JPH04162390A - Heating plate manufacturing method and heating plate - Google Patents

Abstract

PURPOSE:To eliminate necessity for both correction after brazing and inspection difficult for visual inspection by providing an aluminum metal plate and a stainless steel sheathed heater left as previously deformed in a shape, in which a heat shrinkage difference therebetween is absorbed, and integrally forming both the plate and heater brazed. CONSTITUTION:A metal plate 1 is formed of aluminum or its alloy so as to present almost a rectangular shape from three sides 2 to 4 and a circular arc part 5. Since the plate 1 is shaped with the sides 3, 4 longer than the other side 2, heat shrinkage amount of the sides 3, 4 is also larger than the side 2. Before a sheathed heater 20 is brazed, the sides 3, 4 are deformed so as to become convex downward. The sheathed heater 20 is also provided with a curved part 23 but deformed as a whole similarly to the plate 1. The plate 1 and the sheathed heater 20 are deformed in an opposite direction to a shrinkage direction previously before brazing, integrally formed and brazed in a furnace. In this way, necessity for both correction of tapping by a hammer and inspection is eliminated without generating a warp and deflection in a heating plate.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention is a metal plate made of aluminum or an alloy thereof, and a sheathed heater of a predetermined length sheathed with rust-proof steel. Particular limitations regarding a method of manufacturing a heating plate by brazing, and a heating plate consisting of a metal plate made of aluminum or its alloy and a sheathed heater of a predetermined length sheathed with rust-free steel. However, the present invention relates to a method of manufacturing a heating plate suitable for use in a vending machine, and a heating plate suitable for use in a vending machine.

"Prior Art" Various heating plates or hot plates formed from a metal plate and a heating heater have been proposed in the past. A typical example of the prior art of the present invention is shown in FIG.

This heating plate is formed from a substantially semicircular plate 31 made of aluminum or an alloy thereof, and a sheathed heater 32 fixed to the surface thereof by brazing. As is well known, the sheathed heater is composed of a heating element 33 that electrically generates heat, an insulator that insulates the heating element, and a rust-free steel 34 that covers the insulator.

Therefore, when the sheathed heater is energized, its heat is transferred to the plate 31 by radiation, and most of the heat is transferred to the plate by conduction via the joint portion that is brazed in a wire from rust-free steel. It turns out.

Various methods have been proposed for attaching the heating element to the metal plate other than brazing, but the linear heating element is fixed to the metal foil using a folded piece, that is, a folded piece formed by cutting and bending a part of the metal foil. A heating plate configured to do so has also been proposed, for example, in Japanese Utility Model Publication No. 46-37176.

Furthermore, Japanese Patent Publication No. 50-25176 proposes a heating mat in which a serpentine heating element is fixed to a metal belt at various locations by welding or mounting fittings.

"Problems to be Solved by the Invention" The above-mentioned heating plate shown in FIG.
2 is made of rust-free steel, it has excellent corrosion resistance, and since the sheathed heater is integrated with the plate 31 by wire contact brazing, it has the characteristics of good heat conduction from the sheathed heater to the plate. We are prepared. Also, unlike welding, it has the advantage of being relatively cheaper to manufacture than brazing.

However, there are some problems. For example, the melting point of Al-3i alloy, which is a brazing material for boat fishing, is 520 to 630 degrees C, so the hard brazing temperature, that is, the brazing temperature, is 55
It has a relatively high melting point of 0 to 650 degrees Celsius, and has the disadvantage that the heating plate warps or bends when brazed. In other words, the expansion coefficient of the plate made of metal such as aluminum is larger than that of a sheathed heater made of rust-free steel.
When the amount of expansion is large and the temperature is lowered to room temperature, the amount of contraction is also large, so in the brazed heating plate, the plate 31 that has a larger amount of contraction is located on the inside with a smaller radius. As shown in Figure 9, it has the disadvantage of warping or bending.

Warped heating plates as described above have low commercial value, so it is necessary to physically correct them by hitting them with a hammer, but this increases the number of man-hours and manufacturing costs. There is a drawback. In addition, when straightening is performed, the strength of the alloy layer at the joint between aluminum and rust-free steel is inferior to that of aluminum or rust-free steel, so cracks, cracks, etc. may occur in this portion. Therefore, an inspection process is required, but another problem arises in that cracks are difficult to visually inspect and the inspection itself is difficult to perform completely.

Further, as shown in FIG. 8, the sheathed heater 32
The terminals must protrude upward or sideways from the plate 31 in order to be connected to the power supply, but when an external force is applied to the protruding portion during handling and transportation, a moment is generated at the joint. This may cause cracks to occur in the joints.

