JP4999394B2 - Induction heating coil - Google Patents

Description

  The present invention relates to an induction heating coil that performs induction heating on an outer peripheral surface and one end surface of a cylindrical object to be heated at the same time.

  There is a technology that induces eddy current (electromagnetic induction) in this work by passing high-frequency current through an induction heating coil placed close to the object to be heated (work), and induction heating the work with its Joule heat. Widely known. In this technique, workpieces of various shapes are subjected to induction heating. An example of the workpiece is a cylindrical workpiece, and a technique is known in which the inner peripheral surface, the outer peripheral surface, and the end surface between them are simultaneously induction-heated (see, for example, Patent Document 1). ).

JP-A-11-199920

  According to said technique, since the heating area per unit time in the internal peripheral surface of a cylindrical workpiece | work, an outer peripheral surface, and an end surface is made equal, it is supposed that these surfaces can be heated uniformly. However, since the influence of heat conduction is not considered only by equalizing the heating area per unit time, the inner peripheral surface, outer peripheral surface, and end surface of the cylindrical workpiece may not be heated uniformly.

  An object of this invention is to provide the induction heating coil which can carry out the induction heating of the outer peripheral surface and one end surface of a cylindrical workpiece | work (to-be-heated material) simultaneously and uniformly in view of the said situation.

In order to achieve the above object, an induction heating coil of the present invention is an induction heating coil for induction heating the outer peripheral surface and one end surface of a cylindrical object to be heated at the same time.
(1) A ring-shaped induction heating coil for an outer peripheral surface arranged to surround the outer peripheral surface for induction heating the outer peripheral surface;
(2) A disc-shaped induction heating coil for one end surface that covers one end surface of the induction heating coil for the outer peripheral surface and a space surrounded by the one end surface, and a part of which is cut out in a fan shape,
(3) The induction heating coil for the outer peripheral surface is formed with two opposing portions that extend in the height direction, oppose each other and are electrically insulated, and each of these two opposing portions (4) Either one of the two fan-shaped straight line portions of the induction heating coil for one end face is electrically connected so as to overlap one end face of the two opposing portions , and the other is The outer peripheral surface induction heating coil overlaps and is electrically connected to one end surface, and the central angle of the portion cut out in the fan shape is 15 ° or more and 120 ° or less. A part of the one end surface is exposed .

here,
(5) The induction heating coil for one end face may be one in which the notched fan-shaped center is located inside the one end face of the article to be heated.

Also,
(6) The recessed part may be formed in the lower surface side part adjacent to the said induction heating coil for outer peripheral surfaces among the said induction heating coils for one end surface.

  In the induction heating coil according to the present invention, the high-frequency current supplied from the connection conductor connected to the high-frequency power source flows to the outer peripheral surface induction heating coil and also to the one end surface induction heating coil. An eddy current is generated on the outer peripheral surface of the object to be heated by the high frequency current flowing in the induction heating coil for the outer peripheral surface, and the outer peripheral surface of the object to be heated is heated by this eddy current. On the other hand, the current tends to flow through the shortest distance, and the linear part of the induction heating coil for one end face overlaps the opposite part of the induction heating coil for outer peripheral face. It flows mainly through two straight sides (two straight portions) cut out in a fan shape of the induction heating coil for one end face. As a result, an eddy current is generated on one end surface of the object to be heated, and the one end surface is induction heated. In this way, the outer peripheral surface and the one end surface of the object to be heated can be simultaneously and uniformly heated by the outer peripheral surface induction heating coil and the one end surface induction heating coil. In addition, since the one end surface induction heating coil covers the one end surface of the outer peripheral surface induction heating coil, a part of the coolant injected toward the outer peripheral surface is cooled to cool the outer peripheral surface of the object to be heated. It bounces back to the one end face induction heating coil and hits one end face of the object to be heated. For this reason, scattering of the coolant sprayed toward the outer peripheral surface is prevented, and not only the outer peripheral surface of the object to be heated but also one end surface can be efficiently and reliably cooled. As described above, according to the induction heating coil of the present invention, a heating layer having a uniform depth is formed on one end surface and the outer peripheral surface of the object to be heated, and this heating layer can be cooled efficiently and reliably. A quenching layer having a uniform depth can be formed on the object to be heated.

