CA1257668A - Heating coil assembly for an electromagnetic induction cooking heater and method for the same manufacturing the same - Google Patents
Heating coil assembly for an electromagnetic induction cooking heater and method for the same manufacturing the sameInfo
- Publication number
- CA1257668A CA1257668A CA000524667A CA524667A CA1257668A CA 1257668 A CA1257668 A CA 1257668A CA 000524667 A CA000524667 A CA 000524667A CA 524667 A CA524667 A CA 524667A CA 1257668 A CA1257668 A CA 1257668A
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- winding
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- space
- base
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Abstract
ABSTRACT OF THE DISCLOSURE
In a method of manufacturing a heating coil assembly for electromagnetic induction cooking heater in which a coil supporting base and a flat shaped coil winding frame are mounted on the spindle of a coil winding machine in such a manner as to form a coil receiving space there-between, and a wire is wound in the space to form a coil, the coil supporting base and/or the coil winding frame has protrusions which extend in the space at the middle part, to vary the coil winding pitch t whereby the coil thus formed has a gap at the middle part, thus showing a uniform temperature distribution when energized.
In a method of manufacturing a heating coil assembly for electromagnetic induction cooking heater in which a coil supporting base and a flat shaped coil winding frame are mounted on the spindle of a coil winding machine in such a manner as to form a coil receiving space there-between, and a wire is wound in the space to form a coil, the coil supporting base and/or the coil winding frame has protrusions which extend in the space at the middle part, to vary the coil winding pitch t whereby the coil thus formed has a gap at the middle part, thus showing a uniform temperature distribution when energized.
Description
;8 l BACKGROUND OF THE INVENTION
This invention relates to heating coil assemblies for electromagnetic lnduction cooking heater, and methods for manu-facturing the heating coil assemblies, more particularly, to heating coil assemblies having larger coil winding pitch at the middle part between the outer and inner circum-ferential parts thereof and methods for manufacturing the same.
The nature, utility and principle of the invention will become more apparent from the following detailed de-scription and the appended claims when read in conjunctionwith the accompanying drawings.
B~IEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are a sectional view and a perspec-tive view, respectively, showing a first example of a heating coil assembly for electromagnetic induction cooking heater which ismanufactured according to one example of a heating coil assembly manufacturing method of the invention;
FIGS. 3 and 4 are a sectional view and a perspec-tive view, respectively, showing another example of the heating coil assembly which is manufactured according toanother example of the heating coil assembly manufacturing method of the invention in such a manner that the coil has a gap at the middle part which is located between the outer-and inner peripheral parts of the coil;
~2~
1 FIGS. 5 and 6 are a sectional view and a perspec-tive view, respectively/ showing the same heating coil assembly as that shown in FIGS. 3 and 4 which is now manu-factured according to another example of the heating coil assembly manufacturing method of the invention in which spacers are used.to form the gap in the coil;
FIG. 7 is a perspective view for a description of the difficulty that, where the coil supporting base has no protrusions, the coil is deformed.
FIG. 8 is a graphical representation for a de-scription of the temperature distribution of the heating coil assembly of the invention in comparison with that of a conventional heating coil assembly;
FIG. 9 is a sectional view showing another example of the heating coil assembly manuacturing method of the invention in which the coil winding frame has the pro-trusions;
FIG. 10 is a sectional view showing another example of the heating coil assembly manufacturing method of the invention in which the protrusions are formed both on the coil supporting base and on the coil winding frame;
FIGS. 11 and 12 are a sectional view and a perspective view, respectively, showing a conventional heating coil assembly for electromagnetic induction cooking heater;
and FIG. 13 is a plan view for a description of a method of preventing the permeation of impregnating varnish into the lead wires of the coil.
