WO2013128801A1

WO2013128801A1 - Gas sensor

Info

Publication number: WO2013128801A1
Application number: PCT/JP2013/000614
Authority: WO
Inventors: 健弘大場; 山田　裕一; 伊藤　慎悟; 大輔多比良; 紘也古田
Original assignee: 日本特殊陶業株式会社
Priority date: 2012-02-29
Filing date: 2013-02-05
Publication date: 2013-09-06
Also published as: JPWO2013128801A1; CN103946700B; CN103946700A; BR112014013317B1; BR112014013317A2; JP5703373B2

Abstract

Provided is a gas sensor whereby, despite a planar sensor element being made less wide, the width of a discharge trench provided to a rear end surface of a sealing member is increased and moisture or oil is reliably discharged. A gas sensor (200) provided with: a planar sensor element (10) having at least two electrode pads (11a-12b); an insulating member (166); terminal fittings (21a-22b) retained by the insulating member and arranged to respectively face the electrode pads; a lead wire (146) electrically connected to the rear end side of the terminal fittings; a sealing member (170) having at least three lead wire insertion holes (170a) and a through hole (170h), the sealing member (170) being arranged at the rear end side of the insulating member; and a filter (174) for blocking off the through hole, wherein at least some of the distances among pitch distances G₁, G₂ of the lead wire insertion holes are longer and a discharge trench (170g) is formed on a rear end surface of the sealing member, the discharge trench extending across the lead wire insertion holes that form the longer pitch distance G₂.

Description

Gas sensor

The present invention relates to a gas sensor including a sensor element that detects the concentration of a gas to be detected.

As a gas sensor for detecting a concentration of a gas to be detected such as oxygen in an exhaust gas of an automobile or the like, a sensor having a cell element extending in the axial direction and having a cell having an oxygen ion-permeable solid electrolyte and a pair of electrodes. Are known.
As this type of gas sensor, an outside air introduction type gas sensor that takes in reference oxygen (atmosphere) that generates a reference potential of the sensor output of the cell from the outside of the gas sensor is known (Patent Documents 1 and 2). For example, as shown in FIG. 11, in the outside air introduction type gas sensor 2000, an air introduction hole 1700h penetrating in the direction of the axis O is formed at the center of a rubber grommet (elastic seal member) 1700 disposed at the rearmost end of the gas sensor. A cylindrical filter retainer 172 is inserted into the air introduction hole 1700h, and a water-repellent air-permeable filter 174 is held between the air introduction hole 1700h and the filter retainer 172. Thereby, the atmosphere is introduced into the gas sensor 2000 through the atmosphere introduction hole 1700h, and the reference potential of the sensor element 10 can be generated.

Here, a plate-like element extending in the direction of the axis O as the sensor element 10 and having an opposing main surface is used, and two

electrode pads

11a and 12a are provided on the rear end side of each main surface of the sensor element 10, respectively. Think about the case.
As shown in FIG. 11, an insulating member 1660 is disposed between the sensor element 10 and the grommet 1700 along the axis O direction, and four pieces (only two in FIG. 11) penetrate in the axis O direction of the insulating member 1660. 4) (only 2 are shown in FIG. 11) of

terminal fittings

21a and 22a are held in the terminal storage holes 1660a. Each of the

terminal fittings

21a and 22a is electrically connected to the electrode pads (only two of the total four shown in FIG. 11) 11a and 12a, and leads to the rear ends of the terminal fittings 21a and 22a. 146 is connected by caulking. Then, the lead wire 146 is inserted into a lead wire insertion hole 1700a (see FIG. 12) provided in the grommet 1700, and is pulled out to take out a sensor output.

