JP2006126067A - Method for manufacturing temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a temperature sensor, which enables an appropriate bonding operation to be carried out while preventing any filling matter from attaching to regions near an aperture section in the inner face of a metal cap, the regions where a sheath member is bonded. <P>SOLUTION: The temperature sensor 1 employs an insulating member 6 made of a solid resin as a filling matter with which the inside of the metal cap 3 is filled up, whereby the insulating member 6 is prevented from attaching to the regions near the aperture section (regions near the rear-end section) in the inner face of the metal cap 3, when disposing the insulating member 6 inside the metal cap 3. That is to say, while a filling matter in a softened state or paste state is easy to attach to the inner face of the metal cap 3, the insulating member 6 made of solid resin in a solid state is difficult to attach to the inner face of the metal cap 3. The insulating member 6 used as the filling matter is thereby prevented from attaching to the portion (fastening section 39 shown in detail) which is the region near the aperture section in the inner face of the metal cap 3 and where the sheath member 8 is bonded, and fastening accuracy and weldability are prevented from lowering caused by influences of the insulating member 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a temperature sensor that detects the temperature of an object to be detected (gas, liquid, etc.).

  Conventionally, as a temperature sensor for detecting the temperature of an object to be detected (gas, liquid, etc.), a temperature sensor having a metal cap that houses the temperature sensing element (sensor element) in order to protect the temperature sensing element (sensor element). It has been known.

  In a temperature sensor including such a metal cap, when the inner surface of the metal cap and the sensor element are provided through a gap without contact, there is a problem that heat is difficult to conduct and responsiveness is reduced. On the other hand, there is a temperature sensor having a configuration in which a filler is provided inside a metal cap in order to improve thermal conductivity to the sensor element and improve responsiveness to temperature changes (Patent Documents 1 and 2). reference).

  That is, since the filler forms a heat conduction path between the sensor element and the metal cap, the heat conduction between the sensor element and the metal cap becomes good, and the sensor responsiveness to a temperature change can be improved. In addition, as a filler, resin, an inorganic adhesive agent, etc. can be used, for example.

Moreover, since the sensor element is supported on the inner surface of the metal cap via the filler by providing the filler, not only the thermal conductivity can be improved, but also the earthquake resistance can be improved.
As a method of manufacturing such a temperature sensor, for example, first, a softened or pasty filling is injected into a metal cap, and then a sensor element (specifically, a sensor element and a sheath member (MI cable) There is a manufacturing method of a procedure in which the sensor element portion of the assembly in which the metal cap is integrally connected is inserted and arranged inside the metal cap, and the metal cap and the sheath member are joined by welding or the like.
Japanese Patent Laid-Open No. 11-218449 (FIG. 3) JP 2002-267546 A (FIG. 2)

  However, in the above-described conventional temperature sensor manufacturing method, when the filler is injected into the metal cap, the filler is in a softened state or a paste state. It tends to adhere and the filler may adversely affect the bonding.

  That is, since the filler is a material having a melting point lower than that of the metal constituting the metal cap or sheath member (MI cable), the filler is vaporized during the welding operation, and bubbles are present in the welded portion. There is a problem that the welding strength between the metal cap and the sheath member is lowered. In addition, in the case of caulking and joining, if there is a foreign substance such as a filler, the joining strength between the metal cap and the sheath member may be reduced, and the airtightness in the metal cap may be reduced.

  Accordingly, the present invention has been made in view of such problems, and a temperature sensor that can perform an appropriate joining operation without a filler adhering to the vicinity of an opening serving as a joining portion with a sheath member on an inner surface of a metal cap. It aims at providing the manufacturing method of.

  The invention according to claim 1, which has been made to achieve such an object, includes a bottomed cylindrical metal cap that extends in the axial direction with the tip side closed, a temperature sensing element whose electrical characteristics change according to temperature, A sheath member having a metal core wire to which a temperature sensing element is connected at the front end side and a lead wire for connecting an external circuit to the rear end side, and the metal core wire is insulated and held in a protective tube. The front end portion of the protective tube of the sheath member to which the temperature element and the temperature sensitive element are connected is housed inside the metal cap, and the rear end side portion of the metal cap and the front end portion of the protective tube are fixed. The temperature sensor and the temperature sensitive element are connected in a state where the solid resin softened by heating is placed inside the metal cap, and the solid resin is softened by heating. Tip of the sheath member A second step of inserting the metal cap into the inside of the metal cap, and a third step of joining the overlapping portion of the metal cap and the protective tube of the sheath member and fixing the metal cap and the protective tube. It is a manufacturing method of a temperature sensor.

