JP2009121968A

JP2009121968A - Temperature sensor

Info

Publication number: JP2009121968A
Application number: JP2007296694A
Authority: JP
Inventors: Takashi Noguchi; 隆史野口; Katsumi Tokoro; 克巳所; Hisato Haraga; 久人原賀
Original assignee: WORLDWING CO Ltd
Current assignee: WORLDWING CO Ltd
Priority date: 2007-11-15
Filing date: 2007-11-15
Publication date: 2009-06-04

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature sensor having excellent durability and temperature measurement responsibility. <P>SOLUTION: The temperature sensor 5 is constituted by attaching a thermocouple 20 in a ceramic, such as alumina and the like, protection tube 11. The ceramic protection tube 11, molded with injection molding, includes: a base 12 which is constant in thickness; a taper part 13 whose thickness gradually becomes thinner toward the tip while being continuous to the base 12; a tip part 14 whose thickness is the thinnest while being continuous to the taper part 13; and a fringe part 15 arranged around the boundary part between the base 12 and the taper part 13. The thermocouple 20 includes W-Re wires 21, 22, a glass bead 22 which covers and incorporates the connection part of the wires 21, 22, and a connector 23. Then, the glass bead 22 is pushed into the tip part 14 of the ceramic protection tube 11 and fixed by a filling member 24 whose main component is silicone resin (SiO<SB>2</SB>). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、温水器などに組み込まれる温度センサに関する。 The present invention relates to a temperature sensor incorporated in a water heater or the like.

従来の温度センサはステンレス製保護管（シース）内に熱電対を構成する金属素線を収納している。しかしながら、ステンレス製保護管は耐食性に劣り、高温に晒されると劣化する。そこで、特許文献１〜３に開示されるセラミックス製保護管を用いた温度センサが提案されている。 A conventional temperature sensor houses a metal wire constituting a thermocouple in a stainless protective tube (sheath). However, stainless steel protective tubes are inferior in corrosion resistance and deteriorate when exposed to high temperatures. Therefore, a temperature sensor using a ceramic protective tube disclosed in Patent Documents 1 to 3 has been proposed.

特許文献１には、窒化ケイ素（Ｓｉ_３Ｎ_４）またはサイアロン（SIALON）からなる保護管の外表面に、下地層としてモリブデンとホウ化ジルコニウムの混合物または化合物を被覆し、この外側に中間層としてモリブデンとホウ化ジルコニウムとジルコニアの混合物または化合物を被覆し、この中間層の外側に最表面層としてジルコニアを被覆した温度センサが開示されている。 In Patent Document 1, a mixture or a compound of molybdenum and zirconium boride is coated as an underlayer on the outer surface of a protective tube made of silicon nitride (Si ₃ N ₄ ) or sialon (SIALON), and an outer layer is formed as an intermediate layer. A temperature sensor is disclosed in which a mixture or compound of molybdenum, zirconium boride, and zirconia is coated, and zirconia is coated as an outermost layer on the outer side of the intermediate layer.

特許文献２には、高純度アルミナにて保護管を形成するとともに、保護管の周囲を冷却媒体が流れる冷却筒で囲み、更にこの冷却筒に保護管を固定するためのフランジを保護管に形成した温度センサが開示されている。 In Patent Document 2, a protective tube is formed of high-purity alumina, and the protective tube is surrounded by a cooling cylinder through which a cooling medium flows, and a flange for fixing the protective tube to the cooling cylinder is formed in the protective tube. A temperature sensor is disclosed.

特許文献３に開示される温度センサは、窒化ケイ素（Ｓｉ_３Ｎ_４）、サイアロン（SIALON）または炭化ケイ素（ＳｉＣ）にて保護管を構成し、この保護管の先端部を薄く（０．５ｍｍ）して熱容量を小さくし、測温応答性を向上させることが開示され、また保護管の先端部内には窒化ケイ素（Ｓｉ_３Ｎ_４）系反応焼結セラミックからなる充填材を入れて熱電対を固定し、また保護管の後方部分にはＳｉＣウィスカーからなる充填材を配置する構造が開示されている。 In the temperature sensor disclosed in Patent Document 3, a protective tube is made of silicon nitride (Si ₃ N ₄ ), sialon (SIALON), or silicon carbide (SiC), and the tip of the protective tube is thin (0.5 mm). ) To reduce the heat capacity and improve the temperature measurement responsiveness, and in the tip of the protective tube, a filler made of silicon nitride (Si ₃ N ₄ ) -based reaction sintered ceramic is put into a thermocouple. And a structure in which a filler made of SiC whiskers is disposed in the rear portion of the protective tube.

