EP4361444A1 - Screw compressor - Google Patents

Screw compressor Download PDF

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Publication number
EP4361444A1
EP4361444A1 EP21946952.5A EP21946952A EP4361444A1 EP 4361444 A1 EP4361444 A1 EP 4361444A1 EP 21946952 A EP21946952 A EP 21946952A EP 4361444 A1 EP4361444 A1 EP 4361444A1
Authority
EP
European Patent Office
Prior art keywords
rotating shaft
cylindrical portion
casing
inner cylindrical
end portion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21946952.5A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP4361444A4 (en
Inventor
Naoya Mitsunari
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Publication of EP4361444A1 publication Critical patent/EP4361444A1/en
Publication of EP4361444A4 publication Critical patent/EP4361444A4/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/48—Rotary-piston pumps with non-parallel axes of movement of co-operating members
    • F04C18/50—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees
    • F04C18/52—Rotary-piston pumps with non-parallel axes of movement of co-operating members the axes being arranged at an angle of 90 degrees of intermeshing engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/10—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
    • F04C28/12—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/30—Casings or housings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2250/00—Geometry
    • F04C2250/10—Geometry of the inlet or outlet
    • F04C2250/102—Geometry of the inlet or outlet of the outlet

Definitions

  • the present disclosure relates to a screw compressor used for, for example, refrigerant compression of a refrigerator.
  • Some screw compressor includes one screw rotor and two gate rotors.
  • the screw rotor and the gate rotors of such a screw compressor are accommodated in a casing.
  • the screw rotor has a helical groove referred to as a screw groove.
  • Such screw grooves mesh with and are engaged with the paired gate rotors disposed in radial directions of the screw rotor, thereby forming compression chambers.
  • a slide valve is disposed beside the outer circumference of the screw rotor such that the slide valve is movable in the rotational axis direction of the screw rotor, and the internal volume ratio can be adjusted by adjusting the discharge timing of the fluid compressed in each of the compression chambers.
  • the slide valve can also serve as a capacity control mechanism that can adjust the compression capacity.
  • the casing of the screw compressor has a cylindrical wall for housing the screw rotor and a semicylindrical wall for housing the slide valve.
  • the casing with the cylindrical wall, the semicylindrical wall, and a pair of compression chambers, forms a flow passage of the compressed refrigerant gas.
  • High pressure is applied to an inner wall of the casing of the screw compressor during the operation of the compressor or a pressure resistance test conducted in which the inside of the screw compressor is pressurized.
  • stress is concentrated locally on the semicylindrical wall housing the slide valve because of the applied pressure and plastically deforms the material, and permanent strain may thereby remain in the casing after the load is removed.
  • a gap cannot be kept constant in size between the cylindrical wall that has been deformed into, for example, an oval shape and the outer circumferential surface of the screw rotor, and leakage of the refrigerant gas from the compression chamber during the operation of the compressor thereby increases.
  • the performance of the compressor may be decreased.
  • Patent Literature 1 Japanese Unexamined Patent Application Publication No. 2009-243412
  • the present disclosure has been made to solve such above-described problems, and an object of the present disclosure is to provide a screw compressor with which plastic deformation caused by a pressure resistance test or elastic deformation caused during the operation of the compressor can be prevented or reduced, and permanent strain that remains in a casing after a load is removed can be reduced.
  • a screw compressor includes a casing forming a contour, a screw rotor accommodated inside the casing such that the screw rotor is movable and having an outer circumferential wall having a helical groove, a gate rotor accommodated inside the casing and having a tooth that meshes with the helical groove of the screw rotor, and a slide valve accommodated inside the casing and disposed such that the slide valve is slidable in an axial direction of a rotating shaft of the screw rotor.
  • the casing includes an inner cylindrical portion having a hollow cylindrical shape and housing the screw rotor, an intermediate inner cylindrical portion having a hollow cylindrical shape such that an inner circumferential wall of the intermediate inner cylindrical portion faces an outer circumferential wall of the inner cylindrical portion at an end portion of the casing on one side in the axial direction of the rotating shaft, an outer cylindrical portion having a hollow cylindrical shape such that an inner circumferential wall of the outer cylindrical portion faces an outer circumferential wall of the intermediate inner cylindrical portion at the end portion of the casing on the one side in the axial direction of the rotating shaft and formed in the axial direction of the rotating shaft, a semicylindrical portion serving as a wall portion forming a semicylindrical groove inside the intermediate inner cylindrical portion, the semicylindrical portion being formed integrally with the inner cylindrical portion and the intermediate inner cylindrical portion and housing the slide valve inside the semicylindrical portion, and a protruding portion serving as a wall extending in a radial direction of the rotating shaft and in the axial direction of the
  • Fig. 1 is a front view of a screw compressor 1 according to Embodiment 1.
  • Fig. 2 illustrates schematically a configuration of the screw compressor 1 according to Embodiment 1 and is a sectional view at the position of line A-A of Fig. 1 .
  • Fig. 3 illustrates schematically another configuration of the screw compressor 1 according to Embodiment 1 and is a sectional view at the position of line A-A of Fig. 1 .
  • Fig. 4 is a front view of the structure of an end portion 2a, on one side in the longitudinal direction, of the screw compressor 1 according to Embodiment 1.
  • Fig. 5 is a schematic side view illustrating schematically a side face of the screw compressor 1 according to Embodiment 1. Note that, in Fig.
  • a slide-valve driving mechanism 11 illustrated in Fig. 2 is removed for the purpose of illustration of a wall of a casing 2.
  • Fig. 2 different from Fig. 3 is a structure of protruding portions 25.
  • the configurations of the screw compressors 1 will be described with reference to Figs. 1 to 5 .
  • the screw compressor 1 includes the casing 2 forming the contour, a screw rotor 3, gate rotors 6, and slide valves 10.
  • the screw compressor 1 further includes a motor 4, which drives and rotates the screw rotor 3.