, ~
6~
1 An electromagnetic induction ox~ing heater compri~s a heating coil assembly. The coil assembly is generally manufactured as follows: As shown in FIGS. 11 and 12, a Litz wire 3 consisting of a number of separately insulated strands of enameled wires is wound spirally and secured to a coil supporting base2 with varnish. More specifically, as shown in FIG. 5, the coil supporting base ~ and a coil winding frame 1 are fixedly mounted on the shaft of a coil winding machine in such a manner that a space for receiving the Litz wire 3 is formed therebetween, and then the Litz wire 3 is spirally wound in the space.
The coil manufacturing method is advantageous in that the number of manufacturing steps is relatively small and the productivity is high.
However, in the heating coil assembly manufactured according to the above-described conventional coil manufac-turing method, the Litz wire is uniformly and closely wounded as is apparent from FIG. 11, thus providing the following difficulty: When the heating coil is energized, the middle part of the heating coil, located between the inner and outer parts thereof, becomes higher in magnetic flux density than any other parts. Therefore, when a cooking utensil to be heated, such as a pan, is placed over the heating coil, its part confronting the middle part of the heating coil is heated more than the other 76~
1 parts. This phenomenon may result in the difficulty that, especially in preparing food by baking, the food is non-uniformly baked.
In order to eliminate the difficulty, a method has been proposed in the art in which the coil winding pitch is made smaller towards the outer periphexy of the coil (cf. Japanese Patent Application Laid-Open No.
56743/1981). However, the method is low in productivity and h~gh in manufacturing cost, because it is necessary to prepare a plastic spacer for manufacture of each coil and the wire is wound on the spacer.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of this invention is to provide a heating coil assembly in which the coil wound spirally has a gap at its middle part which is located between the outer and inner parts of the coil, thereby to eliminate the above-described difficulties ac-companying a conventional heating coil assembly.
Another object of the invention is to provide a method of manufacturing the above-described heating coil assembly with high productivity.
The foregoing objects and other objects of the invention have been achieved by the provision of a coil assembly which, according to the invention, comprises: a flat shaped coil support base; and a coil formed on the ~25~
1 coil base by spirally winding a stranded wire in such a manner that a gap is formed in the coil at the mlddle part thereof, and by the provision of a coil assembly manu-facturing method in which a flat shaped coil support base and a flat shaped coil winding frame are fixedly mounted on the output shaft of a coil winding machine in such a manner that the coil base and the coil windinq frame define a coil receiving space, and a stranded wire is wound spirally in the space to form a coil therein, in which, according to the invention, the coil base and/or coil winding frame has a plurality of protrusions which extend in the space at the middle part, which is located between the outer and inner peripheries of the space, thereby to change the coil winding pitch.
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of this invention will be described with reference to the accompanying drawings.
_ 5 _ ~57~
A first example of a heating coil assembly for electromagnetic induction cooking hea-ter according to ~he in~ention, as shown in FIGS. 1 and 2, comprises a coil supporting base 2 having pro-trusions 8 at the middle part thereof;
and a spiral coil 3 formed on the coil supporting base 2.
The coil is generally formed as follows: A coil winding frame 1 is placed on the coil supporting base 2, and a stranded wire is spirally wound in the space 7 formed between the coil winding frame 1 a~d the coil supporting base 2. In this case, the gap between the frame 1 and the base 2 at each of the protrusions 8 of the base 2 is smaller than that at any other part, and therefore, at the pro-trusions 8, the stranded wire is flattened and its winding pitch is increased as much.
Thus, the winding pitch of the spiral coil can be readily changed according to the method of the in~ention.
In the present invention, the stranded wire preferably has a stranding pitch which is more than twenty times as large as the outside diameter of the stranded wire.
Alternatively, the stranded wire may be a plurality oE
enameled wires boundled together~
FIGS. 3 and 4 show a second example of the heating coil assembly manufactured according to a-second example of the coil manufacturing method of the invention.
In the heating coil assembly, a gap G is provided a-t the middle part of a coil 3, between the outer and inner parts.
~,2~76~8 In the coil manufacturing method, forming the coil 3 is started after, on the wire supplying side, the backward tension given to the wire has been set relatively high.
