JP2009300237A - Temperature sensor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce production cost and improve reliability by simplifying steps of manufacturing temperature sensors for use in EGR systems or exhaust gas purifying systems. <P>SOLUTION: The temperature sensor S supports a one end-closed metal protection tube 2 in a housing 5 having an attachment portion 51 and houses a thermistor element chip 11 within the closed-side end 21 of the protection tube 2. A wire portion W, electrically connected with the element chip 11, has a pair of lead wires 3 of dual-wire configuration of a Du wire 31 of core wire portion and a SUS twisted wire 32, supports insulatively its one end within the protection tube 2, and extends another end as a lead wire 4 with an insulating coat part 41 formed on the periphery. The dual Du wire 31 is exposed at one end of the lead wire 3 within the closed-side end 21 of the protection tube 2 and constructed to connect with the thermistor element chip 11, thereby reducing the number of parts and the number of connecting steps. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a temperature sensor that detects the temperature of a fluid to be measured by projecting a temperature sensing element accommodated in a metal protective tube into a flow path through which the fluid to be measured such as automobile exhaust gas flows.

An exhaust gas recirculation system (hereinafter referred to as an EGR system) that suppresses the generation of NOx and an exhaust gas treatment system that uses a catalyst or the like are widely used in order to comply with automobile engine exhaust gas regulations. In these systems, a temperature sensor is provided in the EGR gas or exhaust gas flow path, and optimal control based on the EGR gas or exhaust gas temperature is performed to reduce exhaust emission. For such applications, a temperature sensor having a high response and a wide detection temperature range is required, and a temperature sensor using a temperature sensitive element such as a thermistor is used (for example, Patent Documents 1 and 2).
Japanese Patent No. 3296034 JP 2004-212269 A

  FIG. 5A shows an example of a conventional temperature sensor configuration. The thermo unit 100 accommodated in the metal protection tube 110, the mounting housing portion 120 for holding the protection tube 110, and the signal The wire part 130 for taking out, the thermo unit 100, and the terminal part 140 for connecting the wire part 130 are provided. The thermo unit 100 includes a thermistor element chip 101 located in the distal end portion of the protection tube 110, a dumet wire (Du wire) 102, and a stainless steel wire (SUS wire) 104, which are lead wires, and an insulator tube 105 for insulating and holding, Du line 102 and SUS line 104 are connected in insulator tube 105. The lead wire 102 protruding from the thermistor element chip 101 and the insulator tube 105 is sealed with glass 103.

  The housing part 120 is fixed to a gas flow path wall (not shown), and the distal end side of the protection tube 103 protrudes into the gas flow path to detect the gas temperature. As shown in FIG. 5B, the wire portion 130 has a configuration in which an outer periphery of a core wire portion 131 (for example, SUS wire) is surrounded by a stranded wire portion 132 (for example, SUS wire) and the whole is covered with an insulating coating portion 133. It has become.

  FIG. 6 shows a manufacturing process of the temperature sensor of FIG. 5. First, a Du wire 102 constituting a part of the lead wire is welded to the thermistor element chip 101 with a gold paste, and a tip portion including the element chip 101 is shown. And glass 103 is welded (steps (1) to (4)). Next, the Du wire 102 is welded with the SUS wire 104 constituting the other part of the lead wire, and is inserted into the insulator tube 105 to form the thermo unit 100 (steps (5) to (6)). Further, the SUS wire 104 drawn from the rear end portion of the insulator tube 105 is welded and fixed to one end side of the terminal portion 140 (step (6)).

  One end of the wire portion 130 is exposed from the insulating coating portion 133 and fixed by welding to the other end side of the terminal portion 140, and the bush 106 is attached to the outer periphery of the wire portion 130 in the vicinity of the terminal portion 140 (step (8)). . Next, the protection tube 110 filled with cement 107 at the tip is covered, and the protection tube 110 is caulked and fixed on the outer periphery of the bush 106 (step (9)).

  In recent years, exhaust gas regulations from automobile engines tend to be strengthened, and a significant reduction in the amount of NOx generated is required. In addition, with increasing accuracy of the EGR system, there is a growing demand for high reliability and low cost for temperature sensors.

