Rotors, motors, compressors, refrigeration equipment

Abstract

This relieves the stress acting on the rotor core as the rotor rotates. [Solution] In a cross section perpendicular to the axis of rotation (Q), the fastening member (45) for fastening the rotor core (20) is positioned in the first hole (35). The second void (32) is positioned radially inward from the first void (31). The radially outer wall surface of the second void (32) is formed to be convex with respect to the axis of rotation (Q). The first hole (35) is positioned between the first void (31) and the second void (32).

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an electric motor having a stator and a rotor. In the holes formed between the rotating shaft and the magnet accommodating holes in the rotor core, refrigerant and refrigeration oil flow.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric motor such as Patent Document 1, it is conceivable to provide a hole (for example, a bolt hole) for arranging a fastening member used for fastening the rotor between the rotating shaft and the magnet accommodating hole. However, in such a configuration, when a centrifugal force acts on the magnet accommodated in the magnet accommodating hole due to the rotation of the rotor, a stress corresponding to the centrifugal force acts on the rotor core (a portion radially outside the magnet accommodating hole), so it is difficult to relieve the stress acting on the rotor core.

Means for Solving the Problems

[0005] A first aspect of the present disclosure relates to a rotor rotatable about a rotation axis (Q), the rotor including a rotor core (20) in which a first gap portion (31), a second gap portion (32), and a first hole (35) are formed for each magnetic pole, a first magnet (41) provided for each magnetic pole, a second magnet (42) provided for each magnetic pole, and a fastening member (45) for fastening the rotor core (20). In a cross-section perpendicular to the rotation axis (Q), The first magnet (41) is placed in the first gap (31), The second magnet (42) is placed in the second gap (32), The fastening member (45) is positioned in the first hole (35), The second void (32) is located radially inward from the first void (31), The radially outer wall surface of the second gap (32) is formed to be convex with respect to the rotation axis (Q), The first hole (35) is located between the first void (31) and the second void (32).

[0006] In the first embodiment, by positioning the first hole (35) in which the fastening member (45) is placed radially outward from the second gap (32) in which the second magnet (42) is placed, the centrifugal force acting on the second magnet (42) in accordance with the rotation of the rotor (11) can be absorbed by the fastening member (45). This makes it possible to alleviate the stress acting on the rotor core (20) in accordance with the rotation of the rotor (11).

[0007] A second aspect of this disclosure relates to the rotor of the first aspect, In the cross-section, the radially outer wall surface of the second void (32) is formed in an arc shape that is convex with respect to the axis of rotation (Q), In the aforementioned cross-section, if the distance between the circumferential end of the first void (31) and the circumferential end of the second void (32) is defined as the first distance (D1), and if a first straight line (L1) is hypothetically drawn as a straight line passing through the center of curvature (Q1) of the radially outer wall surface of the second void (32) closest to the first hole (35) and the center (Q2) of the first hole (35), then the distance between the wall surface of the first void (31) and the wall surface of the second void (32) on this first straight line (L1) is defined as the distance corresponding to the length of the first hole (35) on this first straight line (L1), then the first distance (D1) is shorter than the distance obtained by subtracting the third distance (D3) from the second distance (D2). It is a rotor.

[0008] In the second embodiment, the flow of magnetic flux in the magnetic path section (22) located between the first gap (31) and the second gap (32) can be ensured, thereby suppressing the reduction in torque due to the arrangement (drilling) of the first hole (35).

[0009] A third aspect of this disclosure relates to the rotor of the first or second aspect, The rotor core (20) has a second hole (30) formed therein. In the cross-section, The second hole (30) is located in the central part of the rotor core (20), The radially inner wall surface of the second void (32) is formed to be convex with respect to the rotation axis (Q), In the aforementioned cross-section, if the distance between the circumferential ends of two adjacent second void portions (32) in the circumferential direction, and the shortest distance between the wall surface of the second void portion (32) and the wall surface of the second hole (30) is defined as the fourth distance (D4), then half of the fourth distance (D4) is shorter than the fifth distance (D5). It is a rotor.

[0010] In the third embodiment, the flow of magnetic flux between the second air gap (32) and the second hole (30) can be ensured. This prevents a deficiency of magnetic flux between the second air gap (32) and the second hole (30), thereby suppressing a decrease in torque due to insufficient magnetic flux.

[0011] A fourth aspect of this disclosure relates to a rotor in any one of the first to third aspects, The second void (32) is composed of a single void that extends continuously from one end to the other in the circumferential direction of the second void (32) in the cross-section. It is a rotor.

[0012] In the fourth aspect, the reluctance torque can be increased as compared with the case where the second void portion (32) is not continuous from one circumferential end to the other end.

