JP5422260B2 - Oil-free screw compressor - Google Patents

Oil-free screw compressor Download PDF

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JP5422260B2
JP5422260B2 JP2009129389A JP2009129389A JP5422260B2 JP 5422260 B2 JP5422260 B2 JP 5422260B2 JP 2009129389 A JP2009129389 A JP 2009129389A JP 2009129389 A JP2009129389 A JP 2009129389A JP 5422260 B2 JP5422260 B2 JP 5422260B2
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rotor
rotors
oil
male
screw compressor
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JP2010275931A (en
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隆史 齋藤
誠司 鶴
利一 内田
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Hitachi Ltd
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Hitachi Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/082—Details specially related to intermeshing engagement type pumps
    • F04C18/086—Carter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/082—Details specially related to intermeshing engagement type pumps
    • F04C18/088—Elements in the toothed wheels or the carter for relieving the pressure of fluid imprisoned in the zones of engagement
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/0021—Systems for the equilibration of forces acting on the pump
    • F04C29/0035—Equalization of pressure pulses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/06—Silencing
    • F04C29/065—Noise dampening volumes, e.g. muffler chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/06—Silencing
    • F04C29/068—Silencing the silencing means being arranged inside the pump housing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/12—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2250/00—Geometry
    • F04C2250/10—Geometry of the inlet or outlet
    • F04C2250/102—Geometry of the inlet or outlet of the outlet

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Description

本発明は、１対の雄スクリューロータと雌スクリューロータとが形成する圧縮作動空間へ、油分を混入させないようにしたオイルフリースクリュー圧縮機に関する。   The present invention relates to an oil-free screw compressor in which oil is not mixed into a compression operation space formed by a pair of male screw rotor and female screw rotor.

一対のスクリューロータを組み合わせて圧縮作動空間を形成するスクリュー圧縮機には、この圧縮機を冷却するため及び一対のロータの円滑な駆動を可能にするため、圧縮作動空間に潤滑油を供給する給油式スクリュー圧縮機と、一対のロータをタイミングギアを介して駆動することによりロータ間の接触を回避し、圧縮作動空間への油分の混入を防止するオイルフリースクリュー圧縮機がある。   In a screw compressor that forms a compression working space by combining a pair of screw rotors, an oil supply that supplies lubricating oil to the compression working space in order to cool the compressor and to enable smooth driving of the pair of rotors. There is an oil-type screw compressor and an oil-free screw compressor that avoids contact between the rotors by driving a pair of rotors via a timing gear and prevents oil from entering the compression working space.

電子関連や食品、化学などの油分の混入を嫌う産業分野においては、オイルフリースクリュー圧縮機の需要が高い。しかしながら、空気圧縮機の電力費は、工場設備における電力費の約２５％にも上ると言われており、消費電力の少ないエネルギ効率の高い圧縮機が求められている。   In the industrial field that dislikes the mixing of oil such as electronics, food, and chemicals, there is a high demand for oil-free screw compressors. However, it is said that the power cost of the air compressor is about 25% of the power cost of the factory equipment, and an energy efficient compressor with low power consumption is required.

このような、従来のオイルフリースクリュー圧縮機の例が、特許文献１に記載されている。この特許文献１に記載のスクリュー圧縮機では、冷却された吐出ガスの一部を吸込み側に戻した結果圧縮機の動力が増大するという不具合を回避するために、吐出ポートに連通するロータ室壁部の位置よりも吐出ポート側で、吐出ポート近傍のロータ室内の空間部あるいは吐出開始直後の吐出口部分に、吐出流路中の吐出ガス冷却手段の出側で分岐させた分岐流路を合流させている。   An example of such a conventional oil-free screw compressor is described in Patent Document 1. In the screw compressor described in Patent Document 1, in order to avoid the problem that the power of the compressor increases as a result of returning a part of the cooled discharge gas to the suction side, the rotor chamber wall communicating with the discharge port A branch flow path branched on the outlet side of the discharge gas cooling means in the discharge flow path joins the space in the rotor chamber near the discharge port or the discharge port portion immediately after the start of discharge, closer to the discharge port than the position of the section I am letting.

