JPH0417078B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a washing machine cloth amount detection device that uses ultrasonic waves to detect the amount of cloth in a washing machine.

BACKGROUND ART Conventionally, there are known washing machines that use ultrasonic waves to detect the amount of cloth and automatically set the water level of the washing machine.

Problems to be Solved by the Invention However, with this conventional device, if the ultrasonic element is damaged, it is naturally impossible to accurately detect the amount of cloth and it is not possible to set an appropriate water level. In other words, there are situations in which only a small amount of water is required even though there is a large amount of cloth, and there are situations in which a large amount of water is required even though there is a small amount of cloth. However, from the point of view of washing in a washing machine, if there is little water, the fabric will become damaged, which is a problem, but if there is a lot of water, there will be no problem in terms of washing, except that it will not save water.

In view of this point, the present invention is designed so that even if the ultrasonic element is damaged, there is no problem in using the washing machine.

Means for Solving the Problems In order to solve the above problems, the present invention includes: an ultrasonic element installed above the washing tub to detect the amount of cloth; a water level sensor to detect the water level in the washing tub; A water supply valve that supplies water to the washing tub; and a control device that controls the ultrasonic element, the water level sensor, and the water supply valve; It has an element abnormality detection means and a high water level setting means for setting the water level to the highest water level when the abnormality is detected, and the high water level setting means is configured to control the water supply valve with the output from the water level sensor.

Effect: With the above configuration, if the ultrasonic element becomes abnormal, the water level is automatically set to the highest water level, and washing can be carried out without damaging the cloth, regardless of whether the amount of cloth is large or small.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an ultrasonic element that detects the amount of cloth, 2 is a water supply valve that supplies water to the washing tub 5, and 3 is a water level sensor that detects the water level of the washing tub 5. The ultrasonic element 1, water supply valve 2, and water level sensor 3 are connected to and controlled by a control device 4. The ultrasonic element 1 is installed above the washing tub 5. In FIG. 1, one ultrasonic element 1 is used, and this element is used for both transmission and reception. At the time of output, the ultrasonic oscillation drive circuit 6 in the control device 4 oscillates, and the input thereof is amplified by the amplifier 7. The amplifier 7 is connected to a comparator 8, an ultrasonic element abnormality detection means 9, and a high water level setting means 10 for controlling the water supply valve 2.

In the cloth amount detection device configured as above,
The operation will be explained below. FIG. 2 shows a timing diagram during oscillation and reception after the output of the amplifier 7 when the ultrasonic element 1 is normal. As can be seen from this figure, T ₁ is the oscillation time, and T ₂ is the reverberation time during which oscillation continues due to the mechanical structure of the ultrasonic element 1 even after the oscillation signal of the ultrasonic oscillation drive circuit is stopped.
This oscillation time T ₁ and reverberation time T ₂ become the oscillation signal A ₁ . P ₁ indicates the received signal. Now, if the comparison voltage of the comparator 8 is Vref in Figure 2, the transmitted signal A ₁ crosses Vref at time t ₁ and the received signal P ₁ crosses Vref at time t ₂ as shown in Figure 2. . If the outgoing signal _A1 is normal, it always crosses at the same time _t1 . Received signal P ₁
The cloth surface changes depending on the water surface situation, and t ₂ moves.

However, FIG. 3 shows an example where the ultrasonic element 1 is abnormal, such as when water droplets are attached to the element or a wire is broken. As can be seen from this figure, when there is an abnormality, the reverberation time T ₃ determined by the ultrasonic element 1 becomes shorter (this is because, for example, water droplets attach to the ultrasonic element and increase the damping effect of the ultrasonic element). Therefore, the cross point t ₃ of Vref is also shorter than t ₁ under normal conditions (t ₃ <t ₁ ). Furthermore, the received signal _P2 also does not cross Vref because the sensitivity of the element is reduced. In other words,
It is possible to detect an abnormality in the ultrasonic element by looking at the change in the reverberation time _T3 , and this is detected by the ultrasonic element abnormality detection means 9 shown in FIG. Once an abnormality is detected, the output is input to the high water level setting means 10, which opens the water supply valve 2 and supplies water to the washing machine up to the maximum water level set. When the water level reaches the highest level, the water level sensor 3 detects the water level, sends a signal to the control device 4, and the control device 4 stops the water supply valve 2. Therefore, washing is carried out at the highest water level and there is no damage to the fabric.

Effects of the Invention According to the present invention as in the above embodiments, even if the ultrasonic element malfunctions and the amount of cloth cannot be detected and the water level is not automatically determined, the water level is automatically set to the highest level. , there is no problem in practical use of the washing machine. In this way, the water level is automatically determined during normal times, and reaches the highest water level during abnormal times, making it possible to wash clothes without damaging them. Note that if the ultrasonic element is configured to notify the user of the abnormal state with sound or light when an abnormality occurs, the washing machine can be used more efficiently.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the apparatus of the present invention, FIG. 2 is a timing diagram when the ultrasonic transmission and reception signals of the apparatus are normal, and FIG. 3 is a timing diagram when the same is abnormal. 1... Ultrasonic element, 2... Water supply valve, 3... Water level sensor, 4... Control device, 5... Washing tub, 9...
Ultrasonic element abnormality detection means, 10... high water level setting means.

Claims (1)

[Claims] 1. An ultrasonic element installed above the washing tub to detect the amount of cloth, a water level sensor to detect the water level in the washing tub, a water supply valve that supplies water to the washing tub, the ultrasonic element, the water level sensor, and a control device that controls a water supply valve, and the control device includes ultrasonic element abnormality detection means for detecting that the ultrasonic element is in an abnormal state, and sets the water level to the highest water level when the abnormality is detected. A cloth amount detection device for a washing machine, comprising a high water level setting means, the high water level setting means controlling a water supply valve based on an output from the water level sensor.