As a winding machine (not shown) is rotated, a coil supporting base 2 and a coil winding frame 1 mounted or:. the output shaft of the winding machine are turned so that the stranded wire is wound in the space 7 between the coil supporting base 2 and the coil winding frame le In this operation, since the coil supporting base
This invention relates to heating coil assemblies for electromagnetic lnduction cooking heater, and methods for manu-facturing the heating coil assemblies, more particularly, to heating coil assemblies having larger coil winding pitch at the middle part between the outer and inner circum-ferential parts thereof and methods for manufacturing the same.
The nature, utility and principle of the invention will become more apparent from the following detailed de-scription and the appended claims when read in conjunctionwith the accompanying drawings.
B~IEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are a sectional view and a perspec-tive view, respectively, showing a first example of a heating coil assembly for electromagnetic induction cooking heater which ismanufactured according to one example of a heating coil assembly manufacturing method of the invention;
FIGS. 3 and 4 are a sectional view and a perspec-tive view, respectively, showing another example of the heating coil assembly which is manufactured according toanother example of the heating coil assembly manufacturing method of the invention in such a manner that the coil has a gap at the middle part which is located between the outer-and inner peripheral parts of the coil;
~2~
1 FIGS. 5 and 6 are a sectional view and a perspec-tive view, respectively/ showing the same heating coil assembly as that shown in FIGS. 3 and 4 which is now manu-factured according to another example of the heating coil assembly manufacturing method of the invention in which spacers are used.to form the gap in the coil;
FIG. 7 is a perspective view for a description of the difficulty that, where the coil supporting base has no protrusions, the coil is deformed.
FIG. 8 is a graphical representation for a de-scription of the temperature distribution of the heating coil assembly of the invention in comparison with that of a conventional heating coil assembly;
FIG. 9 is a sectional view showing another example of the heating coil assembly manuacturing method of the invention in which the coil winding frame has the pro-trusions;
FIG. 10 is a sectional view showing another example of the heating coil assembly manufacturing method of the invention in which the protrusions are formed both on the coil supporting base and on the coil winding frame;
FIGS. 11 and 12 are a sectional view and a perspective view, respectively, showing a conventional heating coil assembly for electromagnetic induction cooking heater;
and FIG. 13 is a plan view for a description of a method of preventing the permeation of impregnating varnish into the lead wires of the coil.
, ~
6~
1 An electromagnetic induction ox~ing heater compri~s a heating coil assembly. The coil assembly is generally manufactured as follows: As shown in FIGS. 11 and 12, a Litz wire 3 consisting of a number of separately insulated strands of enameled wires is wound spirally and secured to a coil supporting base2 with varnish. More specifically, as shown in FIG. 5, the coil supporting base ~ and a coil winding frame 1 are fixedly mounted on the shaft of a coil winding machine in such a manner that a space for receiving the Litz wire 3 is formed therebetween, and then the Litz wire 3 is spirally wound in the space.
The coil manufacturing method is advantageous in that the number of manufacturing steps is relatively small and the productivity is high.
However, in the heating coil assembly manufactured according to the above-described conventional coil manufac-turing method, the Litz wire is uniformly and closely wounded as is apparent from FIG. 11, thus providing the following difficulty: When the heating coil is energized, the middle part of the heating coil, located between the inner and outer parts thereof, becomes higher in magnetic flux density than any other parts. Therefore, when a cooking utensil to be heated, such as a pan, is placed over the heating coil, its part confronting the middle part of the heating coil is heated more than the other 76~
1 parts. This phenomenon may result in the difficulty that, especially in preparing food by baking, the food is non-uniformly baked.
In order to eliminate the difficulty, a method has been proposed in the art in which the coil winding pitch is made smaller towards the outer periphexy of the coil (cf. Japanese Patent Application Laid-Open No.