[0013] A fifth aspect of the present disclosure is in a rotor according to any one of the first to fourth aspects, in the cross section, the shortest distance between the wall surface of the first hole (35) and the wall surface of the first void portion (31) is shorter than the shortest distance between the wall surface of the first hole (35) and the wall surface of the second void portion (32). is a rotor.

[0014] In the fifth aspect, the first hole (35) can be brought closer to the first void portion (31). As a result, the first hole (35) in which the fastening member (45) is disposed can be disposed closer to the outer diameter side. Therefore, the stress acting on the rotor core (20) in accordance with the rotation of the rotor (11) can be relieved more than in the case where the first hole (35) is disposed closer to the inner diameter side.

[0015] A sixth aspect of the present disclosure relates to a motor including a rotor according to any one of the first to fifth aspects.

[0016] A seventh aspect of the present disclosure relates to a compressor including the motor of the sixth aspect.

[0017] An eighth aspect of the present disclosure relates to a refrigeration device including the motor of the sixth aspect.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a cross-sectional view illustrating the overall configuration of the motor of the embodiment. [Figure 2] FIG. 2 is a cross-sectional view illustrating the configuration of the motor of the embodiment. [Figure 3] FIG. 3 is a cross-sectional view illustrating the configuration of the main part of the rotor of the embodiment. [Figure 4] FIG. 4 is a graph illustrating the relationship between the third distance and the torque. [Figure 5]Figure 5 is a longitudinal cross-sectional view illustrating the configuration of a compressor. [Figure 6] Figure 6 is a piping diagram illustrating the configuration of a refrigeration system. [Modes for carrying out the invention]

[0019] The embodiments will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, this disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of ​​this disclosure. Since the drawings are for conceptual explanation of this disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding. The fastening member (45) fastens the rotor core (20).

[0020] (Embodiment) Figures 1 and 2 illustrate the configuration of the motor (10) of the embodiment. The motor (10) comprises a rotor (11) that can rotate about a rotation axis (Q) and a stator (12). The rotor (11) is fixed to a shaft (15).

[0021] In the following explanation, the direction of the axis of rotation (Q) will be referred to as the "axial direction." The direction perpendicular to the axis of rotation (Q) will be referred to as the "radial direction." The direction around the axis of rotation (Q) will be referred to as the "circumferential direction." Furthermore, a cross-section along the axial direction will be referred to as the "longitudinal section." A cross-section perpendicular to the axial direction will be referred to as the "transverse section."

[0022] [Status] The stator (12) is positioned radially outward from the rotor (11). In this example, the stator (12) faces the rotor (11) with a predetermined gap between them. The stator (12) has a stator core (50) and N-phase (N is an integer of 3 or more) coils (61) formed by conductors (60).

[0023] The stator core (50) has a cylindrical yoke (51) and a plurality of teeth (52) arranged circumferentially on the radially inner side of the yoke (51). Each of the plurality of teeth (52) extends radially inward from the inner circumferential surface of the yoke (51). Slots for housing N-phase coils (61) are formed between the plurality of teeth (52).

[0024] The N-phase coil (61) consists of a conductor (60) wound around multiple teeth (52).

[0025] In the following explanation, a winding method of the conductor (60) where the number of slots per pole per phase is "1" or less will be described as "concentrated winding," and a winding method of the conductor (60) where the number of slots per pole per phase is greater than "1" will be described as "distributed winding." The number of slots per pole per phase is obtained by dividing the number of slots formed in the stator core (50) by the product of the "number of phases of the coil (61)" and the "number of poles of the rotor (11)."

[0026] In this example, the N-phase coil (61) is composed of a conductor (60) wound around each of the multiple teeth (52). Specifically, the conductor (60) is wound around the teeth (52) by concentrated winding. Alternatively, the conductor (60) may be wound around the teeth (52) by distributed winding.

[0027] [Rotor] The rotor (11) has a rotor core (20). The rotor (11) also has a first magnet (41), a second magnet (42), and a fastening member (45) for each magnetic pole. In this example, the rotor (11) has 6 magnetic poles, with 6 first magnets (41) arranged at equal intervals in the circumferential direction and 6 second magnets (42) arranged at equal intervals in the circumferential direction.

[0028] <Rotor Core> The rotor core (20) is made of a soft magnetic material. Furthermore, the rotor core (20) is composed of a laminated core. Specifically, the rotor core (20) is constructed by laminating multiple disc-shaped members, each made of electromagnetic steel sheet, in the axial direction. The cross-sectional shape of the rotor core (20) is identical along its entire axial length. In this example, the outer cross-sectional shape of the rotor core (20) is circular.

[0029] Furthermore, in this example, among the components of the rotor core (20), the "components provided for each magnetic pole of the rotor (11) (for example, the first air gap (31) described later)" are formed symmetrically with respect to a line axis extending radially from the rotation axis (Q) in a cross section perpendicular to the rotation axis (Q). In other words, a line axis of symmetry (imaginary line) is provided for each magnetic pole of the rotor (11), and the components included in that magnetic pole are formed symmetrically with respect to that line axis of symmetry.

