JP2017031821A

JP2017031821A - Oil-cooled screw compressor

Info

Publication number: JP2017031821A
Application number: JP2015149772A
Authority: JP
Inventors: 貴徳今城; Takanori Imashiro; 洋武山崎; Hiromu Yamazaki; 吉村　省二; Seiji Yoshimura; 省二吉村
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2015-07-29
Filing date: 2015-07-29
Publication date: 2017-02-09
Anticipated expiration: 2035-07-29
Also published as: JP6521781B2

Abstract

PROBLEM TO BE SOLVED: To improve performance by reducing an agitation loss of oil in a discharge side bearing, in an oil-cooled screw compressor.SOLUTION: An oil-cooled screw compressor 2 is equipped with a casing 4 provided with a compression chamber and a bearing chamber. A pair of screw rotors 8 and 9 engaged with each other is disposed in the compression chamber. A discharge side bearing 16 which rotatably supports discharge side end portions of the disposed screw rotors 8 and 9 is disposed in the bearing chamber. A shaft seal device 14 separating the compression chamber and the bearing chamber is provided between them, and an oil draining path 44 for draining oil from a bearing upstream space 24 provided between the discharge side bearing 16 and the shaft seal device 14 is provided.SELECTED DRAWING: Figure 1

Description

本発明は、油冷式スクリュ圧縮機に関する。 The present invention relates to an oil-cooled screw compressor.

油冷式空気スクリュ圧縮機では油の撹拌ロスが重要な問題であり、スクリュロータの軸受における撹拌ロスがその主要因である。圧縮機の軸受は油により冷却及び潤滑され、常に油が通過する構造となっている。よって、軸受メーカーが想定している油浴状態とは異なり、軸受による油の流れへの抵抗により軸受上流側の油面が上昇し、油と軸受の接触面積が増大し、油の撹拌ロスが増加する。 In oil-cooled air screw compressors, oil agitation loss is an important issue, and agitation loss in screw rotor bearings is the main factor. The compressor bearings are cooled and lubricated by oil, and the oil always passes through. Therefore, unlike the oil bath state assumed by the bearing manufacturer, the oil level on the upstream side of the bearing rises due to the resistance to the oil flow by the bearing, the contact area between the oil and the bearing increases, and the oil agitation loss is reduced. To increase.

特許文献１には、油冷式スクリュ圧縮機の軸受部分の排油構造が開示されている。この油冷式スクリュ圧縮機では、軸受の外輪抑えスリーブに環状空間を設けることで、油が軸受下流の空間に溜まることによる撹拌ロスを防止している。 Patent Document 1 discloses an oil drain structure of a bearing portion of an oil-cooled screw compressor. In this oil-cooled screw compressor, an annular space is provided in the outer ring restraining sleeve of the bearing, thereby preventing agitation loss due to oil remaining in the space downstream of the bearing.

特開平１０−２８８１７５号公報JP-A-10-288175

特許文献１の油冷式スクリュ圧縮機は、軸受下流側の油量の溜まりは考慮しているが、軸受上流側の油面位置や軸受を通過する油量について考慮されていない。 The oil-cooled screw compressor of Patent Document 1 considers the accumulation of the oil amount on the downstream side of the bearing, but does not consider the oil surface position on the upstream side of the bearing and the amount of oil passing through the bearing.

本発明は、軸受における油の撹拌ロスの低減による、油冷式スクリュ圧縮機の性能の向上を課題とする。 An object of the present invention is to improve the performance of an oil-cooled screw compressor by reducing oil agitation loss in a bearing.

本発明は、圧縮室と軸受室が内部に設けられたケーシングと、前記圧縮室に配置された互いに噛合する一対のスクリュロータと、前記軸受室に配置された前記スクリュロータの吐出側端部を回転自在に支持する吐出側軸受と、前記圧縮室と前記軸受室とを隔離する吐出側軸封と、前記吐出側軸受と前記吐出側軸封との間に設けられた前記軸受室から排油する排油経路とを備える、油冷式スクリュ圧縮機を提供する。 The present invention includes a casing in which a compression chamber and a bearing chamber are provided, a pair of screw rotors disposed in the compression chamber and meshing with each other, and a discharge side end portion of the screw rotor disposed in the bearing chamber. Oil is discharged from the discharge-side bearing that is rotatably supported, the discharge-side shaft seal that separates the compression chamber and the bearing chamber, and the bearing chamber that is provided between the discharge-side bearing and the discharge-side shaft seal. An oil-cooled screw compressor including an oil discharge path for performing the operation is provided.

吐出側軸受と吐出側軸封との間に排油経路を設けたことで、吐出側軸受の上流側に溜まる余分な油を排油できる。従って、吐出側軸受の上流側に必要以上に油が溜まることを防止でき、吐出側軸受における油の撹拌ロスを低減できる。 By providing an oil drain path between the discharge side bearing and the discharge side shaft seal, it is possible to drain excess oil that accumulates on the upstream side of the discharge side bearing. Accordingly, it is possible to prevent oil from being accumulated more than necessary on the upstream side of the discharge side bearing, and to reduce oil agitation loss in the discharge side bearing.

