JP5486851B2

JP5486851B2 - Screw compressor

Info

Publication number: JP5486851B2
Application number: JP2009148188A
Authority: JP
Inventors: 裕敬亀谷; 利一内田; 誠司鶴; 隆史齋藤; 眞矢鈴木
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2009-06-23
Filing date: 2009-06-23
Publication date: 2014-05-07
Anticipated expiration: 2029-06-23
Also published as: JP2011007048A

Description

本発明は、スクリュー圧縮機に関わり、吸入ポートに関する。 The present invention relates to a screw compressor and relates to a suction port.

スクリュー圧縮機の性能すなわちエネルギ効率や体積効率を向上させるため、これまで多くの努力が費やされてきた。性能を決める要因は多々あるが、最近の研究から吸入ポートの輪郭形状がスクリュー圧縮機の性能、特に体積効率に影響することがわかってきた。 Many efforts have been expended in the past to improve the performance, ie energy efficiency and volumetric efficiency of screw compressors. Although there are many factors that determine performance, recent studies have shown that the profile of the suction port affects the performance of the screw compressor, particularly volumetric efficiency.

特開平６−２８８３６９号公報には、吸入ポートの輪郭について、一時的に容積変化が中断する作動室を備えたスクリュー圧縮機に好適な輪郭形状が開示されている。 Japanese Patent Application Laid-Open No. 6-288369 discloses an outline of a suction port suitable for a screw compressor having a working chamber in which volume change is temporarily interrupted.

また、特開平１０−９１６４号公報には、吸入動作を断続させることにより吸い込み流量を増す方法が開示されている。特開平６−２８８３６９号公報及び特開平１０−９１６４号公報は、各々適合する圧縮機の条件が限定されており、一般的かつ多くの圧縮機でその効果を享受するには至らなかった。 Japanese Patent Laid-Open No. 10-9164 discloses a method of increasing the suction flow rate by intermittently performing the suction operation. In JP-A-6-288369 and JP-A-10-9164, the conditions of the compressors that are suitable are limited, and the effects cannot be enjoyed with a general and many compressors.

また、同期歯車（タイミングギヤ）を備えたスクリュー圧縮機においては、ロータの歯と同期歯車の回転位相を精密に調整する必要がある。それを容易にする構造については特公昭６２−２１５７号公報に開示されている。また、その調整方法の改良に関しては、特開平１−１５５０８９号公報に開示されている。調整作業は、ロータの噛み合い部にゲージを挿入して、ロータ歯面間の隙間を確認しながら進めるのが一般的である。特公昭６２−２１５７号公報では、メインケーシングにあけた穴からゲージを入れ、調整後に蓋となる部材で塞ぐ構造を採用している。特開平１−１５５０８９号公報では、ゲージを使った手作業に代えてロータリエンコーダを使用してロータ間の隙間を確認している。 Further, in a screw compressor provided with a synchronous gear (timing gear), it is necessary to precisely adjust the rotational phase of the rotor teeth and the synchronous gear. A structure for facilitating this is disclosed in Japanese Patent Publication No. 62-2157. Further, improvement of the adjustment method is disclosed in Japanese Patent Laid-Open No. 1-155089. In general, the adjustment operation is performed by inserting a gauge into the meshing portion of the rotor and confirming the clearance between the rotor tooth surfaces. Japanese Examined Patent Publication No. 62-2157 adopts a structure in which a gauge is inserted through a hole formed in a main casing and is closed with a member which becomes a lid after adjustment. In Japanese Patent Laid-Open No. 1-155089, a gap between rotors is confirmed using a rotary encoder instead of manual work using a gauge.

特開平６−２８８３６９号公報JP-A-6-288369 特開平１０−９１６４号公報Japanese Patent Laid-Open No. 10-9164 特公昭６２−２１５７号公報Japanese Patent Publication No.62-2157 特開平１−１５５０８９号公報Japanese Unexamined Patent Publication No. 1-155089

上記した特開平６−２８８３６９号公報又は特開平１０−９１６４号公報は、適用できるスクリュー圧縮機の構造や使用方法に条件があり、広く一般的に適用するには至らなかった。そのため、多くのスクリュー圧縮機に適用できる吸い込み量を増すための構造を具体化することが課題となっていた。そこで、上記課題に鑑み本発明の第１の目的は、作動室への被圧縮のガスの吸い込みを無駄なく円滑にし、スクリュー圧縮機の作業効率（被圧縮のガスの吸い込み効率）を向上させることにある。 The above-mentioned Japanese Patent Application Laid-Open No. 6-288369 or Japanese Patent Application Laid-Open No. 10-9164 has a condition in the structure and method of use of an applicable screw compressor, and has not been widely applied in general. Therefore, it has been a problem to embody a structure for increasing the amount of suction applicable to many screw compressors. Accordingly, in view of the above problems, the first object of the present invention is to smoothly and smoothly suck the compressed gas into the working chamber and improve the working efficiency of the screw compressor (the compressed gas suction efficiency). It is in.

上記した特公昭６２−２１５７号公報は、同期歯車の調整に有効であるものの、調整に際して蓋を取り外し、調整後に再度取り付ける手間がかかる上に、蓋ならびにその着脱構造を設ける必要がある。蓋を省略する方法もあるが、位置によっては調整用の穴から作動室に一旦吸い込んだガスが噴出する逆流の流路となって、圧縮機性能を低下させてしまうことがある。特開平１−１５５０８９号公報も有効な手段であるもののロータリエンコーダ等の機器を調整対象である圧縮機に固定する作業が必要で、やはり手間がかかる難点があった。そこで、本発明の第２の目的は、性能低下をもたらすことなく、ロータの噛み合い部をケーシングの外から見えるようにし、ロータ対と同期歯車の回転位相調整を容易化することにある。 The above-mentioned Japanese Patent Publication No. 62-2157 is effective for adjusting the synchronous gear. However, it takes time and effort to remove the lid for adjustment and to reattach it after adjustment, and it is necessary to provide a lid and its attachment / detachment structure. Although there is a method of omitting the lid, depending on the position, there may be a reverse flow path through which the gas once sucked into the working chamber from the adjustment hole, and the compressor performance may be deteriorated. Japanese Patent Laid-Open No. 1-155089 is also an effective means, but it requires a work of fixing a device such as a rotary encoder to a compressor to be adjusted, and there is a problem that it takes time and effort. Therefore, a second object of the present invention is to make the meshing portion of the rotor visible from the outside of the casing without causing performance degradation, and to facilitate the rotational phase adjustment of the rotor pair and the synchronous gear.

