JP2013200263A - Method of manufacturing sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent solder for soldering an annular member from spreading to deposit on a rear end surface or a front end surface of the annular member, in a sensor in which the annular member is soldered to a tube and is pressed to an annular seat surface at the depth of a screw hole by externally fitting a hollow bolt member as a separate component to the annular member and screwing the hollow bolt member into the screw hole and is thereby attached while securing sealability.SOLUTION: In a portion nearer to an inner peripheral edge of a rear end surface 35 of an annular member 31, a backward projecting annular projection 36 is integrally formed which can be put into a hollow part at the front end of a hollow bolt member by clearance fit and is concentric with an inner peripheral surface 32a of the annular member 31. When an outer peripheral surface 15a of a tube 11 and the inner peripheral surface 32a of the annular member 31 are soldered, the tube 11 is stood with its front end down, and a solder material 220 is deposited in the vicinity of an end surface 36a of the annular projection 36 and is fused. The fused solder is stopped after wetting an outer peripheral surface 36b of the annular projection 36.

Description

  The present invention relates to a method for manufacturing a sensor for measuring the temperature of a fluid such as engine exhaust gas. Specifically, a sensor element such as a thermistor (hereinafter also referred to as a sensor element or simply an element) is disposed at a tip or a portion near the tip in a tube (bottomed tube or cap) with a closed tip, and is near the tip of the tube. The temperature of the gas is measured (detected) by attaching it to the installation target part such as an exhaust manifold (exhaust gas pipe) so that the part is exposed to the heat of the exhaust gas, and transferring the heat to the internal sensor element. It is related with the manufacturing method of a suitable sensor.

  Conventionally, sensors of various structures have been proposed as this type of sensor, for example, a temperature sensor (see, for example, Patent Document 1). In the sensor disclosed in Patent Document 1, an annular mounting bracket (housing) having a screw on the outer peripheral surface is provided on a metal tube (protection tube) in which a temperature sensor element is disposed inside a tip (closed end) side. It has a structure that is externally fitted and brazed between the inner and outer peripheral surfaces of both. The annular mounting bracket includes a screw engaging tool engaging portion provided behind the screw. Thus, this sensor is formed by threading the tool engaging portion of the annular mounting bracket, and penetrating and forming a mounting target site such as an exhaust manifold (a boss provided in a protruding manner on the outer peripheral surface) via the screw. It is attached directly by screwing into the screw hole and used for measuring the temperature of exhaust gas.

  By the way, securing of the inner and outer seals (airtightness) in such a sensor attachment target part (exhaust manifold) is performed as follows. That is, at the time of the screwing, a sealing washer is externally fitted and mounted on the tip-facing surface of the tool engaging portion behind the screw of the annular mounting bracket. By doing so, the washer is compressed and deformed by screwing between the tool engaging portion and the end surface of the boss that forms the peripheral edge surface of the screw hole, thereby ensuring a seal therebetween. It is.

  By the way, in mounting the sensor having such a configuration by screwing, the temperature sensor itself is rotated around the axis of the screw. For this reason, in the mounting operation, not only the temperature sensor itself is rotated, but also the lead wire for taking out an electric signal drawn from the rear end of the tube in the sensor is rotated together with the sensor. Including the above, the conventional sensor described above has a problem in that it is subject to various restrictions in mounting in screwing.

  In such a case, like the sensor 100 shown in FIG. 13, the tube 11 includes a tube 11 in which a simple ring-shaped annular member (flange) 31 is fixed to an intermediate portion by brazing. In this case, a hollow bolt member 301 which is a separate part is externally fitted to the tube 11 with a gap from behind, and a screw hole (hereinafter also simply referred to as a screw hole) in an attachment target portion (for example, an exhaust manifold) 500. The screwed member 510 is pressed, and the brazed annular member 31 is pressed by the tip 305 of the bolt member 301. That is, by screwing with the hollow bolt member 301 which is a separate part, the tip-facing surface 33 of the annular member 31 fixed to the tube 11 is strongly pressed (adhered by metal contact) to the annular seating surface 520 at the back of the screw hole 510. This is to secure and attach the seal. According to such an attachment method, since it is not necessary to rotate the sensor itself, it is not necessary to rotate the rear lead wire 51.

Japanese Patent Laid-Open No. 07-140012

  However, in mounting with such a configuration, the surface 33 facing the tip of the annular member 31 requires a high degree of finished surface roughness in order to secure the seal. Note that the annular seating surface 520 at the back of the screw hole 510 is often a tapered tapered seating surface as shown in FIG. Therefore, the tip-facing surface 33 of the annular member 31 pressed against this is tapered correspondingly.

  On the other hand, the hollow bolt member 301 presses the rear end facing surface 35 of the annular member 31 at the tip 305 thereof. For this reason, the rear end facing surface 35 of the annular member 31 becomes a pressure receiving surface (pressed surface) that receives the pressing pressure (tightening force) while being accompanied by frictional resistance due to slip of the tip 305 due to the screwing of the hollow bolt member 301. . On the other hand, the screwing torque for applying such pressing pressure is set to a constant value for the sensor mounting operation and the standardization of the sealing performance. Therefore, in order to apply a constant tightening force, a high degree of finished surface roughness is also required for the rear end facing surface 35 of the annular member 31 that forms the pressure receiving surface.

  By the way, in the process of externally fitting the annular member 31 constituting the sensor 100 to the tube 11 and brazing, the molten brazing is performed using a capillary phenomenon in the gap between the inner peripheral surface of the annular member 31 and the outer peripheral surface of the tube 11. Will be poured. In this case, the melted wax sometimes spreads and adheres to the front end facing surface 33 or the rear end facing surface 35 of the annular member 31 or both. Thus, when the solder adheres to the front-facing surface 33 or the rear-facing surface 35 of the annular member 31, the surface roughness is reduced (even if the surface is finished to a high degree) (smoothness is reduced). Will be damaged). On the other hand, even if the wax adheres to the front-facing surface 33 or the rear-facing surface 35, it is a position very close to the inner peripheral surface 32a of the tube insertion hole, which is the inner side of the annular member 31, and the seal or push There is no problem if it is in a position where pressure is not received. However, if both of the surfaces 33 and 35 are widely spread and adhered to the outside, the above-described sensor cannot obtain a desired sealing performance due to its mounting structure. This is because, if there is a wax adhering to the rear end facing surface, even if a predetermined torque is applied to the hollow bolt member, a predetermined pressing force cannot be obtained due to an increase in frictional resistance. Moreover, if there is uneven adhesion, the uniformity of the pressing force (surface pressure) against the rear end facing surface cannot be obtained. In addition, when there is adhesion of wax on the tip-facing surface, the problem is even greater. Details of the cause or process of the occurrence of these problems are as follows.

