JP2002161311A - Induction heating and quenching process and heating coil for large spherical surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform induction heating and quenching over a large spherical surface by means of a small power capacity source. SOLUTION: A material to be quenched is rotated and the top spherical area 1, middle circumferential zone 2 and side circumferential zone 3 of a spherical work are dividedly quenched by use of respectively responding No.1 coil 10, No.2 coil 20 and No.3 coil 30 under movable quenching system. The No.1 and No.2 coils 10 and 20 respectively constitute a fan shaped coil that combines a short arc curved axial conductor along the spherical longitude and a short arc curved circumferential conductor along the latitude, thereby creating soft zones 1a and 2a of an equal width after quenching. The spherical work is cooled by coolants sprayed on it from the injection nozzles of magnetic flux focusing part located at the inner circumference of one or more of heating coils and the cooling jackets located behind the back side of heating coils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to induction heating of a large spherical surface for quenching a spherical surface of a member having a large spherical surface, for example, a large member having a large spherical surface of 500 mmφ such as a gripper jack used for a tunnel excavator. The present invention relates to a quenching method and a heating coil.

[0002]

2. Description of the Related Art In ordinary surface hardening of a spherical member, induction heating is performed while rotating an object to be heated by using a heating coil having a conductor having a curved line along the spherical surface in the axial direction, and after heating, cooling is performed. The method of quenching is taken. As an improvement, the applicant of the present invention has previously described the Japanese Utility Model Publication No.
No. 62 and Japanese Utility Model Publication No. 1-41922 have been disclosed.

In such a heating method, the material to be processed needs to rotate at a certain high speed in order to uniformly heat the heating section. However, for example, a shaft member having a weight of as much as 8 tons, such as the gripper jack member, is difficult to rotate at high speed due to rotational heating. Therefore, in such a large-sized member, moving quenching that moves and hardens while heating and cooling a portion to be processed is adopted.

[0004]

However, in the case of the above-mentioned large members, even with moving quenching, in order to heat the entire spherical surface with one coil at a time, an extremely large power facility is required. It is difficult to apply a sufficient heating load. For this reason, there is a problem that the heating temperature is partially uneven, the heating time is prolonged, and the thermal efficiency is reduced, and induction heating and quenching are almost impossible with ordinary equipment. Further, it is difficult to heat a large surface of a large spherical surface to a uniform temperature at a time, and it is difficult to obtain a uniform surface hardness.

Furthermore, when the spherical surface is moved and quenched with a coil of a conductor in which the top and side surfaces of the spherical surface disclosed in Japanese Utility Model Publication No. 1-41192 are described, the larger diameter of the side surface portion is larger than the smaller diameter circumference of the spherical top portion. Since the heating rate of the circumference is slow, the top part once quenched is reheated and tempered, and there is a problem that a high hardness cannot be obtained at the top part.

[0006] In general, in moving quenching, a soft zone is formed between the start of quenching and the end of quenching so that the quenching start portion is not reheated. This soft zone is desirably in the form of zones 1a and 2a having the same width and being parallel as shown in the upper part of FIG. 6XX. However, when the spherical surface is quenched by a conventional linear coil shown by a broken line below the line XX in FIG. 6, fan-shaped soft zones 1a 'and 2a' are not formed as shown in FIG.

On the other hand, in the case of quenching a large spherical surface, it is often sufficient to harden a portion for supporting the proof stress, even if the surface is not entirely quenched. Therefore, an object of the present invention is to provide a method and a heating coil for induction heating and quenching a large spherical surface, which can be quenched with a small-capacity electric power facility and have a soft zone of equal width.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a method for induction heating and quenching a large spherical surface according to the present invention comprises the steps of: It is characterized in that the crown circumference and the side circumference of the spherical surface are divided into at least two or more portions and divided and quenched. Therefore, the crown portion of the spherical surface to be hardened is hardened by the first coil. It is preferable to quench the circumference of the middle part between the crown and the side by the second coil and to harden the circumference of the side by the third coil.

That is, by dividing and moving and quenching the top, middle and side surfaces at least into at least two parts, it is possible to heat and quench a large spherical surface with small power equipment. Further, softening due to reheating of the crown as described above can be prevented, and uniform spherical hardening can be performed.

