JP2022104058A - Shaft seal structure of oil-cooled screw compressor - Google Patents

Abstract

To provide a shaft seal structure of an oil-cooled screw compressor capable of reducing an oil supply amount to a shaft seal portion while preventing leakage of a compressed gas from a rotor chamber.SOLUTION: A cylindrical spacer 36 for shaft sealing is externally fitted to a discharge-side rotor shaft 42 between a bearing chamber 32 and a rotor chamber 11. An endless annular oil supply groove 37 is formed on an outer peripheral surface of the spacer 36 to communicate with an oil supply flow channel 93, and a clearance Δ is sealed by oil supply to the oil supply groove 37 so as to prevent leakage of a compressed gas from the rotor chamber 11. By forming a labyrinth groove 38 having a cross-sectional shape gradually enlarged from the bearing chamber 32 side toward the rotor chamber 11 side on an outer peripheral surface of the spacer 36 at the rotor chamber 11 side with respect to the oil supply groove 37, leakage of the compressed gas from the rotor chamber 11 can be prevented even when a pressure of a lubricant of the oil supply groove 37 is lowered by reducing an oil supply amount to the oil supply groove 37.SELECTED DRAWING: Figure 3

Description

本発明は油冷式スクリュ圧縮機の軸封構造に関し，より詳細には，油冷式スクリュ圧縮機のスクリュロータに設けた吐出側ロータ軸と軸孔間の間隔を介してロータ室の圧縮気体が漏出することを防止するための軸封部の構造に関する。 The present invention relates to a shaft sealing structure of an oil-cooled screw compressor, and more specifically, a compressed gas in a rotor chamber is provided through a gap between a discharge side rotor shaft and a shaft hole provided in a screw rotor of an oil-cooled screw compressor. Regarding the structure of the shaft seal part to prevent leakage.

油冷式スクリュ圧縮機１００は，ケーシング内に形成されたロータ室１１１内にオス，メス一対のスクリュロータ１４０，１５０を噛み合い回転可能に収容し，前記一対のスクリュロータ１４０，１５０の噛み合い回転により被圧縮気体を潤滑油と共に圧縮して気液混合流体として吐出するもので，各種の気体の圧縮に使用されている。 The oil-cooled screw compressor 100 meshes and rotatably accommodates a pair of male and female screw rotors 140 and 150 in a rotor chamber 111 formed in a casing, and the pair of screw rotors 140 and 150 mesh with each other to rotate. It compresses the gas to be compressed together with the lubricating oil and discharges it as a gas-liquid mixed fluid, and is used for compressing various gases.

この油冷式スクリュ圧縮機１００は，前述のように被圧縮気体を潤滑油と共に圧縮して気液混合流体として吐出するものであることから，空気作業機等が接続された消費側に対し圧縮気体を供給するためには，油冷式スクリュ圧縮機１００が吐出した気液混合流体から潤滑油を除去する必要がある。 Since the oil-cooled screw compressor 100 compresses the gas to be compressed together with the lubricating oil and discharges it as a gas-liquid mixed fluid as described above, it is compressed with respect to the consumption side to which the air working machine or the like is connected. In order to supply the gas, it is necessary to remove the lubricating oil from the gas-liquid mixed fluid discharged by the oil-cooled screw compressor 100.

そのため，図６に示すように，エンジンやモータなどの駆動源２１０によって駆動することにより油冷式スクリュ圧縮機１００が吐出した気液混合流体は，一旦，レシーバタンク２２０内に導入して気液分離した後，潤滑油が分離された後の圧縮気体を，逆止弁２２１を介して消費側に供給する構成が採用されている。 Therefore, as shown in FIG. 6, the gas-liquid mixed fluid discharged by the oil-cooled screw compressor 100 driven by the drive source 210 such as an engine or a motor is once introduced into the receiver tank 220 and the gas-liquid. After separation, a configuration is adopted in which the compressed gas after the lubricating oil is separated is supplied to the consumption side via the check valve 221.

一方，レシーバタンク２２０内に回収された潤滑油はレシーバタンク２２０内の圧力を利用してオイルフィルタ２２２，オイルクーラ２２３を備える給油配管２２４を介して，再度，圧縮機本体に給油する構成が採用されている。 On the other hand, the lubricating oil collected in the receiver tank 220 is refueled to the compressor body via the oil filter 222 and the oil supply pipe 224 provided with the oil cooler 223 using the pressure in the receiver tank 220. Has been done.

このようにして油冷式スクリュ圧縮機１００に給油された潤滑油は，圧縮作用空間内に給油されて，圧縮作用空間の潤滑，冷却，及び密封のために使用される他，軸封部や軸受，歯車機構等の，油冷式スクリュ圧縮機１００内の潤滑が必要とされる部分に給油されて各部の潤滑や密封に使用されている。 The lubricating oil supplied to the oil-cooled screw compressor 100 in this way is supplied into the compression action space and used for lubrication, cooling, and sealing of the compression action space, as well as a shaft seal and a shaft seal. Lubrication is supplied to parts of the oil-cooled screw compressor 100 that require lubrication, such as bearings and gear mechanisms, and is used for lubrication and sealing of each part.

この油冷式スクリュ圧縮機１００では，スクリュロータ１４０，１５０をロータ室１１１内で噛み合い回転することができるようにするために，スクリュロータ１４０，１５０の両端にはロータ軸１４１，１４２（１５１，１５２）が形成されていると共に，ケーシング内に形成された軸孔内にロータ軸を挿入して，この軸孔と連通する軸受室１３２に収容した軸受１７０で各ロータ軸１４１，１４２（１５１，１５２）を回転可能に支承している。 In this oil-cooled screw compressor 100, in order to allow the screw rotors 140 and 150 to mesh and rotate in the rotor chamber 111, rotor shafts 141 and 142 (151, 142) at both ends of the screw rotors 140 and 150. 152) is formed, and the rotor shaft is inserted into the shaft hole formed in the casing, and each rotor shaft 141, 142 (151, 142) is accommodated in the bearing chamber 132 communicating with the shaft hole. 152) is rotatably supported.

そして，スクリュロータ１４０（１５０）の噛み合い回転によってロータ室１１１内で圧縮された圧縮気体が，スクリュロータ１４０（１５０）の吐出側ロータ軸１４２（１５２）の外周面と軸孔１３１の内周面間の間隔から漏出することを防止するために，吐出側ロータ軸１４２（１５２）を支承する軸受１７０を収容する軸受室１３２と，ロータ室１１１間には，前述した軸封部１３４が設けられている。 Then, the compressed gas compressed in the rotor chamber 111 by the meshing rotation of the screw rotor 140 (150) is the outer peripheral surface of the discharge side rotor shaft 142 (152) of the screw rotor 140 (150) and the inner peripheral surface of the shaft hole 131. In order to prevent leakage from the space between the bearing chambers 132 and the bearing chamber 132 that accommodates the bearing 170 that supports the discharge side rotor shaft 142 (152), the shaft sealing portion 134 described above is provided between the bearing chambers 111. ing.

この軸封部１３４の構成として，後掲の特許文献１では，図７に示すように吐出側の軸受１７０を収容する軸受室１３２とロータ室１１１間の吐出側ロータ軸１４２（１５２）の外周面に，周方向に連続して形成された無端環状の給油溝１３７を設けている。 As a configuration of the shaft sealing portion 134, in Patent Document 1 described later, as shown in FIG. 7, the outer periphery of the discharge side rotor shaft 142 (152) between the bearing chamber 132 accommodating the discharge side bearing 170 and the rotor chamber 111. An endless annular refueling groove 137 formed continuously in the circumferential direction is provided on the surface.

そして，この給油溝１３７に，前述したレシーバタンク２２０からの潤滑油を，給油配管２２４，及び，給油流路１９３を介して給油することで，この潤滑油によってロータ軸１４２の外周面と軸孔１３１の内周面間の隙間Δ’を封止し，この隙間Δ’を介してロータ室１１１より圧縮気体が漏出することを防止している。 Then, the lubricating oil from the receiver tank 220 described above is supplied to the lubrication groove 137 via the lubrication pipes 224 and the lubrication flow path 193, and the lubricating oil is used to supply the outer peripheral surface and the shaft hole of the rotor shaft 142. The gap Δ'between the inner peripheral surfaces of the 131 is sealed, and the compressed gas is prevented from leaking from the rotor chamber 111 through the gap Δ'.

そして，給油溝１３７を介してロータ軸１４２の外周面と軸孔１３１の内周面間の隙間Δ’に導入した潤滑油を軸受室１３２側に漏出させることで，軸受１７０に対する給油についても行うことができるように構成されている。 Then, the lubricating oil introduced into the gap Δ'between the outer peripheral surface of the rotor shaft 142 and the inner peripheral surface of the shaft hole 131 is leaked to the bearing chamber 132 side through the lubrication groove 137, so that the bearing 170 is also lubricated. It is configured to be able to.

特開２０１５－４３０６号公報JP-A-2015-4306

以上で説明した特許文献１に記載の軸封部１３４では，前述の隙間Δ’を介してロータ室１１１の圧縮気体が軸受室１３２へ漏出しないように油冷式スクリュ圧縮機の吐出圧と略同圧の潤滑油をロータ軸１４２（１５２）の外周面に設けた給油溝１３７に給油することで，この潤滑油の圧力と，ロータ室１１１より漏出しようとする圧縮気体の圧力が前述の隙間Δ’内で釣り合って，ロータ室１１１内の圧縮気体が隙間Δ’を通過することを防止する。 In the shaft sealing portion 134 described in Patent Document 1 described above, the discharge pressure of the oil-cooled screw compressor is abbreviated so that the compressed gas in the rotor chamber 111 does not leak to the bearing chamber 132 through the above-mentioned gap Δ'. By supplying lubricating oil of the same pressure to the lubrication groove 137 provided on the outer peripheral surface of the rotor shaft 142 (152), the pressure of this lubricating oil and the pressure of the compressed gas that is about to leak from the rotor chamber 111 are the above-mentioned gaps. It balances within Δ'and prevents the compressed gas in the rotor chamber 111 from passing through the gap Δ'.

