JP2951157B2 - Clothes dryer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clothes dryer.

[0002]

2. Description of the Related Art Conventionally, there are many clothes dryers using a positive resistance temperature characteristic heater as a heating means for heating drying air.

By the way, this type of heater has a characteristic that when the temperature on the input side changes, the resistance changes, and the amount of heat generated, that is, the input current to the heater changes. Further, the temperature on the input side is affected by the amount of air blown and the ambient temperature. For this reason, when the blown air amount is constant, when the ambient temperature decreases, the temperature on the input side of the heater decreases, the resistance of the heater decreases, and the input current increases.

Normally, in a clothes dryer, the capacity of a heater is determined so that a sufficient amount of heat can be obtained even when the ambient temperature is high, such as in summer. However, in this case, when the ambient temperature is low, such as in winter, the input current to the heater increases and the current consumption of the device itself becomes too large, exceeding the allowable current value of the commercial power supply for home use, and shutting off the breaker. There was a risk of doing so.

On the other hand, a current flowing through the heater is detected, and the heater is turned on and off so that the detected current value does not exceed a predetermined value, so as to prevent an increase in current consumption of the apparatus body. And disclosed in Japanese Patent Publication No. 2-9838 (D06F58 / 28).

[0006]

In the above-mentioned clothes dryer, the current is adjusted by ON / OFF control of the heater. In this case, the heater is cooled while the heater is turned OFF. When the heater is turned on, the heater must be heated again, and the heating efficiency is deteriorated.

Further, since the ON-OFF operation is frequently repeated, the life of the heater is shortened.

The present invention relates to an improvement in a clothes dryer, and solves such problems.

[0009]

Means for Solving the Problems According to claim 1 of the present invention.
Configuration, heat the drying air generated by the rotation of the blower fan
Supplied by heating at over data unit into the drying chamber, the clothes dryer for drying clothes accommodated in the drying chamber, the heat
When the heater device is composed of multiple positive resistance temperature characteristic heaters
In both cases, current detecting means for detecting current consumption of the apparatus main body when the heater device is energized , and rotational speed of the blower fan are detected.
A rotation speed detection means for knowledge, so that the current value detected by the current detector does not exceed a predetermined current value, and control means for adjusting the rotational speed of the blower fan, the control of the control means
The rotation speed of the blower fan decreases to a predetermined rotation speed below
The current value detected by the current detecting means is the predetermined current value.
If the value exceeds the value, the blower fan
Without reducing the rotation speed,
And second control means for reducing the number of heaters to be energized .

According to a second aspect of the present invention, a first aspect is provided.
In addition to the configuration according to the above, by the control of the second control means,
When the number of heaters to be energized decreases,
With a third control means for increasing the rotation speed of the
is there.

[0011]

[0012]

First, the blower fan is rotated at a preset number of rotations, and the air is input to the heater at a fixed airflow rate. When the input current increases because the ambient temperature is low and the temperature on the input side of the heater is low, the current detected by the current detecting means may exceed a predetermined current value. At this time, the number of rotations of the blower fan is reduced to reduce the amount of blown air. When the amount of air blows decreases, the temperature on the heater input side increases, so that the input current decreases. Thus, thereafter, the blower fan is driven at a rotation speed at which the detected current does not exceed the predetermined current value.

Here, the current detecting means may directly detect the current consumption of the apparatus main body, or may detect the current flowing through the heater and indirectly detect the current consumption. The predetermined current value is a value set so that the breaker does not shut off, and is, for example, an allowable current value of a commercial power supply for home use.

If the number of rotations of the blower fan is reduced and the amount of blown air becomes too small, the output side of the heater, that is, the vicinity of the outlet is locally heated, and there is a possibility that the nearby components may be overheated. For this reason, when the number of rotations of the blower fan decreases to a predetermined number, the rotation speed does not decrease below this value. At this time, if the detected current still exceeds the predetermined current value, the number of heaters to be energized is reduced to reduce the input current.

