JP2001218722A - Dishwasher - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water from splashing to the outside even in the case that a door 3 is suddenly opened during washing or rinsing in a dishwasher provided with constitution that a commercial AC power source is connected to a pump motor for washing and water discharge even in a door open state. SOLUTION: A door opening/closing detection part 35 repeats 'H'/'L' in synchronism with a power supply frequency when a door switch 24 is in an ON state and continuously becomes 'H' when it is in an OFF state. A microcomputer 20 reads the detection signals with a prescribed time interval, parallelly performs the processing of detecting the omission of one 'L' pulse signal and the processing of detecting the continuation of 'H' for prescribed time, and at the time of judging that the door is open by the detected result of the former, turns off a semiconductor switch 30 and stops the pump motor 106. At the time of judging that the door is open by the detected result of the latter, the semiconductor switches 27-29 are turned OFF.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a dishwasher,
More specifically, it relates to operation control in a dishwasher.

[0002]

2. Description of the Related Art As a dishwasher, tap water is introduced into a washing cabinet and stored in a bottom portion thereof. Then, a pump is operated to suck the stored water and feed it to a nozzle. Is known that has a configuration in which the tableware is washed by washing the dishes stored in the washing cabinet. This type of dishwasher includes a washing impeller that is driven to rotate to feed water to a nozzle, and a drain impeller that is driven to rotate to discharge water at the bottom of the washing box to the outside of the machine. There is a configuration in which both impellers are driven by one pump motor. In this configuration, when the pump motor is driven to rotate in the forward direction, the cleaning or rinsing operation is performed by the action of the cleaning impeller, and when the pump motor is driven to rotate in the reverse direction, the drain operation is performed by the action of the drain impeller. Be executed. In the dishwasher, in addition to the pump motor, a heater for heating stored water, a blower motor for introducing outside air into the washing cabinet, and a water supply pipe for supplying water to the washing cabinet are provided. And a driving unit such as a supplied water valve.

For example, if the water supply valve fails and the water supply cannot be stopped, water may overflow from the washing chamber. To prevent this, a switch linked to the float for detecting an abnormal water level is provided in the washing chamber, and when this switch is turned on, the pump motor is rotated in the reverse direction even during washing or rinsing. It is desirable to switch to and control to forcibly drain water. Overflow due to an abnormality in the water supply valve may also occur when the power of the dishwasher is turned off or when the door is opened while the operation is stopped but the operation is stopped. To enable drainage even when the power switch is OFF or the door switch is OFF (door opened), the power switch and the door switch must be a heater,
A power supply is provided only in the power supply line of a drive unit such as a blower motor and a water supply valve, and is provided in a power supply line of a power supply circuit for supplying a DC current to a pump motor and a control circuit for driving the pump motor. The connection may be such that the switch and the door switch are not inserted.

[0004]

However, if the door is suddenly opened while the pump motor is being rotated for cleaning or rinsing operation, the operation of the pump motor must be stopped immediately before jetting from the nozzle. There is a possibility that the spilled water jumps out of the machine and hits the user. Therefore, in the conventional dishwasher, although the door switch is not inserted in the common power supply path of the pump motor (that is, the power supply path required for rotating in both the forward direction and the reverse direction), the pump motor is rotated in the forward direction. One of the door switches, which is a double switch, is inserted into the power supply path for driving in the direction of rotation in the direction, and when the door is opened, the power supply to the pump motor is stopped in conjunction with the door switch. is there. According to this configuration, when the door is open, the power supply path for driving the pump motor to rotate in the reverse direction is connected, so that the drain impeller can be driven, and the abnormal It does not hinder the measures at the water level.

[0005] However, the double switch as described above is considerably higher in cost than a normal single switch. Also, in a typical dishwasher configuration,
The door switch is mounted on the door frame or in the vicinity thereof, whereas the electric board on which the pump motor and the circuit for driving the pump motor are mounted is disposed at a position far away from the door, such as below the cleaning cabinet. Therefore, the double switch and the electric board must be connected by a long cable, and the cost of the cable and the like is added.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to drive a cleaning impeller and a drain impeller with a single pump motor, and to operate the pump even when the door is open. A dishwasher in which a power supply is connected to a motor, which reliably prevents water from being sprayed out of the machine even when a door is opened when a cleaning impeller is driven by a pump motor. It is an object of the present invention to provide a dishwasher which can be manufactured at a low cost.

