JP2005134299A - Sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor for retaining a lead wire, even under a high-temperature environment and maintaining airtightness, and has a lead wire retaining member that can be manufactured easily. <P>SOLUTION: An oxygen sensor 1 has a seal unit 10 having an inner retaining member 41 and an outer retaining member 33. An external retaining member 33 can be divided into a tip side formation member 35 and a rear end side formation member 37. With the division structure, the seal unit 10 passes the lead wire to the inner retaining member 41, then arranges the tip side formation member 35 and the rear end side formation member 37 so that the inner retaining member 41 can be pinched, and is formed by retaining the tip side formation member 35 and the rear end side formation member 37 by a member retaining section 63. The manufacturing operation of the seal unit 10 is simpler and can be executed more easily as compared with manufacturing work for filling a rubber material into a narrow through hole, thus reducing complexity in the manufacturing operation of the oxygen sensor 1 (seal unit 10). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention has a cylindrical outer cylinder that houses the rear end portion of the detection element therein, and is connected to the detection element from the outside of the outer cylinder through the rear end side opening of the outer cylinder. And a lead wire holding member that is disposed inside the rear end opening of the outer cylinder and that holds the lead wire in a state of covering the periphery of the lead wire in the radial direction.

  Conventionally, a long detection element that detects a component to be measured, a metal shell that holds the detection element, and a rear end of the detection element that is disposed on the rear end side of the metal shell and is inserted from the front end side opening There is known a sensor including an outer cylinder that accommodates a portion therein.

  Such a sensor includes a lead wire disposed inside the outer cylinder from the outside of the outer cylinder through the rear end opening of the outer cylinder and connected to the detection element, and a rear end opening of the outer cylinder. A lead wire holding member (grommet) that is disposed inside and holds the lead wire in a state of covering the periphery in the radial direction of the lead wire.

  Of these, the grommet is provided to hold the lead wire in the opening at the rear end side of the outer cylinder and to maintain the sealing performance inside the sensor. The grommet is securely attached to the inner surface of the outer cylinder and the outer surface of the lead wire. It is made of a material (rubber or the like) that is easily elastically deformed so as to be able to ensure sealing performance by abutting on the surface.

  However, some sensors are used in a high temperature environment, and rubber has a property of deteriorating when exposed to a high temperature environment for a long time. For this reason, when a sensor used in a high-temperature environment is configured using rubber grommets, the rubber grommets deteriorate due to high temperatures as the sensor usage time elapses, and lead wires can be properly held. Moreover, the problem that sealing performance falls arises.

  On the other hand, in order to improve heat resistance, a grommet main body (lead wire lead-out member 13) including lead wire insertion holes mainly composed of Teflon (registered trademark) is configured, and the lead wire and the lead wire insertion holes A grommet configured by filling a gap with a rubber material (seal rubber 15) has been proposed (see Patent Document 1).

As a result, it is a rubber material that is easily elastically deformed, and can maintain the sealing performance between the lead wire and the grommet body (the inner surface of the lead wire insertion hole), and the heat transferred from the outer cylinder is a material with excellent heat resistance. Therefore, even when used for a long time in a high temperature environment, deterioration due to high temperature can be suppressed.
Japanese Utility Model Publication No. 02-006253 (FIG. 1)

  Incidentally, there is a demand for miniaturization of the sensor, and in order to meet such a demand, the length from the grommet to the rear end portion of the detection element may be shortened as much as possible. However, in this case, since the grommet approaches the detection element, heat from the outer cylinder is easily transmitted to the grommet. Therefore, the rubber grommet used in the conventional sensor is deteriorated, and there is a problem that the lead wire cannot be properly held and the sealing performance is lowered.

  Further, like the grommet provided in the conventional sensor, the grommet having a structure in which the rubber material is filled in the lead wire insertion hole of the grommet main body portion has a gap between the lead wire insertion hole of the grommet main body portion and the lead wire. Since it is narrow, the filling operation of the rubber material becomes complicated.

  For this reason, a sensor including a grommet having a structure in which the lead wire insertion hole of the grommet main body is filled with a rubber material has a problem that the manufacturing process is complicated, the production efficiency is low, and the manufacturing cost is high.

  Therefore, the present invention has been made in view of such problems, and can maintain a lead wire and maintain sealing performance even in a high-temperature environment, and the grommet approaches a detection element in a miniaturized sensor. Another object of the present invention is to provide a sensor including a lead wire holding member (grommet) that can maintain the sealing performance while holding the lead wire and can be easily manufactured.

  The invention according to claim 1, which has been made to achieve such an object, includes a detection element that detects a component to be measured, and a metal shell that holds the detection element so that the axial tip of the detection element is exposed to the object to be measured. An outer cylinder having a substantially cylindrical shape extending in the axial direction, having an opening at the front end and the rear end in the axial direction, arranged on the rear end side of the metal shell, and accommodating the rear end portion of the detection element therein And a lead wire that is disposed from the outside of the outer cylinder to the inside of the outer cylinder through the rear end opening of the outer cylinder, and is disposed inside the rear end opening of the outer cylinder. And a lead wire holding member that holds the lead wire in a state of covering the periphery of the lead wire in the radial direction, the lead wire holding member having a hollow portion for inserting the lead wire. A ring-shaped inner holding member made of A substantially columnar outer holding member made of a heat-resistant material having an inner receiving space for receiving the member, and the outer holding member is held inside the outer cylinder and is internally housed. The inner holding member housed in the inner housing space is in contact with the outer holding member, and the inner diameter dimension of the hollow portion is configured so as to be divided so as to surround the space with a plurality of partial forming members. The sensor is characterized by holding the lead wire by being elastically deformed so as to be reduced.

  In this sensor, a lead wire holding member configured to include an inner holding member and an outer holding member is provided, and in particular, the outer holding member is configured to be divided into a plurality of partial forming members, thereby forming a plurality of partial formations. By combining the members, an internal accommodation space for accommodating the inner holding member is formed.

  The outer holding member configured to be separable in this way is not a single member, and is not a structure in which a through hole for inserting a lead wire is formed in advance, and therefore a thin through hole formed in the outer holding member The filling work of the inner holding member to the inside becomes unnecessary.