上記課題を解決するために、被圧縮のガスを吸入して圧縮し、外部へ吐出するスクリュー圧縮機において、互いに噛み合った雄ロータ及び雌ロータと、前記雄ロータと前記雌ロータとを回転させる機構と、前記雄ロータ及び雌ロータとが収められたケーシングと、前記ケーシングに形成され、前記雄ロータ及び雌ロータの歯部を覆うボア部と、前記雄ロータの雄歯溝と前記雌ロータの雌歯溝との噛み合い部に形成された複数個の作動室と、前記ボア部の前記被圧縮のガスを吸入する側に設けられたアキシャル吸入ポートとを備え、前記アキシャル吸入ポートは、前記作動室の容積が略最大となる前記回転の回転角度において、前記外部と前記雌歯溝との連通、前記外部と前記雄歯溝との連通の順番に前記連通を止める形状である。 In order to solve the above problems, in a screw compressor that sucks and compresses a gas to be compressed and discharges the compressed gas to the outside, a male rotor and a female rotor meshing with each other, and a mechanism for rotating the male rotor and the female rotor A casing in which the male rotor and the female rotor are housed, a bore portion that is formed in the casing and covers the teeth of the male rotor and the female rotor, a male tooth groove of the male rotor, and a female of the female rotor A plurality of working chambers formed in a meshing portion with the tooth gap, and an axial suction port provided on a side of the bore portion for sucking the compressed gas, the axial suction port including the working chamber The communication is stopped in the order of the communication between the external and the female tooth groove, and the communication between the external and the male tooth groove, at the rotation angle at which the volume of the rotation is substantially maximum.

さらに、前記外部と雄歯溝との連通を止めた後の前記回転の回転角度において、前記作動室の前記被圧縮のガスを吸入する側は前記ボア部の壁面で覆われる。 Further, at the rotation angle of rotation after the communication between the exterior and the male tooth groove is stopped, the side of the working chamber that sucks in the gas to be compressed is covered with the wall surface of the bore portion.

また、被圧縮のガスを吸入して圧縮し、外部へ吐出するスクリュー圧縮機において、互いに噛み合った雄ロータ及び雌ロータと、前記雄ロータと前記雌ロータとを回転させる機構と、前記雄ロータ及び雌ロータとが収められたケーシングと、前記ケーシングに形成され、前記雄ロータ及び雌ロータの歯部を覆うボア部と、前記雄ロータの雄歯溝と前記雌ロータの雌歯溝との噛み合い部に形成された複数個の作動室と、前記ボア部の前記被圧縮のガスを吸入する側に設けられたアキシャル吸入ポートとを備え、前記アキシャル吸入ポートの輪郭は、前記作動室の容積が略最大となる前記回転の回転角度において、前記回転角度により前記雄ロータの後側となる前記被圧縮のガスを吸入する側の面での輪郭と、前記回転角度により前記雌ロータの後側となる前記被圧縮のガスを吸入する側の面での輪郭とを含み、前記回転方向と反対側に位置する前記被圧縮のガスを吸入する面を開口するとともに、前記回転方向側に位置する前記被圧縮のガスを吸入する面を塞ぐ。 In addition, in a screw compressor that sucks and compresses compressed gas and discharges the compressed gas to the outside, a male rotor and a female rotor engaged with each other, a mechanism for rotating the male rotor and the female rotor, and the male rotor and A casing in which a female rotor is housed, a bore portion that is formed in the casing and covers the teeth of the male rotor and the female rotor, and a meshing portion between the male tooth groove of the male rotor and the female tooth groove of the female rotor A plurality of working chambers formed on the bore portion and an axial suction port provided on a side of the bore portion for sucking the compressed gas, and the outline of the axial suction port is such that the volume of the working chamber is substantially the same. At the rotation angle of the rotation that becomes the maximum, the contour on the surface that sucks the gas to be compressed that is the rear side of the male rotor by the rotation angle, and the female rotor by the rotation angle And a contour of a surface on the side for sucking in the compressed gas that is on the side, opening a surface for sucking in the gas to be compressed located on the opposite side to the rotation direction, and positioned on the side in the rotation direction The surface for sucking the compressed gas is closed.

さらに、前記ボア部の外周面の一部であって、前記噛み合い部が開放される位置に設けられたラジアル吸入ポートを備える。 Furthermore, a radial suction port is provided which is a part of the outer peripheral surface of the bore portion and is provided at a position where the meshing portion is opened.

本発明によれば、スクリュー圧縮機の作業効率を向上させることが可能となる。 According to the present invention, the working efficiency of the screw compressor can be improved.

実施例１のロータ対と吸入ポートの輪郭を示す図である。It is a figure which shows the rotor pair of Example 1, and the outline of a suction port. 実施例１のボア部外周面の展開図である。FIG. 3 is a development view of the outer peripheral surface of the bore portion of the first embodiment. 従来のオイルフリー式スクリューの断面模式図である。It is a cross-sectional schematic diagram of a conventional oil-free screw. 従来のロータ対と吸入ポートの輪郭である。It is the outline of the conventional rotor pair and suction port. スクリュー圧縮機の作動室の容積変化と吸入流量のグラフである。It is a graph of the volume change of the working chamber of a screw compressor, and a suction flow rate.

