JP3810621B2 - Induction heating coil and heat treatment method for shaft member having multi-shaped heat treatment part - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating coil and a heat treatment method for heat-treating a shaft member having a multi-shaped heat treatment portion such as a cam shaft provided with a plurality of cams that are coaxially surface-treated. The present invention is applied to heat treatment of a camshaft having a journal portion that requires surface heat treatment up to an adjacent portion.
[0002]
[Prior art]
For example, when heat-treating a cam shaft provided with a plurality of cams 3 and 4 on one shaft as shown in FIG. The two induction coils 6 and 7 are separated from each other. First, the cam portions 3 and 4 are heated by the coil 7 and heat treated, and then the journal portion 2 is heated by the coil 6 and heat treated. The method of heat treatment was adopted. Although the coils 6 and 7 are shown at the same time in FIG. 4, the coils 6 and 7 are actually used separately.
[0003]
This is because when the coil 6 and the coil 7 are simultaneously used to heat the journal portion 2 and the cam 3 at the same time, the corner portion 3a of the short diameter portion of the cam 3 adjacent to the journal portion 2 is overheated, and this portion is quenched. This is because when the layer becomes deep and temper cracking occurs, or when it is severe, it melts, and simultaneous quenching is impossible. In order to perform quenching at a time while avoiding this, the lower surface of the coil 6 may be separated from the cam 3, but the journal portion 2 is required to have a hardened layer up to the portion 2 a close to the cam 3. I can't. Therefore, as described above, heat treatment was required in two stages.
[0004]
[Problems to be solved by the invention]
However, if the heat treatment is performed in two stages as described above, it is necessary to switch between the coils 6 and 7 when processing with one apparatus, which increases the number of coils and the number of coils, which takes time and effort for mounting. There is a problem. Or it is necessary to use two heat processing apparatuses.
[0005]
Accordingly, an object of the present invention is to solve the above-described problems and provide a heating coil and a heat treatment method for a shaft member having a multi-shaped heat treatment portion that can be heat-treated without switching coils with a single heat treatment apparatus.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the induction heating coil for a shaft member having a multi-shaped heat treatment part according to the present invention heats a shaft member provided with two or more heat treatment parts having different outer diameters or shapes in the axial direction. When two or more cylindrical coils corresponding to the outer diameter or shape of each heat treatment part are connected in series so that current flows in the same direction, and one heat treatment part is heated by any one of the cylindrical coils An integral induction heating coil is formed by arranging the other coils in the axial direction at intervals such that the other coils are removed from the corresponding parts to be processed.
[0007]
The heat treatment method of the shaft member having a heat treatment region of a multi-shape of the present invention, two or more outer diameter or the axial direction in the heating of the shaft members having different thermal processing shapes is provided, outside each thermal processing unit Two or more cylindrical coils corresponding to the diameter or shape are connected in series so that current flows in the same direction, and each of the other coils corresponds when one of the cylindrical coils heats one heat treatment part. Using an integral induction heating coil arranged in the axial direction at an interval so as to be disengaged from the part to be processed, the one coil heats and heat-treats one heat treatment part, and then moves in the axial direction to the other coil. The other heat treatment portions are sequentially heated to perform heat treatment.
[0008]
For example, in the heating of a shaft member provided with heat treatment parts having different outer diameters and shapes in the axial direction, such as the cam part and journal part of the cam shaft, a large diameter coil corresponding to the heat treatment part The small diameter coil is connected in series to form an integral coil, and the large diameter coil is heated to heat the large diameter heat-treated portion, and then the small diameter coil is heated to heat treat the small diameter heat treated portion. At this time, the interval between the two coils is provided such that, for example, when the large-diameter portion is heated, the small-diameter coil is detached from the shaft member, the small-diameter coil does not heat the shaft member. If it does in this way, two or more heat processing parts from which a shape differs can be heated and heat-treated, without giving a hindrance to other heat processing parts by one heat processing apparatus, without changing a coil.
[0009]
In the heat treatment method for a shaft member having a polymorphic heat treatment portion according to the present invention, one or more cam portions subjected to surface heat treatment and a journal portion subjected to surface heat treatment provided adjacent to any one of the cam portions are coaxial. This is effective for heat treatment of the camshaft.
