JPH06281079A - Work coil for high-frequency power supply - Google Patents

Abstract

PURPOSE:To improve attaching/detaching performance, reduce leakage flux, and improve heating efficiency, by providing a work coil which generates high- frequency current in a magnetic alloy heater by induction with a coil mat which is curved in a circumferential direction. CONSTITUTION:This work coil 10 for high-frequency power supply, which is used for fusion of a plastic pipe or the like, contains a coil mat 12 of roughly C-shape. The coil mat 12 is provided with a core 14 made of heat resistant resin such as polycarbonate, a loop which consists of an inducting body 16 is formed on its external surface, and a ferritic layer 22 and a casing 24 made of aluminum or the like are formed at its outside. In connecting pipes 38, 38 with each other, the respective pipes 38 are inserted in the socket of a joint 30 formed with a magnetic alloy heater 36 on its internal circumferential surface side, and the inducing body 16 is energized through terminals 30a, 30b by a high-frequency power supply 34, so that the heater 36 is inductively-heated to fusion-connect both the coupler and the pipes 30, 38 with each other at their connected surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work coil for a high frequency power source, and more particularly to a work coil for a high frequency power source used for fusing plastic pipes or the like utilizing high frequency induction heating.

[0002]

2. Description of the Related Art An example of a work coil for a high frequency power source for fusion bonding plastic pipes using high frequency induction heating is disclosed in International Publication WO92 / 15182. This work coil has a joint sandwiched between two coil mats.

[0003]

The conventional work coil has a problem that it is difficult to manufacture because it is necessary to form two coil mats. Further, since the entire apparatus is large and the joint is sandwiched by two coil mats, there is a problem that the detachability of the joint is poor.

Therefore, a main object of the present invention is to provide a work coil for a high frequency power source which can be easily manufactured and can be easily attached and detached.

[0005]

A first aspect of the present invention is a work coil for a high frequency power source for producing a high frequency current by induction in a magnetic alloy heater provided at a joint portion of synthetic resin, which has a predetermined loop. A work coil for a high-frequency power supply, which is provided with one coil mat including a wound conductor, and the coil mat is wound in the circumferential direction.

A second aspect of the present invention is a work coil for a high frequency power source for generating a high frequency current by induction in a magnetic alloy heater provided at a joint of synthetic resin, which is a conductor wound in a predetermined loop. A work coil for a high-frequency power supply, comprising: a coil mat containing the above; and a ferrite layer formed outside the coil mat. The third invention is
A work coil for a high-frequency power source for generating a high-frequency current by induction in a magnetic alloy heater provided at a joint of synthetic resin, the coil mat including conductors forming first and second portions having different diameters. It is a work coil for a high frequency power supply.

A fourth aspect of the present invention is a work coil for a high frequency power source for generating a high frequency current by induction in a magnetic alloy heater provided at a joint portion of synthetic resin, the first part extending in the circumferential direction and the axial direction. A work coil for a high-frequency power source, comprising a coil mat including a conductor forming a loop with a second portion extending to the first portion, and the first portion and the second portion formed in the same cylindrical surface.

[0008]

In the first invention, since only one coil mat needs to be formed, it can be easily manufactured. Further, if the coil mat is formed in a C shape or a U shape, it can be easily attached and detached around the joint. In the second invention, since the ferrite layer is formed outside the coil mat, the magnetic flux can be guided into the ferrite layer. Therefore, the leakage magnetic flux can be reduced.

The third aspect of the invention can be applied to two types of joints having different diameters by selecting and using either the first portion or the second portion having different diameters. Fourth
In the invention described above, since the first portion extending in the circumferential direction and the second portion extending in the axial direction of the loop formed by the conductor are formed in the same cylindrical surface, the size can be reduced.

[0010]

According to the first invention, it is possible to easily manufacture
Moreover, the detachability can be improved. According to the second aspect of the present invention, since the leakage magnetic flux can be reduced, the heating efficiency can be improved. According to the third invention, since it can be applied to two types of joints having different diameters,
The workability can be improved.

According to the fourth invention, the size can be reduced, so that the cost can be reduced and the workability can be improved. The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0012]

1 and 2, a work coil 10 for a high frequency power source of this embodiment includes one coil mat 12 (FIG. 2) having a substantially C shape. The coil mat 12 is, for example, a core 1 made of a heat resistant resin such as polycarbonate.
4 and on the outer surface of the core 14, a conductor 16 forms a loop 18 or 20, for example as shown in FIG. 3 or 4. Then, a ferrite layer 22 is formed outside the coil mat 12 (conductor 16),
A casing 24 made of aluminum or the like is formed outside the ferrite layer 22 so as to cover the coil mat 12 and the ferrite layer 22. Ferrite layer 22
In addition to being formed by sintering, attaching a ferrite tile, or the like, it may be formed as a synthetic resin layer mixed with ferrite powder. The casing 24 is divided into a first portion 24a and a second portion 24b so that the opening 26 (FIG. 1) of the coil mat 12 can be enlarged.
4a and the second portion 24b are connected via a hinge 28. However, when the opening 26 is wider than the outer diameter of the joint 30 (FIG. 2), the casing 24 does not necessarily have to be divided.

