201013052 六、發明說明： 【發明所屬之技術領域】 本發明是關於使用在冷凍空調等的螺旋壓縮機，特別 是關於實施容量控制的螺旋壓縮機。 【先前技術】 以往的螺旋壓縮機，例如記載於專利文獻1。該螺旋 0 壓縮機，在排出壓力異常上昇的情況，設置於滑閥的釋放 閥會動作，使壓縮氣體旁通至排出側，藉此來減輕施加於 螺旋轉子及支承螺旋轉子的軸承構件之異常負載。 [專利文獻1]日本特開平4-43 883號公報 【發明內容】 上述專利文獻1，是藉由在滑閥設置釋放閥來減輕異 常負載，因此釋放閥必須構成一對的螺旋轉子之膛部的一 Φ 部分，而要求高的加工精度。另外，由於釋放閥是構成由 殼體所形成的壓縮室膛部的一部分，而造成壓縮機變得大 型化。 再者，最近要求將期間成績係數（IPLV )提高’也 要求將螺旋壓縮機的低負載區的性能提高。 本發明的目的是爲了獲得一種可利用簡單的構造來防 止過壓縮之螺旋壓縮機。 本發明的其他目的是爲了獲得一種：藉由提昇在低負 載區的運轉範圍之效率而謀求期間成績係數的提高之螺旋 201013052 壓縮機。 爲了達成上述目的，本發明之螺旋壓縮機，係由具備 公轉子及母轉子之一對的螺旋轉子、及用來收納前述一對 的螺旋轉子之殼體來形成壓縮室，且在前述殻體形成：讓 被壓縮氣體流出的排出口、供從該排出口排出的壓縮氣體 流入之排出室；該螺旋壓縮機的特徵在於：在前述排出口 附近之前述公轉子側及母轉子側雙方之前述殼體，分別設 置使前述壓縮室與前述排出室連通的旁通通路，且設置使 該旁通通路開閉的閥。 在此，使前述旁通通路開閉的閥，能在與前述旁通通 路連通的前述壓縮室的壓力比前述排出室的壓力更高的情 況打開。 另外，前述旁通通路可形成在：與設定容積比 1.5〜3.0、較佳爲1.5〜2.7的範圍內之前述壓縮室連通的位 置。 設置在前述公轉子側或母轉子側之旁通通路’若將複 數個設置在與不同設定容積比的壓縮室連通的位置，效果 更佳。 若將本發明運用在藉由可利用變頻器控制旋轉數的電 動機來驅動前述螺旋轉子的構造’其效果極佳。 本發明的其他特徵之螺旋壓縮機’係由具備公轉子及 母轉子之一對的螺旋轉子、及用來收納前述—對的螺旋轉 子之殻體來形成壓縮室’且在前述殼體形成：讓被壓縮氣 體流出的排出口、供從該排出口排出的壓縮氣體流入之排 -6- 201013052 出室；該螺旋壓縮機的特徵在於：在前述排出口的兩側之 前述殻體，分別設置使前述壓縮室與前述排出室連通的旁 通通路，且設置使該旁通通路開閉的閥。 本發明的再其他特徵之螺旋壓縮機，係包含：具備公 轉子及母轉子之一對的螺旋轉子、用來收納前述一對的螺 旋轉子之主殻體、設置於該主殻體的排出側之排出殼體、 收容有用來驅動前述螺旋轉子的電動機之馬達殼體、設置 Q 於前述主殼體和排出殼體的至少任一方之排出口、由前述 一對的螺旋轉子和前述主殼體所形成之壓縮室、形成於前 述排出殼體而供從前述排出口排出的壓縮氣體流入之排出 室；該螺旋壓縮機的特徵在於：係具備旁通通路及閥；該 旁通通路，是設置在前述排出口附近的前述排出殼體，用 來使前述壓縮室和前述排出室連通；前述閥，是用來使前 述旁通通路開閉，而在與前述旁通通路連通的前述壓縮室 的壓力比前述排出室的壓力低時關閉，且在比前述排出室 φ 的壓力高時打開。 在此，前述旁通通路，可設置在形成於殻體之前述排 出口的公轉子側及母轉子側雙方。 依據本發明的螺旋壓縮機，是在排出口附近的公轉子 側及母轉子側雙方的殻體分別設置使壓縮室與排出室連通 的旁通通路，且設置使該旁通通路開閉的閥，藉此，可獲 得利用簡單的構造即可防止過壓縮之螺旋壓縮機。結果， 可減輕施加於螺旋轉子和支承該轉子的軸承構件之異常負 載，而獲得能防止轉子變形及軸承損傷之高可靠性的螺旋 201013052 壓縮機。 另外，使前述旁通通路開閉的閥，在與旁通通路連通 的壓縮室的壓力比排出室的壓力更高的情況打開，藉此可 防止過壓縮，特別是能提昇在低負載區的運轉範圍的效率 ，因此可謀求期間成績係數的提高。 再者，以連通於不同設定容積比的壓縮室的方式設置 複數個旁通通路，可在廣範圍的運轉區域繼續防止過壓縮 【實施方式】 以下，使用圖式來說明本發明的螺旋壓縮機之具體實 施例。在各圖中，賦予相同符號的部分表示相同或相當的 部分。 [實施例1 ] 第1圖係顯示本發明的實施例1之螺旋壓縮機的縱截 面圖。第1圖所示的螺旋壓縮機，主要是由壓縮機部17 和馬達部18所構成。要被壓縮的氣體（例如流經冷凍循 環的冷媒），是從形成於馬達部18側的馬達外殻16的吸 引口 20被吸引，經過構成馬達（驅動用電動機）22的定 子3和轉子4的部分，進入吸入口 9而藉由一對螺旋轉子 (公轉子2、母轉子2A)所構成的壓縮機部17施以壓縮 。然後，被壓縮的氣體，從排出口 10及徑向排出口 44往 排出室12排出後，流入油分離器80，將油從壓縮氣體分 -8- 201013052 離出，而從排出口 19往壓縮機外排出。 壓縮機部17係具備：內部含有螺旋轉子2、2A 容有滾柱軸承6之主殼體1、用來形成排出室12且 有滾柱軸承7及滾珠軸承8之排出殻體21等。在前 殼體1形成有：吸入口 9、排出口 10及徑向排出口 前述吸引口 20及吸入口 9,是形成流往螺旋轉子2 之吸入流路。前述排出口 10、徑向排出口 44及排出】 φ ，是形成從螺旋轉子2、2A排出的通路。螺旋轉子2 由互相嚙合之一對的公轉子2及母轉子2A(參照第 )所構成，被收納在一對的圓筒狀膛部（第3圖所示 側殼體膛部40a及母側殻體膛部40b)，藉由前述圓 膛部和公轉子2及母轉子2A的嚙合部來形成壓縮室 置在公轉子2的兩側的軸部，是藉由設置在主殻體！ 柱軸承6、設置在排出殻體21的滾柱軸承7及滾珠軸 所支承。 ❹ 馬達部18是包含：馬達外殻16、定子3、轉子 。馬達部18的驅動力是傳遞至壓縮機部17的公轉子 定子3是組裝於馬達外殼16，轉子4是在前述定子 內周側，固定在公轉子2的馬達部側所設的軸部。依 構造’馬達22的驅動力會傳遞至公轉子2，而藉由 子2來驅動母轉子2A。 在上述螺旋壓縮機，爲了調整負載能力，是將來 入壓力感測器（未圖示）的訊號和排出壓力感測器（ 示）的訊號輸入控制裝置（未圖示），藉由變頻器（ 且收 收容 述主 4 4° 、2A t 12 ，是 3圖 的公 A>*S： U41 同狀 。設 的滾 承8 4等 1。 3的 據此 公轉 自吸 未圖 未圖 -9 - 201013052 示）來控制馬達22的旋轉數，藉此調整排出量。若負載 變小而使排出側壓力降低，由公轉子2及母轉子2A所構 成的壓縮室內的被壓縮氣體壓力變得比排出側壓力更高而 造成過壓縮。爲了防止發生此過壓縮，在本實施例，是在 形成壓縮室之排出殻體21設置：使壓縮室和排出室連通 的旁通通路（參照第3圖所示之公側的旁通通路50及母 側的旁通通路51)、以及使該旁通通路開閉的閥110，而 藉由該旁通通路50、51及閥110來進行壓縮室內的壓力 調整。 第2圖係顯示第1圖所示的螺旋轉子（2、2A)部的 任意的壓縮室之容積V和壓力P的關係。圖中，LP代表 吸入壓力，HP2代表滿載運轉時的排出壓力，HP 1代表卸 載運轉時的排出壓力，在吸入壓力LP、排出壓力HP2之 滿載運轉的情況，運轉循環爲al-bl-cl-dl。此外，在吸 入壓力LP、排出壓力HP 1之卸載運轉的情況，且未設置 使壓縮室和排出室連通的旁通通路50、51及閥110的情 況，運轉循環成爲al-bl-g3-fl-dl，而el-bl-g3成爲不必 要壓縮的過壓縮區域。在本實施例，藉由設置旁通通路 50、51及閥110，能使運轉循環成爲al-el-fl-dl，而防 止無益的過壓縮。 旁通通路50、51的設置位置可根據以下方式來決定 。亦即，旁通通路50、51，只要在卸載運轉時，當經由 公轉子和母轉子的嚙合所形成的壓縮室的壓力P成爲排出 壓力HP1時，形成在能使該壓縮室和排出室12連通的位 -10- 201013052 置即可。因此，首先，根據從吸入壓力LP到變成卸載運 轉時的任意的排出壓力HP 1時的設定容積比Vi201013052 SUMMARY OF THE INVENTION Technical Field The present invention relates to a screw compressor used in a refrigerating air conditioner or the like, and more particularly to a screw compressor that performs capacity control. [Prior Art] A conventional screw compressor is described, for example, in Patent Document 1. In the spiral zero compressor, when the discharge pressure abnormally rises, the release valve provided in the spool operates to bypass the compressed gas to the discharge side, thereby reducing the abnormality of the bearing member applied to the spiral rotor and the support spiral rotor. load. [Patent Document 1] Japanese Laid-Open Patent Publication No. Hei-4-43 883. SUMMARY OF THE INVENTION In the above Patent Document 1, since the abnormal load is reduced by providing a release valve on the spool, the release valve must constitute a pair of helical rotors. A Φ part requires high machining accuracy. Further, since the relief valve constitutes a part of the compression chamber portion formed by the casing, the compressor becomes large. Furthermore, the recent increase in the period performance factor (IPLV) has also required an increase in the performance of the low load region of the screw compressor. SUMMARY OF THE INVENTION An object of the present invention is to obtain a screw compressor which can be prevented from being over-compressed with a simple configuration. Another object of the present invention is to obtain a spiral 201013052 compressor that improves the performance coefficient of the period by increasing the efficiency of the operating range in the low load zone. In order to achieve the above