JP2002107333A - Mounting structure for gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure with which a gas sensor used for detecting components to be detected in a gas can be attached easily to a gas circulation pipe. SOLUTION: When an oxygen sensor 2 is inserted, into and passed through a cylindrical part 104 in an evacuation pipe 100, a lower end face 18 of a diameter-expanding part 12 in a main body fitting 4 comes into contact with each insertion and with a passage part 114 of an elastic member 112. As the outer wall part of the part 12 is passed through each part 114, the elastic member 112 is pressed by the part 12, and the elastic member 112 is elastically deformed in the outer circumferential direction of the cylindrical part 104 via a cutout part 110. When the oxygen sensor 2 is inserted and passed, the lower end face 18 of the part 12 comes into contact with the step part 106 of the cylindrical part 104, and the elastic member 112 comes into contact with an upper end face 16 of the part 12. As a result, due to the elastic force of the elastic member 112, the part 12 is set to a state with its being sandwiched between the step part 106 of the cylindrical part 104 and the elastic member 112, and the oxygen sensor 2 being fixed to the evacuation pipe 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas sensor mounting structure mounted on a gas flow pipe through which a gas flows to detect a component to be detected in the gas.

[0002]

2. Description of the Related Art Conventionally, in order to control, for example, an internal combustion engine for an automobile, it is attached to a gas flow pipe such as an exhaust pipe.
Components to be detected in flowing gas (for example, oxygen, NOx
Etc.) are known.

[0003] Such a gas sensor is usually
A detection element having a detection section formed at the tip, and a cylindrical metal shell holding the detection element in a state where the detection section is protruded outward, while the gas flow pipe has a detection section of the detection element. A dedicated mounting hole is provided for mounting the gas sensor in a state in which the gas sensor is projected into the pipe.

Here, the following three methods can be cited as typical methods for attaching the gas sensor to the gas flow pipe. (1) A screw thread is provided on the outer peripheral surface of the metal shell, and a screw groove corresponding to the screw thread of the metal shell is provided on the inner wall of the mounting hole of the gas flow pipe, so that the metal shell (therefore, the gas sensor itself).
Method of screwing into the mounting hole.

(2) A screw insertion hole for inserting a screw member is provided, and a flange configured to abut around a mounting hole of the gas flow pipe is formed integrally with the metal shell of the case. A method of mounting by projecting on the outer circumference, inserting a screw member into the screw insertion hole, and tightening and fixing the flange to the gas flow pipe.

(3) An outwardly protruding flange portion is formed on the outer peripheral surface of the metal shell, and the distal end side (the detection portion side of the detection element) is formed.
Is inserted into the mounting tubular portion protruding from the gas flow pipe, and the end portion is brought into contact with the flange portion. In addition, a thread is provided on the outer periphery of the cylindrical portion for attachment. Then, a cap nut having a thread groove corresponding to the screw thread is inserted through the outside of the metal shell, and is fastened and fixed to a tubular portion for attachment.

[0007]

Problems to be Solved by the Invention (1)-
In the method (3), a special tool is required to tighten the metal shell and the screw member in order to fix the gas sensor to the gas flow pipe. However, when the gas sensor is mounted in the mounting hole of the gas flow pipe by piercing a narrow space, for example, when the gas flow pipe is complicated, a tool that can perform work in such a space is required, and the shape of the tool is required. And types were restricted. In addition, there is a problem that the mounting operation itself is troublesome.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is provided with a gas sensor attached to an internal combustion engine or the like for detecting a component to be detected in a gas flowing through a gas flow pipe. So that it can be easily mounted.

[0009]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a shaft having a detection portion for detecting a component to be detected in a gas at a front end side. -Shaped detection element, and a gas sensor having a cylindrical metal shell for gripping the detection element, such that the detection section comes into contact with the gas to be measured, in a mounting hole formed in the gas flow pipe. A mounting structure of a gas sensor for inserting and fixing, wherein an outwardly protruding enlarged-diameter portion is formed on an outer periphery of the metal shell, and an end face on a distal end side of the enlarged-diameter portion is attached to the gas flow pipe. The elastic member, which is partially fixed to the gas flow pipe, is brought into contact with a seat formed on the inner wall of the mounting hole and an end surface on the rear end side of the enlarged diameter portion. The gas sensor is fixed to the mounting hole via a member. .

