JP6697801B2 - Induction heating coil - Google Patents

Description

  The present invention relates to an induction heating coil which is inserted into a shaft hole provided in a large metal bolt for tightening a flange in a steam turbine chamber and used when heating the shaft hole by induction heating.

  Conventionally, this type of induction heating coil is disclosed in, for example, Patent Document 1. This induction heating coil has a plurality of U-shaped coils made of a metal pipe having a circular cross section formed in an elongated U-shape, and a coil main body that can be elastically bent in the U-shaped plane, and the coil main body. And a magnetic body in which a plurality of thin plates that can be bent in the same direction as the coil body and are stacked inside the U shape are laminated. When the coil body is bent in the U-shape, the thin plates of the magnetic material slide against each other and are bent, and even when the flange or the like is located above the head of the metal bolt, the bent heating coil is placed in the shaft hole. It can be inserted into.

Japanese Patent No. 3624983

  However, in such an induction heating coil, the coil body is formed of a plurality of U-shaped coils, and the magnetic body is also formed of a plurality of thin plates, which can be bent by sliding on each other. Since the structure is complicated, the structure for bending the heating coil becomes extremely complicated and the bending work is complicated, and the number of members of the heating coil increases and the heating coil itself becomes heavy and it is inserted into the shaft hole. The work efficiency of the work of heating the shaft hole is inferior because the work becomes troublesome. At the same time, due to the complicated structure of the coil body and the magnetic body, the manufacturing of the heating coil is complicated and the cost is high.

  The present invention has been made in view of such circumstances, and an object thereof is to easily perform bending work, handling, etc., and improve efficiency of heating work of a shaft hole, and simplify the configuration. An object of the present invention is to provide an induction heating coil that can be easily manufactured and can reduce the cost of the coil itself and the cost of heating work.

In order to achieve such an object, the invention according to claim 1 of the present invention is a coil body made of an annealed copper tube having a circular cross section, which is formed in an elongated U shape and terminal plates are connected and fixed to both ends thereof. An elastic insulator disposed inside the U-shape of the coil body, and an elastic covering member that covers the insulator and the outer peripheral side of the coil body. Further, by bending the copper pipe, it has a U-shaped portion forming a heating portion and a pair of linear portions of a predetermined length, and the insulator bends following the bending in the direction orthogonal to the U-shaped surface of the coil body. Is formed of a resin plate having a predetermined plate thickness that is substantially the same as the length of the heating portion, and the surface of the resin plate that is orthogonal to the U-shaped surface is sandwiched by a pair of linear portions of the coil body. with the said covering member, the formed glass tape which is arranged wound with a predetermined space between the insulator to the outer surface of the coil body while abutting, moderation the said coil body When the elasticity of the copper pipe is used to bend in a direction orthogonal to the U-shaped surface , the insulator and the covering member can be bent in the same direction substantially at the same time.

Further, the invention according to claim 2 is a coil main body made of an annealed copper tube having a circular cross section, which is formed in an elongated U shape and terminal plates are connected and fixed to both ends thereof, respectively, and a U shape of the coil main body. An elastic insulator disposed inside, and an elastic covering member that covers the insulator and the outer peripheral side of the coil main body, wherein the coil main body is formed by bending the annealed copper tube. Having a U-shaped portion and a pair of linear portions having a predetermined length, and the insulator is bendable in accordance with the bending of the coil body in a direction orthogonal to the U-shaped surface and has a predetermined gap. The covering member is formed of a plurality of cores of a predetermined length that are continuously arranged, and a surface of the core orthogonal to the U-shaped surface is sandwiched by a pair of linear portions of the coil body, and the covering member is provided. Formed by a glass tape that is wound around the outer surface of the coil body with a predetermined space between the coil body and the insulator, and uses the elasticity of the annealed copper tube to form the coil body. When bent in a direction orthogonal to the U-shaped surface, the insulator and the covering member are bent in the same direction at substantially the same time .

Further, in the invention according to claim 3, the coil main body has a connecting portion that is bent outward at an end of each of the linear portions, and each terminal plate is also a connection that is bent inward at a base end side. Since each of the terminal portions has a gap larger than the U-shaped width of the coil main body and is orthogonal to the U-shaped surface of the insulator by connecting and fixing the two connecting portions to each other. It is characterized in that it is arranged opposite to each other in parallel with both sides .

