JPH02267215A - High frequency heating coil and surface quenching apparatus using the coil - Google Patents

Abstract

PURPOSE:To obtain a high frequency heating coil surely forming hardened layer even at steps in the boundary between columnar parts in a work by arranging the work of a shaft material having small diameter and multistages between a first and a second heating parts and constituting the coil so as to heat the work while rotating, centering the work axis. CONSTITUTION:The high frequency current supplied to the arrow mark direction from a high frequency source 60 is branched into B current and C current in the upper part coil 10. Successively, these equal currents are joined at a connecting part of a first conductor 30, upper horizontal part 32 and the coil 10, and after passing through the first heating part 31 and a lower horizontal part 33 as D current, this is branched into E current and F current at a connecting part of a horizontal part 33 and the lower coil 20 and passed through the coil 20. Then, these currents are joined at a connecting part of the coil 20 and lower horizontal part 42 of a second conductive body 40, and after passing through the horizontal part 42, the second heating part 41 and an upper horizontal part 43 in oder as G current, this is returned back to the electric source 60 as H current. Then, after completing heating of the work 1, cooling liquid for quenching is supplied into a cooling jacket 50 to the arrow mark direction and discharged 54 and the surface of the work 1 is uniformly cooled to form good hardening layer 4a on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a high-frequency heating coil and a surface hardening device for small-diameter multi-stage shafts, etc., using the high-frequency heating coil.

<Prior Art> Hereinafter, a conventional high-frequency heating coil used in a surface hardening device for small-diameter multistage shaft objects will be described with reference to the drawings.

FIG. 4 is a drawing for explaining a conventional high-frequency heating coil for hardening small-diameter multistage shaft objects, and FIG. 4(a)
is a perspective view of the end of an example of a small-diameter multi-stage shaft, FIG. 4 (B) is a perspective view of a multi-turn coil, and FIG. 4 (C) is a multi-turn coil and a small-diameter multi-stage shaft inserted into this coil. FIG. 4(d) is a cross-sectional view of the multi-turn
This shows a hardened layer formed on the side surface of the end of a small-diameter multi-stage shaft by heating with a coil.

In FIG. 4(a), two steps are provided at the end of the small-diameter multistage shaft 1 whose longitudinal direction is in the direction of arrow A, and three cylindrical portions 1a, lb, and lc having different diameters are formed. There is. This small-diameter multistage shaft object 1 is used for a camshaft, and the central axis of the cylindrical portion 1b is offset from the central axes of the cylindrical portions 1a and 1c.

Conventionally, in order to induction harden the side surface of the end of such a small-diameter multi-stage shaft 1, as shown in FIG. , 2b, 2c connected in series has been used. As shown in FIG. 4(C), this multi-turn coil 2 is fitted onto the small-diameter multi-stage shaft 1, and the multi-turn coil 2 is rotated around the longitudinal axis 1d. As shown in Figure 4), a current is supplied from the high frequency power source 3 to both ends of the coil 20 to heat the surface of the small diameter multi-stage shaft 1, and then the cooling liquid is jetted out from the cooling liquid jacket (not shown) to generate the small diameter multi-stage shaft. The shaft 1 is cooled to form a hardened layer 4 as shown in FIG. 1(d).

<Problem to be solved by the invention> However, with the above-mentioned conventional surface hardening device,
When surface hardening is performed on the side surface of the end of the small-diameter multi-stage shaft, as shown in FIG. 1b and l
There is a problem in that the hardened layer 4 is not formed at the stepped portion 5b at the boundary with c. That is, when the multi-turn coil 2 shown in FIG. Since the coils are separated into coils 2a, 2b, and 2c, a sufficient current is induced by the multi-turn coil 2 in the step portions 5a and 5b corresponding to the portions between these coils 2a, 2b, and 2c, and the coils are heated. Never.

Therefore, no hardened layer is formed on the step portions 5a and 5b.

The present invention was devised in view of the above circumstances, and when induction hardening is applied to the side surface of the end of a small-diameter multi-stage shaft, etc., the present invention can also be applied to the stepped portion of the boundary between the cylindrical portions formed at the end. It is an object of the present invention to provide a high-frequency heating coil that can always form a hardened layer of a predetermined thickness, and a surface hardening device for small-diameter multistage shafts and the like using this high-frequency heating coil.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the high-frequency heating coil of the present invention uses high-frequency heating to heat the side surface of a substantially columnar workpiece while rotating it around an axis in the longitudinal direction of the workpiece. A substantially annular upper coil whose one end is connected to a high-frequency power supply, a substantially annular lower coil disposed opposite to the upper coil, and a first heating portion having a shape substantially corresponding to the side surface of the workpiece. a first conductor that connects the upper coil and the lower coil, and a second heating section that has a shape that roughly corresponds to the side surface of the workpiece and has one end connected to the lower coil and the other end connected to the other end of the high-frequency power source. 2 conductors, and the first heating section and the second heating section are arranged on both sides of the workpiece so as to be substantially opposed to each other.

