JP4852238B2 - Two stage screw compressor - Google Patents

Description

  The present invention relates to a two-stage screw compressor, and is particularly suitable for a two-stage screw compressor provided with a capacity control mechanism using a slide valve.

  As a conventional screw compressor which is an external oil supply system, for example, there is one described in Japanese Patent Laid-Open No. 8-151987 (Patent Document 1). In this screw compressor, a cylindrical bore and a recess are formed in a main casing, a male rotor and a female rotor are stored in the cylindrical bore, and a slide valve is stored in the recess. A motor casing is attached to one end of the main casing, and the motor is accommodated in the motor casing. A discharge casing having a discharge port and a discharge port is attached to the other end of the main casing. A side casing having a piston cylinder is further attached to one end of the discharge casing, and a hydraulic piston connected to a slide valve via a rod is accommodated in the cylinder. An oil passage communicating with an external pipe connected to the low pressure side is opened in the anti-slide valve side chamber of the piston cylinder. Further, in the piston sliding section on the inner surface of the piston cylinder, two oil passages communicating with an external pipe connected with an electromagnetic valve on the low pressure side are opened. These external pipes connected to the low-pressure side have a connection pipe structure joined together on the low-pressure side. Furthermore, in the slide valve side chamber of the piston cylinder, an oil passage communicating with an external pipe connected with electromagnetic valves on the high pressure side and the low pressure side is opened. This external piping has a connection piping structure branched to the high pressure side and the low pressure side.

JP-A-8-151987

  In the prior art, the branching and merging of the supply / discharge oil passage for driving the piston valve of the capacity control mechanism is formed by the external piping of the compressor, and therefore the branching and merging of the connecting piping accompanied by the welding work are diverse. It has become complicated, resulting in increased assembly complexity, increased assembly time, and increased costs. Further, in the prior art, since the main casing having the cylindrical bore and the concave portion and the side casing having the piston cylinder are configured separately, the assembly is complicated, the assembly time is increased, and the cost is increased. Was invited.

  An object of the present invention is to provide a two-stage screw compressor that can simplify the casing and the external piping to improve the assembling property, shorten the assembling time, and reduce the cost.

In order to achieve the foregoing object, the present invention accommodates a pair of male and female low-stage screw rotors whose axes are parallel and mesh with each other in a pair of low-stage cylindrical bores extending in the lateral direction and intersecting in the circumferential direction. A low-stage compressor, and a high-stage compressor that houses a pair of male and female high-stage screw rotors that are parallel to each other in a pair of high-stage cylindrical bores that extend in the lateral direction and intersect in the circumferential direction. With
The low-stage compressor includes a recess extending along the low-stage cylindrical bore, a piston chamber positioned laterally of the recess and extending in the lateral direction, and a plurality of low-stage oil passages for supplying and discharging oil to the piston chamber A low-stage main casing that is formed, a slide valve that is movably housed in the recess, a hydraulic piston that is housed in the piston chamber and drives the slide valve via a rod, and the plurality of low-stage oil passages. A high-stage oil passage that extends from the high-stage cylindrical bore, and a bypass that communicates with the high-stage cylindrical bore and extends to a suction side of the high-stage compressor. In the two-stage screw compressor including a high-stage main casing having a passage and a piston valve that is movably housed in the high-stage oil passage and opens and closes the bypass passage, the high-stage oil passage includes the plurality of low-stage oil passages. Corrugated oil Communicates with the high pressure oil passage to the oil supply the high pressure oil of the road, the piston valve by the high-pressure oil passage and the oil supplied to the high stage fluid passage through said solenoid valve provided in the middle of the high-pressure oil passage The low-stage main casing is operated to form the low-stage cylindrical bore, the concave portion, and the portion forming the piston chamber from the same member, and is located in front of the piston chamber and extends in the lateral direction. The plurality of low-stage oil passages have communication passages to the high-stage oil passages, and include the communication passages in the front-rear direction within the thick-wall portions. The lower oil passages in the plurality of low oil passages are divided in the middle and adjacent to the surface of the thick wall portion. If you have an opening provided A first low-stage oil passage portion connecting one opening in the adjacent opening and the piston chamber, and connecting the other opening and the other passage in the adjacent opening. A second low-stage oil passage portion, and each solenoid valve in the plurality of solenoid valves opens and closes between the adjacent openings in the low-stage oil passages on the surface of the thick wall portion. The plurality of solenoid valves are installed so as to communicate with each other as possible, and are arranged side by side in the lateral direction.

