JPS59217478A - Frost sensor - Google Patents
Frost sensorInfo
- Publication number
- JPS59217478A JPS59217478A JP8220884A JP8220884A JPS59217478A JP S59217478 A JPS59217478 A JP S59217478A JP 8220884 A JP8220884 A JP 8220884A JP 8220884 A JP8220884 A JP 8220884A JP S59217478 A JPS59217478 A JP S59217478A
- Authority
- JP
- Japan
- Prior art keywords
- frost
- piezoelectric body
- vibrator
- frost sensor
- coefficient
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Defrosting Systems (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
本発明は冷却器の熱交換器に付着する霜を自動的に検出
する霜センサに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frost sensor that automatically detects frost adhering to a heat exchanger of a cooler.
従来の霜センサは第１図に示すように、ベローズ１の内
面に圧電体２を接着剤３にて固定しており、かつベロ−
ズ１は被取付部に取付けるようにしている。この霜検知
の原理は、上記圧電体１に電圧を加えておいて常時、圧
電体１を振動させておく、この状態でベローズ１に霜が
付着すると、圧電体１に対して霜が負荷となり、圧電体
１の共振インピーダンスが増加し、振動が停止すること
を検出して、霜の付着検出を行うわけである。また、ベ
ローズ１の内部には充填材４を詰めて、さらに発熱体５
を設置しており、霜の検知後、前記発熱体５に通電して
、振動部を加熱し、霜や水滴を除去するようにしている
。ここで、６は圧電体２のためのり一ド線、７は発熱体
５のだめの引出しリード線である。As shown in FIG. 1, the conventional frost sensor has a piezoelectric body 2 fixed to the inner surface of a bellows 1 with an adhesive 3, and a bellows 1.
The lens 1 is attached to the part to be attached. The principle of this frost detection is that a voltage is applied to the piezoelectric body 1 and the piezoelectric body 1 is constantly vibrated. If frost adheres to the bellows 1 in this state, the frost becomes a load on the piezoelectric body 1. The adhesion of frost is detected by detecting that the resonance impedance of the piezoelectric body 1 increases and the vibration stops. In addition, the inside of the bellows 1 is filled with a filler 4, and a heating element 5 is also filled.
is installed, and after detecting frost, electricity is applied to the heating element 5 to heat the vibrating section and remove frost and water droplets. Here, 6 is a lead wire for the piezoelectric body 2, and 7 is a lead wire for the heating element 5.
々お、ベロ−ズ１は途中に蛇腹部を設けて、充填材４に
より圧電体２の振動が減衰されないようにしている。Furthermore, the bellows 1 is provided with a bellows part in the middle so that the vibration of the piezoelectric body 2 is not attenuated by the filling material 4.
このように第１図の構成によれば、自動的に霜の検出を
行うことができるものの、次に述べるよな金属を用いな
ければならないが、これらの金属の熱膨張率は１５Ｘ１
０”−６以上であり、一方、圧電体として圧電セラミッ
クを使用した場合、圧電セラミックの熱膨張率は約５Ｘ
１０−６であり、両者の間の熱膨張率は３倍以上の差が
ある。このため、ベローズと圧電セラミックを接着した
場合、冷却時と加熱時の温度差によシ両者の間にひずみ
が生じ、長時間、冷却と加熱を繰り返すと接合状態が劣
化し、共振インピーダンスが増加したり、素子が割れた
シして信頼性が劣化するという問題があった。According to the configuration shown in Figure 1, frost can be detected automatically, but the following metals must be used, and the coefficient of thermal expansion of these metals is 15X1.
0"-6 or more, and on the other hand, when a piezoelectric ceramic is used as the piezoelectric body, the thermal expansion coefficient of the piezoelectric ceramic is approximately 5X
10-6, and there is a difference of more than three times in the coefficient of thermal expansion between the two. For this reason, when a bellows and a piezoelectric ceramic are bonded together, the difference in temperature between cooling and heating causes strain between the two, and repeated cooling and heating for a long period of time deteriorates the bonding state and increases resonance impedance. There was a problem that the reliability deteriorated due to cracking of the device or cracking of the device.
本発明はこれらの問題を解決し、信頼性を向上させよう
とするものである。以下その一実施例を第２図、第３図
を用いて説明する。The present invention attempts to solve these problems and improve reliability. An example of this will be described below with reference to FIGS. 2 and 3.