ロータ軸１４２（１５２）の給油溝１３７に対して給油する潤滑油は，前述したように油冷式スクリュ圧縮機１００の吐出圧と略同圧であるため，高圧設定の油冷式スクリュ圧縮機１００のようにロータ室１１１内で圧縮された圧縮気体の圧力が高くなると，ロータ軸１４２（１５２）の給油溝１３７に対する給油圧力もこれに応じて高くなる。 Since the lubricating oil supplied to the oil supply groove 137 of the rotor shaft 142 (152) has substantially the same pressure as the discharge pressure of the oil-cooled screw compressor 100 as described above, the oil-cooled screw compressor with a high pressure setting When the pressure of the compressed gas compressed in the rotor chamber 111 increases as in 100, the oil supply pressure for the oil supply groove 137 of the rotor shaft 142 (152) also increases accordingly.

その結果，給油溝１３７に対する給油圧力の上昇分，給油溝１３７に対し軸受室１３２側のロータ軸１４２の外周面と軸孔１３１の内周面間の隙間Δ’を介して軸受１７０側に流入する潤滑油量，従って，軸受１７０に対する給油量が必要以上に増大する。 As a result, the amount of increase in the lubrication pressure with respect to the lubrication groove 137 flows into the bearing 170 side through the gap Δ'between the outer peripheral surface of the rotor shaft 142 on the bearing chamber 132 side and the inner peripheral surface of the shaft hole 131 with respect to the lubrication groove 137. The amount of lubricating oil to be applied, and therefore the amount of lubrication to the bearing 170, increases more than necessary.

このように，軸受１７０に対し必要量以上の潤滑油が給油されれば，軸受１７０が潤滑油を攪拌することに伴って生じる回転抵抗が増加することで油冷式スクリュ圧縮機１００の動力ロスが増加する。 In this way, if a required amount or more of lubricating oil is supplied to the bearing 170, the rotational resistance generated by the bearing 170 stirring the lubricating oil increases, resulting in a power loss of the oil-cooled screw compressor 100. Will increase.

また，軸受１７０を潤滑した後の潤滑油は，軸受１７０に対し機外側に設けられた潤滑油回収室１３５内に回収されるが，この潤滑油回収室１３５に回収された潤滑油を，潤滑油回収室１３５よりも低圧である吸気閉じ込み直後の圧縮作用空間に給油して回収する構成を採用する場合，圧縮作用空間に導入される潤滑油量も増加することとなるために，スクリュロータ１４０（１５０）がこのような増加分の潤滑油を攪拌することによって生じる動力ロスも大きくなる。 Further, the lubricating oil after lubricating the bearing 170 is recovered in the lubricating oil recovery chamber 135 provided on the outside of the machine with respect to the bearing 170, and the lubricating oil recovered in the lubricating oil recovery chamber 135 is lubricated. If a configuration is adopted in which oil is supplied and recovered in the compression action space immediately after the intake air is closed, which is lower than the oil recovery chamber 135, the amount of lubricating oil introduced into the compression action space also increases, so the screw rotor The power loss caused by the 140 (150) stirring such an increased amount of lubricating oil also increases.

このように，軸受１７０に対し過剰に給油が行われることを防止する方法としては，一例として図８に示すように，軸受室１３２とロータ室１１１間のロータ軸１４２に円筒状のスペーサ１３６を取り付け，このスペーサ１３６の外周面に前述の給油溝１３７を設けると共に，この給油溝１３７に対しロータ室１１１側のスペーサ１３６の外周面と，軸受室１３２側のスペーサ１３６の外周面に，断面矩形状を有し，周方向に連続して形成された無端環状のラビリンス溝１３８’，１３９を複数形成することで，このスペーサ１３６にラビリンスシールとしての機能を持たせることも考えられる。 As a method for preventing excessive lubrication of the bearing 170 in this way, as shown in FIG. 8 as an example, a cylindrical spacer 136 is provided on the rotor shaft 142 between the bearing chamber 132 and the rotor chamber 111. The above-mentioned oil supply groove 137 is provided on the outer peripheral surface of the spacer 136, and the outer peripheral surface of the spacer 136 on the rotor chamber 111 side and the outer peripheral surface of the spacer 136 on the bearing chamber 132 side with respect to the oil supply groove 137 have a rectangular cross section. It is also conceivable to give the spacer 136 a function as a labyrinth seal by forming a plurality of endless annular labyrinth grooves 138'and 139 having a shape and continuously formed in the circumferential direction.

この構成では，給油溝１３７から軸受室１３２側に向かってスペーサ１３６の外周面と軸孔１３１の内周面間の隙間Δを通過する潤滑油は，図８（Ｂ）に示すようにラビリンス溝１３９間に形成された絞り部と，ラビリンス溝１３９内に形成された拡大部を交互に通過することにより生じる圧力損失によって，軸受１７０側に流入する潤滑油の量を減少させることが可能となる。 In this configuration, the lubricating oil that passes through the gap Δ between the outer peripheral surface of the spacer 136 and the inner peripheral surface of the shaft hole 131 from the oil supply groove 137 toward the bearing chamber 132 is a labyrinth groove as shown in FIG. 8 (B). The amount of lubricating oil flowing into the bearing 170 side can be reduced by the pressure loss caused by alternately passing the throttle portion formed between 139 and the expansion portion formed in the labyrinth groove 139. ..

しかし，この構成により，給油溝１３７に対する給油圧力を低下させることなく高圧設定の油冷式スクリュ圧縮機１００の軸受１７０に対する給油量を減少させようとした場合，油冷式スクリュ圧縮機１００の吐出側圧力の上昇分に対応した大幅な圧力損失を発生させるためにスペーサ１３６の外周面に多数のラビリンス溝１３９を形成することが必要で，このスペースを確保するために，スペーサ１３６の長さを長くする必要がある等，寸法変化等を伴った軸封部１３４の大幅な設計の見直しが必要となる。 However, with this configuration, when the amount of oil supplied to the bearing 170 of the oil-cooled screw compressor 100 set at high pressure is to be reduced without reducing the oil supply pressure to the oil-cooled groove 137, the oil-cooled screw compressor 100 is discharged. It is necessary to form a large number of labyrinth grooves 139 on the outer peripheral surface of the spacer 136 in order to generate a large pressure loss corresponding to the increase in the lateral pressure, and in order to secure this space, the length of the spacer 136 should be increased. It is necessary to drastically review the design of the shaft seal portion 134 due to dimensional changes such as the need to lengthen it.

そのため，スペーサ１３６の長さの変更等，軸封部１３４の大幅な設計変更を伴うことなく，例えば軸封用のスペーサ１３６の交換だけで，より効率的に軸受１７０に対する給油量を減らすことができる軸封構造が要望される。 Therefore, it is possible to more efficiently reduce the amount of oil supplied to the bearing 170 by simply replacing the spacer 136 for shaft sealing, for example, without major design changes of the shaft sealing portion 134 such as changing the length of the spacer 136. A possible shaft sealing structure is required.

ここで，軸受室１３２側に対する潤滑油の流入量を減少させるために，給油溝１３７内に潤滑油を供給する給油流路１９３を絞ることも考えられる。 Here, in order to reduce the inflow of the lubricating oil to the bearing chamber 132 side, it is conceivable to narrow the lubrication flow path 193 for supplying the lubricating oil into the lubrication groove 137.

しかし，給油溝１３７に対する給油量が減少すると，給油溝１３７内の圧力がロータ室１１１より漏出しようとする圧縮気体の圧力に抗することができなくなり，その結果，ロータ室１１１からの圧縮気体の漏出を防止できなくなる。 However, when the amount of refueling to the refueling groove 137 decreases, the pressure in the refueling groove 137 cannot withstand the pressure of the compressed gas that is about to leak from the rotor chamber 111, and as a result, the compressed gas from the rotor chamber 111 cannot withstand the pressure. Leakage cannot be prevented.

そこで，図８に示すように給油溝１３７に対しロータ室１１１側のスペーサ１３６外周面にも，断面矩形状のラビリンス溝１３８’を設け，ロータ室１１１から漏出する圧縮気体にも圧力損出を生じさせることで，給油溝１３７に対し給油する潤滑油の圧力を低下させることも考えられる。 Therefore, as shown in FIG. 8, a labyrinth groove 138'with a rectangular cross section is provided on the outer peripheral surface of the spacer 136 on the rotor chamber 111 side with respect to the lubrication groove 137, and pressure loss is also caused to the compressed gas leaking from the rotor chamber 111. It is also conceivable to reduce the pressure of the lubricating oil to be refueled to the refueling groove 137 by causing it.

しかし，給油溝１３７に対しロータ室１１１側に位置するスペーサ１３６の外周面と軸孔１３１内周面間の隙間Δには，図８（Ｃ）に示すようにロータ室１１１側から圧縮気体が導入されるだけでなく，給油溝１３７側からの潤滑油が導入される。 However, as shown in FIG. 8C, compressed gas flows from the rotor chamber 111 side in the gap Δ between the outer peripheral surface of the spacer 136 located on the rotor chamber 111 side with respect to the lubrication groove 137 and the inner peripheral surface of the shaft hole 131. Not only is it introduced, but the lubricating oil from the lubrication groove 137 side is introduced.

そして，この隙間Δ内において両流体の圧力が釣り合うと，ロータ室１１１の圧縮気体が前述の隙間Δを通過できなくなり、軸受室１３２への漏出防止が図れるが，図８（Ｃ）に示したように，断面矩形状，従って左右対称形状のラビリンス溝１３８’を設けた場合，このラビリンス溝１３８’は，ロータ室１１１から給油溝１３７側に向かう圧縮気体に圧力損失を生じさせるだけでなく，給油溝１３７からロータ室１１１側へ向かう潤滑油にも圧力損失を生じさせることになるため，断面矩形状のラビリンス溝１３８’を設けたとしても給油溝１３７内に潤滑油を供給する給油流路を絞って給油溝１３７に対する潤滑油の給油量を低下させてしまうと，ロータ室１１１からの圧縮気体の漏出を防止することができなくなる。 When the pressures of both fluids are balanced in this gap Δ, the compressed gas in the rotor chamber 111 cannot pass through the above-mentioned gap Δ, and leakage to the bearing chamber 132 can be prevented, which is shown in FIG. 8 (C). As described above, when the labyrinth groove 138'having a rectangular cross section and therefore a symmetrical shape is provided, this labyrinth groove 138'not only causes a pressure loss in the compressed gas from the rotor chamber 111 toward the oil supply groove 137 side, but also causes a pressure loss. Since pressure loss will also occur in the lubricating oil from the lubrication groove 137 toward the rotor chamber 111 side, even if the labyrinth groove 138'with a rectangular cross section is provided, the lubrication flow path for supplying the lubricating oil into the lubrication groove 137 If the amount of lubricating oil supplied to the oil supply groove 137 is reduced by squeezing the pressure, it becomes impossible to prevent the leakage of the compressed gas from the rotor chamber 111.

