JPH0629730Y2 - Gas sensor mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a structure in which a gas sensor having a directional gas sensing element is attached to an exhaust pipe by screwing.

(Prior Art) A gas sensor for detecting a gas concentration in exhaust gas in an internal combustion engine or various combustion equipment such as a blast furnace is disclosed in, for example, Japanese Patent Laid-Open No.
No. 0-158346 and No. 60-227158 are known.

By the way, such a gas sensor is generally attached to the exhaust pipe by screwing (threading) a male screw portion provided on the outer periphery of the main body of the metal shell to a female screw portion provided on the gas sensor mounting portion of the exhaust pipe. It is like this.

(Problems to be solved by the invention) However, in such a mounting structure in which the male screw portion provided on the outer peripheral portion of the main body of the metal shell is screwed to the female screw portion provided on the gas sensor mounting portion of the exhaust pipe. In this case, there is no choice but to rely on manual attachment (screw tightening), and thus there is a problem that productivity deteriorates.

That is, in the above-mentioned mounting structure, it is difficult to tighten the screw with a machine because the sensor itself provided with the lead wire must be rotated to screw the male screw portion into the female screw portion. Further, in such a mounting structure, when the gas sensor includes a directional gas sensing element (for example, a thick film type gas sensing element as disclosed in the above publication), the gas sensing element is arranged with respect to the exhaust pipe. There was also a problem that it was difficult to set the direction.

By the way, the directional gas-sensitive element has a preferable arrangement direction with respect to the exhaust pipe, and unless the gas-sensitive element is attached according to the arrangement direction, the gas sensor cannot exhibit a predetermined detection performance.

Some sensors installed in the exhaust pipe are mounted on the exhaust pipe by using a mounting flange provided on the outer peripheral portion of the main body of the metal shell (Invention Society Publication Technical Report No. 85-12).
No. 403, No. 85-15260, etc.), in the case of this mounting structure, since the mounting flange is bolted to the exhaust pipe, it can be mechanically screwed, but also of a gas sensing element having directionality. It is difficult to set the placement direction.

In view of this, the present invention provides a gas sensor mounting structure that allows a machine to perform screw tightening when mounting a gas sensor to an exhaust pipe, and at the same time, to set the direction of arrangement of a gas-sensitive element having directionality when mounting the gas sensor. The purpose is to do.

(Means for Solving Problems) In order to achieve the above object, the present invention forms a flange for fitting to the exhaust pipe side on the outer periphery of the main body of the metal shell of a gas sensor having a directional gas sensing element. An outer peripheral surface of the fitting flange is shaped to define a disposing direction of the gas sensing element, and a fitting hole of the fitting flange having the same axis as the gas sensor insertion hole in the gas sensor mounting portion of the exhaust pipe and the fitting. A female screw hole having a diameter larger than that of the fitting hole is formed, the inner peripheral surface of the fitting hole has the same shape as the outer peripheral surface shape of the fitting flange, and the protective cylinder side of the metal shell of the gas sensor is the gas sensor. The fitting flange is fitted into the fitting hole, and the male threaded portion of the nut loosely fitted to the outer peripheral portion of the metallic shell on the sleeve side is screwed into the female threaded hole. Fix the gas sensor to the exhaust pipe. It is characterized by that.

(Operation) According to the present invention, the nut for screwing and fixing the gas sensor to the exhaust pipe can be tightened by a screw tightening machine, and the outer peripheral surface of the fitting flange and the inner peripheral surface of the fitting hole are Since the same shape is used to define the disposition direction of the gas-sensitive element, the disposition direction of the gas-sensitive element with respect to the exhaust pipe can be set at the same time as mounting the gas sensor having the directional gas-sensitive element.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 2 indicates an exhaust pipe of an internal combustion engine, a blast furnace, etc., and 1 indicates a gas sensor attached to a gas sensor attachment portion of the exhaust pipe 2.

The gas sensor 1 has a fitting flange 7 on the exhaust pipe 2 side formed at the center of the outer peripheral portion of the main body 3 of the metal shell 6 composed of the main body 3, the sleeve 4, and the protective cylinder 5.

The gas sensor 1 according to the present embodiment includes a directional gas sensitive element (thick film type gas sensitive element) 9, and the fitting flange 7 defines the arrangement direction of the gas sensitive element 9 in the gas sensor 1. A shape having a function (so-called a marker for the so-called gas sensing element 9) is preferable. Therefore, in this embodiment, the shape of the outer peripheral surface 8 of the fitting flange 7 is set to the second shape.
As shown in the figure, the base plate-shaped pentagonal shape is simple and the arrangement direction of the gas sensitive element 9 can be defined. In this case, the acute angle portion 10 of the outer peripheral surface 8 is arranged on the axis of the gas sensitive element 9.

