JPH11309723A - Method and apparatus for electromagnetic induction heating of laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for electromagnetic induction heating of a laminate which curtails the vulcanization time of the laminate remarkably to improve production efficiency and reduces the temperature difference between the outer part and inner part of the laminate during heating to make the quality uniform and to improve the quality as a whole. SOLUTION: In a method for electromagnetic induction-heating an unvulcanized rubber layer by a method in which lines of magnetic force generated by passing alternating current through electromagnetic induction coils 3 arranged around a cylindrical laminate A in which circular thin steel plates and circular unvulcanized rubber layers are laminated alternately are made to penetrate the steel plates of the laminate A perpendicularly so that eddy current is passed through the steel plates to make them emit heat, a central part opening (a) penetrating vertically is formed in advance in the central shaft part of the laminate A in the coil 3, an outer magnetic path type electromagnetic induction heating device 5 equipped with an electromagnetic induction coil 7 is inserted into the opening (a), and the unvulcanized rubber layers are heated from both inside and outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical or prismatic laminate obtained by alternately laminating a circular or square thin steel plate and a circular or square unvulcanized rubber layer. And the electromagnetic induction heating (In
duction heating (hereinafter also referred to as IH) device.

[0002]

2. Description of the Related Art The above-mentioned electromagnetic induction heating apparatus is generally considered to be superior in safety because it has no heating part as compared with an electric resistance type heater. It is used for cookers and IH rice cookers. For example, in the case of an IH cooking device, usually, an electromagnetic induction coil is wound around a non-magnetic material, and an iron pot or a frying pan made of a magnetic material is placed on a plate as a magnetic flux diffusion member provided on the upper surface thereof. By placing a container such as the above, and applying a voltage to the electromagnetic induction coil from the AC power supply,
Lines of magnetic force are generated by an electromagnetic induction coil, and the lines of magnetic force are diffused by a magnetic flux diffusing member throughout the width of the bottom surface of the container, so that the eddy current flows through the bottom of the container in parallel to generate Joule heat. And an indirect heating method of heating the container itself. In addition, as a prior art of the electromagnetic induction heating device, there are those described in, for example, JP-A-6-208888 and JP-A-8-264272.

[0003] By the way, the circular or square thin steel plate and the circular or square unvulcanized rubber layer are alternately laminated, and the unvulcanized rubber layer is vulcanized to form a cylindrical or prismatic laminate. There are seismic isolation devices, anti-vibration devices, and bearing devices that have a body. These devices are installed at the foundation of buildings and structures, and are mainly used to absorb vibrations during earthquakes and to suppress or prevent vibrations from the ground from being transmitted to buildings and structures. Is done. The height of this type of laminate is 50-500m
m, the outer diameter of the column has various sizes from about 200 mm to 1500 mm, and the outer shape of the prism has various sizes from 200 mm to 2000 mm square. Further, there is a laminate having flanges on the upper and lower sides of the laminate, and the flange is generally large enough to protrude radially outward from the laminate body by about 200 mm.

[0004] When a laminate is formed by alternately laminating a steel sheet and an unvulcanized rubber layer, steam is introduced into the mold under a certain pressure while being housed in the mold, and the temperature is about 20 ° C to 130 ° C. Vulcanization by heating to That is, it is a general vulcanization method that vulcanization of this type of laminated body is performed without preheating from room temperature.

[0005]

However, the conventional heating method and the conventional apparatus for vulcanizing a laminated body such as the above-described seismic isolation apparatus have the following problems. 1) As shown in the temperature diagram of the maximum and minimum temperatures of vulcanization in the case of a laminate having an outer diameter of 1000 mm and a height of 375 mm in FIG. 8, vulcanization is performed by heating from room temperature under a constant pressure. In the method, it takes a long time to complete the vulcanization operation, and the production efficiency is very low.

2) As shown in FIG. 8, the temperature difference between the inside and outside of the laminate (difference between the maximum temperature and the minimum temperature) is large throughout the vulcanization process, causing a significant difference in the progress of the vulcanization operation. In other words, the steam is heated through the mold to the outer surface of the laminate by heat transfer, so that the temperature only near the outer surface rises and it takes a long time for the temperature to rise to the inside,
The quality of the rubber layer of the laminate may be adversely affected.

The present invention has been made in view of the above points, and significantly reduces the time required until the vulcanization of a laminate is completed to improve the production efficiency, and the temperature difference between the inside and outside of the laminate during heating. It is an object of the present invention to provide an electromagnetic induction heating method and an electromagnetic induction heating apparatus for a laminate, which can reduce the size of the laminate to make the quality uniform and improve the overall quality.