In the heating plate disclosed in the above-mentioned Japanese Utility Model Publication No. 46-37176, the serpentine portion of the linear heating body is fixed to the metal foil with a folded piece, so it does not come off and is protected against electrical accidents. It has the advantage of being safe. However, the heating element is simply fixed to the metal foil with a folded piece and is not integrated by welding or brazing, so the heat transfer from the heating element to the metal foil is mainly through radiation. However, most of the heat may escape into the atmosphere without being transferred to the metal foil.

Furthermore, although the sheathed heater of the above-mentioned heating mat is fixed to the metal belt by welding, the welding points are spot welded, so the heat transfer from the sheathed heater to the metal belt is due to radiation. The disadvantage is that the amount of heat conducted through the welding point is extremely small, and most of the heat generated by the sheathed heater escapes into the atmosphere. Further, although the material of the metal belt of the heating mat and the material of the sheath of the sheathed heater are not specified, if these materials are different, it is generally difficult to weld dissimilar materials, which also has the disadvantage of increasing manufacturing costs. However, since the above-mentioned sheathed heater is fixed to metal healds in some places, the welding line is short and cost is less of a problem.
Furthermore, even if the heat escapes into the atmosphere, there is no particular problem because the escaped heat heats the room.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a heating plate and a heating plate that solve the drawbacks of the conventional heating plate manufacturing method or heating mat as described above. In other words, the invention related to the manufacturing method uses a plate made of aluminum or its alloy with good heat conduction, and a sheathed heater made of rust-free steel with excellent corrosion resistance, which is a different metal from the plate, and the manufacturing cost is low. Moreover, despite using a manufacturing method that integrates the plate and sheathed heater with good heat conduction by brazing, it still requires a physical correction process after brazing and an inspection process that makes visual inspection difficult. The purpose of the present invention is to provide a method for manufacturing a heating plate that does not require heating.

In addition, the invention related to the heating element is such that the brazed joint between the plate made of aluminum or its alloy with good heat conduction and the sheathed heater made of rust-free steel with excellent corrosion resistance is strong;
The object of the present invention is to provide a heating plate that does not cause cracks or cracks in this part even if a physical external force is applied, and therefore does not require inspection for cracks or the like.

"Means for Solving the Problems" In order to achieve the above-mentioned object, the present invention relating to a manufacturing method provides a metal plate made of aluminum or an alloy thereof, sheathed with a predetermined length of rust-proof steel. When linearly brazing the heater, the plate and sheathed heater are deformed in advance into a shape that absorbs the difference in heat shrinkage caused by the difference in their materials, and the two are brazed into one piece. configured.

In addition, the invention according to claim 2 provides a method for linearly brazing and fixing a sheathed heater of a predetermined length sheathed with rust-free steel to a metal plate made of aluminum or its alloy. The heater and the heater are deformed in advance into a shape that absorbs the difference in heat shrinkage caused by the difference in materials, and are fixed with at least one fixing means, and this fixed part is also brazed to integrate the two. configured to do so.

The invention relating to a heating plate according to claim 3 is made up of a metal plate made of aluminum or an alloy thereof, and a sheathed heater of a predetermined length sheathed with rust-free steel, and the sheathed heater has a solder attached to the plate. It is fixed in a linear manner by attaching it, and is also fixed by at least one fixing means, and the fixed portion is also configured to be brazed.

"Operation" Since the invention related to the heating plate is configured as described above, when the sheathed heater is energized, the heating element of the heater generates heat. The heat is also transferred by radiation, but most of the heat is transferred by thermal conduction to the plate made of aluminum or its alloy through the sheath and brazed portion made of rust-free steel.

Therefore, the object to be heated is heated to a predetermined temperature over a wide range by this plate.

According to the present invention, even if physical force is applied to the heating plate during such heating operations, during installation and transportation of the heating plate, or during manufacturing, the sheathed heater can be secured to the plate by at least one fixing means. Since this fixed part is also brazed, there will be no cracks or cracks in the joint between the plate and the sheathed heater. Furthermore, since the portion where the fixing means is provided is also brazed, heat is transmitted to the plate through conduction from this portion as well.

``Example'' This book can be implemented in various ways. For example, after deforming the plate and the sheathed heater into shapes that can absorb the difference in thermal contraction caused by the difference in their materials, and fixing the sheathed heater to the plate using a fixing means,
These can also be fixed together by brazing. The fixing means at this time can be formed by deforming a part of the plate, or can be formed from a separate part. However, these variant embodiments, as well as other combined embodiments, are not explained individually.

