JP3264597B2 - Drum 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 drum type dryer capable of coping with a case where the control function of a control means is impaired.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show an electric circuit configuration for controlling a motor for driving a drum and a heater serving as a heat source of warm air in a conventional drum type dryer. First, a common part will be described with reference to FIGS.
It is connected to a commercial AC power supply 7 of 00V. The AC power supply 7 is connected to a DC power supply unit 8 that reduces the voltage of the AC power supply 7 and converts the voltage to DC. The DC voltage of the DC power supply 9 is applied to the microcomputer 9 and the drive circuit 10. You. Based on a control signal from the microcomputer 9, the drive circuit 10 cuts off the power to the excitation coils (not shown) of the relays 4 to 6 to open and close the relay switches 4a to 6a.

[0003] Drum dryers are usually designed so that the drying operation is performed with the door for opening and closing the entrance of the material to be dried closed. For this purpose, in FIG. 7, the door switch 1 which is turned on when the door is closed
The microcomputer 9 is configured so that one ON signal is given to the microcomputer 9. The microcomputer 9 detects that the door has been closed by inputting an ON signal from the door switch 11, and the motor 1 via the drive circuit 10.
And the heaters 2 and 3 are controlled. In FIG. 8, the door switch 11 is provided in the energizing path of the motor 1 and the heaters 2 and 3, and when the door is closed, the door switch 11 is closed.
Is turned on and the heater 1 and the heaters 2 and 3 can be energized.

[0004]

However, in the configuration shown in FIG. 7, when the microcomputer 9 goes out of control, the motor 1 and the heaters 2 and 3 can be turned off unless the power plug is pulled out from the outlet. It may be gone. In the configuration of FIG. 8, when the microcomputer 9 runs away, the door is opened and the door switch 11 is turned off, so that the motor 1 is turned off.
And the heaters 2 and 3 can be turned off.
Since a large current, which is the sum of the currents flowing through the motor 1 and the heaters 2 and 3, flows through the door switch 11, the life of the door switch 11, which is often constituted by a relatively small switch, may be shortened. Tracking may occur at the terminal.

The present invention has been made in view of the above circumstances, and has as its object to solve the problem when the control function of the control means is impaired.
An object of the present invention is to provide a drum type dryer capable of turning off a motor and a heater by a door switch, preventing a large current from flowing through the door switch, and extending the life of the door switch.

[0006]

According to a first aspect of the present invention, there is provided a drum-type dryer which supplies an AC power to a motor and a heater, and supplies hot air heated by the heater into the drum while rotating the drum by the motor. Opening and closing means for opening and closing an energizing path for supplying the AC power to the motor and the heater, a DC power supply unit for converting the AC power supply to DC, and a DC voltage of the DC power supply unit. Control means activated by applying a DC voltage of the DC power supply unit,
A drive unit that controls the opening and closing unit based on a control signal from the control unit, and a door switch that turns on and off in conjunction with a door that opens and closes the entrance to and from the object to be dried, wherein the DC voltage of the DC power supply unit is The present invention is characterized in that a current path applied to the driving means is opened and closed by the door switch.

The drum type dryer according to the present invention is characterized in that a power switch is connected in series with the door switch. In the drum type dryer according to the third aspect, the power switch is constituted by a relay switch of a relay, and a power operation switch is connected in parallel with the relay switch, and the control means determines that the power operation switch is operated. It is characterized in that it is configured to detect and energize the exciting coil of the relay switch to keep the relay switch in the ON state.

According to a fourth aspect of the present invention, when the operation switch for the power supply is operated and when the door switch is turned on in conjunction with the closing of the door, the detection of the DC voltage of the DC power supply unit is performed. Is converted into a voltage by the voltage conversion unit and supplied to the control unit. According to a fifth aspect of the present invention, in the drum type dryer, the electrode for detecting the object to be dried is provided facing the inside of the drum, and the opening / closing means is configured by a relay switch of a relay.

