JP6255307B2 - Sensor - Google Patents

Description

  The present invention includes a detection element extending in the axial direction, an enclosing member that surrounds the rear end of the detection element, a plurality of terminal members that are electrically connected to the detection element, and the terminal members are insulated from each other. The present invention relates to a sensor including an insulating separator that is held while holding a holding metal fitting that holds the insulating separator on a surrounding member.

Conventionally, as a sensor such as a gas sensor such as an oxygen sensor, a NOx sensor, and a CO ₂ sensor, or a temperature sensor, a sensor constituted by a detection element, a surrounding member, a plurality of terminal members, an insulating separator, a holding bracket, and the like has been known. Yes. Specifically, the detection element has a form extending in the axial direction, and a plurality of electrode pads are formed at the rear end of the element. The surrounding member is, for example, a cylindrical metal member, and surrounds the element rear end portion of the detection element from the outside in the radial direction. Each terminal member is electrically connected to the electrode pad of the detection element. The holding metal fitting is disposed between the surrounding member and the insulating separator, and holds the insulating separator on the surrounding member.

  The insulating separator is made of insulating ceramic, and is disposed in the surrounding member, and each terminal member is housed and held in its internal housing hole in a state of being insulated from each other. Thereby, the terminal members are electrically insulated from each other, and the terminal members, the holding metal fittings, and the surrounding member in contact with the terminal members are also electrically insulated. As this insulating separator, for example, an insulating separator configured by combining two separators, such as a combination of a leading end side separator positioned on the leading end side and a trailing end side separator positioned further on the rear end side. There is. This type of sensor is described in, for example, Patent Document 1 (see FIG. 1 of Patent Document 1 and its explanation).

  By the way, since the atmosphere in the surrounding member normally contains moisture, condensation may occur on the surface of the insulating separator depending on the external temperature. When condensation occurs, the insulating properties of the surface of the insulating separator are reduced. For this reason, a leakage current may flow between the terminal members accommodated in the insulating separator, or a leakage current may flow between the terminal member, the holding metal fitting, and the surrounding member in contact therewith. As a result, a normal output may not be obtained from the detection element.

  In order to solve this problem, in the sensor described in Patent Document 1, a coating layer (water repellent layer) having water repellency is formed on the entire surface of the insulating separator. By providing the water repellent layer in this way, water hardly adheres to the surface of the insulating separator even if dew condensation occurs in the surrounding member. Therefore, it can prevent that the insulation of the surface of an insulating separator falls, and can ensure the insulation between terminal members and the insulation between a terminal member, a holding metal fitting, and an enclosing member.

Japanese Patent No. 5179545

  However, when the water repellent layer is provided on the entire surface of the insulating separator, the holding metal fitting that holds the insulating separator on the surrounding member grips the insulating separator through the water repellent layer. For this reason, when a strong impact is applied to the sensor from the outside, the holding separator may not be able to reliably hold the insulating separator, for example, the insulating separator is easily detached from the holding bracket.

  This invention is made | formed in view of this present condition, Comprising: The insulation between the terminal members accommodated in the insulating separator comprised combining the 1st separator and the 2nd separator, and a terminal member, It is an object of the present invention to provide a sensor that can prevent a decrease in insulation between the holding metal fitting and the surrounding member and that can reliably hold an insulating separator.

  One aspect of the present invention for solving the above-described problems is a detection element having a configuration extending in the axial direction, and having a plurality of electrode pads at the element rear end on the rear end side in the axial direction, and the detection element A metal surrounding member that surrounds the rear end of the element from the outside in the radial direction perpendicular to the axial direction, a plurality of terminal members that are electrically connected to the plurality of electrode pads of the detection element, respectively, and insulation An insulating separator made of ceramic, disposed in the surrounding member, and holding the plurality of terminal members in their internal housing holes while insulating the terminal members from each other, interposed between the surrounding member and the insulating separator, A holding metal fitting that grips the insulating separator from outside in the radial direction and holds the insulating member on the surrounding member, wherein the insulating separator includes a first separator that divides the internal accommodation hole; A first surface that is a surface of the first separator, and a second surface that is a surface of the second separator. A water repellent layer having water repellency is formed on a second combination surface to be combined with the first separator, and the holding metal fitting is in contact with and grips the first surface and the second surface. On the surface to be gripped, the holding metal fitting is in direct contact with the water repellent layer without being formed.

In the case where the insulating separator is composed of two members, water generated by dew condensation accumulates particularly in a portion (between combined surfaces) where one separator (first separator) and the other separator (second separator) are combined. easy. Even when the temperature rises and the water on the surface of other parts evaporates, water tends to remain in this part. And the fall of the insulation between terminal members and the fall of the insulation between a terminal member, a holding metal fitting, and an enclosing member mainly originate in the water collected between these combination surfaces.
Therefore, in this sensor, a water repellent layer is provided on at least the first combination surface of the first surface of the first separator and on at least the second combination surface of the second surface of the second separator. Thereby, even when dew condensation occurs in the surrounding member, it is difficult for water to collect in a portion (between the first combination surface and the second combination surface) of the insulating separator in which the first separator and the second separator are combined. Become. Therefore, due to the water adhering to this part, the insulation between the terminal members accommodated in the insulating separator and the insulation between the terminal member and the holding metal fitting and the surrounding member are reduced. Can be prevented.
In addition, in this sensor, a water repellent layer is not formed on the surface to be gripped of the first surface and the second surface, which is held by the holding fixture, and the surface of the insulating separator (the surface to be gripped) is not formed. The holding bracket is in direct contact. Therefore, the holding bracket can securely hold the insulating separator.

