JP4081295B2

JP4081295B2 - Expansion valve

Info

Publication number: JP4081295B2
Application number: JP2002128532A
Authority: JP
Inventors: 和彦渡辺; 俊治片山; 智紀志村
Original assignee: Fujikoki Corp
Current assignee: Fujikoki Corp
Priority date: 2002-04-30
Filing date: 2002-04-30
Publication date: 2008-04-23
Anticipated expiration: 2022-04-30
Also published as: JP2003322435A

Description

【０００１】
【発明の属する技術分野】
本発明は空気調和装置、冷凍装置等の冷凍サイクルにおいて、エバポレータに供給される冷媒の流量制御に用いられる膨張弁に関する。
【０００２】
【従来の技術】
この種の膨張弁は、自動車等の空気調和装置の冷凍サイクルにおいて用いられており、図２は、従来幅広く用いられている膨張弁の一例の縦断面図を冷凍サイクルの概略と共に示している。図において、膨張弁１０は、角柱状のアルミ製の弁本体３０には、冷凍サイクルの冷媒管路１１においてコンデンサ５の冷媒出口からレシーバ６を介してエバポレータ８の冷媒入口へと向かう部分に介在される高圧の液相冷媒が通過する高圧側通路となる第１の通路３２及び断熱膨張された気液二相冷媒が流入する低圧側通路となる第３の通路３２’と、冷媒管路１１においてエバポレータ８の冷媒出口からコンプレッサ４の冷媒入口へと向かう部分に介在される低圧冷媒通路となる第２の通路３４とが隔壁３８ｆにより上下に相互に離間して弁本体３０の内部に形成されている。
【０００３】
第１の通路３２と第３の通路３２’との間にはレシーバ６の冷媒出口から供給された液体冷媒を断熱膨張させるためのオリフィス３２ａが形成されている。オリフィス３２ａの入口側つまり第１の通路の上流側には弁座が形成されていて、弁座には上流側から弁部材３２ｃにより支持された球状の弁体３２ｂが配置され、弁体３２ｂと弁部材３２ｃとは溶接により固定されている。弁部材３２ｃは、弁体と弁本体の下部に設けられた圧縮コイルばねの如き付勢手段３２ｄとの間に配置され付勢手段３２ｄの付勢力を弁体３２ｂに伝え、弁体３２ｂは弁座に接近する方向に付勢されている。
【０００４】
レシーバ６からの液冷媒が導入される第１の通路３２は液冷媒の通路となり、入口ポート３２１と、この入口ポート３２１に連続する弁室３５を有する。弁室３５は、オリフィス３２ａと同軸に形成される有底の室であり、プラグ３９によって密閉されており、第１の通路３２はオリフィス３２ａを介して第３の通路３２’に連通し、出口ポート３２２から冷媒管路１１によりエバポレータ８の冷媒入口に接続されている。
【０００５】
さらに、弁本体３０にはエバポレータ８の出口温度に応じて弁体３２ｂに対して駆動力を与えてオリフィス３２ａの開閉を行うために、小径の孔３７とこの孔３７より径が大径の孔３８が第２の通路３４を貫通してオリフィス３２ａと同軸に形成され、弁本体３０の外部の上端には感温駆動部となるパワーエレメント部３６がシール材３６ｍを介して固定されるねじ孔３６１が形成されている。
【０００６】
パワーエレメント部３６は、可撓性のある金属製薄板であるステンレス製のダイアフラム３６ａと、このダイアフラム３６ａを挟んで互いに溶接により密着して設けられ、上記ダイアフラムを一壁面として、その上下に区画された二つの圧力室を形成する第１の圧力室である上部圧力室３６ｂ及び第２の圧力室である下部圧力室６ｃをそれぞれ構成する気密壁となるステンレス製の上カバー３６ｄ及び下カバー３６ｈと、上部圧力室３６ｂにダイアフラム駆動媒体となる所定冷媒を封入するためのめくら栓３６ｉとを備え、下部圧力室３６ｃは、オリフィス３２ａの中心線に対して同心的に形成された均圧孔３６ｅを介して第２の通路３４に連通されている。第２の通路３４には、エバポレータ８からの冷媒蒸気が流れ、通路３４は気相冷媒の通路となり、その気相冷媒の圧力が均圧孔３６ｅを介して下部圧力室３６ｃに負荷されている。また、下カバー３６ｈには、筒状の取付座３６２が形成され、取付座３６２がねじ孔３６１に螺着により取付けられ、弁本体３０に固定されている。
