JP2004092404A

JP2004092404A - Multistage compression rotary compressor

Info

Publication number: JP2004092404A
Application number: JP2002250927A
Authority: JP
Inventors: Kenzo Matsumoto; 松本　兼三; Kazuaki Fujiwara; 藤原　一昭; Haruhisa Yamazaki; 山崎　晴久; Yoshio Watabe; 渡部　由夫; Kentaro Yamaguchi; 山口　賢太郎; Noriyuki Tsuda; 津田　徳行; Masaji Yamanaka; 山中　正司; Kazuya Sato; 里　和哉
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 2002-08-29
Filing date: 2002-08-29
Publication date: 2004-03-25
Anticipated expiration: 2022-08-29
Also published as: JP3857967B2

Abstract

<P>PROBLEM TO BE SOLVED: To avoid an unstable operation behavior such as vane skip in the use of a combustible coolant in an internal intermediate pressure type multistage compression rotary compressor. <P>SOLUTION: The coolant compressed by a first rotary compression element 32 is discharged into a sealed casing 12, and the discharged coolant of intermediate pressure is compressed by a second rotary compression element 34. The discharge silencing chamber 62 of the second rotary compression element 34 is allowed to communicate with a second back pressure chamber 80 through a communicating passage 90, and the second back pressure chamber 80 is allowed to communicate with a first back pressure chamber 82 through a communicating hole 110 formed in an intermediate partition plate 36. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、密閉容器内に電動要素と、この電動要素の回転軸にて駆動される第１及び第２の回転圧縮要素を備え、第１の回転圧縮要素で圧縮された冷媒を第２の回転圧縮要素で圧縮する多段圧縮式ロータリコンプレッサに関するものである。
【０００２】
【従来の技術】
従来この種ロータリコンプレッサは、回転圧縮要素の吸入ポートから冷媒ガスがシリンダの低圧室側に吸入され、ローラとベーンの動作により圧縮されてシリンダの高圧室側の吐出ポートより一旦密閉容器内に吐出され、この密閉容器から外部に吐出される構成とされている。また、前記ベーンはシリンダの半径方向に設けられた溝内に移動自在に取り付けられている。係るベーンはローラに押し付けられてシリンダ内を低圧室側と高圧室側に区画するものである。ベーンの後側には当該ベーンをローラ側に付勢するスプリングが設けられると共に、溝にはベーンをローラ側に付勢するための密閉容器内と連通する背圧室が設けられている。そして、背圧室には密閉容器内の高圧が加えられて、ベーンをローラ側に付勢している。
【０００３】
一方、近年ではフロン冷媒によるオゾン層破壊の問題から、この種ロータリコンプレッサにおいてもフロン以外のＨＣ冷媒、例えばプロパン（Ｒ２９０）などの可燃性の冷媒の使用が検討されている。
【０００４】
ところで、プロパンなどの可燃性冷媒は、安全性等の問題から封入量を極力少なくする必要がある。通常プロパンを冷媒として使用する場合の安全上の限界量は１５０ｇ程であり、実際には余裕を見て１００ｇ（冷蔵庫用では５０ｇ）程に抑える必要がある。
【０００５】
一方、ロータリコンプレッサでは密閉容器内に圧縮後の冷媒が吐出されるため、同容量のレシプロタイプのコンプレッサに比較して、封入しなければならない冷媒量は３０ｇ〜５０ｇ程増加してしまう。そのため、可燃性冷媒を用いたロータリコンプレッサの実用化は非常に厳しいものとなっていた。
【０００６】
【発明が解決しようとする課題】
そこで、密閉容器内が中間圧となる多段圧縮式ロータリコンプレッサに可燃性冷媒を用いることが検討されている。この場合、密閉容器に高圧の冷媒を吐出する場合と比べて、密閉容器内の圧力が低くなる。即ち、圧力が低いほど冷媒の密度が低くなるため、密閉容器内に存在する冷媒量が少なくなり、密閉容器内に封入する冷媒量を減らすことができる。特に、第１の回転圧縮要素の排除容積に対して第２の回転圧縮要素の排除容積の比を大きくした場合には中間圧が上がりにくくなるので、密閉容器内に封入する冷媒量をより一層減らすことができるようになる。
【０００７】
しかしながら、ロータリコンプレッサの密閉容器内を中間圧として、上述する如く中間圧を低く抑えた場合には、コンプレッサ始動時に第１の回転圧縮要素のベーンに背圧として加わる密閉容器内の圧力が上がりにくいため、ベーン飛びが生じる恐れがあった。
【０００８】
また、内部中間圧型の場合、ロータリコンプレッサ停止後にコンプレッサ内が平衡圧に達するのに時間がかかるため、再起動時に始動性が悪化してしまうという問題も生じていた。
【０００９】
本発明は、係る従来技術の課題を解決するために成されたものであり、内部中間圧型多段圧縮式ロータリコンプレッサに可燃性冷媒を用いた場合における、ベーン飛び等の不安定な運転挙動を回避し、又、コンプレッサの始動性を改善することを目的とする。
【００１０】
【課題を解決するための手段】
即ち、本発明の多段圧縮式ロータリコンプレッサでは、第１及び第２の回転圧縮要素を構成する第１及び第２のシリンダと、電動要素の回転軸に形成された偏心部により各シリンダ内でそれぞれ偏心回転する第１及び第２のローラと、各ローラに当接して各シリンダ内を低圧室側と高圧室側にそれぞれ区画する第１及び第２のベーンと、各ベーンを常時各ローラ側に付勢するための第１及び第２の背圧室とを備え、冷媒として可燃性冷媒を用い、第１の回転圧縮要素で圧縮された冷媒を密閉容器内に吐出し、この吐出された中間圧の冷媒を第２の回転圧縮要素で圧縮すると共に、第２の回転圧縮要素の冷媒吐出側と第１及び第２の背圧室とを連通させたので、第１及び第２の背圧室に第２の回転圧縮要素で圧縮された高圧の冷媒が加えられる。
【００１１】
請求項２の発明では上記発明に加えて、第２のシリンダの開口面を閉塞する支持部材と、この支持部材内に構成され、第２のシリンダ内で圧縮された冷媒が吐出される吐出消音室と、支持部材内に形成され、吐出消音室と第２の背圧室とを連通する連通路と、第１及び第２のシリンダ間に狭持された中間仕切板と、この中間仕切板内に形成され、第２の背圧室と第１の背圧室とを連通する連通孔とを備えたので、比較的簡単な構造で第２の回転圧縮要素の冷媒吐出側の高圧を第１及び第２の背圧室に加えられるようになる。
【００１２】
請求項３の発明では請求項２の発明に加えて、吐出消音室と密閉容器内とを連通する均圧用通路と、この均圧用通路を開閉する均圧弁とを備え、この均圧弁は、吐出消音室内の圧力が密閉容器内の圧力より低くなった場合に均圧用通路を開放するので、第１の回転圧縮要素と第２の回転圧縮要素及び密閉容器内の均圧を早めることができるようになる。
【００１３】
請求項４の発明では、冷媒として可燃性冷媒を用い、第１の回転圧縮要素で圧縮された冷媒を密閉容器内に吐出し、この吐出された中間圧の冷媒を第２の回転圧縮要素で圧縮すると共に、第２の回転圧縮要素の冷媒吐出側の圧力が密閉容器内の圧力より低くなった場合に、当該第２の回転圧縮要素の冷媒吐出側と密閉容器内とを連通させる均圧弁を備えるので、コンプレッサ停止後に、密閉容器内の均圧を早めることができるようになる。
【００１４】
請求項５の発明では請求項４の発明に加えて、第２の回転圧縮要素を構成するシリンダと、このシリンダの開口面を閉塞する支持部材と、この支持部材内に構成され、シリンダ内で圧縮された冷媒が吐出される吐出消音室と、この吐出消音室と密閉容器内とを区画するカバーと、このカバー内に形成された均圧用通路とを備え、均圧弁は、吐出消音室内に設けられて均圧用通路を開閉するので、構造を簡素化し、且つ、スペース効率を向上させることができるようになる。
【００１５】
【発明の実施の形態】
次に、図面に基づき本発明の実施の形態を詳述する。図１は本発明の多段圧縮式ロータリコンプレッサの実施例として、第１及び第２の回転圧縮要素３２、３４を備えた内部中間圧型多段（２段）圧縮式ロータリコンプレッサ１０の縦断面図を示している。
【００１６】
図１において、実施例のロータリコンプレッサ１０はプロパン（Ｒ２９０）を冷媒として使用する内部中間圧型多段圧縮式ロータリコンプレッサで、この多段圧縮式ロータリコンプレッサ１０は、鋼板からなる円筒状の密閉容器１２Ａ、及びこの密閉容器１２Ａの上部開口を閉塞する略椀状のエンドキャップ（蓋体）１２Ｂとで形成されるケースとしての密閉容器１２と、この密閉容器１２の容器本体１２Ａの内部空間の上側に配置収納された電動要素１４と、この電動要素１４の下側に配置され、電動要素１４の回転軸１６により駆動される第１の回転圧縮要素３２及び第２の回転圧縮要素３４からなる回転圧縮機構部１８とにより構成されている。