  The “first combined surface” means the second surface of the second separator (specifically, when the insulating separator is configured by combining the first separator and the second separator among the first surfaces of the first separator. Is a surface in contact with the second combination surface. Similarly, the “second combination surface” refers to the first surface of the first separator (specifically, when the insulating separator is configured by combining the first separator and the second separator among the second surfaces of the second separator. Specifically, it is a surface that comes into contact with the first combination surface.

Examples of the “sensor” include an oxygen sensor, a NOx sensor, a gas sensor such as a CO ₂ sensor, a temperature sensor, and the like.
As the “insulating separator”, for example, the one divided into two on the front end side and the rear end side in the axial direction, that is, the insulating separator is a front end side separator (first separator) located on the front end side, and the rear end side The form comprised combining the rear end side separator (2nd separator) located in is mentioned. Moreover, the insulation separator which consists of a 1st separator and a 2nd separator which were divided into 2 vertically along the axial direction is also mentioned.
Examples of the “water-repellent layer” include a water-repellent layer made of a fluororesin compound such as Teflon (registered trademark) and a water-repellent layer made of an inorganic ceramic material having water repellency.

  Furthermore, in the above sensor, the first surface and the second surface may include a part of the internal accommodation hole from the first combination surface, following the first combination surface of the first surface. Of the second surface, the first opening adjacent surface extending to the first opening edge in which the first housing hole is formed, and the second surface of the second combination surface. At least one of the second opening adjacent surfaces extending to the second opening edge where the second accommodation hole forming a part of the first opening hole is open, and the first opening adjacent surface and the second opening adjacent surface Of these, a sensor in which the water-repellent layer is also formed on the existing surface is preferable.

  The insulating separator according to this sensor has at least one of the first opening adjacent surface and the second opening adjacent surface on the first surface and the second surface. Further, in addition to the first combination surface and the second combination surface, a water repellent layer is also provided on a surface existing among the first opening adjacent surface and the second opening adjacent surface. This makes it difficult for water to adhere to the first combination surface and the second combination surface, and also makes it difficult for water to adhere to the first opening adjacent surface and the second opening adjacent surface following these combination surfaces. . Thereby, the fall of the insulation between terminal members and the insulation between a terminal member, a holding metal fitting, and an enclosing member can be prevented further appropriately.

  In the first separator in which the first combination surface extends to the first opening edge where the first accommodation hole opens, the first opening adjacent surface does not exist on the first surface, but the first combination surface In the first separator that does not extend to the first opening edge, the first opening adjacent surface exists between the first combination surface and the first opening edge. Similarly, in the second separator in which the second combination surface extends to the second opening edge where the second accommodation hole opens, the second opening adjacent surface does not exist on the second surface, but the second combination In the second separator in which the surface does not extend to the second opening edge, the second opening adjacent surface exists between the second combination surface and the second opening edge.

  In addition, “a water repellent layer is also formed on the surface existing between the first opening adjacent surface and the second opening adjacent surface” means that the first opening adjacent surface and the second opening adjacent surface are Among these, when only the first opening adjacent surface exists, a water repellent layer is formed on the first opening adjacent surface, and the second opening of the first opening adjacent surface and the second opening adjacent surface is formed. When only the adjacent surface is present, a water repellent layer is formed on the second opening adjacent surface, and when both the first opening adjacent surface and the second opening adjacent surface are present, the first It means that a water repellent layer is formed on each of the opening adjacent surface and the second opening adjacent surface.

  Furthermore, in the sensor according to any one of the above, the first separator is a front end side separator, and the second separator is a rear end side positioned on the rear end side in the axial direction of the front end side separator. The first surface and the second surface of the first surface, the first rear surface facing the rear end side in the axial direction, following the first combination surface, and In addition, there is at least one of the second surfaces facing the second combination surface and facing the distal end side in the axial direction among the second surfaces, and these first rear end facing surfaces and A sensor in which the water-repellent layer is also formed on a surface existing among the surfaces facing the second tip is preferable.

The insulating separator according to this sensor has at least one of the first rear end facing surface and the second front end facing surface on the first surface and the second surface. Further, in addition to the first combination surface and the second combination surface, a water repellent layer is also provided on the existing surface of the first rear end surface and the second front end surface. This makes it difficult for water to adhere to the first combination surface and the second combination surface, and also makes it difficult for water to adhere to the first rear-facing surface and the second front-facing surface following these combination surfaces. Thereby, the fall of the insulation between terminal members and the insulation between a terminal member, a holding metal fitting, and an enclosing member can be prevented further appropriately.
The “first rear end facing surface” may also correspond to the “first opening adjacent surface” described above. The “second tip-facing surface” may also correspond to the “second opening adjacent surface” described above.

