CN101487730B - Method and device for detecting water level of washing machine - Google Patents

Abstract

The invention relates to a water level detection method and device for washing machine, which uses a capacitance sensor composed of PCB substrate and metal sheet to detect the water level in the water cylinder of washing machine, the metal sheet is closely attached to the outer wall of the communicating part communicated with the water cylinder of washing machine, or the metal sheet is directly attached to the outer wall of the water cylinder, it can sense the change of water level to change its capacitance value, and a control unit is used to detect and process the capacitance value of the capacitance sensor, so as to calculate the water level and control the water level. The invention adopts the capacitance sensor, which can sense the micro strain of the communicating part or the outer wall of the water containing barrel caused by the water level change, the water level detection is more accurate, the stability is high, the structure is simple, and the sensor is mainly composed of a PCB and a metal sheet, and the cost is lower.

Description

Method and device for detecting water level of washing machine

technical field

The invention relates to a washing machine, in particular to a washing machine water level detection method and a device thereof, which can more accurately detect the water level in the washing machine's water tank.

Background technique

The washing machine includes a body, a door, a water tub, a clothes tub, a drive and a control system, the door is located on the front or top of the body for opening and closing, the water tub is fixed inside the body by a suspension mechanism, and is cylindrical in shape that opens toward the door. The clothes tub is installed in the water tub, the drive system wipes and drives the motor to rotate, and the control system controls the entire washing process of the washing machine.

At present, the washing machine is fully automatic control. The user only needs to put the laundry into the clothes tub, select the washing method, and press the start switch, and the washing machine will automatically detect the amount of laundry put into the clothes tub The amount of laundry, and then automatically add water that matches the amount of laundry, and then start the entire washing process.

In order to make the water intake reach the water level that matches the amount of laundry, in the existing washing machine, the pressure sensor is used to detect the water level of the water put into the water tank, such as the Chinese invention patent with the patent application number 200410059262.1 "Having a water level detection unit Drum type washing machine", discloses a water level detection unit of a drum type washing machine, which includes a water level sensing hose, which is connected to the suction pipe of the washing machine drain pump so as to communicate with the water tank, and also includes a water level detector, Installed on the upper end of the water level sensing hose, it is used to detect the air pressure in the water level sensing hose and the water level contained in the water tank. The water level sensing hose includes a large diameter part and a small diameter part. A water level detector is installed at the upper end, the large diameter part is connected to the lower end of the small diameter part, and the large diameter part communicates with the lower part of the water storage cylinder through the suction pipe and the discharge pipe of the drain pump, so when water is supplied into the water storage cylinder, the large diameter The water level of the diameter part will also increase. When the water level of the large diameter part increases, the air in the water level sensing hose is compressed, the pressure in the water level sensing hose increases, and the water level detector detects the pressure change, thereby detecting The level of water contained in the tub.

This method of using a water level detector to detect the air pressure in the water level sensor hose to detect the water level in the water tank has low accuracy and is greatly affected by the environment. The vibration of the washing machine and the sundries in it will affect the water level detection. The detection accuracy of the sensor, especially for the detection of lower water levels, is even more inaccurate, and the cost is also higher.

In addition, capacitive water level detection devices are also used in the prior art, such as the Chinese patent No. ZL01231098.0, which discloses a "capacitive water level detection device", which uses a metal conductor wrapped with an insulating layer as the water level Sensor, the water level sensor is vertically installed in the water tank that needs to detect the water level, most of it can be located in the water tank, the ground wire is connected to the water tank, a capacitance that can change with the rise and fall of the water level is formed between the water level sensor and the water, through the electronic circuit Convert the capacitance that changes with the water level into a continuously changing electrical signal, and input it to other control circuits, so as to realize the water level detection in the water tank. This water level sensor needs to be put into the water in the water tank to be detected, because a clothes tube will be placed in the water tank of the washing machine, and laundry will be placed in the clothes tube, so this water level detection device is not suitable for washing machines.

At present, touch buttons have been gradually used in home appliances. Touch buttons use capacitive touch panels. At the moment, a capacitance is generated on the surface of the board, and the touchpad is connected with a highly integrated chip, which can continuously track the "trajectory" of the user's finger capacitance, and accurately determine the position of the finger through a series of internal processing. This capacitive touch panel technology has been used in mobile phones and notebook computers for many years. It can sense only a light touch, and has stable performance and long service life in mechanical tests.