[0009]

According to the first aspect, when the door is opened,
The door switch cuts off the application of the DC voltage to the driving means. For this reason, the driving means is invalidated, and the opening / closing means opens the current supply path of the motor and the heater. Therefore, when the control function of the control means is impaired, for example, when the microcomputer runs out of control, the motor and the heater can be turned off by opening the door.

According to the second aspect of the present invention, since the drying operation is not performed unless the door is closed and the power switch is turned on, it is safer. According to the measure of claim 3,
The power operation switch can be constituted by, for example, a tact switch and provided on the operation panel in the same area as other operation switches.

According to the fourth aspect of the present invention, when the operation switch for the power supply is operated, and when the door switch is turned on due to the closing of the door, the voltage of the DC power supply unit is detected by the voltage conversion unit as a detection signal. And applied to the control means, it is possible to obtain a detection signal of a voltage suitable for application to the control means even if the DC voltage applied to the drive means is different from the DC voltage applied to the control means. .
According to the fifth aspect of the present invention, since the opening / closing means is constituted by the relay switch of the relay, there is no danger of electric shock even when touching the electrode for detecting the object to be dried.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 3 showing the overall configuration of a drum type dryer.
In the center of the front part of the outer box 21, an entrance 22 for taking in and out clothes to be dried is formed, and a door 23 for opening and closing the entrance 22 is pivotally provided. Further, a drum 24 for accommodating clothing put in through the entrance 22 is rotatably provided in the outer box 21. In this case, the front side of the drum 24 is supported by a support plate 25 attached to the front side of the outer box 21, and the rear side is attached to a casing 26 attached to the rear of the outer box 21 by a shaft 27.
Is supported through.

Further, a blower 28 is provided at a rear portion in the outer box 21. The blower 28 comprises the casing 26 and a double-winged fan 30 serving also as a heat exchanger, which is disposed inside the casing 26 so as to bisect the inside thereof back and forth, and is rotatably supported on a shaft 29. Have been. Inside the outer box 21, a duct 33 having heaters, for example, PTC heaters 31 and 32, is provided inside the front end so as to extend in the front-rear direction. The rear end of the duct 33 is in front of the casing 26. The front end communicates with the inside of the drum 24.

[0014] The drum 24 and the fan 30 are
The motor 1 is rotatably driven via belts 35 and 36 by a double-shaft motor 34 disposed at the rear of the motor 1. When the fan 30 rotates, the air in the drum 24 is sucked into the front side in the casing 26 through the filter 37 and the ventilation hole 38 formed in the rear surface of the drum 24, and then through the duct 33.
While being blown into the inside, outside air is sucked into the rear side inside the casing 26 from the suction hole 39 and is discharged to the outside through the exhaust hole 40.

On the other hand, an operation panel 41 is provided at the front of the outer box 21 below the door 23. Although not shown, the operation panel 41 is provided with a plurality of tact switches constituting a drying course selection switch, a start switch, and the like. The tact switch is a pressing portion 41a (see FIG. 2) formed on the front surface of the operation panel 41. ). Further, a door switch 42 is provided on the front back side of the outer box 11 so as to be located near the upper portion of the operation panel 41, and the door switch 42 is configured to be turned on by closing the door 23.

Further, a pair of electrodes 43 for detecting clothes (substance to be dried), for example, for detecting a degree of dryness, are provided below the support plate 25 so as to face the inside of the drum 24. This electrode 4
3, the clothing in the drum 24 is intermittently brought into contact with the rotation of the drum 24.
The resistance value between the three changes according to the moisture contained in the clothes, that is, according to the degree of drying of the clothes. From this, it is possible to detect the degree of dryness of the clothing by detecting the resistance value between the two electrodes 43.

In FIG. 1 showing the electrical control configuration, a pair of AC buses 45 and 46 are connected to a power plug 44 connected to an outlet (not shown) to which 100 V commercial AC power is supplied. I have. The motor 34 and the triac 4 are provided between the pair of AC buses 45 and 46.
7, PTC heaters 31 and triacs 48, and PTC heaters 32 and triacs 49 are connected in series with each other in series.
4. It functions as opening / closing means for opening / closing the current path of each of the PTC heaters 31 and 32.