56743/1981). However, the method is low in productivity and h~gh in manufacturing cost, because it is necessary to prepare a plastic spacer for manufacture of each coil and the wire is wound on the spacer.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of this invention is to provide a heating coil assembly in which the coil wound spirally has a gap at its middle part which is located between the outer and inner parts of the coil, thereby to eliminate the above-described difficulties ac-companying a conventional heating coil assembly.
Another object of the invention is to provide a method of manufacturing the above-described heating coil assembly with high productivity.
The foregoing objects and other objects of the invention have been achieved by the provision of a coil assembly which, according to the invention, comprises: a flat shaped coil support base; and a coil formed on the ~25~
1 coil base by spirally winding a stranded wire in such a manner that a gap is formed in the coil at the mlddle part thereof, and by the provision of a coil assembly manu-facturing method in which a flat shaped coil support base and a flat shaped coil winding frame are fixedly mounted on the output shaft of a coil winding machine in such a manner that the coil base and the coil windinq frame define a coil receiving space, and a stranded wire is wound spirally in the space to form a coil therein, in which, according to the invention, the coil base and/or coil winding frame has a plurality of protrusions which extend in the space at the middle part, which is located between the outer and inner peripheries of the space, thereby to change the coil winding pitch.
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of this invention will be described with reference to the accompanying drawings.
_ 5 _ ~57~
A first example of a heating coil assembly for electromagnetic induction cooking hea-ter according to ~he in~ention, as shown in FIGS. 1 and 2, comprises a coil supporting base 2 having pro-trusions 8 at the middle part thereof;
and a spiral coil 3 formed on the coil supporting base 2.
The coil is generally formed as follows: A coil winding frame 1 is placed on the coil supporting base 2, and a stranded wire is spirally wound in the space 7 formed between the coil winding frame 1 a~d the coil supporting base 2. In this case, the gap between the frame 1 and the base 2 at each of the protrusions 8 of the base 2 is smaller than that at any other part, and therefore, at the pro-trusions 8, the stranded wire is flattened and its winding pitch is increased as much.
Thus, the winding pitch of the spiral coil can be readily changed according to the method of the in~ention.
In the present invention, the stranded wire preferably has a stranding pitch which is more than twenty times as large as the outside diameter of the stranded wire.
Alternatively, the stranded wire may be a plurality oE
enameled wires boundled together~
FIGS. 3 and 4 show a second example of the heating coil assembly manufactured according to a-second example of the coil manufacturing method of the invention.
In the heating coil assembly, a gap G is provided a-t the middle part of a coil 3, between the outer and inner parts.
~,2~76~8 In the coil manufacturing method, forming the coil 3 is started after, on the wire supplying side, the backward tension given to the wire has been set relatively high.
As a winding machine (not shown) is rotated, a coil supporting base 2 and a coil winding frame 1 mounted or:. the output shaft of the winding machine are turned so that the stranded wire is wound in the space 7 between the coil supporting base 2 and the coil winding frame le In this operation, since the coil supporting base
2 has protrusions 8 on its uppèr surface as is shown best in FIG. 3 and the space 7 is made narrower at the protrusions 8, while the backward tension is maintained high the wire is deformed while passing over the protrusions 8, thus being wound along the inner circumference of the space 7.
After the output shaft of the coil winding machine has made a predetermined number of revolutions, the backward tension is decreased so that the wire is prevented from passing over the protrusions 8 and it is wound along the latter 8.
Accordingly, the aforementioned gap G can be readily formed at the middle part of the coil.
In the above~described method, the heating coil assembly is manufactured by changing the backward tension given to the wire. However, the same heat coil assembly can be manufactured according to a third example of the heating coil assembly manufacturing method accordin~ to the invention in which spacers turning in synchronization with the output shaft of a coil winding machine are em-ployed as shown in FIGS. 5 and 6.
More specifically, the spacers 6 are pins whichar.e embedded in a disc 5 in such a manner that they are arranged on a circumference coaxal with the disc 5. The di.sc 5 is mounted on the output s~aft`of the coil winding 10 machine.
Forming a coil 3 is started in the same manner as that in the second example of the heating coil assembly manufacturing method shown in FIGS. 3 and 4.