また、オイルフリースクリュー圧縮機ではないが、給油式のスクリュー圧縮機の例が、特許文献２に記載されている。この公報に記載の圧縮機では、消費電力等の増大を抑制するために、ケーシングのロータ吐出側端面に対向する壁面に凹部を形成し、作動空間が吐出ポートと隔絶される直前に作動空間を凹部に連通させ、作動空間の容積が実質的に０になるまでこの連通を継続させている。   Moreover, although it is not an oil free screw compressor, the example of the oil supply type screw compressor is described in patent document 2. FIG. In the compressor described in this publication, in order to suppress an increase in power consumption and the like, a recess is formed in the wall surface facing the rotor discharge side end surface of the casing, and the working space is set immediately before the working space is isolated from the discharge port. The communication is continued to the recess until the volume of the working space becomes substantially zero.

特開昭６３−４５４８８号公報JP 63-45488 A 特開２００８−８２２７３号公報JP 2008-82273 A

上記特許文献１に記載のオイルフリースクリュー圧縮機では、吐出ガスを吐出ポートのできるだけ近傍で冷却することにより、吐出温度を低く抑え吸込み圧力の上昇を抑止して動力を低減している。しかしながらこの公報に記載のものでは、吐出ポート近傍に作動ガスが残って過圧縮が生じること等による動力の増加、すなわち複雑な吐出ポート部形状に起因する過圧縮等については、十分に考慮されていない。   In the oil-free screw compressor described in Patent Document 1, the discharge gas is cooled as close as possible to the discharge port, thereby lowering the discharge temperature and suppressing the increase of the suction pressure, thereby reducing the power. However, in the publication described in this publication, an increase in power due to the fact that working gas remains in the vicinity of the discharge port and over-compression occurs, that is, over-compression due to a complicated discharge port portion shape, etc. is sufficiently considered. Absent.

また、上記特許文献２に記載の給油式スクリュー圧縮機では、軸受に給油した潤滑油が作動空間へ混入するのを許容するので、油分の分離を機外で実施している。そのため、圧縮機本体の構造が簡素になっている。これに対して、オイルフリースクリュー圧縮機では、作動空間への油分の混入を防止するために、高性能な軸封装置が必要となっている。その結果、ロータ長が長くなるので高速回転機器における振動発生を抑制するために、ケーシングの端面深さ方向長さが著しく制限される。   Moreover, in the oil supply type screw compressor described in Patent Document 2, since the lubricating oil supplied to the bearing is allowed to enter the working space, the oil is separated outside the apparatus. Therefore, the structure of the compressor main body is simplified. On the other hand, an oil-free screw compressor requires a high-performance shaft seal device in order to prevent oil from entering the working space. As a result, since the rotor length becomes long, the length in the end surface depth direction of the casing is remarkably limited in order to suppress the occurrence of vibration in the high-speed rotating device.

また、この特許文献２に記載のものを、そのままオイルフリースクリュー圧縮機に適用すると、ロータ端面深さ方向に形成される溝の位置や形状により、吸込開始状態の圧縮作動空間内へ漏れる吐出側の圧縮空気の量を増加させる恐れがある。漏れ量が増えると、オイルフリースクリュー圧縮機の性能が、当然ながら低下する。   Further, when the one described in Patent Document 2 is applied to an oil-free screw compressor as it is, the discharge side leaks into the compression operation space in the suction start state due to the position and shape of the groove formed in the rotor end face depth direction. There is a risk of increasing the amount of compressed air. As the amount of leakage increases, the performance of the oil-free screw compressor naturally decreases.

本発明は、上記従来技術の不具合に鑑みなされたものであり、その目的は、オイルフリースクリュー圧縮機において、圧縮作動空間が０となる前に吐出ポートが閉じることに起因して生じる過圧縮等の不具合を防止することにある。本発明の他の目的は、過圧縮等にによる消費動力の増加または圧縮空気の過剰な温度上昇の発生を抑制することにある。本発明のさらに他の目的は、安価な製造方法で吐出ポートから圧縮作動空間が０となるタイミングまで圧縮空気を効率良く吐出させることが可能な吐出ポートを実現することにある。そして本発明は、少なくともこれらいずれかの目的を達成することを目的とする。   The present invention has been made in view of the above-described problems of the prior art, and the object thereof is an overcompression that occurs due to the discharge port closing before the compression working space becomes zero in an oil-free screw compressor. It is to prevent the troubles. Another object of the present invention is to suppress an increase in power consumption due to overcompression or the like, or an excessive temperature rise in compressed air. Still another object of the present invention is to realize a discharge port capable of efficiently discharging compressed air from the discharge port to a timing when the compression working space becomes zero by an inexpensive manufacturing method. The present invention aims to achieve at least one of these objects.