A primary coil 52 of a step-down transformer 51 of a DC power supply unit 50 is connected between the pair of AC buses 45 and 46. The secondary coil 53 of the step-down transformer 51
Is connected to a rectifying / smoothing circuit 56 including a rectifying circuit 54 and a smoothing capacitor 55, and a plus-side DC power supply line 57 connected to a plus-side output terminal of the rectifying / smoothing circuit 56.
And the negative DC power supply line 5 connected to the negative terminal
8, a constant voltage circuit 59 is connected. In addition,
The positive DC power supply line 57 is connected to one of the pair of AC buses 45 and 46, for example, the AC bus 45, and the negative DC power supply line 58 is connected to a ground line.

The DC power supply section 50 functions as a DC power supply for a microcomputer 60 constituting control means. Among them, a constant DC voltage output from the constant voltage circuit 59 is applied to the microcomputer 60. Is done. The microcomputer 60 is activated by applying a DC voltage, and when a start switch (not shown) is operated, the microcomputer controls the triacs 47 to 49 via the drive circuit 61 in accordance with a preset drying program to execute the drying operation. Is configured. When the power plug 44 is connected to an AC power outlet (not shown), the DC voltage of the constant voltage circuit 59 is immediately applied to the microcomputer 60.

The pair of electrodes 43 are connected to the constant voltage circuit 5.
9 is connected to a dryness detection circuit 62 to which a DC voltage is applied.
The dryness of the clothes in the drum 24 is detected by the voltage between the three, and the dryness detection signal is supplied to the microcomputer 60. The microcomputer 60 is configured to stop the drying operation when it detects that the clothes have been dried based on the dryness detection signal from the dryness detection circuit 62.

The drive circuit 61 comprises three buffer circuits as drive means, for example, inverters 63 to 65. The input terminals of the inverters 63 to 65 are connected to the output port of the microcomputer 60, and the output terminals Are connected to the gates of the triacs 47 to 49. The inverters 63 to 65 are enabled when a DC voltage is applied, and are activated when a drive signal as a control signal is applied from the microcomputer 60.
The gate signal is given to the gate of 49, and the triac 47 ~
49 is turned on.

The DC voltage of the DC power supply unit 50 is applied to the inverters 63 to 65. For this purpose, one terminal of the drive circuit 61 is connected to a rectifying / smoothing circuit 56.
And the other terminal is connected to a ground line. Then, the driving circuit 61
The door switch 42 is connected to an energizing path connecting one terminal of the microcomputer and the positive DC power supply line 57, and a connection point between the door switch 42 and the drive circuit 61 is connected to an input port of the microcomputer 60. It is connected.

Next, the operation of the above configuration will be described. When the power plug 44 is connected to an outlet (not shown) of a 100 V commercial AC power supply, the AC power supply is stepped down to, for example, 5 V by the DC power supply unit 50 and converted to DC. Then, a DC voltage of 5 V, which has been made to have no voltage fluctuation by the constant voltage circuit 59, is applied to the microcomputer 60, thereby activating the microcomputer 60.

Now, in order to dry the clothes after washing, the door 2
3 is opened, clothes are put into the drum 24 from the entrance 22 and the door 23 is closed. By closing the door 23, the door switch 42 is turned on. When the door switch 42 is turned on, the DC voltage of the DC power supply unit 50 is supplied to the drive circuit 61 and the microcomputer 60
3 as a closing detection signal. After that, operate the drying course selection switch to select a desired drying course,
Operate the start switch.

When the start switch is operated, the microcomputer 60 causes the inverters 63 to 63 of the drive circuit 61 to operate.
A drive signal is given to 65, and inverters 63 to 65 give a gate signal to triacs 47 to 49 in response to the drive signal. As a result, the triacs 47 to 49 are turned on, the motor 34 is energized to rotate the drum 24 and the fan 30, and the PTC heaters 31 and 32 are rotated.
Is energized and generates heat. Then, the air in the drum 24 is filtered by the rotation of the fan 30 and the ventilation holes 38.
From the casing 26 to the front side in the casing 26,
, So that the clothes in the drum 24 are dried by being heated and heated by the PTC heaters 31 and 32 in this circulation process.
At the same time, the outside air is sucked into the rear part of the casing 26 from the suction hole 39 by the rotation of the fan 30 and is discharged from the discharge hole 40.
The warm air from the drum 24 sucked into the front side of 6 is cooled and dehumidified.