[0008]

According to a first aspect of the present invention, there is provided a method for electromagnetically heating a laminated body, comprising the steps of: forming a circular or square thin steel plate and a circular or square unvulcanized rubber layer; The magnetic field lines generated by passing an alternating current through an electromagnetic induction coil disposed around the laminate, the columnar or prismatic laminate obtained by alternately laminating the laminate, and the steel sheets of the laminate are orthogonal to each other. An electromagnetic induction heating method for heating the unvulcanized rubber layer by causing an eddy current to flow through the steel sheet and causing the steel sheet to generate heat by allowing the steel sheet to pass through in a direction, wherein the central axis portion of the laminate in the electromagnetic induction coil includes: A central opening penetrating vertically is provided in advance, and the unvulcanized rubber layer is heated from inside and outside by inserting an outer magnetic path type electromagnetic induction coil into the opening.

According to the electromagnetic induction heating method according to the first aspect of the present invention, the AC voltage is simultaneously applied to the electromagnetic induction coil outside the laminate and the external magnetic path type electromagnetic induction coil inside the center opening. Is applied to cause a current to flow, so that the magnetic lines of force generated inside and outside the laminate are transmitted through the steel sheet so as to be orthogonal to each other. And the eddy current flows through each steel plate by those lines of magnetic force, and Joule heat is generated. Since the strength of the magnetic field line becomes weaker as the distance from the electromagnetic induction coil increases, it is strong near the outer periphery and near the center of the steel sheet, and gradually decreases toward the middle of the steel sheet. Is good, the amount of heat generated at the intermediate position in the radial direction of the steel sheet is lower than the outer peripheral part and the central part, but with heat conduction from the inner and outer periphery to the intermediate part, the steel sheet becomes almost uniformly hot, The unvulcanized rubber layer between the steel plates is also heated almost uniformly.

Therefore, in the method of heating a laminate by electromagnetic induction according to the present invention, unlike the conventional method of housing the laminate in a mold and heating it with steam, the inside (center portion) of the unvulcanized rubber layer is heated. Since the lines of magnetic force are transmitted and heated similarly, the temperature difference between the inside and outside is small, and the quality is greatly improved. Depending on the type of the laminated body, there is a type in which a flange made of a magnetic material such as iron is provided on the upper and lower sides. In this case, particularly, the flange is heated at the same time, and the heat stored in the flange is transmitted to the laminated body. Therefore, the laminate is more uniformly heated.

According to a second aspect of the present invention, there is provided a cylindrical or prismatic laminate obtained by alternately laminating a circular or square thin steel plate and a circular or square unvulcanized rubber layer. The lines of magnetic force generated by passing an alternating current through the electromagnetic induction coil disposed around the perimeter of the laminated body are transmitted through the steel sheet of the laminate in a direction orthogonal to the steel sheet, thereby causing an eddy current to flow through the steel sheet to generate heat, and the unvulcanized rubber layer In the electromagnetic induction heating method of heating the electromagnetic induction coil, in the center axis portion of the laminated body in the electromagnetic induction coil, a center opening that penetrates up and down is provided in advance, and a plug pin-shaped steam type or The unvulcanized rubber layer is heated from inside and outside by inserting a hot water type heating means.

[0012] According to this configuration, similarly to the heating method of the first aspect, since the laminated body can be simultaneously heated from the outer peripheral side and the inner central portion, the steel sheet laminated between the unvulcanized rubber layers. Through the inner and outer peripheral portions, and the unvulcanized rubber layer is heated substantially uniformly.

According to a third aspect of the present invention, after the unvulcanized rubber layer of the laminate is preheated by electromagnetic induction heating, the laminate is inserted into a mold and heated under a constant pressure. Vulcanization is preferred.

According to this configuration, as shown in FIG. 8, when the unvulcanized rubber of the laminate is vulcanized, the laminate is preheated to 100 ° C. or higher, and then the laminate is molded. By performing conventional vulcanization work with steam by inserting
The time required for vulcanization, including the time required for preheating, is greatly reduced to about 1/5 as compared with the conventional method of vulcanizing from normal temperature. Further, since the time required for vulcanization including preheating is reduced, the running cost is reduced, and it is economical.

According to a fourth aspect of the present invention, in the unvulcanized rubber layer of the laminate, a temperature sensor is inserted at each of the upper and lower ends near the outer peripheral surface and at the intermediate position in the radial direction at the upper and lower ends, respectively. After measuring the temperatures of at least the three points at the time of induction heating and controlling the amount of electric power necessary for electromagnetic induction heating so that the highest temperature among them does not exceed the set temperature (for example, thyristor control), before vulcanization Preferably, the temperature sensor is withdrawn from the unvulcanized rubber layer.