In the invention according to claim 4 , the terminal plate is arranged such that the terminal plate is wound around the I-shaped core a predetermined number of times to surround the primary coil and the secondary coil, and the primary coil and the secondary coil. , And an output terminal of an output transformer having a cylindrical case arranged on the outer peripheral side of the ring core, directly or via a connection cable. According to a fifth aspect of the invention, in the output transformer, the cylindrical case is formed of an insulating cylindrical pipe, and an insulating installation plate is arranged on an outer peripheral surface of the cylindrical pipe. It is characterized by being. Still further, in the invention according to claim 6, both ends of the coil body are fixed to the outer side surfaces of the pair of terminal plates, respectively, and the cooling medium is provided at both ends of the coil body in the smoothed copper pipe. It is characterized in that the hose connectors capable of circulating and supplying are respectively fixed .

According to the first or second aspect of the present invention, when the coil body is bent in a predetermined direction by utilizing the elasticity of the smoothed copper tube, the elastic insulator and the covering member are in the same direction. Since the heating coils can be bent at almost the same time, the bending work of the heating coil can be facilitated and the handling can be performed easily, the efficiency of the heating work of the shaft hole can be improved, and the heating coil itself can be easily manufactured with a simple structure. As a result, the cost of the coil itself and the cost of the heating work can be reduced.

In addition, since the insulator is a resin plate that can be bent in a direction orthogonal to the U-shaped surface or a core in a continuous state, by using a resin plate having substantially the same length as the coil body and a predetermined plate thickness, the heating coil The structure of can be further simplified and its weight can be reduced, and the use of cores in a continuous arrangement with a gap increases the heating efficiency of the heating coil and further reduces the cost of heating work. Can be promoted. Moreover, since the insulator is bent in a direction orthogonal to the U-shaped surface, the shape of the heating coil in the longitudinal direction is stabilized while maintaining the positional relationship between the insulator and the coil body, and the heating coil is made uniform over the entire axial hole. The heating state can be easily obtained.

Further, according to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the connection parts at both ends of the coil body and the connection parts at the base end side of each terminal plate are connected to each other. Since they are fixed and the distal ends of the respective terminal plates are opposed to each other with a gap larger than the U-shaped width of the coil body, the connection work between the terminal plates and the output terminals of the output transformer can be easily performed. At the same time, even if the coil body has a narrow U-shaped width, it is possible to reliably prevent contact between the terminal plates and the like, and easily obtain a stable heating state at all times .

According to the invention described in claim 4, in addition to the effects of the invention described in claims 1 to 3 , the ring core surrounds the terminal coil so as to surround the primary coil and the secondary coil wound around the I-shaped core. And the output terminal of the output transformer equipped with a tubular cover that is placed outside the ring core is connected directly or via a connecting cable, so a small and lightweight output transformer can be installed in the heating worksite. It is possible to further improve the heating efficiency and the heating work efficiency, for example, by disposing it in the vicinity and easily performing the heating work .

According to the invention described in claim 5, in addition to the effect of the invention described in claim 4 , the tubular case of the output transformer is formed of an insulating cylindrical pipe, and the outer periphery of the cylindrical pipe is Since the insulating installation plate is arranged on the surface, when the output transformer is installed (placed) on the installation surface such as the flange surface of the heating work site, the rotation of the cylindrical pipe is restricted, A stable and efficient heating state of the shaft hole can be easily obtained by, for example, ensuring a predetermined positional relationship with respect to the shaft hole of the heating coil connected and fixed to the output transformer .

Furthermore, according to the invention described in claim 6, in addition to the effects of the invention described in claims 1 to 5, both ends of the coil body are fixed to the outer surfaces of the pair of terminal plates, respectively, and the coil body is Since the hose connectors that can circulate and supply the cooling medium are fixed to both ends of the coil inside the smoothed copper pipe, the coil body can be reliably cooled, and the heating efficiency is reduced due to the heat generated by the heating coil. By suppressing it, the efficiency of the heating work can be further improved .