It is a longitudinal section of the gas sensor concerning an embodiment. It is the expansion longitudinal cross-sectional view which expanded the site | part of the insulating separator vicinity among the gas sensors which concern on embodiment. It is the expanded longitudinal cross-sectional view which expanded the site | part of the combination part vicinity of the front end side separator and the rear end side separator among the gas sensors which concern on embodiment. It is a graph which shows the insulation between the terminal members before and behind an insulation test about an Example. It is a graph which shows the insulation between the terminal members before and behind an insulation test about the comparative example 1. FIG. It is a graph which shows the insulation between the terminal members before and behind an insulation test about the comparative example 2. FIG. It is a graph which shows the insulation between the terminal members before and after an insulation test about the comparative example 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a gas sensor (sensor) 1 according to the present embodiment. 1 to 3, the direction along the axis AX of the gas sensor 1 and its detection element 40 is defined as an axial direction HJ, and the side where the detection unit 41 d of the detection element 40 is arranged in the axial direction HJ (lower in the figure) Side) is the front end side GS, and the opposite side (upper side in the figure) is the rear end side GK. This gas sensor 1 is a NOx sensor, is attached to an exhaust pipe (not shown) of an automobile, and the detection part 41d of the detection element 40 is exposed to the exhaust gas flowing through the exhaust pipe, and NOx contained in the exhaust gas. The concentration of is detected. The gas sensor 1 includes a metal shell 10, a protector 20, an enclosing member 30, a detection element 40, an insulating separator 50, a terminal member 60, a holding metal 90, and the like.

Among these, the metal shell 10 is a cylindrical metal member (specifically, carbon steel) having a shaft hole 10h penetrating in the axial direction HJ. A protector 20 (to be described later) is attached to the metal tip part 11 located on the tip side GS of the metal shell 10. On the other hand, a surrounding member 30 described later is attached to the metal fitting rear end portion 12 located on the rear end side GK of the metal shell 10.
The protector 20 is a metal member having a double structure that surrounds the periphery of an element tip 41 of the detection element 40 to be described later and protects the detection element 40 from moisture and physical impact. The protector 20 is joined (specifically, welded) to the metal tip 11 while being externally fitted to the metal tip 11 of the metal shell 10.

  Next, the surrounding member 30 will be described. The surrounding member 30 is a cylindrical metal member (specifically, SUS member) extending in the axial direction HJ. The front end portion 31 of the surrounding member 30 is joined (specifically, welded) to the metal shell 10 in a state of being fitted around the metal rear end portion 12 of the metal shell 10. On the other hand, the rear end portion 33 of the surrounding member 30 is loaded with an elastic member 39 made of fluorine rubber. The rear end portion 33 is crimped radially inward, whereby the elastic member 39 is fixed to the surrounding member 30 and the inside of the surrounding member 30 is hermetically sealed. The elastic member 39 is formed with six insertion holes 39h (two of which are shown in FIG. 1) penetrating in the axial direction HJ. Each insertion hole 39h has a terminal member 60 described later. Lead wires 65 to be connected are respectively inserted. Further, a portion of the surrounding member 30 that is located in the center in the axial direction HJ is a crimped portion 32 that is crimped radially inward to reduce the diameter, and a holding metal fitting 90 that will be described later is directed radially inward. Press.

  Next, the detection element 40 will be described. The detection element 40 has a form extending in the axial direction HJ, specifically, an elongated plate shape extending in the axial direction HJ. In FIGS. 1 and 2, the detection element 40 is shown with the left-right direction of the paper as the plate thickness direction and the front-back direction of the paper as the plate width direction. The detection element 40 is held by the metal shell 10. Specifically, the element front end portion 41 located on the front end side GS protrudes to the front end side GS from the metal shell 10, and the element rear end portion 43 located on the rear end side GK is closer to the rear end side GK than the metal shell 10 The element body 42 that protrudes and is located between the element front end portion 41 and the element rear end portion 43 is held by the metal shell 10 in a state of being disposed in the shaft hole 10 h of the metal shell 10.

  This detection element 40 is formed by laminating and integrating a gas detection body and a heater body (not shown). The gas detector includes a first oxygen pump cell and a second oxygen pump cell in which a pair of electrodes are formed on a solid electrolyte body mainly composed of zirconia, and detects the NOx concentration. On the other hand, the heater body performs heating in order to activate the gas detection body early. In the detection element 40, the element tip 41 is provided with a detection part 41d for detecting the concentration of NOx. On the other hand, a total of six electrode pads 47 (two of which are shown in FIGS. 1 and 2) are formed on the element rear end 43 of the detection element 40, three on each side.

  Next, the insulating separator 50 will be described. The insulating separator 50 is made of insulating ceramic (specifically, alumina), is disposed in the surrounding member 30, and is connected to the element rear end 43 and the lead wire 65 of the detection element 40 in its internal housing hole 50 h. Six terminal members 60 (two of which are mainly shown in FIGS. 1 and 2) are accommodated. The insulating separator 50 holds the terminal members 60 while being insulated from each other in a non-contact state to ensure electrical insulation between the terminal members 60 and the terminal member 60 and a holding metal fitting 90 to be described later and the same. The electrical insulation between the surrounding member 30 and the surrounding member 30 is ensured.

