JP5718842B2 - Sensor and manufacturing method thereof - Google Patents

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. The present invention relates to a suitable sensor and a method for manufacturing the same.

  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.

  Among these, like the sensor 100 shown in FIG. 10, 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, the tip-facing surface 33 of the annular member 31 fixed to the tube 11 is strongly pressure-bonded (adhered by metal contact) to the seat surface 520 at the back of the screw hole 510 by screwing with the hollow bolt member 301 which is a separate part. The seal is secured and attached. 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. In addition, the seat surface 520 at the back of the screw hole 510 is often a tapered tapered seat surface as shown in FIG. 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. 11, 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. 11, the molten solder 230 partially flows out from the rear end of the upper end of the gap shown in the figure, 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, and is a separate part in mounting the sensor itself, such as a sensor having a brazing structure in which an annular member as described above is brazed to a tube. In the sensor that can be attached by securing the seal by pressing the annular member against the seating surface at the back of the screw hole by fitting the hollow bolt member from the rear of the tube and screwing it into the screw hole in the attachment target site, A sensor having a structure effective for suppressing or preventing brazing from adhering to a rear end-facing surface or a front-facing surface, and a brazing step effective for obtaining such a sensor. It is to provide a manufacturing method.

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 attached, so that the rear end-facing surface of the annular member faces forward with the hollow bolt member. In the sensor configured to press and hold the seal by attaching the tip-facing surface of the annular member to the seating surface at the back of the screw hole,
Before the brazing, the annular member has at least an angle formed by the inner peripheral surface and the rear end facing surface among the angles formed by the inner peripheral surface, the front end facing surface, and the rear end facing surface. While a chamfered or concave notch is formed along the inner circumference ,
The hollow bolt member has an end on the inner peripheral surface of the hollow portion formed outside the outer peripheral end of the notch portion formed at an angle formed by the inner peripheral surface of the annular member and the surface facing the rear end. It is set to be positioned, and at the angle formed by the tip of the hollow bolt member and the inner peripheral surface of the hollow portion, a rounded chamfer is attached along the circumferential direction,
After brazing, a part of the wax accumulates in the notch and is solidified.

According to a second aspect of the present invention, in the first aspect, the notch portion is formed at both an inner peripheral surface of the annular member and an angle formed by a front end facing surface and a rear end facing surface. It is a sensor.
According to a third 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 has a gap fit in the small-diameter cylindrical portion. It is positioned as being in contact with or close to the tip of the large-diameter cylindrical portion that is a boundary portion of the diameter, and the outer peripheral surface of the small-diameter cylindrical portion and the inner peripheral surface of the annular member are brazed. The sensor according to any one of claims 1 and 2.
Invention of Claim 4 is formed so that the said notch part may continue in the circumferential direction along the inner periphery of a cyclic | annular member, It is any one of Claims 1-3 characterized by the above-mentioned. Sensor.

In the invention of claim 5, when 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 set in a standing state, and in the state, a solder is placed in or near the notch in the front-facing surface or the rear-facing surface forming the upward surface of the annular member. The method for manufacturing a sensor according to any one of claims 1 to 4, further comprising a step of placing or applying a material, and then brazing the material by melting the brazing material. is there.
In the invention of claim 6, when 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 a brazing material is disposed or applied in or near the notch portion in the tip-facing surface that forms the upward surface of the annular member in that state. The method for manufacturing a sensor according to claim 3, further comprising a step of brazing by melting the brazing material.

  In the invention according to claim 1, based on the configuration, in performing the brazing, the tube with the annular member fitted externally is in a standing state, and the tip-facing surface that forms the upward surface of the annular member in that state Alternatively, brazing can be performed by placing or applying a brazing material in or near the notch on the rear end facing surface, and then melting the brazing material. That is, since the sensor according to claim 1 can be manufactured by the manufacturing method according to claim 5, the following effects can be obtained.

