JP3868651B2 - Induction heating coil - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating coil that induction-heats a long material while relatively moving along the longitudinal direction of the long material.
[0002]
[Prior art]
Conventionally, induction hardening that hardens a surface layer of a workpiece (workpiece) such as steel using induction heating has been widely used. In this induction hardening, an induction heating coil is used when heating the workpiece. For example, when induction-hardening a plurality of long materials as an object to be processed, the induction heating coil is fixed, and the plurality of long materials are sequentially moved in the longitudinal direction with the induction heating coil. Heat, then quench and cure.
[0003]
When a plurality of long materials are continuously heated in this way, an induced current (eddy current) flows also on the end surfaces of the long material at both ends in the longitudinal direction among the side walls of the long material. For this reason, the induced current flowing in the surface layer of the side wall at both ends in the longitudinal direction is reduced by the amount of the induced current flowing in the end face, and this surface layer is hardly heated to the quenching temperature. In this case, the surface layer on the side wall in the vicinity of both ends in the longitudinal direction is not sufficiently cured, and so-called “burn-out” occurs at both ends in the longitudinal direction.
[0004]
Such “burn-out” is prominently generated at the end of the long material on the heating start side. In addition, “quenching” occurs not only when a plurality of long materials are continuously induction-hardened, but also at both ends when a single long material is induction-hardened. Furthermore, it may occur at both ends of the tooth tip when the gear tooth tip is induction-hardened.
[0005]
By the way, when the long material is induction-hardened, this part is usually heated to the quenching temperature by using an induction heating coil that generates an induction current in the part to be hardened. In this case, not only the part to be cured but also other parts are heated to the quenching temperature, and this other part may be cured.
[0006]
[Problems to be solved by the invention]
When a plurality of long materials with the above-mentioned “burn-out” are connected to each other and used longer, the longitudinal direction of each long material is used to remove the uncured portion (burn-out portion). Cut both ends. Therefore, there is a problem that the cost for the cutting work is required, and the material corresponding to both ends in the longitudinal direction is wasted.
[0007]
In addition, when the gear tip is induction hardened, if "burn-out" occurs at both ends of the tooth tip, the gear life is shortened due to pitching at both ends of the tooth tip during use of the gear. There's a problem.
[0008]
By the way, as described above, when the long material is induction-quenched, not only the portion to be cured but also other portions may be heated to the quenching temperature and cured. In this case, processing such as drilling may be applied to the other cured part. However, there is a problem in that the hardened other part is difficult to process, and the processing work is troublesome.
[0009]
In view of the above circumstances, the present invention is an induction heating coil that can sufficiently heat only one end of a long material side wall from one end to the other end to prevent “burn-out” and heat only a desired portion. The purpose is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an induction heating coil according to the present invention induction-heats a long material while relatively moving along the longitudinal direction of the long material in which a groove extending in the longitudinal direction is formed on a side wall. In induction heating coil,
(1) a first conductor portion extending in a predetermined direction;
(2) a second conductor portion extending in parallel with the first conductor portion;
(3) A "<"-shaped third conductor extending in a direction substantially orthogonal to the first and second conductor portions, electrically connecting one end of the first conductor portion and one end of the second conductor portion. And a section.
[0011]
here,
(4) The first conductor portion extends in the longitudinal direction along the end portion in the vicinity of the end portion in the width direction orthogonal to the longitudinal direction, of the upper wall of the long material.
(5) The second conductor portion extends in the vicinity of the groove along the groove,
(6) The third conductor portion may be disposed away from the long material.
[0012]
The induction heating coil
(7) You may provide the 4th conductor part electrically connected to the said 2nd conductor part located in the vicinity of the lower wall of the said elongate material.
[0013]
further,
(8) The long material has grooves extending in the longitudinal direction formed on the left and right side walls of the long material,
(9) Each of the first, second, and third conductor portions may be a pair of facing each other.
[0014]
Furthermore,
(10) The fourth conductor portion may be composed of a pair of conductors arranged in the vicinity of both ends in the width direction orthogonal to the longitudinal direction, of the lower wall of the long material.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The induction heating coil of the present invention will be described below with reference to the drawings.
[0016]
An embodiment of the induction heating coil according to the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a perspective view showing an embodiment of the induction heating coil, and FIG. 2 is a perspective view schematically showing the induction heating coil of FIG.
