Screw compressors and refrigeration systems

Abstract

This disclosure provides a screw compressor that enhances the cooling effect of a motor using a refrigerant. [Solution] A screw compressor comprising: a compression mechanism having a screw rotor for compressing a refrigerant; a rotating shaft to which the screw rotor is fixed; a motor for rotating the rotating shaft; an intake chamber for introducing refrigerant from the outside; a rotor chamber for housing the compression mechanism; and a motor chamber for housing the motor and located between the intake chamber and the rotor chamber, wherein the rotating shaft has a first flow path communicating with the intake chamber and extending along a first axial direction; and a second flow path communicating with the motor chamber and the first flow path and extending along a second direction intersecting the first direction.

Description

Technical Field

[0001] The present disclosure relates to a screw compressor and a refrigeration device.

Background Art

[0002] Patent Document 1 discloses a compressor in which a motor and a compression rotor of a compression section are sequentially arranged in a casing from the suction port side. Patent Document 1 discloses that by flowing the fluid inhaled from the suction port along the periphery of the coil end, the coil end is cooled as a whole with the fluid, thereby preventing a local temperature rise at the tip of the coil end and improving the reliability of the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0007] According to the screw compressor in the first perspective, the cooling effect of the motor by the refrigerant can be enhanced.

[0008] The screw compressor in the second view is the screw compressor in the first view, wherein the rotating shaft has a plurality of the second flow paths.

[0009] According to the second perspective on screw compressors, the cooling effect of the motor can be further enhanced by discharging refrigerant from multiple locations.

[0010] A screw compressor in the third aspect is a screw compressor according to the second aspect, wherein the plurality of the second flow paths are located at different positions in the first direction.

[0011] According to the third perspective on screw compressors, discharging the refrigerant over a wider area can further enhance the cooling effect of the motor.

[0012] The screw compressor of the fourth viewpoint is a screw compressor of either the second viewpoint or the third viewpoint in which the plurality of second flow paths are located at different positions in the circumferential direction of the rotation axis.

[0013] According to the screw compressor from the fourth perspective, by discharging the refrigerant over a wider area in the circumferential direction, the cooling effect of the motor in the circumferential direction can be further enhanced.

[0014] The screw compressor according to the fifth aspect is a screw compressor according to any one of the second to fourth aspects, in which the diameters of the plurality of second flow paths are different from each other.

[0015] According to the screw compressor of the fifth aspect, for example, by changing the amount of refrigerant discharged according to the degree of temperature of rise, the cooling of the motor can be made more efficient.

[0016] The screw compressor according to the sixth aspect is a screw compressor according to any one of the first to fifth aspects, in which the second flow path is provided so as to intersect with a plane perpendicular to the rotating shaft.

[0017] According to the screw compressor of the sixth aspect, by expanding the region where the refrigerant is discharged, the cooling of the motor can be made more efficient.

[0018] The screw compressor according to the seventh aspect is the screw compressor according to any one of the first to sixth aspects, in which the first flow path is provided at a position eccentric from the axis center of the rotating shaft.

[0019] According to the screw compressor of the seventh aspect, by providing the first flow path at a position eccentric from the axis center of the rotating shaft, the amount of refrigerant discharged can be increased, and the cooling of the motor can be made more efficient.

[0020] The screw compressor according to the eighth aspect is the screw compressor according to any one of the first to seventh aspects, in which the refrigerant contains at least one of R1234ze, R1234yf, ammonia, and propane as a refrigerant component.

[0021] The screw compressor according to the ninth aspect is the screw compressor according to any one of the first to eighth aspects, which operates under the condition that the compression ratio is 7 or more.

[0022] The refrigeration device according to the first aspect is a refrigeration device including the screw compressor according to any one of the first to ninth aspects.