【００１７】
尚、密閉容器１２は底部をオイル溜めとする。また、前記容器本体１２Ａの側面には電動要素１４に電力を供給するためのターミナル（配線を省略）２０が取り付けられている。
【００１８】
電動要素１４は、密閉容器１２の上部空間の内面に沿って環状に取り付けられたステータ２２と、このステータ２２の内側に若干の隙間を設けて挿入設置されたロータ２４とからなる。そして、このロータ２４には鉛直方向に延びる回転軸１６が固定されている。
【００１９】
ステータ２２は、ドーナッツ状の電磁鋼板を積層した積層体２６と、分布巻き方式により巻装されたステータコイル２８を有している。また、ロータ２４もステータ２２と同様に電磁鋼板の積層体３０で形成されている。
【００２０】
前記第１の回転圧縮要素３２と第２の回転圧縮要素３４との間には中間仕切板３６が狭持されている。即ち、第１の回転圧縮要素３２と第２の回転圧縮要素３４は、中間仕切板３６と、この中間仕切板３６の上下に配置された上シリンダ（第２のシリンダ）３８、下シリンダ（第１のシリンダ）４０と、上下シリンダ３８、４０内を１８０度の位相差を有して回転するように回転軸１６に設けられた偏心部４２、４４に嵌合されて偏心回転する上ローラ（第２のローラ）４６、下ローラ（第１のローラ）４８と、この上下ローラ４６、４８に当接して上下シリンダ３８、４０内をそれぞれ低圧室側と高圧室側に区画するベーン（第２のベーン）５０、ベーン（第１のべーン）５２と、上シリンダ３８の上側の開口面及び下シリンダ４０の下側の開口面を閉塞して回転軸１６の軸受けを兼用する支持部材としての上部支持部材５４及び下部支持部材５６にて構成される。
【００２１】
上記第１及び第２の回転圧縮要素３２、３４を構成する上下シリンダ３８、４０内には、図２で示すようにベーン５０、５２を収納する案内溝７０、７２が形成されており、この案内溝７０、７２の外側、即ち、ベーン５０、５２の背面側には、バネ部材としてのスプリング７４、７６を収納する収納部７０Ａ、７２Ａが形成されている。このスプリング７４、７６はベーン５０、５２の背面側端部に当接し、常時ベーン５０、５２をローラ４６、４８側に付勢する。そして、この収納部７０Ａ、７２Ａは案内溝７０、７２側と密閉容器１２（容器本体１２Ａ）側に開口しており、収納部７０Ａ、７２Ａに収納されたスプリング７４、７６の密閉容器１２側には図示しないプラグが設けられ、スプリング７４、７６の抜け止めの役目を果たす。また、プラグの周面には各プラグと収納部７０Ａ、７２Ａの内面間をシールするために図示しないＯリングが取り付けられている。
【００２２】
また、案内溝７０と収納部７０Ａの間には、スプリング７４と共にベーン５０を常時ローラ４６側に付勢するため、第２の回転圧縮要素３４の冷媒吐出圧をベーン５０に加える第２の背圧室８０が設けられている。この第２の背圧室８０の上面は後述する連通路９０に連通する。また、第２の背圧室８０の下面は中間仕切板３６に形成された連通孔１１０にて後述する第１の背圧室８２と連通している。
【００２３】
このように、吐出消音室６２と第２の背圧室８０とを連通路９０にて連通させることにより、第２の回転圧縮要素３４で圧縮され、吐出消音室６２内に吐出された高圧の冷媒が連通路９０から第２の背圧室８０に加えられる。これにより、ベーン５０がローラ４６側に充分に付勢されるので、ベーン飛び等の第２の回転圧縮要素３４の不安定な運転挙動を回避することができるようになる。
【００２４】
前記下シリンダ４０のベーン５２を収納する案内溝７２と収納部７２Ａの間には、スプリング７６と共にベーン５２を常時ローラ４８側に付勢するための前述する第１の背圧室８２が設けられている。この第１の背圧室８２の上面は前述する連通孔１１０にて前記第２の背圧室８０と連通している。
【００２５】
このように、第２の背圧室８０と第１の背圧室８２とを連通孔１１０にて連通させることにより、前記連通路９０を経て第２の背圧室８０に加えられる吐出消音室６２内の高圧を第１の背圧室８２内に導入することができるようになる。これにより、ベーン５２がローラ４８側に充分に付勢されるようになるので、始動時に第１の背圧室８２内の圧力上昇が迅速となり、ベーン飛びなどの第１の回転圧縮要素３２の不安定な運転挙動を回避することができるようになる。
【００２６】
特に、本発明では密閉容器１２内を中間圧とすると共に、後述する如く密閉容器１２内の中間圧が低くなるように第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積の比を大きく設定しているので、ロータリコンプレッサ１０の起動時に、密閉容器１２内の圧力が上がりにくいために、ベーン５２に充分な背圧がかからなくなるという不都合を回避することができるようになる。これにより、ロータリコンプレッサ１０の信頼性の向上を図ることができるようになる。
【００２７】
また、上部支持部材５４に連通路９０を形成して、中間仕切板３６に連通孔１１０を形成するだけで、特別な機構を用いずに各ベーン５０、５２に充分な背圧をかけることができるようになるので、加工コストを低減しながら信頼性の高いロータリコンプレッサ１０を生産できるようになる。
【００２８】
そして、上下シリンダ３８、４０には、図示しない吸込ポートにて上下シリンダ３８、４０の内部とそれぞれ連通する吸込通路５８、６０が設けられている。また、上部支持部材５４には、上シリンダ３８内で圧縮された冷媒を吐出ポート３９から上部支持部材５４の凹陥部を壁としてのカバーによって閉塞することにより形成された吐出消音室６２が設けられている。即ち、吐出消音室６２は当該吐出消音室６２を画成する壁としての上部カバー６６にて閉塞される。
【００２９】
上部支持部材５４内には前述する連通路９０が形成されている。この連通路９０は、第２の回転圧縮要素３４の上シリンダ３８の吐出ポート３９に連通する吐出消音室６２と前記第２の背圧室８０とを連通する通路である。
【００３０】
また、前記上部カバー６６には、図３に示すように密閉容器１２内と吐出消音室６２内とを連通する均圧用通路１００が形成されている。この均圧用通路１００は上部カバー６６を上下に貫通する孔であり、均圧用通路１００の下面は吐出消音室６２内に取り付けられた均圧弁１０１にて開閉可能に閉塞されている。
【００３１】
この均圧弁１０１は縦長略矩形状の金属板からなる弾性部材にて構成されており、この均圧弁１０１の下側には均圧弁抑え板としてのバッカーバルブ１０２が配置され、上部カバー６６の下面に取り付けられている。そして、均圧弁１０１の一側が均圧用通路１００に当接して密閉すると共に、他側は均圧用通路１００と所定の間隔を存して設けられた上部カバー６６の取付孔１０３にカシメピン１０４により固着されている。
【００３２】
そして、ロータリコンプレッサ１０停止後に、吐出消音室６２の圧力が密閉容器１２内の圧力より低くなると、密閉容器１２内の圧力が図３の上方から均圧用通路１００を閉じている均圧弁１０１を押して均圧用通路１００を開き、吐出消音室６２へ吐出させる。このとき、均圧弁１０１は他側を上部カバー６６に固着されているので均圧用通路１００に当接している一側が反り下がり、均圧弁の開き量を規制しているバッカーバルブ１０２に当接する。そして、吐出消音室６２内の圧力が密閉容器１２内の圧力と同じ圧力、若しくは、それより高くなると、均圧弁１０１がバッカーバルブ１０２から離れ、均圧用通路１００を閉塞する。
【００３３】
このように、吐出消音室６２の圧力が密閉容器１２内の圧力より低くなると、均圧用通路１００を開き、吐出消音室６２へ吐出させるようにしたので、ロータリコンプレッサ１０停止後に密閉容器１２内の中間圧が下がりにくいという不都合を回避することができるようになる。これにより、吐出消音室６２内と密閉容器１２内の均圧を早めることができるようになる。
【００３４】
更に、均圧弁１０１を吐出消音室６２内に設けたので、上方の電動要素１４を上部カバー６６に接近させても干渉しなくなる。従って、スペース効率が向上し、ロータリコンプレッサ１０の小型化を図ることができるようになる。また、均圧弁１０１を上部カバー６６下面に取り付けているので、取付作業も容易に行うことができる。
【００３５】
また、吐出消音室６２の下面には、吐出ポート３９を開閉可能に閉塞する吐出弁１２７が設けられている（図１、図２では図示せず）。この吐出弁１２７は縦長略矩形状の金属板からなる弾性部材にて構成されており、この吐出弁１２７の上側には吐出弁抑え板としてのバッカーバルブ１２８が配置され、上部支持部材５４に取り付けられている。そして、吐出弁１２７の一側が吐出ポート３９に当接して密閉すると共に、他側は吐出ポート３９と所定の間隔を存して設けられた上部支持部材５４の取付孔１２９にカシメピン１３０により固着されている。
【００３６】
そして、上シリンダ３８内で圧縮され、所定の圧力に達した冷媒ガスが、図の下方から吐出ポート３９を閉じている吐出弁１２７を押し上げて吐出ポート３９を開き、吐出消音室６２へ吐出させる。このとき、吐出弁１２７は他側を上部支持部材５４に固着されているので吐出ポート３９に当接している一側が反り上がり、吐出弁１２７の開き量を規制している図示しないバッカーバルブに当接する。冷媒ガスの吐出が終了する時期になると、吐出弁１２７がバッカーバルブから離れ、吐出ポート３９を閉塞する。
【００３７】
一方、下シリンダ４０内で圧縮された冷媒ガスは図示しない吐出ポートから下部支持部材５６の電動要素１４とは反対側（密閉容器１２の底部側）に形成された吐出消音室６４に吐出される。この吐出消音室６４は、中心に回転軸１６及び前述した回転軸１６の軸受けを兼用する下部支持部材５６が貫通するための孔を有すると共に、下部支持部材５６の電動要素１４とは反対側を覆うカップ６５にて構成されている。
【００３８】
この場合、上部支持部材５４の中央には軸受け５４Ａが起立形成されている。又、下部支持部材５６の中央には軸受け５６Ａが貫通形成されており、回転軸１６は上部支持部材５４の軸受け５４Ａと下部支持部材５６の軸受け５６Ａにて保持されいる。
【００３９】