When the number of energized heaters is reduced, the input current is greatly reduced, but the amount of heat generated is also significantly reduced. At this time, the number of rotations of the blower fan is increased to increase the amount of blown air so that the heater that is energized can generate as much heat as possible.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

In FIG. 4, reference numeral 1 denotes a clothes dryer of the present embodiment, and reference numeral 2 denotes an outer frame of the clothes dryer, which has a clothes input port 3 on the front surface. Reference numeral 4 denotes a horizontal drum which is a drying chamber rotatably supported in the outer frame 2 and has an opening on the front surface corresponding to the clothes input port 3. An exhaust port 6 is provided in the center of the rear surface of the drum 4, and a lint filter 7 is disposed in the exhaust port 6. Reference numeral 2a denotes a support plate provided from the outer periphery of the clothing input port 3 and supporting the front surface of the drum 4. An intake port 5 is provided at a lower portion. Reference numeral 8 denotes a door for opening and closing the clothing slot 3.

Reference numeral 9 denotes a fan casing provided behind the drum 4, and reference numeral 10 denotes a heat exchange type double-sided fan provided so as to partition the fan casing 9 into a circulating air passage 11 and a cooling air passage 12. This is equivalent to the blower fan of the above. Reference numeral 13 denotes a communication port opened in the fan casing 9 for communicating the exhaust port 6 with the circulation air passage 11, and reference numeral 14 denotes a port for surely guiding dry air flowing out of the exhaust port 6 to the communication port 13. Seal member. 15 is the cooling air passage 1
An inlet 16 is provided at the center of the rear surface of the outer frame 2 for introducing the outside air into the inside 2, and an outlet 16 is also provided at a lower portion of the rear surface of the outer frame 2 for drawing the introduced outside air.

Reference numeral 17 denotes a circulating duct connecting the circulating air passage 11 and the intake port 5 of the drum 4, and a drain hole 18 is provided at a lowermost position. 19 is this circulation duct 17
The heater device is disposed on the side of the intake port 5 and includes two sets of honeycomb-shaped semiconductor heaters (positive resistance temperature characteristic heaters) of a first heater 19a and a second heater 19b. The heater device 19 includes a first heater 19a and a second heater 19b.
Is switched on or only the first heater 19a is turned on, thereby providing a high output (strong) and a low output (weak).
It becomes operable at The strength of the heater device 19 is determined by the drying operation course, but can be switched manually.

Reference numeral 20 denotes an induction motor, which is a drum pulley 2
1 and the drum 4 via a drum belt 22, and also to the double-sided fan 10 via a fan pulley 23 and a fan belt 24.

Thus, at the time of drying, the rotation of the motor 20 causes the drum 4 to rotate at a low speed and the double-sided fan 10 to rotate at a high speed. Double-sided fan 1
The drying air generated by the rotation of 0 and heated by the heater device 19 circulates through the circulation air passage 11, the circulation duct 17, and the drum 4, and exchanges heat with the clothes in the drum 4. At the same time, the outside air is introduced into the cooling air passage 12 by the rotation of the double-sided fan 10 to cool the double-sided fan 10 itself. Then, the drying air after the heat exchange in the drum 4 comes into contact with the double-sided fan 10 and is cooled, and the moisture in the drying air is condensed, flows down the circulation air passage 11, and is discharged from the drain hole 18. You.

A first member 25 is provided near the communication port 13.
Thermosensitive element. The first heat-sensitive element 25 detects the temperature of the exhaust air (drum outlet temperature) discharged from the drum 4 in order to detect the temperature inside the drum 4. 2
Reference numeral 6 denotes a second heat-sensitive element provided near the entrance of the heater device 19. The second heat-sensitive element 26 is connected to the double-sided fan 1.
The temperature of the drying air (heater inlet temperature) before the reheating by the heater device 19 after the heat exchange has been performed by 0 is detected. These first and second thermosensitive elements 2
5, 26, convert the detected temperature into an analog voltage value using a thermistor and output the analog voltage value. Then, the temperature data, which is the analog voltage value, is input to a microcomputer described later, is converted into a digital voltage value by an internal A / D converter, and is compared with a reference temperature previously stored in a storage unit. Thus, the temperature is determined.

Reference numeral 27 denotes a rotation sensor serving as rotation number detecting means for detecting the rotation number of the motor 20. The rotation sensor 27 includes a magnet piece 27a attached to the fan pulley 23 and a Hall IC 27b sensitive to magnetism generated by the magnet piece 27a. When the fan pulley 23, that is, the motor 20 makes one rotation, a pulse voltage is generated in the output of the Hall IC 27b, and the number of rotations of the motor 20 can be determined based on the generation cycle of this voltage.