[0007]

A first dishwasher according to the present invention, which has been made to solve the above problems, has a machine frame having an openable and closable door, and is provided inside the machine frame. A washing box capable of accommodating dishes and storing water at the bottom, a nozzle for washing dishes by spraying water, and being stored at the bottom of the washing box by rotating in the forward direction. A cleaning / draining pump including a pump motor for discharging water stored in the bottom of the cleaning chamber to the outside by rotating in the reverse direction while feeding water to the nozzle, and turning on / off in response to opening and closing of the door; A dishwasher having a door switch for turning off the pump motor and not including the door switch in a power supply path for rotationally driving the pump motor in the normal rotation direction; a) rotating the pump motor in the normal rotation direction; Driven B) ON / OFF detection means for outputting binary signals in two different states in response to ON / OFF of the door switch; Door open / close determining means for intermittently reading a signal from the / OFF detecting means at an appropriate interval and determining the open / closed state of the door based on the read signal; d) the semiconductor when the door is closed Control means for switching the semiconductor switch to a blocking state in response to the door open / close determination means determining that the door is open when the switch is in a conductive state, wherein the door open / close determination means comprises a door Is characterized by detecting a change in the state of a signal that occurs when the signal is released from a closed state based on one or a small number of read signals.

In a second dishwasher according to the present invention, in the first dishwasher, the door open / close determining means may detect a change in the state of a signal generated when the door is opened from a closed state.
A first determination process for detecting based on one to a small number of read signals and a second determination process for detecting based on a read signal having a greater number of times than the first determination process are performed in parallel. The control means switches at least the semiconductor switch to a blocking state when it is determined that the door has been opened by the first determination processing, and when it is determined that the door has been opened by the second determination processing, It is characterized in that the other electric circuits are brought into an operation stop state.

Here, the other electric circuits include, for example, a heater for heating the stored water, a blower motor for discharging air from the storage, a water supply valve, and the like.

In a third dishwasher according to the present invention, in the second dishwasher, an electromagnetic switching relay is inserted in series with the semiconductor switch, and the control means opens the door by the second determination process. When the determination is made, the electromagnetic switching relay is set to the blocking state.

In a fourth dishwasher according to the present invention, in the third dishwasher, an energization detecting means for detecting energization of the pump motor is provided, the semiconductor switch is turned off, and the electromagnetic switching relay is turned on. It is characterized in that the semiconductor switch is inspected for a failure based on the result of the energization detecting means in the state.

A fifth dishwasher according to the present invention comprises
In a fourth dishwasher, the ON / OFF detecting means is at least an ON state or OFF of the door switch.
A pulse-like signal of a predetermined cycle is output for any one of the states, and the door open / close determination means reads the signal from the ON / OFF detection means intermittently at appropriate intervals not synchronized with the predetermined cycle. It is characterized by.

Further, a sixth dishwasher according to the present invention comprises:
In the fifth dishwasher, the door switch is turned off.
When the door switch is ON, the predetermined DC voltage and the approximate ground potential are maintained at a cycle synchronized with the frequency of the commercial AC power supply when the door switch is ON. A pulse-like signal that alternates and repeats is generated, and the door opening / closing determining means detects that the door has opened by detecting that the read signal has not reached the time when it should be approximately the ground potential or the predetermined DC voltage. It is characterized by detecting.

[0014]

According to the first and second dishwashers of the present invention, when the door is opened during the washing or rinsing operation, the door switch is turned on in accordance with the opening operation. To the OFF state. The door open / close determining means intermittently reads a signal from the ON / OFF detecting means. If noise from the outside coincides with the timing at which the signal from the ON / OFF detecting means is read by the door open / close determining means, the read signal is the ON / OFF of the door switch.
OFF is not accurately reflected. Therefore, when the opening / closing of the door is determined based on one or a small number of read signals, for example, it may be erroneously detected that the door is open despite the fact that the door is closed. On the other hand, it is possible to detect a change in the state of the signal that occurs when the door is opened from the closed state in a very short time. Therefore, the control means
In this way, priority is given to a small time delay until a detection result is obtained, and when the door is detected to be opened based on one or a small number of read signals, the power supply to the pump motor is prevented. Controls semiconductor switches. As a result, the rotation speed of the pump motor rapidly decreases, the pressure of the water pumped from the washing / draining pump to the nozzle drops, and the momentum of the water jet from the nozzle is lost. Thus,
ADVANTAGE OF THE INVENTION According to the dishwasher which concerns on this invention, it can prevent reliably that the water injected from the nozzle immediately after opening the door is scattered outside the machine.