[0018]
The induction heating coil 10 includes a first conductor portion 20 extending in a predetermined direction (here, the longitudinal direction of the long material and also the conveying direction of the long material as will be described later), and the first conductor portion. 20 and a second conductor portion 30 extending in parallel. One end 20 a of the first conductor portion 20 and one end 30 a of the second conductor portion 30 are electrically connected via a “<”-shaped third conductor portion 40. The “<”-shaped third conductor part 40 is disposed on a plane orthogonal to the first and second conductor parts 20, 30. The other end 20b of the first conductor portion 20 is connected to a high frequency power source (not shown).
[0019]
The other end 30b of the second conductor portion 30 is electrically connected to one end 50a of the conductor portion 50 that extends perpendicularly to the first and second conductor portions 20 and 30 and away from them. The other end 50 b of the conductor portion 50 is electrically connected to the other end 60 b of the conductor portion 60 that is bent at a right angle therefrom and extends in parallel to the second conductor portion 30. One end 60 a of the conductor portion 60 is electrically connected to one end 70 a of the conductor portion 70 extending in a direction orthogonal to both the conductor portions 50 and 60.
[0020]
The other end 70 b of the conductor part 70 is electrically connected to one end 80 a of the fourth conductor part 80, and the fourth conductor part 80 extends in parallel to the first and second conductor parts 20 and 30. The above-described four conductor portions 20, 30, 60, 80 have substantially the same length. The other end 80 b of the fourth conductor part 80 is electrically connected to one end 90 a of the conductor part 90 extending in parallel with the conductor part 70. When the plane passing through the center of the conductor part 90 (the center of the one end 90a and the other end 90b) is made symmetrical, the induction heating coil 10 includes the first conductor part 20, the second conductor part 30, The first conductor part 120, the second conductor part 130, the third conductor part 140, and the conductor part that are symmetrical with the third conductor part 40, the conductor part 50, the conductor part 60, the conductor part 70, and the fourth conductor part 80. 150, the conductor part 160, the conductor part 170, and the 4th conductor part 180 are formed. These conductor portions 120, 130, 140, 150, 160, 170, 180 face the corresponding conductor portions 20, 30, 40, 50, 60, 70, 80, respectively.
[0021]
The induction heating coil 10 is fixed to an insulating plate (baking material) 100. A rectangular hole 102 is formed in the central portion of the insulating plate 100, and a long material (object to be processed) 200 (see FIG. 5 and the like) passes through the hole 102. As shown in FIG. 3A, when the long material 200 passes through the hole 102 and is conveyed in the direction of arrow A (see FIG. 5), the long material 200 in the upper wall 202 of the long material 200. First conductor portions 20 and 120 extend in the longitudinal direction along both end portions 202a in the vicinity of both end portions 202a in the width direction orthogonal to the longitudinal direction (arrow A direction), and eddy currents are generated in both end portions 202a. It will be.
[0022]
As shown in FIG. 5, a groove 206 extending in the longitudinal direction is formed on the side wall 204 of the long material 200. When the long material 200 passes through the hole 102 and is conveyed in the direction of arrow A (see FIG. 5), the second conductor portions 30 and 130 extend along the groove 206 as shown in FIG. An eddy current is generated on the side surface of the groove 206. In addition, since the 3rd conductor parts 40 and 140 are arrange | positioned so that it may distance from the elongate material 200, an eddy current hardly arises in the elongate material 200 by the alternating current which flows through this 3rd conductor parts 40 and 140. FIG.
[0023]
With reference to FIGS. 3 to 5, the eddy current generated in the long material 200 by the induction heating coil 10 will be described in comparison with a conventional induction heating coil.
[0024]
FIG. 3 shows the induction heating coil arranged facing the side wall of the long material, (a) is a transverse sectional view showing the case of the induction heating coil of the present invention, and (b) is the case of the conventional induction heating coil. FIG. FIG. 4 shows the position of the side wall of the long material and the induction heating coil, (a) is a side view showing the outline in the case of the induction heating coil of the present invention, and (b) is the outline in the case of the conventional induction heating coil. The eddy current is schematically shown by a two-dot chain line. FIG. 5 schematically shows eddy currents generated in a long material, (a) is a perspective view when the induction heating coil of the present invention is used, and (b) is a case when a conventional induction heating coil is used. It is a perspective view, and an eddy current is typically shown by a two-dot chain line.
