JP4380045B2

JP4380045B2 - Rotary multistage compressor

Info

Publication number: JP4380045B2
Application number: JP2000279677A
Authority: JP
Inventors: 勝晴藤尾; 秀夫平野; 雄一薬丸
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-09-14
Filing date: 2000-09-14
Publication date: 2009-12-09
Anticipated expiration: 2020-09-14
Also published as: JP2002089472A

Description

【０００１】
【発明の属する技術分野】
本発明はロータリ式多段圧縮機の給油手段に関するものである。
【０００２】
【従来の技術】
昨今の地球環境保護問題に端を発して、従来から継続使用されているフロン冷媒に替わり自然冷媒、特に、二酸化炭素（ＣＯ２）冷媒を用いたヒートポンプシステムの研究開発が各分野で盛んに行われている。
【０００３】
しかしながら、従来のフロン冷媒を用いた冷凍サイクルでは、高圧側が３ＭＰａ以下であるのに対して、二酸化炭素（ＣＯ２）冷媒を用いた冷凍サイクルでは、低圧側が２．５〜５ＭＰａ，高圧側が１２〜１５ＭＰａにも達して高低圧力差が極めて大きく、圧縮機シリンダ内での圧縮途中気体漏れ損失の過大が懸念されている。
【０００４】
このような理由から、二酸化炭素（ＣＯ２）冷媒を用いた圧縮機として、従来からの多段圧縮機の改良検討が進められている。
【０００５】
特に、家庭用ヒートポンプシステムに搭載される圧縮機としては、生産性と耐久性および小型化の観点からロータリ式２段圧縮機が注目を浴びている。二酸化炭素（ＣＯ２）冷媒を用いた圧縮機は高圧側圧力が高いことから、安全性と摺動部への給油性および圧縮効率を鑑みて、電動機を収納する密閉容器内を、吸入圧力と吐出圧力との中間圧力にする構成が適していることが知られている。
【０００６】
このような電動機を収納する密閉容器内を中間圧力にする構成は、例えば、特開昭５０−７２２０５号公報で代表される。更には特開平２−２９４５８６号公報、特開平２−２９４５８７号公報などでも提案されている。図７は特開平２−２９４５８７号公報で示されたフロン冷媒を使用するローリングピストン型ロータリ式２段圧縮機の縦断面図、図８は同圧縮機の横断面図である。
【０００７】
図７、図８において１００１は密閉容器、１００２は密閉容器１００１内に設けられた電動機部、１００３は電動機部１００２の下に位置する１段目シリンダー（低段側シリンダブロック）、１００４は１段目シリンダー（低段側シリンダブロック）１００３の下方に位置する２段目シリンダー（高段側シリンダブロック）、１００５は密閉容器１００１に固定され１段目シリンダー（低段側シリンダブロック）１００３と２段目シリンダー（高段側シリンダブロック）１００４に挟まれた中板である。１００６は２段目シリンダー（高段側シリンダブロック）１００４の下に位置する下軸受端板（副軸受）、１００７は電動機部１００２と圧縮機部とを連結しているクランク軸（駆動軸）、１００８は１段目シリンダー（低段側シリンダブロック）１００３内で動く１段目ピストン（低段ピストン）、１００９は２段目シリンダー（高段側シリンダブロック）１００４内で動く２段目ピストン（高段ピストン）、１０１０は平板（高段吐出カバー）である。１０１１は１段目吸入管（低段吸入管）、１０１２は２段目吐出冷媒を直接、密閉容器１の外に出す２段目吐出管である。１０１３は２段目ベーン（高段ベーン）、１０１４は２段目ベーン（高段ベーン）１０１３を押さえているベーンバネ、１０１５は、２段目ベーン（高段ベーン）１０１３、中板１００５、下軸受端板（副軸受）１００６および２段目のシリンダーベーン溝により密閉容器１００１内の冷媒と密閉隔離されたベーン背面室（高段背面室）１０１６は下軸受端板（副軸受）１００６、平板（高段吐出カバー）１０１０に囲まれた２段目吐出弁室（高段吐出室）、１０１７はベーン背面室（高段背面室）１０１５と２段目吐出弁室（高段吐出室）１０１６を連通している導入路である。
【０００８】
このような構成において、２段目吐出弁室（高段吐出室）１０１６の吐出冷媒ガスの一部は、導入路１０１７を介してベーン背面室（高段背面室）１０１５に導かれて、ベーンバネと共に２段目ベーン（高段ベーン）１０１３の先端を２段目ピストン（高段ピストン）１００９に適正な力で押付け、シリンダ内空間を吸入側と圧縮側とに仕切る構成である。
【０００９】
【発明が解決しょうとする課題】
しかしながらこのような構成では、ベーン背面室（高段背面室）１０１５の吐出冷媒ガスが２段目ベーン（高段ベーン）１０１３の摺動部微小隙間を通して圧縮室に漏洩流入するので、圧縮効率が著しく低下すると共に、２段目ベーン（高段ベーン）１０１３の摺動部微小隙間への給油不足から２段目ベーン（高段ベーン）１０１３の耐久性確保が困難であるという課題があった。
【００１０】
本発明はこのような従来の課題を解決するものであり、高段側ベーン背面室への潤滑油供給確保を図ることを目的とするものである。
【００１１】
【課題を解決するための手段】
上記課題を解決するために本発明は、高段（最終段）吐出側の油溜と高段側（最終段）ベーン背面室とを連通して、高段側（最終段）ベーン背面室への十分な潤滑油供給通路の確保を図るものである。
【００１２】
上記高段側（最終段）ベーン背面室への十分な潤滑油供給通路の確保によって、シリンダ内圧縮空間への吐出冷媒ガスの流入を防止し、圧縮効率とベーン耐久性を向上できる。
【００１３】
【発明の実施の形態】
請求項１に記載の発明は、密閉容器内に複数の圧縮要素を順次直列接続した多段圧縮機構と多段圧縮機構の駆動軸に連結する電動機とを収納し、圧縮要素の各シリンダ内を出没（前進・後退）しつつ吸入室と圧縮室とに区画する各ベーンの内の最終段圧縮要素の最終段ベーンの最終段背面室と最終段圧縮要素の最終段吐出側とを連通する一方、最終段圧縮要素を除く圧縮要素の各ベーンの背面室に、最終段圧縮要素を除く各圧縮要素の吐出相当圧力の潤滑油を導入すると共に、密閉容器内を前段圧縮要素の吐出相当圧力以下の気体で充満させた構成において、最終段圧縮要素に隣接した最終段吐出室の底部の油溜と最終段背面室とを連通したものである。そしてこの構成によれば、最終段吐出圧力が作用する潤滑油を最終段背面室に供給してベーンの摺動面に給油し、摺動部における油膜形成によって最終段背面室からシリンダ内への気体漏洩を防止できる。また、最終段吐出室で最終段吐出気体から分離した潤滑油を簡単且つ効率良く流下させ最終段背面室に供給できる。
【００１４】
請求項２に記載の発明は、最終段吐出室が、駆動軸を支持すべく多段圧縮機構に配置され且つ最終段圧縮要素の吐出口を備えた軸受と、最終段背面室の開口部とを囲む様態で形成されたものである。そしてこの構成によれば、吐出口から排出した吐出気体から分離した潤滑油が軸受外周底部の油溜に効率良く収集され、油溜の一部を兼ねる最終背面室への十分な給油ができる。
【００１５】
請求項３に記載の発明は、吐出口を開閉する吐出弁装置を収納すべく軸受に凹設された吐出弁室の吐出口側を最終段背面室の開口部の方向に向けものである。そしてこの構成によれば、吐出気体と共に排出された潤滑油を効率良く最終背面室に供給できる。
【００１６】
請求項４に記載の発明は、密閉容器内空間から隔離して最終段吐出室を形成すべく軸受と最終段背面室の開口部とを囲む様態で最終段圧縮要素のシリンダに固定された吐出カバ
ーを密閉容器に固定したものである。そしてこの構成によれば、密閉容器内空間から隔離した最終段吐出室の形成と多段圧縮機構の密閉容器への固定とを同時に実現できる。
【００１７】
請求項５に記載の発明は、最終段吐出室から圧縮機外部への吐出気体排出通路の最上流通路が油溜とは反対側の前記最終段吐出室の上面壁に向かって突出開口して配置されたものである。そしてこの構成によれば、圧縮機外部への排出気体による油溜の潤滑油最巻き込みを少なくすることができる。
【００１８】
請求項６に記載の発明は、密閉容器内に複数の圧縮要素を順次直列接続した多段圧縮機構と前記多段圧縮機構の駆動軸に連結する電動機とを収納し、前記圧縮要素の各シリンダ内を出没（前進・後退）しつつ吸入室と圧縮室とに区画する各ベーンの内の最終段圧縮要素の最終段ベーンの最終段背面室と前記最終段圧縮要素の最終段吐出側とを連通する一方、前記最終段圧縮要素を除く前記圧縮要素の前記各ベーンの背面室に、前記最終段圧縮要素を除く前記各圧縮要素の吐出相当圧力の潤滑油を導入すると共に、密閉容器内を初段圧縮要素の吸入相当圧力の気体で充満させ、最終段背面室の潤滑油を順次・前段背面室に減圧流入させる給油通路を設けたものである。そしてこの構成によれば、耐圧容器としての圧縮機の安全性を確保すると共に、圧縮機外部への潤滑油吐出量を少なくし、各ベーンの背面室の潤滑油不足を防ぎ、潤滑油膜の有効活用を図ることができる。
【００１９】
請求項７に記載の発明は、初段背面室と密閉容器内との間を絞り通路で連通させたものである。そしてこの構成によれば、圧縮機外部への潤滑油吐出量を少なくし、圧縮機内の潤滑油不足を防ぎ、圧縮機耐久性を向上できる。