FIG. 5 shows a control mechanism of the clothes dryer of this embodiment. Reference numeral 28 denotes a microcomputer, which is a control means, a second control means, and a third control means of the present invention. , A storage unit 30, a counter unit 31 including various counters, an A / D conversion unit 32, and the like. The storage unit 30 stores a reference current value and a commercial power supply allowable current value, which will be described later, in addition to the above-described reference values for the temperature and the rotation speed. These current values are
This serves as a comparison reference value for controlling the input current of the heater device 19.

Reference numeral 33 denotes various operation course selection keys 33a,
An operation key group 34 including a heater output switching key 33b and a start key 33c for starting / stopping a drying operation;
Is a door switch for detecting whether the door 8 is open or closed.

Reference numeral 35 denotes a current detection circuit serving as current detection means for detecting a current consumption of the device main body, a current transformer 35a for converting a current flowing through the device main body into a voltage, and a voltage value output from the current transformer 35a as a direct current. It comprises a rectifier circuit 35b for converting to a voltage value and a smoothing circuit 35c.

Numeral 36 denotes a zero-cross detection circuit which detects a zero-cross point which is a zero voltage point of the commercial power supply 37 and outputs a signal (synchronous signal) synchronized with the zero-cross point.

The operation key group 33, the door switch 34, the current detection circuit 35, and the zero-cross detection circuit 36
Is connected to the input side of the microcomputer 28 together with the thermosensitive elements 25 and 26 and the Hall IC 27b.

Reference numeral 38 denotes an LED display circuit connected to the output side of the microcomputer 28 for displaying the progress of the drying operation. Reference numeral 39 denotes a buzzer circuit for notifying the end of the operation or the operation abnormality.

40, 41 and 42 are the microcomputer 28
Is a triac that controls ON / OFF of the motor 20, the first heater 19a, and the second heater 19b, respectively, in accordance with a control signal from the controller.

Reference numeral 43 denotes a DC power supply circuit.
100V AC voltage to a relatively low DC voltage (for example, 5V
And 12V) and input to the microcomputer 28 as a power supply.

In the clothes dryer of the present embodiment, three patterns of automatic drying operation end detection are performed based on the temperatures detected by the first and second thermal elements 25 and 26. When any one of the three patterns is detected, the drying operation is terminated immediately or after a predetermined time is extended. Hereinafter, these automatic termination detection methods will be described.

First, according to the first end detection, after a predetermined time (for example, 15 minutes) from the start of the drying operation, that is, sufficient heat exchange is performed between the drying air and the clothes in the drum 4, and the drum outlet When the temperature becomes substantially constant, the first thermal element 25
The difference between the drum outlet temperature and the heater inlet temperature detected by the second thermosensitive element 26 is defined as a reference value A. Then, when the clothes are dried and the temperature at the drum outlet rises, the temperature difference widens, and when the temperature difference reaches a value (A + B) obtained by adding a predetermined value B to the reference value A, the end is detected.

According to the second end detection, after the start of operation or a predetermined time (for example, 30 minutes) after the start of operation, detection is performed by the first thermosensitive element 25 and the second thermosensitive element 26. When the difference between the drum exit temperature and the heater entrance temperature reaches a preset limiter value, the end is detected.

According to the third end detection, when the drum outlet temperature detected by the first thermosensitive element 25 reaches a preset high limiter value, the end is detected.

The reason why the end detection is performed by a plurality of methods is to perform better automatic end detection corresponding to the type and amount of clothing.

Here, the B value, the limiter value, and the high limiter value are determined by various experiments performed by changing the type and amount of clothing, and are stored in the storage unit 30.

Next, the operation of this embodiment based on the above configuration will be described with reference to the flowcharts of FIGS.

First, when the start key 33c is pressed,
The drying operation is started, and the motor 20 is turned on. Motor 2
The target rotation speed of 0 is set to the minimum rotation speed of 1150 rpm in the rotation speed control of the present embodiment, and the first heater is turned on.
Then, the rotation speed of the motor 20 is controlled so as to reach the set target rotation speed (S1 to S8).

