JP2004218941A

JP2004218941A - Cooling device

Info

Publication number: JP2004218941A
Application number: JP2003007168A
Authority: JP
Inventors: Shinya Koga; 愼弥古賀; Toshisuke Sakai; 敏輔酒井; Yasushi Niwatsukino; 恭庭月野; Toshiyuki Kubota; 俊幸久保田
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-01-15
Filing date: 2003-01-15
Publication date: 2004-08-05
Anticipated expiration: 2023-01-15
Also published as: JP3431024B1

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simply formed cooling device allowing reduction in size and thickness while improving cooling efficiency. <P>SOLUTION: In this cooling device, a radiator and a contact heat exchange type centrifugal pump are installed in a closed circulation passage for circulating refrigerant, the centrifugal pump is brought into contact with a heating electronic part 1 to remove heat from the heating electronic part by the heat exchange action of the refrigerant in the centrifugal pump for radiating heat from the radiator. The centrifugal pump comprises a pump casing 15 formed of a high heat conductive material and an open type impeller 11. A heat receiving surface 15b along a pump chamber 15a in the pump casing is formed in the pump casing 15 in such a shape in a contact state that is complemental to the three-dimensional shape of the upper surface of the heating electronic part 1. A suction passage 19 is installed between the heat receiving surface 15b and the inner wall surface of the pump chamber 15a. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、筐体内部に配設された中央処理装置（以下、ＣＰＵ）等の発熱電子部品を、冷媒を循環させて冷却する電子機器の冷却装置に関するものである。
【０００２】
【従来の技術】
最近のコンピューターにおける高速化の動きはきわめて急速であり、ＣＰＵのクロック周波数は以前と比較して格段に大きなものになってきている。この結果、ＣＰＵの発熱量が増し、従来のようにヒートシンクで空冷するだけでは能力不足で、高効率で高出力の冷却装置が不可欠になっている。そこでこのような冷却装置として、発熱電子部品を搭載した基板を、冷媒を循環させて冷却する冷却装置が提案された（特許文献１参照）。
【０００３】
以下、このような冷媒を循環させて冷却する従来の電子機器の冷却装置について説明する。なお、本明細書において電子機器というのは、ＣＰＵ等にプログラムをロードして処理を行う装置、中でもノート型パソコンのような携行可能な小型の装置を中核とするが、このほかに通電により発熱する発熱電子部品を搭載した装置を含むものである。この従来の第１の冷却装置は、例えば図１４に示すようなものが知られている。
【０００４】
図１４は従来の電子機器の第１冷却装置の構成図である。図１４において、１００は筐体であり、１０１は発熱電子部品、１０２は発熱電子部品１０１を実装した基板、１０３は発熱電子部品１０１と冷媒との間で熱交換を行ない発熱電子部品１０１を冷却する冷却器、１０４は冷媒から熱を取り除く放熱器、１０５は冷媒を循環させるポンプ、１０６はこれらを接続する配管、１０７は放熱器１０４を空冷するファンである。
【０００５】
この従来の第１冷却装置の動作を説明すると、ポンプ１０５から吐出された冷媒は、配管１０６を通って冷却器１０３に送られる。ここで発熱電子部品１０１の熱を奪うことでその温度が上昇し、放熱器１０４に送られる。この放熱器１０４でファン１０７によって強制空冷されてその温度が降下し、再びポンプ１０５へ戻ってこれを繰り返す。このように、冷媒を循環させて発熱電子部品１０１を冷却するものであった。
【０００６】
次に、電子機器の従来の第２冷却装置として、図１５に示すものが提案されている（特許文献１参照）。
【０００７】
この第２冷却装置は、発熱部材を狭い筐体内に搭載したとき、発熱部材の発生熱を放熱部である金属筐体壁まで効率良く輸送し発熱部材を冷却するものである。
【０００８】
図１５は従来の電子機器の第２冷却装置の構成図である。図１５において、１０８は電子機器の配線基板、１０９はキーボード、１１０は半導体発熱素子、１１１はディスク装置、１１２は表示装置、１１３は半導体発熱素子１１０との間で熱交換する受熱ヘッダ、１１４は放熱のための放熱ヘッダ、１１５はフレキシブルチューブ、１１６は電子機器の金属筐体である。
【０００９】
この第２冷却装置は、発熱部材である半導体発熱素子１１０と金属筐体１１６とをフレキシブル構造の熱輸送デバイスにより熱的に接続するものである。この熱輸送デバイスは、半導体発熱素子１１０に取り付けた液流路を有する扁平状の受熱ヘッダ１１３、液流路を有し金属筐体１１６の壁に接触させた放熱ヘッダ１１４、さらに両者を接続するフレキシブルチューブ１１５で構成され、内部に封入した液を放熱ヘッダ１１４に内蔵した液駆動機構により受熱ヘッダ１１３と放熱ヘッダ１１４との間で駆動あるいは循環させるものである。これにより、半導体発熱素子１１０と金属筐体１１６とが部品配列に左右されることなく容易に接続できるとともに、液の駆動により高効率で熱が輸送される。放熱ヘッダ１１４においては、放熱ヘッダ１１４と金属筐体１１６とが熱的に接続されているので、金属筐体１１６の高い熱伝導率のために熱が広く金属筐体１１６に拡散されるものである。
【００１０】
また、本出願人も、冷却効率を改善しながら小型化、薄型化でき、構造が簡単な渦流ポンプを使った冷却装置を既に提案した（特願２００２−１３９５９８）。
【００１１】
【特許文献１】
特開平７−１４２８８６号公報
【００１２】
【発明が解決しようとする課題】
しかしながら、従来の第１冷却装置では、発熱電子部品１０１と冷媒とで熱交換を行ない発熱電子部品１０１を冷却する冷却器１０３、冷媒から熱を取り除くための放熱器１０４、冷媒を循環させるポンプ１０５、図示はしないが冷媒を補充しなければならず補充用タンクが必要であり、これらを組み合わせるため装置が大型且つ複雑で小型化が難しく、コストも高くなるという問題があった。すなわち従来の第１冷却装置は、本来大型の電子機器の冷却に適したものであって、小型、軽量且つ薄型で、様々の姿勢で運ばれ、使われる最近の高性能携行型のノート型パソコン等には対応しきれないものであった。
【００１３】
また、従来の第２冷却装置はノート型パソコン等に使用することが可能であるが、半導体発熱素子１１０に取り付けた扁平状の受熱ヘッダ１１３も、金属筐体１１６の壁に接触させた放熱ヘッダ１１４もいずれもがボックス状で厚くならざるをえず、ノート型パソコン等の薄型化を妨げるものであった。すなわち従来の第２冷却装置では、放熱ヘッダ１１４の中に液体駆動装置として他のポンプより横幅が比較的小さくなる往復動ポンプが設けられており、残念なことに、この往復動ポンプが放熱ヘッダ１１４の厚さを規定して全体を厚くしている。これではノート型パソコンの薄型化はできない。
【００１４】
しかし、薄型のノート型パソコンで第２冷却装置の往復動ポンプを受熱ヘッダ１１３の中に収容することは困難である。すなわちポンプの厚さのほかに半導体発熱素子１１０等の厚みも加わって、ノート型パソコンの高さを増加させ、薄型化に逆行することになるからである。その上、往復動ポンプの振動と騒音は、これを載置する半導体発熱素子１１０に影響を与えるし、耳障りになる場合もあり、これらの面からも実現は困難である。
【００１５】
さらに、第２冷却装置において、金属筐体１１６の壁に接触させた放熱ヘッダ１１４は、放熱面積が小さくて伝熱効率が悪く、冷却力に限界が存在するものであった。冷却力を上げるために放熱面積を増すことも考えられるが、これ以上面積を増すのでは流路が長くなって循環量が増し、内蔵した往復動ポンプの出力増加を招き、これによって放熱ヘッダ１１４の厚みを増すという矛盾があった。そこで、往復動ポンプを独立して金属筐体１１６内に収納するという手段を講じると、限界まで無駄なスペースを減少させたノート型パソコン本体に新たなスペースを割かなければならないし、組み立て作業も面倒になってしまう。このように、第２冷却装置はノート型パソコン等の小型化、薄型化に対しては限界を有するものであった。そして、最近のようにＣＰＵの能力が向上して益々大きな冷却能力が要求されるときに、このような問題を抱えた従来の第２冷却装置では将来性で疑問が残るものであった。
【００１６】
また、従来の熱交換機能付ポンプは、冷媒を別の冷却水で冷やしているため、ポンプ内に冷却水路が必要で大型化しポンプ構造が複雑になり、また、冷却水を循環させる第２のポンプや冷却水から熱を奪う第２の熱交換器が必要であるため、システムが複雑で小型化が難しく、部品点数も作業性も悪く、従って熱効率も良好なものは見込めず、コストも高いという課題があった。
【００１７】
また、本出願人の提案した冷却装置は、従来の第１冷却装置、第２冷却装置の課題を解決できる優れた冷却装置であったが、渦流ポンプにおいては、ポンプ室がステータの外周側に位置するため、ＣＰＵの位置がポンプ中心に位置する場合には吸熱するポンプ室とＣＰＵとの距離が大きくなり、受熱効率の改善の余地があった。しかし、この渦流ポンプを単純に他の形式のポンプで置き換えることには困難があった。すなわち、他の形式のポンプでは吸込路と吐出路、さらにはステータが存在するため、ＣＰＵと接触する受熱面をポンプに構成することが難しいからである。そして、敢えてこれを実行しても小型化、薄型化することができなくなるものであった。
【００１８】
そこで、本発明は、冷却効率を改善しながら小型化、薄型化でき、構造が簡単な冷却装置を提供することを目的とする。
【００１９】
【課題を解決するための手段】
本発明の冷却装置は上記課題を解決するためになされたものであって、冷媒を循環するための閉循環路に放熱器と接触熱交換型の遠心ポンプが設けられ、遠心ポンプが発熱電子部品に接触されて内部の冷媒の熱交換作用で該発熱電子部品から熱を奪い、放熱器から放熱を行う冷却装置であって、遠心ポンプが、高熱伝導率の材料で構成されたポンプケーシングと開放型の羽根車とを備え、ポンプケーシングには、内部のポンプ室に沿った側面に受熱面が形成され、且つ該受熱面が接触位置において発熱電子部品の上部表面の３次元的な形状と相補的な形状に形成されとともに、受熱面とポンプ室の内壁面との間に吸込路が設けられたことを特徴とする。
【００２０】
本発明によれば、冷却効率を改善しながら小型化、薄型化でき、構造が簡単な冷却装置とすることができる。
【００２１】
【発明の実施の形態】
上記課題を解決するためになされた請求項１の発明は、冷媒を循環するための閉循環路に放熱器と接触熱交換型の遠心ポンプが設けられ、遠心ポンプが発熱電子部品に接触されて内部の冷媒の熱交換作用で該発熱電子部品から熱を奪い、放熱器から放熱を行う冷却装置であって、遠心ポンプが、高熱伝導率の材料で構成されたポンプケーシングと開放型の羽根車とを備え、ポンプケーシングには、内部のポンプ室に沿った側面に受熱面が形成され、且つ該受熱面が接触位置において発熱電子部品の上部表面の３次元的な形状と相補的な形状に形成されとともに、受熱面とポンプ室の内壁面との間に吸込路が設けられたことを特徴とする冷却装置であり、開放型の羽根車の羽根がポンプ室内部に形成される層流境界層を剥ぎ取るため乱流化して伝熱量が増し、吸込路が受熱面とポンプ室の内壁面との間に設けられているので、これによって吸込路近傍の受熱面の温度を下げることができ、吸込路が発熱電子部品の側に張り出していないので、受熱面に遠心ポンプの内部構成による形状の変化を形成する必要がなく、受熱面と発熱電子部品の上部表面が密着しているので、熱を効果的に受熱することができる。
【００２２】
請求項２の発明は、吸込路が、ポンプケーシングの肉厚方向に短軸をもつ楕円形状の断面を有していることを特徴とする請求項１記載の冷却装置であり、ポンプ室と発熱部品との距離を縮めることができるために、その間の熱抵抗を下げることができる。
【００２３】
請求項３の発明は、請求項１記載の冷却装置において、受熱面とポンプ室の内壁面との間に吸込路が設けられるのに代えて、羽根車の中心に吸水口が形成され、該吸水口と連通する吸込路が受熱面と対向するポンプケーシング側に設けられたことを特徴とする冷却装置であり、ポンプ室の受熱面と反対側から吸い込むことを可能とし、結果に、ポンプ室と発熱部品との距離を縮めることができるために、その間の熱抵抗を下げることができる。
【００２４】
請求項４の発明は、吸水口が、羽根車の軸中心と一致する軸中心を有していることを特徴とする請求項３記載の冷却装置であり、羽根車内の流れの対称性を保てるため流量を最も効率よく送ることができ、熱を効果的に受熱することができる。
【００２５】
請求項５の発明は、羽根車には、該羽根車の軸中心とずれた位置に貫通孔が形成されていることを特徴とする請求項１〜４のいずれかに記載の冷却装置であり、ポンプ室の羽根車背面から貫通孔を通って還流させることができ、羽根車中央に滞留し易い気泡やキャビティを排出し、キャビテーションによる騒音をなくし伝熱速度を向上できる。
【００２６】
請求項６の発明は、ポンプ室内壁面には、羽根の側面が回転する部分に動圧溝が設けられたことを特徴とする請求項１〜５のいずれかに記載の冷却装置であり、動圧溝が羽根車に円滑な回転をさせ、摩擦で発生する熱を抑え、受熱面の背面の表面積を増し、熱を効果的に受熱することができる。
【００２７】
請求項７の発明は、ポンプ室内壁には、羽根の側面がスライドする部分の少なくとも一部に層流境界層を剥離させる凹部が多数設けられていることを特徴とする請求項１〜６のいずれかに記載の冷却装置であり、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。
【００２８】
請求項８の発明は、ポンプ室内壁には、羽根の側面がスライドする部分の少なくとも一部に多数の突起体が設けられたことを特徴とする請求項１〜７のいずれかに記載の冷却装置であり、ポンプ室内の冷媒の乱流発生を促進し、伝熱を促進させることができる。
【００２９】
請求項９の発明は、ポンプ室内壁には、吸込路が対向するする部分の少なくとも一部に複数の突起体もしくは溝を設けたことを特徴とする請求項３記載の冷却装置であり、ポンプ室内の冷媒の乱流発生を促進し、伝熱面積を増加させることができるために伝熱を促進することができる。
【００３０】
請求項１０の発明は、羽根車には、羽根の入口側もしくは羽根間に攪拌用羽根車突起体が形成されていることを特徴とする請求項１〜９のいずれかに記載の冷却装置であり、攪拌用羽根車突起体が流路を攪拌するため、ポンプ室内の冷媒の乱流発生を促進する。
【００３１】
請求項１１の発明は、攪拌用羽根車突起体が、ポンプ室内壁に形成された突起体と半径方向でずれた位置に対向して設けられることを特徴とする請求項１０記載の冷却装置であり、攪拌用羽根車突起体が突起体と接触せずに流路を効果的に攪拌し、ポンプ室内の冷媒の乱流発生を促進し、伝熱面積も増加させ、伝熱効率を更に向上させることができる。
【００３２】
請求項１２の発明は、羽根の側面には、ポンプ室内壁の表面と接触する弾性線状体もしくは弾性板状体が設けられたことを特徴とする請求項１〜１１のいずれかに記載の冷却装置であり、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。
【００３３】
請求項１３の発明は、受熱面のポンプケーシング厚さが羽根車の軸中心を中心として半径方向に減少することを特徴とする請求項１〜１２のいずれかに記載の冷却装置であり、電子部品からの熱をポンプ室全体に拡散しやすくし、伝熱を促進させることができる。
【００３４】
請求項１４の発明は、冷媒の循環路と、前記循環路内の冷媒を循環させるポンプと、前記循環路内の冷媒の熱を放出する放熱器とを備えた電子部品の冷却装置であって、前記ポンプは、前記ポンプのハウジングと前記電子部品が熱的に接触するよう、前記電子部品に直接連結され、前記ポンプのポンプ室の中央部に吸水口が設けられたことを特徴とする電子部品の冷却装置であり、受熱面と発熱電子部品の上部表面が密着しており、ポンプ室の中央部から冷媒を吸い込むことを可能とし、温度の低い冷媒をポンプ室の中央部に供給することができ、羽根車内の流れの対称性を保てるため流量を最も効率よく送ることができ、熱を効果的に受熱することができる。
【００３５】
請求項１５の発明は、前記ポンプは遠心ポンプであることを特徴とする請求項１４記載の電子部品の冷却装置であり、開放型の羽根車の羽根がポンプ室内部に形成される層流境界層を剥ぎ取るため乱流化して伝熱量が増し、熱を効果的に受熱することができる。
【００３６】
請求項１６の発明は、前記ポンプのポンプ室内壁には、前記羽根車の側面がスライドする部分の少なくとも一部に層流境界層を剥離させる剥離手段がけられていることを特徴とする請求項１４記載の電子部品の冷却装置であり、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。
【００３７】
請求項１７の発明は、前記剥離手段が、少なくともポンプ室内壁には凹部または突起体が設けられていることを特徴とする請求項１４記載の電子部品の冷却装置であり、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。
【００３８】
請求項１８の発明は、前記剥離手段が、前記羽根車の側面に前記ポンプ室内壁の表面と接触する弾性線状体もしくは弾性板状体が設けられたことを特徴とする請求項１４記載の電子部品の冷却装置であり、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。
【００３９】
以下、本発明の実施の形態について、図１〜１３を用いて説明する。
【００４０】
（実施の形態１）
図１は本発明の実施の形態１における冷却装置の構成図、図２は本発明の実施の形態１における冷却装置を構成する熱交換型の遠心ポンプの構成図、図３は本発明の実施の形態１における遠心ポンプの羽根車正面図、図４は本発明の実施の形態１における遠心ポンプの流体軸受の展開図、図５は本発明の実施の形態１における遠心ポンプのポンプ室内壁面の外観図、図６（ａ）は本発明の実施の形態１における遠心ポンプの羽根車に取り付けたブラシの説明図、図６（ｂ）は本発明の実施の形態１における遠心ポンプの羽根車に取り付けたブレードの説明図、図７は図２の遠心ポンプのＸ−Ｘ断面図である。
【００４１】
図１において、１は冷却装置を構成する接触熱交換型の遠心ポンプ、２はＣＰＵ等の発熱電子部品であり、通常は表面がフラットなチップ部品である。なお、実施の形態１の遠心ポンプ１と発熱電子部品２は、きわめて小型で、ノート型パソコンのように携行可能な小型の電子機器に搭載されるものである。３は発熱電子部品２から受熱した冷媒を外部に放熱する放熱器、４は遠心ポンプ１と放熱器３を接続して冷媒を循環するための循環路である。なお、この冷媒としては、食品添加物などに用いられる無害なプロピレングリコール水溶液が適当であり、さらに後述するようにケーシング材料としてアルミや銅等を使用する場合には、これらに対する防食性能を向上させるための防食添加剤を添加するのが望ましい。
【００４２】
放熱器３は、熱伝導率が高く放熱性のよい材料、例えば銅、アルミニウム等の薄板材で構成され、内部に冷媒通路とリザーブタンクが形成されている。また、放熱器３に強制的に空気を当てて冷やし冷却効果を増やすためファンを設けてもよい。循環路４は、配管レイアウトの自由度を確保するため、フレキシブルでガス透過性の少ないゴム、例えばブチルゴムなどのゴムチューブで構成されている。これはチューブ内に気泡が混入するのを防止するためである。
【００４３】
次に、遠心ポンプ１の内部構成について説明する。図２〜図６（ａ），（ｂ）において、１１は遠心ポンプの開放型の羽根車、１１ａは羽根車１１に設けられた貫通孔、１２は羽根車１１の開放した羽根、１３は羽根車１１の外周側方に設けられたマグネットロータである。１４はマグネットロータ１３の内周側に設けられたステータ、１５は羽根車１１を収容すると同時に羽根車１１が流体に与えた運動エネルギーを圧力回復して吐出口へと導くポンプケーシング、１５ａは羽根１２で与えられた運動エネルギーを圧力回復して吐出口へと導くためのポンプ室、１５ｂはポンプ室１５ａに沿ったポンプケーシング１５の側面に形成され、発熱電子部品に接触して熱を奪う受熱面、１５ｃはポンプ室１５ａの内部のポンプ室内壁面、１６は羽根車１１を収納した後ポンプ室１５ｂを密閉するためのケーシングカバー、１７はポンプケーシング１５に設けられ、羽根車１１を回転自在に軸支するための固定軸、１８は羽根車１１の中心に設けられ固定軸１７に装着される軸受、１８ａは流体軸受の場合の動圧発生溝（図４参照）である。１９は吸込路、１９ａは吸水口、２０は吐出路である。２１はポンプ室内壁面１５ｃに形成された層流境界層を多数の凹部、２２は層流境界層を掻き取るブラシ（本発明の弾性線状体）、２２は層流境界層を掻き取るブレード（本発明の弾性板状体）である。