[0030] <Axial hole> A shaft hole (30) is formed in the rotor core (20). The shaft hole (30) is located in the center of the rotor core (20) and penetrates the rotor core (20) in the axial direction. The cross-sectional shape of the shaft hole (30) is circular with respect to the axis of rotation (Q), and is the same along the entire axial length of the rotor core (20). The wall surface of the shaft hole (30) is cylindrical with respect to the axis of rotation (Q). A shaft (15) is inserted into and fixed in the shaft hole (30).

[0031] <Void area> The rotor core (20) has a first void (31), a second void (32), and a first hole (35) formed for each magnetic pole of the rotor (11). In this example, six first voids (31) are arranged at equal intervals in the circumferential direction, six second voids (32) are arranged at equal intervals in the circumferential direction, and six first holes (35) are arranged at equal intervals in the circumferential direction. The second voids (32) are located radially outward from the shaft hole (30). The first voids (31) are located radially outward from the second voids (32).

[0032] The first void (31) is formed such that its radially outer side is closed and the radially outer wall surface of the first void (31) is convex radially outward. Specifically, the radially outer wall surface of the first void (31) is formed in the shape of an arc convex radially outward. The central surface of the radially inner wall surface of the first void (31) in the circumferential direction is formed in a planar shape perpendicular to the axis of symmetry described above. The end face surfaces of the radially inner wall surface of the first void (31) in the circumferential direction (faces adjacent to the central surface in the circumferential direction) are formed in a planar shape that is inclined with respect to the central surface and is aligned radially.

[0033] Furthermore, the first void (31) is located closer to the outer surface of the rotor core (20) rather than closer to the shaft hole (30). In other words, the shortest distance between the first void (31) and the axis of rotation (Q) is longer than half the shortest distance between the outer surface of the rotor core (20) and the axis of rotation (Q).

[0034] The second void (32) is formed to be convex toward the axis of rotation (Q). The radially outer and radially inner walls of the second void (32) are formed in the shape of an arc convex toward the axis of rotation (Q). In this example, the second void (32) is composed of a single void that is continuous from one end to the other in the circumferential direction of the second void (32) in a cross section perpendicular to the axis of rotation (Q).

[0035] <1st hole> The first hole (35) is located between the first gap (31) and the second gap (32). In this example, the first hole (35) is located in the central part of the circumferential direction of the portion between the first gap (31) and the second gap (32) (the magnetic path portion (22) described later). The cross-sectional shape of the first hole (35) is circular. A fastening member (45) is inserted into the first hole (35). The fastening of the rotor (11) using the first hole (35) and the fastening member (45) will be described in detail later.

[0036] <Rotor core configuration> The rotor core (20) has a base (21). The rotor core (20) also has a magnetic path section (22), an arc section (23), a first bridge (24), and a second bridge (25) for each magnetic pole of the rotor (11).

[0037] <base> The base portion (21) is the part between the shaft hole (30) and the multiple second gap portions (32). The radially outer wall surface of the base portion (21) has a surface portion that is convex toward the rotation axis (Q) for each magnetic pole of the rotor (11). The surface portion is formed in the shape of an arc convex toward the rotation axis (Q). The radially inner wall surface of the base portion (21) constitutes the wall surface of the shaft hole (30). In addition, protrusions are formed between adjacent surface portions in the circumferential direction, projecting radially outward.

[0038] <Magnetic circuit section> The magnetic path portion (22) is the portion between the first gap portion (31) and the second gap portion (32). The first gap portion (31) is formed radially outward from the magnetic path portion (22). The second gap portion (32) is positioned radially inward from the magnetic path portion (22).

[0039] The magnetic path section (22) is formed to be convex toward the axis of rotation (Q). The central surface of the radially outer wall of the magnetic path section (22) in the circumferential direction is formed as a plane perpendicular to the axis of symmetry. The end face portions of the radially outer wall of the magnetic path section (22) in the circumferential direction (faces adjacent to the central surface in the circumferential direction) are formed as a plane inclined with respect to the central surface and aligned with the radial direction. The radially inner wall of the magnetic path section (22) is formed as an arc-shaped surface that is convex toward the axis of rotation (Q).

[0040] <Arc section> The arc portion (23) is provided radially outward from the first gap portion (31) and closes the radially outward side of the first gap portion (31). Specifically, the radially outward wall surface of the arc portion (23) is a surface portion that constitutes a part of the outer circumferential surface of the rotor core (20) and is formed in the shape of an arc with respect to the rotation axis (Q). The radially inward wall surface of the arc portion (23) is formed in the shape of an arc with respect to the rotation axis (Q).

