JP2646796B2 - Gas sensor and manufacturing method thereof - Google Patents

Description

The present invention relates to a gas leak alarm for LP gas or city gas or a gas sensor used to detect a gas component such as alcohol or carbon monoxide, and its manufacture. About the method.

[Conventional technology]

FIGS. 8 and 9 show a conventional example of a gas sensor used in this type of gas leak alarm.

FIG. 8 shows an example in which a contact combustion type gas sensor is used as the gas detecting element a. As is well known, a gas sensitive body is formed by sintering an oxidation catalyst layer on a platinum wire coil as is well known. Explosion proof in which both ends of the platinum wire coil a1 of the gas sensor a are connected to two lead terminals insert-molded in the resin base b, and a stainless steel wire mesh is formed in a hat shape to form one or two sheets. A net d is fixed to the resin base b by a caulking fitting e so as to cover the gas sensor a.

FIG. 9 shows an example in which a so-called semiconductor gas sensor using a metal oxide semiconductor as a gas sensitive body is used as a gas sensor.
As is well known, this semiconductor type gas sensor is provided with a tin oxide-based semiconductor gas sensitive body coupled to a pair of electrodes on one surface of a sensor substrate, and connected to a power supply by a pair of electrodes on the other surface of the sensor substrate. There is provided an electric heater for heating the gas sensitive body to be used. By providing a pair of electrodes on both surfaces of the sensor substrate as described above, this gas sensor is provided with four lead terminals c penetrating the resin base b, and the four lead terminals c Are connected to each other by a conductor line f. This gas sensor a is also fixed to the resin base b by a caulking fitting e so that the explosion-proof net d covers the gas sensor a as in FIG.

[Problems to be solved by the invention]

The external shape of the above-described conventional gas sensor has a round shape as shown in FIGS. 8 and 9, and when this gas sensor is mounted on a printed circuit board, a useless space is generated between adjacent components. Therefore, it greatly hinders the demand for miniaturization. Further, in assembling this gas sensor, a lead terminal c is integrally attached to the resin base b, and then the gas sensor a is connected to the lead terminal c, and then a cap-shaped explosion-proof net d is put on the resin base b. Since the resin base b and the explosion-proof net e are formed in a round shape, alignment rectification and handling at the time of component supply are extremely difficult. It has the drawback that it is difficult to assemble and the cost is high due to the availability.

Accordingly, a first object of the present invention is to provide a gas sensor having a structure which can eliminate the above-mentioned drawbacks of the conventional device and can be reduced in size and space.

A second object of the present invention is to provide a method of manufacturing a gas sensor that can complete a gas sensor simply by putting a component material into an assembly line.

[Means for solving the problem]

In order to achieve the first object described above, the present invention employs a cross section U.
A square base, a lead terminal passing through the base of the base, a gas detection element connected by a lead terminal located between both legs of the base having a U-shaped cross section, and an opening in the base having a U-shaped cross section The gas sensor is characterized by comprising a U-shaped explosion-proof net covering the portion.

In order to achieve the second object described above, the present invention provides a support member having a bridge that bridges the entirety, a support piece having a gas detection element positioning recess connected to the support, and lead terminals located on both sides of the support piece. And forming a lead frame by punching out a single good conductor metal plate, placing the gas detection element in the gas detection element positioning recess of the support piece of the lead frame, placing the electrode of the gas detection element and the lead terminal. Are connected by a conductor wire, and the lead terminals of the lead frame are integrally formed and attached to a base having a U-shaped cross section, a support piece is cut from the lead frame, and an opening of the base having the U-shaped cross section is formed. An explosion-proof net formed in a U-shape to cover the base is put on the base, the fitting portion between the explosion-proof net and the base is heated, and the resin of the melted base penetrates into the stitches of the explosion-proof net and cools and solidifies. Characterized by cutting the lead terminal portion from the frame.

(Operation)

According to the present invention, a gas detection element connected to a lead terminal is arranged between both legs of a base having a U-shaped square cross section, and the opening of the U-shaped square base is covered with a U-shaped explosion-proof net. However, by making the external shape of the gas sensor rectangular, the space efficiency of the gas sensor is improved.

Further, according to the present invention, a gas sensor can be completed by using a lead frame in a method of manufacturing a gas sensor, positioning the gas detection element by the lead frame, and putting a component material into an assembly line using the lead frame. .

