JP5123058B2 - Manufacturing method of temperature sensor - Google Patents

Description

The present invention relates to a method of manufacturing a temperature sensor having a temperature sensing element having a temperature sensing portion, such as a thermistor or Pt resistor.

Conventionally, as temperature sensors that can be used over a wide temperature range, for example, techniques described in Patent Documents 1 to 4 below are disclosed.
In the temperature sensors described in these patent documents, a terminal wire constituting a thermistor element for detecting temperature and an electrode wire such as a sheath core wire to which a lead wire for connecting an external circuit is overlapped to perform laser welding or It is integrated by welding such as resistance welding, and the integrated member is placed in a housing closed at one end, and the housing is filled with insulating cement to ensure heat resistance and vibration resistance. Yes.
JP 2005-55254 A JP 2004-301679 A JP 2000-266609 A Japanese Patent Laid-Open No. 2000-234962

  By the way, in the temperature sensor, a Pt or PR (Pt / Rh alloy) wire having a high heat resistance and a low electrical resistance is used for the terminal wire of the thermistor element, and the heat resistance, strength and cost are used for the sheath core wire. In view of the above, stainless steel or inconel is used, but there are the following problems.

  In other words, because the thermal expansion coefficient (thermal expansion coefficient) of the thermistor element terminal wire and sheath core wire are different, the higher the temperature, the more the thermistor element tends to bend from the welded part. Since it is fixed with cement, it cannot be displaced, and a large stress is generated in the welded portion. When the temperature sensor is used in an environment where the temperature changes drastically as in an internal combustion engine and is exposed to a high temperature, a large stress is repeatedly applied to the welded portion. As a result, there was a risk of breakage or peeling of the welded part.

The present invention has been made in view of such a problem. For example, in a method of manufacturing a temperature sensor used in an environment where the temperature changes drastically as in an internal combustion engine and is exposed to a high temperature, for example , An object of the present invention is to improve the reliability of a welded portion between a terminal wire such as a thermistor element and an electrode wire such as a sheath core wire.

( 1 ) The invention of claim 1 includes a temperature sensing element having a temperature sensing part whose electrical characteristics change with temperature, and a terminal wire extending from the temperature sensing part, and is connected to the terminal line, and the temperature sensing element A temperature sensor manufacturing method comprising: an electrode wire for taking out an electrical signal from a tube; and a cylindrical housing that is closed at a distal end side and houses the temperature sensing element and the electrode wire, wherein the terminal wire or the electrode wire After fitting an annular or U-shaped intermediate member having a thermal expansion coefficient between the thermal expansion coefficient of the terminal wire and the thermal expansion coefficient of the terminal wire into the terminal wire and the electrode wire in the axial direction A first step of integrally joining the terminal wire, the intermediate member, and the electrode wire by welding a portion where the terminal wire and the electrode wire are overlapped with each other. It is characterized by that.

  In the present invention, the terminal wire and the electrode wire are not directly welded, but the terminal wire or the electrode wire is annular or U-shaped, and the heat between the thermal expansion coefficient of the terminal wire and the thermal expansion coefficient of the electrode wire. An intermediate member having an expansion coefficient is fitted and welded to be integrated.

  As a result, the thermal expansion coefficient is inclined from the terminal wire to the electrode wire at the welded portion (welded portion), so even when the temperature sensor is used in an environment where the temperature change is severe, the welded portion between the terminal wire and the electrode wire. Stress can be relaxed, and reliability can be greatly improved.

As the thermal expansion coefficient of the intermediate member, depending on the thermal expansion coefficient of the terminal wire and the electrode wire, and a range of, for example, ^{8.8 × 10 -6 /℃~14.4×10 -6 / ℃} .
Further, as the thickness d _B of the intermediate member, when the radius of the terminal lines r _1, the radius r ₂ of the electrode _{line, (r 1 + r 2)} / 8 ≧ d B ≧ (r 1 + r 2) / 40 The range of is preferable. This is because if the thickness of the intermediate member is within this range, the effect of stress relaxation can be sufficiently obtained after welding, and as shown in FIGS. This is because the terminal wire, the intermediate member, and the electrode wire can be welded at a time during welding such as welding, which facilitates the work.