1 is a schematic side view showing an embodiment of an induction heating coil according to the present invention. Same as above Sectional drawing which followed the AA line of the same FIG. Explanatory drawing which shows an example of the connection state of the same heating coil FIG. 2 is a schematic side view showing another embodiment of the induction heating coil according to the present invention. Same as above Sectional drawing which followed the BB line of the same FIG. Sectional drawing which followed CC line of the same FIG.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
1 to 4 show an embodiment of an induction heating coil according to the present invention. As shown in FIGS. 1 to 3, an induction heating coil 1 (referred to as a heating coil 1) includes a coil main body 2 formed by bending into an elongated U-shape (hairpin) shape, and an electric coil at an end of the coil main body 2. A pair of terminal plates 3 that are mechanically connected and fixed, an insulator 4 arranged inside the U-shape of the coil body 2, and a covering member 5 that covers the insulator 4 and the outer peripheral side of the coil body 2. (See FIG. 3).

The coil body 2 has a predetermined outer diameter and a predetermined wall thickness (for example, outer diameter=6 mm and wall thickness=1.0 mm ), and has a circular cross section and is made of bare annealed copper whose outer peripheral surface is not covered with an insulating material. A U-shaped portion 2a1 forming a heating portion 2a and a pair of linear portions 2a2 having a predetermined length, which are formed by bending a pipe into a U-shape, and a connection formed at an end of each linear portion 2a2 of the heating portion 2a. It has a part 2b. The connecting portion 2b is formed in a substantially L shape in a side view, and has a pair of horizontal portions 2b1 bent outward from a U-shaped portion at a predetermined angle (for example, about 20 degrees ) with respect to each linear portion 2a2 of the heating portion 2a, Each horizontal portion 2b1 is formed with a vertical portion 2b2 that is continuously provided in the vertical direction.

  The terminal plate 3 is formed of a copper plate having a plate thickness of, for example, 3 mm and having a substantially rectangular shape in a side view. And fixing grooves 3a are formed respectively, and a connecting portion 3b bent inward corresponding to the connecting portion 2b of the coil body 2 is formed on the tip side. By fixing the connecting portion 2b of the coil body 2 to the outer surface of the connecting portion 3b by brazing, the coil body 2 and the terminal plate 3 are integrated, and the U of the coil body 2 is interposed between the pair of terminal plates 3. A gap (for example, 12 mm) wider than the width of the character is secured. Further, the tip of the vertical portion 2b2 of each connecting portion 2b projects a predetermined amount outward (upward) in the height direction of each terminal plate 3, and the hose connector 6 is fixed to this projecting portion.

  The insulator 4 is made of a plate-shaped fluororesin having a predetermined plate thickness (for example, 5 mm) and a length substantially the same as the length of the heating part 2a, and is sandwiched by a pair of linear parts 2a2 in the U-shape of the coil body 2. It is arranged in a closed state. The covering member 5 is formed by triple winding a glass tape having a predetermined thickness (for example, 0.16 mm). At this time, as shown in FIG. 3, the covering member 5 contacts the outer surface of the coil body 2. A predetermined space 7 is formed between the insulator 4 and the insulator 4 while being in contact with each other.

  The insulator 4 and the covering member 5 are arranged so that the coil body 2 utilizes the elasticity of the annealed copper tube, as shown by the two-dot chain lines a and b in FIG. When bent to a predetermined radius (for example, R=250), the elasticity of the fluororesin and the elasticity of the glass tape follow the bending of the coil body 2 so that they can be bent substantially simultaneously in the same direction. ..

  FIG. 4 shows a connection state of the heating coil 1. As shown in FIG. 4, in the heating coil 1, each terminal plate 3 is directly connected and fixed to the output terminal 11 of the output transformer 10, and the input terminal 12 of the output transformer 10 is connected via the connection cable 13 to the transistor. A hose connector 15 connected to the inverter 14 and on the side of the input terminal 12 and a cooling water supply device 16 are connected by a cooling water hose 17.