[0041] <bridge> The first bridge (24) connects the surface portion on one end of the magnetic path portion (22) in the circumferential direction to the protruding portion of the base portion (21), and closes the circumferential end of the second gap portion (32). The radially outer wall surface of the first bridge (24) is a surface portion that constitutes a part of the outer circumferential surface of the rotor core (20), and is formed in the shape of an arc with respect to the rotation axis (Q).

[0042] The second bridge (25) connects the surface portion on the other end side in the circumferential direction of the magnetic path portion (22) to the protruding portion of the base portion (21), and closes the other end side in the circumferential direction of the second gap portion (32). The radially outer wall surface of the second bridge (25) is a surface portion that constitutes a part of the outer circumferential surface of the rotor core (20), and is formed in the shape of an arc with respect to the rotation axis (Q).

[0043] 〔magnet〕 The first magnet (41) is placed in the first void (31). The cross-sectional shape of the first magnet (41) corresponds to the cross-sectional shape of the first void (31). The radially outer wall surface of the first magnet (41) is formed in the shape of an arc convex radially outward. The central surface of the radially inner wall surface of the first magnet (41) in the circumferential direction is formed in the shape of a plane perpendicular to the axis of symmetry described above. The end face surfaces of the radially inner wall surface of the first magnet (41) in the circumferential direction (faces adjacent to the central surface in the circumferential direction) are formed in the shape of a plane that is inclined with respect to the central surface and is aligned radially. For example, the first magnet (41) is a sintered magnet.

[0044] The second magnet (42) is placed in the second void (32). The cross-sectional shape of the second magnet (42) corresponds to the cross-sectional shape of the second void (32). The radially outer and radially inner walls of the second magnet (42) are formed in the shape of an arc that is convex toward the axis of rotation (Q). For example, the second magnet (42) is a sintered magnet.

[0045] [Fastening components] The fastening member (45) is a rod-shaped member and is used to fasten the rotor (11). The fastening member (45) fastens the rotor (11) when inserted into the first hole (35). For example, the fastening member (45) is a bolt, and the first hole (35) is a bolt hole. End plates (not shown) are placed on both axial ends of the rotor core (20), and with the first hole (35) formed in the rotor core (20) and the end plate holes (holes corresponding to the first hole (35)) formed in the end plates in communication, the bolt, which is the fastening member (45), is inserted into the first hole (35) and the end plate holes, and a nut (not shown) is tightened onto the bolt. This fastens the rotor (11). The material constituting the fastening member (45) may be a soft magnetic material such as iron, or a non-magnetic material such as stainless steel, resin, or brass.

[0046] [Detailed structure of the rotor core] Next, the detailed structure of the rotor (11) will be described with reference to Figure 3.

[0047] In the following explanation, the distance between the circumferential end of the first void (31) and the circumferential end of the second void (32) will be referred to as the "first distance (D1)". The first distance (D1) corresponds to the width of the circumferential end of the magnetic path section (22), and also corresponds to the distance between the arc section (23) and the first bridge (24) (or the second bridge (25)). If the distance between one circumferential end of the first void (31) and one circumferential end of the second void (32) is different from the distance between the other circumferential end of the first void (31) and the other circumferential end of the second void (32), the shorter of these two distances will be referred to as the first distance (D1).

[0048] Furthermore, the distance between the wall surface of the first void (31) and the wall surface of the second void (32) on a hypothetical first straight line (L1) that passes through the center of curvature (Q1) of the radially outer wall surface of the second void (32) closest to the first hole (35) and the center (Q2) of the first hole (35) is defined as the "second distance (D2)". The intersection point of the first straight line (L1) with the radially inner wall surface of the first void (31) is defined as the "first intersection point (Q3)", and the intersection point of the first straight line (L1) with the radially outer wall surface of the second void (32) is defined as the "second intersection point (Q4)", then the second distance (D2) corresponds to the distance between the first intersection point (Q3) and the second intersection point (Q4).

[0049] Furthermore, the distance corresponding to the length of the first hole (35) on the first straight line (L1) is defined as the "third distance (D3)". In this example, the cross-sectional shape of the first hole (35) is circular, and the third distance (D3) corresponds to the diameter of the first hole (35).

[0050] Furthermore, the distance between the circumferential ends of two adjacent second gaps (32) in the circumferential direction, among the second gaps (32) provided for each magnetic pole of the rotor (11), is defined as the "fourth distance (D4)". The fourth distance (D4) corresponds to the width of the protruding end of the protruding part of the base (21), and also corresponds to the distance between adjacent first bridges (24) and second bridges (25) in the circumferential direction.

[0051] Furthermore, the shortest distance between the wall surface of the second void (32) and the wall surface of the axial hole (30) is defined as the "fifth distance (D5)". The fifth distance (D5) corresponds to the minimum value of the thickness (length in the radial direction) of the base (21).