[0025]
As described above, a groove 206 extending in the longitudinal direction (arrow A direction) of the long material 200 is formed on the side wall 204 of the long material 200 that is a workpiece (not shown in FIG. 4). . When the side wall 204 of the long material 200 is heated using the induction heating coil 10 of the present invention, the first conductor portions 20 and 120 of the induction heating coil 10 have the width of the upper wall 202 as shown in FIG. It is located in the vicinity of both ends 202a in the direction. Further, the second conductor portions 30 and 130 of the induction heating coil 10 are located in the vicinity of the groove 206. Further, the fourth conductor portions 80 and 180 are located in the vicinity of both end portions 208 a in the width direction of the lower wall 208. Note that the third conductor portions 40 and 140 are separated from the side wall 204.
[0026]
While maintaining the positional relationship between the long material 200 and the induction heating coil 10 as described above, the long material 200 is transported at a predetermined speed in the longitudinal direction (direction perpendicular to the paper surface of FIG. 3). During this conveyance, the induction heating coil 10 is supplied with, for example, a high-frequency power of 75 kW having a voltage of 360 V and a frequency of 5.8 kHz.
[0027]
On the other hand, as shown in FIG. 3B, the conventional induction heating coil 300 includes a pair of “L” -shaped conductor portions 302 and 304 facing each other, and each of the conductor portions 302 and 304 is electrically connected. It is connected. When the side wall 204 of the long material 200 is heated using the conventional induction heating coil 300, the conductor portion 30 is separated from the groove 206 of the long material 200 by a predetermined interval as shown in FIG. The long material 200 is transported at a predetermined speed in the longitudinal direction. During this conveyance, the induction heating coil 300 is supplied with, for example, a high-frequency power of 75 kW having a voltage of 360 V and a frequency of 5.8 kHz.
[0028]
When the long material 200 is induction-heated using the induction heating coil 10 of the present invention as described above, the eddy current 12 generated in the long material 200 and the long material 200 using the conventional induction heating coil 300 are used. FIG. 4 and FIG. 5 show a comparison with the eddy current 14 generated in the long material 200 when induction heating is performed.
[0029]
When the induction heating coil 10 of the present invention is used, as shown in FIGS. 4A and 5A, the long material 200 is dispersed on both ends 202a of the upper wall 202 and the side surfaces of the grooves 206. Eddy current 12 is generated. Thus, since the eddy current 12 is dispersed so as to be generated only in the heated portion, and no eddy current is generated in the portion that is not desired to be cured, this portion is hardly heated. Further, such dispersed eddy current 12 has good heating efficiency in the longitudinal direction. For this reason, even the longitudinal end portion 209 of the long material 200 is sufficiently heated to the same extent as the longitudinal central portion 207.
[0030]
That is, the side wall 204 of the long material 200 can be sufficiently heated from one end to the other end in the longitudinal direction. Therefore, when the power condition is set so that both end portions 202a of the long material 200 and the side surfaces of the grooves 206 are heated to the quenching temperature, the corresponding portions of the longitudinal end portions 209 are also heated to the quenching temperature. Is done. For this reason, when the heated portion is rapidly cooled immediately after heating, both the end portions 202a of the long material 200 and the side surfaces of the grooves 206 and the portions of the longitudinal end portions 209 corresponding thereto are uniformly cured, and "burn-out" is caused. It can be lost.
[0031]
Moreover, the eddy current 13 is generated in the width direction both ends 208a of the lower wall 208 of the long material 200 by the alternating current flowing in the fourth conductor portions 80 and 180, and this portion is heated to the quenching temperature. If this part is cooled immediately after heating, it hardens. Although deformation may occur due to this hardening, this deformation also occurs due to the hardening of the side surfaces of both end portions 202 a and the groove 206. Both deformations cancel each other out, and the deformation of the long material 200 as a whole is reduced as compared with the case where the both ends 208a in the width direction are not cured.
[0032]
On the other hand, when the conventional induction heating coil 300 is used, as shown in FIGS. 4B and 5B, the side wall 204 of the long material 200 has an eddy current 14 spreading over the entire side wall 204. Arise. Such an eddy current 14 has poor heating efficiency. For this reason, the longitudinal direction end portion 209 of the long material 200 is not heated as much as the longitudinal direction central portion 207. That is, the heating temperature is different between the longitudinal end portion 209 of the side wall 204 of the long material 200 and the other portions. Accordingly, when the power condition is set so that the longitudinal center portion 207 is heated to the quenching temperature, the longitudinal end portion 209 is not easily heated to the quenching temperature. For this reason, even if the heated portion is rapidly cooled immediately after heating, there is a possibility that “burn-out” may occur at the longitudinal end portion 209.