object, a screw compressor according to the present invention comprises a spiral rotor having a pair of a male rotor and a female rotor, and a casing for accommodating the pair of spiral rotors to form a compression chamber, and the housing is Forming a discharge port through which the compressed gas flows out, and a discharge chamber through which the compressed gas discharged from the discharge port flows; the screw compressor is characterized in that the both the male rotor side and the female rotor side in the vicinity of the discharge port are formed The casing is provided with a bypass passage that communicates the compression chamber with the discharge chamber, and a valve that opens and closes the bypass passage. Here, the valve that opens and closes the bypass passage can be opened when the pressure of the compression chamber that communicates with the bypass passage is higher than the pressure of the discharge chamber. Further, the bypass passage may be formed at a position communicating with the compression chamber in a range of a set volume ratio of 1.5 to 3.0, preferably 1.5 to 2.7. The bypass passages provided on the male rotor side or the female rotor side are more effective if a plurality of bypass passages are provided in communication with the compression chambers of different set volume ratios. The present invention is excellent in the use of the present invention to drive the structure of the spiral rotor by a motor that can control the number of revolutions by the frequency converter. A screw compressor of another feature of the present invention is formed by a spiral rotor having a pair of a male rotor and a female rotor, and a casing for accommodating the aforementioned pair of helical rotors to form a compression chamber' and formed in the casing: The discharge port through which the compressed gas flows out and the compressed gas discharged from the discharge port flow into the row -6-201013052 out of the chamber; the screw compressor is characterized in that the casings on both sides of the discharge port are respectively provided A bypass passage that communicates the compression chamber with the discharge chamber and a valve that opens and closes the bypass passage. A screw compressor according to still another aspect of the present invention includes: a spiral rotor including one pair of a male rotor and a female rotor; a main casing for accommodating the pair of spiral rotors; and a discharge side provided on the main casing a discharge case, a motor case in which an electric motor for driving the spiral rotor is housed, a discharge port provided in at least one of the main case and the discharge case, and a pair of spiral rotors and the main case a compression chamber formed, a discharge chamber formed in the discharge casing and containing compressed gas discharged from the discharge port; the screw compressor is characterized in that: a bypass passage and a valve are provided; the bypass passage is provided The discharge casing in the vicinity of the discharge port is for communicating the compression chamber and the discharge chamber; the valve is for opening and closing the bypass passage, and the pressure of the compression chamber communicating with the bypass passage It is closed when the pressure of the discharge chamber is lower, and is opened when the pressure of the discharge chamber φ is higher. Here, the bypass passage may be provided on both the male rotor side and the female rotor side formed at the discharge port of the casing. According to the screw compressor of the present invention, the housings on both the male rotor side and the female rotor side in the vicinity of the discharge port are provided with bypass passages for communicating the compression chamber and the discharge chamber, and a valve for opening and closing the bypass passage is provided. Thereby, a screw compressor capable of preventing over-compression with a simple configuration can be obtained. As a result, the abnormal load applied to the spiral rotor and the bearing member supporting the rotor can be alleviated, and a highly reliable spiral 201013052 compressor capable of preventing deformation of the rotor and bearing damage can be obtained. Further, the valve that opens and closes the bypass passage is opened when the pressure of the compression chamber that communicates with the bypass passage is higher than the pressure of the discharge chamber, thereby preventing over-compression, and in particular, improving operation in a low load region. The efficiency of the range, so the coefficient of performance during the period can be improved. Further, by providing a plurality of bypass passages so as to communicate with the compression chambers having different set volume ratios, over-compression can be prevented in a wide range of operation regions. [Embodiment] Hereinafter, the screw compressor of the present invention will be described using the drawings. Specific embodiment. In the respective drawings, the same reference