JP2003213326A - High-frequency heating method and high-frequency heating coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency heating method which reduces manufacturing costs of a high-frequency heating coil, makes replacement of the high-frequency heating coil unnecessary, and improves productivity of circle shape workpieces and to provide the high-frequency heating coil. <P>SOLUTION: The circle shape workpieces W1 to W3 which have different radii from the minimum radius to the maximum radius are heated using a single high-frequency heating coil 20. The high-frequency heating coil 20 consists integrally of a first circular heating conductor part 22, circular heating conductor parts 24a and 24b, lateral side heating conductor parts 26a and 26b installed respectively between the first circular heating conductor part 22 and the circular heating conductor parts 24a and 24b, and a supporting member 30. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating method and a high-frequency heating coil, and more specifically, it heats and quenches the periphery of a plurality of circular workpieces having different radii such as engine valves. In this case, the present invention relates to a high-frequency heating method and a high-frequency heating coil that enable heating with a single high-frequency heating coil.

[0002]

2. Description of the Related Art Conventionally, when heating the periphery of a plurality of circular workpieces having different radii, it is concentric depending on the type of the circular workpieces, that is, the workpieces having different radii. A high frequency heating coil having a heating conductor portion corresponding to the above is used.

An example of this type of high frequency heating coil is the conventional technique disclosed in Japanese Utility Model Laid-Open No. 3-99753.

As shown in FIG. 5, the high-frequency heating coil 1 according to this prior art is concentrically provided with the respective peripheral edges 2a, 3a of circular workpieces 2, 3 having different radii R2, R3. It is provided with arcuate heating conductor portions 4 and 5.

The heating conductors 4 and 5 are integrated in series, and a high frequency power source 7 including a control means via a lead wire 6 is provided.
It is connected to the. Then, the heating conductor portion 4 is positioned at a predetermined position with respect to the peripheral edge 2a of the circular work 2 having a small diameter, or the circular work 3 having the heating conductor portion 5 having a large diameter.
It is positioned at a predetermined position with respect to the peripheral edge 3a, and the peripheral edge 2a or 3a is heated by passing a current from the high frequency power source 7 to the heating conductors 4 and 5.

[0006]

However, in the high-frequency heating coil 1 according to the prior art, the heating conductor portions 4 corresponding to the radii of the circular workpieces 2 and 3 to be heated, that is, the radii R2 and R3, respectively. It is necessary to have 5.

On the other hand, when heating a circular work having a different radius from the circular works 2 and 3, a heating conductor portion having a different radius is additionally provided to the high frequency heating coil 1. Make high frequency heating coil,
Alternatively, another high frequency heating coil must be newly manufactured.

As described above, when various kinds of circular workpieces having different radius dimensions are increasing, the above-mentioned conventional high-frequency heating coil 1 alone cannot cope with all necessary kinds of workpieces. . Therefore, it is necessary to manufacture a number of high-frequency heating coils corresponding to the respective radii of the circular work, and as a result, there is a problem that the manufacturing cost of the high-frequency heating coils increases.

In the process of heating and quenching the circular workpieces 2 and 3, the high-frequency heating coil 1 is replaced with a high-frequency heating coil for that type as the circular workpiece is changed. There is a need and for this reason production must be suspended. In addition, since the work time for this replacement is required, the productivity of the circular work is significantly hindered.

The present invention has been made in view of the above problems, and it is possible to reduce the manufacturing cost of a high-frequency heating coil when heating and processing a plurality of circular workpieces having different radii. Moreover, it is an object of the present invention to provide a high-frequency heating method and a high-frequency heating coil that do not require replacement of the high-frequency heating coil corresponding to the type of circular work and as a result can improve the productivity of the circular work. .

[0011]

A high-frequency heating method according to the present invention is a high-frequency heating method for a plurality of circular workpieces having different radii, which are used to heat a circular workpiece having a minimum radius. A first arc-shaped heating conductor portion formed with a predetermined gap with respect to the peripheral edge of the shaped work, and a predetermined arc with respect to the peripheral edge of the circular shaped work for heating the circular shaped work with the maximum radius. A second arcuate heating conductor portion formed with a gap and the first circular-shaped workpiece having a radius between the circular-shaped workpiece having the minimum radius and the circular-shaped workpiece having the maximum radius to heat the circular workpiece. And a third heating conductor portion formed between the first and second arc-shaped heating conductor portions, wherein the first and second arc-shaped heating conductor portions are spaced apart on the same virtual center line. , The third heating conductor portion is the first and second arcuate heating conductor portions. Positioning the high-frequency heating coil with respect to each circular workpiece using a high-frequency heating coil that is provided along two lines that connect the respective arcs and in which the respective heating conductor portions are integrally formed. And a step of adjusting the voltage or the current and supplying the voltage to the high-frequency heating coil.