そして、第１の回転圧縮要素３２の吐出消音室６４と密閉容器１２内とは連通路にて連通されており、この連通路は下部支持部材５６、上部支持部材５４、上部カバー６６、上下シリンダ３８、４０、中間仕切板３６を貫通する図示しない孔である。この場合、連通路の上端には中間吐出管１２１が立設されており、この中間吐出管１２１から密閉容器１２内に中間圧の冷媒が吐出される。
【００４０】
このように、第１の回転圧縮要素３２で圧縮された中間圧の冷媒ガスを密閉容器１２内に吐出するので、密閉容器１２に高圧の冷媒を吐出する場合と比べて、密閉容器１２内に吐出される冷媒量が少なくなる。即ち、圧力が低いほど冷媒の密度が低くなるため、中間圧の冷媒を密閉容器１２内に吐出した方が、高圧の冷媒を密閉容器１２内に吐出するより、冷媒のガス密度が低くなり、密閉容器１２内に存在する冷媒量が少なくなる。
【００４１】
この様子を図４及び図５を参照して説明する。図４は冷媒の蒸発温度に対する本発明の内部中間圧型多段圧縮式ロータリコンプレッサ１０の第１の回転圧縮要素３２の吸入圧（低圧）と、密閉容器１２内の中間圧（ケース内圧）と、第２の回転圧縮要素３４が吐出する高圧（吐出圧）を示し、図５は単気筒のロータリコンプレッサの場合に同様の高圧を密閉容器内に吐出した場合の蒸発温度に対する吸入圧と高圧（ケース内圧）を示している。両図からも明らかな如く、本発明の内部中間圧型多段圧縮式ロータリコンプレッサ１０では、密閉容器内の圧力は単気筒のロータリコンプレッサの場合に比較して著しく低くなる。このため、密閉容器１２内に封入する冷媒量を減らすことができるようになるものである。
【００４２】
更に、実施例では、第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積の比を大きく、例えば、第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積の比を６０％以上９０％以下に設定している。図５のＢは６０％の場合の中間圧と、Ａは９０％の場合の中間圧を示している。
【００４３】
従来多段圧縮式ロータリコンプレッサにおいて、第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積の比は５７％程度であったが、このような値とした場合、中間圧が高くなり、これによって密閉容器１２内に吐出される冷媒のガス密度も高くなるため、ロータリコンプレッサ１０に封入する冷媒量も多くしなければならないが、実施例のように第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積の比を６０％以上とすれば、密閉容器１２内の冷媒量が少なくなる。
【００４４】
また、第１の回転圧縮要素３２に対する第２の回転圧縮要素３４の排除容積の比を９０％より大きくした場合には、図５からも明らかな如く第１の回転圧縮要素に吸入される冷媒の圧力（吸入圧）と密閉容器１２内の中間圧が殆ど同じ圧力になるため、第１の回転圧縮要素３２で充分に圧縮されなくなり、または、第１の回転圧縮要素３２のベーンの付勢力が不足してベーン飛びが生じる。また、密閉容器１２内底部に設けられたオイル溜めからのオイルの差圧給油が充分に行えなくなるなど、ロータリコンプレッサ１０の挙動が不安定になるという問題が生じる。
【００４５】
従って、第１の回転圧縮要素３２に対する第２の回転圧縮要素３４の排除容積の比を実施例の如く６０％以上９０％以下とすることで、第２の回転圧縮要素３４のベーン飛び等の不安定な運転挙動を回避しながら、１段目の差圧（第１の回転圧縮要素３２の吸込圧力（吸入圧）と第１の回転圧縮要素３２の吐出圧力（中間圧））を小さくして、密閉容器１２内に吐出される冷媒ガスの密度を低くすることができるようになる。
【００４６】
即ち、密閉容器１２内に吐出されるガス密度が低くなることにより、密閉容器１２内にある冷媒ガスの量をより一層減らすことができるようになるので、密閉容器１２内に封入する冷媒ガスの量を削減することができるようになる。
【００４７】
また、上部カバー６６は第２の回転圧縮要素３４の上シリンダ３８内部と吐出ポート３９にて連通する吐出消音室６２を画成し、この上部カバー６６の上側には、上部カバー６６と所定間隔を存して、電動要素１４が設けられている。この上部カバー６６は前記上部支持部材５４の軸受け５４Ａが貫通する孔が形成された略ドーナッツ状の円形鋼板から構成されている。
【００４８】
そして、この場合冷媒として、本実施例では可燃性冷媒であるプロパン（Ｒ２９０）を使用している。尚、本発明に適応可能な他の可燃性冷媒としてはイソブタン（Ｒ６００ａ）やＡＳＨＲＡＥ　Ｓｔｄ　３４　Ｓａｆｅｔｙ　ｇｒｏｕｐに基づき、高燃焼性（Ｌｅｖｅｌ３）と区分されている冷媒であるメタン（Ｒ５０）、エタン（Ｒ１７０）、プロパン（Ｒ２９０）、ブタン（Ｒ６００）、プロピレン（Ｒ１２７０）等があげられる。
【００４９】
また、密閉容器１２の容器本体１２Ａの側面には、シリンダ３８、４０の吸込通路５８、６０、シリンダ３８の吸込通路５８とは反対側、ロータ２４の下側（電動要素１４の直下）に対応する位置に、スリーブ１４１、１４２、１４３及び１４４がそれぞれ溶接固定されている。スリーブ１４１と１４２は上下に隣接すると共に、スリーブ１４３はスリーブ１４１の略対角線上にある。また、スリーブ１４４はスリーブ１４１の上方に位置する。
【００５０】
そして、スリーブ１４１内には上シリンダ３８に冷媒ガスを導入するための冷媒導入管９２の一端が挿入接続され、この冷媒導入管９２の一端は上シリンダ３８の吸込通路５８と連通する。この冷媒導入管９２は密閉容器１２の外側を通過してスリーブ１４４に至り、他端はスリーブ１４４内に挿入接続されて密閉容器１２内に連通する。
【００５１】
また、スリーブ１４２内には下シリンダ４０に冷媒ガスを導入するための冷媒導入管９４の一端が挿入接続され、この冷媒導入管９４の一端は下シリンダ４０の吸込通路６０と連通する。また、スリーブ１４３内には冷媒吐出管９６が挿入接続され、この冷媒導入管９６の一端は吐出消音室６２と連通する。
【００５２】
以上の構成で次に動作を説明する。ターミナル２０及び図示されない配線を介して電動要素１４のステータコイル２８に商用電源が通電されると、電動要素１４が起動してロータ２４が回転する。この回転により回転軸１６と一体に設けられた上下偏心部４２、４４に嵌合されて上下ローラ４６、４８が上下シリンダ３８、４０内を偏心回転する。
【００５３】
これにより、冷媒導入管９４及びシリンダ４０に形成された吸込通路６０を経由して図示しない吸込ポートから下シリンダ４０の低圧室側に吸入された低圧（第１の回転回転圧縮要素３２の吸入圧：３８０ＫＰａ）の冷媒は、ローラ４８とベーン５２の動作により圧縮されて中間圧となり下シリンダ４０の高圧室側より図示しない吐出ポート、下部支持部材５６に形成された吐出消音室６４から図示しない連通路を経て中間吐出管１２１から密閉容器１２内に吐出される。これによって、密閉容器１２内は中間圧（第１の回転圧縮要素３２の吐出圧力：第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積比を６０％とした場合は７１０ＫＰａ、第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積比を９０％とした場合は４５０ＫＰａ）となる。
【００５４】
そして、密閉容器１２内の中間圧の冷媒ガスは、スリーブ１４４から出て冷媒導入管９２及びシリンダ３８に形成された吸込通路５８を経由して図示しない吸込ポートから上シリンダ３８の低圧室側に吸入される。吸入された中間圧の冷媒ガスは、ローラ４６とベーン５０の動作により２段目の圧縮が行われて高温高圧の冷媒ガスとなる（第２の回転圧縮要素３４の吐出圧力（高圧）：１８９０ＫＰａ）。これにより、吐出消音室６２内に設けられた吐出弁１２７が開放され、吐出消音室６２と吐出ポート３９とが連通するため、上シリンダ３８の高圧室側から吐出ポート３９内を通り上部支持部材５４に形成された吐出消音室６２に吐出される。
【００５５】
そして、吐出消音室６２に吐出された高圧の冷媒ガスの一部は、前述する連通路９０から第２の背圧室８０内に流入して、ベーン５０をローラ４６側に付勢する。更に、中間仕切板３６に形成された連通孔１１０を経て第１の背圧室８２内に流入して、ベーン５２をローラ４８側に付勢する。他方、吐出消音室６２内に吐出された他の冷媒ガスは冷媒吐出管９６を経て外部に吐出される。
【００５６】
ここで、ロータリコンプレッサ１０の運転が停止すると、吐出消音室６２と第２の回転圧縮要素３４の第２の背圧室８０とが連通路９０にて連通され、第１の回転圧縮要素３２の第１の背圧室８２と第２の回転圧縮要素３４の第２の背圧室８０とが連通孔１１０にて連通されているため、これら背圧室８０、８２からベーン５０、５２と案内溝７０、７２及びスプリング７４、７６と収納部７０Ａ、７２Ａの隙間を通ってシリンダ３８内の高圧の冷媒ガスがシリンダ４０にバイパスされる。これにより、シリンダ３８内の高圧の冷媒ガスは短時間で平衡圧に達する。
【００５７】
また、ロータリコンプレッサ１０の停止後、吐出消音室６２の圧力が低下して密閉容器１２内の圧力より低くなると、前述する如く均圧弁１０１が密閉容器１２内の圧力により下方に押されて均圧用通路１００を開放する。これにより、密閉容器１２内の中間圧の冷媒ガスが吐出消音室６２内に流入する。
【００５８】
係る圧力導入によって吐出消音室６２内の圧力が上昇し、吐出消音室６２内の圧力が密閉容器１２内の圧力と同じ圧力となると、前述の如く均圧弁１０１が均圧用通路１００を閉じる。一方、吐出消音室６２と各背圧室８０、８２内は連通路９０及び連通孔１１０にて連通しているので、これらにより、密閉容器１２内、吐出消音室６２、背圧室８０、８２、各シリンダ４０、３８内の圧力は迅速に平衡することになる。従って、次回の再起動時における始動性が改善される。
【００５９】
このように、冷媒として可燃性冷媒を用い、第１の回転圧縮要素３２で圧縮された冷媒を密閉容器１２内に吐出し、この吐出された中間圧の冷媒を第２の回転圧縮要素３４で圧縮すると共に、第２の回転圧縮要素３４の吐出消音室６２と第２の背圧室８０とを連通路９０で連通し、更に、第２の背圧室８０と第１の背圧室８２とを中間仕切板３６に形成した連通孔１１０にて連通させたので、第１及び第２の背圧室８０、８２に吐出消音室６２の高圧の冷媒ガスが加えられる。