By the way, as shown in FIG. 12, the lead wire insertion holes 1700a are also provided in two positions along the

electrode element

11a, 12a and the

terminal fittings

21a, 22a as viewed from the direction of the axis O, that is, along both surfaces of the sensor element 10. Line up one by one. In this case, the pitch-to-pitch distance (interval) G ₁ between the two lead wire insertion holes 1700 a arranged in the width direction of the main surface of the sensor element 10 is a lead facing the direction (thickness direction) perpendicular to the main surface of the sensor element 10. smaller than the pitch distance _{G 2} line insertion hole 1700a.
On the other hand, if moisture, oil, dust, or the like accumulates so as to cover the rear end surface of the filter 174, the air permeability of the filter 174 decreases, and the reference oxygen (atmosphere) cannot be sufficiently taken into the gas sensor 2000. There is a risk of output failure. Therefore, in the case of the gas sensor described in Patent Document 1, although not shown, the pitch distance between the lead wire insertion holes is made equal, and the rear end surface of the grommet communicates with the air introduction hole and the adjacent lead wire insertion. A single discharge groove is formed that extends between the holes to the radially outer edge of the grommet and discharges moisture or oil.
Further, in the case of the gas sensor described in Patent Document 2, a discharge groove serving as a lateral groove is similarly formed not in the rear end face of the grommet 1700 but near the center in the axial direction. The direction of the lateral groove (corresponding to the discharge groove 1700g) is perpendicular to the direction of the main surface of the sensor element 10 as shown in FIG. 12, and faces the width direction of the main surface of the sensor element 10. The lead wire insertion holes 1700a extend across each other.

Japanese Patent Laid-Open No. 2003-194765 (FIG. 7) Japanese Patent Laid-Open No. 2008-232652 (FIG. 5)

However, along with the downsizing of the gas sensor, the sensor element 10 and each component constituting the gas sensor are also narrowed, and the width of the main surface of the sensor element 10 is also narrowed. electrode pads 11a that faces the spacing 12a (see FIG. 11), thus it becomes smaller pitch distance _{G 1} of lead wire insertion hole 1700a, same width W of the discharge groove 1700g crossing between the lead wire insertion hole 1700a Must be narrowed (see FIG. 12). However, when the width W of the discharge groove 1700g becomes narrow, there is a problem that the surface tension becomes high and it becomes difficult for water or oil to be discharged from the discharge groove 1700g to the outside.

Therefore, the present invention provides a gas sensor that can reliably discharge moisture or oil by increasing the width of a discharge groove provided on the rear end surface of a seal member even if the plate-shaped sensor element is narrowed. With the goal.

In order to solve the above problems, a gas sensor according to the present invention has a plate-like shape extending in the axial direction and having opposing main surfaces, and two or more electrode pads on the rear end side of each main surface, A cylindrical insulating member made of an insulating material, disposed on the rear end side of the sensor element, a terminal metal fitting held by the insulating member and opposed to the electrode pad, and A lead wire electrically connected to a rear end side, three or more lead wire insertion holes arranged on the rear end side of the insulating member, penetrating in the axial direction and inserted through the lead wires, and A gas sensor comprising at least a cylindrical sealing member having a through-hole penetrating in the axial direction at a position radially inward of the lead wire insertion hole, and a water-repellent filter that closes the through-hole, 3 or more The three or more lead wire insertion holes are arranged so that at least a part of the distance between the pitches of the lead wire insertion holes is longer, and a rear end surface of the seal member is provided with the air introduction hole. A discharge groove that communicates and extends to the outer edge in the radial direction of the seal member to discharge moisture or oil is formed, and the discharge groove forms a distance between pitches that increases the distance among the distances between the pitches. It extends across between the insertion holes.
According to this gas sensor, along with the downsizing of the gas sensor, the width and thickness of the main surface of the sensor element, that is, the distance between the electrode pads of the sensor element is narrowed, and as a result, the distance between the pitches of the corresponding lead wire insertion holes. Can be provided between the lead wire insertion holes that form a pitch-to-pitch distance that increases the distance, and the width of the discharge groove can be widened to reliably discharge moisture or oil. .

It is preferable that the width of the discharge groove is wider than the shortest pitch distance among the pitch distances, since the width of the discharge groove can be surely increased even if the sensor element is narrowed.

Further, it is preferable that the inner diameter of the through-hole is larger than the shortest pitch distance among the pitch distances, since air permeability can be improved reliably even if the sensor element is narrowed.

Further, when the width of the discharge groove is narrower than the inner diameter of the through hole, the filter can be protected from the impact of flying stones and the like from the outside in the radial direction by the seal member and can be stably held.