During the drying operation performed by supplying warm air into the drum 24 while rotating the drum 24, the microcomputer 60 detects the degree of drying of the clothes based on the drying degree detection signal from the drying degree detection circuit 62. are doing. When the drying of the clothes is completed, the microcomputer 6
0 stops output of the drive signal. Then, the inverter 6
Since the gates 3 to 65 stop outputting the gate signal, the triacs 47 to 49 are turned off. Thereby, the motor 34,
The PTC heaters 31 and 32 are turned off, and the drying operation ends as described above. Thereafter, the door 23 is opened to take out the clothes in the drum 24 from the entrance 22.

During the drying operation as described above, even if the microcomputer 60 runs away for some reason and the drying of the clothes is completed, the microcomputer 60
The drive signal is output from the motor 34, P
The TC heaters 31, 32 may remain energized. In such a case, the door 23 is opened. Then, the door switch 42 is turned off, and the DC power supply unit 50 and the drive circuit 6 are turned off.
1 is cut off, so that no DC voltage is applied to the drive circuit 61. As a result, even if the drive circuit 61 is invalidated and the drive signal is output from the microcomputer 60, the inverters 63 to 65 stop outputting the gate signal, so that the triacs 47 to 49 are turned off and the motor 34 and the PTC heater are turned off. 31 and 32 are cut off.

As described above, according to the present embodiment, the door switch 42 has a weak current for causing the microcomputer 60 to detect that the door switch 42 has been turned on.
Further, since only a weak current for enabling the drive circuit 61 flows, the life of the drive circuit 61 is prolonged, and there is no danger of tracking occurring at the terminal. Incidentally, it is generally known that tracking may occur between different poles to which an AC voltage of 100 V is applied, but will not occur if the DC voltage is 45 V or less and the current is 10 A or less.

Further, the door switch 42 is connected to the DC power supply 5
Since the drying operation can be stopped by opening the door 23 even if the microcomputer 60 runs out of control, the emergency operation can be promptly dealt with even when the microcomputer 60 runs out of control, since it is provided in the current path between the drive circuit 61 and the drive circuit 61. Can be improved.

FIG. 4 shows a second embodiment of the present invention.
Hereinafter, the same parts as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and only different parts will be described. A relay switch 67 of a relay 66 serving as a power switch is connected in series with the door switch 42 to the power supply path connecting the plus side DC power supply line 57 of the DC power supply section 50 and the drive circuit 61 to the DC power supply section. It is connected so as to be located on the 50 side. Then, the relay switch 67 and the door switch 4
One end of the exciting coil 68 of the relay 66 is connected to the common connection point of the two, and the other end of the exciting coil 68 is connected to the collector of the NPN transistor 69. The emitter of the transistor 69 is connected to the ground line, and the gate is connected to the output port of the microcomputer 60. In addition, a power supply operation switch 70 formed of, for example, a tact switch is connected in parallel with the relay switch 67. Then, the power supply operation switch 70
The tact switch constituting the drying course selection switch,
It is arranged on the operation panel 41 together with other tact switches constituting a start switch and the like so as to be located in the same area.

In the above configuration, the clothes after washing are put into the drum 24 and the door 23 is closed. Thereafter, when the power supply operation switch 70 is operated, the door switch 42 is already on due to the closing of the door 23.
The DC voltage of the DC power supply unit 50 is input to the microcomputer 60 as a signal for detecting the closing of the switch 3 and the turning-on of the power supply operation switch 70. Then, the microcomputer 60 supplies a gate signal to the transistor 69 to turn on the transistor 69. For this reason, the excitation coil 68 is energized to hold the relay switch 67 in the ON state. Therefore, although the power switch 70 automatically returns after operation and turns off, the relay switch 67 keeps the ON state (self-holding). The circuit 61 remains activated.

