JPS6032480B2 - clothes dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clothes dryer using a heater having a positive resistance temperature characteristic as a heat source.

Clothes dryers that use a heater with positive resistance-temperature characteristics (hereinafter simply referred to as a heater) as a heat source may suffer from problems such as the belt that rotates the blower fan coming off, or the motor that rotates the fan, drum, etc. breaking down. Even if an abnormal condition occurs such as no air passing through the heater, the heater is extremely safe because its maximum heat generation temperature is generally around 200oC and it does not become red hot.

However, since this heater has a low resistance at room temperature, a large current flows as an inrush current for a short period of time in a relatively small resistance range from when the power is turned on until the Curie point is reached, which may cause the power supply fuse to blow. There was a drawback that the flaker could be activated. The present invention provides a clothes dryer that can operate stably without tripping a breaker or the like when starting, that is, when the power is turned on. The rotation speed of the fan drive motor is set lower than the normal rotation speed for a predetermined period of time after the power is turned on, and the time during which a large current flows in the heater from the time the power is turned on until it reaches the Curie point. This will shorten the time.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1, 1 is a clothes dryer body equipped with a rotary drum 2 that can rotate freely, 3 is a fan case provided behind the rotary drum 2, and a rotary fan 4 is installed inside this fan case 3. ing.

Reference numeral 5 denotes a drum drive motor, and a drum rotation pulley 6 is fixed to a motor shaft 5' at both ends of the motor 5.
transmitted to.

7 is a fan drive motor, and a rotary fan 4 is fixed to a motor shaft 7'.

Reference numeral 9 denotes a plurality of baffles provided on the inner circumferential wall of the rotating drum 2, and is used to transfer the clothes IQ in the rotating drum 2.

This heater is provided below the rotating drum 2 and has positive resistance-temperature characteristics.

The heater blades 1' convert the cold air sucked in from the intake turtle 2 provided at the lower front surface of the main body 1 into hot air to the rotating drum 2.
It dries the clothes 10 inside. In addition, the moisture coming out of the clothing 10 is removed by the rotation of the rotating fan 4 along with the hot air.
The air is exhausted to the outside of the main body 1 through the exhaust port 13. 14 is a time switch; 15 is a door that closes the clothes input port 2' of the rotating drum 2; and 16 is a filter that collects stripes of lint generated within the rotating drum 2.

Figure 2 shows the control circuit of the dryer, where 17 and 1 are contacts in the time switch 14, turtle 7 is a contact for the heater, and 1 is a contact point in the time switch 14.
Reference numeral 8 is a motor contact, which serves as the main switch for motor 5 with a heater amount of 1.

11' indicates the plurality of heaters described above and indicates that they are provided via heater contacts 17.

The motor 5 is provided via a motor contact 1, and a fan drive motor 7 and a phase control circuit 19 for adjusting the rotation of the motor 7 by phase control are provided in parallel with the motor 5. The phase control circuit 19 includes a thermistor 2Q with negative temperature resistance characteristics, a resistor 21 and a capacitor 22.
It is composed of a bidirectional two-terminal control rectifying element 23t and a bidirectional three-terminal control rectifying terminal 24.Thermistor 2 is installed near the skin heater 11 and senses the temperature of the heater 1.Next, the operation is performed. Specifically, when the material to be dried IQ is placed in the rotating drum 2, the door 15 is closed and the time switch 14 is set, the heater contact 17 and the motor contact 1
8 is closed, and ``a plurality of heaters, motors 5, 7, and phase control circuit 19 are energized.'' This heater 1 is heated, the heater 5 is rotated, and the rotating drum is rotated at a predetermined number of rotations, for example, 48 to 53. Rotate at .pm to transfer the clothes inside.

When electricity starts, the temperature of the thermistor 20 installed near the heater 11 is lower than the stable temperature after a predetermined period of time after the start of operation, so the resistance value of the thermistor 20 is high and the capacitor 22 is charged. It takes time to
Therefore, the current flowing through the fan drive motor 7 is small.
The fan drive motor 7 rotates very slowly. As time passes, the temperature of the thermistor 20 increases due to the temperature influence of the heater 11, and the resistance value of the thermistor 20 decreases. Therefore, the time it takes to charge the capacitor 22 becomes gradually shorter, and the fan drive motor 7
The current flowing through increases. In other words, the fan drive motor T
will rotate farther as time passes. When the fan drive motor rotates, the fan 4 rotates and the hot air heated by the heater 1 exchanges heat with the material to be dried IQ, and then passes through the fan case 3 and is discharged from the exhaust port 13 to the outside of the machine.

Next, when the drying is finished, the heater contact 7 is turned off before the drying is finished, the heater 11 is no longer energized, the cold air operation is continued, and then after a certain period of time, the motor contact 18 is turned off. The device will turn off and display the message “Drying is complete.

Figure 3 shows the relationship between the passage of time and the heater current.
2 shows the case where, as in the conventional case, when the drying operation is started, the rotary drum 2 and the fan 4 are immediately rotated at a predetermined number of rotations at the same time as the heater 1 is energized.

Curve b' is the case of this example, and at the start of drying operation,
The case is shown in which the rotary drum 2 is rotated to a predetermined rotation speed at the same time as the heater turtle i starts being energized, and only the fan 4 is rotated slowly, and the rotation speed is gradually increased to the predetermined rotation speed as time passes.

According to the above configuration, the fan drive motor 7 rotates very slowly when the dryer starts operating due to the action of the phase control circuit 19.

Therefore, in the heater 11, the time from when the power is turned on until it reaches the Curie point is relatively short because the degree of cooling by the wind is small as in the conventional heater. Therefore, the time it takes for the heater current to reach a stable state is short, and because the time for large current to flow is short, there is no need for the circuit breaker to trip at the start of operation, which is the case with conventional methods.Furthermore, the fan Since the drum is equipped with a motor for driving the drum and a motor for driving the drum, the drum rotates normally even immediately after the power is turned on, which prevents burns and damage to clothing caused by abnormal heating near the heater due to power supply to the heater, and also prevents inrush current. As described above, the present invention provides motors for driving the drum and the fan, respectively, and for a predetermined period of time after power is turned on.
By setting the rotation speed of the fan drive motor lower than that during normal operation, it is possible to perform safe drying control that takes advantage of the characteristics of the heater, which has positive resistance-temperature characteristics. In this case, it is possible to shorten the time during which a large current flows through the heater due to its characteristics, and it is possible to prevent the inconvenience that safety devices such as thermal fuses and breakers operate even though they are unnecessary.

[Brief Description of the Drawings] Fig. 1 is a vertical cross-sectional side view of a clothes dryer according to an embodiment of the present invention, Fig. 2 is its electrical circuit diagram, and Fig. 3 is a diagram showing the relationship between time and heater current. It is. 2... Rotating drum, 4... Fan, 5, 7...
...Motor, 11... Heater, 19... Phase control circuit. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A clothes dryer in which air from a fan heated by a heater flows into a rotating drum, and after exchanging heat with the material to be dried, the air is discharged outside the drum. The heater has a positive resistance-temperature characteristic, and the number of revolutions of the fan driving motor is set at a constant speed after the elapse of the predetermined time period from power-on for a predetermined period of time. A clothes dryer comprising a control device that sets the temperature lower than that, the control device being a phase control circuit including a thermistor having a negative temperature resistance characteristic provided near the heater. 2. The clothes dryer according to claim 1, wherein the control device stops only the rotation of the fan drive motor for a predetermined period of time from when the power is turned on.