Rotating Machinery

Abstract

To provide a rotary machine that can improve power output using reluctance torque.SOLUTION: A rotary machine 1 has a surface magnet type rotor 3 rotatably arranged inside a stator 2. The rotor 3 includes a shaft member 31 disposed along a rotation axis A and a magnet unit 32 provided on the outer circumference of the shaft member 31 that alternately forms different magnetic poles along the circumferential direction. The shaft member 31 is formed to have different cross-sectional areas in d-axis and q-axis directions in the cross-section perpendicular to the rotation axis A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to rotary machines. [Background technology]

[0002] Conventionally, a known rotating machine is a surface magnet rotor and a brushless motor equipped with the rotor, as described in JP 2019-161933 A. This rotor has multiple magnets around the rotating shaft, with magnets of different magnetic poles arranged alternately in the circumferential direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-161933 Summary of the Invention [Problem to be solved by the invention]

[0004] In rotating machines equipped with such surface permanent magnet rotors, it is difficult to improve output by using reluctance torque. That is, since the surface permanent magnet rotor has permanent magnets arranged along the circumferential surface, reluctance torque is not easily generated, and rotation is mainly driven by magnetic torque.

[0005] Therefore, there is a demand for the development of a rotary machine that can improve output by using reluctance torque. [Means for solving the problem]

[0006] A rotating machine according to one aspect of the present disclosure includes a surface-magnet rotor rotatably disposed inside a stator. The rotor includes a shaft member disposed along the rotation axis and magnet sections disposed on the outer periphery of the shaft member, with different magnetic poles arranged alternately along the circumferential direction. The shaft member is formed so that, in a cross section perpendicular to the rotation axis, the cross-sectional area of ​​the magnet sections differs in the d-axis direction and the q-axis direction. According to this rotating machine, because the rotor shaft member is formed so that the cross-sectional area of ​​the magnet sections differs in the d-axis direction and the q-axis direction, the ease of passage of magnetic flux in the shaft member can be differentiated between the d-axis direction and the q-axis direction. This allows for the use of reluctance torque during operation of the rotating machine to improve the output of the rotating machine.

[0007] In a rotary machine according to an embodiment of the present disclosure, the shaft member may be formed so that the cross-sectional area in the d-axis direction is larger than the cross-sectional area in the q-axis direction in a cross section perpendicular to the rotation axis. In this case, the rotor shaft member is formed so that the cross-sectional area in the d-axis direction is larger than the cross-sectional area in the q-axis direction, so that magnetic flux passes more easily in the shaft member in the d-axis direction than in the q-axis direction. This allows the output of the rotary machine to be improved by using reluctance torque when the rotary machine is driven.

[0008] In a rotary machine according to an embodiment of the present disclosure, the shaft member may be formed so that, in a cross section perpendicular to the rotation axis, the cross-sectional area in the q-axis direction is larger than the cross-sectional area in the d-axis direction. In this case, since the rotor shaft member is formed so that the cross-sectional area in the q-axis direction is larger than the cross-sectional area in the d-axis direction, magnetic flux passes more easily in the shaft member in the q-axis direction than in the d-axis direction. This makes it possible to use reluctance torque when driving the rotary machine and improve the output of the rotary machine.

[0009] A rotating machine according to one aspect of the present disclosure includes a surface-magnet rotor rotatably disposed inside a stator. The rotor includes a shaft member disposed along the rotation axis and magnet portions disposed on the outer periphery of the shaft member and forming different magnetic poles alternately along the circumferential direction. The shaft member is formed so that, in a cross section perpendicular to the rotation axis, the cross-sectional lengths of the magnet portions are different in the d-axis direction and the q-axis direction. According to this rotating machine, the rotor shaft member is formed so that the cross-sectional lengths of the magnet portions are different in the d-axis direction and the q-axis direction. This allows for different ease of passage of magnetic flux in the shaft member in the d-axis direction and the q-axis direction. This allows for improved output of the rotating machine by utilizing reluctance torque during operation.

[0010] In a rotary machine according to an embodiment of the present disclosure, the shaft member may be formed so that, in a cross section perpendicular to the rotation axis, the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. In this case, the rotor shaft member is formed so that the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction, so that magnetic flux passes more easily in the shaft member in the d-axis direction than in the q-axis direction. This makes it possible to use reluctance torque when driving the rotary machine and improve the output of the rotary machine.

[0011] In a rotary machine according to an embodiment of the present disclosure, the shaft member may be formed so that, in a cross section perpendicular to the rotation axis, the length of the cross section in the q-axis direction is longer than the length of the cross section in the d-axis direction. In this case, the rotor shaft member is formed so that the length of the cross section in the q-axis direction is longer than the length of the cross section in the d-axis direction, so that magnetic flux passes more easily in the shaft member in the q-axis direction than in the d-axis direction. This makes it possible to use reluctance torque when driving the rotary machine and improve the output of the rotary machine.

[0012] Furthermore, in a rotary machine according to an embodiment of the present disclosure, the stator may generate a rotating magnetic field that precedes the rotor's rotation direction relative to the d-axis direction, and rotate the magnetic field in the rotation direction to rotate the rotor. When the cross-sectional area of ​​the shaft member in the d-axis direction is larger than the cross-sectional area in the q-axis direction, or when the length of the cross section of the shaft member in the d-axis direction is longer than the length of the cross section in the q-axis direction, the stator generates a rotating magnetic field that precedes the rotor in the d-axis direction, thereby generating reluctance torque in the rotor. This can improve the output of the rotary machine.

[0013] Furthermore, in a rotary machine according to an embodiment of the present disclosure, the stator may form a magnetic field that precedes the rotor rotation direction relative to the q-axis direction, and rotate the magnetic field in the rotation direction to rotate the rotor. When the cross-sectional area of ​​the shaft member in the q-axis direction is larger than the cross-sectional area in the d-axis direction, or when the length of the cross section in the q-axis direction is longer than the length of the cross section in the d-axis direction, the stator forms a rotating magnetic field that precedes the rotor in the q-axis direction, thereby generating reluctance torque in the rotor. This can improve the output of the rotary machine.

[0014] In a rotating machine according to an aspect of the present disclosure, the magnet section may include a bonded magnet provided on the outer periphery of the shaft member and having different magnetic poles arranged alternately along the circumferential direction, and a sintered magnet embedded within the bonded magnet. In this case, the provision of the sintered magnet in the magnet section can increase the magnetic force of the magnet section. Furthermore, by placing a low-resistivity sintered magnet within a high-resistivity bonded magnet, the magnetic force of the magnet section can be increased while suppressing eddy current loss.

[0015] A rotating machine according to one aspect of the present disclosure includes a surface-magnet rotor rotatably disposed inside a stator. The rotor includes a shaft member disposed along the rotation axis and magnet portions disposed on the outer periphery of the shaft member and forming alternating magnetic poles along the circumferential direction. The shaft member is shaped so that, in a cross section perpendicular to the rotation axis, the ease of magnetic flux passage is maximized in an angular direction between the d-axis direction and the q-axis direction of the magnet portions. This rotating machine is capable of generating reactance torque because the shaft member is shaped so that, in a cross section perpendicular to the rotation axis, the ease of magnetic flux passage is maximized in an angular direction between the d-axis direction and the q-axis direction. Therefore, even though it is a surface-magnet rotating machine, it is possible to improve output by using reluctance torque.