[0010]
It is desirable that both ends of the shaft member are supported by a non-magnetic metal or non-magnetic non-metal support and heated. In this way, when one coil heats the part to be heat-treated, the support is not induction-heated even if the other coil is out of the shaft to be processed and is in the position of the support. The shaft body is reliably supported and heat treatment can be performed smoothly.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to an illustrated embodiment. FIG. 1 is a diagram for explaining the relationship between a cam shaft and an induction heating coil in quenching of the cam shaft according to the embodiment of the present invention, FIG. 2 is a perspective view of the induction heating coil of the embodiment of the present invention, and FIG. It is a figure which shows the shape of the cam shaft which is heat processing material.
[0012]
The shape of the cam shaft, which is a heat-treated member, will be described with reference to FIG. 3. The cam shaft (shaft member) 1 is composed of a shaft portion 5 with a journal portion 2 and a cam 3 adjacent thereto, and a cam 3 at a slight interval. Is formed with a cam 4 that is eccentric with respect to the surface, and the surfaces of the journal portion 2 and the cams 3 and 4 are heated and heat-treated.
[0013]
Referring to FIGS. 1 and 2, the induction heating coil 10 includes a small diameter coil 11 that heats the journal portion 2 (small diameter portion) and a large diameter coil 12 that heats the cams 3 and 4 (large diameter portion) in the axial direction. They are arranged at intervals and connected in series by a lead material 15 to be integrally formed.
[0014]
The small-diameter coil 11 is a cylindrical coil having an inner diameter that forms a predetermined gap with the outer periphery of the journal portion 2. The large-diameter coil 12 has a ring-shaped convex portion 13a at a position corresponding to the cam 3 and a ring-shaped convex shape at a position corresponding to the cam 4 on the inner periphery of a cylindrical coil having a width straddling the two cams 3 and 4. A portion 13b is provided. The inner diameters of the ring-shaped convex portions 13a and 13b are such that a predetermined gap is formed between the maximum outer diameters of the cams 3 and 4, respectively. Thus, the coil which heats two cams simultaneously is what the inventors previously proposed in Japanese Patent Application No. 2000-176356.
[0015]
As shown in FIGS. 1 and 2, the small-diameter coil 11 and the large-diameter coil 12 are coaxially spaced apart, one end 11a of the small-diameter coil 11 is one end 14a of the lead plate 14, and the other end 11b is the lead plate 15. Is connected to one end 15a. One end 12 a of the large-diameter coil 12 is connected to the other end 15 b of the lead plate 15, and the other end 12 b is connected to one end 16 a of the lead plate 16. As a result, when a high frequency current is loaded on the other ends 14 b and 16 b of the lead plates 14 and 16, the current flows through the small diameter coil 11 and the large diameter coil 12 in the same circumferential direction.
[0016]
The small-diameter coil 11 and the large-diameter coil 12 are arranged at intervals in the axial direction so that one coil heats the journal portion or the cam portion and the other coil is detached from the cam shaft 1. That is, the length of the lead plate 15 is set to be like this. Thereby, when one coil is heating any one of the heat treatment parts, the other coil does not heat the camshaft 1 even if a current flows through both coils.
[0017]
Both ends of the cam shaft 1 are supported by an upper center 21 and a lower center 22, and are rotated by a driving means (not shown) by the lower center 22. The upper center 21 and the lower center 22 support the cam shaft 1. The journal portion 2 or the cam portions 3 and 4 are moved to the positions of the small diameter coil 11 and the large diameter coil 12 respectively by moving up and down in the figure. The upper center 21 and the lower center 22 are made of stainless steel center portions 21a and 22a and insulator center shaft portions 21b and 22b, respectively. As shown in the lower center 22 of FIG. 1, the middle 22b may be an insulator, and both ends 22a and 22c may be stainless steel. In this way, even if the large-diameter coil 12 is at the position of the lower center 22 as shown in FIG. 1, the lower center 22 is not heated. The same applies to the upper center. As a result, the camshaft is reliably supported and the power consumption can be reduced.
[0018]
Hereinafter, the operation of quenching and heat-treating the camshaft using the induction heating coil having the above configuration will be described. First, the cam shaft 1 is supported by the upper center 21 and the lower center 22, and the cams 3 and 4 are set so as to be in the lower position covered with the large-diameter coil 12 as indicated by a chain line in FIG. At this position, the cam shaft 1 is rotated through the lower center 22 by a driving means (not shown), a high frequency current is applied to the lead plates 14 and 16 to heat the cams 3 and 4 to the quenching temperature, and a cooling means (not shown). To quench and quench. At this time, since the small-diameter coil 11 is separated from the cam shaft 1 and is at the position of the upper center 21, the cam shaft 1 is not heated, and since the upper center 21 is an insulator, it is heated even in the small-diameter coil 11. It will never be done.