上記目的を達成する本発明の特徴は、複数のねじれた歯が形成された１対の雄スクリューロータおよび雌スクリューロータと、これら両ロータを収容し吸入ポートと吐出ポートとが形成されたケーシングと、両ロータの両軸端部を回転可能に支持しケーシングに保持された軸受と、両ロータの一方の軸端部に取付けられ両ロータを実質的に接触して同期回転させるタイミングギヤと、各軸受とロータの歯との間に配置され、ロータの噛み合い部に油が侵入するのを防止する軸封装置とを備えるオイルフリースクリュー圧縮機において、両ロータの回転に伴い両ロータとケーシングとにより形成される圧縮作動空間の容量が実質的にゼロとなる、雄スクリューロータの歯先と雌スクリューロータの歯底が最接近する領域と吐出ポートを繋ぐ溝を、前記雄スクリューロータの歯先外径より外側に設け、前記溝は、前記雌スクリューロータの歯底円と前記雄スクリューロータの歯先円との交じわる位置近傍から、両ロータの中心を結ぶ線まで延びていることにある。 A feature of the present invention that achieves the above object is a pair of male screw rotor and female screw rotor formed with a plurality of twisted teeth, and a casing that accommodates both the rotors and has a suction port and a discharge port formed therein. A bearing that rotatably supports both shaft ends of both rotors and held in the casing, a timing gear that is attached to one shaft end of both rotors and substantially rotates the rotors in synchronization with each other; An oil-free screw compressor that is disposed between a bearing and a rotor tooth and includes a shaft seal device that prevents oil from entering the meshing portion of the rotor. capacity of the compressed working space formed becomes substantially zero, the grooves connecting the region with the discharge port tooth bottom of the tooth tip and female screw rotors of the male screw rotor is closest Wherein provided on the outside of the tooth tip outer diameter of the male screw rotor, wherein the groove is from serious Waru position near the addendum circle of the tooth bottom circle of the female screw rotor male screw rotor, connecting the centers of both rotors It extends to the line .

そしてこの特徴において、溝は、雄スクリューロータの歯先部から外方に延びており、その幅が軸方向深さよりも大きいことが望ましい。また、溝を切削加工で形成して、吐出側から吸込み側への漏れを防止するのがよい。 In this feature, it is desirable that the groove extends outward from the tooth tip portion of the male screw rotor, and the width thereof is larger than the axial depth. Moreover, it is preferable to form a groove by cutting to prevent leakage from the discharge side to the suction side.

本発明によれば、圧縮作動空間の容積が実質的にゼロになるまで吐出ポートに連通する手段をオイルフリースクリュー圧縮機に設けたので、過圧縮等の不具合を防止できる。また、過圧縮等による消費動力の増加または圧縮空気の過剰な温度上昇の発生も抑制できる。さらに、安価な製造方法で吐出ポートから圧縮作動空間が実質的にゼロとなるタイミングまで圧縮空気を効率良く吐出させることができる。 According to the present invention, since the means for communicating with the discharge port is provided in the oil-free screw compressor until the volume of the compression working space becomes substantially zero, problems such as overcompression can be prevented. In addition, an increase in power consumption due to overcompression or the like, or an excessive temperature rise in compressed air can be suppressed. Furthermore, the compressed air can be efficiently discharged from the discharge port to a timing at which the compression working space becomes substantially zero by an inexpensive manufacturing method.

本発明に係るオイルフリースクリュー圧縮機の一実施例の要部横断面図。The principal part cross-sectional view of one Example of the oil-free screw compressor which concerns on this invention. 図１のＡ−Ａ断面図。AA sectional drawing of FIG. 図１のＢ−Ｂ断面図。BB sectional drawing of FIG. 図１のＣ−Ｃ断面図。CC sectional drawing of FIG. 本発明にオイルフリースクリュー圧縮機の一実施例の平面断面図（ａ）及び正面断面図（ｂ）。The plane sectional view (a) and front sectional view (b) of one example of the oil free screw compressor in the present invention.