The filter holder further includes a substantially cylindrical filter fitted into the through hole, the filter is held by at least the filter holder, the discharge groove surrounds the periphery of the through hole, and the filter The rear end surface may be positioned between the rear end surface of the seal member and the surface of the discharge groove in the axial direction.
According to this gas sensor, although the discharge groove surrounds the periphery of the through hole, the filter does not contact the seal member on the rear end side from the rear end facing surface of the discharge groove, so the filter penetrates the filter through the filter clasp. When inserted into the hole, the friction between the filter and the side wall of the seal member is reduced on the rear end side from the surface facing the rear end of the discharge groove, and the filter is prevented from being damaged. Furthermore, the rate at which the filter rubs against the side wall of the seal member due to vibration during use of the gas sensor is reduced, and damage to the filter due to vibration is also suppressed.

The filter holder further includes a substantially cylindrical filter fitted into the through hole, the filter is held by at least the filter holder, the discharge groove surrounds the periphery of the through hole, and the filter The rear end surface may be located at the same position as the surface of the discharge groove in the axial direction or at the front end side.
According to this gas sensor, since the filter is located at the same position as the discharge groove or at the tip side of the discharge groove, even if it receives high-pressure water discharge from the radial direction, it does not directly apply to the filter. Damage can be prevented.

According to the present invention, even if the width of the main surface of the plate-like sensor element is narrowed, a gas sensor that reliably discharges moisture or oil by increasing the width of the discharge groove provided on the rear end surface of the seal member is obtained. It is done.

It is sectional drawing which follows the longitudinal direction of the gas sensor which concerns on embodiment of this invention. It is a perspective view of a sensor element. It is a bottom view of the separator seen from the front end side. It is a top view of the grommet seen from the rear end side. It is the upper surface perspective view of the grommet seen from the rear end side. It is a section perspective view in the state where a terminal metal fitting was built in a separator. It is an upper surface perspective view when the grommet in which the filter was hold | maintained in 1st Embodiment of this invention was seen from the rear end side. It is a top view when the grommet holding the filter is viewed from the rear end side. It is a perspective view of the sensor element which has five electrode pads. FIG. 10 is a top view of the grommet used in the sensor element of FIG. 9 and viewed from the rear end side. It is sectional drawing in alignment with the longitudinal direction of the conventional gas sensor. It is the top view seen from the rear end side of the grommet used for the conventional gas sensor. It is an upper surface perspective view when the grommet with which the filter was hold | maintained in 2nd Embodiment of this invention is seen from the rear end side.

Hereinafter, embodiments of the present invention will be described.
1 is an overall cross-sectional view of the gas sensor (oxygen sensor) 200 according to an embodiment of the present invention along the longitudinal direction, FIG. 2 is a perspective view of the sensor element 10, and FIG. 3 is a bottom view of the separator 166 as viewed from the front end side. 4 is a top view of the grommet 170 viewed from the rear end side, FIG. 5 is a top perspective view of the grommet 170 viewed from the rear end side, and FIG. 6 is a cross-sectional perspective view of the state in which 21a, 21b, 22a, 22b are incorporated in the separator 166. 7 is a top perspective view when the grommet 170 holding the filter 174 is viewed from the rear end side, and FIG. 8 is a top view when the grommet 170 holding the filter 174 is viewed from the rear end side. .
The gas sensor 200 is an oxygen sensor that detects the oxygen concentration in the exhaust gas of automobiles and various internal combustion engines, and includes a cell (not shown) having a solid electrolyte that is permeable to oxygen ions and a pair of electrodes. The element 10 is included. The reference potential of the sensor output of this cell is based on reference oxygen (atmosphere) taken from the outside of the gas sensor.
As will be described later, the sensor element 10 has a plate shape extending in the axial direction, and has two or more (total of four or more) electrode pads in the width direction on the rear end side of each plate surface.

In FIG. 1, the gas sensor 200 includes a cylindrical metal shell 138 having a threaded portion 139 formed on the outer surface for fixing to an exhaust pipe, and an axis O direction (longitudinal direction of the gas sensor 200: up and down direction in the figure). A sensor element 10 having a plate-like shape that extends, a cylindrical ceramic sleeve 106 disposed so as to surround the periphery of the sensor element 10 in the radial direction, and the inside of the distal end side of the through-hole 168 penetrating in the axial direction are provided. 10, a ceramic separator (an “insulating member” in the claims) 166 disposed so as to surround the rear end of the sensor 10, and four terminal fittings disposed between the sensor element 10 and the separator 166. 21a, 21b, 22a, 22b (only two are shown in FIG. 1).
Further, the gas detection portion 10a at the tip of the sensor element 10 is covered with a porous protective layer 20 such as alumina.