  In such a brazing process, the molten braze flows into the gap between the outer peripheral surface of the tube and the inner peripheral surface of the annular member by capillary action, spreads out, and brazes between the outer peripheral surfaces. On the other hand, in the present invention, since the notch portion as described above is formed, before the brazing, when the annular member is externally fitted to the tube in a gap fitting state, the tip-facing surface or the rear surface that forms an upward surface A concave groove that is recessed along the circumferential direction is formed in a portion near the outer peripheral surface of the tube on the end-facing surface. This concave groove can act as a wax reservoir in which molten wax accumulates in the brazing process. For this reason, compared with the case where there is no such a groove, in the brazing step, the amount of the groove is so high that the molten solder is less likely to spread on the front-facing surface or the rear-facing surface forming the upward surface. . In other words, in the present invention, the presence of the concave groove formed by the notch portion can provide the effect of suppressing or preventing the adhesion of wax to the front-facing surface or the rear-facing surface forming the upward surface.

  As a result, after being assembled as a sensor after brazing, a hollow bolt member, which is a separate part, is externally fitted from the rear of the tube and screwed into the screw hole at the attachment target site with a predetermined torque, and the annular member is screwed into the screw hole. Stable sealing performance is maintained even when the seal is secured and attached to the seating surface behind. Note that the tube may be brazed with either its front end or rear end down, and in the case of brazing with its front end down, the annular member has a rear end facing surface as an upward surface. Therefore, the notch is formed along the inner periphery at an angle formed by the inner peripheral surface of the annular member and the surface facing the rear end. And vice versa.

  In the invention described in claim 2, in addition to the effect of the invention described in claim 1, the following effect is obtained. In the present invention, the notch is formed on both sides as described above. For this reason, before brazing, when the annular member is externally fitted to the tube in a gap-fitting state, it is also circumferentially disposed on a portion closer to the outer peripheral surface of the tube on the front-facing surface or the rear-facing surface forming a downward surface. A concave groove is formed that is recessed along. On the other hand, the molten solder in the brazing step flows into the gap between the outer peripheral surface of the tube and the inner peripheral surface of the annular member by capillary action from the upper end to the lower end of the gap and spreads. At this time, even if there is an excessive molten wax and it is overflowing at the lower end of the gap, in the present invention, there is a groove by the notch at the lower end position, which acts as a wax pool. Can be made.

  That is, when the sensor according to the second aspect of the present invention is manufactured by the manufacturing method according to the fifth aspect of the present invention, there is a concave groove in a portion closer to the outer peripheral surface of the tube even on the downward surface of the annular member. Become. For this reason, compared with the case where there is no such a groove, it is more difficult for the molten wax to wrap around the tip-facing surface or the rear-facing surface that forms a downward surface, and to spread wet. It will be a thing. For this reason, it is possible to obtain the effect of suppressing or preventing the adhesion of wax on both the front end surface and the rear end surface. Therefore, after being assembled as a sensor after brazing, a hollow bolt member, which is a separate part, is externally fitted from the rear of the tube and screwed into a screw hole at a site to be attached with a predetermined torque, and the annular member is fitted into the screw hole. When pressing the back seating surface to secure and attach the seal, a more stable sealing performance is maintained.

  When the sensor according to claim 1 or 2 is brazed in the brazing step in the manufacturing method according to claim 5, among the annular members, the upward surface is the tip-facing surface or the Any of the rear end facing surfaces may be used. That is, the tube may be erected with either its front end or rear end facing down. On the other hand, the tube is of 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. In some cases, the large-diameter cylindrical portion is positioned so as to be in contact with or close to the tip, and the outer peripheral surface of the small-diameter cylindrical portion and the inner peripheral surface of the annular member are brazed. That is, a sensor having the configuration according to claim 3. In this case, since the tip of the large-diameter cylindrical portion can be used as a positioning reference, it is easy to set up in brazing and simplify the support jig, which is convenient. On the other hand, in such a case, as in the invention described in claim 6, it is preferable that the upward surface of the annular member is formed by the tip-facing surface. In other words, it is preferable to braze the tube with the tip end upright. The reason is as follows.