特開２００３−００４５３８号公報JP 2003-004538 A 特開２００４−１２５６４３号公報JP 2004-125643 A 特開平１０−０３０９６７号公報Japanese Patent Laid-Open No. 10-030967

特許文献１に開示されるように、保護管の外側に下地層、中間層、最表面層を被覆すると、保護管の先端部の厚みが増して測温応答性が劣化してしまう。 As disclosed in Patent Document 1, when the base layer, the intermediate layer, and the outermost surface layer are coated on the outer side of the protective tube, the thickness of the tip of the protective tube increases and the temperature measurement responsiveness deteriorates.

また特許文献２に開示されるようにフランジを設ける場合、射出成形では材料が廻り込めないので特許文献２の図に示されるような大きなフランジ部を成形することはできない。 In addition, when a flange is provided as disclosed in Patent Document 2, the material cannot go around by injection molding, and thus a large flange portion as shown in the drawing of Patent Document 2 cannot be formed.

更に特許文献３に開示されるように保護管の先端部を薄肉にすれば、応答性は向上するが、セラミック材料としてアルミナを用いた場合には、先端部の厚みを０．５ｍｍにしても不十分である。
また、特許文献３にあっては充填材として窒化ケイ素（Ｓｉ_３Ｎ_４）系反応焼結セラミックを用いているが、高温と低温の繰り返しや外的衝撃を受けると、保護管内側面と充填材との間に隙間が生じ、応答性が劣化する。 Furthermore, as disclosed in Patent Document 3, if the tip of the protective tube is made thin, the response will be improved. However, if alumina is used as the ceramic material, the thickness of the tip will be 0.5 mm. It is insufficient.
In Patent Document 3, a silicon nitride (Si ₃ N ₄ ) -based reaction sintered ceramic is used as a filler, but when subjected to repeated high and low temperatures and external impact, the inner surface of the protective tube and the filler A gap is formed between them and the response is deteriorated.

上記課題を解決するため本発明に係る温度センサは、保護管をセラミックス製とし、このセラミックス製保護管の先端部を他の部分に比較して薄肉に成形し、この先端部内側には前記一対の金属の結合部を被覆するガラス玉を収納し、このガラス球は伝熱性に優れ且つ柔軟性を有する樹脂充填材にて保持された構成とした。 In order to solve the above-mentioned problems, a temperature sensor according to the present invention has a protective tube made of ceramics, the tip of the ceramic protective tube is formed thinner than the other parts, The glass balls covering the metal joints were housed, and the glass balls were held by a resin filler having excellent heat conductivity and flexibility.

前記セラミックス製保護管は好ましくはアルミナ製であり、先端部の厚みは０．３ｍｍ以下であり、前記伝熱性に優れ且つ柔軟性を有する樹脂はシリコーン樹脂（ＳｉＯ_２）を主体としたものとする。 The protective tube made of ceramic is preferably made of alumina, the tip portion has a thickness of 0.3 mm or less, and the resin having excellent heat conductivity and flexibility is mainly composed of silicone resin (SiO ₂ ). .

また、射出成形にて保護管を一体成形する場合に、必要な厚みと径を持ったフランジ部を形成することが困難な場合には、セラミックス製保護管の外周に射出成形の際に環状凸部を形成し、この環状凸部外側に金属製のフランジを圧入するできる。 If it is difficult to form a flange with the required thickness and diameter when integrally forming the protective tube by injection molding, the outer periphery of the ceramic protective tube is And a metal flange can be press-fitted outside the annular convex portion.

本発明に係る温度センサによれば、先端の感熱部を例えば０．３ｍｍ以下まで薄くしているため、セラミック材料として他のセラミック材料よりも伝熱性に劣るアルミナを用いても、十分な応答性が得られる。 According to the temperature sensor of the present invention, since the heat sensitive part at the tip is thinned to, for example, 0.3 mm or less, sufficient response can be obtained even if alumina having inferior heat conductivity is used as the ceramic material. Is obtained.

また、熱電対を保護管の先端部内に固定する充填材として伝熱性に優れ且つ柔軟性を有する樹脂、例えばシリコーン樹脂を主体としたものを用いることで、外的衝撃及び熱的衝撃に対する耐久性が向上する。 In addition, durability against external and thermal shocks is achieved by using a resin with excellent heat conductivity and flexibility, such as silicone resin, as a filler for fixing the thermocouple in the tip of the protective tube. Will improve.

以下に本発明の実施の形態を添付図面に基づいて説明する。図１は本発明に係る温度センサを組み込んだ温水器の概略図、図２は同温度センサの配管への取り付け状態を示す断面図、図３は同温度センサの先端部の拡大断面図である。 Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a schematic view of a water heater incorporating a temperature sensor according to the present invention, FIG. 2 is a cross-sectional view showing a state in which the temperature sensor is attached to a pipe, and FIG. 3 is an enlarged cross-sectional view of the tip of the temperature sensor. .