[0016] In a rotating machine according to an embodiment of the present disclosure, the shaft member may be formed so that, in a cross section perpendicular to the rotation axis, the ease of passage of magnetic flux is maximized in an angular direction midway between the d-axis direction and the q-axis direction of the magnet portion. In this case, by forming the shaft member so that the ease of passage of magnetic flux is maximized in an angular direction midway between the d-axis direction and the q-axis direction, a large reactance torque can be generated. Therefore, even though the rotating machine is a surface magnet type, it is possible to improve output by using reluctance torque.

[0017] In addition, in a rotating machine according to an aspect of the present disclosure, the stator may generate a magnetic field in the q-axis direction and rotate the magnetic field in the rotational direction to rotate the rotor. In this case, by the stator generating a magnetic field in the q-axis direction, it becomes possible to generate large magnetic torque and reactance torque. Therefore, even though it is a surface permanent magnet type rotating machine, it is possible to generate large reluctance torque and improve output. [Effects of the Invention]

[0018] According to the invention of the present disclosure, it is possible to provide a rotary machine that can improve output by using reluctance torque. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view showing an overview of a rotary machine according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of the rotor of the rotary machine of FIG. 1. [Figure 3] FIG. 3 is a perspective view of the rotor of FIG. 2. [Figure 4] FIG. 2 is a block diagram showing an outline of the electrical configuration of the rotary machine of FIG. 1. [Figure 5] FIG. 3 is an explanatory diagram of a magnetic field applied to the rotor of FIG. 2. [Figure 6] 2 is a flowchart showing the operation of the rotary machine of FIG. 1. [Figure 7] 2 is a graph showing the relationship between the current phase angle and the output torque in the rotary machine of FIG. 1. [Figure 8] FIG. 2 is a diagram showing a modification of the rotary machine of FIG. [Figure 9] FIG. 2 is a diagram showing a modification of the rotary machine of FIG. [Figure 10] FIG. 2 is a diagram showing a modification of the rotary machine of FIG. [Figure 11] FIG. 2 is a diagram showing a modification of the rotary machine of FIG. [Figure 12] FIG. 4 is a cross-sectional view showing an overview of a rotary machine according to a second embodiment of the present disclosure. [Figure 13] 13 is an explanatory diagram of a magnetic field applied to a rotor of the rotary machine of FIG. 12. [Figure 14] 13 is a graph showing the relationship between the current phase angle and the output torque in the rotary machine of FIG. 12. [Figure 15] FIG. 10 is a cross-sectional view showing an overview of a rotary machine according to a third embodiment of the present disclosure. [Figure 16] FIG. 10 is a cross-sectional view showing an overview of a rotary machine according to a third embodiment of the present disclosure. [Figure 17] FIG. 10 is a cross-sectional view showing an overview of a rotary machine according to a fourth embodiment of the present disclosure. [Figure 18] 18 is a graph showing the relationship between the current phase angle and the output torque in the rotary machine of FIG. 17. [Figure 19] FIG. 18 is a diagram showing a modification of the rotary machine of FIG. [Figure 20] FIG. 18 is a diagram showing a modification of the rotary machine of FIG. [Figure 21] FIG. 18 is a diagram showing a modification of the rotary machine of FIG. [Figure 22] FIG. 18 is a diagram showing a modification of the rotary machine of FIG. [Figure 23] FIG. 18 is a diagram showing a modification of the rotary machine of FIG. [Figure 24] FIG. 18 is a diagram showing a modification of the rotary machine of FIG. [Figure 25] FIG. 10 is a cross-sectional view showing an overview of a rotary machine according to a fifth embodiment of the present disclosure. [Figure 26] 26 is a graph showing the relationship between the current phase angle and the output torque in the rotary machine of FIG. 25. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated description will be omitted.

[0021] Fig. 1 is a cross-sectional view showing a configuration of a rotary machine according to a first embodiment of the present disclosure, Fig. 2 is a cross-sectional view of a rotor of the rotary machine of Fig. 1.

[0022] As shown in FIG. 1, a rotating machine 1 according to the first embodiment is configured by rotatably arranging a surface magnet type rotor 3 inside a stator 2. The rotating machine 1 is, for example, an electric motor, and generates mechanical energy by rotating the rotor 3 when supplied with electrical energy. The stator 2 generates a magnetic field that rotates around a rotation axis A, causing the rotor 3 to rotate. The stator 2 is housed in a housing 4 and is fixed so as not to rotate or move relative to the housing 4. The rotor 3 is supported by bearings or the like provided in the housing 4, and is mounted rotatably around the rotation axis A.

[0023] The stator 2 is composed of, for example, a core 21 and a coil 22. The core 21 is an iron core that serves as a path for magnetic flux, and has a plurality of teeth 21a formed at equal intervals along the outer periphery of the rotor 3. For example, the core 21 has a cylindrical portion 21b inside which the rotor 3 can be placed, and has a plurality of teeth 21a that protrude from the inner surface of the cylindrical portion 21b toward the rotation axis A. The teeth 21a are portions around which the coil 22 is wound. The tips of the teeth 21a are formed wide. For example, three teeth 21a are formed along the circumferential direction.

[0024] Core 21 is formed, for example, by stacking multiple steel plates in the direction of rotation axis A. By configuring core 21 by stacking steel plates, it is possible to suppress the generation of eddy currents and reduce iron loss. Coils 22 are windings for passing current, and are wound around teeth 21a, generating a magnetic field for rotor 3 due to the flow of current. For example, the magnetic field is formed along the radial direction of rotor 3. Furthermore, by passing current through multiple coils 22 with a phase shift, it is possible to form a magnetic field that rotates around rotation axis A.

[0025] The rotor 3 includes a shaft member 31 disposed along the rotation axis A, and magnet sections 32 provided on the outer periphery of the shaft member 31 and forming different magnetic poles alternately along the circumferential direction. The shaft member 31 is a rod-shaped member and functions as the shaft of the rotary machine 1. The shaft member 31 is formed of a magnetic material such as metal. The shaft member 31 is also formed using a material (e.g., a ferromagnetic material) with higher magnetic permeability than the magnet sections 32. For example, when a bonded magnet is used as the magnet sections 32, the magnetic permeability of the shaft member 31 is more than 100 times higher than that of the magnet sections 32. Therefore, the direction in which magnetic flux can easily pass through the shaft member 31 is the direction in which magnetic flux can easily pass through the rotor 3.

[0026] The magnet portion 32 is provided to cover the outer periphery of the shaft member 31, and is provided, for example, without any other object interposed between the magnet portion 32 and the shaft member 31. However, this does not exclude the presence of an object, such as an adhesive, between the magnet portion 32 and the shaft member 31 to bond them together. The magnet portion 32 is configured with multiple magnetic poles, and for example, a bipolar type configured with two magnetic poles is used. That is, the magnet portion 32 includes a magnet 32a having a north pole on the radially outer periphery side and a magnet 32b having a south pole on the radially outer periphery side. The magnets 32a and 32b are arranged to divide the outer periphery of the shaft member 31 in the circumferential direction, and each magnet covers half of the outer periphery of the shaft member 31.