Note that the thickness d _A (see FIG. 5) of the intermediate layer after completion of welding is equal to or smaller than the thickness d _{B of the} intermediate member (d _A ≦ d _B ). This is because the terminal wire, the intermediate member, and the electrode wire are fixed with a pressing jig and welded with a laser, and at the moment of melting, the force applied by the pressing jig acts in the direction of crushing the intermediate member. degree of d _A is smaller than d _B is the magnitude of the force applied by the pressing tool, it depends laser power, such as the composition of the intermediate member.
Furthermore, various methods such as laser welding and resistance welding can be employed as the welding method.

( 2 ) In the invention of claim 2 , after the first step, the temperature-sensitive element and the electrode wire integrated by welding by filling the cylindrical housing with unsolidified insulating cement, It has a 2nd process installed in the front end side of the housing, and a 3rd process which solidifies the insulating cement by heating and fixes the temperature sensing element and the electrode wire.

The present invention exemplifies a suitable manufacturing process after the first process.
( 3 ) The invention of claim 3 is characterized in that the intermediate member is an alloy mainly composed of Pt and Ni.

  The present invention exemplifies a preferred composition of the intermediate member. The total content of Pt and Ni is greater than 50% by mass (preferably 90% by mass or more). Moreover, since Pt and Ni are completely dissolved, the content of Ni is not particularly limited. However, since the melting point decreases as the Ni content increases, from the viewpoint of heat resistance and from the viewpoint of oxidation resistance, Ni Is preferably 10 to 20% by mass in the total amount of Pt and Ni.

( 4 ) The invention of claim 4 is characterized in that the temperature sensor is used in an environment where the temperature change width is 500 ° C. or more.
The present invention illustrates a preferred application of the temperature sensor obtained by the manufacturing method described above.

In the invention of each claim described above, for example, a thermistor, a platinum resistor, or the like can be adopted as the temperature sensing part of the temperature sensing element.
Examples of the electrode wire include a wire made of stainless steel or Inconel, and examples of the range of the thermal expansion coefficient include 10.0 × 10 ^{−6 to} 17.3 × 10 ⁻⁶ / ° C. Moreover, the sheath core wire penetrated by the cylindrical member can be used as the electrode wire, and the cylindrical member can be insulated and held in a state where the distal end of the sheath core wire corresponding to the electrode wire protrudes from the cylindrical member. it can.

Examples of the terminal wire include a wire made of Pt or PR (Pt / Rh alloy). The range of the thermal expansion coefficient is, for example, 8.2 × 10 ^{−6 to} 8.8 × 10 ⁻⁶ / ° C. Is mentioned. In addition, although the ratio of Rh in a Pt / Rh alloy is not specifically limited, 3-13 mass% is suitable considering material characteristics, such as cost, intensity | strength, and hardness.

Next, a preferred embodiment of the present invention will be described.
[Outline of temperature sensor]
First, the outline | summary of the temperature sensor of this embodiment is demonstrated. FIG. 1 is a partially broken cross-sectional view showing the structure of the temperature sensor 1.

  The temperature sensor 1 includes a sheath member 7 in which a pair of metal sheath core wires (electrode wires) 3 are insulated and held inside the tubular member 5, and a tubular metal tube (housing) extending in the axial direction with the distal end closed. 9, a mounting member 11 that supports the metal tube 9, a nut member 17 having a hexagonal nut portion 13 and a screw portion 15, and an outer cylinder 19 that fits inside the rear end side of the mounting member 11.

  The axial direction is the longitudinal direction of the temperature sensor 1 and corresponds to the vertical direction in FIG. Moreover, the front end side in the temperature sensor 1 is a lower side in the figure, and the rear end side in the temperature sensor 1 is an upper side in the figure.