  This insulating separator 50 includes a front end side separator (first separator) 51 located on the front end side GS and a rear end side separator (second separator) used in combination with the front end side separator 51 located further on the rear end side GK. ) 55. Further, the internal accommodation hole 50h of the insulating separator 50 includes a front end side accommodation hole (first accommodation hole) 51h formed in the front end side separator 51 and a rear end side formed in the rear end side separator 55, as will be described later. It is comprised by the accommodation hole (2nd accommodation hole) 55h.

  The front end side separator 51 has a cylindrical main body 52 having a front end side receiving hole 51h that penetrates the front end side separator 51 in the axial direction HJ, and a flange protruding from the main body portion 52 to the radially outer side and the rear end side GK. Part 53. The tip-side accommodation hole 51h faces six recesses that face the inside of the tip-side accommodation hole 51h, side by side. In the front end side receiving hole 51h, the front end side contact portions 61 of the six terminal members 60 are insulated from each other by being spaced apart from each other in the above-described recesses. An element rear end 43 of the detection element 40 is disposed inside. And in this front end side accommodation hole 51h, the front end side contact part 61 of each terminal member 60 and the six electrode pads 47 of the element rear end part 43 are in contact with each other and are conducted.

  On the other hand, the rear end side separator 55 is fitted to the front end side separator 51 in a state of being in contact with the main body portion 52 and the flange portion 53 on the radially inner side of the flange portion 53 of the front end side separator 51. The rear end side separator 55 is formed with six rear end side accommodation holes 55h penetrating in the axial direction HJ. Each of these rear end side accommodation holes 55h has a cylindrical shape. The rear end side holding portions 62 of the six terminal members 60 are inserted into the respective rear end side accommodation holes 55h. The rear end side gripping portions 62 grip the lead wires 65 (core wires thereof) in the rear end side accommodation holes 55h. Each lead wire 65 extends to the rear end side GK from the rear end side separator 55, passes through the insertion hole 39 h of the elastic member 39, and is drawn out of the gas sensor 1.

  The front surface side (first surface) 51c of the front end side separator 51 of the present embodiment includes a front end surface 52s, a rear end surface 52k, an inner peripheral surface 52n and an outer peripheral surface 52m of the main body 52, and a front end side tapered surface 53s of the flange portion 53. It consists of a rear end face 53k, an inner peripheral face 53n, and an outer peripheral face 53m. Specifically, the front end surface 52s of the main body portion 52 is a surface that is located at the front end of the main body portion 52 and faces the front end side GS. The rear end surface 52k of the main body portion 52 is a surface that is located at the rear end of the main body portion 52 and faces the rear end side GK. The inner peripheral surface 52n of the main body 52 is a surface that is located inside the main body 52 and connects the front end surface 52s and the rear end surface 52k of the main body 52. The inner peripheral surface 52n accommodates the front end side. A hole 51h is formed. The outer peripheral surface 52 m of the main body 52 is a cylindrical surface that forms the outer periphery of the main body 52, and connects the front end surface 52 s of the main body 52 and the front end tapered surface 53 s of the flange 53.

  Further, the distal end side tapered surface 53s of the flange portion 53 is a surface that is located on the distal end side GS of the flange portion 53 and has a truncated cone shape, and as described above, the rear surface 52m of the main body portion 52 is rearward. It is connected to the end side GK. The rear end surface 53k of the collar portion 53 is a surface having an annular shape that is located at the rear end of the collar portion 53 and faces the rear end side GK. Further, the inner peripheral surface 53n of the flange portion 53 is a cylindrical surface that forms the inner periphery of the flange portion 53, and connects the rear end surface 52k of the main body portion 52 and the rear end surface 53k of the flange portion 53. . Further, the outer peripheral surface 53m of the flange portion 53 is a cylindrical surface that forms the outer periphery of the flange portion 53, and connects the front end side tapered surface 53s of the flange portion 53 and the rear end surface 53k.

  Of these, the rear end surface 52k of the main body 52 abuts against the rear end separator 55 (specifically, abuts against an opposite surface 55sa of a front end surface 55s of the rear end separator 55 described later). It is divided into a facing surface 52ka and a non-facing surface 52kb that does not face the rear end side separator 55. The inner peripheral surface 53 n of the flange portion 53 is a contact surface that contacts the rear end side separator 55. Of the surface 51c of the front end side separator 51, the opposing surface 52ka of the rear end surface 52k of the main body portion 52 and the inner peripheral surface 53n of the flange portion 53 correspond to the aforementioned “first combination surface”.

  Further, the non-facing surface 52kb of the rear end surface 52k of the main body 52 is continued from the facing surface 52ka of the rear end surface 52k, and from this facing surface 52ka, a front end side accommodation hole 51h that forms a part of the front end side GS of the internal accommodation hole 50h. It is a surface extending to the opening edge (first opening edge) 52 kf that opens, and corresponds to the aforementioned “first opening adjacent surface”. The non-facing surface 52 kb is a surface that follows the facing surface 52 ka of the rear end surface 52 k and faces the rear end side GK, and therefore corresponds to the above-described “first rear end facing surface”. Further, the rear end surface 53k of the flange portion 53 is a surface that continues to the inner peripheral surface 53n of the flange portion 53 and faces the rear end side GK, and the rear end surface 53k is also the above-mentioned “first rear end facing surface”. Equivalent to.

