JPS6123788Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a terminal portion of various atmosphere detection plugs such as an oxygen sensor, a gas sensor, or a temperature sensor.

An atmosphere detection element consisting of a pellet-shaped oxide semiconductor element fixed to the end face of an insulating tube sealed to the metal outer casing so as to be located near the inner bottom surface of the metal outer casing provided with air circulation holes detects the surrounding gas. , various atmosphere detection plugs that react with the atmosphere such as temperature and generate electric signals from lead wires buried in the atmosphere detection element and held by the insulated tubes to external instruments, Although they are widely used in various exhaust gas treatment and control devices, including automobiles, conventional ones have had problems with the durability of the connection portions near the ends of the lead wires with electrical wires that conduct electricity to instruments.

In other words, the area near the end face of the insulating tube where the pellet-shaped semiconductor device is fixed is required to be as thin and thin as possible from the viewpoint of the response and initial activation of the semiconductor device, so the diameter of the entire insulating tube is reduced. ,
Therefore, the diameter of the terminals connected to the electric wire on the other end surface is also small, making it difficult to provide sufficient mechanical strength to the terminals. This is due to the recently developed four pairs, one each derived from an N-type oxide semiconductor and a P-type oxide semiconductor, which are sensitive to the partial pressure of oxygen in exhaust gas and both have temperature dependence in the same direction.
A temperature-compensated type consisting of a 4-terminal structure in which main lead wires are connected in series, or a 3-terminal structure in which one lead wire of each of the N-type oxide semiconductor and P-type oxide semiconductor of the above four is connected in the middle. The above-mentioned difficulty was particularly great in the case of exhaust gas oxygen detection valves due to the increased number of terminals.

The present invention solves the above-mentioned difficulties, and will be described below with reference to the drawings, taking as an example the temperature-compensated exhaust gas oxygen detection plug having the above-mentioned three terminals.

In the figure, 1 is either an N-type or P-type oxide semiconductor element that is sensitive to oxygen concentration, and in combination with one of other types of oxide semiconductor elements (not shown here), a temperature-compensated exhaust gas oxygen Functions as a detection element. 2 is a lead wire made of thin platinum or heat-resistant nickel wire implanted in the oxide semiconductor element 1, and is connected in series with a lead wire implanted in another type of semiconductor element (not shown) to form a three-terminal type. . 3 is a heat-resistant insulating tube made of high alumina porcelain or the like, and has a recess 3a at its tip for seating and protecting the pair of semiconductor elements 1, and three lead wires 2 are inserted through the recess into the other end 3c. It has a through hole 3b located on a first circumference centered on the central axis and sealed with a heat resistant adhesive 4. Reference numeral 5 designates a metal outer case in which the insulator 3 is sealed and the oxide semiconductor element 1 is attached to a location where the oxygen concentration is to be measured in an exhaust gas purification device, etc., and a plurality of metal cases are used to bring the semiconductor element 1 into direct contact with the exhaust gas. A flow path 5a is provided. 6 is the other end 3c of the insulator
It is made of an insulating material such as porcelain or synthetic resin fixed in a large-diameter recess 3d provided in the recess 3d, and the three lead wires 2 and the core wire 8a of the electrical wire 8 extending from the external instruments are inserted through the core wire 8a and both are brazed or bonded together. This is an insulated joint having a metal terminal tube 7 that is connected by crimping from the outside. so that the inner surface 2a in the centripetal direction is brought into contact with the inner diameter surface of the terminal tube 7 also in the centripetal direction,
Similarly to the first circumference, the second circumference is centered around the central axis and is set larger than the first circumference. 9 insulates the respective connection portions of the lead wire 2 and the electrical wire core wire 8a by the metal terminal tube 7;
A protective jacket made of a flexible insulating material such as rubber is fitted between the other end 3c of the insulating tube and the wire 8 for protection.

As described above, the present invention includes a metal terminal tube drawn out from an oxide semiconductor and connecting a plurality of lead wires and a core wire of electrical wire, respectively, which are located on a first circumference with the central axis as the center. As with the circumference, the lead wires are arranged on a larger circumference, with the center axis as the center, and the inner surface of each lead wire in the centripetal direction is in contact with the inner diameter surface of the metal terminal tube, which is also in the centripetal direction. from,
The terminal tubes are drawn toward the outer circumference of the insulating joint, expanding the insulation gap between adjacent metal terminal tubes, so larger diameter ones are used to satisfy the mechanical strength of these terminal tubes. However, there is no need to increase the size of the oxide semiconductor element, and the diameter near the end face of the insulating tube to which the semiconductor element is fixed can be reduced to maintain the desired responsiveness and initial activation. The lead wire and the core wire of the electrical wire can be connected easily and reliably because it is attached to an insulating joint that is inserted and fixed to the end face of the insulating pipe. Since it is insulated and protected by the protective jacket, it has excellent effects in terms of both performance and mass production.

Note that the above explanation was about a 3-terminal structure, but the 4-terminal structure
It can be applied to a terminal structure as well as to an atmosphere detection plug using only one semiconductor element.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a quarter half of the atmosphere detection plug of the present invention, and FIG. 2 is a cross-sectional view taken along the line E--I of FIG. 1...Atmosphere detection element, 2...Lead wire, 3...
...Insulating porcelain tube, 3a...One end surface, 3b...Through hole, 3c...Other end surface, 3d...Large diameter recess at the other end, 4...Heat-resistant adhesive, 5...Metal outer casing, 6
... Insulation joint, 7 ... Terminal tube, 8 ... Electric wire, 8a
... Heart line, 9... Protective cloak.

Claims (1)

[Scope of utility model registration request] An atmosphere detection element 1 is fixed to one end surface 3a,
An insulated tube 3 in which a plurality of lead wires 2 implanted in the sensing element are inserted through each through hole 3b to the other end surface 3c.
in a large-diameter recess 3d provided at the other end 3c of the insulating tube, in which the lead wire 2 is connected to an electric wire 8 that conducts to external instruments. Similarly, from the first circumference, also centered on the central axis, so as to come into contact with the inner surfaces in the centripetal direction of each of the plurality of lead wires 2 protruding on the first circumference centered on the central axis, in the recessed portion. Also big 2nd
An insulating joint 6 having a plurality of metal terminal tubes 7 located on the circumference of the metal terminal tube 7 is fitted, and the core wire 8a of the electrical wire is inserted into each metal terminal tube 7, and the metal terminal tube 7 is attached by brazing or the like. The lead wires 2 are respectively connected to the core wires 8a of the electrical wires through the wires, and a protective jacket 9 for insulating and protecting these connections is fitted between the other end 3c of the insulating tube and the electrical wires 8. Detection plug.