Screw compressor and refrigeration device

Abstract

This screw compressor comprises: a compression mechanism that has a screw rotor and compresses a refrigerant; a motor that rotates the screw rotor and includes a coil and a stator core; an inverter that supplies electric power to the motor and is cooled by a liquid refrigerant; and a casing that has a suction chamber into which the refrigerant is introduced from the outside, a rotor chamber that accommodates the compression mechanism, and a motor chamber that accommodates the motor and is positioned between the suction chamber and the rotor chamber. The liquid refrigerant that has cooled the inverter is supplied to a coil end of the coil or to the stator core.

Description

Screw Compressor and Refrigeration Device

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

[0002] Patent Document 1 discloses a screw compressor that cools the coil ends of the stator coil of a motor with the inhaled fluid.

[0003] Japanese Patent Application Laid-Open No. 2005-057916

[0004] In a screw compressor that cools the motor coil and stator core with the inhaled refrigerant gas, when the specific gravity of the refrigerant gas is small, the temperature of the refrigerant gas rises significantly during the process of cooling the motor. Since the temperature of the refrigerant gas rises significantly, the temperature of the motor may become high downstream of the motor.

[0005] The present disclosure provides a screw compressor that enhances the cooling effect of the motor by the refrigerant.

[0006] The screw compressor of the first aspect has a screw rotor, a compression mechanism that compresses a refrigerant, a motor that rotates the screw rotor and includes a coil and a stator core, an inverter that supplies power to the motor and is cooled by liquid refrigerant, a casing that has a suction chamber for introducing refrigerant from the outside, a rotor chamber that houses the compression mechanism, and a motor chamber that houses the motor and is located between the suction chamber and the rotor chamber, and the liquid refrigerant that has cooled the inverter is supplied to the coil end of the coil or the stator core.

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

[0008] The screw compressor of the second aspect is the screw compressor of the first aspect in which the liquid refrigerant supplied to the coil end or the stator core is supplied from one location or a plurality of locations in the circumferential direction.

[0009] According to the screw compressor of the second aspect, the cooling effect of the motor can be further enhanced by discharging the refrigerant from one location or a plurality of locations in the circumferential direction.

[0010] The screw compressor of the third aspect is a screw compressor of either the first or second aspect in which the liquid refrigerant is supplied to the coil end on the suction chamber side of the coil.

[0011] According to the third perspective on screw compressors, supplying liquid refrigerant to the coil end on the intake chamber side can further enhance the cooling effect of the motor.

[0012] The screw compressor of the fourth aspect is a screw compressor of either the first or second aspect in which the liquid refrigerant is supplied to the coil end on the rotor chamber side of the coil.

[0013] According to the fourth perspective on screw compressors, supplying liquid refrigerant to the coil end on the rotor chamber side can further enhance the cooling effect of the motor.

[0014] A screw compressor according to the fifth viewpoint is a screw compressor according to the first or second viewpoint, comprising a terminal section to which external wiring is connected, the casing having a recess extending outward to which the terminal section is attached in the motor chamber, and the liquid refrigerant being supplied to the coil end or the stator core around the recess.

[0015] According to the screw compressor of the fifth perspective, by supplying liquid refrigerant to the recess where the terminal is attached, the rise in motor temperature caused by the accumulation of gaseous refrigerant in the recess can be suppressed.

[0016] The screw compressor of the sixth aspect is a screw compressor of any of the first to fifth aspects, in which the inverter is integrated into the casing.

[0017] According to the sixth perspective on screw compressors, it is possible to miniaturize screw compressors that can cool motors more efficiently.

[0018] The screw compressor of the seventh aspect is a screw compressor of any of the first to sixth aspects, wherein a second liquid refrigerant, different from the liquid refrigerant used to cool the inverter, is further supplied to the coil end or the stator core.

[0019] According to the screw compressor of the seventh perspective, the motor can be cooled more efficiently by further supplying a second liquid refrigerant that is different from the liquid refrigerant used to cool the inverter.

[0020] The screw compressor of the eighth aspect is a screw compressor of the seventh aspect in which the liquid refrigerant is supplied to the coil end or the stator core when the temperature of the inverter is at or above a first temperature, and the second liquid refrigerant is supplied to the coil end or the stator core when the motor is at or above a second temperature.

[0021] According to the screw compressor of the eighth perspective, the cooling of the inverter and motor can be made more efficient depending on the temperature of the inverter or motor.

