JPH0759994A - Electric dryer for clothes - Google Patents

Abstract

PURPOSE:To stop the current carrying to a heating means, and the rotation of a rotary drum, by detecting that an abnormal condition is generated in a blower means accurately, in any electric dryer to dry clothes by circulating a hot air to the rotary drum driven and rotated by a motor. CONSTITUTION:A hot air is circulated inside a rotary drum 1 to dry clothes by a heat exchange type double blade fan, a PTC heater 3 is attached on an air blowing passage to the inside of the rotary drum 1, and the rotary drum 1 and the heat exchange type double fan are driven and rotated by a motor 5. A relay 23 is connected in series to the PTC heater 3, and a current detecting means 16 to detect the current of the PTC heater 3 is disposed. When the output of the current detecting means 16 becomes a set value or less at the time of carrying current to the PTC heater, an abnormality detecting means 20 operates to turn off the relay 23 once, and to turn on again at least one round, and after that, when the output of the current detecting means 16 becomes the specific or less again, the abnormality detecting means 20 detects the abnormal condition, so as to stop the heating of the PTC heater 3, and the rotation of the rotary drum 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clothes dryer which circulates warm air in a rotary drum which is driven by a motor to dry clothes.

[0002]

2. Description of the Related Art In recent years, household clothes dryers have become widespread, and there is a demand for clothes dryers having a positive temperature characteristic heater to improve safety.

Conventionally, this type of clothes dryer has been disclosed in Japanese Utility Model No. 62.
It was constructed as shown in Japanese Patent Publication No.-90098. That is, a positive temperature characteristic heater (hereinafter referred to as PTC heater)
When the heater current is increased by detecting the current of the fan, the blower fan capacity is controlled.

[0004]

In such a conventional clothes dryer, since the heater current decreases when the blower fan stops, the motor or the rotating drum rotates at a high speed so as to increase the heater current. Had a problem above. In particular, when the fan belt that transmits the rotational torque from the motor that rotationally drives the blower fan is transmitted to the blower fan,
Alternatively, when the opening / closing means such as a relay for controlling the opening / closing of the heater current has an open circuit failure, the motor has a problem of abnormal rotation.

The present invention solves the above-mentioned problems. There are few malfunctions, and only when an abnormality occurs in the operation, the failure content can be reliably distinguished and notified, the heating of the PTC heater is stopped, and the rotation of the motor is stopped. The purpose is to stop.

[0006]

In order to achieve the above object, the present invention provides a rotating drum for drying clothes, an air blowing means for circulating warm air into the rotating drum, and an air blowing path into the rotating drum. A heating means provided in the motor, a motor for rotating the air blowing means or the rotary drum, an opening / closing means for controlling the heating means, a current detecting means for detecting a current of the heating means, and a power supply for the heating means. When the output of the current detecting means is less than or equal to the set value, after the operation of turning off the opening / closing means and turning it on again at least once, and then the output of the current detecting means is again less than or equal to the set value. The first problem solving means is to have an abnormality detecting means for detecting an abnormal state.

In addition to the first means for solving the above problems,
A rotation detecting means for detecting the number of rotations or a rotation cycle of the rotating drum or the motor is provided, and the abnormality detecting means detects an abnormal state when the number of rotations detected by the rotation detecting means is equal to or more than a predetermined number of rotations. This is the second means for solving the problem.

Further, the heating means and the opening / closing means of the first problem solving means are each divided into a plurality of parts, and the abnormality detecting means turns on the opening / closing means one by one at a predetermined time, and all the opening / closing means. The third problem solving means is to detect an abnormal state when the output of the current detection means becomes equal to or less than a set value within a predetermined time after the switch is turned on.

[0009]

According to the first means for solving the above problems, the present invention provides:
When an abnormality occurs in the rotation of the blower unit that controls the heat generation amount of the heating unit, the abnormality can be detected, and the energization of the heating unit can be stopped, so that the safety can be improved. Furthermore, if the current value detected by the current detecting means is less than or equal to the set value, the operation of turning the opening / closing means off and then on is performed at least once, so that the opening / closing means will not operate due to momentary power failure or mechanical vibration. False detection when turned off can be prevented.

