JPH0686621B2 - High frequency induction heating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention uses a pair of mosquito coil type primary coils as a primary coil of a current transformer, and high-frequency heating for heating a work between these primary coils. A high-frequency heating method and apparatus for sequentially quenching a plurality of secondary coils integrally formed with a coil and provided on a turntable by rotating the turntable in a step-like manner to sequentially quench a workpiece arranged in an opening in the secondary coil. Regarding

<Conventional Technology> A conventional technology will be described below with reference to the drawings. FIG. 5 is an explanatory view of an example of a high frequency induction heating device for sequentially heating a large number of stud pins.

First, turn the stud pin W, which is a workpiece, into the turntable 5
Placed by hand or machine on one of the mounting table of the workpiece mounting table 6 provided plural in the upper (the position of the stud pin W _1). The work table 6 has a stud pin W
Is stably placed on the work placing table 6,
A recess 6a having a shape corresponding to the outer shape of the stud pin W is formed.

When the turntable 5 rotates around the shaft 7 in the direction of the arrow A by a predetermined angle and then stops, and the stud pin W comes directly under the high frequency heating coil 4 (position of the stud pin W ₂ ), the current transformer 3 heats the high frequency. Together with the coil 4, the high frequency heating coil 4 surrounds the stud pin W by descending in the direction of arrow B by a coil lifting device (not shown). Then, the high frequency current supplied from the high frequency power source 1 to the primary coil (not shown) of the current transformer 3 via the flexible conductor 2 passes through the secondary coil (not shown) of the current transformer 3 to the high frequency heating coil 4 for a predetermined time. The stud pin W is heated by being energized.

When this heating is completed, the cooling liquid is injected from a cooling liquid injection hole (not shown) provided on the surface of the high-frequency heating coil 4 facing the stud pin W, and the quenching of the stud pin W is completed. After that, the current transformer 3 is the high frequency heating coil 4
At the same time, it is lifted by the coil lifting device in the direction opposite to the arrow B. Then, the turntable 5 rotates by a predetermined angle in the direction of arrow A and stops (position of the stud pin W ₃ ), so that the stud pin W is removed from the work mounting table 6 manually or by a machine.

<Problems to be Solved by the Invention> As described above, in the conventional high-frequency induction heating device, since the current transformer 3 having a large weight is moved up and down, a device for raising and lowering the current transformer 3 is required. Not only is the structure of the high-frequency induction heating device complicated, but the cost is also increased.

Next, in order to form a deep hardened layer, it is necessary to use low-frequency electric power, but if the frequency is low, the magnetic flux density generated by the primary coil of the current transformer is small, so an induction current sufficient to heat the work is generated. It is difficult to generate on the work. Therefore, the number of turns of the primary coil is increased in order to increase the inductance of the primary coil, but this increases the weight of the current transformer, which further increases the cost of the device for raising and lowering the current transformer.

The present invention was devised in view of the above circumstances, and it is not necessary to move the current transformer up and down. Therefore, the structure is simple and inexpensive, and a sufficient induced current can be generated in a work even at a low frequency. It is an object of the present invention to provide a high-frequency induction heating method and device that can be used.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the high-frequency induction heating method of the present invention has a substantially plate-like shape having first and second openings and a narrow gap connecting these openings. A work is set in the second openings of the secondary coils radially provided on the table, and one of the secondary coils is above the secondary coil and the other is below the turntable. A pair of 1's arranged close to and fixed to the secondary coil and the turntable and formed to correspond to the shape of the peripheral portion of the first opening.
A secondary coil is arranged between the secondary coils, a pair of primary coils and the peripheral portion form a plane-opposing current transformer, and a heating coil is formed in the peripheral portion of the second opening, After the high-frequency current is passed through the primary coil to finish heating the work, the turntable is rotated to dispose the peripheral portion of the next secondary coil between the primary coils so that the second coil of the second secondary coil is The work installed in the opening is heated.

In order to solve the above problems, the high-frequency induction heating device of the present invention has a plurality of substantially plate-shaped secondary coils radially provided on an insulating turntable, and one of these secondary coils. A pair of primary coils fixedly provided above the secondary coil and below the turntable is provided, and the secondary coil is provided with first and second openings and a narrow gap connecting both the openings. The primary coil is formed so as to correspond to the shape of the peripheral portion of the first opening, and the primary coil on the upper side is disposed close to and facing the peripheral portion, and the primary coil on the lower side is disposed on the peripheral side. A pair of primary coils and a peripheral portion of which a current transformer of a plane opposing type is formed by arranging the pair of primary coils facing each other and close to a turntable, and a heating coil is formed in the peripheral portion of the second opening. Is characterized by.