  In the case of 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 the inner peripheral edge (notch portion) of the rear end facing surface. If it makes contact or approach, the notch will be covered with the tip (tip-facing surface) of the large-diameter cylindrical portion of the tube. That is, depending on the shape and structure of the notch, for example, in the case of a notch having the same cross section along the circumferential direction, the upper end of the gap between the annular member and the inner and outer peripheral surfaces of the tube Become. Accordingly, the flowability of the molten wax into the gap is reduced.

On the other hand, when the upward surface of the annular member is the front-facing surface as in the sixth aspect of the invention, the above-described problem does not occur. Positioning can also be achieved by bringing the inner peripheral edge into contact with the tip (tip-facing surface) of the large-diameter cylindrical portion of the tube. In addition, in that case, the lower end of the gap is also blocked, so that it is possible to prevent adhesion due to the wraparound of the wax toward the rear end facing surface. In addition, as for the said notch part, like the invention of Claim 4, it is preferable to form so that it may continue in the circumferential direction along the inner periphery of an annular member. On the other hand, when the notch has the same cross section along the circumferential direction, in order to solve the above problem, for example, in the form of a separate cut from the outside toward the outer peripheral surface of the tube at the bottom of the notch. It is preferable to provide a groove (flow path for flowing wax). The notch may be chamfered or concave, and the cross-sectional shape thereof, that is, the cross-sectional shape forming the depressed concave groove formed with the outer peripheral surface of the tube, should be appropriate. That's fine. In particular, the width (dimension in the radial direction) may be set in consideration of a range that does not interfere with (is not in contact with) the seating surface behind the screw hole of the attachment target site.

The longitudinal cross-sectional view which shows an example of embodiment of the sensor which actualized 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. The elements on larger scale explaining the sensor which used the modification for the annular member. It is explanatory drawing which shows another example of an annular member, 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. 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. An annular member , which is a reference invention different from the present invention, is used, and an explanatory view of a process of brazing the annular member with the tip of the tube facing upward. The figure is a longitudinal sectional view after brazing. 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 fitting a hollow bolt member on the tube and screwing it into a screw hole at the attachment target site, and presses this against the seating surface behind the screw hole. The longitudinal cross-sectional view explaining the sensor attached by attaching. Explanatory drawing of the process of carrying out the external fitting of the annular member to a tube, and brazing in the manufacture process of the sensor of FIG.

  Embodiments of the present invention will be described in detail with reference to the drawings. First, a configuration of an exemplary embodiment of a sensor embodying the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, reference numeral 101 denotes a sensor, which is disposed inside a metal (for example, SUS) tube 11 with a distal end (lower end in FIG. 1) 12 closed, and the distal end 12 of the tube 11 or a portion closer to the distal end. Sensor element 21 and the like. 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, although the detail of the tube 11 is mentioned later, the tube 11 of this example is made into the thing of the concentric different diameter formed by expanding in multiple steps from the front-end | tip 12 toward back. Moreover, in this example, the tube 11 has the second straight pipe portion 15 positioned closer to the tip than the middle thereof, and is inserted into the tube insertion hole 32 inside the annular member 31 with a gap fit, and the inner peripheral surface 32a The outer peripheral surface 15a of the second straight pipe portion 15 of the tube 11 is 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 in the sensor 101 of this example forms a short cylindrical ring, and the rear end-facing surface 35 of the flat annular surface that forms an upward surface in FIG. A notch 37 having an inclined chamfered shape is formed at an angle formed with the peripheral surface 32a along the inner periphery in the form of being continuous in the circumferential direction in this example. The cross section is the same along the circumferential direction. 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 to 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 the element support 22 a lead wire composed of 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, in the manufacturing process of such a sensor, the tube 11 is inserted into the annular member 31 which is a part before brazing (see FIG. 2), and brazing is performed. An example (first embodiment) embodying the brazing process, which is the main part of the method, will be described. 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 from the distal end 12 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, in this example, the tip 12 of the tube 11 is in contact with the support base surface 201. That is, the support jig 211 is arranged so that the front-facing surface 16 of the large-diameter cylindrical portion 17 of the tube 11 is separated from the notch portion 37 located on the inner peripheral edge of the rear-end facing surface 31 of the annular member 31 by an appropriate amount. The height is set.

