KR19980031796U - Washing machine water level detection device - Google Patents

Abstract

The present invention induces a change in pressure caused by a change in the water level in the washing tank to a change in the capacity of a capacitor using a fixed electrode plate and a variable electrode plate at the bottom of the circuit board, and outputs a change in the oscillation frequency accordingly, thereby reducing the installation volume and providing a stable output. In order to provide a water level detection device of the washing machine to secure the accurate water level to ensure that, in the water level detection device formed on the pressure hose of the washing machine to detect the amount of water in the tank, the cross section is formed in a square and the bottom surface A pressure sensor body having a pressure hose, a circuit board formed at an upper end of the pressure sensor body and having a fixed electrode plate at a bottom thereof, a variable electrode plate formed at a bottom of the fixed electrode plate and having an insulating member at a bottom thereof, and the pressure sensor A die formed transversely on the bottom surface of the insulating member so as to divide the body into a circuit portion and an air inlet portion; It is characterized in that it is provided with an aphram.

Description

Water level sensor of washing machine

The present invention relates to a water level sensing device of a washing machine. More specifically, the pressure change according to the water level change in the washing tank is induced to the capacity change of the condenser using the fixed electrode plate and the variable electrode plate on the bottom of the circuit board, and thus the change of the oscillation frequency accordingly. By detecting the output to reduce the installation volume, and also to ensure a stable output to the water level detection device of the washing machine that can detect the correct water level.

1 is a schematic cross-sectional view of a conventional washing machine, which has a rectangular main body 1 and a water tank 2 in which a predetermined amount of washing water is freshly formed, and a vertical lower portion from an upper end of a buffer member 7 and a main body 1 formed at one side thereof. It is installed hanging inside the main body 1 by a hook rod 7a formed as a.

In addition, the cylindrical washing tank 3 is installed inside the water tank 2 in a rotatable state, and the washing tank 3 is provided with a myriad of holes 3a penetrating the side wall, and is supplied to the washing tank 3. The water flows toward the water tank 2 so as to match the water level of the washing tank 3 and the water tank 2, and these holes 3a discharge the washing water generated from the wet feeling in the dehydration process toward the water tank 2.

On the other hand, the stirring blade 4 is rotatably installed on the inner bottom of the washing tank (3). Stirring blade (4) is to be rotated forward and reverse in the washing process, to stir the wash water supplied into the washing tank (3) to generate a rotary water flow.

And, the power switching means 6 which is rotated by the motor 5 is installed in the center of the bottom surface of the water tank (2). The power switching means 6 has a washing shaft (6a) and a dehydration shaft (6b) is formed on the upper side, the washing shaft (6a) is combined with the stirring blade (4) and the dehydration shaft (6b) is the bottom of the washing tank (3) Is coupled to.

A filter 9a is installed at one lower side of the main body 1, and a sprinkling pipe 8 is formed at the top of the water tank 2 to sprinkle the wash water passing through the filter into the washing tank 3. Further, the bottom of the water tank 2 and the filter 9a are connected by a hose 9b, and a pump 9 is installed between the filter 9a and the sprinkling pipe 8, and a drain valve behind the pump 9 is provided. 9c) is installed to drain the wash water during dehydration.

On the other hand, the pressure hose (10a) is formed on one side of the water tank (1) and the water level sensing device (10) is formed on the top of the main body 1 is configured to be connected to the pressure hose (10a).

In the conventional washing machine configured as described above, the laundry feeling is contained in the washing tank 3 and the air pressure is delivered to the water level sensing device 10 through the pressure hose 10a in the state where the washing water is supplied. At this time, when the water level detecting device 10 detects a predetermined pressure, washing is stopped after the water supply is stopped.

In the washing process, when the motor 5 rotates forward and backward, its rotational force is transmitted to the power switching means 6 and decelerated by the power switching means 6, and then the rotational force is transmitted to the stirring blade 4 through the washing shaft 6a. do.

At this time, when the stirring blade 4 is rotated forward and reverse, the washing water causes a rotational water flow, and the washing progresses while the laundry is rubbed against each other by the rotational water flow.

In addition, during the washing process, a part of the washing water is pumped toward the sprinkling pipe 8 above the washing tank 3, and the pumped washing water is sprayed into the washing tank 3. That is, when the pump 9 is operated, the wash water is filtered through the filter 9a through the hose 9b connected to the bottom of the water tank 2, and then the pumped wash water is pumped toward the water spray pipe 8, and the pumped wash water 3 It can be sprayed inside to improve washability.

After the washing is completed, when the drain valve 9c is opened, the washing water is completely drained and then dehydration proceeds.

When the motor 5 rotates at a high speed in the dehydration process, the washing shaft 6a and the dehydration shaft 6b are rotated together by the power switching means 6 at a high speed, and the washing tank 3 is rotated at a high speed. Therefore, all the laundry water is removed, the process associated with all the laundry is terminated.