As described above, according to the present embodiment, since the relay switch 67 and the door switch 42 are connected in series to the current path for applying the DC voltage of the DC power supply unit 50 to the drive circuit 61, the power supply Relay switch 6
If the switch 7 is turned on and the door switch 42 is not turned on, the drying operation is not started, which is more secure. In addition, since a large current does not flow through the relay switch 67, its life can be extended.

Further, the power switch is constituted by the relay 66, and the relay switch 67 is turned on by operating the power operation switch 70, so that the power operation switch 70 is constituted by a tact switch and other tact switches are provided. Together with the switches, they can be arranged together in the same area of the operation panel. Therefore, when the power switch is configured by a push-button switch that repeats on / off for each pressing operation, the push-button switch is a drying course selection switch,
There is a restriction that it must be provided separately from the area where the tact switch constituting the start switch and the like is arranged. However, in this embodiment, the power supply operation switch 70 is used for selecting a drying course, starting, etc. Can be provided in the same area as the tact switch, and the design appearance can be improved.

FIGS. 5 and 6 show a third embodiment of the present invention. The same parts as those in FIG. 4 showing the second embodiment will be designated by the same reference numerals and only different parts will be described. In this embodiment, the opening / closing means for opening / closing the current path of the motor 34 and the PTC heaters 31 and 32 are relay switches 74 to 76 of the relays 71 to 73.
Reference numeral 76 is connected to a current path of the motor 34 and the PTC heaters 31 and 32.

On the other hand, the step-down transformer 51 of the DC power supply 50
Is provided with a secondary coil 77 separately from the secondary coil 53, and a rectifying and smoothing circuit 80 including a rectifying circuit 78 and a smoothing capacitor 79 is connected to the secondary coil 77. The rectifying / smoothing circuit 80 functions as a DC power supply of a driving circuit 81 as a driving means, a minus DC power supply line 82 is connected to a ground line, and a plus DC power supply line 83 is connected to a relay switch 67 and a power supply switch. Drive circuit 81 via door switch 42
It is connected to the. In this case, the microcomputer 6
The output voltage of the constant voltage circuit 59 on the side of the secondary coil 53 that functions as a DC power supply of 0 is set to 5 V, and the output of the rectifying and smoothing circuit 80 that is a DC output of the secondary coil 77 that is the DC power supply of the drive circuit 81. The voltage is set to 24V. In this embodiment, neither of the rectifying / smoothing circuits 56, 80 is connected to the AC buses 45, 46.

Then, in order to detect that the power operation switch 70 is turned on, the power operation switch 70 is turned on.
The common connection point between the relay switch 67 and the door switch 42 is connected to the input port of the microcomputer 60 via the voltage converter 84. Also, the relay switch 6
In order to detect that the door switch 42 and the door switch 42 are turned on, a common connection point between the door switch 42 and the drive circuit 81 is connected to the microcomputer 6 via the voltage converter 85.
0 is connected to the input port. This voltage converter 8
Reference numerals 4 and 85 each include, for example, a DC-DC converter.
Step down to V.

On the other hand, the drive circuit 81 is constituted by connecting a series circuit of the exciting coils 86 to 88 of the relays 71 to 73 and the switching circuits 89 to 91 in parallel between the door switch 42 and the ground line. I have. Here, since the switching circuits 89 to 91 have the same configuration, for example, only the switching circuit 89 will be described with reference to FIG. 6, and the description of the remaining switching circuits 90 and 91 will be omitted. That is, the switching circuit 89 includes a PNP transistor 92 and an NPN transistor 93. The base of the PNP transistor 92 is connected to the output port of the microcomputer 60, and the collector is the rectifying and smoothing circuit 56 having a DC output of 5V. Positive power supply line 5
7, and the emitter is connected to the base of the NPN transistor 93. And NPN
The collector of the transistor 93 is connected to the exciting coil 86 of the relay 71, and the emitter is connected to the ground line. A flywheel diode 94 is connected between the collector and the emitter of the NPN transistor 93.