Further, according to the second problem solving means, the abnormality detecting means detects only when the number of rotations detected by the rotation detecting means is equal to or higher than a predetermined number of rotations, so that the number of rotations of the rotating drum or the motor is lowered. As a result, it is possible to prevent erroneous detection when the current of the heating means is reduced.

Further, according to the third problem solving means, the abnormality detecting means turns on the opening / closing means once at a predetermined time when the opening / closing means is turned off and then turned on again.
The inrush current of the heating means can be reduced and the safety can be improved. Furthermore, the abnormality detection means detects an abnormal state only when the output of the current detection means falls below the set value within a predetermined time after all the opening / closing means are turned on. It is possible to prevent erroneous detection when the opening / closing means is turned off due to various vibrations.

[0012]

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

As shown in the figure, a rotary drum 1 is for accommodating and drying an object to be dried (clothes), and hot air is circulated in the rotary drum 1 by a heat exchange type double-blade fan (blowing means) 2. The heat exchange type double-blade fan 2 circulates warm air in the rotary drum 1 and at the same time takes in air from the outside to cool the fan and dehumidify the circulating air in the rotary drum 1. P
The TC heater (heating means) 3 is arranged in the air blowing path to the rotary drum 1, that is, in the circulating air intake, and heats the circulating air. The filter 4 is provided in the ventilation path of the heat exchange type double-blade fan 2, that is, in the air outlet of the rotary drum 1. When the filter 4 is clogged with lint, etc., the amount of air blown decreases, the heating power of the PTC heater 3 decreases, and the drying time becomes longer and the drying efficiency also decreases.

The motor 5 rotationally drives the rotary drum 1 and the heat exchange type double-blade fan 2. By controlling the rotation speed of the motor 5, the rotation speeds of the rotary drum 1 and the heat exchange double-blade fan 2 can be controlled. , The amount of heat generated by the PTC heater 3 can be controlled, and the current can be controlled. The temperature detecting means 6 comprises a first temperature detecting means 6a and a second temperature detecting means 6b. The first temperature detecting means 6a detects the exhaust gas temperature according to the temperature inside the rotary drum 1. Attached to the exhaust port of the rotary drum 1, and the second temperature detecting means 6b is a PTC.
The temperature of the intake air of the heater 3 is detected. The rotation detecting means 7 detects the number of rotations of the rotary drum 1. Two to four magnets 8 are attached to the rotary drum 1, and a magnetic sensor (not shown) is fixed to the main body to rotate the rotary drum 1. Detect the number.

The rotation control means 9 controls the rotation speed of the motor 5. The power semiconductor element 10 such as a bidirectional thyristor connected in series to the motor 5 and the rotation detection means 7 output the rotation of the rotary drum 1. Rotation speed determination means 11 for determining the number of rotations, rotation speed setting means 12 for setting the rotation speed of the rotary drum 1, and rotation speed comparison means for comparing the output of the rotation speed determination means 11 and the output of the rotation speed setting means 12. 13, pulse width control means 14 for controlling the conduction time of the power semiconductor element 10 by the output of the rotation speed comparison means 13, and the motor 5
The low speed starting means (starting control means) 15 which sets the set rotation speed to a low value at the time of starting and energizes the motor 5 and then energizes the PTC heater 3 with a delay.

The difference between the rotation speed of the rotary drum 1 detected by the rotation detection means 7 and the set rotation speed from the rotation speed setting means 12 is compared by the rotation speed comparison means 13, and the pulse width control means 14 is used for the power semiconductor element 10. To control the motor 5
Control the rotation speed of. Phase control can be considered as the simplest conduction time control method. In the case of an inverter, not only the conduction time but also the frequency is controlled. By doing so, stable rotation control of the motor 5 and the rotary drum 1 can be performed. The low speed starting means 15 controls the rotation speed setting means 12 for a predetermined time (for example, 20 seconds) when the motor 5 is started, and the rotation speed of the rotating drum 1 during normal operation (for example, 45 rpm).
The rotation speed is set to a low value (for example, 36 rpm), and a delay time for energizing the PTC heater 3 after the motor 5 starts rotating is provided. Further, the rotation speed determination means 11
Alternatively, the rotation cycle of the rotary drum 1 may be determined from the output of the rotation detection means 7.