Further, the high-frequency heating coil according to the present invention has a first arc-shaped heating conductor portion formed with a predetermined gap with respect to a peripheral edge of a circular-shaped workpiece having a minimum radius, and a circular shape having a maximum radius. A second arc-shaped heating conductor portion formed with a predetermined gap with respect to the periphery of the work, and a third heating conductor portion formed between the first and second arc-shaped heating conductor portions. And the first and second arcuate heating conductor portions are spaced apart from each other on the same virtual center line, and the third heating conductor portion is the first and second arcuate heating conductor portions. Is provided along two lines that connect the respective arcs, and each of the heating conductor portions is integrally formed.

According to the present invention, a circular work having various radii from the minimum radius to the maximum radius is heated by a single high frequency heating coil. Need not be manufactured, and as a result, the manufacturing cost of the high frequency heating coil can be significantly reduced.

Further, since the circular work is heated by using a single high-frequency heating coil, it is not necessary to replace the high-frequency heating coil when changing the type of the circular work, and the circular work can be heated. Since it is only necessary to adjust the position of the high frequency heating coil according to the type of work and the voltage or current output to the high frequency heating coil, the result is
The productivity of circular workpieces can be significantly improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a high frequency heating method and a high frequency heating coil according to the present invention will be given.
The following is a detailed description with reference to the accompanying drawings.

FIG. 1 is a perspective view of a high frequency heating coil 20 according to an embodiment of the present invention.

The high frequency heating coil 20 includes a first arc-shaped heating conductor portion 22, a second arc-shaped heating conductor portion 24, and
A third heating conductor portion 26 provided between the first and second arcuate heating conductor portions 22 and 24 and a support member 30 are integrally configured. Further, the support member 30 has a first
It is composed of a support 30a and a second support 30b. An insulating member 32 is inserted in a gap formed between the first support body 30a and the second support body 30b, and fastening means such as a bolt 34 is provided on the end faces of the support bodies 30a and 30b. Thus, the insulating member 36 is fixed. Note that FIG.
Inside the heating conductor portions 22, 24, 26 and the support member 30, there are provided flow paths (not shown) for circulating a cooling liquid, the first support body 30a and the second support body 30b.
Are provided so as to communicate with the couplers 38a and 38b respectively provided in the.

The first arcuate heating conductor portion 22 has an inner peripheral surface 40 on the inner side in the radial direction.

The second arc-shaped heating conductor portion 24 further includes
It is composed of an arcuate heating conductor portion 24a connected to the first support 30a side and an arcuate heating conductor portion 24b connected to the second support 30b side. The arcuate heating conductor portions 24a and 24b. And are separated by the insulating member 32. In addition, the second arc-shaped heating conductor portion 24,
It has inner peripheral surfaces 42a and 42b on the inner side in the radial direction.

The third heating conductor portion 26 further includes the first arc-shaped heating conductor portion 22 and the arc-shaped heating conductor portion 24.
a side heating conductor portion 26a formed by connecting with a
And a lateral heating conductor portion 26b formed by connecting between the first arc-shaped heating conductor portion 22 and the arc-shaped heating conductor portion 24b.

The side heating conductor portion 26a connects the arc of the inner peripheral surface 40 of the first arc-shaped heating conductor portion 22 and the arc of the inner peripheral surface 42a of the arc-shaped heating conductor portion 24a, Further, it is formed with an inner wall surface 44a including a line curved outward along with these arcs. In addition, this inner wall surface 4
4a is, for example, the arc of the inner peripheral surface 40 and the inner peripheral surface 4
Of course, it may be formed along the common tangent line Q1 with the arc of 2a.

The side heating conductor portion 26b connects the arc of the inner peripheral surface 40 of the first arc-shaped heating conductor portion 22 and the arc of the inner peripheral surface 42b of the arc-shaped heating conductor portion 24b, Further, it is formed with an inner wall surface 44b including a line curved outward along with these arcs. In addition, this inner wall surface 4
4b is a common tangent line Q2 between the arc of the inner peripheral surface 40 and the arc of the inner peripheral surface 42b, as in the case of the inner wall surface 44a.
Of course, it may be formed along the line.

The high frequency heating coil 20 according to the embodiment of the present invention is basically constructed as described above. Next, the high frequency induction heating device 48 to which the high frequency heating coil 20 is applied is described. explain.