In the drive circuit 81 having such a configuration, when a low-level drive signal is output from the microcomputer 60 to each of the switching circuits 89 to 91 in a state where the relay switch 67 and the door switch 42 are on, the PNP type is output. Since the transistor 92 is turned on and the DC output of the rectifying / smoothing circuit 56 is applied between the base and the emitter of the NPN transistor 93, the NPN transistor 93 is turned on, the exciting coils 86 to 88 are energized, and the relay switch 74 is turned on. To 76 are turned on. However,
Even if the microcomputer 60 outputs a low-level drive signal to each of the switching circuits 89 to 91 while the relay switch 67 or the door switch 42 is off, the NPN transistor 93 does not turn on. From the above, the drive circuit 81 is connected to the DC power supply unit 50.
When the DC voltage is not applied, it is in an invalid state, and when the DC voltage is applied, it is enabled.

As described above, the motor 34, the PTC heater 3
According to the present embodiment in which the current supply paths 1 and 32 are opened and closed by the relay switches 74 to 76, there is no risk of electric shock even if the dryness detection electrode 43 is touched. That is, in the first and second embodiments in which the energizing paths of the motor 34 and the PTC heaters 31 and 32 are opened and closed by the triacs 47 to 49, a voltage higher or lower than one main electrode of the triacs 47 to 49 is gated. If not applied as a signal, the triacs 47 to 49 do not turn on. Therefore,
One AC bus 45 and the positive DC power supply line 57 are connected so that they have the same potential, and the inverters 63 to 65 of the drive circuit 61 are connected to the positive DC power supply line 57 (one AC bus 45). A low voltage gate signal is applied to the gates of the triacs 47 to 49.

However, when the positive DC power supply line 57 is connected to one AC bus 45, the ground side of the AC power supply is connected to one AC bus 45 (plus DC power supply line 57) when the power plug 44 is inserted into the outlet. If the AC bus 45 is connected to the non-ground side, there is a risk of electric shock when the electrode 43 is touched. However, in this embodiment, the positive DC power line 57 and the negative DC power line 58 are connected to the AC bus 45.
Since there is no need to connect to any of the electrodes 43 and 46, there is no risk of electric shock even if the electrode 43 is touched.

In this embodiment, the relay switches 74 to
Since a relatively large current flows through the relay 71, the relay 71
~ 73 must be composed of a relatively large capacity,
For this reason, even if the voltage applied to the excitation coils 86 to 88 must be increased (for example, 24 V), the voltage is converted into a voltage (for example, 5 V) suitable for the microcomputer 60 by the voltage converters 84 and 85. And
It can be input as an ON signal of the power operation switch 70, the relay switch 67, and the door switch 42. Therefore, the rectifying / smoothing circuit 80, which is a DC power supply of the drive circuit 81, can be used as it is as a power supply for the ON signal of the power supply operation switch 70, the relay switch 67, and the door switch 42, and the configuration is simplified. As is well known, relays generally have a structure with excellent tracking resistance,
There is almost no risk of tracking.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be extended or modified as follows. The door switch 42, the relay switch 67 as a power switch, and the power operation switch 70 may be provided between the drive circuits 61 and 81 and the ground line. The drum 24 and the fan 30 may be driven by different motors. Fan 30, PTC heater 3
PTC heaters 31 and 3 constitute hot air generating means for generating hot air to be supplied to the drum 24.
Numeral 2 may be constituted by a heater made of a resistance heating wire such as a nichrome wire.

[0043]

According to the drum type dryer of the present invention, the current path for applying the DC voltage of the DC power supply to the drive means is opened and closed by the door switch, so that a large current flows through the door switch. Since there is no longer, the service life is extended, and when the door is opened, the application of DC voltage to the drive means is cut off by the door switch, the drive means is invalidated, and the opening and closing means opens the current paths of the motor and the heater.
Even if the control function of the control means is impaired, the motor and the heater can be turned off by opening the door.