以下、本発明に係るオイルフリースクリュー圧縮機の一実施例を、図面を用いて説明する。初めにオイルフリースクリュー圧縮機の概要を、図５を用いて説明する。図５（ａ）は、オイルフリースクリュー圧縮機５０の平面断面図であり、同図（ｂ）は正面断面図である。オイルフリースクリュー圧縮機５０は、１対の雄のスクリューロータ１と雌のスクリューロータ２を有しており、これら１対のロータ１、２はケーシング３に形成されたボアに収容されている。ボアは、円筒状の２個の空間が軸方向に直角な方向に連接したもので、互いの軸心が平行になっている。   Hereinafter, an embodiment of an oil-free screw compressor according to the present invention will be described with reference to the drawings. First, an outline of the oil-free screw compressor will be described with reference to FIG. FIG. 5A is a plan sectional view of the oil-free screw compressor 50, and FIG. 5B is a front sectional view. The oil-free screw compressor 50 has a pair of male screw rotors 1 and a female screw rotor 2, and the pair of rotors 1 and 2 are accommodated in a bore formed in the casing 3. The bore is formed by connecting two cylindrical spaces in a direction perpendicular to the axial direction, and their axial centers are parallel to each other.

各ロータ１、２の一方の軸端部は、軸受１１、１２で、他方の軸端部は軸受１３、１４で回転可能に支持されている。軸受１１〜１４は、ケーシング３に保持されている。軸受１１〜１４には潤滑油が供給される。本発明に係るスクリュー圧縮機５０は、オイルフリー圧縮機なので、後述する作動空間へ潤滑油が侵入するのを防止するために、各軸受よりも軸方向中央側には、軸封装置３１〜３４が設けられている。   One shaft end portion of each rotor 1, 2 is supported by bearings 11, 12, and the other shaft end portion is rotatably supported by bearings 13, 14. The bearings 11 to 14 are held in the casing 3. Lubricating oil is supplied to the bearings 11 to 14. Since the screw compressor 50 according to the present invention is an oil-free compressor, in order to prevent the lubricating oil from entering a working space described later, shaft seal devices 31 to 34 are provided at the axially central side of the bearings. Is provided.

雌ロータ２の一方の軸端には、ピニオンギア２１が取付けられており、このピニオンギア２１は図示しない原動機に噛み合っている。雄ロータ１及び雌ロータ２には、タイミングギヤ２２、２３が取付けられており、両タイミングギヤ２２、２３がかみ合うことにより、雄ロータ１と雌ロータ２とは同期回転する。   A pinion gear 21 is attached to one shaft end of the female rotor 2, and this pinion gear 21 meshes with a prime mover (not shown). Timing gears 22 and 23 are attached to the male rotor 1 and the female rotor 2, and the male rotor 1 and the female rotor 2 rotate synchronously when the timing gears 22 and 23 are engaged with each other.

雄ロータ１と雌ロータ２の軸方向中間部は大径に形成されている。各ロータ１、２の大径部は、ケーシング３に形成したボアの内壁面との間にわずかな隙間を有して保持される。また、各ロータ１、２の大径部には、スパイラル状に複数の溝または歯が形成されている。本実施例では、雄ロータ１が４枚の歯を、雌ロータ２が６本の溝を有している。そして、雄ロータ１の歯が雌ロータ２の溝に、わずかな隙間を保ちながら噛み合っている。   A middle portion of the male rotor 1 and the female rotor 2 in the axial direction is formed with a large diameter. The large diameter portion of each rotor 1, 2 is held with a slight gap between the inner wall surface of the bore formed in the casing 3. In addition, a plurality of grooves or teeth are formed in a spiral shape in the large diameter portion of each of the rotors 1 and 2. In this embodiment, the male rotor 1 has four teeth and the female rotor 2 has six grooves. The teeth of the male rotor 1 mesh with the grooves of the female rotor 2 while maintaining a slight gap.

雄ロータ１およびメスロータ２の一方側（図５では右側）には、吸込み口から吸込まれた空気を両ロータ１、２とケーシング３により形成される作動空間に導く吸込みポートが形成されている。両ロータ１、２の軸方向反対側には、両ロータ１、２およびケーシング３により形成された作動空間から機外に圧縮空気を導く吐出ポート４が形成されている。   On one side (right side in FIG. 5) of the male rotor 1 and the female rotor 2, a suction port is formed that guides air sucked from the suction port to an operating space formed by the rotors 1, 2 and the casing 3. A discharge port 4 is formed on the opposite side of the rotors 1 and 2 in the axial direction to guide the compressed air from the working space formed by the rotors 1 and 2 and the casing 3 to the outside of the machine.

