JPH0382713A - Induction hardening coil - Google Patents

Abstract

PURPOSE:To heat and harden columnar metallic members dissililar in diameter by means of the same high frequency coil by dividing semiannular parts of a coil for induction heating surrounding a columnar member at the central parts, respectively, and making the above respectively divided semiannular parts turnable at the time of hardening a columnar metallic member by means of high frequency induction heating. CONSTITUTION:A high frequency electric current is sent from a high frequency electric power source 30 to an induction coil body 10 made of steel tube covering the near-semicircular surface of a near-columnar metallic member 40 and consisting of semiannular parts 11A, 11B and pear-straight-line parts 12A, 12B connecting the above parts 11A, 11B, by which high frequency induced current is allowed to flow on the surface of the metallic member 40 to carrying out heating and hardening. At this time, semiannular parts 11A, 11B at both ends of the coil body 10 are opened to both sides by using screws 13 as fulcrums, respectively, and respective radii are changed to cover respective semicircular surfaces of columnar metallic members 40 dissimilar, to some degree, in diameter, and then, electrification is performed via the straight-line parts 12A, 12B and cooling water is introduced through feed water pipes, 24, 24, 14A1 and exhausted through drain pipes 14B1, 14B2, 14A2 to cool the coil. By this method, the columnar metallic members 40 dissimilar in diameter can be heated and hardened by means of induced current without replacing the coil 10.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an induction hardening coil used for surface hardening a substantially columnar work such as an automobile drive shaft.

<Prior Art> Conventionally, an induction hardening coil called a line coil has been used to perform surface hardening on substantially columnar workpieces such as automobile drive shafts. As shown in FIG. 6, this coil includes a pair of semi-annular parts 51 and 51 that surround a substantially columnar workpiece 40 to be induction hardened over approximately half the circumference at two positions in the axial direction of the workpiece 40; Part 5
1.51, and a pair of substantially straight portions 52.52 interconnecting corresponding end portions 52.51. During hardening, the high frequency power source 30 connected to one substantially straight section 52 is activated while the work 40 is being rotated. Then, a high frequency current is induced in the surface layer of the workpiece 40 by the high frequency current flowing through the pair of semicircular portions 51.51 and the pair of substantially straight portions 52.52. This induced high frequency current
Heat the surface layer evenly.

<Problems to be Solved by the Invention> With such an induction hardening coil, the diameter of the almost columnar workpieces that can be hardened with the coil is limited, so it is difficult to harden almost columnar workpieces with different diameters. In this case, a coil had to be manufactured according to the diameter. Therefore, the manufacturing cost of the coil is high, which has an adverse effect on the quenching cost. Furthermore, when hardening substantially columnar workpieces having different diameters, that is, when changing setups, the coil must be replaced, resulting in a decrease in work efficiency.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an induction hardening coil that can harden substantially columnar workpieces of different thicknesses without replacing the coil.

<Means for Solving the Problems> An induction hardening coil according to a first aspect of the present invention includes a pair of semi-annular parts that surround approximately half the circumferential surface of a substantially columnar workpiece to be induction hardened; a pair of substantially straight parts interconnecting corresponding ends of the parts, such that the pair of semi-annular parts can change the interval between the pair of substantially straight parts connected to both ends thereof. is divided between the two ends,
The gist of the configuration is that the divided semi-annular parts are rotatably connected to each other.

The induction hardening coil according to the second invention includes a pair of semi-annular parts that surround approximately half the circumference of a circumferential surface to be induction hardened of a substantially columnar workpiece, and opposing ends of the pair of semi-annular parts that are connected to each other. a pair of substantially linear parts connected to the semicircular parts, and the pair of semicircular parts are divided between both ends thereof so that the distance between the pair of substantially straight parts connected to both ends thereof can be changed. ,
The gist of the configuration is that the divided semi-annular parts are connected so that they can move toward and away from each other in parallel.

Effect> In both the first and second inventions, the interval between the pair of substantially straight portions can be changed depending on the thickness of the substantially columnar workpiece to be induction hardened. Therefore, even if the thickness of the workpiece changes, the distance between the workpiece and the substantially straight part can be maintained almost constant, so the peripheral surfaces of substantially columnar workpieces of different thicknesses can be hardened with the same coil without any problem. I can do it.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 4 are drawings for explaining an embodiment of the first invention, in which FIG. 1 is a perspective view of an induction hardened coil, FIG. 2 is a plan view of the main part thereof, and FIG. 3 is a front view of the main part, and FIGS. 4(a) and 4(b) are front views showing the state of use.