The current detecting means 16 is the current transformer 1.
7 and the current-voltage conversion circuit 18, detects the input current of the PTC heater 3, and outputs the output from the current comparison setting means 1.
Enter in 9. The current comparison setting means 19 compares the set current value of the PTC heater 3 with the output of the current detection means 16,
The output is input to the rotation speed setting means 12 to control the set rotation speed. Here, the set rotation speed set by the rotation speed setting means 12 is set so that the current of the PTC heater 3 does not exceed or fall below a predetermined current value.

The abnormality detecting means 20 is composed of a stopping means 21 and an informing means 22, inputs the output of the rotational speed discriminating means 11 and the output of the current detecting means 16, and inputs the rotational speed discriminating means 11 to the rotational speed discriminating means 11.
When the current detection means 16 detects the rotation abnormality of the blower means 2, the stop means 21 turns off the power semiconductor element 10 to turn off the motor 5 to stop the rotation of the rotary drum 1, and at the same time, the PTC heater 3 The relay (opening / closing means) 23 connected in series is turned off, and the notification means 22 notifies.

Here, the abnormality detecting means 20 performs the operation of turning off the relay 23 once and turning it on again at least once when the output of the current detecting means 16 becomes equal to or less than the set value when the PTC heater 3 is energized. After that, when the output of the current detecting means 16 becomes below the set value again, the abnormal state is detected.

Further, the PTC heater 3 is the PTC heater 3
The contacts 23a, 23b of the relay 23 are divided into a and 3b.
Are connected in series, and the abnormality detection means 20 turns on the contacts 23a and 23b of the relay 23 one by one at predetermined time intervals, and detects the current within a predetermined time after all the contact points 23a and 23b are turned on. An abnormal state is detected when the output of the means 16 becomes equal to or less than the set value.
Incidentally, 24 is an AC power supply, and 25 is a power switch.

The operation of the above configuration will be described with reference to FIGS. 3 to 6. FIG. 3 is an operation flowchart of one embodiment of the present invention. In step 30, the power switch 25 is turned on to start the operation, and then step After initial setting in 31, the motor 5 is turned on in step 32, and the process proceeds to step 33. Step 33 is a subroutine for controlling the rotation speed of the rotary drum 1 at a constant low speed, and the step 33 is executed until 20 seconds have elapsed in step 34. Low speed starting means 15
To set the rotation speed of the rotation speed setting means 12 to a low speed (36 r
pm) and the rotation speed of the rotating drum 1 detected by the rotation detection means 7 and the set rotation speed from the rotation speed setting means 12 are compared by the rotation speed comparison means 13, and the pulse width control means 14 is used to control the power semiconductor. The element 10 is controlled to control the rotation speed of the motor 5 to a low speed. Therefore, the rotary drum 1
The amount of air circulated to the PTC heater 3 is small, and the inrush current flowing through the PTC heater 3 can be suppressed to be small.

Next, in step 35, the contact point 23a of the relay 23 is turned on, the PTC heater 3a is turned on, and the process proceeds to step 36 to delay for 30 seconds. Next, step 3
7, the contact point 23b of the relay 23 is closed, and the PTC heater 3a is turned on 30 seconds after the PTC heater 3a is turned on.
Is turned on and the process proceeds to step 38, and is delayed for 30 seconds again.

In step 39, it is detected whether or not there is any abnormality in the heat exchange type double-blade fan 2, that is, whether or not the fan belt is broken. The details of the operation at this time will be described with reference to FIG. 4. In step 50, it is determined whether the rotation speed of the rotary drum 1 is lower than a set value (30 rpm), and if it is less than the set value, the process proceeds to the next step. This is due to some reason
This is to prevent erroneous detection when the number of rotations is decreased and the current flowing through the PTC heater 3 is decreased. Step 5
If it is 0 and the rotation speed of the rotary drum 1 is higher than the set value (30 rpm), the routine proceeds to step 51, where it is judged whether the current of the PTC heater 3 is smaller than the set value Is. If the current of the PTC heater 3 is larger than the set value Is, the process proceeds to the next step. If less than the set value Is, step 52
Proceed to step 5, turn off the PTC heaters 3a and 3b, and step 5
Delay 3 for 1.5 seconds.