【０００７】
さらに、下部圧力室３６ｃ内にダイアフラム３６ａと当接し、かつ第２の通路３４を貫通して隔壁３８ｆ内の大径の孔３８内に摺動可能に配置されて、エバポレータ８の冷媒出口温度を下部圧力室３６ｃへ伝達すると共に、上部圧力室３６ｂ及び下部圧力室３６ｃの圧力差に伴うダイアフラム３６ａの変位に応じて大径の孔３８内を摺動して駆動力を与えるアルミ製の太延の感温棒３６ｆと、小径の孔３７内に摺動可能に配置されて感温棒３６ｆの変位に応じて弁体３２ｂを付勢手段３２ｄの弾性力に抗して押圧する感温棒３６ｆより細径のステンレス製の作動棒３７ｆからなり、感温棒３６ｆには第１の通路３２と、第２の通路３４との気密性を確保するための密封部材、例えばＯリング３６ｇが備えられている。感温棒３６ｆの上端部３６ｋは、ダイアフラム３６ａの下面に当接されて受け部となり、上記ダイアフラムとの接触面積を得るため径方向に拡大されたストッパ部３６Ｌを有している。ダイアフラム３６ａの変位は感温棒３６ｆを介して弁体３２ｂに伝達され、感温棒３６ｆの上端部３６ｋは下部圧力室３６ｃ内を摺動すべくストッパ部３６Ｌは下カバー３６ｈに支持される。
【０００８】
さらに、感温棒３６ｆの下端部は大径の孔３８の底部にて作動棒３７ｆの上端と当接し、作動棒３７ｆの下端は弁体３２ｂと当接しており、感温棒３６ｆと作動棒３７ｆとで感温駆動棒が構成され、この感温駆動棒がダイアフラム３６ａの変位を弁体３２ｂに伝達する伝達部材となる。
【０００９】
以上のパワーエレメント部３６、感温棒３６及び作動棒３７ｆの構成において、作動棒３７ｆが小径の孔３７内に挿入され、感温棒３６ｆが大径の孔３８内に挿入された後に、下カバー３６ｈの取付座３６２がねじ孔３６１に螺合されることによって固定されて、Ｏリング３６ｍによって下カバー３６ｈと弁本体３０との気密性が確保され、ねじ孔３６１は下カバー３６ｈ及びダイアフラム３６ａと共に、下部圧力室３６ｃを構成する。
【００１０】
したがって、均圧孔３６ｅには、ダイアフラム３６ａの下面から第１の通路３２のオリフィス３２ａまで延出した弁体駆動棒が同心的に配置されていることになる。なお、作動棒３７ｆの部分３７ｅはオリフィス３２ａの内径より細く形成されて、オリフィス３２ａ内を挿通し、冷媒はオリフィス３２ａ内を通過する。
【００１１】
以上の構成において、パワーエレメント部３６の上部圧力室３６ｂ中には所定冷媒がダイアフラム駆動媒体（例えば、冷凍サイクルに使用される冷媒ガスと同じ）として充填されていて、ダイアフラム駆動媒体には第２の通路３４や第２の通路３４に連通されている均圧孔３６ｅに露出された感温棒３６ｆ及びダイアフラム３６ａを介して第２の通路３４を流れているエバポレータ８の冷媒出口からの冷媒の圧力及び温度が伝達される。
【００１２】
上部圧力室３６ｂ中のダイアフラム駆動媒体は上記伝達された温度に対応してガス化し圧力が変化し、ダイアフラム３６ａの上面に負荷する。ダイアフラム３６ａは上記上面に負荷されたダイアフラム駆動ガスの圧力とダイアフラム３６ａの下面に負荷された圧力との差により上下に変位する。ダイアフラム３６ａの中心部の上下への変位は感温駆動棒を介して弁体３２ｂに伝達され弁体３２ｂをオリフィス３２ａの弁座に対して接近または離間させる。この結果、冷媒流量が制御されることとなる。
【００１３】
即ち、エバポレータ８の出口側と接続された第２の通路３４内に感温棒３６ｆが配せれており、エバポレータから送り出される低圧の気相冷媒の温度を上部圧力室３６ｂに伝達するため、その圧力の温度に応じて上部圧力室３６ｂの圧力が変化し、エバポレータ８の出口温度が高いため、つまりエバポレータの熱負荷が増加すると、上部圧力室３６ｂの圧力が高くなり、それに応じて感温棒３６ｆつまり感温駆動棒が下方へ駆動されて弁体３２ｂを下げるため、オリフィス３２ａの開度が大きくなる。これによりエバポレータ８への冷媒の供給量が多くなり、エバポレータ８の温度を低下させる。逆に、エバポレータ８から送り出される冷媒の温度が低下する。つまりエバポレータの熱負荷が減少すると、弁体３２ｂが上記と逆方向に駆動され、オリフィス３２ａの開度が小さくなり、エバポレータへの冷媒の供給量が少なくなり、エバポレータ８の温度を上昇させるのである。
【００１４】
【発明が解決しようとする課題】