  According to this method of manufacturing a temperature sensor, since a solid resin, which is a solid material, is used as a filler to be filled in the metal cap, the metal cap is disposed when the filler (solid resin) is disposed inside the metal cap. It is possible to prevent the filler (solid resin) from adhering to the vicinity of the opening in the interior of the. That is, the filler in the softened state or the paste state has a characteristic that it easily adheres to the inside of the metal cap, whereas the solid resin that is a solid has a characteristic that it is difficult to adhere to the inside of the metal cap.

  As a result, solid resin as a filler can be prevented from adhering to the inside of the vicinity of the opening of the metal cap and fixed to the sheath member, and deterioration of the bondability due to the influence of the solid resin (filler) can be prevented. .

  Therefore, according to the method of the present invention, when joining the metal cap and the sheath member, it is possible to perform an appropriate joining operation, and it is possible to realize a good joining property between the metal cap and the sheath member in the temperature sensor.

  Next, in the above-described temperature sensor manufacturing method, as described in claim 2, the metal cap has, as an internal space portion, a sheath member accommodating portion having an inner diameter dimension equal to or larger than an outer diameter dimension of the protective tube of the sheath member. And an element accommodating portion that is formed on the distal end side of the sheath member accommodating portion and has an inner diameter dimension that is smaller than the inner diameter dimension of the sheath member accommodating portion and larger than the outer diameter dimension of the temperature sensitive element. In the first step, the solid resin may be disposed in the element housing portion of the metal cap, and in the second step, at least a part of the temperature sensitive element may be inserted into the element housing portion.

  As described above, the solid resin adheres to the joint portion by using the metal cap including the sheath member accommodating portion and the element accommodating portion as the internal space portion and including the sheath member accommodating portion having a larger inner diameter than the element accommodating portion. Can be prevented.

  That is, in such a metal cap, since the inner diameter dimension of the sheath portion accommodating portion is larger than that of the element accommodating portion and the inner volume of the sheath portion accommodating portion is large, the element is associated with the insertion of the temperature sensitive element in the second step. Even when the solid resin overflows from the housing portion, it is difficult for the solid resin to reach the vicinity of the opening of the metal cap, and the solid resin can be prevented from adhering to the joint portion.

  In addition, by placing the solid resin in the element housing part of the inside of the metal cap, at least a part of the temperature sensitive element is inserted into the element housing part, so that the solid resin reliably contacts the temperature sensitive element and the inner surface of the metal cap. Can be made. Thereby, solid resin used as the heat conduction path from a metal cap to a temperature sensing element can be formed reliably, and the responsiveness of a temperature sensor can be improved.

  Therefore, according to the method of the present invention, it is possible to prevent the solid resin from adhering to the joining portion. Therefore, when joining the metal cap and the sheath member, it is possible to perform more appropriate joining work, and the metal cap and sheath in the temperature sensor. Good bondability with the member can be realized. In addition, according to the method of the present invention, a solid resin serving as a heat conduction path from the metal cap to the temperature sensitive element can be reliably formed, and the responsiveness of the temperature sensor can be improved.

  In the temperature sensor manufacturing method described above, as described in claim 3, for example, a glass-sealed thermistor formed by sealing the thermistor element with glass can be used as the temperature-sensitive element.

By sealing the thermistor element with glass, it is possible to prevent the surface of the thermistor element from being reduced and change in characteristics of the element over a long period of time.
Therefore, according to the method of the present invention, a highly reliable temperature sensor can be manufactured.

The preferred embodiments of the present invention will be described below.
In addition, this invention is not limited to the following embodiment at all, and it cannot be overemphasized that various forms may be taken as long as it belongs to the technical scope of this invention.

FIG. 1 is a partially broken sectional view showing the structure of a temperature sensor 1 according to this embodiment. FIG. 2 is an enlarged view of the vicinity of the thermistor element 2 in the temperature sensor 1 shown in FIG.
This temperature sensor 1 uses a thermistor element 2 as a temperature sensitive element (sensor element), and is attached to a high-pressure hydrogen cylinder so that the thermistor element 2 is filled with a high-pressure hydrogen gas. It is used for detecting the temperature of hydrogen gas. Such a hydrogen cylinder is attached to a fuel cell system for automobiles, for example.

