JPH01320098A - Water level detecting device for washing machine - Google Patents

Abstract

PURPOSE:To simplify the fitting and reduce the cost by integrating a coil and capacitors, separating an inverter of an oscillating circuit, and fitting the inverter to the control circuit of a washing machine. CONSTITUTION:A diaphragm 1 moved by the pressure due to the water level change in a washing machine, a magnetic material 2 fitted on the diaphragm 1, a coil 3 with variable inductance by the movement of the magnetic material 2, and a water level detecting circuit 11 inputted with the oscillation signal of an oscillating circuit 12 constituted of the coil 3 as the resonance coil, capacitors 6 and 7 and an inverter 9 to detect the water level are provided, the coil 3 and the capacitors 6 and 7 are integrated, thereby their alignment and services are simplified even if the value of the coil 3 and the capacitors 6 and 7 are dispersed because the coil 3 and the capacitors are integrated, the printed circuit board required for the oscillating circuit 10, moisture-proof materials, and components for noise countermeasures can be jointly used with the water level detecting circuit, thus an inexpensive water level detecting device can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a water level detection device for detecting the water level in a tub of a washing machine.

2. Prior Art Conventionally, water level detection devices for this type of washing machine are as shown in Figs. 3 and 4.
The configuration was as shown in FIG.

, Figure 3 shows a cross-sectional view of the water level detection device, where 1 is a diaphragm that moves up and down due to the pressure associated with changes in the water level in the washing tub, 2 is a magnetic body attached to this diaphragm, As this magnetic body 2 moves up and down together with the diaphragm 1, the inductance of the coil 3 placed around the magnetic body 2 changes, and this inductance change is converted into an electrical signal to detect changes in the water level in the washing tub. This is what I am trying to do. 4 is a spring that makes the change in inductance linear with respect to pressure, and 6 is a case.

FIG. 4 is an electric circuit diagram for converting the inductance change with respect to pressure explained in FIG. 3 into an electric signal (frequency). In the figure, numerals 2 and 3 are the magnetic body and coil described in FIG. 3, respectively. 6 and 7 are capacitors, 8 is a resistor, and 9 is an inverter. 12 is a capacitor for noise countermeasures in the power supply circuit. With this circuit, the coil 3 and capacitors e and 7 form a resonant circuit, and constitute a rooting circuit 10. The output of this oscillation circuit 1Q is detected by the water level detection circuit 11 as the water level. The relationship between the frequency and pressure of the oscillation circuit shown in FIG. 4 is shown in FIG. If the horizontal axis is pressure and the vertical axis is frequency, as shown in the straight line & shown in the figure, the higher the pressure, that is, the more the magnetic body 2 shown in Figure 3 moves upward due to pressure, the more the inductance increases, and the frequency increases. This shows that the value is decreasing.

Problems to be Solved by the Invention In such a conventional configuration, the frequency corresponding to each pressure is determined by the variation in the inductance of the coil 3 and the variation in the capacitor 6.7. , a coil 1130 having a built-in coil 3;
Since the capacitor 6.7 and the oscillation circuit section 10 including the inverter 9 are integrated to suppress variations in the inductance of the coil 3 and variations in the capacitor 6.7, the printed circuit board 101 on which the oscillation circuit is mounted is used.
Moisture-proof material 102 and case 1 for moisture-proofing the oscillation circuit
03 is required, and a noise countermeasure capacitor 12 for the power supply circuit necessary for the oscillation circuit must be mounted, which poses a problem of increased cost.

The present invention solves these problems, and aims to suppress variations in coils and capacitors and reduce the number of parts.

Means for Solving All Problems In order to achieve the above objects, the present invention comprises: a diaphragm that moves due to pressure associated with changes in water level in a washing tub; a magnetic body mounted on the diaphragm; The coil has a coil whose inductance changes as it moves, an oscillation circuit section that uses the coil as a resonant coil, and includes a capacitor and an inverter, and a water level detection circuit that receives an oscillation signal from the oscillation circuit section and detects the water level, and the coil and a capacitor are integrated, and an oscillation circuit section consisting of the inverter is mounted within the water level detection circuit.