ところで、上記従来の膨張弁において、コンプレッサ４の起動によって、低圧冷媒通路３４の圧力低下が急激に生じ、パワーエレメント部３６内の第１圧力室と第２圧力室との差圧が大となり、これによるダイアフラム３６ｋの変位により感温棒３６ｆ及び作動棒３７ｆは下方に駆動されて弁体３２ｂを下げることになり、弁体３２ｂをオリフィス３２ａから離間させ、オリフィス３２ａは全開状態となり、レシーバ６から高圧側通路である第１の通路３２を通ってエバポレータ８に向う冷媒の流量が最大に近い状態となる。このため、上記冷媒がオリフィス３２ａを通過するときに発生する冷媒の流動音が大きく、特に気液二相冷媒では、冷媒の流動音が大きくなるという不具合の生じることがあった。
【００１５】
この発明は、上記事情に鑑みてなされたもので、その目的は、コンプレッサ起動時の膨張弁の低圧冷媒通路の圧力低下を遅延させることにより、オリフィスの全開状態を回避し、冷媒流動音を低減することが可能な膨張弁を提供することにある。
【００１６】
【課題を解決するための手段】
そこで請求項１の膨張弁は、エバポレータに向かう冷媒が通過する高圧側通路及び低圧側通路、上記両通路間を連通するオリフィス、及びエバポレータから送り出される冷媒が通過する低圧冷媒通路を有する弁本体と、上記オリフィスを開閉する弁体と、上記弁本体に装着され、ダイアフラムにより区画された第１の圧力室と第２の圧力室を有し、上記第１の圧力室に所定冷媒が封入されるとともに上記第２の圧力室が上記低圧冷媒通路に連通したパワーエレメントと、上記ダイアフラムの変位により上記弁体を駆動する感温駆動棒と、を備えた膨張弁において、上記弁本体は、上記第２の圧力室と上記低圧冷媒通路とを連通するとともに上記オリフィスに対して同心状に形成された均圧孔と、その周囲に形成された段部とを有し、上記低圧冷媒通路内の圧力変動による上記第１の圧力室の圧力変動を遅延させる遅延手段を設け、該遅延手段は、上記パワーエレメントと上記弁本体の間に装着され、上記第２の圧力室と上記低圧冷媒通路との連通を阻止する阻止部材と、上記弁本体に形成され、上記第２の圧力室と上記低圧冷媒通路とを連通する小穴と、から成り、上記阻止部材は小径部と大径部から成る筒状のもので、上記小径部が上記均圧孔に挿入されるとともに上記大径部が上記段部に当接した状態で上記弁本体に装着され、上記感温駆動棒が上記阻止部材の貫通孔に挿通されるとともに上記感温駆動棒と上記貫通孔との間の隙間をシールするＯリングが設けられ、上記小穴は上記段部に設けられたことを特徴とする。この膨張弁によれば、低圧冷媒通路の圧力低下が小穴により第２圧力室に緩慢に伝達されるので、第１圧力室と第２圧力室との差圧の急激な変化を抑制でき、上記差圧に基づくオリフィスの全開状態を回避でき、オリフィスを通過する冷媒の流量を抑制でき、冷媒流動音を低減できる。
【００１７】
請求項２の膨張弁は、請求項１に記載した膨張弁において、上記小穴は、上記感温駆動棒と略平行に設けられたブリードポートであることを特徴としている。
【００２３】
【発明の実施の形態】
本発明に係る膨張弁の一実施の形態について図面に基づいて説明する。
図１は、膨張弁の一実施の形態を示す断面図であり、冷凍サイクルを省略して示している。
図１において、図２に示す従来の膨張弁とは、基本的構成は同一であり、図２と同一符号は、同一又は均等部分を示し、膨張弁１０’では、弁本体３０は、図２に示す従来例と同様の弁本体が用いられており、基本的にはエバポレータに送り込まれる高圧冷媒が通る高圧側流路３２と低圧側流路３２’との間に形成されたオリフィス３２ａと、上記オリフィス３２ａに上記冷媒の上流側から対向するように配置された球状の弁体３２ｂと、上記弁体を上流側から上記オリフィスに向けて付勢するための付勢手段３２ｄと、上記付勢手段の付勢力を上記弁体３２ｂに伝えるために上記付勢手段と上記弁体との間に配置された弁部材３２ｃと、低圧冷媒通路３４が通るエバポレータから送り出される低圧冷媒圧力の温度に対応して動作するパワーエレメント部３６と、弁体３２ｂとの間に配置される感温棒３６ｆと作動棒３７ｆとからなるオリフィス３２ａ内を挿通する感温駆動棒を設け、上記パワーエレメント部３６の動作に応じて上記感温駆動棒により上記弁体３２ｂを上記オリフィス３２ａに対して接離させるようにしたことにより、オリフィス３２ａを通過する冷媒流量を制御するようになっている。
【００２４】