[0022] The refrigeration system in the first perspective is a refrigeration system equipped with a screw compressor in any of the eighth perspectives.

[0023] According to the first aspect of the refrigeration system, the cooling effect of the motor by the refrigerant can be enhanced in the screw compressor equipped with the refrigeration system.

[0024] Figure 1 is a refrigerant circuit diagram of a refrigeration system using the screw compressor according to this embodiment. Figure 2 is a graph showing an example of the operating range of a refrigeration system using the screw compressor according to this embodiment. Figure 3 is a cross-sectional view of the screw compressor according to this embodiment. Figure 4 is a cross-sectional view of the screw compressor according to this embodiment. Figure 5 is a cross-sectional view of the cooling section in the screw compressor according to this embodiment. Figure 6 is a cross-sectional view of a first modified example of the screw compressor according to this embodiment. Figure 7 is a cross-sectional view of a second modified example of the screw compressor according to this embodiment. Figure 8 is a diagram illustrating the flow of liquid refrigerant in a third modified example of the screw compressor according to this embodiment. Figure 9 is a hardware configuration diagram showing the hardware configuration of a controller that controls the liquid refrigerant supplied to the third modified example of the screw compressor according to this embodiment. Figure 10 is a diagram illustrating the processing of a controller that controls the liquid refrigerant supplied to the third modified example of the screw compressor according to this embodiment.

[0025] <Refrigeration System> A refrigeration system using the screw compressor according to this embodiment will be described. Figure 1 is a refrigerant circuit diagram of a refrigeration system 10 using a screw compressor 1, which is an example of a screw compressor according to this embodiment. The refrigeration system 10 is, for example, a water heater or a chiller unit. Alternatively, the refrigeration system 10 may be, for example, an air conditioning system.

[0026] 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.

[0027] The screw compressor 1 comprises a generally cylindrical casing 14 with an inlet 14a and a discharge port 14e. The screw compressor 1 also comprises an inverter unit 19 that drives a motor. 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.

[0028] The refrigerant R, in the state of a high-pressure gas discharged from the discharge port 14e of the screw compressor 1, releases heat and condenses in the radiator 3. The refrigerant R, which has condensed in the radiator 3 into 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 (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.

[0029] 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 and inverter unit 19 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.

[0030] 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.

[0031] Figure 2 is a graph showing an example of the operating range of a refrigeration system 10 using a 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 a screw compressor 1 using, for example, R454C as the refrigerant R.

[0032] 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, that is, 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.

[0033] <Embodiments> A screw compressor according to this embodiment will be described below with reference to the drawings. This disclosure is not limited to these examples, but is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The screw compressor according to this embodiment comprises a compression mechanism having a screw rotor for compressing a refrigerant, a motor that rotates the screw rotor and includes a coil and a stator core, an inverter that supplies power to the motor and is cooled by liquid refrigerant, 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. In the screw compressor according to this embodiment, liquid refrigerant that has cooled the inverter is supplied to the coil end of the coil or the stator core.

[0038] In the screw compressor according to this embodiment, the liquid refrigerant that has cooled the inverter directly cools the coil ends and stator core of the coil. Also, in the screw compressor according to this embodiment, the motor and compression mechanism are housed in a casing. In the screw compressor according to this embodiment, the intake chamber, motor chamber and rotor chamber are in communication with each other. In the screw compressor according to this embodiment, the refrigerant introduced from the outside flows in the order of intake chamber, motor chamber and rotor chamber, and is compressed in the compression mechanism.

[0039] Figure 3 is a cross-sectional view of a screw compressor 1, which is an example of a screw compressor according to this embodiment.

[0040] 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, when a coordinate axis perpendicular to the plane of the drawing is shown with a black circle inside, it indicates that the coordinate axis is pointing towards the viewer relative to the plane of the drawing. Conversely, when a coordinate axis is shown with an X inside, it indicates that the coordinate axis is pointing away from the plane of the drawing.

[0041] However, the coordinate system is defined for the purpose of explanation and does not limit the posture of the screw compressor or the like according to the present embodiment.

[0042] In the following drawings, the X-axis direction is defined as the direction along which the rotation shaft 12 extends.