実施例１を説明する前に、スクリュー圧縮機一般の吸入ポートについて、図３と図４を用いて説明する。図３は、一般的なスクリュー圧縮機の模式的断面図であり、図４は、噛み合った両ロータの斜視図にボア部の面に開けた吸入ポートの輪郭を重ね書きした図である。
このスクリュー圧縮機は、被圧縮のガスを吸入して圧縮し、外部へ吐出するものである。 Before describing the first embodiment, a general suction port of a screw compressor will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic cross-sectional view of a general screw compressor, and FIG. 4 is a diagram in which the outline of the suction port opened on the surface of the bore portion is overwritten on the perspective view of both rotors engaged with each other.
This screw compressor sucks and compresses a gas to be compressed and discharges it to the outside.

雄ロータ１と雌ロータ２は、互いに噛み合ってケーシング３の内部に形成したボア部４に収められている。すなわち、雄ロータ１と雌ロータ２は、ケーシング３に収められている。ボア部４は、雄ロータ１及び雌ロータ２の歯を形成した部分である歯部を覆うように、一部を重複した２つの円筒穴で形成されている。ボア部４の内面は、雌雄それぞれの円筒状外周面と両側の端面よりなる。図４でハッチングを施した雄ロータ１の歯溝５（以降、雄歯溝５という）と雌ロータ２の歯溝６（以降、雌歯溝６という）は、雄ロータ１と雌ロータ２とが噛み合った部分で連通するとともに、ボア部４の内面で囲われて、閉じた空間である作動室９を形成する。すなわち、作動室９は、雄歯溝５と雌歯溝６との噛み合い部に形成される。また、作動室９は、複数個形成される。雄ロータ１及び雌ロータ２の外周、噛み合い部及び端面には、ロータが円滑に回転するように微小な隙間が設けられているため、作動室９は厳密な意味では閉じた空間ではなく、隙間を通じて隣接する作動室とつながっている。しかし、これらの隙間やそこを通って漏れるガスの量は、微少量であり、本発明の主題に関係しないため、ここでは無視する。 The male rotor 1 and the female rotor 2 are housed in a bore portion 4 that is meshed with each other and formed inside the casing 3. That is, the male rotor 1 and the female rotor 2 are housed in the casing 3. The bore portion 4 is formed by two cylindrical holes that are partially overlapped so as to cover a tooth portion that is a portion where the teeth of the male rotor 1 and the female rotor 2 are formed. The inner surface of the bore portion 4 is composed of a male and female cylindrical outer peripheral surface and both end surfaces. The tooth groove 5 of the male rotor 1 hatched in FIG. 4 (hereinafter referred to as male tooth groove 5) and the tooth groove 6 of the female rotor 2 (hereinafter referred to as female tooth groove 6) are Are communicated at the meshed portion and surrounded by the inner surface of the bore portion 4 to form a working chamber 9 which is a closed space. That is, the working chamber 9 is formed at the meshing portion between the male tooth groove 5 and the female tooth groove 6. A plurality of working chambers 9 are formed. Since minute gaps are provided on the outer periphery, the meshing portion, and the end surface of the male rotor 1 and the female rotor 2 so that the rotor rotates smoothly, the working chamber 9 is not a closed space in a strict sense, but a gap It is connected to the adjacent working chamber through. However, these gaps and the amount of gas leaking through them are negligible and are ignored here because they are not relevant to the subject matter of the present invention.

雄ロータ１及び雌ロータ２の回転によって、作動室９は吸入側端面７上で生まれ、そこから吐出側端面８に向かって移動しながら、内容積を拡大する。内容積を拡大している間に、作動室９は、ケーシング３の外部まで連通するボア部４に開口した穴である吸入ポートに連通する。したがって、被圧縮のガスは、ケーシング３外部から吸入ポートを通って、作動室９に吸い込まれることになる。吸入ポートの輪郭線は、作動室９の容積がほぼ最大となった時に、作動室９との連通が終了し閉じられるように形成する。引き続き、作動室９は、図３又は図４ではロータ対の裏側に回りこみ、作動室９の内容積が縮小するので内部に閉じ込めたガスを圧縮することとなる。 Due to the rotation of the male rotor 1 and the female rotor 2, the working chamber 9 is created on the suction side end surface 7, and the internal volume is expanded while moving from there toward the discharge side end surface 8. While expanding the internal volume, the working chamber 9 communicates with a suction port which is a hole opened in the bore portion 4 communicating with the outside of the casing 3. Therefore, the gas to be compressed is sucked into the working chamber 9 from the outside of the casing 3 through the suction port. The outline of the suction port is formed so that the communication with the working chamber 9 is completed and closed when the volume of the working chamber 9 becomes almost maximum. Subsequently, in FIG. 3 or FIG. 4, the working chamber 9 turns around to the back side of the rotor pair, and the internal volume of the working chamber 9 is reduced, so that the gas trapped inside is compressed.

オイルフリー式スクリュー圧縮機において、雄ロータ１の歯面と雌ロータ２の歯面とは噛み合っているが、その間に微小な隙間を維持する必要がある。そこで、雄ロータ１及び雌ロータ２の軸端に、雄ロータ１と雌ロータ２とを回転させる機構である同期歯車１０を備え、回転伝達は同期歯車１０に任せている。したがって、同期歯車１０の雌雄間の回転位相とスクリュー歯の回転位相とは精密に調整しておく必要がある。その位相を詳細に見ると、同期歯車１０のバックラッシは、スクリュー歯のバックラッシの中に納まるような相対角度関係にしている。 In the oil-free screw compressor, the tooth surface of the male rotor 1 and the tooth surface of the female rotor 2 are engaged with each other, but it is necessary to maintain a minute gap therebetween. Therefore, the synchronous gear 10 that is a mechanism for rotating the male rotor 1 and the female rotor 2 is provided at the shaft ends of the male rotor 1 and the female rotor 2, and the rotation transmission is left to the synchronous gear 10. Therefore, it is necessary to precisely adjust the rotational phase between the male and female of the synchronous gear 10 and the rotational phase of the screw teeth. When the phase is viewed in detail, the backlash of the synchronous gear 10 is in a relative angular relationship so as to be accommodated in the backlash of the screw teeth.

