JPH0547238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a water amount detection device for a washing machine that can determine the optimum water level depending on the amount of laundry.

Conventional technology In conventional washing machines, in order to automatically control the amount of water supplied, an ultrasonic transmitter/receiver transmits ultrasonic waves, and the ultrasonic waves are reflected back to the target object, the laundry. The amount of laundry was detected based on the delay time, and the amount of water was determined and supplied according to the amount of laundry.

Problems to be Solved by the Invention However, with the conventional technology, if the amount of laundry to be detected is uneven, it is not possible to accurately detect the amount of laundry, and the amount of water corresponding to the detected amount of laundry may cause the laundry to fall to the surface of the water. There was a problem in that the laundry did not sink to the bottom and washing etc. could not be done at the optimal water level where the laundry sank below the water surface.

In view of the above problems, the present invention provides a water amount detection device for a washing machine that accurately detects the optimal water level at which laundry sinks below the water surface.

Means for Solving the Problems A washing machine with a water level detection device according to the present invention includes an ultrasonic transmitter and a receiver provided in a washing tub having a water level sensor, and a signal from a distance measuring device connected to the ultrasonic receiver. The control device controls the motor drive device and the water supply valve drive device.

Function With this configuration, the time taken to reflect the ultrasonic wave and receive the signal is measured, the distance to the detected object is obtained, and this is compared with the initially set water level.
When these match, the laundry is submerged below the water surface, and the water level can be set to the optimum level.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration diagram of a water amount detection device for a washing machine according to the present invention, where 1 is a washing tub, 2 is the laundry in the washing tub 1, 3 is a washing start switch, and 4 is for overall control. Control device,
5 is a water supply valve driving device connected to and controlled by the control device 4; 6 is a water supply valve that supplies water to the washing tub 1 connected to the water supply valve driving device 5; 7 is a water level sensor connected to the washing device 1; 8 is a A motor drive device connected to the output of the control device 4, a motor 9 connected to the motor drive device 8, and a pulsator 10 connected to the motor 9, located at the inner bottom of the washing tub 1. 11 and 12 indicate an ultrasonic transmitter and an ultrasonic receiver installed above the washing tub 1, and 13 indicates a distance measuring device connected to the ultrasonic transmitter 11 and receiver 12, whose input and output are as follows. It is connected to the control device 4. Further, the distance measuring device 13 includes an ultrasonic receiving section 13a, an ultrasonic transmitting section 13b, a time measuring section 13c, and a distance converting section 13d.

The operation of the water amount detection device configured as above will be described below. First, the laundry 2 is put into the washing tub 1. Next, press the washing start switch 3. Then, a signal is output from the control device 4, and the water supply valve drive device 5 operates to open the water supply valve 6, and the washing tub 1 is opened.
Water is supplied to the tank, and the amount of water accumulates to the initially set low water level. Next, the water level sensor 7 detects that the water level has reached a low level and sends a signal to the control device 4. Control device 4
operates the water supply valve driving device 5, closes the water supply valve 6, and stops the water supply. Next, the control device 4 sends a signal to the motor drive device 8 for a certain period of time, the motor 9 and the pulsator 10 rotate for a certain period of time, and the laundry is agitated. Therefore, the laundry and water become compatible, and when the amount of laundry is small, all of the laundry 2 sinks under the water surface, and when there is a large amount, the laundry does not sink under the water surface. Now, suppose that the amount of laundry is so small that it all sinks below the surface of the water. Then, with the motor 9 stopped and the water surface stable, the ultrasonic transmitter 11 installed above the washing tub 1 emits ultrasonic waves, the reflected waves are received by the ultrasonic receiver 12, and the time (T ), the distance measuring device 13 converts this into the distance (L) between the ultrasonic transmitter 11 and the water surface, and sends the signal to the control device 4.
At this time, as shown in FIG. 2, the difference T between the sending time and the receiving time and the distance have the following relationship.

L=C×T/2 (C: speed of sound) The control device 4 compares the initially set low water level with L, and if they match, all the laundry sinks under the water surface and the water level is lower than the washing level. judged to be the most suitable for the object,
Move on to the washing process. Next, when the amount of laundry is large, the washing machine 2 remains above the water surface even after stirring for a certain period of time. Therefore, the distance L measured by the distance measuring device 13 is different from the initially set distance of the low water level. Then, the control device 4 causes the water supply valve driving device 5 to open the water supply valve 6 to supply water. Then, the water level becomes the next lower water level than the low water level, at which point the water level sensor 7 operates and sends a signal to the control device 4 to close the water supply valve 6 and stop the water supply. Here, in the same operation as described above, the distance measurement device 13 measures the distance using ultrasonic waves, and if they match, it is determined that the amount of water is the optimum amount, and if not, the same operation is repeated thereafter to obtain the optimum amount of water. In this way, the state in which the laundry is completely submerged in water, that is, the optimal amount of water is automatically determined.

Although the pulsator 10 is driven and stirred for a certain period of time in order to obtain the optimum amount of water, if the laundry is submerged by water supply, stirring is not necessarily necessary. There are also cases where the laundry contains air and does not submerge in water, in which case stirring is effective. Furthermore, there are cases where the laundry is a thin cloth and floats on the surface of the water, but if a certain width is set in measuring the distance to the water surface, there will be no problem in actual use.

Effects of the Invention As is clear from the present invention, if the laundry is submerged under the water surface, the water level in the washing tub detected by the water level sensor matches the distance information of the distance measuring device, so this point is optimal. According to the present invention, it is possible to directly detect the state where the laundry is submerged under the water surface, and the optimum water level can be accurately determined.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a washing machine equipped with a water amount detection device showing an embodiment of the present invention, and FIG. 2 is a diagram showing the timing of ultrasonic distance measurement. 1... Washing tub, 2... Laundry, 4... Control device, 11... Ultrasonic transmitter, 12... Ultrasonic receiver, 13... Distance measuring device.

Claims (1)

[Claims] 1 A washing tub having a pulsator, a motor and a motor drive device for driving the pulsator, a water supply valve and a water supply valve drive device for supplying water to the washing tub, an ultrasonic transmitter and an ultrasonic receiver provided above the washing tub. , a distance measuring device that measures the distance between the ultrasonic transmitter and the ultrasonic receiver and a detected object in the washing tub, and a water level sensor that detects the water level of the washing tub;
Control that compares the distance information of the distance measuring device and the set water level, determines the point in time when the water level of the washing tub matches the distance information of the distance measuring device as the optimum water level, and controls the motor drive device and the water supply valve drive device. A water amount detection device for a washing machine having a device.