The first and second dishwashers do not include a door switch in a common power supply path for rotating the pump motor in the forward rotation direction and the reverse rotation direction. If the second semiconductor switch is inserted into the power supply path for rotationally driving in the reverse direction, even if the door switch is in the OFF state, the second semiconductor switch is brought into the conductive state to perform cleaning and cleaning. The drain pump can function as a drain pump. Therefore, even when the water supply to the cleaning chamber cannot be stopped due to a failure of the water supply valve, for example, the abnormal water level in the cleaning chamber is detected and the control is performed such that the second semiconductor switch is brought into the conductive state. The water inside can be drained outside the machine.

Further, according to the second dishwasher of the present invention, it is determined that the door has been opened more reliably for an electric circuit which does not need to be stopped immediately even if the door is suddenly opened. The stop or continuation of the operation is controlled based on the possible result. Therefore, the ON /
When a gate-controlled semiconductor switch is used for the OFF control, the semiconductor switch is turned on uselessly.
/ OFF is not performed, and the life can be extended.

Further, according to the third dishwasher of the present invention, even if the semiconductor switch disposed in the power supply path for driving the pump motor to rotate in the normal rotation direction fails and is short-circuited, When the door is opened, the electromagnetic opening / closing relay is in a blocking state and the power supply to the pump motor is cut off, so that the injection of water from the nozzle can be reliably stopped.

According to the fourth dishwasher of the present invention,
By checking whether the pump motor is energized while the semiconductor switch is in the blocking state and the electromagnetic switching relay is controlled to be in the conducting state, it is possible to determine whether the semiconductor switch has failed and is in the short-circuit state as described above. Can be inspected. Therefore, when the semiconductor switch is determined to be faulty as a result of the inspection, the user is alerted, for example, by performing an abnormality notification, and an appropriate action such as a request for repair of the fault can be promptly performed.

In the fifth dishwasher according to the present invention, the signal from the ON / OFF detecting means is a pulse signal having a predetermined cycle for at least one of the ON state and the OFF state of the door switch. Since the predetermined period and the reading period by the door opening / closing determination unit are not synchronized, for example, the reading timing coincides with or is very close to the rising or falling of the pulse signal, and the read signal is a signal of the door switch. ON / OFF may not be accurately reflected. Therefore, the first
In the determination process of the above, it may be erroneously determined that the door has been opened even though the door has not been opened, but in the second determination process, such erroneous determination hardly occurs,
The semiconductor switch is not turned ON / OFF unnecessarily.

Further, in the sixth dishwasher according to the present invention, the signal obtained by the ON / OFF detecting means when the door is opened is synchronized with the frequency of the commercial AC power supply from a predetermined DC voltage or substantially ground potential. Since the signal changes to a cycle, the opening of the door can be detected with a very short time delay of about one cycle of the commercial AC power supply from the time when the door is opened. Therefore, according to this configuration, the injection of water from the nozzle can be stopped or weakened very quickly.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A dishwasher according to a first embodiment of the present invention (hereinafter referred to as "embodiment 1") will be described below with reference to FIGS.

FIG. 1 is a side sectional view showing the entire structure of the dishwasher according to the first embodiment. A washing cabinet 2 also serving as a drying chamber is disposed inside the machine casing 1, and a door 3 whose lower end is pivotally supported is provided at the front opening of the washing cabinet 2 in the forward direction (the direction of arrow P in FIG. 1). ). A rotatable arm 4 having a plurality of nozzles 5 formed on the upper surface is provided at the center of the bottom of the washing chamber 2. In addition, a water tank 6 is provided in communication with the bottom of the washing box 2, and a circulation port 7 and a drain port 8 are provided on the side of the water tank 6. Further, on the upper surface of the water storage tank 6, a mesh-shaped filter 9 for collecting residual vegetables flowing down from tableware is provided detachably.

A water supply port 13 is provided at the rear of the cleaning chamber 2. When the water supply valve 12 is opened, water supplied from an external tap, not shown, enters the cleaning chamber 2 through the water supply port 13. Be poured. Also, behind the washing box 2 is a washing box 2
A water level detection chamber 14 having a float (not shown) for detecting a water level in the inside is arranged, and water in the washing chamber 2 flows into the water level detection chamber 14 through a communication port (not shown) to perform washing and rinsing. For normal water level and abnormal water level when an excessive amount of water is stored. At the bottom of the washing box 2, a loop-shaped heater for making a large orbit around the rotation axis of the arm 4 to warm the water stored in the washing box 2 and to heat the air in the washing box 2 during drying. 15 are provided.