[0052] As shown in Figure 3, in a cross section perpendicular to the axis of rotation (Q), the first magnet (41) is positioned in the first gap (31). The second magnet (42) is positioned in the second gap (32). The fastening member (45) is positioned in the first hole (35). The second gap (32) is positioned radially inward from the first gap (31). The radially outer wall surface of the second gap (32) is formed to be convex with respect to the axis of rotation (Q). The first hole (35) is positioned between the first gap (31) and the second gap (32).

[0053] Furthermore, as shown in Figure 3, the radially outer wall surface of the second gap (32) is formed in an arc shape that is convex with respect to the axis of rotation (Q). The components of the rotor core (20) are designed such that the first distance (D1) is shorter than the distance obtained by subtracting the third distance (D3) from the second distance (D2). For example, the first distance (D1) and the second distance (D2) are determined based on the design of the magnetic properties of the rotor (11) (what kind of magnetic properties to have), and the third distance (D3) is determined such that the above relationship holds true.

[0054] Furthermore, as shown in Figure 3, the shaft hole (30) is located in the center of the rotor core (20). The radially inner wall surface of the second gap (32) is formed to be convex with respect to the axis of rotation (Q). The components of the rotor core (20) are designed such that half of the fourth distance (D4) is shorter than the fifth distance (D5). For example, the fourth distance (D4) is determined based on the design of the magnetic properties of the rotor (11) (what kind of magnetic properties to have), and the fifth distance (D5) is determined so that the above relationship holds. The fifth distance (D5) may also be shorter than the second distance (D2).

[0055] [Relationship between third distance (D3) and torque] Next, referring to Figure 4, we will explain the relationship between the third distance (D3) and the torque of the motor (10). Here, we assume that the first distance (D1) is "1.6 mm" and the second distance (D2) is "6.85 mm".

[0056] When the third distance (D3) is "4.00 mm", the first distance (D1) (1.6 mm) is shorter than the distance obtained by subtracting the third distance (D3) from the second distance (D2) (6.85 mm - 4.00 mm = 2.85 mm). In this case, the torque of the motor (10) is equivalent to the torque when the third distance (D3) is zero (when the first hole (35) is not provided). Under these conditions, the flow of magnetic flux in the magnetic path section (22) located between the first gap section (31) and the second gap section (32) is ensured, and it can be said that the reduction in torque due to the arrangement (drilling) of the first hole (35) is suppressed.

[0057] Furthermore, when the third distance (D3) is "6.00 mm", the first distance (D1) (1.6 mm) is longer than the distance obtained by subtracting the third distance (D3) from the second distance (D2) (6.85 mm - 6.00 mm = 2.85 mm). In this case, the torque of the motor (10) is significantly lower than the torque when the third distance (D3) is zero (when the first hole (35) is not provided). Under these conditions, the flow of magnetic flux in the magnetic path section (22) is not ensured, and the reduction in torque due to the arrangement (drilling) of the first hole (35) is not suppressed.

[0058] [Effects of the Embodiment] As described above, in the motor (10) of the embodiment, the fastening member (45) is positioned in the first hole (35) in a cross section perpendicular to the axis of rotation (Q). The second gap (32) is positioned radially inward from the first gap (31). The radially outer wall surface of the second gap (32) is formed to be convex with respect to the axis of rotation (Q). The first hole (35) is positioned between the first gap (31) and the second gap (32).

[0059] In the above configuration, by positioning the first hole (35) in which the fastening member (45) is placed radially outward from the second gap (32) in which the second magnet (42) is placed, the centrifugal force acting on the second magnet (42) in accordance with the rotation of the rotor (11) can be absorbed by the fastening member (45). This makes it possible to alleviate the stress acting on the rotor core (20) in accordance with the rotation of the rotor (11).

[0060] Specifically, stress concentration in the first bridge (24) and the second bridge (25) of the rotor core (20) can be alleviated. As a result, the thickness (radial length) of the first bridge (24) and the second bridge (25) can be reduced, thereby improving the efficiency of the motor (10).

[0061] Furthermore, in the above configuration, since the first hole (35) is not provided radially inward of the second gap (32), the diameter of the shaft hole (30) can be increased. This makes it possible to increase the diameter of the shaft (15) inserted into the shaft hole (30).

[0062] Furthermore, in the motor (10) of the embodiment, in a cross-section perpendicular to the axis of rotation (Q), the radially outer wall surface of the second gap (32) is formed in an arc shape that is convex with respect to the axis of rotation (Q). If we define the distance between the circumferential end of the first void (31) and the circumferential end of the second void (32) as the first distance (D1), and define the distance between the wall surface of the first void (31) and the wall surface of the second void (32) on a hypothetical straight line (L1) passing through the center of curvature (Q1) of the radially outer wall surface of the second void (32) closest to the first hole (35) and the center (Q2) of the first hole (35), then define the distance between the wall surface of the first void (31) and the wall surface of the second void (32) on the first straight line (L1) as the distance corresponding to the length of the first hole (35) on the first straight line (L1), then the first distance (D1) is shorter than the distance obtained by subtracting the third distance (D3) from the second distance (D2).