  Here, the configuration of the output transformer 10 to which the heating coil 1 of the present invention is connected will be described. As shown in FIG. 4, the output transformer 10 has a cylindrical case 10a whose outer shape is formed into a cylindrical shape having a predetermined length, and a pair of the output terminals 11 are provided on the output (secondary coil) side. A pair of the input terminals 12 are provided on the input (primary coil) side.

  The output terminal 11 is a terminal portion 11a made of a pair of copper plates press-contacted and fixed via a front edge plate, and fixed to the both terminal portions 11a, the tips of which are projected to both outer surface sides, and wing nuts 11b are respectively screwed in. And a copper pipe, a hose connector 11d, and the like, which are fixed to the outer surface of the terminal portion 11a by brazing and are connected to the ends of the secondary coil. The input terminal 12 has a terminal portion 12a made of a pair of copper plates pressed and fixed via an insulating plate, and a bolt and a nut for fixing the terminal portion 12a. Is provided with the hose connector 15 for supplying cooling water.

  Further, the output transformer 1 is formed into a rectangular parallelepiped shape as a whole by connecting a plurality of ferrite cores inside the insulating cylindrical case 10a having a predetermined length, such as a vinyl chloride pipe. An I-shaped core arranged in a vertical state and a single winding that is arranged in a horizontal state around an intermediate position in the height direction of the I-shaped core and is formed in a substantially U-shape in a plan view by a copper square pipe. -Shaped secondary coil, a primary coil consisting of a round copper pipe wound around the I-shaped core a predetermined number of times on the upper and lower surfaces of the secondary coil and covered with an insulating material on the outer peripheral surface, and these primary coils and secondary coils. It has a plurality of ring cores (none of which are shown) arranged continuously in the longitudinal direction so as to cover the outer peripheral surface of the next coil.

  Both ends of the primary coil are connected to the pair of terminal portions 12a of the input terminal 12, and both ends of the secondary coil are connected to the pair of terminal portions 11a of the output terminal 11. At the same time, a hose connector 15 provided on the side of the input terminal 11 is connected to the end of the round pipe of the primary coil and the end of the square pipe of the secondary coil by a cooling water hose or the like not shown. .

  An installation plate 18 is arranged at, for example, an intermediate position in the longitudinal direction of the cylindrical case 10a of the output transformer 1. The installation plate 18 is formed of an insulating plate material having a predetermined length and a predetermined width, such as a TC board, and is supported by a support member 18a formed of a plurality of plates on the outer peripheral surface of the cylindrical case 10a of the output transformer 10. Has been done. The support member 18a is supported and fixed to the outer peripheral surface of the cylindrical case 10a in a state where its rotation is restricted, so that the horizontal installation plate 18 is orthogonal to each vertical terminal portion 11a of the output terminal 11. It is supposed to do.

  The heating coil 1 is connected to the output transformer 10 configured as described above as follows. That is, as will be described later, each terminal plate 3 of the heating coil 1 in which the coil body 2 is bent into a predetermined shape, and the fixing groove 3a thereof are provided in each terminal portion 11a of the output terminal 11 of the output transformer 10. It is fitted between the bolt 11c and each wing nut 11b, and the screw nut 11b is tightened to fix the terminal portion 11a in the surface contact pressure contact state. At this time, the fixed angle (direction) of the heating coil 1 with respect to the output terminal 11 of the output transformer 10 is set so that the heating coil 1 (coil body 2) faces downward by 90 degrees with respect to the terminal portion 11a.

  Then, after fixing each terminal plate 3 of the heating coil 1 to the output terminal 11 of the output transformer 10, the hose connector 6 provided on each terminal plate 3 of the heating coil 1 and each terminal portion of the output transformer 10. The hose connector 11d provided on 11a is connected by the cooling water hose 8. As a result, the heating coil 1 is connected and fixed to the output terminal 11 of the output transformer 10, both ends of the secondary coil of the output transformer 10 are electrically connected to the pair of terminal plates 3, and a pair of hoses is formed. The connectors 11d and 6 and the cooling water hose 8 form a circulation channel for cooling water.