Here, as the axial detection element provided in the gas sensor of the present invention (claim 1), for example, an element configured to electrically detect a component to be detected in a gas is used. Examples thereof include an element formed of a conductive solid electrolyte body and formed in a long plate shape (for example, a detection element included in a λ-type oxygen sensor), an element formed in a bottomed cylindrical shape, and the like.

That is, in the gas sensor mounting structure of the present invention (claim 1), the enlarged diameter portion of the metallic shell is attached to the mounting hole seat by utilizing the elastic force of an elastic member partially fixed to the gas flow pipe. The gas sensor is fixed to the mounting hole of the gas flow pipe by pressing the gas sensor. Therefore, the gas sensor can be easily and firmly attached to the attachment hole of the gas flow pipe without using a dedicated tool or the like for fixing the gas sensor.

Here, various methods are conceivable in order that the elastic member can be brought into contact with the enlarged diameter portion of the metal shell with a part fixed to the gas flow pipe. As described above, by extending the periphery of the mounting hole outward, a cylindrical portion is formed in the gas flow pipe, and at a part of the outer wall of the cylindrical portion, it is orthogonal to the central axis of the cylindrical portion. It is also possible to form a notch cut out until reaching the inside of the cylinder along the direction, and fix the elastic member in a state of being inserted through this notch.

That is, according to the present invention (claim 2), the elastic member is fixed to the gas flow pipe with the elastic member inserted through the notch so that the elastic member is disposed within the cylindrical portion of the gas flow pipe. Is what you do. With this configuration, the elastic member disposed in the cylindrical portion of the cylindrical portion comes into contact with the end face on the rear end side of the enlarged diameter portion of the gas sensor, and the enlarged diameter portion is connected to the seat portion as described above. Can be firmly pressed.

Then, such notches are formed in the outer wall of the cylindrical portion so as to face each other, as described in claim 3.
If provided, the elastic member can be fixed by being inserted into each of the cutout portions, and furthermore, the expanded portion can be firmly pressed against the seat from both sides of the tubular portion by these elastic members.

Further, as another method for allowing the elastic member to abut on the enlarged diameter portion of the metal shell with a part of the elastic member fixed to the gas flow pipe, the gas flow pipe may be provided as described in claim 4. In order to form a tubular portion by extending the periphery of the mounting hole outward, and to fix a part of the elastic member to an end of the tubular portion opposite to the gas flow pipe. And a hooking portion for hooking the open end side of the elastic member pulled out from the fixing portion.

That is, in the present invention (claim 4), a part of the elastic member is fixed to the gas flow pipe through the fixing portion of the cylindrical portion,
The end of the elastic member opposite to the fixed portion is hooked on the hook of the tubular portion. Then, in order to fix the gas sensor to the gas flow pipe, for example, the gas sensor is arranged so that its enlarged portion contacts the seat of the cylindrical portion, and then the elastic member is moved to the rear end side of the enlarged portion. The end of the elastic member on the side opposite to the side fixed to the fixing portion may be hooked on the hooking portion and fixed.

Also in this case, the gas sensor can be firmly fixed to the gas flow pipe by utilizing the elastic force of the elastic member. Further, as described in claim 5, the elastic member may be pulled out from the fixed portion in two directions, and both open ends of the pulled out elastic member may be hooked on the hook portions, respectively.

That is, the elastic members respectively drawn out from the fixing portions are passed around the metallic shell of the gas sensor, and the like.
Each end is hooked and fixed to the hooking part on the opposite side to the fixing part. With this configuration, the expanded portion can be firmly pressed against the seat from both sides of the metal shell by the pulled-out elastic member.

The elastic member is made of a rod-shaped metal material having toughness.
In addition, a portion that contacts the rear end of the enlarged diameter portion may be curved so that the gas sensor can be pressed toward the front end. With this configuration, the elastic member comes into contact with the enlarged diameter portion while being flexed by toughness, and the resilient force firmly presses the enlarged diameter portion against the seat portion. In addition, since the curved portion can more strongly press the enlarged diameter portion, the gas sensor can be firmly fixed to the gas flow pipe.