Further, the surface hardening apparatus for small-diameter multi-stage shaft objects, etc. of the present invention includes the high-frequency heating coil and a pair of cooling jackets arranged to face each other with the first conductor and the second conductor interposed therebetween, and The cooling jacket is hollow and insulating, and has quenching coolant injection holes provided on the surface facing the first and second conductors.

Effect> A small-diameter multi-stage shaft or the like, which is a workpiece, is installed between the first heating part of the first conductor and the second heating part of the second conductor of the high-frequency heating coil. The workpiece is rotated about the centerline of its longitudinal axis.

A high frequency heating coil cooling liquid is supplied to the high frequency heating coil, passes through the upper coil, the first conductor, the lower coil, and the second conductor while cooling, and is then discharged.

The high frequency current supplied to the upper coil from the high frequency power supply is
After splitting the flow through the upper coil, the flow merges and passes through the first heating section of the first conductor, enters the lower coil and is divided, and then merges and passes through the second heating section of the second conductor before returning to the high frequency power source.

The magnetic fluxes generated in the workpiece by the current shunted to the upper coil cancel each other out, and similarly, the magnetic fluxes generated in the workpiece by the current shunted to the lower coil also cancel each other out. Therefore,
The surface of the workpiece is uniformly heated by the current induced in the axial direction of the workpiece by the current flowing through the first heating section and the second heating section.

When the heating of the workpiece is completed, the cooling liquid is sprayed onto the surface of the workpiece from the quenching cooling liquid injection hole of the cooling jacket to cool the workpiece and form a good hardened layer on the surface of the workpiece.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings. 1 to 3 show an embodiment of the present invention, and FIG. 1(a)
is a partially cutaway perspective view of the high-frequency heating coil, Figure 1 (b
) is a perspective view of a cooling device that constitutes a surface hardening device in combination with a high-frequency heating coil, FIG. 2 is a perspective view of the surface hardening device, and FIG. 3 is an axial cross-sectional view of the end of a small-diameter multi-stage shaft. It is.

As shown in FIG. 1(a), the high-frequency heating coil 100 of this embodiment includes an upper coil 1O1, a lower coil 20, a first conductor 30, and a second conductor made of a hollow rectangular prism made of a highly conductive metal. It is equipped with 40.

The upper coil 10 has a substantially annular shape, and one end of a high frequency power source 60 is connected to a power supply connection part 11 provided on the upper coil 10. A lower coil 20 having a substantially annular shape and substantially the same shape as the upper coil 10 is disposed opposite the upper coil 10.

A first conductor 3 connecting the upper coil 10 and the lower coil 20
0 has a first heating section 31 having a shape corresponding to the side surface 1e of the workpiece shown in FIG. 3, and an upper horizontal section 32 and a lower horizontal section 33 that are linear, respectively.

One end of the upper horizontal part 32 is connected to the upper end of the first heating part 31 (upper in FIG. 1(a)), and the other end is connected to the inner periphery of the upper coil lO at a position opposite to the power supply connection part 1. It is connected to the. One end of the lower horizontal part 33 is connected to the lower end of the first heating part 31, and the other end is connected to the lower coil 20. The upper horizontal part 32 and the lower horizontal part 33 are arranged to face each other. The first heating section 31 is arranged inside the space formed by the upper coil 10 and the lower coil 20.

The second conductor 40 connecting the lower coil 20 and the other end of the high-frequency power source 60 is a second heating section 41 formed in a shape corresponding to the side surface 1e of the workpiece shown in FIG. 3, similarly to the first heating section 31. and a linear lower horizontal part 42 and an upper horizontal part 43, respectively.
and a power supply connection part 44.

One end of the lower horizontal part 42 is connected to the lower end of the second heating part 41, and the other end is connected to the lower coil 20 at a position opposite to the part where the lower horizontal part 33 of the first conductor 30 is connected to the lower coil 20. It is connected. One end of the upper horizontal part 43 is connected to the second
It is connected to the upper end of the heating section 41, and the other end is connected to the power supply connection section 44. Lower horizontal part 42 and upper horizontal part 4
It is arranged to face 3. Second heating section 41
is arranged opposite to the first heating section 31 of the first conductor 30 and inside the space formed by the upper coil 10 and the lower coil 20.