[0063] In the above configuration, the flow of magnetic flux in the magnetic path section (22) located between the first gap section (31) and the second gap section (32) can be ensured, thereby suppressing the reduction in torque caused by the arrangement (drilling) of the first hole (35).

[0064] Furthermore, in the motor (10) of the embodiment, a shaft hole (30) (second hole) is formed in the rotor core (20). In a cross section perpendicular to the axis of rotation (Q), the shaft hole (30) is located in the center of the rotor core (20). The radially inner wall surface of the second gap (32) is formed to be convex with respect to the axis of rotation (Q). In a cross section perpendicular to the axis of rotation (Q), if the distance between the circumferential ends of two adjacent second gaps (32) in the circumferential direction, and the shortest distance between the wall surface of the second gap (32) and the wall surface of the shaft hole (30) is defined as the fourth distance (D4), then half of the fourth distance (D4) is shorter than the fifth distance (D5).

[0065] In the above configuration, the flow of magnetic flux between the second air gap (32) and the shaft hole (30) can be ensured. This prevents a deficiency of magnetic flux between the second air gap (32) and the shaft hole (30), thereby suppressing a decrease in torque due to insufficient magnetic flux.

[0066] Furthermore, in the motor (10) of the embodiment, the second gap (32) is composed of a single gap that extends from one end to the other in the circumferential direction of the second gap (32) in cross-section along the axis of rotation (Q).

[0067] In the above configuration, the reluctance torque can be increased compared to the case where the second gap (32) is not continuous from one end to the other in the circumferential direction.

[0068] (Modified examples of the embodiment) In the modified motor (10) of the embodiment, the shortest distance between the wall surface of the first hole (35) and the wall surface of the first gap (31) in a cross section perpendicular to the axis of rotation (Q) is shorter than the shortest distance between the wall surface of the first hole (35) and the wall surface of the second gap (32). The other configurations of the modified motor (10) of the embodiment are the same as those of the motor (10) of the embodiment.

[0069] In the above configuration, the first hole (35) can be brought closer to the first gap (31). As a result, the first hole (35) where the fastening member (45) is placed can be positioned more radially outward, which reduces the stress acting on the rotor core (20) in response to the rotation of the rotor (11) compared to when the first hole (35) is positioned more radially inward.

[0070] (Compressor) Figure 5 illustrates the configuration of a compressor (CC). The compressor (CC) comprises a motor (10), a casing (CC1), and a compression mechanism (CC2).

[0071] The casing (CC1) houses the compression mechanism (CC2) and the motor (10). In this example, the casing (CC1) is formed in a cylindrical shape that extends vertically and is closed at both ends. The casing (CC1) is provided with an intake pipe (CC11) and a discharge pipe (CC12). The intake pipe (CC11) passes through the body of the casing (CC1) and is connected to the compression mechanism (CC2). The discharge pipe (CC12) passes through the top of the casing (CC1) and communicates with the internal space of the casing (CC1).

[0072] The compression mechanism (CC2) compresses the fluid. In this example, the compression mechanism (CC2) is located below the motor (10). The compression mechanism (CC2) compresses the fluid drawn in through the intake pipe (CC11) and discharges the compressed fluid into the internal space of the casing (CC1). The fluid discharged into the internal space of the casing (CC1) is then discharged through the discharge pipe (CC12).

[0073] The shaft (15) connects the motor (10) and the compression mechanism (CC2). In this example, the shaft (15) extends vertically. The motor (10) rotates the shaft (15). The rotational drive of the shaft (15) drives the compression mechanism (CC2).

[0074] Note that the drive method for the compressor (CC) is not limited to the drive method shown in Figure 5. For example, the compressor (CC) may be a scroll type, screw type, turbo type, or other type of compressor.

[0075] (Refrigeration equipment) Figure 6 illustrates the configuration of a refrigeration system (RR). The refrigeration system (RR) comprises a refrigerant circuit (RR1) through which the refrigerant circulates, a first blower (RR5a), and a second blower (RR6a). The refrigerant circuit (RR1) includes a compressor (CC) with a motor (10), a first heat exchanger (RR5), a second heat exchanger (RR6), an expansion mechanism (RR7), and a four-way switching valve (RR8). In this example, the expansion mechanism (RR7) is an electronic expansion valve. The refrigerant circuit (RR1) performs a vapor compression type refrigeration cycle. For example, the first heat exchanger (RR5) is a heat source heat exchanger and is located outside the room. The second heat exchanger (RR6) is a utilization heat exchanger and is located inside the room. The first blower (RR5a) transports air to the first heat exchanger (RR5). The second blower (RR6a) delivers air to the second heat exchanger (RR6).

