JPH0522558B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a control device for a washing machine equipped with a turbidity sensor that optically detects the turbidity of washing liquid in a washing tub.

<Prior Art> Many washing machines have already been proposed that are equipped with an optical turbidity sensor to detect the turbidity of the washing liquid in the washing tub and determine the completion of the washing process and the rinsing process.

A typical example of this is that in the detection circuit for the turbidity sensor output, the detection level is automatically set only once at the beginning of the washing process in order to compensate for variations in the turbidity sensor, and thereafter the detection level remains the same until the end of the process. There is a washing machine that performs level detection using the drive current and load current of a turbidity sensor.

However, with this washing machine, if the dirt (hereinafter referred to as turbidity) in the washing liquid changes significantly when heavily soiled laundry is washed, and the turbidity falls outside the detection level of the turbidity sensor, the turbidity will no longer change. The problem was that even if the turbidity could no longer be detected at the detectable level of the turbidity sensor, dirt continued to be discharged, and the turbidity changed significantly, it could no longer be detected as a change in the turbidity sensor's output.

In addition, as another example, a washing machine having means for detecting turbidity during the washing process and the rinsing process using one turbidity sensor by switching the current limiting resistor is disclosed in Japanese Patent Laid-Open No. 57-34895. Disclosed.

This is because the turbidity increases during the washing process and the rinsing process, whereas it decreases during the rinsing process, which is the exact opposite phenomenon. Therefore, the current limiting resistor installed in the turbidity sensor is It is not possible to detect turbidity. Therefore,
A resistor having a specific resistance value for the washing process and a specific resistance value for the rinsing process is provided in the turbidity sensor circuit,
This resistance is switched depending on the process.

However, when considering only the washing process in a washing machine equipped with this turbidity sensor, it is possible to detect turbidity within the specific detection range of the turbidity sensor, but if the turbidity changes further, the former As in the previous example, there was a drawback that it could no longer be detected as a change in the output of the turbidity sensor.

Therefore, in both of the above washing machines, when the turbidity of the washing liquid reaches the detection level of the turbidity sensor, it is determined that the turbidity of the washing liquid is saturated, that is,
It is determined that the stain does not change even after further washing, and it is determined that the washing process is finished. Therefore, when washing laundry that has stubborn stains such as mud or oil, there is a problem in that the washing process ends before the stains are sufficiently removed.

<Purpose> The present invention has been made in view of the above-mentioned drawbacks of the conventional technology.The present invention has been made in view of the above-mentioned drawbacks of the conventional technology. It is an object of the present invention to provide a washing machine control device that can cope with a state that cannot be detected at the detection level of a turbidity sensor.

Therefore, in order to achieve the above object, the present invention determines whether the turbidity of the washing liquid in the washing tub during the washing process has changed significantly and the detection level of the turbidity sensor has reached a saturated state. It has a judgment section and a detection level setting section that sequentially resets the detection range in the washing process when the judgment section judges that the saturated state is reached. The washing machine is provided with a control device having an end determination means for determining the end of the washing process when the washing process has deteriorated or exceeds a final reference value in the final detection range of the turbidity sensor.

Therefore, according to the present invention, if the turbidity of the washing liquid can be detected as a change in the output of the turbidity sensor within the initial setting value, it is determined that the turbidity will not change any further, as in the conventional case, and the washing process is terminated. Make a judgment.

Furthermore, if the turbidity changes significantly and cannot be detected within the set value as a change in the output of the turbidity sensor,
Automatic setting of the detection level is repeated so that the output of the turbidity sensor is equal to or higher than another lower setting value each time. Then, the change in turbidity is tracked and extracted as a change in the output of the turbidity sensor, and when the turbidity is saturated at a certain detection level, it is determined that no more dirt will come out and the washing process is determined to have ended.

Furthermore, if the automatic setting of the detection level is repeated and the turbidity exceeds the final standard value in the final detection range of the turbidity sensor, the turbidity sensor will no longer be able to detect turbidity. The completion of the washing process is determined by .