前記排油経路の排油先は、前記スクリュロータの吐出端面の低圧部側であってもよい。 The oil discharge destination of the oil discharge path may be on the low pressure part side of the discharge end face of the screw rotor.

この構成によれば、吐出端面部での空気漏れが減少し、スクリュ圧縮機の性能を向上できる。特に、吐出端面の低圧部側は、スクリュロータへの給油位置から離れている場合が多く、十分に油が供給されていない場合がある。従って、油が潤沢に存在しない吐出端面の低圧部側に排油を供給することで油によるシールを確実にできる。 According to this structure, the air leak in a discharge end surface part reduces, and the performance of a screw compressor can be improved. In particular, the low pressure part side of the discharge end face is often away from the oil supply position to the screw rotor, and there is a case where the oil is not sufficiently supplied. Therefore, oil can be reliably sealed by supplying waste oil to the low-pressure part side of the discharge end face where there is not enough oil.

前記排油経路の排油先は、前記スクリュロータの閉じ込み後の歯溝部であってもよい。 The oil drainage destination of the oil drainage path may be a tooth groove part after the screw rotor is closed.

吐出側軸受を潤滑及び冷却していない低温の油が閉じ込み後に戻ることで、油による空気の加熱が低減され、それによる動力の増加を防止できる。なお、仮に閉じ込み前に油を戻すと油が吸込空間に飛散し空気を加熱し空気が膨張し風量が低下するので、閉じ込み後の空間に戻すことでこれを防止している。 Since the low-temperature oil that has not lubricated and cooled the discharge-side bearing returns after being closed, the heating of air by the oil is reduced, thereby preventing an increase in power. If the oil is returned before being closed, the oil scatters into the suction space, heats the air, expands the air, and the air volume decreases. This is prevented by returning to the closed space.

前記油冷式スクリュ圧縮機は前記スクリュロータに油を給油するロータ給油口を備え、前記排油経路の排油先は前記ロータ給油口よりも前記スクリュロータの吸込端面側であってもよい。 The oil-cooled screw compressor may include a rotor oil supply port that supplies oil to the screw rotor, and the oil discharge destination of the oil discharge path may be closer to the suction end surface of the screw rotor than the rotor oil supply port.

ロータ給油口よりも吸込端面側の圧縮室は軸受室より低い圧力のため、ロータ給油口よりもスクリュロータの吸込端面側に排油先を設けることで、排油経路において高圧から低圧への流れが形成され、排油不良を防止できる。換言すると、排油先がロータ給油位置より吐出端面側の場合、排油先の圧力が軸受室の圧力に対して相対的に高くなり排油が困難になる。従って、本構成によってこのように排油が困難となることを防止している。 Since the compression chamber on the suction end face side of the rotor oil supply port is lower in pressure than the bearing chamber, by providing an oil discharge point on the suction end face side of the screw rotor from the rotor oil supply port, the flow from high pressure to low pressure in the oil discharge path Is formed, and oil discharge failure can be prevented. In other words, when the oil discharge destination is on the discharge end face side from the rotor oil supply position, the pressure of the oil discharge destination is relatively higher than the pressure in the bearing chamber, and oil discharge becomes difficult. Therefore, this configuration prevents the oil from becoming difficult in this way.

前記吐出側軸受は内輪及び外輪を備え、前記排油経路には前記吐出側軸受の前記内輪の下端と前記外輪の下端の間の高さに先端が位置するように堰が設けられ、前記堰の下流には油溜部が設けられ、前記油溜部の底には排油穴が設けられていることが好ましい。 The discharge side bearing includes an inner ring and an outer ring, and the drainage path is provided with a weir so that a tip is located at a height between a lower end of the inner ring and a lower end of the outer ring of the discharge side bearing, It is preferable that an oil reservoir is provided downstream of the oil reservoir, and an oil drain hole is provided at the bottom of the oil reservoir.

前記内輪と前記外輪の間の高さに設定された堰を設けることで、吐出側軸受の内輪と外輪の間に配置された転動体付近に油面位置を常に維持でき、油を過剰に排出することによる吐出側軸受の焼き付きを防止できる。また、油溜部を設けることで圧縮空気よりも油を優先的に排出できるため、空気の再圧縮による動力の増加を防止でき、性能を向上できる。 By providing a weir set at a height between the inner ring and the outer ring, the oil level position can always be maintained in the vicinity of the rolling elements arranged between the inner ring and the outer ring of the discharge side bearing, and excessive oil is discharged. By doing so, seizure of the discharge-side bearing can be prevented. Moreover, since oil can be discharged preferentially over compressed air by providing an oil reservoir, an increase in power due to recompression of air can be prevented, and performance can be improved.