A more preferable specific configuration example in the present invention is as follows.
(1) the thick portion, the front surface constituting the surface has a long extending flat surface laterally along longer the piston chamber laterally, the opening definitive each low-stage oil communication path is the together provided adjacent to the upper and lower flat surfaces of the thick portion, wherein the plurality of adjacent openings provided arranged side by side in the lateral direction, each said first low-stage oil passage is the one opening from together extends rearwardly open to the piston chamber, the respective second low-stage oil passage is connected to the other passage extending且one laterally extending rearward from said other opening, said plurality of each solenoid valve in the solenoid valve, the flat surface of the thick portion, it is installed so as to communicate openably between opening provided in the adjacent definitive said each low-stage oil communication path.
(2) The thick portion includes a thick main body portion extending in the lateral direction and a thick protruding portion protruding upward from the center of the thick main body portion, and the thick main body portion and the thick wall portion. front of the protruding portion is formed by a flat surface coplanar, said plurality of low-stage oil passage, a plurality of first low-stage oil passage provided side by side in the opening to the lateral direction on the flat surface of the thick body portion When, and a second low-stage oil passage which is open to the flat surface of the thick projecting portion, said second low-stage oil passage, the horizontal direction in the plurality of first low-stage oil passage Between the openings of the two first low-stage oil passages arranged side by side to the piston chamber and located in the sliding section of the piston, the piston chamber is opened, and the plurality of solenoid valves the flat surface parts body portion and the thick projecting portion, put in the first low stage oil passage Michi及 beauty said second low-stage oil communication passage That is installed so as to communicate openably between said adjacent to an opening.

  According to the two-stage screw compressor of the present invention, the casing and the external piping can be simplified to improve the assembling property, shorten the assembling time, and reduce the cost.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.

  First, a screw compressor 50 according to a first embodiment of the present invention will be described with reference to FIGS.

  The overall configuration of the screw compressor 50 of the present embodiment will be described with reference to FIG. FIG. 1 is a sectional view of a screw compressor 50 according to a first embodiment of the present invention.

  The screw compressor 50 includes a low-stage compressor 51, a motor unit 52, a high-stage compressor 53, and a two-stage screw compressor having a supply / discharge oil path. The compressed gas flows from the low-stage compressor 51 to the high-stage compressor 53 via the motor unit 52 and is discharged outside the compressor. Therefore, in the following description, the low-stage side is the upstream side and the high-stage side is the downstream side. Show direction as side.

  The low-stage compressor 51 includes a low-stage main casing 1, a low-stage screw rotor 2, a slide valve 17, a rod 18, a piston 19, a coil spring 20, a discharge casing 22, roller bearings 8 and 9, and a ball bearing 10. Has been.

The low-stage main casing 1 includes a pair of cylindrical bores 1a extending in the lateral direction and intersecting in the circumferential direction, a recess 1b extending along the cylindrical bore 1a, a piston chamber 21 extending in the lateral direction, and a piston of the piston chamber 21 Oil passages 35 to 3 8 (see FIG. 2 and FIG. 4) for supplying and discharging oil are formed on both sides. Further, the portions forming the suction port 15, the suction chamber 61, the suction port 62, and the low-stage discharge port 63 are formed by the low-stage main casing 1 that is the same member. The suction port 15, the suction chamber 61, and the suction port 62 form a suction flow path to the low stage screw rotor 2. The low-stage discharge port 63 forms a discharge passage from the low-stage screw rotor 2.

  The low-stage screw rotor 2 includes a pair of low-stage male rotors 2A and a low-stage female rotor (not shown) meshed with each other, and is housed in a pair of cylindrical bores 1a. The shaft portions 64 and 65 provided on both sides of the low-stage male rotor 2A are supported by the roller bearing 8 installed in the low-stage main casing 1, the roller bearing 9 and the ball bearing 10 installed in the discharge casing 22. ing. Similarly to the low-stage male rotor 2 </ b> A, the low-stage female rotor is supported by roller bearings and ball bearings on shafts provided on both sides.