The metal shell 138 is made of stainless steel, has an insertion hole 154 penetrating in the axial direction, and has a substantially cylindrical shape having a shelf 152 protruding radially inward of the insertion hole 154. The sensor element 10 is inserted into the insertion hole 154 so that the tip of the sensor element 10 protrudes from the tip of the sensor element 10. Further, the shelf portion 152 is formed as an inwardly tapered surface having an inclination with respect to a plane perpendicular to the axial direction.

In addition, inside the insertion hole 154 of the metal shell 138, an annular ceramic holder 151 made of alumina and powder filling layers 153 and 156 (hereinafter referred to as talc rings 153 and 156) surrounding the sensor element 10 in the radial direction. The ceramic sleeve 106 is laminated in this order from the front end side to the rear end side.
A caulking packing 157 is disposed between the ceramic sleeve 106 and the rear end portion 140 of the metal shell 138, and a talc ring 153 is disposed between the ceramic holder 151 and the shelf 152 of the metal shell 138. And a metal holder 158 for holding the ceramic holder 151 is disposed. Note that the rear end portion 140 of the metal shell 138 is crimped so as to press the ceramic sleeve 106 toward the distal end side via the crimping packing 157.

On the other hand, as shown in FIG. 1, a metal (for example, stainless steel) 2 having a plurality of holes and covering the protruding portion of the sensor element 10 on the outer periphery of the front end side (downward in FIG. 1) of the metal shell 138. An external protector 142 and an internal protector 143, which are heavy protectors, are attached by welding or the like.

An outer cylinder 144 is fixed to the outer periphery of the rear end side of the metal shell 138. Further, the four

terminal fittings

21a, 21b, 22a, and 22b (only two are shown in FIG. 1) of the sensor element 10 are respectively provided in the opening on the rear end side (upper side in FIG. 1) of the outer cylinder 144. An elastic rubber tubular grommet (not shown) formed with lead wire insertion holes (not shown) through which four lead wires 146 (only two are shown in FIG. 1) are electrically connected. The “sealing member” 170) of the claims is arranged.
Further, a circular air introduction hole (a “through hole” in the claims) 170 h for introducing the air serving as a reference atmosphere is formed at the axial center of the grommet 170, and the air introduction hole 170 h is made of metal. A cylindrical filter clip 172 is inserted. A water-repellent air-permeable filter 174 that allows air to pass but does not pass water is held between the air introduction hole 170h and the filter clasp 172. Air can be introduced into and out of the gas sensor 200 through the air introduction hole 170h. It has become. The filter clip 172 may be made of resin instead of metal.

Further, a separator 166 is disposed on the rear end side (upper side in FIG. 1) of the sensor element 10 protruding from the rear end portion 140 of the metal shell 138. The separator 166 is disposed around a total of four electrode pads (only two

electrode pads

11a and 12a are shown in FIG. 1) formed on the main surface on the rear end side of the sensor element 10. The separator 166 is formed in a cylindrical shape having a through-hole 168 penetrating in the axial direction, and is provided with a flange portion 167 that protrudes radially outward from the outer surface. The separator 166 is held inside the outer cylinder 144 by the flange portion 167 coming into contact with the outer cylinder 144 via the holding member 169.

As shown in FIG. 2, the sensor element 10 has a plate shape extending in the direction of the axis O, the tip portion 10 s is a gas detection portion 10 a that detects the oxygen concentration, and the gas detection portion 10 a is a porous protective layer 20. Covered. The sensor element 10 itself has a known configuration, and although not shown, the gas detector having an oxygen ion permeable solid electrolyte body and a pair of electrodes, and the gas detector are heated and maintained at a constant temperature. And a heater unit.
Two

electrode pads

11a and 11b are arranged in the width direction on the rear end side of one surface 10A of the sensor element 10, and a sensor output signal from the gas detection unit 10a is passed through a lead part (not shown). Output from these

electrode pads

11a and 11b. In addition, two

electrode pads

12a and 12b are arranged in the width direction on the rear end side of the other main surface 10B provided so as to face the main surface 10A, and a heater portion is provided via a lead portion (not shown). It is designed to supply power.
Each

electrode pad

11a, 11b, 12a, 12b has a rectangular shape that is long in the direction of the axis O, and can be formed as a sintered body mainly composed of Pt, for example.