  This temperature sensor 1 is a sensor in which a thermistor element 21 is housed as a temperature-sensitive element inside the tip side of the metal tube 9 and is mounted on a flow pipe such as an exhaust pipe of an internal combustion engine, for example. The temperature of the measurement target gas is detected by being arranged in the flow pipe through which the target gas (exhaust gas) flows.

  The thermistor element 21 includes a thermistor sintered body (temperature-sensitive portion) 23 whose electrical characteristics (electrical resistance value) change according to temperature, and a pair of thermistor elements 21 for extracting changes in electrical characteristics of the thermistor sintered body 23. And a terminal line 25.

Hereinafter, each configuration will be described in detail.
The sheath core wire 3 has a distal end connected to the terminal wire 25 of the thermistor element 21 by, for example, laser welding, and a rear end connected to the crimping terminal 27, for example, by resistance welding. Thus, the sheath core wire 3 is connected at its rear end side to a lead wire 29 for connecting an external circuit (for example, an electronic control unit (ECU) of a vehicle) via the crimping terminal 27.

  The pair of sheath core wires 3 and the pair of crimping terminals 27 are insulated from each other by an insulating tube 31, and the lead wire 29 has a conductive wire covered with an insulating covering material and the inside of an auxiliary ring 33 made of heat-resistant rubber. Arranged in a penetrating state.

  The sheath member 7 is configured to electrically insulate between the cylindrical member 5 made of metal, a pair of sheath core wires 3 made of a conductive metal, and the cylindrical member 5 and the two sheath core wires 3. 3 and insulating powder 34 such as silica (see FIG. 2).

  The mounting member 11 includes a projecting portion 35 projecting radially outward, and a rear end side sheath portion 37 that is located on the rear end side of the projecting portion 35 and extends in the axial direction. The attachment member 11 surrounds the outer peripheral surface on the rear end side of the metal tube 9 and supports the metal tube 9.

  The metal tube 9 is made of a corrosion-resistant metal (for example, a stainless alloy such as SUS310S which is also a heat-resistant metal), and has a cylindrical shape extending in the axial direction in which the tube tip side is closed by deep drawing of a steel plate. The rear end side of the tube is open.

  2 and 3, the metal tube 9 has a small-diameter portion 41 on the distal end side whose diameter is set small, and a large-diameter on the rear end side whose diameter is set larger than the small-diameter portion 41. And a step 45 between the small-diameter portion 41 and the large-diameter portion 43.

  Further, the thermistor element 21 and the cement 39 are accommodated in the metal tube 9, and the cement 39 is filled around the thermistor element 21, thereby preventing the thermistor element 21 from swinging. The cement 39 is made of an insulating material containing alumina aggregate in amorphous silica.

  In particular, in this embodiment, the rear end side (right side in FIG. 2) of the terminal wire 25 of the thermistor element 21 and the front end side (left side in FIG. 2) of the sheath core wire 3 are welded 47 (FIG. 3) by laser welding. )).

  That is, as further enlarged in FIG. 4, between the terminal wire 25 and the sheath core wire 3 arranged in parallel with each other, the half of the shape (semi-annular) in which the cylinder is half broken along the axis is provided. A member 49 is disposed, and the welded portion 47 (the same figure) is welded and integrated with the terminal wire 25, the intermediate member 49, and the sheath core wire 25 by laser welding at two locations on the left and right sides with the intermediate member 49 as the center. (Hatched portion) is formed.

Specifically, as shown in the AA cross section of FIG. 4 in FIG. 5, in the welded portion 47, the terminal wire 25 is connected to the fractured surface fractured perpendicular to the axial direction of the terminal wire 25 and the sheath core wire 3. Between the first projection region X projected in the axial direction and the second projection region Y similarly projected in the axial direction of the sheath core wire 3 on the fracture surface, the thermal expansion coefficient of the terminal wire 25 and the sheath core wire 3 An intermediate layer 51 having a thermal expansion coefficient between the thermal expansion coefficients is formed.
Note that the first projection region X corresponds to a region (corresponding to a region formed by the outline of the terminal line 25 and the dotted line L1) in which the terminal line 25 is projected in the axial direction on the fracture surface, and the second projection region Y is This corresponds to a region (corresponding to a region formed by the outline of the electrode line 3 and the dotted line L2) in which the electrode line 3 is projected in the axial direction on the fracture surface.