According to the second aspect of the present invention, the power switch is connected in series with the door switch.
If the door is not closed and an operation for turning on the power switch is not performed, the drying operation is not performed, so that the power supply switch is safer.

According to a third aspect of the present invention, the power switch is constituted by a relay having an exciting coil and a relay switch, and a power operation switch is connected in parallel with the relay switch of the relay. When the operation switch for power supply is detected and the excitation coil of the relay switch is energized and the relay switch is held in the ON state, the operation switch for power supply is constituted by a tact switch, for example. Can be provided in the same area as the tact switches constituting the other operation switches, and the design can be excellent.

In the drum type dryer according to the fourth aspect, the control means includes a step of changing the DC voltage of the DC power supply unit when the operation switch is operated and when the door switch is turned on in conjunction with the opening and closing of the door. With the configuration in which the DC voltage converted by the converter is provided as a detection signal, when the power supply operation switch is operated, and when the door is closed, the voltage of the DC power supply unit is detected as the detection signal. Since the voltage is converted by the voltage conversion unit and applied to the control unit, even if the DC voltage applied to the drive unit and the DC voltage applied to the control unit are different, a detection signal of a voltage suitable for application to the control unit Can be obtained.

In the drum type dryer according to the fifth aspect, the pair of electrodes for detecting the object to be dried facing the inside of the drum are provided, and the opening / closing means is constituted by a relay having an exciting coil and a relay switch. There is no risk of electric shock even when touching the electrode for degree detection.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a front view of a drum dryer.

FIG. 3 is a longitudinal sectional side view partially cut away.

FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 1, showing a third embodiment of the present invention.

FIG. 6 is an electric circuit diagram showing a switching circuit.

FIG. 7 shows a conventional example and is equivalent to FIG.

FIG. 8 is a diagram corresponding to FIG. 1 showing another conventional example.

[Explanation of symbols]

21 is an outer box, 22 is an entrance, 23 is a door, 30 is a fan, 31 and 32 are PTC heaters, 34 is a motor, 41 is an operation panel, 42 is a door switch, 43 is an electrode, and 47 to 47.
49 is a triac (opening / closing means), 50 is a DC power supply unit,
60 is a microcomputer (control means), 61 is a drive circuit (drive means), 63 to 65 are inverters, 66 is a relay, 70 is a power supply operation switch, 71 to 73 are relays, and 74 to 76 are relay switches (open / close means). ).

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-327898 (JP, A) Patent 2902906 (JP, B2) JP-B-4-9440 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06F 58/28 D06F 58/02 H01H 13/18

Claims (5)

(57) [Claims] An AC power source is supplied to a motor and a heater, and while heating a drum by a motor, hot air heated by a heater is supplied into the drum to dry the object to be dried. Opening / closing means for opening / closing an energizing path to be supplied to the motor and the heater; a DC power supply unit for converting the AC power supply to DC; a control means enabled by applying a DC voltage of the DC power supply unit; A drive unit that is enabled by applying a DC voltage of a power supply unit and controls the opening / closing unit based on a control signal from the control unit; and a door switch that is turned on / off in conjunction with a door that opens and closes an entrance of a material to be dried. A drive path for applying the DC voltage of the DC power supply unit to the driving means, the door being opened and closed by the door switch. Dryer. 2. The drum type dryer according to claim 1, wherein a power switch is connected in series with the door switch. 3. A power supply switch comprising a relay switch of a relay, and a power supply operation switch connected in parallel with the relay switch. The control means detects that the power supply operation switch has been operated, and the relay switch 3. The drum-type dryer according to claim 2, wherein the excitation coil is energized to hold the relay switch in an ON state. 4. When an operation switch for a power supply is operated,
And, when the door switch is turned on in conjunction with the closing of the door, the DC voltage of the DC power supply unit is converted into a voltage by the voltage conversion unit and supplied to the control unit as a detection signal. The drum type dryer according to claim 3, wherein 5. The drum according to claim 1, wherein an electrode for detecting an object to be dried is provided facing the inside of the drum, and the opening / closing means is constituted by a relay switch of a relay. Dryer.