FIG. 3 shows a bottom view of the separator 166 viewed from the front end side. In the center of the separator 166, a rectangular through hole 168 having substantially the same shape as the cross section of the sensor element 10 passes through in the axial direction. Then, on the radially outer side of the through hole 168, two terminal storage holes 166a each consisting of a rectangular hole are arranged along each of the two long sides of the through hole 168 (four in total), and each terminal storage hole 166a has an axis line. It penetrates in the direction.
Furthermore, an H-shaped groove portion that recedes stepwise from the forefront of the separator 166 is formed in a portion between the through hole 168 and the four terminal storage holes 166a, and the rear end side of this groove portion is a terminal storage hole. A side wall 166b is formed that communicates with 166a and surrounds each terminal storage hole 166a. In addition, a portion of the groove portion that is radially inward of each terminal storage hole 166a is positioned on the front end side with respect to the peripheral edge of the terminal storage hole 166a and forms a shelf-shaped front-facing surface 166s.

FIG. 4 shows a top view of the grommet 170 viewed from the rear end side. A circular atmospheric introduction hole 170h penetrates in the center of the grommet 170 in the axial direction. Further, two (four in total) circular lead wire insertion holes 170a pass through the outside of the air introduction hole 170h in the radial direction at positions almost overlapping with the terminal storage holes 166a of the separator 166 when viewed from the axis O direction. ing. Each lead wire insertion hole 170a is located respectively in a rectangular vertex pitch distance (interval) G ₂ of the two lead wire insertion hole 170a which faces in a direction perpendicular (thickness direction) to the main surface of the sensor element 10 , greater than the pitch distance between G ₁ of lead wire insertion hole 170a opposed to the direction of the main surface. That is, the inter-pitch distance G ₁ corresponds to the “distance between the shortest pitches” in the claims, and the inter-pitch distance G ₂ corresponds to the “distance between the pitches where the distance becomes longer” in the claims. To do. The pitch distance between the lead wire insertion holes 170a refers to the shortest interval between the peripheral edges of the adjacent lead wire insertion holes 170a.
On the other hand, two lead wire insertion holes that communicate with the rear end surface 170t of the grommet 170 in the atmosphere introduction hole 170h and that intersect with the main surface of the sensor element 10 and in the thickness direction of the main surface of the sensor element 10 One discharge groove 170g extending across each of 170a is formed. The discharge groove 170g extends to the radial outer edge 170e of the grommet 170, and discharges moisture, oil, dust or the like accumulated near the atmosphere introduction hole 170h to the outside from the radial outer edge 170e. In addition, a flange portion 170f that protrudes radially outward from the radially outer edge 170e is provided at the tip of the grommet 170, and the outer tube 144 that covers the flange portion 170f is caulked so that the inside of the outer tube 144 is provided. Is held (see FIG. 1).
In the first embodiment, the discharge groove 170g has a linear shape passing through the air introduction hole 170h. Further, the direction in which the discharge groove 170g extends is parallel to the main surface of the sensor element 10, but is not limited thereto.

In the first embodiment, the discharge groove 170g surrounds the periphery of the air introduction hole 170h, and the width W of the discharge groove 170g is narrower than the inner diameter d of the air introduction hole 170h. Furthermore, the width W of the discharge groove 170g is wider than the pitch distance between _{G 1} of lead wire insertion hole 170a opposed to the direction of the main surface of the sensor element 10. FIG. 5 is a top perspective view of the grommet 170 viewed from the rear end side. The rear end facing surface 170gt of the discharge groove 170g is located on the rear end side with respect to the center of the grommet 170 in the axis O direction, and more specifically on the rear end edge of the outer cylinder 144 (see FIG. 1). ing. Thereby, moisture, oil, dust, or the like is discharged from the discharge groove 170g without being blocked by the outer cylinder 144.