  In the manufacturing process of this type of sensor, in order to externally fit and braze the annular member to the tube, the operation is performed as follows. As an example, first, as shown in the left diagram of FIG. 14, the tube 11 is set up vertically, and the annular member 31 is externally fitted to the tube 11 and positioned in the front-rear direction. As shown in the figure, for example, when standing with the tip (closed end) 12 of the tube 11 down, the tip 12 of the tube 11 is brought into contact with the base surface 201 and the downward surface of the annular member 31 ( The tip-facing surface 33) is supported by a support jig 211 placed on the base surface 201.

  Next, it is the rear end facing surface 35 that forms an upward surface of the annular member 31, along the circumferential direction of the tube 11 at or near the corner angle formed with the outer peripheral surface 15 a of the inserted tube 11. An appropriate amount of brazing material 220 is disposed. For example, when the brazing material is copper brazing and is a wire rod or a ring, the brazing material is arranged along the outer peripheral surface of the tube 11 on the rear end facing surface 35 of the annular member 31. Then, the wax is melted by heating in a reflow furnace (vacuum furnace) at a predetermined temperature for a predetermined time. In this way, the molten wax flows and spreads so as to be drawn by capillary action into a minute gap between the inner peripheral surface 32 a of the tube insertion hole inside the annular member 31 and the outer peripheral surface 15 a of the tube 11. When Ni brazing is used for the brazing material, a paste-like brazing material is used, but in this case, it is applied.

  However, in the process of brazing as described above, as shown in the right view (enlarged view) of FIG. 14, the molten solder 230 partially flows out from the rear end of the upper end of the gap, and the annular member 31. May spread and adhere to the rear end-facing surface 35. This is because, in the above brazing, the brazing material 220 is installed on the rear-facing surface 35 that is the upward surface of the annular member 31, so that the molten braze is installed at the start of melting (immediately after melting). This is because a part is unavoidably spread from the position to the outside (outer peripheral direction) on the rear end-facing surface 35. In particular, when a paste-like brazing material such as Ni brazing is used, such a problem is likely to occur on the rear end-facing surface of the annular member because its volume increases.

  On the other hand, when brazing the tube 11 with its rear end facing down, the brazing material is arranged along the outer peripheral surface of the tube 11 at the tip-facing surface 33 of the annular member 31. Then, this is melted and brazed. For this reason, in this case, for the same reason as described above, the wax tends to adhere to the tip-facing surface 33 of the annular member 31. Moreover, when the tip-facing surface is tapered, the wax tends to wet out and spread outward, and the above-described problems are likely to occur.

  The present invention has been made in view of the above-mentioned problems. An annular part brazed to a tube is formed by externally fitting a hollow bolt member, which is a separate part, from the rear of the tube and screwing it into a screw hole in an attachment target site. In a sensor that can be mounted by pressing a member against an annular seating surface behind a screw hole and securing a seal, among the rear end facing surfaces of the annular member, the annular surface of the surface that forms the pressure receiving surface or the front facing surface An object of the present invention is to provide a sensor manufacturing method including a brazing step effective to suppress or prevent brazing from adhering to a surface pressed against a seat surface.

In order to achieve the above object, according to the first aspect of the present invention, an annular member is externally fitted to a tube, and an outer peripheral surface of the tube and an inner peripheral surface of the annular member are brazed. A sensor having a configuration including a sensor element inside the tip side,
A hollow bolt member is externally fitted to the tube from the rear end side, and the hollow bolt member is screwed into a screw hole in a site to which the sensor is to be attached. In the manufacturing method of the sensor configured to hold the seal by pressing the tip and pressing the tip-facing surface of the annular member against the annular seating surface behind the screw hole,
The annular member before brazing can be inserted into the hollow portion at the front end of the hollow bolt member at a position near the inner peripheral edge of the rear end-facing surface with a clearance fit, and the inner peripheral surface of the annular member Concentric with the ring-shaped or pipe-shaped annular protrusion that protrudes backward,
In brazing the outer peripheral surface of the tube and the inner peripheral surface of the annular member,
The tube with the annular member externally fitted is in a standing state with the tip facing down, and a brazing material is disposed on or applied to the end surface of the projecting end of the annular convex portion on the rear end facing surface or in the vicinity of the end surface. And then brazing by melting the brazing material.

According to a second aspect of the present invention, an annular member is externally fitted to a tube, an outer peripheral surface of the tube and an inner peripheral surface of the annular member are brazed, and a sensor element is provided inside the distal end side of the tube. A sensor having a configuration comprising:
A hollow bolt member is externally fitted to the tube from the rear end side, and the hollow bolt member is screwed into a screw hole in a site to which the sensor is to be attached. In the manufacturing method of the sensor configured to hold the seal by pressing the tip and pressing the tip-facing surface of the annular member against the annular seating surface behind the screw hole,
The annular member before brazing can be inserted into a hole near the inner peripheral edge of the tip-facing surface with a gap fit into a hole forming the inner periphery of the annular seating surface. Concentrically with the inner peripheral surface, a ring-shaped or pipe-shaped annular convex part protruding forward is formed integrally,
In brazing the outer peripheral surface of the tube and the inner peripheral surface of the annular member,
The tube with the annular member externally fitted is in a standing state with the tip facing up, and a brazing material is placed or applied on the end face of the annular projection on the face facing the tip or in the vicinity of the end face. Thereafter, a step of brazing by melting the brazing material is included.

According to a third aspect of the present invention, an annular member is externally fitted to a tube, an outer peripheral surface of the tube and an inner peripheral surface of the annular member are brazed, and a sensor element is provided inside the distal end side of the tube. A sensor having a configuration comprising:
A hollow bolt member is externally fitted to the tube from the rear end side, and the hollow bolt member is screwed into a screw hole in a site to which the sensor is to be attached. In the manufacturing method of the sensor configured to hold the seal by pressing the tip and pressing the tip-facing surface of the annular member against the annular seating surface behind the screw hole,
The annular member before brazing can be inserted into the hollow portion at the front end of the hollow bolt member at a position near the inner peripheral edge of the rear end-facing surface with a clearance fit, and the inner peripheral surface of the annular member A ring-shaped or pipe-shaped annular convex portion that protrudes rearward is formed integrally, and a hole that forms the inner periphery of the annular seating surface at a portion closer to the inner peripheral edge of the tip-facing surface. A ring-shaped or pipe-shaped annular convex part that protrudes forward is formed integrally with the inner peripheral surface of the annular member so that it can enter with a gap fit inside,
In brazing the outer peripheral surface of the tube and the inner peripheral surface of the annular member,
The tube in which the annular member is externally fitted is in an upright state, and the brazing material is located near the end surface of the projecting end of the annular convex portion on the rear end facing surface or the front end facing surface forming the upward surface in that state, or in the vicinity of the end surface. It is characterized by including the process of arrange | positioning or apply | coating and brazing by melting this brazing material after that.