実施例１を、図１を用いて説明する。図１は、噛み合った雄ロータ１及び雌ロータ２の斜視図にボア部４面上に開けた吸入ポートの輪郭を重ね書きした図である。作動室９は、最大容積となった位置にあり、それより手前側に並ぶ作動室は容積拡大による吸入過程にある。雄ロータ１と雌ロータ２は、図中の矢印方向に回転し、作動室は手前の吸入側端面７から奥方向にある吐出側端面８に向かって移動する。ボア部４の面に設けた吸入ポートは、吸入側端面７に開け、被圧縮のガスを吸入する側に設けられたアキシャル吸入ポート１１と、ボア部４の外周面であって、雄ロータ１と雌ロータ２との噛み合い部が開放される位置に設けられたラジアル吸入ポート１２の２つである。これら２つの吸入ポートは、吸入側端面７外周の角部でつながり１つの開口部となっているが、その形状から分けて説明する。 Example 1 will be described with reference to FIG. FIG. 1 is a diagram in which the outline of a suction port opened on the surface of the bore 4 is overwritten on the perspective view of the engaged male rotor 1 and female rotor 2. The working chamber 9 is at the position where the maximum volume is reached, and the working chambers arranged on the near side of the working chamber 9 are in the inhalation process by expanding the volume. The male rotor 1 and the female rotor 2 rotate in the direction of the arrow in the figure, and the working chamber moves from the front suction side end face 7 toward the discharge side end face 8 in the back direction. The suction port provided on the surface of the bore portion 4 is opened on the suction side end surface 7, is an axial suction port 11 provided on the side for sucking in the gas to be compressed, and the outer peripheral surface of the bore portion 4. And the radial suction port 12 provided at a position where the meshing portion between the female rotor 2 and the female rotor 2 is opened. These two suction ports are connected at the corner of the outer periphery of the suction side end face 7 to form one opening, which will be described separately from their shapes.

アキシャル吸入ポート１１の吸入側端面７上に表われる輪郭線は、７つの線で構成している。それらは、噛み合い部の線１３，雄歯底径に沿った円弧１４，雄歯形に沿った線１５，雄歯先径に沿った円弧１６，雌歯先径に沿った円弧１７，雌歯形に沿った線１８，雌歯底径に沿った円弧１９で一周を成す。このうち、圧縮機の性能に大きく影響する輪郭線は、雄歯形に沿った線１５と、雌歯形に沿った線１８であり詳しく説明する。 The contour line that appears on the suction side end face 7 of the axial suction port 11 is composed of seven lines. They are the meshing line 13, the arc 14 along the male root diameter, the line 15 along the male tooth profile, the arc 16 along the male tooth tip diameter, the arc 17 along the female tooth tip diameter, and the female tooth profile. A line 18 and a circular arc 19 along the female root diameter form a circle. Among these, the contour lines that greatly affect the performance of the compressor are the line 15 along the male tooth profile and the line 18 along the female tooth profile, which will be described in detail.

図１中にハッチングで示した最大容積の作動室９は、吸入側端面７にも雄歯溝５及び雌歯溝６で面している。吸入側端面７上に現れた歯溝の輪郭は、ロータの回転に対して先行する側と追従する側の２つに分けて考える。特に重要なのは、追従側で、吸入側端面７における雄歯溝５の追従側輪郭線２１と、雌歯溝６の追従側輪郭線２２に着目する。 The working chamber 9 having the maximum volume indicated by hatching in FIG. 1 also faces the suction side end face 7 with the male tooth groove 5 and the female tooth groove 6. The outline of the tooth groove appearing on the suction side end face 7 is considered as being divided into two sides, the preceding side and the following side with respect to the rotation of the rotor. Of particular importance is the following side, focusing on the following side contour line 21 of the male tooth groove 5 and the following side contour line 22 of the female tooth groove 6 on the suction side end face 7.

アキシャル吸入ポート１１の雄歯形に沿った線１５は、最大容積となる作動室９の吐出側端面８に面した雄歯溝５の追従側輪郭線２１に沿ったものとする。ただし、線１５を線２１に沿わせる精度は、ロータの直径の１／２０程度の誤差を許容できる。図１においては、区別して表現するため、吸入ポートの輪郭線１５と歯溝の追従側輪郭線２１を離して描いたが、実際には更に近い位置形状となる。 The line 15 along the male tooth shape of the axial suction port 11 is assumed to be along the follow-up side contour line 21 of the male tooth groove 5 facing the discharge side end face 8 of the working chamber 9 having the maximum volume. However, the accuracy of bringing the line 15 along the line 21 can allow an error of about 1/20 of the diameter of the rotor. In FIG. 1, for the sake of distinction, the contour 15 of the suction port and the follower contour 21 of the tooth gap are drawn apart from each other.

アキシャル吸入ポート１１の雌歯形に沿った線１８は、作動室９が最大容積となる回転角度より角度θｆだけ早期の回転位置における雌歯溝６の追従側輪郭線２２に沿ったものとする。したがって、図１に示す作動室９が最大容積となった瞬間には、追従側輪郭線２２はアキシャル吸入ポートを構成する線１８を通り過ぎた後となる。線１８の位置精度についても、ロータ直径の１／２０程度の誤差を許容できる。 The line 18 along the female tooth profile of the axial suction port 11 is assumed to be along the following contour 22 of the female tooth groove 6 at the rotational position earlier by the angle θf than the rotational angle at which the working chamber 9 has the maximum volume. Therefore, at the moment when the working chamber 9 shown in FIG. 1 reaches the maximum volume, the follow-up contour line 22 is after passing through the line 18 constituting the axial suction port. Regarding the position accuracy of the line 18, an error of about 1/20 of the rotor diameter can be allowed.