  • the casing 2 houses the screw rotor 3, the gate rotors 6, and the slide valves 10 inside the casing 2.
  • the casing 2 further houses the motor 4 inside the casing 2.
  • the casing 2 includes an inner cylindrical portion 21, an intermediate inner cylindrical portion 22, an outer cylindrical portion 23, semicylindrical portions 24, and the protruding portions 25.
  • the inner cylindrical portion 21 has a hollow cylindrical shape and houses the screw rotor 3 inside the inner cylindrical portion 21.
  • An inner circumferential wall 21a of the inner cylindrical portion 21 faces the screw rotor 3 or a rotating shaft 5, which will be described later.
  • the inner cylindrical portion 21 is formed such that the inner cylindrical portion 21 extends in an axial direction AD of the rotating shaft 5.
  • the inner cylindrical portion 21 has inside through holes 21c, which are through holes, and, through the inside through holes 21c, the space defined by the inner cylindrical portion 21 and the spaces defined by the semicylindrical portions 24 communicate with one another.
  • the inner cylindrical portion 21 further has a through hole (not illustrated) communicating with spaces in which the gate rotors 6 is disposed.
  • the intermediate inner cylindrical portion 22 has a hollow cylindrical shape such that an inner circumferential wall 22a of the intermediate inner cylindrical portion 22 faces an outer circumferential wall 21b of the inner cylindrical portion 21.
  • the intermediate inner cylindrical portion 22 is formed such that the intermediate inner cylindrical portion 22 extends in the axial direction AD of the rotating shaft 5.
  • a part of an outer circumferential wall 22b of the intermediate inner cylindrical portion 22 is exposed outside the casing 2 and forms a part of the contour of the casing 2, between the outer cylindrical portion 23 and a motor accommodation portion 27, which will be described later.
  • the casing 2 may have a structure in which the outer circumferential wall 22b of the intermediate inner cylindrical portion 22 and the contour of the casing 2 are separated structures, and there may be a difference in diameter between the outer circumferential wall 22b of the intermediate inner cylindrical portion 22 and the contour of the casing 2.
  • the inner cylindrical portion 21 and the intermediate inner cylindrical portion 22 form a cylindrical portion 20.
  • the cylindrical portion 20 has a hollow cylindrical shape such that the cylindrical portion 20 extends in the axial direction AD of the rotating shaft 5.
  • the outer cylindrical portion 23 has a hollow cylindrical shape such that an inner circumferential wall 23a of the outer cylindrical portion 23 faces the outer circumferential wall 22b of the intermediate inner cylindrical portion 22.
  • the outer cylindrical portion 23 is formed such that the outer cylindrical portion 23 extends in the axial direction AD of the rotating shaft 5.
  • the outer cylindrical portion 23 has a length smaller than the length of the intermediate inner cylindrical portion 22 in the axial direction AD of the rotating shaft 5. Note that the above-described structure is one form of the casing 2, and the outer cylindrical portion 23 may have, in the axial direction AD of the rotating shaft 5, a length equal to or a length larger than the length of the intermediate inner cylindrical portion 22.
  • the outer cylindrical portion 23 includes a bottom wall portion 23c closer to an end portion 2b on the other side than the end portion 2a on one side in the axial direction AD of the rotating shaft 5, and the bottom wall portion 23c is connected to the outer circumferential wall 22b of the intermediate inner cylindrical portion 22.
  • the semicylindrical portions 24 each have a semicylindrical shape such that the semicylindrical portion 24 bulges outward from the inner cylindrical portion 21 in a radial direction RD of the rotating shaft 5, and an apex portion 24a of the semicylindrical portion 24 is formed integrally with the intermediate inner cylindrical portion 22.
  • the semicylindrical portions 24 are formed in the cylindrical portion 20 formed by the inner cylindrical portion 21 and the intermediate inner cylindrical portion 22.
  • the semicylindrical portions 24 are each a wall portion forming a semicylindrical groove inside the intermediate inner cylindrical portion 22.
  • the semicylindrical portions 24 are each formed integrally with the inner cylindrical portion 21 and the intermediate inner cylindrical portion 22 and each house the slide valve 10 inside the semicylindrical portion 24.
  • the semicylindrical grooves each serve as a slide-valve accommodation groove 24b.
  • the slide valves 10 are accommodated in the slide-valve accommodation grooves 24b such that the slide valves 10 are slidable along the slide-valve accommodation grooves 24b.
  • the semicylindrical portions 24 and the slide-valve accommodation grooves 24b are each formed such that the semicylindrical portion 24 and the slide-valve accommodation groove 24b extend in the axial direction AD of the rotating shaft 5.
  • Sets of the semicylindrical portions 24 and the respective slide-valve accommodation grooves 24b are point symmetric about the rotating shaft 5 and formed at positions on both respective sides of the screw rotor 3.
  • the protruding portions 25 are each a wall extending in a radial direction RD of the rotating shaft 5 and in the axial direction AD of the rotating shaft 5 and protrude from the outer circumferential wall 22b of the intermediate inner cylindrical portion 22 at respective positions where the semicylindrical portions 24 and the intermediate inner cylindrical portion 22 are integrated to each other. That is, the protruding portions 25 are each formed on the corresponding one of the bulging apex portions 24a of the semicylindrical portions 24 and extend outward from the semicylindrical portions 24 in radial directions RD of the rotating shaft 5. Note that, because the semicylindrical portions 24 are formed in the cylindrical portion 20, the protruding portions 25 are formed, in the cylindrical portion 20, on parts of the semicylindrical portions 24.
  • the protruding portions 25 are each a part of the casing 2 and each have the same length as the semicylindrical portions 24 in the axial direction AD of the rotating shaft 5 as Fig. 2 illustrates.
  • the length of the protruding portions 25 to the inner circumferential wall 23a of the outer cylindrical portion 23 is the maximum possible length of the protruding portions 25.