The large-sized induction heating coil for hardening is a planar heating coil having a curved conductor along the spherical surface to be hardened toward the heating surface, and the first and second coils are hardened.
The coil is formed by two axial conductors having a short arc along the longitude line of the spherical surface and a circumferential conductor having a short arc connecting the longitude lines of the two axial conductors along the latitude line of the quenched portion. A fan-shaped coil having a bottom side and a top side.

When the spherical surface is heated and quenched by a rectangular coil used for normal planar induction heating, the fan-shaped soft zone 1a shown in the lower part of line XX in FIG.
'Occurs. On the other hand, according to the coil of the present invention, since the lengths of the bottom side and the top side of the circumferential conductor are in a sector shape having a length corresponding to the interval between the longitude lines formed by the axial conductor, the X-axis of FIG. -As shown in the upper part of the X-ray, the soft zone 1a has the same width. Practically, the third coil may be a coil of a rectangular conductor along the sphere to be quenched instead of a fan.

Preferably, the first coil is a two-turn coil in which a small-diameter fan-shaped coil is arranged on the inner peripheral side of a large-diameter fan-shaped coil and both coils are connected in series. In this case, the magnetic flux density can be increased, and the heating efficiency can be increased.

Preferably, at least one or more of the heating coils is provided with a magnetic flux concentrating material on the inner peripheral side of the coil. In this case, by appropriately arranging the magnetic flux concentration material, it is possible to eliminate uneven heating.

Further, it is desirable that the magnetic flux concentrator is provided with a hollow portion into which the cooling liquid is introduced, and an injection port for injecting the cooling liquid introduced into the hollow portion onto the spherical surface to be quenched. In this way, the cooling liquid can be directly and uniformly sprayed on the heating surface immediately after the heating, so that rapid cooling is easy and uniform hardening hardness can be obtained.

[0015] Further, by providing a cooling jacket for injecting a cooling liquid to the rear side where the heating coil moves,
In moving quenching, rapid cooling after heating is further facilitated, and uniform quench hardness is obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. FIG. 1 is a diagram for explaining induction heating and quenching according to the present invention, FIG. 2 is a perspective view of a first coil for heating the circumference of the crown of the sphere to be quenched, and FIG. 3 is the circumference of the middle between the crown and the side. FIG. 4 is a perspective view of a third coil for heating the circumference of the side surface portion similarly. 5 is a partial cross-sectional view showing the structure of the magnetic flux concentration material of the present invention, FIG. 6 is a diagram showing a comparison of the shape of the soft zone between the present invention and conventional quenching, and FIG.
FIG. 8 is a diagram showing the shape of the member to be quenched used in the embodiment of the present invention.

Referring to FIG. 1, induction heating and quenching according to the present invention is for quenching a hardened spherical surface of a head W1 of a hardened member (hereinafter referred to as a workpiece) W. As shown in FIG. 8, an example of the workpiece has a spherical surface diameter of 590 mm and a length of 330 mm.
It is a large member of 0 mm and 8 tons.

The quenching method is as follows. First, the work W is rotated once while the top of the spherical surface to be quenched of the work W is heated and cooled by the first coil 10 and the top of the work W is moved and quenched to form the quenched surface 1. Let it. Next, the middle part between the top and the side is the second coil 2
Similarly, the work W is rotated while heating and cooling by 0 to form a quenched surface 2 by moving and quenching the intermediate portion, and then the work W is similarly heated and cooled by the third coil 30 on the side surface portion 3. Is rotated to form a quenched surface 3 by moving quenching.

At this time, at the position of one rotation, the soft zones 1a, 1a,
2a and the like are formed. In the present embodiment shown in FIG. 1, the through hole P is provided in the spherical portion of the work, so that the through hole P
Are formed on both sides of the soft zone. Soft zones are also formed between the quenching surface 1 at the crown and the quenching surface 2 at the middle, and between the quenching surface 2 at the middle and the quenching surface 3 at the side surface. The hardened surfaces 1, 2,
It is desirable that the positions of the soft zones 1a, 2a, and 3a of the 3 are shifted in the circumferential direction as shown in the figure. Details of this soft zone will be described later.