[0027] The magnets 32a and 32b are formed, for example, from bonded magnets. That is, the magnets 32a and 32b are formed by kneading fine magnets into resin or rubber. Bonded magnets are also called rubber magnets or plastic magnets. By forming the magnets 32a and 32b from bonded magnets, the magnets 32a and 32b can be easily formed to correspond to the shape of the shaft member 31. Note that magnets other than bonded magnets may also be used as the magnets 32a and 32b.

[0028] A sleeve 33 is attached to the outer periphery of the magnet portion 32. The sleeve 33 is a cylindrical member made of a non-magnetic material. By being attached to the outer periphery of the magnet portion 32, the sleeve 33 restrains the magnet portion 32. In other words, the sleeve 33 prevents the magnet portion 32 from coming off the shaft member 31 when the rotor 3 rotates.

[0029] The shaft member 31 is formed so that, in a cross section perpendicular to the rotation axis A, the cross-sectional area differs between the d-axis direction of the magnet portion 32 and the q-axis direction of the magnet portion 32. In other words, when the cross section of the rotor 3 is circular, the shaft member 31 is formed so that the ratio of the cross-sectional area of ​​the shaft member 31 to that of the magnet portion 32 differs between the d-axis direction and the q-axis direction. Furthermore, the shaft member 31 is formed so that, in a cross section perpendicular to the rotation axis A, the cross-sectional length differs between the d-axis direction of the magnet portion 32 and the q-axis direction of the magnet portion 32. The d-axis direction of the magnet portion 32 is the main magnetic flux direction of the magnet portion 32, and is, for example, a direction passing through the circumferential center of the magnet 32a, whose outer periphery is the north pole. The q-axis direction of the magnet portion 32 is a direction along the boundary between the magnet 32a and the magnet 32b. For example, when the magnet portion 32 is a bipolar type, the d-axis direction and the q-axis direction are perpendicular to each other.

[0030] The shaft member 31 is formed, for example, so that the cross-sectional area in the d-axis direction is larger than the cross-sectional area in the q-axis direction in a cross section perpendicular to the rotation axis A. The shaft member 31 is also formed, for example, so that the cross-sectional area in the d-axis direction is longer than the cross-sectional area in the q-axis direction in a cross section perpendicular to the rotation axis A. The shaft member 31 is formed so that the radial cross-section is non-circular at least at the axial position where the magnet portion 32 is provided, for example, so that the cross-section perpendicular to the rotation axis A has both ends of a circle shaved off. In other words, by shaving off both ends of the q-axis direction, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction in a cross-section perpendicular to the rotation axis A, and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. By making the cross-section of the shaft member 31 non-circular, torque transmission performance between the magnet portion 32 and the shaft member 31 can be improved compared to when the cross-section is circular. That is, it is possible to prevent the magnet portion 32 and the shaft member 31 from being displaced relative to each other, and it is possible to reliably rotate the magnet portion 32 and the shaft member 31 as a unit.

[0031] As shown in FIG. 2, in a cross section perpendicular to the rotation axis A, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. For example, if a midpoint line M is set midway between the d-axis direction and the q-axis direction, the cross-sectional area Sd between the d-axis and the midpoint line M in the cross section of the shaft member 31 is larger than the cross-sectional area Sq between the q-axis and the midpoint line M. Therefore, magnetic flux passes more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and magnetic flux passes more easily in the d-axis direction in the rotor 3 than in the q-axis direction. In other words, because the shaft member 31 has a sufficiently high magnetic permeability with respect to the magnet portion 32, making it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3. The ease of magnetic flux passage (composite magnetic permeability) can be expressed by the following equation.

[0032]

number

[0033] In this formula, the ease of magnetic flux passage (composite magnetic permeability) is the sum of the magnetic permeabilities of the materials constituting the rotor 3 on a line that intersects the rotation axis A and extends in the radial direction. This formula calculates the ease of magnetic flux passage in cylindrical coordinates with the rotation axis A as the z-direction, where μ is the magnetic permeability of the material, R is the radius of the rotor 3 in the target cross section, and θ is the angle in the circumferential direction of the rotor 3. In this way, by making it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction, it is possible to generate reluctance torque when the rotating machine 1 is operating. Also, for example, in the cross section of the shaft member 31, the length Ld in the d-axis direction is longer than the length Lq in the q-axis direction. Therefore, it is easier for magnetic flux to pass in the shaft member 31 in the d-axis direction than in the q-axis direction, and it is easier for magnetic flux to pass in the rotor 3 in the d-axis direction than in the q-axis direction. This makes it possible to generate reluctance torque when the rotating machine 1 is operating.

[0034] FIG. 3 is a perspective view of the rotor 3. As shown in FIG. 3, the shaft member 31 of the rotor 3 extends along the rotation axis A and protrudes from the magnet portion 32. In the shaft member 31, an extension portion 311 extending from the magnet portion 32 has a circular cross-sectional shape. The extension portion 311 is a portion that is journaled in the housing 4. The portion of the extension portion 311 that extends outward from the housing 4 is used as the output shaft of the rotating machine 1. The shaft member 31 is formed so that, at least at the axial position where the magnet portion 32 is provided, the cross-sectional area is different in the d-axis direction of the magnet portion 32 and the q-axis direction of the magnet portion 32, and the cross-sectional length is different in the d-axis direction of the magnet portion 32 and the q-axis direction of the magnet portion 32. In other words, at an axial position where the magnet portion 32 is not provided, the shaft member 31 does not need to have a different cross-sectional area in the d-axis direction of the magnet portion 32 and a different cross-sectional length in the d-axis direction of the magnet portion 32 and a different cross-sectional length in the q-axis direction of the magnet portion 32. Furthermore, the shaft member 31 may have a transition portion whose cross-sectional shape changes along the rotation axis A in a cross section perpendicular to the rotation axis A. The transition portion in this embodiment is formed so as to be flush with the end face of the magnet portion 32 in the direction of the rotation axis A.

[0035] FIG. 4 is a block diagram showing an outline of the electrical configuration of the rotating machine 1. As shown in FIG. 4, the three coils 22 of the stator 2 are connected, for example, by a Y connection (star connection). That is, one end of each coil 22 is connected to each other, and the other end is connected to an inverter 91. These coils 22 generate a rotating magnetic field for the rotor 3 when a three-phase AC current is passed through them. The inverter 91 converts DC voltage to AC voltage and applies, for example, a three-phase AC voltage to the coils 22. The inverter 91 may be, for example, a bridge circuit using six power transistors. The inverter 91 operates in response to a control signal from a controller 92 and supplies current to the coils 22. The controller 92 outputs a control signal to the inverter 91 in response to an external operation command. The controller 92 is an electronic control device that controls the rotating machine 1 and is, for example, configured by a computer including a CPU, ROM, and RAM. The inverter 91 and the controller 92 may be integrated into the housing 4 that accommodates the stator 2 and the rotor 3, or may be installed outside the housing 4. The inverter 91 may also be provided inside the controller 92.

