JP2632127B2 - High frequency whole inner peripheral surface heating coil for cylindrical work and high frequency whole inner peripheral surface heating method for cylindrical work - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency whole inner peripheral surface heating coil for heating a whole inner peripheral surface at a shallow depth in order to form a shallow hardened layer on the entire inner peripheral surface of a thin cylindrical work. The present invention relates to a high-frequency whole inner peripheral surface heating method.

[0002]

2. Description of the Related Art In the following, a thin, substantially cylindrical work is taken as an example of a cylindrical work, and a shallow hardened layer is formed on the entire inner peripheral surface of a cylindrical work (hereinafter, the cylindrical work is also simply referred to as a work). In addition, a conventional high-frequency whole inner peripheral surface heating coil for induction heating the entire inner peripheral surface at a shallow depth (hereinafter, the high frequency total inner peripheral surface heating coil is also simply referred to as a heating coil) and a cylindrical work using the heating coil A method for heating the inner peripheral surface will be described with reference to the drawings. FIG. 2 is an explanatory longitudinal sectional view of a work and a conventional heating coil.

[0003] The entire inner peripheral surface 25 between one opening 26 and the other opening 27 of the work 20 is a rotationally symmetric body centered on the axis 29, and has a columnar shape formed on the opening 26 side. Hole 21 (first
The inner peripheral surface 23 (the first inner peripheral surface) of the hole 20 and the opening 27 side of the work 20 are formed so as to communicate with the hole 21 and the diameter at the opening 27 is larger than the diameter of the hole 21. Frustoconical hole 22 (second hole)
Inner peripheral surface 24 (second inner peripheral surface), and the entire inner peripheral surface 25 is subjected to high-frequency induction heating for quenching, for example.

[0004] The heating coil 10A for high-frequency induction heating of the entire inner peripheral surface 25 is formed of a good conductive circular metal tube, and when the heating coil 10A is disposed in the work 20, the entire inner peripheral surface 25 of the work 20 is heated. A linear lead conductor 11 (first lead conductor) disposed at the position of the shaft core wire 29 of the
One end is connected to the tip of the side, surrounding the shaft core wire 29,
And with a constant diameter slightly smaller than the diameter of the inner peripheral surface 23, almost open
Heating conductor 13 spirally wound from 27 to opening 26
And the lead conductor 12 (second
(Lead conductor) and a disk-shaped magnetic core 15 made of ferrite or the like.

[0005] When the heating coil 10A is inserted into the work 20, the core 15 is positioned so as to be opposed to the opening 26 with an appropriate gap therebetween. , 12 are adhesively fixed. The core 15 is
This has the function of making the thickness of the hardened layer 42 formed near the opening 26 the same as the thickness of the hardened layer 42 in the other portions.

To harden the entire inner peripheral surface 25, first, work
20 is placed on the work receiver 30 so that the axis 29 is vertical, and the heating coil 10A is lowered from above to
After inserting the heating conductor 13 close to the entire inner peripheral surface 25,
For example, generated by a vacuum tube transmission circuit (not shown)
For high frequency induction hardening at 200 kHz, a relatively high frequency high frequency current is applied to the heating coil 10A. The reason why the high-frequency current having a high frequency is supplied in this manner is to make the heating depth of the entire inner peripheral surface 25 shallow.

When energization of the heating coil 10A is started,
The work receiver 30 is rotated about the axis 29 by a mechanism (not shown), for example, in the direction of arrow R. When the energization for a predetermined time is completed, the heating coil 10A is raised, and then a quenching liquid is jetted from a jacket (not shown) to the entire inner peripheral surface 25 to be cooled, and a hardened layer 42 is formed to form the hardened layer 42. Complete quenching. Thereafter, the rotation of the work 20 is stopped, and the work 20 is removed from the work receiver 30.

[0008]

However, the hardened layer 42 formed on the entire inner peripheral surface 25 of the work 20 in this manner is
As shown in FIG. 2, the inner peripheral surface 23 has a uniform depth,
Generally, the inner peripheral surface 24 is slightly shallower as approaching the opening 27, that is, the average depth is smaller than that of the inner peripheral surface 23. The larger the difference between the maximum value and the minimum value of the diameter of the inner peripheral surface 24, the smaller the average depth of the hardened layer 42 on the inner peripheral surface 24.

Therefore, in a portion corresponding to the inner peripheral surface 24 of the heating conductor 13, the distance between turns, that is, the winding pitch of the spirally wound heating conductor 13 is shortened to reduce the inner peripheral surface 24. The crossing magnetic flux may increase, but the heating coil 20
It takes a lot of time to manufacture the

In order to save this trouble, the energizing current of the heating coil 20 is increased, or the energizing time to the heating coil 20 is increased, so that the hardened layer 42 formed on the inner peripheral surface 24 is formed.
In such a case, a hardened layer 42 deeper than necessary is formed on the inner peripheral surface 23. In addition to lowering the product value, an extra hardened layer is formed on the inner peripheral surface 23,
Useless power is consumed.