Slide valve 17 is intended to be bypassed to the suction side capacity control part of the suction refrigerant gas sucked into the engagement portion of the low-stage screw rotor 2, movable in the recess 1 b extending in the transverse direction It is stored in. The hydraulic piston 19 drives the slide valve 17 left and right through the rod 18 and is slidably accommodated in a piston chamber 21 extending in the lateral direction. The coil spring 20 is disposed on the anti-slide valve chamber side of the piston chamber 21 and applies a force that always presses the piston 19 toward the slide valve side. The slide valve 17, the rod 18, the piston 19, and the coil spring 20 constitute a capacity control mechanism.

  The motor unit 52 includes a motor casing 24, a motor stator 5, a motor rotor 6, a roller bearing 12, a motor cover 23, a ball bearing 11, and a gear coupling 7. The motor unit 52 is sandwiched between the low-stage compressor 51 and the high-stage compressor 53, and the driving force is transmitted to the low-stage male rotor 2A of the low-stage compressor 51 and the high-stage male rotor 3A of the high-stage compressor 53. Is configured to do.

  The motor stator 5 and the motor rotor 6 constitute a drive motor 85. The motor stator 5 is mounted on a motor casing 24, and the motor rotor 6 is fixed to a shaft portion 66 formed on one side of the high-stage male rotor 3A in the motor stator 5. The shaft portion 66 of the high-stage male rotor 3 </ b> A is supported on the motor casing 24 by the ball bearing 11 and the roller bearing 12 on both sides of the motor rotor 6. The tip end portion of the shaft portion 66 of the high-stage male rotor 3A is connected to the shaft portion 64 of the low-stage male rotor 2A via the gear coupling 7. With this configuration, the driving force of the driving motor 85 is transmitted to the low-stage male rotor 2A and the high-stage male rotor 3A. The low-stage and high-stage female rotors are driven by male rotors 2A and 3A.

  The high stage compressor 53 includes a high stage main casing 4, a high stage screw rotor 3, roller bearings 12, 13, ball bearings 14, a motor casing 24, a piston valve 26 (see FIG. 2), and a spring 41 (see FIG. 2). Etc. Here, the roller bearing 12 and the motor casing 24 are common to the components of the motor unit 52.

  The high-stage main casing 4 extends in the lateral direction and intersects in the circumferential direction with a pair of cylindrical bores 4a, a high-stage suction port 68, a high-stage discharge port 69, and the high-stage screw rotor 3 from the middle of compression. A bypass passage 25 (see FIG. 2) extending to the suction side and an oil passage 70 (see FIG. 2) are formed.

High-stage screw rotor 3 is constituted by a pair of high Dan'yu rotor 3A and high Danmesu rotor is meshed with each other (not shown) are housed in a pair of cylindrical bore 4a. Shaft portions 66 and 67 provided on both sides of the high Dan'yu rotor 3A is a roller bearing 12 installed on the motor casing 24, it is supported by a roller bearing 13 and ball bearings 14 installed high-stage main casing 4 Yes. Similarly to the high-stage male rotor 3A, the high-stage female rotor also has shaft portions provided on both sides supported by roller bearings and ball bearings.

  The piston valve 26 and the spring 41 are capacity control mechanism members of the high stage compressor 53 and are provided so as to open and close the bypass passage 25. One side of the piston valve 26 is installed so as to slide in the oil passage 70.

  Next, capacity control of the screw compressor 50 will be described with reference to FIGS. 2 is a supply and discharge system diagram of the capacity control mechanism of the screw compressor 50 of the present embodiment, FIG. 3 is a front view of the stage capacity control mechanism section of the low stage compressor 51 of the present embodiment, and FIG. FIG. 5 is a schematic view of the oil supply / discharge passage to the stage capacity control mechanism of the low stage compressor 51 in this embodiment.

The low-stage main casing 1 is positioned in front of the piston chamber 21 and forms a thick portion 1c. This front portion is a portion where the electromagnetic valves 27 to 30 can be easily installed without being obstructed by others. A plurality of oil passages 35 to 38 for supplying and discharging oil to the piston chamber 21 are formed in the thick portion 1c . These oil passages 35 to 38 are formed in the piston chamber 21 so as to open at a predetermined interval in the lateral direction.