  Next, a predetermined amount of solder is placed in or near the notch 37 in the rearward facing surface 35 that forms the upward surface of the annular member 31 that is externally fitted to the tube 11 that is set up in this manner. A material 220 is arranged. 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 in or near the notch 37 on the rear end facing surface 35 of the annular member 31.

  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 in the vicinity of the notch 37 in the rear end facing surface 35 or in the vicinity of the notch 37. At the same time, the molten wax flows so as to be drawn 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 31 by capillary action, and spreads wet. Thus, after cooling and solidification, the outer peripheral surface is brazed with the copper solder 230 (see the right figure in FIG. 3).

  By the way, in this brazing process, in this example, the notch portion 37 forms a concave groove that is recessed along the circumferential direction at a portion near the outer peripheral surface 15a of the tube 11 in the rear end facing surface 35 that forms the upward surface. ing. For this reason, the solder melted in this brazing process does not spread out on the rear-facing surface 35 but enters the concave groove formed by the notch 37, and the outer peripheral surface 15 a of the small-diameter cylindrical portion 15 and the annular member 31 It flows into the gap with the peripheral surface 32a. Since the concave groove forms a wax reservoir, after brazing, a part of the wax accumulates in the notch 37 and solidifies. Thus, in this example, since there is a concave groove formed by the notch portion 37, compared to the case without this, the molten solder is less likely to spread and spread on the rear end facing surface 35 that forms the upward surface. The effect of suppressing or preventing the adhesion of wax to 35 can be obtained.

  Thus, a sensor (finished product) is obtained by incorporating each part into the tube 11 after the brazing process (the tube 11 with the annular member 31) as described above. As shown in FIG. 4, the obtained sensor is obtained by fitting a hollow bolt member 301, which is a separate part, to the tube 11 constituting the sensor 101 from behind, and attaching the hollow bolt member 301 to a portion to be attached ( In FIG. 4, the attachment is performed by screwing into a screw hole 510 in a two-dot chain line 500 with a predetermined torque. That is, the hollow bolt member 301 that is externally fitted to the tube 11 with the tip-facing surface 33 of the annular member 31 forming the sensor 101 applied to the seat surface 520 that forms a tapered taper at the back of the screw hole 510, It faces the screw hole 510 and is 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, and the front-end facing surface 33 is pressed against the seat surface 520 at the back of the screw hole 510. . At this time, in the sensor 101 of this example, the attachment of the solder to the rear end facing surface 35 of the annular member 31 pushed by the hollow bolt member 301 is suppressed or prevented. Since there is no insufficient pressing force or uneven pressing force, stable sealing performance is maintained.

  As shown in FIG. 4, the hollow bolt member 301 described above has an inner diameter of the hollow portion (circular hole) 310 concentric with the screw 333 of the outer peripheral surface 330 from the outer diameter of the large-diameter cylindrical portion 17 of the tube 11. In addition, the inner peripheral surface of the hollow portion 310 is set to be located outside the outer peripheral end of the notch portion 37. Accordingly, the solder accumulated in the notch 37 is configured not to interfere with the tip (surface) 305 of the hollow bolt member 301. Further, in this example, the corner 315 formed by the tip (surface) 305 of the hollow bolt member 301 and the inner peripheral surface of the hollow portion 310 is provided with a rounded chamfer along the circumferential direction. It is set so that interference with the accumulated wax is further prevented. At the rear end (the upper end in the figure) of the hollow bolt member 301, a polygonal portion (tool engaging portion) 334 for turning screw having a diameter larger than that of the screw 333 is provided in FIG.