  The lead wire holding member is configured so that the outer holding member can be divided. Therefore, after the lead wire is inserted into the inner holding member, a plurality of partial forming members are arranged so as to surround the inner holding member, By forming the outer holding member by combining the partial forming members in the outer cylinder so that the inner housing space is formed by the partial forming member, the lead wire can be held and the rear end opening of the outer cylinder is sealed. Stop property can be secured.

  The sensor manufacturing process including the process of holding the lead wire by the lead wire holding member in this manner is simpler and easier to perform than the manufacturing process of filling the through hole with the rubber material. The complexity of the manufacturing work of the lead wire holding member can be reduced.

  Further, the inner holding member accommodated in the inner accommodating space can reliably hold the lead wire because the inner diameter dimension of the hollow portion is reduced, and there is a gap between the inner holding member and the lead wire. Generation | occurrence | production can be suppressed and the sealing performance between a lead wire and a lead wire holding member can be aimed at.

  Further, since the inner holding member is held by the outer holding member, the outer peripheral surface of the inner holding member abuts on the outer holding member, so that a gap is not generated between the inner holding member and the outer holding member. Further, the sealing performance of the lead wire holding member can be improved. In addition, the elastic force which an inner side holding member generate | occur | produces radially outward also has the effect | action which improves the adhesiveness between an outer side holding member and an outer cylinder.

  In addition, since the outer holding member is formed of a heat resistant material, the lead wire holding member hardly deteriorates due to high temperature even when heat is conducted from the outer cylinder, and is long in a high temperature environment. Can withstand the use of time. Examples of the heat resistant material used for the outer holding member include ceramics (steatite, mullite, alumina) and heat resistant resins (Teflon (registered trademark: PTFE), polyvinyl fluoride (PVF), etc.). I can do it.

  Furthermore, since the lead wire holding member is formed of a heat resistant material, even when the lead wire holding member is arranged at a position close to the detection element as in the case of being provided in a miniaturized sensor, Deterioration is unlikely to occur and the lead wire can be held appropriately. In addition, as a heat resistant material used for an inner side holding member, a metal material, ceramic powder (talc, BN) etc. can be mentioned, for example.

  Therefore, according to the present invention, the lead wire can be held even in a high temperature environment and the sealing performance can be maintained. Even if the grommet approaches the detection element in a miniaturized sensor, the lead wire is held while being held. A sensor having a lead wire holding member (grommet) that can maintain the stop and can be easily manufactured can be realized.

  In the above-described sensor, as described in claim 2, the inner holding member is made of a metal material, and has a shape in which the inner diameter dimension of the hollow portion and the outer diameter dimension thereof change due to elastic deformation. Good.

  As described above, the inner holding member formed of a metal material is unlikely to deteriorate even under a high temperature environment, so that the heat resistance of the lead wire holding member can be improved, and as a result, the heat resistance of the entire sensor can be improved. I can do it.

  The inner holding member formed of a metal material can be configured to be elastically deformable by forming, for example, a bellows shape, and when held by the outer holding member, the inner diameter dimension of the hollow portion is reduced and the inner holding member is reduced. It can be set as the structure which an outer diameter dimension expands. The inner holding member that is elastically deformed in this manner is in a state in which its outer peripheral surface abuts on the outer holding member as its outer diameter increases.

  Next, in the above-described sensor, as described in claim 3, the outer holding member is configured by laminating a plurality of partial forming members in the axial direction, and the plurality of partial forming members penetrates in the axial direction. Each of the lead wire insertion holes may be provided, and an inner housing space may be provided around the opening of the lead wire insertion hole in the contact surface that comes into contact with the other part forming member.

  When the outer holding member having such a configuration is used, the inner holding member is held in a state of being sandwiched by the plurality of partial forming members so that the axial dimension is reduced, and is elasticized by an external force applied from the partial forming member. Deform.

Thereby, the lead wire holding member can hold the lead wire satisfactorily and can maintain the sealing performance in the rear end side opening of the outer cylinder.
In addition, when the outer holding member having such a shape is used, the overall radial dimension of the lead wire holding member can be maintained constant regardless of the relative positional relationship between the plurality of partial forming members. The clearance between the lead wire holding member and the outer cylinder can be set to a constant dimension.

  For this reason, the outer diameter size of the partial forming member is set according to the inner diameter size of the rear end side opening portion of the outer cylinder so that the partial forming member abuts securely on the inner wall surface of the rear end side opening portion of the outer cylinder. Therefore, it is possible to prevent a gap from being formed between the outer peripheral surface of the lead wire holding member and the inner wall surface of the rear end side opening of the outer cylinder, and to improve the sealing performance at the rear end side opening of the outer cylinder. Can be planned.

  Further, in the above-described sensor, as described in claim 4, the outer holding member is constituted by a plurality of partial forming members arranged in the circumferential direction around its own central axis, and the plurality of partial forming members are It is preferable that a lead wire placement groove formed in the axial direction is provided on a contact surface that comes into contact with the other part forming member, and that an inner housing space is provided in an intermediate portion in the axial direction of the lead wire placement groove.

  When the outer holding member having such a configuration is used, the inner holding member is held in a state of being sandwiched by the plurality of partial forming members so that the outer diameter is reduced, and is elastic by an external force applied from the partial forming member. Deform.

Thereby, the lead wire holding member can hold the lead wire satisfactorily and can maintain the sealing performance in the rear end side opening of the outer cylinder.
Further, when the outer holding member having such a shape is used, the outer holding member can be disposed around the lead wire even after the metal terminal member is connected to the end portion of the lead wire so as to surround the lead wire. Since the lead wire holding member can be arranged, there is an advantage that it is possible to cope with various manufacturing processes.

  In addition, when there are a plurality of lead wires, it is desirable that the pressing force applied to each lead wire from the lead wire holding member is uniform, and the lead wire placement groove portion is circumferential in the lead wire holding member. It is good to arrange at equal intervals.

Next, in the above-described sensor, as described in claim 5, the outer holding member may be made of a ceramic material.
Since the outer holding member formed of the ceramic material is less likely to deteriorate even in a high temperature environment, the heat resistance performance of the lead wire holding member can be improved, and as a result, the heat resistance performance of the entire sensor can be improved. it can.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
In the present embodiment, the sensor of the present invention is configured as an oxygen sensor, and FIG. 1 is a cross-sectional view showing the overall configuration of the oxygen sensor. In the present embodiment, in the drawing, the lower end side of the oxygen sensor corresponds to the “front end side of the gas sensor” in the claims, and similarly, the upper end side of the oxygen sensor corresponds to the “rear end side of the gas sensor”.