FIG. 6 shows a cross-sectional perspective view of the state in which the

terminal fittings

21a, 21b, 22a, 22b are incorporated in the separator 166. FIG. The

terminal fittings

21a, 21b, 22a, and 22b are held in the terminal receiving holes 166a of the separator 166 in a state of being isolated so as not to contact each other, and face the front end side of the through hole 168.
Further, the terminal fitting 21a (the same applies to the other

terminal fittings

21b, 22a, and 22b) extends in the direction of the axis O as a whole, and the tip portion folded back from the tip edge toward the rear end serves as the electrode pad of the sensor element 10. Touch. The rear end of the terminal fitting 21a is crimped to the lead wire 146, and the lead wire 146 is drawn out to the rear end side through the lead wire insertion hole 170a of the grommet 170.
Here, when the terminal fitting 21a (the same applies to the

terminal fittings

21b, 22a, and 22b) is inserted into the terminal receiving hole 166a from the front end side, a pair of disconnections extending from the vicinity of the center of the terminal fitting 21a in the axis O direction toward the sensor element 10. The rear end facing surface 211t of the stopper 211d contacts the front end facing surface 166s of the separator 166. Thus, the terminal fitting 21a is prevented from coming out to the rear end side from the front end facing surface 166s, and the position of the terminal fitting 21a is regulated in the axis O direction.
In addition, a slit is formed in the plate surface of each retaining portion 211d to form a locking portion 211w, and the pair of locking portions 211w expand in the groove portion 166b and abut against the side wall of the groove portion 166b, and the separator 166 The terminal fitting 21a is positioned and held inside.

FIG. 7 is a top perspective view of the grommet 170 assembled to the gas sensor as described above and holding the filter 174 when viewed from the rear end side. The rear end surface 174t of the filter 174 is located between the rear end surface 170t of the grommet 170 and the rear end facing surface 170gt of the discharge groove 170g in the axis O direction.
FIG. 8 shows a top view of the grommet 170 holding the filter 174 when viewed from the rear end side. The discharge groove 170g surrounds the periphery of the air introduction hole 170h, and the filter 174 is held by the grommet 170 via the filter clasp 172 so as to be in contact with the air introduction hole 170h. Therefore, the filter 174 is exposed without contacting the grommet 170 on the rear end side from the rear end facing surface 170gt of the discharge groove 170g.

As described above, the discharge groove 170g extends across the two lead wire insertion holes 170a facing each other in the thickness direction of the main surface of the sensor element 10. Therefore, I coupled with the miniaturization of the gas sensor, the width and thickness of the sensor element 10, i.e. the interval of the electrode pads of the sensor element is narrowed, narrow pitch distance G ₁ of the lead wire insertion holes 170a corresponding in turn even now it can be provided with a discharge groove 170g between the two lead wire insertion hole 170a to form a pitch distance G ₂ distance than the pitch distance G ₁ is longer, wider the width W of the discharge groove 170g Thus, moisture or oil can be reliably discharged.
In particular, it is preferable that the width W is wider than the pitch distance G _1.
In the first embodiment, the discharge groove 170g surrounds the periphery of the air introduction hole 170h, and the rear end surface 174t of the filter 174 faces the rear end surface 170t of the grommet 170 and the rear end of the discharge groove 170g in the axis O direction. Located between the surface 170gt. For this reason, the filter 174 does not contact the grommet 170 on the rear end side from the rear end facing surface 170gt of the discharge groove 170g. Therefore, when the filter 174 is inserted into the air introduction hole 170h via the filter clasp 172, Friction between 174 and the side wall of the air introduction hole 170h is reduced, and damage to the filter 174 is suppressed. Furthermore, the rate at which the filter 174 rubs against the side wall of the air introduction hole 170h due to vibration during use of the gas sensor is reduced, and damage to the filter 174 due to vibration is suppressed.
In the first embodiment, the width W of the discharge groove 170g is narrower than the inner diameter d of the air introduction hole 170h. For this reason, especially with a sealing member, while being able to protect a filter from impacts, such as a flying stone from a radial direction outer side, it can hold | maintain stably.