[0033]
Referring to FIGS. 6 and 7, when a long material is induction-quenched using the induction heating coil of the present invention and the conventional induction heating coil, the hardness distribution at the longitudinal center and the hardness at the longitudinal end are as follows. Compare the distribution.
[0034]
FIG. 6 schematically shows a quenching pattern of the longitudinal end portion of the long material 200, (a) is a schematic diagram showing a quenching pattern when the induction heating coil of the present invention is used, and (b). These are the schematic diagrams which show a quenching pattern when the conventional induction heating coil is used. FIG. 7 is a graph showing the hardness distribution in the c, d, e, and f directions in FIG. 6, (a) is a graph when the induction heating coil of the present invention is used, and (b) is a conventional graph. It is a graph when an induction heating coil is used.
[0035]
The material of the long material 200 is equivalent to S55C (JIS standard), and has a length of 900 mm and a side wall width W of 70 mm. The heating conditions were a voltage of 360 V, a frequency of 5.8 kHz, and a high frequency power of 75 kW. Moreover, the conveyance speed (feeding speed) of the long material 200 was 6.5 mm / second. The long material 200 may be fixed and the induction heating coils 10 and 300 may be moved. The long material 200 and the induction heating coils 10 and 300 may be relatively moved. do it.
[0036]
When the induction heating coil 10 of the present invention is used, the quenching pattern of the longitudinal end portion 209 of the long material 200 is as shown in FIG. This quenching pattern was also the same in the longitudinal center portion 207 of the long material 200 (see FIG. 4A). Further, a uniform hardness distribution as shown in FIG. 7A was obtained at both the longitudinal end portion 209 and the longitudinal center portion 207 of the long material 200. That is, when the induction heating coil 10 of the present invention was used, a uniform quenching pattern and a uniform hardness distribution were obtained at both the longitudinal end 209 and the longitudinal center 207 of the long material 200. .
[0037]
On the other hand, when the conventional induction heating coil 300 is used, the quenching pattern of the longitudinal end portion 209 of the long material 200 is as shown in FIG. 6B, and the quenching pattern of the longitudinal center portion 207 is illustrated in FIG. 6 (a). Further, the hardness distribution at the longitudinal end portion 209 of the long material 200 is as shown in FIG. 7B, and the hardness distribution at the longitudinal center portion 207 is as shown in FIG. 7A. It was. That is, when the conventional induction heating coil 300 is used, the quenching pattern and the hardness distribution are different between the longitudinal end portion 209 and the longitudinal center portion 207 of the long material 200, and "burning out" occurs. did.
[0038]
【The invention's effect】
As described above, when a long material is heated using the induction heating coil of the present invention, for example, the first conductor portion is located near the end in the width direction orthogonal to the longitudinal direction on the upper wall of the long material. Is disposed so as to extend along the longitudinal direction, and the second conductor portion is disposed so as to extend in the vicinity of the groove along the groove. Further, the “<”-shaped third conductor portion is arranged so as to be away from the long material. When the first, second, and third conductor portions are arranged in such a state and an alternating current is passed through them, the first conductor portion is located near the end portion in the width direction of the upper wall. A strong eddy current flows through this end. In addition, since the second conductor portion extends along the groove, a strong eddy current flows also in the vicinity of the groove. On the other hand, since the third conductor portion is disposed away from the long material, an eddy current hardly occurs in the long material due to the alternating current flowing through the third conductor portion. As a result, the eddy current flows in a distributed manner in the vicinity of the end portion in the width direction of the upper wall and in the vicinity of the groove, and these portions are intensively heated. For this reason, only these portions can be accurately heated to the quenching temperature. That is, only a desired part can be heated to the quenching temperature accurately, and “burn-out” can be prevented.
[0039]
Here, the first conductor portion extends in the longitudinal direction along the end portion of the upper wall of the elongated material in the vicinity of the end portion in the width direction orthogonal to the longitudinal direction, and When the second conductor portion extends in the vicinity of the groove along the groove, and the third conductor portion extends away from the elongated material, the first conductor The portion extends along the longitudinal direction in the vicinity of the end portion in the width direction orthogonal to the longitudinal direction of the upper wall of the long material, and the second conductor portion extends in the vicinity of the groove along the groove. In addition, the “<”-shaped third conductor portion extends away from the long material. Therefore, when an alternating current is passed through the first, second, and third conductor portions, the first conductor portion is located near the end portion in the width direction of the upper wall. Current flows. In addition, since the second conductor portion extends along the groove, a strong eddy current flows also in the vicinity of the groove. On the other hand, since the third conductor portion is disposed away from the long material, an eddy current hardly occurs in the long material due to the alternating current flowing through the third conductor portion. As a result, the eddy current flows in a distributed manner in the vicinity of the end portion in the width direction of the upper wall and in the vicinity of the groove, and these portions are intensively heated. For this reason, only these portions can be accurately heated to the quenching temperature. That is, only a desired part can be heated to the quenching temperature accurately, and “burn-out” can be prevented.