The first coil 10 of the present invention shown in FIG. 2 is a fan-shaped coil, and a large-diameter fan-shaped coil in which circumferential conductors 11a, 11b and 13 and axial conductors 12 and 14 are alternately connected; Circumferential conductor 15 disposed on the inner peripheral side
a, 15b and 17 and the similar small-diameter sector coils in which the axial conductors 16 and 18 are alternately connected are 11b and 15
It consists of a two-turn coil connected in series by a. Then, the terminal T11 is connected to the lead portion L11 connected to the circumferential conductor 11a of the large diameter coil, and the terminal T12 is connected to the lead portion L12 connected to the circumferential conductor 15b of the small diameter coil. , T1
2, power is input.

The conductors of these coils are curved along the spherical surface so as to form a predetermined gap with the spherical surface of the work. Axial conductors 12, 14 for large and small diameter coils
And 16, 18 are each formed of a short arc-shaped conductor curved along the longitude line of a spherical surface as shown by broken lines in the figure, and are arranged at predetermined intervals.

Further, the circumferential conductors 11a, 11b and 13 and 15a, 15b and 17 of the large-diameter coil and the small-diameter coil are used.
Is also composed of short arc-shaped conductors curved along the latitude line on the spherical surface at each position, as indicated by broken lines, spaced at the width of the quenched surface, and both ends are connected to the axial conductor. .
As a result, the length of the circumferential conductor becomes a length corresponding to the interval between the longitude lines formed by the axial conductors, and the coil forms a fan shape. Then, each conductor is connected to the conductor 11a-12-13-1 from the lead L11 as indicated by the arrow.
4-11b-15a-16-17-18-15b are connected so as to flow to the lead L12.

The second coil 20 shown in FIG. 3 is the same as the first coil, but the second coil 20 is a single-turn coil. Each of the axial conductors 22 and 24 is a short arc-shaped conductor having a curved line along the longitude line of the intermediate surface of the spherical surface. Further, the circumferential conductors 21a, 21b and 23 are formed of short arc-shaped conductors having a curved line along the latitude line of the intermediate surface 2 of the spherical surface, and the length of each circumferential conductor is determined by the longitude formed by the axial conductor. It has a length corresponding to the interval between the lines. Thereby, the second coil 2
0 also forms a fan-shaped coil. And each conductor is
It is connected so that the current flows in the arrow in the figure.

A third coil 30 for heating the side surface of the spherical surface shown in FIG.
2, 34 extend over the upper hemisphere and the lower hemisphere, and may be a rectangular coil for practical use. Others are the second coil 20
Is the same as

As shown in FIG. 5, the second coil 20 is provided with a magnetic flux concentration member on the inner peripheral side of the coil. FIG.
(A) is a partial cross-sectional view of a plane of the magnetic flux concentration member mounted on the second coil 20, and (b) is a YY cross-sectional view of FIG.

In the figure, the magnetic flux concentrator 40 comprises a base 41 and a lid 42. A hollow portion 41a is provided in the base body 41.
Are dug, and a large number of injection ports 41b for injecting the cooling liquid from the hollow portion 41a toward the work are penetrated. A magnetic lid 42 is adhered on the base body 41,
a forms a cavity. An introduction tube 43 is adhered to the lid 42. Thus, after the work is heated, the cooling liquid introduced into the hollow portion 41a from the introduction pipe 43 is jetted from the injection port 41b to the work surface to be rapidly cooled.

As the cooling means, in addition to cooling from the magnetic flux concentrating material, a cooling jacket shown in FIG. 7 is mounted. FIG. 7 is a diagram showing the cooling jacket mounted on the third coil 30, but the same applies to the first and second coils. That is, a cooling jacket 45 is disposed behind the conductors 32 and 34 of the third coil 30 in the traveling direction, and the workpiece is heated by the third coil while being moved, and immediately cooled and quenched by the cooling jacket 45. is there.

The cooling jacket 45 is provided with an injection port 47 in a hollow tube 46 having a triangular cross section disposed parallel to the conductor 34 in the rearward direction of the third coil 30 in the traveling direction. The cooling liquid introduced into the hollow portion is jetted from the jet port 47 onto the work to cool it.