本発明によれば、軸受における油の撹拌ロスを低減することにより油冷式スクリュ圧縮機の性能を向上できる。 According to the present invention, it is possible to improve the performance of the oil-cooled screw compressor by reducing the oil stirring loss in the bearing.

本発明の第１実施形態に係る油冷式スクリュ圧縮機の平面部分断面図。The plane partial sectional view of the oil-cooled screw compressor concerning a 1st embodiment of the present invention. 図１のII−II線に沿った部分断面図。FIG. 2 is a partial sectional view taken along line II-II in FIG. 1. 図１のIII−III線に沿った部分断面図。FIG. 3 is a partial sectional view taken along line III-III in FIG. 1. 図１のIV−IVに沿った部分断面図。The fragmentary sectional view in alignment with IV-IV of FIG. 図４のV−V線に沿った部分断面図。The fragmentary sectional view in alignment with the VV line of FIG. 本発明の第２実施形態に係る油冷式スクリュ圧縮機の平面部分断面図。The plane fragmentary sectional view of the oil-cooled screw compressor which concerns on 2nd Embodiment of this invention. 図６のVII−VIIに沿った部分断面図。The fragmentary sectional view in alignment with VII-VII of FIG.

以下、添付図面を参照して本発明の実施形態を説明する。 Embodiments of the present invention will be described below with reference to the accompanying drawings.

（第１実施形態）
図１から図４は、本発明の第１実施形態に係る油冷式スクリュ圧縮機２を示す図であり、それぞれ平面、側面、及び２つの正面の部分断面図を示している。 (First embodiment)
FIGS. 1 to 4 are views showing an oil-cooled screw compressor 2 according to a first embodiment of the present invention, and show a plane, a side surface, and two front sectional views.

図１から図３に示すように、本実施形態のスクリュ圧縮機２は、鋳物からなるケーシング４が形成する圧縮室６の中に、雌雄一対の互いに噛合する雄ロータ８（スクリュロータ）および雌ロータ９（スクリュロータ）を回転可能に収容している。雄ロータ８は、空気を圧縮する雄ロータ本体８ａと、雄ロータ本体８ａを支持する吸込側の軸８ｂ及び吐出側の軸８ｃとを備える。同様に、雌ロータ９は、雄ロータ本体８ａと噛合して空気を圧縮する雌ロータ本体９ａと、雌ロータ本体９ａを支持する吸込側の軸９ｂ及び吐出側の軸９ｃとを備える。 As shown in FIGS. 1 to 3, the screw compressor 2 of this embodiment includes a male and female pair of male and female rotors 8 (screw rotors) and females in a compression chamber 6 formed by a casing 4 made of a casting. A rotor 9 (screw rotor) is rotatably accommodated. The male rotor 8 includes a male rotor body 8a that compresses air, a suction-side shaft 8b that supports the male rotor body 8a, and a discharge-side shaft 8c. Similarly, the female rotor 9 includes a female rotor main body 9a that meshes with the male rotor main body 8a to compress air, and a suction-side shaft 9b and a discharge-side shaft 9c that support the female rotor main body 9a.

図１及び図２に示すように、ケーシング４内には、圧縮室６と共に軸受室１０が形成されている。吐出側の軸８ｃ，９ｃとケーシング４との間には、軸封装置（吐出側軸封）１４が配設されており、圧縮室６と軸受室１０との間を隔離している。 As shown in FIGS. 1 and 2, a bearing chamber 10 is formed in the casing 4 together with the compression chamber 6. A shaft seal device (discharge shaft seal) 14 is disposed between the discharge-side shafts 8 c and 9 c and the casing 4 to isolate the compression chamber 6 and the bearing chamber 10 from each other.

軸受室１０には、吐出側の軸８ｃ，９ｃを回転自在に支持する吐出側軸受１６が収容されている。図４に示すように、吐出側軸受１６は、リング状の内輪１８と外輪２０とその間に配置された球状の転動体２２とを備える。図１及び図２に示すように、吐出側軸受１６によって軸受室１０内が、軸受上流空間２４と軸受下流空間２６とに仕切られている。 The bearing chamber 10 accommodates a discharge-side bearing 16 that rotatably supports the discharge-side shafts 8c and 9c. As shown in FIG. 4, the discharge-side bearing 16 includes a ring-shaped inner ring 18, an outer ring 20, and a spherical rolling element 22 disposed therebetween. As shown in FIGS. 1 and 2, the inside of the bearing chamber 10 is partitioned by a discharge-side bearing 16 into a bearing upstream space 24 and a bearing downstream space 26.