  A first water repellent layer having water repellency is provided on the opposing surface 52ka of the rear end surface 52k of the main body 52, which is the “first combination surface”, and the inner peripheral surface 53n of the flange portion 53 of the surface 51c of the front end side separator 51. 54 is formed. The first water repellent layer 54 is a layer having a thickness of about 1 μm formed from an inorganic ceramic material having water repellency. In the present embodiment, in addition to this, of the surface 51c of the front end side separator 51, the non-opposing surface of the rear end surface 52k of the main body 52 that is the “first opening adjacent surface” and the “first rear end facing surface”. The first water repellent layer 54 is also formed on the rear end surface 53k of the flange portion 53 that is 52 kb and the “first rear end facing surface”. Accordingly, the first water repellent layer 54 is formed on the entire rear end surface 52k of the main body 52.

  The first water repellent layer 54 is formed as follows. That is, masking is performed on the entire surface of the rear end surface 52k of the main body 52 and the surfaces other than the rear end surface 53k and the inner peripheral surface 53n of the flange portion 53 in the surface 51c of the front end side separator 51. Then, a coating agent containing an inorganic ceramic material having water repellency is applied to the entire rear end surface 52k of the main body 52, and the rear end surface 53k and the inner peripheral surface 53n of the flange portion 53, and dried to form a first repellent. An aqueous layer 54 is formed. Then remove the masking.

  On the other hand, of the surface 51c of the front end side separator 51, surfaces other than the rear end surface 52k of the main body portion 52 and the rear end surface 53k and inner peripheral surface 53n of the flange portion 53, that is, the front end surface 52s and inner peripheral surface 52n of the main body portion 52. Further, the water repellent layer is not formed on the outer peripheral surface 52m, and the tip side tapered surface 53s and the outer peripheral surface 53m of the flange portion 53. That is, the insulating ceramic forming the front end side separator 51 is exposed on the surface. For this reason, as will be described later, the front-end separator 51 and the holding metal fitting 90 are in direct contact with no water-repellent layer interposed.

  On the other hand, the surface (second surface) 55c of the rear end side separator 55 includes a front end surface 55s, a rear end surface 55k, an inner peripheral surface 55n, and an outer peripheral surface 55m. Specifically, the front end surface 55s is a surface that is located at the front end of the rear end side separator 55 and faces the front end side GS. The rear end surface 55k is a surface located at the rear end of the rear end side separator 55 and facing the rear end side GK. The inner peripheral surface 55n is a surface that is located inside the rear end side separator 55 and connects the front end surface 55s and the rear end surface 55k, and the inner peripheral surface 55n forms a rear end side accommodation hole 55h. . The outer peripheral surface 55m is a cylindrical surface that forms the outer periphery of the rear end side separator 55, and connects the front end surface 55s and the rear end surface 55k.

  Of these, the front end surface 55s contacts the front end side separator 51 (specifically, contacts the front surface 52ka of the rear end surface 52k of the main body 52) and the front end side separator 51. And a non-opposing surface 55sb that does not oppose. The outer peripheral surface 55m is divided into a contact surface 55ma that is located on the front end side GS and abuts against the front end side separator 51, and a non-contact surface 55mb that is located on the rear end side GK and is not close to the front end side separator 51. It is done. That is, of the surface 55c of the rear end side separator 55, the facing surface 55sa of the front end surface 55s and the contact surface 55ma of the outer peripheral surface 55m correspond to the above-mentioned “second combination surface”.

  Further, the non-facing surface 55sb of the leading end surface 55s is continued from the facing surface 55sa of the leading end surface 55s, and the rear end side receiving holes 55h forming the rear end side GK portion of the inner receiving hole 50h are opened from the facing surface 55sa. This is a surface extending to each opening edge (second opening edge) 55sf, and corresponds to the aforementioned “second opening adjacent surface”. The non-facing surface 55sb is a surface that faces the facing surface 55sa of the front end surface 55s and faces the front end side GS, and corresponds to the aforementioned “second front end facing surface”.

  Of the surface 55c of the rear end side separator 55, a second water repellent layer 56 having water repellency is formed on the opposing surface 55sa of the front end surface 55s and the contact surface 55ma of the outer peripheral surface 55m, which are “second combination surfaces”. Has been. The second water-repellent layer 56 is a layer having a thickness of about 1 μm formed from an inorganic ceramic material having water repellency, like the first water-repellent layer 54 described above. The second water repellent layer 56 is also formed on the non-opposing surface 55 sb of the front end surface 55 s which is the “second opening adjacent surface” and the “second front end facing surface” of the surface 55 c of the rear end side separator 55. Has been. Accordingly, the second water repellent layer 56 is formed on the entire front end surface 55s of the rear end side separator 55.

  The second water repellent layer 56 is formed as follows. That is, masking is performed on the entire surface of the front end surface 55s and the surface other than the contact surface 55ma of the outer peripheral surface 55m. Then, a coating agent containing a water-repellent inorganic ceramic material is applied to the entire front end surface 55s and the contact surface 55ma of the outer peripheral surface 55m and dried to form the second water repellent layer 56. Then remove the masking.