【００４４】
ケーシングカバー１６はポンプケーシング１５と組み立てられて全体として遠心ポンプ１のポンプケーシングを構成する。ポンプケーシング１５とケーシングカバー１６のうち少なくともポンプケーシング１５は、高熱伝導率で放熱性のよい材料、例えば銅、アルミニウム等で構成する。なお、本実施の形態１の遠心ポンプは回転軸方向の厚さが５〜１０ｍｍ、半径方向の代表寸法が４０〜５０ｍｍ、回転数は１２００ｒｐｍ、流量が０．０８〜０．１２Ｌ／分、ヘッドが０．３５〜０．４５ｍ程度のポンプである。そして、本発明のポンプの諸元は、本実施の形態１の値を含んで、厚さ３〜２０ｍｍ、半径方向代表寸法１０〜７０ｍｍ、流量が０．０１〜０．８Ｌ／分、ヘッド０．１〜２ｍ程度のものとなる。これは比速度でいうと、２４〜２８（単位：ｍ、ｍ^３／分、ｒｐｍ）程度のポンプであって、従来のポンプとはまったく隔絶した大きさの小型薄型のポンプである。
【００４５】
実施の形態１の遠心ポンプ１においては、羽根車１１の羽根１２と発熱電子部品２とが対向するように設置され、発熱電子部品２の上部表面と相補的な形状となる受熱面１５ｂが形成されており、受熱面１５ｂを介してポンプ室１５ａで直接受熱を行なう。ステータ１４はケーシングカバー１６に圧入され、マグネットロータ１３の内周面とステータ１４の外周部分が対向して配置される。
【００４６】
ステータ１４とマグネットロータ１３の間にはケーシングカバー１６が両者を仕切る分離板として配置され、ステータ１４は完全にポンプ室１５ａ内を流れる冷媒と隔離される。羽根車１１はマグネットロータ１３と別体構成でもよいが、実施の形態１においては一体で構成され、マグネットロータ１３となる円筒部に着磁させた一体型の羽根車１１としている。マグネットロータ１３がステータ１４の回転磁界の作用で回転することにより、羽根車１１が回転する。羽根車１１が回転すると、羽根車１１の中心付近に負圧が発生し、連通している吸込路１９から冷媒が吸い込まれ、羽根車１１によって運動量を得て外側に吐き出される。
羽根車１１の外周部分には吐出口（図示しない）が設けられ、吐出路２０を経て冷媒は循環路４に排出される。
【００４７】
羽根車１１の中心には低摩擦で耐磨耗性のセラミックからなる軸受１８が圧入され、さらにこれと同様に、その内側にはセラミックからなる固定軸１７がポンプケーシング１５とケーシングカバー１６に両端を固定されて配設される。図２に示すように、軸受１８の外周面にはＤカットを施し、羽根車１１の軸受圧入孔（図示しない）との間に隙間ができるように構成され、羽根車１１の背面側とポンプ室１５ａ側を連通している。この隙間が軸中心からずれた実施の形態１における貫通孔１１ａである。この貫通孔１１ａにより、羽根車１１で遠心力を受け押し出された冷媒の一部分は羽根車１１の背面側に回り込み、貫通孔１１ａを通って負圧状態の羽根車１１の吸水口１９ａに流出する。すなわち、遠心ポンプ１の中で一部の冷媒が還流している。還流する冷媒は吸水口１９ａ内で混合され、再度還流する冷媒は入れ替わったものとなる。
【００４８】
羽根車１１による遠心力で羽根車１１の中心付近は負圧となり、この付近はキャビテーションが発生し易い環境にある。しかし、実施の形態１の遠心ポンプ１は比速度で２４〜２８（単位：ｍ、ｍ^３／分、ｒｐｍ）程度であってキャビテーションは起こり難い上に、仮に発生しても上述した還流によって混合して排出されるものである。そして、発生したキャビティが羽根車１１の中央付近に留まろうとしても、羽根車１１の背面と吸水口１９ａ側で冷媒が入れ替わりながら循環するので、滞留することはない。また、冷却装置のどこかで空気が混入し、これが遠心ポンプ１に吸い込まれたとしても、還流によって羽根車１１の中央付近に滞留することがなく、気泡は徐々に排出される。従ってキャビテーションに原因する騒音は少なく、気層が形成されないし、流れが乱流化するため伝熱量も大きくなる。
【００４９】
また、図４に示すように軸受１８の代わりに流体軸受を用いてもよい。流体軸受の動圧発生溝１８ａをスパイラル形状として、循環を促進するようにすれば、気泡の排出性能を向上させることができる。動圧発生溝１８ａの形状としてはヘリングボーン形状などでもよい。羽根車１１の背面にも溝を形成し循環量と背圧を調整することもできる。これによって羽根車１１に対するアキシャル方向のスラストを発生することもできる。
【００５０】
さらに図５に示すように、ポンプ室内壁面１５ｃ（受熱面１５ｂの背面側）の羽根１２がスライドする部分の少なくとも一部に凹部２１を多数形成することにより、羽根車１１の回転で流動する冷媒がポンプ室内壁面１５ｃに沿って形成する層流境界層を剥離させ、乱流化することができる。これによって受熱面１５ｂから冷媒に伝達する熱量を大きくすることができる。同様に、ポンプ室内壁面１５ｃをショットピーニング加工、サンドブラスト加工などで凹凸を形成もしくは粗くすることにより、効果は多少低いが同様な原理で受熱効率を上げることが可能となる。さらに、図６に示すように、羽根１２だけでなく、ポンプ室内壁面１５ｃを軽く擦るようなブラシ２２や薄板状のブレード２３を羽根車に取り付けることにより、羽根車１１の回転力により強制的に層流境界層を崩し、受熱効率を向上させることができる。なお、図示はしないが、ポンプ室内壁面１５ｃにスパイラル形状の溝を形成しても、乱流化することで伝熱量を大きくすることができる。
【００５１】
発熱量に比べケーシングから冷媒への伝達係数が充分大きくとれ、大きな熱伝達量が得られる場合は、熱をポンプ室１５ａに沿って広げる必要がなくなるため、ポンプケーシング１５の受熱面１５ｂ部分の肉厚は薄い方が受熱効率がよくなり、ポンプを薄型にもできる。このために図７に示すように吸込路１９を肉厚方向に短軸をもつ楕円形状の断面とするのが好適である。羽根車１１の回転を障害しない範囲で伝熱面積を増やすために、ポンプ室内壁面１５ｃの羽根１２の側面がスライドする部分の少なくとも一部に小さな柱状体やリブ等の突起体を突出させ、伝熱面積が増加させるとともに乱流化を促進し、受熱量が増加させることができる。これらの柱状体やリブ等は、発熱電子部品２の中心を置く位置近傍に設けるのが受熱効率を増加する。そして発熱電子部品２の中心を羽根車１１の軸中心に配置させるときには、羽根車１１の軸中心付近に立設すればよい。
【００５２】
以上説明したように、実施の形態１の冷却装置の遠心ポンプ１には、高熱伝導率の材料で構成されたポンプケーシング１５と、羽根１２が形成された開放型の羽根車１１が設けられており、また、受熱面１５ｂと発熱電子部品２の上部表面の形状が３次元的に相補的形状とされ、且つ受熱面１５ｃとポンプ室内壁面１５ｃとの間（ポンプケーシング１５の肉厚部分）に肉厚方向に短軸をもつ楕円形状の吸込路１９が配設されているため、全体の肉厚も流路近傍の実質の肉厚も薄くすることができ、吸込路１９近傍の受熱面１５ｂの温度が下がり、吸込路１９が発熱電子部品２の側に張り出していないので、受熱面１５ｂに遠心ポンプ１の内部事情で形状変化を加える必要がなく、受熱面１５ｂと発熱電子部品２の上部表面が密着できるため、効果的に受熱できる。
【００５３】
（実施の形態２）
実施の形態２の遠心ポンプは、吸水口が羽根車の背面側に設置されたことを特徴とするものである。図８は本発明の実施の形態２における冷却装置を構成する熱交換型の遠心ポンプの構成図、図９は本発明の実施の形態２における遠心ポンプの羽根車の正面図、図１０は本発明の実施の形態２における遠心ポンプが回転短軸を備えた羽根車の構成図、図１１は本発明の実施の形態２における遠心ポンプのポンプ室内壁面の正面図、図１２は本発明の実施の形態２における遠心ポンプのポンプケーシング厚さが半径方向に減少する構成図である。なお、実施の形態２の遠心ポンプは実施の形態１の遠心ポンプと同一の構成部分を有しているため、同一符号の説明は省略する。
【００５４】
図８において、１９ｂは吸込路１９とつながった吸水口であり、羽根車１１の中心近傍に設けられ、背面側とポンプ室１５ａ側とを貫通するものである。この吸水口１９ｂは、図９に示すように半径方向の同位置にずれて設けられた３個の貫通孔から構成される。吸込路１９はケーシングカバー１６のステータ１４の中央に設けられており、吸水口１９ｂと連通する。固定軸１７、軸受１８は実施の形態１と同様に配置される。
【００５５】
このように、吸込路１９を受熱面１５ｂと反対側に配置したことにより、ポンプケーシング１５の受熱面１５ｂ側の肉厚を薄くすることができ、発熱量に比べケーシングから冷媒への伝達係数が充分大きくとれ、大きな熱伝達量が得られる場合は、熱をポンプ室１５ａに沿って広げる必要がなく、受熱効率を増すことができる。また、羽根車１１の中心近くに吸水口１９ｂを設けることにより、羽根車１１の背面から冷媒を吸い込むことができる。
【００５６】
なお、図１０（ａ），（ｂ）に示すように、固定軸を取り除いて、羽根車１１の背面から冷媒を吸い込む構成としてもよい。図１０（ａ）において、１６ａはケーシングカバー、１６ｂはケーシングカバー１６ａの中央に設けられ吸込路１９が内部に設けられる筒部、１７ａは羽根車１１の中央に設けられた回転短軸、１８ｂは筒部１６ｂに設けられ回転短軸１７ａが挿入されて軸支する軸受、１９ｃは羽根車１１の軸中心に形成された貫通孔からなる吸水口である。２４は吸水口１９ｃと対向するポンプ室内壁面１５ｃ中央に設けられた柱状体やリブ等の突起体である。なお、実施の形態２の場合、突起体２４は円柱である。また図１０（ｂ）において、１１ｃは羽根１２の入口側もしくは羽根１２間に設けられた根車突起体である。
【００５７】
このように吸水口１９ｃによって、背面側の吸込路１９とポンプ室１５ａを連通させ、羽根車１１の背面側からの吸込みが可能となる。発熱電子部品２と反対側からの吸い込みにより、受熱面１５ｂのポンプ室壁面１５ｃに冷媒を直接噴射する噴流効果も加わって、高効率の受熱が可能となる。
【００５８】
また、ポンプ室内壁面１５ｃから突起体２４が突出されることにより、受熱面積が増加し、受熱量を大幅に向上させることができる。また突起体２４により、ポンプ室内壁面１５ｃで乱流を発生させ、受熱効率を向上させることができる。
羽根車１１の中央部分には羽根１２が存在しないため、この部分に突起体２４を設けるのが容易であり、とくに発熱電子部品２の中心が設置バランス上、羽根車１１の中央に位置することが多いので、この部分に突起体２４を設けることにより局所的に受熱効率を向上させることができる。すなわち、羽根車１１の中央で吸水するため、この位置に突起体２４を設けることは、発熱電子部品２の熱が一番高く冷媒との温度差を最も大きいため、伝熱量が大きくなる。また、この部分で突起体２４を設けることにより伝熱面積を増加させるため、熱抵抗を減少させることができ熱量の移動を促進できる。さらに、噴流効果による受熱効率向上が望めるものである。そして突起体２４で乱流が発生し、これによる受熱効率向上もアップする。なお、突起体２４に代えて溝を形成するのでも、同様の作用効果が期待できる。
【００５９】
さらに、図１０（ｂ）に示すように、ポンプ室１５ａの羽根１２の入口側に突起体２４を設け、この突起体２４と半径方向にみていわば噛み合うような配置で攪拌用羽根車突起体１１ｃを設けるのが好適である。望ましくは攪拌用羽根車突起体１１ｃを螺旋状に配置させるのがよい。接触を避けるため、突起体２４は攪拌用羽根車突起体１１ｃと同心円上に位置しないように、半径方向にずれた位置で対向して設ける必要がある。攪拌用羽根車突起体１１ｃと突起体２４の攪拌作用によって羽根１２の入口側で乱流化が促進され、また突起体２４の存在で放熱面積が増していることもあり、受熱効率がきわめて向上する。実験によれば、３０００ｒｐｍで、この構成による熱伝導率は６０００Ｗ／ｍ^２Ｋ近傍を示し、受熱面１５ｂから冷媒に最大の熱量を放熱することができる。
【００６０】
また、発熱電子部品２の接触面積が羽根１２の回転面積より小さく、受熱した熱をポンプ室１５ａに沿った側面に広げる必要がある場合には、薄い肉厚のポンプケーシングより、図１２に示すように中心部が盛り上がったポンプ室内壁面１５ｃが受熱効率の向上には貢献する。図１２において、１５ｄはポンプケーシング１５の肉厚が羽根車１１の軸中心を中心として半径方向に減少するように構成したポンプ室内壁面である。熱流束は通過する断面積が大きかったり、熱伝導率が大きいなどといった熱抵抗が小さい部分を流れ易く、肉厚が半径方向に減少するポンプ室内壁面１５ｄとすることにより、熱をポンプ室１５ａに沿った側面にまで広げることができる。
【００６１】
ところで、図１０で示した遠心ポンプの構成においては、マグネットロータ１３の周方向内周面と外周面、羽根車１１の表面にへリングボーン形状等の溝を形成して羽根車１１を流体の動圧で保持するとともに、ケーシングカバー１６ａの筒部１６ｂの軸受１８ｂと羽根車１１の中央に設けられた回転短軸１７ａとの間で軸支するから、簡単な構成で羽根車１１の安定した円滑な回転を確保し、伝熱を促進させることができる。
【００６２】
（実施の形態３）
実施の形態３の遠心ポンプは、羽根車１１を円盤状とし、羽根車１１に着磁したものである。図１３は本発明の実施の形態３における冷却装置を構成する熱交換型の遠心ポンプの構成図である。図１３において、１１ｂは羽根車１１の背面に着磁されて設けられたマグネットである。マグネット１１ｂは、別体の平板状の磁石を羽根車に取り付けることで形成するのでもよい。さらに実施の形態１，２と同様に、受熱効率を向上させうるために、ポンプ室壁面１５ｃに凹部や柱状体、羽根車１１にブラシ、ブレードを設けたり、中心部の肉厚を増したりもできる。
【００６３】
このように実施の形態３の遠心ポンプ１は、軸方向の厚さを薄型にすることができ、ノート型パソコンのように携行可能な小型の電子機器に搭載することにより、発熱電子機器２の冷却を効果的に行うことができる。
【００６４】
【発明の効果】
本発明の冷却装置によれば、開放型の羽根車の羽根がポンプ室内部に形成される層流境界層を剥ぎ取るため乱流化して伝熱量が増し、吸込路が受熱面とポンプ室の内壁面との間に設けられているので、これによって吸込路近傍の受熱面の温度を下げることができ、吸込路が発熱電子部品の側に張り出していないので、受熱面に遠心ポンプの内部構成による形状の変化を形成する必要がなく、受熱面と発熱電子部品の上部表面が密着しているので、熱を効果的に受熱することができる。
【００６５】
肉厚方向に短軸をもつ楕円形状の断面を有してため、ポンプ室と発熱部品との距離を縮めることができるために、その間の熱抵抗を下げることができる。
【００６６】
吸水口と連通する吸込路が受熱面と対向するポンプケーシング側に設けられたため、ポンプ室の受熱面と反対側から吸い込むことを可能とし、結果に、ポンプ室と発熱部品との距離を縮めることができるために、その間の熱抵抗を下げることができる。
【００６７】
吸水口が、羽根車の軸中心と一致する軸中心を有してから、羽根車内の流れの対称性を保てるため流量を最も効率よく送ることができ、熱を効果的に受熱することができる。
【００６８】
羽根車の軸中心とずれた位置に貫通孔が形成されているから、ポンプ室の羽根車背面から貫通孔を通って還流させることができ、羽根車中央に滞留し易い気泡やキャビティを排出し、キャビテーションによる騒音をなくし伝熱速度を向上できる。
【００６９】
ポンプ室内壁面には、羽根の側面が回転する部分を含んで動圧溝が設けられているから、動圧溝が羽根車に円滑な回転をさせ、摩擦で発生する熱を抑え、受熱面の背面の表面積を増し、熱を効果的に受熱することができる。羽根の側面がスライドする部分の少なくとも一部に層流境界層を剥離させる凹部が多数設けられているから、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。羽根の側面がスライドする部分の少なくとも一部に多数の突起体が設けられたため、ポンプ室内の冷媒の乱流発生を促進し、伝熱を促進させることができる。羽根の側面がスライドする部分の少なくとも一部に複数の突起体もしくは溝を設けたから、ポンプ室内の冷媒の乱流発生を促進し、伝熱面積を増加させることができるために伝熱を促進することができる。
【００７０】
羽根の入口側もしくは羽根間に攪拌用羽根車突起体が形成され、攪拌用羽根車突起体が流路を攪拌するため、ポンプ室内の冷媒の乱流発生を促進することができる。また、攪拌用羽根車突起体が、ポンプ室内壁に形成された突起体と半径方向でずれた位置に対向して設けられるため、攪拌用羽根車突起体が突起体と接触せずに流路を効果的に攪拌し、ポンプ室内の冷媒の乱流発生を促進し、伝熱面積も増加させ、伝熱効率を更に向上させることができる。
【００７１】
羽根の側面には、ポンプ室内壁の表面と接触する弾性線状体もしくは弾性板状体が設けられたため、伝熱量が小さい層流境界層を剥離させ、乱流境界層として伝熱を促進させることができる。ポンプケーシング厚さが羽根車の軸中心を中心として半径方向に減少するため、電子部品からの熱をポンプ室全体に拡散しやすくし、伝熱を促進させることができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１における冷却装置の構成図
【図２】本発明の実施の形態１における冷却装置を構成する熱交換型の遠心ポンプの構成図
【図３】本発明の実施の形態１における遠心ポンプの羽根車正面図
【図４】本発明の実施の形態１における遠心ポンプの流体軸受の展開図
【図５】本発明の実施の形態１における遠心ポンプのポンプ室内壁面の外観図
【図６】（ａ）本発明の実施の形態１における遠心ポンプの羽根車に取り付けたブラシの説明図
（ｂ）本発明の実施の形態１における遠心ポンプの羽根車に取り付けたブレードの説明図
【図７】図２の遠心ポンプのＸ−Ｘ断面図
【図８】本発明の実施の形態２における冷却装置を構成する熱交換型の遠心ポンプの構成図
【図９】本発明の実施の形態２における遠心ポンプの羽根車の正面図
【図１０】本発明の実施の形態２における遠心ポンプが回転短軸を備えた羽根車の構成図
【図１１】本発明の実施の形態２における遠心ポンプのポンプ室内壁面の正面図
【図１２】本発明の実施の形態２における遠心ポンプのポンプケーシング厚さが半径方向に減少する構成図
【図１３】本発明の実施の形態３における冷却装置を構成する熱交換型の遠心ポンプの構成図
【図１４】従来の電子機器の第１冷却装置の構成図
【図１５】従来の電子機器の第２冷却装置の構成図
【符号の説明】
１遠心ポンプ
２発熱電子部品
３放熱器
４循環路
１１羽根車
１１ａ貫通孔
１１ｂマグネット
１１ｃ攪拌用羽根車突起体
１２羽根
１３マグネットロータ
１４ステータ
１５ポンプケーシング
１５ａポンプ室
１５ｂ受熱面
１５ｃ，１５ｄポンプ室内壁面
１６，１６ａケーシングカバー
１６ｂ筒部
１７固定軸
１７ａ回転短軸
１８，１８ｂ軸受
１８ａ動圧発生溝
１９吸込路
１９ａ，１９ｂ，１９ｃ吸水口
２０吐出路
２１凹部
２２ブラシ
２３ブレード
２４突起体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cooling device for an electronic device that cools a heat-generating electronic component such as a central processing unit (hereinafter, a CPU) disposed inside a housing by circulating a coolant.
[0002]
[Prior art]
In recent years, the speed at which computers have become faster is extremely rapid, and the clock frequency of CPUs has become much higher than before. As a result, the amount of heat generated by the CPU is increased, and the air-cooling with a heat sink as in the related art is insufficient in capacity, and a high-efficiency, high-output cooling device is indispensable. Therefore, as such a cooling device, a cooling device that circulates a cooling medium to cool a substrate on which heat-generating electronic components are mounted has been proposed (see Patent Document 1).
[0003]
Hereinafter, a cooling device for a conventional electronic device that circulates and cools such a refrigerant will be described. In this specification, an electronic device is a device that loads a program into a CPU or the like to perform processing, and in particular, is a small portable device such as a notebook computer. Including a device on which heat-generating electronic components are mounted. As this conventional first cooling device, for example, the one shown in FIG. 14 is known.
[0004]