Contents of the invention

The main purpose of the present invention is to solve the above problems and provide a brand-new water level detection method of a washing machine, which can detect the water level more accurately, has high stability and low cost.

Another object of the present invention is to provide a detection device capable of realizing the above washing machine water level detection method, which has a simple structure and low cost.

In order to achieve the purpose of the above invention, the present invention provides a method for detecting the water level of a washing machine, which uses a capacitive sensor composed of a PCB substrate and a metal sheet to detect the water level in the water tank of the washing machine, and the metal sheet is fixed on the PCB substrate In the above, the PCB substrate and the metal sheet form a loop with the control unit through the connection, and the method includes the following steps:

Clinging the metal sheet to the outer wall of the water tank of the washing machine or the communicating part connected with the water tank;

When the water level in the water storage cylinder or the connecting portion changes, the metal sheet senses the change in water level, and accordingly changes the capacitance value of the capacitive sensor;

The above-mentioned capacitance value is detected by the control unit, and the water level is calculated to control the water level of the washing machine.

In order to achieve another object of the present invention, a device for realizing the water level detection method of a washing machine as described above includes: a connecting part communicated with the water tank of the washing machine; a capacitive sensor, the capacitive sensor includes a PCB substrate, wherein a A metal sheet, the metal sheet is closely attached to the outer wall of the connecting part, and is used to detect the change of the water level of the connecting part; a control unit is used to detect and process the capacitance value of the capacitive sensor, so as to calculate The height of the water level in the described water storage cylinder is displayed, thereby controlling the water level.

The communicating part is connected at or below the lowest water level of the water tub of the washing machine, for example, the communicating part can be connected upstream of the drain valve in the washing machine drain pipeline.

Another device of the present invention for realizing the water level detection method of a washing machine as described above includes: a capacitive sensor, the capacitive sensor includes a PCB substrate, and a metal sheet is fixed therein, and the metal sheet is closely attached to the water tub of the washing machine On the outer wall of the water storage tank, it is used to detect the water level change of the water storage tank; a control unit is used to detect and process the capacitance value of the capacitive sensor, so as to calculate the water level in the water storage tank, so as to control the water level.

The capacitive sensor is connected and fixed to the communication part or the outer wall of the water storage cylinder by clamping and/or adhesive bonding.

The control unit of the present invention includes a signal processing unit for converting the detected capacitance value into a voltage value, an amplifier, a shaping circuit, and a computer controller.

To sum up, the method and device for detecting the water level of the washing machine, because of the use of a capacitive sensor, can sense the slight strain on the outer wall of the water tank or the connecting part due to changes in the water level, and the detection of the water level is more accurate and stable. , the structure is simple, and the sensor is mainly composed of PCB substrate and metal sheet, and the cost is relatively low.

In addition, if the present invention is used on a washing machine with a touch button, it can use the redundant chip port of the original touch button chip of the washing machine to simultaneously process the detection of the water level change, further reducing the cost.

Description of drawings

Fig. 1 is a schematic structural view of a washing machine according to an embodiment of the present invention;

Fig. 2 is a schematic structural view of a washing machine according to another embodiment of the present invention;

Fig. 3 is a schematic diagram of a control unit of the present invention;

Fig. 4 is a schematic structural diagram of the capacitive sensor of the present invention.

As shown in Figures 1 to 4, a capacitive sensor 1, a water tank 2, a connecting part 3, a control unit 4, a drainage pipeline 5, a PCB substrate 6, a metal sheet 7, a washing machine body 8, a motor 9, and a clothes cylinder 10 , Drain valve 11, door 12, water supply pipeline 13, water inlet valve 14, signal processing unit 41, amplifier 42, shaping circuit 43, computer controller 44.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, the present invention is described in further detail: as shown in Figure 1, washing machine comprises body 8, door 12, water holding tube 2, clothes tube 10, driving and control system, and door 12 is positioned at the front of body 1, The water storage tube 2 is fixed in the body 8 by a suspension mechanism, and is a cylindrical shape opened towards the door 12. The clothes tube 10 is installed in the water storage tube 2, and the laundry tube 10 can be opened with the clothes to be washed or put into the clothes tube 10 by opening the door 12. Take it out, and the drive system drives the motor 9 to rotate. For the pulsator type washing machine, the motor 9 can drive the pulsator in the clothes drum 10 to rotate. For the drum type washing machine, the motor 9 can drive the clothes drum 10 to rotate, thereby washing the laundry drum 10 The control system controls the entire washing process of the washing machine. According to the water level detected by the control unit 4, the amount of clothes, and the washing program set by the user, the washing program is automatically controlled.

