JPH0337437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a water supply state determination device for a washing machine.
More specifically, the present invention relates to a device that determines the balance between the amount of laundry and the amount of water supplied.

``Prior Art'' In a washing machine, it is natural that the amount of laundry and the amount of water supplied should be balanced. If the amount of water supplied is too low, the laundry will be damaged and cannot be washed satisfactorily.
Too much water, detergent, electricity, etc. will be wasted.

Therefore, it is necessary to know the balance between the amount of laundry and the amount of water supplied, but there is no known device that can detect such a balance.

Therefore, the amount of water supplied to conventional washing machines is currently determined appropriately based on the operator's experience.

By the way, there is a device called an automatic water supply device, and a typical example of such a device is to supply water to a washing tub up to a predetermined low water level and operate a washing motor.
The steady value of the input current of the washing motor is measured, and depending on the magnitude, the amount of laundry is determined into three levels: small, medium, and large. Depending on the determination, the water level is set to low or low.
The amount of water supplied is determined to be either medium or high. In this method, the amount of laundry is estimated from the amount of load on the washing motor, and the amount of water to be supplied is determined accordingly.

``Problem to be solved by the invention'' When determining the amount of water to be supplied to the laundry based on the operator's experience, there is a problem that objective accuracy cannot be expected.

In addition, when using the automatic water supply device of the above conventional example,
There is a problem in that it is not always possible to accurately estimate the amount of laundry because the load on the washing motor varies depending on the type of laundry.

Therefore, the present invention aims to solve such problems.
The present invention aims to provide a device that can directly and accurately detect the balance between the amount of laundry and the amount of water supplied.

"Structure of the Invention" The water supply state determination device for a washing machine of the present invention includes a water level increase rate detection means for detecting the rate of increase in the water level in the washing tub of the washing machine as water is supplied into the washing tub; The amount of laundry and the amount of water supplied are determined when the rate of increase in the water level detected by the agitation means that stirs the inside of the washing tub to hydrate the laundry when the rate detection means is activated and the rate of increase in the water level detected by the water level increase rate detection means reaches a predetermined value. This system is characterized in that it is equipped with water supply criticality determination means for determining whether the water supply criticality is balanced and outputting a criticality signal.

"Function" The inventors of the present invention studied how the water level increases when water is supplied at a constant rate to a washing tub filled with laundry, and found a peculiar phenomenon as shown in Figure 4. It was discovered that the characteristics of

That is, in FIG. 4, a represents the water level increase characteristic when the amount of laundry is small. The reason why the water level is accompanied by a small amplitude is that a so-called water pump effect occurs due to the intermittent stirring. Similarly, b represents a medium amount of laundry, and c represents a large amount of laundry. Moreover, s represents the case where water is simply supplied to the washing tub without stirring or adding laundry (referred to as simple water supply).

As can be understood from the water level change curves a, b, and c, the water level increase characteristic when laundry is loaded shows characteristics consisting of the following three regions, regardless of the amount of laundry.

In the initial stage of water supply, the increase in water level is slower than that in the case of simple water supply. In other words, the rate of increase is small.

When water is supplied to a certain extent, the water level increases faster than the increase s in the case of simple water supply. In other words, the rate of increase is large.

Eventually, the water level will increase at the same rate as the increase s in the case of simple water supply. That is,
The increase rate is the same as in the case of simple water supply.

The above characteristics are the water level change curve a,
The curve a′ in Figure 5 is drawn by connecting the maximum values of b and c.
It will be understood more clearly if we refer to b' and c'.

Here, it is thought that in the above region, since the supplied water is absorbed by the laundry, the increase in water level appears less than in the case of simple water supply.

Next, in the above region, the absorption of water into the laundry is saturated, and the supplied water appears as an increase in the water level, but the cross-sectional area of the washing tub is substantially reduced due to the presence of the laundry. Therefore, it is thought that the water level will rise faster than in the case of simple water supply.

In the above region, the amount of water increases compared to the amount of laundry, and the effect of the reduction in the cross-sectional area of the washing tub due to the laundry is lost, and the water level is thought to rise at the same rate as in the case of simple water supply. .