吐出ポート４の詳細を、図１に示したスクリュー圧縮機５０の横断面図及び図１の各部断面である図２ないし図４を用いて説明する。図２は、図１のＡ−Ａ矢視断面図で、雄ロータ１の吐出部近傍を示す図である。図３は、図２のＢ−Ｂ矢視断面図で、雄ロータ１と雌ロータ２の噛み合い部で吐出ポート４近傍を示す図である。図４は、雄ロータ１と雌ロータ２の噛み合い部付近のＣ−Ｃ矢視断面図で水平断面を示す図である。   Details of the discharge port 4 will be described with reference to FIG. 2 to FIG. 4 which are cross-sectional views of the screw compressor 50 shown in FIG. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 and shows the vicinity of the discharge portion of the male rotor 1. FIG. 3 is a cross-sectional view taken along the line B-B in FIG. 2, and shows the vicinity of the discharge port 4 at the meshing portion of the male rotor 1 and the female rotor 2. FIG. 4 is a cross-sectional view of the vicinity of the meshing portion between the male rotor 1 and the female rotor 2 and shows a horizontal cross section.

ところで、オイルフリースクリュー圧縮機５０では、空気は、吸入配管を通ってケーシング３内に導かれる。そして、１対の雄ロータ１と雌ロータ２とこれらロータ１、２を収容するケーシング３から構成される圧縮作動空間の容積が、ロータ１、２の回転に伴って拡大して圧縮機内部に吸入される。その後、圧縮作動空間が最大容積となる付近でケーシング３により完全に閉じられ、さらにロータ１、２の回転が進むと、圧縮作動空間が収縮する。これにより、空気の圧力が上昇する。   Incidentally, in the oil-free screw compressor 50, the air is guided into the casing 3 through the suction pipe. Then, the volume of the compression working space composed of the pair of male rotors 1 and female rotors 2 and the casing 3 that accommodates these rotors 1 and 2 expands with the rotation of the rotors 1 and 2 and enters the compressor. Inhaled. After that, the compression working space is completely closed by the casing 3 in the vicinity of the maximum volume, and when the rotation of the rotors 1 and 2 further proceeds, the compression working space contracts. Thereby, the pressure of air rises.

圧縮作動空間が所定の容積まで収縮した状態に合わせて、ロータ１、２の軸方向端面部であって外径部付近に、ロータ１、２の歯形の輪郭形状に合わせて吐出ポートを形成する。この吐出ポートから圧縮空気を吐出する。雄雌両ロータ１、２同士及びロータ１、２とケーシング３間はお互いが接触しないように、ロータ１、２及びケーシング３の加工精度や熱膨張や空気圧力による変形、軸受隙間を考慮して隙間を形成する。オイルフリースクリュー圧縮機５０では、この隙間から空気が漏れると性能が低下する。したがって、隙間を可能な限り小さくすれば、性能が向上する。しかしながら、ケーシング３の形状は、複雑にならざるを得ず、一般的には鋳物で製作する。吸入ポート及び吐出ポート形状も鋳物で形成するが、高精度が必要な部分は機械加工で製作する。   In accordance with the state in which the compression working space is contracted to a predetermined volume, a discharge port is formed in the axial end surface portion of the rotors 1 and 2 and in the vicinity of the outer diameter portion according to the contour shape of the tooth profile of the rotors 1 and 2. . Compressed air is discharged from this discharge port. Considering the processing accuracy of the rotors 1, 2 and the casing 3, deformation due to thermal expansion and air pressure, and bearing clearance so that the male and female rotors 1, 2 and between the rotors 1, 2 and the casing 3 do not contact each other. Create a gap. In the oil-free screw compressor 50, when air leaks from this gap, the performance is degraded. Therefore, performance is improved if the gap is made as small as possible. However, the shape of the casing 3 must be complicated, and is generally manufactured by casting. The shape of the suction port and discharge port is also formed by casting, but parts that require high accuracy are manufactured by machining.

特に、吐出ポート４は、過圧縮による消費動力の増加や圧縮空気温度上昇を避けるため、圧縮作動空間がゼロとなるタイミングまで圧縮空気を吐出できるように開口部を形成するのが望ましい。しかし、鋳物や機械加工での形成が困難であるのと、コストが増大するので、ロータ１、２の端面に隙間を許容している。この隙間からは圧縮空気が逃げるので、吐出ポートを圧縮作動空間がゼロとなるタイミングまで開口させずとも、実質的に過圧縮を防止できる。   In particular, the discharge port 4 is preferably formed with an opening so that compressed air can be discharged until the compression working space reaches zero, in order to avoid an increase in power consumption and an increase in compressed air temperature due to overcompression. However, if the formation by casting or machining is difficult, the cost increases, so that a clearance is allowed between the end faces of the rotors 1 and 2. Since the compressed air escapes from this gap, over-compression can be substantially prevented without opening the discharge port until the compression working space becomes zero.

