JPH02108885A - Screw vacuum pump - Google Patents
Screw vacuum pumpInfo
- Publication number
- JPH02108885A JPH02108885A JP26152388A JP26152388A JPH02108885A JP H02108885 A JPH02108885 A JP H02108885A JP 26152388 A JP26152388 A JP 26152388A JP 26152388 A JP26152388 A JP 26152388A JP H02108885 A JPH02108885 A JP H02108885A
- Authority
- JP
- Japan
- Prior art keywords
- plating
- rotors
- cast iron
- casing
- vacuum pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000007747 plating Methods 0.000 claims abstract description 22
- 229910001018 Cast iron Inorganic materials 0.000 claims abstract description 13
- 229910001141 Ductile iron Inorganic materials 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims 1
- 238000005260 corrosion Methods 0.000 abstract description 25
- 230000007797 corrosion Effects 0.000 abstract description 25
- 238000005299 abrasion Methods 0.000 abstract description 8
- 230000007547 defect Effects 0.000 abstract description 2
- 238000005336 cracking Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 238000004381 surface treatment Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000000057 synthetic resin Substances 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- MROCJMGDEKINLD-UHFFFAOYSA-N dichlorosilane Chemical compound Cl[SiH2]Cl MROCJMGDEKINLD-UHFFFAOYSA-N 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 description 1
- 229910052982 molybdenum disulfide Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は腐食性ガスを排気するスクリュー真空ポンプで
あって安価な素材を用いて耐食性と耐摩耗性を向上させ
た真空ポンプに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw vacuum pump for exhausting corrosive gases, which uses inexpensive materials and has improved corrosion resistance and wear resistance.
スクリュー流体機械のスクリューロータ及びケーシング
に表面処理する例は従来数多〈実施されており、その主
目的は、特開昭５６−７５９９２号公報にみられるよう
に、軟質金属または合成樹脂をコーティングすることに
より、軟質材の弾性変形によりロータの接触を円滑にし
てガス漏れを防ぎ、圧縮効率を高めることである。しか
し耐蝕性は考慮されていないために、腐食性ガス雰囲気
での実用には不適である。また、特開昭５８−１４８２
９２号公報ではプラスチック、ゴム、二硫化モリブデン
などを塗布し、ロータ間のすきまを減少させて性能向上
を図っているが、接触が繰り返されるうちに表面皮膜が
損耗することが多く、このため耐食。Numerous examples of surface treatment have been carried out on the screw rotor and casing of screw fluid machines, and the main purpose thereof is to coat soft metals or synthetic resins, as seen in Japanese Patent Application Laid-Open No. 56-75992. By doing so, the elastic deformation of the soft material smoothes the contact between the rotors, prevents gas leakage, and improves compression efficiency. However, since corrosion resistance is not taken into account, it is unsuitable for practical use in corrosive gas atmospheres. Also, JP-A-58-1482
In Publication No. 92, the rotor is coated with plastic, rubber, molybdenum disulfide, etc. to reduce the gap between the rotors and improve performance. .
耐摩耗性にすぐれた表面皮膜の適用が必要とされていた
。There was a need for a surface coating with excellent wear resistance.
耐食性、耐摩耗性がともに良好な皮膜はＮｉメッキであ
るが、Ｎｉメッキの耐食性及び耐摩耗性は結晶構造で変
化し、かつ、鋳鉄を素材としその表面にメッキする場合
には変形、二次黒鉛の析出などを考慮した方法を開発す
る必要がある。The coating with good corrosion resistance and wear resistance is Ni plating, but the corrosion resistance and wear resistance of Ni plating change depending on the crystal structure, and when plated on the surface of cast iron, deformation and secondary It is necessary to develop a method that takes into account factors such as graphite precipitation.