  The output transformer 10 has an input terminal 12 electrically connected to an output terminal of a transistor inverter 14 via a coaxial connection cable 13, and a hose connector 15 via a cooling water hose 17. , And is connected to a cooling water supply device 16 arranged in the same housing as the transistor inverter 14. As a result, a current having a predetermined frequency of the transistor inverter 14 is supplied to the primary coil via the connection cable 13 and the input terminal 12, and a current induced in the secondary coil is supplied to the heating coil via the output terminal 11 and the terminal plate 3. 1 is supplied to the coil body 2. Further, the cooling water is circulated and supplied from the cooling water supply device 16 to the coil body 2 via the cooling water hose 17, the primary coil, the secondary coil, and the cooling water hose 8.

  That is, the heating coil 1 has an output in which the terminal plate 3 has an I-shaped core or a ring core continuously arranged in the cylindrical case 10a and efficiently arranges a primary coil and a secondary coil with respect to these cores. It will be directly connected to the output terminal 11 of the transformer 10. As a result, by setting the current input from the transistor inverter 14 to the output transformer 10 to a predetermined value, a desired current can be directly supplied from the output transformer 10 to the heating coil 1, and the output transformer 10 and the heating coil 1 can be supplied. It is not necessary to consider the current loss during that time, and the heating conditions for the heating coil 1 at the heating work site can be set easily and reliably.

  Further, the output transformer 10 itself suppresses the leakage of magnetic flux by increasing the coupling coefficient (turn ratio) of the primary coil and the secondary coil by effectively disposing the I-type core, the ring core, and the primary coil and the secondary coil. Therefore, a compact and high-power output transformer 10 can be obtained, and is used as the optimum output transformer 10 when performing work while moving the heating coil 1 in the heating work site like the heating coil 1 of the present invention. You can do it.

  The configuration of the output transformer 10 is not limited to the illustrated example. For example, a rectangular parallelepiped I-shaped core is arranged in the U-shaped recess of the plate-shaped secondary coil having a U-shaped plan view. The primary coil may be wound a plurality of times above and below the secondary coil on the outer side of the I-shaped core via a thin insulating plate or the like, and the ring core may be arranged on the outer side of the secondary coil. Further, the installation position of the installation plate 18 of the output transformer 10 is not limited to the intermediate position in the longitudinal direction of the cylindrical case 10a, but may be installed at both ends in the longitudinal direction, and the cylindrical case has a cylindrical shape. However, the shape may be a rectangular tube. Further, the configuration for supporting and fixing the installation plate 18 to the cylindrical case 10a is not limited to the illustrated supporting member 18a, and an appropriate configuration capable of supporting and fixing the installation plate 18 to a predetermined position of the cylindrical case 10a may be adopted. You can

  Next, an example of how to use the heating coil 1 will be described. First, the output transformer 10 is connected to the transistor inverter 14 and the cooling water supply device 16 installed at the heating work site via the connection cable 13 and the like. Then, the output transformer 10 is placed in the vicinity of the heating work site, and the installation plate 18 is placed on the installation surface such as the flange surface or the workbench to install the output transformer 10. At this time, when the output transformer 10 is placed on the installation surface, the installation plate 18 holds the output transformer 10 on the installation surface with the rotation of the cylindrical case 10a (output transformer 10) restricted. become.

  When the output transformer 10 is installed on the installation surface, the coil body 2 of the heating coil 1 in the linear state shown by the solid line in FIG. 1 is bent into a predetermined shape according to the situation of the shaft hole of the metal bolt at the heating point, Insert into the shaft hole of the metal bolt. At this time, since the heating coil 1 can be bent in the direction orthogonal to the U-shaped surface of the coil body 2, the heating coil 1 is inserted into the shaft hole while considering the bending direction. After the heating coil 1 is set in the shaft hole, the terminal plates 3 of the heating coil 1 are inserted into the respective terminal portions 11a of the output terminals 11 of the output transformer 10 installed on the installation surface as described above, and the wing nut 11b is inserted. Fix with. As a result, the heating coil 1 and the output transformer 10 are integrated, and the shaft hole is set to a state in which induction heating is possible.