【００２０】
【実施例】
以下本発明の実施例について図面を参照して説明する。
【００２１】
（実施例１）
図１は二酸化炭素冷媒を使用したローリングピストン型ロータリ式２段圧縮機の縦断面を表し、図２は図１における２段圧縮機構部の部分縦断面を表し、図３は図２の部分詳細を表し、図４は図２におけるＡ−Ａ線に沿った横断面を表す。
【００２２】
密閉容器１の内部に、電動機２とその下部に２段圧縮機構３が配置されている。２段圧縮機構３は、高段（最終段）圧縮要素４と、その下部に配置された低段（初段）圧縮要素５と、高段（最終段）圧縮要素４および低段（初段）圧縮要素５の間に配置された中板６と、高段（最終段）圧縮要素４および低段（初段）圧縮要素５を駆動すべく電動機２の回転子２ａに連結された駆動軸７と、駆動軸７を支持すべく高段（最終段）圧縮要素４の高段（最終段）側シリンダブロック８に固定された主軸受９および低段（初段）圧縮要素５の低段（初段）側シリンダブロック１０に固定された副軸受１１とから成る。
【００２３】
高段（最終段）側シリンダブロック８に固定され且つその外周部が密閉容器１に溶接固定された高段（最終段）吐出カバー１２は、主軸受９のシリンダブロック取付フランジ部９ａを囲み且つ軸受本体９ｂの外周部を囲む様態で配置されて高段（最終段）吐出室１３を形成している。高段（最終段）吐出室１３の底部は油溜１４を形成し、高段（最終段）ベーン１５の反圧縮室側に形成された高段（最終段）背面室１６に常時連通している。
【００２４】
高段（最終段））背面室１６のベーンバネ装着穴１７の終端は高段（最終段）側シリンダブロック８に圧入されたメクラ栓１８によって封止されている。高段（最終段）背面室１６と密閉容器１の内部とは、メクラ栓１８に設けられた絞り機能を有する油戻し通路１８ａにより連通している。
【００２５】
高段（最終段）吐出室１３は、主軸受９のシリンダブロック取付フランジ部９ａに立ち上げ固定された排出管１９を経由し且つ密閉容器１の側壁を貫通して形成された吐出冷媒ガス排出通路２０によって圧縮機外部吐出配管系２１に通じている。
【００２６】
主軸受９に設けられた高段（最終段）圧縮要素４の圧縮室に開口する吐出口２２は、シリンダブロック取付フランジ部９ａに凹設された吐出弁室２３に取付られた吐出弁装置２４によって開閉される。吐出弁室２３の吐出口側端は、圧縮室から吐出冷媒ガスと共に吐出口２２から排出した潤滑油が高段（最終段）背面室１６に流入容易なように、高段（最終段）背面室１６に向かって配置されている。
【００２７】
副軸受１１と共に低段（初段）側シリンダブロック１０に固定された低段（初段）吐出カバー２６は、副軸受１１と共に低段（初段）吐出室２７を形成する。低段（初段）吐出室２７は、副軸受１１と低段（初段）シリンダブロック１０と中板６と高段（最終段）シリンダブロック８と高段（最終段）吐出カバー１２を順次連通して形成された中間ガス通路２８を経由して電動機２が収納されている電動機室２９に通じている。
【００２８】
中間ガス通路２８の終端は、高段（最終段）吐出カバー１２に装着された放出管２９によって電動機２のコイルエンド２ｃに接近している。放出管２９とは反対側位置のコイルエンド２ｃの近傍に開口する中間連通管３０が密閉容器１の側壁を貫通している。
【００２９】
中間ガス通路２８の途中から分岐して接続された中間通路連通管３１が密閉容器１の側壁を貫通している。
【００３０】
密閉容器１の底部の油溜３２と電動機室２９との間は、高段（最終段）吐出カバー１２に設けられた油落とし穴３３を介して連通している。
【００３１】
低段（初段）圧縮要素５の低段（初段）背面室３３は、ベーンバネ装着穴３４を介して油溜３２に連通している。低段（初段）圧縮要素５の吸入側通路は副軸受１１に設けられた極細孔３５を介して油溜３２に連通している。
【００３２】
以上のように構成された二酸化炭素冷媒ガスを使用したローリングピストン型ロータリ式２段圧縮機について、その動作を説明する。
【００３３】
密閉容器１の側壁を貫通する低段（初段）吸入管３６を通じて低段（初段）圧縮要素５のシリンダ内に取り込まれた冷媒ガスは副軸受１１に設けられた極細孔３５を通じて油溜３２から減圧導入された潤滑油を混入状態で圧縮された後、低段（初段）吐出室２７に排出され、電動機室２９と中間連通管３１に分流排出される。
【００３４】
電動機室２９に流入した冷媒ガスは、コイルエンド２ｃに衝突する。その際に、冷媒ガスに混入する潤滑油が分離される。その後、冷媒ガスはコイルエンド２ｃの内外側面を１８０度迂回して中間連通管３０から排出する。この冷媒ガスのコイルエンド２ｃの内外側面流れによって冷媒ガスに混入する潤滑油が分離されると共に、電動機２が冷却される。
【００３５】
一方、中間連通管３１から排出された冷媒ガスは、熱交換器（図示なし）を介して空気（２段圧縮機が空調機に使用される場合）または水（２段圧縮機が給湯機に使用される場合）と熱交換して冷却された後、中間連通管３０から排出した冷媒ガスと合流の後、密閉容器１の側壁を貫通した高段（最終段）吸入管３７を介して高段（最終段）圧縮要素４のシリンダ内に取り込まれる。冷媒ガスと共に中間連通管３１を通じて高段（最終段）圧縮要素４のシリンダ内に取り込まれた潤滑油は、圧縮室の微小隙間の油膜密封作用に供され、冷媒ガスと圧縮の後、吐出口２２から高段（最終段）吐出室１３に排出される。
【００３６】
吐出口２２から排出された冷媒ガスの一部は、吐出弁室２３に沿って高段（最終段）背面室１６の方向に流れ、高段（最終段）吐出カバー１２の内壁面に衝突し、冷媒ガスに混入する潤滑油が分離され、高段（最終段）背面室１６に流入する。吐出口２２から排出された残りの冷媒ガスは、高段（最終段）吐出カバー１２の内壁面全域と衝突し、冷媒ガスから分離した潤滑油が主軸受９のシリンダブロック取り付けフランジ部９ａの外周囲の油溜１４に収集された後、高段（最終段）背面室１６に流入する。
【００３７】
高段（最終段）背面室１６の潤滑油は、高段（最終段）ベーン１５の往復運動によってポンプ作用を受けて油溜１４に出入りするが、潤滑油の一部は高段（最終段）ベーンの摺動部隙間を通して高段（最終段）圧縮要素４のシリンダ内に差圧流入する一方、メクラ栓１８に設けた油戻し通路１８ａを介して油溜３２に減圧流入する。
【００３８】
排出管１９を通じて高段（最終段）吐出室１３から圧縮機外部に排出された吐出冷媒ガスは、油分離器（図示なし）を通して潤滑油を分離される。油分離器の潤滑油は、減圧された後、密閉容器１の側壁を貫通して配置された油戻し管３８を介して油溜３２に戻される。
【００３９】
以上のように上記実施例によれば、密閉容器１内に低段（初段）圧縮要素５と高段（最終段）圧縮要素４を直列接続した２段圧縮機構３とその２段圧縮機構３の駆動軸７に連結する電動機２とを収納し、各圧縮要素４，５の各シリンダ内を出没（前進・後退）しつつ吸入室と圧縮室とに区画する各ベーンの内の高段（最終段）圧縮要素４の高段（最終段）ベーン１５の高段（最終段）背面室１６と高段（最終段）吐出室１３とを連通する一方、低段（初段）圧縮要素５の低段（初段）ベーンの低段（初段）背面室３３に、低段（初段）圧縮要素５の吐出圧力が作用する電動機室２９の油溜３２の潤滑油を導入した構成において、高段（最終段）圧縮要素４の高段（最終段）吐出室１３とその下部の高段（最終段）背面室１６とを連通したことにより、高段（最終段）吐出圧力が作用する潤滑油を高段（最終段）背面室１６に供給して高段（最終段）ベーン１５の摺動面に給油し、摺動部における油膜形成によって高段（最終段）ベーン１５の摺動部摩擦抵抗の低減と摺動部隙間を密封し、高段（最終段）ベーン１５の耐久性向上並びに高段（最終段）背面室１６からシリンダ内への吐出気体漏洩防止による圧縮効率向上を図ることができる。
【００４０】
また上記実施例によれば、高段（最終段）圧縮要素４に隣接した高段（最終段）吐出室１３の底部の油溜１４とその下部位置に配置した高段（最終段）背面室１６とを連通したことにより、高段（最終段）吐出室１３で高段（最終段）吐出気体から分離した潤滑油を短い経路で簡単且つ効率良く高段（最終段）背面室１６に効率良く確実に供給し、高段ベーン１５の耐久性並びに圧縮効率の一層の向上を図ることができる。
【００４１】
また上記実施例によれば、高段（最終段）吐出室１３は、駆動軸７を支持すべく２段圧縮機構３に配置され且つ高段（最終段）圧縮要素４の吐出口２２を備えた主軸受９と、高段（最終段）背面室１５の開口部とを囲む様態で形成されたことにより、吐出口２２から排出した吐出気体から分離した潤滑油が主軸受９のシリンダブロック取付フランジ部９ａの外周底部の油溜１４に効率良く収集され、高段（最終段）背面室１６への十分な給油を行い、高段（最終段）ベーン１５の耐久性並びに圧縮効率の一層の向上を図ることができる。
【００４２】
また上記実施例によれば、高段（最終段）背面室１６に供給された潤滑油を減圧して低段（初段）圧縮要素５の低段（初段）ベーンの低段（初段）背面室３３とに通じる電動機室２９に供給する油戻し通路１８ａを形成したことにより、高段（最終段）吐出側に吐出気体と共に排出された潤滑油の圧縮機外部への排出量を少なくし、圧縮機内潤滑油確保に
よる圧縮機信頼性向上と、冷凍サイクル配管系における熱交換効率を向上できる。
【００４３】