[0076] The discharge side of the compressor (CC) is connected to the first port (P1) of the four-way directional control valve (RR8). The suction side of the compressor (CC) is connected to the second port (P2) of the four-way directional control valve (RR8). The gas end of the first heat exchanger (RR5) is connected to the third port (P3) of the four-way directional control valve (RR8). The liquid end of the first heat exchanger (RR5) is connected to the liquid end of the second heat exchanger (RR6) via the expansion mechanism (RR7). The gas end of the second heat exchanger (RR6) is connected to the fourth port (P4) of the four-way directional control valve (RR8).

[0077] The four-way switching valve (RR8) can be switched between a first state (shown by the solid line in Figure 6) in which the first port (P1) and the third port (P3) are in communication and the second port (P2) and the fourth port (P4) are in communication, and a second state (shown by the dashed line in Figure 6) in which the first port (P1) and the fourth port (P4) are in communication and the second port (P2) and the third port (P3) are in communication.

[0078] When the four-way switching valve (RR8) is in the first state, the refrigerant discharged from the compressor (CC) dissipates heat in the first heat exchanger (RR5), is depressurized in the expansion mechanism (RR7), and then absorbs heat in the second heat exchanger (RR6). The refrigerant flowing out of the second heat exchanger (RR6) is drawn into the compressor (CC).

[0079] When the four-way switching valve (RR8) is in the second state, the refrigerant discharged from the compressor (CC) dissipates heat in the second heat exchanger (RR6), is depressurized in the expansion mechanism (RR7), and then absorbs heat in the first heat exchanger (RR5). The refrigerant flowing out of the first heat exchanger (RR5) is drawn into the compressor (CC).

[0080] For example, the refrigeration unit (RR) is an air conditioner that switches between cooling and heating. The refrigeration unit (RR) may be a cooling-only unit or a heating-only unit. In this case, the four-way switching valve (RR8) may be omitted from the refrigeration unit (RR). Furthermore, the refrigeration unit (RR) may be a water heater, chiller unit, or cooling device that cools the air inside a storage unit. The cooling device cools the air inside refrigerators, freezers, containers, etc.

[0081] (Other embodiments) The above explanation may be structured as follows:

[0082] The number of first holes (35) provided for each magnetic pole of the rotor (11) may be one or two or more. Furthermore, if two or more first holes (35) are provided for each magnetic pole of the rotor (11), the two or more first holes (35) may be formed such that the condition "the first distance (D1) is shorter than the distance obtained by subtracting the third distance (D3) from the second distance (D2)" is satisfied for each of the two or more first holes (35).

[0083] The position of the first hole (35) is not limited to the central part in the circumferential direction of the portion between the first gap (31) and the second gap (32) (magnetic path portion (22)). The first hole (35) may be located in a different part other than the central part.

[0084] The first hole (35) may be positioned so as to overlap with the radially inner circumference of the first gap (31) in a cross section perpendicular to the axis of rotation (Q), or it may be positioned so as not to overlap with either the first gap (31) or the second gap (32).

[0085] The radially outer shape of the first void (31) is not limited to a shape in which the radially outer wall surface of the first void (31) is convex radially outward. For example, the radially outer wall surface of the first void (31) may be formed in the shape of an arc convex toward the axis of rotation (Q).

[0086] The first magnet (41) may or may not be embedded so as to fill the entire area of ​​the first void (31) without any gaps. Similarly, the second magnet (42) may or may not be embedded so as to fill the entire area of ​​the second void (32) without any gaps.

[0087] The radially inner shape of the first void (31) is not limited to a shape that is convex toward the axis of rotation (Q). For example, the radially inner wall surface of the first void (31) may be formed in a planar shape perpendicular to the axis of symmetry (a plane that is linear in a cross-section perpendicular to the axis of rotation (Q)). By making it planar, the magnet can have a linear portion, making magnet manufacturing easier. It is desirable that the width of the end at the center of the magnetic path (22) be wider than the width of the end in the circumferential direction of the magnetic path (22). In order to realize such a configuration, the radially inner shape of the first void (31) (shape in a cross-section perpendicular to the axis of rotation (Q)) may be the following shape.

[0088] (1) The central surface of the radially inner wall of the first void (31) in the circumferential direction is formed in a planar shape perpendicular to the axis of symmetry (a plane that is straight in a cross section perpendicular to the axis of rotation (Q)). (2) The radially inner wall surface of the first void (31) is an arc-shaped surface that is convex with respect to the axis of rotation (Q), and the center of curvature of the radially inner wall surface of the first void (31) is located radially outward from the center of curvature of the radially outer wall surface of the second void (32) (the arc-shaped wall surface that is convex with respect to the axis of rotation (Q)). (3) The shape is such that the radially inner wall surface of the first void (31) is concave with respect to the axis of rotation (Q). By adopting the shape described above, the width of the central part in the circumferential direction of the magnetic path section (22) can be increased. This allows for a higher q-axis inductance and an increase in reluctance torque. Furthermore, it allows for space to be secured for bolt holes and other components, thereby improving the design flexibility of the rotor core (20).