After the coil 3 has had predetermined turns the .5 spacers 6 are pushed towards the coil 3 together with the d sc. Under this condition, the coil winding machine is rotated again. Therefore, the wire ~s now wound along the spacers 6 to form the outer part of the coil.
Thus, the coil 3 having the gap G at its middle part can be manufactured according to thP third example of the heating coil assembly manufacturing method of the invention.
The coil 3 thus formed the coil supporting base 2 and the coil winding frame 1 are fixedly combined together with screws or the like, and then are removed from the ~257~
output shaft of the coil winding machine. Thereafter, the coil is bonded to the coil supporting base with adhesive such as impregnating varnish.
In the above-described operation, when the coll
After the output shaft of the coil winding machine has made a predetermined number of revolutions, the backward tension is decreased so that the wire is prevented from passing over the protrusions 8 and it is wound along the latter 8.
Accordingly, the aforementioned gap G can be readily formed at the middle part of the coil.
In the above~described method, the heating coil assembly is manufactured by changing the backward tension given to the wire. However, the same heat coil assembly can be manufactured according to a third example of the heating coil assembly manufacturing method accordin~ to the invention in which spacers turning in synchronization with the output shaft of a coil winding machine are em-ployed as shown in FIGS. 5 and 6.
More specifically, the spacers 6 are pins whichar.e embedded in a disc 5 in such a manner that they are arranged on a circumference coaxal with the disc 5. The di.sc 5 is mounted on the output s~aft`of the coil winding 10 machine.
Forming a coil 3 is started in the same manner as that in the second example of the heating coil assembly manufacturing method shown in FIGS. 3 and 4.
After the coil 3 has had predetermined turns the .5 spacers 6 are pushed towards the coil 3 together with the d sc. Under this condition, the coil winding machine is rotated again. Therefore, the wire ~s now wound along the spacers 6 to form the outer part of the coil.
Thus, the coil 3 having the gap G at its middle part can be manufactured according to thP third example of the heating coil assembly manufacturing method of the invention.
The coil 3 thus formed the coil supporting base 2 and the coil winding frame 1 are fixedly combined together with screws or the like, and then are removed from the ~257~
output shaft of the coil winding machine. Thereafter, the coil is bonded to the coil supporting base with adhesive such as impregnating varnish.
In the above-described operation, when the coll
3, the base 2 and frame 1 are removed from the coil winding machine, simultaneously the spacers 6 for forming the gap G are disengaged from the coil 3. Therefore, the part B
o the wire which crosses over the gap (hereinafter referred tc "a crossover part or wire ~", when applicable) is dis~
placed by the elasticity of the wire itself as shown in FIG. 7; that is, it is difficult to maintain the configura-tion of th~ coil unchanged.
The above-described difficulty a~companying the~
third example of the heating coll assembly manufacturing method can be eliminated by providing protrusions 8 as shown in FIGS. 1 and 2 in such a manner that the protrusions 8 are arranged along the outer periphery of the gap G. That is, the protrusions 8 thus provided prevents the displace-ment of the crossover wire which otherwise may be caused by the elasticity of the wire. Thus, the heating coil assembly whose coil has a predetermined gap at the middle part can be readily mass-produced.
When the coil is secured to the coil base with impregnating varnish, both end portions C and D (shown in FIG. 13) of the coil are preferably applied with varnish ~2~;7~
which, at high temperature, is low in fluidity or hardened . quickly, whereby permea-tion oE the impregnating varnish into the lead wires connected to the two end portions of the coil is prevented and flexible lead wires are formed.
In the heating coil assembly of FIG. 1, the coil-supporting base 2 has a plurality of protrusions 8 at the middle part. However, it should be noted that the invention is not limited thereto or thereby. That is, the coil sup-porting base 2 may have only one protrusion 80 In this .10 c.~se also, the protrusion can effectively prevent the : d:isplacement of the crossover wire, although the plural p;:otrusisns 8 can prevent the displacement of the crossover w:ire more effectively than the one protrusion.