上記従来技術のうち、軟質金属の代表例であるＡＱ及び
ｐｂは、酸やアルカリなどの腐食性ガスに対する耐食性
は著しく低いばかりでなく、その熱膨張率はＡＱが２３
．９Ｘ１０−６．Ｐｂが２９．ｌＸｌ０”−’と素材（
鋳鉄：１２Ｘ１０−”）に比べて著しく高く、熱膨張率
差により発生する応力によって皮膜破壊が生じることが
ある。一方１合成樹脂は耐食性は良好であるがその膨張
率は６０Ｘ１０−６〜８０Ｘ１０−８と金属に比べてさ
らに大きく、稼動中に剥離するなどの信頼性に大きな問
題があった。これに対してＮｉメッキは熱膨張率は約１
３Ｘ１０−”と素材の鋳鉄の熱膨張率と近似しており、
稼動中の剥離などの問題はない。しかし、Ｎｉメッキの
耐食性及び耐摩耗性は、Ｎｉメッキの結晶構造によって
著しく異なる。例えば、無電解Ｎｉメッキを例にとると
、通常はメッキのままあるいは２００℃以下の焼純状態
で使用されることが多いが、耐食性は良好であるが耐摩
耗性は著しく低い、このため耐摩耗性向上を目的として
熱処理を施し、硬さを高めることが行なわれている。Among the above conventional technologies, AQ and PB, which are typical examples of soft metals, not only have extremely low corrosion resistance against corrosive gases such as acids and alkalis, but also have a thermal expansion coefficient of 23.
．． 9X10-6. Pb is 29. lXl0"-' and material (
Cast iron: 12X10-") is significantly higher than that of cast iron, and the stress generated due to the difference in thermal expansion coefficient may cause film breakage. On the other hand, synthetic resin 1 has good corrosion resistance, but its expansion coefficient is 60X10-6 to 80X10- 8, which is even larger than that of metal, and had major reliability problems such as peeling during operation.On the other hand, Ni plating has a thermal expansion coefficient of approximately 1.
3X10-”, which is close to the coefficient of thermal expansion of the material cast iron,
There are no problems such as peeling during operation. However, the corrosion resistance and wear resistance of Ni plating vary significantly depending on the crystal structure of Ni plating. For example, if we take electroless Ni plating, it is usually used as plated or in the sintered state below 200°C, but although it has good corrosion resistance, its wear resistance is extremely low. In order to improve abrasion resistance, heat treatment is performed to increase hardness.
この場合、硬さの増加によって耐摩耗性は向上するが、
耐食性は逆に低下することがある。したがって、耐食性
と耐摩耗性が要求されるスクリュー真空ポンプで、この
耐食性と耐摩耗性を達成するための表面処理皮膜には、
素材の熱膨張率と近似し、かつ、耐食性と耐摩耗性の両
者に優れることが要求される。In this case, the increase in hardness improves wear resistance, but
On the contrary, corrosion resistance may decrease. Therefore, for screw vacuum pumps that require corrosion and abrasion resistance, the surface treatment film to achieve this corrosion and abrasion resistance is
It is required that the coefficient of thermal expansion is similar to that of the material, and that it has both excellent corrosion resistance and abrasion resistance.
本発明の目的はこの耐食性と耐摩耗性にすぐれた表面皮
膜を提供することにある。The object of the present invention is to provide a surface coating with excellent corrosion resistance and abrasion resistance.
上記目的は、鋳鉄より成るロータ、ケーシングを所定寸
法に機械加工し、その表面に無電解Ｎｉメッキを施し、
５００℃以上の温度でベーキングすることによって後加
工を施こすことなく達成される。The above purpose is to machine the rotor and casing made of cast iron to the specified dimensions, apply electroless Ni plating to the surface,
This is accomplished without post-processing by baking at a temperature of 500°C or higher.
第１表は約１０％のＰを含有する無電解Ｎｉメッキを球
状黒鉛鋳鉄表面に施しＮａＯＨ及びＮ ａ ＣＱ液中の
腐食電流を測定してその腐食性を検討したものである。Table 1 shows the results of electroless Ni plating containing about 10% P applied to the surface of spheroidal graphite cast iron, and corrosion currents in NaOH and Na CQ solutions measured to examine its corrosivity.
腐食電流値が高いことは腐食性が劣ることを示すもので
、Ｎｉメッキを施すことにより耐食性は著しく向上して
いる。第１図の線図は外径４０ｎｍ内径Ｌ６ｍｏの円筒
試験片の外径に約２０μｍ厚さの第１表と同じＮｉメッ
キを施し、相手材に同一形状の焼入した軸受鋼（ＳｕＪ
２）を用い、両部材に、乾燥ころがり摩耗試験を行なっ
た結果を示し、熱処理を施さない状態の摩耗は著しく多
く実用に供さず熱処理が必要となる。A high corrosion current value indicates poor corrosion resistance, and the corrosion resistance is significantly improved by applying Ni plating. The diagram in Figure 1 is a cylindrical test piece with an outer diameter of 40 nm and an inner diameter of L6mo.The outer diameter of the test piece is coated with the same Ni plating as in Table 1 with a thickness of about 20 μm, and the mating material is hardened bearing steel (SuJ
The results of a dry rolling abrasion test performed on both members using 2) are shown, and the wear without heat treatment is extremely high, making it unusable and requiring heat treatment.