ラジアル吸入ポート１２は、雄ロータ１及び雌ロータ２の噛み合い部のうち吸入側端面７に近い部分が上方から見える位置に開口し、内容積が拡大途上で吸入過程にある作動室２９に連通している。その輪郭のうち作動室が進行方向にある輪郭線２３は、作動室２９の進行方向に対して先行する側の輪郭を形成する雄歯先線２４と雌歯先線２５に沿った形状とする。作動室２９は、最大容積となる作動室９の２つ手前側の作動室である。また、作動室２９の１つ先で最大容積の作動室９の１つ手前の作動室は、アキシャル吸入ポート１１に対して閉じた直後になっている。 The radial suction port 12 opens to a position where the portion close to the suction side end surface 7 of the meshing portions of the male rotor 1 and the female rotor 2 can be seen from above, and communicates with the working chamber 29 in the process of suction while the internal volume is expanding. ing. The contour line 23 in which the working chamber is in the traveling direction of the contour has a shape along the male tooth tip line 24 and the female tooth tip line 25 that form the contour on the side preceding the traveling direction of the working chamber 29. . The working chamber 29 is a working chamber two before the working chamber 9 having the maximum volume. Also, the working chamber 29 immediately after the working chamber 29 and before the working chamber 9 having the maximum volume is immediately after being closed with respect to the axial suction port 11.

作動室と吸入ポートとの位置関係がわかりやすいように、図２にボア部外周面の展開図を示す。中央の縦線３１は、雄側と雌側のボア部４の外周の円筒面の交線で膨張側カスプ３１と呼ぶ。左右両側の縦線３２は、どちらも図１で裏側にあるボア部外周面の交線である圧縮側カスプ３２を意味する。斜めの線は、雌雄それぞれの歯溝を区切る歯先線である。最大容積となった作動室９は、雄歯溝５と雌歯溝６で示される。ロータの回転により、雄歯溝５，雌歯溝６は、図２中の矢印の向きに上方に移動する。下の横線は吸入側端面７を意味し、上の横線は吐出側端面８を意味する。 FIG. 2 is a developed view of the outer peripheral surface of the bore so that the positional relationship between the working chamber and the suction port can be easily understood. The central vertical line 31 is called an expansion-side cusp 31 at the intersection of the outer cylindrical surfaces of the male and female bores 4. The vertical lines 32 on both the left and right sides mean the compression side cusp 32 that is an intersection line of the outer peripheral surface of the bore portion on the back side in FIG. The diagonal line is a tooth tip line that divides the male and female tooth spaces. The working chamber 9 having the maximum volume is indicated by a male tooth groove 5 and a female tooth groove 6. By the rotation of the rotor, the male tooth groove 5 and the female tooth groove 6 move upward in the direction of the arrow in FIG. The lower horizontal line means the suction side end face 7, and the upper horizontal line means the discharge side end face 8.

図２において、アキシャル吸入ポート１１はボア部の下に隣接して表記される開口部として示され、その雄側の輪郭線１５と雌側の輪郭線１８で、作動室９との連通があるか否かを判断できる。図２中に、アキシャル吸入ポート１１を重ね書きすることで、作動室２９との連通関係がわかりやすい。 In FIG. 2, the axial suction port 11 is shown as an opening that is described adjacently below the bore, and communicates with the working chamber 9 by its male contour 15 and female contour 18. It can be determined whether or not. By overwriting the axial suction port 11 in FIG. 2, the communication relationship with the working chamber 29 can be easily understood.

すなわち、アキシャル吸入ポート１１は、作動室９の容積が略最大となる雄ロータ１及び雌ロータ２の回転の回転角度において、圧縮機の外部と雌歯溝６との連通、圧縮機の外部と雄歯溝５との連通の順番に連通を止める形状である。また、圧縮機の外部と雄歯溝５との連通を止めた後の雄ロータ１及び雌ロータ２の回転の回転角度において、作動室９の被圧縮のガスを吸入する側はボア部４の壁面で覆われる。 That is, the axial suction port 11 communicates between the outside of the compressor and the female tooth groove 6 at the rotation angle of the rotation of the male rotor 1 and the female rotor 2 where the volume of the working chamber 9 is substantially maximum, It is a shape which stops communication in the order of communication with the male tooth groove 5. Further, in the rotation angle of the rotation of the male rotor 1 and the female rotor 2 after the communication between the outside of the compressor and the male tooth groove 5 is stopped, the side of the working chamber 9 that sucks in the gas to be compressed is the bore portion 4. Covered with walls.

また、アキシャル吸入ポート１１の輪郭は、作動室９の容積が略最大となる雄ロータ１及び雌ロータ２の回転の回転角度において、この回転角度により雄ロータ１の後側となる被圧縮のガスを吸入する側の面での輪郭と、この回転角度により雌ロータ２の後側となる被圧縮のガスを吸入する側の面での輪郭とを含み、この回転方向と反対側に位置する被圧縮のガスを吸入する面を開口するとともに、この回転方向側に位置する被圧縮のガスを吸入する面を塞ぐ。 Further, the outline of the axial suction port 11 is such that the compressed gas on the rear side of the male rotor 1 at the rotation angle of the male rotor 1 and the female rotor 2 at which the volume of the working chamber 9 becomes substantially maximum. Including a contour on the surface on the suction side and a contour on the surface on the suction side of the compressed gas that is the rear side of the female rotor 2 according to the rotation angle, and is located on the opposite side to the rotation direction. The surface for sucking in the compressed gas is opened, and the surface for sucking in the compressed gas located on the rotation direction side is closed.

以上で説明したスクリュー圧縮機は、以下のように作用する。 The screw compressor described above operates as follows.