[0019]
Next, the cam shaft 1 is moved upward in FIG. 1 so that the journal portion 2 is positioned at the small diameter coil 11. At this position, similarly to the quenching of the cam portion, the camshaft 1 is rotated, a high frequency current is applied to the lead plates 14 and 16, the outer periphery of the journal portion 2 is heated, quenched and quenched. At this time, similarly to the quenching of the cam portion, the large-diameter coil 12 is separated from the cam shaft 1 and is at the position of the lower center 22, and the lower center 22 is also an insulator like the upper center 21. Even if it exists in 12, it is not heated. Thereby, the heat treatment of the camshaft 1 is completed.
[0020]
Thus, according to the induction heating coil of the present invention, it is not necessary to remove and switch the coil with one apparatus, and the journal part and the cam part can be heat-treated. In addition, since the coil with the optimum shape can be selected for heating the journal and cam parts, the above-mentioned disadvantages such as overheating of the corners of the cam do not occur, and an appropriate hardened layer is formed on the journal and cam parts. Can be made.
[0021]
In this embodiment, two large-diameter coils and one small-diameter coil are used for heat-hardening at two locations, but the number of coils can be increased to heat-harden at three or more locations. It can also be applied to tempering.
[0022]
【The invention's effect】
As described above, according to the induction heating coil and the heat treatment method of the present invention, the shaft member having a multi-shaped heat treatment portion such as a cam shaft provided with heat treatment portions having two or more different shapes in the axial direction. In this heat treatment, multiple multi-shaped parts can be heat treated with a single heat treatment device without removing the heating coil and switching, so heat treatment with an appropriate hardened layer can be performed efficiently and the quality of the quenched cam shaft etc. Improvement and cost reduction can be achieved.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a relationship between a cam shaft and an induction heating coil in quenching of a cam shaft according to an embodiment of the present invention.
FIG. 2 is a perspective view of an induction heating coil according to an embodiment of the present invention.
FIG. 3 is a view showing the shape of a camshaft in a heat-treated material according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a conventional camshaft heating method.
[Explanation of symbols]
1 cam shaft (shaft member), 2 journal section, 3 cam, 4 cam, 5 shaft body, 6 small diameter coil, 7 large diameter coil, 10 induction heating coil, 11 small diameter coil, 12 large diameter coil, 13a, 13b ring shape Convex part, 14, 15, 16 Lead plate, 21 Upper center, 22 Lower center

Claims (4)

In heating a shaft member provided with two or more heat treatment parts having different outer diameters or shapes in the axial direction, current flows in two or more cylindrical coils corresponding to the outer diameters or shapes of the heat treatment parts in the same direction. When one heat treatment part is heated in series with any one of the cylindrical coils, the other induction coils are arranged in the axial direction so as to be separated from the corresponding part to be treated. An induction heating coil for a shaft member having a multi-shaped heat treatment site, wherein a coil is formed. In heating a shaft member provided with two or more heat treatment parts having different outer diameters or shapes in the axial direction, current flows in two or more cylindrical coils corresponding to the outer diameters or shapes of the heat treatment parts in the same direction. Are connected in series as described above , and when one heat treatment part is heated by any one of the cylindrical coils, integral induction heating is arranged in an axial direction at intervals such that other coils are removed from the corresponding parts to be treated. using a coil, after one of the heat treatment unit is heated to a heat treatment at said one coil, multi-shaped, characterized in that by moving in the axial direction to heat treatment by other thermal processing unit successively heated by the other coil The heat processing method of the shaft member which has these heat processing parts.   The shaft member is a cam shaft having coaxially one or more cam portions subjected to surface heat treatment and a journal portion subjected to surface heat treatment provided adjacent to any one of the cam portions. Item 3. A heat treatment method for a shaft member having the multi-shaped heat treatment part according to Item 2.   4. The method for heat-treating a shaft member having a multi-shaped heat treatment part according to claim 2, wherein both ends of the shaft member are supported by a non-magnetic metal or a non-magnetic non-metal support and heated. .

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