JPS6142311Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a high-frequency induction heating coil, and more specifically, the present invention relates to a high-frequency induction heating coil for inductively heating a portion of the heated body that contacts or opposes the end face by pressing the end face against the heated part and applying electricity. Regarding induction heating coils.

Thermal bonding (including heat fusion) to the flange of metal cans
When thermally bonding the lid of a flange, the thermal bonding is normally performed using a heat bar or the like at a substantially uniform temperature along the entire length of the flange. In this case, if the heating temperature is high, the thermal bond will become too strong and it will be difficult or impossible to remove the lid, while if the heating temperature is low, the adhesive strength will be insufficient and it will not be susceptible to shocks such as when the can is dropped. There is a risk that the lid may come off due to the internal pressure generated. When thermal bonding is performed by heating to a substantially uniform temperature over the entire length of the flange portion, a problem arises in that the appropriate range of thermal bonding conditions is narrow. In such cases, if relatively strong thermally bonded parts and relatively weak thermally bonded parts (however, the airtightness of the thermally bonded parts was ensured) can be formed alternately, thermally bonded parts can be thermally bonded under a relatively wide range of thermal bonding conditions. There is an advantage that the above-mentioned troubles are unlikely to occur even if this is done. In addition, one of the inventors of this invention previously applied for a patent application in 1983.
In the case of a pull-tab type easy-to-open metal lid in which a lining piece with a through hole is thermally bonded as proposed in No. 173308, the thermal bonding is perforated to form alternating thermally bonded and non-thermal bonded areas. It is possible to achieve the intended purpose even if you do as instructed.

The present invention solves the above-mentioned conventional technical problem, that is, a loop-shaped (herein, a rectangular or elliptical shape other than circular (We will call it a loop shape, including cases of shapes and other shapes)
The purpose of the present invention is to provide a heating temperature at which it is possible to form a thermally bonded portion or a loop-shaped thermally bonded band in which thermally bonded portions and non-thermal bonded portions are alternately provided in a short time.

Another object of the present invention is to provide a heating temperature that can alternately form strongly heated parts and weakly heated parts, or heated parts and non-heated parts, in a short time in a loop-shaped portion of a metal plate.

In order to achieve the above object, the present invention includes a coil having at least one turn in which a plurality of convex portions and concave portions are alternately formed on the surface facing the heated portion, and a heat-resistant elastic thin film fixed to the end face of the convex portion. The present invention provides a high-frequency induction heating coil characterized in that a surface formed by an end surface of the convex portion has a shape substantially corresponding to the heated portion.

The present invention will be described below with reference to the drawings which are examples.

In FIGS. 1, 2, and 3, reference numeral 1 denotes a high-frequency induction heating coil (hereinafter abbreviated as heating coil), which includes a one-turn coil 2 and a heat-resistant elastic thin film 3 (such as a silicone rubber film). (hereinafter abbreviated as elastic thin film). Although the coil 2 has an annular shape in FIG. 1, it may have a rectangular shape or any other arbitrary shape. The coil 2 is made of a nonmagnetic electrically conductive material such as copper, and has a plurality of convex portions 4 and concave portions 5 alternately formed on one end face thereof. The recess 5 is preferably filled with a heat-resistant, electrically insulating, and rigid material 6 (for example, epoxy resin, hereinafter referred to as rigid material). This is because if the concave portion 5 is a gap, the elastic thin film 3 is likely to be damaged by the corner portion 4a of the convex portion 4 when the heating coil 1 is pressed against the object to be heated. The end surface 4b of the convex portion 4 and the end surface 6a of the rigid material 6
The surface formed by is a continuous surface, and the heated surface of the heated portion (for example, the upper surface 7a of the flange portion 7 in FIG. 4 or the upper surface 8a of the curled portion 8 in FIG. 5) It has a substantially corresponding shape, and the convex portion 4
The heated portion facing the heating portion is configured to be substantially uniformly and satisfactorily inductively heated. The elastic thin film 3 is fixed to the end surface 4b of the convex portion 4 and the end surface 6a of the rigid material in order to apply a substantially uniform pressing force when pressing the heating coil 1 against the heated part. The thickness is preferably about 0.5 to 4.0 mm. If it is thinner than about 0.5 mm, the above-mentioned substantially uniform pressing force will not be ensured when the heated surface has some irregularities, while if it is thicker than about 4.0 mm, the end face 4b and the heated surface (for example, the flange part) will not be secured. Top surface 7a)
This is because if the distance between the two ends becomes too large, the electromagnetic coupling will weaken and satisfactory induction heating will not be achieved. Since the elastic thin film 3 has an appropriate thickness, in the case shown in FIG. 5, there is no problem even if the end surfaces 4b and 6a are made substantially flat, since a substantially uniform pressing force is ensured.