In the conventional washing machine as described above, the water level detecting device 10 is to be able to automatically adjust the water supply amount according to the amount of laundry to be put into the washing tank 3 to open the water supply valve (not shown) to perform the water supply In order to control the water level of the washing tank 3 by stopping the water supply by blocking the water supply valve (not shown) by the increase in the air pressure according to the water supply.

2 and 3, FIG. 2 is a cross-sectional view of a conventional water level sensor, which has a rectangular cross section and has a pressure sensor body 11 having a pressure hose 10a formed on the bottom thereof, and A coil 14 formed to be fixed to the upper end of the pressure sensor body 11 to generate an electromagnetic field, a core 15a formed in the coil 14 to move up and down, and having a spring 15 formed at an upper end thereof, and in a plate shape. It is formed of a pusher 12 formed in contact with the lower end of the core (15a), and a diaphragm 13 formed of a soft rubber and formed in the horizontal direction on the pressure sensor body (11).

3 is an LC oscillator circuit diagram applied to a conventional water level sensing device, and includes an inductance L which is changed into the coil 5, a separate capacitor C1, C2, an inverter IV1, IV2, and a resistor. (R1) and (R2) are connected, and the control part 16 is formed in the output terminal, and is comprised.

The water level detection device of the conventional washing machine configured as described above is filled with water in a washing tank (not shown) to the diaphragm 13 of the bottom surface of the pressure sensor body 11 through the pressure hose 10a, thereby inductance of the coil 15a. Change (L) Therefore, the LC oscillation circuit composed of condensers C1 (C2) and inverters IV1 (IV2), etc., oscillates, and at the output stage, it is measured to open and shut off the water supply valve (not shown) to adjust the water level. Given.

That is, as the pressure change is applied to the diaphragm 13, the pusher 12 moves to the upper end, so that the core 15a contacted on the pusher 12 is formed by the surrounding coil 15a. It moves upward while pushing the spring 15 within.

By the operation of the core 15a, the inductance L is changed in the coil 15a, and as shown in FIG. 3, a capacitor C1 separate from the inductance L of the coil 15a ( The oscillation frequency is changed in the LC oscillation circuit connecting C2) and inverters IV1 (IV2) and resistors R1 (R2), and according to the oscillation frequency change in the controller 16 connected to the oscillation circuit. It is possible to detect the change in pressure caused by the change in the water level in the washing tank (not shown).

Accordingly, in the conventional water level sensing device, a coil and a core for forming a change of an electromagnetic field are essentially installed by applying the principle of the LC oscillation circuit shown in FIG. 3, thereby increasing the volume of the coil and the core. But the structure was also complicated.

The present invention was created in view of the above problems. The pressure change caused by the change of the water level in the washing tank is induced to the capacity change of the capacitor using the fixed electrode plate and the variable electrode plate on the bottom of the circuit board, and the oscillation frequency is outputted accordingly. By detecting, reducing the installation volume and at the same time to ensure a stable output to provide a water level detection device of the washing machine that can detect the correct water level.

1 is a cross-sectional view of a conventional washing machine.

2 is a cross-sectional view of a conventional level sensor.

3 is a circuit diagram of an L-C oscillator applied to a conventional water level sensor.

Figure 4 is a cross-sectional view of the water level detecting device showing an embodiment of the present invention.

5 is an R-C oscillator circuit diagram applied to the present invention.

* Description of the symbols for the main parts of the drawings *

20-pressure sensor body, 21-circuit section,

22-air inlet, 23-pressure hose,

24-diaphragm, 25-circuit board,

26-fixed plate, 27-variable plate,

28-insulating member, 29-spring.

In order to achieve the above object, the present invention is formed in the pressure hose of the washing machine in the water level sensing device for detecting the amount of water in the tank, the cross section is formed in a square and the pressure sensor body provided with the pressure hose on the bottom surface; A circuit board formed at an upper end of the pressure sensor body and having a fixed electrode plate at a bottom thereof, a variable electrode plate formed at a bottom of the fixed electrode plate and provided with an insulating member at a bottom thereof, and partitioning the pressure sensor body into a circuit part and an air inlet part. A diaphragm formed in the transverse direction is provided on the bottom surface of the insulating member.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a cross-sectional view of the water level detecting device showing an embodiment of the present invention, the pressure sensor body 20 and the pressure sensor body 20 is provided with the pressure hose 23 on the bottom surface is formed in a square cross-section A circuit board 25 is formed on the top and has a fixed electrode plate 26 on the bottom.

The bottom of the fixed electrode plate 26 is formed with a variable electrode plate 27 having an insulating member 28 on the bottom surface, a predetermined distance between the insulating member 28 formed on the bottom and the pressure sensor body 20 of the upper end. The spring 29 is formed and is configured to flow up and down according to the air pressure flowing from the pressure hose 23.

On the other hand, the diaphragm 24 formed in the transverse direction on the bottom surface of the insulating member 28 is formed to partition the pressure sensor body 20 into the circuit portion 21 and the air inlet portion (22).