numerals are given to the same or equivalent parts. [Embodiment 1] Fig. 1 is a longitudinal cross-sectional view showing a screw compressor of Embodiment 1 of the present invention. The screw compressor shown in Fig. 1 is mainly composed of a compressor unit 17 and a motor unit 18. The gas to be compressed (for example, the refrigerant flowing through the refrigeration cycle) is sucked from the suction port 20 of the motor casing 16 formed on the motor portion 18 side, and passes through the stator 3 and the rotor 4 constituting the motor (driving motor) 22. The portion that enters the suction port 9 is compressed by the compressor portion 17 composed of a pair of spiral rotors (the male rotor 2 and the female rotor 2A). Then, the compressed gas is discharged from the discharge port 10 and the radial discharge port 44 to the discharge chamber 12, and then flows into the oil separator 80 to separate the oil from the compressed gas -8-201013052 and to compress from the discharge port 19. Discharged outside the machine. The compressor unit 17 includes a main casing 1 in which the spiral rotor 2, 2A accommodates the roller bearing 6, a discharge casing 12 in which the discharge chamber 12 is formed, a roller bearing 7 and a ball bearing 8, and the like. The front casing 1 is formed with a suction port 9, a discharge port 10, and a radial discharge port. The suction port 20 and the suction port 9 form a suction flow path to the spiral rotor 2. The discharge port 10, the radial discharge port 44, and the discharge φ are passages formed from the spiral rotors 2, 2A. The spiral rotor 2 is composed of a male rotor 2 and a female rotor 2A (see the first) that are in mesh with each other, and is housed in a pair of cylindrical jaws (the side housing flange portion 40a and the mother side shown in Fig. 3). The casing crotch portion 40b) is formed by the engagement portion of the round crotch portion and the male rotor 2 and the female rotor 2A to form a shaft portion of the compression chamber which is disposed on both sides of the male rotor 2, and is provided in the main casing! The column bearing 6, the roller bearing 7 provided in the discharge casing 21, and the ball shaft are supported.马达 The motor unit 18 includes a motor housing 16, a stator 3, and a rotor. The driving force of the motor unit 18 is the male rotor that is transmitted to the compressor unit 17. The stator 3 is assembled to the motor casing 16, and the rotor 4 is fixed to the shaft portion of the male rotor 2 on the motor inner side of the stator. The driving force of the motor 22 is transmitted to the male rotor 2, and the female rotor 2A is driven by the sub-2. In order to adjust the load capacity, the above-mentioned screw compressor is a signal input control device (not shown) for inputting a pressure sensor (not shown) and a discharge pressure sensor (not shown) in the future, by a frequency converter ( And accept the main 4 4 °, 2A t 12, is the 3 figure of the public A > * S: U41 with the same shape. Set the rolling bearing 8 4 and so on 1. 3 according to this revolution, self-priming is not shown Figure 9 - 201013052 shows) to control the number of rotations of the motor 22, thereby adjusting the discharge amount. When the load is reduced and the pressure on the discharge side is lowered, the pressure of the compressed gas in the compression chamber formed by the male rotor 2 and the female rotor 2A becomes higher than that on the discharge side to cause over-compression. In order to prevent this over-compression, in the present embodiment, the discharge casing 21 forming the compression chamber is provided with a bypass passage that communicates the compression chamber and the discharge chamber (refer to the bypass passage 50 on the male side shown in Fig. 3). And the bypass passage 51) on the mother side and the valve 110 that opens and closes the bypass passage, and the pressure adjustment in the compression chamber is performed by the bypass passages 50, 51 and the valve 110. Fig. 2 is a view showing the relationship between the volume V and the pressure P of an arbitrary compression chamber of the spiral rotor (2, 2A) shown in Fig. 1. In the figure, LP represents the suction pressure, HP2 represents the discharge pressure at full load operation, HP 1 represents the discharge pressure during the unloading operation, and in the case of the full load operation of the suction pressure LP and the discharge pressure HP2, the operation cycle is al-bl-cl- Dl. Further, in the case of the unloading operation of the suction pressure LP and the discharge pressure HP1, and the bypass passages 50, 51 and the valve 110 that communicate the compression chamber and the discharge chamber are not provided, the operation cycle becomes al-bl-g3-fl. -dl, and el-bl-g3 becomes an over-compressed area that is not necessarily compressed. In the present embodiment, by providing the bypass passages 50, 51 and the valve 110, the operation cycle can be made a-el-fl-dl, and unhelpful over-compression can be prevented. The installation position of the bypass passages 50, 51 can be determined in the following manner. That is, the bypass passages 50, 51 are formed such that the compression chamber and the discharge chamber 12 can be formed when the pressure P of the compression chamber formed by the engagement of the male rotor and the female rotor becomes the discharge pressure HP1 during the unloading operation. Connected bits -10- 201013052 can be set. Therefore, first, the set volume ratio Vi according to the arbitrary discharge pressure HP 1 from the suction pressure LP to the unloading operation