The coil body 10 of the induction hardened coil includes a pair of semi-annular parts 11A, IIB, a pair of substantially linear parts 12A, 12B installed between opposing ends of the semi-annular parts 11A, IIB. It becomes more. Both members are formed of rectangular tubular tubes made of conductive metal such as copper.

The semi-annular portion 11^ has a substantially semicircular shape and is divided into two arc-shaped members 11A1 and 11Az at the center. Semi-annular part 11
B is also approximately semicircular, with two arc-shaped members 11s in the center.
It is divided into 11Bz. Arc-shaped members 11A and 11
Az and the arcuate members 11B+ and 1182 are the semicircular portion 11A.

Screw 1 parallel to the axis of 11B (direction of arrow A in Figure 1)
3, and can be bent freely using the screw 13 as a fulcrum. Therefore, the substantially straight portion 12
The spacing between A and 12B is arbitrarily adjusted.

Arc-shaped member 11A, IIA! The connecting end portions of the pipes are closed and connected to the water supply pipe 14A1 and the drain pipe 14A2, respectively. The ends of the arcuate members 11A+ and 1lAz on the opposite side of the connection communicate with substantially straight parts 12A and 12B, respectively. The connection side ends of the arcuate members 11B+ and 1lfh are closed,
They are connected to drain pipes 14B+ and 14B2, respectively.

Arc-shaped member 11B.

The anti-connection side end portions of nBz are each substantially straight portions 12A.

It communicates with 12B. The substantially straight portions 12A and 12B are parallel to the axes of the semi-annular portions 11A and IIB, and the substantially straight portion 12B'' is divided into two approximately at the center, and the power feeding head 20 is connected to the connecting portion in this divided portion. 21.21.

The power supply head 20 has a sandwich structure in which an insulating plate 23 is sandwiched between conductive plates 22 and 22. Conductive plate 22゜2
A high frequency power source 30 is connected to the connecting portion 21.
, 21 are connected. Like the coil body 10, the connecting portion 21.21 is formed of a rectangular tubular thin tube made of a conductive metal such as copper. The above-mentioned one ends of the connecting parts 21, 21 are also connected to the water supply and drainage pipes 24, 24, and the other ends communicate with the two-divided substantially straight part 12B, respectively.

+ like this! In Kai's induction hardening coil, hardening of a substantially columnar workpiece 40 is performed as follows.

When the approximately columnar workpiece 40 has a circular cross section and its diameter is a standard value, that is, when the semicircular portions 11A and IIB can be processed in a normal state (semicircular state), the process shown in FIG. 4(a) is performed. As shown, the semi-annular parts 11A and IIB are in their normal state (
(a semicircular state), and the workpiece 40 is placed concentrically inside the semicircular state. As a result, the substantially straight portions 12A and 12B are located 180'' apart on the circumferential surface of the workpiece 40, and face the circumferential surface of the workpiece 40 at that position while maintaining a predetermined distance.

After setting the work 40, water is supplied from the water supply pipes 24, 24 and 14'AI, and the drain pre-clamps 14AZ, 14B
While draining water from + and 14B2, the work 40 is rotated and the high frequency power source 30 is activated. Such water supply and drainage water-cools the semi-annular portions 11A, IIB and the substantially straight portions 12A, 12B. A high frequency current is induced in the surface layer of the circumferential surface of the workpiece 40 by the high frequency current flowing through the substantially straight portions 12A, 12B and the semicircular portions 11A, IIB. This induced high-frequency current uniformly heats the surface layer of the circumferential surface of the workpiece 40 between the semi-annular parts 11A and 118 over the entire circumference.

If the diameter of the almost columnar workpiece 40 is larger than the standard value,
As shown in FIG. 4(b), arc-shaped members 11AI, 11
A2 and the arcuate members 11B+, 11Bz are opened to both sides using the screw 13 as a fulcrum. As a result, the substantially straight portion 12A,
The interval between 12B increases. In this way, the substantially straight portion 12A
,' By keeping the distance between 12B and the surface of the workpiece 40 almost constant and operating the high-frequency power supply 30 while rotating the workpiece 40 in this state, the surface layer is heated by high-frequency current in the same way as when the workpiece 40 has a standard diameter. heated.