<Example> An example of the present invention will be described with reference to the drawings. Figure 1 is a block diagram of a fully automatic washing machine.
1 is the fixed outer washing tank, 2 is the liquid inside the tank, 3 is the inner tank,
It rotates during dehydration, and its side and bottom walls are provided with numerous through holes. 4 is a pulsator, inner tank 3
is placed at the bottom of the. 5 is a communication pipe; 6 is a communication pipe for draining the tank liquid 2 through the drain valve 7;
It is connected to the bottom of the outer tank 1.

The lower part of the communication pipe 6 is connected to the lower part of the communication pipe 5, and the upper part of the communication pipe 5 is connected to the side of the outer tank 1, thereby forming a circulation path for the tank liquid 2. . Se is a turbidity sensor placed in the circulation path.

8 is a pulsator motor, and 14 is a microcomputer-made control circuit for controlling the pulsator motor 8, the turbidity sensor Se, and the drain valve 7. In the control circuit 14, 9 is a motor control section;
1 is a detection level setting unit that switches the drive current and load current of the turbidity sensor Se, 12 is a drain valve control unit, and 13 is a judgment unit composed of a microcomputer.

Here, the determination unit 13 transmits signals for selection sequence control to the motor control unit 9 and the drain valve control unit 1.
2 and a water supply valve control unit (not shown); and a turbidity sensor that receives the output of the turbidity sensor Se from the detection level setting unit 10.
A determination means for determining whether the detection level of Se has reached a saturated state, and a determination means for determining whether or not the output of the turbidity sensor is finished when the output becomes constant or exceeds a final reference value in the final detection range, and the driving is performed. Completion determining means for stopping the driving of the control means is provided.

The above-mentioned saturation state of the detection level means that the judgment unit 1
This refers to the range in which the electrical accuracy of the voltage level judgment function described in step 3 deteriorates (the range greater than V1' or smaller than V0' in Fig. 4), and this range is input to the judgment means as a preset value. I'll keep it. The detection level setting section 10 includes a judgment section 13.
Turbidity sensor based on the judgment result from the judgment means of
It has a function of switching the drive current and load current of Se and repeatedly automatically setting the detection level so that the output of the turbidity sensor Se becomes equal to or higher than another set value.

In the configuration shown in FIG. 1, the pulsator 4 rotates at the same time as the motor 8 rotates, so that the tank liquid 2 is transferred from the inner tank 3 to the outer tank 1 to the communication pipe 5 as shown by the arrow in the figure.
→ Conducting pipe 6 → hole at the bottom of inner tank 3 → inner tank 3 and circulates.

Next, turbidity sensor Se and detection level setting section 1
To explain 0 in detail with reference to FIG. 3, the turbidity sensor Se consists of a light emitting element LED that emits light into the tank liquid 2 by a drive current, and a light receiving element PT that receives the transmitted light and outputs a detection electric signal. There is.
In this example, the light receiving element PT is a phototransistor, which is provided on the outside of the conductive tube 6 to face each other with its transparent portion interposed therebetween, and optically detects the turbidity of the liquid 2 in the tank.

R1, R2, R3 are the drive current If of the light emitting element LED
The limiting resistor Tr1 is a transistor array, and the output signal from the judgment unit 13 is connected to terminals a, b,
If the “H” signal is input to these terminals, the resistors R1, R2,
Apply current to R3.

By setting the resistance values of resistors R1, R2, and R3 to different values, 2 ³ - 1 = 7 combinations of combined limiting resistances Rx can be set by combining the "H" signals input to terminals a, b, and c. . Resistance R4, R5, R
6 is a load resistor that limits the load current Ic of the photodetector PT, Tr2 is a transistor array, and the judgment unit 13
When the output signals from the
A current is passed through the resistors R4, R5, and R6 corresponding to the current.
By setting the resistance values of resistors R4, R5, and R6 to different values, 2 ³ −1 = 7 combinations of the “H” signals input to terminals d, e, and f can be created.
can be set.