  • a width W1 (refer to Fig. 1 ) of the protruding portions 25 in a circumferential direction CD of the rotating shaft 5 is smaller than a length L1 (refer to Fig. 2 ) of the protruding portions 25 in the axial direction AD of the rotating shaft 5.
  • the protruding portions 25 may each have a columnar shape or a rib shape. As Fig. 2 illustrates, such columnar-shaped protruding portions 25 are each formed such that, in a radial direction RD of the rotating shaft 5, an end portion of the protruding portion 25 on one side is formed integrally with the intermediate inner cylindrical portion 22, and an end portion of the protruding portion 25 on the other side is formed integrally with the outer cylindrical portion 23.
  • the columnar-shaped protruding portions 25 are each formed such that the protruding portion 25 connects the intermediate inner cylindrical portion 22 and the outer cylindrical portion 23 to one another.
  • such rib-shaped protruding portions 25 are each formed such that, in a radial direction RD of the rotating shaft 5, an end portion of the protruding portion 25 on one side is formed integrally with the intermediate inner cylindrical portion 22, and at least a part of an end portion of the protruding portion 25 on the other side faces the inner circumferential wall 23a of the outer cylindrical portion 23.
  • the inside of the casing 2 is divided by a partition (not illustrated) into a low-pressure side, which is the suction side of refrigerant, and a high-pressure side, which is the discharge side of refrigerant.
  • a space on the low-pressure side serves as a low-pressure chamber 15 having a suction-pressure atmosphere.
  • a space on the high-pressure side serves as a high-pressure chamber 16 having a discharge-pressure atmosphere.
  • a discharge flow passage 7 and an inlet portion 7a, which is opened to the discharge flow passage 7, are formed.
  • the discharge flow passage 7 is formed by walls forming the casing 2 and forms a part of the high-pressure chamber 16.
  • the inlet portion 7a serving as an entrance part of the discharge flow passage 7 for the compressed refrigerant is formed in the semicylindrical portions 24 and is formed such that the inlet portion 7a faces the slide valves 10.
  • An outlet portion 7b serving as an exit part of the discharge flow passage 7 for the compressed refrigerant is formed between the intermediate inner cylindrical portion 22 and the outer cylindrical portion 23 in a radial direction RD of the rotating shaft 5. That is, the opening face of the inlet portion 7a faces in a radial direction RD of the rotating shaft 5, and the opening face of the outlet portion 7b faces in the axial direction AD of the rotating shaft 5.
  • Fig. 6 illustrates schematically the section of the screw compressor 1 according to Embodiment 1 at the position of line B-B in Fig. 2 .
  • the internal structure of the casing 2 will further be described with reference to Figs. 2 and 6 .
  • the screw rotor 3 is accommodated inside the casing 2 such that the screw rotor 3 is movable.
  • the screw rotor 3 has a columnar shape and has an outer circumferential wall having plural screw grooves 3a, which are helical grooves.
  • the screw grooves 3a mesh with and are engaged with a pair of gate rotors 6 disposed in a radial direction RD from the screw rotor 3 and form compression chambers 14.
  • one end is the suction side of fluid, and the other end is the discharge side.
  • the screw rotor 3 is disposed around and fixed to the rotating shaft 5 (refer to Fig. 2 ).
  • a motor rotor 4b of the motor 4 is also fixed to the rotating shaft 5.
  • the screw rotor 3 is rotated with the rotation of the rotating shaft 5 caused by the rotation of the motor rotor 4b fixed to the rotating shaft 5.
  • the screw rotor 3 is driven to rotate by the motor 4, the fluid in the low-pressure space is sucked into the compression chambers 14 and compressed, and the fluid that has been compressed in the compression chambers 14 passes through a discharge port 8, which will be described later, and is discharged into the high-pressure space.
  • An end portion of the rotating shaft 5 on the discharge side (on the AD1 side in Fig. 2 ) is supported by a bearing housing 13 such that the end portion of the rotating shaft 5 is movable.
  • the bearing housing 13 supports the rotating shaft 5 with a main bearing 12 interposed between the bearing housing 13 and the rotating shaft 5.
  • the bearing housing 13 is provided in the inner cylindrical portion 21 at the end portion of the rotating shaft 5 on the discharge side (on the AD1 side in Fig. 2 ).
  • an end portion of the rotating shaft 5 on the suction side (on the AD2 side in Fig. 2 ) is supported by a sub-bearing (not illustrated) such that the end portion of the rotating shaft 5 is movable.
  • the screw compressor 1 includes two gate rotors 6.
  • the two gate rotors 6 are point symmetric about the rotating shaft 5 and disposed at positions on both respective sides of the screw rotor 3.
  • Each of the gate rotors 6 is accommodated inside the casing 2 and includes gate-rotor teeth 6a, which mesh with the screw grooves 3a, which are helical grooves of the screw rotor 3.
  • the gate rotors 6 each have a disk shape and each include the plural gate-rotor teeth 6a provided in the outer circumferential surface of the gate rotor 6 and arranged in the circumferential direction.
  • the gate-rotor teeth 6a of the gate rotors 6 mesh with the screw grooves 3a. Spaces surrounded by the gate-rotor teeth 6a of the gate rotors 6, the screw grooves 3a, and the inner circumferential wall 21a of the inner cylindrical portion 21 of the casing 2 form the compression chambers 14 in which refrigerant is compressed.
  • the compression chambers 14 are formed by the screw rotor 3, the gate rotors 6, the casing 2, and the slide valves 10, and a narrow gap is left between each of the components.
  • the compressed gas leaks from such gaps during compression, and widening gaps thereby cause reduction in the performance of the compressor.
  • the slide valves 10 are moved by a load being exerted outward in radial directions due to a difference in pressure between the inside of the compression chambers 14 and the low-pressure chamber 15, which is the low-pressure space.
  • widening of the gap between the screw rotor 3 and the slide valves 10 causes reduction in the performance of the compressor.