Brief Description of the Drawings

[0023] [Figure 1] Figure 1 is a refrigerant circuit diagram of a refrigeration device in which the screw compressor according to the present embodiment is used. [Figure 2] Figure 2 is a graph showing an example of the operating range of a refrigeration device in which the screw compressor according to the present embodiment is used. [Figure 3] Figure 3 is a cross-sectional view of the screw compressor according to the present embodiment. [Figure 4] Figure 4 is an enlarged cross-sectional view around the rotating shaft of the screw compressor according to the present embodiment. [Figure 5] Figure 5 is an enlarged cross-sectional view around the rotating shaft in the first modification of the screw compressor according to the present embodiment. [Figure 6] Figure 6 is an enlarged cross-sectional view around the rotating shaft in the second modification of the screw compressor according to the present embodiment. [Figure 7] Figure 7 is an enlarged cross-sectional view around the rotating shaft in the third modification of the screw compressor according to the present embodiment. [Figure 8] Figure 8 is an enlarged cross-sectional view around the rotating shaft in the fourth modification of the screw compressor according to the present embodiment.

Embodiments for Carrying Out the Invention

[0024] <Refrigeration Device> The refrigeration device in which the screw compressor according to the present embodiment is used will be described. Figure 1 is a refrigerant circuit diagram of a refrigeration device 10 in which a screw compressor 1 which is an example of the screw compressor according to the present embodiment is used. The refrigeration device 10 is, for example, a water heater or a chiller unit. Further, the refrigeration device 10 may be, for example, an air conditioner.

[0025] The refrigeration system 10 has a refrigerant circuit 2 filled with refrigerant R. The refrigerant R includes, for example, at least one of R454C, R134a, R32, R1234ze, R1234yf, ammonia, and propane as refrigerant components. The refrigeration system 10 performs a vapor compression type refrigeration cycle. The refrigerant circuit 2 includes a screw compressor 1, a heat sink 3, a first expansion valve 4, a gas-liquid separator 5, a second expansion valve 6, an evaporator 7, an injection mechanism 8, and a controller 9. In Figure 1, solid arrows indicate the flow of refrigerant R in the refrigerant circuit 2, and dotted lines indicate the electrical connections between the controller 9 and each component.

[0026] The screw compressor 1 comprises a generally cylindrical casing 14 with an inlet 14a and a discharge port 14e. The screw compressor 1 compresses the refrigerant R in a low-pressure gas state drawn in from the inlet 14a and discharges the refrigerant R in a high-pressure gas state from the discharge port 14e. Details of the screw compressor 1 will be described later.

[0027] The refrigerant R, in the state of a high-pressure gas discharged from the discharge port 14e of the screw compressor 1, condenses in the radiator 3, releasing heat. The refrigerant R, which has condensed in the radiator 3 and become a high-pressure liquid refrigerant, is depressurized in the first expansion valve 4. The refrigerant R, depressurized in the first expansion valve 4, is separated into gas and liquid by the gas-liquid separator 5 and stored at the bottom of the gas-liquid separator 5. The refrigerant R, in the state of a liquid refrigerant stored at the bottom of the gas-liquid separator 5, flows out from the refrigerant outlet 51 of the gas-liquid separator 5 and is depressurized in the second expansion valve 6. The refrigerant R, depressurized in the second expansion valve 6, absorbs heat and evaporates in the evaporator 7. The refrigerant R evaporated in the evaporator 7 is drawn in as a low-pressure gas from the suction port 14a of the screw compressor 1.

[0028] The injection mechanism 8 includes an injection pipe 81, a solenoid valve 82, a branch pipe 83, and a flow control valve 84. One end of the injection pipe 81 is connected to an injection port 52 located at the bottom of the gas-liquid separator 5. The other end of the injection pipe 81 is connected to the casing 14 of the screw compressor 1. The solenoid valve 82 is located in the middle of the injection pipe 81. The solenoid valve 82 is controlled and opened / closed by the controller 9. The branch pipe 83 branches off from the injection pipe 81 between the solenoid valve 82 and the screw compressor 1. The branch pipe 83 is then connected to the refrigerant circuit between the evaporator 7 and the screw compressor 1. The flow control valve 84 is located in the middle of the branch pipe 83. The opening degree of the flow control valve 84 is controlled and adjusted by the controller 9.

[0029] The controller 9 opens the solenoid valve 82 and supplies liquid refrigerant R to the screw compressor 1 when the temperature of the refrigerant R discharged from the screw compressor 1 exceeds a predetermined threshold. The controller 9 also adjusts the opening degree of the flow control valve 84 according to the temperature of the refrigerant R discharged from the screw compressor 1, for example. The controller 9 adjusts the amount of refrigerant R supplied to the screw compressor 1 by the injection mechanism 8. The controller 9 then controls the temperature of the refrigerant R discharged from the screw compressor 1.

