JPH07255985A - Water level sensing method for electric washing machine - Google Patents

Abstract

PURPOSE:To detect a water level in a stable manner even if there are, during operation of a washing machine, incoming noise and influence due to a water current caused by a pulsator and that of feeding and discharging of water from the outside. CONSTITUTION:When water level data from a water level sensor 1 are always inputted into an operation device of a control circuit 2 to sense a water level, water level is determined using the remainder of the water level data excluding a maximum value and a minimum value thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a water level detecting method for an electric washing machine in which the water level is automatically controlled by an input signal from a water level sensor.

[0002]

2. Description of the Related Art There are the following types of automatic electric washing machines.

First, there is one washing tub as shown in FIGS. 1 and 2 of JP-B-5-36070. In this case, a separate dehydration tank is required.

Next, in order to perform washing, rinsing and dehydration fully automatically, there is a washing tub having two tubs, an inner tub and an outer tub (hereinafter referred to as a fully automatic washing machine). This is as follows depending on the structure of the inner tank.

FIG. 10 (a) is a schematic cross-sectional view of a fully automatic washing machine in which an inner tub 12 having holes all around it is provided inside the outer tub 8. During washing and rinsing, water is stored in the entire outer tub 8 up to the water level indicated by the dotted line, and the pulsator 1 at the bottom of the inner tub 12 is stored.
1 is periodically inverted by a motor (not shown) to wash or rinse. At the time of dehydration, the inner tank 12 is rotated, and it is dehydrated by a centrifugal force through a hole formed on the entire side surface thereof. The water is drained via the drain valve 4. The pressure in the air trap 10 changes due to the change in the water level in the outer tub 8, and the change in pressure is transmitted through the pressure guiding pipe 9, and the water level sensor 1 detects the water level.

FIG. 10B is a graph showing the relationship between the ON / OFF signal of the motor and the pressure when the pulsator 11 rotates.

FIG. 11A shows a conical inner tank 12-1.
It is a schematic sectional drawing of the fully automatic washing machine which provided. In this case, the outer tank 8-1 has the same shape as the outer tank 8 of FIG.
2-1 has a cone shape with an inclination so that the inner diameter increases from the lower side to the upper side, and a drainage hole is provided around the upper part of the inner tank. Inner tank 1 for washing and rinsing
Water is stored up to the water level indicated by the dotted line only in 2-1 and the pulsator 11 is rotated for washing and rinsing. At the time of dehydration, the inner tank 12-1 is rotated, and the water is drained by a centrifugal force from a hole provided around the upper portion thereof. This method has the advantage of using less water. The same parts as those in FIG. 10A are denoted by the same reference numerals.

In this case, since water is not stored in the outer tank 8-1, a drainage channel is formed on the outer side of the rotating shaft for rotating the inner tank 12-1 at the time of dehydration, coaxially with the rotating shaft, and a part of this drainage channel is formed. The air trap 10 is formed.

FIG. 11B is a graph showing the relationship between the ON / OFF signal of the motor and the pressure when the pulsator rotates in this case. Since the air trap 10 is directly connected to the inner tank 12-1 via the drainage channel, the force applied when the pulsator rotates is large and the pressure change is large.

In the system of FIG. 10 (a), the force applied when the pulsator rotates is buffered in the inner tank and then applied to the air trap, so that the pressure change applied to the air trap is different from that in the case of FIG. 11 (a). Is small.

FIG. 7 is a block diagram of a water level detection circuit of an electric washing machine which automatically controls the water level according to an input signal of the water level sensor. The water level data of the washing tub is constantly input to the control circuit 2 from the water level sensor 1, the microcomputer 5 which is an arithmetic unit in the control circuit 2 calculates an average value of the water level data, and the water level is detected and the water supply valve is supplied from the microcomputer 5. ON-OFF of 3 and ON-OF of drain valve 4
The water level was controlled by outputting the F signal. The microcomputer 5 also controls the rotation of the motor 15. FIG. 8 is a flow chart of a program for water level determination by the microcomputer 5 of the apparatus of FIG. In step S51, the water level data at a predetermined time interval is read, in step S52 the average value is calculated, and in step S5
The water level is determined in 3 and the water level is determined in step S54. In this method, the water level data is constantly stored in the microcomputer 5.
When there is a large change in the water level associated with the generation of a water flow driven by the motor, there is a problem that the water level corresponding to the actual water amount cannot be detected.

As a modification of the above-mentioned method, Japanese Patent Publication No. 5-360
Some of them, like No. 70, carry out stable water level control by reading water level data only when the motor is stopped by reversal control. FIG. 9 is a flowchart of the program for water level determination. In step S61, it is determined whether the motor is rotating. If the motor is not rotating, step S61 is performed.
The water level data is read at 62, the average value is calculated at step S63, the water level is determined at step S64, and step S6 is performed.
Determine the water level at 5.

