JPS5938235Y2 - Washing machine water level detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water level detection device for a washing machine equipped with a washing/drying tub with non-porous side walls.

A conventional water level detection device for this type of washing machine consists of an electrode that receives overflowing water from a hole provided at a predetermined water level in the washing/spindle tank, and a rotating shaft of the washing/spindle tank. When the water supplied to the washing machine reaches a predetermined water level, the water overflows from the hole in the washing and dehydrating tank and wets the electrodes, so the electrode and the rotating shaft of the washing and dehydrating tank are electrically closed through the water. When this occurs, a water level detection circuit is operated, and the operation of the water level detection circuit mechanically closes the electromagnetic water supply valve to stop water supply.

However, in this configuration, when the washing and dehydration tank is rotated for dehydration in order to drain the soapy water during washing, the inside of the washing and dehydration tank installed in the washing and dehydration tank is filled with soapy water. Due to the soap's surfactant properties and the soap's ions, the electrode and the rotating shaft become electrically connected.
As a result, a problem occurred in that water was not supplied to the washing and dehydrating tank in the next step.

The present invention has been devised to solve the above-mentioned conventional problems, and the present invention will be explained below based on drawings showing embodiments thereof.

In Figure 1, 1 is the outer casing of the fully automatic washing machine, and 2 is the outer casing 1.
A dehydration receiving tank is disposed inside the dehydration receiving tank 2, and a metal support plate 3 is attached to the outer bottom of the dehydration receiving tank 2.

Reference numeral 4 denotes a rod whose lower part is inserted and supported by the support plate 3, and the upper end of this rod 4 is attached to the upper part of the outer casing 1 to suspend and support the dewatering tank 2.

'5 is a vibration-proof spring attached to the lower end of the rod 4, 6 is a drain port provided at the bottom of the dewatering tank 2, and a drain hose 7 is connected to the drain port 6.

Reference numeral 8 denotes a washing and dehydration tank rotatably installed in the dehydration receiving tank 2. This washing and dehydration tank 8 has a bottomed cylindrical shape with an open upper end, and the side wall has a tapered shape that increases in diameter as it goes upward. It has a non-porous structure and a non-porous wall.

Reference numeral 9 denotes a balance ring attached to the upper opening of the washing and dehydrating tank 8, and numeral 10 denotes a pulsator rotatably installed at the inner bottom of the washing and dehydrating tank 8.
The power of the motor 11 fixed to the support plate 3 is transmitted through the motor pulley 12, belt 13, pulley 14, rotating shaft 15, etc., and rotates.

Reference numeral 16 denotes a top plate installed at the top of the outer casing 1, which has a clothes slot 16.
A is provided.

17 is an operation panel, and this operation panel 17 has a built-in time switch (not shown), an electromagnetic water supply valve 18, etc., and the electromagnetic water supply valve 18 is a pressure hose connected to a water faucet (not shown). 19, and also communicates with a water supply port 20 that supplies water into the washing and dehydrating tank 8.

Reference numeral 21 denotes one electrode fixed to the inner wall of the dehydration receiving tank 2, and this one electrode 21 is configured to receive water overflowing from a hole 22 provided at a predetermined water level position of the washing and dehydration tank 8.

The support plate 3 supports a rotating shaft 15, and is electrically connected to the water in the washing/dehydration tank 8 via the rotating shaft 15. electrode 23
has been established.

The other electrode 23 and the one electrode 21 constitute a water level detection device.

Figure 2 shows a water level detection circuit, where 24 is an AC power supply, 25 is a transformer that steps down the voltage of the AC power supply 24, and 26 is a water level detection circuit.
27 is a rectifying diode, 27 is a smoothing capacitor, 28 is a current limiting resistor, and 29 is a Zener diode to obtain a constant voltage.

30 is a protective resistor on the other electrode 23 side, and 31 is a protective resistor on one electrode 21 side. This protective resistor 31 and the protective resistor 30 divide the voltage through the pair of electrodes 21 and 23, and the voltage is divided. A voltage applied to the base of transistor 32 is applied.

33 is a reverse voltage protection diode for the transistor 32;
4 is a capacitor for noise absorption, 35 is a transistor 3
2 collector resistance, 36 a base current limiting resistance of the transistor 37, 38 a human resistance of the transistor 37, 3
9 is a collector resistor of the transistor 37, and 40 is a transistor forming a delay circuit.The voltage applied to the base of this transistor 40 is divided by resistors 41, 42, and 43, and is divided by a capacitor 44 and a resistor 43 during charging. The delay time is controlled by setting a constant, and the transistor 40 is driven after the delay time has elapsed.