In FIG. 5, the intermediate layer 51 does not belong to the first projection region X and the second projection region Y when the center Ox of the first projection region X and the center Oy of the second projection region Y are connected by a straight line. Shown as an intermediate region having a width d _A.

  In this intermediate layer 51, the components of the terminal portion 25 and the sheath core wire 3 are mixed in addition to the components of the intermediate member 49 due to melting by laser welding, but the components of the intermediate member 49 serving as the base are the most contained. Therefore, the thermal expansion coefficient thereof has an intermediate thermal expansion coefficient between the thermal expansion coefficient of the terminal wire 25 and the thermal expansion coefficient of the sheath core wire 3.

The method for obtaining the thermal expansion coefficient of the intermediate member 49 after welding is the same as described above, and is omitted here.
[Method of manufacturing temperature sensor]
Next, a method for manufacturing the temperature sensor 1 will be described.

In order to manufacture the temperature sensor 1 of the present embodiment, parts such as the metal tube 9, the sheath member 7, the attachment member 11, and the thermistor element 21 that are formed in advance are prepared by a known method.
Then, as shown in FIG. 4, the pair of terminal wires 25 of the thermistor element 21 are overlapped and welded to the distal ends of the pair of sheath core wires 3 of the sheath member 7 in the axial direction.

Specifically, as the terminal wire 25, for example, a PR wire having a diameter of 0.3 mm and a thermal expansion coefficient of 8.7 × 10 ⁻⁶ / ° C. (Pt 90 mass% —Rh 10 mass% alloy wire: hereinafter, mass% is omitted. ) Is used. As the intermediate member 49, for example, the thickness is 0.03 mm, the length (the length in the direction curved along the inner diameter) is 0.45 mm, the width (the length along the axial direction of the terminal wire 25) is 1.5 mm, A rectangular alloy plate of Pt—Ni alloy (Pt90—Ni10) having a thermal expansion coefficient of 10.8 × 10 ⁻⁶ / ° C. is used and is bent in a semi-annular shape so that the diameter (inner diameter) is 0.3 mm. As the sheath core wire 25, for example, a stainless steel wire (SUS310S) having a diameter of 0.5 mm and a thermal expansion coefficient of 14.4 × 10 ⁻⁶ / ° C. is used. That is, as the intermediate member 49, a material having a thermal expansion coefficient intermediate between the thermal expansion coefficient of the terminal wire 25 and the thermal expansion coefficient of the sheath core wire 3 is used.

  Then, as shown in FIG. 6, a semi-annular intermediate member 49 is fitted to the terminal wire 25, the terminal wire 25 and the sheath core wire 3 are arranged in parallel with each other with the intermediate member 49 interposed therebetween, and a pressing force (not shown) The terminal wire 25, the intermediate member 29, and the sheath core wire 3 are pressed and fixed from above and below by the jig.

  Next, for example, from the right side of FIG. 6, the laser beam is irradiated so that the laser beam hits a range of about 0.4 mm in diameter over the lower side of the terminal wire 25, the intermediate member 49, and the upper side of the sheath core wire 3. Laser welding is performed, and the terminal wire 25, the intermediate member 49, and the sheath core wire 3 are welded together.

As the laser welding conditions, for example, an Nd: YAG laser can be used, and the laser power can be 1.0 J and the irradiation time can be 2.0 ms.
In the present embodiment, the intermediate layer 51 formed by welding the terminal wire 25 and the sheath core wire 3 using the intermediate member 49 is also positioned between the thermal expansion coefficients of the terminal wire 25 and the sheath core wire 3. To do.

  Thereafter, as shown in FIG. 1, the metal tube 9 is inserted into the attachment member 11, and the metal tube 9 is attached to the stepped portion 53 by performing caulking work and welding work inward in the radial direction. The member 11 is integrated.