また上記実施例によれば、吐出口２２を開閉する吐出弁装置２４を収納すべく主軸受９に凹設された吐出弁室２３の吐出口側を高段（最終段）背面室１６の開口部の方向に向けて配置したことにより、吐出気体と共に排出された潤滑油を効率良く高段（最終段）背面室１６に供給し、高段（最終段）ベーン１５の耐久性並びに圧縮効率の一層の向上を図ることができる。
【００４４】
また上記実施例によれば、低段（初段）吐出気体が充満した密閉容器１内空間から隔離して高段（最終段）吐出室１３を形成すべく主軸受９と高段（最終段）背面室１６の開口部とを囲む様態で高段（最終段）側シリンダブロック８に固定された高段（最終段）吐出カバー１２を密閉容器１に固定したことにより、密閉容器１内空間から隔離した高段（最終段）吐出室１３の形成と２段圧縮機構３の密閉容器１への固定とを同時に行い、圧縮機信頼性向上とコスト低減ができる。
【００４５】
また上記実施例によれば、高段（最終段）吐出室１３から圧縮機外部への吐出気体排出通路の最上流通路が油溜１４とは反対側の高段（最終段）吐出室１３の上面壁に向かって突出開口して配置されたことにより、圧縮機外部への排出気体による油溜の潤滑油最巻き込みを少なくし、圧縮機内潤滑油確保による圧縮機信頼性向上と、冷凍サイクル配管系における熱交換効率を向上できる。
【００４６】
（実施例２）
図５は上記実施例１における高段（最終段）背面室と圧縮機外部吐出配管系に配置された油分離器（図示なし）の油溜との間を逆止弁装置５１を介して連通した構成である。
【００４７】
すなわち、高段（最終段）吐出室１３の油溜１４に連通する高段（最終段）背面室１６ｂの終端を塞ぐメクラ栓１８ｂには、圧縮機外部の油分離器（図示なし）からの油戻し管５２が連通している。高段（最終段）背面室１６ｂと油溜３２との間は、高段（最終段）側シリンダブロック８ｂに設けた絞り通路（図示なし）を介して連通している。その他の構成は、実施例１の場合と同様である。
【００４８】
このような構成において、高段（最終段）ベーン１５がシリンダ中心側に向かう前進行程の時（シリンダ内への吸入気体容積が拡大行程にある時）、高段（最終段）背面室１６ｂは高段（最終段）ベーン１５の往復運動に起因するポンプ作用における吸入行程の状態である。このタイミングにおいて、圧縮機外部の油分離器（図示なし）から潤滑油が高段（最終段）背面室１６ｂに導入される。
【００４９】
高段（最終段）ベーン１５がシリンダ中心側から離れる後退行程の時（シリンダ内での圧縮行程が進行している時）、高段（最終段）背面室１６ｂは高段（最終段）ベーン１５の往復運動に起因するポンプ作用における排出行程の状態である。このタイミングにおいて、高段（最終段）背面室１６ｂは逆止弁装置５１の逆止作用によって圧縮機外部の油分離器（図示なし）への連通が遮断される。
【００５０】
圧縮機運転停止後は、圧縮機外部の油分離器（図示なし）から自重によって潤滑油が高段背面室１６ｂに戻される。
【００５１】
上記実施例によれば、密閉容器１ｂ内を低段（初段）圧縮要素５の吐出圧力気体で充満させた構成において、高段（最終段）圧縮要素４の吐出側に設けた油分離器（図示なし）の油溜と高段（最終段）背面室１６ｂとを逆止弁装置５１を介して油戻し管５２により連通したことにより、圧縮機外部に排出した潤滑油を高段（最終段）ベーン１５の摺動部潤
滑に有効活用し、高段（最終段）ベーン１５の耐久性向上並びに高段（最終段）背面室１６ｂからシリンダ内への吐出気体漏洩防止による圧縮効率向上を図ることができる。
【００５２】
（実施例３）
図６は、実施例１における密閉容器内を吸入気体圧力で充満させた構成を示す。
【００５３】
すなわち、密閉容器１ｃの側壁を吸入管６１が貫通して電動機室２９ｃに通じている。電動機２のコイルエンド２ｃに近接開口して配置された低段（初段）吸入管３６ｃが低段（初段）圧縮要素５ｃの吸入側に連通している。
【００５４】
高段（最終段）圧縮要素４ｃの高段（最終段）背面室１６ｃの終端はメクラ栓１８ｃによって閉塞されている。低段（初段）圧縮要素５ｃの低段（初段）背面室３３ｃは、低段（初段）背面室３３ｃの終端に配置されたメクラ栓６４に設けた絞り通路６３を介して、電動機室２９ｃの底部の油溜３２ｃに連通している。高段（最終段）背面室１６ｃと低段（初段）背面室３３ｃとは、中板６ｃに設けた絞り通路６２を介して連通している。その他の構成は、実施例１の場合と同様である。
【００５５】
このような構成において、冷凍サイクルの吸入側から吸入管６１を介して電動機室２９ｃに流入した冷媒ガスは、コイルエンド２ｃに衝突する。この際に、冷媒ガス中に混入する潤滑油が分離し油溜３２ｃに収集する。その後、冷媒ガスは低段（初段）吸入管３６ｃを経て低段（初段）圧縮要素５ｃのシリンダ内に取り込まれ、圧縮される。
【００５６】
油溜３２ｃの油面高さが高くなると、余分な潤滑油が吸入冷媒ガスと共に低段（初段）吸入管から吸い込まれ、圧縮室微小隙間の油膜密封と摺動部潤滑に供される。
【００５７】
高段（最終段）吐出室で吐出冷媒ガスから分離した潤滑油は、高段（最終段）背面室１６ｃに流入後、中板６ｃに設けた絞り通路６２を経由して減圧され、低段（初段）背面室３３ｃに供給される。低段（初段）背面室３３ｃの潤滑油は、更に絞り通路６３を経由して減圧され、油溜３２ｃに戻される。
【００５８】
上記実施例によれば、密閉容器１ｃ内に低段（初段）圧縮要素５ｃと高段（最終段）圧縮要素４ｃを直列接続した２段圧縮機構３ｃとその駆動軸７に連結する電動機２とを収納し、各圧縮要素４ｃ，５ｃの各シリンダ内を出没（前進・後退）しつつ吸入室と圧縮室とに区画する各ベーンの内の高段（最終段）圧縮要素４ｃの高段（最終段）ベーン１５の高段（最終段）背面室１６ｃと高段（最終段）吐出室１３とを連通する一方、低段（初段）圧縮要素５ｃの低段（初段）背面室３３ｃに、高段（最終段）背面室１６ｃの潤滑油を低段吐出圧力まで減圧供給すると共に、最終段圧縮要素を除く各圧縮要素の吐出相当圧力の潤滑油を導入すると共に、密閉容器１ｃ内を低段（初段）圧縮要素５ｃの吸入圧力気体で充満させたことにより、密閉容器１ｃの耐圧力を低くして圧力容器としての圧縮機の耐圧・気密の信頼性を確保することができる。
【００５９】
また上記実施例によれば、高段（最終段）吐出室１３で吐出冷媒ガスから分離した潤滑油を高段（最終段）背面室１６ｃを経由して低段（初段）圧縮要素５ｃの低段（初段）背面室３３ｃに供給の後、低段（初段）圧縮要素５ｃの吸入圧力気体で充満させた密閉容器１ｃ内に油戻しすることにより、圧縮機外部への潤滑油吐出量を少なくし、圧縮機内の潤滑油不足を防ぎ、潤滑油膜の有効活用による摺動部耐久性の向上と、圧縮室隙間密封による圧縮効率向上を図ることができる。
【００６０】
なお、上記実施例では２段圧縮機について説明したが、各圧縮要素を順次・直列接続して、３段圧縮、４段圧縮など多段圧縮機構に展開できる。
【００６１】
また、上記実施例２では圧縮機外部吐出配管系に配置した油分離器の油溜を高段（最終段）背面室に接続したが、高段（最終段）背面室への給油が充分確保できる場合は、低段（初段）背面室に絞り通路を介して連通しても良く、逆止弁装置を不要にできる。
【００６２】
なお、上記実施例では二酸化炭素冷媒を使用したローリングピストン型ロータリ式２段圧縮機について説明したが、他の気体（例えば、酸素，窒素，ヘリウム，空気など）を圧縮する２段ローリングピストン型ロータリ式圧縮機の場合も同様な作用・効果を生じるものである。
【００６３】
また、上記実施例では実施例１〜実施例３について個別に説明したが、２段圧縮機の運転条件や圧縮負荷条件などによって、実施例１〜実施例３の構成を適宜組み合わせることにより、一層の高効率・耐久性に優れた２段圧縮機を実現することができる。
【００６４】
また、上記実施例では縦置き形圧縮機について説明したが、ベーンの背面室を圧縮機底部に配置した構成の横置き形ローリングピストン型ロータリ式２段圧縮機についても類似構成によって、上記同様の作用効果が期待できる。この横置き形構成では、高段吐出室を電動機側に配置した主軸受と、電動機から離れた副軸受側とのいずれかの側に配置することができる。
【００６５】
【発明の効果】
上記実施例から明かなように、請求項１に記載の発明は、密閉容器内に複数の圧縮要素を順次直列接続した多段圧縮機構と多段圧縮機構の駆動軸に連結する電動機とを収納し、圧縮要素の各シリンダ内を出没（前進・後退）しつつ吸入室と圧縮室とに区画する各ベーンの内の最終段圧縮要素の最終段ベーンの最終段背面室と最終段圧縮要素の最終段吐出側とを連通する一方、最終段圧縮要素を除く圧縮要素の各ベーンの背面室に、最終段圧縮要素を除く各圧縮要素の吐出相当圧力の潤滑油を導入すると共に、密閉容器内を前段圧縮要素の吐出相当圧力以下の気体で充満させた構成において、最終段圧縮要素に隣接した最終段吐出室の底部の油溜とそれよりも下部に設けた最終段背面室とを連通したもので、この構成によれば、最終段吐出圧力が作用する潤滑油を最終段背面室に供給してベーンの摺動面に給油し、摺動部における油膜形成によって最終段ベーンの摺動部摩擦抵抗の低減と摺動部隙間を密封し、最終段ベーンの耐久性向上並びに最終段背面室からシリンダ内への吐出気体漏洩防止による圧縮効率向上を図ることができる。また、最終段吐出室で最終段吐出気体から分離した潤滑油を簡単且つ効率良く流下させ最終段背面室に供給できる。