A washing and drainage pump 10 is arranged below the bottom of the washing box 2. The washing and drainage pump 10 is the first
A housing 103 in which a pump chamber 101 and a second pump chamber 102 are partitioned by a partition, a cleaning impeller 104 rotatably provided in the first pump chamber 101, and a rotation in the second pump chamber 102 Freely provided drainage impeller 1
05 and a pump motor 106 for driving the two impellers 104 and 105 coaxially. The first pump chamber 101 communicates with the circulation port 7 and the arm 4 and the second pump chamber 1
Numeral 02 communicates with the drain port 8 and the drain hose 11. At the time of washing and rinsing, the pump motor 106 is driven to rotate in the forward direction, thereby rotating the washing impeller 104.
Sends out the water sucked from the water tank 6 through the circulation port 7 to the arm 4. On the other hand, the pump motor 10
6 is driven to rotate in the reverse direction, whereby the rotating drain impeller 105 discharges the water sucked from the water storage tank 6 through the drain port 8 to the outside of the machine through the drain hose 11.

A blower 16 driven by a blower motor 17 is provided at the rear of the washing chamber 2. When the blower 16 is rotated, air is sucked from an air inlet 18 formed on the rear surface of the machine frame 1. The outside air is introduced into the cleaning chamber 2. Further, the humid air in the cleaning chamber 2 is discharged to the outside of the machine through an exhaust port 19 provided at an upper portion of the door 3.

As described above, the washing and drainage pump 10
In the embodiment, the cleaning operation or the draining operation is selectively performed by rotating the pump motor 106 in either the forward direction or the reverse direction.
06 is separately referred to as the cleaning pump motor 106a and the drainage pump motor 106b.
When the pump 6a is turned on, the pump motor 106 is driven to perform the cleaning operation. When the drain pump motor 106b is turned on, the pump motor 106 is driven to perform the drain operation. Naturally, the washing pump motor 1
06a and the drain pump motor 106b cannot be turned on at the same time.

In the dishwasher of this embodiment, when the operation is started, a washing step, a rinsing step and a drying step are sequentially performed. First, this operation will be schematically described. The user stores the dishes in a dish basket (not shown), opens the door 3, and places the dish basket inside the washing cabinet 2. When an operation start is instructed by a predetermined operation, first, a washing step is executed. Specifically, the water supply valve 12 is opened, and a predetermined amount of water up to a normal water level is stored at the bottom of the washing chamber 2. After the water supply is completed, the washing pump motor 106a is turned on, whereby the washing and draining pump 10 sucks water from the circulation port 7 of the water storage tank 6 and sends it to the arm 4 by pressure. The water rushes out of the small-diameter nozzle 5 and the arm 4 rotates by the reaction of the jet of water. The jetted water hits the tableware and flows down to the bottom of the washing cabinet 2, where solids are removed by the filter 9 and circulated to the water storage tank 6. Further, during this washing operation, the heater 15 is also turned on, and the stored water is heated by the heater 15.

When the water temperature reaches a predetermined temperature or when a predetermined washing operation time ends, the washing operation is ended, the washing pump motor 106a is turned off, and the drain pump motor 106b is turned on instead. As a result, the cleaning and drainage pump 10 discharges the water sucked from the drainage port 8 of the water storage tank 6 to the drainage hose 11. When drainage is completed, a rinsing process is then performed. Specifically, the water supply valve 12 is opened in the same manner as in the washing step, and clean water is newly introduced into the washing chamber 2. At this time, the heater 15 is not operated, but the water introduced into the cleaning chamber 2 by the residual heat becomes hot water. Then, the washing pump motor 106a is turned on in the same manner as in the washing operation, and the rinsing operation is performed for about one minute. Thereafter, the water in the washing chamber 2 is discharged. For example,
Such rinsing is repeated three times.