  • the plural compression chambers 14 are formed at positions where the plural compression chambers 14 are point symmetric about the center, in radial directions RD, of the screw rotor 3.
  • the screw compressor 1 may be of a type including one gate rotor 6, which meshes with one screw rotor 3 and thus forms a compression chamber 14.
  • the gate rotors 6 are each supported by the corresponding one of gate-rotor supports 6b of metal at the side of the gate rotor 6 opposite to the other side that faces the compression chambers 14 to resist the pressure of the compression chambers 14.
  • Each of the slide valves 10 is accommodated inside the casing 2 and disposed such that a narrow gap is ensured between the slide valve 10 and the outer circumference of the screw rotor 3.
  • the slide valves 10 are each disposed such that the slide valve 10 is slidable in the axial direction AD of the rotating shaft 5 of the screw rotor 3.
  • the slide valves 10 each slide along the outer circumferential surface of the screw rotor 3 in the axial direction AD.
  • the slide valves 10 and the casing 2 are integrated to each other and together form the compression chambers 14.
  • the slide valves 10 form the discharge port 8, and the timing of opening of the discharge port 8, that is, the timing at which the compression chambers 14 communicate with the discharge flow passage 7 changes depending on the positions of the slide valves 10.
  • the internal volume ratio of the screw rotor 3 is adjusted by changing the timing of opening of the discharge port 8 as described above.
  • the internal volume ratio refers to a value obtained by dividing the volume of the compression chambers 14 when suction is completed by the volume of the compression chambers 14 when discharge is started.
  • the slide valves 10 each have a columnar shape and each include a valve body portion 10c, a guide portion 10a, and a coupling portion 10b.
  • the valve body portions 10c each face the screw rotor 3 and form the compression chambers 14 together with the screw rotor 3.
  • the valve body portions 10c have the discharge port 8, which is a through hole passing through in a radial direction RD of the rotating shaft 5.
  • the discharge port 8 allows the discharge flow passage 7 and the compression chambers 14 to communicate with one another at a position where the pressure of the compression chambers 14 is high, and the discharge port 8 forms a flow passage through which refrigerant is moved from the compression chambers 14 to the discharge flow passage 7.
  • the guide portions 10a each have a columnar shape and each guide the movement of the corresponding one of the valve body portions 10c.
  • the guide portions 10a each have a guide surface facing the bearing housing 13.
  • the coupling portions 10b each couple one of the valve body portions 10c and the corresponding one of the guide portions 10a to one another.
  • the slide-valve driving mechanism 11 which causes the slide valves 10 to slide in the rotational axis direction of the screw rotor 3, is disposed at an end portion of the screw rotor 3 on the opposite side from the motor 4.
  • the slide valves 10 are connected to the slide-valve driving mechanism 11 by use of a coupling rod 10d.
  • the slide-valve driving mechanism 11 allows the slide valves 10 to slide in the axial direction AD of the rotating shaft 5 of the screw rotor 3.
  • the slide-valve driving mechanism 11 can also serve as a capacity control mechanism that can adjust the compression capacity by shifting the timing of closure completion of the compression chambers 14, and the compression capacity can be adjusted by the slide valves 10 sliding in the axial direction AD.
  • Examples of a power source for the slide-valve driving mechanism 11, which drives the slide valves 10, include, but not limited to, power sources using gas pressure, oil pressure, and, for example, a motor other than a piston.
  • the motor 4 includes a stator 4a inscribed in and fixed to the casing 2 and the motor rotor 4b disposed inside the stator 4a.
  • a controller (not illustrated) controls the rotation frequency of the motor 4.
  • the screw compressor 1 enables the adjustment of the compression capacity by controlling the rotation frequency of the motor 4.
  • the screw rotor 3 and the motor rotor 4b are both disposed on the same axis and both fixed to the rotating shaft 5.
  • the screw rotor 3 of the screw compressor 1 is rotated by being driven by the motor 4.
  • Fig. 7 illustrates the compression principle of the operation of the screw compressor 1 according to Embodiment 1.
  • a suction stroke is illustrated in (a)
  • a compression stroke is illustrated in (b)
  • a discharge stroke is illustrated in (c).
  • an operation of the screw compressor 1 according to Embodiment 1 will be described with reference to Fig. 7 .
  • Fig. 7 illustrates, the screw rotor 3 is rotated by the motor 4 (refer to Fig. 2 ) through the rotating shaft 5 (refer to Fig. 2 ), and the gate-rotor teeth 6a thereby move relatively to each other inside the compression chambers 14.
  • the suction stroke, the compression stroke, and the discharge stroke are counted as one cycle, and the cycle is repeated.
  • each of the strokes will be described while one of the compression chambers 14 illustrated by dots in Fig. 7 is focused.
  • the state of the focused one of the compression chambers 14 in the suction stroke is illustrated in (a).
  • the screw rotor 3 is driven by the motor 4, thereby rotating in a direction of the solid-line arrow.
  • the volume of the focused compression chamber 14 is reduced.
  • the focused compression chamber 14 comes to communicate with the discharge port 8 formed in the valve body portions 10c of the slide valves 10.
  • the high-pressure refrigerant gas that has been compressed in the focused compression chamber 14 passes through the inside through holes 21c, the discharge port 8, and the inlet portion 7a (refer to Fig. 2 ), flows into the discharge flow passage 7, passes through the discharge flow passage 7, and is discharged outside the compressor.
  • similar compression is performed again at the back of the screw rotor 3. Due to the above-described operation, the inside of the casing 2 is divided into the low-pressure chamber 15, which is a low-pressure space, and the high-pressure chamber 16, which is a high-pressure space.
  • the screw compressor 1 according to Embodiment 1 has the inside through holes 21c provided in respective parts, of the inner cylindrical portion 21 housing the screw rotor 3, at which the slide valves 10 are disposed, and the respective parts thus have no walls of the inner cylindrical portion 21.