Vi = (HPl/LP)1/n 來求出壓縮室容積VD1Vi = (HPl/LP)1/n to find the compression chamber volume VD1
VD1 =VT/Vi 而在形成該壓縮室容積VD1的螺旋轉子的旋轉角位置設 置前述旁通通路50、51即可。 在上式中， η:每個冷媒的多態指數（politropicindex) VT :吸入容積（轉子的最大空間容積） φ 亦即，只要決定吸入壓力LP、排出室的排出壓力 HP1等的運轉條件，即可決定設定容積比Vi，因此對於 卸載運轉時任意的排出壓力HP 1求出壓縮室容積VD1’ 而決定出對應於該壓縮室容積VD1之公轉子2及母轉子 2A的旋轉角，即能以與該旋轉角的壓縮室連通的方式設 定前述旁通通路50、51。 第3圖係顯示第1圖所示的螺旋壓縮機的A-A線截 面圖（排出口部）。若藉由馬達使公轉子2旋轉，與公轉 子2嚙合的母轉子2A也會旋轉，而將被壓縮氣體封閉在 -11 - 201013052 壓縮室。公側的壓縮室3 0a是由公側殻體膛部40a和公轉 子2所形成；母側的壓縮室30b是由母側殼體膛部40b和 母轉子2A所形成。而且公側的壓縮室30a和母側的壓縮 室30b也是連通的。 第3(A)圖係顯示設置在排出殼體21之旁通通路 50的開放時或剛開放後的螺旋轉子旋轉位置。公側的旁 通通路50，只要設置成能與所決定的旋轉角之公轉子2 的後進面切線120接觸即可。另外，母側的旁通通路51 ，只要設置成能與所決定的旋轉角之母轉子2A的後進面 切線123接觸即可。 前述旁通通路50、51之孔的大小，是設置成公轉子 及母轉子的最小齒厚以下，以避免相鄰的壓縮室彼此連通 〇 第3(B)圖係顯示旁通通路50、51全開時或剛全開 後的螺旋轉子旋轉位置。被壓縮氣體，在開始從公側排出 口 42及母側排出口 43排出前的期間，是從前述旁通通路 50、51繼續旁通至排出室12。 第3(C)圖係顯示，壓縮室3 0a、3 0b的被壓縮氣體 開始從設置於排出殼體21的公側排出口 42及母側排出口 43往排出室12排出時之螺旋轉子旋轉位置。 第4圖係顯示第1圖所示的螺旋壓縮機之公側旁通通 路50上所設的閥110部分的截面圖。如圖所示，排出室 12的壓力是透過排出通路1〇〇而作用在閥通路115內， 若旁通通路50內的壓力比閥通路115內的壓力更高，閥 -12- 201013052 110會被壓力差往上推，壓縮室3 0a內的被壓縮氣體會通 過閥通路115而往排出室12排出。 在母側旁通通路51也是具有相同的構造。 第5圖係第4圖的B-B線截面圖。藉由彈簧112而始 終朝關閉閥110的方向施加彈力於閥110。來自旁通通路 5〇側而作用於閥110的閥部116之氣體壓力，若超過作 用於閥通路115內之排出室12的氣體壓力和前述彈力的 β 合計値，閥110會打開，而使壓縮室3 0a內的過壓縮氣體 流往排出室1 2。 第5圖中，111代表油孔，113代表保持閥110的凸 緣，該凸緣113是透過螺絲114來安裝於排出殼體21。 第6圖係第3圖所示的實施例之變形例，是相當於第 3圖。在本例，公側的旁通通路50最初是打開的，使壓 縮室30a的過壓縮氣體旁通而排出至排出室，接著母側的 旁通通路51打開而同樣地使壓縮室30b的過壓縮氣體往 ❹排出室排出。 在第6 ( A )圖，將公側的旁通通路5 0和母側的旁通 通路51設定成能在一定區間重疊而開口的位置，如此可 廣範圍地繼續防止過壓縮。在第6(B)圖的例子，是將 旁通通路50和51的開口區間偏置成不發生重疊，以這種 方式來設定旁通通路亦可。 第7圖係第3圖所示的實施例之變形例，是將第3圖 的排出口 10附近放大顯示。在第7(A)圖所示的例子， 是僅在公側設置旁通通路50’在母轉子的齒厚薄而無法 -13- 201013052 設置較大的母側旁通通路的情況，僅在公側設置旁通通路 亦可。本例中，不須在母側設置旁通通路和閥，可降低成 本。又在第7(B)圖所示的例子在公側未設置旁通通路 而僅在母側設置旁通通路51亦可。又雖未圖示出，但在 公側和母側分別設置旁通通路，且讓公側旁通通路的開口 面積比母側旁通通路的開口面積更大的構造也是有效的。 第8圖係第3圖所示的實施例之其他變形例，是將第 3圖的排出口 10附近放大顯示。在第8(A)圖所示的例 φ 子，設置在排出殼體之旁通通路50、51是由長孔所形成 ，依據此構造，可充分確保旁通通路的旁通流路面積，而 能減低從旁通通路往排出室旁通之壓縮氣體的流路阻力。 在第8(B)圖所示的例子，是在任意的不同設定容 積比的位置分別設置複數個公側旁通通路50、50a、母側 旁通通路5 1、5 1 a。在本例，在公轉子側和母轉子側，雖 是分別在2個不同的任意設定容積比的位置設置旁通通路 ，但也能在3個以上不同的任意設定容積比的位置設置旁 @ 通通路。又在本例，設置在任意相同設定容積比的位置的 旁通通路，雖是分別由2個孔所形成，但也能由3個以上 的孔所形成。如本例般，藉由複數個孔來形成旁通通路， 相較於第8(A)圖所示的例子，加工變容易，而能縮短 加工時間。 第9圖及第10圖，是在設置於第8(B)圖所示的排 出口部附近的旁通通路 50、50a、51、51a分別設置平板 彈簧式閥70和閥推桿71，是相當於第1圖的排出口部附 -14- 201013052 近之F-F線截面圖。第10圖係第9圖所示的閥部的D-D 線截面圖。如本例所示，在使壓縮室和排出室連通的旁通 通路的排出室側，藉由螺栓73將平板彈簧式閥70和閥推 桿71 —起鎖緊安裝在主殻體1，可減少閥機構的製造工 時，可簡化閥構造，而謀求閥的成本降低。另外，用來使 旁通通路開閉的閥是採用平板彈簧式的閥，藉此在有限的 狹小空間可設置複數個閥。 〇 另外，在第1圖〜第7圖所示的例子，使旁通通路開 閉的閥也能採用平板彈簧式的閥。 第11圖、第12圖係第4圖、第5圖所示的例子之其 他實施形態。在第4圖，是將閥110沿縱向（與軸向垂直 的方向）設置，在第11圖、第12圖的例子，是將閥110 沿橫向（軸向）設置的例子。第12圖係從第1 1圖的C-C 線方向視觀察的閥部附近的截面圖。在第11圖、第12圖 中，與第4圖、第5圖賦予相同符號的部分，是表示相同 Ο 或相當的部分。如本例所示，藉由將閥110橫向設置，能 使旁通通路50 (用來使壓縮室和排出室連通）的長度比 第4圖、第5圖所示的例子更短，可抑制體積效率的降低 。在第12圖，117代表間隔件，是相當於第5圖的凸緣 113° 第13圖係第11圖、第12圖所示的例子之其他例， 是相當於第12圖的部分之截面圖。在本例，來自油槽25 之高壓油是經過配管141導入閥汽缸143，而利用油壓來 使閥140 (用來開閉旁通通路50)動作。利用高壓的油壓 -15- 201013052 ，可將閥140推壓到堵住旁通通路50及排出通路100的 位置。在旁通通路50(用來連通壓縮室和排出室12)的 壓力比油壓更大的情況，是透過配管141將汽缸143內的 高壓油推回油槽25，使閥140往圖的右方動作，而透過 旁通通路50及排出通路100使被壓縮氣體往排出室12旁 通。 第14圖、第15圖係第11圖、第12圖所示的例子之 再其他例子，第14圖係相當於第12圖的部分之截面圖’ 第15圖係從第14圖的E-E線方向觀察之閥部附近的截面 圖。在本例，是在旁通通路50 (用來連通壓縮室和排出 室12)的途中設置閥135(在圓柱中心設有孔），藉由步 進馬達131透過軸134使該閥135如第15圖所示例如轉 動90度，以進行旁通通路50的開閉。步進馬達131的控 制，是將來自設置於旁通通路50(用來連通壓縮室和排 出室）的壓力感測器1 3 3、設置於排出室1 2之壓力感測 器133的訊號輸入控制裝置132，在旁通通路50的壓力 比排出室12的壓力更大的情況，使閥135成爲開狀態， 在旁通通路50的壓力比排出室12的壓力更小的情況，使 閥135成爲閉狀態。依據本例，是構成容易追隨壓縮室的 壓力變化之閥機構。 第16圖係第11圖、第12圖所示的例子之再其他例 子，是相當於第12圖或第14圖的部分之截面圖。在本例 ，是在旁通通路50 (用來連通壓縮室和排出室）的途中 設置電磁閥136，藉由控制裝置132，與第14圖所示的例 -16- 201013052 子同樣的，根據旁通通路50的壓力和排出室12的壓力來 控制電磁閥136。藉由打開電磁閥136，能使壓縮室的壓 縮氣體透過旁通通路50及排出通路100而往排出室12旁 通。在本例，不須使用複雜的閥開閉機構，即可與第14 圖所示的例子同樣的構成容易追隨壓縮室的壓力變化之閥 機構。 依據以上所說明的實施例，藉由在排出口附近設置使 0 壓縮室和排出室連通的旁通通路，且設置使該旁通通路開 閉的閥，可維持壓縮室內的被壓縮氣體或將其朝排出室排 出，在壓縮室壓力比排出室壓力更高的情況，藉由打開旁 通通路，可抑制在壓縮室發生過壓縮。特別是在低壓縮比 運轉時，壓縮室的壓力容易被過壓縮至排出室側的運轉壓 力以上，若壓縮室的壓力成爲排出室側壓力以上，旁通通 路的閥打開，而使壓縮室內的壓縮氣體透過旁通通路往排 出室側排出。因此，可防止過壓縮運轉，減低壓縮機的軸 φ 動力，特別是提昇低壓縮比運轉區的性能。結果，可減輕 施加於軸承構件及螺旋轉子之異常負載，而防止轉子變形 和軸承損傷。 另外，將前述旁通通路設置在設定容積比1.5~3.0、 較佳爲1·5~2.7的範圍內，並設置使該旁通通路開閉的閥 ，藉此能獲得卸載運轉時的最佳運轉。再者’將旁通通路 (用來連通壓縮室和排出室）設置在公轉子側及母轉子側 雙方，可高效率地使壓縮室的被壓縮氣體往排出室流出。 再者，將前述旁通通路（用來連通壓縮室和排出室） -17- 201013052 分別設置在與不同設定容積比的壓縮室連通的位置，能在 更廣的範圍防止卸載運轉時的過壓縮。另外，若旁通通路 是由複數個孔所形成，可減低旁通通路的流路阻力，且能 將旁通通路整體的容積縮小，因此可減少旁通通路所產生 之非壓縮容積，而能抑制體積效率的降低。 【圖式簡單說明】 第1圖係本發明的實施例1之螺旋壓縮機的縱截面圖 〇 第2圖係顯示第1圖所示的螺旋轉子部的任意的壓縮 室之容積V和壓力P的關係。 第3圖係顯示第1圖所示的螺旋壓縮機的A-A線截 面圖；第3(A)圖係顯示設置在排出殻體之旁通通路的 開放時或剛開放後的螺旋轉子旋轉位置；第3(B)圖係 顯示旁通通路全開時或剛全開後的螺旋轉子旋轉位置；第 3 (C)圖係顯示，壓縮室的被壓縮氣體開始從設置於排出 殼體的公側排出口及母側排出口往排出室排出時之螺旋轉 子旋轉位置。 