FIG. 2 is a partially omitted perspective view of the high frequency induction heating device 48 according to the present embodiment. In FIG. 2, the same components as those of the high-frequency heating coil 20 shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. Further, reference numeral W indicates a work in the high frequency induction heating device 48 according to the present embodiment, and in this case,
It is an engine valve.

The high frequency induction heating device 48 comprises a coil heating section 50, a turntable 52, and a control section 56 including a high frequency power supply 54.

In the coil heating section 50, the high frequency heating coil 20 is fixed to the coil supporting body 62 by tightening the bolt 60 via the insulator 58. Further, the lead wire 64 connected to the control unit 56 is connected to the support member 30 of the high frequency heating coil 20 via the terminal 66 and fixed together with the insulator 58. The upper support member 68 is provided on the upper side of the coil heating unit 50, is supported by another support body (not shown), and is pressed from the valve portion V side of the engine valve W.

In the turntable 52, the lower support member 7
Engine valve W by the clamp 72 provided in 0.
The shaft U side of is supported. Then, the lower support member 7
0 causes the peripheral edge Wa of the engine valve W to rise to move the heating conductor portion 2 of the high-frequency heating coil 20.
Positioned vertically with respect to 2, 24 and 26,
In addition, the rotation is to uniformly heat the peripheral edge Wa over the entire circumference. In the turntable 52, reference numeral 74 indicates a first station to which the engine valve W is supplied, and reference numeral 76.
Indicates a second station where the engine valve W is heated and quenched, and reference numeral 78 indicates a third station where the engine valve W is picked up and transferred to the next processing step.
Indicates a station.

In the control section 56, as the setting conditions for heating the engine valve W, the voltage or current supplied from the high frequency power source 54, the application time of the voltage or current, etc., and the setting conditions for quenching are set. As such, the cooling time and the flow rate of the cooling fluid are set, and the set values are stored and displayed. further,
Positional conditions of the high-frequency heating coil 20 in the sliding direction,
Or the lateral direction (rotational direction) of the turntable 52
Further, the vertical position condition of the lower support member 70 and the like are set, and each position condition is stored and displayed.

In FIG. 2, reference numeral 80 indicates a hose for circulating the cooling liquid from the cooling liquid circulating means (not shown) to the high frequency heating coil 20.

High-frequency induction heating device 4 according to the present embodiment
8 is basically configured as described above,
Next, the operation and effects of this high frequency induction heating device 48 will be described in relation to the high frequency heating method.

The engine valve W until it is supplied to the high frequency induction heating device 48 will be described with reference to FIG.

First, a cut product 82 cut into a predetermined length from a cylindrical raw material is obtained. Next, one end of the cut product 82 is formed by the upset forging method, and an intermediate product 86 including the substantially spherical tip portion 84 is obtained. Subsequently, the tip end portion 84 is formed by the hot forging method, and the valve original product 88 including the valve portion V formed in a substantially umbrella shape is obtained. The engine valve W is obtained through the process of joining the valve original product 88 to the shaft U, and the polishing process and heat treatment of the valve original product 88.

Then, the engine valve W is supplied to the high frequency induction heating device 48 shown in FIG.

First, the control unit 56 reads out the conditions set and stored for each type of the engine valve W. Then, according to the work start command, the high-frequency heating coil 20 along with the coil heating unit 50 slides in the direction of arrow A (that is, the normal direction of the turntable 52) and is positioned at a predetermined position. This predetermined position is, as shown in FIGS. 4A to 4C, peripheral edges W1a to W3 of the engine valve W (corresponding to reference numerals W1 to W3).
It shows the optimum position condition of each of the heating conductor portions 22, 24 and 26 of the high frequency heating coil 20 corresponding to any one of a, and is specified for each type of the engine valve W.

That is, in the case of FIG. 4A, the arc radius R
The first arcuate heating conductor portion 22 having 22 has a radius R1
With respect to the peripheral edge W1a of the engine valve W1 having a,
It is set with a predetermined gap. This engine valve W
1 has a minimum radius to be heated by using the high frequency heating coil 20. In FIG. 4A, reference numeral L is an imaginary line showing a gap with the inner peripheral surface 40.

When the peripheral edge W1a is heated, it is desirable that the gap, that is, the dimensional difference between the arc radius R22 and the radius R1a is set to be larger than 1 mm.
This is to prevent the peripheral edge W1a from being overheated.

In the case of FIG. 4B, the arc diameter R24
The arc-shaped heating conductor portions 24a and 24b having a radius R2a are set with a predetermined gap (shown by an imaginary line L) with respect to the peripheral edge W2a of the engine valve W2 having a radius R2a. The engine valve W2 has a maximum radius to be heated by using the high frequency heating coil 20.