FIG. 14 is a configuration diagram of a first cooling device of a conventional electronic device. 14, reference numeral 100 denotes a housing; 101, a heat-generating electronic component; 102, a board on which the heat-generating electronic component 101 is mounted; 103, a heat exchange between the heat-generating electronic component 101 and a refrigerant to cool the heat-generating electronic component 101; A radiator 104 for removing heat from the refrigerant, a pump 105 for circulating the refrigerant, a pipe 106 for connecting these, and a fan 107 for cooling the radiator 104 by air.
[0005]
Explaining the operation of this conventional first cooling device, the refrigerant discharged from the pump 105 is sent to the cooler 103 through the pipe 106. Here, by removing the heat of the heat-generating electronic component 101, its temperature rises and is sent to the radiator 104. The radiator 104 is forcibly air-cooled by the fan 107 to lower its temperature, and returns to the pump 105 again to repeat this. In this way, the heat-generating electronic component 101 is cooled by circulating the refrigerant.
[0006]
Next, as a conventional second cooling device for electronic equipment, the one shown in FIG. 15 has been proposed (see Patent Document 1).
[0007]
In the second cooling device, when the heat-generating member is mounted in a narrow housing, heat generated by the heat-generating member is efficiently transported to the metal housing wall, which is a heat radiating portion, to cool the heat-generating member.
[0008]
FIG. 15 is a configuration diagram of a second cooling device of a conventional electronic device. 15, reference numeral 108 denotes a wiring board of an electronic device, 109 denotes a keyboard, 110 denotes a semiconductor heating element, 111 denotes a disk device, 112 denotes a display device, 113 denotes a heat receiving header for exchanging heat with the semiconductor heating element 110, and 114 denotes a heat receiving header. A heat dissipation header for heat dissipation, 115 is a flexible tube, and 116 is a metal housing of an electronic device.
[0009]
The second cooling device thermally connects the semiconductor heat generating element 110, which is a heat generating member, and the metal housing 116 by a heat transport device having a flexible structure. In this heat transport device, a flat heat receiving header 113 having a liquid flow path attached to a semiconductor heating element 110, a heat radiation header 114 having a liquid flow path and in contact with a wall of a metal housing 116, and further connect the two. It is configured by a flexible tube 115 and drives or circulates the liquid sealed therein between the heat receiving header 113 and the heat radiation header 114 by a liquid drive mechanism built in the heat radiation header 114. Thereby, the semiconductor heating element 110 and the metal housing 116 can be easily connected without being affected by the arrangement of parts, and heat is transported with high efficiency by driving the liquid. In the heat dissipation header 114, since the heat dissipation header 114 and the metal housing 116 are thermally connected, heat is widely diffused to the metal housing 116 due to the high thermal conductivity of the metal housing 116. is there.
[0010]
In addition, the present applicant has already proposed a cooling device using a vortex pump having a simple structure that can be reduced in size and thickness while improving the cooling efficiency (Japanese Patent Application No. 2002-139598).
[0011]
[Patent Document 1]
JP-A-7-142886
[0012]
[Problems to be solved by the invention]
However, in the first conventional cooling device, a heat exchange is performed between the heat-generating electronic component 101 and the refrigerant to cool the heat-generating electronic component 101, a radiator 104 for removing heat from the refrigerant, and a pump 105 for circulating the refrigerant. Although not shown, the refrigerant must be replenished and a replenishing tank is required, and there is a problem that the combination of these tanks makes the apparatus large, complicated, difficult to miniaturize, and increases the cost. That is, the conventional first cooling device is originally suitable for cooling a large-sized electronic device, and is a recent high-performance portable notebook personal computer which is small, light and thin, and is carried and used in various postures. And so on.
[0013]
Further, the conventional second cooling device can be used for a notebook computer or the like, but the flat heat receiving header 113 attached to the semiconductor heating element 110 is also a heat dissipation header contacting the wall of the metal housing 116. Each of the 114 was inevitably thick in the shape of a box, which hindered the thinning of a notebook computer or the like. That is, in the second conventional cooling device, a reciprocating pump whose width is relatively smaller than that of the other pumps is provided as a liquid driving device in the heat dissipation header 114. The thickness of 114 is specified to make the whole thicker. This does not make the notebook PC thinner.
[0014]
However, it is difficult to accommodate the reciprocating pump of the second cooling device in the heat receiving header 113 with a thin notebook personal computer. That is, in addition to the thickness of the pump, the thickness of the semiconductor heating element 110 and the like are added, so that the height of the notebook personal computer is increased, which is against the thinner type. In addition, the vibration and noise of the reciprocating pump affect the semiconductor heat generating element 110 on which the pump is mounted, and may be unpleasant.
[0015]
Further, in the second cooling device, the heat dissipation header 114 that is in contact with the wall of the metal housing 116 has a small heat dissipation area, has poor heat transfer efficiency, and has a limit in cooling power. It is conceivable to increase the heat radiation area in order to increase the cooling power. However, if the heat radiation area is further increased, the flow path becomes longer and the amount of circulation increases, thereby increasing the output of the built-in reciprocating pump. There was a contradiction to increase the thickness of the. Therefore, if measures are taken to house the reciprocating pump independently in the metal casing 116, it is necessary to devote a new space to the notebook personal computer body, which has reduced wasteful space to the limit, and the assembling work is also required. It will be troublesome. As described above, the second cooling device has a limit in reducing the size and thickness of a notebook computer or the like. In recent years, when the performance of the CPU has been improved and a larger cooling capacity is required, the conventional second cooling device having such a problem has a problem in the future.
[0016]
Further, since the conventional pump with a heat exchange function cools the refrigerant with another cooling water, a cooling water passage is required in the pump, the pump becomes large and the pump structure becomes complicated, and the second pump for circulating the cooling water is used. Since a second heat exchanger for removing heat from the pump and cooling water is required, the system is complicated and difficult to miniaturize, and the number of parts and workability are poor, so that one with good thermal efficiency cannot be expected and the cost is high. There was a problem.
[0017]
Further, the cooling device proposed by the present applicant is an excellent cooling device that can solve the problems of the conventional first cooling device and second cooling device. However, in the vortex pump, the pump chamber is located on the outer peripheral side of the stator. Therefore, when the position of the CPU is located at the center of the pump, the distance between the pump chamber that absorbs heat and the CPU increases, and there is room for improvement in heat receiving efficiency. However, it has been difficult to simply replace this vortex pump with another type of pump. That is, in other types of pumps, the suction path, the discharge path, and the stator are present, so that it is difficult to configure the heat receiving surface in contact with the CPU in the pump. And even if this is performed dare, it is impossible to reduce the size and thickness.
[0018]
Accordingly, an object of the present invention is to provide a cooling device that can be reduced in size and thickness while improving the cooling efficiency and has a simple structure.
[0019]
[Means for Solving the Problems]
The cooling device of the present invention has been made in order to solve the above-described problems, and a radiator and a contact heat exchange type centrifugal pump are provided in a closed circulation path for circulating a refrigerant, and the centrifugal pump is a heat-generating electronic component. A cooling device that removes heat from the heat-generating electronic components by a heat exchange action of an internal refrigerant by contacting with the inside, and radiates heat from a radiator, wherein a centrifugal pump is opened with a pump casing made of a material having a high thermal conductivity. The pump casing has a heat receiving surface formed on a side surface along an internal pump chamber, and the heat receiving surface is complementary to a three-dimensional shape of an upper surface of the heat-generating electronic component at a contact position. And a suction path is provided between the heat receiving surface and the inner wall surface of the pump chamber.
[0020]
