JP3109277B2 - Clothes dryer - Google Patents

Abstract

PURPOSE:To keep the heating current of a PTC heater without exceeding the maximum set value by controlling the rotational frequency of a heat exchange fan and by controlling the heating power of a clothes drier to maximum. CONSTITUTION:A PTC heater 3 is provided in an air blowing path into a rotary drum 1 for drying clothes, and the rotary drum 1 and a heat exchange fan are rotary driven by a motor 4 to circulate hot air into the rotary drum 1 by the heat exchange fan. The clothes drier comprises the rotary drum 1, a rotation detecting means 5 for detecting the rotational frequency and the rotating period of a motor 4 or the like, a rotation control means 6 for controlling the rotational frequency of the motor 4, a current detecting means 7 for detecting the current of the PTC heater 3, and a current comparing and setting means 8 for inputting the output of the current detecting means 7, wherein the rotation control means 6 controls the preset rotational frequency and the preset rotating period of the rotary drum 1 and the motor 4 according to an output signal of the current comparing and setting means 8. The rotation of the rotary drum 1 and the heat exchange fan is stabilized to control the heater current to the optimum value and increase the heating output to maximum so that the drying time can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, household clothes dryers have been provided with a positive characteristic temperature-sensitive heater (hereinafter, referred to as a PTC heater) as a heating means to prevent burning of clothes due to an increase in overheating temperature. However, since the inrush current of the PTC heater is large, and the heater current is large at a low temperature, there is a possibility that a home breaker may operate. Therefore, a clothes dryer that powers down when the current becomes 15 A or more, for example, has been proposed.

Conventionally, this type of clothes dryer has been disclosed in
No. 900900. That is, a change in the current of the PTC heater is detected by a current measuring device, and the blower capacity of the fan device is reduced as the current value increases.

[0004]

In such a conventional clothes dryer, the current of the PTC heater is detected to control the blowing capacity of the fan device, and when the current of the PTC heater is large, the rotation speed of the blowing fan is reduced. As a result, the rotational speed becomes unstable. In particular, the change in the current of the PTC heater is large for a few minutes immediately after the start of the drying operation. It is possible that the rotation of the fan stops. In addition, when the power supply voltage decreases, the current of the PTC heater increases. However, when the rotational speed of the blower fan is reduced, the motor voltage for driving the blower fan also decreases, so that the motor rotation stalls. There was a case.

[0005] The present invention solves the above-mentioned conventional problems.
Rather than directly controlling the number of revolutions of the blowing means by changing the current of the PTC heater, the PTC heater current is controlled so that the indoor wiring breaker at home is not operated while stably controlling the number of revolutions of the blowing means and the rotating drum. The purpose is to obtain the maximum heating output and shorten the drying time.

[0006]

According to the present invention, there is provided a rotating drum for drying clothes, a blowing means for circulating warm air into the rotating drum, and a blowing path into the rotating drum. A PTC heater, a motor for rotating the blower and the rotary drum, a rotation detector for detecting a rotation speed or a rotation cycle of the rotary drum and the motor, and a rotation for controlling the rotation speed of the motor. and control means, wherein the includes a current detecting means for detecting a PTC heater current, a current comparator setting means for inputting an output of said current detecting means, the rotation control means, during the rotation start or
Or the set rotation speed or on / off control of the PTC heater.
A rotation speed control mode that controls the set rotation cycle at a constant
Set rotation of rotating drum by output signal of flow comparison setting means
Control by current control mode that controls number or rotation cycle
The upper and lower limit values for the set number of revolutions of the rotating drum.
Is provided as a first problem solving means.

[0007] Further, a rotating drum for drying clothes, blowing means for circulating warm air into the rotating drum, a PTC heater provided on a blowing path into the rotating drum, and the blowing means or the rotating drum. A rotating motor, a rotating drum, rotation detecting means for detecting the number of rotations or a rotation cycle of the motor, and rotation control means for controlling the number of rotations of the motor; In the above, there is provided a rotation speed control mode period in which the rotation speed or the rotation speed of the rotation drum or the motor or the like is set to be low and controlled, and the PTC heater is delayed and turned on after the rotation of the motor is started. Is the second means for solving the problem.