According to the invention of Japanese Examined Patent Publication No. 5-36070, the water level determination is performed while the motor is stopped by the reversal control during the washing machine operation using the water level determination timing determining device, so that the influence of the water level fluctuation due to the motor drive is affected. Can be reduced and more accurate water level detection can be performed.

[0014]

If the method of inputting the water level data when the motor is stopped is used, the influence of the water flow is reduced, but because of the influence of the water supply and drainage from the outside other than the water supply valve and the drain valve. The water level is erroneously detected and, for example, operation is started even if the water level has not reached the specified water level, or water is supplied even though the water level is the specified water level, resulting in waste of water or damage to the cloth.

It is desirable that the water level can always be detected during operation of the washing machine. Therefore, when inputting the water level data at all times, the external noise and the pulsator when the motor is driven are added to the water level data for a fixed time for judging the water level. There is the influence of the water flow generated by.

When the inner tank is conical, the change in pressure during rotation of the pulsator is large compared to the case where the inner tank is not conical.

The object of the present invention is to prevent the water level from being erroneously detected even when there is an influence of external noise, water flow by a pulsator, and water supply / drainage from the outside while the washing machine is in operation.
It is to obtain a water level detection method that can always perform stable water level detection.

[0018]

In the water level detection method of the present invention, the water level data is constantly input to the arithmetic unit of the control circuit, and unnecessary water level data affecting the water level determination is excluded from the calculation. .

[0019]

[Operation] Even if external noise comes into the water level data during operation of the washing machine, the external level can be determined by determining the water level from the remaining water level data excluding the maximum and minimum values of the water level data for a certain period of time. Stable water level detection that is not affected by noise can be performed. Further, even if the water level data is constantly input, by not using the water level data while the motor is driven, stable water level detection can be performed without being affected by the water flow of the pulsator. Also, when there is a sudden change in water level due to water supply / drainage from the outside, stable water level detection can be performed by not using the water level data. Further, when there is a sudden change in water level, more stable water level detection can be performed by performing water level determination from the water level data after a fixed time after the change has subsided.

[0020]

1 is a schematic cross-sectional view of an electric washing machine for carrying out the method of the present invention. This is for a fully automatic washing machine of the type shown in FIG.

In FIG. 1, the water level sensor 1 provided on the operation panel 7 of the outer casing 6 for detecting the water level in the outer tank 8 is
A pressure guiding pipe 9 is connected to an air trap 10 provided at a lower portion of the outer tank 8. This operation will be described later. At the lower part of the outer tub 8, a reduction mechanism 13 for rotating the pulsator 11 and the inner tub 12 and a motor 15 connecting the same with a V-belt 14 are provided.

Reference numeral 3 is a water supply valve, and 4 is a drain valve, both of which are opened and closed by the output of an ON-OFF signal from the control circuit 2 to control the water level.

In the water level sensor 1, the pressure in the air trap 10 changes due to the change in the water level in the outer tub 8, and the pressure change is transmitted through the pressure guiding pipe 9 to the control circuit 2 through the water level sensor 1.
To the water level, the water level is determined by an arithmetic device such as a microcomputer provided therein, and the water supply valve 3 and the drain valve 4 are opened and closed by the output of an ON-OFF signal from the microcomputer, and the water level in the outer tank 8 is Is controlled. A block diagram of a relevant portion of the control circuit 2 is similar to that of FIG.

FIG. 2 is a flow chart of the program of the microcomputer in the first embodiment. From the time when the user starts the operation program through the operation panel 7, n pieces of water level data are constantly and continuously read from the water level sensor 1 at a fixed time and are input to the microcomputer in the control circuit 2 (step S11). ), The maximum (Max) value and the minimum (Min) value out of n pieces of water level data for a fixed time for performing water level determination are not adopted as data (step S12), and the average value of other n−2 pieces of data Is calculated (step S13) to determine the water level (step S14) and determine the water level (step S1).
Perform 5). It is also possible to remove adjacent values of data, including maximum and minimum values. By performing the above processing, it is possible to prevent erroneous detection of the water level due to the influence of external noise and the like, and it is possible to perform stable water level detection.

FIG. 3 is a flow chart of the program of the microcomputer according to the second embodiment. Since the user started the operation program with the operation panel, the water level data from the water level sensor 1 is read,
These are constantly input to the microcomputer in the control circuit 2 (step S21). After reading this water level data, confirm ON / OFF of the motor (step S2
2) The average value of the water level data is calculated only when the motor is off (step S23), and the water level determination (step S24) and the water level determination (step S25) are performed.
By performing the above processing, stable water level detection can be performed without being affected by the water flow by the pulsator when the motor is turned on. Since the water level data is constantly input, the water level determination timing determining device provided between the motor control device and the microcomputer, which is required in Japanese Patent Publication No. 5-36070, becomes unnecessary.