[0040]
In addition, when the induction heating coil includes a fourth conductor portion that is located in the vicinity of the lower wall of the long material and is electrically connected to the second conductor portion, the first and second conductor portions When the long material is cured by quenching after heating the long material, the eddy currents due to the first and second conductor portions are dispersed, so the long material is partially heated and heated. Only the part is cured. For this reason, there exists a possibility that a long material may deform | transform. However, when the lower wall is heated by the fourth conductor portion and rapidly cooled and hardened, the deformation caused by this hardening counteracts with the deformation caused by the portions heated and hardened by the first and second conductor portions. The deformation of the entire long material can be reduced.
[0041]
Further, the long material has grooves extending in the longitudinal direction formed on the left and right side walls of the long material, and the first, second, and third conductor portions face each other. In the case of a pair, the pair of first, second and third conductor portions accurately heat the vicinity of the left and right end portions in the width direction of the upper wall and the vicinity of the two grooves to the quenching temperature. Only the desired part can be heated accurately.
[0042]
Furthermore, when the fourth conductor portion is composed of a pair of conductors respectively disposed in the vicinity of both ends in the width direction orthogonal to the longitudinal direction among the lower walls of the long material, And the deformation caused by the portion heated and cured by the second conductor portion is more reliably canceled by the deformation caused by the portion cured by the fourth conductor portion consisting of a pair of conductors. Is further reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an induction heating coil according to the present invention.
FIG. 2 is a perspective view schematically showing the induction heating coil of FIG.
FIG. 3 shows an induction heating coil arranged facing the side wall of a long material, (a) is a cross-sectional view showing the case of the induction heating coil of the present invention, and (b) is a case of a conventional induction heating coil. FIG.
4A and 4B show a side wall of a long material and positions of induction heating coils, FIG. 4A is a side wall diagram showing an outline of the induction heating coil of the present invention, and FIG. 4B is an outline of a conventional induction heating coil. The eddy current is schematically shown by a two-dot chain line.
5A and 5B schematically show eddy currents generated in a long material, FIG. 5A is a perspective view when the induction heating coil of the present invention is used, and FIG. 5B is a view when a conventional induction heating coil is used. It is a perspective view, and an eddy current is typically shown by a two-dot chain line.
6A and 6B schematically show a quenching pattern of a longitudinal end portion of a long material, FIG. 6A is a schematic diagram showing a quenching pattern when the induction heating coil of the present invention is used, and FIG. It is a schematic diagram which shows a hardening pattern when using the conventional induction heating coil.
7 is a graph showing the hardness distribution in the c, d, e, and f directions in FIG. 6, (a) is a graph when the induction heating coil of the present invention is used, and (b) is a conventional graph. It is a graph when an induction heating coil is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Induction heating coil 20,120 1st conductor part 30,130 2nd conductor part 40,140 3rd conductor part 80,180 4th conductor part 200 Long material 202 Long wall upper wall 202a Both ends 204 of an upper wall Long side wall 206 groove

Claims (1)

A lower wall extending in the longitudinal direction, a pair of side walls each rising with a groove extending from the both ends in the width direction of the lower wall and extending in the longitudinal direction and extending in the longitudinal direction, and facing the lower wall In an induction heating coil having an upper wall extending in the longitudinal direction and induction-heating the side wall of the long material while relatively moving along the longitudinal direction of the long material having a rectangular cross section ,
A first conductor portion extending in the longitudinal direction near a corner of the boundary between the pair of side walls and the upper wall ;
A second conductor portion extending in the longitudinal direction in the vicinity of the groove ;
The one end of the first conductor portion and the one end of the second conductor portion are electrically connected , and are arranged so as to extend in a direction substantially orthogonal to the first and second conductor portions and away from the long material. A " ""shaped third conductor portion;
A fourth conductor portion extending in the longitudinal direction near the corner of the boundary between the pair of side walls and the lower wall ;
The induction heating coil , wherein each of the first, second, third, and fourth conductor portions is a pair facing each other .

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