ADVANTAGE OF THE INVENTION According to this invention, a cooling apparatus which can be reduced in size and thickness while improving cooling efficiency, and which has a simple structure can be provided.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a radiator and a contact heat exchange type centrifugal pump are provided in a closed circuit for circulating a refrigerant, and the centrifugal pump is brought into contact with a heat-generating electronic component. A cooling device that removes heat from the heat-generating electronic components by a heat exchange action of an internal refrigerant and radiates heat from a radiator, wherein a centrifugal pump includes a pump casing made of a material having high thermal conductivity and an open impeller. A heat receiving surface is formed on a side surface of the pump casing along the inner pump chamber, and the heat receiving surface has a shape complementary to the three-dimensional shape of the upper surface of the heat-generating electronic component at the contact position. A cooling device, wherein a suction passage is provided between a heat receiving surface and an inner wall surface of a pump chamber, wherein a laminar flow boundary in which an open impeller blade is formed inside a pump chamber. Turbulence to peel off layers The amount of heat increases, and the suction passage is provided between the heat receiving surface and the inner wall surface of the pump chamber, so that the temperature of the heat receiving surface near the suction passage can be reduced, and the suction passage is located on the side of the heat-generating electronic components. Since it does not overhang, there is no need to form a shape change due to the internal configuration of the centrifugal pump on the heat receiving surface, and the heat receiving surface and the upper surface of the heat-generating electronic component are in close contact, so that heat can be effectively received. .
[0022]
The invention according to claim 2 is the cooling device according to claim 1, wherein the suction passage has an elliptical cross section having a short axis in a thickness direction of the pump casing. Since the distance to the component can be shortened, the thermal resistance therebetween can be reduced.
[0023]
According to a third aspect of the present invention, in the cooling device according to the first aspect, instead of providing the suction passage between the heat receiving surface and the inner wall surface of the pump chamber, a water suction port is formed at the center of the impeller. A cooling device characterized in that a suction passage communicating with a water suction port is provided on a pump casing side facing a heat receiving surface, and allows suction from a side of the pump chamber opposite to the heat receiving surface. Since the distance between the heat generating component and the heat generating component can be reduced, the thermal resistance therebetween can be reduced.
[0024]
According to a fourth aspect of the present invention, there is provided the cooling device according to the third aspect, wherein the water inlet has an axial center coinciding with the axial center of the impeller, and the symmetry of the flow in the impeller can be maintained. Therefore, the flow rate can be sent most efficiently, and the heat can be effectively received.
[0025]
The invention according to claim 5 is the cooling device according to any one of claims 1 to 4, wherein the impeller is formed with a through hole at a position shifted from the axial center of the impeller. In addition, it is possible to recirculate through the through hole from the back of the impeller of the pump chamber, to discharge air bubbles and cavities that easily stay at the center of the impeller, to eliminate noise due to cavitation, and to improve the heat transfer speed.
[0026]
The invention according to claim 6 is the cooling device according to any one of claims 1 to 5, wherein a dynamic pressure groove is provided on a portion of the pump chamber wall surface where the side surface of the blade rotates. The pressure grooves cause the impeller to rotate smoothly, suppress heat generated by friction, increase the surface area on the back surface of the heat receiving surface, and receive heat effectively.
[0027]
The invention according to claim 7 is characterized in that at least a part of the portion where the side surface of the blade slides is provided with a large number of concave portions for separating the laminar flow boundary layer on the inner wall of the pump. The cooling device according to any of the above, wherein the laminar boundary layer having a small heat transfer amount is separated, and heat transfer can be promoted as a turbulent boundary layer.
[0028]
The invention according to claim 8 is the cooling device according to any one of claims 1 to 7, wherein a large number of protrusions are provided on at least a part of a portion where the side surface of the blade slides on the inner wall of the pump. The device is capable of promoting generation of turbulent flow of the refrigerant in the pump chamber and promoting heat transfer.
[0029]
According to a ninth aspect of the present invention, in the cooling device according to the third aspect, a plurality of protrusions or grooves are provided on at least a part of a portion of the pump chamber wall facing the suction passage. Since the generation of turbulent flow of the indoor refrigerant can be promoted and the heat transfer area can be increased, heat transfer can be promoted.
[0030]
The invention according to claim 10 is the cooling device according to any one of claims 1 to 9, wherein the impeller is formed with a stirring impeller protrusion on the inlet side of the blade or between the blades. In addition, since the stirring impeller protrusion stirs the flow path, the generation of turbulent flow of the refrigerant in the pump chamber is promoted.
[0031]
The invention according to claim 11 is the cooling device according to claim 10, wherein the stirring impeller protrusion is provided at a position radially shifted from a protrusion formed on the inner wall of the pump chamber. Yes, the stirring impeller protrusion effectively stirs the flow path without contacting the protrusion, promotes the generation of turbulence of the refrigerant in the pump chamber, increases the heat transfer area, and further improves the heat transfer efficiency. be able to.
[0032]
According to a twelfth aspect of the present invention, in the first aspect, an elastic linear body or an elastic plate-like body that is in contact with the surface of the inner wall of the pump chamber is provided on a side surface of the blade. It is a cooling device that can separate a laminar boundary layer having a small amount of heat transfer and promote heat transfer as a turbulent boundary layer.
[0033]
The invention according to claim 13 is the cooling device according to any one of claims 1 to 12, wherein the thickness of the pump casing on the heat receiving surface decreases in a radial direction about the axial center of the impeller. The heat from the parts can be easily diffused throughout the pump chamber, and the heat transfer can be promoted.
[0034]
An invention according to claim 14 is a cooling device for an electronic component, comprising: a circulation path of a refrigerant; a pump that circulates the refrigerant in the circulation path; and a radiator that releases heat of the refrigerant in the circulation path. Wherein the pump is directly connected to the electronic component such that a housing of the pump and the electronic component are in thermal contact with each other, and a water inlet is provided at a central portion of a pump chamber of the pump. A cooling device for components, where the heat receiving surface and the upper surface of the heat-generating electronic components are in close contact, allowing refrigerant to be sucked in from the center of the pump chamber, and supplying low-temperature refrigerant to the center of the pump chamber. In order to maintain the symmetry of the flow in the impeller, the flow rate can be sent most efficiently, and the heat can be effectively received.
[0035]
The invention according to claim 15 is the cooling device for an electronic component according to claim 14, wherein the pump is a centrifugal pump, wherein a laminar flow boundary in which the blade of the open impeller is formed inside the pump chamber. Since the layer is stripped, the layer becomes turbulent and the amount of heat transfer increases, so that heat can be effectively received.
[0036]
The invention according to claim 16 is characterized in that at least a part of the part where the side surface of the impeller slides is provided with a separating means for separating the laminar boundary layer on the inner wall of the pump. 15. The cooling device for an electronic component according to 14, wherein the laminar boundary layer having a small heat transfer amount is separated, and the heat transfer can be promoted as a turbulent boundary layer.
[0037]
The invention according to claim 17 is the cooling device for an electronic component according to claim 14, wherein the peeling means is provided with a concave portion or a protrusion at least on the inner wall of the pump chamber. The flow boundary layer can be separated, and heat transfer can be promoted as a turbulent boundary layer.
[0038]
The invention according to claim 18 is characterized in that the peeling means is provided with an elastic linear body or an elastic plate-like body which is in contact with a surface of the inner wall of the pump chamber on a side surface of the impeller. It is a cooling device for an electronic component, which can separate a laminar boundary layer having a small heat transfer amount and promote heat transfer as a turbulent boundary layer.
[0039]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0040]
(Embodiment 1)