  Then, while maintaining this state, that is, while maintaining the insertion state of the heating coil 1 connected and fixed to the output transformer 10 into the shaft hole, for example, a heating switch or a remote controller (not shown) provided in the output transformer 10 is operated. While supplying a current of a predetermined frequency from the transistor inverter 14 to the coil body 2 via the output transformer 10, the cooling water supply device 16 cools each coil of the output transformer 10 and the annealed copper pipe of the coil body 2. Circulates water.

  When, for example, a high frequency current is supplied to the coil body 2, the inner surface of the shaft hole of the metal bolt is induction-heated by the eddy current, and the metal bolt expands and is withdrawn from the hole of the flange. Moreover, the output transformer 10 and the coil main body 2 are cooled by the cooling water circulated and supplied during heating, and a decrease in heating efficiency due to heat generation of these is suppressed. By repeating this operation for the adjacent metal bolts in order, the metal bolts of the flange in the steam turbine chamber fixed with a large number of metal bolts are removed.

  When the metal bolt is pulled out by heating the shaft hole, the heating coil 1 is directly connected and fixed to the output terminal 11 of the output transformer 10 which is small and easy to carry. Also, it is possible to easily move the work at the start or end of the work. If the heating coil 1 can be linearly inserted from the axial direction into the shaft hole of the metal bolt, the heating work is not performed by bending the heating coil 1 in the straight line state shown in FIG. Needless to say.

  As described above, according to the heating coil 1, when the coil body 2 is bent in the direction orthogonal to the U-shaped surface by utilizing the elasticity of the smoothed copper tube, the insulating body 4 and the covering member 5 each having elasticity are formed. Since they can be bent at the same time in the same direction, a large bending force is not required, and the bending work can be facilitated and the heating coil 1 itself can be easily handled, and the heating work of the shaft hole of the metal bolt can be performed. The efficiency of the heating coil 1 can be improved, and the heating coil 1 itself and the heating coil 1 can be easily manufactured by simplifying the configuration, and thus the cost of the heating coil 1 itself and the cost of the heating operation can be reduced.

  Further, since the insulator 4 is formed of a resin plate that can be bent in a direction orthogonal to the U-shaped surface, the coil body 2 can be formed by using a fluororesin plate having substantially the same length as the coil body 2 and a predetermined thickness. It is possible to further simplify the configuration of the heating coil 1 and to reduce its weight while maintaining the U-shape and the insulating state between the pair of linear portions 2a2 in a stable manner. At the same time, since the insulator 4 is bent in a direction orthogonal to the U-shaped surface, the positional relationship between the insulator 4 and the coil body 2 is stably maintained, and the pair of linear portions 2a2 of the coil body 2 come into contact (short circuit). It is possible to stabilize the shape of the heating coil 1 in the longitudinal direction while preventing the above, and to easily obtain a uniform heating state over substantially the entire axial hole.

  In addition, each terminal board 3 is provided with a ring core so as to surround the primary coil and the secondary coil wound around the I-shaped core, and the output transformer 10 including the cylindrical case 10a disposed outside the ring core. Since it is directly connected and fixed to the output terminal 11 of, the small and lightweight output transformer 10 can be arranged near the heating work site to easily perform the heating work, and the heating efficiency and the heating work efficiency can be further improved. It is possible to improve.

  In particular, since the output transformer 10 has the insulating cylindrical case 10a, the insulating installation plate 18 and the support member 18a, the output transformer 10 can be installed on a predetermined installation surface while reducing the outer diameter shape. In addition to being able to be stably installed, heat generation of the cylindrical case 10a and the installation plate 18 itself can be prevented, and the heating work can be performed more safely. Further, since the installation plate 18 and the support member 18a are disposed at the intermediate position in the longitudinal direction of the cylindrical case, these can function as the weight balancer of the output transformer 10, and the upper support member 18a can be used. It is possible to further improve the usability of the output transformer 10 having a cylindrical outer diameter such that it can function as a lifting plate.

  Further, the connecting portions 2b at both ends of the coil body 2 are brazed and fixed to the outer surfaces of the pair of terminal plates 3, respectively, and cooling water can be circulated and supplied into the smoothed copper pipe at the tip of the vertical portion 2b of the connecting portion 2b. Since the hose connectors 6 are fixed to each other, the coil body 2 can be surely cooled, the heating efficiency of the heating coil 1 is prevented from being lowered by heat generation, and the heating work is further improved in efficiency. Can be planned.