感温駆動棒は、その上端部３６ｋがパワーエレメント部３６を上部圧力室３６ｂと下部圧力室３６ｃに区画するダイアフラム３６ａの下面に当接される端部が径方向に拡大されたストッパ部３６ｌを有している。ダイアフラム３６ａの変位は感温棒３６ｆを介して弁体３２ｂに伝達され、感温棒３６ｆの上端部３６ｋは下部圧力室３６ｃ内を摺動すべくストッパ部３６ｌは下カバー３６ｈに支持される。
【００２５】
而して、感温棒３６ｆにはカラー部材４０が、例えば圧入により具備されており、カラー部材４０は大径の円板部４０ａとその一方の面から立上がる小径の筒部４０ｂとで一体に、例えばステンレス又はアルミニウム等の金属で形成され、中心に貫通孔４０ｃを有する。貫通孔４０ｃには感温棒３６ｆが挿入され、感温棒３６ｆの外周面との間にはＯリング４０ｄが配置されており、円板部４０ａは、下部圧力室３６ｃと均圧孔３６ｅとの間に形成された弁本体３０の段部３０ａに当接して下部圧力室３６ｃ内に存在し、筒部４０ｂは均圧孔３６ｅ内に挿入されている。
【００２６】
さらに、弁本体３０の段部３０ａには、下部圧力室３６ｃと低圧冷媒通路３４とを連通する小穴、例えばブリードポート３０ｂが感温棒３６ｆと平行に形成されている。
【００２７】
かかる構成によれば、コンプレッサの起動時に低圧冷媒通路３４の圧力低下を生じても、カラー部材４０が下部圧力室３６ｃ内及び均圧孔３６ｅ内に存在するので、低圧冷媒通路３４と下部圧力室３６ｃとの間は、カラー部材４０によりその連通が阻止されると共に、ブリードポート３０ｂを介して低圧冷媒通路３４の圧力低下が下部圧力室３６ｃに伝達されるが、その圧力変化はブリードポート３０ｂによって遅延されて緩慢に下部圧力室３６ｃに伝達されることとなる。したがって、低圧冷媒通路３４の圧力低下に基づく、上部圧力室３６ｂの圧力変動を遅延させて生じさせることになる。この結果、コンプレッサの起動時においても上部圧力室３６ｂと下部圧力室３６ｃとの圧力差の急激な変化に基づく、ダイアフラム３６ａの変位によるオリフィス３２ａの急激な全開状態を回避できることになり、オリフィス３２ａを通過する冷媒の流量を抑制でき、冷媒流動音を低減できる。即ち、カラー部材４０及びブリードポート３０ｂは、コンプレッサの起動時における低圧冷媒通路３４の圧力低下に基づく圧力変動をパワーエレメント３６の下部圧力室３６ｃ及び上部圧力室３６ｂへ遅延させて伝達する手段として作用し、また低圧冷媒通路３４の圧力低下に基づくオリフィス３２ａの急激な全開を回避する手段として作用しているのである。
しかも、図１に示す実施の形態においては、図２に示す従来の膨張弁の構成を大幅に変更することなく、冷媒流動音を低減できるのである。
【００２８】
以上実施の形態について説明したが、本発明は上記形態に限定されるものではなく、本発明の範囲内で種々に変更して実施することができる。即ち、本実施の形態では、図１に示す膨張弁において、カラー部材４０としては、金属製に限らず樹脂製とすることができる。また、本実施の形態では小穴について述べたが、本発明では圧力変動を遅延させて伝達する伝達手段であれば、小穴に限らないのは勿論である。
【００２９】
【発明の効果】
本発明によれば、コンプレッサ起動時における膨張弁の低圧冷媒通路の圧力低下に基づくパワーエレメント内の圧力室の圧力変動を遅延させて生じさせることができ、したがって、オリフィスの急激な全開を回避できるので、冷媒流量を抑制して、冷媒流動音を低減できる。
【図面の簡単な説明】
【図１】本発明の膨張弁の一実施の形態を示す断面図。
【図２】従来の膨張弁の構成を示す断面図。
【符号の説明】
３０弁本体
３０ａ段部
３０ｂブリードポート
３２ａオリフィス
３２ｂ弁体
３４低圧冷媒通路
３６パワーエレメント
３６ａダイアフラム
３６ｂ上部圧力室
３６ｃ下部圧力室
３６Ｅ均圧孔
３６ｆ感温棒
３７ｆ作動棒
４０カラー部材
４０ａ円板部
４０ｂ筒部
４０ｄＯリング[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion valve used for flow control of a refrigerant supplied to an evaporator in a refrigeration cycle such as an air conditioner or a refrigeration apparatus.
