JPS5924839B2 - Washing machine water level control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides water level control for a fully automatic washing machine that detects changes in the electrical resistance of water, operates a water supply valve, and controls the amount of water in the washing tub. This relates to improvements in equipment.

Conventionally, this type of water level control device, as shown in Fig. 1, has a gap between the mechanical part of the washing machine and a water level detection plate installed on the inner side wall of the laundry room, where the water flowing out from the water spout at the top of the washing/spin-drying tub is connected. When connected, the electrical resistance between them changes, the water level detection device operates, and the water supply valve closes.

In addition, washing machines that use this type-standard (incorporated) device are:
The laundry room (outermost case) is made of electrically insulating material such as synthetic resin, and there is no connection between the mechanical part and the water level detection plate except for water flowing out from the water spout at the top of the washing and dehydrating tank. The mechanical part of the washing machine and the water level detection plate are electrically insulated through the air insulating layer between them and the wall of the laundry room.

However, with this method, the electrical resistance of the detection plate on the wall of the laundry room and the mechanical part is the electrical resistance of the water flowing out from the water spout (
It needs to be sufficiently higher than part B), but especially if a washing machine is used for many years with powdered soap and highly hard water, the soap content of the powdered soap will increase the amount of calcium in the hardness water. , combines with magnesium to become a metal soap containing water, which adheres to the walls of the laundry room and gradually grows, and as mentioned above, the laundry room (outermost case) is made of electrically insulating material such as synthetic resin. Although the mechanical part of the washing machine and the water level detection plate are normally electrically insulated through the wall of the laundry room, the mechanical part and the water level detection plate are The electrical insulation state is lowered due to the relationship R, L/S due to the metal soap adhering to the wall of the laundry room, and eventually the space becomes completely conductive.

Here, R is the electrical resistance on the wall side of the laundry room between the mechanism part and the water level detection plate, L is the distance (constant) on the wall side of the laundry room between the mechanism part and the water level detection plate, and S is the resistance between the mechanism part and the water level. This is the amount of soap adhesion (total soap adhesion area or total laminated cross-sectional area) on the inner wall side of the laundry room between the sensor plate and the detection plate.

Therefore, the water level detection device operates even though there is no water in the washing tub.
There are cases where water cannot be supplied, and there is a drawback that it is often necessary to readjust the operating resistance value of the water level detection device to a resistance value smaller than the value in part (5) each time.

However, the main control M1 device of the present invention is provided with another detection plate on the exterior side wall in order to automatically adjust the sensitivity, and this detection plate detects changes in electrical resistance due to side υ■ dirt (metallic soap). However, this feature is characterized in that the operating point of the water level detection circuit is automatically set to prevent malfunction.

The following description will be given based on the drawings showing an embodiment of the present invention. In FIG. 2, reference numeral 1 denotes a resin-molded laundry room with a watertight structure, and on the inside wall of the room there is a strip-shaped electrode 2 for detecting the water level. Also, an electrode 3 for detecting dirt (metal soap) on the side wall is fixedly attached.

Reference numeral 4 denotes a washing and dewatering tank, which is provided with a dewatering port 5 at the top and a water spout 6 for detecting the water level in the tank at the bottom.

The relationship between the dewatering port 5 and the water spout 6 is such that the water flowing out from the water spout 6 sufficiently reaches the water level detection electrode 2 provided on the side wall of the laundry room.

Reference numeral 7 is a machine room, and inside this machine room there is a mechanical part 9 that operates the well-known washing machine, especially a pulsator 8, and a dewatering/washing tank.
and the electric motors that drive them.

Reference numeral 10 denotes a dewatering shaft, and 11 a sealing portion made of an electrically insulating material such as synthetic rubber, which is designed to prevent water from leaking from the laundry room 1.

12 is a water supply valve that supplies water to the washing and dehydrating tank.

Next, to explain the control circuit part, 13 is a power transformer, 14 is a rectifier that converts secondary side AC into DC, 15 is a smoothing capacitor, 16 is an output transistor, and the collector of this transistor 16 has a relay 17. It is connected.

18 is a diode that absorbs the back electromotive force generated when the relay is turned off.