As shown in the figure, the oxygen sensor 1 is a shaft-shaped element disposed inside the detection element 2 and the detection element 2 formed in a hollow shaft shape whose tip is closed by a solid electrolyte body mainly composed of ZrO ₂ . The ceramic heater 3 includes an internal structure of the oxygen sensor 1 and a casing 4 that fixes the oxygen sensor 1 to a mounting portion such as an exhaust pipe.

  The casing 4 is arranged on the rear end side of the metal shell 5 that holds the detection element 2 and projects the detection part 25 inside the exhaust pipe and the reference gas between the metal shell 5 and the detection element 2. And an outer cylinder 6 forming a space.

  The metal shell 5 has a substantially cylindrical main body, a support member 51 that supports the detection element 2 from below (front end side), and a filling member made of talc powder that fills the upper part (rear end side) of the support member 51. 52 and a sleeve 53 that presses the filling member 52 from above (rear end side) are accommodated inside.

  That is, an inwardly protruding step portion 54 is provided on the inner periphery on the lower end side of the metal shell 5, and the support member 51 is locked to the step portion 54 via the ring 55, thereby detecting the detection element. 2 is supported from below (front end side). A filling member 52 is disposed between the inner peripheral surface of the metal shell 5 and the outer peripheral surface of the detection element 2 on the upper side (rear end side) of the support member 51, and further on the upper side (rear end side) of the filling member 52. ), The upper end (rear end) of the metal shell 5 is crimped inward (downward) in a state where the cylindrical sleeve 53 and the ring 56 are sequentially coaxially inserted. The detection element 2 is firmly fixed to the metal shell 5 by pressure filling.

  And after the front end side opening end part of the outer cylinder 6 is extrapolated by the main body metal fitting 5 so that the rear end side opening part of the metal shell 5 may be covered, welding is given to the front end side opening part of the outer cylinder 6 from the outside. The outer cylinder 6 is attached to the metal shell 5.

  In addition, an insulating separator 7 made of ceramic and formed in a cylindrical shape is disposed inside the outer cylinder 6 on the rear end side of the detection element 2. Specifically, the separator 7 has a flange portion 71 protruding outward on the outer peripheral surface near the center in the axial direction, and is inserted from the rear end side opening portion of the outer cylinder 6, and below the flange portion 71. The end surface is disposed inside the outer cylinder 6 in such a manner that the end surface is locked to the inward projecting portion 69 of the outer cylinder 6.

The inward projecting portion 69 is formed by caulking the rear end portion of the outer cylinder 6 inward from the outer side with respect to the substantially center position in the axial direction.
Further, in the rear end side opening 61 of the outer cylinder 6, lead wires 21 and 22 connected to the electrodes of the detection element 2 and a pair of lead wires connected to the ceramic heater 3 are drawn out to the outside, respectively, and oxygen A seal unit 10 that prevents moisture and oil from entering the sensor 1 and fixes the lead wire is provided.

Further, a metal double protector 81, 82 having a plurality of holes is attached to the outer periphery of the metal shell 5 on the front end side by welding.
Next, the detailed structure of the seal unit 10 which is a main part of the oxygen sensor 1 of the present embodiment will be described with reference to FIG.

  In FIG. 2, an exploded perspective view of the seal unit 10 in a state of being divided into an inner holding member 41 and an outer holding member 33 (front end side forming member 35, rear end side forming member 37) is shown on the upper side in the drawing. A perspective view of the seal unit 10 in an assembled state is shown on the lower side in the drawing. Moreover, in FIG. 2, the internal structure of each member is represented by a dotted line.

  The seal unit 10 has four annular inner holding members 41 having hollow portions 43 through which the lead wires 21, 22 and the like are inserted, and a heat resistance having an inner housing space 34 for housing the inner holding member 41. And a columnar outer holding member 33 made of a material (ceramic).

  The outer holding member 33 is configured to be divided into a columnar front end side forming member 35 and a columnar rear end side forming member 37, and the front end side forming member 35 and the rear end side forming member 37 are arranged in the axial direction. It is configured by stacking.

  The leading end side forming member 35 and the trailing end side forming member 37 are each provided with four lead wire insertion holes 39 penetrating in the axial direction, and the four lead wire inserting holes 39 are formed with the leading end side forming member 35 and The rear end side forming members 37 are provided at equal intervals in the circumferential direction around the central axis. Further, the front-end-side forming member 35 has an internal housing space 34 formed around the opening of the lead wire insertion hole 39 on the contact surface that comes into contact with the rear-end-side forming member 37. An internal housing space 34 is formed around the opening of the lead wire insertion hole 39 in the contact surface that contacts the distal end side forming member 35.

The inner holding member 41 is made of a metal material (stainless alloy) and has a longitudinal cross-sectional shape formed into a bellows shape as can be seen from the cross-sectional shape shown in FIG.
The inner holding member 41 formed of a metal material in this manner is unlikely to deteriorate even in a high temperature environment, so that the heat resistance of the seal unit 10 can be improved, and as a result, the heat resistance of the oxygen sensor 1 can be improved. I can do it.

  Further, since the inner holding member 41 made of a metal material is excellent in heat resistance, the seal unit 10 holds the lead wires 21 and 22 even if the seal unit 10 is disposed at a position close to the detection element 2. However, the sealing property can be maintained.

  Further, the bellows-shaped inner holding member 41 is elastically deformed by applying an external force in a direction in which the axial dimension is shortened, whereby the inner diameter dimension of the hollow portion 43 and its own outer diameter dimension change. When the inner holding member 41 constitutes the seal unit 10 together with the outer holding member 33 (the front end side forming member 35 and the rear end side forming member 37), the inner holding member 41 is arranged between the front end side forming member 35 and the rear end side forming member 37. The external force in the direction in which the axial dimension is shortened is applied.

Next, an operation for arranging the seal unit 10 inside the outer cylinder 6 will be described.
In order to arrange the seal unit 10 inside the outer cylinder 6, first, the leading end side forming member 35 is inserted into the lead wire insertion hole 39 of the leading end side forming member 35 and the leading end side forming member 35 is connected to the rear end face of the separator 7 and the outer cylinder. The tip-end-side forming member 35 is inserted into the outer cylinder 6 until it abuts against the six step portions 66.

