JPS589550B2 - induction heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION For example, the present invention can transport a metal bar material continuously by a transport device consisting of a vinyl roller, a guide roller, etc.
This invention relates to an induction heating device (generally called a bar heater) for a so-called hot former that heats the metal bar material by the electromagnetic induction action of a plurality of heating inductor coils, and also hot cuts and forges the metal bar material. In particular, when the hot homer breaks down, the bar material inside the inductor coil is discharged, a new bar material is supplied, and the heating power is supplied, and the metal bar material is kept inside the inductor coil until the hot homer malfunction is repaired. The heating temperature is kept constant while moving back and forth, and when the hot homer is repaired,
The purpose is to provide an induction heating device that allows cutting and forging operations to be performed immediately without waiting.

FIG. 1 shows an embodiment of the present invention, in which 1 is a metal bar material to be processed, 2-1.2-2...w2-N are spaced apart from each other at a predetermined interval on the conveyance path of the metal bar material 1. A plurality of heating inductor coils arranged, R is a conveyance device that conveys the metal bar material 1 in a predetermined direction at a predetermined speed, and this conveyance device R includes a pinch roller 3 of an induction heating device and a pinch roller of a hot former. 4, a guide roller 7, and a feeder roller 8.

5 is a supply device for the metal bar material 1, 6 is a discharge device for the metal bar material 1 when the hot former breaks down, 9-1.9-2...
-9-N is a heating power source with a predetermined frequency connected to each of the heating inductor coils 2-1, 2-2,...2-N, and this heating power source includes a delay compensation power factor capacitor and a voltage adjustment capacitor. A matching transformer is included.

Reference numeral 10 denotes a cutter for hot cutting the metal bar material 1 into a predetermined length, and a forging device (not shown) is disposed beside the cutter 10.

Since the induction heating apparatus of the present invention is constructed as described above, the metal bar material 1 is supplied from the supply device 5 to the feeder roller 8, and then passed through the pinch roller 3 and then sequentially transferred to the inductor coil by the idle roller 7. The material is heated while passing through 2-1 to 2-N, and is cut into a predetermined length by the cutter 10 of the hot former. It is forged into a predetermined shape.

Figure 2 shows the temperature distribution in each part of the metal bar material 1 while being continuously conveyed in the manner described above. rF
It is shown by the OJ curve.

Strictly speaking, the gap length r between the heating inductor coils
At LaJ, since the metal bar material 1 is not heated, the temperature slightly decreases, and the curve rFOJ is not a straight line as shown in the figure, but a stepped curve.

Next, if a failure occurs in the hot former during the above-mentioned process, in the conventional induction heating equipment, the conveyance is stopped and the heating power source is turned off to turn the metal bar material at the time of failure into rOF.
Even with FJ or ON-OFFJ control, the distance from the exit end of the final stage inductor coil to the cutter (corresponds to L1 in Figure 1)
And the temperature drop between the inductor coils (corresponding to L2 in Figure 1) increases. Since the temperature unevenness in the longitudinal direction of the metal bar material becomes large and has a negative effect on the cutter, all the metal bar material 1 being transported is moved back in the opposite direction and stored in the discharge device 6. After repairing the hot homer, install new metal bar material 1.
is supplied from the supply device 5 to the feeder roller 8 again to start the predetermined work process. However, with this method, after the hot former is repaired, it takes some time (diameter 60m/m metal bar material 1
, it takes about 3 minutes to heat up to 250°C), which deteriorates operating efficiency.

This invention was made with attention to this point, and when the hot homer breaks down, the bar material in the inductor coil is discharged, a new bar material is supplied, and the hot homer is sent while the heating power is being supplied. Until the repair is completed, a new metal bar material is installed inside the inductor coil in order to eliminate the temperature drop in the gap between the inductor coils (corresponding to La in Figure 1), that is, the temperature unevenness in the longitudinal direction of the metal bar material. The object of the present invention is to provide an induction heating device that maintains a constant heating temperature while reciprocating and allows cutting and forging operations to be performed immediately upon completion of repair of a hot former.

Next, a specific example of the working process according to the present invention will be explained.
/mm), and the power applied to the inductor coil is P1n(K
W) (where n=1 to N).

When the hot former malfunctions, the metal bar material 1 in the inductor coil is moved back in the opposite direction to be stocked at the discharge charge 6, and a new metal bar material 1 is supplied from the supply device 5 to the feed roller 8 and heated. When the tip of the metal bar material 1 reaches the exit point -1 of the final stage inductor coil 2-H while power is being supplied, the power source is turned to rOFFJ to stop the forward feeding of the metal bar material, and this time, Conversely, the metal bar is moved backward at a backward speed v2 (m/mm) until the tip of the metal bar reaches point ■.