図１に示すように、本実施形態のスクリュ圧縮機２は、雄ロータ８の吸込側の軸８ｂがケーシング４の外側に延伸し、不図示のモータ等に接続されている。従って、雄ロータ８の吸込側の軸８ｂがケーシング４を貫通する部分にも軸封装置（図示せず）が設けられている。一方、吐出側の軸８ｃ，９ｃの端部はケーシング４内に収容されている。吐出側の軸８ｃ，９ｃの端部には、スラスト荷重を受け止めるための軸受内輪抑え２８及び軸受外輪抑え３０が設けられている。軸受内輪抑え２８は吐出側軸受１６の内輪１８と当接し、軸受外輪抑え３０は吐出側軸受１６の外輪２０と当接し、内輪１８及び外輪２０の軸方向の移動をそれぞれ制限している。 As shown in FIG. 1, in the screw compressor 2 of the present embodiment, the suction-side shaft 8b of the male rotor 8 extends to the outside of the casing 4, and is connected to a motor (not shown) or the like. Therefore, a shaft seal device (not shown) is also provided at a portion where the suction-side shaft 8 b of the male rotor 8 passes through the casing 4. On the other hand, end portions of the discharge-side shafts 8 c and 9 c are accommodated in the casing 4. A bearing inner ring retainer 28 and a bearing outer ring retainer 30 for receiving a thrust load are provided at the ends of the discharge-side shafts 8c and 9c. The bearing inner ring restraint 28 is in contact with the inner ring 18 of the discharge side bearing 16, and the bearing outer ring restraint 30 is in contact with the outer ring 20 of the discharge side bearing 16, thereby restricting the axial movement of the inner ring 18 and the outer ring 20.

本発明と直接関係がないため図示及び説明を省略するが、吐出側だけでなく吸込側にも同様に吸込側の軸８ｂ，９ｂを支持する軸受等の機構が設けられている。 Although not shown or described because it is not directly related to the present invention, a mechanism such as a bearing for supporting the suction-side shafts 8b and 9b is provided not only on the discharge side but also on the suction side.

図２に示すように、ケーシング４の下方には、スクリュロータ８，９に油を供給するためのロータ給油口３２が設けられている。ロータ給油口３２は、ケーシング４を貫通して設けられており、雄ロータ本体８ａ及び雌ロータ本体９ａによって空気を閉じ込めて圧縮した後の圧縮室６内の下側（高圧側）部分と連通している。ロータ給油口３２を通じて供給される油により、圧縮途中の空気を冷却すると共に隙間をシールし、圧縮性能を向上させている。 As shown in FIG. 2, a rotor oil supply port 32 for supplying oil to the screw rotors 8 and 9 is provided below the casing 4. The rotor refueling port 32 is provided through the casing 4 and communicates with a lower (high pressure side) portion in the compression chamber 6 after the air is trapped and compressed by the male rotor main body 8a and the female rotor main body 9a. ing. The oil supplied through the rotor oil supply port 32 cools the air in the middle of compression and seals the gap to improve the compression performance.

また、ケーシング４には、軸封給油口３４が設けられている。軸封給油口３４は、ロータ給油口３２と同様にケーシング４を貫通して設けられている。軸封給油口３４は、吐出側軸受１６に油を供給するため軸受上流空間２４と連通している。軸封給油口３４を通じて吐出側軸受１６に油が供給されることで吐出側軸受１６を冷却すると共に潤滑し、摩擦によるエネルギー損失を防止している。 Further, the casing 4 is provided with a shaft seal oil supply port 34. The shaft seal oil filler 34 is provided through the casing 4 in the same manner as the rotor oil filler 32. The shaft sealing oil supply port 34 communicates with the bearing upstream space 24 to supply oil to the discharge-side bearing 16. By supplying oil to the discharge-side bearing 16 through the shaft seal oil supply port 34, the discharge-side bearing 16 is cooled and lubricated to prevent energy loss due to friction.

図１及び図２に破線で示すように、本実施形態のスクリュ圧縮機２は、軸受上流空間２４に溜まった油を排油するため、一端が軸受上流空間２４に連通した排油経路４４を備える。排油経路４４の他端は圧縮室６の雄ロータ本体８ａと雌ロータ本体９ａの吐出端面８ｄ，９ｄの低圧部側に連通しており、軸受上流空間２４から排油された油は雄ロータ本体８ａと雌ロータ本体９ａに供給される。吐出端面８ｄ，９ｄとは、雄ロータ本体８ａと雌ロータ本体９ａの吐出側に設けられた端面である。吐出端面８ｄ，９ｄにおいて、雄ロータ本体８ａ及び雌ロータ本体９ａは、吐出側の軸８ｃ，９ｃとそれぞれ接続されている。また、低圧部側とは、スクリュロータ８，９において空気を閉じ込み圧縮する前の低圧状態である側を示し、図２において一点鎖線で示すスクリュロータ８，９の軸線Ｌよりも上側に概略一致する。 As shown by broken lines in FIGS. 1 and 2, the screw compressor 2 of the present embodiment drains the oil accumulated in the bearing upstream space 24, and therefore has an oil drain path 44 with one end communicating with the bearing upstream space 24. Prepare. The other end of the oil discharge path 44 communicates with the male rotor main body 8a of the compression chamber 6 and the low pressure portion side of the discharge end faces 8d and 9d of the female rotor main body 9a, and the oil discharged from the bearing upstream space 24 is the male rotor. It is supplied to the main body 8a and the female rotor main body 9a. The discharge end faces 8d and 9d are end faces provided on the discharge side of the male rotor main body 8a and the female rotor main body 9a. On the discharge end faces 8d and 9d, the male rotor main body 8a and the female rotor main body 9a are connected to the discharge-side shafts 8c and 9c, respectively. Further, the low pressure part side means a side in a low pressure state before the air is closed and compressed in the screw rotors 8 and 9, and is roughly above the axis L of the screw rotors 8 and 9 indicated by a one-dot chain line in FIG. Match.