  On the other hand, of the surface 55c of the rear end side separator 55, the front end surface 55s and the outer peripheral surface 55m other than the contact surface 55ma, that is, the rear end surface 55k, the outer peripheral surface 55m non-contact surface 55mb and the inner peripheral surface 55n. The water repellent layer is not formed. That is, the insulating ceramic forming the rear end side separator 55 is exposed on the surface.

  Next, the holding metal fitting 90 will be described. The holding metal fitting 90 is a metal (specifically, SUS) member that is interposed between the surrounding member 30 and the insulating separator 50 and grips the insulating separator 50 from the outside in the radial direction and holds it on the surrounding member 30. is there. The holding metal fitting 90 is formed in a cylindrical metal fitting outer peripheral portion 91 and a cylindrical metal fitting that is bent radially inward from the rear end side GK of the metal fitting outer peripheral portion 91 and arranged radially inward of the metal fitting outer peripheral portion 91. It consists of a peripheral portion 92 and has a double cylindrical shape connected on one end side.

  The outer periphery 91 of the metal fitting is in contact with the surrounding member 30 on the outer side in the radial direction, and is pressed toward the inner side in the radial direction by the crimping portion 32 that is caulked on the inner side in the radial direction of the surrounding member 30. On the other hand, the metal inner peripheral portion 92 of the insulating separator 50 engages with the front end side tapered surface 53s of the flange portion 53 of the front end side separator 51 from the front end side GS, while the main body portion 52 of the front end side separator 51 is engaged. It contacts the outer peripheral surface 52m. Thereby, the front end side separator 51 and the rear end side separator 55 combined therewith are held by the surrounding member 30 via the holding fitting 90.

  Of the front end side taper surface 53s of the flange 53 of the front end side separator 51 and the outer peripheral surface 52m of the main body portion 52 of the front end side separator 51 that the metal fitting inner peripheral portion 92 contacts and grips, the rear end side GK The rear end side outer peripheral surface 52ma corresponds to the above-described “grip surface”. As described above, the water repellent layer is not formed on the outer peripheral surface 52m including the front end side tapered surface 53s of the flange portion 53 and the rear end side outer peripheral surface 52ma of the main body portion 52. That is, the holding member 90 is in direct contact with the front end side taper surface 53s of the collar portion 53 and the rear end side outer peripheral surface 52ma of the main body portion 52 without using the water repellent layer.

  As described above, in the gas sensor 1 of the present embodiment, of the surface 51c of the front end side separator 51, the opposing surface 52ka of the rear end surface 52k of the main body 52, which is the “first combination surface”, and the flange 53 A first water repellent layer 54 is provided on the peripheral surface 53n. Further, the second water repellent layer 56 is provided on the surface 55 c of the rear end side separator 55 on the facing surface 55 sa of the front end surface 55 s and the contact surface 55 ma of the outer peripheral surface 55 m which are “second combination surfaces”. Thereby, even when dew condensation occurs in the surrounding member 30, a portion of the insulating separator 50 in which the front end side separator 51 and the rear end side separator 55 are combined (between the facing surface 52ka and the facing surface 55sa and inside Water hardly collects between the peripheral surface 53n and the contact surface 55ma. Therefore, due to the water adhering to these portions, the insulation between the terminal members 60 accommodated in the insulating separator 50, the terminal member 60 and the holding bracket 90, and the surrounding member 30 in contact therewith It is possible to prevent the insulating property between the layers from decreasing.

  In addition, in the gas sensor 1, a gripped surface (the front end side tapered surface 53s of the flange portion 53 and the main body) of the surface 51c of the front end side separator 51 and the surface 55c of the rear end side separator 55 that the holding metal fitting 90 comes into contact with and holds. A water repellent layer is not formed on the rear end side outer peripheral surface 52ma) of the outer peripheral surface 52m of the portion 52, and the holding metal fitting 90 is in direct contact with the surface 50c (the gripped surfaces 52ma, 53s) of the insulating separator 50. ing. Accordingly, the holding metal fitting 90 can reliably hold the insulating separator 50.

  Furthermore, in the present embodiment, the surface 51 c of the front end side separator 51 has a non-facing surface 52 kb of the rear end surface 52 k of the main body 52 that is a “first opening adjacent surface”, and the surface of the rear end side separator 55. 55c has a non-facing surface 55sb of the front end surface 55s which is the “second opening adjacent surface”. The first water repellent layer 54 is provided on the non-facing surface (first opening adjacent surface) 52 kb, and the second water repellent layer 56 is provided on the non-facing surface (second opening adjacent surface) 55 sb. This makes it difficult for water to adhere to the opposed surface 52ka and the inner peripheral surface 53n (first combined surface), and the opposed surface 55sa and the contact surface 55ma (second combined surface), as well as the non-opposed surface ( Water also hardly adheres to the first opening adjacent surface) 52 kb and the non-facing surface (second opening adjacent surface) 55 sb. Accordingly, it is possible to more appropriately prevent the insulation between the terminal members 60 and the insulation between the terminal member 60 and the holding metal fitting 90 and the surrounding member 30 from being deteriorated.