In the above-described heating coil manuEacturing methods of the invention, the coil supporting base has the protrusions 8. However, the same effect can be obtained b~ a method in which protrusions 8' are formed on the coil wi.nding frame as shown in FIG. 9, or protrusions 8 and 8' are formed both on the coil supporting base 2 and on the coil winding frame 1.as.:shcwn in FIG;10. In FIGS. 9 and 10, reference numeral 3 designates the coil formed on the coil supporting base 2.
FIG. 8 is a graphical representation indicating the temperature distribution P of the conventional heating coil assembly and that Q of the heating coil assembly of ~L%5766~3 the invention, It is apparent from FIG. 8 that the heating eo~l assembly of the invention in whieh the coil has the gap at the middle part is mueh uniform in temperature distribution than the eonventional heati.ng eoil assembly.
As was described above, according to the invention, the protrusions are formed on the eoil supporting base and/or the coil winding frame, whereby the coil winding pitch can be readily ehanged at the middle part of the eoil, between the outer and inner parts. Aceordingly, the heating coil assembly for eleetromagnetic induction eooking heater a-eording to the invention is uniform in heating charaeter~
istie.:
o the wire which crosses over the gap (hereinafter referred tc "a crossover part or wire ~", when applicable) is dis~
placed by the elasticity of the wire itself as shown in FIG. 7; that is, it is difficult to maintain the configura-tion of th~ coil unchanged.
The above-described difficulty a~companying the~
third example of the heating coll assembly manufacturing method can be eliminated by providing protrusions 8 as shown in FIGS. 1 and 2 in such a manner that the protrusions 8 are arranged along the outer periphery of the gap G. That is, the protrusions 8 thus provided prevents the displace-ment of the crossover wire which otherwise may be caused by the elasticity of the wire. Thus, the heating coil assembly whose coil has a predetermined gap at the middle part can be readily mass-produced.
When the coil is secured to the coil base with impregnating varnish, both end portions C and D (shown in FIG. 13) of the coil are preferably applied with varnish ~2~;7~
which, at high temperature, is low in fluidity or hardened . quickly, whereby permea-tion oE the impregnating varnish into the lead wires connected to the two end portions of the coil is prevented and flexible lead wires are formed.
In the heating coil assembly of FIG. 1, the coil-supporting base 2 has a plurality of protrusions 8 at the middle part. However, it should be noted that the invention is not limited thereto or thereby. That is, the coil sup-porting base 2 may have only one protrusion 80 In this .10 c.~se also, the protrusion can effectively prevent the : d:isplacement of the crossover wire, although the plural p;:otrusisns 8 can prevent the displacement of the crossover w:ire more effectively than the one protrusion.
In the above-described heating coil manuEacturing methods of the invention, the coil supporting base has the protrusions 8. However, the same effect can be obtained b~ a method in which protrusions 8' are formed on the coil wi.nding frame as shown in FIG. 9, or protrusions 8 and 8' are formed both on the coil supporting base 2 and on the coil winding frame 1.as.:shcwn in FIG;10. In FIGS. 9 and 10, reference numeral 3 designates the coil formed on the coil supporting base 2.
FIG. 8 is a graphical representation indicating the temperature distribution P of the conventional heating coil assembly and that Q of the heating coil assembly of ~L%5766~3 the invention, It is apparent from FIG. 8 that the heating eo~l assembly of the invention in whieh the coil has the gap at the middle part is mueh uniform in temperature distribution than the eonventional heati.ng eoil assembly.
