JPH0449552Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] <Industrial application field> The present invention is used to detect and notify the remaining amount of liquid in various liquid tanks such as vehicle window wash liquid tanks. Regarding the float type liquid level sensor,
In particular, the present invention relates to a housing structure of a float type liquid level sensor for housing a board equipped with a reed switch operated by a magnet mounted on a float.

<Prior art> In general, liquid level sensors are
No. 61-46428, etc.,
A float fitted to a cylindrical float guide shaft integrally formed in the housing is raised and lowered in accordance with the liquid level in the tank, and a magnet attached to the float operates a reed switch inside the float guide shaft. , to detect the liquid level. The reed switch can be attached to a predetermined position on a printed circuit board, and the board can be inserted and fixed inside the float guide shaft to be placed at an appropriate position.

However, the hole drilled in the axial direction inside the float guide shaft to accommodate the board is long and narrow, and the entrance opened in the housing is narrow, so when inserting the board, the reed switch may touch the area around the entrance or the inner wall of the hole. There is an inconvenience of collision and damage. Additionally, when fixing a board that has been filled with adhesive or the like in the hole, if an external force is applied to the lead wires connected to the board, the position of the board will shift and the reed switch will not be fixed in the correct position. , there is a possibility that the liquid level sensor may not be able to perform its desired function. Furthermore, if only the tip of a long and thin board is fixed with adhesive, there is a drawback that the board will bend due to vibrations or impacts during use, and the reed switch will hit the inner wall of the hole and be damaged. .

<Problems to be solved by the invention> Therefore, the purpose of the invention is to store the board without damaging the reed switch, improve workability so that it can be positioned at the desired proper position, and to remove the lead switch during use. It is an object of the present invention to provide a housing structure for a float type liquid level sensor that can hold a substrate so that a switch is not damaged.

[Structure of the invention] <Means for solving the problem> According to the present invention, the above object is to provide a float guide shaft on which a float equipped with a magnet is fitted so as to be able to rise and fall, and an axis line on the float guide shaft. A float type liquid comprising: a hole for accommodating a board equipped with a reed switch operated by the magnet, which is drilled in the direction; and a head part integrally molded with the float guide shaft and defining the entrance of the hole. The housing structure of the surface sensor includes a pair of opposing first walls extending along the axial direction and into which the substrate is inserted; a pair of opposing second
A box-shaped peripheral wall is formed around the periphery of the entrance to define a cross-shaped opening corresponding to the cross-sectional shape of the hole, and at least the substrate This is achieved by providing a housing structure for a float type liquid level sensor, in which one of the pair of opposing wall portions of the peripheral wall portion into which the liquid level sensor is fitted is formed higher than the other portion.

<Function> By doing this, the board on which the reed switch is attached is inserted into the hole by being guided by the peripheral wall defining the entrance of the hole, and the board is fitted between the first wall of the hole. The reed switch can be housed without colliding with the vicinity of the entrance or the inner wall of the hole, and the board can be appropriately positioned.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 schematically shows a float type liquid level sensor to which the present invention is applied. This liquid level sensor 1
It is usually used by hanging downward from the top wall of the tank. Housing 2 integrally molded with synthetic resin
The float guide shaft 3 includes an elongated cylindrical float guide shaft 3 and a head portion 4 provided above the float guide shaft 3. A substantially cylindrical float 5 is loosely fitted into the float guide shaft 3 so as to be movable in the axial direction. An annular magnet 6 is fixed to the inner peripheral portion of the float 5. The housing 2 is provided with a hole 7 that opens at the upper end of the head portion 4 and extends in the axial direction over the entire length of the float guide shaft 4. A printed circuit board 8 equipped with a reed switch operated by the magnet 6 is housed in the hole 7.

Further, a cylindrical float cover 9 is attached to the outside of the housing 2 so as to surround the float 5 and the float guide shaft 3. A protrusion 10 is formed at the lower end of the float guide shaft 3 to hold a stopper that engages with the bottom of the float cover 9 and limits the lower limit position of the float 5 . Also,
A float 5 is located near the upper end of the float guide shaft 3.
A pair of stoppers 11 are provided in a protruding manner to limit the upper limit position.

As shown in Figures 2 to 4, the hole 7 has a cross-shaped cross section.
In FIG. 4, the space extending in the left-right direction of the cross is
A space defined by a pair of first walls 12a, 12b facing each other with a narrow gap corresponding to the thickness of the substrate 8 and extending in the vertical direction of a cross is a first
A pair of second walls 13 are perpendicular to the walls 12a and 12b and face each other with a relatively wide gap therebetween so as to accommodate the reed switch mounted on the substrate 8.
The wall portions 12a, 12b, 13a, and 13b are adjacent to each other.
Since the four ribs 14a to 14d protruding toward the center of the hole 7 are formed over the entire length of the hole 7 by the portion b, the bending rigidity of the float guide shaft 3 is improved.

The head portion 4 has a disc-shaped flange 15,
Further, an inlet peripheral wall portion 17 for defining an inlet 16 of the hole 7 opening upward is formed on the upper surface thereof. The inlet 16 has a cross-shaped opening corresponding to the cross-sectional shape of the hole 7. The entrance 16 is formed by a pair of first guide walls 18a, 18b, which have a cross-shaped space extending in the left-right direction in FIG. and first side walls 19a, 19b connecting them. The cross-shaped space of the entrance 16 extending in the vertical direction has a pair of second guide walls 20a, 20b facing each other with the same wide gap as the second walls 13a, 13b of the hole 7, and a second guide wall 20a, 20b that connects them. side wall 2
1a and 21b.

one first guide wall 18a and a first side wall 19a,
19b extends higher and upward than the other portions of the inlet peripheral wall 17. 1st guide wall 1
Through holes 22a and 22b are bored at predetermined positions in the upper part of 8a, through which lead wires connected to the substrate 8 pass. Furthermore, the first guide wall 1 is arranged so that the substrate 8 can be easily and smoothly inserted into the hole 7.
The inner upper edges of the first side walls 8a, 18b and the first side walls 19a, 19b are chamfered. Further, a step portion 23 for supporting the substrate 8 is formed in the entrance 16 between the first guide walls 18a and 18b.

