JPH03183724A - Semiopen induction hardening coil - Google Patents

Abstract

PURPOSE:To form a hardened surface layer of a uniform depth in the whole of a work by arranging plural high frequency heating coils having a prescribed shape so that the circular surface of the work can be heated with the separate coils. CONSTITUTION:Thin semiopen induction hardening coil is composed of a first heating coil 51, a second heating coil 52 having the same shape as the coil 51, a coil 53 connecting one end of the coil 51 to one end of the coil 52, a pair of power supplying coils 54, 55 and a core 59 and high frequency voltage 40 is impressed on ends of the coils 54, 55. The first coil 51 is positioned at one side of the circular surface of a work 10 to be hardened and has the shape of a circular are corresponding to about 1/4 of a circle. The core 59 is formed so as to cover the side faces of the coils 51, 52, 53 not confronting the circular surface to be hardened.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a semi-open induction hardening coil, and particularly relates to a semi-open induction hardening coil, and particularly to an annular hardening surface of a workpiece (object to be hardened) (for example, a pin or journal of a crankshaft). This relates to a semi-open induction hardening coil that hardens the surface of

<Prior Art> Hereinafter, a conventional technology will be described with reference to the drawings, taking as an example the case of hardening a bottle of a crankshaft. Fig. 6 is a perspective view of a conventional semi-open induction hardening coil (excluding the core), and Fig. 7 is a vertical cross-sectional view of the bottle and the sixth half-open induction hardening coil in the state of heating a workpiece. A- in the diagram
A sectional view taken along the line A, and FIG. 8 is a side view of the pin.

As shown in FIG. 6, the conventional semi-open induction hardened coil 30 includes a hollow heating coil 33, hollow power supply coils 31 and 32 connected to both ends of the heating coil 33, respectively.
Power feeding ends 311.321 of power feeding coils 31.32 connected to high frequency power source 40, and coolant supply pipes 41.321 connected to power feeding ends 311.321, respectively. A coolant discharge pipe 42;
A pair of cores 34 shown in FIG. 7 are bonded together so as to sandwich the heating coil 33 and power supply coils 31 and 32 from both sides.
It is equipped with Then, the hollow part 35 of the heating coil 33
The hollow portion 36 of the feeding coil 31 and the hollow portion (not shown) of the feeding coil 32 serve as passages for the cooling liquid of the semi-open induction hardening coil 30.

<Problem to be solved by the invention> However, the surface 11 of the pin 10 of the crankshaft
In order to form a hardened layer on the surface 11, the semi-open induction hardened coil 30 is arranged to face the surface 11.
When the heating coil 33 is hardened, the induced current is often concentrated at approximately the center of the surface 11, even though the groove 38 is formed in the heating coil 33 to form a hardened layer with a uniform depth. , as shown in FIG. 7, a hardened layer 12 having a narrow width and a non-uniform depth is formed, the depth of which is greater in the central portion than in the peripheral portion. It will no longer be possible to have it.

In addition, if the bottle 10 is provided with holes 19, etc. that serve as passages for lubricating oil, the formed hardened N12a is
As shown in the figure, the width around the hole 19 increases, and after hardening,
This poses a problem in forming, for example, the groove 18 in the vicinity of the hardened layer 12a.

The present invention has been devised in view of the above circumstances, and is a semi-open induction hardening method capable of forming a hardened layer of a predetermined width and uniform depth on the annular surface formed on the circumferential surface of a workpiece. The purpose is to provide coils.

Means for Solving the Problems> In order to solve the above problems, the semi-open induction hardening coil of the present invention has a structure in which the semi-open induction hardened coil of the present invention has an annular recess formed on the circumferential surface of a workpiece, on one side of which is close to the bottom surface of the recess. a first heating coil having an arc shape of approximately 174 yen or smaller than 1/4 yen, and a first heating coil disposed close to the bottom surface on the other side of the recess; a second heating coil having the same shape as the coil; a connecting coil disposed close to the bottom surface and connecting one ends of the first and second heating coils; A pair of power supply coils connected to both ends of the heating coil and formed so that the other ends are close to each other, and a surface of the first and second heating coils and the connecting coil that is not opposed to the bottom surface is covered. A high frequency voltage is applied between the other ends of the feeding coil.