As was described above, according to the invention, the protrusions are formed on the eoil supporting base and/or the coil winding frame, whereby the coil winding pitch can be readily ehanged at the middle part of the eoil, between the outer and inner parts. Aceordingly, the heating coil assembly for eleetromagnetic induction eooking heater a-eording to the invention is uniform in heating charaeter~
istie.:
Claims (16)
1. A coil assembly manufacturing method, comprising the steps of: mounting flat shaped coil support base and a flat shaped coil winding frame fixedly on the output shaft of a coil winding machine in such a manner that said coil base and said coil winding frame define a coil receiving space; and winding a stranded wire in said space to form a coil therein, said coil base and/or coil winding frame having a plurality of protrusions which extend in said space at the middle part between the outer and inner peripheral parts of said space, thereby to change the coil winding pitch.
2. A method as claimed in claim 1, in which protru-sions are formed on said coil base in such a manner that said protrusions are located at the middle part of said space, thereby to form a gap in said coil at the middle part thereof.
3. A method as claimed in claim 1, in which protru-sions are formed on said coil winding frame in such a manner that said protrusions are located at the middle part of said space, thereby to form a gap in said coil at the middle part thereof.
4. A method as claimed in claim 1, in which protru-sions are formed both on said coil base and on said coil winding frame in such a manner that said protrusions are located at the middle part of said space, thereby to form a gap in said coil at the middle part thereof.
5. A method as claimed in claim 1, in which protru-sions are formed on said coil base in such a manner that said protrusions are located at the middle part of said space so that the stranded wire is pressed and flatted by said protrusions and the coil winding pitch at the middle part of said coil is large than that at any other part thereof.
6. A method as claimed in claim 1, in which protru-sions are formed on said coil winding frame in such a manner that said protrusion are located at the middle part of said space so that the stranded wire is pressed and flatted by said protrusions and the coil winding pitch at the middle part of said coil is larger than at any other part thereof.
7. A method as claimed in claim 1, in which protru-sions are formed both on said coil base and on said coil winding frame in such a manner that said protrusions are lacated at the middle part of said apace so that the stranded wire is pressed and flatted by said protrusions and the coil winding pitch at the middle part of said coil is larger than that at any other part thereof.
8. A method as claimed in claim 2, further comprising the steps of:
winding said stranded wire by a first predeter-mined number of turns;
inserting spacers, which are arranged along the same circumference as said protrusions and are rotated in synchronization with the output shaft of said coil machine, in said space after the first winding step; and winding said stranded wire by a second predeter-mined number of turns along said protrusions of said coil base and said spacers in said space after the inserting step, thereby to form a gap in said coil a-t the middle .
part thereof.
winding said stranded wire by a first predeter-mined number of turns;
inserting spacers, which are arranged along the same circumference as said protrusions and are rotated in synchronization with the output shaft of said coil machine, in said space after the first winding step; and winding said stranded wire by a second predeter-mined number of turns along said protrusions of said coil base and said spacers in said space after the inserting step, thereby to form a gap in said coil a-t the middle .
part thereof.
9. A method as claimed in claim 3, further comprising the steps of:
winding said stranded wire by a first predeter-mined number of turns;
inserting spacers, which are arranged along the same circumference as said protrusions and are rotated in synchronization with the output shaft of said coil winding machine, in said space after the first winding step; and winding said stranded wire by a second predeter-mined number of turns along said protrusions of said coil winding frame and said spacers in said space, thereby to form a gap in said coil at the middle part thereof.
winding said stranded wire by a first predeter-mined number of turns;
inserting spacers, which are arranged along the same circumference as said protrusions and are rotated in synchronization with the output shaft of said coil winding machine, in said space after the first winding step; and winding said stranded wire by a second predeter-mined number of turns along said protrusions of said coil winding frame and said spacers in said space, thereby to form a gap in said coil at the middle part thereof.
10. A method as claimed in claim 4, further comprising the steps of:
winding said stranded wire by a first predeter-mined number of turns;
inserting spacers, which are arranged along the same circumference as said protrusions and are rotated in synchronization with the output shaft of said coil winding machine, in said space after the first winding step; and winding said stranded wire by a second predeter-mined number of turns along said protrusions of said coil winding frame and said coil base and said spacers in said space, thereby to form a gap in said coil at the middle part thereof.
winding said stranded wire by a first predeter-mined number of turns;
inserting spacers, which are arranged along the same circumference as said protrusions and are rotated in synchronization with the output shaft of said coil winding machine, in said space after the first winding step; and winding said stranded wire by a second predeter-mined number of turns along said protrusions of said coil winding frame and said coil base and said spacers in said space, thereby to form a gap in said coil at the middle part thereof.