[0030] Figure 2 is a graph showing an example of the operating range of a refrigeration system 10 using screw compressor 1, which is an example of a screw compressor according to this embodiment. In the graph of Figure 2, the horizontal axis is the saturation suction temperature (SST), and the vertical axis is the saturation discharge temperature (SDT). In Figure 2, the dashed line shows the operating range of a conventional screw compressor using R134a as the refrigerant. In Figure 2, the solid line shows the operating range of screw compressor 1 using, for example, R454C as the refrigerant R.

[0031] In response to the increasing demand for replacing gas boilers with heat pump chillers due to international decarbonization efforts and energy uncertainty, there is a need to improve the performance of refrigeration equipment 10 that can also be used as a heat pump chiller. Specifically, there is a need to expand the operating range of the screw compressor 1 installed in the refrigeration equipment 10 to a lower SST and higher SDT operating range than conventional screw compressors, as shown by the arrows in Figure 2, i.e., to a region of low ambient temperature and high outlet water temperature. For example, the screw compressor according to this embodiment is required to operate under conditions where the compression ratio is 7 or higher. Also, for example, the screw compressor according to this embodiment is required to operate under conditions where the saturated suction temperature (SST) is less than 25°C. Furthermore, for example, the screw compressor according to this embodiment is required to operate under conditions where the saturated discharge temperature (SDT) is higher than 68°C or higher than 75°C.

[0032] <Embodiment> A screw compressor according to this embodiment will be described below with reference to the drawings. This disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope equivalent to the claims, as indicated by the claims.

[0033] In the description and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals, thereby omitting redundant explanations. Furthermore, for ease of understanding, the scale of each part in the drawings may differ from the actual scale.

[0034] A degree of deviation is permissible in directions such as parallel, right angles, orthogonal, horizontal, vertical, up and down, left and right, and front and back, as long as it does not impair the effects of the embodiment. The shape of the corners is not limited to right angles and may be rounded. Parallel, right angles, orthogonal, horizontal, and vertical may include approximately parallel, approximately right angles, approximately orthogonal, approximately horizontal, and approximately vertical, respectively.

[0035] For example, "approximately parallel" means that two lines or two planes can be treated as parallel to each other within a manufacturingly acceptable range, even if they are not perfectly parallel. Similarly, "approximately right angle," "approximately perpendicular," "approximately horizontal," and "approximately vertical" are intended to apply as long as the relative positions of the two lines or two planes are within a manufacturingly acceptable range.

[0036] The screw compressor according to this embodiment comprises a compression mechanism having a screw rotor for compressing a refrigerant, a rotating shaft to which the screw rotor is fixed, a motor for rotating the rotating shaft, and a casing. The casing in the screw compressor according to this embodiment has an intake chamber for introducing refrigerant from the outside, a rotor chamber for housing the compression mechanism, and a motor chamber for housing the motor and located between the intake chamber and the rotor chamber. The rotating shaft in the screw compressor according to this embodiment has a first flow path communicating with the intake chamber and extending along a first axial direction, and a second flow path communicating with the motor chamber and the first flow path and extending along a second direction intersecting the first direction.

[0037] Figure 3 is a cross-sectional view of a screw compressor 1, which is an example of a screw compressor according to this embodiment.

[0038] For ease of explanation, drawings sometimes include a virtual three-dimensional coordinate system (XYZ Cartesian coordinate system) consisting of mutually orthogonal X, Y, and Z axes (XYZ axes). For example, for coordinate axes perpendicular to the plane of the drawing, a black circle inside a circle indicates that the coordinate axis is pointing towards the viewer relative to the plane of the drawing. Conversely, an X inside a circle indicates that the coordinate axis is pointing away from the plane of the drawing.

[0039] However, this coordinate system is defined for illustrative purposes only and is not limited to the orientation of the screw compressor, etc., according to this embodiment.

[0040] In the following diagram, the X-axis direction is the direction in which the rotation axis 12 extends.