[0036] The rotating machine 1 is provided with a sensor 5 that detects the rotational state of the rotor 3. The sensor 5 may be, for example, a magnetic sensor such as a Hall element or a rotary encoder. The sensor 5 is connected to a controller 92, and an output signal from the sensor 5 is input to the controller 92. The controller 92 recognizes the rotational state, including some or all of the rotational positions and rotational speeds of the rotor 3 and the shaft member 31, based on the output signal from the sensor 5. Note that although the sensor 5 is used in this embodiment, the rotational position of the rotor 3 may be detected by sensorless control or the like, and installation of the sensor 5 may be omitted in some cases.

[0037] FIG. 5 is a diagram showing the magnetic field B generated by the stator 2. The direction of the magnetic field B in FIG. 5 is a representative direction of the magnetic field B generated by the stator 2 (the direction of the center of the magnetic field B or the average direction of the magnetic field B) shown by a single magnetic field line. In the rotating machine 1, for example, the magnetic field B is formed so as to be oriented between the d-axis direction and the q-axis direction of the rotor 3. In other words, the stator 2 forms a magnetic field B that precedes the rotation direction DR of the rotor 3 with respect to the d-axis direction, and rotates the magnetic field B in the rotation direction DR to rotate the rotor 3. In FIG. 5, the rotation direction DR is counterclockwise.

[0038] In surface permanent magnet rotating machines (for example, surface permanent magnet motors), it is common for a magnetic field to be formed in the q-axis direction during rotational driving. This is to allow the magnetic torque to act effectively. Since reluctance torque is hardly generated in general surface permanent magnet rotating machines, the magnetic field is formed in the q-axis direction to allow the magnetic torque to act effectively.

[0039] In contrast, in the rotating machine 1 according to the present disclosure, the magnetic field B is formed so as to be oriented between the d-axis direction and the q-axis direction of the rotor 3, thereby enhancing the reluctance torque. In this case, the direction of the magnetic field B may be intermediate between the q-axis direction and the d-axis direction. That is, in the case of a two-pole rotor 3, the magnetic field B may be formed so that the angle θ between the d-axis direction and the direction of the magnetic field B is 45 degrees. By forming the magnetic field B in this manner, the reactance torque can be enhanced. Furthermore, the direction of the magnetic field B may be closer to the q-axis direction than the d-axis direction. That is, in the case of a two-pole rotor 3, the magnetic field B may be formed so that the angle θ between the d-axis direction and the direction of the magnetic field B is greater than 45 degrees and less than 90 degrees. By forming the magnetic field B in this manner, the reactance torque can be enhanced. In the rotating machine 1 according to the present disclosure, the shaft member 31 is flattened in the d-axis direction. Therefore, the magnetic flux passing through the shaft member 31 is oriented approximately in the d-axis direction. This prevents the magnetic field B from canceling out the magnetic force of the magnet section 32.

[0040] Next, the operation of the rotary machine 1 according to the present disclosure will be described.

[0041] FIG. 6 is a flowchart showing the operation of the rotating machine 1, and shows the operation control process of the rotating machine 1. The control process of FIG. 6 is executed by, for example, the controller 92, and this control process operates the rotating machine 1. First, as shown in step S10 (hereinafter simply referred to as "S10", and the same applies to steps after S10), a command signal reading process is performed. This command signal reading process is a process of reading a command signal input to the controller 92. The command signal is a command signal for the operation of the rotating machine 1, and corresponds to, for example, a signal for the rotational speed of the rotating machine 1. This command signal is input to the controller 92 from, for example, an external device or an interface.

[0042] The process proceeds to S12, where a rotational position detection process is performed. This detection process is a process of detecting the rotational position of the rotor 3. For example, the controller 92 detects the position of the magnetic poles of the rotor 3 based on the output signal of the sensor 5. Note that, in this rotational position detection process, the rotational position of the rotor 3 may be detected without using the sensor 5. For example, the controller 92 may detect the rotational position of the rotor 3 by detecting the induced voltage of each coil 22. Next, the process proceeds to S14, where a control signal generation process is performed. The control signal generation process is a process of generating a control signal to be output to the inverter 91. The control signal is generated based on, for example, the command signal of S10 and the detection result of S12. Specifically, the control signal is generated so that the magnetic field B precedes the rotational position of the rotor 3. In other words, the control signal is generated so that the magnetic field B is formed between the d-axis and q-axis directions of the rotor 3, as shown in FIG. 5. By generating the control signal in this manner, the reluctance torque can be improved.

[0043] Furthermore, the control signal may be generated so that the magnetic field B is formed in a direction closer to the q-axis direction than to the d-axis direction. For example, when the rotor 3 has two poles, the control signal may be generated so that the magnetic field B is formed in a direction such that the angle θ with the d-axis direction is greater than 45 degrees and less than 90 degrees. By generating the control signal in this manner, it is possible to improve the reluctance torque.

[0044] Then, the process proceeds to S16 in FIG. 6, where signal output processing is performed. The signal output processing is processing for outputting the control signal generated in S14. For example, the controller 92 outputs the control signal generated in S14 to the inverter 91. As a result, the inverter 91 generates a drive current according to the control signal and outputs the drive current to the rotating machine 1. The drive current is input to the stator 2 of the rotating machine 1, and a current flows through the coil 22 of the stator 2. As a result, a magnetic field B is formed that precedes the rotation direction DR of the rotor 3 with respect to the d-axis direction, and the rotor 3 and the shaft member 31 rotate. At this time, as shown in FIG. 5, the magnetic field B is formed in a direction between the d-axis direction and the q-axis direction of the rotor 3. By forming the magnetic field B in this way, it is possible to improve the reluctance torque. Alternatively, the magnetic field B may be formed in a direction closer to the q-axis direction than the d-axis direction. By forming the magnetic field B in this way, it is possible to improve the reluctance torque.

[0045] Then, the process proceeds to S18 in Fig. 6, where it is determined whether or not to terminate the operation of the rotating machine 1. For example, if a signal to terminate operation has not been input to the controller 92, it is determined not to terminate the operation of the rotating machine 1, and the process returns to S10. Then, the processes of S10 to S16 are continuously executed. On the other hand, for example, if a signal to terminate operation has been input to the controller 92, it is determined to terminate the operation of the rotating machine 1, and the series of control processes in Fig. 6 is terminated.

[0046] As described above, in the rotating machine 1 according to this embodiment, the shaft member 31 of the rotor 3 is formed so that the cross-sectional areas are different in the d-axis direction and the q-axis direction. This makes it possible to make the ease of passage of magnetic flux different in the d-axis direction and the q-axis direction in the shaft member 31, and to make the ease of passage of magnetic flux different in the d-axis direction and the q-axis direction in the rotor 3. This makes it possible to generate reluctance torque when the rotating machine 1 is driven. By using this reluctance torque, it is possible to improve the output of the rotating machine 1.

[0047] Furthermore, in the rotating machine 1 according to this embodiment, the shaft member 31 of the rotor 3 is formed so that the cross-sectional area Sd in the d-axis direction is larger than the cross-sectional area Sq in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3 than in the q-axis direction. This allows reluctance torque to be generated when the rotating machine 1 is driven. Using this reluctance torque can improve the output of the rotating machine 1. For example, as shown in FIG. 7 , the output torque T of the rotating machine 1 is the sum of the magnet torque Tm and the reluctance torque Tr. Adjusting the current phase angle improves the output compared to the output of the magnet torque Tm alone. The vertical axis of FIG. 7 represents the output torque of the rotating machine 1, and the horizontal axis represents the current phase angle. The current phase angle is positive in the direction of rotation relative to the d-axis.