第4圖係顯示第1圖所示的螺旋壓縮機之公側旁通通 路上所設的閥部分的截面圖。 第5圖係第4圖的B-B線截面圖。 第6(A) (B)圖係第3圖所示的實施例之2個變形 例，是將第3圖的排出口附近放大顯示。 第7(A) (B)圖係第3圖所示的實施例之另外2個 -18- 201013052 變形例，是將第3圖的排出口附近放大顯示。 第8(A) (B)圖係第3圖所示的實施例之再另外2 個變形例，是將第3圖的排出口附近放大顯示。 第9圖是在設置於第8(B)圖所示的排出口部附近 的旁通通路分別設置平板彈簧式閥和閥推桿的圖，是相當 於第1圖之F-F線截面圖。 第10圖係第9圖所示的閥部的D-D線截面圖。 φ 第Π圖係第4圖所示例的其他實施形態，是相當於 第4圖。 第12圖係從第11圖的C-C線方向觀察的閥部附近的 截面圖。 第13圖係第1 1圖、第12圖所示的例之其他例，是 相當於第12圖部分的截面圖。 第14圖係第11圖、第12圖所示的例之再其他例， 是相當於第12圖部分的截面圖。 〇 第15圖係從第14圖的E-E線方向觀察的閥部附近的 截面圖。 第16圖係第11圖、第12圖所示的例之再其他例’ 是相當於第12圖或第14圖部分的截面圖。 【主要元件符號說明】 1 '·主殻體 2 :公轉子 2 A :母轉子 -19- 201013052 3 :定子 4 :轉子 6、7 :滾柱軸承 8 :滾珠軸承 9 :吸入口 1 0 :排出口 1 2 :排出室 15 :端蓋 瘳 1 6 :馬達殼體 17 :壓縮機部 1 8 :馬達部 1 9 :排出口 20 :吸引口 2 1 :排出殼體 22 :馬達 25 :油槽 @ 26、73 :螺栓 30a、30b :壓縮室 40a :公側殼體膛部 40b :母側殼體膛部 42 :公側排出口 4 3 :母側排出口 44 :徑向排出口 50、50a、51、51a:旁通通路 -20- 201013052 70 :閥 7 1 :閥推桿 80 :油分離器 100 :排出通路 1 1 0、1 3 5、1 4 0 :閥（開閉閥） Π 1 :油孔 1 12 :彈簧 φ 113 、 142 :凸緣 1 1 4 :螺絲 1 1 5 :閥通路 1 1 6 :閥部 1 1 7 :間隔件 120 :公轉子後進面切線 123 :母轉子後進面切線 1 3 1 :步進馬達 φ 1 3 2 :控制裝置 133 :壓力感測器 134 :軸 1 3 6 :電磁閥 1 4 1 :油配管 143 :汽缸VD1 = VT/Vi, and the bypass passages 50, 51 may be provided at the rotational angular position of the spiral rotor forming the compression chamber volume VD1. In the above formula, η: the politropic index of each refrigerant VT : the suction volume (the maximum space volume of the rotor) φ, that is, the operating conditions such as the suction pressure LP and the discharge pressure HP1 of the discharge chamber, that is, Since the volume ratio Vi can be determined, the compression chamber volume VD1' can be obtained for the discharge pressure HP 1 at the time of the unloading operation, and the rotation angle of the male rotor 2 and the female rotor 2A corresponding to the compression chamber volume VD1 can be determined. The bypass passages 50, 51 are set in such a manner as to communicate with the compression chamber of the rotation angle. Fig. 3 is a cross-sectional view taken along line A-A of the screw compressor shown in Fig. 1 (discharge port portion). When the male rotor 2 is rotated by the motor, the female rotor 2A engaged with the male rotor 2 is also rotated, and the compressed gas is enclosed in the compression chamber of -11 - 201013052. The compression chamber 30a on the male side is formed by the male side casing portion 40a and the male rotor 2; the compression chamber 30b on the female side is formed by the female side casing portion 40b and the female rotor 2A. Further, the compression chamber 30a on the male side and the compression chamber 30b on the female side are also in communication. The third (A) diagram shows the spiral rotor rotational position which is provided at the time of opening or immediately after the bypass passage 50 of the discharge casing 21. The bypass passage 50 on the male side may be provided so as to be in contact with the tangential line 120 of the trailing surface of the male rotor 2 of the determined rotation angle. Further, the bypass passage 51 on the female side may be provided so as to be in contact with the trailing surface tangential line 123 of the female rotor 2A having the determined rotation angle. The sizes of the holes of the bypass passages 50, 51 are set to be equal to or less than the minimum tooth thickness of the male and female rotors to prevent adjacent compression chambers from communicating with each other. The third (B) diagram shows the bypass passages 50, 51. Rotary rotor rotation position when fully open or just after full opening. The compressed gas is continuously bypassed from the bypass passages 50, 51 to the discharge chamber 12 before the discharge from the male discharge port 42 and the female discharge port 43 is started. The third (C) diagram shows the spiral rotor rotation when the compressed gas of the compression chambers 30a and 30b starts to be discharged from the male side discharge port 42 and the mother side discharge port 43 of the discharge casing 21 to the discharge chamber 12. position. Fig. 4 is a cross-sectional view showing a portion of the valve 110 provided on the male bypass passage 50 of the screw compressor shown in Fig. 1. As shown, the pressure in the discharge chamber 12 acts through the discharge passage 1 in the valve passage 115. If the pressure in the bypass passage 50 is higher than the pressure in the valve passage 115, the valve -12-201013052 110 When the pressure difference is pushed up, the compressed gas in the compression chamber 30a is discharged to the discharge chamber 12 through the valve passage 115. The female bypass passage 51 also has the same configuration. Fig. 5 is a cross-sectional view taken along line B-B of Fig. 4. An elastic force is applied to the valve 110 in the direction of closing the valve 110 by the spring 112. When the gas pressure from the valve portion 116 of the valve 110 from the side of the bypass passage 5 exceeds the gas pressure of the discharge chamber 12 acting in the valve passage 115 and the above-described elastic force β, the valve 110 is