  In the present embodiment, the surface 51c of the front end side separator 51 includes the non-opposing surface 52kb of the rear end surface 52k of the main body 52 and the rear end surface 53k of the flange portion 53, which are “first rear end facing surfaces”. On the surface 55c of the rear end side separator 55, there is a non-facing surface 55sb of the front end surface 55s which is a “second front end facing surface”. A first water repellent layer 54 is provided on the non-facing surface 52 kb and the rear end surface 53 k (first rear end facing surface), and a second water repellent layer 56 is provided on the non-facing surface 55 sb (second front end facing surface). Yes. This makes it difficult for water to adhere to the opposed surface 52ka and the inner peripheral surface 53n (first combined surface), and the opposed surface 55sa and the contact surface 55ma (second combined surface), and also the non-opposed surface 52kb. Also, water hardly adheres to the rear end surface 53k (first rear end facing surface) and the non-facing surface (second front end facing surface) 55sb. Accordingly, it is possible to more appropriately prevent the insulation between the terminal members 60 and the insulation between the terminal member 60 and the holding metal fitting 90 and the surrounding member 30 from being deteriorated.

(Examples and Comparative Examples)
Next, the results of an insulation test conducted to verify the effect of the present invention will be described. First, nine gas sensors 1 according to the embodiment were prepared as examples. In the gas sensor 1, as described above, the first combination surface (opposing surface 52ka and inner peripheral surface 53n), the first opening adjacent surface (non-facing surface 52kb), and the first of the surface 51c of the front end-side separator 51. A first water-repellent layer 54 was provided on the rear end facing surface (non-opposing surface 52 kb and rear end surface 53 k). Of the surface 55c of the rear end side separator 55, the second combination surface (opposing surface 55sa and abutment surface 55ma), the second opening adjacent surface (non-opposing surface 55sb), and the second tip-facing surface (non-opposing surface) 55 sb) was provided with a second water repellent layer 56.

As Comparative Example 1, six gas sensors were prepared. In the gas sensor of Comparative Example 1, a water repellent layer was provided on the “entire surface” of the surface 51 c of the front end side separator 51, and a water repellent layer was provided on the “entire surface” of the surface 55 c of the rear end side separator 55. Other than that, it was the same as the gas sensor 1 of the example.
As Comparative Example 2, four gas sensors were prepared. In the gas sensor of Comparative Example 2, the water repellent layer was not provided on any part of the surface 51 c of the front end side separator 51. Further, no water repellent layer was provided on any part of the surface 55 c of the rear end side separator 55. Other than that, it was the same as the gas sensor 1 of the example.

As Comparative Example 3, five gas sensors were prepared. In the gas sensor of Comparative Example 3, the first combination surfaces 52ka and 53n, the first opening adjacent surface 52kb, and the first rear end facing surface of the surface 51c of the front-end separator 51, contrary to the gas sensor 1 of the example. The 52 kb and 53 k were not provided with a water-repellent layer, but were provided with a water-repellent layer in other portions. Further, in the surface 55c of the rear end side separator 55, the second combination surfaces 55sa, 55ma, the second opening adjacent surface 55sb, and the second tip-facing surface 55sb are not provided with a water repellent layer, and other portions are not provided. A water repellent layer was provided. Other than that, it was the same as the gas sensor 1 of the example.
In each of the gas sensors of Examples and Comparative Examples 1 to 3, in order to easily cause condensation in the “insulation test” described below, one drop (1 μl) of water droplets is dropped into the enclosing member 30 at the time of production. After hanging, the surrounding member 30 was sealed.

Next, an “insulation test” was performed for each of the gas sensors of Examples and Comparative Examples 1 to 3. First, for each gas sensor before the test, the lead wire 65 connected to the terminal member 60 connected to one of the electrode pads 47 of the gas detector of the detection element 40 and one of the electrode pads 47 of the heater body are connected. The insulation resistance value at normal temperature with the lead wire 65 connected to the terminal member 60 was measured by applying a voltage of 100V.
Next, each gas sensor was immersed in a bathtub (water tank) so that the whole was immersed in water, and the bathtub was heated with the hot plate. In order to cause dew condensation due to water droplets enclosed in the surrounding member 30, heating for 30 minutes (power ON) and cooling for 90 minutes (power OFF) are repeated 10 times, and the water temperature is 40 ° C to 100 ° C. Periodically fluctuated between. Then, each gas sensor was taken out from the bathtub, and the insulation resistance value at normal temperature between the terminal members 60 was measured in the same manner as before the test. The results are shown in FIGS. 4 shows an example, FIG. 5 shows a comparative example 1, FIG. 6 shows a comparative example 2, and FIG.

  As is apparent from FIGS. 4 to 7, in any of the gas sensors of Examples and Comparative Examples 1 to 3, the insulation resistance decreased after the above “insulation test” was performed. However, compared with the gas sensor of Example and Comparative Example 1, in the gas sensors of Comparative Examples 2 and 3, the decrease in insulation resistance after the test was large and decreased by 3 digits or more. In the gas sensor of the example and the comparative example 1, the water repellent layer is provided in a portion where the front end side separator 51 and the rear end side separator 55 are combined in the insulating separator 50, so that dew condensation occurs in the surrounding member 30. This combination part made it difficult for water to adhere. For this reason, it is thought that it was able to prevent appropriately that the insulation between the terminal members 60 accommodated in the insulation separator 50 fell due to the water adhering to this combination part.