Thereafter, a high-temperature rinsing step is performed as the final rinsing. Specifically, the water supply valve 12 is opened and clean water is newly introduced into the cleaning chamber 2 as in the above-described washing step and rinsing step. After the water supply ends, wash pump motor 1
06a and the heater 15 are turned on, and the heated water is injected from the nozzle 5. The temperature of the water increases with the continuation of the operation. For example, when the water temperature reaches a predetermined temperature, the high-temperature rinsing operation is terminated. By performing the final rinsing step using hot water in this way, the dishes can be sterilized, and the dishes can be warmed, so that quick drying can be performed during the next drying step. When the high-temperature rinsing is completed, the water remaining at the bottom of the washing box 2 is discharged, the outside air is sent into the washing box 2 by rotating the blower 16, and the air is heated by the heater 15 to dry the dishes.

FIG. 2 is an electrical configuration diagram of a main part of the dishwasher of the present embodiment. A commercial AC power supply 22 connected via an external power supply outlet or the like is connected to one terminal of a power switch 23, a pump motor 106, and a primary winding of a transformer 25. The secondary winding of the transformer 25 is connected to a power supply circuit 26, and the power supply circuit 26 outputs a DC voltage Vd of, for example, +5 V necessary for the electric circuit. The other terminal of the power switch 23 is a door switch 24
, And the other terminal of the door switch 24 includes a heater 15, a blower motor 17, and a water supply valve 1.
2 are connected. Therefore, only when both the power switch 23 and the door switch 24 are turned on, the heater 15,
The commercial AC power supply 2 is connected to the blower motor 17 and the water supply valve 12.
2 are connected.

A microcomputer (hereinafter referred to as "microcomputer")
20) includes a CPU, a ROM, a RAM, a timer, and the like, and executes various controls such as a driving operation based on a control program stored in the ROM. A drive circuit 21 is connected to the microcomputer 20.
Gate control type semiconductor switch 2 via drive circuit 21
7, 28, 29, 30, 31 by applying a control voltage to the heater 15, the blower motor 17, and the water supply valve 1.
2. Washing pump motor 106a and drainage pump motor 1
06b is ON / OFF controlled. Power switch 2
In order to detect the open / close state of the power supply circuit 3, a power supply ON / O comprising a resistor R1, a diode D1, and an ON / OFF detection circuit 32
An FF detection unit 33 is provided, and a resistor R2, a diode D2, and an ON
A door open / close detection unit 35 including an / OFF detection circuit 34 is provided. Further, an abnormal water level detection switch 36 that is turned on / off in accordance with the vertical movement of the abnormal water level detection float 141 installed in the water level detection chamber 14 shown in FIG.

In the dishwasher of this embodiment, the pump motor 106 is connected to the commercial AC power supply 22 even when the power switch 23 is in the OFF state.
The drive circuit 21 is supplied with a drive current from the power supply circuit 26. Therefore, even if the power switch 23 is in the OFF state, the cleaning chamber 2 may be
When an abnormally large amount of water is introduced into the inside, the abnormal water level detection switch 36 is turned on by the rise of the abnormal water level detection float 141.
When the microcomputer 20 detects this, the microcomputer 20 applies a control voltage to the gate control type semiconductor switch 31 via the drive circuit 21 to turn on the drain pump motor 106b. As a result, the drain impeller 105 is driven to rotate, and the water stored in the cleaning chamber 2 is discharged outside the machine. In this way, it is possible to prevent the water level in the cleaning chamber 2 from rising further than the abnormal water level.

On the other hand, in the dishwasher of this embodiment, when the door switch 24 is turned off, the power supply path to the heater 15, the blower motor 17 and the water supply valve 12 is cut off, but the power supply path to the pump motor 106 is cut off. Not done.
If the user suddenly opens the door 3 during the washing and rinsing (including high-temperature rinsing) operation, the water jetted from the nozzle 5 may scatter outside unless the washing pump motor 106a is turned off immediately. is there. Therefore, in the dishwasher of the present embodiment, such scattering of water is prevented by the following control.

FIG. 3 is a flowchart showing a process of detecting the opening of the door 3 in the dishwasher. FIG.
(A) and (b) show the microcomputer 2 from the door open / close detector 35.
FIG. 7 is a waveform diagram showing an ON / OFF detection signal input to 0. When the door 3 is open and the door switch 24 is turned off, the ON / OFF detection signal continuously becomes “H” level as shown in FIG. 4B. On the other hand, the door 3 is closed and the door switch 24 is ON.
The frequency of the commercial AC power supply 22 (normally 5
"H" level and "L" in synchronization with 0Hz or 60Hz)
Repeat with the level alternately.