When doing laundry, first open the door 12, put in the clothes to be washed in the clothes tube 10, then put the washing powder into the washing powder inlet provided on the water supply pipeline 13, turn on the power switch, and start washing from the washing machine body 8 surface. The setting unit of the washing machine selects the operation mode according to the type of laundry, inputs the command to start the operation, and the washing machine control system starts to control the entire operation process.

The upper part of the water tank 2 of the washing machine is connected with a water supply pipeline 13, which is used to supply washing water required for washing into the water tank 2, and the lower part of the water tank 2 is connected with a drainage pipeline 5, and the drainage pipeline 5 is used as a When the washing process ends, the washing water in the water storage cylinder 2 is discharged. A drain valve 11 is provided on the drain pipeline 5 , and a water inlet valve 14 is provided on the water inlet pipeline 13 .

After the laundry program is started, the amount of clothes put into the clothes tub 10 must be detected first, then the water inlet valve 14 is opened, and washing water mixed with washing powder is supplied into the water tub 2 through the water supply pipeline 13, and the water inlet continues continuously. until the water reaches the level that matches the detected amount of laundry.

In one embodiment of the present invention, as shown in FIG. 1 , in order to accurately detect the water level in the water tank 2 of the washing machine, especially to detect the lower water level in the water tank 2 more accurately, the water outlet at the bottom of the water tank 2 and the drain The drainage pipeline 5 between the valves 11 is connected with a connecting part 3, and the change of the water level in the water storage cylinder 2 will cause the corresponding change of the water level in the connecting part 3, so it is only necessary to detect the water level in the connecting part 3. Correspondingly, the water level in the water tub 2 of the washing machine is determined.

Wherein the connecting part 3 may not be arranged on the drainage pipeline 5, but directly connected to the wall of the water storage cylinder 2 at the lowest water level.

The present invention sets a capacitive sensor 1, which includes a PCB substrate 6, on which a metal sheet 7 is fixed. Generally, the metal sheet 7 is made of copper sheet, which can be sensed as long as it is lightly touched. The performance is stable and reliable, and it is suitable for mechanical testing. It has a long service life. In addition, the sensor is mainly composed of a PCB substrate 6 and a metal sheet 7, with few components and low cost.

The metal sheet 7 is closely attached to the outer wall of the connecting part 3, and it can sense the slight strain caused by the increase or decrease of water on the outer wall of the connecting part 3, so that the distance between the metal sheet 7 and the PCB substrate 6 also changes with the If there is a slight change, the capacitance value will also change due to the change of the distance. The circuit is formed with the control unit 4 through the connection line located under the PCB substrate 6 and the metal sheet 7, and the capacitance value is transmitted to the control unit 4. The sensitivity of this sensor is very high, and it can sense small water level changes inside the connecting part 3, making the water level detection more accurate.

In another embodiment of the present invention, as shown in FIG. 2 , the capacitive sensor 1 can be directly pasted on the outer wall of the water storage cylinder 2 , and the detection method is as described above. In order to cooperate with various shapes of the water storage cylinder 2, the PCB substrate 6 can be made into a flexible circuit board, so that the metal sheet 7 can be completely attached to the outer wall of the water storage cylinder 2 to ensure the accuracy of detection.

Through the connection on the metal sheet 7 and the PCB substrate 6, the above generated capacitance value is transmitted to the control unit 4, and the control unit 4 detects the change of the above capacitance value, and calculates the water level correspondingly, thereby controlling the water level of the washing machine.

As shown in FIG. 2 , the control unit 4 is provided with a signal processing unit 41 , an amplifier 42 , a shaping circuit 43 and a computer controller 44 . The signal processing unit 41 is used to convert the detected capacitance value into a corresponding voltage value, and transmit the signal to the computer controller 44 through the amplifier 42 and the shaping circuit 43, and the computer controller 44 calculates the corresponding water level to further control the water level .

When the water level in the water tank 2 of the washing machine does not reach the set water level, the water inlet valve 14 is always opened. Water supply in the water cylinder 2. At this time, the water added to the water storage tube 2 will be absorbed by the clothes in the clothes tube 10, and the water level in the water storage tube 2 will drop. Therefore, the same method as above is required to replenish the water intake until the specified level is fully reached. water level.