  The metal cap 3 is formed in a bottomed cylindrical shape whose front end side (lower side in FIG. 1) is closed, and the thermistor element 2 is housed inside the metal cap 3. The metal cap 3 has a bottomed cylindrical shape whose front end is closed while the rear end is open. The metal cap 3 is formed of SUS316. As shown in FIG. 2, the metal cap 3 is formed with a tip portion 31, a tapered portion 32, and a storage portion 33 in order from the tip end side in the axial direction.

  The tip 31 of the metal cap 3 has an axial cross section (a cross section in a plane parallel to the axial direction) having an arc shape, more specifically, the axial cross section has a semicircular shape, and the outer shape has a hemispherical shape. The average thickness is smaller than that of the taper portion 32 and the storage portion 33. In the present embodiment, the average thickness of the tip 31 is 0.2 [mm].

  The tapered portion 32 is located on the rear end side with respect to the distal end portion 31, and is formed in a substantially cylindrical shape. More specifically, the tapered portion 32 is formed such that the outer diameter increases toward the rear end side and the thickness increases toward the rear end side. Here, the outer diameter of the tip of the taper portion 32 matches the outer diameter of the rear end of the tip portion 31, and the outer diameter of the rear end of the taper portion 32 matches the outer diameter of the tip of the storage portion 33. The outer diameter of the taper portion 32 is formed so as to gradually increase from the tip portion 31 to the storage portion 33. In the present embodiment, the outer diameter of the tip of the tapered portion 32 is 2.1 [mm], and the outer diameter of the rear end of the tapered portion 32 is 3.0 [mm]. The average thickness of the tapered portion 32 is 0.6 [mm].

  The tapered portion 32 has an inner hole 51, and the inner diameter of the inner hole 51 is the same as the inner diameter of the rear end of the distal end portion 31, that is, the maximum inner diameter of the distal end portion 31. In the present embodiment, the inner diameter of the inner hole of the tapered portion 32 is 1.7 [mm].

  The storage part 33 is located on the rear end side of the taper part 32 and is a part for storing a part of the sheath member 8 described later. The storage part 33 is formed in a substantially cylindrical shape, and the outer diameter thereof is larger than the outer diameter of the tip part 31.

  The storage portion 33 is formed with a front end side inner hole 52 and a rear end side inner hole 54, and the inner diameter of the front end side inner hole 52 is the same as the inner diameter of the inner hole 51 of the taper portion 32. Here, the inner diameter of the distal end side inner hole 52 is smaller than the outer diameter of the sheath pipe 9 in the sheath member 8 described later. Further, the inner diameter of the rear end side inner hole 54 is larger than the inner diameter of the front end side inner hole 52. Further, a stepped portion 53 is formed between the front end side inner hole 52 and the rear end side inner hole 54, and the inner diameters of the front end side inner hole 52 and the rear end side inner hole 54 are formed at the stepped portion 53. Changes discontinuously. Here, in this embodiment, the average thickness of the storage part 33 is 0.3 [mm].

  The tapered portion 32 and the storage portion 33 are collectively referred to as a rear end portion 34. Further, the average thickness of the taper portion 32 and the storage portion 33 which are the rear end portions 34 are both larger than the average thickness of the front end portion 31.

  The thermistor element 2 includes a thermistor sintered body 21 made of an oxide ceramic which is a temperature sensing portion, and a thermistor sintered body 21 protruding from the thermistor sintered body 21 to the rear end side and corresponding to a temperature change of the gas to be detected. And a pair of Pt / Rh alloy electrode wires 22 for taking out an output signal corresponding to the electrical characteristics. The surface of the thermistor sintered body 21 is covered with glass. Further, a portion of the pair of electrode wires 22 located on the thermistor sintered body 21 side is attached with an alumina ceramic rod 23 for the purpose of preventing a short circuit with other members.

  A part of the thermistor sintered body 21 of the thermistor element 2 is accommodated in the front end part 31 of the metal cap 3, and the remaining part of the thermistor element 2 is accommodated in the rear end part 34 of the metal cap 3. Here, the distal end portion 31 and the tapered portion 32 of the metal cap 3 are filled with an insulating member 6 made of a solid resin that is softened by heating. Therefore, the insulating member 6 is filled between the thermistor sintered body 21 and the metal cap 3.

  The insulating member 6 is a solid resin mainly composed of a polyamide resin, and in the present embodiment, “Product name: Jetmelt 7375” manufactured by Sumitomo 3M Limited is used. Further, the insulating member 6 is not limited to a resin having a polyamide resin as a main component, and may be a resin having an ethylene vinyl acetate copolymer as a main component, or may be blended with glass fibers or the like. Further, the main component means a material having the largest component ratio among the insulating members.