[0002]
[Prior art]
This type of expansion valve is used in a refrigeration cycle of an air conditioner such as an automobile, and FIG. 2 shows a longitudinal sectional view of an example of an expansion valve that has been widely used together with an outline of the refrigeration cycle. In the figure, the expansion valve 10 is interposed in a prismatic aluminum valve body 30 at a portion of the refrigerant pipe 11 of the refrigeration cycle from the refrigerant outlet of the condenser 5 to the refrigerant inlet of the evaporator 8 via the receiver 6. A first passage 32 serving as a high-pressure side passage through which the high-pressure liquid-phase refrigerant to be passed, a third passage 32 ′ serving as a low-pressure side passage through which the adiabatic-expanded gas-liquid two-phase refrigerant flows, and the refrigerant pipe 11 , A second passage 34 serving as a low-pressure refrigerant passage interposed in a portion from the refrigerant outlet of the evaporator 8 to the refrigerant inlet of the compressor 4 is formed inside the valve body 30 so as to be separated from each other by a partition wall 38f. ing.
[0003]
An orifice 32a for adiabatic expansion of the liquid refrigerant supplied from the refrigerant outlet of the receiver 6 is formed between the first passage 32 and the third passage 32 ′. A valve seat is formed on the inlet side of the orifice 32a, that is, on the upstream side of the first passage, and a spherical valve body 32b supported by a valve member 32c from the upstream side is disposed on the valve seat, and the valve body 32b and The valve member 32c is fixed by welding. The valve member 32c is disposed between the valve body and an urging means 32d such as a compression coil spring provided at the lower part of the valve body, and transmits the urging force of the urging means 32d to the valve body 32b. It is biased in the direction approaching the seat.
[0004]
The first passage 32 into which the liquid refrigerant from the receiver 6 is introduced serves as a liquid refrigerant passage, and has an inlet port 321 and a valve chamber 35 continuous to the inlet port 321. The valve chamber 35 is a bottomed chamber formed coaxially with the orifice 32a, and is sealed by a plug 39. The first passage 32 communicates with the third passage 32 ′ via the orifice 32a, and the outlet. The port 322 is connected to the refrigerant inlet of the evaporator 8 by the refrigerant pipe 11.
[0005]
Further, in order to open and close the orifice 32a by applying a driving force to the valve body 32b according to the outlet temperature of the evaporator 8 to the valve body 30 to open and close the orifice 32a, a hole having a diameter larger than that of the hole 37 is provided. A screw hole 38 is formed through the second passage 34 and coaxially with the orifice 32a, and a power element portion 36 serving as a temperature-sensitive drive portion is fixed to the upper end outside the valve body 30 via a sealing material 36m. 361 is formed.
[0006]
The power element portion 36 is provided with a stainless steel diaphragm 36a, which is a flexible metal thin plate, and is in close contact with each other by welding with the diaphragm 36a interposed therebetween. The power element portion 36 is partitioned above and below the diaphragm as one wall surface. An upper cover 36d and a lower cover 36h made of stainless steel serving as an airtight wall constituting the upper pressure chamber 36b as a first pressure chamber and the lower pressure chamber 6c as a second pressure chamber, respectively, forming two pressure chambers, The upper pressure chamber 36b is provided with a blind plug 36i for enclosing a predetermined refrigerant serving as a diaphragm drive medium, and the lower pressure chamber 36c has a pressure equalizing hole 36e formed concentrically with respect to the center line of the orifice 32a. To the second passage 34. The refrigerant vapor from the evaporator 8 flows through the second passage 34, and the passage 34 serves as a gas-phase refrigerant passage. The pressure of the gas-phase refrigerant is loaded into the lower pressure chamber 36c through the pressure equalizing hole 36e. . A cylindrical mounting seat 362 is formed on the lower cover 36 h, and the mounting seat 362 is attached to the screw hole 361 by screwing and is fixed to the valve body 30.
[0007]
Further, the lower pressure chamber 36c is in contact with the diaphragm 36a and is slidably disposed in the large-diameter hole 38 in the partition wall 38f through the second passage 34, so that the refrigerant outlet temperature of the evaporator 8 is increased. An aluminum thickened tube that transmits to the lower pressure chamber 36c and slides in the large-diameter hole 38 in accordance with the displacement of the diaphragm 36a due to the pressure difference between the upper pressure chamber 36b and the lower pressure chamber 36c to provide a driving force. The temperature sensing rod 36f is slidably disposed in the small-diameter hole 37 and presses the valve body 32b against the elastic force of the biasing means 32d in accordance with the displacement of the temperature sensing rod 36f. The temperature sensing rod 36f includes a sealing member, such as an O-ring 36g, for ensuring airtightness between the first passage 32 and the second passage 34. ing. The upper end portion 36k of the temperature sensing rod 36f is in contact with the lower surface of the diaphragm 36a to become a receiving portion, and has a stopper portion 36L that is enlarged in the radial direction in order to obtain a contact area with the diaphragm. The displacement of the diaphragm 36a is transmitted to the valve body 32b via the temperature sensing rod 36f, and the upper end portion 36k of the temperature sensing rod 36f is supported by the lower cover 36h so as to slide in the lower pressure chamber 36c.