The invention according to claim 4 is characterized in that a chamfered or concave notch is formed along an angle formed by an end surface of the projecting tip of the annular convex portion and an inner peripheral surface. Item 3. The method for manufacturing a sensor according to Item 1 or Item 2.
According to a fifth aspect of the present invention, along an angle formed by an inner peripheral surface and at least one end surface of the projecting end surface of the annular convex portion formed on the rear end facing surface and the front end facing surface. 4. The sensor manufacturing method according to claim 3, wherein a chamfered or concave notch is formed.

According to a sixth aspect of the present invention, the tube has a different-diameter structure having a large-diameter cylindrical portion behind the small-diameter cylindrical portion, and the annular member is fitted with a gap in the small-diameter cylindrical portion. Positioned as a contact state at the tip of the large-diameter cylindrical portion that is a boundary portion of the diameter,
The sensor manufacturing method according to claim 1, wherein the outer peripheral surface of the small-diameter cylindrical portion and the inner peripheral surface of the annular member are brazed. is there.

  According to the first aspect of the invention, the following effects can be obtained. In the present invention, the annular member has the annular convex portion that is concentrically and protrudes rearward in a portion near the inner peripheral edge that is not pressed forward by the hollow bolt member among the rearward facing surfaces. Yes. For this reason, the end surface (hereinafter also simply referred to as “end surface”) of the projecting tip of the annular convex portion is a portion that is pressed forward by the tip of the hollow bolt member during brazing (the rear surface). Among the end-facing surfaces, a surface that receives a pressing force by being pressed against the tip of the hollow bolt member (hereinafter also referred to as a pressure-receiving surface) is higher than the protruding amount. As a result, the end face where the wax is melted is not on the same plane as the pressure receiving face, and is higher than that.

  That is, in the present invention, the wax is melted on the end face of the annular convex portion located higher than the pressure receiving face or in the vicinity of the end face. For this reason, the wax melted at the end face flows into the gap between the inner peripheral surface of the annular member and the outer peripheral surface of the tube and is wetted and spreads by the capillary phenomenon. Since the surface is relatively lower than the end surface, the wax is less likely to get wet, and adhesion of the wax to the surface is prevented.

  In addition, the outer peripheral edge of the end surface has a corner (the angle formed by the end surface and the outer peripheral surface (outer peripheral wall surface) of the annular convex portion). At this corner, the wax is difficult to get wet, and therefore it is difficult to get over this. Even if the wax gets over the corner and wets and spreads on the outer peripheral surface of the annular convex portion, the wetting spread functions to stop at the outer peripheral surface due to the presence of the outer peripheral surface itself. In other words, in the present invention, the corner acts as a dam for suppressing or preventing the molten wax from spreading from the end surface to the outer peripheral surface. In addition, the end surface where the wax is melted is different in height from the pressure receiving surface and is at a high level, and accordingly, the melting surface of the wax and the pressure receiving surface are at the same height (the same surface). Compared to the case, the wetting and spreading path to the pressure receiving surface becomes longer, so that it is possible to obtain the effect of preventing the adhesion of wax to the rear end facing surface forming the pressure receiving surface.

  In the present invention, it is preferable that the projecting amount (the height of the ring or pipe) is set to be large so that the end surface of the annular convex portion is as high as possible from the pressure receiving surface. This is because the larger this is, the higher the height of the outer peripheral surface (outer peripheral wall surface) of the annular convex portion. In other words, the outer peripheral surface of the annular convex portion is a so-called permissible portion (surface) to which wax adheres, and the larger the protrusion amount, the larger the amount can be secured. In addition, by increasing the distance that the wax can reach the pressure receiving surface lower than the end face of the annular convex portion, the risk that the wax adheres to the pressure receiving surface can be further reduced.

  The invention according to claim 2 is brazed in a state in which the tip of the tube stands up. Based on this, the invention according to claim 1 is different from the invention described in claim 1 only in that the annular convex portion is formed so as to protrude on the tip-facing surface of the annular member. That is, in the present invention, the annular convex portion is formed in a portion near the inner peripheral edge that is not pressed against (not pressed against) the annular seat surface, among the surfaces facing the tip, before the brazing. For this reason, the end surface (hereinafter also simply referred to as “end surface”) of the projecting tip of the annular convex portion is a portion (pressing surface to the annular seating surface) that is pressed against the annular seating surface during brazing. (Hereinafter, also referred to as a pressing surface), the amount of protrusion is higher. For this reason, the solder melted at the end face of the annular convex portion flows into the gap between the inner peripheral surface of the annular member and the outer peripheral surface of the tube so as to be drawn by capillary action, spreads, and brazes. In this case, the same effect as in the first aspect of the invention can be obtained. That is, the outer peripheral edge of the end surface has a corner (the angle formed by the end surface and the outer peripheral surface (outer peripheral wall surface) of the annular protrusion), and the pressing surface is higher than the outer peripheral surface of the end surface. This is because it is at a low level and is not at the same height as the molten surface of the wax as in the prior art. As a result, even if the molten wax wets and spreads on the outer peripheral surface of the annular convex portion, it is possible to suppress or prevent the wet wax from spreading or adhering to the pressing surface on the tip-facing surface.

  In the invention described in claim 3, based on the configuration, the same effects as those of the inventions described above can be obtained even if the tube is brazed with either the front end or the rear end thereof facing down. For this reason, there exists an effect that it is excellent in the usability (degree of freedom) of a brazing process. For example, when brazing with the tip of the tube facing down (when the rear end-facing surface of the annular member forms an upward surface), the same effect as that of the invention of claim 1 can be obtained. On the contrary, when brazing with the tip of the tube facing up (when the tip-facing surface of the annular member forms an upward surface), an effect similar to that of the invention of claim 2 can be obtained. Furthermore, in the invention according to claim 3, the following effects are also obtained. Even if the molten solder overflows at the lower end of the gap to be brazed, there will always be an annular projection below. For this reason, it is also possible to suppress or prevent the molten wax from sticking to the pressure-receiving surface or the pressing surface forming the downward surface.

  According to a fourth aspect of the present invention, a chamfered or concave notch is formed along an angle formed by an end surface of the projecting tip of the annular convex portion and an inner peripheral surface. For this reason, when the annular member is externally fitted to the tube in a gap-fitted state before brazing, the end surface and its inner peripheral surface (the outer peripheral surface of the tube) are formed with concave grooves that are recessed along the circumferential direction. Is done. This concave groove can act as a wax pool for the wax melted in the brazing process. Therefore, compared with the case where there is no such groove, in the present invention, the amount of the groove makes it easier for the molten wax to flow into the gap. For this reason, suppression or prevention of wax spreading over the outer peripheral surface (outer peripheral wall surface) beyond the outer peripheral edge (the angle formed by the end surface and the outer peripheral surface (outer peripheral wall surface) of the annular convex portion) at the end surface. The effect to do can be further enhanced. In addition, the said notch part is good also as what is formed in the radial direction whole of the said end surface including the invention of Claim 5, and a part of circumferential direction, or the perimeter. That is, the notch portion may be formed as an inclined surface that inclines in a straight line or a curve from the outer peripheral edge of the end surface of the annular convex portion toward the inner peripheral edge. For example, the end surface may be formed as a tapered surface (a tapered tapered annular surface) that is concave as a whole.