19 and 20 are resistors for driving the transistor 16.

The transistor 21 operates due to a change in electrical resistance (between the electrode 3 and ground) due to dirt (metal soap) on the inner wall of the laundry room 1.

For example, if the resistance between the electrode 3 and ground 0 is Rxl, a divided voltage will be generated in the resistor 23, and this voltage will be applied to the penis of the transistor 21, so the resistor 24 connected to its emitter will be applied to the penis of the transistor 21. A voltage approximately equal to the voltage is generated at , and the operating point of the transistor 25 for water level detection is determined.

Furthermore, a water level detection electrode 2 is connected to the base of this transistor.

Note that 28 represents a power switch, and 29 represents an AC power source.

Next, to explain the operation, first, when the power switch 28 is closed, the resistance 2
3 is generated, and a voltage approximately equal to the current amplified by the transistor 21 is applied to the emitter of the water level detection transistor.

(This voltage will increase if there is a lot of dirt on the side wall because its electrical resistance will decrease, and conversely, if there is little dirt, it will decrease.

) At this time, between the water level detection electrode 2 and the mechanical part (ground)
Since there is no water, the electrical resistance between them is high, with a resistance of 27
Since the voltage generated at is on the a side, the electric circuit of the electromagnetic water supply valve 12 is closed, the electromagnetic water supply valve operates, and water supply to the washing tub/dehydration tub 4 is started.

In this way, water accumulates in the washing and spin-drying tank 4, reaches the water level detection water spout 6, and starts flowing out. However, this outflow amount is a small value compared to the inflow amount of the electromagnetic water supply valve 12, so the water level does not change. further rises, the water pressure at the water spout is increased, and laundry room 1
When reaching the band-shaped water level detection electrode 2 provided on the side wall of the transistor 25, the electrode and the mechanical part (ground) are connected by water, so the electrical resistance between them decreases, and the transistor 25
The base voltage is higher than that of the emitter, so it is turned on.

Since the transistor 16 driven by this transistor is also turned on at the same time, the relay 17 also operates,
Since the electrical contact a is opened, the electric circuit of the electromagnetic water supply valve 12 is cut off, and the electromagnetic water supply valve is closed to complete water supply.

Also, since transistor 16 is turned on, transistor 2 is turned on by resistor 27 connected to this collector.
5 continues the ON state and maintains this state as long as the power supply 28 is not set to 0FFL.

Note that the voltage used for this water level control is kept below IOV by the transformer 13, so there is no effect on the human body.

In addition, in the above embodiment, in order to maintain electrical insulation between the mechanism part and the water level detection plate, the laundry room and the seal part were molded from electrically insulating materials such as synthetic resin and synthetic rubber, but the laundry room was made of metal. It goes without saying that the present invention is also applicable to a washing machine in which only the seal portion 11 is made of an electrically insulating material.

Therefore, according to the present invention described above, even if the resistance decreases due to dirt on the exterior side wall caused by long-term use of the washing machine or due to overfilling of detergent, etc., the exterior side wall will not be affected.
Since it is equipped with a detection plate that automatically adjusts, this detection plate detects changes in electrical resistance due to dirt on the side wall, etc., and can automatically set the operating point of the water level detection circuit, preventing malfunctions like in the past. This allows for smooth operation without causing any problems.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional washing machine, FIG. 2 is a sectional view of a washing machine showing an example of the present invention, and FIG. FIG. 4 shows an electric circuit diagram according to the present invention. In the figure, 1 is a laundry room, 2 is a water level detection electrode, 3 is a dirt detection electrode, 4 is a washing/dehydration tank, and 6 is a water spout.

Claims (1)

[Claims] 1 Water flowing out from the upper water spout of the laundry tub that also serves as a spin dryer,
In a fully automatic washing machine that detects the water level using the water level detection electrode on the inner wall of the laundry room and controls the electromagnetic water supply valve, the dirt on the inner wall of the laundry room is detected by the dirt detection electrode fixed to the side wall of the laundry room, and the level of dirt is detected. 1. A water level control device for a washing machine, comprising a control circuit that automatically changes the operating point of a water level detection circuit according to the conditions.