Subsequently, a tip part 53 (see FIG. 7) composed of the sheath member 7 to which the thermistor element 3 is welded and the metal tube 9 to which the attachment member 11 is welded is assembled.
This operation will be described with reference to FIG. FIG. 7 is a flowchart showing a method for manufacturing the tip part 53.

  In manufacturing the tip component 53, first, the nozzle 55 is inserted into the tip portion of the metal tube 9 to which the mounting member 11 is welded in a state in which the thermistor element 21 is not inserted, and is pasty, that is, uncured. The cement 39 in the state is injected.

  Then, the sheath member 7 to which the thermistor element 21 is welded is inserted into the metal tube 9 into which the cement 39 is injected. At this time, the distal end portion of the tubular member 5 of the sheath member 7 is brought into contact with the inner periphery of the stepped portion 45 of the metal tube 9 to place the thermistor element 21 in the cement 39.

  Then, with the sheath member 7 inserted into the inside of the metal tube 9, long hole crimping is performed in which the metal plate 9 is pressed against the metal tube 9 from the outside in the radial direction while facing the plate-shaped mold 57. By this long hole caulking, the metal tube 9 and the sheath member 7 are completely positioned and fixed.

In this way, the tip part 53 is completed. Then, a known centrifugal defoaming process (for example, see Japanese Patent Application Laid-Open No. 2007-170952) is performed on the tip part 53.
When the centrifugal defoaming process is completed, the tip part 53 is heat-treated at 800 ° C., and the cement 39 is dried (cured).

In this way, the tip part 53 after the heat treatment is obtained.
Next, the tip part 53 and other parts are assembled. That is, as shown in FIG. 1, the outer cylinder 19 has the crimping terminal 27, the insulating tube 31, and the auxiliary ring 33 accommodated therein, and the portion corresponding to the auxiliary ring 33 is crimped, thereby assisting The auxiliary ring 33 is crimped and joined while maintaining airtightness with the ring 33. In addition, the front end side of the outer cylinder 19 is welded in a state of being externally fitted to the rear end side sheath portion 37 of the attachment member 11.

  The mounting member 11 is arranged so that the mounting seat 59 is in contact with the tapered surface of the sensor mounting position in a state where the nut member 17 is rotatably fitted around the outer cylinder 19, and then the nut member The 17 screw portions 15 are screwed into thread grooves formed around the sensor mounting position, so that the sensor mounting position is fixed. That is, the attachment member 11 is fixed in a state of being sandwiched between the nut member 17 and the tapered surface of the sensor attachment position.

  The external circuit connected to the temperature sensor 1 via the lead wire 29 takes out the electrical characteristics of the thermistor element 21 (thermistor sintered body 23) that changes according to the temperature of the object to be measured, and takes out the electrical The temperature of the exhaust gas can be detected based on the characteristics.

[Effect of this embodiment]
As described above, in the present embodiment, the intermediate member 49 having a thermal expansion coefficient between the terminal wire 25 and the sheath core wire 3 is arranged between the terminal wire 25 and the sheath core wire 3. Since the laser welding is performed with the intermediate member 49 as the center, the thermal expansion coefficient of the terminal wire 25 and the sheath core wire 3 are between the terminal wire 25 and the sheath core wire 3 in the welded portion 47 which is the welded portion. An intermediate layer 51 having a thermal expansion coefficient between the thermal expansion coefficients is formed.

  That is, in the temperature sensor 1 of the present embodiment, the terminal wire 25 and the sheath core wire 3 have an intermediate thermal expansion coefficient between the terminal wire 25 and the sheath core wire 3, and have heat resistance (high melting point). Since it is joined by the intermediate layer 51 formed from the intermediate member 49 having excellent thermal conductivity and high electrical conductivity, it is used in harsh environments where the temperature changes suddenly with a large width of 500 ° C. or more. Even in such a case, the stress applied to the welded portion 47 at a high temperature or the like can be relaxed. Therefore, it is possible to prevent the welded portion 47 from being broken or broken, so that the welded portion 47 and thus the temperature sensor 1 is excellent in reliability.