First, an embodiment of the manufacturing method will be explained with reference to FIG. The metal plate 1 according to this embodiment is made of aluminum or its alloy, which has excellent thermal conductivity and corrosion resistance, and is formed into a substantially rectangular shape with three sides 2.3.4 and one arcuate portion 5. There is.

Since the side 3.4 of the plate is longer than the other side 2, the amount of heat shrinkage is greater on the side 3.4.

Therefore, in this embodiment, before brazing the sheathed heater, the side 3.4 side is convexed downward in the figure.
For example, it is deformed at the same time as it is cut using a press. The amount of deformation at this time can be determined by calculation or experiment depending on the thermal elongation of the plate 1, the soldering temperature, the size of the plate, etc., but in this example, specific numerical values are determined. It is not shown.

As is well known, the sheathed heater 20 has a heating element 21 in the center.
A sheath 22 made of rust-free steel is coated on the outside with an insulator interposed therebetween. And this sheathed heater 20
The plate 1 also has a curved portion 23, but is deformed in the same way as the plate 1 as a whole. Therefore, when a sheathed heater is placed on the top surface of the plate 1, the sheathed heater comes into line contact with the plate.

As described above, the plate 1 and the sheathed heater 2° are deformed in advance in a direction opposite to the direction of shrinkage before brazing, and then brazed together in a furnace.

For brazing, a well-known method for brazing aluminum or aluminum alloy can be applied. For example, a soft brazing method in which the melting point of the brazing material is relatively low, a hard brazing method in which the melting point is high, or even a brazing method in between can be applied. In these brazing methods, an Al-3i alloy is used as a brazing material for hard brazing, and a Zn alloy is used as a brazing material for intermediate brazing, and a protective component higher in the potential series than AI is used as a brazing material. It is possible to use a flux in which a chloride of a metal belonging to the present invention, a chloride belonging to a lower level in the potential series according to AI as a precipitated metal component, and a fluoride as a purifying component are appropriately blended.

However, the brazing method uses a fluoride flux, as disclosed in the method of brazing aluminum and stainless steel proposed by the applicant, ie, Japanese Patent Application Laid-Open No. 63-93471. It is desirable to do so. Fluoride-based flux, unlike chloride-based flux, leaves a non-corrosive residue after brazing, so there is no need to wash and remove the flux residue after brazing, making the series of brazing operations easier. Because it will be.

In addition, fluoride fluxes are excellent in destroying oxides on the surface of joints, promoting wetting and spreading of brazing filler metal, etc.
This is because a stable and strong brazed joint with a uniform fillet can be obtained.

Next, a method of brazing using a brazing material, flux, etc. having the properties and components described above will be explained. First, flux is applied to the surface of the plate 1 deformed as described above, on which the sheathed heater 2o is placed, and then the sheathed heater is placed on top of the flux, and a brazing material is set in the vicinity thereof. When performing hard brazing or brazing, brazing is performed in a furnace for 550 to 6506 (4'3 to 30 minutes).

During the above brazing, plate 1 expands due to heat,
Since the aluminum plate is deformed in the opposite direction to the contraction direction, when the temperature drops after brazing, the aluminum plate will shrink more than the sheathed heater 20, so it will be shorter than the sheathed heater 20. In other words, it has a flat plate shape.

At this time, even if it does not become flat as calculated, the amount of warpage is small, so the amount of correction is also small, and cracks etc. do not occur as in the conventional case.

Next, in this embodiment, in which examples of the heating plate will be explained with reference to FIGS. 2 to 7, the materials of the plate 1 and the sheathed heater 20,
Since the external shape is the same as that shown in FIG. 1, the same reference numerals will be used and the description will be omitted.

According to the embodiment shown in FIGS. 2 to 5, the plate has 10 sides and 2
Two insertion holes 10.10 are formed at the ends of the plate, and one locking piece 11 is formed near the arcuate portion 5 by cutting and raising a portion of the plate. That is, the insertion hole 10
As shown in FIG. 5, a cut 12 is made parallel to the side 2 at a predetermined interval, and the gap between the side 2 and the cut 12 is deformed upward to form a seed. A hole large enough to insert the heater 20 is formed, and the locking piece 11 is formed by making a U-shaped cut line 13 in the plate and raising it upward in the same way.

According to this embodiment, if the sheathed heater 20 is curved as shown in FIG. 2, both ends thereof are passed through the insertion holes 10.10. Then, the curved portion 23 is fitted into the locking piece 11. At this time, the insertion hole 10.10 is
and the locking piece 11 may be pressed and crushed to some extent. After the sheathed heater 20 is fixed to the plate 1 in this way, the insertion hole and the locking piece are also brazed at the same time as described above. The brazed state is shown in FIG.