Effect> The workpiece is rotated, and the cooling liquid is passed through the first and second heating coils and the power supply coil. A high-frequency current generated by a high-frequency power supply is applied to the power supply coil, the first heating coil, and the second heating coil. One side of the bottom surface of the recess of the workpiece is heated by an induced current by the first heating coil, the other side by an induced current by the second heating coil, and the central part is heated by an induced current by the connecting coil. Then, a hardening coolant is injected onto the workpiece, and a hardened layer having a predetermined width and uniform depth is formed over the entire bottom surface of the recess.

<Embodiment> Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a semi-open induction hardening coil for hardening the surface of a crankshaft bottle. 1 to 5 are drawings for explaining one embodiment of the present invention, in which FIG. 1(a) is a perspective view, and FIG. Cross-sectional view indicated by line arrows, Figure 2 (a) is a perspective view (excluding core), Figure 2 (c)
are a sectional view taken along the line A-A in FIG. 2(a), FIG. 3(a),
(b) is a front view and a plan view with the core removed, respectively, and FIGS. 4(a) and (b) are a sectional view taken along the line A-A in FIG. FIG. 5 is a side view showing a semi-open induction hardening coil disposed close to the bottom of the recess of the workpiece. Components equivalent to those described in the related art will be described with the same reference numerals.

The semi-open induction hardening coil 50 of this embodiment is disposed close to the surface 11 of the crankshaft pin 10, as shown in FIGS. 4 and 5, and is used to harden this surface 11. used. This semi-open induction hardened coil 50 is
As shown in FIGS. 1 and 2, the heating coil 51 (
(first heating coil), heating coil 52 (second heating coil), connection coil 53, feeding coil 54, feeding coil 5
5 and a core 59. All of these coils are made of hollow, highly conductive metal.

The heating coil 51 is formed into an approximately 1/4 arc shape to correspond to the shape of the surface 11, and the heating coil 52 is formed into approximately the same shape as the heating coil 51 (however, the heating coil 52 is formed into an approximately 1/4 arc shape to correspond to the shape of the surface 11). It is not limited to 4, and an appropriate value can be selected depending on the required depth of the hardened layer, etc.). As shown in FIG. 2, one end 511.521 of the heating coil 51.52 is connected by a connecting coil 53. Heating coil 51.52 other end 512.522
have one end 541 . of the feeding coil 54 , 55 , respectively.
551 are connected, and the other ends 542 and 552 are formed so as to be close to each other, and these other ends 542
．． 552, as shown in FIG. 1, each coil cooling liquid supply pipe 41. A discharge pipe 42 is connected. Moreover, the high frequency power source 40 is connected between these other ends 542 and 552.

The heating coils 51, 52 and the connecting coil 53 are made of a core 59 made of ferrite or N steel plate and having a roughly L-shaped cross section, as shown in FIG. 1(b) using the example of the heating coil 51.
1.592, except for the surface 513 facing the surface 11, and the heating coil 51 is sandwiched from both sides by the bonded cores 591 and 592. Hollow portions 51a and 54a of the heating coil 51 and the feeding coil 54, respectively, serve as passages for the cooling fluid of the semi-open induction hardening coil 50. The same applies to the hollow portions of the heating coil 52 and the feeding coil 55.

In addition, as shown in FIGS. 3(a) and 3(b), spacers 61, 62, 63, and 64 are provided in a manner not shown in order to maintain a predetermined distance between the semi-open induction hardening coil 50 and the workpiece 10. It is attached near the connection coil 53.

Although not shown, a cooling liquid jacket is separately provided for injecting a cooling liquid for hardening onto the surface 11 of the pin 10 heated by the semi-open induction hardening coil 50.

Next, the operation of this embodiment will be explained.