図１ならびに図２において、ロータの回転によって、全ての作動室は、吸入側端面７から吐出側端面８に向かって移動しながら、内容積を拡大して最大容積の作動室９に至り、その後に内容積の縮小に転ずる。図５に、その内容積の変化を示すとともに、これを時間微分したグラフも併記する。内容積の変化を時間微分したグラフは、作動室に吸い込む体積流量が時間を追って変化する傾向を意味する。また、図５には、作動室に対しての各吸入ポートの開口期間を記載した。 1 and 2, the rotation of the rotor causes all the working chambers to move from the suction side end surface 7 toward the discharge side end surface 8, expanding the internal volume to reach the maximum volume working chamber 9, and thereafter It turns to the reduction of the internal volume. FIG. 5 shows a change in the internal volume, and also shows a graph obtained by time-differentiating the change. The graph obtained by differentiating the change in the internal volume with respect to time means a tendency that the volume flow rate sucked into the working chamber changes with time. FIG. 5 shows the opening period of each suction port with respect to the working chamber.

作動室は、回転角度θ₀において、吸入側端面７上で生じてから内容積が増加を続けるが、その間、作動室はアキシャル吸入ポート１１と連通を続ける。角度θ₁において、作動室の吸入側端面７に面する部分が、雄ロータ１側及び雌ロータ２側のそれぞれに分離する。これと、ほぼ同時期に、ボア部４の外周ｆにも面してラジアル吸入ポート１２とも連通を開始する。角度θ₁からしばらくの期間は、被圧縮のガスを吸入する流量が多くなるが、被圧縮のガスはアキシャル吸入ポート１１及びラジアル吸入ポート１２を通って作動室に吸い込まれる。アキシャル吸入ポート１１及びラジアル吸入ポート１２による広い開口面積であるために、通過するガスの圧力損失は小さく、被圧縮のガスを円滑に吸入することが可能である。 The working chamber continues to increase in internal volume after it occurs on the suction side end face 7 at the rotation angle θ ₀ , while the working chamber continues to communicate with the axial suction port 11. At the angle θ ₁ , the portion facing the suction side end surface 7 of the working chamber is separated into the male rotor 1 side and the female rotor 2 side. At substantially the same time, communication with the radial suction port 12 is started facing the outer periphery f of the bore 4. For a while from the angle θ ₁ , the flow rate for sucking the compressed gas increases, but the compressed gas is sucked into the working chamber through the axial suction port 11 and the radial suction port 12. Because of the wide opening area by the axial suction port 11 and the radial suction port 12, the pressure loss of the passing gas is small, and the compressed gas can be sucked smoothly.

雌歯溝３６の先頭が吐出側端面８に達すると、そこから先は容積拡大の速度が次第に低下し、吸入流量が減少に転じる。それと前後して、角度θ₂でラジアル吸入ポート１２が作動室に対して閉じられる。ここで着目すべきは、図２に示すように、雄歯溝３５の先頭が吐出側端面８に達するのは、雌歯溝３６の先頭が吐出側端面８に達するよりも後になることである。このため、雌歯溝３６への吸入流量が先に減少に転じても、ある程度の時間は雄歯溝３５への吸入流量は持続する。このため、雄歯溝３５及び雌歯溝３６が連通する噛み合い部においては、膨張側カスプ３１を横切って、流入し続ける雄歯溝３５から容積拡大が鈍化した雌歯溝３６への流れ３３が発生する。雄歯溝５内を進む吸入するガスの慣性も、雌歯溝６への流れ３３を増長させる。 When the leading end of the female tooth groove 36 reaches the discharge-side end face 8, the volume expansion speed gradually decreases thereafter, and the suction flow rate starts to decrease. Around that time, the radial suction port 12 is closed with respect to the working chamber at an angle θ ₂ . It should be noted here that, as shown in FIG. 2, the leading edge of the male tooth groove 35 reaches the discharge side end face 8 after the leading edge of the female tooth groove 36 reaches the discharge side end face 8. . For this reason, even if the suction flow rate into the female tooth groove 36 first decreases, the suction flow rate into the male tooth groove 35 continues for a certain period of time. Therefore, in the meshing portion where the male tooth groove 35 and the female tooth groove 36 communicate with each other, the flow 33 from the male tooth groove 35 that continues to flow into the female tooth groove 36 whose volume expansion has slowed across the expansion side cusp 31 is generated. Occur. The inertia of the inhaled gas traveling in the male tooth groove 5 also increases the flow 33 to the female tooth groove 6.

雌歯溝３６の吸入側端面７が開いているときに、雄歯溝３５から雌歯溝３６への流れ３３が強いと、吸入に対して逆流３４となってしまう。この逆流３４は、圧縮機の吸入流量を減らし効率を低下させるため好ましくない。実施例１において、アキシャル吸入ポート１１の雌側輪郭線１８は、雄側輪郭線１５よりも早めに閉じて、逆流３４を防止する効果があり、圧縮機の効率向上に寄与する。図５では、角度θ₃で雌歯溝３６に対するアキシャル吸入ポート１１を閉じる動作として示した。 When the suction side end face 7 of the female tooth groove 36 is open, if the flow 33 from the male tooth groove 35 to the female tooth groove 36 is strong, a reverse flow 34 occurs with respect to suction. This reverse flow 34 is not preferable because it reduces the suction flow rate of the compressor and lowers the efficiency. In the first embodiment, the female-side contour line 18 of the axial suction port 11 is closed earlier than the male-side contour line 15 and has an effect of preventing the backflow 34, which contributes to an improvement in the efficiency of the compressor. FIG. 5 shows an operation of closing the axial suction port 11 with respect to the female tooth groove 36 at an angle θ ₃ .