Therefore, if we focus on when the rate of increase in the water level in the washing tub shifts from an area where it is greater than the rate of increase in the case of simple water supply to an area where it is equal to the rate of increase in the water level in the case of simple water supply, we can determine whether the laundry is submerged below the water surface or It is thought that the amount of water rises from the bottom of the washing tub, and this is considered to be the water supply critical point where the amount of laundry and the amount of water supplied are balanced.

Since this condition is directly determined by the amount of laundry, it is possible to accurately determine the balance between the amount of laundry and the amount of water supplied without being affected by the type of laundry.

Note that for washing, it is necessary to continue the water supply until at least the water supply criticality described above, but after that, the water supply may be stopped immediately after the water supply criticality is reached, or the water supply may be stopped after a certain delay. This is because the proportion of water suitable for washing differs slightly depending on the type of cloth.

"Example" The present invention will be described in more detail below based on the example shown in the drawings. Here, FIG. 1 is an explanatory diagram of the configuration of a washing machine equipped with an embodiment of the water supply status determination device of the present invention, FIG. The figure is a flowchart showing water supply status determination and water supply control processing in the washing machine shown in Fig. 1, Fig. 4 is a water level change characteristic diagram, and Fig. 5 is a diagram connecting the maximum values of the water level change characteristics shown in Fig. 4. The drawn water level change characteristic diagram, FIG. 6, is a characteristic diagram showing changes in the rate of increase in the water level change characteristic diagram shown in FIG. Note that the present invention is not limited to this example.

A washing machine 1 shown in FIG. 1 basically includes a water supply valve 2, a water level sensor 3, a washing tub 4, a water tub 5, a pulsator 6, a drive mechanism 7, a motor 8, and a control circuit 10.

Here, other components except for the control circuit 10 are the same as corresponding conventionally known components. The control circuit 10 is different from the conventional one in that it functions as a water supply status determination device according to the present invention.

As shown in FIG. 2, the water level sensor 3 is, for example, a semiconductor strain gauge type pressure sensor, and changes its resistance value depending on the water level.

The change in resistance value is output by the amplifier circuit 11 of the control circuit 10 as a water level signal d.

The water level signal d is input by the peak hold circuit 12 of the control circuit 10 to the microcomputer 13 as a peak hold value e.

The microcomputer 13 reads the operator's instructions via the operation unit 14 . It also controls the water supply valve 2 and motor 8. Furthermore, the peak hold value e output by the peak hold circuit 12 is read, and the peak hold circuit 12 is cleared for the next peak hold.

Next, with reference to FIG. 3, the water supply state determination and water supply control processing in the washing machine 1 will be described.

When the operator puts the laundry Q into the washing tub 4 and gives an instruction to supply water from the operating section 14, the microcomputer 13 enters the process shown in FIG. 3.

First, the microcomputer 13
Open and start water supply (S1).

Next, the time span for calculating the rate of increase in water level
Set _Td (S2).

Next, clear the peak hold circuit 12,
Prepare for a new peak hold (S3).

Next, a time T _p for turning on the motor 8 is set (S4), the motor 8 is driven for the set time T _p (S5) (S6) (S7), and a time for turning the motor 8 off.
T _f is set (S8), and the motor is stopped for that time T _f (S9).

Driving the motor 8 for the time T _p and stopping the motor 8 for the time T _f are repeated and continued for the time T _d to promote water absorption in the laundry (S10).

When the time T _d has elapsed, the peak hold value e is read since the peak hold circuit 12 holds the maximum value of the water level during that time (S1
1).

Next, the read peak hold value e,
Difference ΔB between the previous memorized peak hold value e
is calculated (S12).

Once the difference ΔB, that is, the increase ΔB, is calculated, divide the increase ΔB by the time width T _d to calculate the increase rate ΔB/T _d
is calculated (S13).

The variation of the increase rate ΔB/T _d obtained here with respect to the water supply time T is as shown in FIG. In other words, simple water supply, small to medium amount of laundry,
Corresponding to a large amount, s″, a″, b″, and c″ each exhibit changing characteristics, but in the case of simple water supply, the rate of increase ΔB/T _d is constant. When the amount of laundry is small, medium, and large, the rate of increase converges to the rate of increase when the water supply reaches a certain point, that is, the critical water supply time.