  Further, in the invention according to claim 5, the notch is provided only in one of the annular projections, and a brazing material is disposed on the end surface of the annular projection having the notch. In this case, the same effect as that of the fourth aspect of the invention can be obtained. Furthermore, in the invention according to claim 5, when the notch portions are provided in both of the annular convex portions, the concave groove is also formed at the lower end of the brazed gap. It will be. For this reason, it can be further suppressed or prevented that the molten solder wraps around and adheres to the pressure receiving surface or the pressing surface forming the downward surface.

  In the present invention, the tube constituting the sensor may be a straight tube (for example, a tube (circular tube) having a constant diameter before and after the tube), or a different diameter having a large-diameter cylindrical portion behind the small-diameter cylindrical portion. An appropriate structure such as a structure having a different diameter (for example, a concentric pipe having a different diameter) may be selected and used. In the latter case, when the annular member is positioned using a member having a different diameter structure as in the invention described in claim 6, the positioning becomes easy. In such a case, the following effects can be obtained if the upward surface of the annular member is brazed on the surface of the annular member. By using a tube with a different diameter structure as described above, the rear end facing surface of the annular member is the upward surface, and the tip of the large-diameter cylindrical portion of the inserted tube is brought into contact with the inner peripheral edge of the rear end facing surface. When the positioning is performed, the inner peripheral surface of the annular member is blocked by the tip (tip-facing surface) of the large-diameter cylindrical portion of the tube. For this reason, the flowability of the molten wax into the gap is reduced. On the other hand, when the tip-facing surface of the annular member is an upward surface, positioning by contact can be performed without such a problem.

The longitudinal cross-sectional view which shows an example of the sensor manufactured in this invention, and its principal part enlarged view. It is explanatory drawing of the annular member which comprises the sensor of FIG. 1, A is the perspective view seen from the rear end surface side, B is the top view, C is the center cross-sectional view of B. In the manufacture of the sensor of FIG. 1, it is explanatory drawing of the process of brazing an annular member to a tube, Comprising: The left figure is a longitudinal cross-sectional view which shows before brazing and the right figure after brazing. Sectional drawing for description of the state which attaches the sensor of FIG. 1 to the screw hole of an attachment object site | part, and its principal part enlarged view. FIG. 5 is a further enlarged view of the enlarged view of FIG. 4. It is explanatory drawing which shows another example of an annular member, A is the figure seen from the rear end surface side, B is the figure seen from the outer peripheral surface side. It is explanatory drawing of the process of brazing this annular member to a tube using the annular member of FIG. 6, Comprising: The left figure is a longitudinal cross-sectional view which shows before brazing and the right figure after brazing. Sectional drawing for description of the state which attaches the sensor assembled using the annular member of FIG. 6 to the screw hole of an attachment object site | part, and its principal part enlarged view. It is explanatory drawing which shows another example of an annular member, A is the figure seen from the rear-end surface side, B is the center horizontal half sectional view. It is explanatory drawing of the process of brazing this annular member to a tube using the annular member of FIG. 9, Comprising: The left figure is a longitudinal cross-sectional view which shows before brazing and the right figure after brazing. Sectional drawing for description of the state which attaches the sensor assembled using the annular member of FIG. 9 to the screw hole of an attachment object site | part, and its principal part enlarged view. It is explanatory drawing of the process of brazing an annular member using a straight tube, Comprising: The left figure is a longitudinal cross-sectional view which shows before brazing and the right figure after brazing. This is a conventional sensor that presses an annular member brazed to a tube by externally fitting a hollow bolt member to the tube and screwing it into a screw hole in the attachment target site, and this is applied to the annular seating surface behind the screw hole. The longitudinal cross-sectional view explaining the sensor attached by pressing. In the manufacturing process of the sensor of FIG. 13, it is explanatory drawing of the process of externally fitting an annular member to a tube and brazing, Comprising: The left figure is a longitudinal cross-sectional view which shows before brazing and the right figure after brazing.

  The embodiment of the present invention (first embodiment) will be described in detail with reference to the drawings. Before that, the configuration of the sensor manufactured by the present manufacturing method will be described based on FIG. 1 and FIG. explain. In FIG. 1, reference numeral 101 denotes a sensor, and a metal (for example, SUS) tube 11 with a distal end (lower end in FIG. 1) 12 closed, and a distal end 12 of the tube 11 or a portion near the distal end. The sensor element 21 and the like are arranged. The tube 11 in which the sensor element 21 is arranged is inserted into an annular member 31 made of, for example, SUS having an annular shape (cylindrical shape), and is brazed to the inner peripheral surface 32a. In addition, the tube 11 of this example is set as the thing of the concentric different diameter formed by expanding in multiple steps toward the back from the front-end | tip 12. FIG. Details of the tube 11 will be described later. Further, in this example, the tube 11 is inserted into the tube insertion hole 32 inside the annular member 31 with a gap fit, with the second straight pipe portion 15 located closer to the tip than the middle. The inner peripheral surface 32 a and the outer peripheral surface 15 a of the second straight pipe portion 15 of the tube 11 are brazed with, for example, a copper solder 230. Accordingly, the annular member 31 forms a circular flange fixed to the outer peripheral surface of the tube 11.

  As shown in FIG. 2, the annular member 31 used for manufacturing the sensor 101 includes a short cylindrical annular member main body 34 and a flat circular ring that forms an upward surface of the annular member main body 34 in FIG. The rear end-facing surface 35 includes a ring (annular) -shaped (or pipe (circular) -shaped) annular convex portion 36 that protrudes rearward and concentrically with the inner peripheral surface 32a. The rear end facing surface 35 forms a plane perpendicular to the axis (G in FIG. 1). On the other hand, the annular protrusion 36 protrudes vertically at the rear end-facing surface 35 vertically by a predetermined height (H1) (see FIG. 2). In this example, the protruding end surface 36a forms a plane perpendicular to the axis G, and the radial width is constant along the circumferential direction. The inner diameter of the annular protrusion 36 is the same as the inner diameter of the inner peripheral surface 32 a of the annular member main body 34. In addition, the outer diameter D1 of the annular convex part 36 is set smaller than the inner diameter D2 of the hollow bolt member 301 mentioned later (refer FIG. 4). Thereby, the annular convex part 36 is formed so as to enter into the hollow part with a gap fit when the rear end facing surface 35 of the annular member 31 is pressed by a hollow bolt member 301 described later. That is, when the sensor 101 is mounted by screwing the hollow bolt member 301, the tip 305 of the hollow bolt member 301 is formed so as to press the rear end facing surface 35 outward from the outer peripheral surface 36 b of the annular convex portion 36. . Further, the tip-facing surface 33 that is the downward surface of FIG. 1 of the annular member 31 is a tapered surface that tapers, except for the flat annular portion 30 near the inner peripheral surface 32a. Incidentally, the flat annular portion 30 does not contribute to the seal in mounting the sensor 101 of this example.