[0048] Furthermore, in the rotating machine 1 according to this embodiment, the shaft member 31 of the rotor 3 is formed so that the cross-sectional length differs between the d-axis direction and the q-axis direction. This allows the ease of passage of magnetic flux in the d-axis direction and the q-axis direction in the shaft member 31 to differ. This makes it possible to generate reluctance torque when the rotating machine 1 is driven. By using this reluctance torque, it is possible to improve the output of the rotating machine.

[0049] Furthermore, in the rotating machine 1 according to this embodiment, the shaft member 31 of the rotor 3 is formed so that the length Ld of the cross section in the d-axis direction is longer than the length Lq of the cross section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3 than in the q-axis direction. This makes it possible to generate reluctance torque when the rotating machine 1 is driven. By using this reluctance torque, the output of the rotating machine 1 can be improved.

[0050] Furthermore, according to the rotating machine 1 of this embodiment, the stator 2 forms a magnetic field B that rotates in the d-axis direction ahead of the rotor 3, thereby utilizing magnetic torque, while forming a magnetic field B that rotates in the longitudinal direction of the axial cross section ahead of the rotor 3, thereby generating reluctance torque in the rotor 3. As a result, the output of the rotating machine 1 can be improved.

[0051] As described above, the first embodiment of the present disclosure has been described, but the rotary machine of the present disclosure is not limited to the rotary machine 1 of the above-described first embodiment. For example, in the above-described first embodiment, the shaft member 31 of the rotor 3 has a circular cross-sectional shape with both ends shaved off, but it may have another cross-sectional shape.

[0052] Specifically, as shown in FIG. 8(a), the shaft member 31 of the rotor 3 may have a circular cross section with inwardly recessed portions 31a formed at both ends. That is, the cross section of the shaft member 31 may have inwardly recessed portions 31a formed along the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3 than in the q-axis direction. This makes it easier for magnetic flux to pass along the d-axis direction, as in the first embodiment described above, and increases reluctance torque.

[0053] 8(b), the cross section of the shaft member 31 may have a plurality of recesses 31a recessed inward at both ends of the circle. For example, the cross section of the shaft member 31 may have three recesses 31a recessed inward along the q-axis direction on both sides of the circle. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque.

[0054] 8(c), the shaft member 31 of the rotor 3 may be formed with a cross section in which convex portions 31b that protrude outward are formed at both ends of the circle. That is, the cross section of the shaft member 31 may have convex portions 31b that protrude outward along the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux can pass more easily along the d-axis direction, thereby increasing reluctance torque.

[0055] 8(d), the cross section of the shaft member 31 may have a plurality of protruding portions 31b protruding outward at both ends of the circle. For example, the cross section of the shaft member 31 may have three protruding portions 31b protruding outward along the d-axis direction on both sides of the circle. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque.

[0056] 9(a), the shaft member 31 of the rotor 3 may be formed with an elliptical cross section. That is, the cross section of the shaft member 31 may be an ellipse with its major axis oriented in the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. This makes it easier for magnetic flux to pass along the d-axis direction, as in the first embodiment described above, and increases reluctance torque.

[0057] Furthermore, as shown in FIG. 9(b), the shaft member 31 of the rotor 3 may have a through hole 31c formed in the q-axis direction. That is, the cross section of the shaft member 31 has a circular center with a through hole 31c formed in the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, by providing such a shaft member 31, the magnetic force of the magnet portion 32 can be increased, thereby increasing magnetic torque.

[0058] 9(c), the shaft member 31 of the rotor 3 may be formed with a rectangular cross section. For example, the cross section of the shaft member 31 may be a rectangle with its long sides oriented in the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux can pass more easily along the d-axis direction, thereby increasing reluctance torque.

[0059] 9(d), the shaft member 31 of the rotor 3 may be composed of multiple shafts 31d. For example, the multiple shafts 31d are arranged so that the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. Specifically, six shafts 31d are arranged, three along the d-axis direction and two along the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily in the d-axis direction, thereby increasing reluctance torque. The cross-section of the shafts 31d may have a shape other than a circle. The number of shafts 31d may be a number other than six.

[0060] 10(a), the shaft member 31 of the rotor 3 may be configured with magnetic members 31e provided outside the circular shape. For example, the shaft member 31 may have magnetic members 31e formed on each side of the circular cross section, spaced apart in the d-axis direction. Multiple magnetic members 31e may be formed on both sides of the circular cross section. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. The cross section of the magnetic members 31e may have a shape other than rectangular.

[0061] 10(b), the shaft member 31 of the rotor 3 may have a circular cross section with both ends shaved off, with non-magnetic bodies 31f attached to the shaved-off portions. That is, the shaft member 31 is configured with non-magnetic bodies 31f attached to both ends in the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, by attaching non-magnetic bodies 31f to the shaft member 31, the shaft member 31 can be reinforced, thereby increasing the strength of the shaft member 31.

[0062] 10(c), the shaft member 31 of the rotor 3 may be formed with a plurality of rectangular cross sections. That is, the cross section of the shaft member 31 may be configured with two rectangles with their long sides oriented in the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3 than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux can pass more easily along the d-axis direction, thereby increasing reluctance torque.

[0063] Furthermore, in the first embodiment described above, the shaft member 31 of the rotor 3 is formed so that the longitudinal direction of the cross section is aligned with the d-axis direction. However, this configuration is not essential. For example, as shown in FIG. 11 , the shaft member 31 of the rotor 3 may be formed so that the longitudinal direction of the cross section is offset from the d-axis direction. Even in this case, by forming the shaft member 31 so that the cross-sectional area in the d-axis direction is larger than the cross-sectional area in the q-axis direction or the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction, the magnetic flux can pass more easily in the shaft member 31 in the d-axis direction than in the q-axis direction, and the magnetic flux can pass more easily in the rotor 3 in the d-axis direction than in the q-axis direction. As a result, similar to the first embodiment described above, the magnetic flux can pass more easily along the d-axis direction, thereby increasing the reluctance torque. Furthermore, the longitudinal direction of the cross section of the shaft member 31 shown in FIGS. 8 to 10 may also be offset from the d-axis direction.

[0064] Next, a rotary machine according to a second embodiment of the present disclosure will be described.

[0065] 12 is a cross-sectional view of a rotor 3a of a rotating machine 1a according to the second embodiment. The rotating machine 1a according to the second embodiment is configured substantially similarly to the rotating machine 1 according to the first embodiment, with only the structure of the rotor 3a being different. That is, the shaft member 31 of the rotor 3 of the rotating machine 1 according to the first embodiment described above is formed so that the cross-sectional area Sd in the d-axis direction is larger than the cross-sectional area Sq in the q-axis direction and the length Ld of the cross-section in the d-axis direction is longer than the length Lq of the cross-section in the q-axis direction. However, the shaft member 31 of the rotor 3a of the rotating machine 1a according to the second embodiment differs from the rotor 3 of the rotating machine 1 according to the first embodiment in that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction and the length Lq of the cross-section in the q-axis direction is longer than the length Ld of the cross-section in the d-axis direction.