[0008]

According to the first aspect of the present invention, there is provided:
While controlling the motor speed to stabilize the speed,
The breaker can be prevented from operating by controlling the set rotation speed of the motor that drives the blower so that the current consumption of the PTC heater is equal to or less than a certain value. In addition, since the rotation speed and the current consumption can be controlled regardless of the AC power supply frequency of 50 Hz or 60 Hz, a clothes dryer that does not require component replacement according to the power supply frequency can be realized.

In addition, the amount of air blown at the start of operation is reduced to reduce
Not only can the inrush current of the TC heater be reduced,
The motor control speed can be stabilized by the rotation control mode that keeps the rotation speed constant against the inrush current change due to the heater on / off, and the increase in noise due to the motor rotation stall and the change in the rotation speed of the blower is prevented. it can.

Further, when the ambient temperature at which the dryer is installed is detected, and when the ambient temperature is low in winter or the like, the amount of air can be increased to increase the heating output of the PTC heater and shorten the drying time. When the ambient temperature is high, such as in summer, the drying time is short, so that the power consumption of the PTC heater can be reduced by reducing the heating output of the PTC heater.

An upper limit value and a lower limit value are provided for the set number of revolutions or the set cycle of the rotating drum or the motor, so that the motor rotation can be prevented from stalling and unstable operation at low speed rotation, and the noise of the blower fan at high speed rotation Can be suppressed.

Further, according to the second means for solving the problem, the PTC heater is turned on after the rotation of the motor is started and the rotation speed is stabilized, so that an increase in the heater current due to the rotation speed overshoot at the start of the motor can be prevented. In addition, it is possible to reduce the influence of disturbances such as a decrease in the motor speed due to a decrease in the power supply voltage due to a rush current when the heater is turned on and an unstable speed control.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the rotating drum 1 stores the material to be dried, and circulates warm air in the rotating drum 1 by a heat exchange fan (blowing means) 2. The heat exchange fan 2 circulates warm air in the rotating drum 1 and simultaneously takes in air from the outside to cool the fan and dehumidifies the circulating air in the rotating drum 1. The PTC heater (heating means) 3 is disposed in a blowing path to the rotating drum 1, that is, in a circulating air intake, and heats the circulating air. The motor 4 drives the rotary drum 1 and the heat exchange fan 2 to rotate. By controlling the number of revolutions of the motor 4, the number of revolutions of the rotary drum 1 and the heat exchange fan 2 can be controlled, and the amount of heat generated by the PTC heater 3 can be controlled, thereby enabling current control. The rotation detecting means 5 detects the number of rotations of the rotating drum 1, and a magnet 50 is provided on the rotating drum 1.
3 to 6, the output of the magnetic sensor 51 is input to the rotation speed detecting means 52 to detect the rotation speed of the rotating drum 1,
The output is input to the rotation control means 6 to control the rotation speed of the motor 4 to a set rotation speed. By doing so, the motor 4
In addition to stable control of the rotational speed of the rotary drum 1, it is possible to detect a slip or disconnection failure of a belt serving as a rotation transmitting means between the rotary drum 1 and the motor 4.
The rotation detecting means 5 may detect the rotation period of the rotating drum 1, and the rotation speed can be controlled by detecting the rotation speed or the rotation period of the motor 4 or the heat exchange fan 2. Needless to say.

The rotation control means 6 controls the set rotation speed or the set cycle of the rotation speed setting means 60 according to the signal of the current comparison setting means 8 which receives the signal from the current detection means 7 of the PTC heater 3, The difference between the rotation speed of the rotary drum 1 detected by the rotation detection unit 5 and the rotation speed set by the rotation speed setting unit 60 is compared by the rotation speed comparison unit 61, and the conduction time control unit 62 and the bidirectional thyristor (power control) are compared. Means) 63
To control the rotation speed of the motor 4. The simplest power control method is phase control, but an inverter may be used. The current comparing and setting means 8 is composed of a current setting means 80 and a current comparing means 81, and the output signals of the current detecting means 7 and the current setting means 80 are compared by the current comparing means 81 so that the current value becomes a set value. Speed setting means 60
Change the setting signal of. The rotation speed fixing means 64 is a motor 4
When the rotation is started, the set value of the rotation speed setting means 60 is forcibly reduced, and the rotation speed at the time of startup is reduced regardless of the magnitude of the signal of the current comparison setting means 8. The ambient temperature detecting means 9
Temperature sensor 90 such as thermistor and set current changing means 9
The current setting value of the current setting means 80 is controlled to an optimum value according to the ambient temperature. The power switching means 10 includes a PT
Relay contacts 10a and 10 in series with C heaters 3a and 3b
b to control the conduction of the PTC heaters 3a and 3b. Reference numeral 11 denotes an AC power supply.