吐出側軸受１６と軸封装置１４との間の軸受上流空間２４に対して排油経路４４を設けたことで、吐出側軸受１６の上流側の軸受上流空間２４に溜まる余分な油を排油できる。従って、吐出側軸受１６の上流側に必要以上に油が溜まることを防止でき、吐出側軸受１６における油の撹拌ロスを低減できる。 By providing the oil drainage path 44 to the bearing upstream space 24 between the discharge side bearing 16 and the shaft seal device 14, excess oil accumulated in the bearing upstream space 24 on the upstream side of the discharge side bearing 16 is drained. it can. Therefore, it is possible to prevent the oil from being accumulated more than necessary on the upstream side of the discharge side bearing 16 and reduce the oil stirring loss in the discharge side bearing 16.

また、吐出端面８ｄ，９ｄの低圧部側に排油することで吐出端面８ｄ，９ｄ付近での空気漏れが減少し、スクリュ圧縮機２の性能を向上できる。特に、吐出端面８ｄ，９ｄの低圧部側は、ロータ給油口３２から離れている場合が多く、十分に油が供給されていない。従って、油が潤沢に存在しない吐出端面８ｄ，９ｄの低圧部側に排油を供給することで油によるシールを確実にできる。 Further, by draining oil to the low pressure part side of the discharge end faces 8d and 9d, air leakage near the discharge end faces 8d and 9d is reduced, and the performance of the screw compressor 2 can be improved. In particular, the low pressure part side of the discharge end faces 8d and 9d is often away from the rotor oil supply port 32, and the oil is not sufficiently supplied. Therefore, oil can be reliably sealed by supplying waste oil to the low pressure portion side of the discharge end faces 8d and 9d where there is not abundant oil.

図４に示すように、排油経路４４には、油の流動を妨げる堰３６が設けられている。図５を合わせて参照すると、堰３６は排油経路４４の底部から上向きかつ排油経路４４の両側にわたって延びている。また、図４に示すように、堰３６の先端３６ａは吐出側軸受１６の内輪１８の下端１８ａと外輪２０の下端２０ａの間の高さに位置するように設けられている。また、堰３６の下流には油を一時的に貯留する油溜部３８が設けられている。油溜部３８の底には排油穴４０が設けられている。 As shown in FIG. 4, the drainage passage 44 is provided with a weir 36 that prevents the oil from flowing. Referring also to FIG. 5, the weir 36 extends upward from the bottom of the oil discharge passage 44 and extends on both sides of the oil discharge passage 44. As shown in FIG. 4, the tip 36 a of the weir 36 is provided so as to be positioned between the lower end 18 a of the inner ring 18 and the lower end 20 a of the outer ring 20 of the discharge side bearing 16. An oil reservoir 38 that temporarily stores oil is provided downstream of the weir 36. An oil drain hole 40 is provided at the bottom of the oil reservoir 38.

内輪１８と外輪２０の間の高さに設定された堰３６を設けることで、吐出側軸受１６の内輪１８と外輪２０の間に配置された転動体２２付近に油面位置を常に維持でき、油を過剰に排出することによる吐出側軸受１６の焼き付きを防止できる。また、油溜部３８を設けることで圧縮空気よりも油を優先的に排出できるため、空気の再圧縮による動力の増加を防止でき、性能を向上できる。 By providing the weir 36 set at a height between the inner ring 18 and the outer ring 20, the oil surface position can always be maintained in the vicinity of the rolling elements 22 disposed between the inner ring 18 and the outer ring 20 of the discharge-side bearing 16, It is possible to prevent seizure of the discharge-side bearing 16 due to excessive discharge of oil. Moreover, since oil can be discharged preferentially over compressed air by providing the oil reservoir 38, an increase in power due to recompression of air can be prevented, and performance can be improved.