[0008]
Further, the lower end of the temperature sensing rod 36f is in contact with the upper end of the operating rod 37f at the bottom of the large-diameter hole 38, and the lower end of the operating rod 37f is in contact with the valve body 32b. 37f forms a temperature-sensitive drive rod, and this temperature-sensitive drive rod serves as a transmission member that transmits the displacement of the diaphragm 36a to the valve body 32b.
[0009]
In the configuration of the power element portion 36, the temperature sensing rod 36, and the actuation rod 37f described above, after the actuation rod 37f is inserted into the small diameter hole 37 and the temperature sensing rod 36f is inserted into the large diameter hole 38, The mounting seat 362 of the cover 36h is fixed by being screwed into the screw hole 361, and the air tightness between the lower cover 36h and the valve main body 30 is secured by the O-ring 36m. The screw hole 361 has the lower cover 36h and the diaphragm 36a. In addition, the lower pressure chamber 36c is configured.
[0010]
Accordingly, the valve body drive rod extending from the lower surface of the diaphragm 36a to the orifice 32a of the first passage 32 is concentrically disposed in the pressure equalizing hole 36e. The portion 37e of the operating rod 37f is formed to be thinner than the inner diameter of the orifice 32a and is inserted through the orifice 32a, and the refrigerant passes through the orifice 32a.
[0011]
In the above configuration, the upper pressure chamber 36b of the power element portion 36 is filled with a predetermined refrigerant as a diaphragm driving medium (for example, the same as the refrigerant gas used in the refrigeration cycle), and the diaphragm driving medium has the second refrigerant. Of the refrigerant from the refrigerant outlet of the evaporator 8 flowing through the second passage 34 through the temperature sensing rod 36f and the diaphragm 36a exposed to the pressure equalizing hole 36e communicating with the passage 34 and the second passage 34. Pressure and temperature are transmitted.
[0012]
The diaphragm driving medium in the upper pressure chamber 36b is gasified in accordance with the transmitted temperature, the pressure changes, and is loaded on the upper surface of the diaphragm 36a. The diaphragm 36a is displaced up and down by the difference between the pressure of the diaphragm driving gas loaded on the upper surface and the pressure loaded on the lower surface of the diaphragm 36a. The vertical displacement of the central portion of the diaphragm 36a is transmitted to the valve body 32b via the temperature-sensitive driving rod, and the valve body 32b is moved toward or away from the valve seat of the orifice 32a. As a result, the refrigerant flow rate is controlled.
[0013]
That is, a temperature sensing rod 36f is arranged in the second passage 34 connected to the outlet side of the evaporator 8, and the temperature of the low-pressure gas-phase refrigerant sent from the evaporator is transmitted to the upper pressure chamber 36b. Since the pressure in the upper pressure chamber 36b changes according to the temperature of the pressure and the outlet temperature of the evaporator 8 is high, that is, when the heat load of the evaporator increases, the pressure in the upper pressure chamber 36b increases, and the temperature sensing rod accordingly. 36f, that is, the temperature sensitive drive rod is driven downward to lower the valve body 32b, so that the opening of the orifice 32a is increased. As a result, the amount of refrigerant supplied to the evaporator 8 increases and the temperature of the evaporator 8 is lowered. On the contrary, the temperature of the refrigerant sent out from the evaporator 8 decreases. That is, when the evaporator thermal load decreases, the valve body 32b is driven in the opposite direction, the opening of the orifice 32a decreases, the amount of refrigerant supplied to the evaporator decreases, and the temperature of the evaporator 8 increases. .
[0014]
[Problems to be solved by the invention]
By the way, in the conventional expansion valve, when the compressor 4 is started, the pressure drop in the low-pressure refrigerant passage 34 abruptly occurs, and the differential pressure between the first pressure chamber and the second pressure chamber in the power element portion 36 becomes large, Due to the displacement of the diaphragm 36k, the temperature sensing rod 36f and the actuation rod 37f are driven downward to lower the valve body 32b, the valve body 32b is separated from the orifice 32a, the orifice 32a is fully opened, and the receiver 6 The flow rate of the refrigerant toward the evaporator 8 through the first passage 32 that is the high-pressure side passage is close to the maximum. For this reason, the flow noise of the refrigerant generated when the refrigerant passes through the orifice 32a is large. In particular, in the case of a gas-liquid two-phase refrigerant, there is a problem that the flow noise of the refrigerant becomes large.
[0015]
The present invention has been made in view of the above circumstances, and its purpose is to delay the pressure drop of the low-pressure refrigerant passage of the expansion valve when the compressor is started, thereby avoiding the fully open state of the orifice and reducing the refrigerant flow noise. An object of the present invention is to provide an expansion valve that can be used.