そこで，本発明の発明者は，給油溝１３７に対しロータ室１１１側に位置するスペーサ１３６の外周面に形成するラビリンス溝１３８’の断面形状を工夫することにより，給油溝１３７側からロータ室１１１側へ向かう潤滑油に対するよりも，ロータ室１１１側から給油溝１３７側に向かう圧縮気体に対してより大きな圧力損出を生じさせることができれば給油溝１３７に対する給油圧力を低下させた場合であってもロータ室１１１からの圧縮気体の漏出を防止できるのではないかとの考えの下，鋭意研究を重ね，本発明の完成に至った。 Therefore, the inventor of the present invention devised the cross-sectional shape of the labyrinth groove 138'formed on the outer peripheral surface of the spacer 136 located on the rotor chamber 111 side with respect to the lubrication groove 137, thereby allowing the rotor chamber 111 from the lubrication groove 137 side. If it is possible to generate a larger pressure loss for the compressed gas from the rotor chamber 111 side toward the lubrication groove 137 side than for the lubricating oil toward the side, it is the case where the lubrication pressure with respect to the lubrication groove 137 is lowered. Based on the idea that it may be possible to prevent the leakage of compressed gas from the rotor chamber 111, the present invention has been completed through repeated diligent studies.

このように，本発明は，ロータ室からの圧縮気体の漏出を防止するという軸封部の機能を維持しつつ，軸封部に対する給油量を減少させてもロータ室内の圧縮気体が軸受室側へ漏出することを防ぐことが可能であり，従って，軸封部に隣接して設けられた軸受に対する給油量の制御幅を広げることができる油冷式スクリュ圧縮機の軸封構造を提供することを目的とする。 As described above, the present invention maintains the function of the shaft sealing portion of preventing the leakage of the compressed gas from the rotor chamber, and even if the amount of oil supplied to the shaft sealing portion is reduced, the compressed gas in the rotor chamber is on the bearing chamber side. To provide a shaft seal structure for an oil-cooled screw compressor that can prevent leakage to the shaft and thus can expand the control range of the amount of oil supplied to the bearing provided adjacent to the shaft seal portion. With the goal.

以下に，課題を解決するための手段を，発明を実施するための形態で使用する符号と共に記載する。この符号は，特許請求の範囲の記載と発明を実施するための形態の記載との対応を明らかにするために記載したものであり，言うまでもなく，本発明の技術的範囲の解釈に制限的に用いられるものではない。 The means for solving the problem are described below together with the reference numerals used in the embodiment for carrying out the invention. This reference numeral is given to clarify the correspondence between the description of the scope of claims and the description of the form for carrying out the invention, and it goes without saying that the reference numerals are limited to the interpretation of the technical scope of the present invention. Not used.

上記目的を達成するために，本発明の油冷式スクリュ圧縮機１の軸封構造は，
ケーシング２内に形成されたロータ室１１内にオス，メス一対のスクリュロータ４０，５０を噛み合い状態で回転可能に収容し，前記ケーシング２に前記スクリュロータ４０，５０の吐出側ロータ軸４２，５２を挿入する軸孔３１と，該軸孔３１と連通し，前記吐出側ロータ軸４２，５２を支承する軸受７０，７０を収容する軸受室３２とを形成し，前記ロータ室１１と前記軸受室３２との間で前記吐出側ロータ軸４２，５２の外周面と前記軸孔３１の内周面間の隙間Δを封止する軸封部３４を備えた油冷式スクリュ圧縮機の軸封構造において，
前記軸受室３２，３２と前記ロータ室１１間の前記吐出側ロータ軸４２，５２の外周面及び／又は前記ロータ軸４２，５２の収容位置における前記軸孔３１の内周面（図示の例ではロータ軸４２，５２に外嵌されてロータ軸４２，５２の外周面を成すスペーサ３６の外周面）に，周方向に連続する無端環状の給油溝３７を形成すると共に，前記ケーシング２内に該給油溝３７に潤滑油を給油する給油流路９３を設け，
前記軸受室３２側から前記ロータ室１１側に向かって徐々に拡大する断面形状を有し，周方向に連続する無端環状のラビリンス溝３８を，前記給油溝３７に対し前記ロータ室１１側に位置する前記ロータ軸４２，５２の外周面及び／又は前記軸孔３１の内周面（図示の例ではロータ軸４２，５２の外周面を成すスペーサ３６の外周面）に，所定間隔で複数平行に設けたことを特徴とする（請求項１，図３～５参照）。 In order to achieve the above object, the shaft sealing structure of the oil-cooled screw compressor 1 of the present invention is
A pair of male and female screw rotors 40, 50 are rotatably housed in the rotor chamber 11 formed in the casing 2 in a meshed state, and the discharge side rotor shafts 42, 52 of the screw rotors 40, 50 are housed in the casing 2. A shaft hole 31 into which the rotor chamber 31 is inserted and a bearing chamber 32 that communicates with the shaft hole 31 and accommodates the bearings 70 and 70 that support the discharge side rotor shafts 42 and 52 are formed. A shaft sealing structure of an oil-cooled screw compressor provided with a shaft sealing portion 34 for sealing a gap Δ between the outer peripheral surface of the discharge side rotor shafts 42 and 52 and the inner peripheral surface of the shaft hole 31 between the 32 and 32. In,
The outer peripheral surface of the discharge side rotor shafts 42 and 52 between the bearing chambers 32 and 32 and the rotor chamber 11 and / or the inner peripheral surface of the shaft hole 31 at the accommodation position of the rotor shafts 42 and 52 (in the illustrated example). An endless annular lubrication groove 37 that is continuous in the circumferential direction is formed on the outer peripheral surface of the spacer 36 that is fitted onto the rotor shafts 42 and 52 and forms the outer peripheral surface of the rotor shafts 42 and 52, and the inside of the casing 2 is the same. A lubrication flow path 93 for supplying lubricating oil is provided in the lubrication groove 37.
An endless annular labyrinth groove 38 having a cross-sectional shape that gradually expands from the bearing chamber 32 side toward the rotor chamber 11 side and continuous in the circumferential direction is located on the rotor chamber 11 side with respect to the oil supply groove 37. A plurality of parallel surfaces at predetermined intervals on the outer peripheral surface of the rotor shafts 42 and 52 and / or the inner peripheral surface of the shaft hole 31 (in the illustrated example, the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the rotor shafts 42 and 52). It is characterized in that it is provided (see claim 1, FIGS. 3 to 5).

前記軸受室３２，３２と前記ロータ室１１間の前記吐出側ロータ軸４２，５２に外嵌されて，該位置における前記吐出側ロータ軸４２，５２の外径を拡大する円筒状のスペーサ３６を設け，該スペーサ３６の外周面を前記吐出側ロータ軸４２，５２の前記外周面とするものとしても良い（請求項２）。 A cylindrical spacer 36 that is fitted onto the discharge side rotor shafts 42 and 52 between the bearing chambers 32 and 32 and the rotor chamber 11 to expand the outer diameter of the discharge side rotor shafts 42 and 52 at the position is provided. The outer peripheral surface of the spacer 36 may be provided as the outer peripheral surface of the discharge side rotor shafts 42 and 52 (claim 2).

前記ラビリンス溝３８を，更に前記給油溝３７に対し前記軸受室３２側に位置する前記吐出側ロータ軸４２，５２の外周面及び／又は前記軸孔３１の内周面（図示の例では吐出側ロータ軸４２，５２の外周面を成すスペーサ３６の外周面）に対しても所定間隔で複数平行に設けるものとしても良い（請求項３，図３参照）。 The labyrinth groove 38 is further provided with an outer peripheral surface of the discharge side rotor shafts 42 and 52 located on the bearing chamber 32 side with respect to the oil supply groove 37 and / or an inner peripheral surface of the shaft hole 31 (discharge side in the illustrated example). A plurality of spacers 36 (the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the rotor shafts 42 and 52) may be provided in parallel at predetermined intervals (see claims 3 and 3).

又は，上記構成に代えて，断面矩形状を成し，周方向に連続する無端環状の矩形ラビリンス溝３９を，前記給油溝３７に対し前記軸受室３２側に位置する前記吐出側ロータ軸４２，５２の外周面及び／又は前記軸孔３１の内周面（図示の例では吐出側ロータ軸４２，５２の外周面を成すスペーサ３６の外周面）に所定間隔で複数平行に設けるものとしても良い（請求項４，図４参照）。 Alternatively, instead of the above configuration, the discharge side rotor shaft 42, which has a rectangular cross section and is located on the bearing chamber 32 side with respect to the oil supply groove 37, has a rectangular labyrinth groove 39 having an endless annular shape continuous in the circumferential direction. A plurality of parallel surfaces may be provided at predetermined intervals on the outer peripheral surface of the 52 and / or the inner peripheral surface of the shaft hole 31 (in the illustrated example, the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the discharge side rotor shafts 42 and 52). (See claims 4 and 4).

更に，前記給油溝３７に対し前記軸受室３２側の前記吐出側ロータ軸４２，５２の外周面（図示の例では吐出側ロータ軸４２，５２の外周面を成すスペーサ３６の外周面）と前記軸孔３１の内周面は，いずれも平滑面としてラビリンス溝を設けない構成としても良い（請求項５，図５参照）。 Further, the outer peripheral surface of the discharge side rotor shafts 42 and 52 on the bearing chamber 32 side (in the illustrated example, the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the discharge side rotor shafts 42 and 52) with respect to the oil supply groove 37 and the said. The inner peripheral surface of the shaft hole 31 may be configured such that no labyrinth groove is provided as a smooth surface (see claims 5 and 5).

以上で説明した本発明の構成により，本発明の油冷式スクリュ圧縮機１の軸封部３４では，以下の顕著な効果を得ることができた。 With the configuration of the present invention described above, the following remarkable effects can be obtained in the shaft sealing portion 34 of the oil-cooled screw compressor 1 of the present invention.