【００６６】
請求項２に記載の発明は、最終段吐出室が、駆動軸を支持すべく多段圧縮機構に配置され且つ最終段圧縮要素の吐出口を備えた軸受と、最終段背面室の開口部とを囲む様態で形成されたもので、この構成によれば、吐出口から排出した吐出気体から分離した潤滑油が軸受外周底部の油溜に効率良く収集され、油溜の一部を構成する最終段背面室への十分な給油が容易にできるので、最終段ベーンの耐久性並びに圧縮効率の一層の向上を図ることができる。
【００６７】
請求項３に記載の発明は、吐出口を開閉する吐出弁装置を収納すべく軸受に凹設された吐出弁室の吐出口側を最終段背面室の開口部の方向に向けたもので、この構成によれば、吐出気体と共に排出された潤滑油を効率良く最終背面室に供給できるので、最終段ベーンの耐久性並びに圧縮効率の一層の向上を図ることができる。
【００６８】
請求項４に記載の発明は、密閉容器内空間から隔離して最終段吐出室を形成すべく軸受と最終段背面室の開口部とを囲む様態で最終段圧縮要素のシリンダに固定された吐出カバーを密閉容器に固定したもので、この構成によれば、密閉容器内空間から隔離した最終段
吐出室の形成と多段圧縮機構の密閉容器への固定とを同時に実現できるので、圧縮機信頼性向上とコスト低減ができる。
【００６９】
請求項５に記載の発明は、最終段吐出室から圧縮機外部への吐出気体排出通路の最上流通路が油溜とは反対側の前記最終段吐出室の上面壁に向かって突出開口して配置されたもので、この構成によれば、圧縮機外部への排出気体による油溜の潤滑油最巻き込みを少なくすることができるので、圧縮機内潤滑油確保による圧縮機信頼性向上と、冷凍サイクル配管系における熱交換効率を向上できる。
【００７０】
請求項６に記載の発明は、密閉容器内に複数の圧縮要素を順次直列接続した多段圧縮機構と前記多段圧縮機構の駆動軸に連結する電動機とを収納し、前記圧縮要素の各シリンダ内を出没（前進・後退）しつつ吸入室と圧縮室とに区画する各ベーンの内の最終段圧縮要素の最終段ベーンの最終段背面室と前記最終段圧縮要素の最終段吐出側とを連通する一方、前記最終段圧縮要素を除く前記圧縮要素の前記各ベーンの背面室に、前記最終段圧縮要素を除く前記各圧縮要素の吐出相当圧力の潤滑油を導入すると共に、密閉容器内を初段圧縮要素の吸入相当圧力の気体で充満させ、最終段背面室の潤滑油を順次・前段背面室に減圧流入させる給油通路を設けたもので、この構成によれば、密閉容器の耐圧力を低くして耐圧容器としての圧縮機の安全性を確保すると共に、密閉容器の薄肉化による軽量化とコスト低減ができる。また、圧縮機外部への潤滑油吐出量を少なくし、各ベーンの背面室の潤滑油不足を防ぎ、潤滑油膜の有効活用を図ることができる。
【００７１】
請求項７に記載の発明は、初段背面室と密閉容器内との間に絞り通路で連通させたもので、この構成によれば、圧縮機外部への潤滑油吐出量を少なくできるので、圧縮機内の潤滑油不足を防ぎ、潤滑油膜の有効活用による摺動部耐久性の向上と、圧縮室隙間密封による圧縮効率を向上できるという効果を奏する。
【図面の簡単な説明】
【図１】本発明の一実施例を示すローリングピストン型ロータリ式２段圧縮機の縦断面図
【図２】同圧縮機における圧縮機構部の部分断面図
【図３】同圧縮機構部の部分詳細図
【図４】図１におけるＡ−Ａ線に沿った横断面図
【図５】別の実施例におけるローリングピストン型ロータリ式２段圧縮機の部分縦断面図
【図６】更に別の実施例におけるローリングピストン型ロータリ式２段圧縮機の部分縦断面図
【図７】従来のローリングピストン型ロータリ式２段圧縮機の縦断面図
【図８】同圧縮機のＢ−Ｂ線に沿った横断面図
【符号の説明】
１密閉容器
１ｃ密閉容器
２電動機
３２段圧縮機構
３ｃ２段圧縮機構
４高段（最終段）圧縮要素
４ｃ高段（最終段）圧縮要素
５低段（初段）圧縮要素
５ｃ低段（初段）圧縮要素
７駆動軸
８高段（最終段）側シリンダブロック
９主軸受
１２高段（最終段）吐出カバー
１３高段（最終段）吐出室
１４油溜
１５高段（最終段）ベーン
１６高段（最終段）背面室
１６ｂ高段（最終段）背面室
１６ｃ高段（最終段）背面室
１８ａ油戻し通路
２２吐出口
２３吐出弁室
２４吐出弁装置
２９電動機室
３２油溜
３３低段（初段）背面室
３３ｃ低段（初段）背面室
５１逆止弁装置
５２油戻し管[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an oil supply means of a rotary multistage compressor.
[0002]
[Prior art]
  Rising from recent global environmental protection problems, research and development of heat pump systems using natural refrigerants, especially carbon dioxide (CO2) refrigerants, in place of CFC refrigerants that have been used continuously has been actively conducted in various fields. ing.
[0003]
  However, in the refrigeration cycle using the conventional chlorofluorocarbon refrigerant, the high pressure side is 3 MPa or less, whereas in the refrigeration cycle using the carbon dioxide (CO2) refrigerant, the low pressure side is 2.5 to 5 MPa and the high pressure side is 12 to 15 MPa. Therefore, the pressure difference between the high and low is extremely large, and there is a concern about excessive gas leakage loss during compression in the compressor cylinder.
[0004]
  For these reasons, improvement studies of conventional multistage compressors are being promoted as compressors using carbon dioxide (CO2) refrigerant.
[0005]
  In particular, as a compressor mounted in a home heat pump system, a rotary type two-stage compressor is attracting attention from the viewpoint of productivity, durability, and downsizing. Since the compressor using carbon dioxide (CO2) refrigerant has a high pressure on the high pressure side, the suction pressure and the discharge in the sealed container that houses the motor are taken into consideration in view of safety, oil supply to the sliding part and compression efficiency. It is known that an intermediate pressure with respect to the pressure is suitable.
[0006]
  Such a configuration in which the inside of a sealed container that houses an electric motor is set to an intermediate pressure is represented by, for example, Japanese Patent Laid-Open No. 50-72205. Further, JP-A-2-294586, JP-A-2-294877, and the like have also been proposed. FIG. 7 is a longitudinal sectional view of a rolling piston type rotary two-stage compressor using a chlorofluorocarbon refrigerant disclosed in Japanese Patent Laid-Open No. 2-294857, and FIG. 8 is a transverse sectional view of the compressor.