【００６０】
これにより、係る内部中間圧型のロータリコンプレッサ１０を使用した場合にも、ベーン５０、５２がローラ４６、４８側に充分に付勢されるので、ベーン飛び等の第１及び第２の回転圧縮要素３２、３４の不安定な運転挙動を回避することができるようになる。
【００６１】
特に、本発明では密閉容器１２内を中間圧とすると共に、後述する如く密閉容器１２内の中間圧が低くなるように第１の回転圧縮要素３２の排除容積に対する第２の回転圧縮要素３４の排除容積の比を大きく設定しているので、ロータリコンプレッサ１０の起動時に、密閉容器１２内の圧力が上がりにくなるが、背圧室８０、８２には第２の回転圧縮要素３４から吐出される高圧が加えられるので、始動時からベーン５２に充分な背圧がかかるようになり、ロータリコンプレッサ１０の信頼性の向上を図ることができるようになる。
【００６２】
また、ロータリコンプレッサ１０の運転を停止後には、前述する如く吐出消音室６２内と第２の背圧室８０とが連通路９０にて連通されており、第２の背圧室８０と第１の背圧室８２とが連通孔１１０にて連通されていると共に、密閉容器１２内と吐出消音室６２内とが均圧用通路１００にて連通されるので、ロータリコンプレッサ１０内が平衡圧に達するのを早めることができる。
【００６３】
これにより、ロータリコンプレッサ１０内の差圧を短時間でなくすことができるようになり、ロータリコンプレッサ１０の始動性を著しく高めることができるようになる。
【００６４】
尚、実施例では回転軸１６を縦置型とした多段圧縮式ロータリコンプレッサ１０について説明したが、この発明は回転軸を横置型とした多段圧縮式ロータリコンプレッサにも適応できることは云うまでもない。
【００６５】
更に、多段圧縮式ロータリコンプレッサを第１及び第２の回転圧縮要素を備えた２段圧縮式ロータリコンプレッサで説明したが、これに限らず回転圧縮要素を３段、４段或いはそれ以上の回転圧縮要素を備えた多段圧縮式ロータリコンプレッサに適応しても差し支えない。
【００６６】
【発明の効果】
以上詳述した如く請求項１の発明によれば、第１及び第２の回転圧縮要素を構成する第１及び第２のシリンダと、電動要素の回転軸に形成された偏心部により各シリンダ内でそれぞれ偏心回転する第１及び第２のローラと、各ローラに当接して各シリンダ内を低圧室側と高圧室側にそれぞれ区画する第１及び第２のベーンと、各ベーンを常時各ローラ側に付勢するための第１及び第２の背圧室とを備え、冷媒として可燃性冷媒を用い、第１の回転圧縮要素で圧縮された冷媒を密閉容器内に吐出し、この吐出された中間圧の冷媒を第２の回転圧縮要素で圧縮すると共に、第２の回転圧縮要素の冷媒吐出側と第１及び第２の背圧室とを連通させたので、第１及び第２の背圧室に第２の回転圧縮要素で圧縮された高圧の冷媒が加えられる。
【００６７】
これにより、第１及び第２の背圧室に第２の回転圧縮要素で圧縮された高圧の冷媒ガスが加えられるので、ロータリコンプレッサの始動時から迅速に背圧が上昇するようになり、ベーン飛び等の不安定な運転挙動を回避することができるようになる。これにより、ロータリコンプレッサの信頼性の向上を図ることができるようになる。
【００６８】
請求項２の発明では上記発明に加えて、第２のシリンダの開口面を閉塞する支持部材と、この支持部材内に構成され、第２のシリンダ内で圧縮された冷媒が吐出される吐出消音室と、支持部材内に形成され、吐出消音室と第２の背圧室とを連通する連通路と、第１及び第２のシリンダ間に狭持された中間仕切板と、この中間仕切板内に形成され、第２の背圧室と第１の背圧室とを連通する連通孔とを備えたので、簡単な構造で第２の回転圧縮要素の冷媒吐出側の高圧が第１及び第２の背圧室に加えられるようになる。これにより、加工性が向上し、生産コストの低減を図ることができるようになる。
【００６９】
そして、請求項３の発明では請求項２の発明に加えて、吐出消音室と密閉容器内とを連通する均圧用通路と、この均圧用通路を開閉する均圧弁とを備え、この均圧弁は、吐出消音室内の圧力が密閉容器内の圧力より低くなった場合に均圧用通路を開放するので、ロータリコンプレッサ停止後の第１の回転圧縮要素と第２の回転圧縮要素及び密閉容器内の圧力の平衡を早めることができるようになる。
【００７０】
これにより、ロータリコンプレッサ内の高低圧差を短時間で解消することができるようになり、ロータリコンプレッサの始動性を著しく高めることができるようになる。
【００７１】
更に、請求項４の発明では、冷媒として可燃性冷媒を用い、第１の回転圧縮要素で圧縮された冷媒を密閉容器内に吐出し、この吐出された中間圧の冷媒を第２の回転圧縮要素で圧縮すると共に、第２の回転圧縮要素の冷媒吐出側の圧力が密閉容器内の圧力より低くなった場合に、当該第２の回転圧縮要素の冷媒吐出側と密閉容器内とを連通させる均圧弁を備えるので、コンプレッサ停止後に、第１の回転圧縮要素と第２の回転圧縮要素及び密閉容器内の圧力の平衡を早めることができるようになる。
【００７２】
これにより、ロータリコンプレッサ内の高低圧差を短時間で解消することができるようになり、ロータリコンプレッサの始動性を著しく高めることができるようになる。
【００７３】
請求項５の発明では請求項４の発明に加えて、第２の回転圧縮要素を構成するシリンダと、このシリンダの開口面を閉塞する支持部材と、この支持部材内に構成され、シリンダ内で圧縮された冷媒が吐出される吐出消音室と、この吐出消音室と密閉容器内とを区画するカバーと、このカバー内に形成された均圧用通路とを備え、均圧弁は、吐出消音室内に設けられて均圧用通路を開閉するので、生産性とスペース効率を改善することができるようになるものである。
【図面の簡単な説明】
【図１】本発明の実施例の内部中間圧型多段圧縮式ロータリコンプレッサの縦断面図である。
【図２】本発明の内部中間圧型多段圧縮式ロータリコンプレッサの第１及び第２の回転圧縮機構部の拡大縦断面図である。
【図３】本発明の第２の回転圧縮要素の吐出消音室の拡大縦断面図である。
【図４】本発明の内部中間圧型多段圧縮式ロータリコンプレッサにおける蒸発温度に対する吸入圧と中間圧と高圧の関係を示す図である。
【図５】単気筒のロータリコンプレッサにおける蒸発温度に対する吸入圧と高圧の関係を示す図である。
【符号の説明】
１０　多段圧縮式ロータリコンプレッサ
１２　密閉容器
１４　電動要素
１６　回転軸
１８　回転圧縮機構部
２２　ステータ
２４　ロータ
２６　積層体
２８　ステータコイル
３０　積層体
３２　第１の回転圧縮要素
３４　第２の回転圧縮要素
３８、４０　シリンダ
５４　上部支持部材
５６　下部支持部材
６２、６４　吐出消音室
６５　カップ
６６　上部カバー
８０　第２の背圧室
８２　第１の背圧室
９０　連通路
１００　均圧用通路
１０１　均圧弁
１１０　連通孔[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention includes an electric element in a closed vessel, and first and second rotary compression elements driven by a rotation shaft of the electric element, and supplies a refrigerant compressed by the first rotary compression element to a second rotary compression element. The present invention relates to a multi-stage compression type rotary compressor that compresses with a rotary compression element.
[0002]
[Prior art]
Conventionally, in this type of rotary compressor, a refrigerant gas is sucked into a low pressure chamber side of a cylinder from a suction port of a rotary compression element, compressed by the operation of rollers and vanes, and then temporarily discharged into a closed container from a discharge port of a cylinder high pressure chamber. The air is discharged from the closed container to the outside. The vane is movably mounted in a groove provided in a radial direction of the cylinder. The vane is pressed against a roller to partition the inside of the cylinder into a low-pressure chamber and a high-pressure chamber. A spring for urging the vane toward the roller is provided on the rear side of the vane, and a back pressure chamber communicating with the inside of a sealed container for urging the vane toward the roller is provided in the groove. Then, the high pressure in the closed vessel is applied to the back pressure chamber to urge the vane toward the roller.
