JPS5828333B2 - Induction heating/quenching method and device for annular bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to induction heating of an annular portion of an annular body to be hardened, a hardening method, and an apparatus.

More specifically, when the annular part of the annular body to be quenched is quenched by relative rotation between the annular body and the induction heating coil, no quenching remains between the heating start part and the quenching end part. The present invention relates to a method and apparatus for reducing the joint portion where no hardened layer is formed as much as possible, and greatly improving the heat treatment speed.

Conventionally, in order to harden the ring-shaped surface to be hardened of a ring-shaped member such as a large pole race, one induction heating coil is held at a predetermined gap with a certain part of the ring-shaped surface to be hardened. After arranging the induction heating coil and turning on the power to the induction heating coil, fix either the induction heating coil or the ring-shaped member.
This method uses an induction heating coil to sequentially and continuously inductively heat and harden the ring-shaped surface to be hardened, with the other rotating.

However, in such a ring moving hardening method, after the induction heating coil starts heating, once the ring-shaped surface to be hardened has finished hardening, the induction heating coil circulates back to the heating starting point. Because of the structure, when the power is turned on until the heating start point and the induction heating coil returns to circulation, the part near the heating start point that has already been quenched and has a hardened layer will return to circulation. There is a risk of quenching cracking due to the heat of the induction heating coil, or it may become softened and become a weak point in terms of strength.

In order to deal with this, conventional methods have taken the approach of stopping the current supply to the induction heating coil far before the heating start point, at a distance where the hardened layer is not affected by the heating effect of the magnetic flux from the heating coil.

However, in this method, since the area between the heating start point and the heating end point is not hardened, there is a wide area where the hardened layer is not formed, which also becomes a weak point in terms of strength.

Nowadays, the parts to be hardened have become larger, and as a result, hardening has come to be performed at high speed with relatively large heating coils using relatively high power, and the wide width of this unhardened part has become a problem that cannot be ignored. It started to get a close-up.

The present invention has been made in order to solve the above-mentioned problems that exist in this type of induction heating method.

The present invention will be explained according to the embodiments shown in FIGS. 1a-4 to 2-2.

In FIGS. 1a to 2, reference numeral 1 indicates a rotating body such as a turntable, and a rotating shaft 5 that rotates by driving a power source 6 is attached to the center of the rotating body 1. As shown in FIGS.

Reference numeral 2 denotes an annular body to be hardened, which is placed concentrically on the rotating body 1.

3 and 4 are heating coils, heating coil 3 is a large heating coil that is elongated in the advancing direction with high heating power, heating coil 4
is a small heating coil that is shorter and smaller in the traveling direction and has a smaller heating power than the heating coil 3.

The large heating coil 3 is arranged ahead of the small heating coil 4 in the quenching progress direction, but adjacent to both.

A plurality of coolant injection holes 4 are provided on the rear lower surface of the small heating coil 4.
3 is provided to be inclined in the rearward direction, and the cooling liquid from a cooling liquid supply source (not shown) passes through the cooling liquid supply pipe 42 and the cooling liquid passage 41 in the small heating coil 4, and is sequentially applied to the heated surface. Spray continuously.

In such a configuration, while turning on the power sources E and E' of the large heating coil 3 and the small heating coil 4,
Drives the power source 6.

The rotating shaft 5 rotates at a predetermined speed by driving the power source 6,
The rotating body 1 is rotated about the rotating shaft 5, for example, in the direction of the arrow in FIG. 1a.

As a result, the surface of the annular body 2 to be hardened is heated by the large heating coil 3 and the small heating coil 4 as the rotating body 1 rotates, and then the cooling liquid provided on the rear lower surface of the small heating coil 4 is heated. The cooling liquid injected from the injection holes 43 sequentially hardens the material.

When most of the annular surface of the annular body 2 to be quenched has been hardened, the large heating coil 3 and the small heating coil 4 are
For example, in the position shown in FIG. 1a.

