermal expansion coefficient of not more than 4 x 10-5 cm/cm/C.
Material for the intermediate insulating layer 9 may be a synthetic resin admixed with an inorganic insu-lating substance or a filler of such inorganic material as silica, alumina, hydrated alumina, calci.um carbonate, magnesia, talc, clay, tinanium oxide, mica, glass and so on.
The synthetic resin admixed with the inorganic insulating material or the inorganic material as the filler cannot be satisfactorily used to form an outermost covering for the bundled turns of wire of the wound spiral. However, in the present invention, since the synthetic resin admixed with the inorganic insulating material or the inorganic material as the filler is used as a material for the inter- -;
mediate insulating layer 9 disposed between the bundled turns 7 of wire of the wound spiral 5 and the insulating layer 8, the layer 9 may have a relatively small thickness.
This is possible because the insulating layer 8 acts as a .. .
~. ' -primary insulator and, concurrently, the outermost protec-tive covering.
In view of the thickness of the intermediate layer 9 being small, the intermediate insulating layer 9 is so deformable following the stresses set up therein, so low in thermal expansion coefficient and so less liable to formation of cracks that the highly reliable coil assembly can be manufactured according to the present invention.
As a method for forming the intermediate insulat-ing layer 9, any known fluidized bed technique, electro-static fluidized bed technique, spray technique or electro-static spray technique can be employed. In the practice of any of these known techniques, the resin admixed with the inorganic insulating material or the inorganic material as the filler is applied in the form of a powder and, accordingly, the intermediate insulating layer 9 of uni-formly small thickness can readily be formed around the bundled turns 7 of wire of the wound spiral 5. Preferablv, the synthetic resin material for the layer 9 contains the inorganic material as the filler as hereinbefore described.
The synthetic resin material for the layer 9 may be epoxy resin, p~lyester resin or the like and manufacture of the coil assembly according to the pre~ent invention wherein the intermediate layer 9 is prepared from the synthetic resin with the inorganic insulating material contained therein or with the inorganic material contained therein as the filler can automatically carried out.with no substan-tially complicated procedures involved.
The intermediate insulating layer 9, even though ~05~986 it is a layer of relatively small thickness, having a suf-ficiently high physical strénqth and being so deformable as to follow the internal stresses, is less liable to formation of cracks therein. Accordingly, even in the coil assembly of the construction shown in Fig. 10, the above described advantages can be appreciated. By way of example, according to a series of experimentsconducted, it has been found that the synthetic resin material of not less than 8 kg/mm2 in bending strength and not less than 5% in elongation is more suited as a material for the intermediate insulating layer 9. Examples of the synthetic resin material for the insulating layer 9 may include a compound with metallic material and rubber or rubber-like material.
If as a material for the intermediate insulating layer 9 a porous material- is employed, the synthetic resin can, during the impregnation process, penetrate into the pores of the material forming the layer 9 to fill the pores and, therefore, the level at which corona dis-charge takes place and the impulse surge in the resultant coil assem~ly can advantageously be improved. It is to be noted that the synthetic resin which has penetrated into the pores of the material forming the intermediate layer 9 is subsequently hardened and, therefore, if such a porous material which, when hardened, exhibits a rela-tively low thermal expansion coefficient, has a relatively high physical strength or has a relatively high elongation, the layer 9 composed of such synthetic material can serve as an insulator.
' 1o5~986 - On the other hand, if the intermediate layer 9 can exhibit a property similar to a semi-conductor having an appropriate resistance, no substantial potential diffe-rence will be created in the layer 9 even if the latter has voids and/or cracks therein, and corona discharge will hardly occur. In the embodiment shown in Fig. 12, while the intermediate layer 9 serves as an insulator, a semi-conductive or conductive layer 10 is formed between the layer 9 and the layer 8 composed of the synthetic resin reinforced by the high strength fibrous material as herein-before described. In this construction as shown in Fig. 12, since the semi-conductive layer 10 does not directly con-tact the outermost turns of the bundled turns 7 of wire of the wound spiral 5, not only the leakage potential level at the outermost turns of the bundled turns 7 can advantageously be minimized, but also an effect of relief of the electric field of the semi-conductive layer 10 can be expected as hereinbefore described.
In the embodiment shown in Fig. 13, the semi-2~ conductive or conductive layer 10 is compo~ed of inner and outer semi-conductive or conductive plies 10a and 10b with a gap 11 located between the outer and inner plies lQb and 10a. Material for the inner and outer plies 10a and 10b and, therefore, the layer 10, may be any con-ductive material, such as carbon, a sheet containing carbon,a metallic compound or a metal, or synthetic resin.