A substantially vertical flat surface 1d is formed on the front surface of the thick portion 1c. The flat surface 1d is formed so that a middle portion of the oil passages 35 to 38 is divided and opened adjacent to the upper and lower sides. The oil passages 35 to 38 are formed to extend in the front-rear direction from the flat surface 1d into the thick portion 1c. Oil passage 35, 3 7, 38 these openings are a plurality of sets arranged laterally. Solenoid valve 27,2 9, 30 so as to open and close the oil passage 35,37,38 in which a plurality of sets arranged in the horizontal direction and is placed on a flat surface 1d. With the configuration according, oil passages 35, 3 7, 38 forming and electromagnetic valve 27,2 9, will be able to carry out 30 the installation of easily improving the assembling property by simplifying the external piping, the assembly time reduction and Cost reduction can be achieved.

The flat surface 1d is formed with a protruding flat surface 1e (see FIG. 3) protruding upward from the central portion in the horizontal direction. The projecting flat face 1e, are divided in the middle portion of the oil passage 3 6 adjacent vertically are formed so as to open. Is placed on the protruding flat surface 1e as solenoid valve 2 8 communicates openably This oil passage 3 6. With the configuration according refueling path of the oil passage 3 6 and the electromagnetic valve 2 8, the oil passage 35, 3 7, 38 and the solenoid valve 27,2 9, regardless of the 30 fueling pathway, it can be easily provided as an option .

  The plurality of oil supply passages 71, 72 to the plurality of oil passages 35, 38 extending in the front-rear direction are formed side by side so as to extend upward from the lower surface of the thick portion 1c. In front of these oil supply passages 71 and 72, a common oil supply passage 73 extending in the lateral direction from the side surface of the thick portion 1c is formed. An external pipe is connected to the opening side of the common oil supply passage 73. Oil supply passages 74, 75 extending rearward from the front surface of the thick portion 1 c are formed, and the oil supply passages 74, 75 are connected to the left and right portions of the common oil supply passage 73. The oil supply passages 71 and 72 and the oil supply passages 74 and 75 are connected by external pipes 76 and 77. With such a configuration, a simple oil supply structure can be achieved without using a branch structure for external piping for oil supply. In FIG. 5, the dotted line portion indicates the external piping portion.

  The oil discharge passages from the oil passages 35 to 37 extending in the front-rear direction are constituted by oil discharge passages 78, 79, 81 extending in the lateral direction and an oil discharge passage 80 extending in the vertical direction. The oil drain passages 78, 79, 81 extending in the horizontal direction extend in the horizontal direction at different positions in the vertical direction.

  The oil passage 38 of the oil passage 38 extending in the front-rear direction includes an oil discharge passage 82 extending in the lateral direction and an oil discharge passage 83 extending in the front-rear direction. The oil drainage passage 82 is bored from the left end surface of the low-stage main casing 1 and its opening is closed. The oil drainage passage 83 is bored from the front surface of the low-stage main casing 1, and an oil drainage external pipe 84 is connected to the opening.

  The oil passage, the oil supply passage, and the oil discharge passage described above are formed so as to extend linearly and three-dimensionally in the front-rear direction, the lateral direction, and the vertical direction inside the thick portion 1c. As a result, the external piping can be simplified to improve the assembling property, shorten the assembling time and reduce the cost.

  Next, the overall operation of the screw compressor 50 of the present embodiment will be described with reference to FIG.

  When the drive motor 85 of the motor unit 52 is energized and the motor rotor 6 is rotated, the low-stage screw rotor 2 and the high-stage screw rotor 3 are driven accordingly. As a result, the low-pressure refrigerant gas is sucked into the suction chamber 61 from the suction port 15, and then sucked into the pair of low-stage screw rotors 2 through the suction port 62, and is compressed by the low-stage screw rotor 2 to the intermediate pressure. It becomes refrigerant gas. The intermediate-pressure refrigerant gas is discharged from the low-stage discharge port 63 to the discharge casing 22, then sucked into the high-stage screw rotor 3 through the motor cover 23 and the motor casing 24, and further compressed by the high-stage screw rotor 3. Is done. The compressed high-pressure refrigerant gas is discharged from the discharge port 69 and discharged from the discharge port 16 to the outside.