From step 54 to step 56, P
20 seconds after the TC heater 3a is turned on, the PTC heater 3b is turned on. Then, in step 57, timer 1
Is cleared, and in steps 58 and 59, it is determined again whether the current of the PTC heater 3 is smaller than the set value Is until the timer 1 has elapsed for 60 seconds. If it does not fall below the set value Is within 60 seconds, proceed to the next step. If the value is less than the set value Is within 60 seconds, the process proceeds to step 60, the fan belt shortage abnormality is detected and the abnormality is notified by the notifying means 22, the PTC heater 3 is turned off in step 61, and the motor 5 is turned on in step 62. Turn off.

Next, if there is no abnormality in the heat exchange type double-blade fan 2 in step 39 in FIG. 3, the rotation speed of the rotary drum 1 is controlled to a normal rotation speed (for example, 45 rpm) in steps 40 and 41. Then, in step 42, it is determined whether or not the drying is completed, and if it is completed, the drying operation is completed in step 43. If not completed, the process returns to step 39.

The details of the operation in steps 40 and 41 will now be described with reference to FIG. 5. In step 70, a one second timer is set, in step 71 the current detecting means 16 detects the current, and then in step 71. At 72, the current comparison setting means 19 calculates an error from the current setting value.
This calculation result is input to the rotation speed setting means 12, and in step 73, the rotation cycle of the rotary drum 1 is calculated and set according to the calculation result. Then, the cycle Ts calculated and set in step 74
Is compared with the maximum period Tsmax, and the period Ts is the maximum period Tsmax.
If it is larger, the process proceeds to step 75 and the maximum period Tsmax
Is the set cycle. When the cycle Ts is smaller than the maximum cycle Tsmax, the routine proceeds to step 76, where the calculated cycle Ts is compared with the minimum cycle Tsmin. Proceed to step 78. If the period Ts is larger than the minimum period Tsmin, the process proceeds to step 78. Therefore, the setting cycle T set by the rotation speed setting means 12
s is set smaller than the maximum period Tsmax and larger than the minimum period Tsmin.

In step 78, it is determined whether or not the rotation detection signal is input from the rotation detection means 7. If the rotation detection signal is input, in step 79 the rotation cycle T
Is detected and the process proceeds to step 80. In step 80, the rotation speed comparison means 13 detects an error from the set cycle Ts and proceeds to step 81. It is determined whether the detected error is within the set range, and if it is within the set range, the process proceeds to the next step. If the detected error is not within the set range, the routine proceeds to step 82, where the pulse width control means 14 calculates and sets the control phase, and the rotation speed of the rotary drum 1 is controlled to the rotation speed set by the rotation speed setting means 12. Then proceed to the next step. Step 78
Then, if the rotation detection signal is not input from the rotation detection means 7, the process proceeds to the next step.

FIGS. 6A to 6E are time charts showing the operation contents shown in the flow chart of FIG. The operation is started at time t0, the motor 5 is turned on, the PTC heater 3a is turned on at time t1 after the delay time, and the time t2 is reached.
Then, the PTC heater 3b is turned on. During this time, the rotating drum 1
The rotation speed of is constant at low rotation (36 rpm). Heater 3
When b is turned on and the delay time is followed by time t3, the current of the PTC heater 3 is detected to control the rotation speed of the rotary drum 1 or the heat exchange type double-blade fan 2 to control the power of the PTC heater 3 at a constant level.

In the above embodiment, the case where the rotary drum 1 and the heat exchanging type double-blade fan 2 are driven by the single motor 5 is shown, but the same effect can be obtained by using two motors each. is there. The same applies when the number of rotations of the motor 5 is detected.