When the peripheral edge W2a is heated, it is desirable that the dimensional difference between the arc radius R24 and the radius R2a is set to be larger than 1 mm, as in the case of the peripheral edge W1a described above.

The center of the arc diameter R22 of the first arc-shaped heating conductor portion 22 and the center of the arc diameter R24 of the arc-shaped heating conductor portions 24a and 24b are arranged apart from each other on the virtual center line P. To be done.

Further, in the case of FIG. 4C, the side heating conductor portions 26a and 26b have a predetermined gap (shown by an imaginary line L) with respect to the peripheral edge W3a of the engine valve W3 having the radius R3a. Is set. In this case, the radius R3a of the engine valve W3 is the radius R1a of the engine valve W1 and the radius R2 of the engine valve W2.
When it is between a, that is, R1a <R3a <R2a
Applied when there is a relationship.

In FIGS. 4A to 4C, the virtual line S
Passes through the center of the engine valves W1 to W3 and coincides with the tangential direction in which the engine valves W1 to W3 are transferred by the turntable 52 or the moving direction in which they are transferred by a conveyor or the like (not shown).

The shaft 72 of the engine valve W supplied to the first station 74 is supported by the clamp 72. Next, the turntable 52 rotates in the direction of arrow B, and the engine valve W is transferred to the second station 76. Subsequently, the lower support member 70 rises in the direction of arrow C and the engine valve W rises to a predetermined position, and at the same time, the upper support member 68 descends in the direction of arrow D and the valve of the engine valve W is lowered. The portion V side is pressed and the engine valve W is vertically positioned on the lower support member 70. The predetermined position is set and stored in the control unit 56 as an optimum position condition for each heating conductor portion 22, 24 and 26 of the high frequency heating coil 20, and is stored for each type of engine valve W. It is specified.

Then, based on the command signal from the control unit 56,
High frequency power supply 54 to lead wire 64 and terminal 66
A predetermined current is supplied (or a predetermined voltage is applied) to the high-frequency heating coil 20 via, and the heating conductor portions 22, 24 and 26 of the high-frequency heating coil 20 cause
The peripheral edge Wa of the engine valve W is heated for a predetermined time. At this time, the engine valve W includes the lower support member 7
Rotating together with 0, the peripheral edge Wa is heated uniformly over the entire circumference. The predetermined current (or the predetermined voltage) and the predetermined time are controlled by the control unit 5.
6, which is set and stored, and is specified for each type of engine valve W.

After heating for the predetermined time, the supply of the predetermined current is stopped. Then, the cooling fluid is injected toward the peripheral edge Wa of the engine valve W from a cooling fluid injection means (not shown) such as a cooling nozzle for a predetermined cooling time. As a result, the peripheral edge Wa is rapidly cooled and quenched. It should be noted that this predetermined cooling time depends on the control unit 56.
Is set and stored in, and is specified for each type of engine valve W.

Then, the above-mentioned upper support member 68 rises and the engine valve W descends together with the lower support member 70, retreats to their original positions, and the turntable 52 rotates in the direction of arrow B again. Then, the engine valve W transferred to the third station 78 is released from the support by the clamp 72, and transferred to the next step by a transfer means (not shown) such as a loader.

Here, the setting conditions set in the control unit 56 of the high-frequency induction heating device 48 according to this embodiment will be described.

Considering the production takt time of the engine valve W, the setting condition relating to time, that is, the high frequency power source 5
Various experiments were conducted with the application time of the voltage or current supplied from No. 4 and the cooling time for the quenching treatment kept constant.

The application time is 2.5 seconds, the cooling time is 1.5 seconds, the voltage is 200V in the engine valve W1 in FIG. 4A, and the voltage is 160V in the engine valve W2 in FIG. 4B. In addition, in the engine valve W3 in FIG. 4C, when the voltage is 180 V, the engine valve W1,
Good results were obtained for the surface hardness and the quenching depth of the peripheral edges W1a, W2a and W3a of W2 and W3. Moreover, the surface hardness and the quenching depth of the peripheral edges W1a, W2a, and W3a are almost the same.

From the above, by changing the setting of the voltage (or current) as described above, as long as it has a radius between the engine valves W1 and W2, other than the engine valve W3. Types are also available.

The high-frequency induction heating apparatus 48 according to the present embodiment employs a system in which the high-frequency heating coil 20 slides in one direction together with the coil heating unit 50. When various irregularities are dealt with, such as the part to be specified is partially specified, for example, the coil heating unit 5 is placed on the XY table.
Of course, 0 may be placed and moved in two directions.