第 １ 表 腐食電流（μＡ／ａ！１”）第２表は、第
１表の実験に供した同一試験片に熱処理を施したときの
腐食試験の結果で、５００℃以下の熱処理では耐食性は
著しく劣化する。これは３００℃以上の加熱によってＮ
ｉメッキに結晶構造がＮ１（１１０）のみからＮ１５Ｐ
などに変化するとともメッキ内部に多数の亀裂が発生
するからである。Table 1 Corrosion current (μA/a!1”) Table 2 shows the results of a corrosion test when the same test pieces used in the experiment in Table 1 were heat-treated. It deteriorates significantly.This is due to the N
The crystal structure of i-plating changes from only N1 (110) to N15P.
This is because a large number of cracks occur inside the plating when the plating changes.
第 ２ 表 腐食電流の変化
一方、熱処理温度を５００℃以上とすると、メッキ層内
の亀裂は減少または消減し、耐食性、耐摩耗性ともに著
しく向上するようになる。本処理はロータ、ケーシング
とも仕上げ加工後に行ない、処理後の仕上げは実施しな
い。そのため、メッキ処理及び熱処理による変形が問題
となるが、５００〜７００℃の加熱では性能を左右する
ような変形は発生せず問題はない、一方ケーシングは摩
擦や応力を受けることはなく、材質的にも普通鋳鉄で充
分であり、かつ、表面処理後の熱処理もとくに施すこと
なく使用できる。Table 2 Changes in Corrosion Current On the other hand, when the heat treatment temperature is set to 500°C or higher, cracks in the plating layer are reduced or eliminated, and both corrosion resistance and wear resistance are significantly improved. This treatment is performed after finishing the rotor and casing, and no finishing is performed after the treatment. Therefore, deformation due to plating and heat treatment is a problem, but heating at 500 to 700°C does not cause any deformation that affects performance, and there is no problem.On the other hand, the casing is not subjected to friction or stress, and the material Ordinary cast iron is sufficient for this purpose, and it can be used without any special heat treatment after surface treatment.
このように構成されたスクリュー真空ポンプは耐食、耐
摩耗性ともに著しく秀れ、信頼性の高い真空ポンプを供
給することができる。The screw vacuum pump constructed in this manner has excellent corrosion resistance and wear resistance, and can provide a highly reliable vacuum pump.
ケーシングがＦｅ１２．一対のロータがＦＣＤ５５から
成る２、２ＫＷ 、排気速度１０００Ｑ／ｍ１ｎ（５０
Ｈｚ）、到達圧力１０−”Ｔｏｒｒの半導体製造装置用
単段オイルフリースクリユー真空ポンプを製作し、半導
体チップエツチング用（ガス：Ｓ ｉ ＣＱ ａ及びＣ
ＣＱ４）及びナイトライド処理用（ガス：ジクロールシ
ラン及びアンモニア）真空ポンプに用いたところ、従来
表面処理が施してない状態ではポンプ停止後にさびが発
生したが、本実施例のポンプでは１年以上稼動している
にもかかわらず、さびの発生及び摩耗の問題はない。The casing is Fe12. A pair of rotors consists of FCD55, 2.2KW, exhaust speed 1000Q/m1n (50
Hz), a single-stage oil-free screw vacuum pump for semiconductor manufacturing equipment with an ultimate pressure of 10-'' Torr, and a single-stage oil-free screw vacuum pump for semiconductor chip etching (gas: S i CQ a and C
When used in a vacuum pump for CQ4) and nitride treatment (gas: dichlorosilane and ammonia), rust occurred after the pump was stopped without surface treatment, but with the pump of this example, it lasted for more than a year. Despite being in operation, there are no problems with rust or wear.