  Next, the tube 11 will be described. In this example, as shown in FIG. 1 and the like, the tube 11 is formed in a concentric / different-diameter cylindrical shape having a large diameter sequentially from the closed front end 12 toward the rear end (upper end in FIG. 1) 19. Yes. Specifically, the portion near the tip 12 forms an element accommodating portion 13 that forms a cylinder with the smallest outer diameter, and the first straight pipe portion 14 having a larger diameter is formed in the rear (upper direction in the drawing) following this. ing. Further, a second straight pipe portion 15 having a larger diameter is provided behind the first straight pipe portion 14. As described above, in this example, the second straight pipe portion 15 is inserted into the tube insertion hole 32 of the annular member 31, and the minute inner surface 32 a and the outer peripheral surface 15 a of the second straight pipe portion 15 are minute. The gap is configured to form a small-diameter cylindrical portion to be brazed. Hereinafter, the second straight pipe portion 15 is referred to as a small diameter cylindrical portion 15.

  A tube insertion hole 32 and a cylindrical large-diameter tube portion 17 having a larger diameter than the small-diameter tube portion 15 are provided behind the small-diameter tube portion 15 (part near the rear end of the tube 11). ing. As described above, in this example, the tube 11 is sequentially moved from the front end 12 toward the rear end 19 with the element accommodating portion 13, the first straight pipe portion 14, the small diameter cylindrical portion 15, and the large diameter cylindrical portion 17, Concentric and large diameter cylindrical tubes are formed. Note that the tip 16 of the large-diameter cylindrical portion 17 that is a boundary portion between the small-diameter cylindrical portion 15 and the large-diameter cylindrical portion 17 at the rear thereof is a tapered taper (a tapered shape with an angle with respect to the axis G of 45-60. A tip-facing surface (annular surface) 16 having an annular shape with a degree taper) is formed.

  In such a tube 11, a sensor element (thermosensitive element) 21 made of a thermistor sintered body sealed with glass 24 is disposed in the element accommodating portion 13 at the tip end 12. The insulator tube 41 is arranged in such a manner as to extend forward and backward through the element support 22 that supports the sensor element 21. The insulator tube 41 is a cylindrical tube made of ceramic and having a constant cross section having two holes formed in the inside thereof along the axis G so as to penetrate therethrough. The insulator tube 41 passes through a conductive wire including two electrode wires 23 extending rearward from the element 21 and a core wire 25 connected thereto.

  Further, a rear end 26 of the core wire 25 is projected from a rear end 45 of the insulator tube 41, and a terminal fitting 28 is fixed to the rear end 26 by welding. A tip 53 of a lead wire (electric signal extracting wire) 51 with a resin coating layer is connected to the crimp terminal portion 29 of the terminal fitting 28 by crimping. The lead wire 51 is led out (rearward, upper side in FIG. 1) from a rear end 72 of a seal member 71 provided in a portion near the rear end 19 of the tube 11. That is, the lead wire 51 passes through the through-hole 77 in the sealing member 71 having a cylindrical shape made of rubber (made of heat-resistant rubber) disposed in the large-diameter cylindrical portion 17 near the rear end of the tube 11. Has been.

  On the other hand, between the rear end 45 of the insulator tube 41 and the front end 73 of the seal member 71 in the drawing, a part of the terminal fitting 28 connected to the front end 53 of each lead wire 51 and the rear end 26 of the core wire 25. A pipe 50 made of a heat-resistant hard resin (for example, made of PTFE) that surrounds a portion including a shift portion is disposed in a compressed state between the front and rear. As a result, electrical insulation between the lead wires 51 in the meantime is ensured. The insulator tube 41 is held in a pressed (compressed) state. This forward pressing is performed by loading the sealing member 71 into a predetermined position in the large-diameter cylindrical portion 17 on the rear end 19 side of the tube 11 and then crimping and compressing the rear end portion 17c to a reduced diameter. At the same time as holding the seal in the rear end 17c. That is, utilizing the extension deformation in the front-rear direction based on the compression in the radial direction of the seal member 71 by the caulking, the insulator tube 41, the element support body 22, The sensor element 21 sealed with the glass 24 is pressed toward the inner surface of the distal end 12 of the tube 11.

  Thus, such a sensor 101 incorporates each component so as to have the above-described configuration in the tube 11 that is externally fitted with the annular member 31 and brazed, and is disposed in a portion near the rear end of the tube 11. The lead wire 51 is pulled out from the sealed member 71 and the rear end portion 17c is crimped to obtain a finished product.

  Now, during the manufacturing process of the sensor 101, the main part of the present invention (manufacturing method) in which the tube 11 is inserted into the annular member 31 which is a component before brazing (see FIG. 2) and brazed. An example (first embodiment) embodying the brazing process will be described in detail. As shown in the left diagram of FIG. 3, the tube 11 is inserted into the inner peripheral surface 32 a of the annular member 31 from the rear end facing surface 35 side. Then, the tube 11 is held in an upright state with the rearward facing surface 35 being an upward surface. For example, as shown in the left diagram of FIG. 3, the annular member 31 is supported by a support jig 211 installed on the support base surface 201, and the tube 11 is inserted to stand vertically with its tip 12 down. . At this time, the distal end 12 of the tube 11 may be brought into contact with the support base surface 201 as shown, or may be separated. It should be noted that the distal-facing surface 16 of the large-diameter cylindrical portion 17 of the tube 11 may be positioned so as to abut against the inner peripheral edge of the end surface 36a of the annular convex portion 36 of the annular member 31, or may be spaced apart. May be. The height of the support jig 211 may be set so as to support the downward surface of the annular member 31 corresponding to these.

  Next, a predetermined amount of brazing material 220 is disposed on the end surface 36a of the annular convex portion 36 in the annular member 31 that is externally fitted to the tube 11 standing in this way, or in the vicinity thereof. In this example, it is a copper brazing and forms a wire or a ring, and is arranged so as to surround the tube 11. In the case of a paste such as Ni solder, a predetermined amount may be applied to the same part. Then, for example, it is heated to a brazing temperature for a predetermined time in a vacuum furnace. By doing so, the brazing material 220 is melted on the end face 36 a of the projecting tip of the annular convex portion 36. At the same time, the molten wax flows into the gap between the inner peripheral surface 32a of the annular member 1 and the outer peripheral surface 15a of the small-diameter cylindrical portion 15 of the tube 11 so as to be drawn by capillary action and spreads. Thus, after cooling and solidification, the outer peripheral surface is brazed with the copper solder 230 (see the right figure in FIG. 3).