[0003]
On the other hand, in recent years, the use of HC refrigerant other than Freon, for example, a flammable refrigerant such as propane (R290) has been studied in this type of rotary compressor due to the problem of destruction of the ozone layer by Freon refrigerant.
[0004]
By the way, the amount of flammable refrigerant such as propane must be reduced as much as possible from the viewpoint of safety and the like. Normally, when propane is used as a refrigerant, the safety limit is about 150 g, and in practice, it is necessary to suppress it to about 100 g (50 g for refrigerators) with a margin.
[0005]
On the other hand, in the rotary compressor, the compressed refrigerant is discharged into the closed container, so that the amount of refrigerant to be charged increases by about 30 g to 50 g as compared with a reciprocating compressor of the same capacity. Therefore, the practical application of the rotary compressor using the flammable refrigerant has been extremely severe.
[0006]
[Problems to be solved by the invention]
Therefore, the use of a flammable refrigerant in a multi-stage compression type rotary compressor in which the pressure inside the sealed container is an intermediate pressure has been studied. In this case, the pressure in the closed container is lower than in the case where high-pressure refrigerant is discharged into the closed container. In other words, the lower the pressure, the lower the density of the refrigerant, so that the amount of the refrigerant present in the closed container decreases, and the amount of the refrigerant sealed in the closed container can be reduced. In particular, when the ratio of the excluded volume of the second rotary compression element to the excluded volume of the first rotary compression element is increased, the intermediate pressure becomes difficult to increase, so that the amount of the refrigerant sealed in the closed container is further increased. Can be reduced.
[0007]
However, when the inside pressure of the closed vessel of the rotary compressor is set to the intermediate pressure and the intermediate pressure is suppressed as described above, the pressure in the closed vessel applied as the back pressure to the vane of the first rotary compression element at the time of starting the compressor is unlikely to increase. Therefore, there was a risk of vane jumping.
[0008]
In addition, in the case of the internal intermediate pressure type, since it takes time for the inside of the compressor to reach an equilibrium pressure after the rotary compressor is stopped, there has been a problem that startability is deteriorated at the time of restart.
[0009]
The present invention has been made in order to solve the problems of the related art, and avoids unstable operation behavior such as vane flying when a combustible refrigerant is used for an internal intermediate pressure type multi-stage compression type rotary compressor. Another object of the present invention is to improve the startability of a compressor.
[0010]
[Means for Solving the Problems]
That is, in the multi-stage compression type rotary compressor of the present invention, each of the first and second cylinders forming the first and second rotary compression elements and the eccentric portion formed on the rotation shaft of the electric element are provided in each cylinder. First and second rollers that rotate eccentrically, first and second vanes that abut against each roller to partition the inside of each cylinder into a low-pressure chamber side and a high-pressure chamber side, and that each vane is always on each roller side. First and second back pressure chambers for biasing, using a flammable refrigerant as a refrigerant, discharging the refrigerant compressed by the first rotary compression element into a closed container, Since the pressure of the refrigerant is compressed by the second rotary compression element and the refrigerant discharge side of the second rotary compression element communicates with the first and second back pressure chambers, the first and second back pressure High-pressure refrigerant compressed by the second rotary compression element is added to the chamber
[0011]
According to the second aspect of the present invention, in addition to the above-mentioned invention, a support member for closing an opening surface of the second cylinder, and a discharge muffling device configured in the support member and discharging the refrigerant compressed in the second cylinder Chamber, a communication passage formed in the support member and communicating the discharge muffling chamber and the second back pressure chamber, an intermediate partition plate sandwiched between the first and second cylinders, and the intermediate partition plate And a communication hole for communicating the second back pressure chamber and the first back pressure chamber, so that the pressure of the second rotary compression element on the refrigerant discharge side can be reduced by a relatively simple structure. It will be applied to the first and second back pressure chambers.
[0012]
According to a third aspect of the present invention, in addition to the second aspect of the present invention, there is provided a pressure equalizing passage for communicating the discharge muffling chamber with the inside of the closed container, and a pressure equalizing valve for opening and closing the pressure equalizing passage. Since the pressure equalizing passage is opened when the pressure in the sound deadening chamber becomes lower than the pressure in the closed container, the pressure equalization in the first rotary compression element, the second rotary compression element and the closed container can be accelerated. become.
[0013]
According to the fourth aspect of the invention, a flammable refrigerant is used as the refrigerant, the refrigerant compressed by the first rotary compression element is discharged into the closed container, and the discharged intermediate-pressure refrigerant is discharged by the second rotary compression element. Equalizing valve for compressing and communicating between the refrigerant discharge side of the second rotary compression element and the inside of the closed vessel when the pressure on the refrigerant discharge side of the second rotary compression element becomes lower than the pressure in the closed vessel. Therefore, after the compressor is stopped, the pressure equalization in the closed container can be accelerated.
[0014]
According to a fifth aspect of the present invention, in addition to the fourth aspect, a cylinder constituting the second rotary compression element, a support member for closing an opening surface of the cylinder, and a support member formed in the support member and having a A discharge silence chamber from which the compressed refrigerant is discharged, a cover that partitions the discharge silence chamber and the inside of the closed container, and a pressure equalizing passage formed in the cover, and a pressure equalizing valve is provided in the discharge silence chamber. Since the pressure equalizing passage is provided to open and close, the structure can be simplified and the space efficiency can be improved.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of an internal intermediate pressure type multi-stage (two-stage) compression type rotary compressor 10 having first and second rotary compression elements 32 and 34 as an embodiment of a multi-stage compression type rotary compressor of the present invention. ing.
[0016]
In FIG. 1, a rotary compressor 10 of the embodiment is an internal intermediate pressure type multistage compression type rotary compressor using propane (R290) as a refrigerant. The multistage compression type rotary compressor 10 includes a cylindrical hermetic container 12A made of a steel plate, and An airtight container 12 as a case formed by a substantially bowl-shaped end cap (lid) 12B for closing the upper opening of the airtight container 12A, and disposed above the internal space of the container body 12A of the airtight container 12 A rotary compression mechanism portion including a selected electric element 14, and a first rotary compression element 32 and a second rotary compression element 34 disposed below the electric element 14 and driven by the rotation shaft 16 of the electric element 14. 18.
[0017]
The closed container 12 has an oil reservoir at the bottom. A terminal (wiring omitted) 20 for supplying electric power to the electric element 14 is attached to a side surface of the container body 12A.
[0018]
The electric element 14 includes a stator 22 annularly mounted along the inner surface of the upper space of the closed casing 12, and a rotor 24 inserted and installed with a slight gap inside the stator 22. The rotating shaft 16 extending in the vertical direction is fixed to the rotor 24.
[0019]
The stator 22 has a laminated body 26 in which donut-shaped electromagnetic steel sheets are laminated, and a stator coil 28 wound by a distributed winding method. The rotor 24 is also formed of a laminated body 30 of electromagnetic steel sheets, like the stator 22.
[0020]
An intermediate partition plate 36 is sandwiched between the first rotary compression element 32 and the second rotary compression element 34. That is, the first rotary compression element 32 and the second rotary compression element 34 include an intermediate partition plate 36, an upper cylinder (second cylinder) 38 disposed above and below the intermediate partition plate 36, and a lower cylinder (second cylinder). The upper roller (e.g., one cylinder) 40 and the eccentric portions 42 and 44 provided on the rotating shaft 16 so as to rotate the upper and lower cylinders 38 and 40 with a phase difference of 180 degrees. A second roller) 46, a lower roller (first roller) 48, and a vane (second roller) which abuts on the upper and lower rollers 46, 48 to partition the interior of the upper and lower cylinders 38, 40 into a low pressure chamber side and a high pressure chamber side, respectively. And the vane (first vane) 52, and the upper opening surface of the upper cylinder 38 and the lower opening surface of the lower cylinder 40 are closed to support the rotary shaft 16 as a support member. Upper support member 54 and lower support portion Constructed at 56.
[0021]
Guide grooves 70, 72 for accommodating vanes 50, 52 are formed in the upper and lower cylinders 38, 40 constituting the first and second rotary compression elements 32, 34, as shown in FIG. Outside the guide grooves 70 and 72, that is, on the back side of the vanes 50 and 52, storage portions 70A and 72A for storing springs 74 and 76 as spring members are formed. The springs 74 and 76 abut against the rear end portions of the vanes 50 and 52, and constantly bias the vanes 50 and 52 toward the rollers 46 and 48. The storage portions 70A, 72A are open to the guide grooves 70, 72 side and the closed container 12 (container body 12A) side, and the springs 74, 76 stored in the storage portions 70A, 72A are connected to the closed container 12 side. Is provided with a plug (not shown) and serves to prevent the springs 74 and 76 from coming off. An O-ring (not shown) is attached to the peripheral surface of the plug to seal between each plug and the inner surfaces of the storage portions 70A and 72A.
[0022]
In addition, between the guide groove 70 and the storage portion 70A, the second back pressure that applies the refrigerant discharge pressure of the second rotary compression element 34 to the vane 50 to constantly bias the vane 50 together with the spring 74 toward the roller 46 side. A pressure chamber 80 is provided. The upper surface of the second back pressure chamber 80 communicates with a communication passage 90 described later. The lower surface of the second back pressure chamber 80 communicates with a first back pressure chamber 82 described later through a communication hole 110 formed in the intermediate partition plate 36.