During the operation of the coil assembly of the con-struction shown in Fig. 13, since the potential of either of the inner and outer plies 10a and 5198~
lOb is substantially equalized to that of the other of the inner and outer plies lOa and lOb over the outermost turns of the bundled turns 7 of wire of the wound spiral 5, no potential differer.ce is substantially created in the gap 11 and, therefore, no corona discharge occurs. Ano-ther advantage resulting from the provision of the gap 11 is that the gap 11 absorbs variation in volume of any of the inner and outer plies lOa and lOb which may result from variation of the ambient temperature, vari-ation of the operating temperature of the coil assembly ;Y--and/or variation in dimension due to aging and that the internal stresses can, therefore, be relieved.
With the construction shown in Fig. 13, in addi-tion to the internal stress relief achieved in the manner as hereinbefore described, the effect of electric field relief can also be attained in a manner similar to the construction shown in Fig. 12.
Still referring to Fig. 13, the inner and outer plies lOa and lOb of the semi-conductive or conductive layer 10 are preferably firmly bonded to the intermediate layer 9 and the synthetic resin layer ~, respectively.
This can be achieved by applying a synthetic resin, such as a semi-conductive powdery synthetic resin, to the outer peripheral surface of the layer ~, subsequently applying, or otherwise, lining such a material having a parting property as silicon or tetrafluoroethylene over the applied synthetic resin, thereafter winding the high strength fibrous material after a semi-conductive material, such as a carhon sheet, has been wound around the applied synthetic ~-.
~051986 resin, and finally hardening the synthetic resin material after the assembly has been dipped in a solution of the synthetic resin material. The gap 11 herein referred to is not of a type having a uniform thickness between the inner and outer plies lOa and lOb and, in other words, is not chemically bonded to any of the inner and outer plies lOa and lOb. In practice, this gap 11 allows the inner and outer plies lOa and~lOb of the semi-conductive or conductive layer 10 to contact to each other at local positions and, accordingly, during the operation of the coil assembly, the plies lOa and lOb are charged the sub-stantially equal potential.
While the employment of the plies lOa and lOb are preferred, either the inner ply lOa or the outer ply lOb may be omitted if the gap 11 is sufficiently small`in thickness.
If in the construction shown in any of Figs. 12 and 13 the wire forming the bundled turns 7 of the wound spiral 5 is highly insulated or if the induced voltage between one layer and another of the coil assembly is sufficiently low, there may be provided the semi-conductive layer 10 between the bùndled turns 7 of wire of the wound spiral 5, and the layer 9 such as shown in Fig. 14. In this case, even if the insulated wire forming the bundled turns 7 of the wound spiral 5 does not exhibit a sufficient ~ `
bondability with~respect to the material of the layer which is held in contact therewith, the effect of electric field relief can be attained by the semi-conductive layer 10 between the bundled turns 7 and the layer 9.
The insulated wire employed to form the electro-magnetic coil assembly of any of the constructions shown in Figs. 3 to 14 is preferably employed in the form of a ~elf-fusible wire, that is, a wire sheathed with a thermo-plastic material. If this type of wire is employed and subsequently coiled to form the bundled turns 7, the bun-dled turns 7 can easily be obtained with one turn firmly bonding to adjacent turns upon application of heat thereto.
Therefore, any auxiliary elements, such as a temporarily binding tape, is not required to retain the shape of the bundled turns 7 of wire of the wound spiral 5 prior to the formation of the layer to be contacted to the outermost turns of the bundled turns 7 of wire of the wound spiral 5.
Furthermore, since an insulating sheet between the layers can be removed, the electromagnetic coil assembly, compact in size, can effectively and readily be manufactured at a high production rate.
Although the present invention has been fully described by way of the preferred embodiments thereof, it should be noted that various changes and modifications are ~`
apparent to those skilled in the art. Such changes and ;~
modifications, unless they depart from the true scope of the present invention, should be construed as included therein.
~ .:
,; , ~ ' .. .