雌歯形に沿った線１８を早めに閉じることで、吸入ポートの開口面積が縮小し、圧損増加が懸念されることもある。しかし、図５に示したように、最大容積近くになると吸入流量が極端に小さくなるため、開口面積は雄側だけで十分確保されており、圧力損失が増加する問題がない。 By closing the line 18 along the female tooth shape early, the opening area of the suction port may be reduced, and an increase in pressure loss may be a concern. However, as shown in FIG. 5, since the suction flow rate becomes extremely small near the maximum volume, the opening area is sufficiently secured only on the male side, and there is no problem of increased pressure loss.

作動室容積が最大となる回転角度θ₄において、最後まで開口していた雄側のアキシャル吸入ポート１１が閉じられ、吸入過程が完了する。 At the rotation angle θ _{4 at} which the working chamber volume is maximized, the male-side axial suction port 11 that has been opened to the end is closed, and the suction process is completed.

ラジアル吸入ポート１２は、ガスの吸入流路としてだけではなく、同期歯車の固定位置を調整する際に雌雄歯面間の隙間にはさむゲージの挿入穴として使うことができる。開口部は歯の全長にわたる必要は無く、図１や図２に示したように軸方向に１歯分以上の長さがあれば十分である。同期歯車の固定位置を調整する方法については、特公昭６２−２１５７号公報及び特開平１−１５５０８９号公報に詳述されているので、ここでは簡潔に説明する。両ロータの間には連続的に細長く形成される隙間があり、この所定位置に隙間ゲージを挿入した状態で、同期歯車の回転位相を調整しながら軸に固定する。隙間ゲージの挿入作業に際して、雄ロータ１及び雌ロータ２の噛み合い部が半径方向から見えると作業性が良い。ゲージや作業者の手が入りやすく、その位置を容易に目視できるためである。実施例１のラジアル吸入ポート１２はその意味で都合のよい位置と大きさである。 The radial suction port 12 can be used not only as a gas suction flow path but also as an insertion hole for a gauge that is sandwiched between the male and female tooth surfaces when adjusting the fixed position of the synchronous gear. The opening does not need to extend over the entire length of the teeth, and it is sufficient if the opening has a length of one tooth or more in the axial direction as shown in FIGS. The method for adjusting the fixed position of the synchronous gear is described in detail in Japanese Patent Publication No. 62-2157 and Japanese Patent Application Laid-Open No. 1-155089, and will be briefly described here. There is a continuously elongated gap between the two rotors, and the gap gauge is inserted into this predetermined position, and the rotor is fixed to the shaft while adjusting the rotational phase of the synchronous gear. When inserting the clearance gauge, workability is good if the meshing portions of the male rotor 1 and the female rotor 2 can be seen from the radial direction. This is because the gauge and the operator's hand are easy to enter, and the position can be easily observed. The radial suction port 12 of the first embodiment has a convenient position and size in that sense.

ただし、過大なラジアル吸入ポート１２は、圧縮機性能を低下させることがわかっている。例えば、最大容積となる作動室９（すなわち雄歯溝５と雌歯溝６）の位置で閉じられるラジアル吸入ポート１２が幾何的に最大限で、図２で輪郭線２１と２２に連なる斜線がその輪郭の一部となる。このようなラジアル吸入ポートがあると、吸入流量が減少してきたときに、アキシャル吸入ポート１１から作動室９内に吸い込んだ被圧縮のガスが、慣性力や遠心力によりラジアル吸入ポート１２から出て逆流となってしまう。したがって、圧損を減じて吸い込み量を増やしたい意思に反し、逆流により吸い込み量を減らす悪影響が現れる。逆流した被圧縮のガスは、高温のロータやボア部の壁に触れて温度が上昇しているために、以降の作動室に再吸入されたとしても膨張していて質量流量を減少する悪影響を及ぼすこともある。 However, an excessive radial suction port 12 has been found to degrade compressor performance. For example, the radial suction port 12 that is closed at the position of the working chamber 9 (that is, the male tooth groove 5 and the female tooth groove 6) having the maximum volume is geometrically maximal, and the hatched lines connected to the contour lines 21 and 22 in FIG. It becomes a part of the contour. With such a radial suction port, when the suction flow rate decreases, the compressed gas sucked into the working chamber 9 from the axial suction port 11 exits from the radial suction port 12 due to inertial force or centrifugal force. It becomes a backflow. Therefore, contrary to the intention to reduce the pressure loss and increase the suction amount, there is an adverse effect of reducing the suction amount by backflow. The compressed gas that has flowed backward has increased the temperature by touching the walls of the high-temperature rotor and bore, so that even if it is re-inhaled into the subsequent working chamber, it expands and adversely affects the mass flow rate. May also affect.

これに対して、実施例１のように大きさを限定し、アキシャル吸入ポート１１よりも早期に閉じるラジアル吸入ポート１２は、逆流が発生しうる頃には既に閉じており、悪影響を及ぼさないか、あっても極めて微小ですむ。 On the other hand, the radial suction port 12 which is limited in size as in the first embodiment and closes earlier than the axial suction port 11 is already closed at the time when the backflow can occur and does not have an adverse effect? Even if it exists, it is extremely small.

実施例１において、アキシャル吸入ポート１１とラジアル吸入ポート１２は、個々に適用することも可能であり、その場合にも各々の効果を享受することができる。一方で、両者を共に備えた場合には、新たな相乗効果も享受できる。その相乗効果とは、吸入過程における圧損の低減による吸入量の増加である。作動室容積の変化ならびに吸入流量の変化は、図５に示すような傾向があるので、吸入流量の多い吸入過程中盤では吸入ポートの開口面積を広げて通過圧損を減らすことが望ましい。その一方で、最大容積に近づいて吸入流量が減る段階に至っては、先に述べたように開口面積は小さくてよく、かえって逆流を防止することが重要になる。 In the first embodiment, the axial suction port 11 and the radial suction port 12 can be applied individually, and even in that case, the respective effects can be enjoyed. On the other hand, when both are provided, a new synergistic effect can also be enjoyed. The synergistic effect is an increase in inhalation volume due to a reduction in pressure loss in the inhalation process. Since the change in the working chamber volume and the change in the suction flow rate tend to be as shown in FIG. 5, it is desirable to reduce the passage pressure loss by increasing the opening area of the suction port in the middle of the suction process where the suction flow rate is high. On the other hand, when reaching the maximum volume and reaching the stage where the suction flow rate decreases, the opening area may be small as described above, and it is important to prevent backflow.