Since the size of the laminate is different and the thickness and the number of steel plates and the thickness and the number of unvulcanized rubber layers are different for each size, it is conventionally difficult to heat to an appropriate temperature for each size. However, according to the invention as set forth in claim 4, immediately after the start of heating, the upper and lower ends of the outer peripheral portion have the highest temperature, and the middle position in the radial direction has the lowest temperature. Reference temperature (for example, 1
By controlling the current flowing through the electromagnetic induction coil so that the temperature becomes equal to (00 ° C.), the highest temperature point due to the electromagnetic induction heating can be suppressed below the set reference temperature. In this state, while the electromagnetic induction heating is continued, the temperature at the lowest temperature point rises due to a heat conduction effect via the steel plate or the like and reaches near the reference temperature. When the lowest temperature point reaches the reference temperature, all the points of the unvulcanized rubber layer have reached the reference temperature, so that the unvulcanized rubber layer is heated evenly. According to this method, the unvulcanized rubber layers of the laminates having different sizes and types can be uniformly heated to a predetermined (reference) temperature. In addition, if the unvulcanized rubber layer is completely vulcanized, it will be difficult to remove the temperature sensor (such as a thermocouple), which may damage the rubber layer. It is desirable.

According to a fifth aspect of the present invention, there is provided an electromagnetic induction heating apparatus for carrying out the above method, wherein a circular or square thin steel plate and a circular or square unvulcanized rubber layer are alternately laminated. An electromagnetic induction heating device for heating a body or a prismatic laminate, the electromagnetic induction heating device being provided over substantially the entire outer peripheral surface of a cylindrical case made of a non-magnetic material capable of completely containing the laminate. A coil is wound and connected to an AC power supply, and a center opening that penetrates vertically in the center axis of the laminate is provided in advance, and an external magnetic path type electromagnetic induction coil is inserted into the opening and the inside and outside are inserted. The unvulcanized rubber layer can be heated.

According to the electromagnetic induction heating apparatus of the present invention having the above-described structure, the above-described heating method can be reliably performed, and the structure is simple, and the running cost of heating by steam is considerably reduced. In addition, since the magnetic flux generated from the electromagnetic induction coil passes through the outer peripheral portion and the inner central portion so as to be substantially parallel and perpendicular to the steel plate, the steel plates of the laminated body are simultaneously heated from the inside and outside, and the heating state is maintained. And the heating of the unvulcanized rubber layer is performed more evenly.

According to a sixth aspect of the present invention, there is provided an electromagnetic induction heating apparatus comprising: a cylindrical or prismatic lamination in which a circular or square thin steel plate and a circular or square unvulcanized rubber layer are alternately laminated. An electromagnetic induction heating device for heating a body, wherein an AC power supply is provided by winding an electromagnetic induction coil around substantially the entire outer peripheral surface of a cylindrical case made of a nonmagnetic material capable of completely housing the laminate. And a center opening which penetrates vertically in the center axis of the laminated body, and a plug-pin-shaped steam-type or hot-water-type heating means is inserted into the opening, and the unvulcanized rubber is inserted from inside and outside. The layers can be heated.

In the electromagnetic induction heating apparatus according to the sixth aspect, there is a difference that steam or hot water is used for heating the central portion of the laminate and an AC power source is used only on the outer peripheral side. The operation according to the fifth aspect of the present invention is common in that the unvulcanized rubber layer can be heated substantially uniformly.

According to a seventh aspect of the present invention, an electromagnetic induction coil is wound around substantially the entire outer peripheral surface of the cylindrical case made of a non-magnetic material, and has a predetermined width at the same height as the cylindrical case. Multiple electromagnetic waves (magnetic flux) formed in a prismatic shape by laminating a number of strip-shaped and extremely thin silicon steel sheets
It is desirable to dispose the collecting body on the outer circumference of the electromagnetic induction coil at intervals in the circumferential direction.

According to the seventh aspect of the present invention, the magnetic flux collector made of a thin silicon steel plate has the function of collecting magnetic lines of force generated by the electromagnetic induction coil and directed outward of the case.
Since the prismatic magnetic flux collector formed by laminating thin silicon steel plates hardly generates heat, it works effectively only for collecting magnetic flux (lines of magnetic force). In addition, by providing a prismatic magnetic flux collector made of silicon steel plate, it is possible to omit the case of a non-magnetic material that is usually provided outside the coil to prevent the lines of magnetic force from escaping outward, improving heat dissipation And
Heat generation of the coil when the lines of magnetic force are generated is greatly reduced.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a method for heating a laminate comprising a steel sheet and an unvulcanized rubber layer and an electromagnetic induction heating apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing an example of the electromagnetic induction heating device. FIG. 2 is a side view showing a forming process of the laminate.