温水器は本体カバー１内にバーナ２、配管３、伝熱用フィン４が配置され、配管３の一端から水が供給され、配管３の他端から湯が取り出される。そして、バーナ２よりも下流側の配管３の一部に本発明に係る温度センサ５が取り付けられている。 In the water heater, a burner 2, a pipe 3 and a heat transfer fin 4 are arranged in the main body cover 1, water is supplied from one end of the pipe 3, and hot water is taken out from the other end of the pipe 3. A temperature sensor 5 according to the present invention is attached to a part of the pipe 3 on the downstream side of the burner 2.

前記配管３には図２に示すように開口６が形成され、この開口６の外側面に金属ブロック７が溶接され、この金属ブロック７には前記開口６と２段状の開口８が形成され、これら開口６，８を貫通し且つＯリング９および取付けプレート１０を介して温度センサ５が配管３内に挿入・固定されている。 An opening 6 is formed in the pipe 3 as shown in FIG. 2, and a metal block 7 is welded to the outer surface of the opening 6. The metal block 7 is formed with the opening 6 and a two-stage opening 8. The temperature sensor 5 is inserted and fixed in the pipe 3 through the openings 6 and 8 and through the O-ring 9 and the mounting plate 10.

温度センサ５はアルミナなどのセラミックス製保護管１１内に熱電対２０を装着して構成される。セラミックス製保護管１１は射出成形にて成形され、厚みが一定厚（Ｔ１＝０．４５ｍｍ）の基部１２と、この基部１２に連続するとともに厚みが先端に向かって徐々に薄くなるテーパ部１３と、このテーパ部１３に連続するとともに最も厚み（Ｔ２＝０．３ｍｍ）が薄くなった先端部１４と、前記基部１２とテーパ部１３の境界部付近に設けられるフランジ部１５からなる。 The temperature sensor 5 is configured by mounting a thermocouple 20 in a protective tube 11 made of ceramics such as alumina. The ceramic protective tube 11 is formed by injection molding, and has a base portion 12 having a constant thickness (T1 = 0.45 mm), and a tapered portion 13 that is continuous with the base portion 12 and gradually decreases in thickness toward the tip. The tip portion 14 is continuous with the tapered portion 13 and has the thinnest thickness (T2 = 0.3 mm), and the flange portion 15 is provided near the boundary between the base portion 12 and the tapered portion 13.

前記熱電対２０はＷ−Ｒｅ素線２１，２１と、この素線２１，２１の結合部を被覆するガラス玉２２と、コネクタ２３からなる。 The thermocouple 20 is composed of W-Re strands 21, 21, glass balls 22 covering the connecting portions of the strands 21, 21, and a connector 23.

前記ガラス玉２２はシリコーン樹脂（ＳｉＯ_２）を主体とした充填材２４にて前記セラミックス製保護管１１の先端部１４内に押し込められて固定されている。ここで、シリコーン樹脂（ＳｉＯ_２）を主体とした充填材２４は柔軟性を持つため、押し込む際に先端部１４内側面との間には隙間が形成されず保護管先端部１４の内側に空気が噛み込むことがない。また、且つ熱的・外的衝撃が加えられても隙間は形成されない。尚、充填材２４には伝熱性を高めるため、金属粉などを添加することが考えられる。 The glass ball 22 is fixed by being pushed into the distal end portion 14 of the ceramic protective tube 11 with a filler 24 mainly composed of silicone resin (SiO ₂ ). Here, since the filler 24 mainly composed of silicone resin (SiO ₂ ) has flexibility, no gap is formed between the inner surface of the distal end portion 14 and the air inside the distal end portion 14 of the protective tube when being pushed. Will not bite. Further, no gap is formed even when a thermal / external impact is applied. In addition, in order to improve heat conductivity, it is possible to add metal powder etc. to the filler 24.

また、セラミックス製保護管１１の先端部１４よりも後方部分はウレタンを主体とした充填材２５にて封止されている。 The rear part of the ceramic protective tube 11 is sealed with a filler 25 mainly composed of urethane.

図４乃至図６は別実施例に係る温度センサの断面図であり、このうち図４（ａ）、（ｂ）に示す温度センサは、板状をなす薄膜サーミスタ２８の一面の左右に電極部を形成し、これら電極部に素線２１の先端部を結合している。この温度センサの先端部はサーミスタ２８の形状に合せて偏平に近い形状となっており、幅広の部分の外径寸法は１．３ｍｍ、幅狭の部分の外径寸法は１．１ｍｍにしている。 4 to 6 are cross-sectional views of a temperature sensor according to another embodiment. Among these, the temperature sensor shown in FIGS. 4A and 4B has electrode portions on the left and right sides of one surface of the thin film thermistor 28 having a plate shape. And the tip end of the strand 21 is coupled to these electrode portions. The tip of this temperature sensor has a shape that is almost flat to match the shape of the thermistor 28, the outer diameter of the wide portion is 1.3 mm, and the outer diameter of the narrow portion is 1.1 mm. .

