JP2002062207A - Capacitance type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in a capacitance type pressure sensor used for an electronic hemodynamometer, wherein a solder chip melted by a hot blast for joining a diaphragm and a movable electrode plate is scattered and sticked a solder ball to the diaphragm at soldering time to cause adverse influence on the quality of a sensor due to a change in mass and springiness of the diaphragm. SOLUTION: Soldering to the diaphragm 12 and the movable electrode plate 13 is disused, and both parts are joined by resistance welding. In the drawing, a part 17 is a spot welding part. Thus, the solder chip is not required to reduce a material cost, and scattering and sticking of the solder ball are eliminated to improve the quality. Since there is no need to apply the hot blast, a housing material may not be a thermosetting resin but a thermoplastic resin so that there is an effect of reducing a manufacturing cost.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は電子血圧計等に用い
るのに適する静電容量型圧力センサに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type pressure sensor suitable for use in an electronic sphygmomanometer or the like.

【０００２】[0002]

【従来の技術】図３に電子血圧計の構成図の一例を示
す。腕帯１は袋状で、空気を送って膨らますことができ
るもので、ゴム管２を経て根元管３につながっている。
根元管３にはスローリーク弁４、ポンプ５、電磁弁６、
センサ７等が設けられており、これらは電源、ＣＰＵ、
メモリー、操作ボタン等を含む制御部８に接続されてい
る。もっともポンプとしては、ゴム球を手で圧して加圧
する構造も広く行われている。電磁弁６は排気用である
が、これを手動にしたものもある。2. Description of the Related Art FIG. 3 shows an example of a configuration diagram of an electronic sphygmomanometer. The arm band 1 has a bag shape and can be inflated by sending air, and is connected to a root tube 3 via a rubber tube 2.
Slow leak valve 4, pump 5, solenoid valve 6,
A sensor 7 and the like are provided, and these are a power supply, a CPU,
It is connected to a control unit 8 including a memory, operation buttons, and the like. However, as a pump, a structure in which a rubber ball is pressed by hand and pressurized is widely used. Although the solenoid valve 6 is for exhaust, there is also a valve in which this is manually operated.

【０００３】測定に際しては、腕帯１を腕に巻き付け
て、所定の圧力までポンプ５で腕帯１に空気を送って膨
らませ、血管を圧迫して拍動を停止させた後、スローリ
ーク弁６より空気を少しずつ逃がして徐々に減圧し、そ
れに伴って血管の拍動が回復して行くのに伴う圧力の変
動をセンサ７で検出し、最高と最低の血圧を判定して液
晶等を用いた表示部９に表示する。血圧の判定について
はコロトコフ法、オシロメトリック法などの方式がある
が、詳述は省く。In measurement, the arm band 1 is wrapped around the arm, air is blown to the arm band 1 by the pump 5 to a predetermined pressure to inflate the band, the blood vessel is pressed to stop pulsation, and then the slow leak valve 6 The air is released little by little and the pressure is gradually reduced, and the fluctuation of the pressure accompanying the recovery of the pulsation of the blood vessels is detected by the sensor 7, and the highest and lowest blood pressures are determined, and the liquid crystal or the like is used. Is displayed on the display unit 9. Although there are methods such as Korotkoff method and oscillometric method for determination of blood pressure, detailed description is omitted.

【０００４】図４はこのような電子血圧計に用いるセン
サ７の具体的な例であって、静電容量型の圧力センサで
あり、（Ａ）は平面図、（Ｂ）は（Ａ）のＢ−Ｂ断面図
である。樹脂製のハウジング１１に、燐青銅などの弾性
材料のダイヤフラム１２が固定してある。ダイヤフラム
１２は所要のばね性を得るため、断面に波形部１２ａを
設けてある。金属の可動電極板１３を中央部のＡ領域で
ダイヤフラム１１に接合して一体化してあり、これに対
向して固定電極板１４を配置し、その三つの脚部１４ａ
を電極ピン１５でハウジング１１に固定してある。FIG. 4 shows a specific example of a sensor 7 used in such an electronic sphygmomanometer, which is a capacitance type pressure sensor. FIG. 4A is a plan view, and FIG. It is BB sectional drawing. A diaphragm 12 made of an elastic material such as phosphor bronze is fixed to a resin housing 11. The diaphragm 12 is provided with a corrugated portion 12a in a cross section in order to obtain a required spring property. A metal movable electrode plate 13 is joined to and integrated with the diaphragm 11 at a central region A, and a fixed electrode plate 14 is disposed opposite to the fixed electrode plate 13 and its three legs 14a.
Are fixed to the housing 11 with the electrode pins 15.