As shown in FIG. 1, an electromagnetic induction heating device 1 for preheating a laminated body for a seismic isolation device is integrally mounted on a frame-shaped gantry 11 whose front, rear, left, right, and top surfaces are open. The heating device 1 is made of a cylindrical body having upper and lower ends opened corresponding to the laminated body A for the seismic isolation device. The outer surface of the non-magnetic stainless steel cylindrical case 2 is insulated and coated with an aluminum electromagnetic induction coil of aluminum. 3 is wound from the upper end to the lower end. Further, a cylindrical case 4 made of a nonmagnetic material made of stainless steel is mounted on the outer peripheral side of the coil 3. The inner and outer cases 2 and 4 are cut in the length direction in a part of the circumferential direction to prevent generation of heat due to the generation of eddy current in the circumferential direction of each case 2 and 4, so-called cut 2a (FIG. 5). (see (b)).

In the laminate A, in this embodiment, the lower end of a cylindrical core 31 made of steel (SS) is screwed to the center of a flange F described below, or the center is a space. . As shown in FIG. 2, in the present example, a thin circular steel plate C having a lowermost layer having a central opening c is placed on a flange F, and a thin circular steel plate having a central opening b is placed on the circular steel plate C. The unvulcanized rubber layer B is placed. The circular steel sheets C having the unvulcanized rubber layers B provided on the upper surface are stacked in order, and a laminate A in which the steel sheets C and the unvulcanized rubber layers B are alternately laminated is formed. Further, in this example, iron flanges F, which are magnetic materials, are attached to both upper and lower ends of the laminate A. The flanges F have a size such that they protrude radially outward from the outer peripheral surface of the laminate A. is there. In addition, the flange F is usually a final product while being attached to the upper and lower ends of the laminate A. Some types of the laminate A do not include the flange F.

The laminate A is formed or conveyed on a cart 21. On the cart 21, a pantograph type lifting mechanism 2 which moves up and down by the expansion and contraction of a hydraulic cylinder (not shown).
2 is mounted, and the lower flange F of the stacked body A is mounted and supported on the ring-shaped mounting table 23 at the upper end of the elevating mechanism 22. The stack A is inserted into the heating device 1 by raising the mounting table 23 by the elevating mechanism 22 in a state where the carriage 21 is carried into the center of the gantry 11.

[0028] In the electromagnetic induction heating apparatus 1 ₁ according to a first embodiment of the present invention, as shown in FIG. 4, also the center in the opening a passing through the center portion of the flange F with laminate A in the vertical direction,
A small electromagnetic induction heating device 5 is inserted. This heating device 5 is an electromagnetic induction heating device of an external magnetic path type. An electromagnetic induction coil 7 made of insulating aluminum is wound around the outer peripheral surface of a nonmagnetic stainless steel small-diameter circular tubular case 6 from the upper end to the lower end. The outer peripheral side of the coil 3 is covered with a nonmagnetic stainless steel tubular case 8. The electromagnetic induction heating device 5 has the same structure as the electromagnetic induction heating device _11, and has the same height in this example. Electromagnetic induction coil 3 of heating device 1 ₁
The height of the portion is set to be approximately three times the height of the laminate A in this example, but may be 1.5 times or more.

In this state, by applying a voltage (50 to 60 Hz, 200 V in this example) to the electromagnetic induction coil 3 of the heating device 1 and the electromagnetic induction coil 7 of the heating device 5 at the same time by the AC power supply, An alternating magnetic field (line of magnetic force) that passes through the steel sheet C of the laminate A in the vertical direction is generated from 1.3. FIG. 3 shows the state of generation of magnetic flux when an alternating current is applied only to the heating device 1. In addition, since the height of the portion of the electromagnetic induction coil 3 is set to 1.5 times or more (three times in this embodiment) the height of the laminated body, linearity of the magnetic flux passing through the laminated body is achieved, and a uniform temperature is obtained. As a result, the heat generated by the magnetic flux is maximized. In the case 2, the steel sheets C of the laminate A are positioned in multiple layers in the horizontal direction, and the lines of magnetic force penetrate the steel sheets C so as to be orthogonal to the vertical direction. An eddy current flows through each steel plate C to generate Joule heat. As the strength of the magnetic field lines is increased away from the inner and outer heating devices 1 and 5, in other words, the outer peripheral portion and the central portion of the steel sheet C are stronger, and gradually become weaker from the inner and outer circumferences to the intermediate position in the radial direction. Further, since the steel sheet C is a conductor and has a high thermal conductivity, the amount of heat generated at a radially intermediate position of the steel sheet C is lower than that of the inner and outer peripheral portions.
Heats almost uniformly, so the unvulcanized rubber layer B between the steel sheets C
Is also heated almost uniformly.