  However, in the conventional temperature sensor, the thermo unit 100 and the wire part 130 are connected via the terminal part 140 (B part in FIG. 5), and the joining process from the thermistor element chip 101 to the wire part 130 becomes complicated. was there. Specifically, in FIG. 6, the thermistor element chip 101 and the Du wire 102 are welded (a in the drawing), the glass weld at the tip (b in the drawing), and the Du wire 102 and the SUS wire 104 are welded (c in the drawing). There are five joints: welding of the SUS wire 104 and the terminal part 140 (d in the figure) and welding of the terminal part 140 and the wire part 130 (e in the figure). Needed. In the long term, there is a concern about strength reduction due to repeated application of vibration under conditions heated by high-temperature exhaust gas or the like. For this reason, the production cost increase due to the large number of joining steps and the reliability guarantee for each joining point are problems.

  Accordingly, the object of the present invention is to simplify the manufacturing process of the temperature sensor used in the EGR system and the exhaust gas purification system, to reduce the production cost, and to improve the reliability, thereby reducing the cost of the high-performance temperature sensor. It is to provide.

According to the first aspect of the present invention, a metal protective tube closed at one end is held in a housing having a mounting portion, and the temperature sensing element is accommodated in the closed end portion of the protection tube, and electrically connected to the temperature sensing element. A temperature sensor comprising a wire part to be connected,
The wire portion has a pair of lead wires having a double wire structure in which the outer periphery of the core wire portion is surrounded by another wire, and one end side thereof is insulated and held in the protective tube, while the other end side is covered with an insulating coating. As a lead wire forming a part, it extends to the outside from the open side end of the protective tube,
And the core part of the said double line | wire of the said one end side is exposed within the closed side end part of the said protective tube, It joined to the said temperature sensitive element, It is characterized by the above-mentioned.

  According to the temperature sensor of the present invention, since the wire portion has an integral structure having no joint portion, it is easily manufactured by welding the core portion of the wire portion as a double wire with the temperature sensitive element. This can greatly reduce the number of joints. As a result, the number of parts and the number of manufacturing steps can be reduced, quality variations can be reduced, and reliability can be ensured. Moreover, the wire part can use the optimal wire for the core part joined to the temperature sensing element and the outer peripheral part thereof, respectively, and it is possible to easily achieve both cost and quality.

  Therefore, a high-performance temperature sensor can be manufactured at a low cost, and the temperature detection range is wide as in an exhaust gas purification device for automobiles. Even under conditions where repeated vibrations are applied, there is little risk of disconnection and the like, and excellent durability. So industrial use value is high.

  According to a second aspect of the present invention, the lead wire has a double wire structure composed of the core wire portion and a stranded wire portion surrounding the outer periphery thereof, and the core wire portion is made of a dumet wire.

  Specifically, the present invention can be easily realized by adopting a double wire structure in which the outer periphery of the core wire portion is covered by the stranded wire portion. Using a dumet wire for this core wire part is advantageous for the structure in which the thermosensitive element is sealed in glass within a protective tube, and has the necessary strength and heat resistance, and the thermal expansion coefficient equivalent to that of glass. It can be a cost.

  In the invention of claim 3, the other wire material uses a stainless steel wire as a base material.

  In the lead wire having a double-wire structure, a stranded wire portion surrounding the outer periphery of the core wire portion is preferably made of a stainless steel wire having excellent strength and durability as a base material.

According to a fourth aspect of the present invention, a metal protective tube closed at one end is held in a housing having a mounting portion, a temperature sensing element is accommodated in a closed end portion of the protection tube, and electrically connected to the temperature sensing element. A temperature sensor comprising a wire part to be connected,
The wire portion has a pair of lead wires having a hollow wire structure with at least one end side end portion having no core wire portion, and the one end side is insulated and held in the protective tube, while the other end side is insulated on the outer periphery. As the lead wire formed, it extends from the open side end of the protective tube to the outside,
And in the closed end part of the said protective tube, the lead part provided in the said thermosensitive element was penetrated in the said one end side edge part opening | mouth of the said hollow wire, It was characterized by the above-mentioned.

  According to the temperature sensor of the present invention, since the wire portion has an integral structure without a joint portion, it can be easily manufactured by welding the lead portion of the temperature sensing element to the wire portion having a hollow wire. The joint location can be greatly reduced. As a result, the number of parts and the number of manufacturing steps can be reduced, quality variations can be reduced, and reliability can be ensured. In addition, since the wire part does not have a core wire part, the wire cost can be reduced, and it is possible to easily achieve both cost and quality by using optimum wire materials for the lead part and the wire part of the temperature sensing element. is there.

