JPS6164293A - Clothing dryer - 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] Industrial applications The present invention relates to a tram-type clothes dryer.

Conventional F14 construction and its problems Clothes dryers rely on some kind of heat source to obtain hot air. In recent years, semiconductor ceramic heaters with a positive temperature coefficient of resistance have come into widespread use for safety reasons, and even if the heater is energized when air is not being blown due to some kind of malfunction, the amount of heat generated is kept to a minimum. Care has been taken to keep it at a minimum. However, even with such a heater, the power consumption is about one-tenth of the rated operating power, so there is little chance of a fire due to a sudden temperature rise, but if this condition continues for a long time, the drum If the clothes stored inside the container are scorched or the conditions are poor, there is a possibility that a fire may occur.

OBJECTS OF THE INVENTION In order to eliminate such risks, the present invention provides a highly safe clothes dryer with appropriate protective functions.

The structure of the present invention is 11f which controls the energization to the heater and the motor.
F1゛η consists of the i'1fu control (incorporated) device, a current detection device that monitors the energization status to the heater, and a control section that receives the output of this current detection device and controls the operation of the energization control device. Ru. The control fa 1 section performs the following protective operation if the current flowing through the heater detected by the power IN and exposure device 4 shows a value different from that when the energization control device is operating normally. That is, the power supply to all electric circuits related to power supply to the heater is stopped, the abnormal state is notified to the user, or these protective operations are performed simultaneously.

DESCRIPTION OF EMBODIMENTS Next, embodiments of the present invention will be described. FIG. 1 shows an electrical circuit diagram of this embodiment. 1 is a control section, 2.3 is an energization control device, 4 is a DC detection device, 6 is a motor, a six-piece semiconductor ceramic heater (hereinafter referred to as a heater). The heater 6 is a heat source for obtaining hot air, and the motor 5 is used to drive a fan to send hot air into the drum through the heater 6 and to rotate the drum using a power transmission means such as a belt. It is a power source. Energized; I? In this embodiment, the lJ control device 2゜3 is constituted by a bidirectional switching element, and the energization control device 2 controls the energization to the motor 5 in response to a signal from the control section 1, and the energization control device 2 controls the energization to 1ttl.
l ii'['l The device 3 similarly receives the signal from the utility section 1 and controls the energization to the heater 6. In this embodiment, the radio wave production device 4 is constituted by a current transformer, and monitors the energization status of the heater 6 and transmits the status to the control unit 1. 7 is an outlet, and 8 is a power switch.

Next, control (2) part 1 will be described. Reference numeral 9 denotes a power supply circuit that converts the commercial alternating current supplied from the outlet 7 into positive and negative direct current power for the control circuit. The zero output terminal of the power supply circuit 9 is connected to the ground of the sterilization circuit (hereinafter simply referred to as ground), and the positive output terminal is connected to one line on the commercial AC side and the positive terminal of the microcomputer 10 and other circuit parts. Connected to the power supply terminal. A negative output terminal of the power supply circuit 9 is connected to a negative power supply terminal of the operational amplifier 11. 1
2 is a voltage comparator, 13 to 16 are transistors, 17°1
8 is a diode, 19 to 27 are resistors, 28 and 29 are capacitors, 31 is a buzzer, and 30 is a relay. relay 3
The coil 0 is connected between the positive output terminal of the power supply circuit 9 and the collector of the transistor 13, and the resistor 19 is connected between the output terminal (A) of the microcomputer 1Q and the base of the transistor 13. The emitter of transistor 13 is connected to ground. The contacts of the relay 30 are closed when the coil is not energized, and when it receives a high-level signal from the output terminal (A) of the microcomputer 1Q, the transistor 13 becomes energized and current flows through the coil of the relay 30. flows and opens the contact. The diode 18 has its cathode connected to the positive output terminal of the power supply circuit 9 and its anode connected to the collector of the transistor 13, and is used as an IF to prevent destruction of the transistor 13 due to a back electromotive force when the coil current of the relay 30 is cut off.

The terminal (=) of the microphone a/computer 10 is an output terminal, and is connected to the base of the transistor 14 via a resistor 20. The emitter of the transistor 14 is connected to ground, and the collector is connected to a control input terminal of the energization control device 2 via a resistor 21. When the output terminal (b) outputs a high level signal, the transistor 14 becomes conductive, and the energization control device 2
A current flows out from the control input terminal of the motor 5, which becomes conductive, and the motor 5 operates.

Similarly, the terminal (c) of the microcomputer 10 controls the operation of the heater 6 in combination with the resistors 22 and 23, the transistor 15, and the energization control device 3.

terminal) is an output terminal, which is connected to the pace of the transistor 16 via a resistor 24. A buzzer 31 is connected between the positive output terminal of the power supply circuit 9 and the collector of the transistor 16, and the emitter of the transistor 16 is connected to ground. ) outputs a high level signal to the output terminal, the transistor 16 becomes conductive and causes the buzzer 31 to sound.