Terminals 30a and 30b, each of which is connected to the end of the conductor 16, are formed on the upper portion of the casing 24, and a handle 32 is provided between both terminals. And
A high frequency power supply 34 (FIG. 2) is connected to the terminals 30a and 30b. At the time of joining, as shown in FIG. 2, a joint 30 having a magnetic alloy heater 36 provided in the vicinity of the inner peripheral surface thereof is prepared, and a pipe 38 to be joined is inserted into a socket of the joint 30 to insert a workpiece into the joint 30. Cover the coil 10. Then, the switch of the high frequency power supply 34 is turned on to energize the conductor 16, thereby applying a high frequency current to the heater 36. Then, the heater 36 rapidly generates heat in the skin portion where the current is concentrated due to the skin effect. When the temperature of the heater 36 rises to reach the Curie temperature, the magnetic permeability of the heater 36 is drastically reduced, and the skin current hardly flows.
The fever of is greatly reduced. Heater 3 by heat radiation
When the temperature of 6 decreases, the heater 36 again generates heat due to the skin current. In this way, since the heater 36 is maintained at the predetermined Curie temperature, the bonding surface is heated to the predetermined Curie temperature or its vicinity, that is, the optimum fusion temperature,
Fused.

The inventors applied the work coil 10 to the magnetic alloy heater 40 (φ60) as shown in FIGS. 5 and 6 and measured the temperature change of each part a to e, thereby The practicality was verified. FIG. 7 is a graph in which the horizontal axis represents the energization time and the vertical axis represents the measured temperatures of the respective portions a to e. From this graph, it was confirmed that the entire magnetic alloy heater 40 could be heated almost uniformly even if the open portion 26 was provided.

According to this embodiment, since the coil mat 12 is provided with the opening 26, the work coil 10 can be easily attached and detached and the workability can be improved. Also,
Since the ferrite layer 22 is formed outside the coil mat 12, the magnetic flux can be introduced into the ferrite layer 22. Therefore, the leakage magnetic flux can be reduced,
Thereby, efficiency can be improved and radiation noise can be reduced.

When the loop 18 (FIG. 3) is formed, the magnetic flux may be canceled at the central portion thereof, so that the central portion A (FIG. 2) of the work coil 10 has a higher relative magnetic permeability than the other portions. It is also possible to use a high ferrite and concentrate the magnetic flux in that portion to prevent the cancellation of the magnetic flux. By the way, the relative magnetic permeability of the central portion A is 25
The relative permeability of other portions was set to about 250.

Further, a stopper 42 as shown in FIG. 8 or a stopper 44 as shown in FIG. 9 may be formed so that the work coil 10 can be reliably positioned on the pipe 38 to be joined. In addition, for example, as shown in FIG. 10, the lower end of the work coil 10 is folded back to the outside, and the loop 18 (FIG. 3) or the loop 20 (FIG. 4) is folded into this folded portion 46.
Disturbance of the magnetic field may be prevented by disposing a portion extending in the axial direction of.

The shape of the work coil 10 is not limited to the C shape as in the above-mentioned embodiment, but may be formed in a U shape as shown in FIG. 11 or 12, for example. Work coil 4 of another embodiment shown in FIG.
Reference numeral 8 is a body 50 made of a soft material such as ferrite rubber, in which a loop 18 (FIG. 3) or 20 (FIG. 4) is formed, and is used by bending it to an arbitrary curvature.

In each of the above embodiments, the conductor 16
Although the case where the loop 18 (FIG. 3) or 20 (FIG. 4) is formed by the above is shown, when applied to the joint 52 having the receiving port on only one side thereof, as shown in FIG. 14, the loop 18 or Instead of 20, loops 54 or 56 may be formed as shown in FIG. 15 or FIG. 16, for example. Also in this case, it is possible to prevent the magnetic flux from being canceled by using ferrite having a higher relative magnetic permeability than others in the intermediate portion B (FIG. 14) between the work portion and the waste winding portion. In addition, the loop 56 is a waste winding portion C (FIG. 16).
It is a double wound.

The work coil 58 of another embodiment shown in FIGS. 17 and 18 is to be applied to two types of single-sided receiving joints having different diameters, and a first portion 60 and a second portion 62 having different calibers. A coil mat 64 having The coil mat 64 includes a core 66, and the conductor 16 forms a loop 18 or 20 as shown in FIG. 3 or 4 on the outer surface of the core 66. The ferrite layer 22 is formed on the outside of the coil mat 64 as in the above-described embodiment (FIG. 2), and the casing 24 is formed on the outside of the ferrite layer 22.