軸受室３２側からロータ室１１側に向かって徐々に拡大する断面形状を有し，周方向に連続する無端環状のラビリンス溝３８を，前記給油溝３７に対し前記ロータ室１１側に位置する吐出側ロータ軸４２，５２の外周面及び／又は前記軸孔３１の内周面（図示の例では吐出側ロータ軸４２，５２の外周面を成すスペーサ３６の外周面）に，所定間隔で複数平行に設けた構成（図３～図５参照）を採用したことで，給油溝３７に対する給油量を絞って給油溝３７内の潤滑油の圧力を，ロータ室１１より漏出する圧縮気体の圧力よりも低く設定した場合であっても，ロータ室１１からの圧縮気体の漏出を防止することができた。 A discharge having an endless annular labyrinth groove 38 having a cross-sectional shape that gradually expands from the bearing chamber 32 side toward the rotor chamber 11 side and being located on the rotor chamber 11 side with respect to the oil supply groove 37. A plurality of parallel surfaces at predetermined intervals on the outer peripheral surfaces of the side rotor shafts 42 and 52 and / or the inner peripheral surface of the shaft hole 31 (in the illustrated example, the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the discharge side rotor shafts 42 and 52). By adopting the configuration provided in (see FIGS. 3 to 5), the pressure of the lubricating oil in the refueling groove 37 is reduced to the pressure of the compressed gas leaking from the rotor chamber 11 by reducing the amount of refueling to the refueling groove 37. Even when the setting was low, it was possible to prevent the leakage of the compressed gas from the rotor chamber 11.

このように，給油溝３７に対する給油量の減少が可能となったことで，軸封部３４に隣接して設けられた軸受７０に対する給油量を減少させることが可能で，高圧設定の油冷式スクリュ圧縮機１においても軸受７０に対し過剰に潤滑油が給油されることを防止することができた。 In this way, since it is possible to reduce the amount of oil supplied to the oil supply groove 37, it is possible to reduce the amount of oil supplied to the bearing 70 provided adjacent to the shaft sealing portion 34, and it is an oil-cooled type with a high pressure setting. Also in the screw compressor 1, it was possible to prevent the bearing 70 from being excessively lubricated with lubricating oil.

その結果，軸受７０が過剰に給油された潤滑油を攪拌することにより生じる動力ロスの発生や，軸受７０に過剰に供給された潤滑油を圧縮作用空間内に回収することにより，スクリュロータ４０，５０が攪拌する潤滑油量が増加することにより生じる動力ロスの発生を防止することができた。 As a result, the screw rotor 40, by generating power loss caused by stirring the lubricating oil excessively supplied to the bearing 70 and recovering the lubricating oil excessively supplied to the bearing 70 into the compression action space, It was possible to prevent the occurrence of power loss caused by an increase in the amount of lubricating oil stirred by 50.

また，給油溝３７に対しロータ室１１側に前述したラビリンス溝３８を形成するだけでなく，給油溝３７に対し軸受室３２側にも同様の構造のラビリンス溝３８を形成する構成（図３参照）を採用し，又は，断面矩形状の矩形ラビリンス溝３９を形成する構成（図４参照）を採用することで，給油溝３７に対し軸受室３２側に位置する吐出側ロータ軸４２，５２の外周面（図示の例では吐出側ロータ軸４２，５２の外周面を成すスペーサ３６の外周面）と軸孔３１の内周面間の隙間Δを介して軸受室３２側に漏出する潤滑油の漏出量を減少させることができ，前述した給油溝３７に対する給油量の減少との相乗効果によって更に軸受７０に対する給油量を減少させることも可能である。 Further, not only the labyrinth groove 38 described above is formed on the rotor chamber 11 side of the lubrication groove 37, but also the labyrinth groove 38 having the same structure is formed on the bearing chamber 32 side of the lubrication groove 37 (see FIG. 3). ), Or by adopting a configuration (see FIG. 4) that forms a rectangular labyrinth groove 39 having a rectangular cross section, the discharge side rotor shafts 42 and 52 located on the bearing chamber 32 side with respect to the lubrication groove 37. Lubricating oil leaking to the bearing chamber 32 side through the gap Δ between the outer peripheral surface (in the illustrated example, the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the discharge side rotor shafts 42 and 52) and the inner peripheral surface of the shaft hole 31. The amount of leakage can be reduced, and the amount of oil supplied to the bearing 70 can be further reduced by the synergistic effect with the above-mentioned decrease in the amount of oil supplied to the oil supply groove 37.

更に，前記給油溝３７に対し前記軸受室３２側の前記吐出側ロータ軸４２，５２の外周面（図示の例では吐出側ロータ軸４２，５２の外周面を成すスペーサ３６の外周面）と前記軸孔３１の内周面を，いずれも平滑面とする構成（図５参照）を採用することにより，前述した給油溝３７に対する給油量の減少のみで軸受７０に対する給油量を減少させる構成としても良く，給油溝３７に対し軸受室側の部分で採用する構成を図３～図５に示した構成中より適宜選択して組み合わせることにより，軸受７０に対する給油量を細かく調整することも可能である。 Further, with respect to the oil supply groove 37, the outer peripheral surface of the discharge side rotor shafts 42 and 52 on the bearing chamber 32 side (in the illustrated example, the outer peripheral surface of the spacer 36 forming the outer peripheral surface of the discharge side rotor shafts 42 and 52) and the said. By adopting a configuration in which the inner peripheral surface of the shaft hole 31 is a smooth surface (see FIG. 5), the amount of oil supplied to the bearing 70 can be reduced only by reducing the amount of oil supplied to the oil supply groove 37 described above. It is also possible to finely adjust the amount of lubrication to the bearing 70 by appropriately selecting and combining the configurations adopted in the portion on the bearing chamber side with respect to the lubrication groove 37 from the configurations shown in FIGS. 3 to 5. ..

本発明の軸封構造が適用される油冷式スクリュ圧縮機の縮尺断面平面図。The scale sectional plan view of the oil-cooled screw compressor to which the shaft seal structure of this invention is applied. 本発明の軸封構造が適用される油冷式スクリュ圧縮機の縮尺断面正面図。The scale sectional front view of the oil-cooled screw compressor to which the shaft seal structure of this invention is applied. 図２の矢示III部分（破線で囲った部分）の（Ａ）は拡大図，（Ｂ）は（Ａ）の矢示B部分の拡大説明図，（Ｃ）は（Ａ）の矢示C部分の拡大説明図。(A) of the arrow III part (the part surrounded by the broken line) in FIG. 2 is an enlarged view, (B) is an enlarged explanatory view of the arrow B part of (A), and (C) is the arrow C of (A). Enlarged explanatory view of the part. 図２の矢示III部分（破線で囲った部分）の変形例を示す（Ａ）は拡大図，（Ｂ）は（Ａ）の矢示B部分の拡大説明図。(A) is an enlarged view, and (B) is an enlarged explanatory view of the arrow B part of (A) showing a modified example of the arrow III part (the part surrounded by the broken line) in FIG. 図２の矢示III部分（破線で囲った部分）の別の変形例を示す拡大図。An enlarged view showing another modification of the arrow III part (the part surrounded by the broken line) in FIG. 油冷式スクリュ圧縮機を圧縮機本体とした圧縮機ユニットの説明図。An explanatory diagram of a compressor unit using an oil-cooled screw compressor as the main body of the compressor. 従来の油冷式スクリュ圧縮機の軸封部の説明図（特許文献１の図２に対応）。Explanatory drawing of the shaft seal part of the conventional oil-cooled screw compressor (corresponding to FIG. 2 of Patent Document 1). 軸封部に軸封用のスペーサを設け，このスペーサにラビリンス溝を設ける構造を採用した場合を想定した（Ａ）は説明図，（Ｂ）は（Ａ）の矢示B部分の拡大説明図，（Ｃ）は（Ａ）の矢示C部分の拡大説明図。(A) is an explanatory diagram, and (B) is an enlarged explanatory view of the arrow B portion of (A) assuming a case where a spacer for shaft sealing is provided in the shaft sealing portion and a labyrinth groove is provided in this spacer. , (C) is an enlarged explanatory view of the arrow C part of (A).

次に，本発明の実施形態につき添付図面を参照しながら説明する。 Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

〔油冷式スクリュ圧縮機の全体構成〕
図１及び図２中の符号１は，本発明の軸封構造が適用される油冷式スクリュ圧縮機であり，この油冷式スクリュ圧縮機１は，外殻を成すケーシング２を備えている。 [Overall configuration of oil-cooled screw compressor]
Reference numeral 1 in FIGS. 1 and 2 is an oil-cooled screw compressor to which the shaft sealing structure of the present invention is applied, and the oil-cooled screw compressor 1 includes a casing 2 forming an outer shell. ..

このケーシング２は，ロータケーシング１０と，このロータケーシング１０の吸入側端部に取り付けられあるいはこれと一体に形成される吸入側ケーシング２０と，ロータケーシング１０の吐出側端部に取り付けられる吐出側ケーシング３０を備えており，このうちのロータケーシング１０内に形成されたロータ室１１内にオス・メス一対のスクリュロータ４０，５０が噛み合い回転可能に収容されている。 The casing 2 includes a rotor casing 10, a suction-side casing 20 attached to or integrally formed with the suction-side end of the rotor casing 10, and a discharge-side casing attached to the discharge-side end of the rotor casing 10. 30 is provided, and a pair of male and female screw rotors 40 and 50 are rotatably housed in a rotor chamber 11 formed in the rotor casing 10.

このロータケーシング１０の吸入側端部に取り付けた吸入側ケーシング２０にはスクリュロータ４０，５０の吸入側ロータ軸４１，５１を収容する軸孔が形成され，この軸孔と連通して形成された軸受室２１，２２内に軸受６０，６０を収容し，この軸受６０，６０にオス，メスの各スクリュロータ４０，５０の吸入側ロータ軸４１，５１が支承されている。 A shaft hole for accommodating the suction-side rotor shafts 41 and 51 of the screw rotors 40 and 50 is formed in the suction-side casing 20 attached to the suction-side end of the rotor casing 10, and is formed in communication with the shaft hole. Bearings 60 and 60 are housed in bearing chambers 21 and 22, and suction side rotor shafts 41 and 51 of male and female screw rotors 40 and 50 are supported in the bearings 60 and 60.

