JPH05261057A - Tableware washing machine - Google Patents

Abstract

PURPOSE:To constitute the washing machine so that a motor lock detecting circuit is operated quickly, and also, the reoperation can be executed, even in the case any abnormality is generated under the considered use environmental condition by detecting a capacitor terminal voltage variation of a washing pump motor and detecting abnormality at the time of locking of a circulating pump. CONSTITUTION:When a washing pump motor 13 is locked by some abnormality, an AC voltage between terminals of a capacitor 30 connected in series to an auxiliary coil 29 of the washing pump motor 13 becomes lower than that of the time of normal rotation. The AC voltage between the terminals of this capacitor 30 is rectified by a rectifying circuit 31 and becomes a driving current of a light emission diode 33 in a photocoupler 32. Subsequently, even if a photodetecting side transistor 34 receives an optical signal being proportional to its driving current, its collector voltage is inputted to a pulse generating circuit 35. In this case, the number of pulses of the pulse generating circuit 35 increases or decreases in proportion to the collector voltage of the transistor 34. By fetching this number of pulses in a microcomputer 36, a lock state is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dishwasher, and more particularly to control of a dishwasher which is most suitable for detecting an abnormal state of a circulation pump.

[0002]

2. Description of the Related Art The function of a thermostat for an overheat protector is to detect an abnormal temperature and cut off the power supply to the heater in order to prevent equipment damage when an abnormal condition occurs and the heater unit is heated. At the same time, the user can be notified of an abnormal state based on the OFF signal, and the system can be automatically or manually restored by a bimetal method or the like so that it can be used again by releasing some abnormal state. Therefore, in an abnormal state, it must be possible to restart operation even if the overheat protector operates.

Conventionally, a fusing-type thermal fuse is directly installed in a heater unit made of a member having good thermal conductivity in which a sheathed heater is embedded in order to detect the stability of performance and the temperature of the heater at the time of abnormality. A fin made of a good thermal material having a mounting part is placed in close contact with a part of the sheathed heater embedded part of the heater unit, and is positioned inside the heater unit cover that serves as an air passage to fix the thermal fuse and also close contact with the fin. The thermostat was installed. The operating environment condition is, for example, that the outside air temperature is 0.
If the circulating pump locks during cleaning when the operating conditions are bad, at 110 ° C and 110% of the rated voltage, water does not splash on the upper heater and the upper heater heats abnormally and the thermostat detects an abnormal temperature. Although the power to the heater was cut off, the thermal inertia of the heater also melted the thermal fuse, which made it impossible to restart operation, which was not sufficient for reliability.

[0004]

SUMMARY OF THE INVENTION According to the present invention, the motor lock detection circuit operates quickly and can be restarted even if any abnormality occurs under the conceivable operating environment conditions. To provide an excellent dishwasher.

[0005]

According to the present invention, when an abnormality occurs in a circulation pump, a change in capacitor terminal voltage of a washing pump motor is detected, and control is performed so that the power is automatically turned off when the motor is locked. Can be achieved by

[0006]

[Operation] That is, when the circulation pump is locked during cleaning,
Before the thermostat reaches the operating temperature, the lock of the cleaning pump motor is detected through the motor lock detection circuit by the change of the capacitor terminal voltage of the cleaning pump motor.
It also acts to turn off the power supply before the thermal fuse reaches the fusing temperature.

[0007]

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

FIG. 1 is a vertical cross-sectional view showing the entire internal structure of a dishwasher according to the present invention, FIG. 2 is a motor lock detection circuit of the present invention, and FIG. 3 is a pulse due to a change in power supply voltage and ambient temperature. It shows the relationship of numbers.

In FIG. 1, reference numeral 1 denotes a dishwasher main body, which has a hinge 2 on the front surface as a center of rotation and a door 3 which can be opened and closed forward as indicated by an arrow. Inside the door 3, a controller 4 that controls the washing and drying cycle operations such as water supply, heating, hot water circulation, drainage, and air blowing of the dishwasher is installed, and above the door 3, the progress state and the controller. An indicator 5, etc., which is instructed by 4 and performs various displays, is installed. Door 3
The inner wall of the door has an inner wall 6 made of stainless steel,
Similarly, a cleaning tank / drying tank (hereinafter referred to as a cleaning tank) 7 formed of a stainless material is configured to be kept airtight from the outside by a packing 8 when the door 3 is closed. An upper rail 9 and a lower rail 10 are configured in the cleaning tank 7, and an upper basket 11 and a lower basket 12 are configured to be easily moved to the front of the main body 1. In addition, the lower surface of the cleaning tank 7 has a plurality of small holes 15a for receiving a water pressure from a circulation pump composed of the cleaning pump motor 13 and the cleaning pump 14 to obtain a rotational force, and at a substantially central portion thereof. A lower nozzle 18 having a jet 17 for introducing water to the upper nozzle 16 is rotatably attached. Water from the spout 17 passes through a water conduit 19 fixed to a substantially central portion of the lower basket 12 and is spouted from a small hole 15b of the upper nozzle 16, and the upper nozzle rotates by its reaction. A lower heater spherical heater unit 20 formed in a spherical shape on the lower surface of the cleaning tank 7 and an upper heater spherical heater unit 21 formed in a spherical surface on the side surface are installed to dry the lower heater spherical heater unit 20. The heater unit cover 22 is installed so as to provide a ventilation path for the cleaning tank 7 through the blower fan 23, the intake port 24, the heater unit cover 22 and the duct 25, and the ventilation port 26 provided on the rear surface of the cleaning tank 7.
It is configured to send warm air to. The outside means the exhaust port (1) 27a and the exhaust port (2) provided on the upper surface of the cleaning tank 7.
It is connected via 27b. A thermistor 28 is provided below the main body 1 to detect the outside air temperature.

