Compressor and refrigeration device

Abstract

A compressor (10) compresses refrigerant. The compressor includes an electric motor (20) and a compression mechanism (30) operated by the electric motor. The compression mechanism is provided with an impeller (31) that rotates by the electric motor. The electric motor comprises a drive shaft (21), a rotor (22) fixed to the drive shaft, and a stator (23) disposed on the outer circumferential side (R1) of the rotor. The drive shaft and the rotor include a refrigerant passage (40) through which the refrigerant flows. The refrigerant passage has: a shaft passage (50) that extends inside (21i) of the drive shaft from a first direction side (X1) in the axial direction (X) to a second direction side (X2) in which the impeller is disposed; and a communication passage (60) that communicates a gap (A) between the rotor and the stator with the shaft passage.

Description

Compressors and refrigeration equipment

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

[0002] For example, Patent Document 1 discloses various techniques for electric motors for operating compressors and pumps. The electric motor includes a drive shaft, a rotor fixed to the drive shaft, and a stator disposed radially outward of the rotor.

[0003] Japanese Patent Application Laid-Open No. 2020-159538

[0004] When an electric motor is in operation, the rotor and stator generate heat, so they need to be cooled by some means. In conventional electric motors, it has not been possible to effectively cool the rotor and stator.

[0005] An object of the present disclosure is to effectively cool the rotor and stator in an electric motor.

[0006] A first aspect of the present disclosure is directed to a compressor (10). The compressor (10) compresses a refrigerant (W). The compressor (10) includes an electric motor (20) and a compression mechanism (30) operated by the electric motor (20). The compression mechanism (30) includes an impeller (31) rotated by the electric motor (20). The electric motor (20) includes a drive shaft (21), a rotor (22) fixed to the drive shaft (21), and a stator (23) arranged on the outer circumferential side (R1) of the rotor (22). The drive shaft (21) and the rotor (22) are arranged in a direction perpendicular to the axial direction of the impeller (31). 2) includes a refrigerant passage (40) through which the refrigerant (W) flows, and the refrigerant passage (40) has an axial passage (50) extending through an interior (21i) of the drive shaft (21) from a first direction side (X1) in the axial direction (X) to a second direction side (X2) which is opposite to the first direction side (X1) and on which the impeller (31) is arranged, and a communication passage (60) which communicates between a gap (A) between the rotor (22) and the stator (23) and the axial passage (50).

[0007] According to the first aspect, the refrigerant (W) is more easily supplied to the gap (A) between the rotor (22) and the stator (23) of the electric motor (20), thereby effectively cooling the rotor (22) and the stator (23) of the electric motor (20).

[0008] A second aspect of the present disclosure is directed to the compressor (10) according to the first aspect, wherein the axial passage (50) opens to a first axial end surface (21 a) of the drive shaft (21) on the first side (X1) in the axial direction (X) of the drive shaft (21).

[0009] According to the second aspect, the refrigerant (W) flows into the axial passage (50) from the first axial end surface (21a) of the drive shaft (21), and flows through the axial passage (50) from the first direction side (X1) to the second direction side (X2) in the axial direction (X). The refrigerant (W) can be smoothly flowed into the axial passage (50).

[0010] A third aspect of the present disclosure is directed to the compressor (10) according to the first or second aspect. The communication passage (60) opens to an outer peripheral surface (22a) of the rotor (22).

[0011] According to the third aspect, the refrigerant (W) flows from the axial passage (50) into the communicating passage (60) and flows through the communicating passage (60) toward the outer periphery (R1) due to the centrifugal force of the drive shaft (21) and the rotor (22). The refrigerant (W) is supplied from the outer periphery (22a) of the rotor (22) to the gap (A) between the rotor (22) and the stator (23). The refrigerant (W) can be smoothly supplied to the gap (A) between the rotor (22) and the stator (23) of the electric motor (20).

[0012] A fourth aspect of the present disclosure is directed to a compressor (10) according to any one of the first to third aspects. A length from a first rotor end face (22b) on the first direction side (X1) of the rotor (22) in the axial direction (X) to a second rotor end face (22c) on the second direction side (X2) is defined as L, and the rotor (22) is divided into a first region (C1) configured from the first rotor end face (22b) toward the second rotor end face (22c) in the axial direction (X) up to ¼L, and a second region (C2) configured from the second rotor end face (22c) toward the first rotor end face (22b) in the axial direction (X) up to ¼L. and a third region (C3) constituted by a portion of ½L between the first region (C1) and the second region (C2), a first passage volume (V1) per unit length in the axial direction (X) of the communicating passage (60) in the first region (C1) or a second passage volume (V2) per unit length in the axial direction (X) of the communicating passage (60) in the second region (C2) is larger than a third passage volume (V3) per unit length in the axial direction (X) of the communicating passage (60) in the third region (C3).

[0013] According to the fourth aspect, by making the first passage volume (V1) or the second passage volume (V2) larger than the third passage volume (V3), the refrigerant (W) can be supplied intensively to the gap (A) between the rotor (22) and the stator (23) in the first region (C1) or the second region (C2) compared to the third region (C3).

[0014] A fifth aspect of the present disclosure is directed to the compressor (10) according to the fourth aspect, wherein a first average cross-sectional area (S1) of the communicating passage (60) in the first region (C1) or a second average cross-sectional area (S2) of the communicating passage (60) in the second region (C2) is greater than a third average cross-sectional area (S3) of the communicating passage (60) in the third region (C3).

[0015] According to the fifth aspect, by making the first average cross-sectional area (S1) or the second average cross-sectional area (S2) larger than the third average cross-sectional area (S3), the first passage volume (V1) or the second passage volume (V2) can be easily made larger than the third passage volume (V3).

[0016] A sixth aspect of the present disclosure is directed to the compressor (10) according to the fourth aspect, wherein a first interval (P1) between the communicating passages (60) adjacent to each other in the axial direction (X) in the first region (C1) or a second interval (P2) between the communicating passages (60) adjacent to each other in the axial direction (X) in the second region (C2) is smaller than a third interval (P3) between the communicating passages (60) adjacent to each other in the axial direction (X) in the third region (C3).

[0017] According to the sixth aspect, by making the first interval (P1) or the second interval (P2) smaller than the third interval (P3), the first passage volume (V1) or the second passage volume (V2) can be easily made larger than the third passage volume (V3).

[0018] A seventh aspect of the present disclosure is directed to the compressor (10) according to any one of the second to sixth aspects. When a length from a first rotor end face (22b) on the first direction side (X1) in the axial direction (X) of the rotor (22) to a second rotor end face (22c) on the second direction side (X2) is defined as L, the communicating passage (60) that is furthest from the first rotor end face (22b) toward the second rotor end face (22c) in the axial direction (X) of the rotor (22) is arranged at a distance of ¼L or more from the first rotor end face (22b) toward the second rotor end face (22c) in the axial direction (X) of the rotor (22).

[0019] According to the seventh aspect, the rotor (22) and the stator (23) can be cooled by the refrigerant (W) even in an area far away from the first axial end surface (21a) of the drive shaft (21) (the opening of the axial passage (50)) on the second direction side (X2) in the axial direction (X).

[0020] An eighth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to seventh aspects. The communication passage (60) is arranged on both the first direction side (X1) and the second direction side (X2) of a center (22m) in the axial direction (X) of the rotor (22).