A sensor mounting boss member 11 is fixedly mounted on a peripheral wall portion of the exhaust pipe 2 which serves as a sensor mounting portion. For fixing the boss member 11 to the exhaust pipe 2, the outer peripheral small diameter portion 12 is fixed to the exhaust pipe 2.
The outer peripheral large-diameter portion 14 is welded to the peripheral wall of the exhaust pipe 2 while being fitted into the mounting hole 13 formed in the peripheral wall of the exhaust pipe 2. The gas sensor insertion hole 16 is formed in the center of the boss member 11.
And the fitting hole 17 of the fitting flange 7 and the female screw hole 1
8 and 8 are successively formed. In this case, the fitting hole 17
Has a larger diameter than the gas sensor insertion hole 16, and the female screw hole 18 has a larger diameter than the fitting hole 17.

The shape of the inner peripheral surface 19 of the fitting hole 17 is the same as the shape of the outer peripheral surface 8 of the fitting flange 7. In this embodiment, as shown in FIG. There is. Therefore, when the fitting flange 7 is fitted into such a fitting hole 17, those acute-angled portions 10 and 20 (which serve as markers in the arrangement direction of the gas sensitive element 9) are engaged. When the boss member 11 is fixed to the exhaust pipe 2, such a fitting hole 17 is arranged such that its arrangement direction (the direction of the acute angle portion 20 with respect to the exhaust pipe 2) is aligned with the arrangement direction of the gas sensitive element 9 in the exhaust pipe 2. To be

On the other hand, in FIG. 1, reference numeral 21 denotes a sensor fixing nut that is loosely fitted to the outer peripheral portion of the sleeve 4 of the metal shell 6 of the gas sensor 1 in advance, and this is a male screw portion screwed into the female screw hole 18. 22. The gas sensor 1 having the configuration described above is attached to the exhaust pipe 2 in the following manner.

That is, the protective cylinder 5 side of the metal shell 6 of the gas sensor 1 is inserted into the gas sensor insertion hole 16, and the fitting flange 7 is fitted into the fitting hole 17 so that the acute angle portions 10 and 20 are engaged as described above. To do.

After that, the nut 21 is rotated by a screw tightening machine (not shown), and the male screw portion 22 is screwed into the female screw hole 18. The gas sensor 1 is fixed to the exhaust pipe 2 by tightening the nut 21 until the end surface 23 of the male screw portion 22 contacts the end surface 24 of the fitting flange 7.

Thus, in the above mounting structure, since the gas sensor 1 itself provided with the lead wire 25 is not rotated, it does not interfere with the tightening of the nut 21 by the screw tightening machine, and the gas sensor 1 is mounted. At the same time, the arrangement direction of the gas sensitive element 9 (direction orthogonal to the axis of the exhaust pipe 2)
Can be set.

(Effect of the Invention) As is apparent from the above description, according to the present invention, the fitting flange provided on the gas sensor side is fitted into the fitting hole provided on the exhaust pipe side, and is loosely fitted and mounted on the gas sensor side. Since the external thread portion of the nut is provided on the exhaust pipe side so as to be screwed into the screw hole, it is possible to use a screw tightening machine when screwing the gas sensor to the exhaust pipe, thereby improving productivity.

Further, according to the present invention, since the outer peripheral surface of the fitting flange and the inner peripheral surface of the fitting hole have the same shape that defines the arrangement direction of the gas-sensitive element, mounting of a gas sensor having a directional gas-sensitive element is possible. At the same time, the arrangement direction of the gas sensitive element with respect to the exhaust pipe can be set.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a mounting structure of a gas sensor according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1 of a fitting flange formed on a metal shell of a gas sensor, FIG. 3 is a plan view of a boss member provided on the exhaust pipe. 1 ... Gas sensor, 2 ... Exhaust pipe, 3 ... Main body, 4 ...
Sleeve, 5 ... Protective cylinder, 6 ... Metal fitting, 7 ... Mating flange, 8 ... Mating flange outer peripheral surface, 9 ... Gas sensitive element, 11 ... Boss member, 16 ... Gas sensor insertion Hole,
17 ... Fitting hole, 18 ... Female screw hole, 19 ... Inner peripheral surface of fitting hole, 21 ... Nut, 22 ... Male thread portion.

Claims (2)

[Scope of utility model registration request] 1. A fitting flange to an exhaust pipe side is formed on an outer peripheral portion of a main body of a metal shell of a gas sensor having a directional gas sensing element, and an outer peripheral surface of the fitting flange is disposed in an arranging direction of the gas sensing element. On the other hand, on the other hand, a fitting hole of the fitting flange having the same axis as the gas sensor insertion hole and a female screw hole having a larger diameter than the fitting hole is formed in the gas sensor mounting portion of the exhaust pipe, The inner peripheral surface of the fitting hole has the same shape as the outer peripheral surface of the fitting flange, the protective cylinder side of the metal shell of the gas sensor is inserted into the gas sensor insertion hole, and the fitting flange is formed into the fitting hole. Fitting, and further mounting the gas sensor by fixing the gas sensor to the exhaust pipe by screwing the male screw part of the nut loosely fitted on the outer peripheral part of the metal shell on the sleeve side into the female screw hole. Construction. 2. The gas sensor according to claim 1, wherein the outer peripheral surface shape of the fitting flange and the inner peripheral surface shape of the fitting hole are base disk-shaped pentagons. Mounting structure.