[0023]
As described above, the communication between the discharge muffling chamber 62 and the second back pressure chamber 80 through the communication passage 90 allows the high pressure of the high pressure compressed by the second rotary compression element 34 and discharged into the discharge muffling chamber 62. Refrigerant is added to the second back pressure chamber 80 from the communication passage 90. As a result, the vane 50 is sufficiently urged toward the roller 46, so that unstable operation behavior of the second rotary compression element 34 such as vane jump can be avoided.
[0024]
Between the guide groove 72 for accommodating the vane 52 of the lower cylinder 40 and the accommodating portion 72A, the first back pressure chamber 82 for urging the vane 52 to the roller 48 side together with the spring 76 is provided. ing. The upper surface of the first back pressure chamber 82 communicates with the second back pressure chamber 80 through the communication hole 110 described above.
[0025]
As described above, the communication between the second back pressure chamber 80 and the first back pressure chamber 82 through the communication hole 110 allows the discharge muffling chamber to be added to the second back pressure chamber 80 via the communication passage 90. The high pressure in 62 can be introduced into the first back pressure chamber 82. As a result, the vane 52 is sufficiently urged toward the roller 48, so that the pressure in the first back pressure chamber 82 rises quickly at the time of start-up, and the first rotary compression element 32 such as a vane jumps. Unstable driving behavior can be avoided.
[0026]
In particular, in the present invention, the inside pressure of the second rotary compression element 34 with respect to the excluded volume of the first rotary compression element 32 is set so that the pressure inside the closed container 12 is set to the intermediate pressure and the intermediate pressure inside the closed container 12 is reduced as described later. Since the ratio of the exclusion volumes is set to be large, it is possible to avoid a disadvantage that sufficient back pressure is not applied to the vane 52 because the pressure in the closed vessel 12 does not easily increase when the rotary compressor 10 is started. Become like Thereby, the reliability of the rotary compressor 10 can be improved.
[0027]
In addition, by merely forming the communication passage 90 in the upper support member 54 and forming the communication hole 110 in the intermediate partition plate 36, sufficient back pressure can be applied to each of the vanes 50 and 52 without using a special mechanism. As a result, a highly reliable rotary compressor 10 can be produced while reducing processing costs.
[0028]
The upper and lower cylinders 38 and 40 are provided with suction passages 58 and 60 that communicate with the insides of the upper and lower cylinders 38 and 40 through suction ports (not shown). Further, the upper support member 54 is provided with a discharge muffling chamber 62 formed by closing the recessed portion of the upper support member 54 from the discharge port 39 with the cover serving as a wall for the refrigerant compressed in the upper cylinder 38. ing. That is, the discharge muffling chamber 62 is closed by the upper cover 66 as a wall defining the discharge muffling chamber 62.
[0029]
The communication path 90 described above is formed in the upper support member 54. The communication passage 90 is a passage that communicates between the discharge muffling chamber 62 communicating with the discharge port 39 of the upper cylinder 38 of the second rotary compression element 34 and the second back pressure chamber 80.
[0030]
Further, the upper cover 66 is formed with a pressure equalizing passage 100 that communicates the inside of the closed container 12 and the inside of the discharge muffling chamber 62 as shown in FIG. The pressure equalizing passage 100 is a hole vertically penetrating the upper cover 66, and the lower surface of the pressure equalizing passage 100 is closed by a pressure equalizing valve 101 mounted in the discharge muffling chamber 62 so as to be opened and closed.
[0031]
The pressure equalizing valve 101 is made of an elastic member made of a metal plate having a vertically long and substantially rectangular shape. A backer valve 102 as a pressure equalizing valve suppressing plate is disposed below the pressure equalizing valve 101. Attached to. One side of the pressure equalizing valve 101 is in contact with the pressure equalizing passage 100 to be sealed, and the other side is fixed to the mounting hole 103 of the upper cover 66 provided at a predetermined distance from the pressure equalizing passage 100 by a caulking pin 104. Have been.
[0032]
When the pressure in the discharge muffling chamber 62 becomes lower than the pressure in the closed container 12 after the rotary compressor 10 stops, the pressure in the closed container 12 pushes the equalizing valve 101 closing the equalizing passage 100 from above in FIG. The pressure equalizing passage 100 is opened to discharge the pressure to the discharge muffling chamber 62. At this time, because the other side of the equalizing valve 101 is fixed to the upper cover 66, one side of the equalizing valve 100 that is in contact with the equalizing passage 100 is warped down and abuts on the backer valve 102 that regulates the opening amount of the equalizing valve. When the pressure in the discharge muffling chamber 62 becomes equal to or higher than the pressure in the closed container 12, the equalizing valve 101 separates from the backer valve 102 and closes the equalizing passage 100.
[0033]
As described above, when the pressure in the discharge muffling chamber 62 becomes lower than the pressure in the closed vessel 12, the pressure equalizing passage 100 is opened to discharge the pressure to the discharge muffle chamber 62. The inconvenience that the intermediate pressure is not easily reduced can be avoided. As a result, the pressure in the discharge muffling chamber 62 and the pressure in the closed container 12 can be quickened.
[0034]
Further, since the pressure equalizing valve 101 is provided in the discharge muffling chamber 62, interference does not occur even when the upper electric element 14 approaches the upper cover 66. Therefore, space efficiency is improved, and the rotary compressor 10 can be reduced in size. Further, since the pressure equalizing valve 101 is mounted on the lower surface of the upper cover 66, the mounting operation can be easily performed.
[0035]
Further, on the lower surface of the discharge muffling chamber 62, a discharge valve 127 that closes the discharge port 39 so as to be able to open and close is provided (not shown in FIGS. 1 and 2). The discharge valve 127 is formed of an elastic member made of a metal plate having a vertically long and substantially rectangular shape. A backer valve 128 as a discharge valve suppressing plate is disposed above the discharge valve 127 and attached to the upper support member 54. Have been. One side of the discharge valve 127 is in contact with the discharge port 39 to seal it, and the other side is fixed to the mounting hole 129 of the upper support member 54 provided at a predetermined distance from the discharge port 39 by a caulking pin 130. ing.
[0036]
Then, the refrigerant gas that has been compressed in the upper cylinder 38 and reached a predetermined pressure pushes up the discharge valve 127 closing the discharge port 39 from below in the drawing to open the discharge port 39 and discharge the gas to the discharge muffle chamber 62. . At this time, since the other side of the discharge valve 127 is fixed to the upper support member 54, one side in contact with the discharge port 39 is warped up, and the discharge valve 127 contacts a backer valve (not shown) regulating the opening amount of the discharge valve 127. Touch When it is time to end the discharge of the refrigerant gas, the discharge valve 127 separates from the backer valve and closes the discharge port 39.
[0037]
On the other hand, the refrigerant gas compressed in the lower cylinder 40 is discharged from a discharge port (not shown) to a discharge muffling chamber 64 formed on the lower support member 56 on the side opposite to the electric element 14 (the bottom side of the sealed container 12). . The discharge muffling chamber 64 has a hole at the center thereof through which the lower shaft 56 and the lower support member 56 which also serves as the bearing of the above-mentioned rotary shaft 16 penetrates, and the lower support member 56 on the side opposite to the electric element 14. It is composed of a covering cup 65.
[0038]
In this case, a bearing 54 </ b> A is formed upright at the center of the upper support member 54. A bearing 56A is formed through the center of the lower support member 56, and the rotating shaft 16 is held by a bearing 54A of the upper support member 54 and a bearing 56A of the lower support member 56.
[0039]
The discharge muffling chamber 64 of the first rotary compression element 32 communicates with the inside of the closed container 12 through a communication passage, which communicates with the lower support member 56, the upper support member 54, the upper cover 66, the upper and lower cylinders. 38, 40, and holes (not shown) penetrating the intermediate partition plate 36. In this case, an intermediate discharge pipe 121 is provided upright at the upper end of the communication path, and an intermediate-pressure refrigerant is discharged from the intermediate discharge pipe 121 into the closed container 12.
[0040]
As described above, since the intermediate-pressure refrigerant gas compressed by the first rotary compression element 32 is discharged into the closed container 12, compared with the case where the high-pressure refrigerant is discharged into the closed container 12, The amount of refrigerant to be discharged decreases. That is, since the density of the refrigerant is lower as the pressure is lower, discharging the intermediate-pressure refrigerant into the closed container 12 is more preferable than discharging the high-pressure refrigerant into the closed container 12, and the gas density of the refrigerant is lower. The amount of refrigerant present in the closed container 12 is reduced.
[0041]
This situation will be described with reference to FIGS. FIG. 4 shows the suction pressure (low pressure) of the first rotary compression element 32 of the internal intermediate pressure type multistage compression rotary compressor 10 according to the present invention, the intermediate pressure in the closed vessel 12 (case internal pressure), 5 shows the high pressure (discharge pressure) discharged by the rotary compression element 34, and FIG. 5 shows the suction pressure and the high pressure (case internal pressure) with respect to the evaporation temperature when the same high pressure is discharged into a closed container in the case of a single cylinder rotary compressor. ). As is clear from both figures, in the internal intermediate pressure type multi-stage compression type rotary compressor 10 of the present invention, the pressure in the closed vessel is significantly lower than that of the single cylinder rotary compressor. For this reason, the amount of the refrigerant sealed in the closed container 12 can be reduced.
[0042]
Furthermore, in the embodiment, the ratio of the displacement volume of the second rotary compression element 34 to the displacement volume of the first rotary compression element 32 is increased, for example, the second rotational compression to the displacement volume of the first rotary compression element 32. The ratio of the excluded volume of the element 34 is set to 60% or more and 90% or less. FIG. 5B shows the intermediate pressure at 60%, and FIG. 5A shows the intermediate pressure at 90%.