  In the above-described example, the annular member 31 has a chamfered cut along the inner periphery only at the angle formed by the inner peripheral surface 32a and the rear end facing surface 35 before brazing. Although the notch 37 is formed, as shown in FIG. 5, a notch 39 is also formed along the inner periphery at an angle formed by the inner peripheral surface 32a and the tip-facing surface 33. You may keep it. In this way, even when there are a lot of brazing and overflowing from the lower end of the gap, the notch 39 located at the lower end forms a concave groove forming a brazing pool. It is possible to suppress or prevent adhesion of the wax to the tip-facing surface 33 due to wet spreading. In FIG. 5, the notch 39 has a circular cross section and a concave shape. However, as shown by a dotted line (broken line) in FIG. It is good also as what is made, and it is good also as the chamfered notch part 37 in the rear end facing surface 35. FIG. Conversely, the notch in the rear end-facing surface 35 may have a circular arc-shaped cross section as shown by a dotted line (broken line) in FIG. It is good also as the notch part 37 which makes a concave shape by shape. That is, the notch part in this invention should just be a chamfering shape (inclined chamfering, a round chamfering), or a concave shape.

  Further, in the annular member 31 used in the sensor 101 of FIG. 1, the notched portion 37 provided on the rear end facing surface 35 side has an inclined chamfered shape with a constant cross section along the circumferential direction. However, the notch in the present invention may not have a constant cross section along the circumferential direction. FIG. 6 shows an example. Like the annular member 231 shown in the figure, a groove 38 that is inclined downward from the outer periphery toward the center of the tube (axis G) is formed at the bottom of the notch 37 so as to be cut at an appropriate number of locations. It is good also as a thing of a different cross section along the circumferential direction. In this way, as shown in FIG. 7, the distal end 12 of the tube 11 becomes a free end (separated from the base surface 201), and the distal-facing surface of the large-diameter cylindrical portion 17 of the tube 11. Even if 16 is supported by being in contact with the notch 37 of the rear end facing surface 31 of the annular member 31, the flow of the molten wax is secured by the groove 38.

  That is, in such a case, if the groove 38 is not provided, the tip 16 of the large-diameter cylindrical portion 17 closes the upper end of the gap, so the flow of the molten wax in or near the notch 37 is poor. Become. On the other hand, when the groove 38 is provided, it can flow 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 31 using the groove 38 as a flow path. . Although there are three grooves 38 in FIG. 6, more grooves 38 may be formed. This is because the groove 38 also forms a wax pool. The notch 37 is preferably formed so that the outer diameter thereof is as large as possible within a range that does not hinder the screwing of the hollow bolt member and an appropriate amount of brazing pool is obtained.

Next, a reference example (reference embodiment) that embodies a brazing process that forms the main part of the manufacturing method of the reference invention different from the present invention will be described with reference to FIG. However, this reference example differs from the above example in that the above example was brazed with the tip 12 of the tube 11 facing down, but conversely the brazed with the tip 12 facing up. 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. The annular member 331 has a notch that has a cross-sectional, bowl-shaped (L-shaped) concave shape along the inner periphery at an angle formed by the inner peripheral surface 32a and the tip-facing surface 33 before brazing. What formed the part 39 is used.

  As shown in FIG. 8, the tube 11 is vertically set up by a guide jig 221 installed on the support base surface 201 so that the tip 12 thereof is positioned upward (see the left diagram in FIG. 8). Next, the annular member 331 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, as for the annular member 331, the front end surface 33 becomes an upward surface, and the rear end surface 35 becomes a downward surface. A portion closer to the inner peripheral edge of the rear end facing surface 35 is supported by the distal end 16 of the large-diameter cylindrical portion 17 of the tube 11. If necessary, the annular member 331 may be supported by a separate support jig 231 to prevent the tube 11 from being inclined.