Reference numeral 45 denotes a gate human resistor of the thyristor 46, and 47 a relay that is turned on and off by the thyristor 46. The electromagnetic water supply valve 18 is controlled by the normally closed contact 47a of this relay 47.

48 is a diode for protecting the thyristor 46 due to the back electromotive force of the relay 47.

The operation in the above configuration will be explained.

When the electromagnetic water supply valve 18 is energized by a timer (not shown) or the like, the water supply passage is opened and water is supplied from the water supply port 20 into the washing and dewatering tank 8 .

In this water supply state, one electrode 21 provided on the dehydration receiver 2 has no water overflowing into the washing/dehydration tank 8, so its electric resistance is very high and the transistor 32 is in an off state.

As a result, the base of the transistor 37 is at a high potential.

Furthermore, the base potential of the transistor 40 constituting the delay circuit gradually decreases due to the capacitor 44 and the resistors 43 and 42.
0 does not turn on, so no potential is applied to the collector of the transistor 37 at this time.

When the transistor 40 is turned on after a predetermined period of time has elapsed, the transistor 37 is turned on for the first time because its base is at a high potential.

In this state, no potential acts on the gate of thyristor 46.

When the water supply progresses and the water level in the washing and dehydration tank 8 reaches a predetermined water level, as shown in FIG. Electrode 21
can be accepted.

As a result, one electrode 21 and the other electrode 23 are electrically connected to each other through the water overflowing from the hole 22 and the water in the washing and dehydrating tank 8, that is, they are electrically closed.
When a potential is applied to the base of the transistor 32, the transistor 32 is turned on.

At this time, the collector of the transistor 32 has a low potential, so the base of the transistor 37 has a low potential, so the transistor 37 is in an off state.

As a result, a potential is applied to the gate of the thyristor 46, the thyristor 46 is turned on, and the relay 47 is energized.
a is opened to stop energizing the electromagnetic water supply valve 18.

This will stop the water supply.

The fully automatic washing machine shown in the embodiment of the present invention automatically performs a cycle of washing, draining, dewatering, rinsing, draining, and dewatering, and when draining after the first washing, the washing and dehydrating tank 8 In order to drain the soapy water inside, the inside of the dehydration receiving tank 2 becomes wet with soapy water, and one electrode 21 gets wet, and the rotating shaft 15 of the washing and dehydration tank 8 also gets wet.

And since soapy water is a surfactant for soap ions,
The resistance is so small that it cannot be distinguished from the resistance of water described above, and one electrode 21 and the other electrode 23 are in a conductive state.

However, in the embodiment of the present invention, for a predetermined period of time after drainage, the transistor 40 constituting the delay circuit
Capacitor 37 that controls the gate power of thyristor 46
Since no potential is applied to the collector of
The thyristor 46 can be kept off for a predetermined period of time after draining.

In other words, since time is allowed for the soapy water to run off from one electrode 21, after this predetermined time has passed, one electrode 21 becomes dry, and as a result, the insulation resistance between both electrodes 21 and 23 after the soapy water is drained is reduced. Since the value is high, water is supplied in a stable state during the next rinsing process.

As described above, according to the present invention, the water level detection circuit is provided with a delay circuit that delays the operation of the drive unit that controls the energization of the electromagnetic water supply valve for a predetermined period of time. Even if the soapy water in the washing and dehydration tank is drained and the soapy water wets the dehydration tank and the pair of electrodes, the delay circuit prevents the soapy water from draining from one electrode in the dehydration tank. Since the time for the water to turn off can be secured, this has the practical effect of being able to supply water in a stable state during the next process.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a fully automatic washing machine equipped with the water level detection device of the present invention, Fig. 2 is a water level detection circuit diagram of the washing machine, and Fig. 3 is a main part showing the water level detection operation of the washing machine. FIG. 2...Dehydration receiving tank, 8...Washing/dehydration tank, 18...Electromagnetic water supply valve, 20...Water inlet, 21... One electrode, 22...hole, 23...other electrode, 37.40...
・Transistor, 43... Resistor, 44...
...Capacitor, 46...Thyristor.

Claims (1)

[Scope of utility model registration request] A washing and dehydration tank with a non-porous side wall, a light leakage and dehydration tank (a rigidly arranged dehydration receiving tank, a water supply port for supplying water into the washing and dehydration tank, and this water supply port) An electromagnetic water supply valve that controls the water supply from the washing and dehydrating tank, one electrode that receives water overflow from a hole provided at a predetermined water level position of the washing and dehydration tank, and this one electrode constitute a water level detection device, and the electromagnetic water supply valve and the other electrode that operates the water level detection circuit for valve control.
A water level detection device for a washing machine, characterized in that the water level detection circuit is provided with a delay circuit that extends the operation of a drive unit that controls energization of an electromagnetic water supply valve for a predetermined period of time.