  • the inner cylindrical portion 21 is connected to the semicylindrical portions 24 housing the slide valves 10.
  • Fig. 8 is a conceptual view applied with the analytical results of a part, of a casing 2 of a screw compressor 1L according to a comparative example, on which stress concentrates.
  • Fig. 9 is a conceptual view of a form of deformation of the casing 2 of the screw compressor 1L according to the comparative example when a pressure exceeding the design pressure is applied.
  • the screw compressor 1L according to the comparative example is a compressor having no protruding portions 25 and has the same structure as the screw compressor according to Embodiment 1 except for such absence of the protruding portions 25.
  • a single screw compressor is typically subjected to a pressure resistance test determined by the laws and regulations regarding high-pressure gas. Such a pressure resistance test is conducted on a contour component of the single screw compressor, and the inside of the casing is applied with a pressure exceeding a design pressure.
  • the shapes of the intermediate inner cylindrical portion 22 and the inner cylindrical portion 21, which are integrated with the semicylindrical portions 24, are also changed through the above-described mechanism, and the roundness of each of the intermediate inner cylindrical portion 22 and the inner cylindrical portion 21 may thereby increase.
  • the casing 2 is strained when the roundness of each of the intermediate inner cylindrical portion 22 and the inner cylindrical portion 21 increases. For example, as Fig.
  • each of the inner cylindrical portion 21 and the intermediate inner cylindrical portion 22 of the screw compressor 1L according to the comparative example is deformed into an oval shape whose minor radius is an axis connecting the center of the cylindrical portion 20 and each of the centers of the semicylindrical portions 24 to one another.
  • the casing 2 of the screw compressor 1 includes the protruding portions 25, which are each a wall extending in a radial direction RD of the rotating shaft 5 and in the axial direction AD of the rotating shaft 5 and protrude from the outer circumferential wall 22b of the intermediate inner cylindrical portion 22 at respective positions where the semicylindrical portions 24 and the intermediate inner cylindrical portion 22 are integrated to each other.
  • the positions where the semicylindrical portions 24 and the intermediate inner cylindrical portion 22 are integrated to each other are equivalent to respective positions of the parts P of the casing 2 to which local stress is applied. That is, the positions where the protruding portions 25 are formed is the respective positions of the parts P in the casing 2 to which local stress is applied.
  • the screw compressor 1 when internal pressure is applied to the casing 2, the roundness of each of the inner cylindrical portion 21, which is formed integrally with the semicylindrical portions 24, and the intermediate inner cylindrical portion 22 is prevented from increasing by the protruding portions 25.
  • the gap between the intermediate inner cylindrical portion 22 or the cylindrical portion 20 and the outer cylindrical portion 23 is prevented from widening in the screw compressor 1, reduction of leak of the refrigerant gas that leaks from the compression chambers 14 during the operation of the compressor is enabled, and there can be provided such a high-performance screw compressor. That is, the gap between the cylindrical portion 20 and the outer circumferential surface of the screw rotor 3 can be kept constant in the screw compressor 1, and such a high-performance screw compressor can thus be provided.
  • the screw compressor 1 having the protruding portions 25 the semicylindrical portions 24 of the casing 2 can also be prevented from being deformed.
  • the amount of movement of the slide valves 10, which are moved outward in radial directions by the pressure of the compression chambers 14 during the operation of the compressor is reduced.
  • the screw compressor 1 having the protruding portions 25 because the amount of movement of the slide valves 10 outward in radial directions can be reduced, the gap between the outer circumferential surface of the screw rotor 3 and the surface of the slide valves 10 facing the outer circumferential surface of the screw rotor 3 can be prevented from widening, and the performance of the compressor can thereby be prevented from being decreased.
  • protruding portions 25 in which at least each part of the end portion on the other side faces the inner circumferential wall 23a of the outer cylindrical portion 23, pressure loss generated by the protruding portions 25 serving as resistance to refrigerant gas when the refrigerant gas flows through the discharge flow passage 7 can be prevented from increasing, compared with the protruding portions 25 whose each end portion on the other side is coupled to and formed integrally with the outer cylindrical portion 23 as in Fig. 2 .
  • the protruding portions 25 each include, in a radial direction RD of the rotating shaft 5, the end portion on one side formed integrally with the intermediate inner cylindrical portion 22 and the end portion on the other side formed integrally with the outer cylindrical portion 23, and the protruding portions 25 each have a columnar shape connecting the intermediate inner cylindrical portion 22 and the outer cylindrical portion 23 to one another.
  • the casing 2 can ensure its strength, and strains can further be prevented or reduced compared with the configuration in which, in radial directions RD of the rotating shaft 5, the end portions of the protruding portions 25 on one side are each formed integrally with the intermediate inner cylindrical portion 22, and the end portions on the other side each face the inner circumferential wall 23a of the outer cylindrical portion 23.
  • the protruding portions 25 each have the same length as the semicylindrical portions 24 in the axial direction AD of the rotating shaft 5.
  • the casing 2 can further ensure its strength, and the cylindrical portion 20 can further be prevented from being strained.
  • Fig. 10 illustrates schematically a configuration of the screw compressor 1 according to Embodiment 2 and is a sectional view at the position of line A-A of Fig. 1 .
  • the configuration elements having the same functions and effects as the configuration elements of the screw compressor 1 according to Embodiment 1 are denoted by the same reference signs, and the description of such configuration elements will be omitted. Differences from Embodiment 1 will be described in Embodiment 2, and the configurations that are not described in Embodiment 2 are similar to the configurations of Embodiment 1.
  • the structure of the protruding portions 25 is further specified.
  • the protruding portions 25 of the screw compressor 1 according to Embodiment 2 each have a length smaller than the length of the semicylindrical portions 24 in the axial direction AD of the rotating shaft 5.
  • a length L1 is the length of the protruding portions 25 in the axial direction AD
  • a length L2 is the length of the semicylindrical portions 24 in the axial direction AD.