On the rear end side (open side) of the storage portion 33 of the metal cap 3, the sheath member 8 for taking out an output signal from the electrode wire 22 is inserted from the rear end side of the storage portion 33. 33. The sheath member 8 has an outer diameter of 3.0 [mm] and a thickness of 0.5 [mm] and is made of a SUS316L sheath pipe 9, a pair of SUS316L metal core wires 7, a sheath pipe 9, and each metal core wire 7. (Specifically, SiO ₂₎ insulating powder filled between the formed from a metal core wire 7 is held in the sheath pipe 9 in an insulated state.

  In addition, the part which protrudes from the front end side of the sheath pipe 9 among a pair of metal core wires 7 is a pair of front end side metal core wires 71, and the part which protrudes from the rear end side of the sheath pipe 9 among the pair of metal core wires 7 , A pair of rear end side metal core wires 72.

  Here, the distal end of the sheath pipe 9 is positioned on the stepped portion 53 of the storage portion 33 via an insulating holder 10 described later. Further, the pair of electrode wires 22 and the pair of distal end side metal core wires 71 of the thermistor element 2 are connected to each other by resistance welding or laser welding.

  Further, the metal cap 3 and the sheath member 8 are arranged so that the sheath member 8 (specifically, the distal end portion of the sheath pipe 9 of the sheath member 8) is inserted into the storage portion 33 of the metal cap 3 and then the outside of the storage portion 33. By crimping toward the sheath member 8 (sheath pipe 9), the crimping portion 39 formed in the circumferential direction on the rear end side of the storage portion 33 is fixed by crimping. It is integrated by being welded to the end by electron beam all around.

  Furthermore, an insulating holder made of alumina is provided in the housing portion 33 of the metal cap 3 and between the ceramic rod 23 and the sheath pipe 9 of the thermistor element 2 so as to cover the electrode wire 22 and the tip side metal core wire 71. 10 is interposed.

  As shown in FIG. 1, the rear end side of the sheath member 8 is fixed to the attachment member 4 so as to be inserted into the attachment member 4. The attachment member 4 is formed of SUS316, and a sheath portion 41, a reinforcing portion 42, a screw portion 43, a hexagonal portion 44, and a joint portion 45 are integrally formed in this order from the front end side in the axial direction.

  The sheath member 8 and the attachment member 4 are formed in the sheath portion 41 over the circumferential direction by caulking from the outside of the sheath portion 41 toward the sheath member 8 after the sheath member 8 is inserted into the sheath portion 41. While being fixed by the crimping parts 46 and 47, it is integrated by the electron beam welding to the crimping parts 46 and 47 over the circumferential direction.

  Here, when the protruding amount from the tip of the attachment member 4 is large in the sheath member 8, the sheath member 8 is bent or broken due to resonance of the sheath member due to vibration applied to the temperature sensor 1, so that the sheath member 8 is There is a risk of damage. For this reason, by forming a reinforcing portion 42 having a diameter larger than that of the sheath portion 41 between the sheath portion 41 and the screw portion 43, the sheath member 8 is prevented from being damaged even if vibration is applied to the temperature sensor 1. be able to.

  Moreover, the screw part 43 and the hexagonal part 44 are for attaching the temperature sensor 1 to the sensor attachment part of the hydrogen cylinder. By tightening the screw part 43 to the boss part formed in the sensor attachment part, Sensor 1 is attached to a hydrogen cylinder. A portion having an outer diameter smaller than the outer diameter of the screw portion 43 is formed between the screw portion 43 and the hexagonal portion 44, and an O-ring 5 made of fluorine rubber or silicon rubber is fitted into this portion. It is. The O-ring 5 prevents hydrogen gas that is a gas to be detected from leaking to the outside.

  The inner hole of the rear end side of the screw part 43, the hexagonal part 44, and the joint part 45 has a larger diameter than the inner holes of the sheath part 41 and the reinforcing part 42. The rear end side metal core wire 72 protruding from the rear end side of the sheath pipe 9 within the inner holes of the screw portion 43 and the hexagonal portion 44 is connected to a pair of lead wires 12 for connecting external circuits via the crimping terminals 11. It is connected to the. In addition, the lead wire 12 coat | covers the stainless steel wire arrange | positioned in the center, and the nickel plating annealed copper wire which surrounds this circumference | surroundings with the coating | coated member made from PTFE resin.