  The present invention has been realized in an induction heating coil that performs induction heating simultaneously on the outer peripheral surface and one end surface of a cylindrical object to be heated.

  An example of the induction heating coil of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view showing a state in which an induction heating coil is arranged to heat a cylindrical object to be heated. FIG. 2 is a plan view of FIG. 3 is a cross-sectional view taken along the line AA in FIG.

  The induction heating coil 10 is for inductively heating the outer peripheral surface WS and the one end surface WT of the cylindrical object to be heated W at the same time. The induction heating coil 10 includes a ring-shaped (annular) outer circumferential surface induction heating coil 20 disposed so as to surround the outer circumferential surface WS of the article to be heated W. The outer circumferential surface induction heating coil 20 is an outer circumferential surface. Inductively heat WS.

  The induction heating coil 20 for the outer peripheral surface is not a completely continuous ring shape, but is divided at a part thereof. In this divided portion, two opposing portions 22 and 24 that extend in the height direction (direction of arrow H) of the outer circumferential surface induction heating coil 20 and face each other are formed. The two opposing portions 22 and 24 are electrically insulated. Connection conductors 52 and 54 connected to the high frequency power supply 50 are connected to the two opposing portions 22 and 24, respectively.

  Moreover, the induction heating coil 10 includes an induction heating coil 30 for one end surface that is disposed close to the upper end of the one end surface WT of the article W to be heated. Is a disk-shaped one cut out in a fan shape. The one end face induction heating coil 30 is fixed to the outer peripheral face induction heating coil 20 so as to cover one end face 20T of the outer peripheral face induction heating coil 20 and a space surrounded by the one end face 20T.

  In a fan-shaped notch portion 32 (hereinafter referred to as a fan-shaped notch portion 32) formed in the one end surface induction heating coil 30, one end surface 20T of the outer circumferential surface induction heating coil 20 and one end surface WT of the object W to be heated. Is exposed. The center C of the fan-shaped notch 32 coincides with the center C of the disc-shaped induction heating coil 30 for one end face. That is, the center C of the fan-shaped notch portion 32 is located inside the one end surface WT of the article to be heated W. Further, the central angle θ of the fan-shaped notch portion 32 is preferably 15 ° or more and 120 ° or less. This is because the current tends to flow through the shortest distance, and when the central angle θ is less than 15 °, the high-frequency current flows too much through the straight portions L1 and L2 (described later) of the one end face induction heating coil 30. The balance with the high-frequency current flowing through the outer peripheral surface induction heating coil 20 is lost, and the outer peripheral surface WS and the one end surface WT of the article W to be heated cannot be heated to a uniform depth, and the central angle θ is 120. When the temperature exceeds 60 °, high-frequency current flows in a portion away from the fan-shaped notch portion 32 of the one end face induction heating coil 30, so that the outer peripheral surface WS and the one end surface WT of the object W to be heated have a uniform depth. This is because it cannot be heated.

  Two linear portions L1 and L2 are formed in a portion corresponding to the straight side of the fan-shaped notch portion 32 in the one end surface induction heating coil 30, and the linear portion L2 overlaps the end surface 24T of the facing portion 24. Electrically connected. That is, a portion corresponding to the straight line portion L <b> 2 of the fan-shaped notch portion 32 in the one end face induction heating coil 30 is electrically connected to the connecting conductor portion 54.

  As shown in FIG. 3, a recess 26 is formed in the lower surface side portion adjacent to the outer peripheral surface induction heating coil 20 in the lower surface of the one end surface induction heating coil 30. Due to the concave portion 26, the corner of the article W to be heated (the boundary portion between the outer peripheral surface WS and the one end surface WT) is farther from the one end surface induction heating coil 30 than the one end surface WT. For this reason, the overheating (overheating) of the corner | angular part of the to-be-heated material W is prevented.