The heat exchange fan 2 is installed coaxially with the rotary drum 1, circulates the air in the rotary drum 1, cools the humid air and dehumidifies it, and sends the dehumidified air to the PTC heater 3. The motor 4 drives the rotary drum 1 and the heat exchange fan 2 with the rotary drum belt and the fan belt. Magnet 5
Numeral 0 is attached to the rotating drum 1 and the magnetic sensor 51 is fixed to the housing.

In the above configuration, the soft start at the start of operation will be described with reference to FIGS. 3 (a) and 3 (b). FIGS. 3 (a) and 3 (b) show the relationship between the rotational speed N and the current consumption I. At the start of the operation, the operation is set to the minimum rotation speed Nmin and the operation is performed in the rotation speed control mode.
After a few minutes, the current control mode is entered, and the set rotation speed of the motor 4 is increased by the output signal of the current comparison and setting means 8, whereby the rotation speed gradually increases to reach the maximum rotation speed Nmax. When the motor 4 is started, the number of revolutions is reduced, and only the air blowing operation of the heat exchange fan 2 consumes less current. After the motor 4 starts, one PTC heater 3a is turned on at time T1, and then the other PTC heater 3b is turned on at time T2. The inrush current of the PTC heater 3 can be reduced by the low speed rotation of the heat exchange fan 2 and the delay operation of the power switching means 10. When motor 4 starts, PT
Since the C heater 3 is in the off state, the voltage drop is small, and the motor 4 is easily started. Thereafter, at time T3, the rotation speed set value is controlled such that the current value becomes the set value by changing from the rotation speed control mode to the current control mode.
In the current control mode, when the intake air temperature of the PTC heater 3, that is, the circulating air temperature increases, the heating power of the PTC heater 3 decreases even if the rotational speed of the heat exchange fan 2 increases, so that the rotational speed gradually increases. . Since the noise increases as the rotation speed increases, the upper limit value is controlled so as not to exceed the maximum rotation speed Nmax. Also, if the number of rotations is too low, the cloth rotation becomes worse, so the number of rotations of the rotating drum 1 is limited to 35 to 45 rpm, and upper and lower limits are provided.

The rotation speed of the motor 4 is controlled as shown in FIGS. That is, FIG.
4 (b) is a zero-voltage pulse signal, and FIG. 4 (c) is a trigger pulse signal of the bidirectional thyristor 63, which is applied to the motor 4 by controlling the time t from the zero voltage of the AC voltage 11. The effective voltage is controlled to control the number of revolutions. In the so-called phase control, the time t corresponds to the phase angle. FIG. 4D shows a motor current waveform. By performing feedback control on the time t from the zero voltage, that is, the phase angle according to the rotational speed error from the set rotational speed Ns, the rotational speed of the motor 4 can be controlled to the set value.

Generally, the drying time varies depending on the ambient temperature at which the dryer is installed. As shown in FIG. 5, by controlling the current set value of the current comparison and setting means 8 by the output of the ambient temperature detecting means 9, as shown in FIG. On the other hand, when the ambient temperature is low in winter or the like, the current setting value of the PTC heater 3 is increased to shorten the drying time. At this time, it goes without saying that control can be performed so as not to exceed a certain current. Also,
When the ambient temperature is high, such as in summer, the drying time is short, so that the heater current set value can be reduced to reduce power consumption.