  The distal ends of the pair of rear end side metal core wires 72, the pair of crimping terminals 11, and the pair of lead wires 12 are electrically insulated from the attachment member 4 by being covered with an insulating tube 15 made of PTFE. Note that an insulating resin or the like may be filled between the inner holes of the screw portion 43 and the hexagonal portion 44 and the insulating tube 15.

  The lead wire 12 is inserted into the auxiliary ring 13 made of fluoro rubber or silicon rubber provided in the joint portion 45. Moreover, the site | part which protrudes from the rear end of the joint part 45 among the lead wires 12 is covered with the insulating tube 16 which consists of glass braiding. Furthermore, the outer periphery of the joint part 45 and the insulating tube 16 is covered with a shrinkable tube 14 made of silicon rubber.

In addition, after arrange | positioning the auxiliary | assistant ring 13 in the inside of the joint part 45, the joint part 45 is fixed inside the joint part 45 by carrying out the round crimping or polygonal crimping to radial direction inward.
Then, the signal output from the thermistor sintered body 21 corresponding to the temperature change of the hydrogen gas that is the gas to be detected is taken out to an external circuit (not shown) via the electrode wire 22, the metal core wire 7 of the sheath member 8, and the lead wire 12. And used for detecting the temperature of hydrogen gas.

Here, since this temperature sensor 1 is used for detecting the temperature of hydrogen gas, each component member needs to have excellent hydrogen embrittlement. For this reason, in this embodiment, the metal cap 3 and the attachment member 4 are formed of SUS316, and the sheath pipe 9 and the metal core wire 7 are formed of SUS316L. The constituent member may be formed of SUS310S or the like in addition to the above materials. '
Next, a manufacturing method of the temperature sensor 1 will be described.

  First, the steel plate made of SUS316 is deep-drawn, or at least one of cold forging and cutting is applied to the metal body made of SUS316, and the tip portion 31, the taper portion 32, and the storage portion 33 are formed. The possessed metal cap 3 is formed. Further, the attachment member 4 having a sheath portion 41, a reinforcing portion 42, a screw portion 43, a hexagonal portion 44, and a joint portion 45 is provided by performing at least one of cold forging and cutting on a metal body made of SUS316. Form.

  Next, the thermistor element 2 is placed on the distal end side of the sheath member 8 by superimposing the electrode wire 22 of the thermistor element 2 and the metal core wire 71 on the distal end side of the sheath member 8 so as to overlap each other by a predetermined size and resistance welding each other. A connected temperature sensing element assembly is produced.

Next, a step of assembling the metal cap 3 to the temperature-sensitive element assembly and storing the thermistor element 2 inside the bottomed cylindrical metal cap 3 is performed.
First, the insulating holder 10 is attached so as to cover the electrode wire 22 and the tip end side metal core wire 71 exposed to the outside between the thermistor sintered body 21 and the sheath pipe 9.

  Next, prior to the insertion of the temperature-sensitive element assembly into the metal cap 3, the insulating member 6 whose main component is a solid polyamide resin that is softened by heating is disposed in the inner hole of the metal cap 3. At this time, the insulating member 6 disposed inside the metal cap 3 may be single or plural.

  In addition, as a case where the some insulating member 6 is used, the example which uses two or more grain-shaped insulating members can be given, for example. As the grain-shaped insulating member, a member having a size that can be disposed in the inner hole 51 of the tapered portion 32 in the metal cap 3 and having a maximum particle size of 0.1 [μm] or more is used. Is desirable.

  That is, a member having a maximum particle size of less than 0.1 [μm] has a small particle size, and thus may adhere to the inner surface of the metal cap 3, whereas the maximum particle size is 0.00. A member having a size of 1 [μm] or more is less likely to adhere to the inner surface of the metal cap 3 when the member is disposed inside the metal cap 3. As a result, the insulating member 6 can be prevented from adhering to the vicinity of the opening in the inner surface of the metal cap 3 and can be easily disposed inside the tip end side of the metal cap 3.

  In addition, the filling efficiency of a member having a small particle size may decrease due to the influence of static electricity or the like, and pores are likely to be generated inside the insulating member 6 after the heat treatment. The heat conduction in the insulating member 6 due to the influence of the pores. There is a risk that the efficiency may decrease. On the other hand, a member having a maximum particle size of 0.1 [μm] or more can prevent a decrease in filling efficiency, and the insulating member 6 after the heat treatment is less likely to have pores. Reduction in efficiency can be suppressed.