  Therefore, a high-performance temperature sensor can be manufactured at a low cost, and the temperature detection range is wide as in an exhaust gas purification device for automobiles. Even under conditions where repeated vibrations are applied, there is little risk of disconnection and the like, and excellent durability. So industrial use value is high.

  According to a fifth aspect of the present invention, the lead portion of the temperature sensitive element is made of a dumet wire.

  Specifically, using a jumet wire for the lead part to be joined to the temperature sensitive element is advantageous for the structure in which the temperature sensitive element is sealed in a protective tube with glass, and has the same strength and heat resistance as glass. Since it has a thermal expansion coefficient, it can be made high quality and low cost.

  In the invention of claim 6, the lead wire is formed of a stranded wire having a stainless steel wire as a base material.

  As the lead wire having a hollow wire structure, a stainless steel wire excellent in strength and durability is preferably used.

  According to a seventh aspect of the present invention, the one end side of the pair of lead wires is insulated and held by the insulator tube accommodated in the closed side end portion of the protective tube.

  Preferably, the lead wire accommodated in the protective tube is held and fixed by the insulator tube, whereby insulation between the pair of lead wires and the metal protective tube can be ensured.

Invention of Claim 8 is a manufacturing method of the temperature sensor of any one of Claim 1 thru | or 3, Comprising:
A step of exposing the core portion of the double wire on one end side and forming the pair of lead wires of the wire portion provided with an insulating coating portion on the outer periphery on the other end side;
Bonding the exposed core wire part with the temperature sensing element, and welding the periphery of the joint part and the temperature sensing element;
The temperature sensing element and the one end side of the pair of lead wires are inserted from the opening side end of the protection tube, and the temperature sensing element is disposed in the closing side end of the protection tube. And a step of insulating and holding the pair of lead wires.

  According to the above manufacturing method, the bonding portion of the wire portion is only one portion where the temperature sensing element and the core wire portion are joined, and even if the temperature sensing element is glass-sealed, compared with the conventional method in which the terminal portion is interposed. Thus, the production cost can be greatly reduced by reducing the number of parts and the number of joining processes. In addition, quality variations are reduced by reducing the number of joints, and reliability is improved.

Invention of Claim 9 is a manufacturing method of the temperature sensor of any one of Claims 4 thru | or 6, Comprising:
Bonding the lead portion to the temperature sensitive element, and welding the periphery of the junction and the temperature sensitive element;
Forming the pair of lead wires of the wire portion with a hollow wire structure having no core wire portion at least on one end side; and
Inserting the lead portion of the thermosensitive element into the hollow wire on the one end side, and joining the two;
The temperature sensing element and the one end side of the pair of lead wires are inserted from the opening side end of the protection tube, and the temperature sensing element is disposed in the closing side end of the protection tube. And a step of insulating and holding the pair of lead wires.

  According to the above manufacturing method, the bonding portion of the wire portion is only one portion where the lead portion of the temperature sensitive element and the hollow wire on the one end side are joined. Compared to the conventional method of interposing, the production cost can be greatly reduced by reducing the number of parts and the number of joining processes. In addition, quality variations are reduced by reducing the number of joints, and reliability is improved.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1A shows the overall configuration of a temperature sensor S to which the present invention is applied. The temperature sensor S includes a temperature sensing part 1 having a thermistor element chip 11 as a temperature sensing element, and a protection tube that is a metal protective tube. 2 and the housing 5 for attachment, and the wire part W for signal extraction. The temperature sensor S is suitably used for temperature detection in an exhaust gas treatment system of an automobile engine, for example, an EGR system. The EGR system is a system that suppresses the generation of NOx due to a rise in combustion temperature by recirculating a part of exhaust gas in intake air, and controls the operation of the system based on the detection result of the temperature sensor S.

In FIG. 1A, a temperature sensing unit 1 is obtained by enclosing a thermistor element chip 11 whose electrical resistance varies with temperature in a glass 12. As the thermistor, a generally known NTC thermistor, for example, one having Y (Cr, Mn) O ₃ as a main component can be used. The element chip 11 is obtained by blending ceramic raw material powder constituting the thermistor and firing a molded body having a predetermined shape (for example, a cylindrical shape) at a high temperature. Or after baking the molded object shape | molded in the sheet form, it obtains by cutting to the dimension which can obtain a predetermined resistance value.