Further, since the height of the portion of the electromagnetic induction coil 7 of the inner peripheral side heating device 5 is set to be the same as that of the outer peripheral side heating device 1, the generated magnetic force lines are orthogonal to the steel sheet C. The light is transmitted in parallel with. Therefore, the efficiency (heating efficiency) at which the steel sheet C generates heat by electromagnetic induction when a predetermined AC voltage is applied is high. Furthermore, since the iron flanges F are attached to the upper and lower surfaces of the laminate A, the magnetic flux of electromagnetic induction is concentrated on the flange F, penetrates the laminate A in a direction perpendicular to the laminate A, and vortices the flange F as well. An electric current flows to generate Joule heat, which is stored in the flange F, and the heat is gradually transferred to the laminate A.

FIGS. 5A and 5B show another embodiment of the electromagnetic induction heating apparatus of the present invention. The difference between the heating device 12 of the _second embodiment and the above embodiment is as follows. That is, the height of the inner peripheral side heating device 5 was reduced so as to be the same height as the laminate A, the case 4 outside the heating device 1 was omitted, and instead, the same height as the case 2 was used. A plurality of (for example, eight) magnetic flux (electromagnetic wave) collectors 10 formed by laminating a large number of thin steel plates having a predetermined width to form a prismatic body are wound around the outer peripheral surface of the case 2. That is, prismatic magnetic flux collectors 10 are arranged at equal intervals in the circumferential direction on the outer peripheral surface of the coil 3 for use. Since other structures common to the heating device 1 ₁ of the first embodiment, the same members denoted by the same reference numerals, and description thereof is omitted.

[0032] According to the heating device 1 ₂ of the present embodiment, alternating magnetic field (magnetic field lines) is generated by applying a voltage by the AC power supply to the electromagnetic induction coil 3 and the electromagnetic induction coil 7, out outward of the magnetic force lines Since the lines of magnetic force that diffuse to the outside are collected by the plurality of magnetic flux collectors 10, they are prevented from diffusing outward without the outer case 4. Therefore, the lines of magnetic force function with high efficiency for heating the laminate A, and since there is no case 4 outside the electromagnetic induction coil 3, even if the coil 3 itself generates heat, the heat radiation is good and the coil 3 is not easily heated. The steel sheet C is heated by the magnetic lines of force generated by the heating device 5 and heated not only at the outer peripheral portion but also at the central portion of the laminate A. Further, since the steel sheet C is a conductor and has a high thermal conductivity, the amount of heat generated at a radially intermediate position of the steel sheet C is lower than that of the inner and outer peripheral parts, but the heat amount generated in the middle of the steel sheet C as time passes. Since the position becomes hot almost similarly to the inner and outer peripheral edges, the unvulcanized rubber layer B between the steel plates C is also heated substantially uniformly not only at the outer peripheral edge and the center but also at the intermediate position. Further, since the flanges F made of iron are attached to both the upper and lower surfaces of the laminate A, the magnetic flux of electromagnetic induction is concentrated on the flanges F as in the first embodiment, and penetrates the laminate A in a direction orthogonal thereto. An eddy current also flows to the flange F, generating Joule heat, which is stored in the flange F, and the heat is gradually transferred to the laminate A.

FIG. 6 shows a third embodiment of an electromagnetic induction heating apparatus of the present invention, the heating device 1 ₃ according to the third embodiment
Are different from the first and second embodiments in the following points. That is, the column-shaped steam-heated plug pin 12 is inserted into the center opening a of the laminate A. A steam inlet 12a and a steam outlet 12b are provided at the bottom of the plug pin 12.
And the steam from the steam source is introduced into the plug pin 12 from the inlet 12a via a hose (not shown), and is circulated through the plug pin 12 and discharged from the outlet 12b, thereby forming the laminate A. Heat the inner center. Since other structures common to the heating device 1 _1, 1 ₂ of the above embodiments, the same members denoted by the same reference numerals, and description thereof is omitted.

[0034] According to the heating device 1 ₃ of the present embodiment, alternating magnetic field (magnetic field lines) is generated by applying a voltage by the AC power supply to the electromagnetic induction coil 3, the magnetic field lines laminate A
, In particular, near the outer periphery of the laminate A, and the steam introduced into the plug pins 12 heats the vicinity of the center of the laminate A. Since the steel sheet C is a conductor and has high thermal conductivity, and is heated simultaneously at the outer peripheral part and the central part of the steel sheet C, even if the temperature in the middle part in the radial direction is lower than that of the inner and outer peripheral parts, the steel sheet C is used. Since the temperature of the intermediate portion of the steel sheet C rises to approximately the same temperature as that of the central portion and the outer peripheral portion as time elapses since the heat is transmitted through the uncured rubber layer B between the steel plates C, The heating is substantially uniform not only at the peripheral portion and the central portion but also at the radially intermediate portion. Further, since the flanges F made of iron are attached to both the upper and lower surfaces of the laminate A, the magnetic flux of electromagnetic induction is concentrated on the flanges F as in the first embodiment, and penetrates the laminate A in a direction orthogonal thereto. An eddy current also flows through the flange F to generate Joule heat, which is stored in the flange F, and the heat is gradually transferred to the laminate A. In the case where the temperature rise at the center of the laminate A is too rapid by heating with steam, hot water can be used instead of steam.