しかしながら、この従来の方法では、過圧縮を防止できるが、常に端面から圧縮空気が逃げるので、性能低下はやむをえない。そこで本発明では簡単な構成で、端面からの漏れを低減させながら、過圧縮も防止している。   However, although this conventional method can prevent over-compression, since the compressed air always escapes from the end face, performance degradation is unavoidable. Therefore, in the present invention, over-compression is prevented with a simple configuration while reducing leakage from the end face.

なお、以下の説明は理論的な説明なので、雄ロータ１と雌ロータ２がその歯面上で接するものとしているが、上述したように、実際のオイルフリースクリュー圧縮機では、歯面が接触すると摩擦・摩耗及び振動・騒音を生じるので、熱膨張を考慮しても接触しない程度に、隙間を形成する。しかしながら、この隙間は非常に小さいので、実質的な考察では接触するものとみなしても何等かまわない。   Since the following explanation is a theoretical explanation, it is assumed that the male rotor 1 and the female rotor 2 are in contact with each other on the tooth surface. However, as described above, in an actual oil-free screw compressor, when the tooth surface is in contact with each other. Since friction / wear and vibration / noise are generated, a gap is formed to such an extent that contact does not occur even when thermal expansion is considered. However, since this gap is very small, even if it considers that it contacts in substantial consideration, it does not matter.

図１において、各ロータ１、２の回転方向をＤＩＲで表している。雄ロータ１と雌ロータ２とが同期して回転すると、雄ロータ１の歯面であって先に雌ロータ２の歯面に接触する面である前進面ＳＦ１が、雌ロータ２の歯面ＳＲ２と噛み合い、ケーシング３の内壁面との間で、作動空間７を形成する。この作動空間７は、雄ロータ１及び雌ロータ２の回転とともに軸方向吸込み側から吐出側に移動する。その際、シールラインと呼ばれる雄ロータ１と雌ロータ２の仮想的な接触線により作動空間は仕切られる。このシールラインの後端が、両ロータ１、２の吸込み端壁部３ａに達したときに、作動空間７の容積は実質的にゼロになる。図１は、この作動空間７の容積が０になった状態を、示した図である。   In FIG. 1, the rotation direction of each rotor 1 and 2 is represented by DIR. When the male rotor 1 and the female rotor 2 rotate in synchronization, the forward surface SF1 that is the tooth surface of the male rotor 1 and first contacts the tooth surface of the female rotor 2 is the tooth surface SR2 of the female rotor 2. And the working space 7 is formed between the inner wall surface of the casing 3. This working space 7 moves from the axial suction side to the discharge side as the male rotor 1 and the female rotor 2 rotate. At that time, the working space is partitioned by a virtual contact line between the male rotor 1 and the female rotor 2 called a seal line. When the rear end of this seal line reaches the suction end wall 3a of both rotors 1, 2, the volume of the working space 7 becomes substantially zero. FIG. 1 is a view showing a state in which the volume of the working space 7 becomes zero.

すなわち、雄ロータ１と雌ロータ２とは、歯面上の点Ｐ１，Ｐ２，Ｐ３で接触している。点Ｐ１，Ｐ２で両端を区切られ雄ロータ１の前進面ＳＦ１と雌ロータ２の歯面ＳＲ２間に、圧縮作動空間が形成されている。一方、雄ロータ１の前進面ＰＦ１とは反対歯面ＳＲ１と雌ロータ２の前進面ＳＦ２及び点Ｐ２，Ｐ３により新たな圧縮作動空間８が形成されている。   That is, the male rotor 1 and the female rotor 2 are in contact at points P1, P2, and P3 on the tooth surface. Both ends are separated by points P1 and P2, and a compression operation space is formed between the advance surface SF1 of the male rotor 1 and the tooth surface SR2 of the female rotor 2. On the other hand, a new compression working space 8 is formed by the tooth surface SR1 opposite to the advance surface PF1 of the male rotor 1, the advance surface SF2 of the female rotor 2, and the points P2 and P3.