さらに、図１及び図２に破線で示すように、本実施形態のスクリュ圧縮機２は、軸受上流空間２４に溜まった油を排油するため、一端が軸受下流空間２６に連通した排油経路４６を備える。排油経路４６の他端は圧縮室６の雄ロータ本体８ａと雌ロータ本体９ａの閉じ込み後の歯溝部８ｅ，９ｅに連通しており、軸受下流空間２６から排油された油は雄ロータ本体８ａと雌ロータ本体９ａの歯溝部８ｅ，９ｅに供給される。閉じ込み後とは、図２において二点鎖線で示す閉じ込み線よりも吐出側のスクリュロータ８，９により空気が圧縮される範囲のことを示す。ここで、閉じ込み線とは、スクリュロータ８，９の最外径のシールエッジとケーシング４の内面とで、圧縮空間と吸込空間４８とが切り離され、空気の圧縮が開始されるシールエッジの位置を示している。この閉じ込み線において雄ロータ本体８ａおよび雌ロータ本体９ａは噛合し、これより下流で空気を閉じ込めて圧縮している。従って、閉じ込み後は閉じ込み前より高圧となっている。ここで、排油経路４６からの排油先である閉じ込み後の歯溝部８ｅ，９ｅは、閉じ込み直後の歯溝部８ｅ，９ｅであることが好ましい。即ち、雄ロータ本体８ａおよび雌ロータ本体９ａが互いに噛合した直後の歯溝部８ｅ，９ｅであることが好ましい。閉じ込み直後の歯溝圧力は非常に低いため、排油先が軸受室１０に対して相対的に低圧となり、油の排油不良を防止できるためである。 Further, as indicated by broken lines in FIGS. 1 and 2, the screw compressor 2 of the present embodiment drains the oil accumulated in the bearing upstream space 24, so that one end of the screw compressor 2 communicates with the bearing downstream space 26. 46. The other end of the oil discharge passage 46 communicates with the male rotor main body 8a of the compression chamber 6 and the tooth groove portions 8e and 9e after the female rotor main body 9a is closed, and the oil discharged from the bearing downstream space 26 is the male rotor. It is supplied to the tooth groove portions 8e and 9e of the main body 8a and the female rotor main body 9a. “After confinement” means a range in which air is compressed by the screw rotors 8 and 9 on the discharge side with respect to the confinement line indicated by a two-dot chain line in FIG. Here, the closed line is the seal edge of the outermost diameter of the screw rotors 8 and 9 and the inner surface of the casing 4, and the compression space and the suction space 48 are separated from each other and the compression of air is started. Indicates the position. The male rotor main body 8a and the female rotor main body 9a mesh with each other at this confinement line, and the air is confined and compressed downstream from this. Therefore, after closing, the pressure is higher than before closing. Here, it is preferable that the tooth groove portions 8e and 9e after closing, which are oil discharge destinations from the oil discharge passage 46, are tooth groove portions 8e and 9e immediately after closing. That is, the tooth groove portions 8e and 9e immediately after the male rotor main body 8a and the female rotor main body 9a are engaged with each other are preferable. This is because the tooth gap pressure immediately after closing is very low, so that the oil drainage point is relatively low with respect to the bearing chamber 10 and oil drainage failure can be prevented.

さらに図２に示すように、排油経路４６の排油先は、ロータ給油口３２よりも雄ロータ本体８ａと雌ロータ本体９ａの吸込端面８ｆ，９ｆ側（図において右側）に設けられている。吸込端面８ｆ，９ｆとは、雄ロータ本体８ａと雌ロータ本体９ａの吸込側に設けられた端面である。吸込端面８ｆ，９ｆにおいて、雄ロータ本体８ａ及び雌ロータ本体９ａは、吸込側の軸８ｂ，９ｂとそれぞれ接続されている。また、排油先は雄ロータ本体８ａと雌ロータ本体９ａの閉じ込み後の圧縮室６内である。仮に、雄ロータ本体８ａと雌ロータ本体９ａの閉じ込み前の圧縮室６内に油を戻すと、油が吸込空間４８に飛散し空気を加熱し空気が膨張し風量が低下するので、閉じ込み後の空間に戻すことでこれを防止している。 Further, as shown in FIG. 2, the oil discharge destination of the oil discharge passage 46 is provided on the suction end faces 8 f and 9 f side (right side in the drawing) of the male rotor main body 8 a and the female rotor main body 9 a from the rotor oil supply port 32. . The suction end faces 8f and 9f are end faces provided on the suction side of the male rotor main body 8a and the female rotor main body 9a. On the suction end faces 8f and 9f, the male rotor body 8a and the female rotor body 9a are connected to the suction-side shafts 8b and 9b, respectively. The oil drainage destination is in the compression chamber 6 after the male rotor body 8a and the female rotor body 9a are closed. If the oil is returned to the compression chamber 6 before the male rotor main body 8a and the female rotor main body 9a are closed, the oil scatters into the suction space 48, heats the air, expands the air, and the air volume decreases. This is prevented by returning to a later space.