  Next, while inserting the lead wire into the hollow portion 43 of the inner holding member 41, remove the inner holding member 41 until the distal end side portion of the inner holding member 41 is accommodated in the inner accommodating space 34 of the distal end side forming member 35. Insert into the tube 6.

  Subsequently, while inserting the lead wire into the lead wire insertion hole 39 of the rear end side forming member 37, the rear end side forming member 37 is removed until the rear end side forming member 37 contacts the rear end surface of the inner holding member 41. Insert into the tube 6.

Thereafter, the member holding portion 63 is formed by crimping the rear end edge inward (downward) of the rear end opening 61 of the outer cylinder 6.
Thereby, the front end surface of the rear end side forming member 37 contacts the rear end surface of the front end side forming member 35, and the seal unit 10 (the front end side forming member 35, the rear end side forming member 37, the inner holding member 41) It is in a state of being sandwiched between the member holding portion 63 of the outer cylinder 6 and the separator 7, and an external force in a direction that shortens the axial dimension is applied.

  As a result, the inner holding member 41 is held by the outer holding member 33 by an external force in the axial direction, is elastically deformed so that the inner diameter dimension of the hollow portion 43 is reduced, and is in contact with the outer periphery of the lead wire without a gap. It becomes. Further, the outer diameter of the inner holding member 41 itself is expanded by elastic deformation, so that the inner wall surface and the inner side of the outer holding member 33 (the front end side forming member 35 and the rear end side forming member 37) that surround the inner housing space 34 are arranged. It will be in the state which contact | abuts with the outer peripheral surface of the holding member 41 without a clearance gap.

  Thus, the seal unit 10 holds the lead wire in the rear end side opening 61 of the outer cylinder 6 and seals the rear end side opening 61 of the outer cylinder 6, thereby sealing the oxygen sensor 1. Can be maintained.

  As described above, the oxygen sensor 1 includes the seal unit 10 that includes the inner holding member 41 and the outer holding member 33, and in particular, the outer holding member 33 includes the front end side forming member 35 and the rear side forming member 35. It is characterized in that the end side forming member 37 can be divided.

  By using the outer holding member 33 configured to be separable in this way, the outer holding member is used as in the case of using an outer holding member made of a single member in which a through hole for inserting a lead wire is formed in advance. The filling work of the inner holding member (rubber material or the like) into the thin through-hole formed in is unnecessary.

  The seal unit 10 is configured such that the outer holding member 33 can be divided. Therefore, after the lead wire is inserted into the inner holding member 41, the front end side forming member 35 and the rear end are sandwiched between the inner holding member 41. The side forming member 37 is arranged, and the front end side forming member 35 and the rear end side forming member 37 are held by the member holding portion 63. The seal unit 10 thus formed can hold the lead wire and can secure the sealing performance of the rear end side opening 61 of the outer cylinder 6.

  The sensor manufacturing operation including the step of holding the lead wire by the seal unit 10 is simpler and easier than the conventional manufacturing operation of filling the through hole of the seal unit (lead wire holding member) with a rubber material. Therefore, the complexity of the manufacturing operation of the seal unit 10 in the manufacturing process of the oxygen sensor 1 can be reduced.

  Further, since the inner holding member 41 is held by the outer holding member 33, the inner diameter dimension of the hollow portion 43 is reduced, so that the lead wire can be reliably held, and the inner holding member 41 and the lead It is possible to improve the sealing performance between the lead wire and the seal unit 10 by suppressing generation of a gap between the lead wire and the seal unit 10.

  Further, since the inner holding member 41 is elastically deformed so as to increase its outer diameter by being held by the outer holding member 33, there is a gap between the inner holding member 41 and the outer holding member 33. It is possible to suppress the occurrence and improve the sealing performance between the lead wire and the seal unit 10. The elastic force generated outwardly in the radial direction by the inner holding member 41 also has an effect of improving the adhesion between the outer holding member 33 and the outer cylinder 6.

  Further, since the outer holding member 33 is formed of a heat-resistant material (ceramic), the seal unit 10 hardly deteriorates due to high temperature even when heat is conducted from the outer cylinder 6, and is a high temperature environment. Can withstand prolonged use underneath. Further, since the inner holding member 41 is formed of a heat resistant material, the seal unit 10 holds the lead wires 21 and 22 even if the seal unit 10 approaches the detection element 2 when the sensor is downsized. However, the sealing property can be maintained. In particular, since the inner holding member 41 is formed of a metal material (stainless alloy) and is not easily deteriorated even in a high temperature environment, the heat resistance of the seal unit 10 can be improved. Improvements can be made.

  Further, since the outer holding member 33 of the seal unit 10 is configured by the front end side forming member 35 and the rear end side forming member 37 stacked in the axial direction, the front end side forming member 35 and the rear end side forming member 37 Regardless of the relative positional relationship, the overall radial dimension of the seal unit 10 can be maintained constant. Therefore, in the oxygen sensor 1, the clearance between the seal unit 10 and the outer cylinder 6 can be set to a constant dimension over the entire circumference in the circumferential direction.

  The front-end-side forming member 35 and the rear-end-side forming member 37 are formed so that the outer diameter dimensions thereof are slightly larger than the inner diameter dimension of the rear-end-side opening 61 of the outer cylinder 6. It is possible to prevent a gap from being formed between the surface and the inner wall surface of the rear end side opening 61 of the outer cylinder 6, and to improve the sealing performance in the rear end side opening 61 of the outer cylinder 6. .

  Therefore, according to the oxygen sensor 1 of the present embodiment, the lead wire can be held even in a high temperature environment and the sealing performance can be maintained, and the lead wire holding member (seal unit) is detected in the downsized sensor. Even when approaching the element, the lead wire holding member can maintain a sealing property while holding the lead wire, and further includes a sensor including a lead wire holding member (seal unit 10) that can be easily manufactured. Can be realized.