  Although the gas sensor of Comparative Example 1 showed good results in this insulation test, the insulating separator 50 (the front end side separator 51) is attached to the holding bracket 90 when a strong impact is applied to the gas sensor from the outside. It may be easy to come off, the positional deviation occurs in the front end side separator 51 and the rear end side separator 55, and the holding metal fitting 90 may not be able to hold the insulating separator 50 reliably. This is because, in the surface 50c of the insulating separator 50, since the water repellent layer is also provided on the gripped surfaces 52ma and 53s that the holding metal fitting 90 contacts and holds, the holding metal fitting 90 is easy to slip. Therefore, unlike the gas sensor 1 of the embodiment, it is preferable not to provide a water-repellent layer on the gripped surfaces 52ma and 53s.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, of the surface 51c of the front end side separator 51, the first combination surfaces 52ka and 53n, the first opening adjacent surface 52kb, and the first rear end facing surfaces 52kb and 53k, the surface of the rear end side separator 55 55c, the water repellent layers 54 and 56 are provided only on the second combination surfaces 55sa and 55ma, the second opening adjacent surface 55sb, and the second tip-facing surface 55sb, and the entire remaining surface including the gripped surfaces 52ma and 53s. However, the present invention is not limited to this. For example, of the surface 51c of the front end side separator 51 and the surface 55c of the rear end side separator 55, only the gripped surfaces 52ma and 53s, without providing the water repellent layer, the first combination surfaces 52ka and 53n and the second combination surface 55sa. , 55ma and the like may be provided with a water repellent layer. In the embodiment, the insulating separator is configured by two members. However, the embodiment is not limited thereto, and the insulating separator may be configured by three or more members.

1 Gas sensor (sensor)
DESCRIPTION OF SYMBOLS 10 Main metal fitting 20 Protector 30 Enclosing member 40 Detection element 43 Element rear end part 47 Electrode pad 50 Insulation separator 50c (insulation separator) surface 50h Internal accommodation hole 51 Front end side separator (first separator)
51c (first-side separator) surface (first surface)
52 Main body portion 52k (of the front end side separator) Rear end surface 52ka (of the main body portion) Opposing surface (first end surface)
52 kb (rear end face) non-opposing face (first opening adjacent face, first rear face)
52kf opening edge (first opening edge)
52m (outside body) outer peripheral surface 52ma Rear end side outer peripheral surface (grip surface)
53 Edge part 53s (of the tip side separator) Tip side taper surface (the surface to be gripped)
53k Rear end face (face of first buttocks)
53n Inner peripheral surface (proximal surface, first combined surface)
54 1st water repellent layer 55 Rear end side separator (second separator)
55c Surface (second surface) of rear end side separator
55s Front end surface 55sa (at the rear end side separator) Opposing surface (at the front end surface) (second combination surface)
55 sb (front end surface) non-opposing surface (second opening adjacent surface, second tip facing surface)
55sf opening edge (second opening edge)
55m (outer end separator) outer peripheral surface 55ma (outer peripheral surface) contact surface (second combination surface)
56 Second water repellent layer 60 Terminal member 90 Holding metal fitting AX Axis line HJ Axial direction GS (Axial direction) tip side GK (Axial direction) rear end side

Claims (3)

A detection element having a form extending in the axial direction, and having a plurality of electrode pads at the element rear end on the rear end side in the axial direction;
A metal surrounding member surrounding the element rear end of the detection element from the outside in the radial direction perpendicular to the axial direction;
A plurality of terminal members respectively electrically connected to the plurality of electrode pads of the detection element;
An insulating separator made of an insulating ceramic, disposed within the surrounding member, and holding the plurality of terminal members in their internal housing holes while insulating the terminal members from each other;
A holding metal fitting interposed between the surrounding member and the insulating separator and holding the insulating separator from outside in the radial direction and holding the surrounding member on the surrounding member,
The insulating separator is
It is configured by combining a first separator and a second separator that divide the internal accommodation hole,
Of the first surface that is the surface of the first separator, the first combination surface that is combined with the second separator, and among the second surface that is the surface of the second separator, the second surface is combined with the first separator. A water repellent layer having water repellency is formed on the combination surface, and
Of the first surface and the second surface, a sensor in which the holding metal comes into contact directly without forming the water-repellent layer on a gripped surface on which the holding metal comes into contact and holds. The sensor according to claim 1,
On the first surface and the second surface,
The first opening adjacent surface extending from the first combination surface to the first opening edge where the first accommodation hole forming a part of the internal accommodation hole is opened from the first combination surface among the first surfaces. ,as well as,
Of the second surface, following the second combination surface, a second opening adjacent surface extending from the second combination surface to a second opening edge where a second accommodation hole forming a part of the internal accommodation hole opens. , At least one of
A sensor in which the water-repellent layer is also formed on a surface of the first opening adjacent surface and the second opening adjacent surface. The sensor according to claim 1 or 2, wherein
The first separator is a tip side separator,
The second separator is a rear end side separator located on the rear end side in the axial direction of the front end side separator,
On the first surface and the second surface,
Of the first surface, following the first combination surface, the first rear end surface facing the rear end side in the axial direction, and
Of the second surface, there is at least one of a second tip-facing surface following the second combination surface and facing the tip end side in the axial direction,
A sensor in which the water-repellent layer is also formed on a surface existing among the first rear-facing surface and the second front-facing surface.

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