【０００５】ハウジング１１の空気通路１６から圧力空
気が矢印のように入ってダイヤフラム１２を圧し、圧力
が低いとダイヤフラム１２はあまり変位しないので、可
動電極板１３と固定電極板１４の間隔ｄは大きく、２枚
の電極板間の静電容量は小さい。圧力が上がるとダイヤ
フラム１２が上方に膨らんで電極板間の間隔ｄが小さく
なり、静電容量が大きくなる。血管の拍動による空気圧
の変化はこのようにセンサの静電容量の変化となって、
図３の制御部８の電気回路により検出される。[0005] Pressurized air enters from the air passage 16 of the housing 11 as shown by the arrow and presses the diaphragm 12, and when the pressure is low, the diaphragm 12 is not displaced much, so that the distance d between the movable electrode plate 13 and the fixed electrode plate 14 is large. And the capacitance between the two electrode plates is small. When the pressure increases, the diaphragm 12 expands upward, the distance d between the electrode plates decreases, and the capacitance increases. The change in air pressure due to the pulsation of the blood vessel results in a change in the capacitance of the sensor,
It is detected by the electric circuit of the control unit 8 in FIG.

【０００６】[0006]

【発明が解決しようとする課題】図４の静電容量型圧力
センサでは、ダイヤフラム１２と可動電極板１３を半田
付けで接合し、導通させている。それにはダイヤフラム
１２をハウジング１１に固定した後、半田の円柱型小片
である半田チップをダイヤフラム１２と可動電極板１３
の間に挟んで、熱風発生ヒーターからの熱風を当てて溶
融させることにより、両部品をＡ領域で接合する。ここ
で問題なのは、溶融した半田が熱風に吹き飛ばされて微
細な半田ボールとなって飛散してダイヤフラム１２に付
着し、これがダイヤフラム１２の質量やばね特性に影響
して、空気圧の変化によるダイヤフラム１２の動きすな
わちセンサの性能を変化させ、品質不具合を生じること
である。本発明はこの問題を解決して、性能の安定した
静電容量型圧力センサを廉価に提供する。In the capacitance type pressure sensor shown in FIG. 4, the diaphragm 12 and the movable electrode plate 13 are joined to each other by soldering to make them conductive. After fixing the diaphragm 12 to the housing 11, a solder chip, which is a small cylindrical piece of solder, is applied to the diaphragm 12 and the movable electrode plate 13.
The two parts are joined in the region A by being sandwiched between them and being melted by applying hot air from a hot air generating heater. The problem here is that the melted solder is blown off by the hot air to form fine solder balls and scatter and adhere to the diaphragm 12, which affects the mass and spring characteristics of the diaphragm 12 and changes the air pressure of the diaphragm 12 due to a change in air pressure. It changes the movement, that is, the performance of the sensor, and causes a quality defect. The present invention solves this problem and provides an inexpensive capacitive pressure sensor with stable performance.

【０００７】[0007]

【課題を解決するための手段】上記の目的のため、本発
明ではダイヤフラム１２と可動電極板１３の接合を半田
付けによらず、抵抗溶接によって行う。これにより半田
材料を使用しなくなるので、半田ボールの飛散、付着が
なくなる。For the above purpose, in the present invention, the connection between the diaphragm 12 and the movable electrode plate 13 is performed not by soldering but by resistance welding. This eliminates the use of a solder material, so that the solder balls are not scattered or adhered.

【０００８】[0008]

【発明の実施の形態】図１に本発明の実施形態の一つを
示す。図４のような静電容量型圧力センサからダイヤフ
ラム１２と可動電極板１３を抜き出して図示したもの
で、両部品を中央部の点溶接部１７で接合してある。作
業としては、両部品を重ねて二つの溶接電極で上下から
挟んで加圧し、通電して溶接する。これにより両部品が
結合され、電気的導通も確保される。FIG. 1 shows one embodiment of the present invention. The diaphragm 12 and the movable electrode plate 13 are extracted from the capacitance type pressure sensor as shown in FIG. 4 and are shown in the drawing. Both parts are joined by a central spot welding portion 17. In operation, both parts are overlapped, sandwiched between two welding electrodes from above and below, pressurized, energized and welded. As a result, the two parts are connected, and electrical conduction is also ensured.

【０００９】ダイヤフラム１２と可動電極板１３を溶接
して一体にしたものを、図４（Ｂ）のようにハウジング
１１に取り付けてもいいが、まずダイヤフラム１２をハ
ウジング１１に固定してから、ダイヤフラム１２と可動
電極板１３を重ねて溶接することもできる。その場合、
ダイヤフラム１２側の溶接電極はハウジング１１の空気
通路１６から差し込んでダイヤフラム１２に押し当て
る。The diaphragm 12 and the movable electrode plate 13 which are integrated by welding may be attached to the housing 11 as shown in FIG. 4B. First, the diaphragm 12 is fixed to the housing 11 and then the diaphragm is fixed. 12 and the movable electrode plate 13 can be overlapped and welded. In that case,
The welding electrode on the side of the diaphragm 12 is inserted from the air passage 16 of the housing 11 and pressed against the diaphragm 12.