〔Example〕

Next, an embodiment of the present invention will be described in detail with reference to the drawings. 1 to 7 show one embodiment of the present invention, and show a process of manufacturing a gas sensor using a lead frame.

In the manufacturing method according to this embodiment, first, as shown in FIG. 1 (A), one good conductor metal plate is punched out by press working, and as shown in FIG.
5 and a support piece 6 having a concave portion 6a for positioning a gas detection element.
To form a lead frame 1 composed of the ribs 7 and 8. As shown in FIG. 1 (A), the lead frame 1 is formed with lead terminals 2 to 5, a support piece 6, and members 7, 8 at a constant pitch. When punching out the lead terminals 2 to 5, the support piece 6, and the joints 7, 8, the support piece 6 has a gas detecting element positioning recess 6a.
Are formed at the same time, it is possible to easily obtain the position accuracy of the tip of the support piece 6, that is, the concave portion 6a for positioning the gas detection element and the lead terminals 2 to 5.

Next, the gas detecting element 9 shown in FIG.
Is supplied to the gas detecting element positioning concave portion 6a. The gas detecting element 9 is provided with a gas sensitive body 10a of a tin oxide based semiconductor on one surface of a sensor substrate 10 in combination with a pair of electrodes 11 and 13, and an electric heater (FIG. 1) on the other surface of the sensor substrate 10. Are hidden and cannot be seen), and a pair of electrodes 12, 14 to which the electric heater is connected are provided so as to penetrate the sensor substrate 10 and be exposed on one surface. The gas detecting element 9 is set in the gas detecting element positioning concave portion 6a of the support piece 6 so that the gas sensing element 10a faces the upper surface, and then the electrodes 11 to 14 and the lead terminals 2 to 5 of the gas detecting element 9 are connected. The conductor wire 15
Bonding and connection are made with .about.18. This state is the second
FIG. (C) shows an enlarged view.

The lead frame 1 formed as shown in FIG. 2 (C) is inserted into a mold, and as shown in FIG.
Are inserted into a mold of a resin molding machine, and synthetic resin made of an insulating material is injected and filled so as to include the base of the lead terminal, thereby insert-molding a 19-shaped U-shaped base. In the base 19, lead terminals 2 to 5 are insert-molded in a U-shaped base 19a and ribs 19b are formed on both side surfaces of the base 19a. Steps 19c1 and 19d1 are provided on the outer periphery of both legs 19c and 19d of the base 19, respectively.

After the lead frame 1 is inserted into the mold and the base 19 is insert-molded, the members 7, 8 which are not required as a product are cut from the dashed lines P1, 2 shown in FIG. 3 (B), and are simultaneously supported. The lead frame 1 to which the pieces 6 are connected is cut from a portion indicated by a chain line P3. The state cut at the P1 to P3 parts is the fourth
As shown in the drawing, the base 19 is supported by lead terminals 2 to 5 connected to one side of the lead frame 1, and the gas detection element 9
Are supported by lead terminals 2 to 5 by conductor wires 15 to 18.

The explosion-proof net 20 shown in FIG. 5 is supplied to the base 19 from which an unnecessary part is cut off as shown in FIG. The explosion-proof net 20 is formed in a double U-shaped square shape by pressing from a stainless steel wire mesh hoop material. The explosion-proof net 20 is a base as shown in FIG.
It is covered so as to cover the 19 openings. At this time, the side of the base 19 of the explosion-proof net 20 that contacts the legs 19c and 19d
It fits into the step parts 19c1 and 19d1 of 9c and 19d. In addition, the ends of the two leg pieces of the explosion-proof net 20 are pushed into the ribs 19b of the base 19a of the base 19 until they are raised, and the ribs 19b are melted by heating both pole pieces of the explosion-proof net 20, so that the stitches of the explosion-proof net 20 are joined. After infiltrating the melted resin, it is solidified and fixed.

After fixing the explosion-proof net 20 to the base 19, the lead terminals 2 to 5 are cut from the lead frame 1 as shown in FIG.

In the gas sensor formed by the manufacturing process described above, the gas detection element is connected to the lead terminal penetrating the base of the base having the U-shaped cross section by a conductor wire, and the opening is formed in the opening of the base having the U-shaped cross section. By being formed by covering the U-shaped square explosion-proof net, the external shape becomes square and narrow.

