JPH0323186Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a water level detection device that can continuously detect changes in the water level in a water tank in a washing machine or the like.

(Prior art and its problems) Generally, in the case of a washing machine, etc., as shown in FIG. However, the water level in the water tank 1 is detected by receiving the pressure (air pressure) change in the air trap 2 via the pipe 3 due to the change in the water level in the water tank 1.

By the way, as a water level detection device that continuously detects changes in the water level in the water tank 1 with such a configuration, for example, as shown in FIG. has been proposed, and its structure is the third
This will be explained according to the diagram.

In FIG. 3, 5 is a case, 6 is a diaphragm, 7 is a case cover that sandwiches the outer circumference of the diaphragm 6 with the case 5, and 8 is a diaphragm 6.
9 is a magnetic material attached to the movable member 8; 10 is a coil attached to the case cover 7, which is a fixed member; 11 is a spring that urges the movable member 8 in one direction; 12 is a spring retainer; 13 is an adjustment screw, and 14 is an inlet provided in the case 5. The structure is such that the inlet 14 is connected to the air trap 2 via the pipe 3. Therefore, according to this structure, the pressure inside the case 5 changes as the pressure inside the air trap 2 changes, that is, the water level inside the water tank 1 changes, and the diaphragm 6 and the movable member 8 respond to the above pressure and the biasing force of the spring 11. The magnetic material 9 moves in and out of the coil 10 due to the force relationship, and the water level can be continuously detected by changing the inductance of the coil 10 due to the movement of the magnetic material 9 in and out.

However, in this conventional structure, the spring 11
is inside the coil 10 and expands and contracts, so the inductance of the coil 10 is equal to the spring 1
1 is also displaced due to the expansion and contraction of the magnetic material 9, it is not possible to accurately detect the change in inductance due only to the amount of displacement of the magnetic material 9, and the water level detection accuracy is low.

Also, due to variations in the dimensions of each component, coil 1
Although it is desirable to initially adjust the inductance of 0, in the conventional structure, the magnetic material 9 and the coil 10
In order to freely adjust the positional relationship between the case cover 7 and the coil 10, it is necessary to make the case cover 7 and the case part of the coil 10 separate parts so that the case parts can be moved, which results in a complicated structure. This also increases costs.

(Purpose of the invention) The present invention has been made in view of the above points, and aims to eliminate the drawbacks of the conventional method by arranging the magnetic material and the coil so as to avoid the area where the spring is located.

(Example) An example of the present invention shown in FIG. 1 will be described in detail below. In FIG. 1, parts common to those in FIG. 3 are given the same reference numerals.

In FIG. 1, the magnetic material 15 is attached to the outer circumference of the movable member 8, avoiding the center of the movable member 8, that is, the area where the spring 11 is located, and the magnetic material 15 is attached to the case cover (fixed member) 7. A screw hole 16 is provided at the opposing position, and the bobbin 18 of the coil 17 is screwed into the screw hole 16, so that the distance between the coil 17 and the magnetic material 15 can be arbitrarily adjusted by rotating the coil 17 from the outside. . Therefore, if it is necessary to adjust the initial value of the inductance of the coil 17, it can be easily done, and there is no need to divide the case cover 7 as in the conventional case, which simplifies the structure. can do.
Further, the magnetic material 15 and the coil 17 are connected to the spring 11.
Since the inductance of the coil 17 due to the expansion and contraction of the spring 11 is almost negligible and can be ignored, the amount of change in the inductance of the coil 17 is due to the displacement of the magnetic material 15 and the coil due to the displacement of the movable member 8. It is proportional to the amount of distance change between 10 and 10. This allows the water level in the aquarium 1 to be detected more accurately, and the detection accuracy is extremely high.

In addition, 19 in FIG. 1 is a balance weight provided on the movable member 8 at a position symmetrical to the magnetic material 15. This balance weight 19 may be integrated with or separate from the movable member 8, and the center of gravity of the movable member 8 is the center of the balance weight. This is to allow the movable member 8 to move smoothly without tilting by positioning it on a line.

(Effect of the invention) As described above, the present invention provides a diaphragm 6 that is displaced in response to a pressure change due to a change in the water level in the water tank in the cases 5 and 7, and is biased in the opposite direction of the displacement of the diaphragm 6 due to this pressure. spring 1
1 is provided at the center of the diaphragm 6 via the movable member 8, a magnetic material 15 is provided at the outer periphery of the diaphragm 6 on the displacement direction side, and a bobbin 18 is provided in the case 7 corresponding to the position of the magnetic material 15. is threaded through the case 7 to expose the rear end of the bobbin 18 to the outside of the case 7, and the diaphragm 6 is attached to the bobbin 18 inside the case 7.
This water level detection device is provided with a coil that approaches the magnetic material 15 according to the displacement of the magnetic material 15.

Therefore, depending on the water level change, the diaphragm 6
is displaced, the coil 17 and the magnetic material 15
Since the inductance of the coil changes as the distance from the coil changes, changes in the water level can be continuously detected using this change in inductance.

In this case, the magnetic material 15 and the coil 17 are located on the outer periphery of the diaphragm 6 and are separated from the spring 11 that biases the diaphragm 6, so the presence of the spring 11 influences the change in inductance of the coil 17. The water level can be detected accurately.

Also, a bobbin 18 supporting the coil 17 is provided.
penetrates through the case 7 and is screwed into the case 7 with its rear end exposed outside the case 7, so by rotating this bobbin 18 from outside the case 7, the position of the coil 17 relative to the magnetic material 15 can be adjusted. This makes it easy to initialize and adjust the water level detection device.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a water level detection device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the relationship between a water tank and the water level detection device, and FIG. 3 is a sectional view showing a conventional water level detection device. . DESCRIPTION OF SYMBOLS 1... Water tank, 2... Air trap, 4... Water level detection device, 6... Diaphragm, 7... Case cover (fixed member), 8... Movable member, 11... Spring, 15... Magnetic material, 17 ……coil.

Claims (1)

[Claims for Utility Model Registration] A diaphragm 6 is provided in the cases 5 and 7 to be displaced in response to pressure changes due to changes in the water level in the water tank, and a spring is provided that biases the diaphragm 6 in a direction opposite to the displacement of the diaphragm 6 due to this pressure. 11 as the movable member 8
A magnetic material 15 is provided at the outer periphery of the diaphragm 6 in the displacement direction, and a bobbin 18 is screwed into the case 7 corresponding to the position of the magnetic material 15 to form a case. 7 to expose the rear end of the bobbin 18 to the outside of the case 7, and a diaphragm 6 to the bobbin 18 inside the case 7
A water level detection device characterized in that a coil is provided which approaches the magnetic material 15 according to the displacement of the magnetic material 15.