Inside the coil 1, a magnetic core 10 made of a high magnetic permeability material (for example, ferrite) is attached via an electrically insulating sheet 9 (for example, a glass wool sheet) to enhance the electromagnetic induction effect. Further, an electric insulator 11 is provided between the feeders 12 facing each other. The feeder 12 is connected to a high frequency oscillator (not shown).

Figure 4 shows a metal can 1 using the above heating coil 1.
This figure shows an example in which the lid part 14 having the heat-adhesive layer 14a is thermally bonded to the flange part 7 of No. 3. The lid part 14 is placed on the flange part 7a with the thermal adhesive layer 14a facing downward, and the heating coil 1 is placed on the lid part 14 with the end surface 4b of the convex part facing the flange part 7a. place the heating coil 1 on the pressing body 15
(The portion 15a in contact with the upper surface of the heating coil 1 needs to be made of an electrically insulating rigid body so that the pressing body 15 is not heated by induction.) By pressing the flange portion 15a and applying electricity, the flange portion 7 are rapidly heated by induction to form a thermal bond. At this time, the shallower the recess 5, the smaller the heating temperature difference between the portion of the flange 7 facing the recess 5 and the portion of the flange 7 facing the protrusion 4, and therefore the smaller the difference in thermal adhesive strength. On the other hand, the deeper the recess 5, the larger the difference in heating temperature between the two parts, and the larger the difference in thermal adhesive strength.If the recess 5 becomes too deep, the part of the flange 7 facing the recess 5 will not be thermally bonded. Therefore, depending on the thermal adhesive strength required for the lid 14, the depth of the recess 5 (approximately 0.3 to 2 mm) and the circumferential length of the protrusion 4 and recess 5 (approximately 2 to 10 mm each) are determined. By determining this, it becomes possible to thermally bond the lid part 14 to the flange part 7 in such a way that it is relatively easy to peel off when pulling up the knob part 7b to open the package, and it is difficult to peel off due to internal pressure. . Although not shown, a cooling pipe (which also serves to adjust the temperature of the coil 2) may be provided along the outer periphery of the coil 2 if necessary.
However, in the case of thermal bonding, etc., the thermal efficiency is better when the temperature of coil 2 is higher to a certain extent, so
It is preferable not to cool the

6, 7, 8, and 9 show heating coils 21 of other embodiments of the present invention. Parts with the same reference numerals as in FIGS. 1 and 2 indicate the same parts or parts with the same function. The main difference between the heating coil 21 and the heating coil 1 is the current feeding method. That is, a conductor bundle 24 consisting of a thin insulated conductor wire 23 having many turns (for example, 100 turns) is provided along the inside of the coil 22, and the conductor wire 23 passes through the hole 25 of the coil 22 to the outside of the coil 22. It is connected to a high frequency oscillator (not shown). When the conducting wire bundle 24 is energized, a high frequency oscillation current flows along the convex portion 4 of the coil 22 due to the electromagnetic induction effect, and the heated portion can be heated by induction in the same manner as described above. In the case of the heating coil 1 shown in Fig. 1, the part of the coil 2 that faces the discontinuous part 2a is difficult to heat, but in the case of the heating coil 21, there is no such discontinuous part, so the temperature is averaged along the entire circumference. It has the advantage of being able to perform heating. Furthermore, in the case of the heating coil 1, an expensive current transformer (not shown) is required for impedance matching, but in the case of the heating coil 21, the impedance can be adjusted, so it is suitable for semiconductor high-frequency oscillators. , it also has the advantage of not requiring a current transformer.