  Although the compression reaction force acts on the screw rotors 2 and 3 by the compression operation, the radial load is supported by the roller bearings 8, 9, 12, and 13, and the thrust load is supported by the ball bearings 10, 11, and 14. Oil for lubrication and cooling of these bearings is supplied to each bearing portion from a separately installed oil tank. On the other hand, this oil is also used for operating the slide valve 17 and the piston valve 26 that perform capacity control of the low-stage compressor 51 and the high-stage compressor 53 for capacity control.

  Next, the operation of the capacity control mechanism of the present embodiment will be described with reference mainly to FIG.

  The capacity control is performed in the low-stage compressor 51 by sliding the slide valve 17 in the axial direction of the low-stage screw rotor 2 and adjusting the suction amount. That is, when the slide valve 17 slides in the discharge direction, excess refrigerant gas 43 in the intake refrigerant gas 42 sucked into the meshing portion of the low-stage screw rotor 2 is bypassed to the intake side, and only the necessary refrigerant gas is present. Is compressed by the low-stage screw rotor 2 and discharged as indicated by an arrow 44. The operation of the slide valve 17 is performed by applying hydraulic pressure to a piston 19 fixed to the slide valve 17 via a rod 18. On the other hand, in the high stage compressor 53, by applying hydraulic pressure to the piston valve 26, the bypass passage 26 is opened and closed to control the capacity.

  When performing the stage capacity control of the low stage compressor 51, the oil supply / discharge oil to the cylinder 21 is performed by the oil passages 35 to 38 via the solenoid valves 27 to 30 and the capillary tube 34. When the slide valve 17 is moved to the rightmost side, the operation is 100% load (load). Conversely, when the slide valve 17 is moved to the leftmost side, the operation is the minimum load. The compression capacity of the low stage compressor 51 is determined by which of the oil passages 35 to 37 is operated. Taking step control consisting of four steps of minimum load, 50% load, 75% load, and 100% load as an example, the operating states of the solenoid valves 27 to 30 in each load condition are as shown in Table 1.

すなわち、１００％ロード運転では、電磁弁２７、３０が開き、最も右側の油通路３５で開放された中間圧がピストン１９の右面に作用され、左面に高圧が作用することとなるため、スライド弁１７は右側一杯まで動いて１００％ロードに固定される。７５％ロード運転では、電磁弁２８、３０が開き、２番目に右側の油通路３６で開放された中間圧がピストン１９の右面に作用され、油通路３６の位置で圧力バランスして７５％ロードの位置で固定される。５０％ロード運転では、電磁弁２９、３０が開き、３番目に右側の油通路３７で開放された中間圧がピストン１９の右面に作用され、油通路３７位置で圧力バランスして５０％ロードの位置で固定される。

That is, in the 100% load operation, the solenoid valves 27 and 30 are opened, the intermediate pressure released by the rightmost oil passage 35 is applied to the right surface of the piston 19, and the high pressure is applied to the left surface. 17 moves to the full right and is fixed at 100% load. In the 75% load operation, the solenoid valves 28 and 30 are opened, and the intermediate pressure that is secondly opened in the right oil passage 36 is applied to the right surface of the piston 19 to balance the pressure at the position of the oil passage 36 and load 75%. It is fixed at the position. In the 50% load operation, the solenoid valves 29 and 30 are opened, and the intermediate pressure that is thirdly opened in the right oil passage 37 is applied to the right surface of the piston 19 to balance the pressure at the position of the oil passage 37 and achieve 50% load. Fixed in position.

  During these 50 to 100% load operations, high-pressure oil always acts on the piston valve 26 of the high-stage compressor 53, and the bypass path 25 leading from the mid-compression region to the pre-compression region (intermediate pressure side) is closed. .

  Further, in the minimum load operation necessary for reducing the starting torque at the time of starting the compressor, all the solenoid valves 27 to 30 are closed, high pressure oil is applied to the right surface of the piston 19, and the middle is opened in the oil passage 38. Since the pressure is applied to the left surface of the piston 19, the slide valve 17 moves to the left side and is fixed to the minimum load. At the same time, the pressure receiving surface of the piston valve 26 of the high-stage compressor 53 is also opened to the intermediate pressure, so that the bypass passage 25 that leads from the intermediate compression region to the pre-compression region (intermediate pressure side) is opened due to the force of the spring 41. It becomes a state.