The microcomputer 20 reads such a signal at predetermined time intervals B, for example, as shown in FIG. 4C, and determines whether the signal is at the "H" level or the "L" level. (Step S1). This time interval B
Is shorter than a half cycle period of one cycle of the commercial AC power supply (that is, 0.02 seconds when the frequency is 50 Hz, and about 0.017 seconds when the frequency is 60 Hz) and 1 cycle.
It is set to a time longer than / 4 cycle. For example, when the frequency of the commercial AC power supply is 60 Hz, the time is set to 0.07 seconds.

The microcomputer 20 executes two types of door open / close determination processing in parallel based on the read detection signal.
In FIG. 3, steps SA1 to SA3 represent the second door opening / closing determination processing, and step SB1 represents the first door opening / closing determination processing.

In the second door opening / closing determination processing, first, every time a detection signal is read, if the signal is at the "H" level, the counter is counted up to count the detection signal at the "H" level (step SA1). . And 0.
It is determined whether three seconds have elapsed (step SA2),
If 0.3 seconds have elapsed, it is determined whether or not the count value for 0.3 seconds is equal to or greater than a predetermined value (step SA3). As shown in FIG. 4B, the door switch 2
When the switch 4 is OFF, the state of the "H" level continues, and therefore, in principle, all the detection signals within 0.3 seconds should be the "H" level. However, in practice, since the detection signal may be at the “L” level due to external noise or the like, the above-mentioned predetermined value is set to be 80 to 90% of the number of readings in the 0.3 second period. I just need.
When it is determined that the count value is equal to or more than the predetermined value, the microcomputer 20 applies a control voltage to the gate control type semiconductor switches 27, 28, and 29 to turn off the heater 15, the blower motor 17, and the water supply valve 12. (Step SA4).

In the first door open / close determination process, each time the detection signal is read, it is determined whether or not the "H" level has continued three times (step SB1). Now, A / 4 <B <A
As is clear from FIGS. 4A and 4C, when the door switch 24 is ON, the "H" level does not continue three times. On the other hand, door switch 2
When the switch 4 is OFF, the "H" level is repeated three times in principle. Therefore, when the "H" level continues three times, the microcomputer 20 applies a control voltage to the gate control type semiconductor switch 30 to turn off the cleaning pump motor 106a (step SB2). As a result, the pressure of the water that is pressure-fed from the cleaning / draining pump 10 to the arm 4 drops sharply, so that the injection of water from the nozzle 5 stops.

Since the detection timing of the detection signal by the microcomputer 20 is asynchronous with respect to the power supply frequency, for example, when the reading timing coincides with the switching point between the "H" level and the "L" level of the detection signal. In the case where the read timing is immediately after the switching of the detection signal and the signal is chattering, or when noise is externally mixed in accordance with the read timing, the “H” level of the detection signal is used. And the “L” level may not be accurately determined or may be erroneously determined.

According to the second door open / close determination processing, it is possible to eliminate such an accidental effect and to reliably detect that the door 3 has been opened. On the other hand, there is a time delay of about 0.3 seconds from when the door 3 is opened to when it is determined that the door 3 is opened. However, heater 1
5, the blower motor 17, and the water supply valve 12 shut off the power supply current when the door switch 24 is turned off. Therefore, after a time delay after the door 3 is opened, the gate-controlled semiconductor switches 27, 28, 29 are turned off. However, there is virtually no problem.

On the other hand, in the first door open / close determination processing,
Although the probability of erroneous determination due to the influence of chattering and noise as described above is higher than the second door opening / closing determination process, the time delay from when the door 3 is opened to when it is determined that the door 3 is opened is extremely short. Short. Therefore, when the door 3 is opened, the operation of the cleaning pump motor 106a can be quickly stopped, and the injection of water from the nozzle 5 can be stopped.

If the cleaning door motor 106a is turned off as a result of the first door opening / closing determination processing, and if the door 3 is determined not to be opened as a result of the second door opening / closing determination processing, Since it can be estimated that the determination by the first door opening / closing determination process is incorrect, the gate-controlled semiconductor switch 30 is controlled to be conductive at that time, and the cleaning pump motor 106a is turned on again. In this case, since the cleaning pump motor 106a is off for a short time, the delivery pressure of water is only reduced for a very short time, and has little effect on the washing performance and rinsing performance.