[0035] FIG. 7 (a) shows a fourth embodiment of an electromagnetic induction heating apparatus of the present invention, or heating device 1 ₃ of the third embodiment is the electromagnetic induction heating device according to the fourth embodiment the particular change is not the heating device 1 ₂ of the second embodiment. The difference is that the voltage control method of the electromagnetic induction heating device 1 for heating the outer peripheral portion of the laminate A is devised. That is, when the laminate A is laminated by alternately laminating the unvulcanized rubber layer B and the steel sheet C, the thermocouple 15 of the three thermocouples 15, 16, and 17 in this example is placed at the lower end. , The thermocouple 16 is located at a radially intermediate position of the unvulcanized rubber layer B located in the middle in the vertical direction, and the thermocouple 17 is located at the upper end of the unvulcanized rubber layer B. It is inserted and set on the outer peripheral portion of the rubber layer B, respectively. For other configurations, the heating devices ₁₁ to
Since common with 1 _3, the same members denoted by the same reference numerals, and description thereof is omitted.

The heating adjustment of the laminate A when an AC voltage is applied to the electromagnetic induction heating coil 3 of the heating device 1 is most easily heated by the heating device 1 as shown in FIG. The temperature (indicated by a solid line) measured by thermocouples 15 and 17 arranged on the outer peripheral portion where the temperature rises immediately is
To prevent the temperature from reaching a preset temperature t ₁ (for example, 100 ° C.) or more, when the temperature reaches, for example, 100 ° C., the application of the AC voltage is stopped, and when the temperature falls to a predetermined temperature t ₂ (for example, 98 ° C.), the AC voltage is reduced again. Turn on the power to apply
By intermittently controlling turning off or lowering the maximum voltage of the AC voltage to lower the heating capacity of the heating device 1 per unit time as a whole,
It can be performed by a method such as thyristor control that prevents the temperature at the highest temperature position from exceeding a preset temperature (for example, 100 ° C.). As described above, while controlling the highest temperature point in the laminate A to be within the predetermined temperature range, the temperature of the lowest temperature point measured by the thermocouple 16 (indicated by a dotted line) is changed by the heat passing through the steel sheet C. By conduction, it rises as shown in FIG. 7 (b) and reaches near the maximum temperature. In this state, the temperature inside the laminate A is uniformly heated as a whole.

[0037] When the heating device 1 ₄ of the present embodiment, the laminated body A
Also using an electromagnetic induction heating apparatus 5 to a device for heating the inner center portion, i.e. the heating device 1 and the heating device based on the temperature measured by the thermocouple 15, 16, 17 in the heating apparatus 1 ₃ according to the second embodiment It is most effective to control both AC voltages simultaneously. In this case, a thermocouple (not shown) is inserted into the inner peripheral portion together with the radially intermediate position of the unvulcanized rubber layer B located in the middle in the vertical direction, and the heating device 5
It is desirable to be able to measure the state of heating by the method. However, it is needless to say that controlling only the AC voltage of the heating device 1 while heating the inner central portion of the stacked body A with steam or hot water via the plug pins 12 is similarly effective.

Further, the electromagnetic induction heating apparatus 1 of FIG.
When a voltage of 200 V (60 Hz) was applied to the electromagnetic induction coil 3 while a flange F having an outer diameter of 1400 mm was attached to the upper and lower ends of a 75 mm laminate A and a current was passed, the laminate was laminated as shown in FIG. The temperature of the unvulcanized rubber layer B in the body A rose to 100 ° C. or more in about 1/40 of the conventional vulcanization time, and the temperature difference between the outer peripheral portion and the central portion almost disappeared. Then, the preheating step was completed, and vulcanization was performed by steam in a manner basically similar to the conventional method. As a result, the unvulcanized rubber layer B was vulcanized in about 1/5 of the conventional vulcanization time. Was. As a result, the time spent in the preheating / vulcanization step is greatly reduced to about 1/5 compared to the conventional vulcanization time using steam.

Although one example of the electromagnetic induction heating apparatus according to the present invention has been described above, the present invention can be implemented as follows.

A. The laminate A is not limited to a cylinder, but may be a prism. In this case, the shape of the case is changed to the laminate A.
It is formed in a rectangular tube shape corresponding to the shape of.