また，この吸入側ケーシング２０には，ギヤ室２３が形成されており，このギヤ室２３内には，オス，メスいずれかのスクリュロータ４０，５０に対して，図示せざるモータやエンジン等の駆動源からの回転駆動力を増速して入力する増速装置８０が収容されている。 Further, a gear chamber 23 is formed in the suction side casing 20, and in the gear chamber 23, a motor, an engine, or the like (not shown) is provided for either a male or female screw rotor 40, 50. A speed increasing device 80 for increasing and inputting a rotational driving force from a driving source is housed.

この増速装置８０は，一例としていずれか一方のスクリュロータ４０又は５０の吸入側ロータ軸（本実施形態にあってはオスロータ４０の吸入側ロータ軸４１）に固着された従動歯車８１と，この従動歯車８１に対して回転駆動力を伝達する駆動歯車８２，及び前記駆動歯車８２に駆動源で発生した回転駆動力を入力する駆動軸８３を備え，前記駆動歯車８２に対して従動歯車８１を小径とすることにより，駆動軸８３を介して入力された回転駆動力が増速されてオスロータ４０の吸入側ロータ軸４１に伝達され，スクリュロータ４０，５０を増速回転させることができるように構成されている。 As an example, the speed increasing device 80 includes a driven gear 81 fixed to a suction side rotor shaft of either screw rotor 40 or 50 (in this embodiment, a suction side rotor shaft 41 of the male rotor 40). A drive gear 82 that transmits rotational drive force to the driven gear 81 and a drive shaft 83 that inputs rotational drive force generated by a drive source to the drive gear 82 are provided, and the driven gear 81 is provided to the drive gear 82. By making the diameter small, the rotational driving force input via the drive shaft 83 is accelerated and transmitted to the suction side rotor shaft 41 of the male rotor 40 so that the screw rotors 40 and 50 can be rotated at an accelerated speed. It is configured.

なお，本発明の油冷式スクリュ圧縮機１において，上記増速装置８０及び上記ギヤ室２３は必須の構成ではなく，油冷式スクリュ圧縮機１の外部に増速装置を設けたり，駆動源からの回転駆動力を増速することなくそのままの回転速度で入力したりする場合など，増速装置８０及びギヤ室２３を設けない場合には，オス・メスいずれか一方の吸入側ロータ軸，例えばオスロータ４０の吸入側ロータ軸４１を，ケーシングを貫通させて機外に突設し，これを駆動軸としてエンジンやモータからの回転駆動力を入力するように構成しても良い。 In the oil-cooled screw compressor 1 of the present invention, the speed-increasing device 80 and the gear chamber 23 are not indispensable configurations, and a speed-increasing device may be provided outside the oil-cooled screw compressor 1 or a drive source. When the speed-increasing device 80 and the gear chamber 23 are not provided, such as when the rotational driving force is input at the same rotational speed without increasing the speed, either the male or female suction side rotor shaft, For example, the suction side rotor shaft 41 of the male rotor 40 may be configured to penetrate the casing and project outside the machine, and use this as the drive shaft to input the rotational driving force from the engine or motor.

ロータケーシング１０の吐出側端部は，オスロータ４０及びメスロータ５０の吐出側ロータ軸４２，５２を収容する軸孔３１，３１を備えた吐出側ケーシング３０で覆われており，スクリュロータ４０，５０の吐出側ロータ軸４２，５２を，前記吐出側ケーシング３０の軸孔３１，３１と連通して形成された軸受室３２，３２内に収容された軸受７０で支承している。 The discharge side end of the rotor casing 10 is covered with a discharge side casing 30 having shaft holes 31 and 31 for accommodating the discharge side rotor shafts 42 and 52 of the male rotor 40 and the female rotor 50, and the screw rotors 40 and 50. The discharge side rotor shafts 42 and 52 are supported by bearings 70 housed in bearing chambers 32 and 32 formed in communication with the shaft holes 31 and 31 of the discharge side casing 30.

なお，前述の吸入側ケーシング２０には吸気口２４が形成されており（図２参照），この吸気口２４を介して導入された被圧縮気体が，オス・メス一対のスクリュロータ４０，５０とロータ室１１の内壁によって画成される圧縮作用空間内に導入されて潤滑油と共に圧縮され，吐出側ケーシング３０に設けられた吐出口３３（図２参照）を介して機外に吐出されるように構成されている。 An intake port 24 is formed in the above-mentioned suction side casing 20 (see FIG. 2), and the compressed gas introduced through the intake port 24 is a pair of male and female screw rotors 40 and 50. It is introduced into the compression action space defined by the inner wall of the rotor chamber 11, compressed together with the lubricating oil, and discharged to the outside of the machine through the discharge port 33 (see FIG. 2) provided in the discharge side casing 30. It is configured in.

この油冷式スクリュ圧縮機１のロータケーシング１０の底部には，図６を参照して説明したレシーバタンク２２０からの給油配管２２４が連通される給油口１２（図２参照）が設けられていると共に，この給油口１２に連通して，ケーシングの肉厚内には，油冷式スクリュ圧縮機１内の給油を必要とする各部に対して潤滑油を給油する給油流路９１，９２，９３が形成されている。 At the bottom of the rotor casing 10 of the oil-cooled screw compressor 1, a lubrication port 12 (see FIG. 2) through which the lubrication pipe 224 from the receiver tank 220 described with reference to FIG. 6 is communicated is provided. At the same time, the lubrication flow paths 91, 92, 93 that communicate with the lubrication port 12 and lubricate each part of the oil-cooled screw compressor 1 that requires lubrication within the thickness of the casing. Is formed.

図示の実施形態では，図２に示すように，給油口１２より３方向に分岐された給油流路９１，９２，９３を設け，そのうちの１つ９１を吸気閉込後の圧縮作用空間に連通して，圧縮作用空間に潤滑，冷却，及び密封のための潤滑油を給油することができるように構成している。 In the illustrated embodiment, as shown in FIG. 2, a lubrication flow path 91, 92, 93 branched in three directions from the lubrication port 12 is provided, and one of 91 is communicated with the compression action space after the intake air is closed. Therefore, the compression working space is configured to be able to be lubricated with lubricating oil for lubrication, cooling, and sealing.

また，残りの給油流路の一方９２は，ロータケーシング１０の肉厚内を吸入側に向かって延びて吸入側ケーシング２０内に至り，この吸入側ケーシング２０内において増速装置８０が収容されたギヤ室２３内に潤滑油を噴射する給油ノズル２５に連通されており，これによりギヤ室２３内に収容された増速装置８０や，ギヤ室２３に連通して設けられた軸受室２１，２２内に収容された軸受６０，６０等を潤滑することができるように構成されている。 Further, one of the remaining lubrication flow paths 92 extends from the thickness of the rotor casing 10 toward the suction side to reach the inside of the suction side casing 20, and the speed increasing device 80 is housed in the suction side casing 20. A lubrication nozzle 25 for injecting lubricating oil into the gear chamber 23 is communicated with the speed increasing device 80 housed in the gear chamber 23, and bearing chambers 21 and 22 provided in communication with the gear chamber 23. It is configured to be able to lubricate the bearings 60, 60, etc. housed inside.

このギヤ室２３は，図示せざる連通路によってロータ室１１と連通しており，ギヤ室２３内に所定の油面高さ以上に溜まった潤滑油は，この連通孔（図示せず）を介してロータ室１１内に導入されて被圧縮気体と共に圧縮されるように構成されている。 The gear chamber 23 communicates with the rotor chamber 11 by a communication passage (not shown), and the lubricating oil accumulated in the gear chamber 23 above a predetermined oil level height passes through the communication hole (not shown). It is configured to be introduced into the rotor chamber 11 and compressed together with the compressed gas.

更に，給油流路の残りの１つ９３は，図２に示すようにロータケーシング１０の肉厚内を吐出側に延びた後，吐出側ケーシング３０内に至り吐出側ロータ軸４２，５２の軸線と直交する方向に向きを変えて，吐出側の軸封部３４，３４と，この軸封部３４，３４に隣接して設けられた軸受７０，７０に対し潤滑油を供給することができるように構成されている。 Further, as shown in FIG. 2, the remaining one 93 of the refueling flow path extends to the discharge side within the wall thickness of the rotor casing 10 and then reaches the inside of the discharge side casing 30 to reach the axis of the discharge side rotor shafts 42 and 52. Lubricating oil can be supplied to the shaft sealing portions 34, 34 on the discharge side and the bearings 70, 70 provided adjacent to the shaft sealing portions 34, 34 by changing the direction in the direction orthogonal to the shaft sealing portion 34, 34. It is configured in.

この吐出側の軸封部３４，３４と軸受７０，７０を潤滑した潤滑油は，軸受７０，７０に対し機外側に設けられた潤滑油回収室３５に導入され，この潤滑油回収室３５に連通する潤滑油回収流路９４（図１参照）を介して圧縮作用空間に回収されるように構成されている。 The lubricating oil that lubricated the shaft sealing portions 34, 34 on the discharge side and the bearings 70, 70 was introduced into the lubricating oil recovery chamber 35 provided on the outside of the machine with respect to the bearings 70, 70, and was introduced into the lubricating oil recovery chamber 35. It is configured to be recovered in the compression action space via the communicating lubricating oil recovery flow path 94 (see FIG. 1).

〔軸封構造〕
図１及び図２を参照して説明した油冷式スクリュ圧縮機１の吐出側ケーシング３０には，吐出側ロータ軸４２，５２を収容するための軸孔３１，３１が設けられていると共に，この軸孔３１，３１と連通して設けた軸受室３２，３２に収容された軸受７０，７０によって，吐出側ロータ軸４２，５２が回転可能に支承されている。 [Shaft sealing structure]
The discharge side casing 30 of the oil-cooled screw compressor 1 described with reference to FIGS. 1 and 2 is provided with shaft holes 31 and 31 for accommodating the discharge side rotor shafts 42 and 52. The discharge side rotor shafts 42 and 52 are rotatably supported by the bearings 70 and 70 housed in the bearing chambers 32 and 32 provided in communication with the shaft holes 31 and 31.

そして，この軸受室３２，３２とロータ室１１間には，ロータ室１１からの圧縮気体の漏出を防止するための前述の軸封部３４，３４が設けられている。 The shaft sealing portions 34, 34 for preventing the leakage of the compressed gas from the rotor chamber 11 are provided between the bearing chambers 32, 32 and the rotor chamber 11.