<Operation> When a high frequency current is applied to the primary coil for a predetermined time, an induced current flows around the first opening, the narrow gap and the second opening of the secondary coil. Due to this induced current, an induced current flows through the work set in the second opening and the work is heated. After that, the turntable is rotated to heat the work set in the second opening of the next secondary coil in the same manner as the first work.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings. 1 to 4 are drawings for explaining a high-frequency heating device capable of realizing the high-frequency heating method of the present invention, and FIG. 1 is a sectional view taken along the line AA of FIG. The figure is a plan view (however, the illustration of the primary coil on the upper side is omitted),
FIG. 3 is a sectional view taken along the line BB of FIG. Figure 4 is 2
The following shows a secondary coil (corresponding to a secondary coil of a conventional current transformer and a high frequency heating coil), (a) is a plan view,
(B) is a sectional view taken along the line AA of (a), and (c) is B of (a).
-A sectional view taken along the line B, and (d) is a plan view of a practical secondary coil.

The present embodiment is a high frequency induction heating device for heating the outer peripheral surface of a stud pin W having a shape in which protrusions are formed on both end surfaces of a cylinder. As shown in FIGS. 1 and 2, 4 is placed on an insulating turntable 30 such as a glass laminate plate or a ceramic plate which is attached to a shaft 32 which is intermittently rotated by a driving device (not shown). 2 pieces of metal such as copper
The secondary coil 20 is fixed. 4 secondary coils 20 are axes
They are arranged at positions that are offset by 90 ° about 32.

As shown in FIG.
The secondary coil 20 has a substantially circular opening 21 (first opening) and a circular opening having a diameter larger than the diameter of the stud pin W.
22 (second opening) and a rectangular narrow gap 23 connecting the openings 21 and 22 are provided. The narrow gap 23 is usually filled with an insulator 25 such as Teflon as shown in FIG. 4 (d). The peripheral portion 21a of the opening 21 corresponds to the secondary coil of the conventional current transformer, and the peripheral portion 22a of the opening 22 corresponds to the conventional high frequency heating coil.

As shown in FIGS. 1 and 3, the opening of the secondary coil 20.
An insulative work placement table 31 made of ceramic or the like on which the stud pin W is placed is attached to a recess 34 provided on the surface of the turntable 30 below 22. Work placement table
A recess 31a into which a protrusion at the lower portion of the stud pin W is inserted is formed in the hole 31 so that the mounted stud pin W does not fall.

Above the peripheral portion 21a of the opening 21 of one secondary coil 20 (upper secondary coil 20 in FIG. 2) of the four secondary coils 20 and below the turntable 30, One to one
A secondary coil 10 is provided. The primary coil 10 is formed to have an opening 10a at the center so as to correspond to the shape of the peripheral portion 21a of the opening 21 of the secondary coil 20, and is arranged at a position facing the peripheral portion 21a. There is. The primary coil 10 is formed so as to cover a conductor 11 made of a good conductive metal and wound in multiple layers in a spiral shape with an insulator 13 in between, and a surface of the conductor 11 other than the surface facing the secondary coil 20. It has a core 14 made of ferrite or the like.

The conductor 11 has a hollow portion 12, through which a cooling liquid is circulated to cool the conductor 11. The primary coil 10 is attached to the insulating plate 15. Also, the lower one
One end and the other end of the secondary coil 10 are connected to one end of the high frequency power supply 100 and one end of the upper primary coil 10 via lead wires 101 and 102, respectively.
The other end of is connected to the other end of the high frequency power supply 100 via a lead wire 103. In this way, the primary coil is divided into two upper and lower sets that are connected in series, so that the primary coil as a whole can have a sufficiently large inductance.

As described above, the pair of primary coils 10 and the peripheral portion 21a of the opening 21 of the secondary coil 20 form a plane-opposed current transformer. Each primary coil 10 is wound so that magnetic flux is generated in the same direction when energized.

Next, the operation of this embodiment will be described.

First, the protrusion of the lower part of the stud pin W is inserted into the recess 31a of the work mounting table 31 in the opening 22 of the secondary coil 20 shown on the right side in FIG. 2 to mount the stud pin W on the work mounting table 31. Place. Then, the turntable 30 is rotated by 90 ° in the direction of arrow C by a turntable driving device (not shown) and then stopped. Then, the secondary coil 20 comes to the position of the secondary coil 20 shown above in FIG. At this time, as shown in FIG. 1, the outer peripheral portion 21a of the opening 21 of the secondary coil 20 is located between the pair of primary coils 10 and opposite to the primary coil 10. When a high-frequency current is passed from the high-frequency power source 100 to the primary coil 10 for a predetermined time in this state, as shown in FIG. The induced current i flows through the portion 22a. The induced current i causes an induced current to flow through the stud pin W arranged in the opening 22 to heat the stud pin W. Thus, after heating the stud pin W for a predetermined time, the power supply to the primary coil 10 is cut off. Then, after cooling liquid is sprayed onto the stud pin W from a jacket (not shown) to rotate the stud pin W, the turntable 30 is rotated by 90 ° in the direction of arrow C by a drive device (not shown) and then stopped. Then, the stud pin W is removed from the work mounting table 31 manually or by a machine.