  The protection tube 2 is a cylindrical tube with one end closed, and is made of a metal such as SUS (stainless steel). The temperature sensing unit 1 is held and fixed in the closed side end portion 21 (the left end portion of FIG. 1A) of the protection tube 2 using a cement 13 made of alumina or the like. The housing 5 that supports the outer periphery of the intermediate portion of the protection tube 2 has a thick cylindrical shape, and is made of a metal such as SUS (stainless steel) or iron. The housing 5 has a screw-like mounting portion 51 on the outer periphery of the left half of the figure, and is screwed to an engine exhaust pipe wall (not shown) by the mounting portion 51. Thereby, the temperature sensing part 1 protected by the protection tube 2 is made to protrude in the flow path in the exhaust pipe, and the exhaust temperature is measured.

  FIGS. 1B and 1C show the configuration of the wire portion W which is a characteristic part of the present invention. As shown in FIG. 1B, the wire portion W of the present embodiment has an integrated structure without a joint portion, and has an element chip 11 and a pair of lead wires 3 that are directly joined. . The lead wire 3 has one end connected to the element chip 11 inserted and held in an insulator tube 33 made of alumina or the like, and the portion exposed from the insulator tube 33 to the other end is shown in FIG. As shown in FIG. 4, the entire outer periphery is covered with an insulating coating portion 41 to form a lead wire portion 4. The insulator tube 33 is formed with a pair of through holes for inserting the lead wires 3 in the axial direction, and ensures insulation between the pair of lead wires 3 and between each lead wire and the protection tube 2.

  In FIG. 1C, the lead wire 3 is composed of a dumet wire (Du wire) 31 that is a core wire portion and a SUS stranded wire 32 that is a stranded wire portion, and the outer periphery of the dumet wire 31 is another wire material. The SUS wire has a double wire structure surrounded by a SUS stranded wire 32 having a stranded wire structure. The lead wire 3 has an end portion on the element chip 11 side protruding from the insulator tube 33 in a state in which the dumet wire 31 of the core wire portion is exposed, and this jumet wire 31 is directly joined to the element chip 11 to be protected. It arrange | positions in the closed side edge part 21 of.

The dumet wire 31 is formed by forming a metal coating layer such as Cu on the surface of a wire made of Fe—Ni alloy, and further forming a metal oxide layer on the surface. Since the joint portion with the element chip 11 is then sealed with glass, the strength necessary for a lead wire (for example, 100 MPa or more), heat resistance (for example, 900 ° C. or more), and a thermal expansion coefficient equivalent to that of glass (for example, 7 to 7). 9 × 10 ⁻⁶ or more) is required, and a jumet line 31 satisfying these is preferably used. Although other metal wires having equivalent characteristics, such as platinum wires, can be used, the dumet wire 31 is inexpensive and advantageous in terms of cost.

  In the protection tube 2, the lead wire 3 and the element chip 11 held by the insulator tube 33 are placed in the half part (left half part of FIG. 1A) from the intermediate part held in the housing 5 to the closed end side. The half part on the open end side (the right half part in FIG. 1A) in which the lead wire part 4 that accommodates and has the insulating coating part is accommodated has a slightly large diameter. A rubber bush B is mounted around the lead wire portion 4 at the open end portion of the protection tube 2 (the right end portion in FIG. 1A), and the bush B mounting portion is caulked and fixed from the outer periphery. This caulking portion 22 ensures airtightness and waterproofness.

Next, the manufacturing process of the temperature sensor S having the above configuration will be described in detail with reference to FIG.
First, in the step (1) in the figure, the pair of lead wires 3 of the wire portion W are inserted into a pair of through holes provided in the insulator tube 33 from one end side where the jumet wire 31 is exposed. In the subsequent steps (2) and (3), the jumet wire 31 and the element chip 11 are welded using a gold paste, and in the step (4), the entire element chip 11 including the joint portion with the dumet wire 31 is made of glass. 12 and the temperature sensing part 1 and the wire part W are integrated.

  In the step (5) in the figure, the bush B is mounted on the outer periphery of the lead wire portion 4 of the wire portion W close to the insulator tube 33 in the integrated product of the temperature sensing portion 1 and the wire portion W. Next, in step (6), the closed end portion of the protection tube 2 fitted with the housing 5 is filled with cement 13 made of alumina or the like as a base material, and extrapolated from the element chip 11 side, and the temperature sensing portion 1 and the lead wire are inserted. Part of the part 4 is accommodated. Thereafter, the protection tube 2 is caulked and fixed around the outer periphery of the bush B, and hermetically sealed to obtain the temperature sensor S.