5 is a circuit diagram of an RC oscillator applied to the present invention, in which a series-connected NAND gate (NAND1) (NAND2), a resistor (R1) (R2) and a capacitance (C) connected in parallel thereto, and an output terminal of the circuit ( The control unit 30 receives Vo). The capacitance C is composed of a variable electrode plate 27 and a fixed electrode plate 26, the capacitance of which is variable, and the resonance angle frequency fo is output to the output terminal Vo when the R-C circuit resonates.

S represents the area of the variable electrode plate and the fixed electrode plate, and d represents the distance between both ends.

Referring to the operation of the subject innovation configured as described above in detail.

The water level sensing device formed at the top of the main body to detect the state of the water level and the amount of the laundry in the washing tank (not shown) according to the pressure of the air applied through the pressure hose 23 formed at the bottom of the pressure sensor body 20 The diaphragm 24 is moved to the top.

At this time, as the air is introduced into the air inlet 22 at the bottom of the diaphragm 24, the diaphragm 24 made of soft rubber is pushed upward.

Therefore, when the variable electrode plate 28 formed on the upper portion of the diaphragm 24 is moved to the upper end and the gap between the fixed electrode plate 26 and the variable electrode plate 27 is narrowed, the capacitance C is changed as a result.

At this time, the spring 29 is to maintain a predetermined interval to prevent the short circuit of the positive electrode plate (26, 27) and to be quickly restored to the original position when the air pressure of the bottom surface is removed.

The change principle of the capacitance C according to the gap between the fixed electrode plate 26 and the variable electrode plate 27 due to the water level will be described in more detail with reference to FIG. 5.

First, if the output of the NAND gate (NAND1) is high, and the output of the other NAND gate (NAND2) is low, the voltage at point A is rising with the RC time constant. Therefore, when the voltage at the point A exceeds the threshold voltage Vr of the NAND gate NAND1, the NAND gate NAND1 is inverted output low and the other NAND gate NAND2 becomes high.

Therefore, when the voltage at point A becomes Vcc + Vr, and the voltage starts to drop due to the RC time constant and becomes lower than the voltage of Vr of the NAND gate NAND1, the NAND gate NAND1 and the other NAND gate NAND2 become different. By inverting output, Vo goes low and the voltage at point A becomes -Vr and then oscillation continues as before.

At this time, the resonance angular frequency fo appearing at the output terminal Vo at the time of resonance of the R-C circuit can be obtained as follows.

On the other hand, since the fixed electrode plate 26 and the variable electrode plate 27 are not in a vacuum state, when the dielectric constant epsilon of air is applied, Equation 2 is obtained.

Here, d is the distance between the fixed plate 26 and the variable plate 27, S is the cross-sectional area of the positive plate (26, 27), ε represents the dielectric constant of the air.

Therefore, the area S of the fixed electrode plate 26 and the variable electrode plate 27 is the same, and there is a constant capacitance C between both ends, whereby the width d between both ends is narrowed according to the air pressure applied from the bottom of the variable electrode plate 27. C becomes large.

In addition, when Equation 2 is substituted into Equation 1 according to the change of the C value, the resonance angle frequency fo becomes as shown in Equation 3 below.

Therefore, the resonant angular frequency fo and the distance d between both ends have a proportional relationship such as fo ∝ d.

Therefore, since the area S, the resistances R1, R2 and the air dielectric constant ε are fixed in the circuit, the change of the frequency value after the initial state and the air pressure is applied by the distance d is sensed. The water level is measured.

The above description is only one embodiment of the present invention and can be changed as many as possible within the scope of the present invention.

The present invention induces a change in pressure caused by a change in the water level in the washing tank to a change in the capacity of a capacitor using a fixed electrode plate and a variable electrode plate at the bottom of the circuit board, and outputs a change in the oscillation frequency accordingly, thereby reducing the installation volume and providing a stable output. It is effective to detect the correct water level by ensuring.

Claims (2)

In the water level sensing device is formed on the pressure hose 23 of the washing machine to detect the amount of water in the water tank (2), A pressure sensor body 20 having a cross section formed in a quadrangle and provided with the pressure hose 23 at a bottom thereof; A circuit board 25 formed at an upper end of the pressure sensor body 20 and provided with a fixed electrode plate 26 at a bottom thereof; A variable electrode plate 27 formed at a lower end of the fixed electrode plate 26 and having an insulating member 28 at a bottom thereof; Water level sensing device of the washing machine, characterized in that the diaphragm 24 formed in the transverse direction on the bottom surface of the insulating member 28 to partition the pressure sensor body 20 into the circuit portion 21 and the air inlet portion 22 . The method of claim 1, wherein the variable electrode plate 27 is a spring 29 is formed between the insulating member 28 formed at the lower end and the pressure sensor body 20 of the upper end to the air pressure flowing from the pressure hose 23 The water level detection device of the washing machine characterized in that it flows up and down.