図３に，オスロータ４０の吐出側ロータ軸４２に設けた軸封部３４の構成例を示す。 FIG. 3 shows a configuration example of the shaft sealing portion 34 provided on the discharge side rotor shaft 42 of the male rotor 40.

図３に示すように，軸封部３４において吐出側ロータ軸４２の外径が軸孔３１の内径に対し僅かに小さく形成されており，この部分の吐出側ロータ軸４２の外周面と軸孔３１の内周面間の隙間Δが狭められていると共に，後述するようにこの隙間Δに潤滑油を給油して封止することで，ロータ室１１から圧縮気体の漏出が防止されている。 As shown in FIG. 3, in the shaft sealing portion 34, the outer diameter of the discharge side rotor shaft 42 is formed to be slightly smaller than the inner diameter of the shaft hole 31, and the outer peripheral surface and the shaft hole of the discharge side rotor shaft 42 in this portion. The gap Δ between the inner peripheral surfaces of the 31 is narrowed, and as will be described later, lubricating oil is supplied to and sealed in this gap Δ to prevent leakage of compressed gas from the rotor chamber 11.

軸封部３４における吐出側ロータ軸４２の外径は，該位置の吐出側ロータ軸４２自体の外径を軸孔３１の内径に対し僅かに小さく形成するものとしても良いが，図３に示す実施形態では，この位置の吐出側ロータ軸４２に軸封用の円筒状のスペーサ３６を外嵌し，このスペーサ３６によって吐出側ロータ軸４２の外径を拡張してスペーサ３６の外周面と軸孔３１の内周面間を前述の隙間Δとしても良く，この場合，スペーサ３６の外周面が，吐出側ロータ軸４２の外周面となる。 The outer diameter of the discharge side rotor shaft 42 in the shaft sealing portion 34 may be formed so that the outer diameter of the discharge side rotor shaft 42 itself at the position is slightly smaller than the inner diameter of the shaft hole 31, but is shown in FIG. In the embodiment, a cylindrical spacer 36 for shaft sealing is externally fitted to the discharge side rotor shaft 42 at this position, and the outer diameter of the discharge side rotor shaft 42 is expanded by the spacer 36 to expand the outer diameter of the discharge side rotor shaft 42 to cover the outer peripheral surface and shaft of the spacer 36. The space between the inner peripheral surfaces of the holes 31 may be the above-mentioned gap Δ, and in this case, the outer peripheral surface of the spacer 36 becomes the outer peripheral surface of the discharge side rotor shaft 42.

このスペーサ３６は，軸孔３１の内周面と非接触の状態で吐出側ロータ軸４２と共に回転するよう，吐出側ロータ軸４２の外周に取り付けられており，このスペーサ３６の外周面と軸孔３１の内周面間に生じた隙間Δに潤滑油を給油してこの隙間Δを塞ぐことでロータ室１１からの圧縮気体の漏出を防止すると共に，この隙間Δを介して軸受室３２側に潤滑油を漏出させることで，軸受７０に対する給油を行うことができるように構成されている。 The spacer 36 is attached to the outer peripheral surface of the discharge side rotor shaft 42 so as to rotate together with the discharge side rotor shaft 42 in a non-contact state with the inner peripheral surface of the shaft hole 31, and the outer peripheral surface and the shaft hole of the spacer 36. Lubricating oil is supplied to the gap Δ generated between the inner peripheral surfaces of 31 to close the gap Δ to prevent leakage of compressed gas from the rotor chamber 11 and to the bearing chamber 32 side through this gap Δ. It is configured so that the bearing 70 can be refueled by leaking the lubricating oil.

このスペーサ３６の軸線方向における中間位置の外周面には，周方向に連続する無端環状の給油溝３７が形成されていると共に，吐出側ケーシング３０内において吐出側ロータ軸４２の軸線方向に対し直交方向に形成された前述の給油流路９３を，この給油溝３７と連通させて，給油溝３７に対しレシーバタンクより圧送された潤滑油を給油することができるように構成されている。 An endless annular lubrication groove 37 continuous in the circumferential direction is formed on the outer peripheral surface of the spacer 36 at an intermediate position in the axial direction, and is orthogonal to the axial direction of the discharge side rotor shaft 42 in the discharge side casing 30. The above-mentioned lubrication flow path 93 formed in the direction is communicated with the lubrication groove 37 so that the lubricating oil pumped from the receiver tank can be supplied to the lubrication groove 37.

前述のスペーサ３６の外周面のうち，少なくとも給油溝３７よりもロータ室１１側に位置する部分には，軸受室３２側からロータ室１１側に向かって徐々に拡大する断面形状を有し，周方向に連続する無端環状に形成されたラビリンス溝３８が，所定間隔で複数（図示の例では４つ）平行に設けられており，該部分のスペーサ３６の表面が，全体として断面鋸歯状に形成されている。 Of the outer peripheral surface of the spacer 36 described above, at least a portion located on the rotor chamber 11 side of the oil supply groove 37 has a cross-sectional shape that gradually expands from the bearing chamber 32 side toward the rotor chamber 11 side, and has a circumferential shape. A plurality of labyrinth grooves 38 formed in an endless annular shape continuous in the direction (four in the illustrated example) are provided in parallel at predetermined intervals, and the surface of the spacer 36 in the portion is formed in a cross-sectional sawtooth shape as a whole. Has been done.

図３に示した実施形態では，このような断面形状を有するラビリンス溝３８を給油溝３７に対し軸受室３２側に位置するスペーサ３６の外周面にも同様に所定間隔で複数（図示の例では５つ）平行に設けている。 In the embodiment shown in FIG. 3, a plurality of labyrinth grooves 38 having such a cross-sectional shape are similarly provided at predetermined intervals on the outer peripheral surface of the spacer 36 located on the bearing chamber 32 side with respect to the oil supply groove 37 (in the illustrated example). 5) It is provided in parallel.

このように，軸受室３２側からロータ室１１側に向かって徐々に拡大する断面形状を有するラビリンス溝３８を形成することで，給油溝３７に対する給油量を減少させて給油溝３７内の潤滑油の圧力を，ロータ室１１より漏出しようとする圧縮気体の圧力よりも低い圧力とした場合であっても，ロータ室１１からの圧縮気体の漏出を防止することができた。 By forming the labyrinth groove 38 having a cross-sectional shape that gradually expands from the bearing chamber 32 side to the rotor chamber 11 side in this way, the amount of lubrication to the lubrication groove 37 is reduced and the lubricating oil in the lubrication groove 37 is reduced. Even when the pressure was set to be lower than the pressure of the compressed gas to leak from the rotor chamber 11, it was possible to prevent the compressed gas from leaking from the rotor chamber 11.

ここで，給油溝３７に供給されて，給油溝３７から軸受室３２側に向かって流れる潤滑油は，図３（Ｂ）に拡大図で示すように，ラビリンス溝３８間に形成された絞り部を通過した後，ラビリンス溝３８内に形成された拡大部に至り流路が急激に拡大することで，図８（Ｂ）を参照して説明した矩形の断面を有するラビリンス溝を設けた場合と同様，絞られた状態から急激に拡大する流路を繰り返し通過することで圧力損失が生じ，これを繰り返すことで軸受室３２に向かって隙間Δを通過する潤滑油量を減らすことができる。 Here, the lubricating oil supplied to the lubrication groove 37 and flowing from the lubrication groove 37 toward the bearing chamber 32 side is a throttle portion formed between the labyrinth grooves 38 as shown in an enlarged view in FIG. 3B. When the labyrinth groove having a rectangular cross section described with reference to FIG. 8B is provided by reaching the enlarged portion formed in the labyrinth groove 38 and rapidly expanding the flow path after passing through the above. Similarly, pressure loss occurs by repeatedly passing through a flow path that rapidly expands from the throttled state, and by repeating this, the amount of lubricating oil that passes through the gap Δ toward the bearing chamber 32 can be reduced.

同様に，ロータ室１１側から給油溝３７側に向かって，スペーサ３６の外周面と軸孔３１の内周面間の隙間Δを通過しようとする圧縮性流体である圧縮気体も，図３（Ｃ）に示すように絞り部から拡大部に至り急激に拡大する流路を通過して給油溝３７側に移動することで，断面が矩形のラビリンス溝を設けた場合と同様，圧縮された状態から急激に膨張するとともにこれを繰り返すことで大きな圧力損失を受けることになる。 Similarly, the compressed gas, which is a compressible fluid that tries to pass through the gap Δ between the outer peripheral surface of the spacer 36 and the inner peripheral surface of the shaft hole 31 from the rotor chamber 11 side toward the oil supply groove 37 side, is also shown in FIG. As shown in C), by moving from the narrowed portion to the enlarged portion through the rapidly expanding flow path to the oil supply groove 37 side, the compressed state is obtained as in the case where the labyrinth groove having a rectangular cross section is provided. It expands rapidly from the beginning and repeats this, resulting in a large pressure loss.

しかし，給油溝３７からロータ室１１側に向かう非圧縮性流体である潤滑油は，絞り部から拡大部に至り徐々に拡大する流路を通過することで，流速が低下する一方，圧力が上昇するものとなっており（ベルヌーイの定理），これらが繰り返し起きることで，「圧縮気体の圧力 ≦ 潤滑油の圧力」という状態になり，ロータ室からの圧縮気体の漏出防止が可能となる。 However, the lubricating oil, which is an incompressible fluid flowing from the oil supply groove 37 toward the rotor chamber 11, passes through a flow path that gradually expands from the throttle portion to the expansion portion, so that the flow velocity decreases while the pressure increases. (Bernoulli's theorem), and when these occur repeatedly, the state of "pressure of compressed gas ≤ pressure of lubricating oil" is established, and it is possible to prevent leakage of compressed gas from the rotor chamber.

その結果，絞り部から拡大部に至り流路面積が急激に拡大する側をロータ室１１側，絞り部から拡大部に至り流路面積が徐々に拡大する側を軸受室３２側として吐出側ロータ軸４２にスペーサ３６を取り付けることで，給油溝３７に対する給油圧力を，ロータ室１１より漏出しようとする圧縮気体の圧力よりも低い圧力とした場合であっても，ロータ室１１より漏出する圧縮気体の圧力に対抗させることが可能となり，ロータ室１１からの圧縮気体の漏出を防止できる。 As a result, the side from the throttle portion to the enlarged portion where the flow path area rapidly expands is the rotor chamber 11 side, and the side from the throttle portion to the enlarged portion where the flow path area gradually expands is the bearing chamber 32 side. By attaching the spacer 36 to the shaft 42, even if the refueling pressure for the refueling groove 37 is lower than the pressure of the compressed gas that is about to leak from the rotor chamber 11, the compressed gas that leaks from the rotor chamber 11 It is possible to counter the pressure of the above, and it is possible to prevent the leakage of the compressed gas from the rotor chamber 11.