Next, the start rotation control, that is, the power control based on the soft start and the rotation control will be described with reference to FIG. 6. In step 101, the operation is started. In step 102, the ambient temperature is detected and the heater control current value is detected. Set. In step 103, the initial rotation speed is set to the lowest controllable rotation speed, only the motor 4 is started to rotate in step 104, and after a delay operation of 10 to 20 seconds in step 105, the PTC heater 3a is energized in step 106. . Next, after a delay operation of 20 to 30 seconds in step 107, the PTC heater 3b is energized. Step 109 is a current control (power control) subroutine, which detects the heater current after the elapse of the delay time when the inrush current of the PTC heater 3b has decreased, calculates the error with the heater current set value set in step 102, and calculates the error. The number of rotations of the motor 4 is controlled according to the amount of the PTC heater 3a,
Control the 3b current. Step 110 is a rotation speed control subroutine, which detects the rotation speed of the motor 4 or the rotating drum 1 and, based on the error between the rotation speed set by the current control subroutine of step 109 and the detected rotation speed, calculates the zero voltage pulse ZVP. Is controlled by controlling the phase of the time t. It is determined in step 111 that the drying has been completed. If the drying has been completed, the process proceeds to step 112 and the operation ends.

The details of the current control subroutine and the rotation control subroutine of steps 109 and 110 will be described with reference to FIG. 7. In step 113, a timer flag for operating every second is detected.
In step 115, the heater current I is detected. In step 115, the error between the set value Is and the detected current I is detected.
In step 6, a set rotation speed or a set rotation period Ts is calculated according to the current error amount. Step 117 and Step 11
8 limits the maximum rotation cycle (rotational speed lower limit).
If the calculated rotation cycle Ts is equal to or greater than the maximum value Tsmax, the rotation cycle Ts is set to the maximum value Tsmax. Step 11
Steps 9 and 120 limit the rotation period to the minimum rotation period (upper limit of the number of rotations). If the calculated rotation period Ts is equal to or smaller than the minimum value Tsmin, the rotation period Ts is set to the minimum value Tsmin. Next, the signal from the rotation detecting means 5 is detected in step 121, and the rotation period T is detected in step 122. The amount of error between the rotation period T detected in step 123 and the set rotation period Ts is detected.
If the error amount is equal to or more than the set value in 25, the control time t is controlled according to the error amount, and the rotation period is controlled so as to become the set rotation period.

In the above embodiment, the control is performed by detecting the rotational speed of the rotary drum 1. However, the same effect can be obtained by detecting and controlling the rotational speed of the motor 4 or the heat exchange fan 2. Also, not only the current of the PTC heater 3 but also the motor 4
The same effect can be obtained by detecting and controlling the consumed current including the above current. Further, although the rotation speed of the motor 4 is controlled by the phase control, it goes without saying that the same effect can be obtained by controlling the rotation speed of the motor 4 by the inverter.

[0023]

As is apparent from the above embodiments, according to the present invention, a rotating drum for drying clothes, a blowing means for circulating warm air into the rotating drum, and a blowing path to the rotating drum A PTC heater, a motor for rotating the blower and the rotary drum, a rotation detector for detecting a rotation speed or a rotation cycle of the rotary drum and the motor, and a rotation for controlling the rotation speed of the motor. Control means, current detection means for detecting the current of the PTC heater, and current comparison setting means for inputting the output of the current detection means, wherein the rotation control means is configured to output the current by the output signal of the current comparison setting means. Since the set rotation speed or the set rotation cycle of the rotating drum and motor are controlled, the stable rotation speed of the rotating drum or the air blowing means regardless of the AC power supply frequency The resulting, and since the heater current does not become more than a predetermined value, it is not possible to secure the breaker is operated. Further, the maximum heating output can be obtained, and the drying time can be shortened.

Further, the rotation control means includes a rotation number control mode for controlling the set number of rotations or the set number of rotations to be constant at the time of start of rotation or on / off control of the PTC heater, and setting of the rotating drum based on an output signal of the current comparison setting means. Since it has a current control mode for controlling the number of rotations or a rotation cycle, it is possible to lower the set number of rotations at the start of operation and to perform a soft start in the number of rotations control mode for controlling the number of rotations to be constant. The inrush current can be reduced, and the problem that the current control works and the rotation becomes unstable is eliminated.