Further, the elastic member may be formed of a tough rod-shaped metal material, and may be formed in a C-shape which is partially open. . With this configuration, the elastic member can be easily fixed to the above-described tubular body of the gas flow pipe by fitting the elastic member through the opened portion of the elastic member.

On the other hand, the seat of the tubular body of the gas flow pipe may be formed to have a tapered shape. Here, forming the seat portion into a tapered shape means, for example, forming an inclined surface toward the inside of the gas flow tube in the seat portion. On the other hand, the end face on the front end side or the rear end side of the enlarged diameter portion may be formed to have a tapered shape. Here, forming the end surface on the front end side of the enlarged diameter portion into a tapered shape means, for example, forming an outwardly inclined surface from the front end side to the rear end side.
Further, forming the end surface on the rear end side of the enlarged diameter portion into a tapered shape refers to, for example, forming an outward inclined surface from the rear end side to the front end side.

As described above, the seat of the cylindrical body is formed in a tapered shape (claim 8), or the end surface on the tip end side of the enlarged diameter portion is formed in a tapered shape (claim 9). The positioning of the gas sensor at the time of insertion into the body is facilitated, and after insertion, the gas sensor is firmly fixed without shifting.

Further, by making the end surface on the rear end side of the enlarged diameter portion tapered, the elastic direction of the elastic member is, for example, in a plane perpendicular to the central axis of the gas sensor and in a direction toward this central axis. In the case of (in other words, the direction toward the central axis), since the elastic component of the component toward the tip side along the central axis of the gas sensor is generated, the enlarged diameter portion can be firmly pressed against the seat. .

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a gas sensor mounting structure according to a first embodiment of the present invention;
Will be described with reference to the drawings. In each of the embodiments, the mounting structure of the oxygen sensor to be mounted on the exhaust pipe of the internal combustion engine for a vehicle has been embodied.

(First Embodiment) FIGS. 1A and 1B show a mounting structure of an oxygen sensor 2, in which FIG. 1A is a longitudinal sectional view showing a state in which the oxygen sensor 2 is mounted on an exhaust pipe 100, and FIG. The perspective view, (c), shows the AA cross section shown in (a).

The oxygen sensor 2 includes a cylindrical metal shell 4, an insulating protective body 6 disposed in the cylinder of the metal shell 4, and an inside of the insulating protective body 6 with its tip (lower in the figure) protruding. And a detection element 8 having a rectangular cross section and a long plate-shaped oxygen concentration cell element made of an oxygen ion conductive solid electrolyte. Note that the detection element 8 is formed by laminating a heater (not shown) for activating the oxygen concentration cell element.

The metal shell 4 has legs 10 arranged in order from the distal end side, a large-diameter portion 12 projecting outward along a direction perpendicular to the central axis, and a shape extending from the large-diameter portion 12. And a rear end portion 14, which are integrally formed. Among these, the upper end surface 16 of the enlarged diameter portion 12 is a slope having a surface facing upward and outward, while the lower end surface 18 is a slope having a surface facing downward and outward. Also, the rear end 14
Is an inclined surface having a surface facing upward and outward.

In the metal shell 4, the rear end 1
4, the enlarged diameter portion 12, and the leg portion 10 are formed so that the inner diameter becomes smaller in this order. On the inner wall of the metal shell 4, a step portion 20 is formed between the rear end portion 14 and the enlarged diameter portion 12, and a step portion 22 is formed between the enlarged diameter portion 12 and the leg portion 10. ,
Each of these steps 20 and 22 has a slope descending toward the front end side in the cylinder.

Here, such a metallic shell 4 is entirely formed of stainless steel. In order to form the metal shell 4, for example, a metal material (such as stainless steel powder) is injected into a metal mold to obtain a molded article serving as a metal mold, and then the molded article is sintered or the like. A metal injection molding method that completes a metal shell of a predetermined shape by performing the metal injection molding can be used.

The insulating protective body 6 has a substantially cylindrical shape having a flange 24 formed by projecting a rear end side (upper side in the figure) side wall in a direction perpendicular to the central axis. Moreover,
A substantially rectangular insertion hole 26 is formed along the central axis along the cross-sectional shape of the detection element 8, and the detection element 8 is inserted into and held by the insertion hole 26. Here, the detecting element 8 has a detecting portion 8a formed on the front end side (lower side in the figure), and a plurality of (detecting portions) on the rear end side for taking out the electromotive force of the oxygen concentration cell generated by the detecting portion 8a from outside. Four (in the embodiment, four) L-shaped metal terminals 28 are attached via a gripping member 30 or the like.