[Experiment for confirming the effect of the present invention]
Next, experimental examples conducted for confirming the effects of the present invention will be described.
The temperature sensor of Example 1 was manufactured by the manufacturing method shown in the embodiment.

  Specifically, as shown in FIG. 6, a Pt90-Ni10 alloy plate having a thickness of 0.03 mm is processed into a semi-annular shape and an intermediate member (for example, a U-shaped member formed by cutting a cylinder in half in the axial direction). 49, and this intermediate member 49 is fitted to a terminal wire 25 made of a PR alloy (Pt90-Rh10 alloy) having a thermistor element diameter of 0.3 mm, a sheath core wire 3 made of SUS310S having a diameter of 0.5 mm, and laser welding. Thus, the temperature sensor of Example 1 was manufactured.

  Then, the thermistor element joined to the sheath core wire 3 is placed in a metal tube filled with cement made of alumina and silica, and kept in a furnace at 900 ° C. for 5 hours to cure the cement. A sensor was manufactured.

Further, the temperature sensor of Example 2 was manufactured as shown in FIG.
Specifically, an intermediate member obtained by processing a Pt85-Ni15 alloy plate having a thickness of 0.04 mm into a 1/4 ring shape on a sheath core wire 61 made of SUS310S having a diameter of 0.5 mm (a cylinder is ¼ along the axial direction). A U-shaped member 63 having a shape divided into two is manufactured, and the intermediate member 63 is placed on the sheath core wire 61 and laser welded to a terminal wire 65 made of a PR alloy having a thermistor element diameter of 0.3 mm. Thereafter, the temperature sensor of Example 2 was manufactured in the same manner as Example 1.

Then, using the temperature sensors of Examples 1 and 2, the following experiment was performed.
a) Temperature cycle heat resistance test As shown in FIG. 9, the temperature sensors 71 and 73 of Examples 1 and 2 were fixed to the moving device 75 and moved in the left-right direction in FIG. A temperature cycle heat test for taking in and out of the furnace 79 was performed.

In detail, the operation of holding at room temperature for 5 minutes outside the furnace 79 and holding at 950 ° C. for 5 minutes in the furnace 79 was repeated 300 cycles.
After the durability test, the temperature was measured using the temperature sensors 71 and 73. As a result, the temperature could be detected normally, and there was no problem with the durability of the temperature sensors 71 and 73.

b) Burner Heating Vibration Test As shown in FIG. 10, the temperature sensors 71 and 73 of Examples 1 and 2 were fixed to the vibration tester 81 and heated at a frequency of 100 Hz at a frequency of 100 Hz while being heated by a burner. sec ² ) of acceleration vibration was applied for 20 hours in each direction (20 hours in the X direction and 20 hours in the Y direction).

After the durability test, the temperature was measured using the temperature sensors 71 and 73. As a result, the temperature could be detected normally, and there was no problem with the durability of the temperature sensors 71 and 73.
[Other Embodiments]
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.

(1) For example, as shown in FIG. 11, an annular intermediate member 93 may be externally fitted to the terminal wire 91, and the terminal wire 91 and the sheath core wire 95 may be laser-welded via the intermediate member 93.
Moreover, although the material which can be selected as a terminal wire, an intermediate member, and an electrode wire is shown in following Table 1, according to the usage location etc. of a temperature sensor, a material can be suitably selected within the scope of the present invention.

In addition, the number added to Pt, Rh, Ni, etc. has shown the mass%.

(2) The present invention can also be applied to the temperature sensor 101 having the configuration shown in FIG.
That is, the temperature sensor 101 shown in FIG. 12 includes a metal cap 103 instead of the metal tube 9 of the above embodiment. The metal cap 103 has a cylindrical shape extending in the axial direction with the front end side (downward in the figure) closed, and has a configuration in which the cylindrical rear end side is opened.