[0021] According to the eighth aspect, the rotor (22) and the stator (23) can be cooled by the refrigerant (W) in both the region on the first direction side (X1) and the region on the second direction side (X2) of the center (22m) in the axial direction (X) of the rotor (22).

[0022] A ninth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to eighth aspects. The communicating passage (60), as viewed in the axial direction (X), extends so as to intersect with a straight line (E) extending from an axial center (O) of the drive shaft (21) to a connection point (B) between the communicating passage (60) and the axial passage (50).

[0023] According to the ninth aspect, by turning the refrigerant (W) flowing through the communication passage (60), not only the centrifugal force of the drive shaft (21) and the rotor (22) but also axial power can be applied to the refrigerant (W) flowing through the communication passage (60). This makes it easier to supply the refrigerant (W) to the gap (A) between the rotor (22) and the stator (23).

[0024] A tenth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to ninth aspects. The axial passage (50) is configured in an annular shape so as to surround an axial center (O) of the drive shaft (21) as viewed in the axial direction (X).

[0025] According to the tenth aspect, the axial center (0) of the drive shaft (21) surrounded by the annular axial passage (50) is formed of a thick portion, thereby ensuring the strength of the drive shaft (21).

[0026] An eleventh aspect of the present disclosure is directed to the compressor (10) according to any one of the first to tenth aspects. The axial passage (50) is formed in a tapered shape such that the diameter thereof decreases as the axial passage (50) extends from the first direction side (X1) to the second direction side (X2) in the axial direction.

[0027] According to the eleventh aspect, the refrigerant (W) can be throttled as it flows through the axial passage (50) from the first direction side (X1) to the second direction side (X2). This makes it possible to prevent the refrigerant (W) from being difficult to send from the axial passage (50) to the communicating passage (60) due to a decrease in pressure of the refrigerant (W) on the second direction side (X2) of the axial passage (50).

[0028] A twelfth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to eleventh aspects. The electric motor (20) includes a casing (24) that houses the drive shaft (21), the rotor (22), and the stator (23), the casing (24) includes a discharge passage (25) that discharges the refrigerant (W) from the refrigerant passage (40), and the discharge passage (25) is provided with a pump (26) that promotes the discharge of the refrigerant (W).

[0029] According to the twelfth aspect, the refrigerant (W) can be smoothly discharged from the refrigerant passage (40) through the discharge passage (25) by the pump (26).

[0030] A thirteenth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to twelfth aspects. The electric motor (20) includes a cooler (2) that cools the refrigerant (W) before the refrigerant (W) flows into the refrigerant passage (40).

[0031] According to the thirteenth aspect, the refrigerant (W) is cooled by the cooler (2) before flowing into the refrigerant passage (40), which is advantageous in cooling the rotor (22) and the stator (23) with the refrigerant (W).

[0032] A fourteenth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to thirteenth aspects. The communication passage (60) is arranged at only one specific position (G) in the axial direction (X).

[0033] According to the fourteenth aspect, the number of holes to be drilled in the rotor (22) for forming the communication passages (60) can be reduced, thereby suppressing a decrease in the performance of the electric motor (20).

[0034] A fifteenth aspect of the present disclosure is directed to the compressor (10) according to any one of the first to fourteenth aspects. When a length from a first rotor end face (22b) on the first direction side (X1) of the rotor (22) in the axial direction (X) to a second rotor end face (22c) on the second direction side (X2) is defined as L, and the rotor (22) is divided into a first region (C1) consisting of a portion extending from the first rotor end face (22b) to the second rotor end face (22c) in the axial direction (X) up to ¼L, a second region (C2) consisting of a portion extending from the second rotor end face (22c) to the first rotor end face (22b) in the axial direction (X) up to ¼L, and a third region (C3) consisting of a portion extending ½L between the first region (C1) and the second region (C2), the communicating passage (60) is arranged only in the first region (C1) or only in the second region (C2).

[0035] Since the communication passage (60) is disposed only in the first region (C1) or only in the second region (C2), the communication passage (60) is disposed only near the first rotor end face (22b) or only near the second rotor end face (22c). This reduces the number of holes to be drilled in the rotor (22) to form the communication passages (60), thereby suppressing a decrease in performance of the electric motor (20).

[0036] A sixteenth aspect of the present disclosure is directed to a refrigeration system (1). The refrigeration system (1) includes the compressor (10) according to any one of the first to fifteenth aspects.

[0037] FIG. 1 shows an electric motor (20), a compressor (10), and a refrigeration system (1) according to a first embodiment. FIG. 2 shows a cross-sectional view of the electric motor (20) according to the first embodiment. FIG. 3 shows an enlarged cross-sectional view of the electric motor (20) according to the first embodiment. FIG. 4 shows a cross-sectional view of the electric motor (20) according to the first embodiment, viewed in the axial direction (X). FIG. 5 shows an enlarged cross-sectional view of the electric motor (20) according to a second embodiment. FIG. 6 shows an enlarged cross-sectional view of the electric motor (20) according to a third embodiment. FIG. 7 shows an enlarged cross-sectional view of the electric motor (20) according to a fourth embodiment. FIG. 8 shows an enlarged cross-sectional view of the electric motor (20) according to a fifth embodiment. FIG. 9 shows an enlarged cross-sectional view of the electric motor (20) according to a sixth embodiment. FIG. 10 shows an enlarged cross-sectional view of the electric motor (20) according to a seventh embodiment. FIG. 11 shows a cross-sectional view of the electric motor (20) according to the seventh embodiment, viewed in the axial direction (X). Fig. 12 shows a cross-sectional view of an electric motor (20) according to an eighth embodiment, as viewed in the axial direction (X). Fig. 13 shows an enlarged cross-sectional view of an electric motor (20) according to a ninth embodiment. Fig. 14 shows an enlarged cross-sectional view of an electric motor (20) according to a tenth embodiment. Fig. 15 shows an enlarged cross-sectional view of an electric motor (20) according to an eleventh embodiment. Fig. 16 shows an enlarged cross-sectional view of an electric motor (20) according to a twelfth embodiment.

[0038] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0039] First Embodiment (Refrigeration Device) An electric motor (20), a compressor (10), and a refrigeration device (1) according to a first embodiment will be described. FIG. 1 shows the electric motor (20), the compressor (10), and the refrigeration device (1). The refrigeration device (1) includes a refrigerant circuit. A refrigerant (W) circulates in the refrigeration circuit of the refrigeration device (1). The refrigeration circuit of the refrigeration device (1) includes a compressor (10), a condenser (2), a pressure reduction mechanism (expansion mechanism) (3), and an evaporator (4).

[0040] The compressor (10) compresses the refrigerant (W). Specifically, the compressor (10) compresses the low-temperature, low-pressure gaseous refrigerant (W) to a high-temperature, high-pressure state. The condenser (2) cools the high-temperature, high-pressure gaseous refrigerant (W) to condense and liquefy it into a low-temperature, low-pressure liquid. The condenser (2) is an example of the cooler (2) in this example. The pressure reduction mechanism (3) reduces the pressure of the low-temperature, high-pressure liquid refrigerant (W) to a low-temperature, low-pressure liquid. The pressure reduction mechanism (3) is, for example, an expansion valve or a capillary tube. The evaporator (4) evaporates the low-temperature, low-pressure liquid refrigerant (W) to a low-temperature, low-pressure gaseous state.