The insulating protection body 6 holding the detecting element 8 has its distal end peripheral side abutting against the step 22 of the metal shell 4 and has its outer wall abutting against the inner wall of the rear end 14. In this state, it is disposed on the metal shell 4, and further, inside the metal shell 4 in this state, the upper side of the insulating protection body 6, the metal terminal 28
Is filled with a filler material 32 for fixing to the metal shell 4 so as to bury a part of it. The metal terminal 28
Is disposed inside the rear end portion 14 of the metal shell 4. As the filler 32, for example, resin, glass (silica borax glass), or the like can be used.

On the other hand, around the leg 10 of the metal shell 4,
A double protector 34, 36 for protecting the detection portion 8a side of the detection element 8 is fixed by welding or the like, while having a gas flow hole for allowing exhaust gas to flow in and out. The oxygen sensor 2 is configured as described above. Then, in the oxygen sensor 2 configured as described above,
A connector member extending from a control unit of the internal combustion engine (not shown) is externally fitted to the rear end portion 14 of the metal shell 4 in a state where the connector member is connected to the metal terminal 28.
The electromotive force of the oxygen concentration cell detected in a can be taken out.

On the other hand, the exhaust pipe 100 has a circular hole 1.
02 is bored, and the cylindrical portion 104 is fixed to the hole 102. The cylindrical portion 104 is entirely formed of stainless steel (for example, SUS430), and has a tip opening 1.
The protruding portion 108 is formed by projecting the inner wall of the 04a side inward through the step portion 106 having a slope descending toward the distal end side in the cylinder. Also, on the side wall on the rear end side, notches 110 cut out until reaching the inside of the cylinder along a direction orthogonal to the central axis of the cylindrical part 104 are opposed to each other with this central axis interposed therebetween. Two portions are formed.

The cylindrical portion 104 is formed so as to accommodate a part of the rear end portion 14 of the metal shell 4 of the oxygen sensor 2, the portion extending to the enlarged diameter portion 12 and the leg portion 10. On the rear end side of the cylindrical portion 104, a toroidal rod-shaped metal material is used, and as shown in FIGS. Inside, an elastic member 112 formed in a substantially U-shaped (C-shaped ring) is attached via a notch 110. The elastic member 112 is inserted into the insertion portion 1 that is inserted into the cutout portion 110.
14 and a common support portion 116 extending from an end portion (upper side in FIG. 1C) of each insertion portion 114. Further, each insertion portion 114 is substantially L-shaped so that the other ends thereof face each other.
A bent portion 118 bent in a letter shape is formed.

The elastic member 112 thus configured is
Each of the insertion portions 114 is inserted into the notch portion 110 so that a part of the insertion portion 114 projects into the cylinder of the cylindrical portion 104, and
And, the bent portion 118 is attached to the cylindrical portion 104 in a state in which the bent portion 118 is in contact with the outer wall of the cylindrical portion 104.

To attach the oxygen sensor 2 to the exhaust pipe 100 configured as described above, the oxygen sensor 2 is
What is necessary is just to insert it through this cylindrical part 104 via the detection part 8a side of the detection element 8 through the rear end side opening part of the cylindrical part 104 first. When the oxygen sensor 2 is inserted, first, the lower end surface 18 of the enlarged diameter portion 12 of the metal shell 4 is
Then, as the outer wall portion of the enlarged diameter portion 12 passes through each insertion portion 114, the elastic member 112 is pressed by the enlarged diameter portion 12, and the elastic member 112 is notched. The cylindrical portion 104 is elastically deformed in the outer peripheral direction through the portion 110.

When the oxygen sensor 2 is further inserted, the lower end surface 18 of the enlarged diameter portion 12 finally becomes the stepped portion 1 of the cylindrical portion 104.
06, and the elastic member 112 comes into contact with the upper end surface 16 of the enlarged diameter portion 12. In this state, the upper end surface 16 of the enlarged diameter portion 12 is pressed downward by the elastic force (restoring force) of the elastic member 112. As a result, the enlarged diameter portion 12 is formed by the step portion 106 of the cylindrical portion 104 and the elastic member 112.
, And the oxygen sensor 2 is fixed to the exhaust pipe 100 (the tubular portion 104). Further, the elastic member 112 is arranged so as to seal a portion of the notch 110 inside the tubular portion 104 in a state where the enlarged diameter portion 12 (the oxygen sensor 2) is fixed.