Considering only the operation, the heater 15,
Similar to the cleaning pump motor 106a, the blower motor 17 and the water supply valve 12 have almost no effect even if they are temporarily turned off due to erroneous door open / close determination. However, in the first door opening / closing determination process, the probability that the door 3 is erroneously determined to be opened even though the door 3 is not opened is increased, which means that the gate-controlled semiconductor switch is turned on. This means that the / OFF operation is frequently performed. Frequent ON / OFF operation may shorten the life of the gate-controlled semiconductor switch. Therefore, the ON / OFF operation of the gate-controlled semiconductor switch is not required unless it is necessary for safety such as ON / OFF of the cleaning pump motor 106a.
It is desirable to reduce the number of / OFF operations as much as possible.
In that sense, it is preferable to perform control using the determination result of the second door open / close determination process.

As described above, in the dishwasher according to the first embodiment, the ON / OFF detection signal of the door switch 24 is determined in parallel on the basis of two different determination criteria, so that a reliable door On the other hand, while the unnecessary ON / OFF operation of the gate-controlled semiconductor switch is suppressed by the opening detection, the injection of water from the nozzle 5 can be stopped within a short time after the door 3 is opened. Can be reliably prevented from flying out of the machine.

In the first embodiment, the door open / close detector 35
The ON / OFF detection signal input from the microcomputer 20 to the microcomputer 20 is a signal as shown in FIGS.
The signal is not limited to such a signal, and may be a signal in a different state corresponding to ON / OFF of the door switch 24. For example, when the door is open, the DC voltage V
Instead of d, it may be set to a substantially ground potential. Also,
When the door is closed, a pulse signal synchronized with the cycle of the commercial power supply may be used instead of a pulse signal which is substantially at a ground potential. Of course, in such a case, the timing of reading the signal by the microcomputer 20 and the method of determining whether the door is open or closed are appropriately changed.

Next, a dishwasher according to a second embodiment of the present invention (hereinafter referred to as "Example 2") will be described. FIG.
FIG. 7 is an electrical configuration diagram of a main part of a dishwasher according to a second embodiment. In this dishwasher, the connection between the pump motor 106 and the gate-controlled semiconductor switch 30 is connected to the microcomputer 2.
Only the point that the electromagnetic relay 37 whose ON / OFF is controlled by 0 is inserted is different from the configuration of the first embodiment shown in FIG. The microcomputer 20, as described above,
When it is determined that the door 3 has been opened by the door open / close determination processing, the gate control type semiconductor switch 30 is turned off. In addition, in the dishwasher according to the second embodiment, when the microcomputer 20 determines that the door 3 has been opened by the above-described second door open / close determination processing, the microcomputer 20 turns the electromagnetic relay 37 ON.
FF.

In the dishwasher of the first embodiment, when the gate-controlled semiconductor switch 30 fails and is short-circuited, the control by the microcomputer 20 does not function, and not only when the door 3 is opened, but also when the power switch 23 is opened. Even when it is turned off, the cleaning pump motor 106a continues to rotate. On the other hand, in the dishwasher of the second embodiment, the cleaning pump motor 106a can be stopped by turning off the electromagnetic relay 37.

Next, a dishwasher according to a third embodiment of the present invention (hereinafter referred to as "embodiment 3") will be described. FIG. 6 is an electrical configuration diagram of a main part of the dishwasher according to the third embodiment.
In this dishwasher, a pump motor conduction detection unit 39 including a resistor R3, a diode D3, and an ON / OFF detection circuit 38 is added to the configuration of the second embodiment shown in FIG.

In the dishwasher according to the second embodiment, it is not possible to detect that the gate-controlled semiconductor switch 30 has failed and short-circuited. However, in the dishwasher according to the third embodiment, the microcomputer 20 controls the electromagnetic relay 37 to operate. When the gate control type semiconductor switch 30 is turned on and the gate control type semiconductor switch 30 is turned off, the detection signal from the pump motor power supply detection unit 39 is read, and it is determined whether or not the power supply is cut off. Can be determined. That is, the electromagnetic relay 37 is turned on,
If the detection signal from the ON / OFF detection circuit 38 is maintained at substantially the potential Vd when the gate control type semiconductor switch 30 is OFF controlled, it is determined that the gate control type semiconductor switch 30 is short-circuited. If so, the microcomputer 20 concludes that the gate-controlled semiconductor switch 30 has failed. Then, an error is displayed on a display (not shown) or a buzzer sounds,
Notify the user that there is a problem.

The above embodiments are merely examples.
Obviously, changes and modifications can be made within the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a dishwasher according to a first embodiment of the present invention.

FIG. 2 is an electrical configuration diagram of a main part of the dishwasher according to the first embodiment.