このような圧縮作動空間形状の変化に対応して、従来から吐出ポートが形成されている。図２に示すように、各ロータ１、２の吐出側端面近傍であって、ケーシング３の下側部分に、圧縮作動室に接続する吐出流路３１が形成されている。そして、ケーシング３の側壁部分は、図で破線で示すように、雄ロータ２の次に噛み合う歯の反前進面ＳＲ１、雄ロータ２の歯底円、雌ロータ２の次に噛み合う歯の前進面とは反対面ＳＲ２、雌ロータ２の歯底円、雄ロータ１及び雌ロータ２の歯先円をそれぞれ結んだ形状に開口している。   A discharge port has been conventionally formed in response to such a change in the shape of the compression working space. As shown in FIG. 2, a discharge flow path 31 connected to the compression working chamber is formed in the vicinity of the discharge side end face of each rotor 1, 2 and in the lower part of the casing 3. The side wall portion of the casing 3 is, as indicated by a broken line in the figure, the anti-advance surface SR1 of the teeth meshing next to the male rotor 2, the root circle of the male rotor 2, and the advance surface of the teeth meshing next to the female rotor 2. Are opened in a shape connecting the opposite surface SR2, the root circle of the female rotor 2, and the tip circles of the male rotor 1 and female rotor 2, respectively.

さらに本発明では、上述したように性能を低下させることなく過圧縮を防止させるため、実質的に作動空間の容積がゼロになっても、圧縮空気を吐出可能とする吐出ポート加工溝６を形成している。この加工溝６の詳細を、以下に説明する。   Furthermore, in the present invention, in order to prevent over-compression without degrading the performance as described above, the discharge port machining groove 6 is formed that can discharge compressed air even when the volume of the working space becomes substantially zero. doing. Details of the processed groove 6 will be described below.

図１に示すように、加工溝６は、雄ロータ１の歯先と雌ロータ２の歯底との噛合い部近傍に位置している。吐出側から吸込側への空気の漏れを防止するため、吐出ポート４と吸込開始状態の圧縮作動空間８とが連通しないように、雄ロータ１の歯先外径より外側に加工溝６を位置させる。さらに、吐出完了状態の圧縮作動空間７が可能な限り吐出ポート４に連通するように、吐出側のロータ１の端面とケーシング３との隙間δ程度（図２参照）の隙間分だけ、雄ロータ１の歯先外径より外側に位置させる。   As shown in FIG. 1, the machining groove 6 is located in the vicinity of the meshing portion between the tooth tip of the male rotor 1 and the tooth bottom of the female rotor 2. In order to prevent air leakage from the discharge side to the suction side, the machining groove 6 is positioned outside the tooth tip outer diameter of the male rotor 1 so that the discharge port 4 and the compression working space 8 in the suction start state do not communicate with each other. Let Further, the male rotor is provided by a gap of about δ (see FIG. 2) between the end surface of the rotor 1 on the discharge side and the casing 3 so that the compression working space 7 in the discharge completion state communicates with the discharge port 4 as much as possible. 1 is located outside the tooth tip outer diameter.

雌ロータ２の軸封装置３４部へ圧縮空気が漏れるのを低減するため、加工溝６の幅は可能な限り小さくする。加工溝６の深さ、すなわち軸方向の寸法εは、軸封装置３４を備えることにより制限されるが、溝の幅寸法δの１／２程度とする（図４参照）。加工溝６の長さＷは、上述した吐出ポート４のコーナ部、すなわち雌ロータ２の歯底部と雄ロータ１の歯先部との交わり部から始まり、雄ロータ１と雌ロータ２の軸中心を結ぶ線までとする。 In order to reduce the leakage of compressed air to the shaft seal device 34 of the female rotor 2, the width of the machining groove 6 is made as small as possible. The depth of the processed groove 6 , that is, the dimension ε in the axial direction is limited by providing the shaft seal device 34, but is about ½ of the groove width dimension δ (see FIG. 4). The length W of the machining groove 6 starts from the corner portion of the discharge port 4 described above, that is, from the intersection of the tooth bottom portion of the female rotor 2 and the tooth tip portion of the male rotor 1, and the axial center of the male rotor 1 and the female rotor 2. Up to the line connecting

加工溝６の諸元をこのように定めるのは、以下の理由による。加工溝６の長さＷをこれ以上延ばすと、すなわち雄ロータ１と雌ロータ２の中心を結ぶ線を越えると、吸入開始の溝と連続してしまい、吸入側へ圧縮空気が逆流する。また、加工溝６深さεは、加工性を考慮して定める。さらに、加工溝６の幅δを広げすぎると、雌ロータ２の軸封部の孔に近づきすぎて、圧縮空気が軸封部に流れてしまう。これらの理由から、加工溝６の寸法を上記のように定めている。 The specification of the machining groove 6 is determined in this way for the following reason. If the length W of the processing groove 6 is further extended, that is, if the line connecting the centers of the male rotor 1 and the female rotor 2 is exceeded, it continues to the suction start groove, and the compressed air flows backward to the suction side. Further, the processing groove 6 depth ε is determined in consideration of workability. Furthermore, if the width δ of the processing groove 6 is excessively widened, it will be too close to the hole in the shaft seal portion of the female rotor 2 and compressed air will flow into the shaft seal portion. For these reasons, the dimensions of the processed groove 6 are determined as described above.