opened, and the valve 110 is opened. The over-compressed gas in the compression chamber 30a flows to the discharge chamber 12. In Fig. 5, 111 denotes an oil hole, 113 denotes a flange of the holding valve 110, and the flange 113 is attached to the discharge casing 21 via a screw 114. Fig. 6 is a modification of the embodiment shown in Fig. 3, which corresponds to Fig. 3. In this example, the bypass passage 50 on the male side is initially opened, bypassing the compressed gas of the compression chamber 30a and discharging it to the discharge chamber, and then the bypass passage 51 on the female side is opened to similarly pass the compression chamber 30b. The compressed gas is discharged to the discharge chamber. In the sixth (A) diagram, the bypass passage 50 on the male side and the bypass passage 51 on the female side are set to be positions that can be overlapped and opened in a certain section, so that over-compression can be continuously prevented in a wide range. In the example of Fig. 6(B), the opening intervals of the bypass passages 50 and 51 are offset so as not to overlap, and the bypass passage may be set in this manner. Fig. 7 is a modification of the embodiment shown in Fig. 3, which is an enlarged view of the vicinity of the discharge port 10 of Fig. 3. In the example shown in Fig. 7(A), it is only the case where the bypass passage 50' is provided on the male side, and the female rotor has a small tooth thickness and cannot provide a large female bypass bypass path from -13 to 201013052. The bypass passage may be provided on the side. In this case, it is not necessary to provide bypass passages and valves on the female side to reduce costs. Further, in the example shown in Fig. 7(B), the bypass passage is not provided on the male side, and the bypass passage 51 may be provided only on the female side. Further, although not shown, it is also effective to provide a bypass passage on the male side and the female side, and to make the opening area of the male bypass passage larger than the opening area of the female bypass passage. Fig. 8 is a view showing another modification of the embodiment shown in Fig. 3, which is an enlarged view of the vicinity of the discharge port 10 of Fig. 3. In the example φ shown in Fig. 8(A), the bypass passages 50, 51 provided in the discharge casing are formed by long holes, and according to this configuration, the bypass passage area of the bypass passage can be sufficiently ensured. The flow path resistance of the compressed gas bypassing the bypass passage to the discharge chamber can be reduced. In the example shown in Fig. 8(B), a plurality of male side bypass passages 50, 50a and mother side bypass passages 5 1 and 5 1 a are provided at positions of arbitrary different setting volume ratios. In this example, the bypass passage is provided at the position of the two different arbitrary set volume ratios on the male rotor side and the female rotor side. However, it is also possible to set the bypass passage at three or more different arbitrary set volume ratio positions. Through path. Further, in this example, the bypass passages provided at positions of the same set volume ratio are formed by two holes, but they may be formed by three or more holes. As in this example, the bypass passage is formed by a plurality of holes, and the machining becomes easier as compared with the example shown in Fig. 8(A), and the machining time can be shortened. In the ninth and tenth drawings, the flat spring valve 70 and the valve pusher 71 are provided in the bypass passages 50, 50a, 51, and 51a provided in the vicinity of the discharge port portion shown in Fig. 8(B), respectively. Corresponding to the discharge port of Figure 1 attached to the section -14-201013052 near the FF line cross-sectional view. Fig. 10 is a cross-sectional view taken along line D-D of the valve portion shown in Fig. 9. As shown in this example, the flat spring valve 70 and the valve push rod 71 are locked and mounted on the main casing 1 by the bolts 73 on the discharge chamber side of the bypass passage that connects the compression chamber and the discharge chamber. Reducing the manufacturing man-hour of the valve mechanism simplifies the valve structure and reduces the cost of the valve. Further, the valve for opening and closing the bypass passage is a flat spring type valve, whereby a plurality of valves can be provided in a limited narrow space. 