11. A method as claimed in claim 1, 2 or 3, in which said stranded wire has a stranding pitch which is more than twenty times as large as the outside diameter of said stranded wire.
12. A method as claimed in claim 1, in which said stranded wire is made up of a plurality of enameled wires.
13. A coil assembly manufactured according to the method as claimed in claim 1, comprising:
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally in such a manner that a gap is formed in said coil at the middle part thereof, said coil base having protrusions at the portion corresponding to said gap in said coil.
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally in such a manner that a gap is formed in said coil at the middle part thereof, said coil base having protrusions at the portion corresponding to said gap in said coil.
14. A coil assembly manufactured according to the method as claimed in claim 1, comprising:
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally, said coil base having protrusions formed on the surface on which said coil is formed, in such a manner that, when said coil is formed on said coil base said protrusions confront with the middle part of said coil which are located between the outer and inner part of said coil, whereby, at the middle part of said coil, said wire is flattened when compared with that at any other part of said coil, so that the middle part of said coil is larger in coil winding pitch than any other part of said coil
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally, said coil base having protrusions formed on the surface on which said coil is formed, in such a manner that, when said coil is formed on said coil base said protrusions confront with the middle part of said coil which are located between the outer and inner part of said coil, whereby, at the middle part of said coil, said wire is flattened when compared with that at any other part of said coil, so that the middle part of said coil is larger in coil winding pitch than any other part of said coil
15. A A coil assembly manufactured according to the method as claimed in claim l, comprising:
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally in such a manner that, at the middle part of said coil, said wire is flattened when compared with that at any other part of said coil, so that the middle part of said coil is larger in coil winding pitch and smaller in thickness than any other part of said coil.
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally in such a manner that, at the middle part of said coil, said wire is flattened when compared with that at any other part of said coil, so that the middle part of said coil is larger in coil winding pitch and smaller in thickness than any other part of said coil.
16. A coil assembly manufactured according to the method as claimed in claim 1, comprising:
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally, said coil being secured to said coil base with impregnating varnish of epoxy or polyester, and having both end portions which are applied with varnish shorter in hardening time and/or low in fluidity than said impregnating varnish so as to prevent the permeation of said impregnating varnish thereinto thereby to provide flexible lead wires.
a flat shaped coil support base; and a coil formed on said coil base by winding a stranded wire spirally, said coil being secured to said coil base with impregnating varnish of epoxy or polyester, and having both end portions which are applied with varnish shorter in hardening time and/or low in fluidity than said impregnating varnish so as to prevent the permeation of said impregnating varnish thereinto thereby to provide flexible lead wires.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP275583/85 | 1985-12-07 | ||
| JP60275583A JPS62136787A (en) | 1985-12-07 | 1985-12-07 | Electromagnetic cooker coil and manufacture of the same |
| JP2627/86 | 1986-01-08 | ||
| JP262786A JPH0746632B2 (en) | 1986-01-08 | 1986-01-08 | Heating coil for electromagnetic cooker |
| JP28135986A JPS63133486A (en) | 1986-11-25 | 1986-11-25 | Manufacture of heating coil for electromagnetic cooker |
| JP281359/86 | 1986-11-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1257668A true CA1257668A (en) | 1989-07-18 |
Family
ID=27275444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000524667A Expired CA1257668A (en) | 1985-12-07 | 1986-12-05 | Heating coil assembly for an electromagnetic induction cooking heater and method for the same manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1257668A (en) |
-
1986
- 1986-12-05 CA CA000524667A patent/CA1257668A/en not_active Expired
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| Date | Code | Title | Description |
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| MKEX | Expiry |