Note that the line indicated by a is the heating start point.

When the quenching progresses further and the tip of the large heating coil 3 reaches a position close enough to the heating effect due to the magnetic flux just before the heating start point a, this is detected by a known detection mechanism, In response to the detection signal from the detection mechanism, the power supply E of the large heating coil 3 is cut off, and the rotational speed of the rotating shaft 5 is gradually reduced using a known transmission mechanism.

Of course, the reduced rotational speed in this case is determined by the ratio between the power input to the large heating coil 3 and the power input to the small heating coil 4.

After that, hardening is performed using the small heating coil 4 while the rotational speed of the turntable 1 is reduced, and when the small heating coil 4 reaches just before the heating start point, it is detected by a known detection mechanism, In response to the detection signal from the detection mechanism, the power source E/ of the small heating coil 4 is cut off, and the power source of the turntable 1 is also cut off to stop its rotation.

In this case, since the electric power of the small heating coil is lower and the length is shorter than that of the large heating coil, it is possible to approach the heating start point a much closer than the large heating coil.

A detection mechanism generates a signal to turn off the power E of the large heating coil 3 and reduce the rotational speed of the turntable 1, and a detection mechanism generates a signal to turn off the power E' of the small heating coil 4 and stop the rotation of the turntable 1. As a detection mechanism for generating the signal, for example, a signal current opening/closing contact may be attached to the side of the front end of a large heating coil or a small heating coil, and the signal current may be operated by a contact placed on the quenching start line.

In the above actual case, the annular body to be hardened was placed on a turntable and rotated, and the induction heating coil was fixed, but the annular body to be hardened was fixed and the induction heating coil was fixed. The same effect as above can be achieved by rotation.

Furthermore, in the actual case mentioned above, an example is mentioned in which the power supply E of the large heating coil 3 is cut off when the large heating coil 3 reaches just before the heating start point, but instead of that, the large heating coil 3 is , the large heating coil 3 may be displaced upward or sideways from the fixed heating position while continuing to be energized.
This is easily possible by connecting it to a displacement mechanism that displaces it upward or sideways.

In this case, instead of using separate power sources to supply power to the large heating coil and small heating coil as shown in Figures 1a to 2a, the large heating coil and small heating coil are connected in series. Both may be supplied with power from a single power supply.

Similarly, a displacement mechanism may be added to the small heating coil 4 so that it is displaced upward or sideways instead of turning off the power source E' at the end of hardening.

In the above embodiment, the annular hardened surface is a flat end surface, and therefore the shape of the heating coil is also a so-called end surface hardened type, but the present invention is also applicable when the annular hardened surface is the outer peripheral surface, inner peripheral surface, or the entire surface surface. Moreover, even if it is a concave groove or a convex part,
Naturally, the present invention is also applicable to those using heating coils depending on the shape of the heating coil.

According to the present invention, until the large heating coil makes one revolution from the heating start point and returns to circulation, most parts of the annular surface are heated at high speed by the two heating coils, the large heating coil 3 and the small heating coil 4. Since it is configured to heat and harden continuously, efficient hardening is possible, and after that, small parts are heated only by the small heating coil 4 at a reduced relative rotation speed. , because it is hardened, it is easy to adjust the width of the joint near the heating start point to be extremely small compared to the conventional one, and the degree of relative rotational speed reduction can be reduced by the heating power of the small heating coil 4, the large From the relationship between the heating power of the heating coil 3 and the rotational speed before deceleration, it is set to give the same heating effect to the annular body surface as before deceleration, so the annular surface other than the slightly remaining seam is heated. A uniform hardened layer can be efficiently formed.

It goes without saying that the present invention is applicable not only to surface quenching of the upper surface, inner surface, or outer surface of an annular body, but also to whole quenching (sub-hardening) of the annular body.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing an embodiment of the present invention, FIG. 1A is a front view of FIG. 1A, and FIG. An enlarged perspective view showing a small heating coil, Figure 2 and Figure 2a
FIG. 2 is a sectional view taken along line 2b-2b of FIG. 1... Turntable, 2... Annular body, 3... Large induction heating coil, 4...
Small induction heating coil, 43... Cooling exhaust injection hole for quenching, E, E'... Power source for induction heating coil, a
・・・・・・Heating start point.