  • the cylindrical portion 20, which includes the intermediate inner cylindrical portion 22 and the inner cylindrical portion 21, can be prevented from being deformed, by the protruding portions 25 having a length smaller than the length of the semicylindrical portions 24.
  • pressure loss generated by the protruding portions 25 serving as resistance to refrigerant gas when the refrigerant gas flows through the discharge flow passage 7 can be prevented or reduced, by the protruding portions 25 having a length smaller than the length of the semicylindrical portions 24.
  • the screw compressor 1 having the protruding portions 25 can achieve, at the same time, prevention or reduction of deformation of the cylindrical portion 20 and prevention or reduction of pressure loss of the refrigerant flowing through the discharge flow passage 7 during the operation of the compressor, and such a high-performance screw compressor can thus be provided.
  • Fig. 11 is a front view of the screw compressor 1 according to Embodiment 3.
  • Fig. 12 illustrates schematically a configuration of the screw compressor 1 according to Embodiment 3 and is an enlarged sectional view at the position of line D-D of Fig. 11 .
  • each of the solid-line arrows represents a direction in which the high-pressure refrigerant gas discharged from each of the compression chambers 14 flows.
  • the configuration elements having the same functions and effects as the configuration elements of the screw compressors 1 according to Embodiments 1 and 2 are denoted by the same reference signs, and the description of such configuration elements will be omitted.
  • Embodiment 3 Differences from Embodiment 1 or Embodiment 2 will be described in Embodiment 3, and the configurations that are not described in Embodiment 3 are similar to the configurations of Embodiment 1 or Embodiment 2.
  • the structure of the protruding portions 25 is further specified.
  • a discharge-side end portion is the end portion 2a on one side (refer to Fig. 2 ) on which refrigerant is discharged
  • a suction-side end portion is the end portion 2b on the other side (refer to Fig. 2 ) on which refrigerant is sucked.
  • the protruding portions 25 of the screw compressor 1 according to Embodiment 3 each include a tapered portion 25a formed such that a width W1 of the protruding portion 25 decreases from the discharge-side end portion toward the suction-side end portion.
  • the protruding portions 25 may each be formed only by the tapered portion 25a. That is, the protruding portions 25 may each be formed such that the entirety of the protruding portion 25 is tapered toward the upstream side in a direction in which refrigerant flows.
  • each of the protruding portions 25 decreases gradually from the end on the downstream side of refrigerant gas in Fig. 12 , only a part of each of the protruding portions 25 on the upstream side of the flow passage of refrigerant gas may be tapered.
  • the protruding portions 25 may each have a part having the width W1 that is uniform from the discharge-side end portion toward the suction-side end portion and each may have the tapered portion 25a in a distal end part in a direction from the discharge-side end portion toward the suction-side end portion. That is, the protruding portions 25 may each be formed such that only the distal end part of the protruding portion 25 is tapered toward the upstream side in the direction in which refrigerant flows.
  • the cylindrical portion 20, which includes the intermediate inner cylindrical portion 22 and the inner cylindrical portion 21 can be prevented from being deformed, by the protruding portions 25 having the tapered portions 25a.
  • pressure loss generated by the protruding portions 25 serving as resistance to refrigerant gas when the refrigerant gas flows through the discharge flow passage 7 can be prevented or reduced, by the protruding portions 25 having the tapered portions 25a.
  • the screw compressor 1 having the protruding portions 25 can achieve, at the same time, prevention or reduction of deformation of the cylindrical portion 20 and prevention or reduction of pressure loss of the refrigerant flowing through the discharge flow passage 7 during the operation of the compressor, and such a high-performance screw compressor can thus be provided.
  • Fig. 13 is a schematic top view illustrating schematically a top face of the casing 2 of the screw compressor 1 according to Embodiment 4.
  • Fig. 14 is a schematic side view illustrating schematically a side face of the casing 2 of the screw compressor 1 according to Embodiment 4.
  • the configuration elements having the same functions and effects as the configuration elements of the screw compressors 1 according to Embodiments 1 to 3 are denoted by the same reference signs, and the description of such configuration elements will be omitted. Differences from Embodiments 1 to 3 will be described in Embodiment 4, and the configurations that are not described in Embodiment 4 are similar to the configurations of Embodiments 1 to 3.
  • the structure of the casing 2 is further specified.
  • the casing 2 of the screw compressor 1 according to Embodiment 4 further includes outside protruding portions 26, which are each a wall extending in a radial direction RD of the rotating shaft 5 and in the axial direction AD of the rotating shaft 5 and protrude from the outer circumferential wall 22b of the intermediate inner cylindrical portion 22.
  • the outside protruding portions 26 each include, in a radial direction RD of the rotating shaft 5, an end portion on one side formed integrally with the intermediate inner cylindrical portion 22 and an end portion on the other side protruding toward the outside of the casing 2, and the outside protruding portions 26 each have a height larger than the width of the outside protruding portion 26 in the circumferential direction CD.
  • the screw compressor 1 includes the motor 4 (refer to Fig. 2 ) coupled to the rotating shaft 5.
  • the casing 2 includes the motor accommodation portion 27 housing the motor 4.
  • the motor accommodation portion 27 is formed at a position apart from the outer cylindrical portion 23 in the axial direction AD.
  • the motor accommodation portion 27 is formed at the end portion other than the end portion at which the outer cylindrical portion 23 is disposed in the axial direction AD of the rotating shaft 5.
  • the motor accommodation portion 27 has a hollow cylindrical shape and has an outside diameter OD2 larger than an outside diameter OD1 of the intermediate inner cylindrical portion 22.
  • the outside protruding portions 26 are each formed integrally with the outer cylindrical portion 23 and the motor accommodation portion 27 such that the outside protruding portion 26 connects the outer cylindrical portion 23 and the motor accommodation portion 27 to one another. More specifically, the outside protruding portions 26 are each formed between the bottom wall portion 23c of the outer cylindrical portion 23 and the motor accommodation portion 27 in the axial direction AD of the rotating shaft 5.