The final water level determination and water level determination steps of the first and second embodiments can be combined into one step.

FIG. 4 is a flow chart of a program of the microcomputer of the third embodiment. The user reads the water level data from the water level sensor 1 from the time when the operation program is started by the operation panel, and constantly inputs the data into the microcomputer in the control circuit 2 (step S31). The average value of the water level data for this fixed time is calculated (step S32), the water level is determined (step S33), and the determined value is compared with the previously determined water level value (step S34). When the absolute value of is greatly exceeded the set value as shown in FIG. 6, the water level is determined not to be adopted (step S3).
5). By performing the above processing, even if there is a sudden change in the water level due to water supply / drainage from the outside other than the water supply valve 3 and the drainage valve 4, it is possible to perform stable water level detection without erroneously detecting the water level. .

FIG. 5 is a flow chart of the program of the microcomputer in the fourth embodiment of the present invention. Steps S41 to S43 are the same as steps S31 to S33 of the third embodiment. When there is a sudden change in water level as in the third embodiment (step S44) after the change in water level has subsided, the water level data within the set fixed time is not adopted (step S45). In this way, it is possible to eliminate the influence of the water flow generated after the water supply and drainage from the outside, and to perform stable water level detection.

It is needless to say that each of the programs described above can be used for a washing machine for a conical inner tub of the type shown in FIG. 11 or a washing machine as described in Japanese Patent Publication No. 5-36070.

[0030]

As described above, according to the present invention, by removing the maximum value and the minimum value of the water level data, the water level can be detected without being affected by external noise and the like.

By not adopting the water level data when the motor is ON, the water level can be detected without being affected by the water flow by the pulsator.

By not using the water level data when there is a sudden change in water level, the water level can be detected without being affected by external water supply and drainage. Further, at this time, by not using the water level data for a fixed time after the water level change has subsided, the water level can be detected more reliably without being affected by the water flow generated by the water supply and drainage from the outside.

As described above, for example, the operation is not started even when the water level does not reach the specified water level, and the water supply is not continued even though the water level is the specified water level. Therefore, the water is wasted and the cloth is damaged. Can be prevented.

Since the water level can be detected for all the washing courses, the water level can be changed by changing the course during operation, and water can be supplied by absorbing water in the cloth.

The effect is particularly great when the inner tank is conical.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an example of a washing machine embodying the present invention.

FIG. 2 is a flow chart of the first embodiment of the present invention.

FIG. 3 is a flowchart of a second embodiment of the present invention.

FIG. 4 is a flow chart of a third embodiment of the present invention.

FIG. 5 is a flow chart of a fourth embodiment of the present invention.

FIG. 6 is a graph showing a relationship between a set value of pressure related to water level and water level.

FIG. 7 is a block diagram of a conventional water level detection method.

FIG. 8 is a flowchart of an example of a conventional water level detection method.

FIG. 9 is a flowchart of another example of a conventional water level detection method.

10A is a schematic cross-sectional view of an example of a fully automatic washing machine, and FIG. 10B is a graph of pressure change due to ON-OFF of a motor.

FIG. 11A is a schematic cross-sectional view of another example of the fully automatic washing machine, and FIG. 11B is a graph of pressure change due to ON-OFF of the motor.

[Explanation of symbols]

 1 Water Level Sensor 2 Control Circuit 3 Water Supply Valve 4 Drain Valve 6 Outer Casing 7 Operation Panel 8 Outer Tank 9 Pressure Pipe 10 Air Trap 11 Pulsator 12 Inner Tank 13 Reduction Mechanism 14 V Belt 15 Motor

Claims (5)

[Claims] 1. An electric washing machine for automatically determining the water level by continuously inputting the water level data in the washing tub by the water level sensor to the arithmetic unit of the control circuit continuously during the operation of the washing machine. In the water level detection method of, the water level of the electric washing machine is characterized in that the water level is determined by a computing device using the remaining water level data excluding the maximum value and the minimum value of the water level data for a fixed time for performing the water level determination. Detection method. 2. The water level detecting method for an electric washing machine according to claim 1, wherein the water level data while the motor is rotating is not adopted in the arithmetic unit. 3. A water level of an electric washing machine for automatically controlling the water level by continuously inputting the water level data in the washing tub by the water level sensor to the arithmetic unit of the control circuit during the operation of the washing machine. In the detection method, when the difference between the water level determined this time and the water level determined last time exceeds the set value due to a sudden change in water level, the water level determined this time is not adopted in the arithmetic unit. How to detect the water level of a machine. 4. The water level determination is performed based on water level data after a lapse of a fixed time after the difference between the previously determined water level and the currently determined water level falls within a set value range.
A method for detecting the water level of an electric washing machine as described. 5. The water level detecting method for an electric washing machine according to claim 1, 2, 3 or 4, wherein the inner tub of the washing tub is conical.