Claims (1)

[Claims] 1. Due to the relative rotation between the annular body and the induction heating coil,
When hardening the annular part of the annular body to be hardened,
As an induction heating coil, it is equipped with a large heating coil that is elongated in the direction of propagation of the heating power, and a cooling liquid injection hole for quenching that is provided adjacent to the rear of the coil in the direction of propagation.
In addition, by using a small heating coil that is shorter and smaller in the advancing direction with less heating power than the large heating coil, power is supplied to both the large heating coil and the small heating coil at the same time, and the annular body and the induction heating coil are connected. Heating and quenching by relative rotation is started, and immediately before the large heating coil circulates back to the heating start point of the annular body, the magnetic flux exerting a heating effect by the large heating coil is cut off from the heated annular body, A method for induction heating and quenching an annular body, characterized in that the relative rotational speed is reduced so that from that point on, only the small induction heating coil performs heating and quenching up to the heating start point. 2. The induction heating and quenching method for an annular body according to claim 1, wherein the power to the large heating coil is cut off immediately before the large heating coil circulates back to the heating start point of the annular body. 3. Induction heating and quenching of an annular body according to claim 1, wherein the large heating coil is displaced and removed from the fixed heating position immediately before the large heating coil circulates back to the heating start point of the annular body. Method. 4 The induction heating coil is fixed, the annular body is placed on a rotating body such as a turntable, and the annular part of the annular body is induction heated and quenched with the induction heating coil by rotation of the turntable. The induction heating and quenching method for an annular body according to item 2 or 3. 5. Induction heating of an annular body according to claim 1, 2, or 3, in which the annular body is fixed and the induction heating coil is rotatable along the annular part to be hardened of the annular body, Quenching method. 6 Due to the relative rotation between the annular body and the induction heating coil,
When heating and quenching the annular part of the annular body to be quenched, a large heating coil that is elongated in the direction of propagation of the heating power, and a cooling device for quenching that is provided adjacently to the rear of the quenching coil in the direction of propagation. A small heating coil that is shorter in the direction of travel and equipped with a liquid injection hole and has a lower heating power than the large heating coil, and after heating and quenching start, the large heating coil approaches the heating start point of the annular body. and a detection mechanism for detecting the return of circulation to the position, and a detection signal from the detection mechanism turns off the power to the large heating coil and reduces the relative rotational speed in a predetermined manner. Body induction heating and quenching equipment. γ Due to the relative rotation between the annular body and the induction heating coil,
When heating and quenching the annular part of the annular body to be quenched, there is a large heating coil that is elongated in the direction of travel, which is the source of the heating power, and a cooling device for quenching that is installed adjacent to the rear of the coil in the direction of travel. A small heating coil that is equipped with a liquid injection hole and is shorter in the advancing direction and requires less heating power than the large heating coil, and after heating starts, the large heating coil is circulated back to a position close to the heating start point of the annular body. and a displacement mechanism that displaces the dog-shaped heating coil from its fixed heating position in response to a detection signal from the detection mechanism. An apparatus for induction heating and quenching of annular bodies, which is designed to reduce the moving speed. 8. Claim 6 or 8, in which the annular body is placed on a rotating body such as a turntable, the induction heating coil is fixed, and the rotational speed of the turntable etc. is reduced by a detection signal from a detection mechanism. The induction heating and quenching device for an annular body according to item 7. 9 A patent in which an annular body is fixed, an induction heating coil is configured to be rotatable along the annular part of the annular body to be hardened, and the rotation speed of the induction heating coil is reduced by a detection signal from a detection mechanism. An apparatus for induction heating and hardening of an annular body according to claim 6 or 7.