  • the casing 2 has an upper part and a lower part and the outside protruding portion 26 is provided in each of the upper part and the lower part of the casing 2.
  • One of the outside protruding portions 26 provided in the upper part of the casing 2 protrudes at the upper portion of the casing 2.
  • the one of the outside protruding portions 26 provided in the upper part of the casing 2 is preferably formed on an upper apex portion of the intermediate inner cylindrical portion 22.
  • Another one of the outside protruding portions 26 provided in the lower part of the casing 2 protrudes at the lower portion of the casing 2.
  • the other one of the outside protruding portions 26 provided in the lower part of the casing 2 is preferably formed on a lower apex portion of the intermediate inner cylindrical portion 22.
  • the casing 2 preferably includes the one outside protruding portion 26 protruding upward and the other outside protruding portion 26 protruding downward, the casing 2 may have only one of the outside protruding portions 26.
  • the outside protruding portions 26 are each a wall extending in a radial direction RD of the rotating shaft 5 and in the axial direction AD of the rotating shaft 5.
  • each of the outside protruding portions 26 is a part of the casing 2 and has a width W3, in the circumferential direction CD of the rotating shaft 5, smaller than a length L3 of the outside protruding portion 26 in the axial direction AD of the rotating shaft 5. That is, as Fig. 13 illustrates, the length L3 of each outside protruding portion 26 in the axial direction AD of the rotating shaft 5 is larger than the width W3 of each outside protruding portion 26 in the circumferential direction CD of the rotating shaft 5.
  • the outside protruding portions 26 are each provided in a direction G orthogonal to a straight line F connecting centers E of the pair of gate rotors 6 (not illustrated).
  • the length L3 which is a length of each of the outside protruding portions 26 in the axial direction, is larger than a diameter D1 of each of the gate rotors 6 (refer to Fig. 6 ).
  • the screw compressor 1 includes the gate rotors 6 and the screw rotor 3 within a range in which the outside protruding portions 26 are formed.
  • a casing of a screw compressor is required to have, in the axial direction of a rotating shaft, a length enough to house components such as a screw rotor, a motor, and the rotating shaft.
  • a pressure resistance test or the operation of the compressor when pressure acts on an inner side of the casing, local stress concentration occurs on the casing serving as the contour due to the structure of the casing required to have a certain length in the axial direction, and the casing may thereby be bent in radial directions including the vertical direction. More specifically, when viewed in a vertical section of the casing taken in the axial direction of the rotating shaft, the casing may be bent into a U shape such that a center part of the casing bulges.
  • a cylindrical portion formed in an inner part of the casing is also displaced in the vertical direction or in a radial direction, and the roundness of the cylindrical portion increases.
  • the casing is required to have a space for housing a gate rotor and its circumferential components (not illustrated), and a wall face of the casing defining the space is thereby likely to have a low rigidity and is thus likely to be deformed.
  • the casing 2 of the screw compressor 1 according to Embodiment 4 includes the outside protruding portions 26.
  • Each of the outside protruding portions 26 includes, in a radial direction RD of the rotating shaft 5, the end portion on one side formed integrally with the intermediate inner cylindrical portion 22 and the end portion on the other side protruding toward the outside of the casing 2.
  • the casing 2 of the screw compressor 1 having the outside protruding portions 26 can be increased in rigidity compared with a case where no outside protruding portions 26 are provided. In the screw compressor 1, when internal pressure is applied to the casing 2, the rigidity is ensured by the presence of the outside protruding portions 26, and local stress concentration on the casing 2 is thereby reduced.
  • the screw compressor 1 because such local stress concentration on the casing 2 is reduced by the outside protruding portions 26 when internal pressure is applied to the casing 2, the intermediate inner cylindrical portion 22, which is a part of the casing 2, is prevented from being displaced, that is, the roundness is prevented from increasing.
  • plastic deformation caused by a pressure resistance test or elastic deformation caused during the operation of the compressor can be prevented or reduced, and permanent strain that remains in the casing 2 after the load is removed can be reduced.
  • the outside protruding portions 26 are each formed integrally with the outer cylindrical portion 23 and the motor accommodation portion 27 such that the outside protruding portions 26 each connect the outer cylindrical portion 23 and the motor accommodation portion 27 to one another.
  • the rigidity of the casing 2 can further be increased compared with a casing not having the above-described configuration.
  • the casing 2 of the screw compressor 1 including the outside protruding portions 26 can be prevented from being bent in the vertical direction or in radial directions compared with a case where no outside protruding portions 26 are provided.
  • the outside protruding portions 26 are each a part of the casing 2 and each have the width W3, in the circumferential direction CD of the rotating shaft 5, smaller than the length L3 of each of the outside protruding portions 26 in the axial direction AD of the rotating shaft 5. That is, the length L3 of each outside protruding portion 26 in the axial direction AD of the rotating shaft 5 is larger than the width W3 of each outside protruding portion 26 in the circumferential direction CD of the rotating shaft 5. Accordingly, the wall of each outside protruding portion 26 has a thickness, in the axial direction AD of the rotating shaft 5, larger than the thickness of the outside protruding portion 26 in the circumferential direction CD of the rotating shaft 5.
  • the casing 2 of the screw compressor 1 having the outside protruding portions 26 can be increased in rigidity compared with a case where no outside protruding portions 26 are provided, and the casing 2 can thereby be prevented from being bent in the vertical direction or radial directions.
  • Fig. 15 is a schematic top view illustrating schematically a top face of the casing 2 of the screw compressor 1 according to Embodiment 5.
  • the configuration elements having the same functions and effects as the configuration elements of the screw compressors 1 according to Embodiments 1 to 4 are denoted by the same reference signs, and the description of such configuration elements will be omitted. Differences from Embodiments 1 to 4 will be described in Embodiment 5, and the configurations that are not described in Embodiment 5 are similar to the configurations of Embodiments 1 to 4.