ロータ給油口３２よりも吸込端面８ｆ，９ｆ側の圧縮室６は軸受室１０より低い圧力のため、ロータ給油口３２よりも吸込端面８ｆ，９ｆ側に排油先を設けることで、排油経路４６において高圧から低圧への流れが形成され、排油不良を防止できる。換言すると、仮に排油先がロータ給油口３２の位置より吐出端面８ｄ，９ｄ側の場合、排油先の圧力が高くなり排油が困難になる。従って、本構成によってこのように軸受下流空間２６からの排油が困難となることを防止している。 Since the compression chamber 6 on the suction end surfaces 8f, 9f side of the rotor oil supply port 32 has a lower pressure than the bearing chamber 10, an oil discharge path is provided by providing an oil discharge destination on the suction end surfaces 8f, 9f side of the rotor oil supply port 32. In 46, a flow from a high pressure to a low pressure is formed, and oil discharge failure can be prevented. In other words, if the oil discharge destination is on the discharge end face 8d, 9d side from the position of the rotor oil supply port 32, the pressure of the oil discharge destination becomes high and oil discharge becomes difficult. Therefore, this configuration prevents the oil from the bearing downstream space 26 from becoming difficult in this way.

（第２実施形態）
図６及び図７は、本発明の第２実施形態に係るスクリュ圧縮機２の平面および側面の部分断面図を示している。本実施形態のスクリュ圧縮機２は、排油経路４４，４６に関する部分以外の構成は図１から図５に示した第１実施形態と実質的に同様である。従って、図１から図５に示した構成と同様の部分については説明を省略する場合がある。特に、本実施形態のスクリュ圧縮機２の正面図は、図４に示す第１実施形態と同じである。 (Second Embodiment)
6 and 7 show a partial cross-sectional view of the plane and side surfaces of the screw compressor 2 according to the second embodiment of the present invention. The screw compressor 2 of the present embodiment is substantially the same as the first embodiment shown in FIGS. 1 to 5 except for the portions related to the oil discharge paths 44 and 46. Therefore, description of the same parts as those shown in FIGS. 1 to 5 may be omitted. In particular, the front view of the screw compressor 2 of the present embodiment is the same as that of the first embodiment shown in FIG.

図６及び図７に示すように、本実施形態のスクリュ圧縮機２は、軸受上流空間２４から排油するための排油経路４４の排油先が雄ロータ本体８ａと雌ロータ本体９ａの閉じ込み後の歯溝部８ｅ，９ｅである。さらに、軸受上流空間２４から排油するための排油経路４４と軸受下流空間２６から排油するための排油経路４６は、経路途中で互いに合流し、排油先を共通している。 As shown in FIGS. 6 and 7, in the screw compressor 2 of the present embodiment, the oil discharge destination of the oil discharge path 44 for discharging oil from the bearing upstream space 24 is closed between the male rotor body 8a and the female rotor body 9a. It is the tooth gap part 8e and 9e after insertion. Further, the oil drain path 44 for draining oil from the bearing upstream space 24 and the oil drain path 46 for draining oil from the bearing downstream space 26 merge with each other in the middle of the path, and share the oil drain destination.

従って、その排油先は、第１実施形態と同様に、閉じ込み後の歯溝部８ｅ，９ｅは、閉じ込み直後の歯溝部８ｅ，９ｅであることが好ましく、即ち図７において二点鎖線で示す閉じ込み線よりも吐出側の近傍であることが好ましい。 Accordingly, the oil drainage destination is preferably the tooth groove portions 8e, 9e after the closing, as in the first embodiment, that is, the tooth groove portions 8e, 9e immediately after the closing, that is, in FIG. It is preferable that the area is closer to the discharge side than the confinement line shown.

さらに図７に示すように、排油経路４４，４６の排油先は、ロータ給油口３２よりも吸込端面８ｆ、９ｆ側（図において右側）に設けられている。 Further, as shown in FIG. 7, the oil discharge destinations of the oil discharge passages 44 and 46 are provided closer to the suction end surfaces 8 f and 9 f (right side in the drawing) than the rotor oil supply port 32.

吐出側軸受１６を潤滑及び冷却していない低温の油が閉じ込み後に戻ることで、油による空気の加熱が低減され、それによる動力の増加を防止できる。 Since the low-temperature oil that has not lubricated and cooled the discharge-side bearing 16 returns after being closed, heating of air by the oil is reduced, and an increase in power due to this can be prevented.

第１実施形態と同様に、ロータ給油口３２よりも吸込端面８ｆ側の圧縮室６は軸受室１０より低い圧力のため、ロータ給油口３２よりも吸込端面８ｆ，９ｆ側に排油先を設けることで、排油経路において高圧から低圧への流れが形成され、排油不良を防止できる。換言すると、排油先がロータ給油口３２の位置より吐出端面８ｄ，９ｄ側の場合、排油先の圧力が高くなり排油が困難になる。従って、本構成によってこのように軸受上流空間２４及び軸受下流空間２６からの排油が困難となることを防止している。 As in the first embodiment, the compression chamber 6 on the suction end surface 8f side of the rotor oil supply port 32 has a pressure lower than that of the bearing chamber 10, so that an oil discharge destination is provided on the suction end surfaces 8f and 9f side of the rotor oil supply port 32. As a result, a flow from high pressure to low pressure is formed in the oil discharge path, and poor oil discharge can be prevented. In other words, when the oil discharge destination is on the discharge end face 8d, 9d side from the position of the rotor oil supply port 32, the pressure of the oil discharge destination becomes high and oil discharge becomes difficult. Therefore, this configuration prevents oil from being discharged from the bearing upstream space 24 and the bearing downstream space 26 in this way.