[0043]
In the conventional multi-stage compression type rotary compressor, the ratio of the displacement volume of the second rotary compression element 34 to the displacement volume of the first rotary compression element 32 is about 57%. And the gas density of the refrigerant discharged into the closed container 12 also increases, so that the amount of refrigerant to be filled in the rotary compressor 10 must be increased. However, as in the embodiment, the first rotary compression element If the ratio of the excluded volume of the second rotary compression element 34 to the excluded volume of 32 is set to 60% or more, the amount of refrigerant in the closed container 12 decreases.
[0044]
Further, when the ratio of the displacement volume of the second rotary compression element 34 to the first rotary compression element 32 is set to be larger than 90%, the refrigerant sucked into the first rotary compression element as is clear from FIG. Pressure (suction pressure) and the intermediate pressure in the sealed container 12 are almost the same pressure, so that the first rotary compression element 32 is not sufficiently compressed or the vane biasing force of the first rotary compression element 32 Shortage causes vane jump. In addition, there arises a problem that the behavior of the rotary compressor 10 becomes unstable, for example, it is not possible to sufficiently supply the differential pressure of the oil from the oil reservoir provided at the bottom of the closed container 12.
[0045]
Therefore, by setting the ratio of the excluded volume of the second rotary compression element 34 to the first rotary compression element 32 to be 60% or more and 90% or less as in the embodiment, the second rotary compression element 34 can prevent vane jump or the like. The first-stage differential pressure (the suction pressure (suction pressure) of the first rotary compression element 32 and the discharge pressure (intermediate pressure) of the first rotary compression element 32) is reduced while avoiding unstable operation behavior. Thus, the density of the refrigerant gas discharged into the closed container 12 can be reduced.
[0046]
That is, since the gas density discharged into the closed container 12 becomes lower, the amount of the refrigerant gas in the closed container 12 can be further reduced. The amount can be reduced.
[0047]
The upper cover 66 defines a discharge muffling chamber 62 that communicates with the inside of the upper cylinder 38 of the second rotary compression element 34 at the discharge port 39. Above the upper cover 66, a predetermined distance from the upper cover 66 is provided. Therefore, the electric element 14 is provided. The upper cover 66 is made of a substantially donut-shaped circular steel plate having a hole through which the bearing 54A of the upper support member 54 penetrates.
[0048]
In this case, propane (R290), which is a combustible refrigerant, is used as the refrigerant in this embodiment. Other flammable refrigerants applicable to the present invention include methane (R50) and ethane (R170), which are classified as highly flammable (Level 3) based on isobutane (R600a) or ASHRAE Std 34 Safety group. ), Propane (R290), butane (R600), propylene (R1270) and the like.
[0049]
The side surfaces of the container body 12A of the closed container 12 correspond to the suction passages 58, 60 of the cylinders 38, 40, the side opposite to the suction passage 58 of the cylinder 38, and the lower side of the rotor 24 (directly below the electric element 14). The sleeves 141, 142, 143, and 144 are respectively fixed by welding at the positions where they do. The sleeves 141 and 142 are vertically adjacent to each other, and the sleeve 143 is substantially on a diagonal line of the sleeve 141. The sleeve 144 is located above the sleeve 141.
[0050]
One end of a refrigerant introduction pipe 92 for introducing refrigerant gas into the upper cylinder 38 is inserted and connected into the sleeve 141, and one end of the refrigerant introduction pipe 92 communicates with the suction passage 58 of the upper cylinder 38. The refrigerant introduction pipe 92 passes through the outside of the closed container 12 to reach the sleeve 144, and the other end is inserted and connected into the sleeve 144 and communicates with the inside of the closed container 12.
[0051]
One end of a refrigerant introduction pipe 94 for introducing refrigerant gas into the lower cylinder 40 is inserted and connected into the sleeve 142, and one end of the refrigerant introduction pipe 94 communicates with the suction passage 60 of the lower cylinder 40. A coolant discharge pipe 96 is inserted and connected into the sleeve 143, and one end of the coolant introduction pipe 96 communicates with the discharge muffling chamber 62.
[0052]
Next, the operation of the above configuration will be described. When commercial power is supplied to the stator coil 28 of the electric element 14 via the terminal 20 and the wiring (not shown), the electric element 14 starts and the rotor 24 rotates. By this rotation, the upper and lower rollers 46 and 48 are eccentrically rotated in the upper and lower cylinders 38 and 40 by being fitted to the upper and lower eccentric portions 42 and 44 provided integrally with the rotating shaft 16.
[0053]
Accordingly, the low pressure (the suction pressure of the first rotary compression element 32) is drawn into the low pressure chamber side of the lower cylinder 40 from a suction port (not shown) via the refrigerant introduction pipe 94 and the suction passage 60 formed in the cylinder 40. : 380 KPa) is compressed by the operation of the roller 48 and the vane 52 and becomes an intermediate pressure, from the high pressure chamber side of the lower cylinder 40 to a discharge port (not shown) and a discharge silence chamber 64 formed in the lower support member 56 from a connection (not shown) The air is discharged from the intermediate discharge pipe 121 into the closed container 12 through the passage. Accordingly, the inside of the sealed container 12 is set at an intermediate pressure (discharge pressure of the first rotary compression element 32: 60% of the excluded volume ratio of the second rotary compression element 34 to the excluded volume of the first rotary compression element 32). Is 710 KPa, or 450 KPa when the excluded volume ratio of the second rotary compression element 34 to the excluded volume of the first rotary compression element 32 is 90%.
[0054]
Then, the intermediate-pressure refrigerant gas in the sealed container 12 exits from the sleeve 144 and passes through the refrigerant introduction pipe 92 and the suction passage 58 formed in the cylinder 38 to a low-pressure chamber side of the upper cylinder 38 from a suction port (not shown). Inhaled. The sucked intermediate-pressure refrigerant gas is compressed in the second stage by the operation of the rollers 46 and the vanes 50 to become a high-temperature and high-pressure refrigerant gas (discharge pressure (high pressure) of the second rotary compression element 34: 1890 KPa). ). As a result, the discharge valve 127 provided in the discharge muffle chamber 62 is opened, and the discharge muffle chamber 62 communicates with the discharge port 39. Therefore, the upper support member passes through the discharge port 39 from the high pressure chamber side of the upper cylinder 38. The liquid is discharged to the discharge muffling chamber 62 formed at 54.
[0055]
Then, a part of the high-pressure refrigerant gas discharged into the discharge muffling chamber 62 flows into the second back pressure chamber 80 from the communication path 90 described above, and urges the vane 50 toward the roller 46. Further, it flows into the first back pressure chamber 82 through the communication hole 110 formed in the intermediate partition plate 36 to urge the vane 52 toward the roller 48. On the other hand, the other refrigerant gas discharged into the discharge muffling chamber 62 is discharged outside through the refrigerant discharge pipe 96.
[0056]
Here, when the operation of the rotary compressor 10 is stopped, the discharge muffling chamber 62 and the second back pressure chamber 80 of the second rotary compression element 34 communicate with each other through the communication path 90, and the first rotary compression element 32 Since the first back pressure chamber 82 and the second back pressure chamber 80 of the second rotary compression element 34 communicate with each other through the communication hole 110, the vanes 50 and 52 are guided from these back pressure chambers 80 and 82. The high-pressure refrigerant gas in the cylinder 38 is bypassed to the cylinder 40 through the grooves 70 and 72 and the gaps between the springs 74 and 76 and the storage portions 70A and 72A. Thereby, the high-pressure refrigerant gas in the cylinder 38 reaches the equilibrium pressure in a short time.
[0057]
When the pressure in the discharge muffling chamber 62 decreases after the rotary compressor 10 stops and becomes lower than the pressure in the closed container 12, the pressure equalizing valve 101 is pushed downward by the pressure in the closed container 12 as described above, and The passage 100 is opened. As a result, the intermediate-pressure refrigerant gas in the sealed container 12 flows into the discharge muffling chamber 62.
[0058]
When the pressure in the discharge muffling chamber 62 increases due to the introduction of the pressure and the pressure in the discharge muffling chamber 62 becomes equal to the pressure in the closed container 12, the equalizing valve 101 closes the equalizing passage 100 as described above. On the other hand, since the discharge muffling chamber 62 and each of the back pressure chambers 80 and 82 communicate with each other through the communication passage 90 and the communication hole 110, the inside of the closed container 12, the discharge muffling chamber 62 and the back pressure chambers 80 and 82 are formed. , The pressure in each cylinder 40, 38 will quickly equilibrate. Therefore, the startability at the next restart is improved.
[0059]
As described above, the flammable refrigerant is used as the refrigerant, the refrigerant compressed by the first rotary compression element 32 is discharged into the closed container 12, and the discharged intermediate-pressure refrigerant is discharged by the second rotary compression element 34. In addition to the compression, the discharge muffling chamber 62 of the second rotary compression element 34 and the second back pressure chamber 80 communicate with each other through the communication passage 90, and further, the second back pressure chamber 80 and the first back pressure chamber 82 Are communicated through the communication hole 110 formed in the intermediate partition plate 36, so that the high-pressure refrigerant gas in the discharge muffling chamber 62 is added to the first and second back pressure chambers 80 and 82.
[0060]
As a result, even when the rotary compressor 10 of the internal intermediate pressure type is used, the vanes 50 and 52 are sufficiently urged toward the rollers 46 and 48, so that the first and second rotary compression elements such as vane skipping are generated. It becomes possible to avoid the unstable driving behavior of 32, 34.