Hereinafter, by repeating the above operation, a large number of stud pins W can be sequentially and automatically subjected to high frequency induction heating.

In the present embodiment, the turntable 30 is assumed to be entirely insulative, but the present invention is not limited to this, and only the periphery of the secondary coil 20 and other necessary parts are insulative, and the other parts are electrically conductive. You can also do it. Further, a core may be attached to the peripheral portion 21a of the opening 21 as in the case of the primary coil 10, or a cooling liquid may be circulated inside the secondary coil 20 for cooling.

<Effects of the Invention> As described above, the high-frequency induction heating method and apparatus of the present invention are substantially plate-shaped and have the first and second openings and the narrow gaps connecting these openings, and are radially arranged on the turntable. A work is installed in the second opening of a plurality of secondary coils, and the secondary coil and the turn are placed above one of the secondary coils and below the turntable, respectively. A pair of 1s fixedly arranged close to the table and formed to correspond to the shape of the peripheral portion of the first opening.
A secondary coil is arranged between the secondary coils, a pair of primary coils and the peripheral portion form a plane-opposing current transformer, and a heating coil is formed in the peripheral portion of the second opening, After the high-frequency current is passed through the primary coil to finish heating the work, the turntable is rotated to dispose the peripheral portion of the next secondary coil between the primary coils so that the second coil of the second secondary coil is The work set in the opening is heated.

Therefore, according to the high-frequency induction heating method and apparatus of the present invention, it is not necessary to move the current transformer up and down, and the structure of the high-frequency heating apparatus is simple and inexpensive. Further, the primary coil is composed of two primary coils, an upper primary coil and a lower primary coil.
Since it is composed of the secondary coil, it is possible to sufficiently increase the inductance of the entire primary coil. Therefore, even if the power applied to the primary coil has a low frequency, a high-density magnetic flux is generated and the work is Has the advantage that it can be sufficiently induction-heated.

[Brief description of drawings]

1 to 4 are drawings for explaining one embodiment of the present invention, in which FIG. 1 is a sectional view taken along the line AA of FIG. 2, and FIG. (The illustration of the primary coil is omitted), and FIG. 3 is a sectional view taken along the line BB of FIG.
FIG. 4 shows a secondary coil (corresponding to a secondary coil of a conventional current transformer and a high frequency heating coil), (a) is a plan view, (b) is a sectional view taken along the line AA of (a), ( 3C is a sectional view taken along the line BB in FIG. 3A, and FIG. 3D is a plan view of a practical secondary coil. FIG. 5 is an explanatory diagram of an example of a conventional high frequency induction heating device. 10 …… Primary coil, 20 …… Secondary coil, 21, 22 …… Opening, 21a, 22a …… Peripheral part, 23 …… Narrow gap, 30 …… Turntable, W …… Stud pin.

Claims (2)

[Claims] 1. A work is provided in a second opening of a plurality of secondary coils radially provided on a turntable, which is substantially plate-like and has first and second openings and a narrow gap connecting these openings. And a shape of a peripheral portion of the first opening, which is fixedly arranged close to the secondary coil and the turntable above and below the one secondary coil among the secondary coils, respectively. A secondary coil is disposed between a pair of primary coils formed so as to correspond to the above, and a pair of primary coils and the peripheral portion form a plane-opposing current transformer; and A heating coil is formed in the peripheral part of the opening, the high frequency current is passed through the primary coil to finish heating the work, and then the turntable is rotated to put the peripheral part of the next secondary coil between the primary coils. Place in the second opening of the secondary coil next High-frequency induction heating method characterized by heating the installed workpiece. 2. A plurality of substantially plate-shaped secondary coils radially provided on an insulating turntable, and one secondary coil above these secondary coils and below the turntable via the turntable. A pair of fixed primary coils is provided, and the secondary coil is provided with the first and second openings and a narrow gap connecting both the openings, and the primary coil is provided around the first opening. By forming the upper primary coil so as to face the peripheral portion so as to face the peripheral portion and the lower primary coil so as to face the peripheral portion and approach the turntable, A high-frequency induction heating apparatus, characterized in that a pair of primary coils and the peripheral portion form a plane-opposing current transformer, and a heating coil is formed in the peripheral portion of the second opening.