JP2595434B2 - Fire detector waterproof structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof structure for a fire detector, and more particularly to a waterproof structure for a lead wire outlet for connecting a printed circuit board horizontally fixed in the body of a heat detector to the outside. .

[0002]

2. Description of the Related Art In general, in a heat sensor, a lead wire outlet for connecting a printed circuit board in a main body to the outside must be provided with a waterproof structure so that water from a ceiling does not enter the main body. As a conventional waterproof structure, for example, as shown in Japanese Utility Model Laid-Open No. 4-28390, a lead wire is drawn out from a lid in a vertical direction. The lead wire outlet is formed larger than the thickness of the lead wire,
A sealing material for waterproofing is filled between the outlet and the lead wire.

However, in such a waterproof structure,
When the work of filling the sealing material for waterproofing between the outlet and the lead wire is incomplete, there is a problem that the waterproofness is deteriorated. Then, as another conventional waterproof structure, for example, one disclosed in Japanese Utility Model Publication No. 4-9667 is known. This structure will be described with reference to FIG.
Is connected to one end of a lead terminal 2 bent into an L shape. A printer board 5 on which various electronic components 4 for heat detection are mounted is fixed in the housing 3 so as to be horizontal, and an upper portion of the housing 3, that is, a ceiling side is sealed by a horizontal lid 6.

After the lid 6 is formed in advance, the other end of the lead terminal 2 faces downward so that it can be connected to the printer substrate 5 and the lead wire 1 is laid horizontally along the horizontal lid 6. It is formed to be integrated by insert molding so as to be drawn out in the direction. That is, when this lead wire 1 is connected to the ceiling side, the lead wire 1
And the side surface of the lead terminal 2a has a crank shape.

[0005]

However, in the conventional waterproof structure described above, the lead terminal 2 bent into an L shape is used.
Insertion molding is performed while positioning the lead wire 1 with respect to the lid 6 such that the tip of the lead wire coincides with the connection position on the printed circuit board 5. Therefore, there are problems that variations occur and the manufacturing process becomes complicated. Further, since the lead wire 1 is drawn out in the horizontal direction and bent upward, there is a problem that a load is applied to the lead wire 1.

Further, since the lid 6 accommodates the lead wire 1 in the horizontal direction, an extra volume is required for the lid 6 and the size is increased. In the sensor for setting an address, a DIP switch is provided on the printed circuit board 5 and the switching operation of the DIP switch is performed. However, since the lead wire 1 is drawn out in the horizontal direction, the switching operation is complicated. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a waterproof structure of a fire detector capable of improving the waterproofness of a lead wire outlet through a simple structure and a manufacturing process.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a fire detector for waterproofing a lead-out opening of a lead wire for connecting a printed circuit board horizontally fixed to a sensor body to the outside. In the waterproof structure, a tip of a lead wire and a connection terminal fixed to the tip are insert-molded into a mold resin member, and a cover that covers the printed circuit board so that the connection terminal and the printed circuit board can be connected to each other. The molding resin member is vertically insert-molded.

The present invention is further characterized in that a member for positioning the connection terminal with respect to the mold resin member is formed on the connection terminal. The present invention is also characterized in that the material of the mold resin member has fluidity during molding and shrinkage when returned to normal temperature.

[0010]

According to the present invention, the tip of the lead wire and the connection terminal fixed to the tip are insert-molded in the vertical direction with respect to the resin, and the resin is insert-molded in the vertical direction with respect to the lid covering the printed circuit board. Therefore, a completely waterproof structure can be formed between the connection terminal and the resin and between the lid and the resin. Further, since only two insert molding operations are performed, the waterproofness of the lead wire outlet can be improved with a simple structure and a simple manufacturing process.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a manufacturing process diagram showing one embodiment of a waterproof structure of a fire detector according to the present invention. In the sensor shown in FIG.
As an example, a single lead wire 11 and a double lead wire 12 are pulled out from the main body, and for example, the lead wire 11 is used as a common, one of the lead wires 12 is connected to a fire receiver (not shown), and the other is connected. Connected to other sensors.

In this embodiment, first, as shown in FIGS. 1 (a) and 1 (b), the core wires 11a of the respective lead wires 11, 12 are fixed by crimping in the insert fittings 14 for connection terminals. The insert fitting 14 is formed in a substantially cylindrical shape, and its tip 14a has a conical shape so that it can be inserted vertically in two wire-like terminals 17c provided substantially parallel to the printed circuit board 17 as described later. Is formed.

The insert fitting 14 also has a tip 14a.
A circular flange portion 14b serving as a stopper when is vertically inserted, and a flange portion 14c serving as a vertical positioning member when being insert-molded into a mold resin member 15 described later. At the end, an opening 14d into which the core wire 11a of the lead wires 11, 12 is inserted is formed. In addition, each end of the two-core lead wire 12 is commonly inserted into the opening 14d of one insert fitting 14, and the periphery thereof is fixed by crimping.