10 and 11 show a heating coil 31 according to still another embodiment of the present invention, in which the coil 32 is flat and thin (preferably 0.05 to 0.05 mm thick).
It is formed by tightly winding a ribbon (preferably about 5 to 20 mm wide) of a metal with high electrical conductivity such as copper in multiple layers (at least 10 turns), although not shown in the figure. A major difference from the coil 2 described above is that the space between the coils is electrically insulated by a heat-resistant insulating coating (made of polyimide resin, for example). 33 is an elastic thin film, 34 is a convex portion, 35 is a concave portion, 36 is an electrically insulating rigid material that fills the concave portion, 38 is a magnetic core, 39 is a cooling mantle, and 39a is a conduit for causing the cooling liquid to flow through the cooling mantle. , 40 is a feeder for feeding a high frequency current to the coil 2, and 41 is a support (made of Bakelite, for example) fixed to the magnetic core 38, and is connected to a pressing mechanism (not shown).

In the case of a multilayer coil (number of turns n), the impedance is approximately n ₂ times that of a one-turn coil. Therefore, if the output is the same, the voltage can be increased and the supplied current can be made smaller. Therefore, the module loss due to the feeder is reduced, and when using a semiconductor high-frequency oscillator, there is no need to use an expensive current transformer for impedance matching. Therefore, power loss due to the current transformer can be prevented, and overall heating efficiency is improved. It has the advantage of improving

The high-frequency induction heating coil of the present invention includes at least one turn of the coil in which a plurality of convex portions and concave portions are alternately formed on the surface facing the heated portion, so that the coil can be heated along the loop-shaped heated portion. This has the effect that high-frequency induction heating can alternately form strongly heated parts and weakly heated parts, or heated parts and non-heated parts, in a very short time. Further, since the heat-resistant elastic thin film is fixed to the end face of the convex portion, it is possible to apply a substantially uniform pressing force due to the buffering effect of the elastic coating.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the heating coil of the first embodiment of the present invention, Fig. 2 is a front view of the heating coil of Fig. 1, Fig. 3 is a longitudinal sectional view taken along the line - in Fig. The figure is a partially cutaway front view to show an example of how to use the heating coil in Fig. 1, Fig. 5 is a longitudinal cross-sectional view to show an example of the shape of the convex end face of the heating coil in Fig.
The figure is a plan view of a heating coil according to the second embodiment of the present invention, and FIG. 7 is a side view taken from the - line in FIG.
Figure 8 is a longitudinal sectional view taken along the - line in Figure 6;
The figure is a cross-sectional view taken along the - line in FIG. 8, FIG. 10 is a longitudinal cross-sectional view of a heating coil according to the third embodiment of the present invention, and FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. It is a diagram. 1, 21, 31...high frequency induction heating coil,
2, 22, 32... Coil, 3, 33... Heat-resistant elastic thin film, 4, 34... Convex portion, 4b... End surface,
5, 35... Recessed portion, 7... Flange portion (heated portion), 8... Curled portion (heated portion).

Claims (1)

[Scope of utility model registration request] A coil having at least one turn in which a plurality of convex portions and concave portions are alternately formed on the surface facing the heated portion, and a heat-resistant elastic thin film fixed to the end surface of the convex portion, A high-frequency induction heating coil characterized in that the thus formed surface has a shape that substantially corresponds to the heated portion.