In FIG. 2, the motor lock detection circuit rectifies the AC voltage between the terminals of the capacitor 30 connected in series with the auxiliary coil 29 of the washing pump motor 13 by the rectification circuit 31, and the light emitting diode in the photocoupler 32. 33 drive current. The light receiving side transistor 34 receives an optical signal proportional to the drive current, and the main transistor 34
The collector voltage of is input to the pulse generation circuit 35. The number of pulses of the pulse generation circuit 35 increases or decreases in proportion to the main collector voltage. The number of pulses is taken into the microcomputer 36.
The normal rotation state or lock state of the cleaning pump motor 13 is detected based on the number of the pulses. By the way, since the number of pulses in the normal rotation state and the locked state of the cleaning pump motor 13 differs depending on the environmental conditions (ambient temperature, power supply voltage, etc.), the cleaning pump motor 13 determined by the fluctuation of the power supply voltage and the fluctuation of the ambient temperature in FIG. The microcomputer 36 stores the intermediate value between the minimum pulse number in the normal rotation state and the maximum pulse number in the locked state. The ambient temperature is detected by the thermistor 28, the number of pulses of the reference value due to the ambient temperature is determined by the microcomputer 36, and it is matched with the number of pulses from the motor lock detection circuit. The microcomputer 36 determines the number of pulses as a motor lock state and detects the motor rotation state.

Next, the washing operation of the dishwasher will be described. The tableware is installed in the upper basket 11 and the lower basket 12, the detergent is put into the detergent inlet (not shown), the door 3 is closed, and the operation is started by the operation button. When the water is supplied up to the specified water level, the lower heater spherical heater unit 120 and the upper heater spherical heater unit 21 are energized, and at the same time, the cleaning pump motor 13 is operated. Pressurized water is the lower nozzle 18
And, at the same time as being jetted from the small hole 15a of the upper nozzle 16, it receives the reaction force of the jetting and starts to rotate. The number of revolutions is about 20 revolutions per minute, and the washing water evenly hits the dishes in the washing tank 7 and the upper heater spherical heater unit 21, and the water temperature gradually rises. The action cleans the dishes. The cleaning is completed about 15 minutes after the start of the operation, and the rotation of the cleaning pump motor 13 is stopped. In this cleaning operation, the cleaning pump motor 13
Is locked due to some abnormality, the capacitor voltage becomes lower than the normal rotation state, and as a result, the pulse generation circuit 35
The number of pulses of is reduced. By this phenomenon, the normal rotation state or the locked state of the cleaning pump motor 13 can be detected. When the cleaning pump motor 13 is locked, the lower heater spherical heater unit 20 and the upper heater spherical heater unit 21 are automatically de-energized to prevent excessive temperature rise.

As described above, in the normal washing operation state,
It is possible to detect abnormal rotation of the cleaning pump motor 13 even under normally assumed adverse conditions (power supply voltage, ambient temperature change, etc.), and provide stable performance.

[0013]

According to the present invention, when the cleaning pump motor is locked under operating environment conditions (power supply voltage, ambient temperature change, etc.), the locked state can be detected by the circuit configuration of the present invention, and the cleaning pump motor and A dishwasher with excellent reliability and safety that can stop the machine before burning the heater unit can be provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the entire internal structure of a dishwasher.

FIG. 2 is a motor lock detection circuit diagram.

FIG. 3 is a diagram showing the relationship between the power supply voltage and the number of pulses due to changes in ambient temperature.

[Explanation of symbols]

13 ... Washing pump motor, 28 ... Thermistor, 29 ... Auxiliary coil, 30 ... Capacitor, 31 ... Rectifier circuit, 32 ...
Photo coupler, 33 ... Issuing diode, 34 ... Transistor, 35 ... Pulse generating circuit, 36 ... Microcomputer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Takeuchi 1-1-1, Higashitaga-cho, Hitachi-shi, Ibaraki Hirtata Engineering Co., Ltd. No. 1 In stock company Hitachi Co., Ltd. Taga factory (72) Inventor Kaoru Okano 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Prefecture Hitachi Co., Ltd. Taga factory

Claims (1)

[Claims] Claim: What is claimed is: 1. A washing pump motor condenser in a dishwasher, comprising a washing tank, a circulation pump, a blower fan, and a heater unit as main components, and controlling the heater unit to be continuously energized during a warm water heating process during washing. A dishwasher that detects changes in terminal voltage and automatically detects abnormalities when the circulation pump is locked.