Next, the insulating member 6 is heated so that the softened paste-like insulating member 6 exists in the inner hole of the metal cap 3.
Next, the tip side of the temperature-sensitive element assembly (the side on which the thermistor element 2 is provided) is inserted loosely and coaxially from the opening side of the metal cap 3 containing the paste-like insulating member 6. The housing portion 33 is arranged so as to surround the outer surface of the distal end portion of the sheath pipe 9 of the sheath member 8. At this time, a feeling is given so that an overlapping portion having a predetermined dimension is generated in the distal end portion of the sheath pipe 9 in a loosely fitted state, and at least a part of the thermistor sintered body 21 of the thermistor element 2 is accommodated in the distal end portion 31. The warm cord assembly is placed against the metal cap 3.

  The insulating member 6 inside the metal cap 3 is naturally cooled and solidified during the subsequent process, thereby forming a solid insulating member 6 disposed between the inner surface of the metal cap 3 and the thermistor element 2. .

  Here, in this embodiment, when the temperature-sensitive cord assembly is inserted into the metal cap 3, the tip of the sheath pipe 9 is indirectly connected to the stepped portion 53 of the storage portion 33 of the metal cap 3 via the insulating holder 10. By inserting until contact, positioning of the temperature-sensitive element assembly and the metal cap 3 in the axial direction is performed. That is, in this embodiment, the temperature sensing element assembly is inserted loosely and coaxially into the metal cap 3, and the tip of the temperature sensing element assembly is insulated from the stepped portion 53 of the storage portion 33 of the metal cap 3. Each dimension of the metal cap 3 is adjusted in advance so that an overlapping portion having a predetermined dimension is generated at the time of indirect contact with the holder 10. Thereby, the overlapping dimension in the axial direction of the metal cap 3 with respect to the temperature sensitive element assembly can be uniquely determined. As a result, the thermistor sintered body 21 can be reliably arranged at the target position of the tip 31 of the metal cap 3.

  Next, in the overlapping portion between the rear end portion of the storage portion 33 of the metal cap 3 and the distal end portion of the sheath pipe 9, the metal cap 3 positioned on the outer side is caulked in the circumferential direction toward the sheath member 8 positioned on the inner side, A caulking portion 39 is formed. In the present embodiment, this caulking is performed by Happomaru caulking. The caulking portion 39 formed in this manner corresponds to a welded portion forming portion by all-around electron beam welding described later. By forming the caulking portion 39, the caulking portion 39 is formed between the metal cap 3 and the sheath member 8. The amount of gap can be reduced, and welding with excellent welding strength can be performed.

  The caulking portion 39 is irradiated with an electron beam to perform all-around electron beam welding to form a welded portion straddling the metal cap 3 and the sheath pipe 9, and the metal cap 3 and the sheath member 8 Is integrated.

  Next, the sheath member 8 is inserted into the inner hole of the attachment member 4. At this time, the sheath member 8 and the attachment member 4 are arranged so that the rear end side metal core wire 72 of the sheath member 8 protrudes from the rear end of the attachment member 4. Thereafter, using the crimping terminal 11, the rear end side metal core wire 72 of the sheath member 8 and the lead wire 12 are electrically connected.

  Next, the distal ends of the pair of rear end side metal core wires 72, the pair of crimping terminals 11, and the pair of lead wires 12 are covered with the insulating tube 15. Thereafter, the attachment member 4 is moved so that the insulating tube 15 is positioned in the inner holes of the screw portion 43 and the hexagonal portion 44 of the attachment member 4. Next, after crimping from the outside of the sheath portion 41 toward the sheath member 8, electron beam welding is performed on the crimping portions 46 and 47 in the circumferential direction.

  Thereafter, the auxiliary ring 13 is inserted into the joint portion 45 from the rear end side of the joint portion 45 while the pair of lead wires 12 are inserted through the pair of insertion holes formed in the auxiliary ring 13. Next, round caulking or polygonal caulking is performed from the outside of the joint portion 45 toward the auxiliary ring 13 to fix the joint portion 45 and the auxiliary ring 13 in an airtight manner. Thereafter, the portion of the lead wire 12 protruding from the rear end of the auxiliary ring 13 is covered with the insulating tube 16, and the joint portion 45 and the insulating tube 16 are covered so as to cover the joint between the joint portion 45 and the insulating tube 16. The outer periphery is covered with a shrinkable tube 14.