  In the oxygen sensor 1, the seal unit 10 corresponds to a lead wire holding member described in the claims, and the front end side forming member 35 and the rear end side forming member 37 correspond to partial forming members.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment (henceforth 1st Embodiment), It can take a various aspect.
For example, the outer holding member 33 is not limited to one made of ceramic, and can be made using other heat resistant materials. Examples of the heat resistant material include Teflon (registered trademark), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (perfluoroalkoxyalkane: PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polychloro Trifluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer (ETFE), chlorotrifluoroethylene / ethylene copolymer (ECTFE), polyvinylidene fluoride (polyvinylidene fluoride: PVDF), polyvinyl fluoride (polyvinylidene) Fluoride: PVF).

  Further, the outer holding member of the seal unit (lead wire holding member) is divided into a plurality of partial forming members (the front end side forming member 35 and the rear end side forming member 37) stacked in the axial direction, like the seal unit 10. The configuration is not limited to the above-described configuration, and may be a configuration that is divided into a plurality of partial forming members that are arranged in the circumferential direction around the center axis of the device itself.

  Therefore, as a second embodiment, FIG. 3 shows a second oxygen sensor 101 including a second outer holding member 133 configured to be divided into a plurality of partial forming members arranged in the circumferential direction around its own central axis. It explains using. FIG. 3 is a cross-sectional view illustrating the entire configuration of the second oxygen sensor 101.

  The second oxygen sensor 101 includes a second seal unit 110 instead of the seal unit 10 in the oxygen sensor 1 of the first embodiment described above, and a caulking portion 163 instead of the member holding portion 63 of the outer cylinder 6. It is configured with. In the figure, components common to the oxygen sensor 1 are denoted by the same reference numerals.

Next, the 2nd seal unit 110 comprised including the 2nd outer side holding member 133 is demonstrated based on FIG.
In FIG. 4, an exploded perspective view of the second seal unit 110 in a state of being divided into an inner holding member 41 and a second outer holding member 133 (four partial forming members 135) is shown on the upper side in the drawing. A perspective view of the assembled second seal unit 110 is shown on the middle and lower side. Moreover, in FIG. 4, the internal structure of each member is represented by the dotted line.

  The second seal unit 110 has four inner holding members 41 having an annular shape having a hollow portion 43 for inserting the lead wires 21, 22 and the like, and an inner receiving space 34 for receiving the inner holding member 41. And a cylindrical second outer holding member 133 made of a heat resistant material (Teflon (registered trademark)).

In addition, the inner side holding member 41 is the structure similar to the inner side holding member 41 with which the seal unit 10 of 1st Example mentioned above is equipped.
The second outer holding member 133 is configured to be separable into four partial forming members 135 arranged in the circumferential direction around the central axis thereof, and the partial forming member 135 has a cross-sectional shape perpendicular to the axial direction. Is formed in a columnar shape having a sector shape (a sector shape having a central angle of 90 °).

  In addition, the partial forming member 135 includes a lead wire arranging groove portion 139 formed in the axial direction on the contact surface 136 that comes into contact with the other partial forming member 135 among its own surface, and the lead wire arranging groove portion 139. Among these, an inner accommodating space groove portion 134 is provided in an intermediate portion in the axial direction.

  When the second outer holding member 133 is formed by combining the partial forming members 135, one lead wire insertion hole 39 is formed by the two lead wire arranging groove portions 139, and two inner housing space groove portions are formed. One internal housing space 34 is formed by 134.

As a result, the second outer holding member 133 is provided with four lead wire insertion holes 39 for inserting lead wires at equal intervals in the circumferential direction in a cross section perpendicular to the axial direction.
Next, an operation for arranging the second seal unit 110 inside the outer cylinder 6 will be described.

  In order to arrange the second seal unit 110 inside the outer cylinder 6, first, the lead wire is inserted into the hollow portion 43 of the inner holding member 41, and the inner holding member 41 is arranged at a predetermined position of the lead wire. Next, four partial forming members 135 are arranged so as to surround a portion of the lead wire where the inner holding member 41 is arranged, and the second outer holding member in a state in which the inner holding member 41 is accommodated therein. 133 is formed, and the second seal unit 110 is configured.

  Subsequently, while changing the relative position between the lead wire and the second seal unit 110, the second seal unit 110 is inserted into the outer cylinder 6, and the second seal unit 110 comes into contact with the rear end surface of the separator 7. The second seal unit 110 is moved inside the outer cylinder 6 to the position.

  Thereafter, a part of the rear end side opening 61 of the outer cylinder 6 is caulked inward in the radial direction to form the caulking part 163, and the four partial forming members 135 are held by the caulking part 163. Thus, the second seal unit 110 (second outer holding member 133, inner holding member 41) is held by the caulking portion 163 of the outer cylinder 6 with a radially inward force.

  As a result, the inner holding member 41 is held by the second outer holding member 133 with a radially inward force, and its outer peripheral surface abuts against the second outer holding member 133 and the inner diameter of the hollow portion 43. The lead wire is held by being elastically deformed so that the size is reduced.

  As a result, the inner holding member 41 is elastically deformed so that the inner diameter dimension of the hollow portion 43 is reduced, and comes into contact with the outer periphery of the lead wire without a gap. Further, the inner holding member 41 is held by the second outer holding member 133 with a radially inward force, so that the inner housing space 34 of the second outer holding member 133 (four partial forming members 135) is surrounded. The inner wall surface and the outer peripheral surface of the inner holding member 41 are in contact with each other without a gap.

  Thus, the second seal unit 110 holds the lead wire in the rear end opening 61 of the outer cylinder 6 and seals the rear end opening 61 of the outer cylinder 6 to seal the oxygen sensor. Sex can be maintained.

  As described above, the oxygen sensor including the second seal unit 110 can hold the lead wire and maintain the sealing performance even in a high temperature environment, like the oxygen sensor 1 of the first embodiment described above. In a miniaturized oxygen sensor, even if the lead wire holding member (second seal unit 110) approaches the detection element, the lead wire holding member can maintain the sealing performance while holding the lead wire. In addition, the sensor includes a lead wire holding member (second seal unit 110) that can be easily manufactured.

The second seal unit 110 corresponds to the lead wire holding member described in the claims.
Here, the measurement result of the test implemented in order to evaluate the heat resistance performance in the seal unit (lead wire holding member) of the oxygen sensor will be described.

  In the measurement test, first, the entire oxygen sensor is accommodated in an electric furnace set at a constant temperature (300 [° C.]) for a fixed time (500 hours), and then the rear end portion of the oxygen sensor (the seal unit 10 is provided). Soak part) in water at room temperature for 1 hour. Thereafter, the oxygen sensor is taken out of the water, wiped off moisture adhering to the surface, and then a test gas having a constant oxygen concentration is supplied to the oxygen sensor, and the output voltage of the oxygen sensor is measured.