[0016]
[Means for Solving the Problems]
Accordingly, an expansion valve according to claim 1 includes a valve main body having a high-pressure side passage and a low-pressure side passage through which refrigerant toward the evaporator passes, an orifice communicating between the two passages, and a low-pressure refrigerant passage through which refrigerant sent from the evaporator passes. And a valve body that opens and closes the orifice, a first pressure chamber and a second pressure chamber that are mounted on the valve body and defined by a diaphragm, and a predetermined refrigerant is sealed in the first pressure chamber. And an expansion valve comprising: a power element in which the second pressure chamber communicates with the low-pressure refrigerant passage; and a temperature-sensitive drive rod that drives the valve body by displacement of the diaphragm . a pressure equalizing hole formed concentrically with respect to said orifice communicated with the second pressure chamber and the said low-pressure refrigerant passage, and a stepped portion formed around said low pressure Delay means for delaying pressure fluctuation in the first pressure chamber due to pressure fluctuation in the medium passage is provided, and the delay means is mounted between the power element and the valve body, and the second pressure chamber and the valve a blocking member for blocking the communication between the low pressure refrigerant passage is formed in the valve body, a small hole for communicating the said second pressure chamber and the low pressure refrigerant passage, formed Ri from the blocking member small diameter portion and the large A cylindrical portion having a diameter portion, wherein the small diameter portion is inserted into the pressure equalizing hole and the large diameter portion is in contact with the stepped portion, and is attached to the valve body, and the temperature sensitive drive rod is An O-ring that is inserted through the through hole of the blocking member and seals the gap between the temperature-sensitive driving rod and the through hole is provided, and the small hole is provided in the stepped portion . According to this expansion valve, since the pressure drop in the low-pressure refrigerant passage is slowly transmitted to the second pressure chamber through the small hole, it is possible to suppress a rapid change in the differential pressure between the first pressure chamber and the second pressure chamber. The fully open state of the orifice based on the differential pressure can be avoided, the flow rate of the refrigerant passing through the orifice can be suppressed, and the refrigerant flow noise can be reduced.
[0017]
An expansion valve according to a second aspect of the present invention is the expansion valve according to the first aspect, wherein the small hole is a bleed port provided substantially in parallel with the temperature-sensitive drive rod .
[0023]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an expansion valve according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of an expansion valve, with the refrigeration cycle omitted.
1, the basic configuration is the same as that of the conventional expansion valve shown in FIG. 2, the same reference numerals as those in FIG. 2 denote the same or equivalent parts, and in the expansion valve 10 ′, the valve body 30 is the same as that in FIG. A valve body similar to the conventional example shown in FIG. 2 is used, and basically an orifice 32a formed between a high-pressure side passage 32 and a low-pressure side passage 32 ′ through which a high-pressure refrigerant sent to the evaporator passes, A spherical valve body 32b disposed so as to face the orifice 32a from the upstream side of the refrigerant, a biasing means 32d for biasing the valve body from the upstream side toward the orifice, and the biasing Corresponding to the temperature of the low-pressure refrigerant pressure sent out from the evaporator through which the low-pressure refrigerant passage 34 and the valve member 32c arranged between the urging means and the valve body in order to transmit the urging force of the means to the valve body 32b Power A temperature sensing rod that is inserted through an orifice 32a composed of a temperature sensing rod 36f and an actuating rod 37f disposed between the ment portion 36 and the valve body 32b. Since the valve body 32b is brought into contact with and separated from the orifice 32a by the temperature sensitive drive rod, the flow rate of the refrigerant passing through the orifice 32a is controlled.
[0024]
The temperature-sensitive driving rod has a stopper portion 36l whose upper end portion 36k is in contact with the lower surface of the diaphragm 36a that divides the power element portion 36 into an upper pressure chamber 36b and a lower pressure chamber 36c, and is radially expanded. Have. The displacement of the diaphragm 36a is transmitted to the valve body 32b via the temperature sensing rod 36f, and the stopper 36l is supported by the lower cover 36h so that the upper end portion 36k of the temperature sensing rod 36f slides in the lower pressure chamber 36c.
[0025]
Thus, the temperature sensing rod 36f is provided with a collar member 40 by, for example, press-fitting, and the collar member 40 is integrally formed by a large-diameter disk portion 40a and a small-diameter cylinder portion 40b rising from one surface thereof. For example, it is made of a metal such as stainless steel or aluminum and has a through hole 40c in the center. A temperature sensing rod 36f is inserted into the through hole 40c, and an O-ring 40d is disposed between the outer circumferential surface of the temperature sensing rod 36f. The disc portion 40a includes a lower pressure chamber 36c, a pressure equalizing hole 36e, and the like. The cylinder body 40b is inserted into the pressure equalizing hole 36e and is in the lower pressure chamber 36c in contact with the step 30a of the valve body 30 formed therebetween.