[0041] The screw compressor 1 compresses the refrigerant R in a low-pressure gas state. As described above, the screw compressor 1 comprises a generally cylindrical casing 14 provided with an inlet 14a and a discharge port 14e. The screw compressor 1 compresses the refrigerant R in a low-pressure gas state that is drawn in from the inlet 14a. Then, the screw compressor 1 discharges the refrigerant R in a high-pressure gas state from the discharge port 14e.

[0042] The screw compressor 1 comprises a compression mechanism 11, a rotating shaft 12, a motor 13, a casing 14, a first bearing 15A, a second bearing 15B, and a third bearing 15C. The screw compressor 1 also includes an inverter unit 19.

[0043] Screw compressor 1 is characterized by having a configuration that solves the following problems. In the operating range of screw compressor 1 shown by the solid line in Figure 2, in the operating range with a lower SST and higher SDT than the operating range of a conventional screw compressor shown by the dashed line, the density of the inhaled refrigerant R decreases and the weight flow rate of refrigerant R decreases. When the weight flow rate of refrigerant R decreases, the heat capacity of refrigerant R, which is the cooling medium for the motor, decreases, and the cooling capacity of the motor 13 by refrigerant R decreases. Consequently, the temperature of the motor 13 may rise, potentially leading to failure or a shortened lifespan.

[0044] The following describes in detail the configuration of each part of the screw compressor 1 that solves the aforementioned problems.

[0045] The casing 14 has an intake chamber 141, a motor chamber 142, a rotor chamber 143, and a discharge chamber 144.

[0046] The casing 14 is configured to be separable into three parts: a first part 14A that forms the intake chamber 141, a second part 14B that forms the motor chamber 142 and rotor chamber 143, and a third part 14C that forms the discharge chamber 144. In other words, the screw compressor 1 has a semi-enclosed configuration.

[0047] The first portion 14A of the casing 14 that forms the intake chamber 141 is provided with an intake port 14a into which the refrigerant R in the form of a low-pressure gas flowing out from the evaporator 7 is drawn in. For example, a bottomed cylindrical filter 14f is attached to the intake port 14a. The intake chamber 141 draws in the refrigerant R in the form of a low-pressure gas through the intake port 14a and the filter 14f when the refrigerant R is compressed by the compression mechanism 11. The first portion of the casing 14 also has a plurality of ribs 14r1 that extend radially in the radial direction of the rotation axis 12, with the rotation axis 12 as the center. The radial ribs 14r1 support the first bearing 15A at their center.

[0048] The motor chamber 142 is located adjacent to the intake chamber 141. The motor chamber 142 houses the motor 13. The motor 13 comprises a rotor 131 fixed to the rotating shaft 12 and a stator 132 arranged around the rotor 131. Permanent magnets are embedded in the rotor 131. Coils are wound around the stator 132. Coil ends 132c are formed at both ends of the stator 132 in the axial direction (X-axis direction) of the rotating shaft 12 by coils protruding from both ends of the stator 132.

[0049] The motor chamber 142 has, for example, a cylindrical inner wall surface having a predetermined distance from the outer circumferential surface of the stator 132, and a plurality of protrusions projecting radially inward from the inner wall surface to support the stator 132. The plurality of protrusions of the motor chamber 142 that support the stator 132 are provided at equal intervals in the radial direction of the inner circumferential surface of the motor chamber 142 and extend along the rotation axis 12.

[0050] An inverter unit 19 is provided on the second portion of the casing 14 that forms the motor chamber 142. The inverter unit 19 includes, for example, an inverter 191 that supplies power to the motor 13, a cooling unit 192 that cools the inverter 191, and a cover 193 that covers them. In Figure 3, the inverter 191 and cover 193 are not shown, and their approximate shapes are indicated by dashed lines.

[0051] The inverter 191 is connected to the motor 13, for example, via a terminal portion 191a. The inverter 191 then supplies power to the motor 13. The cooling portion 192 is, for example, a metal plate-shaped member with excellent thermal conductivity. The cooling portion 192 has a flow path through which the refrigerant R, in the state of liquid refrigerant supplied from the injection mechanism 8 shown in Figure 1 to the screw compressor 1, passes. The cover 193 is, for example, a resin member that covers the inverter 191 and the cooling portion 192. The cover 193 is attached to the second portion 14B of the casing 14.