The terminal ←) is an input terminal, and the current state of the current to the heater 6 is inputted thereto. A resistor 27 (rll is used as a load resistor for current detection, is connected to both ends of its output terminal, and is connected between the positive input terminal of the operational amplifier 11 and ground. The capacitor 28 is connected to the resistor 27 and Connect in parallel, N
Used to prevent malfunctions caused by r-sounds. The anode of the diode 17 is connected to the output terminal of the operational amplifier 11, and the cathode is fed back and connected to the negative input terminal of the operational amplifier 11. Resistor 26 and capacitor 29
are connected in parallel between the cathode of diode 17 and ground. The current detection device 4 generates an alternating current voltage across the resistor 27 by electromagnetic induction in proportion to the magnitude of the current flowing through the heater 6. This alternating current voltage is rectified by a rectifying circuit made up of an operational amplifier 11 and a diode 17, smoothed by a smoothing circuit made up of a resistor 26 and a capacitor 29, and appears as a converted direct current voltage at point A in Figure 1. .

FIG. 2 shows the relationship between the current flowing through the heater 6 and the potential at point A. As shown in the figure, the potential at point A increases in proportion to the current flowing through the heater 6.

This potential signal at point A is input to the non-inverting input terminal of the voltage comparator 12 as shown in FIG. 32 is a D/A converter, which is an output port of the microcomputer 10 (to)
The data signal of is converted to voltage, and the output terminal is connected to heavy pressure comparator 1.
20 is connected to the inverting input terminal. The resistor 25 is connected between the output terminal of the voltage comparator 12 and the positive output terminal of the power supply circuit 9, and the output terminal of the voltage comparator 12 is connected to the input terminal (E) of the microcomputer 10. When the voltage comparator 12 has a higher potential at point A, which is input to the non-inverting input terminal, than the potential at the output terminal of the D/A converter 34, which is output in response to the data at the output port (to) inputs a high level signal to the input terminal (E) of the microcomputer 10.

The microcomputer 10 outputs the binary data input to the D/Ai converter 32 starting from 0 and increasing by 1, thereby increasing the voltage at the inverting input terminal of the voltage comparator 120 in a stepwise manner. At this time, microcomputer 1
The binary data of the output port (to) at the time when the voltage of the input terminal (e) of 0 changes from high level to low level is
A method for determining a zero-order abnormal state that is detected as A/D conversion data of the potential at point A will be described.

The heater 6 used in this example is a semiconductor ceramic heater, and its characteristics are shown in FIG.

During normal operation, there is a stable point at point B in the diagram. If the heater 6 is energized with the motors not operating due to this failure and the air blowing not being activated, the surface temperature of the heater 6 will rise rapidly, but the characteristics are shown in Figure 3. As shown, the resistance of heater 6 also rises rapidly, reaching 10 at point B.
It becomes stable at the 0 point, which shows a resistance value of about 100%.

As shown in FIG. 2, in this embodiment, the potential at point A during normal operation is 6. ○■ indicates OSV when no air is blown.

If the microcomputer 10 determines that the magnitude of the current flowing through the heater 6 detected by the method described above is inconsistent with the state in which the microcomputer 10 itself is driving the load, it detects an abnormality. It is determined that the condition is the same.

That is, when the clock phenomenon of the motor 5 occurs, although the potential at point A shown in FIG. 1 should originally be about 5V, the potential at point A becomes 0.5V because air cannot be blown.
It's about one thing. In addition, if the energization control device 3 that controls the energization to the heater 6 is short-circuited or the lead wires are short-circuited for some reason and the energization to the heater 6 does not stop, the power supply to the heater 6 may not stop during the stop period or during cold air operation. Although the potential at point A should be ○V, a voltage of about 0.5V is detected.

When such an abnormal condition is detected, the microcomputer 10 outputs a voltage at the level of NO to the output port (A), operates the relay 3o, and stops the supply of power to the heater 6. , the buzzer 31 is sounded to notify the user of the abnormal condition.

The process of determining an abnormal state in the Cono Microcomputer 10 is as shown in FIG.

In addition, in the embodiment, when an abnormal condition is detected, the power supply to the heater 6 is stopped and the buzzer 310 sounds at the same time.
Effects of the Invention As mentioned above, in recent years, semiconductor ceramic heaters have been widely used as heat sources due to safety considerations, but due to malfunctions, electricity cannot be applied to the heaters when no air is being blown. If this happens, it cannot be said that it will immediately lead to a fire like when a nichrome heater is used heavily, but if this condition continues for a long time, the temperature inside the drum will rise and the clothes will become scorched. Furthermore, the possibility of fire cannot be denied if adverse conditions occur.

The clothes dryer of the present invention can prevent the heater from energizing when no air is being blown in all cases, and is extremely effective and safe from the viewpoint of protecting the texture of clothes and improving safety. This is of great significance considering the growing social demand for emphasizing

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between heater current and potential at point A in Fig. 1, and Fig. 3 is a semiconductor ceramic heater used in the embodiment. FIG. 4 is a flowchart showing the process of abnormal state determination. 1-・・・Regulation Department, 2, 3・・・Electrification control device, 4・・・Current detection device, 6・・・Motor, 6・・・Semiconductor ceramic heater , 10...ma'
+ Black computer, 11... Operational amplifier, 12.
...Voltage comparator, 32... D/A converter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Heat #, Ryo (A) Figure 3 Heat 9/) Surface temperature (σC) Figure 4

Claims (1)

[Claims] a semiconductor ceramic heater, a drum that accommodates clothing, and a motor that drives a fan that blows air into the drum;
An energization control device that controls the energization of the motor and the semiconductor ceramic heater, a current detection device that monitors the current status of the heater, and a control that receives the output of the current detection device and controls the operation of the energization control device. and has a
The control unit determines, as an abnormal state, a state in which a current value detected by the current detection device differs from a current value predicted to be normal in accordance with an operating condition of the energization control device.