In this embodiment, the opening 104a at the end of the cylindrical portion 104 corresponds to the "mounting hole" described in the claims.
The step 106 of the cylindrical portion 104 corresponds to a “seat” in the claims. As described above, in the present embodiment, the oxygen sensor 2 is fixed to the exhaust pipe 100 using the elasticity (spring elasticity) of the elastic member 112 only by inserting the oxygen sensor 2 into the cylindrical portion 104 without using a tool or the like. And its operation is very simple. For this reason, the oxygen sensor 2 can be smoothly attached even in a place where the exhaust pipe is arranged in a complicated manner. Further, the attached oxygen sensor 2 is maintained in a fixed state by the elastic member 112, and therefore does not come off the exhaust pipe 100 naturally.

Further, to remove the oxygen sensor 2 from the exhaust pipe 100, the oxygen sensor 2 may be pulled out from the tubular portion 104, and the operation is simple. The lower end surface 18 of the enlarged diameter portion 12 of the metal shell 4 and the cylindrical portion 10
As shown in FIG. 1A, the stepped portion 106 of FIG. 4 has slopes formed so as to correspond to each other, so that the metal shell 4 (oxygen sensor 2) is inserted into the cylindrical portion 104. In this case, positioning becomes easy, and after insertion,
The oxygen sensor 2 is firmly fixed to the exhaust pipe 100 without shifting in the lateral direction (that is, in the in-plane direction orthogonal to the central axis of the oxygen sensor 2).

In the oxygen sensor 2 mounted as described above, the enlarged diameter portion 12 is formed by the elastic member 112 so that the cylindrical portion 1 is formed.
04, and the notch 110 is sealed by the elastic member 112.
The outflow of exhaust gas from 00 is prevented.

(Second Embodiment) FIGS. 2A and 2B show a mounting structure of an oxygen sensor 40, and FIG.
0 (b) is a perspective view of the mounting portion, (c) is a side view of the mounting portion, and (d) is a front view of the mounting portion.

The oxygen sensor 40 differs from the oxygen sensor 2 shown in the first embodiment only in the shape of a part of the metal shell, and the other components are the same. Therefore, the same components as those of the oxygen sensor 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. That is, the oxygen sensor 40 includes the metal shell 42, the insulating protection body 6, and the detection element 8.

The metal shell 42 has legs 10 arranged in order from the tip end, a large-diameter portion 44 projecting outward along a direction perpendicular to the central axis, and a shape extending from the large-diameter portion 44. And a rear end portion 14, which are integrally formed. Of these, the upper end surface 46 of the enlarged diameter portion 44 is a surface orthogonal to the central axis, while the lower end surface 18 is a slope having a surface facing downward and outward. The outer wall portion of the rear end portion 14 on the side of the enlarged diameter portion 44 is a slope having a surface facing upward and outward.

In the metal shell 42, the rear end 1
4, the enlarged diameter portion 44 and the leg portion 10 are formed such that the inner diameter becomes smaller in this order. Further, on the inner wall of the metal shell 42, the step portion 20 is formed between the rear end portion 14 and the enlarged diameter portion 44, and the step portion 22 is formed between the enlarged diameter portion 44 and the leg portion 10. .

The metal shell 42 is entirely made of stainless steel. And the metal shell 42
Can be formed by the metal injection molding method described above. The oxygen sensor 40 is configured as described above. The oxygen sensor 4 configured as described above
At 0, as in the case of the oxygen sensor 2, the connector member extended from the control unit of the internal combustion engine is externally fitted to the rear end portion 14 of the metal shell 42 while being connected to the metal terminal 28. The electromotive force of the oxygen concentration cell detected by the detection unit 8a of the detection element 8 can be extracted.