[0052] The rotor chamber 143 is located adjacent to the motor chamber 142. The rotor chamber 143 houses the compression mechanism 11. The compression mechanism 11 includes a screw rotor 111. The compression mechanism 11 compresses the refrigerant R. More specifically, the compression mechanism 11 includes a screw rotor 111 fixed to the rotating shaft 12, and a gate rotor 112 that engages with a helical groove provided in the screw rotor 111 and rotates around an axis perpendicular to the rotating shaft 12.

[0053] The compression mechanism 11 compresses the refrigerant R by drawing it into a compression chamber formed by the helical grooves of the screw rotor 111, the gate rotor 112, and the cylindrical inner wall surface provided in the second part of the casing 14, as the screw rotor 111 rotates. Once the compression of the refrigerant R is complete, the compression chamber is connected to the discharge chamber 144 via passages provided in the second part 14B and the third part 14C of the casing 14.

[0054] Furthermore, the second portion 14B of the casing 14 has multiple ribs 14r2 arranged radially between the motor chamber 142 and the rotor chamber 143, similar to the multiple ribs 14r1 provided on the first portion 14A of the casing 14. The radially arranged multiple ribs 14r2 support the second bearing 15B at their center. The second portion 14B of the casing 14 also supports the third bearing 15C via a support member 14s. The support member 14s is supported by the inner wall of the second portion 14B of the casing 14, which together with the compression mechanism 11 forms a compression chamber, and is positioned adjacent to the partition wall of the third portion 14C of the casing 14.

[0055] The refrigerant R that flows from the intake chamber 141 into the motor chamber 142 passes between the inner surface of the motor chamber 142 and the stator 132, and between the rotor 131 and the stator 132. The refrigerant R that has passed between the inner surface of the motor chamber 142 and the stator 132, and between the rotor 131 and the stator 132, then flows into the rotor chamber 143 while cooling the motor 13. The refrigerant R, in the state of a high-pressure gas compressed in the compression chamber of the compression mechanism 11, is discharged to the discharge chamber 144 through passages provided in the second part 14B and the third part 14C of the casing 14.

[0056] The discharge chamber 144 discharges the refrigerant R, which has been compressed by the compression mechanism 11, to the outside.

[0057] The rotating shaft 12 will now be described in detail. Figure 4 is an enlarged cross-sectional view of the area around the rotating shaft 12 in a screw compressor 1, which is an example of a screw compressor according to this embodiment. The rotating shaft 12 has a main flow path 12m (first flow path) extending in the axial direction (X-axis direction) and a branch flow path 12b (second flow path) branching off from the main flow path 12m.

[0058] The main flow path 12m communicates with the intake chamber 141. The main flow path 12m is provided along the central axis AX of the rotating shaft 12. The main flow path 12m has an opening 12i that opens into the intake chamber 141. The refrigerant R flows into the main flow path 12m from the opening 12i.

[0059] The branch channel 12b is provided downstream of the rotating shaft 12. The branch channel 12b is provided perpendicular to the rotation axis of the rotating shaft 12. The refrigerant R that flows into the main channel 12m is discharged from the branch channel 12b toward the coil end 132c of the stator 132. Alternatively, the refrigerant R may be discharged from the branch channel 12b toward the stator core of the stator 132.

[0060] According to the screw compressor of this embodiment, the cooling effect of the refrigerant on the motor can be enhanced by cooling the motor with the refrigerant discharged from the second flow path of the rotating shaft.

[0061] <First variation> A first modified example of the screw compressor according to this embodiment, in which the rotation axis is different, will be described. Figure 5 is an enlarged cross-sectional view of the area around the rotation axis 212 in screw compressor 1A, which is an example of the first modified example of the screw compressor according to this embodiment. Screw compressor 1A is equipped with a rotation axis 212 in place of the rotation axis 12 of screw compressor 1. The rotation axis 212 has a main flow path 12m (first flow path) extending in the axial direction (X-axis direction), and branch flow paths 212b1, 212b2, and 212b3 branching off from the main flow path 12m. In other words, the rotation axis 212 in screw compressor 1A is equipped with a plurality of branch flow paths (second flow paths) whose positions in the axial direction (X-axis direction) are different from each other.