[0041] In FIG. 1, of the refrigerant (W) circulating through the refrigerant circuit of the refrigeration system (1), a high-pressure refrigerant (W1) is indicated by a solid line, and a low-pressure refrigerant (W2) is indicated by a dashed line.

[0042] (Compressor) The compressor (10) is a turbo compressor. The compressor (10) compresses the refrigerant (W) to a high pressure by centrifugal force of an impeller (31) described later. The compressor (10) includes an electric motor (20) and a compression mechanism (30).

[0043] (Electric Motor) The electric motor (20) includes a drive shaft (21), a rotor (22), a stator (23), a casing (24), a touchdown bearing (27), and a thrust magnetic bearing (28). The drive shaft (21) and the casing (24) are shared by the electric motor (20) and the compression mechanism (30). In this example, the rotor (22) and the stator (23) function as a bearingless motor, and therefore no radial bearing is required.

[0044] Hereinafter, the direction in which the axial center (O) of the drive shaft (21) extends is referred to as the axial direction (X). One side in the axial direction (X) (the left side in FIG. 2 ) is referred to as the rear side (X1). The rear side (X1) is an example of the first direction side (X1) in this example. The other side in the axial direction (X) (the right side in FIG. 2 ) is referred to as the front side (X2). The front side (X2) is an example of the second direction side (X2) in this example. The front side (X2) is the side on which the compression mechanism (30), such as the impeller (31), is disposed. The rear side (X1) is the side opposite to the side on which the compression mechanism (30), such as the impeller (31), is disposed. In the axial direction (X), the front side (X2) is opposite the rear side (X1), and the rear side (X1) is opposite the front side (X2). A direction perpendicular to the axial center (O) of the drive shaft (21) is referred to as the radial direction (R). The outside of the radial direction (R) is called the outer circumferential side (R1). The inside of the radial direction (R) is called the inner circumferential side (R2).

[0045] The drive shaft (21) is rod-shaped with a circular cross section and extends in the axial direction (X).

[0046] The rotor (22) is cylindrical and extends in the axial direction (X). The rotor (22) is fixed to the drive shaft (21). The rotor (22) rotates in conjunction with the rotation of the drive shaft (21). The stator (23) is cylindrical and extends in the axial direction (X). The stator (23) is disposed on the outer circumferential side (R1) of the rotor (22) in the radial direction (R).

[0047] A gap (A) is formed between the outer peripheral surface (22a) of the rotor (22) and the inner peripheral surface (23a) of the stator (23). In the electric motor (20), the drive shaft (21) and the rotor (22) rotate together relative to the stator (23) and the casing (24).

[0048] The casing (24) is formed in a cylindrical shape with both ends closed. The casing (24) extends in the axial direction (X). The casing (24) accommodates the drive shaft (21), the rotor (22), the stator (23), the touchdown bearing (27), the thrust magnetic bearing (28), and the impeller (31).

[0049] The space within the casing (24) is partitioned by a wall (24a). The space in front (X2) of the wall (24a) forms an impeller chamber (24b). The space behind (X1) of the wall (24a) forms an electric motor chamber (24c). The impeller (31) is accommodated in the impeller chamber (24b). The rotor (22), the stator (23), the touchdown bearing (27), and the thrust magnetic bearing (28) are accommodated in the electric motor chamber (24c). The drive shaft (21) penetrates the wall (24a) and is accommodated in both the impeller chamber (24b) and the electric motor chamber (24c).

[0050] The stator (23) is fixed to the inner peripheral surface of the casing (24). There are two touchdown bearings (27). The two touchdown bearings (27) are arranged spaced apart from each other in the axial direction (X). The touchdown bearings (27) are fixed to the casing (24). The touchdown bearings (27) support the drive shaft (21) in the radial direction (R) when the rotor (22) and the stator (23) do not function as a bearingless motor (when not energized).

[0051] The thrust magnetic bearing (28) has two electromagnets (28a). The two electromagnets (28a) are fixed to the casing (24). The two electromagnets (28a) support, by electromagnetic force, a disk portion (28b) provided at the rear end of the drive shaft (21) in a non-contact manner.

[0052] (Compression Mechanism) The compression mechanism (30) is located forward (X2) of the electric motor (20) in the axial direction (X). The compression mechanism (30) includes an impeller (31). The impeller (31) is fixed to a drive shaft (21) of the electric motor (20). The impeller (31) is rotated by the electric motor (20). More specifically, the rotation of the drive shaft (21) of the electric motor (20) rotates the impeller (31) of the compression mechanism (30). The compression mechanism (30) is driven by the electric motor (20). The compression mechanism (30) compresses the refrigerant (W).

[0053] The impeller (31) is fixed to the front end of the drive shaft (21) and accommodated in the impeller chamber (24b). A suction pipe (24d) and a discharge pipe (24e) are connected to the impeller chamber (24b). A compression space (24f) is formed on the outer periphery of the impeller chamber (24b). The suction pipe (24d) introduces low-pressure refrigerant (W) from the outside into the impeller chamber (24b). The discharge pipe (24e) returns the high-pressure refrigerant (W) compressed in the impeller chamber (24b) to the outside.

[0054] (Refrigerant Passage) The refrigerant passage (40) will be described with reference to Figures 2 and 3. Figure 2 shows a cross-sectional view of the electric motor (20) according to the first embodiment (taken along line II in Figure 4). Figure 3 shows an enlarged cross-sectional view of the electric motor (20) according to the first embodiment (enlarged view of Figure 2). For simplicity, Figures 2 and 3 omit some components of the electric motor (20) and change dimensions and the like from those shown in Figure 1.

[0055] The drive shaft (21) and the rotor (22) include a refrigerant passage (40). A refrigerant (W) flows through the refrigerant passage (40). The refrigerant passage (40) includes an axial passage (50) and a communication passage (60).

[0056] The shaft passage (50) extends through the interior (21i) of the drive shaft (21) from the rear side (X1) to the front side (X2) in the axial direction (X).

[0057] The rear end (51) of the axial passage (50) opens to a rear axial end face (21a) on the rear side (X1) in the axial direction (X) of the drive shaft (21). The rear axial end face (21a) is an example of a first axial end face (21a) in this example. In the axial direction (X), the rear end (51) of the axial passage (50) is located at the same position as the rear axial end face (21a) of the drive shaft (21).

[0058] The front end (52) of the axial passage (50) is located midway through the interior (21i) of the drive shaft (21). The front end (52) of the axial passage (50) is located rearward (X1) in the axial direction (X) from the front axial end face (21b) of the drive shaft (21) (which is fitted into the impeller (31) in FIG. 1). The front axial end face (21b) is an example of a second axial end face in this example.

[0059] The diameter (d) of the axial passage (50) is constant from the rear side (X1) to the front side (X2) in the axial direction (X).

[0060] The communicating passage (60) extends through the interior (21i) of the drive shaft (21) and the interior of the rotor (22) from the inner peripheral side (R2) to the outer peripheral side (R1) in the radial direction (R). The outer end (61) of the communicating passage (60) opens to the outer peripheral surface (22a) of the rotor (22). The outer end (61) of the communicating passage (60) faces the gap (A) between the outer peripheral surface (22a) of the rotor (22) and the inner peripheral surface (23a) of the stator (23). The inner end (62) of the communicating passage (60) faces the axial passage (50) in the interior (21i) of the drive shaft (21). The communicating passage (60) connects the gap (A) between the rotor (22) and the stator (23) with the axial passage (50).