Further, since the set current value of the current comparison setting means is changed according to the ambient temperature, when the ambient temperature is low, the set value of the current comparison setting means is increased to increase the heating power. The drying time can be shortened even at low temperatures such as in winter.

The rotation control means includes a rotation speed setting means such as a rotary drum and a motor, a rotation speed comparison means for controlling the rotation speed to a set rotation speed, and a power control means. Since the set number of revolutions of the rotating drum is controlled and upper and lower limit values are provided for the set number of revolutions of the rotating drum and the motor, noise when the number of revolutions is high can be reduced. It is possible to prevent the cloth rotation problem.

[0027] Further, a rotating drum for drying clothes, blowing means for circulating warm air into the rotating drum, a PTC heater provided in a blowing path into the rotating drum, and the blowing means or the rotating drum. A rotating motor, a rotating drum, rotation detecting means for detecting the number of rotations or a rotation cycle of the motor, and rotation control means for controlling the number of rotations of the motor; In the above, there is provided a rotation speed control mode period in which the set rotation speed or the rotation cycle of the rotating drum or the motor is set low and controlled, and the PTC heater is delayed and made conductive after the motor starts rotating. Then, the motor is started to rotate while the PTC heater is turned off, and after the rotation speed reaches the set low-speed rotation speed, the PT
The C heater can be sequentially energized, so that not only the rush current of the PTC heater can be reduced, but also the problem that the motor rotation becomes unstable due to the voltage drop of the AC power supply due to the rush current, or the starting failure can be prevented. .

[Brief description of the drawings]

FIG. 1 is a block diagram of a clothes dryer according to one embodiment of the present invention.

FIG. 2 is a sectional view of the clothes dryer.

3 (a) and 3 (b) are diagrams showing time variations of rotation speed and current for explaining rotation control of the clothes dryer.

4 (a) to 4 (d) are waveform diagrams of respective parts of rotation speed control by phase control of the clothes dryer.

FIG. 5 is a current control characteristic diagram according to the ambient temperature of the clothes dryer.

FIG. 6 is a main part flowchart for explaining the operation of the clothes dryer.

FIG. 7 is a flowchart illustrating a current control operation of the clothes dryer.

[Explanation of symbols]

 Reference Signs List 1 rotating drum 2 heat exchange fan (blowing means) 3 PTC heater (heating means) 4 motor 5 rotation detecting means 6 rotation control means 7 current detecting means 8 current comparison setting means

Continuation of front page (56) References JP-A-3-284299 (JP, A) JP-A-63-89200 (JP, A) JP-A-2-239900 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) D06F 58/28

Claims (2)

(57) [Claims] A rotating drum for drying clothes; a blowing means for circulating warm air into the rotating drum; a heating means comprising a positive characteristic temperature-sensitive heater provided in a blowing path into the rotating drum; A motor that rotationally drives the blower and the rotary drum, a rotation detector that detects a rotation speed or a rotation cycle of the rotary drum, the motor, and the like; a rotation controller that controls the rotation speed of the motor; Current detecting means for detecting a current; and current comparing and setting means for inputting an output of the current detecting means, wherein the rotation control means is set at the time of starting rotation or at the time of on / off control of the heating means.
Rotational speed system that controls constant rotation speed or set rotation cycle
Control mode and the output signal of the current comparison setting means.
The power for controlling the set rotation speed or rotation cycle of the rotating drum
Flow control mode.
Clothes dryer with upper and lower limits for the set number of rotations of the system . 2. A rotating drum for drying clothes, a blowing means for circulating warm air into the rotating drum, a heating means comprising a positive characteristic temperature sensitive heater provided in a blowing path into the rotating drum, A motor for rotating the blower or the rotary drum; a rotation detector for detecting a rotation speed or a rotation cycle of the rotary drum or the motor; and a rotation controller for controlling the rotation speed of the motor. The control means, at the time of rotation start, provides a rotation number control mode period for setting and controlling a set rotation number or rotation cycle of the rotating drum or the motor to be low, and delays the heating means after the motor starts rotation. Clothes dryer which is designed to conduct electricity.