  Further, the horizontal portion 2b1 and the vertical portion 2b2 of the connecting portion 2b of the coil body 2 and the base end side connecting portion 3b of the terminal plate 3 are connected and fixed to each other, and the base end side of the pair of terminal plates 3 is attached to the coil body 2. Since they are arranged opposite to each other with a gap larger than the U-shaped width, the connection work between the terminal plate 3 and the output terminal 11 of the output transformer 10 can be easily performed, and the U-shaped width of the coil body 2 can be increased. Even in the case of a narrow space, it is possible to reliably prevent contact between the pair of terminal plates 3 and the like, and easily obtain a stable heating state at all times.

  From these, the structure of the heating coil 1 for heating the shaft hole of the metal bolt is extremely simple, and the heating coil 1 that is easy to bend and is inexpensive can be obtained. When heating work in a steam turbine chamber that requires heating, the heating coil 1 that has become difficult to bend due to use (heating by bending or energization) is made into a disposable, and the heating work is performed using the new easy-to-bend heating coil 1. Therefore, it is possible to further improve the efficiency of the heating work.

  5 to 8 show another embodiment of the heating coil 1 according to the present invention. Hereinafter, the same parts as those of the above-described embodiment will be described with the same reference numerals. The heating coil 1 of this embodiment is characterized in that the insulator 4 is formed by a plurality of cores 4a that are continuously arranged at a predetermined gap, instead of a resin plate having elasticity such as fluororesin. That is, a plurality of (six in the figure) cores 4a of a rectangular parallelepiped shape having a predetermined plate thickness and a predetermined length are provided in the longitudinal direction of the coil body 2 with a predetermined gap 19 therebetween, and Place in U shape. Then, by covering the coil body 2 made of annealed copper tube and each core 4a with the covering member 5 made of glass tape, each core 4a has a predetermined gap 19 in the U shape of the coil body 2. Deploy.

  According to the heating coil 1 of this embodiment, since the cores 4a are continuously arranged with a predetermined gap 19, when the coil body 2 is bent in a direction orthogonal to the U-shaped surface, The short adjacent cores 4a are also bent while being covered with the glass tape until their end face corner portions come into contact with each other. Also in this heating coil 1, in addition to the same effects as those of the heating coil 1 of the above-described embodiment, since a plurality of cores 4a are arranged in the U-shape of the coil body 2, the magnetic flux of each core 4a The heating efficiency of the heating coil 1 can be improved by suppressing leakage, and the output transformer 10 and the transistor inverter 14 connected to the heating coil 1 can be further downsized and the heating work cost can be further reduced. It can be planned. In the case of this example, an insulating material having appropriate elasticity may be interposed in the gap 19 between the cores 4a.

  In the above embodiment, each dimension shows the case where the outer diameter of the coil is 18 mm, but the heating coil 1 of the present invention can be applied to, for example, a metal bolt having an inner diameter of the shaft hole of 10 to 30 mm. The outer diameter thereof is also set to about 8 to 28 mm, and each of the above dimensions is set in accordance with this dimension.

  Further, in the above-described embodiment, the resin plate or the core 4a is used as the insulator 4, but the present invention is not limited to this. For example, instead of the plate-shaped insulator 4, a prismatic fluororesin or the like may be used. By using the excellent insulator 4, the coil body 2 can be bent in the U-shape and in the direction orthogonal to the U-shape, or the entire outer peripheral surface of the annealed copper pipe is excellent in insulation and heat resistance. By covering with a thick insulating member, the insulating member can have both functions of the insulator 4 and the covering member 5, so that the coil body 2 can be bent in all directions, for example.

Furthermore, the form of the connecting portion 2b of the coil body 2, the form of the terminal plate 3, the connecting structure of the heating coil 1 and the output transformer 10 and the like in each of the above embodiments are examples, and for example, the terminal plate 3 of the heating coil 1 is used. Is connected to the output terminal 11 of the output transformer 10 via a connection cable having a short length to further facilitate the winding of the heating coil 1. Can be appropriately changed without departing from the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention is not limited to application to metal bolts for tightening flanges of steam turbine chambers, but has all the metal bolts that have a shaft hole at the center position and require heating to tighten or loosen the bolts, or It can be used for all metal products that need to be heated.