[0066] The shaft member 31 is formed so that its cross section perpendicular to the rotation axis A is non-circular, for example, by shaving off both ends of the circular d-axis direction along the q-axis in the cross section perpendicular to the rotation axis A. In other words, by shaving off both ends of the d-axis direction of the shaft member 31, the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction, and the length Lq of the cross section in the q-axis direction is longer than the length Ld of the cross section in the d-axis direction.

[0067] FIG. 13 is a diagram showing the magnetic field B generated by the stator 2. The direction of the magnetic field B in FIG. 13 is a representative direction of the magnetic field B generated by the stator 2 (the direction of the center of the magnetic field B or the average direction of the magnetic field B) shown by a single magnetic field line. In the rotating machine 1a, for example, the magnetic field B is formed in a direction preceding the q-axis direction of the rotor 3a. In other words, the stator 2 forms the magnetic field B that precedes the rotation direction DR of the rotor 3a with respect to the q-axis direction, and rotates the magnetic field B in the rotation direction DR to rotate the rotor 3a. In FIG. 13, the rotation direction DR is counterclockwise.

[0068] In surface permanent magnet rotating machines (for example, surface permanent magnet motors), it is common for a magnetic field to be formed in the q-axis direction during rotational driving. This is to allow the magnetic torque to act effectively. Since reluctance torque is hardly generated in general surface permanent magnet rotating machines, the magnetic field is formed in the q-axis direction to allow the magnetic torque to act effectively.

[0069] In contrast, in the rotating machine 1a according to the present disclosure, the magnetic field B is formed in a direction preceding the q-axis direction, which is the longitudinal direction of the axial cross section of the rotor 3a, thereby increasing the reluctance torque. In this case, the magnetic field B is formed so that the angle θ between the d-axis direction and the direction of the magnetic field B is greater than 90 degrees and less than 135 degrees, for example. In other words, by forming the magnetic field B in this manner, the reluctance torque can be improved.

[0070] FIG. 14 is a graph showing the output torque of the rotating machine 1a. The vertical axis of FIG. 14 represents the output torque of the rotating machine 1a, and the horizontal axis represents the current phase angle. The current phase angle is positive in the direction of rotation relative to the d-axis. As shown in FIG. 14, the output torque T of the rotating machine 1a is the sum of the magnet torque Tm and the reluctance torque Tr. Therefore, by adjusting the current phase angle, it is possible to improve the output torque T compared to the output of the magnet torque Tm alone.

[0071] As described above, the rotating machine 1a according to this embodiment can achieve the same effects as the rotating machine 1 according to the first embodiment. That is, the ease with which magnetic flux passes can be made to differ between the d-axis direction and the q-axis direction in the shaft member 31, and the ease with which magnetic flux passes can be made to differ between the d-axis direction and the q-axis direction in the rotor 3a. This makes it possible to improve the output of the rotating machine 1 by using reluctance torque when the rotating machine 1 is driven.

[0072] Furthermore, in the rotating machine 1a according to this embodiment, the shaft member 31 of the rotor 3a is formed so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction. This allows magnetic flux to pass more easily in the q-axis direction than in the d-axis direction in the shaft member 31, and allows magnetic flux to pass more easily in the q-axis direction than in the d-axis direction in the rotor 3a. This makes it possible to use reluctance torque when driving the rotating machine 1a, thereby improving the output of the rotating machine 1a.

[0073] Furthermore, in the rotating machine 1a according to this embodiment, the shaft member 31 of the rotor 3a is formed so that the length Lq of the cross section in the q-axis direction is longer than the length Ld of the cross section in the d-axis direction. This allows magnetic flux to pass more easily in the q-axis direction in the shaft member 31 than in the d-axis direction, and allows magnetic flux to pass more easily in the q-axis direction in the rotor 3a than in the d-axis direction. This allows the output of the rotating machine 1 to be improved by using reluctance torque when the rotating machine 1 is driven.

[0074] Furthermore, in the rotating machine 1a according to this embodiment, the stator 2 forms a magnetic field B that rotates in the q-axis direction ahead of the rotor 3a, thereby forming a magnetic field B that rotates in the longitudinal direction of the axial cross section ahead of the rotor 3a, thereby generating a reluctance torque in the rotor 3a, thereby improving the output of the rotating machine 1a.

[0075] As described above, the rotary machine 1a of the second embodiment has been described, but is not limited to the above. For example, in the second embodiment described above, the shaft member 31 of the rotor 3 has a circular cross-sectional shape with both ends shaved off, but other cross-sectional shapes are also possible. For example, the rotor 3a may have a shape similar to that of the shaft member 31 shown in FIGS. 8 to 11. In this case, by configuring the rotor 3a so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction, or so that the length Lq of the cross section in the q-axis direction is longer than the length Ld of the cross section in the d-axis direction, it is possible to obtain the same effects as those of the rotary machine 1a described above.

[0076] Next, a rotary machine according to a third embodiment of the present disclosure will be described.

[0077] 15 and 16 are cross-sectional views of rotors of a rotating machine according to a third embodiment. A rotating machine 1b and a rotating machine 1c according to the third embodiment are configured substantially similarly to the rotating machine 1 according to the first embodiment, but differ in the structures of the rotors 3b and 3c. That is, while the rotating machine 1 according to the first embodiment described above includes a two-pole rotor 3, the rotating machines 1b and 1c according to the present embodiment include four-pole rotors 3b and 3c.

[0078] As shown in FIG. 15, the rotating machine 1b includes a rotor 3b with four magnets 32a, 32b, 32c, and 32d arranged alternately in the circumferential direction. The magnet section 32 of the rotor 3b includes magnets 32a, 32b, 32c, and 32d, which are divided and arranged sequentially in the circumferential direction. The magnets 32a and 32c have north poles on their outer sides, while the magnets 32b and 32d have south poles on their outer sides. The rotor 3b also includes a shaft member 31 with a cross-shaped cross section, which is formed so that the cross-sectional area Sd in the d-axis direction is larger than the cross-sectional area Sq in the q-axis direction. When the rotating machine 1b is driven, a magnetic field B is formed to precede the magnetic field B in the d-axis direction. This increases the reluctance torque in addition to the magnetic torque.

[0079] As shown in FIG. 16, the rotating machine 1c includes a rotor 3c with four magnets 32a, 32b, 32c, and 32d arranged alternately in the circumferential direction. The magnet section 32 of the rotor 3c includes magnets 32a, 32b, 32c, and 32d, which are divided and arranged sequentially in the circumferential direction. The magnets 32a and 32c have north poles on their outer sides, while the magnets 32b and 32d have south poles on their outer sides. The rotor 3c also includes a shaft member 31 with a cross-shaped cross section, which is formed so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction. When the rotating machine 1c is driven, a magnetic field B is generated in the q-axis direction. This increases the reluctance torque in addition to the magnetic torque.