[0062] The main flow path 12m will be omitted here, as its description is limited to the explanation of the rotating shaft 12. The same applies to the following modified examples.

[0063] The branch channels 212b1, 212b2, and 212b3 are arranged in order from downstream along the axial direction of the rotating shaft 212. Furthermore, the diameters of each of the branch channels 212b1, 212b2, and 212b3 are different from each other.

[0064] According to the first modified example of the screw compressor according to this embodiment, the cooling effect of the motor by the refrigerant can be further enhanced by providing a plurality of second flow paths. Furthermore, according to the first modified example of the screw compressor according to this embodiment, the cooling effect of the motor by the refrigerant can be further enhanced over a wider range. Moreover, according to the first modified example of the screw compressor according to this embodiment, by making the diameters of the plurality of second flow paths different, the amount of refrigerant discharged can be changed according to the degree of temperature rise of the motor, thereby making the motor cooling more efficient.

[0065] <Second variation> A second modified example of the screw compressor according to this embodiment, in which the rotation axis is different, will be described. Figure 6 is an enlarged cross-sectional view of the area around the rotation axis 312 in screw compressor 1B, which is an example of the first modified example of the screw compressor according to this embodiment. Screw compressor 1B is equipped with a rotation axis 312 in place of the rotation axis 12 of screw compressor 1. The rotation axis 312 has a main flow path 12m extending in the axial direction (X-axis direction) and a branch flow path 312b branching off from the main flow path 12m.

[0066] The branch channel 312b is installed at an angle so as to intersect with a plane perpendicular to the axial direction (X-axis direction) (a plane parallel to the YZ plane).

[0067] According to a second modification of the screw compressor according to this embodiment, the cooling effect of the motor by the refrigerant can be further enhanced by widening the range over which the refrigerant is discharged.

[0068] <Third variation> A third modified example of the screw compressor according to this embodiment, in which the rotation axis is different, will be described. Figure 7 is an enlarged cross-sectional view of the area around the rotation axis 412 in screw compressor 1C, which is an example of the first modified example of the screw compressor according to this embodiment. Screw compressor 1C is equipped with a rotation axis 412 in place of the rotation axis 12 of screw compressor 1. The rotation axis 412 has a main flow path 12m extending in the axial direction (X-axis direction) and a plurality of branch flow paths 412b branching from the main flow path 12m.

[0069] Multiple branch channels 412b are provided at 90-degree intervals in the circumferential direction of the rotating shaft 412. That is, multiple branch channels 4 12 b is The positions in the circumferential direction are different.

[0070] According to a third modified example of the screw compressor in this embodiment, by providing a plurality of second flow paths in the circumferential direction of the rotating shaft, the cooling effect of the motor in the circumferential direction can be further enhanced.

[0071] <Fourth variation> A fourth modified example of the screw compressor according to this embodiment, in which the rotation axis is different, will be described. Figure 8 is an enlarged cross-sectional view of the area around the rotation axis 512 in screw compressor 1D, which is an example of the first modified example of the screw compressor according to this embodiment. Screw compressor 1D is equipped with a rotation axis 512 in place of the rotation axis 12 of screw compressor 1. The rotation axis 512 has a main flow path 512m extending in the axial direction (X-axis direction) and a branch flow path 512b branching off from the main flow path 512m.

[0072] The main flow path 512m is located on the intake chamber 141 side of the rotating shaft 512 and is connected to a recess 512n that is rotationally symmetrical with respect to the central axis AX of the rotating shaft 512. The main flow path 512m is located eccentrically with respect to the central axis AX of the rotating shaft 512.

[0073] A plate 512c with an opening 512i formed in the center is attached to the intake chamber 141 side of the recess 512n. The refrigerant R that flows in through the opening 512i flows through the recess 512n and into the main flow path 512m. Because the main flow path 512m is provided eccentrically with respect to the recess 512n, the main flow path 512m and the recess 512n act as an eccentric pump.