In this way, the manufacture of the temperature sensor 1 is completed.
In the present embodiment, the thermistor element 2 in the temperature sensor 1 corresponds to the temperature-sensitive element described in the claims, the insulating member 6 corresponds to the solid resin, and the sheath pipe 9 corresponds to the protective tube. Further, the rear end side inner hole 54 of the storage part 33 of the metal cap 3 corresponds to the sheath member storage part, the inner hole of the tip part 31 in the metal cap 3 and the inner hole 51 of the taper part 32 correspond to the element storage part. .

  As described above, in the temperature sensor 1 of the present embodiment, since the insulating member 6 made of a solid resin is used as the filling material filled in the metal cap 3, the insulating member 6 is provided inside the metal cap 3. In disposing, the insulating member 6 can be prevented from adhering to the vicinity of the opening (near the rear end) in the metal cap 3. In other words, the softened or pasty filling has the property of easily adhering to the inside of the metal cap 3, whereas the insulating member 6 made of a solid resin that is solid has the property of being difficult to adhere to the inside of the metal cap 3. Have.

  Thereby, it is possible to prevent the insulating member 6 as a filler from adhering to a portion (in detail, the caulking portion 39) that is fixed to the sheath member 8 in the vicinity of the opening of the metal cap 3. It is possible to prevent a decrease in caulking accuracy and weldability due to the influence of the above.

  Therefore, according to the manufacturing method of the temperature sensor 1 of this embodiment, when welding the metal cap 3 and the sheath member 8, an appropriate joining operation | work is attained, and the metal cap 3 and the sheath member 8 in the temperature sensor 1 are made. Good bondability can be realized.

  Moreover, the temperature sensor 1 of this embodiment is provided with the metal cap 3 provided with two space parts from which an internal-diameter dimension differs as an internal space part. That is, the metal cap 3 includes a rear end side inner hole 54 as a space part having a large inner diameter dimension, an inner hole of the tip part 31 as a space part having a small inner diameter dimension, and an inner hole 51 of the taper part 32. I have.

  In the metal cap 3 having such a configuration, the rear end side inner hole 54 of the storage portion 33 has a larger inner diameter than the inner hole of the tip portion 31 and the inner hole 51 of the taper portion 32. The inner volume of the rear end side inner hole 54 of the storage portion 33 is larger than the inner volume of the inner hole 51 of the hole and the tapered portion 32.

  Therefore, even when the insulating member 6 softened by heating overflows from the inner hole 51 of the distal end portion 31 and the inner hole 51 of the tapered portion 32 as the thermistor element 2 is inserted, the insulating member 6 is made of metal. It is difficult to reach the vicinity of the opening of the cap 3, and it is possible to prevent the insulating member 6 from adhering to the portion of the metal cap 3 that becomes the crimped portion 39.

  Further, while the insulating member 6 is disposed in the inner hole of the tip 31 and the inner hole 51 of the taper 32 in the metal cap 3, at least a part of the thermistor element 2 is placed in the inner hole and the taper 32 of the tip 31. The insulating member 6 can be reliably brought into contact with the thermistor element 2 and the metal cap 3 by being inserted into the inner hole 51. Thereby, the insulating member 6 which becomes a heat conduction path from the metal cap 3 to the thermistor element 2 can be reliably formed, and the responsiveness of the temperature sensor 1 can be improved.

  Therefore, according to the manufacturing method of the temperature sensor in the present embodiment, it is possible to prevent the insulating member 6 from adhering to the caulking portion 39 serving as a joining portion, and thus it is possible to perform a more appropriate joining operation. Good bondability between the cap 3 and the sheath member 8 can be realized.

  In the temperature sensor 1 of this embodiment, the axial cross section of the tip portion 31 of the metal cap 3 has an arc shape, and the thickness of the rear end portion 34 is larger than that of the tip portion. Yes. For this reason, even if a compressive force due to a pressure difference between the inside and the outside of the metal cap 3 acts on the metal cap 3, the tip end portion 31 has an arcuate cross section in the axial direction. It can withstand the compression force even if the thickness is small. By disposing the thermistor sintered body 21 at the tip portion 31 having a small wall thickness, it is possible to provide a temperature sensor that can realize high responsiveness while preventing the temperature sensor from being damaged by the compressive force.