[0080] The rotating machines 1b and 1c according to this embodiment have the same effects as the rotating machine 1 according to the first embodiment. That is, it is possible to make the ease of passage of magnetic flux different between the d-axis direction and the q-axis direction in the shaft member 31. This makes it possible to improve the output of the rotating machines 1b and 1c by using reluctance torque when the rotating machine 1 is driven.

[0081] Although the rotating machines 1b and 1c according to the third embodiment have been described above, they are not limited to the above. For example, in the third embodiment, the shaft members 31 of the rotors 3b and 3c have a cross-shaped cross section. However, other cross-sectional shapes may be used. For example, the shaft members 31 shown in FIGS. 8 to 11 may be applied. In this case, the rotors may be configured so that the cross-sectional area Sd in the d-axis direction is larger than the cross-sectional area Sq in the q-axis direction, or so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction, thereby achieving the same effects as the rotating machines 1b and 1c described above. In particular, by using the rotors 3b and 3c with four-fold rotational symmetry about the rotation axis A and forming a two-fold rotational symmetry magnetic field by the stator 2, reluctance torque can be improved. Furthermore, the rotors 3b and 3c may have six, eight, or more different magnetic poles in the circumferential direction. In this case, the shaft members 31 may be configured with six-fold or eight-fold rotational symmetry about the axis, or a cross-sectional shape with rotational symmetry corresponding to the number of magnetic poles.

[0082] Next, a rotary machine according to a fourth embodiment of the present disclosure will be described.

[0083] 17 is a cross-sectional view of a rotor 3d of a rotating machine 1d according to a fourth embodiment. The rotating machine 1d according to the fourth embodiment is configured substantially similarly to the rotating machine 1 according to the first embodiment, with only the structure of the magnet section 32 being different. That is, while the magnet section 32 of the rotating machine 1 according to the first embodiment described above was equipped with magnets 32a and 32b constituted by bonded magnets, the magnet section 32 of the rotating machine 1d according to the fourth embodiment is equipped with a second magnet 321 constituted by a sintered magnet in addition to magnets 32a and 32b constituted by bonded magnets.

[0084] The second magnet 321 is a sintered magnet for strengthening the magnetic force of the magnet section 32 and is embedded inside the magnets 32a and 32b. For example, the second magnet 321 is attached to the shaft member 31 and is in contact with the shaft member 31. Specifically, the second magnets 321 are attached to the ends of the shaft member 31 in the d-axis direction. The second magnet 321 in contact with the magnet 32a having an N pole on the outside is arranged so as to have an N pole on the outside. On the other hand, the second magnet 321 in contact with the magnet 32b having an S pole on the outside is arranged so as to have an S pole on the outside. By providing the second magnet 321 in the rotor 3d, the magnetism of the magnet section 32 can be increased, and the magnetic torque can be improved when the rotating machine 1 is driven. The second magnet 321 is made of a sintered magnet, and therefore has lower electrical resistance than the magnets 32a and 32b, which are bonded magnets. That is, the generation of eddy currents is easily suppressed in the high resistance magnets 32a and 32b, but is difficult to suppress in the low resistance second magnet 321.

[0085] As shown in FIG. 18, the output torque T of the rotating machine 1d is the sum of the bonded magnet torque Tmb, the sintered magnet torque Tms, and the reluctance torque Tr. The addition of the sintered magnet torque Tms improves the output torque T. The bonded magnet torque Tmb is the magnet torque due to the magnets 32a and 32b, and the sintered magnet torque Tms is the magnet torque due to the second magnet 321. The vertical axis of FIG. 18 represents the output torque of the rotating machine 1d, and the horizontal axis represents the current phase angle. When driving the rotating machine 1d, a leading magnetic field B should be formed in the d-axis direction, just like the rotating machine 1 according to the first embodiment.

[0086] The rotating machine 1d according to this embodiment provides the same effects as the rotating machine 1 according to the first embodiment. That is, the ease of passage of magnetic flux in the d-axis direction and the q-axis direction can be made different in the shaft member 31. As a result, the output of the rotating machine 1 can be improved by using reluctance torque when the rotating machine 1 is driven. Furthermore, according to the rotating machine 1d according to this embodiment, the shaft member 31 of the rotor 3a is formed so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction. Therefore, the magnetic flux can pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and the magnetic flux can pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, the output of the rotating machine 1d can be improved by using reluctance torque when the rotating machine 1d is driven. Furthermore, according to the rotating machine 1d according to this embodiment, the shaft member 31 of the rotor 3a is formed so that the length Lq of the cross section in the q-axis direction is longer than the length Ld of the cross section in the d-axis direction. Therefore, it is possible to make it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and it is possible to make it easier for magnetic flux to pass in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, it is possible to improve the output of the rotating machine 1d by using reluctance torque when the rotating machine 1d is driven.

[0087] Furthermore, in the rotating machine 1d according to this embodiment, the magnet section 32 is provided with the second magnet 321, thereby increasing the magnetic force of the magnet section 32. Furthermore, the low-resistance second magnet 321 is arranged radially inward of the high-resistance magnets 32a and 32b. Therefore, since the high-resistance magnets 32a and 32b are located near the outer periphery of the rotor 3d, eddy current loss can be suppressed. Furthermore, by arranging the low-resistance second magnet 321 radially inward of the rotor 3d, the second magnet 321 is not exposed to large magnetic flux changes, and the magnetic force of the magnet section 32 can be increased while suppressing eddy current loss.

[0088] Although the rotary machine 1d of the fourth embodiment has been described above, the present invention is not limited to the above. For example, the configurations of the shaft member 31 shown in Figs. 8 to 11 may be applied.

[0089] Specifically, as shown in FIG. 19(a), the shaft member 31 of the rotor 3 may have a circular cross section with recesses 31a recessed inward at both ends. That is, the cross section of the shaft member 31 may have recesses 31a recessed inward along the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the fourth embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the installation of the second magnet 321 strengthens the magnetic torque, thereby improving output torque.

[0090] Furthermore, as shown in FIG. 19(b), the cross section of the shaft member 31 may have multiple recesses 31a recessed inward at both ends of the circle. For example, the cross section of the shaft member 31 may have three recesses 31a recessed inward along the q-axis direction on both sides of the circle. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the fourth embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the installation of the second magnet 321 strengthens the magnetic torque, thereby improving output torque.

[0091] 19(c), the shaft member 31 of the rotor 3 may be provided with second magnets 321 protruding outward from both ends of the circle. That is, the second magnets 321 may be formed so as to protrude outward along the d-axis direction in the cross section of the shaft member 31. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. Therefore, the shaft member 31 can pass magnetic flux more easily in the d-axis direction than in the q-axis direction, and the rotor 3d can pass magnetic flux more easily in the d-axis direction than in the q-axis direction. As a result, similar to the fourth embodiment described above, magnetic flux can pass more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the provision of the second magnets 321 strengthens the magnetic torque, thereby improving output torque.

[0092] Furthermore, as shown in FIG. 19(d), the cross section of the shaft member 31 may have a plurality of second magnets 321 protruding outward from both ends of the circle. For example, the cross section of the shaft member 31 may have three second magnets 321 protruding outward along the d-axis direction on both sides of the circle. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the installation of the second magnets 321 strengthens the magnetic torque, thereby improving output torque.