１…雄（スクリュー）ロータ、２…雌（スクリュー）ロータ、３…ケーシング、４…吐出ポート、５…圧縮作動空間、６…（吐出ポート）加工溝、７…吐出完了状態の圧縮作動空間、８…吸込開始状態の圧縮作動空間、１１〜１４…軸受、２１…ピニオンギヤア、２２、２３…タイミングギヤ、３１〜３４…軸封装置、５０…オイルフリースクリュー圧縮機。 DESCRIPTION OF SYMBOLS 1 ... Male (screw) rotor, 2 ... Female (screw) rotor, 3 ... Casing, 4 ... Discharge port, 5 ... Compression operation space, 6 ... (Discharge port) processing groove, 7 ... Compression operation space of a discharge completion state, DESCRIPTION OF SYMBOLS 8 ... Compression working space of the suction start state, 11-14 ... Bearing, 21 ... Pinion gear, 22, 23 ... Timing gear, 31-34 ... Shaft seal device, 50 ... Oil-free screw compressor.

Claims (3)

複数のねじれた歯が形成された１対の雄スクリューロータおよび雌スクリューロータと、これら両ロータを収容し吸入ポートと吐出ポートとが形成されたケーシングと、前記両ロータの両軸端部を回転可能に支持しケーシングに保持された軸受と、前記両ロータの一方の軸端部に取付けられ両ロータを実質的に接触して同期回転させるタイミングギヤと、前記各軸受と前記ロータの歯との間に配置され、ロータの噛み合い部に油が侵入するのを防止する軸封装置とを備えるオイルフリースクリュー圧縮機において、
前記両ロータの回転に伴い両ロータとケーシングとにより形成される圧縮作動空間の容量が実質的にゼロとなる、雄スクリューロータの歯先と雌スクリューロータの歯底が最接近する領域と吐出ポートを繋ぐ溝を、前記雄スクリューロータの歯先外径より外側に設け、
前記溝は、前記雌スクリューロータの歯底円と前記雄スクリューロータの歯先円との交じわる位置近傍から、両ロータの中心を結ぶ線まで延びていることを特徴とするオイルフリースクリュー圧縮機。 A pair of male and female screw rotors formed with a plurality of twisted teeth, a casing in which both rotors are accommodated to form suction ports and discharge ports, and both shaft ends of the rotors are rotated. A bearing that is supported and held in the casing, a timing gear that is attached to one shaft end of the two rotors and substantially rotates the rotors in contact with each other, and the bearings and teeth of the rotor In an oil-free screw compressor provided with a shaft seal device disposed between and preventing oil from entering the meshing portion of the rotor,
An area where the tooth tip of the male screw rotor and the tooth bottom of the female screw rotor are closest to each other, and the discharge port , in which the capacity of the compression working space formed by both the rotor and the casing becomes substantially zero as the rotors rotate Is provided outside the tooth tip outer diameter of the male screw rotor ,
The groove extends from the vicinity of the position where the root circle of the female screw rotor and the tooth tip circle of the male screw rotor intersect to a line connecting the centers of the two rotors. Machine. 前記溝は、前記雄スクリューロータの歯先部から外方に延びており、その幅が軸方向深さよりも大きいことを特徴とする請求項１に記載のオイルフリースクリュー圧縮機。 2. The oil-free screw compressor according to claim 1, wherein the groove extends outward from a tooth tip portion of the male screw rotor and has a width larger than an axial depth . 前記溝を切削加工で形成して、吐出側から吸込み側への漏れを防止したことを特徴とする請求項１または２に記載のオイルフリースクリュー圧縮機。 The oil-free screw compressor according to claim 1 or 2, wherein the groove is formed by cutting to prevent leakage from the discharge side to the suction side .
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CN101900119A (en) 2010-12-01
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CN101900119B (en) 2013-10-30
EP2264319A2 (en) 2010-12-22
JP2010275931A (en) 2010-12-09

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