  Further, the metal cap 103 accommodates the thermistor element 105 and the cement 107 (filler) inside the front end side, and the inner peripheral surface on the rear end side overlaps the outer peripheral surface of the tubular member 111 of the sheath member 109. Thus, it is fixed to the sheath member 109 by being welded all around.

  Further, the attachment member 115 in the temperature sensor 101 has a shape that can be directly assembled with the sheath member 109, although details are omitted. Such a mounting member 115 has a radial direction with respect to each of the second step portion 121 formed with a smaller diameter than the joint portion 117 and the first step portion 119 after the sheath member 109 is inserted into the attachment member 115. By performing inward caulking work and welding work, the sheath member 109 is supported by surrounding the outer peripheral surface of the tubular member 111 of the sheath member 109. That is, the sheath member 109 is fixed to the attachment member 115 by being bonded to the bonding portion 117 and the second step portion 121.

  Also in such a temperature sensor 101, the terminal wire 127 extending from the thermistor sintered body 126 of the thermistor element 105 and the sheath core wire (electrode wire) 129 constituting the sheath member 109 are an intermediate member (see FIG. Therefore, the same effect as that of the temperature sensor 1 of the above embodiment can be obtained.

It is a fragmentary sectional view which shows the structure of the temperature sensor of embodiment. It is a front view which fractures | ruptures and expands and shows the front end side of a temperature sensor. It is a side view which fractures | ruptures and expands and shows the front end side of a temperature sensor. It is explanatory drawing which expands and shows the welding part of a terminal wire and a sheath core wire. It is AA sectional drawing of FIG. It is explanatory drawing which shows the method of laser welding. It is explanatory drawing explaining the manufacturing process of a temperature sensor. 6 is an explanatory view showing a laser welding method in Embodiment 2. FIG. It is explanatory drawing which shows the method of a temperature cycle heat test. A burner heating vibration test is shown, (a) is an explanatory view showing a side surface of the test apparatus in a broken state, and (b) is an explanatory view showing the test apparatus from the front. It is explanatory drawing which shows the other method of laser welding. It is a fragmentary sectional view which shows the structure of the temperature sensor of a modification.

Explanation of symbols

1, 71, 73, 101 ... Temperature sensor 3, 61, 95, 127 ... Sheath core wire (electrode wire)
9 ... Metal tube (housing)
7, 109: Sheath member 21, 105: Thermistor element 23, 126: Ceramic sintered body (temperature sensing part)
25, 65, 93, 127 ... terminal wire 39, 107 ... cement 47 ... welded portion 49, 63, 91 ... intermediate member 51 ... intermediate layer

Claims (4)

A temperature sensing element having a temperature sensing portion whose electrical characteristics change with temperature, and a terminal wire extending from the temperature sensing portion;
An electrode wire connected to the terminal wire and taking out an electrical signal from the temperature sensitive element;
A cylindrical housing in which the tip side is closed and houses the temperature sensing element and the electrode wire;
A method of manufacturing a temperature sensor comprising:
After fitting an annular or U-shaped intermediate member having a thermal expansion coefficient between the thermal expansion coefficient of the terminal wire and the thermal expansion coefficient to the terminal wire or the electrode wire, the terminal wire and The terminal wires, the intermediate member, and the electrode wires are integrated with each other by welding the portions where the electrode wires and the electrode wires are overlapped with each other by welding the electrode wires. A temperature sensor manufacturing method comprising a first step of bonding. After the first step,
A second step of filling the cylindrical housing with unsolidified insulating cement and installing the temperature-sensitive element and the electrode wire integrated by the welding on the front end side of the housing;
A third step of solidifying the insulating cement by heating and fixing the temperature sensitive element and the electrode wire;
The method of manufacturing a temperature sensor according to claim 1 , wherein: The intermediate member, manufacturing method of the temperature sensor according to claim 1 or 2, characterized in that an alloy mainly composed of Pt and Ni. The temperature sensor, the width of the temperature change, method for producing a temperature sensor according to any one of claims 1 to 3, characterized in that used in the 500 ° C. or higher environment.