FIG. 3 is a flowchart showing door open detection processing in the dishwasher according to the first embodiment.

FIG. 4 is a diagram showing an ON / OFF detection signal from a door open / close detection unit and a microcomputer read timing in the dishwasher according to the first embodiment.

FIG. 5 is an electrical configuration diagram of a main part of a dishwasher according to a second embodiment of the present invention.

FIG. 6 is an electrical configuration diagram of a main part of a dishwasher according to a third embodiment of the present invention.

[Explanation of symbols]

Reference numeral 2: Cleaning chamber 5: Nozzle 6: Reservoir 10: Cleaning / drain pump 101: First pump chamber 102: Second pump chamber 104: Cleaning impeller 105: Drain impeller 106: Pump motor 106a: Cleaning pump motor 106b Drain pump motor 11 Drain hose 12 Water supply valve 14 Water level detection chamber 141 Abnormal water level detection float 15 Heater 17 Blower motor 20 Microcomputer 21 Drive circuit 22 Commercial AC power supply 23 Power switch 24 Door switch 25 Transformer 26 Power supply circuit 27, 28, 29, 30, 31 Gate control type semiconductor switch 32, 34, 38 ON / OFF detection circuit 33 Power ON / OFF detection unit 35 Door open / close detection unit 36 Abnormal water level detection Switch 37: Electromagnetic relay 39: Pump motor conduction detection section

Claims (6)

[Claims] 1. A machine frame having an openable and closable door, a washing cabinet provided inside the machine frame and capable of storing tableware therein and storing water at a bottom portion, and spraying water. A nozzle for washing tableware and water stored at the bottom of the washing cabinet by rotating in the normal direction while pumping water stored in the bottom of the washing cabinet to the nozzle while rotating in the reverse direction. Cleaning / draining pump including a pump motor for discharging air out of the machine, and ON when the door is opened and closed
And a door switch for turning off the pump motor in a normal direction. The dishwasher does not include the door switch in a power supply path for rotating the pump motor in the normal direction. A semiconductor switch provided in a power supply path for rotational driving; b) ON / OFF detecting means for outputting binary signals in two different states corresponding to ON / OFF of the door switch; c) Door open / close determining means for intermittently reading a signal from the ON / OFF detecting means at appropriate intervals and determining the open / closed state of the door based on the read signal; d) when the door is closed When the semiconductor switch is in the conductive state, the control means for switching the semiconductor switch to the blocking state in response to the determination that the door is in the open state by the door open / close determining means. When, wherein the door closing determination means a state change of the signal that occurs when the door is opened from the closed state is characterized by detecting on the basis of one to a few times the read signal. 2. The dishwasher according to claim 1, wherein
The door opening / closing determining means detects a state change of a signal generated when the door is opened from a closed state based on one or a small number of read signals. A second determination process for detecting based on a read signal of a large number of times is performed in parallel, and the control unit determines at least the semiconductor switch when the first determination process determines that the door is opened. A dishwasher, wherein when the door is determined to be opened by the second determination processing, the other electric circuits are put into an operation stop state. 3. The dishwasher according to claim 2, wherein
Insert an electromagnetic switching relay in series with the semiconductor switch,
The dishwasher according to claim 1, wherein the control unit sets the electromagnetic switching relay to a blocking state when the second determination process determines that the door is opened. 4. The dishwasher according to claim 3, wherein
An energization detecting means for detecting the energization of the pump motor, based on a result of the energization detection means when the semiconductor switch is set to a blocking state and the electromagnetic switching relay is set to an energized state, based on a result of the failure of the semiconductor switch; A dishwasher characterized by inspecting a dishwasher. 5. The dishwasher according to claim 2, wherein the ON / OFF detecting means is configured to generate a pulse having a predetermined cycle with respect to at least one of an ON state and an OFF state of the door switch. A dishwasher, wherein the door opening / closing determining means reads the signal from the ON / OFF detecting means intermittently at appropriate intervals not synchronized with the predetermined cycle. 6. The dishwasher according to claim 5, wherein
When the door switch is OFF, a predetermined DC voltage or a substantially ground potential is maintained, and the door switch is turned ON.
In the state, the pulse signal is generated such that the predetermined DC voltage and the substantially ground potential are alternately repeated at a cycle synchronized with the frequency of the commercial AC power supply. A dishwasher characterized by detecting that a door has been opened by detecting that it has not reached a time when a predetermined DC voltage should have been reached at a substantially ground potential.