JPS61237387A - Resistance type heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resistance heating device, and more particularly to a resistance heating device for brazing the tip blade of a circular saw to an alloy.

(Prior Art) Generally, when brazing the chip blade of a circular saw to an alloy, as shown in FIG. Electrodes 4.5 are brought into contact with the chip blade 3 and the vicinity of the chip blade 3 of the base metal 1, and a current is passed between the blade base 2 and the chip blade 3 through these electrodes to heat them both, so that both of them reach a predetermined temperature. After applying an antioxidant to both abutting surfaces 2a and 3a at the stage where they are heated to
Silver solder is melted and supplied to parts a and 3a to fix them together.

In this case, as shown in FIG. 2, in the conventional heating device, when the switch is turned on at point a, the tip blade 3, which is the object to be heated,
and the standard amount of electricity C1 to the second part of the blade, for example 5v, 300
A was immediately energized, and when the switch was turned off at point b, the energization was immediately cut off.

Therefore, when the switch is turned on, that is, when electricity starts flowing, a large amount of current instantly flows through the heated object, and the heating rate of the heated object becomes rapid like the d line, and when the electricity is cut off, the cooling rate is e. It becomes rapid like a line.

(Problem to be solved by the invention) If the amount of energization at the start of one energization increases instantaneously in this way,
A contact surface 3a between the chip blade 3 and the blade base 2.

2a becomes short-circuited, and the corresponding contact surface 3a.

Sputtering occurs in the portion 2a, resulting in a spotty oxide film. Then, silver solder no longer adheres to the oxide film portion, and the adhesion force between the tip blade 3 and the blade base 2 decreases.

Further, the chip blade 3 is susceptible to thermal distortion, and if it is rapidly heated or cooled, the thermal distortion becomes large and it becomes easily damaged.

The present invention has been made in view of the above-mentioned circumstances, and by suppressing the sudden energization and heating of the heated object at the start of energization, the heated object can be smoothly soldered, and the heated object can be prevented from being heated due to thermal distortion. The object is to obtain a resistance heating device that can prevent damage.

(Means for Solving the Problems) In order to solve the above objects, the present invention is characterized by having the following configuration.

That is, a load circuit that inputs a signal and energizes the heated objects to be joined together, an output circuit that outputs a signal to the load circuit, and a signal generation circuit that controls the output signal of the output circuit are provided, and the signal generation The circuit is configured to include a start adjustment circuit that adjusts the rate of increase in the amount of signal generation at the start of energization.

(Function) Since the present invention has the above configuration, if the start adjustment circuit is set to a predetermined value, the signal generation circuit can increase the amount of signal generated at the start of energization with a predetermined characteristic according to the elapsed time. become.

As a result, the signal output from the output circuit to the load circuit is controlled, and the amount of current flowing through the load circuit and, therefore, the amount of current flowing through the heated body increases at a predetermined rate over time.

(Example) Hereinafter, an example of the present invention will be described based on the block diagram shown in FIG.

In the figure, 10 is changed from 10Ov to 5V by a transformer, for example.
This is an AC power supply whose voltage is stepped down to V, and a load circuit 11 is connected to this AC power supply 10.

In the load circuit 11, an electrode connected to a heated object and a triac are connected in series to the AC power source 10.

12 is an output circuit that controls the phase angle of the triac provided in the load circuit 11, and includes an oscillator; a reference value setting circuit that adjusts the signal from the oscillator by the gelium 13a of the triac; 14, the output circuit 12; This signal generation circuit 14 controls the output signal of the signal generation circuit 14.
The start adjustment circuit 15 has a start adjustment circuit 15 in which the increase rate of the signal generation amount is adjusted by the start setting volume 15a when the switch is turned on, that is, at the start of energization, and the attenuation rate of the signal is adjusted by the attenuation setting when the switch is turned off, that is, at the end of energization. The attenuation adjustment circuit 16 is adjusted by a volume 16'a.

In FIG. 1, 17 is the object to be heated, 18 is a buzzer circuit that notifies that the heating of the object to be heated 17 is completed, and a timer circuit that operates by inputting a signal from the signal generation circuit 14 and the timer. Consists of a buzzer activated by

Next, the operation of the above embodiment will be explained.

First, by operating the output setting volume 13a, the maximum output of the output circuit 12 is set by the reference value setting circuit 13, and thereby the maximum output of the output circuit 12, which is the object to be heated 17, is The maximum output will be set.

Next, by operating the start setting volume 15a, the start adjustment circuit 15 sets the increase rate of the signal generation amount at the start of energization of the signal generation circuit 14 as shown in line f in FIG. contact surface 2a,
The short-circuit condition at 3a is eliminated, and as a result, the heating rate suitable for the hardness or material of the chip blade 3 is set to g in the same figure.
It becomes gradual as shown by the line.

In addition, by operating the attenuation setting volume 16a, the attenuation adjustment circuit 16 sets the attenuation rate of the signal at the final stage of energization of the signal generation circuit 14 as shown in the second grid line. The cooling rate suitable for this is slow as shown by line j in Figure 2.

Then, when the load circuit 11 finishes energizing the heated object 17 and a predetermined period of time has elapsed, the buzzer circuit 18 is activated and a termination buzzer sounds.

(Effects) As explained above, according to the present invention, the rate of increase in the amount of energization at the initial stage of energization is adjusted to suit the object to be heated, and therefore the object to be heated is heated by adapting it to the size or material of the object. It is possible to obtain a heating device whose speed can be adjusted and which is particularly suitable for brazing the chip blade of a circular saw to the base metal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a characteristic diagram showing current and heating temperature versus time, and FIG. 3 is a side view showing a soldered state of a chip blade of a circular saw. 1: Base metal, 2: Blade base, 3: Chip blade, 4: Electrode. 10: AC power supply, 11: Load circuit, 12: Output circuit, 1
3: Reference value setting circuit, 13a: Output setting volume, 1
4: Signal generation circuit, 15 nister adjustment circuit, 15a;
Start setting volume, 16: Attenuation adjustment circuit, 16a
: Attenuation setting volume, 17: Heated object, 18: Buzzer circuit. Application agent Hisashi Matsumoto Figure 2 a b Time → Figure 3 Retsu Jζ

Claims (1)

[Claims] 1. A load circuit that inputs a signal and energizes the heated objects to be joined together, and an output circuit that outputs a signal to the load circuit;
and a signal generation circuit that controls the output signal of the output circuit,
A resistance heating device characterized in that the signal generation circuit is provided with a start adjustment circuit that adjusts the increase rate of the signal generation amount at the time of starting energization.