As described above, according to the high frequency induction heating device 48 to which the high frequency heating coil 20 according to the embodiment of the present invention is applied, the engine valve having different radii from the minimum radius to the maximum radius. W1-W3
Since the heating is performed by the single high-frequency heating coil 20, it is not necessary to manufacture a number of high-frequency heating coils 1 as in the prior art, and as a result, the high-frequency heating coil 2 is produced.
The production cost of 0 can be greatly reduced.

Further, since the heating is performed by the single high-frequency heating coil 20, it is not necessary to replace the high-frequency heating coil 20 when changing the type of the engine valve W. Since it is only necessary to adjust the position of the high-frequency heating coil 20 set to and the voltage (or current) output to the high-frequency heating coil 20, it is possible to significantly improve the productivity of the engine valve W as a result. it can.

[0053]

According to the present invention, the following effects can be obtained.

That is, since a circular work having various radii from the minimum radius to the maximum radius is heated by a single high frequency heating coil, it is necessary to manufacture many high frequency heating coils as in the prior art. As a result, the manufacturing cost of the high frequency heating coil can be significantly reduced.

Further, since the circular work is heated by using a single high-frequency heating coil, it is not necessary to replace the high-frequency heating coil when changing the type of the circular work, and the circular work can be heated. Since it is only necessary to adjust the position of the high frequency heating coil according to the type of work and the voltage or current output to the high frequency heating coil, the result is
The productivity of circular workpieces can be significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a high-frequency heating coil according to an embodiment of the present invention.

FIG. 2 is a partially omitted perspective explanatory view of a high frequency induction heating device to which a high frequency heating coil according to an embodiment of the present invention is applied.

FIG. 3 is an explanatory diagram of an engine valve according to the present embodiment.

FIG. 4A is an explanatory plan view showing the positional relationship between the high-frequency heating coil according to the present embodiment and the engine valve having the minimum radius. FIG. 4B is an explanatory plan view showing the positional relationship between the high-frequency heating coil according to the present embodiment and the engine valve having the maximum radius. FIG. 4C is a plan explanatory view showing a positional relationship between the high-frequency heating coil according to the present embodiment and an engine valve having a radius between the minimum radius and the maximum radius.

FIG. 5 is an explanatory plan view showing a positional relationship between a high-frequency heating coil and a circular work according to a conventional technique.

[Explanation of symbols]

20 ... High-frequency heating coil 22 ... First arc-shaped heating conductor portion 24 ... Second arc-shaped heating conductor portion 24a, 24b
... Arc-shaped heating conductor portion 26 ... Third heating conductor portion 26a, 26b
... Side heating conductor portion 30 ... Support member L, S ... Virtual line P ... Virtual center line Q1, Q2 ... Common tangent line R22, R24 ... Arc diameter R1a, R2
a, R3a ... Radius W, W1, W2, W3 ... Engine valve (workpiece) Wa, W1a, W2a, W3a ...

Claims (2)

[Claims] 1. A high-frequency heating method for a plurality of circular workpieces having different radii, wherein a predetermined gap is provided around the periphery of the circular workpieces for heating the circular workpiece having the minimum radius. First formed
A second arc-shaped heating conductor part and a second part formed to have a predetermined gap with respect to the peripheral edge of the circular work for heating the circular work having the maximum radius.
Arc heating conductor part, and the first and second arc heating conductor parts for heating a circular work having a radius between the minimum radius circular work and the maximum radius circular work. And a third heating conductor portion formed between the first heating conductor portion and the second heating conductor portion, wherein the first and second arc-shaped heating conductor portions are spaced apart on the same virtual center line. Each of the circular shapes is formed by using a high-frequency heating coil which is provided along two lines connecting the respective arcs of the first and second arc-shaped heating conductor parts and in which the respective heating conductor parts are integrally formed. A high-frequency heating method, comprising: positioning the high-frequency heating coil with respect to a work; and adjusting the voltage or current and supplying the adjusted high-frequency heating coil to the high-frequency heating coil. 2. A first arc-shaped heating conductor portion formed with a predetermined gap with respect to a peripheral edge of a circular work having a minimum radius, and a predetermined gap with respect to a peripheral edge of a circular work having a maximum radius. A second arc-shaped heating conductor portion formed with the third arc-shaped heating conductor portion, and a third heating conductor portion formed between the first and second arc-shaped heating conductor portions. And a second arc-shaped heating conductor part are spaced apart from each other on the same virtual center line, and the third heating conductor part connects two arcs of the first and second arc-shaped heating conductor parts. A high-frequency heating coil provided along a line, wherein each of the heating conductor portions is integrally formed.