  The test gas is a combustion gas of 950 [° C.] obtained by burning propane gas and air with a burner, and the output voltage of the oxygen sensor can be adjusted by adjusting the supply ratio of propane gas and air. It is set to be 900 [mV] or more.

  When the output voltage output from the oxygen sensor indicates an appropriate value (900 [mV] or more) corresponding to the test gas, the oxygen sensor is determined to be normal and is not suitable for the test gas. When an appropriate value (less than 900 [mV]) is indicated, the oxygen sensor is determined to be defective.

  The measurement was conducted using a total of 30 oxygen sensors, 10 oxygen sensors 1 according to an embodiment of the present invention, 10 second oxygen sensors 101, and 10 conventional oxygen sensors. Went. In addition, the conventional oxygen sensor is replaced with the seal unit 10 of the oxygen sensor 1, and the oxygen sensor is configured by using a grommet made of a single member formed entirely of a rubber material (a rubber material that is not a heat-resistant material). It is.

  As a result of the test, the oxygen sensor 1 and the second oxygen sensor 101 are all determined to be normal (10), and two of the conventional oxygen sensors are determined to be normal, 8 Was determined to be defective.

From this, it can be seen that the sensor to which the present invention is applied has excellent heat resistance and can maintain good sealing performance even in applications where it is placed in a high temperature environment.
Next, in the sensor to which the present invention can be applied, the number of lead wires disposed through the rear end opening of the outer cylinder is not limited to four.

Therefore, the third oxygen sensor 201 having a structure in which one lead wire is disposed through the rear end opening of the outer cylinder will be described.
FIG. 5 is a cross-sectional view illustrating the entire configuration of the third oxygen sensor 201.

  The third oxygen sensor 201 includes the third seal unit 210 in place of the seal unit 10 and the third separator 207 in place of the separator 7 in the oxygen sensor 1 of the first embodiment described above. Yes. In the figure, components common to the oxygen sensor 1 are denoted by the same reference numerals.

  The third oxygen sensor 201 is configured by bundling a pair of copper wires connected to the electrodes of the detection element 2 and a pair of copper wires connected to the ceramic heater 3 in an insulated state, respectively. It has.

  The third separator 207 has the same external shape as the separator 7 described above, and includes a flange portion 71. The third separator 207 has an internal structure different from that of the separator 7. The third separator 207 draws four copper wires connected to the detection element 2 and the ceramic heater 3 from the tip side to the inside and is insulated from each other. The multi-core lead wire 221 in which the copper wires are bundled is configured to be led out toward the third seal unit 210 from the rear end side.

Next, the detailed structure of the 3rd seal unit 210 which is the principal part of the 3rd oxygen sensor 201 is demonstrated based on FIG.
In FIG. 6, the third inner state is divided into a third inner holding member 241 and a third outer holding member 233 (a third front end side forming member 235 and a third rear end side forming member 237) on the upper side in the drawing. An exploded perspective view of the seal unit 210 is shown, and a perspective view of the assembled third seal unit 210 is shown on the lower side in the drawing. Moreover, in FIG. 6, the internal structure of each member is represented by a dotted line.

  The third seal unit 210 has an annular third inner holding member 241 having a third hollow portion 243 through which the multicore lead wire 221 is inserted, and a third inner housing for housing the third inner holding member 241. A third outer holding member 233 having a columnar shape made of a heat-resistant material (ceramic) having a space 234.

  The third outer holding member 233 is configured to be divided into a columnar third front end side forming member 235 and a columnar third rear end side forming member 237, and the third front end side forming member 235 and the third rear end forming member 237 are configured to be split. The end-side forming member 237 is configured to be laminated in the axial direction.

  The third front end side forming member 235 and the third rear end side forming member 237 are each provided with a third lead wire insertion hole 239 penetrating in the axial direction, and the third lead wire insertion hole 239 is the third front end. The side forming member 235 and the third rear end side forming member 237 are provided at the central axis portions. The third front end forming member 235 has a third internal housing space 234 formed around the opening of the third lead wire insertion hole 239 on the contact surface that contacts the third rear end forming member 237. In the third rear end side forming member 237, a third internal accommodation space 234 is formed around the opening of the third lead wire insertion hole 239 on the contact surface that comes into contact with the third front end side forming member 235.

  The third inner holding member 241 is made of a metal material (stainless alloy), and is configured such that the radial dimension of the inner holding member 41 in the first embodiment is increased, and the third hollow portion 243 is a multi-core lead wire. It is configured to have a size capable of inserting 221.

  Like the inner holding member 41, the third inner holding member 241 is unlikely to deteriorate even in a high temperature environment, and thus can improve the heat resistance of the third seal unit 210, and as a result, has a heat resistance as the third oxygen sensor 201. Improvements can be made.

  In addition, the bellows-shaped third inner holding member 241 is elastically deformed by applying an external force in a direction in which the axial dimension is shortened, whereby the inner diameter dimension of the third hollow portion 243 and its own outer diameter dimension change. become. The third inner holding member 241 is formed with the third front end side when configuring the third seal unit 210 together with the third outer holding member 233 (the third front end side forming member 235 and the third rear end side forming member 237). By being sandwiched between the member 235 and the third rear end side forming member 237, an external force in a direction in which the axial dimension is shortened is applied.

  In addition, although the operation | work which arrange | positions the 3rd seal unit 210 inside the outer cylinder 6 differs in the number of lead wires compared with the seal unit 10 of 1st Embodiment, the seal unit 10 is arrange | positioned inside the outer cylinder 6. FIG. Since it is substantially the same as the arrangement work, the description is omitted.

  As described above, the third oxygen sensor 201 is the third of the third seal units 210 including the third inner holding member 241 and the third outer holding member 233, similarly to the oxygen sensor 1 of the first embodiment. The outer holding member 233 is characterized in that it can be divided into a third front end side forming member 235 and a third rear end side forming member 237.

  By using the third outer holding member 233 configured to be separable in this way, an outer holding member made of a single member in which a through hole for inserting a lead wire is formed in advance is used. The filling operation of the inner holding member (rubber material or the like) into the thin through hole formed in the holding member becomes unnecessary.