After the water level in the water storage cylinder 2 reaches the specified water level, the washing machine can start the washing process. After the washing operation process is completed, the drain valve 11 below the water storage cylinder 2 will be opened to discharge the washing water in the water storage cylinder 2, and then Perform dehydration.

After the dehydration operation has been carried out for a specified time, the drain valve 11 is closed again, the water inlet valve 14 is opened, new water is added in the water holding cylinder 2, and the rinsing operation is started.

After carrying out the rinsing operation for a specified time, the dehydration operation is carried out again, and the above-mentioned process is repeated until all the washing operation processes are completed, and finally the power switch is turned off to end the operation.

The capacitive sensor 1 can be connected and fixed with the connecting part 3 or the outer wall of the water storage cylinder 2 by clamping. For example, a plurality of buckles (not shown in the figure) can be set on the communication part 3 or the outer wall of the water storage cylinder 2, and the capacitance The capacitive sensor 1 is stuck in the buckle, so that the capacitive sensor 1 is closely attached to the connecting part 3 or the outer wall of the water storage cylinder 2 .

In addition, the capacitive sensor 1 can also be coated with glue on the edge of the PCB substrate 6, and fixed on the connecting part 3 or the outer wall of the water tank 2 by glue sticking. Of course, the above two fixing methods can also be used at the same time.

The present invention can be applicable not only to drum washing machines, but also to pulsator washing machines. If the capacitive sensor 1 is directly attached to the outer wall of the water tank 2, multiple capacitive sensors 1 can also be arranged in parallel, so that the detection will be more accurate. , if one of them is damaged, the others can continue to be used without affecting the normal use of the washing machine.

Whether the capacitive sensor 1 is pasted on the connecting part 3 or on the outer wall of the water tub 2, the lowest point of the metal sheet 7 on it will be at or below the minimum water level required by the washing machine.

As mentioned above, a similar technical solution can be derived in combination with the solutions presented in the drawings and the embodiments. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention are still within the scope of the technical solutions of the present invention.

Claims (6)

1. washing machine level testing methods; It is characterized in that: its utilizes the capacitance type sensor of being made up of PCB substrate (6) and sheet metal (7) (1) to detect washing machine tin (2) the interior water level that is filled with water; Said sheet metal (7) is fixed on the said PCB substrate (6); Said PCB substrate (6) and sheet metal (7) are formed the loop through line and control module (4), and this method comprises the steps:

Said sheet metal (7) is close on the outer wall of the connected component (3) that washing machine is filled with water tin (2) or be connected with the tube (2) that is filled with water;

When the SEA LEVEL VARIATION in said be filled with water tube (2) or the said connected component (3), said sheet metal (7) is responded to the variation of water level, correspondingly changes the capacitance of said capacitance type sensor (1);

Detect above-mentioned capacitance through said control module (4), calculate the height of water level, thus the water level of control washing machine.

2. device of realizing washing machine level testing methods as claimed in claim 1, it is characterized in that: comprise a capacitance type sensor (1), said capacitance type sensor (1) comprises a PCB substrate (6), is fixed with sheet metal (7) on it; Also comprise a control module (4), be used for detecting and handling the capacitance of said capacitance type sensor (1), calculate the height of said tube (2) the interior water level that is filled with water with this, thus control water level;

Said sheet metal (7) is close to said washing machine and is filled with water on the outer wall of tube (2), is used to detect the SEA LEVEL VARIATION of the said tube (2) that is filled with water;

Or said sheet metal (7) is close to said washing machine and is filled with water on the outer wall of the connected component (3) that is communicated with of tube (2), is used to detect the SEA LEVEL VARIATION of said connected component (3).

3. washing machine condensate tank of dehumidifier according to claim 2 is characterized in that: said capacitance type sensor (1) is connected fixing through the mode of clamping and/or the mode of glue with the outer wall of the said connected component (3) or the tube (2) that is filled with water.

4. washing machine condensate tank of dehumidifier according to claim 2; It is characterized in that: said control module (4) comprises that one is used for the capacitance that detects is converted into voltage value signal processing unit (41); An amplifier (42), a shaping circuit (43), and computer controller (44).

5. washing machine condensate tank of dehumidifier according to claim 2 is characterized in that: said connected component (3) be connected washing machine be filled with water the tube (2) lowest water level or following place.

6. washing machine condensate tank of dehumidifier according to claim 5 is characterized in that: said connected component (3) is connected the upstream end of draining valve (11) in the washing machine drainage pipeline (5).

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