JPS61109599A - Controller of 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 FIELD OF THE INVENTION The present invention relates to a control device for a dryer for drying clothes and the like with hot air.

Conventional Structure and Problems Generally, in a clothes dryer for drying clothes, the drying time varies depending on the amount and type of clothes.

For this reason, conventional clothes dryers are equipped with a mechanical timer, and the user has to set the operating time of the dryer using the timer.

In this case, if the time setting is incorrect, the clothes may become overdried and damaged, or may remain undried.

On the other hand, a device has been proposed that detects the dry state by detecting the resistance value of the clothes with electrodes and controls the operation, but when drying thick clothes, it is necessary to detect the resistance value of the surface of the clothes. In some cases, it was determined that the drying process was completed even though the drying process was not yet completed. When drying a small number of clothes, there is a drawback that there is little contact between the clothes and the electrodes, making it difficult to detect the dry state.

Furthermore, there is a method of detecting the dry state by detecting the exhaust temperature, but this requires correction for the ambient temperature and has problems such as low detection accuracy when the amount of cloth is small.

OBJECTS OF THE INVENTION The present invention aims to eliminate the drawbacks of the conventional main dryers mentioned above and provide a dryer control device that reliably detects the drying completion state and controls the operation regardless of the type or amount of clothes. It is.

Structure of the Invention In order to achieve the above object, the dryer control device of the present invention uses a piezoelectric element as a sensor, and when the cloth rotates in the drum due to the rotation of the drum, #f generated by the rotation of the cloth is detected.
It attempts to detect all dry conditions by detecting impact force.

Note that the impact force varies depending on the amount of cloth and the type of cloth, so remember the IF force at the start of operation and determine how much the impact force has decreased as the drying progresses compared to the impact force at the start of operation. This is used to detect dryness.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In Fig. 1, 1 is a piezoelectric element, 2 is a DC level converter that converts the voltage pulse corresponding to the impact force of the cloth by the piezoelectric element 1 into a DC voltage, and 3 is the output of the DC level converter 2 at the start of operation. A memory/calculation unit stores voltage, calculates the difference between the output voltage of the DC level conversion unit 2 during operation and the output voltage at the start of operation, and outputs the calculation result; 4 generates a certain specified standard voltage; A reference voltage generation section 5 is a comparison section that compares the output voltage of the memory operation section 3 and the output voltage of the reference voltage generation section 4, and the operation result of the memory operation section 3 is the reference voltage that is the output of the reference voltage generation section 4. When the above value is reached, a signal is output and the control section 6 is operated. The control unit 6 is a control unit that controls the motor that rotates the drum or fan of the dryer and the heater 8, and initially turns on the motor 7 and the heater 8.

When the output voltage of the comparison unit 5 is applied to the control unit 6, the motor 7
and turn off the heater 8.

FIG. 2 shows voltage waveforms at various parts of FIG. 1.

The horizontal axis is time, to is the time of start of operation, and tl is the time point when dryness is detected.

The voltage waveform of the person is the voltage waveform of the piezoelectric element, and is the voltage waveform of the piezoelectric element at t at the start of operation.

Since the cloth is wet, it is heavy and the impact force applied to the piezoelectric element is large, resulting in a large pulse voltage. Also, the impact force is not always applied, but as the drum rotates,
It may or may not be subjected to shock. As the cloth dries, the weight of the cloth becomes lighter and the impact force becomes smaller.
The generated pulse voltage also becomes smaller.

The DC level converter 2 converts this pulse voltage into a DC voltage according to its magnitude, and at the start of operation t.

Calculate the difference between the DC voltage and the DC output voltage during operation. This calculated output voltage is shown as B, and the reference voltage is shown as C.

The time t1 when the voltage B crosses the reference voltage cl is the dryness detection time.

As mentioned above, as dryness progresses and the weight of the cloth becomes lighter, dryness detection is performed by utilizing the fact that the impact force applied to the piezoelectric element 1 becomes smaller. Dryness can be detected easily and accurately without the need to make corrections for ambient temperature fluctuations, as is the case with exhaust temperature detection.

Further, by appropriately setting the output reference voltage of the reference voltage generating section 4, it is possible to stop the drying operation at a desired drying rate.

FIG. 3 shows a diagram in which a piezoelectric element is provided on the rotation bearing of the drum. 9 is a drum, 11 is a rotating shaft of the drum 9, and 1 is a piezoelectric element used as a drum rotation bearing. By providing the piezoelectric element 1 at the center of the drum in this manner, even when the amount of cloth is small, it is possible to reliably receive the impact of the cloth, so that accurate outside dryness detection can be performed.

According to the present invention, according to the control of the dryer, as the cloth dries, the weight of the cloth becomes lighter, and the piezoelectric element adds weight to the cloth. ＃Dryness detection is performed by detecting the decrease in impact force, and it is possible to perform simple and accurate dryness detection regardless of the type and amount of fabric, and is not affected by ambient temperature. can.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a control device for a dryer showing one embodiment, Fig. 2 is a voltage waveform diagram of each part of the control device for the dryer, and Fig. 3A is a transparent diagram of the dryer. The front view of FIG. 3 is a perspective side view of the same. 1... Piezoelectric element, 2... DC level conversion section, 3... Memory calculation section, 4... Reference voltage generation section, 5... Comparison part, 6... control part,
7...Motor, 8...Heater, 9...
...Drum, 11...Drum rotation axis. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 (Jt

Claims (2)

[Claims] (1) A piezoelectric element that detects the weight inside the dryer drum,
A DC level converter that converts the output voltage of this piezoelectric element into a DC voltage, and a DC level converter that stores the output voltage of the DC level converter at the start of operation, and the output voltage of the DC level converter at the start of operation and the DC level during operation. A memory operation section that calculates the difference in output voltage of the conversion section; a reference voltage generation section that generates a reference voltage; a comparison section that compares the output voltage of the memory operation section with the output voltage of the reference voltage generation section; A dryer control device consisting of a control section that controls the dryer motor and heater based on output voltage. (2) A control device for a dryer according to claim 1, wherein a piezoelectric element is attached to a bearing of a drum rotating shaft of the dryer.