' - -- 19 --
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A synthetic resin packed coil assembly which is impregnated at the outer periphery thereof with synthetic resin layer including therein a high strength fibrous material, said coil assembly comprising;
a wound spiral of a plurality of bundled turns of insulated wire, an intermediate insulating layer formed between said wound spiral and said synthetic resin layer including the high strength fiber material and, a semi-conductive layer further formed between said intermediate insulating layer and said synthetic resin layer, said semi-conductive layer being constituted by a first ply integrally formed with said intermediate insulating layer and also a second ply integrally formed with said synthetic resin layer including the high strength fibrous material, with an air gap layer being further formed between said first and second plies over the entire peripheral surface for preventing chemical adhesion between said intermediate insulating layer and synthetic resin layer.
a wound spiral of a plurality of bundled turns of insulated wire, an intermediate insulating layer formed between said wound spiral and said synthetic resin layer including the high strength fiber material and, a semi-conductive layer further formed between said intermediate insulating layer and said synthetic resin layer, said semi-conductive layer being constituted by a first ply integrally formed with said intermediate insulating layer and also a second ply integrally formed with said synthetic resin layer including the high strength fibrous material, with an air gap layer being further formed between said first and second plies over the entire peripheral surface for preventing chemical adhesion between said intermediate insulating layer and synthetic resin layer.
2. As assembly as claimed in Claim 1, wherein said intermediate insulating layer is made of a synthetic resin having a thermal expansion coefficient of not more than 4 x 10-5 cm/cm/°C. at an ambient temperature.
3. An assembly as claimed in Claim 2, wherein said intermediate layer comprises a synthetic resin admixed with an inorganic insulating substance or a filler of inorganic material.
4. An assembly as claimed in Claim 2 wherein said inter-mediate layer comprises a powdery resinous material applied to the outermost turns of said wound spiral.
5. An assembly according to Claim 2 wherein said inter-mediate layer has a bending strength of not less than 8 kg/mm2 and an elongation of not less than 5%.
6. An assembly as claimed in Claim 1, wherein said insulated wire is a self-fusible resin sheathed wire.
7. An assembly as claimed in Claim 2, 3 or 5 wherein said intermediate layer synthetic resin is a porous synthetic resin.
8. An assembly as claimed in Claim 4, wherein said powdery resinous material is prepared from a porous synthetic resin having an insulating property.
Applications Claiming Priority (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP49108529A JPS5135057A (en) | 1974-09-19 | 1974-09-19 | |
| JP49108528A JPS5135056A (en) | 1974-09-19 | 1974-09-19 | |
| JP10853274A JPS5135060A (en) | 1974-09-19 | 1974-09-19 | JUSHIHOMAIKOIRU |
| JP49108533A JPS5136566A (en) | 1974-09-19 | 1974-09-19 | Jushihomaikoiru no seizohoho |
| JP49108531A JPS593845B2 (en) | 1974-09-19 | 1974-09-19 | Jyuushihou My Coil |
| JP49108530A JPS5135058A (en) | 1974-09-19 | 1974-09-19 | |
| JP49109098A JPS5136528A (en) | 1974-09-20 | 1974-09-20 | |
| JP50006565A JPS604587B2 (en) | 1975-01-14 | 1975-01-14 | Manufacturing method of resin-embedded coil |
| JP50047030A JPS51121768A (en) | 1975-04-17 | 1975-04-17 | Resin mould coil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1051986A true CA1051986A (en) | 1979-04-03 |
Family
ID=27576528
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA235,888A Expired CA1051986A (en) | 1974-09-19 | 1975-09-19 | Synthetic resin packed coil assembly |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1051986A (en) |
| DE (1) | DE2541670C2 (en) |
| FR (1) | FR2285693A1 (en) |
| GB (1) | GB1525745A (en) |
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|---|---|---|---|---|
| ES240801Y (en) * | 1979-01-17 | 1979-08-16 | DEMAGNETISING COIL WITH DOUBLE PROTECTION. | |
| DE2945480A1 (en) * | 1979-11-10 | 1981-05-21 | Brown, Boveri & Cie Ag, 6800 Mannheim | Coil for high current electrical machines - is made from high conductivity bars and uses copper or aluminium strip coated with glass fibre layer |