[0061]
In particular, in the present invention, the inside pressure of the second rotary compression element 34 with respect to the excluded volume of the first rotary compression element 32 is set so that the pressure inside the closed container 12 is set to the intermediate pressure and the intermediate pressure inside the closed container 12 is reduced as described later. Since the ratio of the displacement volume is set to be large, the pressure in the sealed container 12 is increased when the rotary compressor 10 is started, but is discharged from the second rotary compression element 34 to the back pressure chambers 80 and 82. Since a very high pressure is applied, a sufficient back pressure is applied to the vane 52 from the start, and the reliability of the rotary compressor 10 can be improved.
[0062]
After the operation of the rotary compressor 10 is stopped, the inside of the discharge muffling chamber 62 and the second back pressure chamber 80 are communicated with each other through the communication path 90 as described above, and the second back pressure chamber 80 and the first back pressure chamber 80 are connected to each other. Is communicated with the back pressure chamber 82 through the communication hole 110, and the inside of the sealed container 12 and the inside of the discharge muffling chamber 62 are communicated with each other through the pressure equalizing passage 100, so that the inside of the rotary compressor 10 reaches an equilibrium pressure. Can be hastened.
[0063]
As a result, the differential pressure in the rotary compressor 10 can be eliminated in a short time, and the startability of the rotary compressor 10 can be significantly improved.
[0064]
In the embodiment, the multi-stage compression type rotary compressor 10 in which the rotary shaft 16 is installed vertically is described. However, it goes without saying that the present invention can be applied to a multi-stage compression type rotary compressor in which the rotary shaft is installed horizontally.
[0065]
Further, the multi-stage compression type rotary compressor has been described as a two-stage compression type rotary compressor having first and second rotary compression elements. However, the present invention is not limited to this, and three-stage, four-stage or more rotary compression elements may be used. It may be applied to a multi-stage compression type rotary compressor having components.
[0066]
【The invention's effect】
As described in detail above, according to the first aspect of the present invention, each of the first and second cylinders constituting the first and second rotary compression elements and the eccentric portion formed on the rotation shaft of the electric element are provided in each cylinder. First and second rollers respectively eccentrically rotating at each of the first and second rollers, first and second vanes abutting against each roller to partition the inside of each cylinder into a low-pressure chamber side and a high-pressure chamber side, respectively, First and second back pressure chambers for urging the refrigerant to the sides, using a flammable refrigerant as a refrigerant, discharging the refrigerant compressed by the first rotary compression element into a closed container, Since the intermediate pressure refrigerant is compressed by the second rotary compression element and the refrigerant discharge side of the second rotary compression element communicates with the first and second back pressure chambers, the first and second The high-pressure refrigerant compressed by the second rotary compression element is added to the back pressure chamber.
[0067]
As a result, the high-pressure refrigerant gas compressed by the second rotary compression element is added to the first and second back pressure chambers, so that the back pressure quickly rises from the start of the rotary compressor, and the vanes Unstable driving behavior such as jumping can be avoided. Thus, the reliability of the rotary compressor can be improved.
[0068]
According to the second aspect of the present invention, in addition to the above-mentioned invention, a support member for closing an opening surface of the second cylinder, and a discharge muffling device configured in the support member and discharging the refrigerant compressed in the second cylinder Chamber, a communication passage formed in the support member and communicating the discharge muffling chamber and the second back pressure chamber, an intermediate partition plate sandwiched between the first and second cylinders, and the intermediate partition plate And a communication hole that communicates the second back pressure chamber with the first back pressure chamber, so that the high pressure on the refrigerant discharge side of the second rotary compression element can be reduced by the simple structure with the first and second pressures. It can be applied to the second back pressure chamber. Thereby, workability is improved, and production costs can be reduced.
[0069]
According to a third aspect of the present invention, in addition to the second aspect of the present invention, there is provided a pressure equalizing passage for communicating the discharge muffling chamber with the inside of the closed container, and a pressure equalizing valve for opening and closing the pressure equalizing passage. Since the pressure equalizing passage is opened when the pressure in the discharge muffling chamber becomes lower than the pressure in the closed container, the pressure in the first rotary compression element, the second rotary compression element and the pressure in the closed container after the rotary compressor is stopped. Can be accelerated.
[0070]
This makes it possible to eliminate the high-low pressure difference in the rotary compressor in a short time, and to significantly improve the startability of the rotary compressor.
[0071]
Further, in the invention according to claim 4, a flammable refrigerant is used as the refrigerant, the refrigerant compressed by the first rotary compression element is discharged into the closed vessel, and the discharged intermediate-pressure refrigerant is subjected to the second rotary compression. When the pressure at the refrigerant discharge side of the second rotary compression element becomes lower than the pressure in the closed container, the refrigerant discharge side of the second rotary compression element communicates with the inside of the closed container. Since the pressure equalizing valve is provided, after the compressor is stopped, the pressures in the first rotary compression element, the second rotary compression element, and the closed container can be quickly balanced.
[0072]
This makes it possible to eliminate the high-low pressure difference in the rotary compressor in a short time, and to significantly improve the startability of the rotary compressor.
[0073]
According to a fifth aspect of the present invention, in addition to the fourth aspect, a cylinder constituting the second rotary compression element, a support member for closing an opening surface of the cylinder, and a support member formed in the support member and having a A discharge silence chamber from which the compressed refrigerant is discharged, a cover for partitioning the discharge silence chamber and the inside of the closed container, and a pressure equalizing passage formed in the cover, and a pressure equalizing valve is provided in the discharge silence chamber. Since it is provided and opens and closes the equalizing passage, productivity and space efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an internal intermediate pressure type multi-stage compression type rotary compressor according to an embodiment of the present invention.
FIG. 2 is an enlarged vertical sectional view of first and second rotary compression mechanisms of the internal intermediate pressure type multistage compression type rotary compressor of the present invention.
FIG. 3 is an enlarged vertical sectional view of a discharge muffling chamber of a second rotary compression element of the present invention.
FIG. 4 is a diagram showing the relationship between the suction pressure, the intermediate pressure and the high pressure with respect to the evaporation temperature in the internal intermediate pressure type multistage compression type rotary compressor of the present invention.
FIG. 5 is a diagram showing a relationship between suction pressure and high pressure with respect to evaporation temperature in a single cylinder rotary compressor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Multistage rotary compressor 12 Hermetic container 14 Electric element 16 Rotary shaft 18 Rotary compression mechanism 22 Stator 24 Rotor 26 Stack 28 Stack 28 Stator coil 30 Stack 32 First rotary compression element 34 Second rotary compression element 38, 40 Cylinder 54 Upper support member 56 Lower support members 62 and 64 Discharge muffling chamber 65 Cup 66 Upper cover 80 Second back pressure chamber 82 First back pressure chamber 90 Communication passage 100 Equalization passage 101 Equalization valve 110 Communication hole

Claims

An electric element, and first and second rotary compression elements driven by a rotary shaft of the electric element in a closed container, wherein the refrigerant compressed by the first rotary compression element is compressed by the second rotary compression element. In a multi-stage compression type rotary compressor that compresses
First and second cylinders constituting the first and second rotary compression elements, and first and second cylinders respectively eccentrically rotating in the respective cylinders by eccentric portions formed on the rotation shaft of the electric element. A roller, first and second vanes abutting on each roller to partition the inside of each cylinder into a low-pressure chamber side and a high-pressure chamber side, respectively, and a first vane for constantly urging each vane toward each of the rollers. And a second back pressure chamber,
Using a flammable refrigerant as the refrigerant, discharging the refrigerant compressed by the first rotary compression element into the closed container, compressing the discharged intermediate-pressure refrigerant with the second rotary compression element, A refrigerant discharge side of the second rotary compression element and the first and second back pressure chambers are communicated with each other.

A support member for closing an opening surface of the second cylinder;
A discharge muffling chamber configured in the support member and configured to discharge a refrigerant compressed in the second cylinder;
A communication passage formed in the support member and communicating the discharge muffling chamber and the second back pressure chamber;
An intermediate partition plate sandwiched between the first and second cylinders,
2. The multi-stage compression type rotary compressor according to claim 1, further comprising a communication hole formed in said intermediate partition plate and communicating with said second back pressure chamber and said first back pressure chamber.

A pressure equalizing passage that communicates the discharge muffling chamber and the inside of the closed container, and a pressure equalizing valve that opens and closes the pressure equalizing passage,
The multi-stage compression type rotary compressor according to claim 2, wherein the equalizing valve opens the equalizing passage when the pressure in the discharge muffling chamber becomes lower than the pressure in the closed container.

An electric element, and first and second rotary compression elements driven by a rotary shaft of the electric element in a closed container, wherein the refrigerant compressed by the first rotary compression element is compressed by the second rotary compression element. In a multi-stage compression type rotary compressor that compresses
Using a flammable refrigerant as the refrigerant, discharging the refrigerant compressed by the first rotary compression element into the closed container, compressing the discharged intermediate-pressure refrigerant with the second rotary compression element, When the pressure on the refrigerant discharge side of the second rotary compression element becomes lower than the pressure in the closed container, a pressure equalizing valve for communicating the refrigerant discharge side of the second rotary compression element with the closed container is provided. A multi-stage compression type rotary compressor comprising:

A cylinder constituting the second rotary compression element;
A support member for closing an opening surface of the cylinder,
A discharge muffling chamber configured in the support member and discharging a refrigerant compressed in the cylinder;
A cover for partitioning the discharge muffling chamber and the closed container,
A pressure equalizing passage formed in the cover,
The multistage compression type rotary compressor according to claim 4, wherein the equalizing valve is provided in the discharge muffling chamber and opens and closes the equalizing passage.