Furthermore, the first heating section 31 of the first conductor 30 and the second heating section 41 of the second conductor 40 seem to be approximately symmetrical with respect to the straight line connecting the center point of the upper coil IO and the center point of the lower coil 20. It is formed and arranged in

Note that the flat plate 46 attached to the inner periphery of the lower coil 20
is provided with screw holes 47 for fixing the cooling jacket to the high-frequency heating coil 100 when the cooling jacket described later is combined with the high-frequency heating coil 100.

The surface hardening apparatus of this embodiment includes the high frequency heating coil 10.
0 and a cooling device 200.

As shown in FIG. 1b), the quenching cooling device 200 includes a pair of cooling jackets 50. As shown in FIG. cooling jacket 50
is a hollow insulating material having a substantially semicylindrical shape, and has a hollow protrusion 51 formed at its upper part, and a quenching coolant supply port 5 to which a quenching coolant supply pipe (not shown) is connected to the protrusion 51.
2 is formed. A substantially arc-shaped groove 53 is formed on the surface of the cooling jacket 50 opposite to the semicylindrical peak, and a plurality of quenching coolant injection holes 54 are formed in this groove 53.
is provided.

To assemble the surface hardening apparatus of this embodiment, the pair of cooling jackets 50 are positioned above the high-frequency heating coil 100 and then lowered so that the pair of cooling jackets 50 are placed above the first conductor 30 and the second conductor 40 on both sides. , into the space formed by both lower coils, and screws (not shown) are inserted into the screw holes 47 to fix the cooling jacket 50 to the high-frequency heating coil 100. FIG. 2 is a perspective view of the surface hardening apparatus assembled in this manner.

Note that 55 is a core inserted between the upper horizontal part 32 and the lower horizontal part 33 of the first conductor 30 and between the upper horizontal part 43 and the lower horizontal part 42 of the second conductor 40. The presence of the core 55 can increase the magnetic density generated in the heated portion of the workpiece.

Next, the operation of the high frequency heating coil and surface hardening device of this embodiment will be explained.

First, between the first heating part 31 of the first conductor 30 of the high-frequency heating coil 100 and the second heating part 41 of the second conductor 40, as shown in FIG. 1 is installed. This workpiece is similar to the small-diameter multistage shaft explained in FIG. 4(a), and the cross section of the end thereof has a shape as shown in FIG. 3. 1d is an axis in the longitudinal direction of the small-diameter multi-stage shaft object l, and the small-diameter multi-stage shaft object l is rotated around the axis 1d. And the first heating section 31
and the second heating section 41 are arranged symmetrically with respect to the axis 1d. In addition, if the cross-sectional shape of the small-diameter multi-stage shaft object 1 on a plane passing through the axis 1d is not completely symmetrical with respect to the axis 1d, the maximum radius in the direction perpendicular to the axis 1d at each step at the end of the small-diameter multi-stage shaft object 1 The first heating section 31 and the second heating section 41 are arranged so that there is a gap between the side surface of the position and the first heating section 31 and between this side surface and the second heating section 41 .

The power supply connections 11 and 44 of the high frequency heating coil 100 include
A high-frequency heating coil cooling liquid supply pipe and a discharge pipe (not shown) are connected to each other, and the high-frequency heating coil cooling liquid is supplied as indicated by arrow P.
It enters the high-frequency heating coil 100 as shown in , passes through the upper coil 10 , the first conductor 30 , the lower coil 20 , and the second conductor 40 while being cooled, and is then discharged as shown by the arrow Q.

As shown in FIG. 1(a), the high frequency current in the direction of the arrow supplied from the high frequency power supply 60 (hereinafter referred to as A current, hereinafter also referred to in the same manner as the current in the other arrow directions) is connected to the power source. 11, the current is shunted to the upper coil 10, and the B current and C current are
After separating from the current, it joins at the connection part between the upper horizontal part 32 of the first conductor 30 and the upper coil 10, and sequentially passes through the upper horizontal part 32, the first heating part 31, and the lower horizontal part 33 of the first conductor 30. After passing as a power source, the lower horizontal part 33 and the lower coil 20
The current is divided into E current and F current at the connection part of lower coil 20.
pass through. Then, the lower coil 20 and the lower horizontal part 42 of the second conductor 40 meet at the connection part, and after successively passing through the lower horizontal part 42, the second heating part 41, and the upper horizontal part 43 of the second conductor 40 as a C current. , returns to the high frequency power supply 60 from the power supply connection part 44 as an H current.