5 to 7, the board 8 is attached to the housing 2.
It is shown in the stored state. The board 8 consists of a narrow sensor section 26 to which two reed switches 24 and 25 are attached at upper and lower positions, and a wide base section 27 to which lead wires are connected. The base 27 has four through holes 28a, 2 for connecting lead wires.
8b, 29a, 29b are bored.

The board 8 has reed switches 24 and 25 at the entrance 1.
The sensor section 2
Both side edges of the hole 7 are guided to the inner surface of the first guide wall 18a and fitted between the first wall portions 12a and 12b of the hole 7. The base 27 has one side connected to the first guide wall 18a.
The base portion 27 is guided by the inner surface and inserted into the entrance 16 until the lower end of the base portion 27 comes into contact with the stepped portion 23. and,
An adhesive 30 is filled in the hole 7 to fix the tip of the substrate 8 to the bottom of the hole 7. In this way, by fitting the board 8 between the first walls 12a and 12b and between the first guide walls 18a and 18b as shown in FIG. 6, the board 8 is positioned laterally, and As shown in FIG.
The substrate 8 is positioned in the axial direction by bringing it into contact with the substrate 8 .

As shown in FIG. 7, lead wires 31 are connected to the holes 28a, 28b on the lower side of the base 27 through the through holes 22a, 22b from the rear side of the first guide wall 18a. Therefore, even if force is applied from the outside through the lead wire 31 when filling the adhesive 30, the position of the substrate 8 will not shift because the base 27 is supported by the first guide wall 18a. . Further, lead wires are directly connected to the holes 29a and 29b on the upper side of the base 27, as in the conventional case. These lead wires are electrically connected to, for example, a control unit, and when the reed switches 24 and 25 are activated by raising and lowering the float 5, a signal is sent to warn of the remaining amount in the tank. There is.

In the above embodiment, the housing of the liquid level sensor is installed downward from the top wall of the tank, but the present invention can be similarly applied to the housing of the liquid level sensor that is installed upward from the bottom wall of the tank. It goes without saying that it can be done.

[Effects of the invention] As described above, according to the invention, a hole having a cruciform cross-sectional shape is bored inside the float guide shaft, and a cruciform box-shaped peripheral wall defining the entrance of the hole. By forming a reed switch in the head part, the board can be inserted into the hole while being guided by the peripheral wall, so the reed switch is not damaged when storing the board, improving work efficiency, and making it easier to use. Damage to the reed switch due to bending of the board inside can be prevented. Furthermore, by connecting the lead wire to the substrate by penetrating the peripheral wall, it is possible to prevent the substrate from shifting during filling with adhesive, thereby ensuring proper functioning of the liquid level sensor.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a float type two-stage liquid level sensor to which the present invention is applied. FIG. 2 is a top view of the housing according to the present invention. Figure 3 is. FIG. 3 is a vertical cross-sectional view taken along the - line in FIG. 2; FIG. 4 is a cross-sectional view taken along the - line in FIG. 3. FIG. 5 is a longitudinal cross-sectional view showing a state in which the board is attached to the housing. FIG. 6 is a top view of FIG. 5. FIG. 7 is a partial vertical sectional view showing the connection state of the lead wires. 1...Liquid level sensor, 2...Housing, 3...
Float guide shaft, 4... Head portion, 5... Float, 6... Magnet, 7... Hole, 8... Board, 9... Float cover, 10... Projection, 11
...Stopper, 12a, 12b...First wall part, 1
3a, 13b... second wall portion, 14a to 14d...
Rib, 15...flange, 16...inlet, 17...
...Entrance peripheral wall portion, 18a, 18b...First guide wall, 19a, 19b...First side wall, 20a, 20
b...Second guide wall, 21a, 21b...Second side wall, 22a, 22b...Through hole, 23...Step part,
24, 25... Reed switch, 26... Sensor section, 27... Base, 28a, 28b, 29a, 2
9b...Through hole, 30...Adhesive, 31...Lead wire.

Claims (1)

[Claims for Utility Model Registration] (1) A float guide shaft on which a float equipped with a magnet is fitted so as to be able to move up and down, and a reed switch operated by the magnet, which is bored in the float guide shaft in the axial direction. A housing structure for a float type liquid level sensor, comprising a hole for accommodating a mounted board, and a head part integrally molded with the float guide shaft to define an entrance of the hole, the hole having an axis line. a pair of opposing first wall portions extending along the direction and into which the substrate is fitted; and a pair of opposing first wall portions extending perpendicularly to the first wall portions into which the reed switch is fitted. a box-shaped peripheral wall is formed around the periphery of the inlet to define a cross-shaped opening corresponding to the cross-sectional shape of the hole; A housing structure for a float type liquid level sensor, wherein one of a pair of opposing wall portions of the peripheral wall portion into which a substrate is fitted is formed higher than the other portion. (2) A utility model according to claim 1, characterized in that a through hole is formed in the one wall portion of the peripheral wall portion, through which a lead wire connected to the substrate is inserted. Housing structure of float type liquid level sensor.