  The coil spring 20 incorporated on the right side of the piston 19 is used to press the piston 19 all the way to the left when the compressor is stopped.

  Next, the screw compressor 50 of 2nd Example of this invention is demonstrated using FIG. FIG. 6 is a supply / discharge oil system diagram of the capacity control mechanism of the screw compressor 50 according to the second embodiment of the present invention. The second embodiment is different from the first embodiment as described below, and is basically the same as the first embodiment in other points.

  In the second embodiment, a continuous capacity control mechanism is provided. In the second embodiment in which continuous capacity control is performed, oil supply / discharge oil to the cylinder 21 is performed by the oil passages 39 and 40 via the solenoid valves 31, 32 and 33 and the capillary tube 34. The oil passages 39 and 40 are provided in the same manner as the oil passages 36 and 38 of the first embodiment.

  Table 2 shows the operating states of the solenoid valves 31 to 33 during the continuous control.

すなわち、中間保持位置からロードアップする場合、電磁弁３２のみを開とした状態から、電磁弁３１〜３３を全て開とし、ピストン１９の右側のシリンダ２１から油を中間圧側へ排出する。また、中間保持位置からロードダウンする場合、電磁弁３２のみを開とした状態から、電磁弁３３のみ開とし、ピストン１９の左側のシリンダ２１から油を中間圧側へ排出する。

That is, when loading from the intermediate holding position, from the state where only the solenoid valve 32 is opened, all the solenoid valves 31 to 33 are opened, and the oil is discharged from the cylinder 21 on the right side of the piston 19 to the intermediate pressure side. When the load is lowered from the intermediate holding position, only the solenoid valve 32 is opened from the state where only the solenoid valve 32 is opened, and the oil is discharged from the cylinder 21 on the left side of the piston 19 to the intermediate pressure side.

  Further, at the time of starting and stopping, only the electromagnetic valve 33 is opened so that the slide valve 17 of the low-stage compressor 51 reaches the left side as well as in the case of the stage control, and the high-stage compressor. The piston valve 26 of 53 is moved by the spring 41 so that the bypass path 25 leading from the mid-compression region to the pre-compression region (intermediate pressure side) is opened. With the above operation, capacity control can be easily performed for both the low-stage compressor 51 and the high-stage compressor 53.

It is sectional drawing of the screw compressor of 1st Example of this invention. It is a supply-and-discharge oil system figure of the capacity control mechanism of the screw compressor of the 1st example. It is a front view of the stage capacity | capacitance control mechanism part of the low stage compressor in 1st Example. It is AA sectional drawing of FIG. It is the schematic of the oil supply / discharge oil passage to the stage capacity control mechanism part of the low stage compressor in the 1st example. It is a supply-and-discharge oil system figure of the capacity control mechanism of screw compressor 50 of the 2nd example of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Low stage main casing, 1a ... Cylindrical bore, 1b ... Concave part, 1c ... Thick part, 1d ... Flat surface, 2 ... Low stage screw rotor, 2A ... Low stage male rotor, 3 ... High stage screw rotor, 3A ... high stage male rotor, 4 ... high stage main casing, 4a ... cylindrical bore, 5 ... motor stator, 6 ... motor rotor, 7 ... gear coupling, 8, 9 ... roller bearings, 10, 11 ... ball bearings, 12, 13 ... Roller bearing, 14 ... Ball bearing, 15 ... Suction port, 16 ... Discharge port, 17 ... Slide valve, 18 ... Rod, 19 ... Piston, 20 ... Coil spring, 21 ... Piston chamber, 22 ... Discharge casing, 23 ... Motor cover , 24 ... motor casing, 25 ... bypass passage, 26 ... piston valve, 27-33 ... solenoid valve, 34 ... capillary tube, 35-40 ... oil passage, 41 ... spring, 50 ... scoop Compressor 51 ... Low stage compressor 52 ... Motor part 53 ... High stage compressor 61 ... Suction chamber 62 ... Low stage suction port 63 ... Low stage discharge port 64-67 ... Shaft part 68 ... High-stage intake port, 69 ... High-stage discharge port, 70 ... Oil passage, 71, 72 ... Oil supply passage, 73 ... Common oil supply passage, 74,75 ... Oil supply passage, 76, 77 ... External piping, 78-83 ... Exhaust Oil passage, 84 ... exhaust oil external piping, 85 ... electric motor.