  DESCRIPTION OF SYMBOLS 1... Induction heating coil, 2... Coil main body, 2a... Heating part, 2b... Connection part, 3... Terminal plate, 3a... Fixing groove, 3b... Connection part 4... Insulator, 4a... Core, 5... Covering member, 6... Hose connector, 7... Space, 10... Output transformer, 11... Output terminal, 12 ... Input terminal, 13... Connection cable, 14... Transistor inverter, 15... Hose connector, 16... Cooling water supply device, 17... Cooling water hose, 18... Installation plate , 18a... Support member, 19... Gap.

Claims (6)

A coil body formed of an annealed copper tube having a circular cross-section, which is formed in an elongated U shape and has terminal plates connected and fixed to both ends thereof, and an elastic insulator disposed inside the U shape of the coil body. Including the insulator and an elastic covering member for covering the outer peripheral side of the coil body,
The coil body has a U-shaped portion forming a heating portion and a pair of linear portions having a predetermined length by bending the smoothed copper tube,
The insulator is formed of a resin plate having a predetermined plate thickness that is substantially the same as the length of the heating portion and can be bent following the bending of the coil body in a direction orthogonal to the U-shaped surface. A surface orthogonal to the U-shaped surface is arranged in a state of being sandwiched by a pair of linear portions of the coil body, and the covering member is in contact with an outer surface of the coil body and has a predetermined space between the insulator and the insulator. Formed with a glass tape that is wound and arranged,
Induction heating coil, characterized in that when the bending in a direction perpendicular to the said coil body by utilizing the elasticity of the smoothing copper tube the U-shaped surface, the insulator and the cover member is bent substantially at the same time in the same direction . A coil body formed of an annealed copper tube having a circular cross-section, which is formed in an elongated U shape and has terminal plates connected and fixed to both ends thereof, and an elastic insulator disposed inside the U shape of the coil body. Including the insulator and an elastic covering member for covering the outer peripheral side of the coil body,
The coil body has a U-shaped portion forming a heating portion and a pair of linear portions having a predetermined length by bending the smoothed copper tube,
The insulator is formed of a plurality of cores each having a predetermined length, which can be bent following a bending in a direction orthogonal to the U-shaped surface of the coil body and are continuously arranged with a predetermined gap. A surface orthogonal to the U-shaped surface is arranged in a state of being sandwiched by a pair of linear portions of the coil body, and the covering member is in contact with an outer surface of the coil body while being provided with a predetermined space. Formed with glass tape that has a space and is wound,
An induction heating coil , characterized in that, when the coil body is bent in a direction orthogonal to the U-shaped surface by utilizing the elasticity of the annealed copper tube, the insulator and the covering member are bent substantially in the same direction at the same time. . The coil body has a connecting portion that is bent outward at the end of each of the linear portions, and each terminal plate also has a connecting portion that is bent inward at the base end side. Since the terminal plates are connected and fixed to each other, the front end sides of the terminal plates are arranged in parallel with both surfaces of the insulator, which are orthogonal to the U-shaped surface, with a gap larger than the U-shaped width of the coil body. induction heating coil of claim 1 or 2, characterized in that there. The terminal plate is provided with a primary coil and a secondary coil wound around an I-shaped core a predetermined number of times, a ring core arranged so as to surround the primary coil and the secondary coil, and an outer peripheral side of the ring core. The induction heating coil according to any one of claims 1 to 3, wherein the induction heating coil is connected to an output terminal of an output transformer having a cylindrical case directly or via a connection cable . 5. The output transformer, wherein the cylindrical case is formed of an insulating cylindrical pipe, and an insulating installation plate is arranged on an outer peripheral surface of the cylindrical pipe. The induction heating coil described in 1. Both ends of the coil body are fixed to the outer surfaces of the pair of terminal plates, and hose connectors that can circulate and supply a cooling medium in the smoothed copper pipe are fixed to both ends of the coil body. induction heating coil according to any one of claims 1 to 5, characterized in that there.

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