On the other hand, the hole 10 formed in the exhaust pipe 100
The cylindrical part 120 is fixed to 2. This cylindrical part 1
20 is formed entirely of stainless steel as in the case of the cylindrical portion 104 described above, and the protruding portion 108 is formed by the inner wall on the side of the distal end opening 120a protruding inward via the step portion 106. ing.

A fixing portion 12 for fixing an elastic member 140, which will be described later, is provided at the rear end with the central axis interposed therebetween.
2 and a hook portion 124 for hooking the elastic member 140 are formed. Incidentally, the cylindrical portion 120 is provided with the oxygen sensor 4.
The metal shell 42 is formed so that a part of the enlarged diameter portion 44 of the metal shell 42 and a portion extending to the leg 10 are accommodated.

As shown in FIG. 2 (c) and the like, the fixing portion 122 includes a base 1 projecting from an end of the cylindrical portion 120.
26, and a groove 128 that is open to the outside of the cylindrical part 120 with a part of the base 126. On the other hand, hook 1
Reference numeral 24 denotes the cylindrical portion 12 as shown in FIGS.
The base 130 includes a base 130 protruding from an end of the base 130, and a “C” -shaped hook 132 protruding from both ends of the base 130 and partially open. The hooks 132 are provided so that the opening directions thereof are opposed to each other.

The elastic member 140 is made of a tough rod-shaped metal material, and is formed in an open C-shape. That is, the elastic member 140 is
The two abutting portions 142 that partially abut against each other by pressing the upper end surface 46 of the enlarged diameter portion 44, and a common portion extending from an end portion (right side in FIG. 2C) of the abutting portion 142. Support 14
4 and a rod-like portion 14 extending outward from the other end of each contact portion 142 along a direction orthogonal to the central axis of the elastic member 140 and hooking on the hook portion 124 of the tubular portion 120.
6 and “C” for operating the elastic member 140 from outside
And a grip portion 148 having a character shape.

The contact portion 142 is formed to be curved so as to press the upper end surface 46 of the enlarged diameter portion 44 of the metal shell 42 along the direction in which the oxygen sensor 40 is inserted into the cylindrical portion 120. I have. The elastic member 140 thus configured
The support portion 144 is fixed to the cylindrical portion 120 by disposing the support portion 144 in the groove portion 128 of the fixing portion 122 of the cylindrical portion 120, and each contact portion 142 is an upper end surface of the enlarged diameter portion 44 of the metal shell 42. Each rod-shaped portion 146 is hooked on each hook 132 of the hooking portion 124 of the tubular portion 120 in a state where 46 is pressed.

That is, the exhaust pipe 1 configured as described above
In order to attach the oxygen sensor 40 to the 00 side, first, the oxygen sensor 40 is
The cylindrical portion 120 is first placed on the detecting portion 8a side of the detecting element 8.
And the lower end surface 18 of the enlarged diameter portion 44 of the metal shell 42 is arranged in contact with the step portion 106 of the tubular portion 120. At this time, as shown in FIG.
The oxygen sensor 40 is arranged in a state in which the upper end side protrudes from the cylindrical portion 120.

Next, the portion between the enlarged diameter portion 44 and the rear end portion 14 of the oxygen sensor 40 (the metal shell 42) is inserted into the ring of the elastic member 140 through the open side of the elastic member 140. . The support portion 144 of the elastic member 140
Is fixed to the fixing portion 122 of the cylindrical portion 120 as described above, the contact portion 142 is brought into contact with the upper end surface 46 of the enlarged diameter portion 44 of the metal shell 42, and the operation is performed so as to sandwich each grip portion 148. Then, the bar portion 146 is hooked on the hook portion 124.

In this state, the upper end surface 46 of the enlarged diameter portion 44 is pressed downward by the elastic force (restoring force) of the elastic member 140. As a result, the enlarged diameter portion 44 becomes the cylindrical portion 120.
Is sandwiched between the step portion 106 and the elastic member 140, and the oxygen sensor 40 is connected to the exhaust pipe 100 (the cylindrical portion 12).
0).

Here, in the present embodiment, the opening 120a at the tip end of the cylindrical portion 120 corresponds to the "mounting hole" in the claims. As described above, in the present embodiment, the elastic member 140 is attached after the oxygen sensor 40 is inserted into the cylindrical portion 120 without using a tool or the like.
The same effect as in the first embodiment described above can be obtained, such that the elastic member 40 can be fixed to the exhaust pipe 100 using the elasticity (spring elasticity).