[0043] The screw compressor 1 compresses the refrigerant R in a low-pressure gas state. As described above, the screw compressor 1 includes a generally cylindrical casing 14 provided with a suction port 14a and a discharge port 14e. The screw compressor 1 compresses the refrigerant R in a low-pressure gas state sucked from the suction port 14a. Then, the screw compressor 1 discharges the refrigerant R in a high-pressure gas state from the discharge port 14e.

[0044] The screw compressor 1 includes a compression mechanism 11, a rotation shaft 12, a motor 13, a casing 14, and first bearings 15A, second bearings 15B, and third bearings 15C. Further, the screw compressor 1 includes an inverter unit 19.

[0045] The screw compressor 1 is characterized by having a configuration for solving the following problems. In the operating range of the screw compressor 1 shown by the solid line in FIG. 2, in the operating range with a lower SST and a higher SDT than the operating range of the conventional screw compressor shown by the broken line, the density of the sucked refrigerant R decreases. When the density of the refrigerant R decreases, the flow rate of the refrigerant R decreases as the volumetric efficiency decreases. Since the refrigerant R decreases, the cooling capacity of the motor 13 by the refrigerant R decreases. Therefore, the temperature of the motor 13 may rise, resulting in failure or a shortened lifespan.

[0046] Hereinafter, the configuration of each part of the screw compressor 1 for solving the above problems will be described in detail.

[0047] The casing 14 has a suction chamber 141, a motor chamber 142, a rotor chamber 143, and a discharge chamber 144.

[0048] The casing 14 is decomposably configured into three parts: a first part 14A that forms the suction chamber 141, a second part 14B that forms the motor chamber 142 and the rotor chamber 143, and a third part 14C that forms the discharge chamber 144. That is, the screw compressor 1 has a semi-hermetic configuration.

[0049] In the first part 14A of the casing 14 that forms the suction chamber 141, a suction port 14a through which the refrigerant R in the state of low-pressure gas flowing out from the evaporator 7 is sucked is provided. A bottomed cylindrical filter 14f is attached to the suction port 14a, for example. The suction chamber 141 sucks the refrigerant R in the state of low-pressure gas through the suction port 14a and the filter 14f when the refrigerant R is compressed by the compression mechanism 11. Further, the first part 14A of the casing 14 has a plurality of ribs 14r1 that radially extend in the radial direction of the rotary shaft 12 around the rotary shaft 12. The radial ribs 14r1 support the first bearing 15A at the central portion.

[0050] The motor chamber 142 is provided adjacent to the suction chamber 141. The motor chamber 142 houses the motor 13. The motor 13 includes a rotor 131 fixed to the rotary shaft 12 and a stator 132 disposed around the rotor 131. Permanent magnets are embedded in the rotor 131. A coil is wound around the stator 132. At the end of the stator 132 on the rotor chamber 143 side in the axial direction (X-axis direction) of the rotary shaft 12, a coil end 132c is formed by a coil protruding from the stator 132. Also, at the end of the stator 132 on the suction chamber 141 side in the axial direction (X-axis direction) of the rotary shaft 12, a coil end 132e is formed by a coil protruding from the stator 132.

[0051] The motor chamber 142 has, for example, a cylindrical inner wall surface having a predetermined interval from the outer peripheral surface of the stator 132, and a plurality of convex portions that protrude radially inward from the inner wall surface to support the stator 132. The plurality of convex portions of the motor chamber 142 that support the stator 132 are provided at equal intervals in the radial direction of the inner peripheral surface of the motor chamber 142 and extend along the rotary shaft 12.

[0052] An inverter unit 19 is provided on the second portion 14B 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 the screw compressor 1, the inverter unit 19 is provided as an integral part of the casing 14. Note that in Figure 3, the inverter 191 and cover 193 are not shown, and their approximate shapes are indicated by dashed lines.

[0053] The inverter 191 is connected to the motor 13, for example, via a terminal section 191a. The inverter 191 supplies power to the motor 13. The cooling section 192 is, for example, a metal plate-shaped member with excellent thermal conductivity. The cooling section 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 section 192. The cover 193 is attached to the second section 14B of the casing 14.

[0054] The rotor chamber 143 is provided adjacent to the motor chamber 142. The rotor chamber 143 houses the compression mechanism 11. The compression mechanism 11 comprises a screw rotor 111. The compression mechanism 11 compresses the refrigerant R. More specifically, the compression mechanism 11 comprises 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.