  The temperature sensor S of the present embodiment has an integral structure in which the wire portion W does not have a joint portion, and does not have a conventional terminal portion in the portion A of FIG. And the joining location is welding by the gold paste of the element chip 11 of the temperature sensing part 1 and the dumet wire 31 of the wire part W (FIG. 2 (2), (3) process: a), and the glass of the temperature sensing part 1. It becomes only two places of welding (FIG. 2 (3), (4) process: b). For this reason, reliability is increased by reducing the number of welded portions, variation is reduced, and quality is improved. In addition, since the terminal portion is not provided as in the prior art, the number of parts can be reduced and the number of manufacturing steps can be reduced, so that the manufacturing is facilitated.

  Furthermore, since the lead wire 3 of the wire portion W has a double wire structure in which different wire materials are combined, the core wire portion 31 is used as a dumet wire 12 for glass welding, ensuring heat resistance during welding and thermal expansion with glass. Reliability can be increased by reducing the difference in coefficients. Since the dumet wire 12 is cheaper than, for example, a platinum wire or the like, it is used as the core wire portion 31 over the entire length of the wire portion W, and the cost does not increase. Moreover, since the SUS stranded wire 32 is arranged on the outer periphery of the dumet wire 12, the strength of the lead wire 3 can be ensured.

  According to the present embodiment, the temperature sensor S having high performance and excellent durability can be realized, and the manufacturing cost can be reduced. Therefore, for example, in an exhaust gas purification system such as an EGR system, the temperature of the recirculated exhaust gas can be detected with accuracy over a long period of time, and can contribute effectively to the reduction of NOx.

  3 and 4 show a second embodiment of the present invention. FIG. 3A shows the overall configuration of the temperature sensor S in this embodiment. The temperature sensor 1 has the same basic configuration as that of the first embodiment and includes a thermistor element chip 11 that is a temperature sensitive element. The protection tube 2 that is a protective tube, a housing 5 for attachment, and a wire portion W for signal extraction are configured. Hereinafter, the difference from the first embodiment will be mainly described.

  As shown in FIG. 3 (b), in the present embodiment, the temperature sensing unit 1 joins the element chip 11 of the thermistor, which is a temperature resistance element, to a jumet wire 14 (Du line) that becomes a pair of lead parts in advance. The glass 12 has a configuration enclosed in the glass 12. As the thermistor, a generally known NTC thermistor is used, and the element chip 11 is obtained by firing a ceramic raw material powder constituting the thermistor into a molded body having a predetermined shape (for example, a cylindrical shape). Or after baking the molded object shape | molded in the sheet form, it obtains by cutting to the dimension which can obtain a predetermined resistance value.

  3B and 3C, the wire portion W of the present embodiment has an integrated structure without a joint portion, and a pair of lead wires 6 that are directly joined to the jumet wire 14 of the temperature sensing portion 1. have. The lead wire 6 is composed of a SUS stranded wire 61 in which the SUS wire has a hollow stranded wire structure, and a portion corresponding to the core wire portion has a hollow hollow wire structure. The lead wire 6 has one end connected to the temperature sensing unit 1 inserted and held in an insulator tube 33 made of alumina or the like, and the portion exposed from the insulator tube 33 to the other end is shown in FIG. As shown in FIG. 2, the lead wire portion 7 is formed by covering the entirety with an insulating coating portion 71. The insulator tube 33 is formed with a pair of through holes for inserting the lead wires 6 in the axial direction, and ensures insulation between the pair of lead wires 6 and between each lead wire and the protection tube 2.

  In FIG. 3A, the temperature sensing unit 1 inserts the dumet wire 14, which is a lead portion, into the lead wire 6 having a hollow wire structure that opens into the closed end portion 21 of the protection tube 2. Is joined to the SUS stranded wire 61 surrounding the outer periphery. A configuration in which the open-side half of the protection tube 2 has a large diameter, accommodates the lead wire portion 4 to which the rubber bush B is mounted, forms a caulking portion 22 by applying force from the outer periphery of the bush B, and is hermetically sealed. This is the same as in the first embodiment.