Next, the configuration of the grommet 170x in the case where the sensor element 10x has five electrode pads will be described with reference to FIGS.
FIG. 9 is a perspective view of a sensor element 10x having five electrode pads. The sensor element 10x is the same as the sensor element 10 in FIG. 2 except that three

electrode pads

11a, 11e, and 11b are arranged in this order on the rear end side of one surface 10A in the width direction. The same reference numerals are given and the description is omitted. For example, in the full-range air-fuel ratio sensor, the electrode pad 11e is connected to a line that outputs a reference voltage to the control side system.
In addition, the distance between the electrode pad 11e and the electrode pad 11b is narrower than the distance between the electrode pad 11a and the electrode pad 11e along the width direction of the sensor element 10x.

FIG. 10 shows a top view of the grommet 170x viewed from the rear end side. A substantially circular atmospheric introduction hole 170hx penetrates in the axial direction at the center of the grommet 170x. Then, two lead wire insertion holes 170ax are arranged along the surface 10B of the sensor element 10x on the radially outer side of the air introduction hole 170hx (on the right side of the sensor element 10x in FIG. 10). On the other hand, two lead wire insertion holes 170ax and one lead wire insertion hole 170ax2 corresponding to the

electrode pads

11a, 11e, and 11b along the surface 10A of the sensor element 10x on the radially outer side of the air introduction hole 170hx. Are lined up. Here, the two lead wire insertion holes 170ax corresponding to the

electrode pads

11a and 11b are farthest in the direction of the surface 10A of the sensor element 10x. In addition, one lead wire insertion hole 170ax2 corresponding to the electrode pad 11e is provided between the two lead wire insertion holes 170ax. Further, the lead wire insertion hole 170ax2 is located radially outside the position connecting the two lead wire insertion holes 170ax on the surface 10A side, and does not interfere with the air introduction hole 170hx.

In grommet 170x, the electrode pad 11b, the pitch distance _{G 2} between two lead wire insertion holes 170ax corresponding to 12b, the electrode pads arranged in the same side of the sensor element 10x (e.g., the electrode pad 12b in a surface 10B side and a lead wire insertion holes 170ax corresponding to, greater than the pitch distance between _{G 1} of the lead wire insertion holes 170Ax2) corresponding to the electrode pads 12a. Similarly, the electrode pads 11a, the pitch distance _{G 3} of lead wire insertion holes 170ax corresponding to 12a also greater than the pitch distance between _{G 1.}
That is, the inter-pitch distance G ₁ corresponds to the “distance between the shortest pitches” in the claims, and the inter-pitch distances G ₂ and G ₃ are the “distance between the pitches where the distance becomes longer” in the claims. Is equivalent to.
Incidentally, the three electrode pads 11a arranged on the same surface 10A side of the

sensor element

10x, 11e, lead wire insertion holes 170ax corresponding to 11b, even the pitch distance between 170ax2,170ax is _{G 1.} In the example of FIG. 10, the pitch distance G ₃ = G ₂ > G ₁ is satisfied, but the pitch distance G ₃ ≠ G ₂ > G ₁ may be satisfied.

The discharge groove 170gx is not linear, but has a V shape that is bent at the air introduction hole 170hx. Of the discharge grooves 170gx, for example, there is no lower portion in FIG. 10, that is, only one discharge groove 170gx may be provided across the air introduction hole 170hx. However, in this case, since the drainage effect by the discharge groove 170gx is weakened, a gas sensor may be attached so that the discharge groove 170gx is arranged in the direction of gravity.
Thus, even in the grommet 170x, the discharge groove 170gx the distance extends across each between the lead wire insertion holes 170ax to form a pitch distance _{G 2} and _{G 3} becomes longer. Therefore, the most distance to form a short pitch distance G ₁ of between lead wire insertion holes 170ax compared with the case of providing the discharge groove, possible to reliably discharge the moisture or oil by widening the width W of the discharge groove 170gx Can do. In addition, by providing a plurality of discharge grooves in this way (for example, two discharge grooves 170gx are provided with the air introduction hole 170hx interposed therebetween), it is not necessary to consider the position directionality when mounting the vehicle.

Next, a second embodiment of the present invention will be described with reference to FIG. Note that only the configuration different from the first embodiment will be referred to, and the description of the same configuration will be omitted.
FIG. 13 is a top perspective view of the grommet 180 holding the filter when viewed from the rear end side. The rear end surface 188t of the filter is located at the same position as the rear end facing surface 180gt of the discharge groove 180g of the grommet 180 in the axis O direction.
By adopting such a configuration, even if the gas sensor receives high-pressure water discharge from the radial direction, it is not directly applied to the filter, so that damage to the filter can be prevented.