[0055] The compression mechanism 11 compresses the refrigerant R by drawing it into a compression chamber formed by the spiral grooves of the screw rotor 111, the gate rotor 112, and the cylindrical inner wall surface provided in the second portion 14B 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 portion 14B and the third portion 14C of the casing 14.

[0056] 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.

[0057] 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.

[0058] The discharge chamber 144 discharges the refrigerant R, which has been compressed by the compression mechanism 11, to the outside.

[0059] Next, the flow path through which the refrigerant R that cools the inverter 191 in the casing 14 passes will be described. Figure 4 is a cross-sectional view of a screw compressor 1, which is an example of a screw compressor according to this embodiment. Specifically, Figure 4 is a cross-sectional view taken along line A-A in Figure 3. Figure 5 is a cross-sectional view of the cooling section 192 in the screw compressor 1, which is an example of a screw compressor according to this embodiment.

[0060] The cooling unit 192 has a flow path 192p inside, which runs from an intake port 192r for drawing in liquid refrigerant R to an outlet port 192q for discharging the refrigerant R to the casing 14. Liquid refrigerant R is supplied from the injection mechanism 8 to the intake port 192r. As shown by the arrowed line in Figure 5, the liquid refrigerant R supplied to the intake port 192r passes through the flow path 192p in the cooling unit 192 and is discharged to the casing 14 from the outlet port 192q. The flow path 192p is provided by branching inside the cooling unit 192 in accordance with the arrangement of the inverter 191 to be cooled.

[0061] The casing 14 has a flow path 14v that extends in the Z-axis direction and is connected to an outlet 192q that is connected to a flow path 192p through which the liquid refrigerant R in the cooling section 192 flows, and a flow path 14h that is connected to the flow path 14v and is formed along a plane parallel to the YZ plane. The flow path 14h is provided at an inclination toward the -Z side with respect to the Y-axis direction. The flow path 14h may also be provided along the Y-axis direction.

[0062] The liquid refrigerant R, which has cooled the inverter 191 by passing through the cooling section 192, passes through the flow paths 14v and 14h in the casing 14 and is discharged into the motor chamber 142. The liquid refrigerant R discharged into the motor chamber 142 is supplied to the coil end 132c of the coil on the rotor chamber 143 side or to the stator core 132d. In the example of the screw compressor 1, the liquid refrigerant R is supplied to the coil end 132c of the coil on the rotor chamber 143 side or to the stator core 132d, but it may also be supplied to the coil end 132e of the coil on the suction chamber 141 side or to the stator core 132d.

[0063] In the screw compressor 1, liquid refrigerant R is supplied to the coil end 132c or stator core 132d from one location. The liquid refrigerant R supplied to the coil end 132c or stator core 132d cools the coil end 132c or stator core 132d. By cooling the coil end 132c or stator core 132d in the inverter unit 19, the screw compressor 1 can efficiently cool the motor.

[0064] According to the screw compressor of this embodiment, the motor can be efficiently cooled by using the liquid refrigerant that has cooled the inverter to cool the motor.

[0065] <First Modified Example> A first modified example of the screw compressor according to this embodiment will be described. In the first modified example of the screw compressor according to this embodiment, liquid refrigerant is supplied from multiple locations in the circumferential direction.

[0066] Figure 6 is a cross-sectional view of screw compressor 1A, which is an example of a first modified example of the screw compressor according to this embodiment.

[0067] The screw compressor 1A is equipped with a casing 114 in place of the casing 14 in the screw compressor 1. The casing 114 includes a plurality of flow paths 114v extending along the Z-axis and a plurality of flow paths 114h extending along the Y-axis. The plurality of flow paths 114v and the plurality of flow paths 114h intersect so that liquid refrigerant R flows through each of the plurality of flow paths 114v and the plurality of flow paths 114h. Liquid refrigerant R is supplied from a refrigerant supply port (not shown) provided in the casing 114. The refrigerant R supplied to the refrigerant supply port provided in the casing 114 is the refrigerant R that has cooled the inverter unit 19.

[0068] Liquid refrigerant R supplied from a refrigerant supply port in the casing 114 flows through multiple channels 114v and multiple channels 114h, filling each of them. The liquid refrigerant R that has flowed through each of the multiple channels 114v and multiple channels 114h is then supplied to the coil end 132c or stator core 132d of the stator 132 of the motor 13.