With this configuration, even if the values of the coil and capacitor vary, since the coil and capacitor are integrated, adjustment and servicing are easy.In addition, the printed circuit board and case necessary for the oscillation circuit, moisture-proof materials, and noise countermeasures can be easily adjusted and serviced. Since parts and the like can be shared with the water level detection circuit, an inexpensive water level detection device can be realized.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the water level detection device for a washing machine according to the present invention, in which 2 is a magnetic body attached to a diaphragm that moves up and down due to the pressure associated with changes in water level;
is a coil that is attached around the outside of the magnetic body 2 and whose inductance changes as the magnetic body 2 moves up and down;
Reference numerals 6 and 7 designate capacitors using the coils as resonant coils, the leads on one side of each are connected to lead terminals 31 and 32 of the coil 3, and the leads on the other side are common. Lead terminals 31 and 32 of coil 3 and common lead terminal 61 of capacitors 6 and 7 are connected to lead wires 311 .
322, 611, inverter 9 and water level detection circuit 1
1 is connected to a control circuit 12 mounted on the same printed circuit board.

FIG. 2 is an electrical circuit diagram of FIG. 1, in which the same components as in FIG. 1 are given the same reference numerals. Reference numeral 13 denotes a coil unit consisting of the coil section and capacitor shown in FIG.

In the above configuration, the only circuit section that requires a printed circuit board, moisture-proof material, and noise countermeasures is the control circuit 12 shown in FIG. The printed circuit board and its moisture barrier material are no longer necessary. Furthermore, since the coil 3 and capacitors 6 and 7 are integrated, variations in these three parts can be adjusted, making replacement easy even in the event of a failure such as a diaphragm failure or a disconnection of the coil. be.

Effects of the Invention As described above, according to the present invention, the coil and the capacitor are integrated, the inverter of the oscillation circuit section is separated, and the inverter is mounted in the control circuit of the washing machine, so that a separate printed circuit board is required. This makes it possible to omit moisture-proof materials, electronic components for noise prevention, etc., making it possible to simplify mounting and reduce costs.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a water level detection device for a washing machine according to an embodiment of the present invention, Fig. 2 is an electric circuit diagram of the same device, Fig. 3 is a sectional view of a coil portion of a conventional water level detection device, and Fig. 4 5 is an electric circuit diagram of a conventional water level detection device, FIG. 5 is a graph showing pressure and frequency characteristics of the water level detection device, and FIG. 6 is an external perspective view of a conventional water level detection device for a washing machine. 1...Diaphragm, 2...Maternal body,
3...Coil, 4...Spring, 6
・・・・・・Case, 6.7・・・Capacitor,
8... Resistor, 9... Inverter, 10
...Oscillation circuit section, 11 ...Water level detection circuit, 3o ... Coil section, 101 ... Printed circuit board, 102 ... Moisture-proof material , 103...
...Case, 12...Control circuit section. Name of agent: Patent attorney Toshio Nakao and 1 other person2-
Gosazaki Body Figure 1
Togoil G, 1--Condinobu Fig. 2 1-m-gui

Claims (1)

[Claims] a diaphragm that moves due to pressure associated with changes in water level in the washing tub; a magnetic body attached to the diaphragm; a coil whose inductance changes due to the movement of the magnetic body; a resonant circuit comprising the coil and a capacitor; It has an oscillation circuit section consisting of an inverter, etc., and a water level detection circuit that receives an oscillation signal from the oscillation circuit section and detects the water level, and the coil and the capacitor are integrated, and the oscillation circuit section consisting of the inverter is connected to the oscillation circuit section. A washing machine water level detection device implemented within the water level detection circuit.