Next, the manufacturing process of the temperature sensor S configured as described above will be described in detail with reference to FIG.
First, in steps (1) and (2) in the figure, the element chip 11 is welded and electrically connected to a pair of jumet wires 14 serving as lead portions using a gold paste. In the subsequent steps (3) and (4), the entire element chip 11 including the joint with the dumet wire 14 is sealed with the glass 12 to constitute the temperature sensing part 1 and further joined to the wire part W. At this time, the dumet wire 14 of the temperature sensing portion 1 is inserted into the hollow lead wire 6 from the end portion of the wire portion W that does not have the insulation coating portion 71, and is formed by brazing, resistance welding, laser welding, or the like. The wire 61 and the SUS stranded wire 61 are joined.

  In this way, the temperature sensing part 1 and the wire part W are integrated, and the wire part W is attached to the outer circumference of the lead wire part 7 in the steps (5) and (6), and then the temperature sensing part. An insulator tube 33 is attached to the outer periphery of the lead wire 6 on the part 1 side. At this time, the insulator tube 33 is composed of two members having the same shape and divided in half in the axial direction, and a pair of axial grooves 34 provided in each member are abutted to hold the lead wire 6 therein. Like to do. Next, in step (7), cement 13 such as alumina is filled in the closed end portion of the protection tube 2 to which the housing 5 is attached, and is extrapolated from the element chip 11 side, and one of the temperature sensing portion 1 and the lead wire portion 7 is inserted. House part. Thereafter, the protection tube 2 is caulked and fixed around the outer periphery of the bush B, and hermetically sealed to obtain the temperature sensor S.

  Also in this embodiment, since the wire part W of the temperature sensor S has an integrated structure without a joint, the same effect can be obtained. That is, the bonding location is the welding of the element chip 11 of the temperature sensing portion 1 and the jumet wire 14 which is the lead portion by the gold paste (FIG. 4 (1), (2) step: a) and the temperature sensing portion 1. There are only three locations: glass welding (steps (3) and (4) in FIG. 4: b) and joining of the dumet wire 14 and the lead wire 6 (step (c) in FIG. 4 (5)). For this reason, reliability is increased by reducing the number of welded portions, variation is reduced, and quality is improved. Moreover, since the number of manufacturing steps is reduced, manufacturing is facilitated and the number of parts can be reduced.

  Furthermore, since the lead wire 6 of the wire portion W has a hollow wire structure that does not have a core wire portion, a wire corresponding to the core wire portion is unnecessary, and the temperature sensitive portion 1 can be easily joined to the lead portion. The lead wire 6 is composed of a SUS stranded wire 32 and can ensure strength. Moreover, since the material of the lead part of the temperature sensitive part 1 can be selected arbitrarily, the heat resistance can be ensured and the reliability can be improved by adopting the glass welded jumet wire 31. The dumet wire 12 is cheaper than, for example, a platinum wire, and can be reduced in cost because it is used only for the temperature sensing unit 1.

  Therefore, according to the present embodiment, the temperature sensor S having high quality and excellent durability can be realized, and the manufacturing cost thereof can be reduced. For example, the temperature sensor S can be suitably used for an exhaust gas purification system such as an EGR system.

  As described above, according to the present invention, since the wire portion is integrally formed, the temperature sensitive element and the wire portion can be connected without using the terminal portion, and the number of joints can be greatly reduced. A high-quality temperature sensor can be manufactured at low cost by reducing the number of bonding steps, improving the reliability, and reducing the cost by eliminating the need for the terminal portion.

  In addition, this invention is not limited to the structure of the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention. For example, the element configuration and shape of the temperature sensing element, the shape of the protection tube that houses the temperature sensing element, the insulation holding structure in the protection tube, the configuration and materials of other members, and the like can be changed as appropriate.

  The temperature sensor of the present invention has been described as being used for an EGR system or an exhaust gas treatment system. However, the temperature sensor is not limited to an automobile exhaust gas or various systems for automobiles, but is a temperature sensor that detects the temperature of various fluids to be measured. Of course, it can be used.

(A) is an axial sectional view showing the entire configuration of the temperature sensor according to the first embodiment of the present invention, and (b) illustrates the configuration of the temperature sensing part and the wire part, which are the main parts of the temperature sensor. It is an axial sectional view for the purpose, and (c) is a radial sectional view of the wire portion. It is a figure which shows the manufacturing process of the temperature sensor in the 1st Embodiment of this invention. (A) is an axial direction sectional view showing the whole temperature sensor composition concerning a 2nd embodiment of the present invention, and (b) explains the temperature sensing part and wire part composition which are the principal parts of a temperature sensor. It is an axial sectional view for the purpose, and (c) is a radial sectional view of the wire portion. It is a figure which shows the manufacturing process of the temperature sensor in the 2nd Embodiment of this invention. (A) is an axial direction sectional view which shows the whole structure of the conventional temperature sensor, (b) is radial direction sectional drawing of the wire part of a temperature sensor. It is a figure which shows the manufacturing process of the conventional temperature sensor.