２（油冷式）スクリュ圧縮機
４ケーシング
６圧縮室
８雄ロータ（スクリュロータ）
８ａ雄ロータ本体
８ｂ吸込側の軸
８ｃ吐出側の軸
８ｄ吐出端面
８ｅ歯溝部
８ｆ吸込端面
９雌ロータ（スクリュロータ）
９ａ雌ロータ本体
９ｂ吸込側の軸
９ｃ吐出側の軸
９ｄ吐出端面
９ｅ歯溝部
９ｆ吸込端面
１０軸受室
１４軸封装置（吐出側軸封）
１６吐出側軸受
１８内輪
１８ａ下端
２０外輪
２０ａ下端
２２転動体
２４軸受上流空間
２６軸受下流空間
２８軸受内輪抑え
３０軸受外輪抑え
３２ロータ給油口
３４軸封給油口
３６堰
３６ａ先端
３８油溜部
４０排油穴
４４，４６排油経路
４８吸込空間 2 (oil-cooled) screw compressor 4 casing 6 compression chamber 8 male rotor (screw rotor)
8a Male rotor body 8b Suction-side shaft 8c Discharge-side shaft 8d Discharge end surface 8e Tooth groove 8f Suction end surface 9 Female rotor (screw rotor)
9a Female rotor body 9b Suction-side shaft 9c Discharge-side shaft 9d Discharge end surface 9e Tooth groove 9f Suction end surface 10 Bearing chamber 14 Shaft seal device (discharge-side shaft seal)
16 Discharge side bearing 18 Inner ring 18a Lower end 20 Outer ring 20a Lower end 22 Rolling element 24 Bearing upstream space 26 Bearing downstream space 28 Bearing inner ring restraint 30 Bearing outer ring restraint 32 Rotor oil supply port 34 Shaft seal oil supply port 36 Dam 36a tip 38 Oil reservoir 40 Drainage Oil hole 44, 46 Oil drainage path 48 Suction space

Claims

圧縮室と軸受室が内部に設けられたケーシングと、
前記圧縮室に配置された互いに噛合する一対のスクリュロータと、
前記軸受室に配置された前記スクリュロータの吐出側端部を回転自在に支持する吐出側軸受と、
前記圧縮室と前記軸受室とを隔離する吐出側軸封と、
前記吐出側軸受と前記吐出側軸封との間に設けられた前記軸受室から排油する排油経路と
を備える油冷式スクリュ圧縮機。 A casing in which a compression chamber and a bearing chamber are provided;
A pair of screw rotors arranged in the compression chamber and meshing with each other;
A discharge-side bearing that rotatably supports a discharge-side end portion of the screw rotor disposed in the bearing chamber;
A discharge side shaft seal separating the compression chamber and the bearing chamber;
An oil-cooled screw compressor comprising: an oil discharge path for discharging oil from the bearing chamber provided between the discharge side bearing and the discharge side shaft seal.

前記排油経路の排油先は、前記スクリュロータの吐出端面の低圧部側である、請求項１に記載の油冷式スクリュ圧縮機。 2. The oil-cooled screw compressor according to claim 1, wherein an oil discharge destination of the oil discharge path is on a low pressure portion side of a discharge end surface of the screw rotor.

前記排油経路の排油先は、前記スクリュロータの閉じ込み後の歯溝部である、請求項１に記載の油冷式スクリュ圧縮機。 2. The oil-cooled screw compressor according to claim 1, wherein an oil discharge destination of the oil discharge path is a tooth groove portion after the screw rotor is closed.

前記スクリュロータに油を給油するロータ給油口を備え、
前記排油経路の排油先は、前記ロータ給油口よりも前記スクリュロータの吸込端面側である、請求項１又は請求項３に記載の油冷式スクリュ圧縮機。 A rotor oil supply port for supplying oil to the screw rotor;
4. The oil-cooled screw compressor according to claim 1, wherein an oil discharge destination of the oil discharge path is closer to a suction end face of the screw rotor than the rotor oil supply port.

前記吐出側軸受は内輪及び外輪を備え、
前記排油経路には前記吐出側軸受の前記内輪の下端と前記外輪の下端の間の高さに先端が位置するように堰が設けられ、前記堰の下流には油溜部が設けられ、前記油溜部の底には排油穴が設けられている、請求項１から請求項４のいずれか１項に記載の油冷式スクリュ圧縮機。 The discharge side bearing includes an inner ring and an outer ring,
The drainage path is provided with a weir so that the tip is positioned at a height between the lower end of the inner ring and the lower end of the outer ring of the discharge side bearing, and an oil reservoir is provided downstream of the weir, The oil-cooled screw compressor according to any one of claims 1 to 4, wherein an oil drain hole is provided in a bottom of the oil reservoir.