At the time of joining, either the first portion 60 or the second portion 62 is selected according to the diameter of the joint to be joined. That is, when applied to the large-diameter joint 68, as shown in FIG. 17, it is fused using the first portion 60, and when applied to the small-diameter joint 70, as shown in FIG. It is fused using the second portion 62. When applied to the small diameter joint 70, the adapter 72 is attached to the inner surface of the first portion 60.

According to this embodiment, since one work coil 58 can be applied to two types of single-sided receiving joints having different diameters, it is not necessary to prepare a work coil for each type of joint, and workability can be improved. In this embodiment, one C-shaped or U-shaped coil mat as described above may be used, or a structure in which two coil mats sandwich a joint as in the prior art.

The above-described idea of reducing the loss of magnetic flux by forming the ferrite layer on the outside of the coil mat can be directly applied to the conventional work coil disclosed in WO92 / 15182. Further, it can be applied to a work coil 78 (ferrite layer not shown) having two coil mats 74 and 76 as shown in FIG. In the work coil 78,
Since the first portion extending in the circumferential direction and the second portion extending in the axial direction of the loop formed by the conductor 16 are formed in the same cylindrical surface, the portion extending in the axial direction of the conductor is formed in the cylindrical surface. There is an advantage that the size can be reduced as compared with the conventional work coil removed from the inside.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing the embodiment of FIG.

3 is an illustrative view showing a loop applied to the embodiment in FIG. 1. FIG.

4 is an illustrative view showing another loop applied to the embodiment in FIG. 1. FIG.

FIG. 5 is an illustrative view showing an experimental method for verifying the practicality of the embodiment of FIG.

FIG. 6 is an illustrative view showing an experimental method for verifying the practicality of the embodiment of FIG.

FIG. 7 is a graph showing the experimental results of FIG.

8 is a perspective view showing a state in which a stopper is provided in the embodiment of FIG.

9 is a perspective view showing a state in which a stopper is provided in the embodiment of FIG.

10 is a perspective view showing a state in which a folded portion is provided in the embodiment of FIG.

FIG. 11 is a perspective view showing a state where the whole is formed in a U shape.

12 is a perspective view showing a state in which a folded portion is formed in the embodiment of FIG.

FIG. 13 is an illustrative view showing a work coil including a main body formed of a soft material.

FIG. 14 is an illustrative view showing a state in which the embodiment of FIG. 1 is applied to a single receiving joint.

FIG. 15 is an illustrative view showing a loop applied in FIG. 14;

16 is an illustrative view showing another loop applied in FIG. 14. FIG.

FIG. 17 is an illustrative view showing another embodiment of the present invention.

FIG. 18 is an illustrative view showing a state in which the embodiment of FIG. 16 is applied to a small diameter joint.

FIG. 19 is a perspective view showing a work coil having two coil mats.

[Explanation of symbols]

 10, 48, 58 ... Work coil 12 ... Coil mat 14 ... Core 16 ... Conductor 18, 20, 54, 56 ... Loop 22 ... Ferrite layer 24 ... Casing 26 ... Opening portion 30, 52, 68, 70 ... Joint 36, 40 ... Magnetic alloy heater

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kozo Nishikawa 1-1-1 Hama, Amagasaki City, Hyogo Prefecture Kubota Technology Development Laboratory Co., Ltd. (72) Inventor Masayuki Kanda 1-1-1 Hama, Amagasaki City, Hyogo Prefecture Kubota Technology Development Laboratory

Claims (6)

[Claims] 1. A work coil for a high frequency power source for generating a high frequency current by induction in a magnetic alloy heater provided at a joint of synthetic resin, comprising one conductor including a conductor wound in a predetermined loop. A work coil for a high frequency power supply, comprising a coil mat, and the coil mat being wound in a circumferential direction. 2. The work coil for a high frequency power source according to claim 1, wherein the coil mat is formed only in a part in the circumferential direction. 3. A work coil for a high-frequency power source for generating a high-frequency current by induction in a magnetic alloy heater provided at a joint of synthetic resin, the coil mat including a conductor wound in a predetermined loop. ,
And a work coil for a high frequency power supply, comprising a ferrite layer formed on the outside of the coil mat. 4. The work coil for a high frequency power source according to claim 3, wherein a part of the ferrite layer has a relative magnetic permeability higher than that of the other part, and a magnetic flux is guided to the part. 5. A work coil for a high-frequency power source for generating a high-frequency current by induction in a magnetic alloy heater provided at a joint of synthetic resin, the conductor forming first and second portions having different diameters. A work coil for a high frequency power supply, which includes a coil mat including: 6. A work coil for a high frequency power source for generating a high frequency current by induction in a magnetic alloy heater provided at a joint of synthetic resin, the first coil extending in a circumferential direction and the second coil extending in an axial direction. A work coil for high-frequency power supply, comprising a coil mat including a conductor that forms a loop with the portion, and wherein the first portion and the second portion are formed in the same cylindrical surface.