The DC power supply voltage on the light emitting side is V1, and the resistors R1,
If the combined limiting resistance of R2 and R3 is Rx, drive current If = (V1 - Vf - Vs) / Rx, where Vf is the forward voltage drop of the light emitting element LED, and Vs is the output saturation voltage of the transistor array Tr1.

The DC power supply voltage on the light receiving side is V2, and the resistor R4,
When the combined load resistance of R5 and R6 is Rz, the load current Ic = (V2-Vc-Vs')/Rz However, Vc is the collector voltage of the photodetector PT,
Vs' is the output saturation voltage of transistor array Tr2.

The detection level output voltage from the detection level setting section 10 to the determination section 13 is expressed as Vout voltage, Vout=V2-Vc.

In the embodiment shown in FIG. 3, three current limiting resistors and three load resistors are used.
If there are m books, there are 2 ⁿ −1 combination limiting resistances.
Rx, 2 ^m −1 combined load resistance Rz can be set.

Furthermore, it goes without saying that the light emitting part and the light receiving part of the turbidity sensor Se can be used in common as a DC power source.

In the light receiving element PT, when the amount of light received is constant, the collector current (load current) Ic and collector voltage Vc are proportional, and when the collector current Ic is constant, the amount of received light and the collector voltage Vc are inversely proportional. Photodetector PT
The amount of light received is proportional to the drive current If of the light emitting element LED,
It is inversely proportional to the turbidity of the tank liquid 2.

To explain this relationship based on FIG. 2, first, in a certain turbidity state,
The drive current If and the collector current Ic are set by and the composite load resistance Rz, and Ic=I1, Vc=V
1 (point P in FIG. 2). At this time, when the turbidity and If are constant and Ic is changed, Vc moves on the line of curve A. Next, from the state of point P, if
and Ic are constant, and when the turbidity changes, Vc moves on the line of curve D.

As the washing process progresses, dirt is discharged and the turbidity changes significantly to reach Vc = V0 (point Q in Figure 2), and if and Ic are changed by the resistances Rx and Rz. Reset Ic=I2, Vc=V1
(point R in Figure 2). Furthermore, when the turbidity changes significantly, Vc moves on the line of curve E, and when it reaches Vc = V0 (point S in Figure 2), it repeats again, Ic = I3, Vc = V1 (second The settings are made so that the point (T point in the figure) is reached.

FIG. 4 illustrates the above contents based on the relationship of V2-Vc=Vout. FIG. 5 is a flowchart illustrating the operation of the washing process of the fully automatic washing machine of the present invention.

Below, the process will be explained based on Figs. 4 and 5. Since the turbidity at the start is small, the detection level detection voltage by the light receiving element PT of the turbidity sensor Se is
Vout decreases. Time t1 (point Y in Figure 4)
Then, the detection level setting section 10 and the judgment section 13 set If and Ic based on the resistances Rx and Rz, and
Initial setting is performed so that Vout=V1'(V1' is the first setting value) (point P in FIG. 4 and STEP 1 in FIG. 5).

As the washing process progresses, the change in turbidity is small.
If the turbidity is saturated within the initially set detection level and can be detected as a change in the output of the turbidity sensor, it is determined that the turbidity will not change even if the washing process is continued any longer, and the washing process is stopped. Completion is determined (STEP 2 in FIG. 5).

However, as the washing process progresses and the turbidity changes significantly, the determination unit 13 determines whether or not the turbidity exceeds the turbidity sensor detection range, until Vout=V0' is reached (see Figure 4). between P and Q) continues as it is (STEP 3 in Figure 5), but Vout=
When V0'(V0' is the second set value) is reached (point Q in Figure 4), the setting is performed again and Vout=V1' (the fourth set value).
Point R in the figure and STEP 4) in Figure 5.

After that, the turbidity changed even more significantly and Vout=V
The setting is repeated so that Vout=V1' each time it becomes 0'.