In the rotation speed control of this embodiment, phase control for controlling the rotation speed by adjusting the phase of the power supplied to the motor 20 is employed. As shown in FIG. 6, this phase control is synchronized with a zero cross point (phase angle 0 °) detected by the zero cross detection circuit 36, and is delayed from the zero cross point by a predetermined phase angle (0 to 180 °). Output a motor ON signal from the microcomputer 28 to turn on the motor 20
It is something to do. The predetermined phase angle, that is, the phase angle at which the motor 20 is energized (referred to as a conduction angle)
Is adjusted so that the desired rotational speed can be obtained.
This adjusts the amount of power supplied to the power supply. FIG.
(A) is the voltage waveform of the power supply, (B) is the synchronization signal of the zero-cross point output from the zero-cross detection circuit 36, (C)
Represents a motor ON signal output from the microcomputer 28, and (d) represents a voltage waveform supplied to the motor 20 as a result of the phase control.

When two minutes have elapsed from the start of drying, the second heater is turned on, and the heater device 19 is operated "strongly" (S6).
S7).

In the positive resistance temperature characteristic heater used in the present embodiment, a large rush current flows at the beginning of energization because the heater is cold. Therefore, as described above, the first heater 19a is first turned on, and the second heater 19a is turned on.
The second heater 19b may be turned on after warming itself or the drying wind, or the motor 20 may be rotated at a rotational speed as low as possible to drive the double-sided fan 10 at a low speed to reduce the amount of air blown to the heater device 19. By doing so, a large inrush current is prevented. However, even in this case, the allowable current value of the commercial power supply in the home may exceed 15 A, but since this is a short time, the breaker is not shut off.

When the first and second heaters 19a and 19b are energized together and the heaters themselves become stable, the heater device 19
The current flowing through the power supply drops to a substantially constant value. The input current value at this time varies depending on the temperature on the input side of the heater device 19. That is, if the temperature on the input side is low, a large current flows. For this reason, even if the current flowing through the heater is stable, if the ambient temperature is low in winter and the input side temperature is low, a current exceeding the allowable current value of the commercial power supply of 15 A will continue to flow for a long time, and the breaker will shut off. There is a fear.

Therefore, in order to prevent this, the present invention operates as follows. When 10 minutes have elapsed from the start of the drying operation, the current detection circuit 35 detects the current consumption (I) of the device main body. The current value at this time is compared with the reference current value 14.3A stored in the storage unit 30, and 14.3A
If this is the case, the target rotation speed of the motor 20 is reduced and 1
If it is smaller than 4.3A, the target rotation speed is increased. Thereafter, the target rotation speed is changed every second, and the target rotation speed is adjusted in the range from the maximum rotation speed of 1400 rpm to the minimum rotation speed of 1150 rpm (S10 to S21). Then, based on the target rotation speed, the motor 20
Is performed.

As described above, when the rotation speed of the motor 20 changes, the rotation speed of the double-sided fan 10 changes, thereby changing the air blowing amount. Then, the temperature on the input side of the heater device 19 changes, so that the input current value of the heater device 19 changes and the current consumption value of the device main body changes.

As described above, the input current of the heater device 19 is adjusted by adjusting the number of revolutions of the motor 20, and the current consumption of the apparatus main body is maintained at the reference current value of 14.3A.
As a result, the maximum heat generation amount can be output without exceeding the commercial power supply allowable current value of 15A. Note that the commercial power supply allowable current value 15A corresponds to the predetermined current value in the present invention.

Here, when the target rotational speed is the minimum rotational speed 1150
Even when the motor 20 is operated at this speed, the consumption current may not be lower than the allowable current value of the commercial power supply 15 A when the ambient temperature is extremely low. In such a case, if the rotation speed of the motor 20 is further reduced, the rotation speed of the double-sided fan 10 becomes too small and the air blowing amount becomes too small, and the output side of the heater device 19, that is, the vicinity of the outlet is locally reduced. There is a possibility that the temperature may rise to overheat the nearby components. In addition, the rotation speed of the drum 4 may be too low, and the clothes in the drum 4 may not be stirred smoothly. Therefore, the rotation speed of the motor 20 is not reduced below the minimum rotation speed.