Next, a predetermined amount of brazing material 220 is placed in or near the notch 39 in the tip-facing surface 33 that forms the upward surface of the annular member 331 that is externally fitted to the tube 11 erected in this way. Or apply. Then, the brazing material 220 is melted by heating to a brazing temperature for a predetermined time. As a result, 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 331 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. 8). Also in this case, the notch 39 forms a concave groove that is recessed along the circumferential direction at a portion near the outer peripheral surface 15a of the tube 11 in the tip-facing surface 33 that forms an upward surface. Since the groove forms a wax pool in which the melted wax accumulates in the brazing process, it is possible to suppress or prevent the molten solder from spreading on the tip-facing surface 33 that forms the upward surface as in the above example. That is, in this reference example , the tip-facing surface 33 is brazed so that the tip-facing surface 33 forms an upward surface. In this case, the effect of suppressing or preventing the adhesion of the wax to the tip-facing surface 33 is obtained. .

Even in the case where the tube 11 is brazed so that the tip 21 is positioned upward as in this reference example , the inner periphery 32a and the rear end-facing surface 35 are formed at the angle formed by the inner periphery 32a. In addition, by forming the notch portion 37 along the line, even if there is an excessive wax that overflows at the lower end of the gap, it is possible to suppress or prevent the wax from adhering to the rear end facing surface 35.

  In the above example, the tube 11 is a 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, and a method of manufacturing the sensor using such a tube 11. Although embodied, the tube which comprises the sensor of this invention is not limited to this. For example, even when a tube 11 having the same diameter is used later as shown in FIG. 9, it can be applied in the step of brazing the annular member 31 to the tube 11. FIG. 9 illustrates the case where brazing is performed with the tip 12 of the tube 11 facing down, but the present invention can be similarly applied to any of the preceding and following. In FIG. 9, the notch portion 37 is in a state where the tube 11 with the annular member 31 externally fitted is erected, and the cutout portion 37 is formed only on the rear end facing surface 35 that forms the upward surface of the annular member 31 in that state. However, it may also be formed on the tip-facing surface 33.

  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 37 of annular member Notch 101 Sensor 220 Brazing material 301 Hollow bolt member 500 Sensor installation target site 510 Screw hole 520 Seat surface behind screw hole

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 attached, so that the rear end-facing surface of the annular member faces forward with the hollow bolt member. In the sensor configured to press and hold the seal by attaching the tip-facing surface of the annular member to the seating surface at the back of the screw hole,
Before the brazing, the annular member has at least an angle formed by the inner peripheral surface and the rear end facing surface among the angles formed by the inner peripheral surface, the front end facing surface, and the rear end facing surface. While a chamfered or concave notch is formed along the inner circumference ,
The hollow bolt member has an end on the inner peripheral surface of the hollow portion formed outside the outer peripheral end of the notch portion formed at an angle formed by the inner peripheral surface of the annular member and the surface facing the rear end. It is set to be positioned, and at the angle formed by the tip of the hollow bolt member and the inner peripheral surface of the hollow portion, a rounded chamfer is attached along the circumferential direction,
A sensor characterized in that after brazing, a part of the wax accumulates in the notch and solidifies.   The sensor according to claim 1, wherein the notch is formed at both an angle formed by an inner peripheral surface of the annular member and a front end facing surface and a rear end facing surface.   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. 3. The positioning 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 to be positioned in a contact state or a proximity state at a distal end of the radial cylindrical portion. The sensor according to any one of claims.   The sensor according to any one of claims 1 to 3, wherein the notch is formed so as to be continuous in the circumferential direction along the inner periphery of the annular member. 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 set in a standing state, and in the state, a solder is placed in or near the notch in the front-facing surface or the rear-facing surface forming the upward surface of the annular member. The method for manufacturing a sensor according to any one of claims 1 to 4, further comprising a step of placing or applying a material, and then brazing the material by melting the brazing material. 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 a brazing material is disposed or applied in or near the notch portion in the tip-facing surface that forms the upward surface of the annular member in that state. The method for manufacturing a sensor according to claim 3, further comprising a step of brazing by melting the brazing material.

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