このように給油溝３７に対する給油量を減少させることができたことで，本発明の軸封部構造を備えた油冷式スクリュ圧縮機１では，給油溝３７から軸受室３２に向かってスペーサ３６の外周面と軸孔３１の内周面間の隙間Δを介して軸受室３２側に流入する潤滑油量を減少させることができた。 Since the amount of oil supplied to the oil supply groove 37 can be reduced in this way, in the oil-cooled screw compressor 1 provided with the shaft sealing portion structure of the present invention, the spacer 36 is directed from the oil supply groove 37 toward the bearing chamber 32. It was possible to reduce the amount of lubricating oil flowing into the bearing chamber 32 side through the gap Δ between the outer peripheral surface and the inner peripheral surface of the shaft hole 31.

しかも，図３に示した実施形態では，給油溝３７と軸受室３２間のスペーサ３６の外周面に，前述したように，ロータ室１１と給油溝３７間に設けたと同様の断面形状を有するラビリンス溝３８を設けたことで，この部分を通過して軸受室３２側に漏出する潤滑油量を減少させることができる。 Moreover, in the embodiment shown in FIG. 3, a labyrinth having the same cross-sectional shape as that provided between the rotor chamber 11 and the oil supply groove 37 on the outer peripheral surface of the spacer 36 between the oil supply groove 37 and the bearing chamber 32, as described above. By providing the groove 38, the amount of lubricating oil that passes through this portion and leaks to the bearing chamber 32 side can be reduced.

このように軸受７０に対する給油量を減少させることができたことで，高圧設定の油冷式スクリュ圧縮機１であっても軸受７０が多量の潤滑油を攪拌することにより生じる動力ロスの発生を防止することができた。 Since the amount of oil supplied to the bearing 70 can be reduced in this way, even in the oil-cooled screw compressor 1 set at a high pressure, the bearing 70 stirs a large amount of lubricating oil to cause power loss. I was able to prevent it.

また，軸受７０に対する給油量を減少させることができたことで，軸受７０を潤滑した後，潤滑油回収室３５及び潤滑油回収流路９４（図２参照）を介して圧縮作用空間に回収される潤滑油量が減少することで，スクリュロータ４０，５０が余分な潤滑油を攪拌することによって生じる動力ロスの発生についても防止することができた。 Further, since the amount of oil supplied to the bearing 70 could be reduced, after lubricating the bearing 70, it was recovered in the compression action space via the lubricating oil recovery chamber 35 and the lubricating oil recovery flow path 94 (see FIG. 2). By reducing the amount of lubricating oil, it was possible to prevent the occurrence of power loss caused by the screw rotors 40 and 50 stirring the excess lubricating oil.

以上，図３を参照して説明した軸封部３４では，給油溝３７に対し軸受室３２側に位置するスペーサ３６の外周面に設けるラビリンス溝３８と，給油溝３７に対しロータ室１１側のスペーサ３６の外周面に設けたラビリンス溝３８の断面形状を，いずれも軸受室３２側からロータ室１１側に向かって徐々に拡大する形状とした。 In the shaft sealing portion 34 described with reference to FIG. 3, the labyrinth groove 38 provided on the outer peripheral surface of the spacer 36 located on the bearing chamber 32 side with respect to the oil supply groove 37 and the rotor chamber 11 side with respect to the oil supply groove 37. The cross-sectional shape of the labyrinth groove 38 provided on the outer peripheral surface of the spacer 36 is a shape that gradually expands from the bearing chamber 32 side to the rotor chamber 11 side.

この構成に代えて，給油溝３７に対し軸受室３２側に位置するスペーサ３６の外周面に設けるラビリンス溝は，図４に示すように，断面矩形状の矩形ラビリンス溝３９としても良い。 Instead of this configuration, the labyrinth groove provided on the outer peripheral surface of the spacer 36 located on the bearing chamber 32 side with respect to the oil supply groove 37 may be a rectangular labyrinth groove 39 having a rectangular cross section as shown in FIG.

給油溝３７に対し軸受室３２側のスペーサ３６外周面と軸孔３１の内周面間の隙間Δには，給油溝３７から軸受室３２側に向かう潤滑油の流れのみが生じ，逆向きの流体の流れについて考慮する必要がなく，この部分に形成するラビリンス溝の形状としては，軸受室３２側に漏出する潤滑油量を減少させることができるものであれば，如何なる断面形状のラビリンス溝を採用しても良い。 In the gap Δ between the outer peripheral surface of the spacer 36 on the bearing chamber 32 side and the inner peripheral surface of the shaft hole 31 with respect to the lubrication groove 37, only the flow of lubricating oil from the lubrication groove 37 toward the bearing chamber 32 side occurs, and the direction is opposite. It is not necessary to consider the flow of fluid, and the shape of the labyrinth groove formed in this portion is any cross-sectional shape as long as the amount of lubricating oil leaking to the bearing chamber 32 side can be reduced. You may adopt it.

しかも，形成するラビリンス溝の溝幅，深さを同じくする場合，軸受室３２側からロータ室１１側に向かって徐々に拡大する断面形状のラビリンス溝３８に比較して，断面形状を矩形としたラビリンス溝３９の方が拡大部の断面積が大きくなり，隙間Δを通過する潤滑油の流れをより急拡大，急縮小させるものとなることでより大きな圧力損失を生じさせることができ，この部分を通過する潤滑剤の量をより一層減少させることが可能となる。 Moreover, when the groove width and depth of the labyrinth groove to be formed are the same, the cross-sectional shape is rectangular as compared with the labyrinth groove 38 having a cross-sectional shape that gradually expands from the bearing chamber 32 side to the rotor chamber 11 side. The labyrinth groove 39 has a larger cross-sectional area of the enlarged portion, and the flow of the lubricating oil passing through the gap Δ is expanded and contracted more rapidly, so that a larger pressure loss can be generated. It is possible to further reduce the amount of lubricant passing through.

従って，軸受７０に対する給油量をより減少させることが必要となる場合，図４に示すように，給油溝３７に対し軸受室３２側に設けるラビリンス溝を断面が矩形である矩形ラビリンス溝３９とすることで，このような要求に対応することが可能となる。 Therefore, when it is necessary to further reduce the amount of oil supplied to the bearing 70, as shown in FIG. 4, the labyrinth groove provided on the bearing chamber 32 side with respect to the oil supply groove 37 is a rectangular labyrinth groove 39 having a rectangular cross section. This makes it possible to meet such demands.

更に，図３及び図４を参照して説明した軸封部３４では，給油溝３７に対しロータ室１１側のスペーサ３６の外周面だけでなく，給油溝３７に対し軸受室３２側のスペーサ３６外周面に対してもラビリンス溝３８，３９を設ける構成を説明したが，この構成に代えて，給油溝３７に対し軸受室３２側のスペーサ３６の外周面には，図５に示すようにラビリンス溝を設けない，平坦な表面に形成するものとしても良い。 Further, in the shaft sealing portion 34 described with reference to FIGS. 3 and 4, not only the outer peripheral surface of the spacer 36 on the rotor chamber 11 side with respect to the oil supply groove 37 but also the spacer 36 on the bearing chamber 32 side with respect to the oil supply groove 37. Although the configuration in which the labyrinth grooves 38 and 39 are provided on the outer peripheral surface has also been described, instead of this configuration, the labyrinth on the outer peripheral surface of the spacer 36 on the bearing chamber 32 side with respect to the oil supply groove 37 is as shown in FIG. It may be formed on a flat surface without providing a groove.

このように構成することで，図３及び図４を参照して説明した実施形態に比較して，軸受７０に対する給油量が増加することとなるが，スクリュロータ４０，５０を比較的早い回転速度で回転させる油冷式スクリュ圧縮機１等，軸受７０に対する給油量を比較的多くする必要がある油冷式スクリュ圧縮機１も存在することから，給油溝３７に対し軸受室３２側のスペーサ３６外周面の構造は，油冷式スクリュ圧縮機１の設定等に対応して，図３～５に示した構成より適宜選択して適用することができる。 With this configuration, the amount of oil supplied to the bearing 70 increases as compared with the embodiment described with reference to FIGS. 3 and 4, but the screw rotors 40 and 50 have relatively high rotation speeds. Since there is also an oil-cooled screw compressor 1 that requires a relatively large amount of oil to be supplied to the bearing 70, such as an oil-cooled screw compressor 1 that is rotated by the oil-cooled screw compressor 1, the spacer 36 on the bearing chamber 32 side with respect to the oil supply groove 37. The structure of the outer peripheral surface can be appropriately selected and applied from the configurations shown in FIGS. 3 to 5 in accordance with the setting of the oil-cooled screw compressor 1 and the like.

なお，図３～図５を参照した実施形態では，いずれもスペーサ３６を単一の円筒状部材によって構成する例を示したが，一例として図５中に変更例として示したように，スペーサ３６を軸線方向に二分割して二部材の組み合わせにより形成するものとしても良い。 In the embodiments with reference to FIGS. 3 to 5, an example in which the spacer 36 is composed of a single cylindrical member is shown, but as an example, as shown as a modification in FIG. 5, the spacer 36 is shown. May be divided into two in the axial direction and formed by a combination of the two members.

この構成では，スペーサ３６のうち，ロータ室１１側に配置される部分３６ａの外周面に軸受室３２側からロータ室１１側に向かって徐々に拡大する断面形状のラビリンス溝３８を形成しておく。 In this configuration, a labyrinth groove 38 having a cross-sectional shape that gradually expands from the bearing chamber 32 side toward the rotor chamber 11 side is formed on the outer peripheral surface of the portion 36a arranged on the rotor chamber 11 side of the spacer 36. ..