The crankshaft is rotated and the semi-open induction hardening coil 50 is arranged such that the heating coils 51,52 are close to and opposite the surface 11 of the pin 10.

The cooling liquid of the semi-open induction hardening coil 50 is supplied to the supply pipe 41, passes through the power supply coil 54, heating coil 51, connection coil 53, heating coil 52, and power supply coil 55 to cool these coils, and then passes through the discharge pipe. It is discharged from 42. The high frequency current generated by the high frequency power supply 40 is transmitted to the feeding coil 54.
, returns to the high frequency power source 40 via the heating coil 5L connection coil 53, heating coil 52 and power feeding coil 55.

One side of the surface 11 of the pin IO is heated by an induced current induced by a high frequency current flowing through the heating coil 51, and the other side of the surface 11 is heated by an induced current caused by the heating coil 52, and the surface 11 is heated by an induced current caused by the heating coil 52. The central part of the surface 11 is heated by the induced current generated by the connecting coil 53.
A width of approximately 10 mm is uniformly heated. Therefore, the length of the heating coils 51, 52, the interval between the heating coils 51, 52 (the length of the connecting coil 53), the magnitude of the high frequency current,
By appropriately selecting the energization time, Fig. 4(a)
As shown in , i), about 10 mm on the surface 11 of the pin 10.
It is possible to form a hardening N13 having a uniform depth and having a width from front to back.

In addition, in the heating coils 51 and 52 of this embodiment, the portion where the high frequency current is concentrated, that is, the portion facing the surface 11 of the pin 10, directly contacts the cooling liquid and the temperature rise is low, so that the temperature rise is lower than that of the conventional half. The degree of oxidation is smaller than that of the open induction hardened heating coil, so it is possible to prevent the occurrence of cracks caused by a decrease in mechanical strength due to the progress of oxidation.

<Effects of the Invention> As explained above, in the semi-open induction hardening coil of the present invention, one side of the annular surface formed on the circumferential surface of the workpiece is heated by the first heating coil, and the other side is heated by the second heating coil. Since the center portion of the heating coil is heated by the connection coil that connects the first and second heating coils, it is possible to form a hardened layer with a uniform depth over the entire annular surface.

[Brief explanation of drawings]

1 to 5 are drawings for explaining one embodiment of the present invention, in which FIG. 1(a) is a perspective view, and FIG. 1(b) is an A--A in FIG. 1(a). A sectional view indicated by line A, Fig. 2(a) is a perspective view (excluding the core), Fig. 2(b) is AA of Fig. 2(a)
3(a) and (b) are respectively a front view and a plan view excluding the core, and FIGS. 4(a) and (b) are sectional views taken along the line 1-A in FIG. The cross-sectional view, the cross-sectional view taken along the line B--B, and FIG. 5 are explanatory side views in a state where the semi-open induction hardening coil is disposed close to the surface of the pin of the crankshaft. Figure 6 is a perspective view of a conventional semi-open induction hardening coil (excluding the core), and Figure 7 is a vertical cross-sectional view of a crankshaft pin and the semi-open induction hardening coil in a state of heating a workpiece. 6 is a sectional view taken along the line A-A in FIG. 6, and FIG. 8 is a side view of the pin. 10...Pin, 11...Surface, 40...High frequency power supply, 50...Semi-open induction hardening coil, 5152...
・Heating coil, 53... Connection coil, 54.55...
・Feeding coil, 59...core.

Claims (1)

[Claims] (1) Approximately 1/4 circular or
a first heating coil having an arcuate shape with a circle smaller than /4 circle; and a second heating coil disposed close to the surface to be hardened on the other side and having approximately the same shape as the first heating coil. , a connecting coil disposed close to the surface to be hardened and connecting one ends of the first and second heating coils; and one end connected to both ends of the first and second heating coils and the other end thereof. a pair of feeding coils formed so as to be close to each other; and a core formed so as to cover a surface of the first and second heating coils and a connecting coil that does not face the surface to be hardened. A semi-open induction hardened coil, characterized in that a high frequency voltage is applied between the other ends of the power feeding coil.