The present invention has been made in view of the above circumstances, and has a first inner peripheral surface of a substantially cylindrical first hole formed on one opening side of a cylindrical work, and the other of the work. And the second inner peripheral surface of the substantially frusto-conical second hole formed so as to communicate with the first hole and to have the diameter at the other opening larger than the diameter of the first hole. It is an object of the present invention to provide a heating coil and a heating method capable of heating the entire inner peripheral surface of the work to a uniform depth.

[0012]

According to a first aspect of the present invention, there is provided a heating coil comprising: a first inner peripheral surface of a substantially cylindrical first hole formed on one opening side of a cylindrical work; The diameter of the other opening is the first so as to communicate with the first hole on the opening side.
A heating coil for high-frequency induction heating the entire inner peripheral surface of the work, the second inner peripheral surface being formed in a substantially truncated conical second hole having a diameter larger than the diameter of the hole; A first lead conductor disposed substantially at the position of the axis of the first lead conductor, one end of the first lead conductor being connected to the other end of the first lead conductor on the other opening side, surrounding the axis, and A heating conductor spirally wound from the other opening to the one opening with a constant diameter slightly smaller than the diameter of the inner peripheral surface, and a second lead conductor connected to the other end of the heating conductor And a magnetic core mounted so as to cover an outer peripheral surface of a portion substantially corresponding to the second inner peripheral surface of the first lead conductor partially or entirely in a circumferential direction of the outer peripheral surface. I have.

According to a second aspect of the present invention, in the heating method, a first inner peripheral surface of a substantially cylindrical first hole formed on one opening side of the cylindrical work, and a first hole formed on the other opening side of the work. And the second inner peripheral surface of the substantially frustoconical second hole formed so that the diameter at the other opening is larger than the diameter of the first hole. A first linearly arranged first lead conductor disposed substantially at the position of the axis of the entire inner peripheral surface, and one end connected to the other open end of the first lead conductor; A heating conductor surrounding the core wire and having a fixed diameter slightly smaller than the diameter of the first inner peripheral surface and spirally wound from the other opening to the one opening substantially; and the other end of the heating conductor And the outer periphery of a portion substantially corresponding to the second inner peripheral surface of the first lead conductor A high-frequency induction heating by a heating coil having a magnetic core mounted so as to partially or entirely cover the outer peripheral surface in the circumferential direction of the outer peripheral surface, and the thickness of the core and the core The length of the first lead conductor in the longitudinal direction, the mounting position of the core in the longitudinal direction of the first lead conductor, and the mounting range of the core in the circumferential direction of the first lead conductor are adjusted in advance. By doing so, the heating depth of the entire inner peripheral surface is made substantially uniform.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the heating coil according to the present invention will be described below with reference to the drawings. FIG. 1A is an explanatory longitudinal sectional view of the heating coil and the work, FIG. 1B is a perspective view of a core mounted on a first lead conductor, and FIG. 1C is an explanatory sectional view taken along line AA of FIG. FIG. The work 20 described above with reference to FIG. 2 was used as the work.

The heating coil 10 of the present embodiment differs from the heating coil 10A already described in FIG. 2 only in the following points. Therefore, only the different points will be described, and the description of the same points will be omitted. As shown in FIGS. 1A to 1C, the heating coil 10
A core 16 made of a magnetic material such as ferrite having a thickness t and a length L in the direction of the axis 29 is attached to a lower portion of the lead conductor 11. When the heating coil 10 is inserted into the inside of the work 20 so as to approach and face the entire inner circumferential surface 25 of the work 20, the upper end of the core 16 is moved to the boundary 28 between the inner circumferential surface 23 and the inner circumferential surface 24. Is mounted on the lead conductor 11 so as to be at a distance d. Further, as shown in FIG. 1C, the core 16
Are mounted over the range of the angle θ in the circumferential direction of the outer peripheral surface of

The angle θ, the thickness t of the core 16, the length L of the core, and the distance d are determined in advance by performing a test.
The average depth of the hardened layer 41 formed on the inner circumferential surface 23 is the hardened layer 41.
Each is adjusted to an optimal value so as to be almost equal to. The angle θ is usually selected from a range of 60 degrees to 360 degrees.

Next, in order to quench the entire inner peripheral surface 25 of the work 20 with the heating coil 10, the heating coil 10 is inserted into the work 20 in the same manner as with the conventional heating coil 10A. After being arranged close to the surface 25, while rotating the work 20 about the axis 29 in the direction of the arrow R, for example, 200 kHz
A high-frequency current is applied to the heating coil 10 for a predetermined time.

At this time, since the core 16 is provided on the lead conductor 11, the density of the synthetic magnetic flux crossing the inner peripheral surface 24 is larger than in the case where the conventional heating coil 10A without the core 16 is used. And, as mentioned above,
Since the adjustment of the angle θ, the thickness t, the length L, and the distance d of the core 16 has been performed in advance, the average heating depth of the inner peripheral surface 24 is substantially the same as that of the inner peripheral surface 23, that is, The depth of the hardened layer 41 formed by the uniform heating depth of the peripheral surface 25 is also uniform.