[0061] The length from the rear rotor end face (22b) on the rear side (X1) to the front rotor end face (22c) on the front side (X2) in the axial direction (X) of the rotor (22) is defined as L. The rear rotor end face (22b) is an example of the first rotor end face (22b) in this example. The rear rotor end face (22b) faces the rear side (X1). The front rotor end face (22c) is an example of the second rotor end face (22c). The front rotor end face (22c) faces the front side (X2).

[0062] The rear rotor end face (22b) and the front rotor end face (22c) are disposed within the casing (24). The rear rotor end face (22b) of the rotor (22) is located forward (X2) in the axial direction (X) of the rear shaft end face (21a) of the drive shaft (21). The front rotor end face (22c) of the rotor (22) is located rearward (X1) in the axial direction (X) of the front shaft end face (21b) of the drive shaft (21).

[0063] There are a plurality of communicating passages (60). The communicating passages (60) are arranged side by side in the axial direction (X). The communicating passages (60) are arranged side by side in the circumferential direction around the axis (O) (see FIG. 4 ). The communicating passages (60) have a constant cross-sectional area. The communicating passages (60) adjacent to each other in the axial direction (X) have a constant interval (pitch). The communicating passages (60) have a constant passage volume (the volume of the passage for the refrigerant (W) from the inlet (axial passage (50) side) of the communicating passage (60) to the outlet (gap (A) side)).

[0064] The first communication passage (60a), which is the communication passage (60) that is the farthest from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22), is arranged at a distance of 1 / 4L or more from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22).

[0065] Specifically, the first communication passage (60a) is disposed at a distance of ½L or more from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22). More specifically, the first communication passage (60a) is disposed at a distance of ¾L or more from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22). In practice, the first communication passage (60a) is disposed slightly before (slightly behind (X1)) the front rotor end face (22c) and at a distance slightly less than L (slightly less than L) from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22).

[0066] The communication passages (60) are arranged on both the rear side (X1) and the front side (X2) in the axial direction (X) of the rotor (22) relative to the center (22m) (1 / 2L) in the axial direction (X).

[0067] 4 is a cross-sectional view of the electric motor (20) according to the first embodiment (taken along line IV in FIG. 2) as viewed in the axial direction (X). The axial passage (50) is configured in a circular shape centered on the axial center (O) of the drive shaft (21) as viewed in the axial direction (X).

[0068] The communicating passage (60) extends substantially along the radial direction (R). More specifically, when viewed in the axial direction (X), the communicating passage (60) overlaps without intersecting with a straight line (E) extending from the axial center (O) of the drive shaft (21) to a connection point (B) between the communicating passage (60) and the axial passage (50).

[0069] (Discharge Passage) Returning to Figures 2 and 3, the casing (24) includes a discharge passage (25). The discharge passage (25) is a discharge pipe provided in the outer peripheral wall (24g) of the casing (24). The discharge passage (25) extends in the radial direction (R). The discharge passage (25) is disposed on the outer peripheral side (R1) of the outer peripheral surface (22a) of the rotor (22). The discharge passage (25) is disposed on the axial direction (X) forward side (X2) of the front rotor end face (22c) of the rotor (22). The discharge passage (25) discharges the refrigerant (W) from the refrigerant passage (40).

[0070] (Refrigerant Flow) The flow of the refrigerant (W) will be described with reference to FIGS. 1 to 3. The low-temperature, low-pressure gaseous refrigerant (W) flows into the compressor (10). The refrigerant (W) is compressed in the compressor (10) to become a high-temperature, high-pressure gaseous refrigerant. Next, the high-temperature, high-pressure gaseous refrigerant (W) flows into the condenser (2). The refrigerant (W) is cooled in the condenser (2) to become a low-temperature, high-pressure liquid refrigerant. Next, a portion of the low-temperature, high-pressure liquid refrigerant (W) that has passed through the condenser (2) is decompressed in the decompression mechanism (3) to become a low-temperature, low-pressure liquid refrigerant, and is further evaporated in the evaporator (4) to become a low-temperature, low-pressure gaseous refrigerant, which is returned to the compressor (10).

[0071] The other part of the low-temperature, high-pressure refrigerant (W) that has passed through the condenser (2) is introduced into the refrigerant passage (40) of the electric motor (20) of the compressor (10). Specifically, as shown in Fig. 3, the low-temperature, high-pressure refrigerant (W) flows from an opening in the rear end surface (21a) of the drive shaft (21) into the rear end (51) of the axial passage (50). The refrigerant (W) flows through the axial passage (50) from the rear side (X1) to the front side (X2) in the axial direction (X) and reaches the front end (52) of the axial passage (50).

[0072] The refrigerant (W) flows through the axial passage (50) and enters the communication passage (60). The refrigerant (W) flows through the communication passage (60) from the inner circumferential side (R2) to the outer circumferential side (R1) in the radial direction (R). The refrigerant (W) flows out of an opening in the outer circumferential surface (22a) of the rotor (22) and into the gap (A) between the rotor (22) and the stator (23). The high-pressure refrigerant (W) becomes low-pressure as it passes through the communication passage (60) and reaches the gap (A). The low-pressure refrigerant (W) flows through the gap (A) from the rear side (X1) to the front side (X2) in the axial direction (X). The refrigerant (W) enters the discharge passage (25) provided in the outer circumferential wall (24g) of the casing (24). The refrigerant (W) in the discharge passage (25) flows into the evaporator (4).

[0073] As the refrigerant (W) flows through the gap (A) between the rotor (22) and the stator (23) in the axial direction (X), it exchanges heat with the rotor (22) and the stator (23), thereby cooling the rotor (22) and the stator (23) and increasing the temperature of the refrigerant (W) itself.

[0074] The refrigerant (W) is cooled by the condenser (2) before flowing into the refrigerant passage (40). The condenser (2) functions as a cooler. In other words, the electric motor (20) includes the condenser (2) as a cooler that cools the refrigerant (W) before it flows into the refrigerant passage (40).

[0075] Although not shown, the electric motor (20) is provided with an introduction passage for introducing the refrigerant (W) from the outside of the casing (24) into the refrigerant passage (40) in the casing (24).

[0076] In the compressor (10), the refrigerant (W) compressed by the compression mechanism (30) is the same as the refrigerant (W) used to cool the rotor (22) and the stator (23) of the electric motor (20).

[0077] (Effect) The refrigerant (W) is more easily supplied to the gap (A) between the rotor (22) and the stator (23) of the electric motor (20), so that the rotor (22) and the stator (23) of the electric motor (20) can be effectively cooled.

[0078] The refrigerant (W) flows into the axial passage (50) from the rear end surface (21a) of the drive shaft (21) and flows through the axial passage (50) from the rear side (X1) to the front side (X2) in the axial direction (X). The refrigerant (W) can be allowed to flow smoothly into the axial passage (50).

[0079] The refrigerant (W) flows from the axial passage (50) into the communicating passage (60) and flows through the communicating passage (60) from the inner peripheral side (R2) to the outer peripheral side (R1) in the radial direction (R) due to the centrifugal force of the drive shaft (21) and the rotor (22). The refrigerant (W) is supplied from the outer peripheral surface (22a) of the rotor (22) to the gap (A) between the rotor (22) and the stator (23). The refrigerant (W) can be smoothly supplied to the gap (A) between the rotor (22) and the stator (23) of the electric motor (20).