  In the brazing process, since there is a corner on the outer peripheral edge of the end surface 36a of the projecting tip of the annular convex portion 36, the molten brazing hardly spreads over the outer peripheral surface 36b of the annular convex portion 36 beyond this corner. Further, the rear end facing surface 35 forming the pressure receiving surface is lower than the end surface 36a by the height H1 of the outer peripheral surface 36b. That is, unlike the conventional case, the melting surface and the pressure receiving surface of the wax are not on the same surface. For this reason, even if the wax wets and spreads from the end surface 36a of the annular convex portion 36 to the outer peripheral surface 36b, wetting and spreading to the rear end facing surface 35 forming the pressure receiving surface is suppressed or prevented. The adhesion of wax to 35 is suppressed or prevented. Even if the melted wax passes over the outer peripheral edge (corner) of the end surface 36a, spreads on the outer peripheral surface (outer peripheral wall surface) 36b, and adheres to the outer peripheral surface (outer peripheral wall surface) 36b, the problem due to the fact is that Absent. A sensor (finished product) is obtained by incorporating each part into the tube 11 (tube 11 with the annular member 31) after the brazing process, as in the above-described configuration. As shown in FIG. 4, the obtained sensor has a hollow bolt member 301, which is a separate part, fitted on the tube 11 constituting the sensor 101, and a mounting target site (shown by a two-dot chain line in FIG. 4) 500. This is because the screw hole 510 is screwed with a predetermined torque and attached, but the attachment of the wax to the outer peripheral surface 36b does not affect the attachment.

  That is, in mounting the sensor 101 in such a manner, the tip-facing surface 33 of the annular member 31 forming the sensor 101 is applied to the annular seating surface 520 that forms a tapered taper at the back of the screw hole 510, and the tube The hollow bolt member 301 that is externally fitted to 11 is brought into the screw hole 510 and screwed with a predetermined torque. As a result, the rear end facing surface 35 of the annular member 31 is pushed forward at the front end 305 of the hollow bolt member 301. Then, the tip-facing surface 33 is pressed against the annular seating surface 520 at the back of the screw hole 510 and the attachment is performed. In such attachment, even if wax adheres to the outer peripheral surface (outer peripheral wall surface) 36 b of the annular convex portion 36 of the sensor 101 of this example, the annular convex portion 36 including the outer peripheral surface 36 b is not attached to the hollow bolt member 301. The dimensional relationship (D2-D1) is set so as to be able to enter the hollow portion 310 of the tip 305 with a clearance fit. On the other hand, no wax adheres to the rear end-facing surface 35 of the annular member 31 that forms the pressure receiving surface pressed by the hollow bolt member 301. For this reason, in the installation by screwing into the screw hole 510, there is no problem of insufficient pressing force due to adhesion soldering or uneven pressing force.

  As described above, the hollow bolt member 301 has an inner diameter D2 of the hollow portion (circular hole) 310 larger than the outer diameter of the large-diameter cylindrical portion 17 of the tube 11, and the outer diameter (outer peripheral surface) of the annular convex portion 36. It is set larger than the outer diameter D1 in 36b. As a result, even if a wax is attached to the outer peripheral surface (outer peripheral wall surface) 36b of the annular convex portion 36, the screwing is hindered unless the wax is thick enough to interfere with the hollow bolt member 301. This is because there is not. That is, the outer peripheral surface (outer peripheral wall surface) 36b is an allowable portion (surface) for adhesion of wax. For this reason, it is suppressed or prevented that wax adheres to the rear end facing surface 35 of the annular member 31 that forms the pressure receiving surface. As understood from this, (D2-D1) may be set so as to ensure a gap fit according to the film thickness of the attached wax. Further, the height H1 of the outer peripheral surface (outer peripheral wall surface) 36b of the annular convex portion 36 is preferably set as large as possible. As described above, this is because the higher this is, the lower the risk that the wax will adhere to the rear end-facing surface 35 that forms a pressure receiving surface lower than the end surface 36 a of the annular convex portion 36. As shown in FIG. 4, in this example, a round chamfer 315 is attached along the circumferential direction at an angle 315 formed between the tip (surface) 305 of the hollow bolt member 301 and the inner peripheral surface of the hollow portion 310. It has been. In addition, a polygonal portion (tool engaging portion) 334 for screwing having a diameter larger than that of the screw 333 of the outer peripheral surface 330 is provided at the rear end (illustrated upper end) of the hollow bolt member 301.

  In the annular member 31 of the above example, as shown in FIG. 5, a notch portion 37 is formed along the angle formed by the projecting end surface 36a of the annular convex portion 36 and the inner peripheral surface 32a. It is good to keep. When the notch portion 37 is formed in this way, when this is brazed, a concave groove recessed along the circumferential direction is formed in a portion closer to the outer peripheral surface 15a of the tube 11 on the end surface 36a forming the upward surface. For this reason, the solder melted at the end surface 36 a in the brazing process enters the concave groove formed by the notch portion 37 and flows into the gap between the outer peripheral surface 15 a of the small diameter cylindrical portion 15 and the inner peripheral surface 32 a of the annular member 31. be able to. That is, since the notched portion 37 is formed, the concave groove forms a wax pool, and accordingly, compared with the case without this, the molten brazing exceeds the outer peripheral edge corner of the end face 36a. This is because an action of suppressing the wet spread on the surface 36b is obtained. In addition, although the notch part 37 has shown the chamfering thing in FIG. 5, as shown with the broken line, it is good also as a circular arc or a L-shaped concave shape. Further, as indicated by a broken line in the enlarged view of FIG. 5, a straight line or a curved line from the outer peripheral edge 36 c of the end surface 36 a of the annular convex portion 36 toward the inner peripheral edge, that is, in the entire radial direction of the end surface 36 a. It may be formed as an inclined surface inclined downward.

  Next, another example (second embodiment) that embodies the brazing process that forms the main part of the manufacturing method of the present invention will be described with reference to FIGS. However, in this example, only the annular member 231 is different from the above example regarding the constituent members. That is, in the annular member 231 of this example, on the contrary to the above example, the rearward facing surface 35 is a simple plane perpendicular to the axis G, and the annular convex portion is formed on the inner peripheral edge portion of the distal end facing surface 33. 38 is formed so as to protrude toward the tip (see FIG. 6). Based on such a difference in the annular member 231, the brazing in the manufacturing method of this example is different from the above example in that brazing is performed with the tip 12 of the tube 11 facing up, contrary to the above example. For this reason, it demonstrates centering on the difference, and it attaches | subjects the same code | symbol about the same technical content, and abbreviate | omits the description suitably. The same shall apply hereinafter.