  When simultaneously inductively heating the outer peripheral surface WS and the one end surface WT of the object to be heated W, a high-frequency power source while rotating the object to be heated W around the axis C together with the support base 60 on which the object to be heated W is placed. Power is supplied from 50 to the induction heating coil 10 via the connecting conductor portions 52 and 54. The frequency of the high frequency power supply 50 is 25 kHz, for example, and the output is 250 kW.

  Here, when a high-frequency current flows in the direction of arrow A as shown in FIG. 2, the current tends to flow through the shortest distance. Therefore, in the induction heating coil 30 for one end surface, the high-frequency current passes through the straight line portion L1 from the connecting conductor portion 54. Flows to the straight line portion L2 and flows to the connecting conductor portion 52 through the induction heating coil 20 for the outer peripheral surface. Further, in the outer circumferential surface induction heating coil 20, a high-frequency current flows uniformly from the connection conductor portion 54 through the entire outer circumferential surface induction heating coil 20 to the connection conductor portion 52. An eddy current is generated on the outer peripheral surface WS of the object to be heated W by the high-frequency current flowing in the outer peripheral surface induction heating coil 20, and the outer peripheral surface WS of the object to be heated W is heated by this eddy current. On the other hand, the high-frequency current flowing through the one end face induction heating coil 30 mainly flows through the two linear portions L1 and L2 of the one end face induction heating coil 30 as described above. As a result, an eddy current is generated in the one end surface WT of the article to be heated W, and the one end surface WT is inductively heated. Thus, the outer peripheral surface WS and the one end surface WT of the article W to be heated can be simultaneously and uniformly heated by the outer peripheral surface induction heating coil 20 and the one end surface induction heating coil 30.

  The one end face induction heating coil 30 covers one end face of the outer peripheral face induction heating coil 20, so that the cooling injected to the outer peripheral face WS to cool the outer peripheral face WS of the article W to be heated is performed. A part of the liquid is bounced back to the one end face induction heating coil 30 and hits one end face WT of the article W to be heated. For this reason, scattering of the coolant injected toward the outer peripheral surface WS is prevented, and not only the outer peripheral surface WS but also the one end surface WT can be efficiently and reliably cooled. As described above, according to the induction heating coil 10, a heating layer having a uniform depth is formed on the one end surface WT and the outer peripheral surface WS of the object to be heated W, and this heating layer can be cooled efficiently and reliably. A quenching layer having a uniform depth can be formed on the heated object W.

It is a perspective view which shows the state which has arrange | positioned the induction heating coil in order to heat a cylindrical to-be-heated material. It is a top view of FIG. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2.

DESCRIPTION OF SYMBOLS 10 Induction heating coil 20 Induction heating coil 30 for outer peripheral surfaces Induction heating coil 32 for one end surface Fan-shaped notch 50 High-frequency power supply W
WS Outer peripheral surface WT One end surface

Claims (2)

In the induction heating coil that simultaneously heats the outer peripheral surface and one end surface of the cylindrical object to be heated,
A ring-shaped induction heating coil for an outer peripheral surface, which is arranged so as to surround the outer peripheral surface, for induction heating the outer peripheral surface;
The outer circumferential surface induction heating coil covers one end surface and a space surrounded by the one end surface, and includes a disk-shaped induction heating coil for one end surface, part of which is cut out in a fan shape,
The outer circumferential surface induction heating coil is formed with two opposing portions that extend in the height direction, face each other and are electrically insulated, and each of the two facing portions is connected to a high-frequency power source. Connected to the connected conductor portion,
Either one of the two fan-shaped straight line portions of the induction heating coil for one end face is electrically connected so as to overlap one end face of the two opposing portions , and the other is It is electrically connected to one end surface of the outer peripheral surface induction heating coil,
The induction heating coil is characterized in that a central angle of the fan-shaped part is 15 ° or more and 120 ° or less, and a part of one end face of the outer peripheral surface induction heating coil is exposed from the part . The induction heating coil according to claim 1, wherein a concave portion is formed in a lower surface side portion adjacent to the outer peripheral surface induction heating coil of the one end surface induction heating coil.

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