B. It is needless to say that the present invention is not limited to the laminated body for the seismic isolation device, and can be applied to heating (preheating) of various laminated bodies in which steel plates and unvulcanized rubber layers are alternately laminated.

C. Although only the laminate A with the flange F has been illustrated, it is needless to say that the present invention can be applied to the laminate A without the flange F.

[0043]

As is apparent from the above description,
The method and apparatus for electromagnetic induction heating of a laminate according to the present invention have the following excellent effects.

(1) According to the first aspect of the present invention, unlike the conventional method in which the laminate is housed in a mold and heated by steam, the inside (center portion) of the unvulcanized rubber layer is also heated by electromagnetic induction heating. Since it is heated simultaneously with the outer periphery, the temperature difference between the inside and outside is small, and the quality is greatly improved. Further, since the time required for vulcanization including preheating is reduced, the running cost is reduced, and it is economical.

(2) According to the second aspect of the present invention, similarly to the heating method of the first aspect, since the laminate can be simultaneously heated from the outer peripheral side and the inner central portion, the laminate is provided between the unvulcanized rubber layers. Heat is conducted from the inner and outer peripheral portions through the laminated steel plates, and the unvulcanized rubber layer can be heated substantially uniformly. As a result, the quality is greatly improved, and the time required for vulcanization including preheating is reduced, so that the running cost is reduced.

(3) In the invention of claim 3, when the unvulcanized rubber of the laminate is vulcanized, the laminate is heated to a predetermined temperature (100 ° C.).
Preheating until the above), then the same laminate is inserted into the mold and the conventional vulcanization with steam is performed. Including the time required for the above, is greatly reduced to about 1/5.

(4) According to the fourth aspect of the invention, immediately after the start of heating, the upper and lower ends of the outer peripheral portion have the highest temperature, and the middle position in the radial direction has the lowest temperature. By controlling the current flowing through the electromagnetic induction coil so as to reach the reference temperature, the highest temperature point due to the electromagnetic induction heating can be suppressed below the set reference temperature, and during this time, the lowest temperature point due to the heat conduction effect via the steel plate etc. The temperature rises and approaches the reference temperature. As a result, it is possible to uniformly heat the unvulcanized rubber layer to a predetermined temperature for the laminates having different sizes and types.

(5) According to the fifth aspect of the present invention, the above-described heating method according to the present invention can be reliably performed, and the structure is simple.
Significantly reduced compared to the running cost of conventional steam heating. In addition, since the lines of magnetic force penetrate the inner and outer peripheral portions of the laminate, the electromagnetic induction efficiency is improved, the heating state of the steel sheet of the laminate is made more uniform, and the unvulcanized rubber layer is more uniformly heated.

(6) In the invention according to claim 6, there is a difference in that steam or hot water is used for heating the central portion of the laminate and an AC power source is used only for the outer peripheral side. At the same time, the unvulcanized rubber layer can be heated substantially evenly, which is almost the same effect as the invention of claim 5.

(7) According to the seventh aspect of the present invention, the prismatic magnetic flux collector made of a thin silicon steel plate collects magnetic lines of force generated by the electromagnetic induction coil and directed to the outside of the case. Since the case of a non-magnetic material usually provided outside the coil to prevent the escape can be omitted, the heat radiation property is improved, and the heat generation of the coil during energization is reduced. Further, since a magnetic flux collector formed by laminating thin silicon steel plates hardly generates heat, there is an effect that it works effectively only for collecting magnetic flux (lines of magnetic force).

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an electromagnetic induction heating device according to the present invention.

FIGS. 2A and 2B are side views showing a forming process of a laminate.

FIG. 3A is a central longitudinal sectional view showing the principle of electromagnetic induction heating according to the present invention, and FIG. 3B is a perspective view showing a steel sheet C in a laminate A.

FIG. 4 is a front sectional view showing the electromagnetic induction heating device according to the first embodiment of the present invention.

FIG. 5A is a front sectional view showing an electromagnetic induction heating device according to a second embodiment of the present invention, and FIG. 5B is a perspective view showing an electromagnetic induction heating device on the outer peripheral side.

FIG. 6 is a front sectional view showing an electromagnetic induction heating device according to a third embodiment of the present invention.

FIG. 7A is a front sectional view showing an electromagnetic induction heating apparatus according to a fourth embodiment of the present invention, and FIG. It is a temperature diagram shown.

FIG. 8 is a temperature diagram showing the maximum and minimum temperatures during preheating and vulcanization according to the present invention in the case of a laminate having an outer diameter of 1000 mm and a height of 375 mm, and a conventional maximum temperature during vulcanization with steam. FIG. 3 is a temperature diagram showing a minimum temperature.