〇 In addition, in the example shown in Figs. 1 to 7, a flat spring type valve can be used for the valve that opens and closes the bypass passage. Fig. 11 and Fig. 12 show other embodiments of the examples shown in Figs. 4 and 5. In Fig. 4, the valve 110 is disposed in the longitudinal direction (direction perpendicular to the axial direction), and in the examples of Figs. 11 and 12, the valve 110 is disposed in the lateral direction (axial direction). Fig. 12 is a cross-sectional view showing the vicinity of the valve portion as seen from the direction of the C-C line of Fig. 11. In the eleventh and twelfthth drawings, the portions denoted by the same reference numerals as those in Figs. 4 and 5 denote the same or equivalent portions. As shown in this example, by arranging the valve 110 laterally, the length of the bypass passage 50 (for connecting the compression chamber and the discharge chamber) can be made shorter than the examples shown in Figs. 4 and 5, and can be suppressed. Reduced volumetric efficiency. In Fig. 12, reference numeral 117 denotes a spacer which is equivalent to the flange 113 of Fig. 5 and another example of the example shown in Fig. 11 and Fig. 12, which is a section corresponding to the portion of Fig. 12. Figure. In this example, the high-pressure oil from the oil groove 25 is introduced into the valve cylinder 143 through the pipe 141, and the valve 140 (for opening and closing the bypass passage 50) is operated by the hydraulic pressure. With the high pressure oil pressure -15-201013052, the valve 140 can be pushed to a position blocking the bypass passage 50 and the discharge passage 100. When the pressure of the bypass passage 50 (for connecting the compression chamber and the discharge chamber 12) is larger than the oil pressure, the high pressure oil in the cylinder 143 is pushed back to the oil groove 25 through the pipe 141, and the valve 140 is turned to the right of the figure. In operation, the compressed gas is bypassed to the discharge chamber 12 through the bypass passage 50 and the discharge passage 100. Fig. 14 and Fig. 15 are still other examples of the examples shown in Fig. 11 and Fig. 12, and Fig. 14 is a cross-sectional view corresponding to the portion of Fig. 12'. Fig. 15 is the EE line from Fig. 14. A cross-sectional view of the vicinity of the valve portion in the direction of observation. In this example, a valve 135 (a hole is provided in the center of the cylinder) is provided in the middle of the bypass passage 50 (for connecting the compression chamber and the discharge chamber 12), and the valve 135 is passed through the shaft 134 by the stepping motor 131. As shown in Fig. 15, for example, the rotation is 90 degrees to open and close the bypass passage 50. The control of the stepping motor 131 is to input a signal from a pressure sensor 133 provided in the bypass passage 50 (for connecting the compression chamber and the discharge chamber) and a pressure sensor 133 provided in the discharge chamber 12. The control device 132 opens the valve 135 when the pressure of the bypass passage 50 is larger than the pressure of the discharge chamber 12, and causes the valve 135 to be smaller when the pressure of the bypass passage 50 is smaller than the pressure of the discharge chamber 12. Become closed. According to this example, it is a valve mechanism that constitutes a pressure change that easily follows the compression chamber. Fig. 16 is a cross-sectional view showing a portion corresponding to Fig. 12 or Fig. 14 in still another example of Figs. 11 and 12. In this example, the solenoid valve 136 is provided in the middle of the bypass passage 50 (for connecting the compression chamber and the discharge chamber), and the control device 132 is the same as the example-16-201013052 shown in FIG. The pressure of the bypass passage 50 and the pressure of the discharge chamber 12 control the solenoid valve 136. By opening the solenoid valve 136, the compressed gas in the compression chamber can be bypassed through the bypass passage 50 and the discharge passage 100 to the discharge chamber 12. In this example, the valve mechanism which is easy to follow the pressure change of the compression chamber can be constructed in the same manner as the example shown in Fig. 14 without using a complicated valve opening and closing mechanism. According to the embodiment described above, by providing a bypass passage that connects the zero compression chamber and the discharge chamber in the vicinity of the discharge port, and providing a valve that opens and closes the bypass passage, the compressed gas in the compression chamber can be maintained or The discharge chamber is discharged, and when the compression chamber pressure is higher than the discharge chamber pressure, by opening the bypass passage, over-compression in the compression chamber can be suppressed. In particular, in the low compression ratio operation, the pressure in the compression chamber is easily compressed to the operating pressure on the discharge chamber side. If the pressure in the compression chamber becomes equal to or higher than the discharge chamber side pressure, the valve of the bypass passage opens, and the compression chamber is opened. The compressed gas is discharged to the discharge chamber side through the bypass passage. Therefore, the over-compression operation can be prevented, the shaft φ power of the compressor can be reduced, and in particular, the performance of the low compression ratio operating region can be improved. As a result, the abnormal load applied to the bearing member and the spiral rotor