[0007]
  7 and 8, reference numeral 1001 denotes a sealed container, 1002 denotes an electric motor unit provided in the sealed container 1001, 1003 denotes a first-stage cylinder (low-stage side cylinder block) positioned below the electric motor part 1002, and 1004 denotes one-stage. A second-stage cylinder (high-stage side cylinder block) 1005 positioned below the second-stage cylinder (low-stage side cylinder block) 1003 is fixed to the hermetic container 1001, and a first-stage cylinder (low-stage side cylinder block) 1003 and two-stage An intermediate plate sandwiched between eye cylinders (higher cylinder block) 1004. Reference numeral 1006 denotes a lower bearing end plate (sub bearing) positioned below the second stage cylinder (high stage side cylinder block) 1004, and reference numeral 1007 denotes a crankshaft (drive shaft) connecting the electric motor unit 1002 and the compressor unit. Reference numeral 1008 denotes a first-stage piston (low-stage piston) that moves in a first-stage cylinder (low-stage side cylinder block) 1003, and 1009 denotes a second-stage piston (high-stage piston block that moves in a second-stage cylinder (high stage side cylinder block) 1004 (Stepped piston) 1010 is a flat plate (high-stage discharge cover). Reference numeral 1011 denotes a first-stage suction pipe (low-stage suction pipe), and 1012 denotes a second-stage discharge pipe for directly discharging the second-stage discharge refrigerant to the outside of the sealed container 1. 1013 is a second stage vane (high stage vane), 1014 is a vane spring holding the second stage vane (high stage vane) 1013, 1015 is a second stage vane (high stage vane) 1013, an intermediate plate 1005, a lower bearing. A vane back chamber (high stage back chamber) 1016 hermetically isolated from the refrigerant in the sealed container 1001 by the end plate (sub bearing) 1006 and the second stage cylinder vane groove is a lower bearing end plate (sub bearing) 1006, flat plate ( A second stage discharge valve chamber (high stage discharge chamber) 1017 surrounded by a high stage discharge cover) 1010 includes a vane rear chamber (high stage rear chamber) 1015 and a second stage discharge valve chamber (high stage discharge chamber) 1016. It is an introductory route that communicates.
[0008]
  In such a configuration, a part of the refrigerant gas discharged from the second-stage discharge valve chamber (high-stage discharge chamber) 1016 is guided to the vane back chamber (high-stage back chamber) 1015 through the introduction path 1017, and the vane spring. At the same time, the tip of the second-stage vane (high-stage vane) 1013 is pressed against the second-stage piston (high-stage piston) 1009 with an appropriate force to partition the cylinder space into the suction side and the compression side.
[0009]
[Problems to be solved by the invention]
  However, in such a configuration, the refrigerant gas discharged from the vane back chamber (high stage back chamber) 1015 leaks and flows into the compression chamber through the sliding portion minute gap of the second stage vane (high stage vane) 1013, so that the compression efficiency is improved. There was a problem that the durability of the second-stage vane (high-stage vane) 1013 was difficult to ensure due to insufficient oil supply to the sliding portion minute gap of the second-stage vane (high-stage vane) 1013.
[0010]
  The present invention solves such a conventional problem, and an object of the present invention is to secure supply of lubricating oil to the high-stage vane back chamber.
[0011]
[Means for Solving the Problems]
  In order to solve the above problems, the present invention communicates the oil reservoir on the high-stage (final stage) discharge side and the high-stage (final stage) vane back chamber to the high-stage (final stage) vane back chamber. This ensures a sufficient lubricating oil supply passage.
[0012]
  By securing a sufficient lubricating oil supply passage to the high-stage side (final stage) vane back chamber, the discharge refrigerant gas can be prevented from flowing into the in-cylinder compression space, and the compression efficiency and vane durability can be improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  According to the first aspect of the present invention, a multistage compression mechanism in which a plurality of compression elements are sequentially connected in series in an airtight container and an electric motor connected to a drive shaft of the multistage compression mechanism are housed, and the cylinders of the compression elements are projected and retracted ( While moving forward and backward), the final stage back chamber of the final stage compression element and the final stage discharge side of the final stage compression element communicate with the final stage compression element of each vane that divides into the suction chamber and the compression chamber. Lubricating oil at a pressure equivalent to the discharge of each compression element excluding the final stage compression element is introduced into the back chamber of each vane of the compression element excluding the stage compression element, and a gas equal to or less than the pressure equivalent to the discharge of the previous stage compression element is introduced in the sealed container. In the configuration filled withAt the bottom of the final stage discharge chamber adjacent to the final stage compression element.The oil reservoir communicates with the back chamber of the last stage. According to this configuration, the lubricating oil on which the final stage discharge pressure acts is supplied to the final stage back chamber and supplied to the sliding surface of the vane. Gas leakage can be prevented.Further, the lubricating oil separated from the final stage discharge gas in the final stage discharge chamber can be easily and efficiently flowed down and supplied to the final stage back chamber.
[0014]
  Claim2The final stage discharge chamber is configured such that the final stage discharge chamber surrounds the bearing disposed in the multistage compression mechanism to support the drive shaft and provided with the discharge port of the final stage compression element, and the opening of the final stage back chamber. It is formed. According to this configuration, the lubricating oil separated from the discharge gas discharged from the discharge port is efficiently collected in the oil reservoir at the bottom portion of the outer periphery of the bearing, and sufficient oil can be supplied to the final back chamber that also serves as a part of the oil reservoir.
[0015]
  Claim3According to the invention, the discharge port side of the discharge valve chamber that is recessed in the bearing so as to accommodate the discharge valve device that opens and closes the discharge port is directed toward the opening of the last-stage back chamber. According to this configuration, the lubricating oil discharged together with the discharge gas can be efficiently supplied to the final back chamber.
[0016]
  Claim4The discharge cover fixed to the cylinder of the final stage compression element in such a manner as to surround the bearing and the opening of the rear stage rear chamber so as to form the final stage discharge chamber so as to be isolated from the space inside the sealed container.
Is fixed to a closed container. And according to this structure, formation of the final stage discharge chamber isolated from the space in the sealed container and fixation of the multistage compression mechanism to the sealed container can be realized at the same time.
[0017]
  Claim5In the invention described in (1), the uppermost stream passage of the discharge gas discharge passage from the final stage discharge chamber to the outside of the compressor is disposed so as to project and open toward the upper surface wall of the final stage discharge chamber on the side opposite to the oil reservoir. Is. And according to this structure, lubricating oil most entrainment of the oil sump by the exhaust gas to the exterior of a compressor can be decreased.
[0018]
  Claim6The invention described inA multistage compression mechanism in which a plurality of compression elements are sequentially connected in series and an electric motor connected to the drive shaft of the multistage compression mechanism are housed in an airtight container, and suction is performed while protruding and retracting (advancing / retreating) inside each cylinder of the compression element. The last stage back chamber of the last stage vane of the last stage compression element of each vane partitioned into the chamber and the compression chamber communicates with the last stage discharge side of the last stage compression element, while excluding the last stage compression element Introducing into the back chamber of each vane of the compression element a lubricating oil at a pressure equivalent to the discharge of each compression element excluding the final stage compression element,An oil supply passage is provided in which the inside of the sealed container is filled with a gas corresponding to the suction pressure of the first-stage compression element, and the lubricant in the last-stage back chamber is sequentially introduced into the front-stage back chamber under reduced pressure. According to this configuration, the safety of the compressor as a pressure vessel is ensured, the amount of lubricating oil discharged to the outside of the compressor is reduced, the shortage of lubricating oil in the back chamber of each vane is prevented, and the lubricating oil film is effective. Can be used.
[0019]
  Claim7In the invention described in (1), the first-stage back chamber and the inside of the sealed container are communicated with each other by a throttle passage. And according to this structure, the amount of lubricating oil discharged to the exterior of a compressor can be decreased, the lack of lubricating oil in a compressor can be prevented, and compressor durability can be improved.
[0020]
【Example】
  Embodiments of the present invention will be described below with reference to the drawings.
[0021]
  Example 1
  1 shows a longitudinal section of a rolling piston type rotary two-stage compressor using carbon dioxide refrigerant, FIG. 2 shows a partial longitudinal section of the two-stage compression mechanism in FIG. 1, and FIG. 3 shows a partial detail of FIG. FIG. 4 shows a cross section along the line AA in FIG.
[0022]
  Inside the hermetic container 1, an electric motor 2 and a two-stage compression mechanism 3 are disposed below the electric motor 2. The two-stage compression mechanism 3 includes a high-stage (final stage) compression element 4, a low-stage (first stage) compression element 5, a high-stage (final stage) compression element 4, and a low-stage (first stage) compression element. An intermediate plate 6 disposed between the elements 5, a drive shaft 7 connected to the rotor 2a of the electric motor 2 to drive the high-stage (final stage) compression element 4 and the low-stage (first stage) compression element 5, The main bearing 9 fixed to the high-stage (final stage) side cylinder block 8 of the high-stage (final stage) compression element 4 and the low-stage (first stage) side of the low-stage (first stage) compression element 5 to support the drive shaft 7 The auxiliary bearing 11 is fixed to the cylinder block 10.
[0023]
  A high-stage (final stage) discharge cover 12 that is fixed to the high-stage (final stage) side cylinder block 8 and whose outer periphery is welded to the sealed container 1 surrounds the cylinder block mounting flange portion 9a of the main bearing 9 and A high-stage (final stage) discharge chamber 13 is formed so as to surround the outer peripheral portion of the bearing body 9b. The bottom of the high-stage (final stage) discharge chamber 13 forms an oil reservoir 14, which is in constant communication with a high-stage (final stage) back chamber 16 formed on the side of the high-stage (final stage) vane 15 on the side opposite to the compression chamber. Yes.