[0080] The first communication passage (60a) is disposed at a distance of ¼L or more from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22). Even in a region far away from the rear shaft end face (21a) of the drive shaft (21) (the inlet opening of the rear end (51) of the axial passage (50)) to the front side (X2) in the axial direction (X), the rotor (22) and the stator (23) can be cooled by the refrigerant (W).

[0081] The communication passages (60) are arranged both behind (X1) and in front (X2) of the center (22m) in the axial direction (X) of the rotor (22). The rotor (22) and the stator (23) can be cooled by the refrigerant (W) in both the area behind (X1) and the area in front (X2) of the center (22m) in the axial direction (X) of the rotor (22).

[0082] The refrigerant (W) before flowing into the refrigerant passage (40) is cooled by the condenser (2) serving as a cooler, which is advantageous in cooling the rotor (22) and the stator (23) with the refrigerant (W).

[0083] The refrigerant (W) compressed by the compressor (10) to a high pressure is introduced into the refrigerant passage (40). The refrigerant (W) is forced into the refrigerant passage (40), and thus the refrigerant (W) easily flows through the refrigerant passage (40).

[0084] Second Embodiment A second embodiment will be described. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 5 is an enlarged cross-sectional view of an electric motor (20) according to the second embodiment.

[0085] The length from the rear rotor end face (22b) on the rear side (X1) to the front rotor end face (22c) on the front side (X2) in the axial direction (X) of the rotor (22) is defined as L.

[0086] The rotor (22) is divided into a first region (C1) consisting of a portion extending from the rear rotor end face (22b) to the front rotor end face (22c) in the axial direction (X) up to 1 / 4L, a second region (C2) consisting of a portion extending from the front rotor end face (22c) to the rear rotor end face (22b) in the axial direction (X) up to 1 / 4L, and a third region (C3) consisting of a portion extending 1 / 2L between the first region (C1) and the second region (C2).

[0087] A first passage volume (V1) per unit length in the axial direction (X) of the communicating passage (60) in the first region (C1) and a second passage volume (V2) per unit length in the axial direction (X) of the communicating passage (60) in the second region (C2) are larger than a third passage volume (V3) per unit length in the axial direction (X) of the communicating passage (60) in the third region (C3).

[0088] The first passage volume (V1) is obtained by dividing the total passage volume of all the communicating passages (60) present in the first region (C1) (the volume of the passages for the refrigerant (W) from the inlets (on the axial passage (50) side) of the communicating passages (60) to the outlets (on the gap (A) side) of the communicating passages (60)) by ¼L, the length in the axial direction (X) of the first region (C1). The second passage volume (V2) is obtained by dividing the total passage volume of all the communicating passages (60) present in the second region (C2) by ¼L, the length in the axial direction (X) of the second region (C2). The third passage volume (V3) is obtained by dividing the total passage volume of all the communicating passages (60) present in the third region (C3) by ½L, the length in the axial direction (X) of the third region (C3).

[0089] Specifically, a first distance (P1) between adjacent communicating passages (60) in the axial direction (X) in the first region (C1) and a second distance (P2) between adjacent communicating passages (60) in the axial direction (X) in the second region (C2) are smaller than a third distance (P3) between adjacent communicating passages (60) in the axial direction (X) in the third region (C3).

[0090] The first interval (P1), the second interval (P2), and the third interval (P3) are, for example, the intervals between the centers of the communicating passages (60) adjacent to each other in the axial direction (X).

[0091] The first average cross-sectional area (S1) of the communicating passage (60) in the first region (C1), the second average cross-sectional area (S2) of the communicating passage (60) in the second region (C2), and the third average cross-sectional area (S3) of the communicating passage (60) in the third region (C3) are all equal to one another.

[0092] The first average cross-sectional area (S1) is obtained by dividing the total cross-sectional area of ​​all the communicating passages (60) present in the first region (C1) by the number of the communicating passages (60) present in the first region (C1). The second average cross-sectional area (S2) is obtained by dividing the total cross-sectional area of ​​all the communicating passages (60) present in the second region (C2) by the number of the communicating passages (60) present in the second region (C2). The third average cross-sectional area (S3) is obtained by dividing the total cross-sectional area of ​​all the communicating passages (60) present in the third region (C3) by the number of the communicating passages (60) present in the third region (C3). Here, the "cross-sectional area" refers to the area of ​​a cross section (so-called transverse section) perpendicular to the flow direction of the refrigerant (W) in the communicating passage (60).

[0093] More specifically, the cross section of the communicating passage (60) is circular, and the diameter of the communicating passage (60) in the first region (C1), the diameter of the communicating passage (60) in the second region (C2), and the diameter of the communicating passage (60) in the third region (C3) are all equal to one another.

[0094] The other configurations are the same as those of the first embodiment.

[0095] By making the first passage volume (V1) and the second passage volume (V2) larger than the third passage volume (V3), the refrigerant (W) can be supplied to the gap (A) between the rotor (22) and the stator (23) more intensively in the first region (C1) and the second region (C2) than in the third region (C3). This is particularly effective when it is desired to cool the rotor (22) and the stator (23) of the electric motor (20) more intensively in the first region (C1) and the second region (C2) than in the third region (C3).

[0096] By making the first interval (P1) and the second interval (P2) smaller than the third interval (P3), the first passage volume (V1) and the second passage volume (V2) can be simply made larger than the third passage volume (V3).

[0097] Third Embodiment A third embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 6 is an enlarged cross-sectional view of an electric motor (20) according to the third embodiment.

[0098] A first passage volume (V1) per unit length in the axial direction (X) of the communicating passage (60) in the first region (C1) and a second passage volume (V2) per unit length in the axial direction (X) of the communicating passage (60) in the second region (C2) are larger than a third passage volume (V3) per unit length in the axial direction (X) of the communicating passage (60) in the third region (C3).

[0099] A first distance (P1) between adjacent communicating passages (60) in the axial direction (X) in the first region (C1), a second distance (P2) between adjacent communicating passages (60) in the axial direction (X) in the second region (C2), and a third distance (P3) between adjacent communicating passages (60) in the axial direction (X) in the third region (C3) are all equal to each other.

[0100] The first average cross-sectional area (S1) of the communicating passage (60) in the first region (C1) and the second average cross-sectional area (S2) of the communicating passage (60) in the second region (C2) are larger than the third average cross-sectional area (S3) of the communicating passage (60) in the third region (C3).

[0101] More specifically, the cross section of the communicating passage (60) is circular, and the diameter of the communicating passage (60) in the first region (C1) and the diameter of the communicating passage (60) in the second region (C2) are larger than the diameter of the communicating passage (60) in the third region (C3).

[0102] The other configurations are the same as those of the second embodiment.

[0103] By making the first passage volume (V1) and the second passage volume (V2) larger than the third passage volume (V3), the refrigerant (W) can be supplied to the gap (A) between the rotor (22) and the stator (23) more intensively in the first region (C1) and the second region (C2) than in the third region (C3). This is particularly effective when it is desired to cool the rotor (22) and the stator (23) of the electric motor (20) more intensively in the first region (C1) and the second region (C2) than in the third region (C3).