[0089] Furthermore, the shape of the arc portion (23) is not limited to an arc shape centered on the axis of rotation (Q).

[0090] For example, the arc portion (23) may be an arc shape having two or more centers of curvature. Also, the radial length of the arc portion (23) may be the same or different throughout the entire circumferential region of the arc portion (23). Since the stress acting on the arc portion (23) due to the centrifugal force corresponding to the rotation of the rotor (11) differs depending on the location, the center of curvature and radial length of the arc portion (23) may be changed as described above in accordance with such differences in stress at different locations.

[0091] Furthermore, the arc portion (23) may be a portion through which magnetic flux flows less easily than in the magnetic path portion (22). For example, the radial length of the arc portion (23) may be such that the arc portion (23) does not become a magnetic path (a portion through which magnetic flux flows).

[0092] Furthermore, while embodiments and modifications have been described, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Also, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Moreover, the designations "first," "second," "third," etc., in the specification and claims are used to distinguish the phrases to which these designations are given, and do not limit the number or order of such phrases. [Industrial applicability]

[0093] As explained above, this disclosure is useful as a motor, compressor, refrigeration device, etc. [Explanation of Symbols]

[0094] 10 motors 11 rotors 12 staters 20 rotor cores 21 Base 22 Magnetic circuit section 23. Arc section 30 Shaft hole (2nd hole) 31 First cavity 32 Second cavity 32a Cavity 35 Hole 1 41 First Magnet 42. Second Magnet 42a Magnet 45 Fastening members 50 stator cores 51 York 52 Teeth 52a First Teeth 52b Second Teeth 60 Conductor 61 coils D1 1st distance D2 2nd distance D3 3rd distance D4 4th distance D5 5th distance

Claims

1. A rotor that can rotate around a rotation axis (Q), A rotor core (20) having a first void (31), a second void (32), and a first hole (35) formed for each magnetic pole, A first magnet (41) is provided for each of the aforementioned magnetic poles, A second magnet (42) is provided for each of the aforementioned magnetic poles, The rotor core (20) is fastened by a fastening member (45), In a cross-section perpendicular to the rotation axis (Q), The first magnet (41) is placed in the first gap (31), The second magnet (42) is placed in the second gap (32), The fastening member (45) is positioned in the first hole (35), The second void (32) is located radially inward from the first void (31), The radially outer wall surface of the second void (32) is formed to be convex with respect to the axis of rotation (Q), The first hole (35) is located between the first void (31) and the second void (32). Rotor.

2. In the rotor of claim 1, In the cross-section, the radially outer wall surface of the second void (32) is formed in an arc shape that is convex with respect to the axis of rotation (Q), In the aforementioned cross-section, if the distance between the circumferential end of the first void (31) and the circumferential end of the second void (32) is defined as the first distance (D1), and if a first straight line (L1) is hypothetically drawn as a straight line passing through the center of curvature (Q1) of the radially outer wall surface of the second void (32) closest to the first hole (35) and the center (Q2) of the first hole (35), then the distance between the wall surface of the first void (31) and the wall surface of the second void (32) on this first straight line (L1) is defined as the distance corresponding to the length of the first hole (35) on this first straight line (L1), then the first distance (D1) is shorter than the distance obtained by subtracting the third distance (D3) from the second distance (D2). Rotor.

3. In the rotor of claim 1, The rotor core (20) has a second hole (30) formed therein. In the cross-section, The second hole (30) is located in the central part of the rotor core (20), The radially inner wall surface of the second void (32) is formed to be convex with respect to the axis of rotation (Q), In the aforementioned cross-section, if the distance between the circumferential ends of two adjacent second void portions (32) in the circumferential direction, and the shortest distance between the wall surface of the second void portion (32) and the wall surface of the second hole (30) is defined as the fourth distance (D4), then half of the fourth distance (D4) is shorter than the fifth distance (D5). Rotor.

4. In the rotor of claim 1, The second void (32) is composed of a single continuous void extending from one end to the other in the circumferential direction of the second void (32) in the cross-section. Rotor.

5. In the rotor of claim 1, In the aforementioned cross-section, the shortest distance between the wall surface of the first hole (35) and the wall surface of the first void (31) is shorter than the shortest distance between the wall surface of the first hole (35) and the wall surface of the second void (32). Rotor.

6. A motor comprising a rotor according to any one of claims 1 to 5.

7. A compressor comprising the motor of claim 6.

8. A refrigeration apparatus comprising the motor according to claim 6.

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