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described first and second embodiments, but can take various forms. For example, the second
In the tubular portion 120 described in the embodiment, the elastic member 14
Two hooks 1 for the hook 124 for hooking
However, if the two hooks 146 of the elastic member 140 are formed so as to be able to hook the two hooks 146, only one hook is required.

In each of the above embodiments, the detection element is formed by using an oxygen ion conductive solid electrolyte mainly composed of zirconia or the like, so that a so-called electromotive force change type gas sensor (oxygen sensor) can be obtained. It is what was constituted. The present invention is not limited to this, and the detection element may be formed using a metal oxide such as titania, so as to be a so-called resistance change type gas sensor (oxygen sensor).

Further, in order to enhance the detection sensitivity and detection accuracy of the detection element, a plurality of elements (for example, oxygen concentration cell elements, etc.) are stacked, and a heater (for example, a ceramic heater) is provided on both sides of such an element. May be arranged.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a mounting structure of an oxygen sensor 2 according to a first embodiment.

FIG. 2 is an explanatory view showing a mounting structure of an oxygen sensor 40 according to a second embodiment.

[Explanation of symbols]

2, 40: oxygen sensor (gas sensor), 4, 42: metal shell, 8: detecting element, 12: enlarged diameter portion, 100: exhaust pipe,
104, 120: cylindrical part, 104a, 120a: tip opening (mounting hole), 110: notch, 112, 140: elastic member, 122: fixing part, 124: hook part.

Claims (9)

[Claims] An object to be measured is a gas sensor comprising a shaft-shaped detection element having a detection section for detecting a component to be detected in a gas formed at a tip end thereof, and a cylindrical metal shell holding the detection element. A mounting structure of a gas sensor for inserting and fixing in a mounting hole formed in a gas flow pipe so that the detection portion comes into contact with the gas to be formed, and protrudes outward on an outer periphery of the metal shell. The enlarged diameter portion is formed, and the end surface on the distal end side of the enlarged diameter portion is brought into contact with a seat formed on the inner wall of the mounting hole of the gas flow pipe, and the rear end side of the enlarged diameter portion is formed. An attachment structure for a gas sensor, wherein the gas sensor is fixed to the attachment hole via the elastic member by abutting an elastic member partially fixed to the gas flow pipe on an end surface. 2. A cylindrical portion is formed in the gas flow pipe by extending the periphery of the mounting hole outward, and the cylindrical portion is formed on a part of an outer wall of the cylindrical portion. A notch is formed by notching until reaching the inside of the cylinder along a direction orthogonal to the central axis of the cylinder, and the elastic member is inserted into the notch to insert the elastic member into the cylinder. 2. The gas sensor mounting structure according to claim 1, wherein the elastic member is brought into contact with a rear end surface of the enlarged diameter portion of the gas sensor. 3. The gas sensor mounting structure according to claim 2, wherein the notches are provided at two places on an outer wall of the cylindrical portion so as to face each other. 4. A tubular portion is formed in the gas flow pipe by extending the periphery of the mounting hole outward, and an end of the tubular portion opposite to the gas flow pipe. A fixing portion for fixing a part of the elastic member, and a hook for hooking an open end side of the elastic member pulled out from the fixing portion. 1
The mounting structure of the gas sensor according to 1. 5. The elastic member is pulled out of the fixed portion in two directions, and both open end sides of the pulled out elastic member are:
The gas sensor mounting structure according to claim 4, wherein each of the hooks is hooked on the hook. 6. The elastic member is made of a tough rod-shaped metal material, and a portion abutting a rear end side of the enlarged diameter portion is curved so as to press the gas sensor to a front end side. 6. The method according to claim 5, wherein
The mounting structure of the gas sensor according to 1. 7. The elastic member according to claim 1, wherein the elastic member is made of a rod-shaped metal material having toughness, and is formed in an open C-shape. The mounting structure of the gas sensor according to 1. 8. The gas sensor mounting structure according to claim 1, wherein the seat has a tapered shape. 9. The end face on the front end side or the rear end side of the enlarged diameter portion has a tapered shape.
The mounting structure of the gas sensor according to any one of claims 1 to 8.