Explanation of symbols

B Rubber bush S Temperature sensor W Lead wire part 1 Temperature sensing part 11 Thermistor element chip (temperature sensing element)
12 Glass 13 Cement 14 Lead part 2 Protection tube (protection tube)
21 Closed end 21
3 Pair of lead wires 31 Dumet wire (core wire)
32 SUS stranded wire (stranded wire)
33 Insulator tube 4 Lead wire part 41 Insulation coating part 5 Housing part 51 Mounting part 6 A pair of lead wires 61 SUS stranded wire 7 Lead wire part 71 Insulation coating part

Claims (9)

Hold the metal protective tube closed at one end in the housing with the mounting part,
While accommodating the temperature sensing element in the closed side end of the protective tube,
A temperature sensor comprising a wire portion electrically connected to the temperature sensitive element,
The wire portion has a pair of lead wires having a double wire structure in which the outer periphery of the core wire portion is surrounded by another wire, and one end side thereof is insulated and held in the protective tube, while the other end side is covered with an insulating coating. As a lead wire forming a part, it extends to the outside from the open side end of the protective tube,
A temperature sensor characterized in that the core wire portion of the double line on the one end side is exposed in the closed end portion of the protective tube and joined to the temperature sensitive element.   2. The temperature sensor according to claim 1, wherein the lead wire has a double wire structure including a core wire portion and a stranded wire portion surrounding the outer periphery thereof, and the core wire portion includes a dumet wire.   The temperature sensor according to claim 1 or 2, wherein the other wire of the lead wire is made of a wire made of a stainless wire as a base material. Hold the metal protective tube closed at one end in the housing with the mounting part,
While accommodating the temperature sensing element in the closed side end of the protective tube,
A temperature sensor comprising a wire portion electrically connected to the temperature sensitive element,
The wire portion has a pair of lead wires having a hollow wire structure with at least one end side end portion having no core wire portion, and the one end side is insulated and held in the protective tube, while the other end side is insulated on the outer periphery. As the lead wire formed, it extends from the open side end of the protective tube to the outside,
And the temperature sensor characterized by inserting the lead part provided in the said temperature sensing element in the said one end side edge part opening | mouth of the said hollow wire in the closed side edge part of the said protective tube, and joining with the said hollow wire.   The temperature sensor according to claim 4, wherein the lead portion of the temperature sensitive element is made of a dumet wire.   6. The temperature sensor according to claim 4, wherein the lead wire is a stranded wire having a stainless wire as a base material.   The temperature sensor according to any one of claims 1 to 6, wherein the one end side of the pair of lead wires is insulated and held by an insulator tube accommodated in a closed side end portion of the protective tube. A temperature sensor manufacturing method according to any one of claims 1 to 3,
A step of exposing the core portion of the double wire on one end side and forming the pair of lead wires of the wire portion provided with an insulating coating portion on the outer periphery on the other end side;
Welding the exposed core wire portion with the temperature sensitive element, and welding the welded portion and the periphery of the temperature sensitive element with glass;
The one end side of the temperature sensing element and the pair of lead wires is inserted from the opening end of the protection tube, the temperature sensing element is arranged in the closing side end of the protection tube, and the temperature sensing element is placed in the protection tube. And a step of insulating and holding between the pair of lead wires. A temperature sensor manufacturing method according to any one of claims 4 to 6,
Welding the lead part to the temperature sensitive element, and welding the welded part and the periphery of the temperature sensitive element;
Forming the pair of lead wires of the wire portion provided with a hollow wire portion having a hollow center portion at least on one end side; and
Inserting the lead portion of the temperature sensing element into the hollow wire portion on the one end side, and joining the two;
The one end side of the temperature sensing element and the pair of lead wires is inserted from the opening end of the protection tube, and the temperature sensing element is disposed in the closing side end of the protection tube, and the temperature sensing element is disposed in the protection tube. And a step of insulating and holding between the pair of lead wires.

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