can be alleviated, and the rotor deformation and bearing damage can be prevented. Further, the bypass passage is provided in a range of a setting volume ratio of 1.5 to 3.0, preferably 1.5 to 2.7, and a valve for opening and closing the bypass passage is provided, whereby optimum operation during the unloading operation can be obtained. . Further, the bypass passage (for connecting the compression chamber and the discharge chamber) is provided on both the male rotor side and the female rotor side, and the compressed gas in the compression chamber can be efficiently discharged to the discharge chamber. Furthermore, the aforementioned bypass passages (for connecting the compression chamber and the discharge chamber) -17-201013052 are respectively disposed at positions communicating with the compression chambers of different set volume ratios, and can prevent over-compression during the unloading operation in a wider range. . Further, if the bypass passage is formed by a plurality of holes, the flow path resistance of the bypass passage can be reduced, and the entire volume of the bypass passage can be reduced, so that the non-compressed volume generated by the bypass passage can be reduced, and Reduce the reduction in volumetric efficiency. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view of a screw compressor according to a first embodiment of the present invention. Fig. 2 is a view showing a volume V and a pressure P of an arbitrary compression chamber of the spiral rotor portion shown in Fig. 1. Relationship. 3 is a cross-sectional view taken along line AA of the screw compressor shown in FIG. 1; and FIG. 3(A) is a view showing a rotational position of a spiral rotor which is provided at the time of opening or just opening of the bypass passage of the discharge casing; Fig. 3(B) shows the spiral rotor rotation position when the bypass passage is fully open or just after full opening; the third (C) diagram shows that the compressed gas of the compression chamber starts from the male side discharge port provided to the discharge casing And the rotation position of the spiral rotor when the female side discharge port is discharged to the discharge chamber. Fig. 4 is a cross-sectional view showing a valve portion provided on the male side bypass passage of the screw compressor shown in Fig. 1. Fig. 5 is a cross-sectional view taken along line B-B of Fig. 4. The sixth modification of the embodiment shown in Fig. 6(A) and (B) is an enlarged view of the vicinity of the discharge port of Fig. 3. The other two -18-201013052 variants of the embodiment shown in Fig. 3(A)(B) are enlarged views of the vicinity of the discharge port of Fig. 3. In the eighth (A) and (B) drawings, still another two modified examples of the embodiment shown in Fig. 3 are enlarged views of the vicinity of the discharge port of Fig. 3. Fig. 9 is a view showing a flat spring valve and a valve pusher provided in a bypass passage provided in the vicinity of the discharge port portion shown in Fig. 8(B), and is a cross-sectional view taken along line F-F of Fig. 1; Fig. 10 is a cross-sectional view taken along line D-D of the valve portion shown in Fig. 9. φ The other embodiment of the example shown in Fig. 4 is equivalent to Fig. 4. Fig. 12 is a cross-sectional view of the vicinity of the valve portion as seen from the line C-C of Fig. 11. Fig. 13 is a cross-sectional view corresponding to the portion of Fig. 12, showing another example of the examples shown in Fig. 1 and Fig. 12. Fig. 14 is a cross-sectional view corresponding to the portion of Fig. 12, showing still another example of the examples shown in Fig. 11 and Fig. 12. 〇 Fig. 15 is a cross-sectional view of the vicinity of the valve portion as seen from the direction of the E-E line in Fig. 14. Fig. 16 is a cross-sectional view corresponding to the portion of Fig. 12 or Fig. 14 which is another example of the example shown in Fig. 11 and Fig. 12. [Description of main component symbols] 1 '·Main housing 2: Male rotor 2 A : Female rotor -19- 201013052 3 : Stator 4 : Rotor 6, 7 : Roller bearing 8 : Ball bearing 9 : Suction port 1 0 : Row Outlet 1 2 : discharge chamber 15 : end cover 瘳 1 6 : motor housing 17 : compressor unit 18 : motor portion 1 9 : discharge port 20 : suction port 2 1 : discharge housing 22 : motor 25 : oil groove @ 26 73: bolts 30a, 30b: compression chamber 40a: male side casing portion 40b: female side casing portion 42: male side discharge port 4 3: female side discharge port 44: radial discharge ports 50, 50a, 51 51a: bypass passage -20- 201013052 70 : valve 7 1 : valve push rod 80 : oil separator 100 : discharge passage 1 1 0, 1 3 5, 1 4 0 : valve (opening and closing valve) Π 1 : oil hole 1 12 : Spring φ 113 , 142 : Flange 1 1 4 : Screw 1 1 5 : Valve passage 1 1 6 : Valve part 1 1 7 : Spacer 120 : Male rotor rear face tangent 123 : Female rotor rear face tangent 1 3 1 : Stepping motor φ 1 3 2 : Control device 133 : Pressure sensor 134 : Shaft 1 3 6 : Solenoid valve 1 4 1 : Oil piping 143 : Cylinder