実施例１のラジアル吸入ポート１２は、吸入量が増す吸入過程の中盤に開口しているため、通過圧損の低減に貢献しうるとともに、終盤においては閉塞しているため逆流を起こす悪影響がないという効果がある。 Since the radial suction port 12 of the first embodiment is opened in the middle of the suction process in which the suction amount increases, it can contribute to the reduction of the passage pressure loss, and it is closed at the end so that there is no adverse effect of causing backflow. effective.

実施例１によれば、吸入過程にある作動室が、円滑かつ低圧損で被圧縮のガスを吸入するとともに、最大容積となって吸入ポートを閉じる直前で発生する逆流を防止することができる。このため、スクリュー圧縮機の作業効率（被圧縮のガスの吸い込み効率）を向上させることが可能となる。 According to the first embodiment, the working chamber in the suction process sucks the gas to be compressed smoothly and with a low pressure loss, and can prevent the backflow that occurs immediately before the suction port is closed with the maximum volume. For this reason, it becomes possible to improve the working efficiency (intake efficiency of the gas to be compressed) of the screw compressor.

また、ラジアル吸入ポートから雌雄ロータの噛み合い部が見えるため、そこからゲージを歯面間に入れやすく、同期歯車を固定する際の調整が容易となる。よってスクリュー圧縮機の組み立てを迅速かつ精度よくすることが可能となる。 Further, since the meshing portion of the male and female rotors can be seen from the radial suction port, it is easy to put the gauge between the tooth surfaces from the radial suction port, and the adjustment when fixing the synchronous gear is facilitated. Therefore, the assembly of the screw compressor can be performed quickly and accurately.

作動室が最大容積となる直前での雌歯溝から吸入流路へ逆流を防止し、ガス運搬量を増す。また、噛み合い部の開口により同期歯車の調整が容易でありながら、性能低下のデメリットを生じない。 The backflow from the female tooth groove immediately before the working chamber reaches the maximum volume is prevented from flowing into the suction flow path, and the gas transport amount is increased. In addition, the adjustment of the synchronous gear is easy due to the opening of the meshing portion, but there is no demerit of performance degradation.

１雄ロータ
２雌ロータ
３ケーシング
４ボア部
５雄ロータの歯溝
６雌ロータの歯溝（これら歯溝が作動室９になる）
７吸入側端面
８吐出側端面
９作動室
１０同期歯車
１１アキシャル吸入ポート
１２ラジアル吸入ポート
１３〜１９アキシャル吸入ポートの輪郭を構成する個々の線
２１雄歯溝５の追従側輪郭線
２２雌歯溝６の追従側輪郭線
２３アキシャル吸入ポート１２の進行側輪郭線
２４雄歯先線
２５雌歯先線
２９作動室（内容積拡大中で吸入過程にある）
３１膨張側カスプ
３２圧縮側カスプ
３３雄歯溝から雌歯溝への流れ
３４雌歯溝からの逆流
３５吐出側に達する直前の雄歯溝
３６吐出側に達した雌歯溝 DESCRIPTION OF SYMBOLS 1 Male rotor 2 Female rotor 3 Casing 4 Bore part 5 Male rotor tooth space 6 Female rotor tooth space (these tooth spaces become the working chamber 9)
7 Suction side end face 8 Discharge side end face 9 Working chamber 10 Synchronous gear 11 Axial suction port 12 Radial suction ports 13-19 Individual lines 21 constituting the outline of the axial suction port 21 Follow-up line 22 of the male tooth groove 5 Female tooth groove 6 follow-up side contour line 23 advancing side contour line 24 of the axial suction port 12 male tooth tip line 25 female tooth tip line 29 working chamber (in the process of suction while the internal volume is expanding)
31 Expansion side cusp 32 Compression side cusp 33 Flow from male tooth groove to female tooth groove 34 Back flow from female tooth groove 35 Male tooth groove just before reaching discharge side 36 Female tooth groove reaching discharge side

Claims

In a screw compressor that sucks and compresses the gas to be compressed,
A male rotor and a female rotor meshing with each other;
A mechanism for rotating the male rotor and the female rotor;
A casing containing the male rotor and the female rotor;
A bore formed on the casing and covering the teeth of the male and female rotors;
A plurality of working chambers formed in a meshing portion between the male tooth groove of the male rotor and the female tooth groove of the female rotor;
An axial suction port provided on the side of the bore portion that sucks the compressed gas;
The axial suction port communicates in the order of communication between the exterior and the female tooth groove, and communication between the exterior and the male tooth groove, at the rotation angle of rotation until the volume of the working chamber becomes maximum. A screw compressor characterized by having a shape that stops.

The screw compressor according to claim 1,
The screw that sucks the compressed gas in the working chamber at the rotation angle after the communication between the outside and the male tooth groove is stopped, and is covered with the wall surface of the bore portion. Compressor.

The screw compressor according to claim 1,
The outline of the axial suction port is a surface on the side that sucks in the compressed gas that is behind the male rotor according to the rotation angle at the rotation angle until the volume of the working chamber becomes maximum. And a contour on a surface on the suction side of the compressed gas that is the rear side of the female rotor according to the rotation angle, and sucks the compressed gas positioned on the opposite side to the rotation direction. A screw compressor characterized by opening a surface to be closed and closing a surface for sucking the compressed gas positioned on the rotation direction side.

The screw compressor according to any one of claims 1 to 3,
A screw compressor, comprising: a radial suction port provided at a position on the outer peripheral surface of the bore portion where the meshing portion is opened.