一方，軸受室側に配置される部分３６ｂについては，図３に示したラビリンス溝３８，又は図４に示した矩形ラビリンス溝３９が設けられたもの，又は，図５に示すようにラビリンス溝を設けていないものを予め準備しておき，油冷式スクリュ圧縮機１の設定等に応じて，これらの中から選択した軸受室側に配置される部分３６ｂを組み合わせることによりスペーサ３６を形成するものとしても良い。 On the other hand, regarding the portion 36b arranged on the bearing chamber side, the labyrinth groove 38 shown in FIG. 3 or the rectangular labyrinth groove 39 shown in FIG. 4 is provided, or the labyrinth groove is provided as shown in FIG. A spacer 36 is formed by preparing in advance what is not provided and combining the portions 36b arranged on the bearing chamber side selected from these according to the setting of the oil-cooled screw compressor 1. It may be.

更に，図３～図５を参照して説明した実施形態では，いずれも，前述した給油溝３７やラビリンス溝３８，矩形ラビリンス溝３９を，スペーサ３６の外周面に形成する構成について説明したが，これらはいずれも，スペーサ３６の外周面に形成する構成と共に，又は，スペーサ３６の外周面に形成する構成に代えて，スペーサ３６に対応する位置の前記軸孔３１の内周面に形成するものとしても良く，この構成の採用によっても同様の効果を得ることができる。 Further, in the embodiments described with reference to FIGS. 3 to 5, the configuration in which the above-mentioned refueling groove 37, labyrinth groove 38, and rectangular labyrinth groove 39 are formed on the outer peripheral surface of the spacer 36 has been described. All of these are formed on the inner peripheral surface of the shaft hole 31 at the position corresponding to the spacer 36 together with the configuration formed on the outer peripheral surface of the spacer 36 or instead of the configuration formed on the outer peripheral surface of the spacer 36. However, the same effect can be obtained by adopting this configuration.

１ 油冷式スクリュ圧縮機
２ ケーシング
１０ ロータケーシング
１１ ロータ室
１２ 給油口
２０ 吸入側ケーシング
２１，２２ 軸受室
２３ ギヤ室
２４ 吸気口
２５ 給油ノズル
３０ 吐出側ケーシング
３１ 軸孔
３２ 軸受室
３３ 吐出口
３４ 軸封部
３５ 潤滑油回収室
３６ スペーサ
３６ａ （スペーサの）ロータ室側に配置される部分
３６ｂ （スペーサの）軸受室側に配置される部分
３７ 給油溝
３８ ラビリンス溝
３９ 矩形ラビリンス溝
４０ オスのスクリュロータ
４１ 吸入側ロータ軸
４２ 吐出側ロータ軸
５０ メスのスクリュロータ
５１ 吸入側ロータ軸
５２ 吐出側ロータ軸
６０，７０ 軸受
８０ 増速装置
８１ 従動歯車
８２ 駆動歯車
８３ 駆動軸
９１，９２，９３ 給油流路
９４ 潤滑油回収流路
１００ 油冷式スクリュ圧縮機
１１１ ロータ室
１３１ 軸孔
１３２ 軸受室
１３４ 軸封部
１３５ 潤滑油回収室
１３６ スペーサ
１３７ 給油溝
１３８’，１３９ ラビリンス溝
１４０，１５０ スクリュロータ
１４０ａ，１５０ａ 吐出側端面（スクリュロータの）
１４１，１４２，１５１，１５２ ロータ軸
１７０ 軸受
１９３ 給油流路
２１０ 駆動源
２２０ レシーバタンク
２２１ 逆止弁
２２２ オイルフィルタ
２２３ オイルクーラ
２２４ 給油配管
Δ 吐出側ロータ軸（スペーサ）の外周面と軸孔の内周面間の隙間
Δ’ ロータ軸の外周面と軸孔の内周面間の隙間

1 Oil-cooled screw compressor 2 Casing 10 Rotor casing 11 Rotor chamber 12 Refueling port 20 Suction side casing 21, 22 Bearing room 23 Gear chamber 24 Intake port 25 Refueling nozzle 30 Discharge side casing 31 Shaft hole 32 Bearing room 33 Discharge port 34 Shaft Seal 35 Lubricating oil recovery chamber 36 Spacer 36a (Spacer) Rotor chamber side 36b (Spacer) Bearing chamber side 37 Refueling groove 38 Labyrinth groove 39 Rectangular labyrinth groove 40 Male screw Rotor 41 Suction side rotor shaft 42 Discharge side rotor shaft 50 Female screw rotor 51 Suction side rotor shaft 52 Discharge side rotor shaft 60,70 Bearing 80 Speed increasing device 81 Drive gear 82 Drive gear 83 Drive shaft 91, 92, 93 Refueling flow Road 94 Lubricating oil recovery flow path 100 Oil-cooled screw compressor 111 Rotor chamber 131 Shaft hole 132 Bearing chamber 134 Shaft seal 135 Lubricating oil recovery chamber 136 Spacer 137 Refueling groove 138', 139 Labyrinth groove 140, 150 Screw rotor 140a, 150a Discharge side end face (of screw rotor)
141, 142, 151,152 Rotor shaft 170 Bearing 193 Oil supply flow path 210 Drive source 220 Receiver tank 221 Check valve 222 Oil filter 223 Oil cooler 224 Oil supply pipe Δ Discharge side rotor shaft (spacer) outer peripheral surface and inside shaft hole Gap between peripheral surfaces Δ'Gap between the outer peripheral surface of the rotor shaft and the inner peripheral surface of the shaft hole

Claims (5)

ケーシング内に形成されたロータ室内にオス，メス一対のスクリュロータを噛み合い状態で回転可能に収容し，前記ケーシングに前記スクリュロータの吐出側ロータ軸を挿入する軸孔と，該軸孔と連通し，前記吐出側ロータ軸を支承する軸受を収納する軸受室とを形成し，前記ロータ室と前記軸受室との間で前記吐出側ロータ軸の外周面と前記軸孔の内周面間の隙間を封止する軸封部を備えた油冷式スクリュ圧縮機の軸封構造において，
前記軸受室と前記ロータ室間の前記吐出側ロータ軸の外周面及び／又は前記吐出側ロータ軸の収容位置における前記軸孔の内周面に，周方向に連続する無端環状の給油溝を形成すると共に，前記ケーシング内に該給油溝に潤滑油を給油する給油流路を設け，
前記軸受室側から前記ロータ室側に向かって徐々に拡大する断面形状を有し，周方向に連続する無端環状のラビリンス溝を，前記給油溝に対し前記ロータ室側に位置する前記吐出側ロータ軸の外周面及び／又は前記軸孔の内周面に，所定間隔で複数平行に設けたことを特徴とする油冷式スクリュ圧縮機の軸封構造。 A pair of male and female screw rotors are rotatably housed in a rotor chamber formed in the casing in a meshed state, and a shaft hole for inserting the discharge side rotor shaft of the screw rotor into the casing and communicating with the shaft hole. , A bearing chamber for accommodating the bearing that supports the discharge side rotor shaft is formed, and a gap between the outer peripheral surface of the discharge side rotor shaft and the inner peripheral surface of the shaft hole between the rotor chamber and the bearing chamber. In the shaft sealing structure of an oil-cooled screw compressor equipped with a shaft sealing part for sealing
An endless annular lubrication groove continuous in the circumferential direction is formed on the outer peripheral surface of the discharge side rotor shaft between the bearing chamber and the rotor chamber and / or on the inner peripheral surface of the shaft hole at the accommodation position of the discharge side rotor shaft. At the same time, a lubrication flow path for supplying lubricating oil to the lubrication groove is provided in the casing.
The discharge side rotor having a cross-sectional shape that gradually expands from the bearing chamber side toward the rotor chamber side and having an endless annular labyrinth groove continuous in the circumferential direction, which is located on the rotor chamber side with respect to the oil supply groove. A shaft sealing structure for an oil-cooled screw compressor, characterized in that a plurality of parallel surfaces are provided on the outer peripheral surface of the shaft and / or the inner peripheral surface of the shaft hole at predetermined intervals. 前記軸受室と前記ロータ室間で前記吐出側ロータ軸に外嵌されて，該位置における前記吐出側ロータ軸の外径を拡大する円筒状のスペーサを設け，該スペーサの外周面を前記吐出側ロータ軸の前記外周面としたことを特徴とする請求項１記載の油冷式スクリュ圧縮機の軸封構造。 A cylindrical spacer is provided between the bearing chamber and the rotor chamber so as to be fitted on the discharge side rotor shaft to expand the outer diameter of the discharge side rotor shaft at the position, and the outer peripheral surface of the spacer is set on the discharge side. The shaft sealing structure of the oil-cooled screw compressor according to claim 1, wherein the outer peripheral surface of the rotor shaft is used. 前記ラビリンス溝を，更に前記給油溝に対し前記軸受室側に位置する前記吐出側ロータ軸の外周面及び／又は前記軸孔の内周面に対しても所定間隔で複数平行に設けたことを特徴とする請求項１又は２記載の油冷式スクリュ圧縮機の軸封構造。 A plurality of labyrinth grooves are provided in parallel with the outer peripheral surface of the discharge side rotor shaft located on the bearing chamber side with respect to the oil supply groove and / or the inner peripheral surface of the shaft hole at predetermined intervals. The shaft sealing structure of the oil-cooled screw compressor according to claim 1 or 2. 断面矩形状を成し，周方向に連続する無端環状の矩形ラビリンス溝を，前記給油溝に対し前記軸受室側に位置する前記吐出側ロータ軸の外周面及び／又は前記軸孔の内周面に所定間隔で複数平行に設けたことを特徴とする請求項１又は２記載の油冷式スクリュ圧縮機の軸封構造。 An endless annular rectangular labyrinth groove having a rectangular cross section and continuous in the circumferential direction is formed on the outer peripheral surface of the discharge side rotor shaft and / or the inner peripheral surface of the shaft hole located on the bearing chamber side with respect to the oil supply groove. The shaft sealing structure of the oil-cooled screw compressor according to claim 1 or 2, wherein a plurality of oil-cooled screw compressors are provided in parallel at predetermined intervals. 前記給油溝に対し前記軸受室側の前記吐出側ロータ軸の外周面と前記軸孔の内周面を，いずれも平滑面としたことを特徴とする請求項１又は２記載の油冷式スクリュ圧縮機の軸封構造。

The oil-cooled screw according to claim 1 or 2, wherein both the outer peripheral surface of the discharge side rotor shaft on the bearing chamber side and the inner peripheral surface of the shaft hole are smooth surfaces with respect to the oil supply groove. Shaft sealing structure of compressor.

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