The quenching operation using the quenching coil having the above structure will be described below with reference to FIGS. First, the terminals T11 and T12 of the first coil 10 are connected to a high-frequency power supply (not shown), and the conductors 11a, 11b, 12, 13, 1
4 and the like are arranged at predetermined positions on the top of the head so as to have a predetermined distance from the hardened spherical surface of the work W. Then, electric power is input to the terminals T11 and T12, and the crown is induction-heated. When the surface to be quenched rises to the quenching temperature, the work is rotated and the surface heated by the cooling jacket 45 is cooled and quenched. Thereafter, the work is rotated at such a speed that the quenched surface is heated to the quenching temperature, and the quenching is performed by heating and cooling while continuously rotating and moving. When the work rotates once,
The rotation of the workpiece is stopped by forming a soft zone 1a as shown in FIGS. Thereby, a quenched and hardened surface as shown in the upper part of line XX in FIG. 6 is formed.
Since the fan-shaped heating coil is used, the width of the soft zone 1a becomes equal as shown in the figure. At the time of cooling, the second coil also injects the cooling liquid from the injection port 41b of the magnetic flux concentrator 40 to cool, so that a more rapid cooling effect can be obtained.

After the quenching surface 1 at the top is formed, the quenching surface 2 at the intermediate portion is formed. Similarly to the first coil, the second coil 20 is connected to a high-frequency power source (not shown), and is disposed at a predetermined position in an intermediate portion of the work. Then, the quenching surface 2 at the intermediate portion is formed by the same operation as the quenching surface 1 at the top of the head. Also in this case, the soft zone 2a has the same width. In addition,
As described above, it is desirable that the positions of the soft zone 1a on the quenching surface 1 at the top and the soft zone 2a on the quenching surface 2 at the middle be shifted in the circumferential direction.

The quenching surface 1 at the top and the quenching surface 2 at the middle
Is formed, the quenching surface 3 on the side surface is formed by the third coil by the same operation. Since the through-hole P is provided in the spherical portion of the work of this embodiment in FIG. 1, the soft zones 3a are formed on both sides of the hole (FIG. 6 shows a case without a hole).

The quenching operation is completed by quenching the quenched surfaces 1, 2, and 3 by the above method. The shape of the quenching surface is, as shown in the figure, between the quenching surface 1 at the top and the quenching surface 2 at the intermediate portion, and between the quenching surface 2 at the intermediate portion and the quenching at the side portion, in addition to the soft zone. The surface also has a soft zone formed between the surface 3.

[Example] An example in which quenching was performed under the following conditions by the above method will be described. Work dimensions: 3300 mm long member with a through-hole P on the 590 mm diameter spherical head shown in FIG. 8, about 8 tons Work material: SCM440 Heating conditions: As shown in Table 1

[0034]

[Table 1]

The results of the quenching are shown in FIGS.
It is shown in Table 3. FIG. 9 is a diagram showing details of the side surface shape of the quenched surface,
FIG. 10 is a Z view of FIG. Table 2 shows standard values and measured values of the dimensions of the quenched surfaces in FIGS. As can be seen from the table, the method of the present invention provided a predetermined width of the quenched surface and a target soft zone.

[0036]

[Table 2]

Table 3 shows the measured values of the quench hardness at the respective positions shown in FIGS. 9 and 10, and the quench hardness also satisfies the standard value. As described above, as can be seen from these tables, according to the present invention, the quenched surface dimensions and quenched hardness both sufficiently satisfy the standard,
It turns out that the planned soft zone can be obtained.

[0038]

[Table 3]

In this embodiment, the spherical surface is divided into three parts, namely, the top part, the middle part, and the side part, and is divided and quenched. However, depending on the size of the spherical surface, the top part and the middle part are quenched at once and combined with the side part. Quenching can be performed in two parts, and quenching in four or more parts can be performed.

[0040]

As described above, according to the method and the coil for induction heating and quenching a large spherical surface of the present invention, the member to be quenched is rotated by the first coil, the second coil, and the third coil while rotating the member. Since the top circumference, the middle circumference, and the side circumference of the hardened sphere are divided and quenched, the large sphere can be induction-hardened with equipment having a small capacity.

The coil used is a planar heating type coil having a curved conductor along the spherical surface to be quenched toward the heating surface. Since the first and second coils are fan-shaped coils, they are conventional rectangular coils. Unlike a coil, a soft zone having an equal width can be obtained without generating a fan-shaped soft zone.

The first coil uses a two-turn coil,
At least one or more coils are provided with a magnetic flux concentrating material (the second coil in the present embodiment), so that an appropriate magnetic flux for uniformly heating the heating surface can be obtained. Since the injection port for injecting into the hardened spherical surface is provided, rapid cooling is easy and uniform hardening hardness is obtained. Further, a cooling jacket for injecting a cooling liquid is provided on the rear side of the heating coil to perform injection cooling, so that more complete quenching cooling can be performed.