[0024]
  The terminal end of the vane spring mounting hole 17 in the high-stage (final stage) back chamber 16 is sealed by a mesa plug 18 press-fitted into the high-stage (final stage) side cylinder block 8. The high-stage (final stage) back chamber 16 and the inside of the sealed container 1 are communicated with each other by an oil return passage 18 a having a throttling function provided in the plug plug 18.
[0025]
  The high-stage (final stage) discharge chamber 13 discharges the discharged refrigerant gas formed through the discharge pipe 19 that is raised and fixed to the cylinder block mounting flange portion 9a of the main bearing 9 and penetrates the side wall of the sealed container 1. The passage 20 leads to the compressor external discharge piping system 21.
[0026]
  A discharge port 22 that opens in the compression chamber of the high-stage (final stage) compression element 4 provided in the main bearing 9 is a discharge valve device 24 that is mounted in a discharge valve chamber 23 that is recessed in the cylinder block mounting flange portion 9a. Is opened and closed by. The discharge port side end of the discharge valve chamber 23 has a high-stage (final stage) rear surface so that the lubricating oil discharged from the discharge port 22 together with the refrigerant gas discharged from the compression chamber can easily flow into the high-stage (final stage) back chamber 16. It is arranged toward the chamber 16.
[0027]
  The low stage (first stage) discharge cover 26 fixed to the low stage (first stage) side cylinder block 10 together with the sub bearing 11 forms a low stage (first stage) discharge chamber 27 together with the sub bearing 11. The low-stage (first stage) discharge chamber 27 sequentially communicates the auxiliary bearing 11, the low-stage (first stage) cylinder block 10, the middle plate 6, the high-stage (final stage) cylinder block 8, and the high-stage (final stage) discharge cover 12. The motor chamber 29 in which the motor 2 is housed is communicated via the intermediate gas passage 28 formed in this manner.
[0028]
  The end of the intermediate gas passage 28 is close to the coil end 2 c of the electric motor 2 by the discharge pipe 29 attached to the high-stage (final stage) discharge cover 12. An intermediate communication pipe 30 that opens in the vicinity of the coil end 2 c at a position opposite to the discharge pipe 29 passes through the side wall of the sealed container 1.
[0029]
  An intermediate passage communication pipe 31 branched and connected from the middle of the intermediate gas passage 28 passes through the side wall of the sealed container 1.
[0030]
  The oil reservoir 32 at the bottom of the hermetic container 1 and the electric motor chamber 29 communicate with each other via an oil dropping hole 33 provided in the high-stage (final stage) discharge cover 12.
[0031]
  The lower (first stage) back chamber 33 of the lower stage (first stage) compression element 5 communicates with the oil reservoir 32 via a vane spring mounting hole 34. The suction-side passage of the low-stage (first stage) compression element 5 communicates with the oil reservoir 32 through a very small hole 35 provided in the auxiliary bearing 11.
[0032]
  The operation of the rolling piston type rotary two-stage compressor using the carbon dioxide refrigerant gas configured as described above will be described.
[0033]
  The refrigerant gas taken into the cylinder of the low-stage (first-stage) compression element 5 through the low-stage (first-stage) suction pipe 36 that penetrates the side wall of the hermetic container 1 is discharged from the oil reservoir 32 through the extremely small holes 35 provided in the auxiliary bearing 11. After the reduced-pressure introduced lubricating oil is compressed in a mixed state, it is discharged into the low-stage (first stage) discharge chamber 27, and is divided and discharged into the motor chamber 29 and the intermediate communication pipe 31.
[0034]
  The refrigerant gas that has flowed into the motor chamber 29 collides with the coil end 2c. At that time, the lubricating oil mixed in the refrigerant gas is separated. Thereafter, the refrigerant gas bypasses the inner and outer surfaces of the coil end 2 c by 180 degrees and is discharged from the intermediate communication pipe 30. The lubricating oil mixed in the refrigerant gas is separated by the flow of the inner and outer surfaces of the coil end 2c of the refrigerant gas, and the electric motor 2 is cooled.
[0035]
  On the other hand, the refrigerant gas discharged from the intermediate communication pipe 31 passes through a heat exchanger (not shown) or air (when the two-stage compressor is used for an air conditioner) or water (the two-stage compressor serves as a water heater). The refrigerant gas discharged from the intermediate communication pipe 30 and merged with the refrigerant gas and then passed through the side wall of the sealed container 1 through the high-stage (final stage) suction pipe 37. It is taken into the cylinder of the stage (final stage) compression element 4. The lubricating oil taken into the cylinder of the high-stage (final stage) compression element 4 together with the refrigerant gas through the intermediate communication pipe 31 is used for sealing the oil film in the minute gap of the compression chamber. 22 is discharged to the high-stage (final stage) discharge chamber 13.
[0036]
  A part of the refrigerant gas discharged from the discharge port 22 flows along the discharge valve chamber 23 toward the high-stage (final stage) back chamber 16 and collides with the inner wall surface of the high-stage (final stage) discharge cover 12. The lubricating oil mixed in the refrigerant gas is separated and flows into the upper (last stage) back chamber 16. The remaining refrigerant gas discharged from the discharge port 22 collides with the entire inner wall surface of the high-stage (final stage) discharge cover 12, and the lubricating oil separated from the refrigerant gas is outside the cylinder block mounting flange portion 9 a of the main bearing 9. After being collected in the surrounding oil reservoir 14, it flows into the upper (last stage) back chamber 16.
[0037]
  Lubricating oil in the high-stage (final stage) back chamber 16 is pumped by the reciprocating motion of the high-stage (final stage) vane 15 to enter and exit the oil reservoir 14, but part of the lubricating oil is in the high stage (final stage). ) The differential pressure flows into the cylinder of the high-stage (final stage) compression element 4 through the gap of the sliding portion of the vane, while the reduced-pressure flow flows into the oil reservoir 32 through the oil return passage 18a provided in the mechler plug 18.
[0038]
  The discharged refrigerant gas discharged from the high-stage (final stage) discharge chamber 13 through the discharge pipe 19 to the outside of the compressor is separated from the lubricating oil through an oil separator (not shown). After the pressure in the oil separator is reduced, the lubricating oil is returned to the oil reservoir 32 through an oil return pipe 38 disposed through the side wall of the sealed container 1.
[0039]
  As described above, according to the above embodiment, the two-stage compression mechanism 3 in which the low-stage (first stage) compression element 5 and the high-stage (final stage) compression element 4 are connected in series in the hermetic container 1 and the two-stage compression mechanism 3. The motor 2 connected to the drive shaft 7 is housed, and a high stage (in each vane that partitions into a suction chamber and a compression chamber while moving forward and backward in each cylinder of each compression element 4, 5 ( The high-stage (final stage) back chamber 16 and the high-stage (final stage) discharge chamber 13 of the high-stage (final stage) vane 15 of the final stage) compression element 4 communicate with the low-stage (first stage) compression element 5. In the configuration in which the lubricating oil in the oil reservoir 32 of the motor chamber 29 where the discharge pressure of the low-stage (first-stage) compression element 5 is introduced into the low-stage (first-stage) back chamber 33 of the low-stage (first-stage) vane, (Final stage) The high-stage (final stage) discharge chamber 13 of the compression element 4 communicates with the high-stage (final stage) back chamber 16 below. Accordingly, the lubricating oil on which the high-stage (final stage) discharge pressure acts is supplied to the high-stage (final stage) back chamber 16 and supplied to the sliding surface of the high-stage (final stage) vane 15, and the oil film in the sliding portion The formation reduces the sliding portion frictional resistance of the high-stage (final stage) vane 15 and seals the sliding part gap, improves the durability of the high-stage (final stage) vane 15, and from the high-stage (final stage) back chamber 16. The compression efficiency can be improved by preventing the discharge gas from leaking into the cylinder.
[0040]
  Further, according to the above embodiment, the oil reservoir 14 at the bottom of the high-stage (final stage) discharge chamber 13 adjacent to the high-stage (final stage) compression element 4 and the high-stage (final stage) back chamber disposed at the lower position thereof. 16, the lubricating oil separated from the high-stage (final stage) discharge gas in the high-stage (final stage) discharge chamber 13 can be efficiently and efficiently supplied to the high-stage (final stage) back chamber 16 through a short path. Thus, the durability and compression efficiency of the high stage vane 15 can be further improved.
[0041]
  Further, according to the above embodiment, the high-stage (final stage) discharge chamber 13 is disposed in the two-stage compression mechanism 3 to support the drive shaft 7 and includes the discharge port 22 of the high-stage (final stage) compression element 4. Since the main bearing 9 and the opening of the high-stage (final stage) back chamber 15 are surrounded, the lubricating oil separated from the discharge gas discharged from the discharge port 22 is attached to the cylinder block of the main bearing 9. The oil is efficiently collected in the oil reservoir 14 at the outer peripheral bottom of the flange portion 9a, and sufficient oil is supplied to the high-stage (final stage) back chamber 16 to further improve the durability and compression efficiency of the high-stage (final stage) vane 15. Improvements can be made.
[0042]
  Further, according to the above embodiment, the low-stage (first stage) vane low-stage (first stage) back chamber of the low-stage (first stage) compression element 5 is decompressed by reducing the lubricant supplied to the high-stage (final stage) back chamber 16. By forming the oil return passage 18a that is supplied to the motor chamber 29 that communicates with the motor chamber 33, the amount of the lubricating oil discharged together with the discharge gas to the high stage (final stage) discharge side is reduced and compressed. In-machine lubrication
Thus, the compressor reliability can be improved and the heat exchange efficiency in the refrigeration cycle piping system can be improved.