[0026]
Further, a small hole that communicates the lower pressure chamber 36c and the low pressure refrigerant passage 34, for example, a bleed port 30b, is formed in the step portion 30a of the valve body 30 in parallel with the temperature sensing rod 36f.
[0027]
According to such a configuration, even if the pressure of the low pressure refrigerant passage 34 is reduced when the compressor is started, the collar member 40 exists in the lower pressure chamber 36c and the pressure equalizing hole 36e. 36c is prevented from communicating with the collar member 40, and the pressure drop in the low-pressure refrigerant passage 34 is transmitted to the lower pressure chamber 36c via the bleed port 30b. Delayed and slowly transmitted to the lower pressure chamber 36c. Therefore, the pressure fluctuation in the upper pressure chamber 36b based on the pressure drop in the low-pressure refrigerant passage 34 is delayed and generated. As a result, even when the compressor is started, a sudden fully open state of the orifice 32a due to the displacement of the diaphragm 36a based on a sudden change in the pressure difference between the upper pressure chamber 36b and the lower pressure chamber 36c can be avoided. The flow rate of the refrigerant passing therethrough can be suppressed, and the refrigerant flow noise can be reduced. That is, the collar member 40 and the bleed port 30b act as a means for delaying and transmitting the pressure fluctuation based on the pressure drop in the low-pressure refrigerant passage 34 when the compressor is started to the lower pressure chamber 36c and the upper pressure chamber 36b of the power element 36. In addition, it acts as a means for avoiding sudden full opening of the orifice 32a due to the pressure drop in the low-pressure refrigerant passage 34.
Moreover, in the embodiment shown in FIG. 1, the refrigerant flow noise can be reduced without significantly changing the configuration of the conventional expansion valve shown in FIG. 2.
[0028]
Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. That is, in the present embodiment, in the expansion valve shown in FIG. 1, the collar member 40 is not limited to metal but can be made of resin. Further, although the small hole has been described in the present embodiment, it is needless to say that the present invention is not limited to the small hole as long as it is a transmission means that transmits the pressure fluctuation with a delay.
[0029]
【The invention's effect】
According to the present invention, it is possible to delay the pressure fluctuation in the pressure chamber in the power element based on the pressure drop in the low-pressure refrigerant passage of the expansion valve at the time of starting the compressor. Therefore, the refrigerant flow noise can be reduced by suppressing the refrigerant flow rate.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of an expansion valve of the present invention.
FIG. 2 is a cross-sectional view showing a configuration of a conventional expansion valve.
[Explanation of symbols]
30 Valve body 30a Step portion 30b Bleed port 32a Orifice 32b Valve body 34 Low pressure refrigerant passage 36 Power element 36a Diaphragm 36b Upper pressure chamber 36c Lower pressure chamber 36E Pressure equalizing hole 36f Temperature sensing rod 37f Actuating rod 40 Color member 40a Disc portion 40b Tube part 40d O-ring

Claims

A high-pressure side passage and a low-pressure side passage through which the refrigerant toward the evaporator passes, an orifice communicating between the two passages, a valve body having a low-pressure refrigerant passage through which the refrigerant sent from the evaporator passes, and a valve body for opening and closing the orifice And a first pressure chamber and a second pressure chamber mounted on the valve main body and partitioned by a diaphragm, and a predetermined refrigerant is sealed in the first pressure chamber and the second pressure chamber is In an expansion valve comprising: a power element that communicates with a low-pressure refrigerant passage; and a temperature-sensitive drive rod that drives the valve body by displacement of the diaphragm.
The valve body has a pressure equalizing hole communicating with the second pressure chamber and the low-pressure refrigerant passage and formed concentrically with the orifice, and a step portion formed around the pressure equalizing hole. Delay means for delaying pressure fluctuation in the first pressure chamber due to pressure fluctuation in the low-pressure refrigerant passage is provided, and the delay means is mounted between the power element and the valve body, and the second pressure chamber a blocking member for blocking the communication between the low-pressure refrigerant passage and is formed in the valve body, a small hole for communicating the said second pressure chamber and the low pressure refrigerant passage, formed Ri from the blocking member small diameter portion And the large-diameter portion, and the small-diameter portion is inserted into the pressure equalizing hole and the large-diameter portion is attached to the valve body in contact with the stepped portion. The rod is inserted through the through hole of the blocking member and the temperature sensitive Dobo and the O-ring for sealing a gap between the through-hole is provided, the small hole expansion valve, characterized in that provided in the stepped portion.

2. The expansion valve according to claim 1 , wherein the small hole is a bleed port provided substantially parallel to the temperature-sensitive drive rod .