[0019]

As described above, in the heating coil according to the first aspect, the first inner peripheral surface of the substantially cylindrical first hole formed on one opening side of the cylindrical workpiece and the other of the workpiece. And the second inner peripheral surface of the substantially frusto-conical second hole formed so as to communicate with the first hole and to have the diameter at the other opening larger than the diameter of the first hole. A heating coil for high-frequency induction heating of the entire inner peripheral surface of the work, and substantially corresponds to the second inner peripheral surface of the substantially linear first lead conductor disposed substantially at the axial center line position on the entire inner peripheral surface of the work. A magnetic core mounted so as to partially or entirely cover the outer peripheral surface of the portion to be formed in the circumferential direction of the outer peripheral surface. The magnetic flux crossing the surface is increasing.

Accordingly, the thickness substantially corresponds to the thickness of the core, the length of the core in the longitudinal direction of the first lead conductor, the position of the core in the longitudinal direction of the first lead conductor, and the second inner peripheral surface of the first lead conductor. By adjusting at least one of the core mounting ranges in the circumferential direction of the outer peripheral surface of the portion in advance, the average heating depth of the second inner peripheral surface is increased to be substantially the same as the first inner peripheral surface. Therefore, the heating depth of the entire inner peripheral surface of the work is also substantially uniform.

In the heating method according to the second aspect, when the entire inner peripheral surface of the work is heated using the heating coil according to the first aspect, the thickness of the core and the length of the core in the longitudinal direction of the first lead conductor are set. The position of the core in the longitudinal direction of the first lead conductor,
By adjusting at least one of the core mounting ranges in the circumferential direction of the outer peripheral surface of the portion substantially corresponding to the second inner peripheral surface of the first lead conductor, the average of the second inner peripheral surface is adjusted. Since the heating depth can be increased to be substantially the same as the first inner peripheral surface, the heating depth of the entire inner peripheral surface of the work can be made substantially uniform.

[Brief description of the drawings]

FIG. 1 (a) is a longitudinal sectional view of a cylindrical work and a high-frequency whole inner peripheral surface heating coil of one embodiment of the present invention, and FIG. 1 (b) is a view of a core mounted on a first lead conductor of the heating coil. Perspective view,
(C) is an explanatory sectional view taken along line AA of (b).

FIG. 2 is an explanatory longitudinal sectional view of a cylindrical work and a conventional high-frequency whole inner circumferential surface heating coil for heating the entire inner circumferential surface of the work;

[Explanation of symbols]

 10 Heating coil 11, 12 Lead conductor 13 Heating conductor 16 Core 20 Cylindrical workpiece 21, 22 Hole 23, 24 Inner peripheral surface 25 Total inner peripheral surface 26, 27 Opening 28 Boundary line 29 Core axis

Claims (2)

(57) [Claims] 1. A first inner peripheral surface of a substantially cylindrical first hole formed on one opening side of a cylindrical work, and the other opening side of the work is communicated with the first hole and on the other side. Heating for high frequency induction heating of the entire inner peripheral surface of the work comprising the second inner peripheral surface of the second hole having a substantially frustoconical shape formed so that the diameter at the opening is larger than the diameter of the first hole. In the coil, a substantially linear first line disposed substantially at the axial center line position of the entire inner peripheral surface.
A lead conductor, one end of which is connected to a distal end portion of the first lead conductor on the other opening side, surrounding the axis;
A heating conductor wound spirally from the other opening to the one opening substantially at a constant diameter slightly smaller than the diameter of the first inner peripheral surface, and connected to the other end of the heating conductor; A second lead conductor and a magnetic core mounted so as to cover an outer peripheral surface of a portion substantially corresponding to the second inner peripheral surface of the first lead conductor partially or entirely in a circumferential direction of the outer peripheral surface; And a high-frequency entire inner peripheral surface heating coil for a cylindrical work. 2. A first inner peripheral surface of a substantially cylindrical first hole formed on one opening side of a cylindrical work, and the other opening side of the work is communicated with the first hole and on the other side. The entire inner peripheral surface of the work, which is composed of a second inner peripheral surface of a substantially truncated conical second hole formed so that the diameter at the opening is larger than the diameter of the first hole, A substantially linear first lead conductor disposed substantially at the position of the axis of the surface, one end of which is connected to a tip portion of the first lead conductor on the other opening side, surrounding the axis, and (1) a heating conductor having a constant diameter slightly smaller than the diameter of the inner peripheral surface and spirally wound substantially from the other opening to the one opening, and a second lead connected to the other end of the heating conductor; A conductor and an outer peripheral surface of a portion substantially corresponding to the second inner peripheral surface of the first lead conductor are arranged in a circumferential direction of the outer peripheral surface. A heating method for high-frequency induction heating by a heating coil provided with a magnetic core mounted so as to cover a part or the entire circumference thereof, and
The thickness of the core, the length of the core in the longitudinal direction of the first lead conductor, the mounting position of the core in the longitudinal direction of the first lead conductor, and the mounting range of the core in the circumferential direction of the first lead conductor. And heating the entire inner peripheral surface substantially uniformly by adjusting at least one of the inner peripheral surfaces in advance.