[0069] The casing 114 is supplied with liquid refrigerant R from multiple locations in the circumferential direction. By supplying liquid refrigerant R from multiple locations, the motor 13 can be cooled more efficiently.

[0070] <Second Modification> A second modification of the screw compressor according to this embodiment will be described. In the second modification of the screw compressor according to this embodiment, the casing has a motor chamber to which the terminal portion is attached and which has a recess that extends outward, and the liquid refrigerant is supplied to the coil end or stator core around the recess.

[0071] Figure 7 is a cross-sectional view of screw compressor 1B, which is an example of a second modified example of the screw compressor according to this embodiment.

[0072] The screw compressor 1B is equipped with a casing 214 in place of the casing 14. The casing 214 has a recess 145 extending outward from the motor chamber 142, into which a terminal portion 191a to which external wiring is connected is attached. The recess 145 is provided so that the terminals of the terminal portion 191a do not interfere with components provided inside the casing 214, such as the motor 13.

[0073] The casing 214 has a flow path 214h that extends in the X-axis direction and has one end connected to a recess 145. The flow path 214h is supplied with refrigerant R that has cooled the inverter unit 19 from a refrigerant supply port provided in the casing 214. The supplied refrigerant R is supplied to the recess 145 through the flow path 214h. The refrigerant R supplied to the recess 145 cools the gaseous refrigerant R that is retained in the recess 145. The refrigerant R supplied to the recess 145 is also supplied to the coil end 132e or stator core 132d on the intake chamber 141 side. The refrigerant R supplied to the coil end 132e or stator core 132d on the intake chamber 141 side cools the coil end 132e or stator core 132d.

[0074] The screw compressor 1B can suppress the temperature rise caused by the stagnation of gaseous refrigerant R in the recess 145 by supplying liquid refrigerant R from the recess 145 to which the terminal portion 191a of the casing 214 is attached.

[0075] <Third Modification> A third modification of the screw compressor according to this embodiment will be described. In the third modification of the screw compressor according to this embodiment, a second liquid refrigerant different from the liquid refrigerant used to cool the inverter is supplied to the coil end or stator core.

[0076] Figure 8 illustrates the flow of refrigerant in a screw compressor 1C, which is an example of a third modified example of the screw compressor according to this embodiment. The screw compressor 1C is equipped with a casing 314 instead of the casing 14 in the screw compressor 1. Furthermore, the screw compressor 1C is equipped with a controller 9C instead of the controller 9 in the screw compressor 1. The controller 9C has all the functions of the controller 9.

[0077] As shown in Figure 8, the refrigerant R supplied from the injection piping 81 is divided into refrigerant R1, which cools the inverter 191 by passing through the cooling section 192 in the inverter unit 19, and refrigerant R2, which is supplied directly from the injection piping 81 to the casing 14.

[0078] Refrigerant R1 is supplied to the motor chamber 142 after cooling the inverter 191 through the cooling section 192. Specifically, refrigerant R1 is supplied to the coil ends 132c, 132e, or stator core 132d of the motor 13. Refrigerant R2 is supplied directly to the motor chamber 142 from the injection piping 81. Specifically, refrigerant R2 is supplied to the coil ends 132c, 132e, or stator core 132d of the motor 13.

[0079] The screw compressor 1C is equipped with a solenoid valve 85 between the injection piping 81 and the cooling section 192. Furthermore, the screw compressor 1C is equipped with a solenoid valve 86 between the injection piping 81 and the casing 314.

[0080] Controller 9C will now be described. In addition to the functions of controller 9, controller 9C has the function of controlling solenoid valves 85 and 86. Figure 9 is a hardware configuration diagram showing the hardware configuration of controller 9C, which controls the liquid refrigerant supplied to screw compressor 1C, which is an example of a third modified example of the screw compressor according to this embodiment.

[0081] The controller 9C comprises a control unit 91, a RAM (Random Access Memory) 92, and a ROM (Read Only Memory) 93. The controller 9C also includes a storage interface 94 and an external interface 95. The control unit 91, RAM 92, ROM 93, storage interface 94, and external interface 95 are each connected to bus B1.

[0082] For example, a storage medium 94a is connected to the storage I / F 94. For example, solenoid valves 85 and 86 are connected to the external I / F 95. In addition, for example, a temperature sensor for measuring the temperature of inverter 191 and motor 13 is connected to the external I / F 95.