FIG. 1 is a configuration diagram of a cooling device according to Embodiment 1 of the present invention, FIG. 2 is a configuration diagram of a heat exchange type centrifugal pump that configures a cooling device according to Embodiment 1 of the present invention, and FIG. Fig. 4 is a front view of an impeller of a centrifugal pump according to Embodiment 1 of the present invention. Fig. 4 is a development view of a fluid bearing of the centrifugal pump according to Embodiment 1 of the present invention. FIG. 6A is an explanatory view of a brush attached to the impeller of the centrifugal pump according to the first embodiment of the present invention, and FIG. 6B is a diagram illustrating the impeller of the centrifugal pump according to the first embodiment of the present invention. FIG. 7 is a cross-sectional view of the centrifugal pump of FIG.
[0041]
In FIG. 1, reference numeral 1 denotes a contact heat exchange type centrifugal pump constituting a cooling device, and 2 denotes a heat-generating electronic component such as a CPU, which is usually a chip component having a flat surface. The centrifugal pump 1 and the heat-generating electronic component 2 according to the first embodiment are extremely small, and are mounted on a small-sized portable electronic device such as a notebook computer. Reference numeral 3 denotes a radiator for radiating the refrigerant received from the heat-generating electronic component 2 to the outside. Reference numeral 4 denotes a circulation path for connecting the centrifugal pump 1 and the radiator 3 to circulate the refrigerant. In addition, as this refrigerant, a harmless propylene glycol aqueous solution used for food additives and the like is appropriate, and when aluminum or copper is used as a casing material as described later, the anticorrosion performance against these is improved. It is desirable to add an anticorrosive additive for this purpose.
[0042]
The radiator 3 is made of a material having a high heat conductivity and good heat radiation, for example, a thin plate material such as copper or aluminum, and has a refrigerant passage and a reserve tank formed therein. Further, a fan may be provided to cool the radiator 3 by forcibly applying air to increase the cooling effect. The circulation path 4 is formed of a rubber tube made of a flexible and less gas-permeable rubber, for example, butyl rubber, in order to secure a degree of freedom in piping layout. This is to prevent air bubbles from entering the tube.
[0043]
Next, the internal configuration of the centrifugal pump 1 will be described. 2 to 6A and 6B, reference numeral 11 denotes an open impeller of a centrifugal pump, 11a denotes a through hole provided in the impeller 11, 12 denotes an open blade of the impeller 11, and 13 denotes a blade. This is a magnet rotor provided on the outer peripheral side of the vehicle 11. Reference numeral 14 denotes a stator provided on the inner peripheral side of the magnet rotor 13, reference numeral 15 denotes a pump casing which accommodates the impeller 11 and simultaneously recovers the kinetic energy given to the fluid by the impeller 11 and guides it to a discharge port. Reference numeral 15a denotes a blade. A pump chamber 15b for recovering the pressure of the kinetic energy given by 12 and guiding the kinetic energy to the discharge port is formed on a side surface of the pump casing 15 along the pump chamber 15a, and receives heat by contacting the heat-generating electronic components to remove heat. Surface, 15c is a pump chamber wall surface inside the pump chamber 15a, 16 is a casing cover for housing the impeller 11 and then sealing the pump chamber 15b, 17 is provided on the pump casing 15, and the impeller 11 is rotatable. A fixed shaft for supporting the shaft, 18 is a bearing provided at the center of the impeller 11 and mounted on the fixed shaft 17, and 18a is a dynamic pressure generating groove (a hydrodynamic bearing). It is a 4 reference). 19 is a suction path, 19a is a water intake, and 20 is a discharge path. Reference numeral 21 denotes a laminar flow boundary layer formed on the wall surface 15c of the pump chamber, a number of concave portions, 22 denotes a brush for scraping the laminar flow boundary layer (the elastic linear body of the present invention), and 22 denotes a blade for scraping the laminar flow boundary layer ( (Elastic plate of the present invention).
[0044]
The casing cover 16 is assembled with the pump casing 15 to constitute a pump casing of the centrifugal pump 1 as a whole. At least the pump casing 15 of the pump casing 15 and the casing cover 16 is made of a material having high heat conductivity and good heat dissipation, such as copper or aluminum. The centrifugal pump according to the first embodiment has a thickness in the rotation axis direction of 5 to 10 mm, a typical dimension in the radial direction of 40 to 50 mm, a rotation speed of 1200 rpm, a flow rate of 0.08 to 0.12 L / min, and a head. Is a pump of about 0.35 to 0.45 m. The specifications of the pump of the present invention, including the values of the first embodiment, include a thickness of 3 to 20 mm, a representative radial dimension of 10 to 70 mm, a flow rate of 0.01 to 0.8 L / min, and a head 0 .1 to 2 m. This is a specific speed of 24 to 28 (unit: m, m ³ / Min, rpm), which is a small and thin pump whose size is completely isolated from the conventional pump.
[0045]
In the centrifugal pump 1 according to the first embodiment, the blade 12 of the impeller 11 and the heat-generating electronic component 2 are installed so as to face each other, and the heat-receiving surface 15 b having a shape complementary to the upper surface of the heat-generating electronic component 2 is formed. The heat is directly received in the pump chamber 15a via the heat receiving surface 15b. The stator 14 is press-fitted into the casing cover 16, and the inner peripheral surface of the magnet rotor 13 and the outer peripheral portion of the stator 14 are arranged to face each other.
[0046]
A casing cover 16 is arranged between the stator 14 and the magnet rotor 13 as a separating plate separating the two, and the stator 14 is completely isolated from the refrigerant flowing in the pump chamber 15a. Although the impeller 11 may be configured separately from the magnet rotor 13, in the first embodiment, the impeller 11 is integrally formed and is formed as an integral impeller 11 magnetized on a cylindrical portion serving as the magnet rotor 13. When the magnet rotor 13 rotates by the action of the rotating magnetic field of the stator 14, the impeller 11 rotates. When the impeller 11 rotates, a negative pressure is generated near the center of the impeller 11, and the refrigerant is sucked from the communicating suction path 19, and the impeller 11 obtains momentum and is discharged outward.
A discharge port (not shown) is provided on the outer peripheral portion of the impeller 11, and the refrigerant is discharged to the circulation path 4 via the discharge path 20.
[0047]
A bearing 18 made of low-friction and wear-resistant ceramic is press-fitted into the center of the impeller 11, and a fixed shaft 17 made of ceramic is similarly fitted inside the pump 18 and the casing cover 16. Is fixedly arranged. As shown in FIG. 2, the outer peripheral surface of the bearing 18 is D-cut so that a gap is formed between the outer peripheral surface of the bearing 18 and a bearing press-fitting hole (not shown) of the impeller 11. It communicates with the chamber 15a side. This gap is the through hole 11a in the first embodiment, which is shifted from the axis center. A part of the refrigerant that has been pushed out by the centrifugal force of the impeller 11 by the through-hole 11a wraps around the back side of the impeller 11, and flows out through the through-hole 11a to the water suction port 19a of the impeller 11 in a negative pressure state. . That is, a part of the refrigerant is circulating in the centrifugal pump 1. The returning refrigerant is mixed in the water suction port 19a, and the returning refrigerant is replaced.
[0048]
The centrifugal force of the impeller 11 causes a negative pressure near the center of the impeller 11, which is in an environment where cavitation is likely to occur. However, the centrifugal pump 1 according to the first embodiment has a specific speed of 24 to 28 (unit: m, m ³ / Min, rpm), cavitation is unlikely to occur, and even if it occurs, it is mixed and discharged by the above-mentioned reflux. Then, even if the generated cavity tries to stay near the center of the impeller 11, the refrigerant circulates while being exchanged between the back surface of the impeller 11 and the water inlet 19a, so that the cavity does not stay. Also, even if air is mixed in somewhere in the cooling device and is sucked into the centrifugal pump 1, the air bubbles are gradually discharged without staying near the center of the impeller 11 due to the reflux. Therefore, the noise caused by cavitation is small, an air layer is not formed, and the flow becomes turbulent, so that the amount of heat transfer increases.
[0049]
Further, as shown in FIG. 4, a fluid bearing may be used instead of the bearing 18. If the dynamic pressure generating groove 18a of the fluid bearing is formed in a spiral shape to promote circulation, the bubble discharging performance can be improved. The shape of the dynamic pressure generating groove 18a may be a herringbone shape or the like. A groove may also be formed on the back of the impeller 11 to adjust the circulation amount and the back pressure. Thus, axial thrust with respect to the impeller 11 can be generated.
[0050]