According to this embodiment, the sheathed heater 20 is brazed to the plate 1, and the insertion hole 10.10 and the locking piece 1
1 is fixed, so even if the heating plate is forcibly deformed or a moment is applied to the sheathed heater, there is little risk of cracks or the like appearing in the brazed portion.

Another embodiment of the invention is shown in Figure 6.7.

In the examples shown in FIGS. 2 to 5, the insertion hole and the locking piece are formed by deforming a part of the plate, but in this embodiment, the locking metal fitting 14 is formed separately. In other words, the locking fitting 1
4 is formed from a semicircular arc portion 15 that holds the sheathed heater 20, and portions 16 and 16 located on both sides of this arc portion and in contact with the surface of the plate 1, and the inner surface thereof is a brazing surface.

Therefore, prepare a plurality of such locking metal fittings 14, place the sheathed heater 20 at a predetermined position on the plate 1, set the locking metal fittings 14 at the appropriate position of the sheathed heater, and proceed as described above. can be attached.

Also in this embodiment, since the sheathed heater 20 is brazed to the plate 1 and also fixed by the locking fittings 14 and 4, the same effects as in the above-mentioned embodiments can be obtained. According to this embodiment, since the locking fitting is separate from the plate, it is advantageous in terms of manufacturing cost.

"Effects of the Invention" As described above, according to the invention of this method, when brazing the plate and the sheathed heater, the plate is deformed in advance into a shape that absorbs the difference in heat shrinkage caused by the difference in their materials. Since both are integrated by brazing, the manufactured heating plate will not warp or bend. Even if it does warp, the amount of warp is small. Therefore, as before,
The process of hammering and straightening and the costly inspection process are no longer necessary, and the heating plate can be manufactured at low cost.

According to the second aspect of the invention, the plate and the sheathed heater are deformed in advance into shapes that absorb the difference in thermal contraction caused by the difference in their materials, and at least one
The sheathed heater is fixed with more than one fixing means, and the fixed part is also brazed to integrate the two, so in addition to the above effects, even if physical force is applied to the sheathed heater, the brazed part will not crack. The unique effect of the present invention is that no cracks or the like occur.

Furthermore, according to the invention of the heating plate, the sheathed heater is linearly fixed to the plate by brazing and is also fixed by at least one fixing means, and this fixed part is also brazed, so that Even if physical force is applied to the heating plate or the sheathed heater for correction or the like, racks, cracks, etc. do not occur in the brazed parts. Further, even if cracks occur, the amount of cracks or the number of cracks is small and the functionality and commercial value will not be reduced.

[Brief explanation of drawings]

1 to 7 show embodiments of the present invention, FIG. 1 is a perspective view showing an embodiment of the invention relating to a manufacturing method, FIG. Figure 3 is a side view taken along arrow A-A in Figure 2, Figures 4 and 5 are enlarged perspective views of portions B and C in Figure 2, respectively, and Figure 6 shows another embodiment of the fixing means. 7 is a perspective view showing the state in which the heating plate is used, FIG. 8 is a perspective view showing an example of a conventional heating plate, and FIG. 9 is a side view showing the heating plate in a warped state. 11. Metal plate 119. Locking piece 128. Insertion hole 141. Locking metal fitting 209. sheathed heater

Claims (3)

[Claims] (1) In linearly brazing and fixing a sheathed heater of a predetermined length sheathed with rust-free steel to a metal plate made of aluminum or its alloy, the plate and the sheathed heater are made of these materials. A method of manufacturing a heating plate, characterized in that the heating plate is deformed in advance into a shape that absorbs the difference in heat shrinkage caused by the difference in temperature, and then the two are integrated by brazing. (2) When linearly brazing and fixing a sheathed heater of a predetermined length sheathed with rust-free steel to a metal plate made of aluminum or its alloy, the plate and sheathed heater are made of these materials. It is characterized in that it is deformed in advance into a shape that absorbs the difference in heat shrinkage caused by the difference in temperature, is fixed with at least one fixing means, and this fixed part is also brazed to integrate the two. Method of manufacturing a heating plate. (3) Consisting of a metal plate made of aluminum or its alloy and a sheathed heater of a predetermined length sheathed with rust-free steel, the sheathed heater is linearly fixed to the plate by brazing. 1. A heating plate characterized in that the heating plate is fixed with at least one fixing means, and the fixed portion is also brazed.