[Explanation of symbols]

1.1 ₁・ 1 ₂・ 1 ₃・ 1 ₄ Electromagnetic induction heating device 2.4 Cylindrical case 3 Electromagnetic induction coil 5 Electromagnetic induction heating device 6.8 Cylindrical case 7 Electromagnetic induction coil 10 Rectangular magnetic flux (electromagnetic wave) ) Collecting body 11 Frame-shaped gantry 12 Plug pin 15.16.17 Thermocouple (Temperature sensor) 21 Cart 22 Lifting mechanism 23 Mounting table 31 Core A Laminated body B Unvulcanized rubber layer C Steel plate F Flange

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FIB29L 9:00 (72) Inventor Masatoshi Umemiya 3-2-1-15 Meiwadori, Hyogo-ku, Kobe-shi, Hyogo BANDO CHEMICAL CO., LTD.

Claims (7)

[Claims] 1. An electromagnetic device comprising: a cylindrical or prismatic laminated body obtained by alternately laminating a circular or square thin steel plate and a circular or square unvulcanized rubber layer around a periphery of the laminated body. Electromagnetic induction heating for heating the unvulcanized rubber layer by passing eddy currents through the steel sheet of the laminate by causing magnetic flux lines generated by passing an alternating current through the induction coil to pass through the steel sheet in a direction perpendicular to the steel sheet, thereby heating the unvulcanized rubber layer. A method wherein a center opening penetrating vertically is provided in advance in a center axis portion of the laminated body in the electromagnetic induction coil, and an external magnetic path type electromagnetic induction coil is inserted into the opening so that the inside and outside are opened. And heating the unvulcanized rubber layer from above. 2. An electromagnetic device comprising: a cylindrical or prismatic laminate formed by alternately laminating a circular or square thin steel plate and a circular or square unvulcanized rubber layer, and disposing the laminate around the laminate. Electromagnetic induction heating for heating the unvulcanized rubber layer by passing eddy currents through the steel sheet of the laminate by causing magnetic flux lines generated by passing an alternating current through the induction coil to pass through the steel sheet in a direction perpendicular to the steel sheet, thereby heating the unvulcanized rubber layer. In the method, a central opening that penetrates vertically is provided in advance in the central axis portion of the laminated body in the electromagnetic induction coil, and a plug-pin-shaped steam-type or hot-water type heating means is provided in the opening. An electromagnetic induction heating method for a laminate, comprising: inserting and heating the unvulcanized rubber layer from inside and outside. 3. The laminate according to claim 1, wherein after the laminate is heated by electromagnetic induction and preheated, the laminate is inserted into a mold, and is heated and vulcanized under a constant pressure. Electromagnetic induction heating method. 4. In the unvulcanized rubber layer of the laminate, a temperature sensor is inserted at each of the upper and lower ends near the outer peripheral surface and at the intermediate position in the radial direction at the upper and lower ends, and at least the three points during electromagnetic induction heating. After controlling the amount of electric power necessary for electromagnetic induction heating so that the highest temperature among them does not exceed the set temperature while measuring the temperature of, the temperature sensor is extracted from the unvulcanized rubber layer before vulcanization. Item 1
4. The method of electromagnetically heating a laminate according to any one of claims 1 to 3. 5. An electromagnetic induction heating apparatus for heating a cylindrical or prismatic laminate obtained by alternately laminating a circular or square thin steel plate and a circular or square unvulcanized rubber layer. A coil for electromagnetic induction is wound around almost the entire outer peripheral surface of a cylindrical case made of a non-magnetic material capable of completely housing the laminate, and connected to an AC power supply. The laminated body characterized in that it is provided in advance with a central opening penetrating up and down, and an external magnetic path type electromagnetic induction coil is inserted into the opening to heat the unvulcanized rubber layer from inside and outside. Electromagnetic induction heating device. 6. An electromagnetic induction heating apparatus for heating a cylindrical or prismatic laminate obtained by alternately laminating circular or square thin steel plates and circular or square unvulcanized rubber layers. A coil for electromagnetic induction is wound around almost the entire outer peripheral surface of a cylindrical case made of a non-magnetic material capable of completely housing the laminate, and connected to an AC power supply. A central opening penetrating vertically is provided in advance, and the unvulcanized rubber layer can be heated from inside and outside by inserting a plug pin-shaped steam or hot water type heating means into the opening. Electromagnetic induction heating device for laminates. 7. A coil for electromagnetic induction is wound around substantially the entire outer peripheral surface of the cylindrical case made of a non-magnetic material, and a strip having a constant width and the same height as the cylindrical case is very thin. The laminate according to claim 5 or 6, wherein a plurality of electromagnetic wave collectors formed in a prismatic shape by laminating a plurality of silicon steel sheets are arranged on the outer periphery of the coil for electromagnetic induction at intervals in the circumferential direction. Electromagnetic induction heating device.