As shown in FIG. 1C, the molding resin member 15 is formed by inserting the insert metal fittings 14 and the distal ends of the lead wires 11 and 12 and molding the printed circuit board as shown in FIG. 1D. It is formed so as to be insert-molded in a circular lid 16 covering the cover 17. Specifically, as shown in FIG. 2, the mold resin member 15 has two insert fittings 14 and the tip portions of the two lead wires 11 and 12 inserted therein, and the tip 14 a of the fitting 14 and the flange portion 14.
b is formed in such a size and shape as to protrude, and a flange portion 15a for improving waterproofness and positioning with the lid 16 is formed therearound.

An opening 16a for inserting the mold resin member 15 is formed in the cover 16 in advance.
The flange portion 15a of the mold resin member 15 is positioned with respect to a, and insert molding is performed. As a material of the lid 16, polycarbonate is used as an example, and as a material of the mold resin member 15, polybutylene terephthalate (PBT), which has a good flowability with respect to polycarbonate, is used.

PBT has good fluidity at the time of molding and good shrinkage when returned to room temperature. Therefore, PBT flows around the lead wire without any gap at the time of molding and then has good shrinkage when returned to room temperature. The waterproofness is further improved. In particular, when a two-core lead wire is formed, PBT flows reliably between the lead wires, and the effect is improved.

Next, referring to FIG.
The contact structure of the first embodiment will be described.
a is formed, and a land 17b is formed around the through hole 17a on the substrate 17. Two wire-like terminals 17c are soldered to the land 17b, for example, so as to be parallel to each other at an interval smaller than the diameter of the insert fitting 14.

Therefore, when the lid 16 is positioned and closed in the circumferential direction, the insert fitting 14 is inserted into the through hole 17a and connected to the two wire terminals 17c, and as a result, is connected to the land 17b. . Next, FIG.
The structure of such a waterproof sensor will be described with reference to FIG. The main body 20 is formed so as to be covered by the outer cover 21, and the printed circuit board 17 is fixed to the main body 20. The thermal sensor 1 is located below the printed circuit board 17.
8 is fixed, and the thermal sensor 18 is configured to be exposed to the outside.

The lid 16 is fixed to the main body 20 by screws 22 via a waterproof O-ring 23, so that the inside of the lid 16 has a waterproof structure. Although not shown, a base is attached to the ceiling in advance, and the main body 20 is fixed to the base by fitting a metal fitting 24 attached to the lid 16 to a fitting on the base side.

Therefore, according to the above embodiment, the core wires 11a of the lead wires 11 and 12 are fixed by crimping in the insert fitting 14, the insert fitting 14 is insert-molded in the mold resin member 15, and the mold resin member 15 Is molded in the lid 16, it is possible to prevent the occurrence of variations and complicate the manufacturing process.

Further, since the wire is drawn out in the horizontal direction and cannot be bent upward as in the conventional example, the lead wire 11,
No load is applied to the lid 12, and no extra volume is required for the lid 16. In the case of a sensor having an address, a DIP switch is provided on the printed circuit board 17 and switching of the DIP switch is performed. However, since the lead wire 1 is drawn out in the vertical direction, this switching operation becomes complicated. Nor.

[0022]

As described above, the present invention relates to a waterproof structure for a fire detector for waterproofing a lead wire outlet for connecting a printed circuit board horizontally fixed to a sensor main body to the outside. The tip of the wire and the connection terminal fixed to the tip are insert-molded into a mold resin member, and the mold resin member is attached to a lid that covers the printed board so that the connection terminal and the printed board can be connected. Since insert molding is performed in the vertical direction, a completely waterproof structure can be formed between the connection terminal and the resin and between the lid and the resin. Further, since only two insert molding operations are performed, the waterproofness of the lead wire outlet can be improved with a simple structure and a simple manufacturing process.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram showing one embodiment of a waterproof structure of a fire detector according to the present invention.

FIG. 2 is a diagram showing the mold resin of FIG. 1 in detail.

FIG. 3 is a perspective view showing a contact structure of a printed circuit board.

FIG. 4 is a side sectional view showing the entire fire detector.

FIG. 5 is a side sectional view showing a conventional fire detector.

[Explanation of symbols]

 11, 12: Lead wire 11a: Core wire 14: Insert fitting 14a: Tip 14a, 14b: Flange portion 14d: Opening 15: Mold resin member 16: Lid 17: Printed circuit board 17a: Through hole 17b: Land 17c: Wire terminal 18 : Thermal sensor 20: Main body 21: Outer cover 22: Screw 23: O-ring 24: Mounting bracket

Claims (3)

(57) [Claims] 1. A waterproof structure for a fire detector for waterproofing a lead-out opening of a lead wire for connecting a printed circuit board horizontally fixed to a sensor body to the outside, wherein the tip of the lead wire and the tip thereof are fixed. The connection terminal is insert-molded with respect to a mold resin member, and the mold resin member is vertically insert-molded with respect to a lid covering the printed board so that the connection terminal and the printed board can be connected. Fire detector waterproof structure. 2. A waterproof structure for a fire detector according to claim 1, wherein a member for positioning said connection terminal with respect to said mold resin member is formed on said connection terminal. 3. The waterproof structure for a fire detector according to claim 1, wherein the material of the mold resin member has fluidity during molding and shrinkage when returned to room temperature.