Therefore, it would be better to compare the increase rate ΔB/T _d with the preset increase rate in the case of simple water supply.
Taking into account the variation, the predetermined range s ₁ ~
When it is at _s2 , it is determined that the increase rate ΔB/ _Td has become the increase rate of simple water supply (S14).

Also, when moving from the above region to the region, the transient increase rate ΔB/T _d matches the increase rate in the case of simple water supply, so in order to ignore this, nothing is done in the first match. , it is determined that the water supply becomes critical for the second time (S15).

Instead of doing this, changes in the rate of increase ΔB/T _d may be checked, and water supply criticality may be determined when the rate of increase B/T _d decreases and matches the rate of increase of simple water supply.

If it is determined that the water supply is critical, turn off the water supply valve 2,
Water supply is stopped (S16).

As a result of the above, the water supply is stopped, but the amount of water supplied at this time is limited to the amount that the laundry is soaked in water.
It is in perfect condition for normal washing. However, as described above, more water may be supplied if desired.

As another example, instead of calculating the rate of increase of the maximum value of the water level as described above, the rate of increase of the minimum value of the water level is calculated, or the rate of increase of the average value of the maximum value and the minimum value of the water level is calculated. Examples include those in which stirring is calculated, and those in which stirring is not intermittent.

In yet another embodiment, in a washing machine in which the water supply valve 2 does not automatically open and close, a buzzer, LED, or other display means indicates that the water supply has become critical, prompting the operator to stop the water supply. Things can be mentioned.

"Effects of the Invention" According to the present invention, there is provided a water level increase rate detection means for detecting the rate of increase in the water level in the washing tub as water is supplied into the washing tub, and when the water level increase rate detection means is activated. When the rate of increase in the water level detected by the agitation means to hydrate the laundry by agitation and the rate of increase in water level detected by the water level increase rate detection means reaches a predetermined value, it is determined as water supply criticality where the amount of laundry and the amount of water supplied are balanced, and a critical signal is generated. Provided is a water supply status determination device for a washing machine, which is characterized by comprising water supply criticality determination means that outputs a Regardless of the type, it becomes possible to objectively and accurately discriminate.

Therefore, no matter the amount of laundry, the optimum amount of water can be supplied, preventing damage to the laundry, and eliminating waste of water, electricity, etc.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a washing machine equipped with an embodiment of the water supply status determination device of the present invention, FIG. 2 is a circuit diagram of a main part of the water supply control section of the washing machine shown in FIG. 1, and FIG. Fig. 1 is a flowchart showing water supply status determination and water supply control processing in a washing machine, Fig. 4 is a water level change characteristic diagram, and Fig. 5 is drawn by connecting the maximum values of the water level change characteristics shown in Fig. 4. Water level change characteristic diagram, No. 6
The figure is a characteristic diagram showing changes in the rate of increase in the water level change characteristic diagram shown in FIG. (Explanation of symbols), 1...Washing machine, 2...Water valve,
3... Water level sensor, 4... Washing tub, 8... Motor, 10... Control circuit, 12... Peak hold circuit, 13... Microcomputer, S13...
...Increase rate calculation process, S14, S15... Water supply criticality determination process.

Claims (1)

[Scope of Claims] 1. Water level increase rate detection means for detecting the rate of increase in water level in the washing tub of a washing machine as water is supplied into the washing tub;
When the water level increase rate detected by the agitation means which stirs the inside of the washing tub to hydrate the laundry when the water level increase rate detection means is activated and the water level increase rate detected by the water level increase rate detection means reaches a predetermined value, the amount of laundry is determined. A water supply state determination device for a washing machine, comprising a water supply criticality determination means for determining the water supply criticality at which the water supply amount is balanced and outputting a criticality signal. 2. The water supply state determination device for a washing machine according to claim 1, wherein the stirring means intermittently stirs the inside of the washing tub when the water level increase rate detection means is activated.