本発明によれば、腐食ガスと接触するロータ及びケーシ
ング表面は表面き裂など欠陥の無いＮｉメッキで被われ
ているため、耐食性は著しく向上する。また、雄雌ロー
タは接触しないように設計されているが、熱変形組立誤
差などによって互いに接触する場合があるが、その場合
でも耐摩耗性は良好で、信頼性の高い真空ポンプが得ら
れる。According to the present invention, the rotor and casing surfaces that come into contact with corrosive gas are covered with Ni plating free of defects such as surface cracks, so corrosion resistance is significantly improved. Further, although the male and female rotors are designed not to come into contact with each other, they may come into contact with each other due to thermal deformation and assembly errors, but even in that case, a vacuum pump with good wear resistance and high reliability can be obtained.
第１図は本発明を実施した試験片のころがり摩耗試験結
果を示す特性図である。
１・・・１６０℃ベーキング、２・・・４００℃ベーキ
ング、３・・・５５０℃ベーキング。FIG. 1 is a characteristic diagram showing the results of a rolling wear test of a test piece according to the present invention. 1...160℃ baking, 2...400℃ baking, 3...550℃ baking.
Claims (1)
された同一ケーシング内でかみ合せ、両ロータを共働さ
せて真空排気するスクリュー真空ポンプにおいて、両ロ
ータ表面及びケーシング内面に５０μｍ厚さ以下の無電
解Ｎｉメッキを施したことを特徴とするスクリュー真空
ポンプ。 ２、前記ロータが球状黒鉛鋳鉄またはバーミキユラ鋳鉄
、ケーシングが普通鋳鉄または球状黒鉛鋳鉄であること
を特徴とする請求項１記載のスクリュー真空ポンプ。 ３、ロータ及びケーシングに施されるメッキ組成が５〜
１０％のＰ及びその他の不純物から成り、かつ、ロータ
ではメッキ後５００℃以上でベーキング、ケーシングで
は２００℃以下または５００℃以上のベーキングを施し
たことを特徴とする請求項１記載のスクリュー真空ポン
プ。[Claims] 1. A screw vacuum pump in which a pair of male and female rotors made of cast iron are engaged in the same casing made of cast iron, and both rotors work together to evacuate the pump. and a screw vacuum pump characterized in that the inner surface of the casing is coated with electroless Ni plating with a thickness of 50 μm or less. 2. The screw vacuum pump according to claim 1, wherein the rotor is made of spheroidal graphite cast iron or vermicular cast iron, and the casing is made of ordinary cast iron or spheroidal graphite cast iron. 3. The plating composition applied to the rotor and casing is 5~
The screw vacuum pump according to claim 1, comprising 10% P and other impurities, and wherein the rotor is baked at 500°C or higher after plating, and the casing is baked at 200°C or lower or 500°C or higher. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26152388A JPH02108885A (en) | 1988-10-19 | 1988-10-19 | Screw vacuum pump |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26152388A JPH02108885A (en) | 1988-10-19 | 1988-10-19 | Screw vacuum pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02108885A true JPH02108885A (en) | 1990-04-20 |
Family
ID=17363086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26152388A Pending JPH02108885A (en) | 1988-10-19 | 1988-10-19 | Screw vacuum pump |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02108885A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6884049B2 (en) * | 2001-12-12 | 2005-04-26 | Hitachi, Ltd., | Screw compressor and method of manufacturing rotor for the same |
| JP2007168919A (en) * | 2005-12-19 | 2007-07-05 | Mutsuki:Kk | Rotary valve |
| CN102179520A (en) * | 2011-04-08 | 2011-09-14 | 无锡市汉力士液压泵制品有限公司 | Preparation method of nodular cast iron-bronze composite material for cylinder body of plunger pump |
-
1988
- 1988-10-19 JP JP26152388A patent/JPH02108885A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6884049B2 (en) * | 2001-12-12 | 2005-04-26 | Hitachi, Ltd., | Screw compressor and method of manufacturing rotor for the same |
| JP2007168919A (en) * | 2005-12-19 | 2007-07-05 | Mutsuki:Kk | Rotary valve |
| CN102179520A (en) * | 2011-04-08 | 2011-09-14 | 无锡市汉力士液压泵制品有限公司 | Preparation method of nodular cast iron-bronze composite material for cylinder body of plunger pump |
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