Further, as shown in FIG. 5, by forming a large number of concave portions 21 in at least a part of a portion where the blade 12 slides on the wall surface 15 c of the pump chamber (the rear side of the heat receiving surface 15 b), the refrigerant flowing by the rotation of the impeller 11 is formed. Can separate the laminar flow boundary layer formed along the wall surface 15c of the pump chamber and cause turbulence. Thereby, the amount of heat transmitted from the heat receiving surface 15b to the refrigerant can be increased. Similarly, by forming or roughening the wall surface 15c of the pump chamber by shot peening, sandblasting, or the like, the heat receiving efficiency can be increased by a similar principle, albeit with a slightly lower effect. Further, as shown in FIG. 6, not only the blade 12 but also a brush 22 or a thin blade 23 which rubs the pump chamber wall surface 15c lightly is attached to the impeller, so that the rotational force of the impeller 11 forcibly applies. The laminar boundary layer is broken, and the heat receiving efficiency can be improved. Although not shown, even if a spiral groove is formed in the pump chamber wall surface 15c, the amount of heat transfer can be increased by turbulence.
[0051]
When the transfer coefficient from the casing to the refrigerant is sufficiently large compared to the heat generation amount, and when a large heat transfer amount is obtained, it is not necessary to spread the heat along the pump chamber 15a. The smaller the thickness, the better the heat receiving efficiency and the thinner the pump. For this purpose, as shown in FIG. 7, it is preferable that the suction passage 19 has an elliptical cross section having a short axis in the thickness direction. In order to increase the heat transfer area within a range where the rotation of the impeller 11 is not hindered, a small columnar body or rib or other protrusion is projected from at least a part of the portion of the pump chamber wall surface 15c where the side surface of the blade 12 slides. The heat area can be increased and turbulence can be promoted, so that the amount of heat received can be increased. Providing these pillars and ribs near the position where the center of the heat-generating electronic component 2 is placed increases the heat receiving efficiency. When the center of the heat-generating electronic component 2 is arranged at the center of the axis of the impeller 11, it may be set up near the center of the axis of the impeller 11.
[0052]
As described above, the centrifugal pump 1 of the cooling device according to the first embodiment is provided with the pump casing 15 made of a material having high thermal conductivity and the open impeller 11 having the blades 12 formed thereon. In addition, the shape of the heat receiving surface 15b and the upper surface of the heat-generating electronic component 2 are three-dimensionally complementary, and between the heat receiving surface 15c and the wall surface 15c of the pump chamber (the thick portion of the pump casing 15). Since the elliptical suction path 19 having a short axis in the thickness direction is provided, both the overall thickness and the substantial thickness near the flow path can be reduced, and the heat receiving surface 15b near the suction path 19 can be reduced. , The suction passage 19 does not protrude to the side of the heat-generating electronic component 2, so it is not necessary to change the shape of the heat-receiving surface 15 b due to the internal circumstances of the centrifugal pump 1. Because the surface can adhere Results to be able to heat.
[0053]
(Embodiment 2)
The centrifugal pump according to the second embodiment is characterized in that the water suction port is provided on the back side of the impeller. FIG. 8 is a configuration diagram of a heat exchange type centrifugal pump constituting a cooling device according to Embodiment 2 of the present invention, FIG. 9 is a front view of an impeller of the centrifugal pump according to Embodiment 2 of the present invention, and FIG. FIG. 11 is a configuration diagram of an impeller in which a centrifugal pump according to a second embodiment of the present invention has a rotating short axis, FIG. 11 is a front view of a pump chamber wall surface of the centrifugal pump according to the second embodiment of the present invention, and FIG. It is a lineblock diagram in which the pump casing thickness of the centrifugal pump in form 2 decreases in the radial direction. Since the centrifugal pump according to the second embodiment has the same components as the centrifugal pump according to the first embodiment, the description of the same reference numerals is omitted.
[0054]
In FIG. 8, reference numeral 19b denotes a water inlet connected to the suction passage 19, which is provided near the center of the impeller 11, and penetrates the back side and the pump chamber 15a side. The water inlet 19b is composed of three through holes provided at the same position in the radial direction as shown in FIG. The suction passage 19 is provided at the center of the stator 14 of the casing cover 16 and communicates with the water inlet 19b. The fixed shaft 17 and the bearing 18 are arranged in the same manner as in the first embodiment.
[0055]
By arranging the suction passage 19 on the side opposite to the heat receiving surface 15b, the thickness of the pump casing 15 on the heat receiving surface 15b side can be reduced, and the transfer coefficient from the casing to the refrigerant is smaller than the calorific value. When a sufficiently large heat transfer amount can be obtained, the heat need not be spread along the pump chamber 15a, and the heat receiving efficiency can be increased. By providing the water inlet 19b near the center of the impeller 11, the refrigerant can be sucked from the back of the impeller 11.
[0056]
In addition, as shown in FIGS. 10A and 10B, a configuration may be adopted in which the fixed shaft is removed and the refrigerant is sucked from the back surface of the impeller 11. In FIG. 10 (a), 16a is a casing cover, 16b is a cylindrical portion provided in the center of the casing cover 16a and provided with the suction passage 19 inside, 17a is a short rotating shaft provided in the center of the impeller 11, and 18b is A bearing 19c provided in the cylindrical portion 16b and supported by the rotation short shaft 17a inserted thereinto, and 19c is a water inlet formed by a through hole formed in the center of the shaft of the impeller 11. Reference numeral 24 denotes a projection such as a columnar body or a rib provided at the center of the wall surface 15c of the pump chamber facing the water inlet 19c. In the case of the second embodiment, the projection 24 is a column. In FIG. 10B, reference numeral 11c denotes an impeller protrusion provided on the inlet side of the blade 12 or between the blades 12.
[0057]
In this way, the suction port 19c allows the suction path 19 on the rear side to communicate with the pump chamber 15a, and suction from the rear side of the impeller 11 becomes possible. By suction from the side opposite to the heat-generating electronic component 2, a jet effect of directly injecting the refrigerant onto the pump chamber wall surface 15c of the heat receiving surface 15b is added, so that highly efficient heat reception is possible.
[0058]
In addition, since the protrusion 24 protrudes from the wall surface 15c of the pump chamber, the heat receiving area increases, and the amount of heat received can be greatly improved. Further, the turbulent flow is generated on the wall surface 15c of the pump chamber by the projections 24, so that the heat receiving efficiency can be improved.
Since the blades 12 are not present at the center of the impeller 11, it is easy to provide the projections 24 at this portion. In particular, the center of the heat-generating electronic component 2 is located at the center of the impeller 11 due to the installation balance. Therefore, by providing the protrusions 24 in this portion, the heat receiving efficiency can be locally improved. That is, since water is absorbed at the center of the impeller 11, providing the projections 24 at this position increases the heat transfer amount since the heat of the heat-generating electronic component 2 is the highest and the temperature difference with the refrigerant is the largest. In addition, since the heat transfer area is increased by providing the protrusions 24 at this portion, the heat resistance can be reduced, and the transfer of heat can be promoted. Further, improvement of the heat receiving efficiency by the jet effect can be expected. Then, a turbulent flow is generated in the projections 24, thereby improving the heat receiving efficiency. Note that a similar effect can be expected even if a groove is formed instead of the protrusion 24.
[0059]
Further, as shown in FIG. 10B, a projection 24 is provided on the inlet side of the blade 12 of the pump chamber 15a, and the stirring impeller projection 11c is arranged so as to mesh with the projection 24 in a radial direction. Is preferably provided. Desirably, the stirring impeller projection 11c is spirally arranged. In order to avoid contact, the projections 24 need to be provided facing each other at positions shifted in the radial direction so as not to be located concentrically with the stirring impeller projections 11c. Due to the stirring action of the stirring impeller protrusions 11c and the protrusions 24, turbulence is promoted on the inlet side of the blades 12, and the presence of the protrusions 24 may increase the heat radiation area, thereby greatly improving the heat receiving efficiency. I do. Experiments show that at 3000 rpm, the thermal conductivity of this configuration is 6000 W / m ² The vicinity of K is shown, and the maximum amount of heat can be radiated from the heat receiving surface 15b to the refrigerant.
[0060]