As described above, induction heating and quenching of a large spherical surface, which has conventionally been difficult to quench, can be performed easily with equipment having a relatively small capacity, which can contribute to cost reduction of a large spherical member.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating induction heating quenching according to an embodiment of the present invention.

FIG. 2 is a perspective view of a first coil that heats the circumference of the crown of the spherical surface to be hardened.

FIG. 3 is a perspective view of a second coil for heating a circumference of an intermediate portion of a quenched spherical surface.

FIG. 4 is a perspective view of a third coil that heats a circumference of a side surface of a quenched spherical surface.

FIG. 5 is a partial cross-sectional view showing a structure of a magnetic flux concentration member according to the embodiment of the present invention.

FIG. 6 is a diagram showing a comparison of the shape of a soft zone between the present invention and conventional quenching.

FIG. 7 is a diagram illustrating an example of a cooling unit according to the embodiment of the present invention.

FIG. 8 is a view showing the shape of a member to be quenched used in the embodiment of the present invention.

FIG. 9 is a view showing details of a side surface shape of a quenched surface according to the embodiment of the present invention.

FIG. 10 is a Y view of FIG. 9;

[Explanation of symbols]

1 Quenched surface at top, 2 Quenched surface at middle, 3 Quenched surface at side, 1a, 2a, 3a, soft zone, 10 first coil, 11a, 11b, 15a, 15b, 13, 17 Circumferential conductor , 12, 14, 16, 18 axial conductor, L
11, L12 lead, 20 second coil, 21a, 21
b, 23 circumferential conductor, 22, 24 axial conductor, L2
1, L22 lead, 30 third coil, 31a, 31
b, 33 circumferential conductor, 32, 34 axial conductor, L
31, L32 lead, 40 magnetic flux concentration material, 41 base body, 41a hollow portion, 41b injection port, 42 lid, 43
Inlet tube, 45 cooling jacket, 46 hollow tube, 47
Injection port, 48 Inlet pipe W Work (hardened member), P
Through pin hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 6/44 H05B 6/44 F term (Reference) 3K059 AA09 AA10 AB28 AD05 AD32 CD48 CD52 CD64 CD65 CD79 4K042 AA25 BA10 BA13 DA01 DB01 DD04 DE02 DF02

Claims (7)

[Claims] 1. A quenched member having a large spherical surface is rotated and quenched by moving so that the crown circumference and the side surface circumference of the quenched spherical surface are divided into at least two or more parts and divided and quenched. A method for induction heating and quenching a large spherical surface. 2. When rotating and quenching a member to be quenched having a large spherical surface, a first coil quenches the circumference of the crown of the sphere to be quenched, and the second coil illuminates the crown and side portions. 2. The method of induction heating and quenching of a large spherical surface according to claim 1, wherein the middle part is hardened, and the side surface part is hardened by a third coil. 3. When rotating and quenching a member to be quenched having a large spherical surface, a first coil quenches the circumference of the crown of the sphere to be quenched, and a second coil forms the crown and side portions. In the induction heating coil, which quenches the circumference of the middle part of the above and hardens the circumference of the side part by the third coil, the heating coil is a conductor having a curved surface along the spherical surface to be hardened toward the heating surface. Wherein the first and second coils are two axial conductors having a short arc-shaped curve along a spherical longitude line, and the two axial conductors along a latitude line of a quenched portion. A large spherical induction heating coil, which is a fan-shaped coil having a bottom side and a top side formed by a circumferential conductor having a short arc-shaped curve connecting between longitude lines. 4. The first coil is a two-turn coil in which a small-diameter fan-shaped coil is disposed on the inner peripheral side of a large-diameter fan-shaped coil and both coils are connected in series. 2. A large spherical induction heating coil according to claim 1. 5. The large spherical induction heating coil according to claim 3, wherein at least one or more coils of the heating coil are provided with a magnetic flux concentration material on an inner peripheral side of the coil. . 6. The magnetic flux concentrator is provided with a hollow portion into which a cooling liquid is introduced, and an injection port for injecting the cooling liquid introduced into the hollow portion onto a quenched spherical surface. The large spherical induction heating coil according to any one of claims 3 to 5. 7. The large spherical induction heating coil according to claim 3, wherein the heating coil is provided with a cooling jacket for spraying a cooling liquid on a rear side of the heating coil.