[0083] The control unit 91 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 91 may also be an ASIC (application specific integrated circuit) or an FPGA (Field-Programmable Gate Array). The control unit 91 executes a program, thereby performing each of the processes described herein. The control unit 91 is an arithmetic unit that reads a program (app, application) from a storage device such as a ROM 93 or a storage medium 94a onto the RAM 92 and executes processing. The control unit 91, RAM 92, and ROM 93 constitute a computer.

[0084] RAM92 is a volatile semiconductor memory that temporarily holds programs (apps, applications), for example.

[0085] ROM93 is a non-volatile semiconductor memory that can retain programs (apps, applications, etc.) even when the power is turned off. ROM93 stores programs such as the BIOS (Basic Input / Output System) that are executed at startup, as well as various settings such as OS (Operating System) settings and network settings.

[0086] The storage I / F 94 is an interface with an external storage device such as a storage medium 94a.

[0087] The storage medium 94a is, for example, an SD (Secure Digital) memory card, a USB (Universal Serial Bus) memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive).

[0088] The external I / F 95 is an interface that connects the solenoid valves 85 and 86 to the control unit 91. The control unit 91 controls the solenoid valves 85 and 86 via the external I / F 95.

[0089] The processing of the controller that controls the liquid refrigerant supplied to a third modified example of the screw compressor according to this embodiment will be described. Figure 10 is a diagram illustrating the processing of the controller 9C that controls the liquid refrigerant supplied to a screw compressor 1C, which is an example of a third modified example of the screw compressor according to this embodiment.

[0090] (Step S10) First, the control unit 91 determines whether the temperature in the inverter 191 is equal to or greater than a first temperature. The first temperature is, for example, 40°C. If the temperature in the inverter 191 is equal to or greater than the first temperature (YES in step S10), the control unit 91 proceeds to step S20. If the temperature in the inverter 191 is less than the first temperature (NO in step S10), the control unit 91 proceeds to step S30.

[0091] (Step S20) If the temperature in the inverter 191 is equal to or higher than the first temperature (YES in Step S10), the control unit 91 controls the solenoid valve 85 to open. After controlling the solenoid valve 85 to open, the control unit 91 proceeds to Step S40. By opening the solenoid valve 85, refrigerant R1 is supplied to the cooling unit 192 in the inverter unit 19. The refrigerant R1 supplied to the cooling unit 192 cools the inverter 191 and is supplied to the motor chamber 142. The refrigerant R1 supplied to the motor chamber 142 is supplied to the coil ends 132c, coil ends 132e, or stator core 132d of the motor 13. The motor 13 is cooled by the supply of refrigerant R1 to the coil ends 132c, coil ends 132e, or stator core 132d of the motor 13.

[0092] (Step S30) If the temperature in the inverter 191 is below the first temperature (NO in step S10), the control unit 91 controls the solenoid valve 85 to close. After controlling the solenoid valve 85 to close, the control unit 91 proceeds to step S40. If the temperature of the inverter 191 is below the first temperature, it is determined that there is no need to cool the inverter 191. By closing the solenoid valve 85, the supply of refrigerant R1 to the cooling unit 192 in the inverter unit 19 is stopped.

[0093] (Step S40) Next, the control unit 91 determines whether the temperature in the motor 13 is equal to or greater than the second temperature. The second temperature is, for example, 100°C. If the temperature in the motor 13 is equal to or greater than the second temperature (YES in step S40), the control unit 91 proceeds to step S50. If the temperature in the motor 13 is less than the second temperature (NO in step S40), the control unit 91 proceeds to step S60.

[0094] (Step S50) If the temperature in the motor 13 is above the second temperature (YES in step S40), the control unit 91 controls the solenoid valve 86 to open. After controlling the solenoid valve 86 to open, the control unit 91 proceeds to step S70. By opening the solenoid valve 86, refrigerant R2 is supplied to the motor chamber 142. The refrigerant R2 supplied to the motor chamber 142 is supplied to the coil ends 132c, coil ends 132e, or stator core 132d of the motor 13. The motor 13 is cooled by the supply of refrigerant R2 to the coil ends 132c, coil ends 132e, or stator core 132d of the motor 13.