  Further, the taper portion 32 of the metal cap 3 is formed such that the outer diameter increases toward the rear end side and the thickness increases toward the rear end side. For this reason, the size of the tip side part of the metal cap 3 (specifically, the tip side of the tip part 31 and the taper part 32) can be reduced. Therefore, the heat volume of the tip side portion of the metal cap 3 can be reduced, and the responsiveness of the temperature sensor can be further improved.

  An insulating holder made of alumina is provided in the housing portion 33 of the metal cap 3 and between the ceramic rod 23 and the sheath pipe 9 of the thermistor element 2 so as to cover the electrode wire 22 and the tip side metal core wire 71. 10 is interposed. For this reason, a short circuit between the electrode wire 22 or the metal core wire 7 and the metal cap 3 can be prevented. Furthermore, even if the compressive force acts on the metal cap 3, the deformation of the metal cap 3 can be suppressed because the insulating holder 10 is disposed inside the metal cap 3.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It can take a various aspect.
For example, the welding method between the metal cap and the sheath member is not limited to electron beam welding, and the metal cap and the sheath member may be integrated using laser welding. Further, a welding technique different from electron beam welding or laser welding may be used as long as the technique can integrate the metal cap and the sheath member.

  Further, the shape of the internal space of the metal cap is not limited to the above embodiment, and the temperature sensing element and a part of the sheath member are appropriately accommodated according to the shape of the temperature sensing element (sensor element) and the sheath member. Any shape can be used.

  The method of the present invention is not limited to a method for manufacturing a temperature sensor for detecting the temperature of hydrogen gas, but a method for manufacturing a temperature sensor used for temperature detection of other gas species such as CNG as a gas to be detected. Can also be applied. Moreover, the temperature sensor manufactured by the method of the present invention can be attached to a liquefied gas cylinder.

  Furthermore, the method of the present invention is not limited to a high pressure gas to be detected, but as a gas to be detected, a method for manufacturing a temperature sensor for an exhaust pipe attached to an exhaust pipe through which exhaust gas of an internal combustion engine flows, or a liquid such as water or oil is used. The present invention can also be applied to a manufacturing method of a flow path temperature sensor attached to a flowing flow path.

It is a fragmentary sectional view which shows the structure of a temperature sensor. It is an enlarged view of the thermistor element vicinity in a temperature sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Temperature sensor, 2 ... Thermistor element, 3 ... Metal cap, 4 ... Mounting member, 6 ... Insulating member, 7 ... Metal core wire, 8 ... Sheath member, 9 ... Sheath pipe, 21 ... Thermistor sintered body, 23 ... Ceramic Gasket, 31 ... tip part, 32 ... taper part, 33 ... storage part, 34 ... rear end part, 39 ... caulking part, 51 ... inner hole, 52 ... tip side inner hole, 53 ... step part, 54 ... rear end Side inner hole.

Claims (3)

A bottomed cylindrical metal cap extending in the axial direction with the distal end closed;
A temperature sensitive element whose electrical characteristics change according to temperature,
A sheath member comprising a metal core wire to which the temperature sensing element is connected at the front end side and a lead wire for connecting an external circuit to the rear end side, and the metal core wire is insulated and held in a protective tube;
A tip end side portion of the protective tube of the sheath member to which the temperature sensing element and the temperature sensing element are connected are housed inside the metal cap, and a rear end side portion of the metal cap and the A method of manufacturing a temperature sensor having a configuration in which a tip side portion of a protective tube is fixed,
A first step of disposing a solid resin softened by heating inside the metal cap;
A second step of inserting the thermosensitive element and the distal end side of the sheath member connected to the thermosensitive element into the metal cap in a state where the solid resin is softened by heating;
A third step of joining the overlapping portion of the metal cap and the protective tube of the sheath member, and fixing the metal cap and the protective tube;
A method for manufacturing a temperature sensor, comprising: The metal cap is formed as an inner space portion, a sheath member accommodating portion having an inner diameter dimension equal to or larger than an outer diameter dimension of the protective tube of the sheath member, and a distal end side of the sheath member accommodating portion. An element housing portion having an inner diameter dimension that is smaller than the inner diameter dimension of the member housing portion and larger than the outer diameter dimension of the temperature-sensitive element,
In the first step, the solid resin is disposed in the element housing portion of the metal cap,
In the second step, inserting at least a part of the temperature sensitive element into the element accommodating portion;
The method of manufacturing a temperature sensor according to claim 1. The temperature sensitive element is a glass-sealed thermistor formed by sealing the thermistor element with glass,
The manufacturing method of the temperature sensor of Claim 1 or Claim 2 characterized by these.

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