[0030]

As is apparent from the above embodiments, according to the present invention, a rotating drum for drying clothes, an air blowing means for circulating warm air into the rotating drum, and an air blowing path into the rotating drum. A heating means provided in the motor, a motor for rotating the air blowing means or the rotary drum, an opening / closing means for controlling the heating means, a current detecting means for detecting a current of the heating means, and a power supply for the heating means. When the output of the current detecting means is less than or equal to the set value, after the operation of turning off the opening / closing means and turning it on again at least once, and then the output of the current detecting means is again less than or equal to the set value. Since an abnormality detecting means for detecting an abnormal state is provided, when an abnormality occurs in the rotation of the blower means for controlling the heat generation amount of the heating means, the abnormality is detected and the power supply to the heating means is stopped. It can be, it is possible to improve the safety. Furthermore, if the current value detected by the current detecting means is less than or equal to the set value, the operation of turning the opening / closing means off and then on is performed at least once, so that the opening / closing means will not operate due to momentary power failure or mechanical vibration. False detection when turned off can be prevented.

Further, a rotation detecting means for detecting the number of rotations or a rotation cycle of the rotating drum or the motor is provided, and the abnormality detecting means is in an abnormal state when the number of rotations detected by the rotation detecting means is a predetermined number of rotations or more. Therefore, it is possible to prevent erroneous detection when the current of the heating means is decreased due to the decrease in the rotation speed of the rotary drum or the motor.

Further, the heating means and the opening / closing means are each divided into a plurality of parts, and the abnormality detecting means turns on the opening / closing means one by one every predetermined time, and within a predetermined time after all the opening / closing means are turned on. Since the abnormal state is detected when the output of the current detecting means becomes less than the set value, when the opening / closing means is turned off and then turned on again, the switching means is turned on one by one every predetermined time. Inrush current can be reduced and safety can be improved. Further, the abnormality detecting means detects the abnormal state only when the output of the current detecting means becomes equal to or less than the set value within a predetermined time after all the opening / closing means are turned on. It is possible to prevent erroneous detection when the opening / closing means is turned off due to a power failure or mechanical vibration.

[Brief description of drawings]

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

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

FIG. 3 is an operation flowchart of the clothes dryer.

FIG. 4 is a subroutine flowchart of abnormality detection of the clothes dryer.

FIG. 5 is a flowchart of a subroutine for controlling the rotation speed of the clothes dryer.

FIG. 6A is an operation time chart when the clothes dryer starts operation. FIG. 6B is an operation time chart when the clothes dryer starts operation. FIG. 6C is an operation time chart when the clothes dryer starts operation. d) Operation time chart when the clothes dryer starts operation (e) Operation time chart when the clothes dryer starts operation

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating drum 2 heat exchange type double-blade fan (blowing means) 3 PTC heater (heating means) 5 motor 16 current detection means 20 abnormality detection means 23 relay (opening / closing means)

Claims (3)

[Claims] 1. A rotary drum for drying clothes, a blower for circulating warm air into the rotary drum, a heating means provided in a blower path into the rotary drum, and the blower or the rotary drum. A motor that rotates, an opening / closing unit that controls the heating unit, a current detection unit that detects the current of the heating unit, and an output of the current detection unit when the heating unit is energized is below a set value, At least one operation for turning off the opening / closing means and then turning it on again
A clothes dryer comprising: an abnormality detection unit that detects an abnormal state when the output of the current detection unit becomes equal to or less than a set value after the rotation. 2. A rotation detecting means for detecting the number of rotations or a rotation cycle of a rotating drum or a motor, wherein the abnormality detecting means is in an abnormal state when the number of rotations detected by the rotation detecting means is a predetermined number of rotations or more. 2. The clothes dryer according to claim 1, wherein the clothes dryer is detected. 3. The heating means and the opening / closing means are each divided into a plurality of parts, and the abnormality detecting means turns on the opening / closing means one by one every predetermined time, and within a predetermined time after all the opening / closing means are turned on. 2. The clothes dryer according to claim 1, wherein an abnormal state is detected when the output of the current detection means is below a set value.