Claims (3)

A low-stage compressor that houses a pair of male and female low-stage screw rotors that are parallel to each other in a pair of low-stage cylindrical bores that extend in the lateral direction and intersect in the circumferential direction, and a circumferential direction that extends in the lateral direction A pair of high-stage compressors that house a pair of male and female high-stage screw rotors whose axes are parallel and mesh with each other in a pair of high-stage cylindrical bores that intersect with each other,
The low-stage compressor includes a recess extending along the low-stage cylindrical bore, a piston chamber positioned laterally of the recess and extending in the lateral direction, and a plurality of low-stage oil passages for supplying and discharging oil to the piston chamber A low-stage main casing that is formed, a slide valve that is movably housed in the recess, a hydraulic piston that is housed in the piston chamber and drives the slide valve via a rod, and the plurality of low-stage oil passages. With a plurality of solenoid valves to open and close,
The high-stage compressor includes a high-stage oil passage extending from the high-stage cylindrical bore, a high-stage main casing that forms a bypass passage that communicates with the high-stage cylindrical bore and extends to a suction side of the high-stage compressor; In a two-stage screw compressor comprising a piston valve movably housed in the high stage oil passage and opening and closing the bypass passage,
The high-stage oil passage is communicated with a high-pressure oil passage for supplying high-pressure oil among the plurality of low-stage oil passages,
The piston valve is operated by oil supplied to the high-stage oil passage through the high- pressure oil passage and the electromagnetic valve provided in the middle of the high-pressure oil passage ,
The low-stage main casing is formed of the same member with the low-stage cylindrical bore, the recess and the piston chamber, and is located in front of the piston chamber and extends in the lateral direction and is exposed to the outside. Has a thick part,
The plurality of low-stage oil passages have a communication passage to the high-stage oil passage, and are linear in the front-rear direction, the lateral direction, and the up-down direction inside the thick portion including the communication passage. And formed to extend three-dimensionally,
Each of the low-stage oil passages in the plurality of low-stage oil passages has an opening provided adjacent to the surface of the thick-walled part by dividing the middle portion, and one of the openings provided adjacent to each other. A first low-stage oil passage portion that connects the opening and the piston chamber, and a second low-stage oil passage portion that connects the other opening and the other passage in the adjacent opening,
Each solenoid valve in the plurality of solenoid valves is installed on the surface of the thick portion so as to communicate between the adjacent openings in the low-stage oil passages so as to be openable and closable. The two-stage screw compressor is characterized in that the solenoid valves are installed side by side in the horizontal direction. The two-stage screw compressor according to claim 1,
The thick portion has a flat surface extending in the lateral direction along the piston chamber in the lateral direction on the front surface constituting the surface,
The openings in the respective low-stage oil passages are provided vertically adjacent to the flat surface of the thick wall portion, and the plurality of adjacently provided openings are provided side by side in the lateral direction,
Each of the first low-stage oil passage portions extends rearward from the one opening and opens into the piston chamber, and each of the second low-stage oil passage portions extends rearward from the other opening and laterally Connected to the other passage extending to
Each solenoid valve in the plurality of solenoid valves is installed on the flat surface of the thick portion so as to communicate between the adjacent openings in each low-stage oil passage so as to be openable and closable. Features a two-stage screw compressor. The two-stage screw compressor according to claim 2,
The thick portion has a thick main body portion extending long in the lateral direction, and a thick protruding portion protruding upward from the center of the thick main body portion,
The front surface of the thick-walled main body portion and the thick-walled protruding portion is formed of a flat surface that is coplanar,
The plurality of low-stage oil passages are opened on the flat surface of the thick-walled main body portion and opened on the flat surface of the plurality of first low-stage oil passages arranged side by side and the thick-wall protruding portion. A second low stage oil passage,
The second low-stage oil passage is between openings of the two first low-stage oil passages arranged in the lateral direction in the plurality of first low-stage oil passages to the piston chamber, and slides of the piston. Located in the moving section, opened to the piston chamber,
The plurality of solenoid valves open and close between the adjacent openings in the first low-stage oil passage and the second low-stage oil passage on the flat surfaces of the thick-wall body portion and the thick-projection portion. A two-stage screw compressor, characterized in that it is installed to communicate with each other.

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