[0043]
  Further, according to the above-described embodiment, the discharge port side of the discharge valve chamber 23 recessed in the main bearing 9 to accommodate the discharge valve device 24 for opening and closing the discharge port 22 is the opening of the high-stage (final stage) back chamber 16. By arranging in the direction of the portion, the lubricating oil discharged together with the discharge gas is efficiently supplied to the high stage (final stage) back chamber 16, and the durability and compression efficiency of the high stage (final stage) vane 15 are improved. Further improvement can be achieved.
[0044]
  Further, according to the above embodiment, the main bearing 9 and the high stage (final stage) are formed so as to form the high stage (final stage) discharge chamber 13 so as to be isolated from the space inside the sealed container 1 filled with the low stage (first stage) discharge gas. By fixing the high-stage (final stage) discharge cover 12 fixed to the high-stage (final stage) side cylinder block 8 so as to surround the opening of the back chamber 16 to the closed container 1, The formation of the isolated high-stage (final stage) discharge chamber 13 and the fixing of the two-stage compression mechanism 3 to the hermetic container 1 can be performed at the same time to improve the compressor reliability and reduce the cost.
[0045]
  Further, according to the above-described embodiment, the uppermost stream passage of the discharge gas discharge passage from the high stage (final stage) discharge chamber 13 to the outside of the compressor has the high stage (final stage) discharge chamber 13 on the side opposite to the oil reservoir 14. Due to the projecting opening toward the top wall, the most oil trapped in the oil reservoir due to the exhaust gas to the outside of the compressor is reduced, the compressor reliability is improved by securing the lubricant in the compressor, and the refrigeration cycle piping The heat exchange efficiency in the system can be improved.
[0046]
    (Example 2)
  FIG. 5 shows the communication between the high-stage (final stage) back chamber and the oil reservoir (not shown) of the oil separator (not shown) arranged in the compressor external discharge piping system via the check valve device 51 in the first embodiment. This is the configuration.
[0047]
  That is, a mech plug 18b that closes the end of the high-stage (final stage) back chamber 16b that communicates with the oil reservoir 14 of the high-stage (final stage) discharge chamber 13 is connected to an oil separator (not shown) outside the compressor. An oil return pipe 52 is in communication. The high-stage (final stage) back chamber 16b and the oil reservoir 32 communicate with each other via a throttle passage (not shown) provided in the high-stage (final stage) side cylinder block 8b. Other configurations are the same as those in the first embodiment.
[0048]
  In such a configuration, when the high-stage (final stage) vane 15 is in the forward travel toward the cylinder center side (when the intake gas volume into the cylinder is in the expansion stroke), the high-stage (final stage) back chamber 16b is This is the state of the suction stroke in the pump action caused by the reciprocating motion of the high stage (final stage) vane 15. At this timing, lubricating oil is introduced from the oil separator (not shown) outside the compressor into the high stage (final stage) back chamber 16b.
[0049]
  When the high-stage (final stage) vane 15 is in the reverse stroke in which it is separated from the cylinder center side (when the compression stroke is progressing in the cylinder), the high-stage (final stage) back chamber 16b is the high-stage (final stage) vane. It is the state of the discharge stroke in the pump action resulting from 15 reciprocating motions. At this timing, the high-stage (final stage) back chamber 16b is blocked from communicating with an oil separator (not shown) outside the compressor by the check action of the check valve device 51.
[0050]
  After the compressor operation is stopped, the lubricating oil is returned to the high stage back chamber 16b by its own weight from an oil separator (not shown) outside the compressor.
[0051]
  According to the above embodiment, in the configuration in which the sealed container 1b is filled with the discharge pressure gas of the low-stage (first stage) compression element 5, the oil separator (on the discharge side of the high-stage (final stage) compression element 4 ( By connecting the oil reservoir (not shown) and the high-stage (final stage) back chamber 16b through the check valve device 51 via the oil return pipe 52, the lubricating oil discharged to the outside of the compressor is fed to the high-stage (final stage). ) The sliding part of vane 15
Effectively used for sliding, it is possible to improve the durability of the high stage (final stage) vane 15 and to improve the compression efficiency by preventing leakage of discharged gas from the high stage (final stage) back chamber 16b into the cylinder.
[0052]
  (Example 3)
  FIG. 6 shows a configuration in which the sealed container in Example 1 is filled with the suction gas pressure.
[0053]
  That is, the suction pipe 61 passes through the side wall of the sealed container 1c and communicates with the motor chamber 29c. A low-stage (first stage) suction pipe 36c disposed close to the coil end 2c of the electric motor 2 communicates with the suction side of the low-stage (first stage) compression element 5c.
[0054]
  The end of the high-stage (final stage) back chamber 16c of the high-stage (final stage) compression element 4c is closed by a mechlet plug 18c. The low-stage (first-stage) back chamber 33c of the low-stage (first-stage) compression element 5c is connected to the motor chamber 29c via a throttle passage 63 provided in a mech plug 64 disposed at the end of the low-stage (first-stage) back chamber 33c. It communicates with the oil reservoir 32c at the bottom. The high stage (final stage) back chamber 16c and the low stage (first stage) back chamber 33c communicate with each other via a throttle passage 62 provided in the intermediate plate 6c. Other configurations are the same as those in the first embodiment.
[0055]
  In such a configuration, the refrigerant gas flowing into the electric motor chamber 29c from the suction side of the refrigeration cycle through the suction pipe 61 collides with the coil end 2c. At this time, the lubricating oil mixed in the refrigerant gas is separated and collected in the oil reservoir 32c. Thereafter, the refrigerant gas is taken into the cylinder of the low-stage (first-stage) compression element 5c through the low-stage (first-stage) suction pipe 36c and compressed.
[0056]
  When the oil surface height of the oil reservoir 32c increases, excess lubricating oil is sucked from the low-stage (first stage) suction pipe together with the suction refrigerant gas, and is used for oil film sealing and sliding portion lubrication of the compression chamber minute gap.
[0057]
  The lubricating oil separated from the refrigerant gas discharged in the high-stage (final stage) discharge chamber flows into the high-stage (final stage) back chamber 16c, and is then depressurized via the throttle passage 62 provided in the intermediate plate 6c. (First stage) Supplyed to the back chamber 33c. The lubricating oil in the low-stage (first stage) back chamber 33c is further depressurized via the throttle passage 63 and returned to the oil reservoir 32c.
[0058]
  According to the above-described embodiment, the two-stage compression mechanism 3c in which the low-stage (first stage) compression element 5c and the high-stage (final stage) compression element 4c are connected in series in the sealed container 1c, and the electric motor 2 connected to the drive shaft 7. The high stage (final stage) of each vane that divides into the suction chamber and the compression chamber while appearing (advancing and retreating) in each cylinder of each compression element 4c, 5c ( While the last stage) upper stage (final stage) back chamber 16c of the vane 15 and the high stage (final stage) discharge chamber 13 communicate with each other, the lower stage (first stage) back chamber 33c of the lower stage (first stage) compression element 5c While supplying the low-stage discharge pressure to the low-stage discharge pressure of the high-stage (final-stage) back chamber 16c, the lubricating oil at the discharge equivalent pressure of each compression element excluding the final-stage compression element is introduced, and the inside of the sealed container 1c is low. By filling with the suction pressure gas of the stage (first stage) compression element 5c, the sealed capacity It is possible to ensure the reliability of the withstand voltage-hermetic compressor as a pressure vessel to lower the pressure resistance of 1c.
[0059]
  Further, according to the above embodiment, the lubricating oil separated from the refrigerant gas discharged from the high-stage (final stage) discharge chamber 13 passes through the high-stage (final stage) back chamber 16c, and the low-stage (first-stage) compression element 5c is low. After supplying to the stage (first stage) back chamber 33c, the amount of lubricating oil discharged to the outside of the compressor is reduced by returning oil into the sealed container 1c filled with the suction pressure gas of the low stage (first stage) compression element 5c. In addition, lack of lubricating oil in the compressor can be prevented, sliding portion durability can be improved by effectively using the lubricating oil film, and compression efficiency can be improved by sealing the compression chamber gap.
[0060]
  In the above-described embodiment, the two-stage compressor has been described. However, the compression elements can be connected to each other in series and in series to develop a multistage compression mechanism such as a three-stage compression or a four-stage compression.
[0061]
  In Example 2, the oil reservoir of the oil separator placed in the compressor external discharge piping system is connected to the high-stage (final stage) back chamber, but sufficient oil supply to the high-stage (final stage) back chamber is ensured. If possible, the low-stage (first-stage) back chamber may be communicated via a throttle passage, and a check valve device can be dispensed with.
[0062]
  In the above embodiment, a rolling piston type rotary two-stage compressor using carbon dioxide refrigerant has been described. However, a two-stage rolling piston type rotary that compresses other gases (for example, oxygen, nitrogen, helium, air, etc.). In the case of the type compressor, the same action and effect are produced.
[0063]
  Moreover, although the said Example demonstrated individually about Example 1-Example 3, by combining the structure of Example 1-Example 3 suitably according to the operating conditions, compression load conditions, etc. of a two-stage compressor, it is further. It is possible to realize a two-stage compressor excellent in high efficiency and durability.
[0064]
  Further, in the above embodiment, the vertical type compressor has been described. However, the horizontal type rolling piston type rotary two-stage compressor having the configuration in which the back chamber of the vane is arranged at the bottom of the compressor is similar to the above. The effect can be expected. In this horizontal arrangement, the high-stage discharge chamber can be arranged on either the main bearing arranged on the electric motor side or the auxiliary bearing side separated from the electric motor.