It goes without saying that the present invention is not limited to the above-described embodiment, but extends to various modifications and equivalents included in the spirit and scope of the present invention.
For example, in the embodiment of FIG. 4 above, the two lead wire insertion holes (four in total) that are the farthest in the thickness direction of the main surface of the sensor element are located at each vertex of the rectangle. The position of the line insertion hole may not be at each vertex of the rectangle, and the distance between the pitches of the two lead wire insertion holes farthest in the direction of the plate surface may be different. For example, in the embodiment of FIG. 4 described above, since the four lead wire insertion holes are located at each vertex of the rectangle, the distance between the pitches of the two sets of lead wire insertion holes facing each other in the thickness direction of the main surface is equal. (Both are G ₂ ), these may be different. Moreover, in 2nd Embodiment, although the rear-end surface 188t of the filter was demonstrated in the aspect located in the same position as the rear-end facing surface 180gt of the discharge groove 180g of the grommet 180 in the axis line O direction, The grommet 180 may be positioned on the front end side with respect to the rear end facing surface 180gt of the discharge groove 180g.

10, 10x sensor element 10A One surface (main surface) of sensor element
10B Other surface (main surface) of sensor element
11a, 11b, 11e, 12a,

12b Electrode pad

21a, 21b, 22a, 22b Terminal fitting 146 Lead wire 166 Insulating member (separator)
170, 170x, 180 Sealing member (grommet)
170a, 170ax, 170ax2, 180a Lead wire insertion hole 170g, 170gx, 180g Discharge groove 170gt, 180gt Rear end face of discharge groove 170h, 170hx Air introduction hole (through hole)
170t, 180t Rear end surface of seal member 172 Filter retainer 174

Filter

174t, 188t Rear end surface of filter 200 Gas sensor O Axial direction d Inner diameter of air introduction hole G ₁ Distance between pitches G ₂ and G _{3 with} the shortest distance becomes longer Distance between pitches W Width of discharge groove

Claims

A sensor element that extends in the axial direction and has a plate-like shape having opposing main surfaces, each having two or more electrode pads on the rear end side of each main surface;
A cylindrical insulating member disposed on the rear end side of the sensor element and made of an insulating material;
Terminal fittings that are held by the insulating member and arranged to face the electrode pads, respectively,
A lead wire electrically connected to the rear end side of the terminal fitting;
Three or more lead wire insertion holes, which are arranged on the rear end side of the insulating member and penetrate in the axial direction and are inserted through the lead wires, respectively, and in the axial direction at positions radially inward from the lead wire insertion holes A cylindrical sealing member having a through-hole penetrating;
A water-repellent filter that closes the through hole;
A gas sensor comprising at least
The three or more lead wire insertion holes are arranged such that at least a part of the distance between pitches of the three or more lead wire insertion holes is long,
On the rear end surface of the seal member, a discharge groove is formed which communicates with the air introduction hole and extends to a radially outer edge of the seal member to discharge moisture or oil.
The exhaust groove is a gas sensor that extends across between lead wire insertion holes that form a pitch-to-pitch distance that increases the distance among the pitch-to-pitch distances.
The gas sensor according to claim 1, wherein the width of the discharge groove is wider than the shortest pitch distance among the pitch distances.
The gas sensor according to claim 1 or 2, wherein an inner diameter of the through hole is wider than a shortest pitch distance among the pitch distances.
The gas sensor according to claim 1 or 2, wherein a width of the discharge groove is narrower than an inner diameter of the through hole.
Further comprising a substantially cylindrical filter fastener fitted into the through hole, the filter is held by at least the filter fastener,
The discharge groove surrounds the periphery of the through hole, and the rear end surface of the filter is located between the rear end surface of the seal member and the surface of the discharge groove in the axial direction. The gas sensor described in 1.
Further comprising a substantially cylindrical filter fastener fitted into the through hole, the filter is held by at least the filter fastener,
5. The discharge groove according to claim 1, wherein the discharge groove surrounds the periphery of the through hole, and the rear end surface of the filter is located at the same position as the discharge groove surface in the axial direction or at the front end side. Gas sensor.