In this way, when the tip of the metal bar reaches the tip point, the metal bar is again fed forward at the forward speed V3 (m/mm), the power is turned on, and the inductor coil 2 is turned on.
-N is P2n (KW) (where n=1 to N
and Of,02).

Then, when the tip of the metal bar material reaches the point (2) again, the power source is turned to rOFFJ, and the metal bar material is moved backward at a backward speed of (2) (m/am).

The forward speed V3 of the metal bar material mentioned above is approximately 1/2 to 1/3 of the forward speed ■1 during normal continuous feeding, and the power P2n applied to the inductor coil is set at the tip of the metal bar material 1. The power needs to be such that when the temperature distribution reaches the point (■) from the Horsho point, the temperature will be the same as the temperature distribution during normal continuous operation.

For this purpose, it is necessary to supply different electric power to each inductor coil 2-1 to 2-H.

This is because the temperature of each metal bar material corresponding to each inductor coil 2-1 to 2-H is different, so the temperature drop is inevitably different due to heat dissipation, and because each metal bar material is heated. This is because the ratio of electric power (heating efficiency) differs depending on each temperature range.

For the above reasons, it is desirable that each of the heating power sources 9-1 to 9-N connected to each inductor coil 2-1 to 2-N can independently adjust the power θS.

However, since it is extremely uneconomical to connect independent heating power sources to each of the inductor coils 2-1 to 2-N, a matching transformer is provided for each inductor coil to adjust the tap voltage. Alternatively, by adjusting the windings of each inductor coil, a single heating power source may be used to apply power to each inductor coil.3Also, as described above, the forward speed V3 of the metal bar material ( m/mm) is 1/2 of the forward speed V1 (m/mm) during normal continuous feeding.
The reason for selecting approximately 1/3 is that by raising the temperature over a relatively long period of time, the gradient of the temperature increase can be made gentler, making it easier to maintain a temperature close to the predetermined temperature.

According to the procedure described above, when the hot homer breaks down, the metal bar material 1 in the inductor coil is discharged, a new metal bar material 1 is supplied, and the feeding metal bar material 1 is transferred to the final stage while the heating power is supplied. Inside the inductor coil 2-N, that is, its tip moves back and forth between points ■ and ■ to eliminate temperature unevenness in the longitudinal force direction of the metal bar material and maintain it at a constant temperature, and when the hot homer failure is repaired. , switched to normal operation.

However, if the metal bar material is in the middle of a reciprocating motion, it is switched when its tip reaches point (■).

In this way, after the repair of the hot printer is completed, the time it takes to cut it with a cutter, which previously took about 3 minutes, can be shortened to just a few seconds.

According to this invention, as described above, when a hot homer breaks down, the heating temperature is kept constant while the metal bar is moved back and forth within the inductor coil until the fault is repaired, and the hot homer is repaired. When the process is completed, the cutting and forging work can be carried out immediately without waiting for a certain amount of time, which has the excellent effect of providing an induction heating device with extremely high operating efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing an embodiment of the present invention, and FIG. 2 is a temperature distribution diagram of a metal bar material. In the drawing, 1 is a metal bar material, 2-1 to 2-N are inductor coils, ■ is a conveying device, 4 is a hot former pinch roller,
Guide rollers 59-1 to 9-N are heating power sources, and 10 is a cutter of a hot former.

Claims (1)

[Claims] 1. A conveying device that continuously conveys a plurality of metal bar materials;
A plurality of heating inductor coils are arranged at predetermined intervals on the conveyance path of this conveyance device, and a hot former is used to cut the metal bar material heated by the inductor coils into a predetermined length and forge it. In case of a malfunction in the hot homer, the bar material in the inductor coil is discharged, a new bar material is supplied, and the hot homer is fed with heating power supplied and kept in the final stage inductor coil until the hot homer is repaired. An induction heating device comprising means for maintaining a constant heating temperature while reciprocating a metal bar material. 2. The induction heating charge according to claim 1, wherein the reciprocating movement of the metal bar material is performed by a pinch roller and a guide roller of an induction heating device. 3 To maintain the temperature of the metal bar material, the final stage inductor coil O
The induction heating device according to claim 1, characterized in that the heating is performed by N-OFF.