When the contact area of the heat-generating electronic component 2 is smaller than the rotation area of the blade 12 and it is necessary to spread the received heat to the side surface along the pump chamber 15a, the pump casing shown in FIG. As described above, the pump chamber wall surface 15c having the raised center contributes to the improvement of the heat receiving efficiency. In FIG. 12, reference numeral 15 d denotes a wall surface of the pump chamber configured so that the thickness of the pump casing 15 decreases in the radial direction around the axial center of the impeller 11. The heat flux is easy to flow through a portion having a small thermal resistance such as a large cross-sectional area or a large thermal conductivity, and the heat is transferred to the pump chamber 15a by forming the pump chamber wall surface 15d whose wall thickness decreases in the radial direction. Can extend to the side along.
[0061]
By the way, in the configuration of the centrifugal pump shown in FIG. 10, a herringbone-shaped groove or the like is formed on the inner circumferential surface and the outer circumferential surface of the magnet rotor 13 and the surface of the impeller 11 so that the impeller 11 The impeller 11 is held by dynamic pressure, and is supported between the bearing 18b of the cylindrical portion 16b of the casing cover 16a and the rotating short shaft 17a provided at the center of the impeller 11, so that the impeller 11 is stable with a simple configuration. Smooth rotation can be ensured and heat transfer can be promoted.
[0062]
(Embodiment 3)
In the centrifugal pump according to the third embodiment, the impeller 11 is formed into a disk shape, and the impeller 11 is magnetized. FIG. 13 is a configuration diagram of a heat exchange type centrifugal pump constituting a cooling device according to Embodiment 3 of the present invention. In FIG. 13, reference numeral 11b denotes a magnet provided on the rear surface of the impeller 11 so as to be magnetized. The magnet 11b may be formed by attaching a separate plate-shaped magnet to the impeller. Further, similarly to the first and second embodiments, in order to improve the heat receiving efficiency, it is also possible to provide a recess or a columnar body on the pump chamber wall surface 15c, a brush or a blade on the impeller 11, or to increase the thickness of the central portion. it can.
[0063]
As described above, the centrifugal pump 1 according to the third embodiment can be reduced in thickness in the axial direction, and is mounted on a small-sized portable electronic device such as a notebook computer. Cooling can be performed effectively.
[0064]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the cooling device of this invention, since the blade of an open-type impeller peels off the laminar boundary layer formed in a pump chamber, it becomes turbulent and heat transfer increases, and a suction path forms the heat receiving surface and the pump chamber. Since it is provided between the inner wall surface, the temperature of the heat receiving surface in the vicinity of the suction passage can be lowered, and since the suction passage does not protrude toward the heat-generating electronic components, the internal structure of the centrifugal pump is provided on the heat receiving surface. It is not necessary to form a change in shape due to the above, and since the heat receiving surface and the upper surface of the heat generating electronic component are in close contact, heat can be effectively received.
[0065]
Since it has an elliptical cross section having a short axis in the thickness direction, the distance between the pump chamber and the heat-generating component can be shortened, so that the thermal resistance therebetween can be reduced.
[0066]
Since the suction passage communicating with the water suction port is provided on the pump casing side facing the heat receiving surface, it is possible to suck in from the side opposite to the heat receiving surface of the pump chamber, and as a result, the distance between the pump chamber and the heat generating component is reduced. Therefore, the thermal resistance during that period can be reduced.
[0067]
Since the water inlet has an axial center coinciding with the axial center of the impeller, the flow rate can be sent most efficiently to maintain the symmetry of the flow in the impeller, and the heat can be effectively received. .
[0068]
Since the through hole is formed at a position deviated from the axial center of the impeller, it is possible to recirculate through the through hole from the back of the impeller of the pump chamber, and to discharge bubbles and cavities that easily stay at the center of the impeller. In addition, the heat transfer speed can be improved by eliminating the noise due to cavitation.
[0069]
On the pump chamber wall surface, a dynamic pressure groove is provided including a part where the side surface of the blade rotates, so the dynamic pressure groove makes the impeller rotate smoothly, suppresses the heat generated by friction, and reduces the heat receiving surface. The surface area of the back surface can be increased and heat can be effectively received. Since at least a part of the portion where the side surface of the blade slides is provided with a large number of concave portions for separating the laminar flow boundary layer, the laminar flow boundary layer having a small amount of heat transfer is separated, and heat transfer is promoted as a turbulent flow boundary layer. be able to. Since a large number of protrusions are provided on at least a part of the portion where the side surface of the blade slides, generation of turbulent flow of the refrigerant in the pump chamber can be promoted, and heat transfer can be promoted. Since a plurality of protrusions or grooves are provided on at least a part of the portion where the side surface of the blade slides, the generation of turbulent flow of the refrigerant in the pump chamber is promoted, and the heat transfer area is increased, thereby promoting heat transfer. be able to.
[0070]
A stirring impeller protrusion is formed on the inlet side of the blade or between the blades, and the stirring impeller protrusion stirs the flow path, so that the generation of turbulent refrigerant in the pump chamber can be promoted. Further, since the stirring impeller projection is provided at a position radially displaced from the projection formed on the inner wall of the pump chamber, the stirring impeller projection does not come into contact with the projection and the flow path does not contact the projection. Is effectively stirred, the generation of turbulent flow of the refrigerant in the pump chamber is promoted, the heat transfer area is increased, and the heat transfer efficiency can be further improved.
[0071]
An elastic linear body or an elastic plate-like body that is in contact with the surface of the inner wall of the pump chamber is provided on the side surface of the blade, so that the laminar boundary layer with small heat transfer is separated and heat transfer is promoted as a turbulent boundary layer. be able to. Since the thickness of the pump casing decreases in the radial direction around the axial center of the impeller, heat from the electronic components can be easily diffused to the entire pump chamber, and heat transfer can be promoted.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a cooling device according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a heat exchange type centrifugal pump constituting the cooling device according to the first embodiment of the present invention.
FIG. 3 is a front view of an impeller of the centrifugal pump according to the first embodiment of the present invention.
FIG. 4 is a development view of a fluid bearing of the centrifugal pump according to the first embodiment of the present invention.
FIG. 5 is an external view of a pump chamber wall surface of the centrifugal pump according to the first embodiment of the present invention.
FIG. 6 (a) is an explanatory view of a brush attached to an impeller of a centrifugal pump according to the first embodiment of the present invention.
(B) Explanatory drawing of the blade attached to the impeller of the centrifugal pump according to the first embodiment of the present invention.
FIG. 7 is a sectional view taken along line XX of the centrifugal pump of FIG. 2;
FIG. 8 is a configuration diagram of a heat exchange type centrifugal pump constituting a cooling device according to a second embodiment of the present invention.
FIG. 9 is a front view of an impeller of a centrifugal pump according to Embodiment 2 of the present invention.
FIG. 10 is a configuration diagram of an impeller in which a centrifugal pump according to Embodiment 2 of the present invention has a short rotating shaft.
FIG. 11 is a front view of a pump chamber wall surface of the centrifugal pump according to the second embodiment of the present invention.
FIG. 12 is a configuration diagram in which the pump casing thickness of the centrifugal pump according to the second embodiment of the present invention decreases in the radial direction.
FIG. 13 is a configuration diagram of a heat exchange type centrifugal pump constituting a cooling device according to a third embodiment of the present invention.
FIG. 14 is a configuration diagram of a first cooling device of a conventional electronic device.
FIG. 15 is a configuration diagram of a second cooling device of a conventional electronic device.
[Explanation of symbols]
1 Centrifugal pump
2 Heating electronic components
3 radiator
4 circulation path
11 Impeller
11a Through hole
11b magnet
11c Stirring impeller projection
12 feathers
13 Magnet rotor
14 Stator
15 Pump casing
15a Pump room
15b Heat receiving surface
15c, 15d Pump room wall surface
16, 16a Casing cover
16b tube
17 Fixed axis
17a Rotation short axis
18, 18b bearing
18a Dynamic pressure generating groove
19 Suction path
19a, 19b, 19c Water inlet
20 Discharge path
21 recess
22 brushes
23 blade
24 protrusion