  • the structure of the outside protruding portions 26 is further specified.
  • a discharge-side end portion is the end portion 2a on one side on which refrigerant is discharged
  • a suction-side end portion is the end portion 2b on the other side on which refrigerant is sucked.
  • the outside protruding portions 26 are each formed such that a width W3 of the outside protruding portion 26 decreases gradually from the discharge-side end portion toward the suction-side end portion.
  • the outside protruding portions 26 are each formed such that the width W3 of the outside protruding portion 26 decreases gradually from the discharge-side end portion toward the suction-side end portion.
  • Fig. 16 is a schematic top view illustrating schematically a top face of the casing 2 of the screw compressor 1 according to Embodiment 6.
  • Fig. 17 is a schematic side view illustrating schematically a side face of the casing 2 of the screw compressor 1 according to Embodiment 6.
  • the configuration elements having the same functions and effects as the configuration elements of the screw compressors 1 according to Embodiments 1 to 5 are denoted by the same reference signs, and the description of such configuration elements will be omitted. Differences from Embodiments 1 to 5 will be described in Embodiment 6, and the configurations that are not described in Embodiment 6 are similar to the configurations of Embodiments 1 to 5.
  • the structure of the outside protruding portions 26 is further specified.
  • the outside protruding portions 26 each include a lower protruding portion 26a protruding from the intermediate inner cylindrical portion 22 and an upper protruding portion 26b protruding from the lower protruding portion 26a. Of one of the outside protruding portions 26 that protrudes upward from the intermediate inner cylindrical portion 22, the lower protruding portion 26a protrudes upward from the intermediate inner cylindrical portion 22, and the upper protruding portion 26b protrudes upward from the lower protruding portion 26a.
  • the lower protruding portion 26a protrudes downward from the intermediate inner cylindrical portion 22
  • the upper protruding portion 26b protrudes downward from the lower protruding portion 26a.
  • the lower protruding portion 26a has a width W4, in the circumferential direction CD of the rotating shaft 5 (refer to Fig. 1 ), larger than a width W5 of the upper protruding portion 26b in the circumferential direction CD of the rotating shaft 5.
  • the lower protruding portion 26a has a height H1, in a radial direction RD of the rotating shaft 5, smaller than a height H2 of the upper protruding portion 26b in the radial direction RD of the rotating shaft 5.
  • a height is a length of each of the outside protruding portions 26 in a radial direction RD.
  • the outside protruding portions 26 each include the lower protruding portion 26a protruding from the intermediate inner cylindrical portion 22 and the upper protruding portion 26b protruding from the lower protruding portion 26a.
  • the screw compressor 1 having the above-described configuration enables increase in the major axis-side rigidity of the casing 2, which may be deformed into an oval shape by internal pressure, thereby enabling prevention or reduction of deformation of the casing 2 caused by internal pressure.
  • the width W4 of the lower protruding portion 26a in the circumferential direction CD of the rotating shaft 5 is larger than the width W5 of the upper protruding portion 26b in the circumferential direction CD of the rotating shaft 5.
  • the height H1 of the lower protruding portion 26a in a radial direction RD of the rotating shaft 5 is smaller than the height H2 of the upper protruding portion 26b in the radial direction RD of the rotating shaft 5.
  • the outside protruding portions 26 each including the lower protruding portion 26a and the upper protruding portion 26b which have the above-described configurations, enables reduction of a material to be used compared with a case where the entire outside protruding portions 26 each have the width W4 of the lower protruding portion 26a.
  • the material costs can be reduced while the rigidity is ensured.
  • Fig. 18 is a schematic side view illustrating schematically a side face of the casing 2 of the screw compressor 1 according to Embodiment 7.
  • a schematic top view of the casing 2 of the screw compressor 1 according to Embodiment 7 is similar to the schematic top view illustrated in Fig. 13 or Fig. 15 .
  • the configuration elements having the same functions and effects as the configuration elements of the screw compressors 1 according to Embodiments 1 to 6 are denoted by the same reference signs, and the description of such configuration elements will be omitted. Differences from Embodiments 1 to 6 will be described in Embodiment 7, and the configurations that are not described in Embodiment 7 are similar to the configurations of Embodiments 1 to 6.
  • the structure of the outside protruding portions 26 according to Embodiment 5 is further specified.
  • a discharge-side end portion is the end portion 2a on one side on which refrigerant is discharged
  • a suction-side end portion is the end portion 2b on the other side on which refrigerant is sucked.
  • the outside protruding portions 26 are each formed such that a height H of the outside protruding portion 26 decreases gradually from the discharge-side end portion toward the suction-side end portion.
  • the outside protruding portions 26 are each formed such that the height H of the outside protruding portion 26 increases gradually from the motor accommodation portion 27 side toward the discharge-side end portion.
  • the outside protruding portions 26 are each formed such that the height H of the outside protruding portion 26 increases gradually from the motor accommodation portion 27 side toward the discharge-side end portion.
  • Embodiments 1 to 7 described above may be implemented in combination with one another.
  • the configurations represented by the above-described embodiments are examples and may be combined with another known technique, and a part of the configurations may be omitted or changed without departing from the spirit.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
EP21946952.5A 2021-06-21 2021-06-21 SCREW COMPRESSORS Pending EP4361444A4 (en)

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JP5024163B2 (ja) 2008-03-31 2012-09-12 ダイキン工業株式会社 圧縮機の製造方法
JP2011132835A (ja) * 2009-12-22 2011-07-07 Daikin Industries Ltd スクリュー圧縮機
JP6705200B2 (ja) * 2016-02-17 2020-06-03 ダイキン工業株式会社 スクリュー圧縮機
JP6332336B2 (ja) * 2016-06-14 2018-05-30 ダイキン工業株式会社 スクリュー圧縮機
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