  That is, in this example, as shown in FIG. 6, the annular member 231 has a ring shape that is concentric with the inner peripheral surface 32 a on the tip-facing surface 33 and protrudes by a predetermined amount H2 toward the tip (downward in FIG. 6B). Alternatively, a pipe-like annular convex portion 38 is integrally formed. As shown in FIG. 8, the annular convex portion 38 has an outer diameter D <b> 3 in a hole 530 that is continuous with the inner periphery of the annular seating surface 520 behind the screw hole 510 in the attachment target portion 500 of the sensor 101. It is set to be smaller than the inner diameter D4 of the hole 530 so as to be able to enter with a gap fit.

  In this example, as shown in FIG. 7, the tube 11 is vertically set up by the guide jig 221 installed on the support base surface 201 so that the tip 12 thereof is positioned upward (see the left figure of FIG. 7). ). Next, the annular member 231 is fitted on the small diameter cylindrical portion 15 of the tube 11 from the distal end 12 side so that the distal end facing surface 33 becomes an upward surface. Thereby, the rear end facing surface 35 of the annular member 231 is a downward facing surface, and the portion near the inner peripheral edge of the rear end facing surface 35 is supported by the tip 16 of the large-diameter cylindrical portion 17 of the tube 11. If necessary, the annular member 231 may be separately supported by a separate support jig 231 so that the inclination with respect to the tube 11 is prevented.

  Next, a predetermined amount of brazing material 220 is arranged on or around the annular convex portion 38 projecting upward as shown in FIG. 7 in the annular member 231 fitted on the tube 11 standing in this way. Or apply. Then, as in the above example, the brazing material 220 is melted by heating to a brazing temperature for a predetermined time. Thus, the molten wax flows into the gap between the outer peripheral surface 15a of the small-diameter cylindrical portion 15 of the tube 11 and the inner peripheral surface 32a of the annular member 231, and spreads wet. Thus, after the cooling and solidification, the outer peripheral surface is brazed with the solder 230 (see the right figure in FIG. 7).

  Thus, in this example, substantially the same effect as the above example can be obtained. In other words, in this example, the annular convex portion 38 is formed in a portion near the inner peripheral edge that is not pressed against the annular seat surface 520 in the tip-facing surface 33 before brazing. The end surface 38a of the projecting tip of the annular convex portion 38 is higher than the tip-facing surface 33 (pressing surface) to be pressed against the annular seating surface 520 at the time of brazing by the amount of protrusion H2. . For this reason, the wax melted at the end surface 38 a of the annular convex portion 38 flows into the gap between the inner peripheral surface 32 a of the annular member 231 and the outer peripheral surface 15 a of the small diameter cylindrical portion 15 of the tube 11, while the annular convex portion 38. It is difficult for the outer peripheral surface (outer peripheral wall surface) 38b to wet and spread beyond the outer peripheral edge (corner) of the end surface 38a of the protrusion. Further, even if wetting and spreading beyond the outer peripheral edge (corner) of the end surface 38a, it is possible to suppress or prevent wetting and spreading to the tip-facing surface 33 (pressing surface). Even if the wax spreads and adheres to the outer peripheral surface 38 b of the annular convex portion 38, the outer peripheral surface 38 b is a gap fit in the hole 530 that continues to the inner periphery of the annular seat surface 520 at the back of the screw hole 510. It is about to enter (see FIG. 8). For this reason, the adhesion solder does not affect the screwing by the hollow bolt member 301.

  Even in the case where the tube 11 is brazed so that the distal end 12 is positioned upward as in this example, as shown by the broken line in the enlarged view of FIG. A notch 39 may be formed along the inner periphery at an angle formed by the end surface 38a of the portion 38. This is because, as described above, the same effect as that obtained by providing the notched portion on the end surface 36a of the annular convex portion 36 formed on the rear end facing surface 35 can be obtained.

  Next, a method for brazing using the annular member 331 shown in FIG. 9 will be described. However, this annular member 331 was used in the first embodiment example and the second embodiment example on the inner peripheral edge portion of the rear end facing surface 35 and the inner peripheral edge portion of the front end facing surface, respectively. The same annular convex portions 36 and 38 as in the annular members 31 and 231 are integrally formed. In the annular member 331 shown in FIG. 9, notches 37 and 39 are formed at the angles formed by the end surfaces 36a and 38a and the inner peripheral surface 32a of both the upper and lower annular convex portions 36 and 38. It is supposed to be.

  Thus, in the case of using such an annular member 331, the tube 11 can achieve the same effects as the above examples even if the tube 12 is brazed with either the front end 12 or the rear end thereof facing down. it is obvious. For this reason, there exists an effect that it is excellent in the freedom degree of a brazing process. For example, as shown in FIG. 10, when the tube 11 is brazed with the tip 12 down (when the rear end-facing surface 35 of the annular member 331 forms an upward surface), it is the same as in the first embodiment. The effect is obtained. Moreover, since the annular protrusions 36 and 38 are formed on both the upper and lower sides as described above, the following effects are also obtained. This is because even if the amount of the brazing material 220 is large and overflows at the lower end of the gap to be brazed, there is an annular convex portion 38 on the downward surface. That is, as apparent from FIG. 10, the presence of such an annular convex portion 38 can effectively prevent the molten solder from flowing around and adhering to the tip-facing surface 33 that forms the downward surface. . In particular, in this example, since the cutout portions 37 and 39 are provided at the angles formed by the end surfaces 36a and 38a and the inner peripheral surface 32a of the upper and lower annular convex portions 36 and 38, the tube 11 Even if brazing is performed with either end facing up, the brazing is difficult to spread on the outer peripheral surfaces 36b, 38b of the annular projections 36, 38. However, in the present invention, such a notch is not essential. On the other hand, it can be said that it is preferable to provide a notch in the annular convex portion (annular convex portion 36 in FIG. 10) to be positioned because a pool of melted wax can be secured.

  FIG. 11 shows a sensor 101 using such an annular member 331, and using this, the hollow bolt member 301 is externally fitted to the tube 11 in the same manner as in each of the above examples, and the screw of the attachment target site 500 is shown. A state in which the holes 510 are screwed into the holes is shown. In this example, since the annular protrusions 36 and 38 are provided above and below, the clamping force is received by the tip facing surface (tapered surface) 33 pressed against the annular seating surface 520 and the tip 305 of the hollow bolt member 301. It is possible to suppress or prevent the wax from adhering to both the rear end facing surfaces 35. As a result, it is possible to more reliably solve the problem of the sealing performance in the mounting of the sensor 101 based on the adhesion wax.

  In addition, it is clear that brazing can be performed with the tip 12 of the tube 11 facing upward even when brazing using the annular member 331 shown in FIG. The same effect as in can be obtained. In this case, it is assumed that the end surface 36a of the annular convex portion 36 formed to project from the rear end-facing surface 35 is in contact with and supported by the distal end surface 16 of the large-diameter cylindrical portion 17 of the tube 11. preferable.