Claims

A radiator and a contact heat exchange type centrifugal pump are provided in a closed circulation path for circulating the refrigerant, and the centrifugal pump is brought into contact with the heat-generating electronic component to remove heat from the heat-generating electronic component by a heat exchange action of the internal refrigerant. A cooling device for robbing and radiating heat from the radiator,
The centrifugal pump includes a pump casing and an open impeller made of a material having high thermal conductivity,
In the pump casing, a heat receiving surface is formed on a side surface along an internal pump chamber, and the heat receiving surface is formed in a shape complementary to a three-dimensional shape of an upper surface of the heat generating electronic component at a contact position. And a suction device is provided between the heat receiving surface and the inner wall surface of the pump chamber.

The cooling device according to claim 1, wherein the suction passage has an elliptical cross section having a short axis in a thickness direction of the pump casing.

2. The cooling device according to claim 1, wherein, instead of providing a suction passage between the heat receiving surface and the inner wall surface of the pump chamber, a suction port is formed at the center of the impeller, and the suction port communicates with the suction port. A cooling device, wherein a passage is provided on a pump casing side facing the heat receiving surface.

4. The cooling device according to claim 3, wherein the water inlet has an axial center coinciding with an axial center of the impeller.

The cooling device according to any one of claims 1 to 4, wherein a through hole is formed in the impeller at a position shifted from an axial center of the impeller.

The cooling device according to any one of claims 1 to 5, wherein a dynamic pressure groove is provided on a wall surface of the pump chamber at a portion where a side surface of the blade rotates.

The cooling according to any one of claims 1 to 6, wherein a large number of concave portions for separating the laminar flow boundary layer are provided on at least a part of a portion where the side surface of the blade slides on the inner wall of the pump chamber. apparatus.

The cooling device according to any one of claims 1 to 7, wherein a large number of protrusions are provided on at least a part of a portion where the side surface of the blade slides on the inner wall of the pump.

4. The cooling device according to claim 3, wherein a plurality of projections or grooves are provided on at least a part of a portion of the pump chamber wall facing the suction passage.

The cooling device according to any one of claims 1 to 9, wherein the impeller is provided with a stirring impeller protrusion at an inlet side of the blade or between the blades.

The cooling device according to claim 10, wherein the stirring impeller protrusion is provided at a position radially displaced from a protrusion formed on the inner wall of the pump chamber.

The cooling device according to any one of claims 1 to 11, wherein an elastic linear body or an elastic plate-like body that is in contact with a surface of the inner wall of the pump chamber is provided on a side surface of the blade.

The cooling device according to any one of claims 1 to 12, wherein a thickness of a pump casing of the heat receiving surface decreases in a radial direction around an axial center of the impeller.

A refrigerant circulation path;
A pump for circulating the refrigerant in the circulation path,
A radiator that emits heat of a refrigerant in the circulation path, and a cooling device for an electronic component,
The electronic component, wherein the pump is directly connected to the electronic component such that a housing of the pump and the electronic component are in thermal contact with each other, and a water inlet is provided in a central portion of a pump chamber of the pump. Cooling device.

15. The cooling device for an electronic component according to claim 14, wherein a water suction port is provided at a center of a pump chamber of the pump.

15. The cooling of the electronic component according to claim 14, wherein a separation means for separating a laminar flow boundary layer is provided on at least a part of a portion where the side surface of the impeller slides, on a pump chamber wall of the pump. apparatus.

The cooling device for an electronic component according to claim 14, wherein the peeling unit is provided with a concave portion or a protrusion at least on a wall of the pump chamber.

15. The cooling device for an electronic component according to claim 14, wherein the peeling means is provided with an elastic linear body or an elastic plate-like body which is in contact with a surface of the inner wall of the pump chamber on a side surface of the impeller.