Note that if the distance between the substantially straight portions 12A and 12B is widened,
A substantially straight portion 12A on the circumferential surface of the substantially columnar workpiece 40.

The mutual separation angle α of 12B increases to 180° as the spacing increases.
The angle gradually decreases from 150° to 120°. As a result, the coil efficiency decreases to some extent, but since the distance from the substantially straight portions 12A, 12B to the surface of the substantially columnar workpiece 40 hardly changes, there is no problem with the hardening itself.

Next, an embodiment of the second invention will be described. FIG. 5 is a front view of an induction hardened coil showing this embodiment.

A pair of semi-annular portions 11A of the coil body 10 (the semi-annular portion corresponding to the semi-annular portion 11B in FIG. 1 is omitted, but the fifth
The semicircular portion 11A (having the same structure as the semicircular portion 11A shown in the figure) is substantially U-shaped and designed to be sufficiently large for the substantially columnar workpiece 40. The semi-annular portion 11A has a pair of L branch members 12A at the center thereof.

It is divided into 12Az, a pair of L-shaped members 12AI,
1282 are connected by screws 13 at the split portions so that they can move toward and away from each other in parallel.

According to the induction hardening coil shown in FIG. 5, even if the distance between the substantially straight portions 12A and 12B increases as the diameter of the workpiece 40 increases, the substantially straight portions 12^ and 1 on the circumferential surface of the workpiece 40
The mutual separation angle of 2B remains at 180°. Further, a substantially columnar workpiece 4 is formed from the substantially straight portions 12A and 12B.
It goes without saying that the distance to the zero surface can be maintained constant, and even if the thickness of the workpiece 40 changes in this embodiment, it can be hardened uniformly in the same way as the workpiece 40 of standard diameter.

The induction hardened coil according to the present invention can be used not only for columnar workpieces having the same cross-sectional shape in the entire axial direction, such as drive shafts, but also for workpieces that have substantially different cross-sectional shapes in the axial direction, such as stepped shafts. It can also be applied to columnar workpieces. In this case, the substantially straight portions 12A and 12B of the induction hardened coil may be formed to substantially correspond to the outer shape of the stepped shaft or the like.

<Effects of the Invention> The induction hardening coil according to the present invention can harden substantially columnar workpieces of different thicknesses with the same coil without any problems, so it is possible to harden a wide variety of products with a small number of coils. can. Therefore, it is possible to reduce the manufacturing cost of the coil. Further, when hardening substantially columnar workpieces of different thicknesses, there is no need to replace the coil. That is, setup changes can be performed easily and quickly.

[Brief explanation of drawings]

1 to 4 are drawings for explaining an embodiment of the first invention, in which FIG. 1 is a perspective view of an induction hardened coil;
Fig. 2 is a plan view of the main part, Fig. 3 is a front view of the main part, and Figs. 4(a) and 4(b) are front views showing the state of use. When the workpiece has a standard diameter, b) indicates the case where the workpiece has a diameter larger than the standard diameter. FIG. 5 is a front view of an induction hardened coil showing an embodiment of the second invention, and FIG. 6 is a schematic diagram of a conventional induction hardened coil. IO...Coil body 11A, 11B...Semi-annular part 128, 13...20...30...40...12B...Substantially straight part, screw, power supply head, high frequency power supply, work

Claims (2)

[Claims] (1) A pair of semi-annular parts that surround approximately half the circumference of the circumferential surface to be induction hardened of a substantially columnar workpiece, and a pair of approximately linear parts that interconnect the corresponding ends of the pair of semi-annular parts. and the pair of semi-annular parts are divided between both ends thereof so that the distance between the pair of substantially straight parts connected to both ends thereof can be changed, and the divided semi-annular parts are An induction hardening coil characterized by being rotatably connected to each other. (2) a pair of semi-annular parts that surround approximately half the circumference of the circumferential surface to be induction hardened of a substantially columnar workpiece; and a pair of approximately straight parts that interconnect mutually corresponding ends of the pair of semi-annular parts. and the pair of semi-annular parts are divided between both ends thereof so that the distance between the pair of substantially straight parts connected to both ends thereof can be changed, and the divided semi-annular parts are An induction hardening coil characterized in that the coils are connected so that they can move toward and away from each other in parallel motion.