[0104] By making the first average cross-sectional area (S1) and the second average cross-sectional area (S2) larger than the third average cross-sectional area (S3), the first passage volume (V1) and the second passage volume (V2) can be made larger than the third passage volume (V3) simply.

[0105] Fourth Embodiment A fourth embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 7 is an enlarged cross-sectional view of an electric motor (20) according to the fourth embodiment.

[0106] The front inner wall of the first communication passage (60a), which is the communication passage (60) that is the farthest from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22), is positioned 1 / 4L away from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22).

[0107] There are a plurality of communication passages (60). The plurality of communication passages (60) are arranged side by side in the axial direction (X). The plurality of communication passages (60) may also be arranged side by side in the circumferential direction around the axis (O) (see FIG. 4 ).

[0108] The communication passage (60) is arranged only in the first region (C1).

[0109] The communication passages (60) are arranged only near the rear rotor end face (22b). This reduces the number of holes to be drilled in the rotor (22) to form the communication passages (60), thereby preventing a reduction in the volume of the magnets and a decrease in the performance of the electric motor (20).

[0110] The other configurations are the same as those of the first embodiment.

[0111] Fifth Embodiment A fifth embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 8 is an enlarged cross-sectional view of an electric motor (20) according to the fifth embodiment.

[0112] There are only two communicating passages (60) in the axial direction. A plurality of communicating passages (60) may be arranged side by side in the circumferential direction around the axis (O) (see FIG. 4 of the first embodiment). The communicating passages (60) are arranged both rearward (X1) and forward (X2) of the center (22m) (½L) in the axial direction (X) of the rotor (22).

[0113] The other configurations are the same as those of the first embodiment.

[0114] Sixth Embodiment A sixth embodiment will now be described. In the following description, the same components as those in the above embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 9 is an enlarged cross-sectional view of an electric motor (20) according to the sixth embodiment.

[0115] The axial passage (50) is tapered. The tapered axial passage (50) decreases in diameter as it extends from the rear side (X1) to the front side (X2) in the axial direction (X). A front end diameter (d2) of the front end (52) of the axial passage (50) is smaller than a rear end diameter (d1) of the rear end (51) of the axial passage (50).

[0116] The other configurations are the same as those of the first embodiment.

[0117] As the refrigerant (W) flows through the axial passage (50) from the rear side (X1) to the front side (X2), the refrigerant (W) can be throttled, which prevents the refrigerant (W) from being difficult to send from the axial passage (50) to the communicating passage (60) due to a decrease in pressure of the refrigerant (W) at the front side (X2) of the axial passage (50).

[0118] Seventh Embodiment A seventh embodiment will be described. In the following description, the same components as those in the above embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 10 shows an enlarged cross-sectional view (taken along line X in Fig. 11) of an electric motor (20) according to the seventh embodiment. Fig. 11 shows a cross-sectional view of the electric motor (20) according to the seventh embodiment as seen in the axial direction (X) (taken along line XI in Fig. 10).

[0119] The axial center (O) of the drive shaft (21) is filled with a wall portion (21c) extending in the axial direction (X). The axial passage (50) is disposed on the outer circumferential side (R1) of the axial center (O) (wall portion (21c)) of the drive shaft (21). The axial passage (50) is configured in an annular shape as seen in the axial direction (X) so as to surround the axial center (O) (wall portion (21c)) of the drive shaft (21).

[0120] The other configurations are the same as those of the first embodiment.

[0121] The axial center (0) of the drive shaft (21) surrounded by the annular shaft passage (50) is formed by the thick portion (21c), thereby ensuring the strength of the drive shaft (21).

[0122] Eighth Embodiment An eighth embodiment will be described. In the following description, the same components as those in the above embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 12 is an enlarged cross-sectional view of an electric motor (20) according to the eighth embodiment, as viewed in the axial direction (X).

[0123] The communicating passage (60) extends, as viewed in the axial direction (X), so as to intersect with a straight line (E) extending from the axial center (O) of the drive shaft (21) to a connection point (B) between the communicating passage (60) and the axial passage (50). An extension line (63) of the communicating passage (60) to the inner circumferential side (R2) does not intersect with the axial center (O) of the drive shaft (21).

[0124] The other configurations are the same as those of the first embodiment.

[0125] By turning the refrigerant (W) flowing through the communication passage (60), not only the centrifugal force of the drive shaft (21) and the rotor (22) but also axial power can be applied to the refrigerant (W) flowing through the communication passage (60). This makes it easier to supply the refrigerant (W) to the gap (A) between the rotor (22) and the stator (23).

[0126] Ninth Embodiment A ninth embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 13 is an enlarged cross-sectional view of an electric motor (20) according to the ninth embodiment.

[0127] The casing (24) includes a discharge passage (25). The discharge passage (25) is a discharge pipe provided in the outer peripheral wall (24g) of the casing (24). The discharge passage (25) extends in the radial direction (R). The discharge passage (25) is disposed on the outer peripheral side (R1) of the outer peripheral surface (22a) of the rotor (22). The discharge passage (25) discharges the refrigerant (W) from the refrigerant passage (40). A pump (26) is provided in the discharge passage (25). The pump (26) promotes the discharge of the refrigerant (W) from the refrigerant passage (40). The pump (26) is, for example, a booster pump.

[0128] The other configurations are the same as those of the first embodiment.

[0129] The pump (26) allows the refrigerant (W) to be smoothly discharged from the refrigerant passage (40) through the discharge passage (25).

[0130] Tenth Embodiment A tenth embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 14 is an enlarged cross-sectional view of an electric motor (20) according to the tenth embodiment.

[0131] There is only one communicating passage (60) in the axial direction. The communicating passage (60) is arranged at only one specific position (G) in the axial direction (X). The specific position (G) is a specific (designated) position in the axial direction (X). The specific position (G) is a specific axial position. There is only one specific position (G). Note that a plurality of communicating passages (60) may be arranged side by side in the circumferential direction around the axis (O) (see FIG. 4 of the first embodiment).

[0132] In this embodiment, the specific position (G) is the center (22m) (½L) in the axial direction (X). The communication passage (60) is disposed at the center (22m) (½L), which is the specific position (G) in the axial direction (X) of the rotor (22). The discharge passage (25) is provided in the outer peripheral wall (24g) of the casing (24). The discharge passage (25) is disposed on the outer peripheral side (R1) of the outer peripheral surface (22a) of the rotor (22).

[0133] There are two discharge passages (25). The two discharge passages (25) are arranged spaced apart from each other in the axial direction (X). The rear (X1) discharge passage (25) is arranged rearward (X1) in the axial direction (X) from the rear rotor end face (22b) of the rotor (22). The front (X2) discharge passage (25) is arranged forward (X2) in the axial direction (X) from the front rotor end face (22c) of the rotor (22).

[0134] The refrigerant (W) flowing out from the outer peripheral surface (22a) of the rotor (22) into the gap (A) is divided into two flows that flow through the gap (A) toward the rear side (X1) and the front side (X2) in the axial direction (X). The refrigerant (W) flows into the rear side (X1) discharge passage (25) and the front side (X2) discharge passage (25) that are provided in the outer peripheral wall (24g) of the casing (24).

[0135] The other configurations are the same as those of the first embodiment.