【００１０】図２のように、ダイヤフラム１２と可動電
極板１３の一方または両方の接合面の中央部に絞り加工
やコイニングで１２ｂ、１３ａで示すような突起を設
け、点溶接の際に電流がこの部分に集中するようにして
もよい。As shown in FIG. 2, projections such as 12b and 13a are provided at the center of one or both of the joining surfaces of the diaphragm 12 and the movable electrode plate 13 by drawing or coining so that a current is applied at the time of spot welding. You may concentrate on this part.

【００１１】以上、静電容量型圧力センサを電子血圧計
に用いた実施形態について説明したが、静電容量型圧力
センサの用途が電子血圧計に限るものでないことはいう
までもない。Although the embodiment in which the capacitance type pressure sensor is used for the electronic sphygmomanometer has been described above, it goes without saying that the application of the capacitance type pressure sensor is not limited to the electronic sphygmomanometer.

【００１２】[0012]

【発明の効果】静電容量型圧力センサにて、ダイヤフラ
ムと可動電極板を半田付けでなく抵抗溶接で接合する構
造により、本発明は次のような効果を有する。 １．半田材料が不要となって費用が削減される。 ２．半田ボールが飛散してダイヤフラムに付着すること
がなくなり、品質や性能が向上する。 ３．従来、半田を融かすのに熱風を当てていたため、ハ
ウジング材料は熱硬化性樹脂でなければならなかった
が、抵抗溶接の採用により熱可塑性樹脂でよくなり製作
費が低減する。 このように本発明によれば、高品質で低価格の静電容量
型圧力センサが得られる。The present invention has the following effects by a structure in which a diaphragm and a movable electrode plate are joined by resistance welding instead of soldering in a capacitance type pressure sensor. 1. No solder material is required, and costs are reduced. 2. Solder balls are not scattered and adhere to the diaphragm, so that quality and performance are improved. 3. Conventionally, since hot air was blown to melt the solder, the housing material had to be a thermosetting resin. However, adoption of resistance welding reduces the manufacturing cost by using a thermoplastic resin. As described above, according to the present invention, a high-quality and low-cost capacitive pressure sensor can be obtained.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明にてダイヤフラムと可動電極板を接合し
た状態である。FIG. 1 shows a state in which a diaphragm and a movable electrode plate are joined according to the present invention.

【図２】本発明にてダイヤフラムと可動電極板に突起を
設けて接合した状態である。FIG. 2 shows a state in which projections are provided on the diaphragm and the movable electrode plate and joined together according to the present invention.

【図３】電子血圧計の構成図の一例である。FIG. 3 is an example of a configuration diagram of an electronic sphygmomanometer.

【図４】従来の静電容量型圧力センサの一例で、（Ａ）
は上面図、（Ｂ）は（Ａ）のＢ−Ｂ断面図である。FIG. 4 shows an example of a conventional capacitance type pressure sensor, (A)
Is a top view, and (B) is a BB sectional view of (A).

【符号の説明】[Explanation of symbols]

１１ ハウジング １２ ダイヤフラム １２ａ 波形部 １２ｂ 突起 １３ 可動電極板 １３ａ 突起 １４ 固定電極板 １４ａ 脚部 １５ 電極ピン １６ 空気通路 １７ 点溶接部 DESCRIPTION OF SYMBOLS 11 Housing 12 Diaphragm 12a Wave part 12b Projection 13 Movable electrode plate 13a Projection 14 Fixed electrode plate 14a Leg 15 Electrode pin 16 Air passage 17 Point welding part

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 ダイヤフラムに接合した可動電極板とこ
れに対向する固定電極板をハウジングに収容してなる静
電容量型圧力センサにおいて、 ダイヤフラムと可動電極板を抵抗溶接により接合したこ
とを特徴とする静電容量型圧力センサ。1. A capacitance type pressure sensor in which a movable electrode plate joined to a diaphragm and a fixed electrode plate facing the movable electrode plate are housed in a housing, wherein the diaphragm and the movable electrode plate are joined by resistance welding. Capacitive pressure sensor. 【請求項２】 請求項１に記載の静電容量型圧力センサ
において、 ダイヤフラムと可動電極板の接合面の一方または両方に
突起を設けたことを特徴とする静電容量型圧力センサ。2. The capacitance type pressure sensor according to claim 1, wherein a projection is provided on one or both of a joining surface of the diaphragm and the movable electrode plate.