JPS6311038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a washing machine widely used in homes that automatically performs washing and rinsing by supplying water to a washing tub up to a specified water level.

(b) Prior art In conventional systems that automatically wash and rinse water by supplying water to a specified water level to a washing tub, the water level in the washing tub is detected by using air in an air trap that is compressed according to the water level in the washing tub. This was done by controlling a diaphragm pressure switch.
In such a device, once the water level in the washing tub reaches the specified water level and the pressure switch is set, the pressure switch does not return to its original state (does not reset) even if the water level drops a little. Therefore, when washing or rinsing, if a foreign object gets into the drain valve and it does not close completely, or if water leaks due to deterioration of the gasket, the water level will drop, but the pressure switch will not reset, so washing or rinsing will continue. . As a result, a small amount of water is needed to rotate the rotor to perform washing and rinsing, which not only deteriorates washing and rinsing performance, but also
The fabric would be severely damaged, and the load on the drive motor that rotates the rotor blades would increase, resulting in increased heat generation, which could lead to product failure.

(C) Purpose of the Invention The present invention is designed to prevent fabric damage by stopping the rotor and automatically supplying water to the specified water level when the water level in the washing tub drops below the specified water level during washing or rinsing. An object of the present invention is to provide a washing machine that can suppress the load on the drive motor and reduce the load on the drive motor.

(D) Structure of the Invention The present invention uses a semiconductor pressure sensor that detects the air pressure in an air trap that is compressed according to the water level of the washing tub and generates a signal according to the water level as a means for detecting the water level of the washing tub. When the water level in the washing tub drops below the specified water level during washing or rinsing, it receives a signal from this pressure sensor.
A control means is provided for stopping the rotor and opening the water supply valve to supply water to the washing tub up to the specified water level.

(E) Embodiment Figure 1 shows the overall structure of a washing machine, where 1 is an outer box;
2 is an outer tank that is elastically suspended within the outer box 1 by a hanging rod (not shown). Inside the outer tub 2, a dehydrating/washing tub 5 having a large number of dehydrating holes 4 in its peripheral wall is installed. A balance ring 6 is attached to the edge of the washing tub 5, and a rotary blade 7 is provided at the center of the bottom. 8 is a drive motor, small pulley 9, belt 1
0. The dewatering shaft 12 to which the washing tub 5 is fixed and the blade shaft 13 to which the rotary blade 7 is fixed are rotated via the large pulley 11. Reference numeral 14 denotes a bearing case incorporating a brake device that applies a brake to the dehydration shaft 12 and a clutch device that controls the transmission of rotational force to the dehydration shaft 12.
A drain port 15 is provided at the bottom of the outer tank 2, and a drain hose 17 having a drain electromagnetic valve 16 is connected to the drain port 15.

An air trap 18 is provided at the lower part of the side wall of the outer tub 2, and the air inside is compressed according to the water level in the washing tub 5. is communicated with. FIG. 2 shows the structure of the pressure sensor 20. A silicon pellet 23 serving as a diaphragm portion is adhered to the header 22, and a cap 24 having a pressure introduction pipe 21 is welded to the outside. Four piezo diffused resistors 25 to 28 are installed in the diaphragm portion of the silicon pellet 23. Air trap 1 from pressure introduction pipe 21
When the pressure inside 8 is introduced, the diaphragm portion is deformed, and the resistance values of the piezo diffusion resistors 25 to 28 change. By bridge-coupling the piezo diffused resistors 25 to 28 as shown in FIG.
Take it out from 9'. In Figure 3, 30 is a constant current circuit that supplies a constant current of 1.5 [mA] to the bridge. External resistors 31, 32, and 33 are used for temperature compensation, sensitivity, and zero point adjustment of the pressure sensor. The output voltage of the pressure sensor is proportional to the water level in the washing tub 5, as shown in FIG. In Figure 2, 34 is an adhesive, 35 is an insulating material, and 3
6 is a conductor, and 37 is six lead terminals, which correspond to point P in FIG. 3.

FIG. 5 shows a block circuit diagram of the control device, and the washing machine of this embodiment is controlled by the microcomputer 3.
This is done by 8. Microcomputer 3
Information from the start button and washing course setting button shown at 39 and information from the pressure sensor 20 are inputted to 8, and this information is judged to control the drive motor 8, drain solenoid valve 16, water supply solenoid valve 40, etc. Control. In the figure, 41 to 45 are interfaces, and 46 is a drain valve 16 other than the drive motor 8 and water supply solenoid valve 40.
represents a load section such as

Next, the operation will be explained based on the flowchart of FIG. Operation is started by operating the start button. First, the water supply electromagnetic valve 40 is opened to supply water to the washing tub 5 until the output voltage of the pressure sensor 20 reaches a value a in FIG. When water is supplied to the washing tub 5 up to the specified water level H, the output of the pressure sensor 20 becomes a,
Close the water supply solenoid valve 40. Next, the washing process time T
is set, the drive motor 8 is energized, and the rotor blade 7
Rotate and start washing. When the water level in the washing tub 5 drops to h during washing and the output of the pressure sensor 20 drops to c, the microcomputer 38
The power supply to the drive motor 8 is cut off and the timing operation of the time T is stopped. At the same time, water supply solenoid valve 40
is energized again to open the valve, and water is supplied until the output of the pressure sensor 20 reaches a, that is, until it returns to the specified water level H. When the water level returns to the specified level, the water supply is stopped and the drive motor 8 is energized to resume washing and time measurement of time T is resumed. When the time T has elapsed, the drive motor 8 is stopped and the process moves to the next step (drainage step).

(F) Effects of the Invention According to the present invention, when the water level in the washing tub drops from the specified water level H to a certain water level H during washing or rinsing, the rotor blades are automatically stopped once and water is supplied until the water level returns to the specified water level. As a result, washing and rinsing are carried out with a small amount of water, which will not cause severe damage to the fabric, and the drive motor 8 will not be overloaded for a long time or generate heat.
Furthermore, it is possible to prevent deterioration in washing and rinsing performance.

[Brief explanation of the drawing]

The drawings illustrate the present invention; FIG. 1 is a longitudinal sectional view of a washing machine, FIG. 2 is a sectional view showing the structure of a pressure sensor,
Figure 3 is a circuit diagram of the pressure sensor and constant current circuit, Figure 4 is a diagram of the relationship between the water level and the output voltage of the pressure sensor,
FIG. 5 is a block circuit diagram of the washing machine, and FIG. 6 is a flowchart showing the operation of washing and rinsing processes. 5...Washing tub, 18...Air trap, 20
...Semiconductor pressure sensor, 7...Rotor blade, 8...
Drive motor, 40... Water supply solenoid valve (water supply valve), 3
8...Microcomputer (control means).

Claims (1)

[Claims] 1 A semiconductor pressure sensor that detects the air pressure in the air trap that is compressed according to the water level of the washing tub and generates a signal according to the water level, and a semiconductor pressure sensor that receives the signal from the pressure sensor and adjusts the water level of the washing tub during washing or rinsing. A washing machine having a control means for stopping a rotor and opening a water supply valve to supply water to a washing tub up to the specified water level when the water level drops to a certain level below a specified water level.