| FR2630253A1 (en) * | 1988-04-19 | 1989-10-20 | Alsthom | METHOD FOR IMPROVING THE FIRE RESISTANCE OF A DRY ELECTRICAL TRANSFORMER |
| DE3910591A1 (en) * | 1989-04-01 | 1990-10-04 | Asea Brown Boveri | Winding for an inductive electrical apparatus |
| EA001173B1 (en) | 1996-05-29 | 2000-10-30 | Абб Аб | Insulated conductor for high-voltage windings and a method of manufacturing the same |
| SE510192C2 (en) | 1996-05-29 | 1999-04-26 | Asea Brown Boveri | Procedure and switching arrangements to reduce problems with three-tier currents that may occur in alternator and motor operation of AC machines connected to three-phase distribution or transmission networks |
| DE69728972T2 (en) | 1996-05-29 | 2005-05-04 | Abb Ab | TRANSFORMER / REACTOR |
| SE9602079D0 (en) | 1996-05-29 | 1996-05-29 | Asea Brown Boveri | Rotating electric machines with magnetic circuit for high voltage and a method for manufacturing the same |
| ATE250817T1 (en) | 1996-05-29 | 2003-10-15 | Abb Ab | CONDUCTOR FOR HIGH VOLTAGE WINDINGS AND ROTATING ELECTRICAL MACHINE HAVING SUCH A CONDUCTOR |
| SE509072C2 (en) | 1996-11-04 | 1998-11-30 | Asea Brown Boveri | Anode, anodizing process, anodized wire and use of such wire in an electrical device |
| SE515843C2 (en) | 1996-11-04 | 2001-10-15 | Abb Ab | Axial cooling of rotor |
| SE512917C2 (en) | 1996-11-04 | 2000-06-05 | Abb Ab | Method, apparatus and cable guide for winding an electric machine |
| SE510422C2 (en) | 1996-11-04 | 1999-05-25 | Asea Brown Boveri | Magnetic sheet metal core for electric machines |
| SE508543C2 (en) | 1997-02-03 | 1998-10-12 | Asea Brown Boveri | Coiling |
| SE9704423D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Rotary electric machine with flushing support |
| SE9704431D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Power control of synchronous machine |
| SE9704422D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | End plate |
| SE9704421D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Series compensation of electric alternator |
| SE9704427D0 (en) | 1997-02-03 | 1997-11-28 | Asea Brown Boveri | Fastening device for electric rotary machines |
| SE508544C2 (en) | 1997-02-03 | 1998-10-12 | Asea Brown Boveri | Method and apparatus for mounting a stator winding consisting of a cable. |
| DE29706403U1 (en) * | 1997-04-11 | 1997-07-31 | Herberts Gmbh, 42285 Wuppertal | Wire for windings of electrical machines |
| GB2331867A (en) | 1997-11-28 | 1999-06-02 | Asea Brown Boveri | Power cable termination |
| GB2331852A (en) * | 1997-11-28 | 1999-06-02 | Asea Brown Boveri | Transformer winding arrangements |
| BR9815420A (en) | 1997-11-28 | 2001-07-17 | Abb Ab | Method and device for controlling the magnetic flux with an auxiliary winding on a rotating high voltage alternating current machine |
| GB2331854A (en) * | 1997-11-28 | 1999-06-02 | Asea Brown Boveri | Transformer |
| US6801421B1 (en) | 1998-09-29 | 2004-10-05 | Abb Ab | Switchable flux control for high power static electromagnetic devices |
| CN109378919B (en) * | 2018-12-12 | 2024-02-20 | 哈尔滨电气动力装备有限公司 | Stator bar winding end insulation structure of canned motor |
| CN114696563A (en) * | 2020-12-30 | 2022-07-01 | 中国航天科工飞航技术研究院（中国航天海鹰机电技术研究院） | Structure assembly of linear motor stator winding and stator winding track installation method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD75352A (en) * | ||||
| BE469545A (en) * | 1945-07-20 | |||
| CH268951A (en) * | 1948-10-05 | 1950-06-15 | Oerlikon Maschf | Current transformer with windings embedded in a solid insulating compound. |
| US3297970A (en) * | 1965-04-07 | 1967-01-10 | Gen Electric | Electrical coil and method of manufacturing |
| DE1479428C3 (en) * | 1965-07-12 | 1975-09-25 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Method for wrapping devices |
| US3462544A (en) * | 1967-08-29 | 1969-08-19 | Us Navy | Electrical conductors with a heat resistant electrical insulation system |
| DE2256161A1 (en) * | 1971-11-18 | 1973-05-24 | Gen Electric | METHOD OF INSULATING ELECTRIC COILS |
-
1975
- 1975-09-18 DE DE19752541670 patent/DE2541670C2/en not_active Expired
- 1975-09-18 GB GB3841575A patent/GB1525745A/en not_active Expired
- 1975-09-18 FR FR7528673A patent/FR2285693A1/en active Granted
- 1975-09-19 CA CA235,888A patent/CA1051986A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2541670C2 (en) | 1986-09-04 |
| FR2285693B1 (en) | 1980-03-07 |
| DE2541670A1 (en) | 1976-04-01 |
| FR2285693A1 (en) | 1976-04-16 |
| GB1525745A (en) | 1978-09-20 |
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