  Since the sensor manufacturing operation including the step of holding the lead wire using the third seal unit 210 is simple and can be easily performed, the manufacturing of the third seal unit 210 in the manufacturing process of the third oxygen sensor 201 is performed. The complexity of work can be reduced.

  Further, the third inner holding member 241 is held by the third outer holding member 233, so that the inner diameter of the third hollow portion 243 is reduced, so that the lead wire can be reliably held. It is possible to improve the sealing performance between the multi-core lead wire 221 and the third seal unit 210 by suppressing the generation of a gap between the third inner holding member 241 and the multi-core lead wire 221. .

  Furthermore, since the third inner holding member 241 is elastically deformed so as to increase its outer diameter by being held by the third outer holding member 233, the third inner holding member 241 and the third outer holding member 241 are held. It is possible to improve the sealing performance between the multi-core lead wire 221 and the third seal unit 210 by suppressing generation of a gap between the member 233 and the member 233. Note that the elastic force generated radially outwardly by the third inner holding member 241 also has an effect of improving the adhesion between the third outer holding member 233 and the outer cylinder 6.

  Therefore, since the third oxygen sensor 201 has the same operational effects as the oxygen sensor 1 of the first embodiment, it can hold the lead wire even in a high temperature environment and can maintain the sealing performance. Becomes a sensor including a simple lead wire holding member (third seal unit 210).

  In the third oxygen sensor 201, the third seal unit 210 corresponds to the lead wire holding member recited in the claims, and the third front end side forming member 235 and the third rear end side forming member 237 are partially formed. It corresponds to a member.

  Next, as a fourth embodiment, a first lead wire is provided, and a fourth outer holding member 333 configured to be divided into a plurality of partial forming members arranged in the circumferential direction about its own central axis is provided. The 4-oxygen sensor 301 will be described with reference to FIG. FIG. 7 is a cross-sectional view illustrating the overall configuration of the fourth oxygen sensor 301.

  The fourth oxygen sensor 301 includes a fourth seal unit 310 instead of the third seal unit 210 in the third oxygen sensor 201 of the third embodiment described above, and replaces the member holding portion 63 of the outer cylinder 6. A caulking portion 163 is provided. In the figure, components common to the third oxygen sensor 201 are denoted by the same reference numerals.

Next, the 4th seal unit 310 comprised including the 4th outer side holding member 333 is demonstrated based on FIG.
In FIG. 8, an exploded perspective view of the fourth seal unit 310 in a state divided into a third inner holding member 241 and a fourth outer holding member 333 (four fourth part forming members 335) is shown on the upper side in the drawing. In addition, a perspective view of the assembled fourth seal unit 310 is shown on the lower side in the drawing. Moreover, in FIG. 8, the internal structure of each member is represented by the dotted line.

  The fourth seal unit 310 has an annular third inner holding member 241 having a third hollow portion 243 for inserting the multicore lead wire 221 and a third inner housing for housing the third inner holding member 241. And a fourth outer holding member 333 having a columnar shape made of a heat-resistant material (Teflon (registered trademark)) having a space 234.

In addition, the 3rd inner side holding member 241 is the structure similar to the 3rd inner side holding member 241 with which the 3rd seal unit 210 of the 3rd Example mentioned above is equipped.
The fourth outer holding member 333 is configured to be separable into four fourth part forming members 335 arranged in the circumferential direction around the center axis thereof, and the fourth part forming member 335 is formed in the axial direction. A vertical cross-sectional shape is formed in a columnar shape having a sector shape (a sector shape having a central angle of 90 °).

  In addition, the fourth part forming member 335 includes a fourth lead wire arrangement groove 339 formed in the axial direction on the contact surface 336 in contact with the other fourth part forming member 335 of its own surface, A fourth internal housing space groove 334 is provided in an intermediate portion in the axial direction of the fourth lead wire arranging groove 339.

  When the fourth part forming members 335 are combined to form the fourth outer holding member 333, one third lead wire insertion hole 239 is formed by the two fourth lead wire arranging grooves 339, and 2 One fourth internal storage space 234 is formed by the four fourth internal storage space grooves 334.

  As a result, the fourth outer holding member 333 is configured to include a third lead wire insertion hole 239 for inserting the multicore lead wire 221 in a central axis portion in a cross section perpendicular to the axial direction.

  In addition, although the number of lead wires differs in the operation | work which arrange | positions the 4th seal unit 310 inside the outer cylinder 6 compared with the 2nd seal unit 110 of 2nd Embodiment, the 2nd seal unit 110 is used for the outer cylinder 6 The description is omitted because it is substantially the same as the arrangement work to be arranged in the interior.

  By performing the same operation as the second seal unit 110, the fourth seal unit 310 is held by the crimping portion 163 in the rear end side opening 61 of the outer cylinder 6. Thus, the fourth seal unit 310 holds the multi-core lead wire 221 in the rear end side opening 61 of the outer cylinder 6 and seals the rear end side opening 61 of the outer cylinder 6 to thereby provide an oxygen sensor. The sealing property of can be maintained.

  As described above, the fourth oxygen sensor 301 including the fourth seal unit 310 can hold the lead wire and maintain the sealing performance even in a high temperature environment, like the oxygen sensor 1 of the first embodiment described above. Thus, the sensor includes a lead wire holding member (fourth seal unit 310) that can be easily manufactured.

The fourth seal unit 310 corresponds to the lead wire holding member described in the claims.
In the above, the present invention has been described according to the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment. However, the present invention is not limited to the above embodiment, and the gist thereof is described. Needless to say, the present invention can be changed and applied as appropriate without departing from the scope of the invention.

  For example, in the oxygen sensor 1 of the first embodiment, the rear end surface of the front end side forming member 35 and the front end surface of the rear end side forming member 37 are each formed in a flat surface, and are configured to contact each other on this flat surface. However, it is not limited to such a configuration. For example, as shown in FIG. 9, a convex portion 45 is formed on the front end side forming member 35, a concave portion 47 is formed on the rear end side forming member 37, and the front end is formed in a state where the convex portion 45 and the concave portion 47 are fitted. You may comprise so that the side formation member 35 and the rear-end side formation member 37 may contact | abut. Thereby, it becomes easy to match the relative positions of the front end side forming member 35 and the rear end side forming member 37.