As a countermeasure for such a case, even if 15 minutes have passed since the start of the drying operation, the current consumption of the apparatus body exceeds the allowable current value of the commercial power supply of 15 A, and if this continues for 1 minute, the weak turbo flag is set. Is set (S21-S
27). When it is determined in S10 that the weak turbo flag is set, the second heater 19b is stopped, and the heater device 19 is changed to "weak" operation. Accordingly, the target rotation speed is set to the maximum rotation speed of 1400 rpm, and rotation control is performed (S28, S29, S8).

By setting the heater device 19 to "weak", the input current is reduced by almost half, and the heat generation is reduced by that much. However, at this time, the input current is increased by increasing the rotation speed of the motor 20 to the maximum rotation speed of 1400 rpm to increase the amount of air blow, and the first ON state
The amount of heat generated by the heater 19a is made as large as possible.

Thus, when the drying operation proceeds and the clothes are dried, and any of the three patterns described above is automatically detected, the first heater 19a and the second heater are turned off and the motor 20 is turned off. And the operation is terminated (S9, S30).

FIG. 3 shows how the current consumption of the apparatus main body varies with the operating time. The solid line in the figure is
The change in the input current of the heater device 19 is controlled by adjusting only the double-sided fan 10, and the one-dot chain line indicates that the ambient temperature is very low. 10 shows a change state when the number of rotations of 10 is increased.

[0052]

According to the first aspect of the present invention, the input current of the heater is adjusted so that the current consumption of the main body does not exceed the predetermined current value. It can be prevented from being shut off.

The adjustment of the input current is performed by turning the heater on and off.
Since the rotation is controlled by controlling the number of rotations of the blower fan and adjusting the blowing amount without N-OFF, the heating efficiency is not unnecessarily deteriorated and the life of the heater is shortened. Not even.

Further , when the current consumption of the apparatus main body does not become lower than the predetermined current value even when the rotation speed of the blower fan is reduced to the predetermined rotation speed, the heater to be energized without lowering the rotation speed of the blower fan is used. , The input current is suppressed, so that it is possible to surely prevent an increase in the current consumption of the device main body without causing a high temperature near the heater outlet due to a large decrease in the amount of blown air.

According to the configuration of the second aspect of the present invention, when the number of heaters to be energized is reduced and the amount of heat generation is greatly reduced, the rotation speed of the blower fan is increased to increase the amount of blown air and energize. Since the heater generates as much heat as possible, even if the number of energized heaters is reduced, the heating efficiency is not significantly reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the operation of the clothes dryer of the present invention.

FIG. 2 is a flowchart subsequent to FIG. 1;

FIG. 3 is a diagram illustrating a relationship between an operation time and a current consumption of a device main body.

FIG. 4 is a side longitudinal sectional view showing the configuration of the clothes dryer of the present invention.

FIG. 5 is a block diagram showing a control mechanism.

FIG. 6 is a diagram illustrating waveforms when performing phase control.

[Explanation of symbols]

Reference Signs List 4 drum (drying chamber) 10 double-sided fan (blowing fan) 19 heater device 27 rotation speed sensor (rotation speed detection unit) 29 control unit (control unit, second control unit, third control unit) 35 current detection circuit ( Current detection means)

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-99600 (JP, A) JP-A-62-164498 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) D06F 58/28

Claims (2)

(57) [Claims] 1. A clothes dryer for heating drying air generated by rotation of a blowing fan by a heater device and supplying the drying air to a drying chamber, and drying clothes housed in the drying chamber.
The heater device includes a plurality of positive resistance temperature characteristic heaters.
While a current detecting means for detecting the current consumption of the main body at the time of energization of the heater device, the rotation of the blowing fan
A rotation speed detecting means for detecting the number, so that the current value detected by the current detector does not exceed a predetermined current value, and control means for adjusting the rotational speed of the blower fan, the control means
Under the control, the rotation speed of the blower fan is reduced to a predetermined rotation speed.
The current value detected by the current detecting means
If the current exceeds the constant current value, the blower fan
Without lowering the rotation speed of the fan.
And a second control unit for reducing the number of heaters to be energized . 2. The method according to claim 1, further comprising :
When the number of heaters to be turned on decreases,
The clothes dryer according to claim 1, further comprising third control means for increasing the number of revolutions .