  In the above example, the tube 11 is embodied in the manufacturing method of the sensor having a different diameter structure having the large-diameter cylindrical portion 17 behind the small-diameter cylindrical portion 15 on the distal end side. However, the tube 11 is manufactured in the manufacturing method of the present invention. The tube forming the sensor to be used is not limited to this. For example, when the tube 11 having the same diameter is used later as shown in FIG. 12, the present invention can be similarly applied to the step of brazing the annular member 331 to the tube 11. FIG. 12 illustrates the case where the tube 11 is brazed using the annular member 331 used in the previous example with the tip 12 of the tube 11 facing down, but the present invention can be similarly applied to any of the previous and subsequent cases. Even when such a tube is used, the cutout portion of the annular member 331 may not be provided, or may be provided only on the annular convex portion positioned above.

  The present invention is not limited to the examples described above, and can be embodied with appropriate modifications without departing from the gist of the present invention. For example, the annular member to be used can be applied even if the tip-facing surface is a flat surface having no taper, and the same effect can be obtained. The sensor of the present invention is not limited to the one for measuring the temperature of exhaust gas, and can be widely applied to sensors used for other purposes.

DESCRIPTION OF SYMBOLS 11 Tube 12 Tube front-end | tip 15a Outer peripheral surface 15 of a tube (small-diameter cylindrical part) 15 Small-diameter cylindrical part 16 of a tube The front-end | tip (front-facing surface) of a large diameter cylindrical part
17 Large-diameter cylindrical portion of tube 19 Rear end 21 of tube Sensor elements 31, 231, 331 Annular member 32 a Inner circumferential surface 33 of annular member (tube insertion hole) Front end facing surface 35 of annular member Rear end facing surface 36 of annular member , 38 Annular projections 36a, 38a End surfaces 37, 39 of the projections of the annular projections Notch 101 Sensor 220 Brazing material 301 Hollow bolt member 305 Hollow bolt member tip 310 Hollow bolt member hollow portion 500 Sensor mounting target site 510 Screw hole 520 Annular seating surface 530 behind the screw hole An air hole forming the inner periphery of the annular seating surface

Claims (6)

An annular member is externally fitted to a tube, the outer peripheral surface of the tube and the inner peripheral surface of the annular member are brazed, and the sensor has a configuration in which a sensor element is provided inside the distal end side of the tube. And
A hollow bolt member is externally fitted to the tube from the rear end side, and the hollow bolt member is screwed into a screw hole in a site to which the sensor is to be attached. In the manufacturing method of the sensor configured to hold the seal by pressing the tip and pressing the tip-facing surface of the annular member against the annular seating surface behind the screw hole,
The annular member before brazing can be inserted into the hollow portion at the front end of the hollow bolt member at a position near the inner peripheral edge of the rear end-facing surface with a clearance fit, and the inner peripheral surface of the annular member Concentric with the ring-shaped or pipe-shaped annular protrusion that protrudes backward,
In brazing the outer peripheral surface of the tube and the inner peripheral surface of the annular member,
The tube with the annular member externally fitted is in a standing state with the tip facing down, and a brazing material is disposed on or applied to the end surface of the projecting end of the annular convex portion on the rear end facing surface or in the vicinity of the end surface. A method for manufacturing a sensor, further comprising a step of brazing by melting the brazing material. An annular member is externally fitted to a tube, the outer peripheral surface of the tube and the inner peripheral surface of the annular member are brazed, and the sensor has a configuration in which a sensor element is provided inside the distal end side of the tube. And
A hollow bolt member is externally fitted to the tube from the rear end side, and the hollow bolt member is screwed into a screw hole in a site to which the sensor is to be attached. In the manufacturing method of the sensor configured to hold the seal by pressing the tip and pressing the tip-facing surface of the annular member against the annular seating surface behind the screw hole,
The annular member before brazing can be inserted into a hole near the inner peripheral edge of the tip-facing surface with a gap fit into a hole forming the inner periphery of the annular seating surface. Concentrically with the inner peripheral surface, a ring-shaped or pipe-shaped annular convex part protruding forward is formed integrally,
In brazing the outer peripheral surface of the tube and the inner peripheral surface of the annular member,
The tube with the annular member externally fitted is in a standing state with the tip facing up, and a brazing material is placed or applied on the end face of the annular projection on the face facing the tip or in the vicinity of the end face. Then, a method for manufacturing a sensor, comprising: a step of brazing by melting the brazing material. An annular member is externally fitted to a tube, the outer peripheral surface of the tube and the inner peripheral surface of the annular member are brazed, and the sensor has a configuration in which a sensor element is provided inside the distal end side of the tube. And
A hollow bolt member is externally fitted to the tube from the rear end side, and the hollow bolt member is screwed into a screw hole in a site to which the sensor is to be attached. In the manufacturing method of the sensor configured to hold the seal by pressing the tip and pressing the tip-facing surface of the annular member against the annular seating surface behind the screw hole,
The annular member before brazing can be inserted into the hollow portion at the front end of the hollow bolt member at a position near the inner peripheral edge of the rear end-facing surface with a clearance fit, and the inner peripheral surface of the annular member A ring-shaped or pipe-shaped annular convex portion that protrudes rearward is formed integrally, and a hole that forms the inner periphery of the annular seating surface at a portion closer to the inner peripheral edge of the tip-facing surface. A ring-shaped or pipe-shaped annular convex part that protrudes forward is formed integrally with the inner peripheral surface of the annular member so that it can enter with a gap fit inside,
In brazing the outer peripheral surface of the tube and the inner peripheral surface of the annular member,
The tube in which the annular member is externally fitted is in an upright state, and the brazing material is located near the end surface of the projecting end of the annular convex portion on the rear end facing surface or the front end facing surface forming the upward surface in that state, or in the vicinity of the end surface. A method for manufacturing a sensor, comprising the steps of: placing or coating the substrate, and then brazing by melting the brazing material.   The chamfered or concave cutout is formed along an angle formed by an end surface of the projecting tip of the annular convex portion and an inner peripheral surface. A method for producing the sensor according to item.   A chamfered or concave notch is formed along an angle formed by an inner peripheral surface of at least one end surface of the projecting tip of the annular convex portion formed on the rear end surface and the front end surface. The method of manufacturing a sensor according to claim 3, wherein a portion is formed. The tube has a different-diameter structure having a large-diameter cylindrical portion behind the small-diameter cylindrical portion, and the annular member is a gap fit in the small-diameter cylindrical portion, and is a boundary portion having a different diameter. It is positioned in contact with the tip of the diameter tube,
The sensor manufacturing method according to claim 1, wherein the outer peripheral surface of the small-diameter cylindrical portion and the inner peripheral surface of the annular member are brazed.

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