  In addition, the formation position of the convex part and the recessed part in the front end side forming member 35 and the rear end side forming member 37 is not limited to the above-described form. A convex portion may be formed on 37. Furthermore, the form provided with the convex part and the concave part can also be applied to the second embodiment, the third embodiment, and the fourth embodiment.

  Further, in the oxygen sensor 1 of the first embodiment and the third oxygen sensor 201 of the third embodiment, the member holding portion 63, the seal unit 10 and the third seal unit 210 are in direct contact with each other. However, the present invention is not limited to this, and it may be configured to abut via the plate packing 64 or the wire packing 65 as shown in FIGS. Thereby, sealing performance can be improved.

  Further, the seal unit 10 of the first embodiment is in contact with the rear end surface of the separator 7 and the stepped portion 66 of the outer cylinder 6, but is not limited to this, and only the separator 7 as shown in FIG. You may contact | abut. Further, as shown in FIG. 11, only the stepped portion 66 of the outer cylinder 6 may be contacted.

  The seal unit 10 shown in FIG. 11 includes a talc inner holding member 42 made of talc instead of the inner holding member 41 made of a metal material (stainless alloy) in the first embodiment. In the case of using the talc inner holding member 42, the inner holding space 42 of the outer holding member 33 can be filled with the talc inner holding member 42 without any gap, so that the sealing performance of the seal unit can be improved. it can.

It is sectional drawing showing the whole structure of an oxygen sensor. The upper side in the figure is an exploded perspective view of the seal unit divided into an inner holding member and an outer holding member (front end side forming member, rear end side forming member), and the lower side in the figure is an assembled state. It is a perspective view of a seal unit. It is sectional drawing showing the whole structure of a 2nd oxygen sensor. The upper side in the figure is an exploded perspective view of the second seal unit divided into an inner holding member and a second outer holding member (four partial forming members), and the lower side in the figure is an assembled state. It is a perspective view of a 2nd seal unit. Sectional drawing showing the whole structure of a 3rd oxygen sensor is shown. The upper side in the drawing is an exploded perspective view of the third seal unit in a state of being divided into a third inner holding member and a third outer holding member (third front end side forming member, third rear end side forming member). The middle lower side is a perspective view of the third seal unit in an assembled state. It is sectional drawing showing the whole structure of a 4th oxygen sensor. The upper side in the drawing is an exploded perspective view of the fourth seal unit in a state of being divided into a third inner holding member and a fourth outer holding member (four fourth part forming members), and the lower side in the drawing is an assembly. It is a perspective view of the 4th seal unit in the state where it was done. It is a perspective view of a seal unit provided with the front end side forming member in which the convex part was formed, and the rear end side forming member in which the recessed part was formed. It is sectional drawing of the rear-end part of the sensor comprised so that a member holding | maintenance part and a seal unit may contact | abut via plate packing. It is sectional drawing of the rear-end part of a sensor comprised so that a member holding | maintenance part and a seal unit may contact | abut via wire packing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Oxygen sensor, 2 ... Detection element, 3 ... Ceramic heater, 5 ... Main metal fitting, 6 ... Outer cylinder, 10 ... Seal unit, 21, 22 ... Lead wire, 33 ... Outer holding member, 34 ... Internal accommodation space, 35 ... front end side forming member, 37 ... rear end side forming member, 39 ... lead wire insertion hole, 41 ... inner holding member, 43 ... hollow part, 61 ... rear end side opening part, 63 ... member holding part, 101 ... second 110 ... second seal unit, 133 ... second outer holding member, 135 ... partial forming member, 163 ... caulking portion, 201 ... third oxygen sensor, 210 ... third seal unit, 221 ... multi-core lead wire 233 ... third outer holding member, 234 ... third inner housing space, 235 ... third front end side forming member, 237 ... third rear end side forming member, 239 ... third lead wire insertion hole, 241 ... third inner side Holding member, 243 ... 3rd inside Department, 301 ... fourth oxygen sensor, 310 ... fourth sealing unit, 333 ... fourth outer retaining member, 335 ... fourth portion forming member.

Claims (5)

A detection element for detecting a component to be measured;
A metal shell for holding the detection element so as to expose the tip of the detection element in the axial direction to the object to be measured;
It has a substantially cylindrical shape extending in the axial direction, is formed with an opening at the front end and the rear end in the axial direction, and is disposed on the rear end side of the metal shell and accommodates the rear end portion of the detection element inside A tube,
A lead wire disposed inside the outer cylinder from the outside of the outer cylinder through the rear end side opening of the outer cylinder, and connected to the detection element;
A lead wire holding member that is disposed inside the rear end side opening of the outer cylinder and that holds the lead wire in a state of covering the radial periphery of the lead wire;
A sensor comprising:
The lead wire holding member is
An annular inner holding member made of a heat-resistant material having a hollow portion for inserting the lead wire,
A substantially columnar outer holding member made of a heat-resistant material having an inner receiving space for receiving the inner holding member, and
The outer holding member is configured to be separable so as to be held inside the outer cylinder and to surround the inner housing space by a plurality of partial forming members,
The inner holding member housed in the inner housing space holds the lead wire by elastically deforming so that the outer peripheral surface of the inner holding member abuts on the outer holding member and the inner diameter of the hollow portion is reduced. about,
Sensor characterized by. The inner holding member is made of a metal material and has a shape in which the inner diameter dimension of the hollow portion and the outer diameter dimension of the hollow portion change due to elastic deformation,
The sensor according to claim 1. The outer holding member is configured by laminating the plurality of partial forming members in the axial direction,
Each of the plurality of partial forming members includes a lead wire insertion hole penetrating in the axial direction, and the inner accommodating space is formed around an opening of the lead wire insertion hole in a contact surface that comes into contact with another partial formation member. Preparing,
The sensor according to claim 1 or 2, wherein The outer holding member is constituted by the plurality of part forming members arranged over the circumferential direction around its own central axis,
The plurality of partial forming members include a lead wire arranging groove portion formed in an axial direction on an abutting surface that comes into contact with another partial forming member, and the lead wire arranging groove portion includes an intermediate portion in the axial direction of the lead wire arranging groove portion. Providing an internal housing space,
The sensor according to claim 1 or 2, wherein The outer holding member is formed of a ceramic material;
The sensor according to any one of claims 1 to 4, wherein:

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