[0136] The communication passage (60) is disposed at only one specific position (G) in the axial direction (X). Since the number of holes to be drilled in the rotor (22) for forming the communication passage (60) can be reduced, reduction in the volume of the magnet can be suppressed, and deterioration in the performance of the electric motor (20) can be suppressed.

[0137] Eleventh Embodiment An eleventh embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 15 is an enlarged cross-sectional view of an electric motor (20) according to the eleventh embodiment.

[0138] The length from the rear rotor end face (22b) on the rear side (X1) to the front rotor end face (22c) on the front side (X2) in the axial direction (X) of the rotor (22) is defined as L.

[0139] The rotor (22) is divided into a first region (C1) consisting of a portion extending from the rear rotor end face (22b) to the front rotor end face (22c) in the axial direction (X) up to 1 / 4L, a second region (C2) consisting of a portion extending from the front rotor end face (22c) to the rear rotor end face (22b) in the axial direction (X) up to 1 / 4L, and a third region (C3) consisting of a portion extending 1 / 2L between the first region (C1) and the second region (C2).

[0140] The communication passage (60) is arranged only in the first region (C1) in the axial direction (X).

[0141] The communicating passages (60) are preferably arranged in a region from the rear rotor end face (22b) to 1 / 8L of the first region (C1) (1 / 4L from the rear rotor end face (22b)). The communicating passages (60) are preferably arranged in a region from 1 mm to 50 mm from the rear rotor end face (22b), more preferably in a region from 5 mm to 50 mm from the rear rotor end face (22b), and even more preferably in a region from 10 mm to 20 mm from the rear rotor end face (22b).

[0142] There is only one communicating passage (60) in the axial direction (X). The communicating passage (60) is disposed at only one specific position (G) in the axial direction (X). Note that a plurality of communicating passages (60) may be disposed side by side in the circumferential direction around the axis (O) (see FIG. 4 of the first embodiment).

[0143] In this embodiment, the specific position (G) is located in the axial direction (X) within the first region (C1) (1 / 4L from the rear rotor end face (22b)), at a position 1 / 8L away from the rear rotor end face (22b).

[0144] The discharge passage (25) is provided in the outer peripheral wall (24g) of the casing (24). The discharge passage (25) is disposed on the outer peripheral side (R1) of the outer peripheral surface (22a) of the rotor (22). The discharge passage (25) is disposed on the front side (X2) of the front rotor end face (22c).

[0145] The other configurations are the same as those of the first embodiment.

[0146] Since the communication passages (60) are disposed only in the first region (C1), the communication passages (60) are disposed only near the rear rotor end face (22b). This reduces the number of holes to be drilled in the rotor (22) to form the communication passages (60), thereby minimizing the reduction in the volume of the magnets and the deterioration in the performance of the electric motor (20).

[0147] The communication passage (60) is disposed at only one specific position (G) in the axial direction (X). Since the number of holes to be drilled in the rotor (22) for forming the communication passage (60) can be reduced, reduction in the volume of the magnet can be suppressed, and deterioration in the performance of the electric motor (20) can be suppressed.

[0148] The refrigerant (W) that has flowed out from the outer peripheral surface (22a) of the rotor (22) into the gap (A) flows through the gap (A) toward the front side (X2) in the axial direction (X). The refrigerant (W) flows into a discharge passage (25) provided in the outer peripheral wall (24g) of the casing (24) (located forward (X2) of the front rotor end face (22c)).

[0149] By arranging the discharge passage (25) and the communication passage (60) on opposite sides of each other in the axial direction (X), the refrigerant (W) can be more easily supplied to the gap (A) between the rotor (22) and the stator (23).

[0150] <Twelfth Embodiment> A twelfth embodiment will be described. In the following description, the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. Fig. 16 is an enlarged cross-sectional view of an electric motor (20) according to the twelfth embodiment.

[0151] The communication passage (60) is arranged only in the second region (C2) in the axial direction (X).

[0152] The communicating passage (60) is preferably arranged in a region from the front rotor end face (22c) to 1 / 8L of the second region (C2) (1 / 4L from the front rotor end face (22c)). The communicating passage (60) is preferably arranged in a region from 1 mm to 50 mm from the front rotor end face (22c), more preferably in a region from 5 mm to 50 mm from the front rotor end face (22c), and even more preferably in a region from 10 mm to 20 mm from the front rotor end face (22c).

[0153] The communication passage (60) is disposed at only one specific position (G) in the axial direction (X).

[0154] In this embodiment, the specific position (G) is located in the axial direction (X) within the second region (C2) (1 / 4L from the front rotor end face (22c)), at a position 1 / 8L away from the front rotor end face (22c).

[0155] The discharge passage (25) is arranged on the rear side (X1) of the rear rotor end surface (22b).

[0156] The other configurations are the same as those of the eleventh embodiment.

[0157] Since the communication passages (60) are disposed only in the second region (C2), the communication passages (60) are disposed only near the front rotor end face (22c). This reduces the number of holes to be drilled in the rotor (22) to form the communication passages (60), thereby minimizing the reduction in the volume of the magnets and the deterioration in the performance of the electric motor (20).

[0158] The communication passage (60) is disposed at only one specific position (G) in the axial direction (X). Since the number of holes to be drilled in the rotor (22) for forming the communication passage (60) can be reduced, reduction in the volume of the magnet can be suppressed, and deterioration in the performance of the electric motor (20) can be suppressed.

[0159] The refrigerant (W) that has flowed out from the outer peripheral surface (22a) of the rotor (22) into the gap (A) flows through the gap (A) toward the rear side (X1) in the axial direction (X). The refrigerant (W) flows into a discharge passage (25) provided in the outer peripheral wall (24g) of the casing (24) (located rearward (X1) from the rear rotor end face (22b)).

[0160] By arranging the discharge passage (25) and the communication passage (60) on opposite sides of each other in the axial direction (X), the refrigerant (W) can be more easily supplied to the gap (A) between the rotor (22) and the stator (23).

[0161] <Other embodiments> The first communication passage (60a) may be arranged closer to (rearward (X1) than) a position ¼L away from the rear rotor end face (22b) toward the front rotor end face (22c) in the axial direction (X) of the rotor (22).

[0162] Only one of the first passage volume (V1) and the second passage volume (V2) may be larger than the third passage volume (V3). In other words, the first passage volume (V1) or the second passage volume (V2) may be larger than the third passage volume (V3). Only one of the first average cross-sectional area (S1) and the second average cross-sectional area (S2) may be larger than the third average cross-sectional area (S3). In other words, the first average cross-sectional area (S1) or the second average cross-sectional area (S2) may be larger than the third average cross-sectional area (S3). Only one of the first spacing (P1) and the second spacing (P2) may be smaller than the third spacing (P3). In other words, the first spacing (P1) or the second spacing (P2) may be smaller than the third spacing (P3).

[0163] The axial passage (50) may open at the outer peripheral surface (22a) of the rotor (22) near the rear end in the axial direction (X).

[0164] The refrigerant (W) before flowing into the refrigerant passage (40) may be cooled by a cooler separately provided instead of the condenser (2). The cooler may be omitted.

[0165] The cross section of the communication passage (60) is not limited to a circular shape, but may be, for example, a polygonal shape.

[0166] The compressor (10) is not limited to a turbo compressor, but may be, for example, a scroll compressor or a screw compressor.

[0167] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate.

[0168] The terms "first," "second," "third," etc. in the specification and claims are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms.