In the above-described embodiment, the gas sensing element using a gas sensing element made of a metal oxide semiconductor has been described. However, the present invention is not limited to this embodiment, and a contact that requires only two lead terminals may be used. It is also applicable to combustion type.

〔The invention's effect〕

As described above, according to the present invention, a support that has a gasket detecting element positioning recess connected to the support and a lead terminal located on both sides of the support is provided. A lead frame is formed by punching a good conductor metal plate, and the gas detection element is placed in the gas detection element positioning recess of the support piece of the lead frame, and the electrode of the gas detection element and the lead terminal are connected by a conductor wire. connection,
An explosion proof formed in a U-shape, which integrally forms and attaches the lead terminals of the lead frame to a base having a U-shaped cross section, cuts a support piece from the lead frame, and covers an opening of the base having a U-shaped cross section. Covering the base with the base, heating the fitting portion between the explosion-proof net and the base, allowing the melted base resin to penetrate into the stitches of the explosion-proof net and cooling and solidifying, and then cutting the lead terminal part from the lead frame,
The gas sensor can be easily assembled simply by putting component materials into the assembly line.

A base having a U-shaped cross section, a lead terminal penetrating the base of the base, a gas detection element connected by a lead terminal located between both legs of the base having the U-shaped cross section, The gas sensor is constituted by a U-shaped square explosion-proof net covering the opening of the base, so that a gas sensor with a rectangular external shape and a thin width can be obtained, and the installation space is small and the gas sensor has good space efficiency. Can be provided.

[Brief description of the drawings]

1 to 7 show a manufacturing process of a gas sensor according to an embodiment of the present invention. FIG. 1 (A) is a perspective view of a lead frame, and FIG. 1 (B) is a view of FIG. 1 (A). FIG. 2 (A) is an enlarged view of a gas detection element, FIG. 2 (B) is a perspective view showing a state where the gas detection element is set on a lead frame and bonded, and FIG. 2 (C). Is an enlarged view of a main part of FIG. 2 (B), FIG. 3 (A) is a perspective view showing a state where a base made of a synthetic resin is insert-molded on a lead frame, and FIG. 3 (B) is a view of FIG. 3 (A). 4) is a perspective view showing a state in which the support is cut from the lead frame, FIG. 4 (B) is an enlarged view of a main part of FIG. 4 (A), and FIG.
Fig. 6 is a perspective view of the explosion-proof net, Fig. 6 is a perspective view showing a state where the explosion-proof net is put on the base and fixed, and Fig. 7 is a perspective view showing a state in which the lead terminals are cut off from the lead frame. (A), (B) and FIGS. 9 (A), (B)
FIG. 1 is a plan view and a partially cutaway side view showing different conventional examples. 1: Lead frame, 2 to 5: Lead terminal, 6: Supporting piece, 6a: Gas detecting element positioning recess, 7, 8: Housing, 9: Gas detecting element, 11 to 14: Electrode, 15 to 18: Conductor Wire, 19: base, 20: explosion-proof net.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenji Ishikura 1-1-1, Tanabe Shinda, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (56) References JP-A-60-29649 (JP, A) 1964-18053 (JP, A)

Claims (2)

(57) [Claims] 1. A base having a U-shaped cross section, a lead terminal passing through a base of the base, a gas detection element connected by a lead terminal located between both legs of the base having a U-shaped cross section, and the cross section U covering the opening of the U-shaped square base
A gas sensor comprising an explosion-proof net formed in a square shape. 2. A good conductor metal plate is punched out of a crosspiece that bridges the whole, a support piece having a gas detection element positioning recess connected to the crosspiece, and lead terminals located on both sides of the support piece. Forming a lead frame, mounting the gas detection element in the gas detection element positioning recess of the support piece of the lead frame, connecting the electrode of the gas detection element and the lead terminal by a conductor wire, The lead terminal is integrally formed and attached to a base having a U-shaped cross section, a support piece is cut from the lead frame, and an explosion-proof net formed into a U-shape that covers an opening of the base having the U-shaped cross section is attached to the base. Heat the mating part between the explosion-proof net and the base, allow the melted base resin to penetrate the stitches of the explosion-proof net, cool and solidify, and then cut the lead terminals from the lead frame. Method of manufacturing a gas sensor characterized.