The number of times this setting is repeated is counted by the logic circuit of the determining section 13, and the turbidity level is evaluated from this number of times and the output Vout from the detection level setting section 10.

Then, when the change in turbidity decreases within the detection level range and the turbidity reaches a saturated state, which is detected as a change in the output of the turbidity sensor, it is determined that the washing process is complete (STEP 2 in FIG. 5).

Note that the turbidity sensor in the above embodiment has R1, R2, and R3 on the light emitting side and R on the light receiving side as shown in Fig. 3.
4, R5, and R6, each having a different value, a turbidity sensor with 49 detection levels can be created by switching and combining these resistances.

Therefore, if the detection level setting has been changed more than 49 times, that is, if the final reference value in the final detection range of the turbidity sensor is exceeded, even if the turbidity changes further, the turbidity sensor will not Since turbidity cannot be detected, it is determined that the washing process has ended (STEP 5 in FIG. 5).

As described above, in the present invention, the voltage range in which the electrical accuracy of the voltage level determination function of the detection level setting section 10 and the determination section 13 is the best (V0'≦
Vout≦V1'), therefore, even if the turbidity changes significantly (dotted line curve G in FIG. 4), the turbidity can be accurately detected without becoming saturated.

Note that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that many modifications and changes can be made to the above-mentioned embodiments within the scope of the present invention.

For example, the light emitting element LED and the light receiving element PT of the turbidity sensor Se may be provided inside the conduction tube 6 as long as waterproof measures are taken, or they may be provided in an immersed part other than the conduction tube 6. Furthermore, the turbidity sensor Se can be used not only in the washing process but also in the rinsing process.

<Effects> As is clear from the above explanation, according to the present invention, turbidity can be detected in the voltage range in which the electrical accuracy of the voltage level judgment function circuit of the judgment section is the best in each same process, so the detection accuracy is high. Furthermore, even if the turbidity changes significantly and reaches a saturated state, the turbidity can be tracked and accurately detected. Therefore, there is an excellent effect that a more accurate termination judgment can be made based on this.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a fully automatic washing machine according to an embodiment of the present invention, Fig. 2 is a characteristic diagram of a phototransistor which is an example of the light receiving element of the turbidity sensor, and Fig. 3 is a diagram of the characteristics of a phototransistor which is an example of the light receiving element of the turbidity sensor. The electronic circuit diagram of the detection level setting section, Fig. 4 is a diagram showing the output voltage of the turbidity sensor during the washing process, and Fig. 5 is a flowchart explaining the operation of the washing process of the fully automatic washing machine. . LED: Light emitting element, PT: Light receiving element, Se: Turbidity sensor, If: Drive current, Ic: Load current, 1: Fixed outer washing tank, 2: Liquid inside the tank, 3: Inner tank, 4: Pulsator, 5 : Communication pipe, 6: Conduction pipe, 7: Drain valve,
8: Pulsator motor, 9: Motor control section, 1
0: Detection level setting section, 12: Drain valve control section, 1
3: Judgment unit, 14: Control circuit.

Claims (1)

[Claims] 1. A washing machine that automatically performs at least a washing process and a rinsing process, and is equipped with a turbidity sensor that is equipped with a light emitting element and a light receiving element so as to project light through the washing liquid in the washing tub, and detects the amount of light emitted by the light emitting element or the light receiving element. In a washing machine control device which has a means for switching the ratio of the amount of light received and controls the completion of a washing process or a rinsing process based on the output of the turbidity sensor, the washing machine control device has a means for switching the ratio of the amount of light received by the turbidity sensor. a determination unit that determines whether the detection level of the turbidity sensor has reached a saturated state due to a change; and a detection level that sequentially resets the detection range in the washing step when the determination unit determines that the detection level is saturated. a setting unit, and the determining unit includes an end determination unit that determines the end of the washing process when the output of the turbidity sensor becomes constant and exceeds a final reference value in the final detection range of the turbidity sensor. A control device for a washing machine, characterized in that it has means.