[0074] According to a fourth modification of the screw compressor according to this embodiment, by providing the first flow path at an eccentric position from the axis center of the rotating shaft and making it act as an eccentric pump, the amount of refrigerant discharged can be increased, thereby further enhancing the cooling effect of the motor by the refrigerant.

[0075] According to the screw compressor of this embodiment, the cooling effect of the motor by the refrigerant can be enhanced.

[0076] Although embodiments have been described above, it will be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. Various modifications and improvements are possible, such as combinations or substitutions with parts or all of other embodiments. [Explanation of Symbols]

[0077] 1, 1A, 1B, 1C, 1D Screw compressors 2 Refrigerant Circuit 3 Heat sink 4. First expansion valve 5 Gas-liquid separator 6. Second expansion valve 7 Evaporator 8. Injection mechanism 9 Controllers 10 Refrigeration equipment 11 Compression mechanism 12 rotation axes 12b, 212b1, 212b2, 212b3, 312b, 412b, 512b Branching channel 12i, 512i opening 12m, 512m main channel 512n recess 13 Motors 14 Casing 14a Inlet 14e Discharge port 14f filter 14r1, 14r2 Rib 14s Support member 15A First bearing 15B Second bearing 15C Third bearing 19 Inverter Unit 51 Refrigerant outlet 52 Injection Ports 81 Injection Piping 82 Solenoid valve 83 Branch piping 84 Flow control valve 111 Screw Rotor 112 Gate Rotor 131 Rotor 132 stata 132c coil end 141 Suction chamber 142 Motor Room 143 Rotor chamber 144 Discharge chamber 191 Inverter 191a Terminal section 192 Cooling section 193 Cover R refrigerant

Claims

1. A compression mechanism (11) having a screw rotor (111) for compressing a refrigerant (R), The screw rotor (111) is fixed to the rotating shafts (12, 212, 312, 412, 512), A motor (13) that rotates the aforementioned rotating shafts (12, 212, 312, 412, 512), A casing (14) having an intake chamber (141) for introducing the refrigerant (R) from the outside, a rotor chamber (143) for housing the compression mechanism (11), and a motor chamber (142) for housing the motor (13) and located between the intake chamber (141) and the rotor chamber (143), Equipped with, The aforementioned rotating shafts (12, 212, 312, 412, 512) are A first flow path (12m, 512m) is in communication with the aforementioned intake chamber (141) and extends along the first axial direction (X-axis direction), It has a second flow path (12b, 212b1, 212b2, 212b3, 312b, 412b, 512b) that communicates with the motor chamber (142) and the first flow path (12m, 512m) and extends along a second direction intersecting the first direction (X-axis direction), The refrigerant (R) is introduced from the intake chamber (141) through the motor chamber (142) to the rotor chamber (143). Screw compressors (1, 1A, 1B, 1C, 1D).

2. The rotating shaft (212, 412) comprises a plurality of the second flow channels (212b1, 212b2, 212b3, 412b), The screw compressor (1A, 1C) according to claim 1.

3. The multiple second channels (212b1, 212b2, 212b3) are located at different positions in the first direction (X-axis direction). The screw compressor (1A) according to claim 2.

4. The multiple second flow channels (412b) are located at different positions in the circumferential direction of the rotating shaft (412). The screw compressor (1C) according to claim 2.

5. The diameters of each of the multiple second channels (212b1, 212b2, 212b3) are different from each other. The screw compressor (1A) according to claim 2.

6. The second flow channels (212b3, 312b) are provided at an angle so as to intersect with a plane perpendicular to the rotation axis (212, 312). The screw compressor (1A, 1B) according to claim 1.

7. The first flow path (512m) is provided at an eccentric position from the axial center (AX) of the rotating shaft (512). The screw compressor (1D) according to claim 1.

8. The refrigerant (R) comprises at least one of R1234ze, R1234yf, ammonia, and propane as refrigerant components. The screw compressor (1, 1A, 1B, 1C, 1D) according to claim 1.

9. Operate under conditions where the compression ratio is 7 or higher. The screw compressor (1, 1A, 1B, 1C, 1D) according to claim 1.

10. A refrigeration apparatus (10) comprising a screw compressor (1, 1A, 1B, 1C, 1D) according to any one of claims 1 to 9.

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