第２図では圧電体１０と熱膨張率の等しい、あるいは近
似した金属板１１に前記圧電体１０を接着して略矩形状
の平板状に加工した振動子をつくり、この振動子の一端
を支持台１２．に固定し、この状態でリード線１３によ
り振動子を発振回路（図示せず）と接続したわみ振動さ
せる。In FIG. 2, the piezoelectric body 10 is bonded to a metal plate 11 having a coefficient of thermal expansion equal to or similar to that of the piezoelectric body 10 to form a substantially rectangular flat plate-shaped vibrator, and one end of the vibrator is supported. Stand 12. In this state, the vibrator is connected to an oscillation circuit (not shown) by a lead wire 13 and is caused to flexurally vibrate.
この振動状態で、振動子に霜が付着すると振動子の共振
インピーダンスが増加し、この変化によ１
リ１″。”着ｔｔｌｔ６Ｊ°け１６・ＥＥ ！ ＋
７ Ｓ ｙりと熱膨張率の近似した金属として鉄−ニノ
ケル合金、鉄−コバルトーニソケル合金等があり、そし
、一端部を保持するようにしている。なお、この矩形状
によれば、形状も単純であり、コストも安価に出来る。In this vibration state, if frost adheres to the vibrator, the resonant impedance of the vibrator increases, and this change causes
ri1″.”arrivalttlt6J°ke16・EE! +
There are iron-Ninokel alloy, iron-cobalt-Ninokel alloy, etc. as metals having a coefficient of thermal expansion similar to 7Sy, and one end portion is held. In addition, according to this rectangular shape, the shape is simple and the cost can be reduced.
第３図は第２図のように構成された振動子の周辺に近接
してヒータ１４を設置したもので、とのヒータ１４は振
動子に霜が付着し、霜の付着を検出した後、この霜を取
除くだめのものである。このヒータ１４はニクロム線の
ようなヒータ線でも、まだサーミスタのような発熱体で
もよい。FIG. 3 shows a heater 14 installed close to the oscillator constructed as shown in FIG. It is meant to remove this frost. The heater 14 may be a heating wire such as a nichrome wire or a heating element such as a thermistor.
以上説明したように本発明によれば、圧電体の熱膨張率
と略等しい熱膨張率の金属板に前記圧電体を接着してそ
の一端部を支持することにより、接合面の劣化が生じる
ことはなく、信頼性に優れた霜センサを提供することが
できる。As explained above, according to the present invention, by adhering the piezoelectric body to a metal plate having a coefficient of thermal expansion substantially equal to that of the piezoelectric body and supporting one end thereof, deterioration of the joint surface can be avoided. However, it is possible to provide a highly reliable frost sensor.
第１図は従来の霜センサの断面図、第２図は本発明の一
実施例における霜センサの構成を示す図、第３図は本発
明の他の例を示す図である。
１Ｑ・・・・・・圧電体、１１・・・・金属板、１２・
・・・・支持台、１３・・・・・リード線、１４・・・
・・・ヒータ。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名第１
図
第２図
２
Ｍ３図
２FIG. 1 is a sectional view of a conventional frost sensor, FIG. 2 is a diagram showing the configuration of a frost sensor in one embodiment of the present invention, and FIG. 3 is a diagram showing another example of the present invention. 1Q...Piezoelectric body, 11...Metal plate, 12...
...Support stand, 13...Lead wire, 14...
···heater. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 2 M3 Figure 2
Claims (1)
する金属板に前記圧電体を固定して略矩形状の振動子を
形成し、との振動子の一端を支持台にて支持してなる霜
センサ。 （２＞ 振動子に近接してヒータを設置してなる特許
請求の範囲第１項記載の霜センサ。(1) A substantially rectangular vibrator is formed by fixing the piezoelectric body to a metal plate having a coefficient of thermal expansion approximately equal to that of the piezoelectric body, and one end of the vibrator is supported by a support stand. frost sensor. (2> The frost sensor according to claim 1, wherein a heater is installed close to the vibrator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8220884A JPS59217478A (en) | 1984-04-24 | 1984-04-24 | Frost sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8220884A JPS59217478A (en) | 1984-04-24 | 1984-04-24 | Frost sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59217478A true JPS59217478A (en) | 1984-12-07 |
Family
ID=13768001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8220884A Pending JPS59217478A (en) | 1984-04-24 | 1984-04-24 | Frost sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59217478A (en) |
-
1984
- 1984-04-24 JP JP8220884A patent/JPS59217478A/en active Pending
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