The magnetic fluxes generated in the workpiece by the B current and the C current cancel each other out. Similarly, the magnetic fluxes generated in the workpiece by the E current and the F current also cancel each other out, so the currents that contribute to heating the workpiece are the D current and the C current. Due to the D current and C current, a current flows in the axial direction of the workpiece on the surface of the workpiece, and since the workpiece is being rotated around the center line of the workpiece axis, the surface of the workpiece is uniformly heated. Ru.

When the heating of the workpiece is completed, the quenching coolant supplied to the quenching coolant supply port 52 of the cooling jacket 5° in the direction of arrow S is discharged from the quenching coolant injection hole 54 and sprays onto the surface of the workpiece. Cool evenly. Then, a good hardened layer 4a as shown in FIG. 3 is obtained on the side surface of the end portion of the workpiece.

<Effects of the Invention> As explained above, the high-frequency heating coil of the present invention is a high-frequency heating coil that heats the side surface of a substantially columnar workpiece while rotating the workpiece around the longitudinal axis of the workpiece. The upper coil has an approximately annular upper coil connected to a high frequency power supply, an approximately annular lower coil disposed opposite to the upper coil, and a first heating section having a shape approximately corresponding to the side surface of the workpiece. It includes a first conductor that connects the lower coil, and a second conductor that has a second heating part shaped approximately corresponding to the side surface of the workpiece and has one end connected to the lower coil and the other end connected to the other end of the high-frequency power source. , the first heating section and the second heating section are arranged on both sides of the workpiece so as to be substantially opposed to each other.

The workpiece, which is a small-diameter multi-stage shaft object, is heated by a high-frequency heating coil that is placed between the first heating section and the second heating section and is rotated about the center line of the shaft of the workpiece.

Further, the surface hardening device of the present invention includes the high-frequency heating coil and a pair of cooling jackets arranged to face each other with a first conductor and a second conductor interposed therebetween, and the cooling jacket is a hollow insulating member. Quenching coolant injection holes are provided on the surface facing the first and second conductors.

Therefore, when the surface of the end of a small-diameter multistage shaft is hardened using the surface hardening apparatus of the present invention, the current flows uniformly across the surface of the workpiece, and the hardening cooling liquid is directly applied to the surface to be hardened. By being able to spray an appropriate amount and obtain a sufficient cooling effect,
A good cured layer can be obtained.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, and FIG.
) is a partially cutaway perspective view of the high-frequency heating coil, Figure 10
)) is a perspective view of a cooling device that constitutes a surface hardening device in combination with a high-frequency heating coil, FIG. 2 is a perspective view of the surface hardening device, and FIG. 3 is an axial cross-section of the end of a small-diameter multi-stage shaft. It is a diagram. FIG. 4 is a drawing for explaining a conventional high-frequency heating coil for hardening small-diameter multistage shaft objects.
) is a perspective view of the end of a small-diameter multi-stage shaft, Figure 4 (Q)) is a perspective view of a multi-turn coil, and Figure 4 (C) is a perspective view of a multi-turn coil.
It is a cross-sectional view of a turn coil and a small-diameter multi-stage shaft inserted into this coil, and FIG. 4 (ci) shows a hardened layer formed on the side surface of the end of the small-diameter multi-stage shaft by heating with the multi-turn coil. . 10... Upper coil, 20... Lower coil, 3°・
...first conductor, 31...first heating section, 4o...second
Conductor, 41... Second heating section, 5o... Cooling jacket, 54... Quenching coolant injection hole, 6o... High frequency power source. Patent applicant Fuji Electronics Industry Co., Ltd.

Claims (2)

[Claims] (1) In a high-frequency heating coil that heats the side surface of a nearly columnar workpiece while rotating it around the longitudinal axis of the workpiece, this high-frequency heating coil consists of a roughly annular upper coil with one end connected to a high-frequency power supply. a substantially annular lower coil disposed opposite to the upper coil; a first conductor having a first heating portion shaped approximately corresponding to the side surface of the workpiece and connecting the upper coil and the lower coil; and a side surface of the workpiece. and a second conductor having one end connected to the lower coil and the other end connected to the other end of the high frequency power supply, the first heating part and the second heating part having a shape substantially corresponding to A high-frequency heating coil characterized by being arranged on both sides of the workpiece so as to be almost facing each other. (2) The high-frequency heating coil and a pair of cooling jackets are arranged to face each other with the first conductor and the second conductor interposed therebetween, and the cooling jackets are hollow and insulating, and the cooling jackets are hollow and insulating. and a surface hardening device, characterized in that a hardening coolant injection hole is provided on the surface facing the second conductor.