また図５に示す別実施例はフランジ部を一体成形せずに、必要とするフランジ部よりも高さの低い環状凸部２６を一体成形し、この環状凸部２６の外側に金属製のフランジ部材２７を圧入するようにしている。 Further, another embodiment shown in FIG. 5 does not integrally form the flange portion, but integrally forms an annular convex portion 26 having a lower height than the required flange portion, and a metal flange on the outside of the annular convex portion 26. The member 27 is press-fitted.

図６に示す別実施例は、セラミックス製保護管３１は、厚みが一定厚（Ｔ１＝０．４５ｍｍ）の基部３２と、この基部１２に連続するとともに厚み（Ｔ２＝０．１５ｍｍ）が薄くなった先端部３３と、フランジ部３４からなる。
セラミックス製保護管の形状としては上記に限らず、先端部が例えば０．３ｍｍ以下と薄ければよい。また先端部の形状は球面に限らない。 In another embodiment shown in FIG. 6, the protective tube 31 made of ceramic has a base 32 having a constant thickness (T1 = 0.45 mm) and a base 12 that is continuous with the base 12 and a reduced thickness (T2 = 0.15 mm). It consists of a leading end 33 and a flange 34.
The shape of the ceramic protective tube is not limited to the above, and the tip may be thin, for example, 0.3 mm or less. The shape of the tip is not limited to a spherical surface.

本発明に係る温度センサを組み込んだ温水器の概略図Schematic of a water heater incorporating a temperature sensor according to the present invention 同温度センサの配管への取り付け状態を示す断面図Sectional drawing which shows the attachment state to piping of the same temperature sensor 同温度センサの先端部の拡大断面図Enlarged sectional view of the tip of the temperature sensor （ａ）は別実施例に係る温度センサの先端部の拡大断面図、（ｂ）は（ａ）のＢ方向矢視図(A) is an expanded sectional view of the front-end | tip part of the temperature sensor which concerns on another Example, (b) is a B direction arrow directional view of (a). 別実施例に係る温度センサの断面図Sectional drawing of the temperature sensor which concerns on another Example 別実施例に係る温度センサの断面図Sectional drawing of the temperature sensor which concerns on another Example

Explanation of symbols

１…温水器の本体カバー、２…バーナ、３…配管、４…伝熱用フィン、５…温度センサ、６…開口、７…金属ブロック、８…開口、９…Ｏリング、１０…取付けプレート、１１，３１…セラミックス製保護管、１２，３２…セラミックス製保護管の基部、１３…セラミックス製保護管のテーパ部、１４，３３…セラミックス製保護管の先端部、１５，３４…フランジ部、２０…熱電対、２１…熱電対の素線、２２…ガラス玉、２３…コネクタ、２４，２５…充填材、２６…環状凸部、２７…金属製のフランジ部材、２８…薄膜サーミスタ。 DESCRIPTION OF SYMBOLS 1 ... Main body cover of water heater, 2 ... Burner, 3 ... Piping, 4 ... Heat transfer fin, 5 ... Temperature sensor, 6 ... Opening, 7 ... Metal block, 8 ... Opening, 9 ... O-ring, 10 ... Mounting plate 11, 31 ... Ceramic protective tube, 12, 32 ... Base portion of ceramic protective tube, 13 ... Tapered portion of ceramic protective tube, 14, 33 ... Tip portion of ceramic protective tube, 15, 34 ... Flange portion, DESCRIPTION OF SYMBOLS 20 ... Thermocouple, 21 ... Thermocouple strand, 22 ... Glass ball, 23 ... Connector, 24, 25 ... Filler, 26 ... Annular convex part, 27 ... Metal flange member, 28 ... Thin film thermistor.

Claims

In the temperature sensor in which the metal coupling part constituting the thermocouple is held in the ceramic protective tube, the tip of the ceramic protective tube is formed to be thinner than the other parts. A temperature sensor characterized in that glass balls that cover the pair of metal joints are housed, and the glass balls are held by a resin filler having excellent heat conductivity and flexibility.

2. The temperature sensor according to claim 1, wherein the ceramic protective tube is made of alumina, a tip portion has a thickness of 0.3 mm or less, and the resin filler is mainly composed of a silicone resin. Temperature sensor.

2. The temperature sensor according to claim 1, wherein an annular convex portion serving as a flange portion for injection molding is formed on an outer periphery of the ceramic protective tube.

2. The temperature sensor according to claim 1, wherein an annular protrusion is formed on the outer periphery of the ceramic protective tube during injection molding, and a metal flange is press-fitted outside the annular protrusion. Temperature sensor.