[0065]
【The invention's effect】
  As apparent from the above embodiment, the invention according to claim 1 houses a multistage compression mechanism in which a plurality of compression elements are sequentially connected in series in a sealed container and an electric motor connected to the drive shaft of the multistage compression mechanism, The last stage back chamber of the last stage vane of the last stage compression element and the last stage of the last stage compression element of each vane partitioning into the suction chamber and the compression chamber while appearing and retracting (advancing / retreating) in each cylinder of the compression element While communicating with the discharge side, while introducing the lubricating oil corresponding to the discharge pressure of each compression element excluding the final stage compression element into the back chamber of each vane of the compression element excluding the final stage compression element, In the configuration filled with gas below the discharge equivalent pressure of the compression element,At the bottom of the final stage discharge chamber adjacent to the final stage compression element.The oil reservoir communicates with the final-stage back chamber provided below the oil reservoir. According to this configuration, the lubricating oil acting on the final-stage discharge pressure is supplied to the final-stage back chamber to slide the vane. To reduce the frictional resistance of the sliding part of the last stage vane and seal the sliding part gap, improve the durability of the last stage vane, and discharge gas from the back chamber of the last stage into the cylinder. The compression efficiency can be improved by preventing leakage.Further, the lubricating oil separated from the final stage discharge gas in the final stage discharge chamber can be easily and efficiently flowed down and supplied to the final stage back chamber.
[0066]
  Claim2The final stage discharge chamber is configured such that the final stage discharge chamber surrounds the bearing disposed in the multistage compression mechanism to support the drive shaft and provided with the discharge port of the final stage compression element, and the opening of the final stage back chamber. According to this configuration, the lubricating oil separated from the discharge gas discharged from the discharge port is efficiently collected in the oil reservoir at the bottom of the outer periphery of the bearing, and is sent to the final stage back chamber that forms part of the oil reservoir. Therefore, the durability and compression efficiency of the final stage vane can be further improved.
[0067]
  Claim3In the invention described in the above, the discharge port side of the discharge valve chamber that is recessed in the bearing so as to accommodate the discharge valve device that opens and closes the discharge port is directed toward the opening of the last-stage back chamber. According to this, since the lubricating oil discharged together with the discharged gas can be efficiently supplied to the final back chamber, the durability of the final stage vane and the compression efficiency can be further improved.
[0068]
  Claim4In the invention described in the above, the discharge cover fixed to the cylinder of the final stage compression element is hermetically sealed so as to surround the bearing and the opening of the rear stage rear chamber so as to form the final stage discharge chamber so as to be isolated from the space inside the sealed container. It is fixed to the container, and according to this configuration, the final stage is isolated from the space inside the sealed container.
Since the formation of the discharge chamber and the fixing of the multistage compression mechanism to the sealed container can be realized at the same time, the compressor reliability can be improved and the cost can be reduced.
[0069]
  Claim5In the invention described in (1), the uppermost stream passage of the discharge gas discharge passage from the final stage discharge chamber to the outside of the compressor is disposed so as to project and open toward the upper surface wall of the final stage discharge chamber on the side opposite to the oil reservoir. Therefore, according to this configuration, it is possible to reduce the most entrained lubricating oil in the oil reservoir due to the gas discharged to the outside of the compressor, so that the reliability of the compressor can be improved by securing the lubricating oil in the compressor, and in the refrigeration cycle piping system Heat exchange efficiency can be improved.
[0070]
  Claim6The invention described inA multistage compression mechanism in which a plurality of compression elements are sequentially connected in series and an electric motor connected to the drive shaft of the multistage compression mechanism are housed in an airtight container, and suction is performed while protruding and retracting (advancing / retreating) inside each cylinder of the compression element. The last stage back chamber of the last stage vane of the last stage compression element of each vane partitioned into the chamber and the compression chamber communicates with the last stage discharge side of the last stage compression element, while excluding the last stage compression element Introducing into the back chamber of each vane of the compression element a lubricating oil at a pressure equivalent to the discharge of each compression element excluding the final stage compression element,The airtight container is filled with a gas equivalent to the suction pressure of the first stage compression element, and the oil supply passage is provided to allow the lubricant in the final stage back chamber to flow into the front back chamber in a reduced pressure sequence. The pressure resistance of the compressor can be lowered to ensure the safety of the compressor as a pressure vessel, and the weight and cost can be reduced by reducing the thickness of the sealed vessel. In addition, the amount of lubricating oil discharged to the outside of the compressor can be reduced, the shortage of lubricating oil in the back chamber of each vane can be prevented, and the lubricating oil film can be effectively utilized.
[0071]
  Claim7The invention described in 1 is a communication between the first-stage back chamber and the inside of the sealed container through a throttle passage. According to this configuration, the amount of lubricating oil discharged to the outside of the compressor can be reduced. The oil shortage can be prevented, and the sliding portion durability can be improved by effectively using the lubricating oil film, and the compression efficiency can be improved by sealing the compression chamber gap.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a rolling piston type rotary two-stage compressor showing an embodiment of the present invention.
FIG. 2 is a partial sectional view of a compression mechanism section in the compressor.
FIG. 3 is a partial detail view of the compression mechanism.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is a partial longitudinal sectional view of a rolling piston type rotary two-stage compressor according to another embodiment.
FIG. 6 is a partial longitudinal sectional view of a rolling piston type rotary two-stage compressor in still another embodiment.
FIG. 7 is a longitudinal sectional view of a conventional rolling piston type rotary two-stage compressor.
FIG. 8 is a cross-sectional view taken along line BB of the compressor.
[Explanation of symbols]
  1 Airtight container
  1c Airtight container
  2 Electric motor
  3 Two-stage compression mechanism
  3c Two-stage compression mechanism
  4 High stage (final stage) compression element
  4c Higher stage (last stage) compression element
  5 Low stage (first stage) compression element
  5c Low stage (first stage) compression element
  7 Drive shaft
  8 Higher (last) cylinder block
  9 Main bearing
  12 High (last) discharge cover
  13 High (final) discharge chamber
  14 Oil sump
  15 High (final) vanes
  16 High (last stage) back room
  16b High stage (last stage) back room
  16c High stage (last stage) back room
  18a Oil return passage
  22 Discharge port
  23 Discharge valve chamber
  24 Discharge valve device
  29 Electric motor room
  32 Oil sump
  33 Lower (first stage) back room
  33c Lower stage (first stage) rear room
  51 Check valve device
  52 Oil return pipe

Claims

A multistage compression mechanism in which a plurality of compression elements are sequentially connected in series in a sealed container and an electric motor connected to a drive shaft of the multistage compression mechanism are housed, and suction is performed while protruding and retracting (advancing / retreating) inside each cylinder of the compression element. The last stage back chamber of the last stage vane of the last stage compression element of each vane partitioned into the chamber and the compression chamber communicates with the last stage discharge side of the last stage compression element, while excluding the last stage compression element Lubricating oil at a pressure equivalent to the discharge of each compression element excluding the final stage compression element is introduced into the back chamber of each vane of the compression element, and a gas having a pressure equal to or less than the discharge equivalent pressure of the previous stage compression element is introduced into the sealed container. The rotary multistage compressor in which the oil reservoir at the bottom of the final stage discharge chamber adjacent to the final stage compression element and the final stage back chamber are communicated with each other.

Last stage discharge chamber, a bearing provided with a multi-stage disposed compression mechanism and the discharge port of the last stage compression element so as to support the drive shaft, the final stage back surface chamber according to claim 1 which is formed in a manner to surround the opening of the The rotary multistage compressor described.

The rotary multistage compressor according to claim 2, wherein the discharge port side of the discharge valve chamber recessed in the bearing to accommodate the discharge valve device that opens and closes the discharge port is directed toward the opening of the rear chamber of the final stage.

Claim that the discharge cover fixed to the cylinder of the final stage compression element is fixed to the sealed container so as to surround the bearing and the opening of the rear chamber of the final stage so as to form the final stage discharge chamber isolated from the space inside the sealed container Item 3. The rotary multistage compressor according to Item 2 .

The rotary according to claim 2 , wherein the uppermost flow path of the discharge gas discharge path from the final stage discharge chamber to the outside of the compressor is disposed so as to project and open toward the upper surface wall of the final stage discharge chamber opposite to the oil reservoir. Type multistage compressor.

A multistage compression mechanism in which a plurality of compression elements are sequentially connected in series in a sealed container and an electric motor connected to a drive shaft of the multistage compression mechanism are housed, and suction is performed while protruding and retracting (advancing / retreating) inside each cylinder of the compression element. The last stage back chamber of the last stage vane of the last stage compression element of each vane partitioned into the chamber and the compression chamber communicates with the last stage discharge side of the last stage compression element, while excluding the last stage compression element Lubricating oil at a pressure equivalent to the discharge of each compression element except the final stage compression element is introduced into the back chamber of each vane of the compression element, and the inside of the sealed container is filled with a gas at a pressure equivalent to the suction of the first stage compression element. A rotary multi-stage compressor provided with an oil supply passage through which the lubricant in the final stage rear chamber flows into the front rear chamber under reduced pressure.

The rotary multistage compressor according to claim 6, wherein the first-stage back chamber and the inside of the sealed container are communicated with each other by a throttle passage.