[0169] X Axial direction X1 Rear side (first direction side) X2 Front side (second direction side) R Radial direction R1 Outer peripheral side R2 Inner peripheral side d Diameter d1 Rear end diameter d2 Front end diameter C1 First region C2 Second region C3 Third region V1 First passage volume V2 Second passage volume V3 Third passage volume P1 First interval P2 Second interval P3 Third interval S1 First average cross-sectional area S2 Second average cross-sectional area S3 Third average cross-sectional area B Connection point E Straight line L Length O Axial center A Gap W Refrigerant W1 High-pressure refrigerant W2 Low-pressure refrigerant G Specific position 1 Refrigeration device 2 Condenser (cooler) 3 Pressure reduction mechanism 4 Evaporator 10 Compressor 20 Electric motor 21 Drive shaft 21a Rear shaft end face (first shaft end face) 21b Front shaft end face 21c Thick portion 21i Inside 22 Rotor 22a Outer peripheral surface 22b Rear rotor end face (first rotor end face) 22c Front rotor end face (second rotor end face) 22m Center 23 Stator 23a Inner peripheral surface 24 Casing 24a Wall portion 24b Impeller chamber 24c Motor chamber 24d Suction pipe 24e Discharge pipe 24f Compression space 24g Outer peripheral wall 25 Discharge passage 26 Pump 27 Touchdown bearing 28 Thrust magnetic bearing 28a Electromagnet 28b Disk portion 30 Compression mechanism 31 Impeller 40 Refrigerant passage 50 Shaft passage 51 Rear end 52 Front end 60 Communication passage 60a First communication passage 61 Outer end 62 Inner end 63 Extension line

Claims

1. A compressor for compressing a refrigerant (W), comprising: an electric motor (20); and a compression mechanism (30) operated by the electric motor (20), wherein the compression mechanism (30) comprises an impeller (31) rotated by the electric motor (20), wherein the electric motor (20) comprises: a drive shaft (21); a rotor (22) fixed to the drive shaft (21); and a stator (23) arranged on an outer circumferential side (R1) of the rotor (22), wherein the drive shaft (21) and the rotor (22) comprise a refrigerant passage (40) through which the refrigerant (W) flows, wherein the refrigerant passage (40) comprises: an axial passage (50) extending through an interior (21i) of the drive shaft (21) from a first direction side (X1) in an axial direction (X) to a second direction side (X2) opposite to the first direction side (X1) and on which the impeller (31) is arranged; The compressor further comprises a communication passage (60) that connects a gap (A) between the rotor (22) and the stator (23) with the axial passage (50).

2. The compressor according to claim 1, wherein the axial passage (50) opens to a first axial end surface (21a) of the drive shaft (21) on the first direction side (X1) in the axial direction (X) of the drive shaft (21).

3. The compressor according to claim 1 or 2, wherein the communication passage (60) opens onto the outer peripheral surface (22a) of the rotor (22).

4. When the length from the first rotor end face (22b) on the first direction side (X1) to the second rotor end face (22c) on the second direction side (X2) in the axial direction (X) of the rotor (22) is defined as L, and the rotor (22) is divided into a first region (C1) consisting of a portion from the first rotor end face (22b) to the second rotor end face (22c) in the axial direction (X) up to 1 / 4L, a second region (C2) consisting of a portion from the second rotor end face (22c) to the first rotor end face (22b) in the axial direction (X) up to 1 / 4L, and a third region (C3) consisting of a portion of 1 / 2L between the first region (C1) and the second region (C2), 4. The compressor according to claim 1, wherein a first passage volume (V1) per unit length in the axial direction (X) of the communicating passage (60) in the first region (C1) or a second passage volume (V2) per unit length in the axial direction (X) of the communicating passage (60) in the second region (C2) is larger than a third passage volume (V3) per unit length in the axial direction (X) of the communicating passage (60) in the third region (C3).

5. A compressor according to claim 4, wherein a first average cross-sectional area (S1) of the communicating passage (60) in the first region (C1) or a second average cross-sectional area (S2) of the communicating passage (60) in the second region (C2) is larger than a third average cross-sectional area (S3) of the communicating passage (60) in the third region (C3).

6. The compressor according to claim 4, wherein a first interval (P1) between the communicating passages (60) adjacent to each other in the axial direction (X) in the first region (C1) or a second interval (P2) between the communicating passages (60) adjacent to each other in the axial direction (X) in the second region (C2) is smaller than a third interval (P3) between the communicating passages (60) adjacent to each other in the axial direction (X) in the third region (C3).

7. The compressor according to any one of claims 2 to 6, wherein, when a length from a first rotor end face (22b) on the first direction side (X1) in the axial direction (X) of the rotor (22) to a second rotor end face (22c) on the second direction side (X2) is defined as L, the communicating passage (60) that is furthest from the first rotor end face (22b) toward the second rotor end face (22c) in the axial direction (X) of the rotor (22) is arranged at a distance of ¼L or more from the first rotor end face (22b) toward the second rotor end face (22c) in the axial direction (X) of the rotor (22).

8. A compressor as described in any one of claims 1 to 7, wherein the communication passage (60) is arranged on both the first direction side (X1) and the second direction side (X2) of the center (22m) in the axial direction (X) of the rotor (22).

9. A compressor as described in any one of claims 1 to 8, wherein the communicating passage (60) extends, as viewed in the axial direction (X), so as to intersect with a straight line (E) extending from the axial center (O) of the drive shaft (21) to a connection point (B) between the communicating passage (60) and the axial passage (50).

10. A compressor according to any one of claims 1 to 9, wherein the axial passage (50) is configured annularly so as to surround the axial center (O) of the drive shaft (21) when viewed in the axial direction (X).

11. A compressor according to any one of claims 1 to 10, wherein the axial passage (50) is formed in a tapered shape such that its diameter decreases as it extends from the first direction side (X1) to the second direction side (X2) in the axial direction.

12. A compressor as described in any one of claims 1 to 11, wherein the electric motor (20) comprises a casing (24) that houses the drive shaft (21), the rotor (22), and the stator (23), the casing (24) includes a discharge passage (25) that discharges the refrigerant (W) from the refrigerant passage (40), and the discharge passage (25) is provided with a pump (26) that promotes the discharge of the refrigerant (W).

13. A compressor according to any one of claims 1 to 12, further comprising a cooler (2) that cools the refrigerant (W) before it flows into the refrigerant passage (40).

14. A compressor according to any one of claims 1 to 13, wherein the communication passage (60) is disposed at only one specific position (G) in the axial direction (X).

15. The compressor according to any one of claims 1 to 14, wherein when a length from a first rotor end face (22b) on the first direction side (X1) to a second rotor end face (22c) on the second direction side (X2) in the axial direction (X) of the rotor (22) is defined as L, and the rotor (22) is divided into a first region (C1) consisting of a portion extending from the first rotor end face (22b) to the second rotor end face (22c) in the axial direction (X) up to 1 / 4L, a second region (C2) consisting of a portion extending from the second rotor end face (22c) to the first rotor end face (22b) in the axial direction (X) up to 1 / 4L, and a third region (C3) consisting of a portion extending 1 / 2L between the first region (C1) and the second region (C2), the communicating passage (60) is arranged only in the first region (C1) or only in the second region (C2).

16. A refrigeration system including a compressor (10) according to any one of claims 1 to 15.

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