[0095] (Step S60) If the temperature of the motor 13 is below the second temperature (NO in step S40), the control unit 91 controls the solenoid valve 86 to close. After controlling the solenoid valve 86 to close, the control unit 91 proceeds to step S70. If the temperature of the motor 13 is below the second temperature, it is determined that there is no need to cool the motor 13. Alternatively, it is determined that the motor 13 is sufficiently cooled by supplying the refrigerant R1 to the motor 13 in the motor chamber 142. By closing the solenoid valve 86, the supply of refrigerant R2 to the motor chamber 142 is stopped.

[0096] (Step S70) The control unit 91 determines whether to continue processing. If processing is to be continued (YES in step S70), the control unit 91 proceeds to step S10. If processing is not to be continued (YES in step S70), the control unit 91 terminates processing.

[0097] While 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 some or all of other embodiments.

[0098] This application claims priority to Basic Patent Application No. 2024-161483, filed with the Japan Patent Office on September 18, 2024, the entire contents of which are incorporated herein by reference.

[0099] 1, 1A, 1B, 1C Screw compressor 2 Refrigerant circuit 3 Heat sink 4 First expansion valve 5 Gas-liquid separator 6 Second expansion valve 7 Evaporator 8 Injection mechanism 9, 9C Controller 10 Refrigeration system 11 Compression mechanism 12 Rotating shaft 13 Motor 14, 114, 214, 314 Casing 14a Inlet 14A First part 14B Second part 14C Third part 14e Outlet 14f Filter 14h, 14v, 114h, 114v, 214h Flow path 14r1 Rib 14r2 Rib 14s Support member 15A First bearing 15B Second bearing 15C Third bearing 111 Screw rotor 112 Gate rotor 131 Rotor 132 Stator 132c, 132e Coil ends 132d Stator core 141 Intake chamber 142 Motor chamber 143 Rotor chamber 144 Discharge chamber 145 Recess 191 Inverter 191a Terminal section 192 Cooling section 192p Flow path 192q Outlet 192r Intake 214h Flow path R, R1, R2 Refrigerants

Claims

1. A casing (14, 114, 214, 314) comprising: a compression mechanism (11) having a screw rotor (111) for compressing a refrigerant (R); a motor (13) that rotates the screw rotor (111) and comprises a coil and a stator core (132d); an inverter (191) that supplies power to the motor (13) and is cooled by liquid refrigerant (R); an intake chamber (141) for introducing refrigerant (R) from the outside; a rotor chamber (143) housing the compression mechanism (11); and a motor chamber (142) housing the motor (13) and located between the intake chamber (141) and the rotor chamber (143); wherein the liquid refrigerant (R) that has cooled the inverter (191) is supplied to the coil ends (132c, 132e) of the coil or the stator core (132d). Screw compressors (1, 1A, 1B, 1C).

2. The screw compressor (1A) according to claim 1, wherein the liquid refrigerant (R) supplied to the coil ends (132c, 132e) or the stator core (132d) is supplied from one location or multiple locations in the circumferential direction.

3. The screw compressor (1, 1A) according to claim 1 or claim 2, wherein the liquid refrigerant (R) is supplied to the coil end (132e) on the suction chamber (141) side of the coil.

4. The liquid refrigerant (R) is supplied to the coil end (132c) on the rotor chamber (143) side of the coil, the screw compressor (1B) according to claim 1 or claim 2.

5. A screw compressor (1B) according to claim 1 or claim 2, comprising a terminal section (191a) to which external wiring is connected, the casing (214) having a recess (145) that extends outward to which the terminal section (191a) is attached to the motor chamber (142), and the liquid refrigerant (R) is supplied to the coil end (132e) or the stator core (132d) around the recess (145).

6. The screw compressor (1, 1A, 1B, 1C) according to any one of claims 1 to 5, wherein the inverter (191) is integrated with the casing (14, 114, 214, 314).

7. A screw compressor (1C) according to any one of claims 1 to 6, wherein a second liquid refrigerant (R2) different from the liquid refrigerant (R1) used to cool the inverter (191) is further supplied to the coil end (132c, 132e) or the stator core (132d).

8. The screw compressor (1C) according to claim 7, wherein the liquid refrigerant (R1) is supplied to the coil ends (132c, 132e) or the stator core (132d) when the temperature of the inverter (191) is at or above a first temperature, and the second liquid refrigerant (R2) is supplied to the coil ends (132c, 132e) or the stator core (132d) when the motor (13) is at or above a second temperature.

9. A refrigeration apparatus (10) comprising a screw compressor (1, 1A, 1B, 1C) according to any one of claims 1 to 8.

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