[0093] 20(a), the shaft member 31 of the rotor 3 may be formed with an elliptical cross section. That is, the cross section of the shaft member 31 may be an ellipse with its major axis oriented in the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the installation of the second magnet 321 strengthens the magnetic torque, thereby improving output torque.

[0094] 20(b), the shaft member 31 of the rotor 3 may have a through hole 31c formed in the q-axis direction. That is, the cross section of the shaft member 31 has a circular center with a through hole 31c formed in the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the installation of the second magnet 321 strengthens the magnetic torque, thereby improving output torque.

[0095] Furthermore, as shown in FIG. 20(c), the shaft member 31 of the rotor 3 may be formed with a rectangular cross section. For example, the cross section of the shaft member 31 may be a rectangle with its long sides oriented in the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily along the d-axis direction, increasing reluctance torque. Furthermore, the increased magnetic torque improves output torque.

[0096] Furthermore, as shown in FIG. 20(d), the shaft member 31 of the rotor 3 may be composed of multiple shafts 31d. For example, the multiple shafts 31d are arranged so that the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. Specifically, six shafts 31d are arranged, three along the d-axis direction and two along the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily in the d-axis direction, thereby increasing reluctance torque. Furthermore, the output torque can be improved by increasing the magnetic torque. The cross-section of the shafts 31d may have a shape other than circular.

[0097] Furthermore, as shown in FIG. 21(a), the shaft member 31 of the rotor 3 may be configured with a magnetic member 31e provided outside the circular shape. For example, the shaft member 31 may have magnetic members 31e formed on each side of the circular cross section, spaced apart in the d-axis direction. Multiple magnetic members 31e may be formed on both sides of the circular cross section. The second magnet 321 is annularly formed between the central circular portion of the shaft member 31 and the magnetic member 31e. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the cross-sectional length in the d-axis direction is longer than the cross-sectional length in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the increased magnetic torque improves output torque. The cross section of the magnetic member 31e may have a shape other than rectangular.

[0098] As shown in FIG. 21B, the shaft member 31 of the rotor 3 may have a circular cross-sectional shape with both ends shaved off, with non-magnetic bodies 31f provided in the shaved-off portions. That is, the shaft member 31 is configured with non-magnetic bodies 31f attached to both ends in the q-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross-section in the d-axis direction is longer than the length of the cross-section in the q-axis direction. This allows magnetic flux to pass more easily in the d-axis direction in the shaft member 31 than in the q-axis direction, and allows magnetic flux to pass more easily in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment, magnetic flux passes more easily along the d-axis direction, thereby increasing reluctance torque. Furthermore, the output torque can be improved by increasing the magnetic torque. Furthermore, providing the non-magnetic bodies 31f on the shaft member 31 reinforces the shaft member 31, thereby increasing the strength of the shaft member 31.

[0099] Furthermore, as shown in FIG. 21(c), the shaft member 31 of the rotor 3 may be formed with multiple rectangular cross sections. That is, the cross section of the shaft member 31 may be composed of two rectangles with their long sides oriented in the d-axis direction. Even in this case, the cross-sectional area of ​​the shaft member 31 in the d-axis direction is larger than the cross-sectional area in the q-axis direction, and the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. This makes it easier for magnetic flux to pass in the d-axis direction in the shaft member 31 than in the q-axis direction, and makes it easier for magnetic flux to pass in the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment described above, magnetic flux passes more easily along the d-axis direction, increasing reluctance torque. Furthermore, the increased magnetic torque improves output torque.

[0100] Furthermore, in the fourth embodiment described above, the shaft member 31 of the rotor 3d is formed so that the longitudinal direction of the cross section is aligned with the d-axis direction. However, this configuration is not essential. For example, as shown in FIG. 22, the shaft member 31 of the rotor 3 may be formed so that the longitudinal direction of the cross section is offset from the d-axis direction. Even in this case, by forming the shaft member 31 so that the cross-sectional area in the d-axis direction is larger than the cross-sectional area in the q-axis direction or the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction, the magnetic flux can pass more easily in the shaft member 31 in the d-axis direction than in the q-axis direction. This makes it easier for the magnetic flux to pass along the d-axis direction in the rotor 3d than in the q-axis direction. As a result, similar to the first embodiment described above, the magnetic flux can pass more easily along the d-axis direction, thereby increasing the reluctance torque. Furthermore, the output torque can be improved by increasing the magnetic torque. Furthermore, the shaft member 31 shown in FIGS. 19 to 21 may also be formed so that the longitudinal direction of the cross section is offset from the d-axis direction.

[0101] In the fourth embodiment described above, as shown in FIG. 17 , the shaft member 31 of the rotor 3d of the rotary machine 1d is formed so that the cross-sectional area Sd in the d-axis direction is larger than the cross-sectional area Sq in the q-axis direction and the cross-sectional length Ld in the d-axis direction is longer than the cross-sectional length Lq in the q-axis direction. However, the shaft member 31 may be formed so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction and the cross-sectional length Lq in the q-axis direction is longer than the cross-sectional length Ld in the d-axis direction. For example, as shown in FIG. 23 , the shaft member 31 is formed so that the cross-section perpendicular to the rotation axis A is non-circular, and both ends in the d-axis direction of the circular cross-section are shaved off along the q-axis. In other words, by shaving off both ends in the d-axis direction of the shaft member 31, the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction and the cross-sectional length Lq in the q-axis direction is longer than the cross-sectional length Ld in the d-axis direction. The magnet section 32 includes magnets 32a and 32b, which are bonded magnets, as well as a second magnet 321, which is a sintered magnet. The second magnet 321 is a sintered magnet that strengthens the magnetic force of the magnet section 32 and is embedded inside the magnets 32a and 32b. For example, the second magnet 321 is attached to the shaft member 31 and is in contact with the shaft member 31. Specifically, the second magnets 321 are attached to the ends of the shaft member 31 in the d-axis direction. The second magnet 321 in contact with the magnet 32a, which has an N pole on its outer side, is provided so as to have an N pole on its outer side. On the other hand, the second magnet 321 in contact with the magnet 32b, which has an S pole on its outer side, is provided so as to have an S pole on its outer side. By providing the second magnet 321 in the rotor 3d, the magnetism of the magnet section 32 can be enhanced, thereby improving the magnetic torque when the rotating machine 1d is driven. The second magnet 321, which is a sintered magnet, has lower electrical resistance than the magnets 32a and 32b, which are bonded magnets. That is, the generation of eddy currents is easily suppressed in the high resistance magnets 32a and 32b, but is difficult to suppress in the low resistance second magnet 321.

[0102] As shown in FIG. 24, the output torque T of the rotating machine 1d in FIG. 23 is the sum of the bonded magnet torque Tmb, sintered magnet torque Tms, and reluctance torque Tr. The addition of the sintered magnet torque Tms improves the output torque T. The bonded magnet torque Tmb is the magnet torque due to the magnets 32a and 32b, and the sintered magnet torque Tms is the magnet torque due to the second magnet 321. The vertical axis of FIG. 24 represents the output torque of the rotating machine 1d, and the horizontal axis represents the current phase angle. When driving the rotating machine 1d, a leading magnetic field B should be formed in the q-axis direction, just like the rotating machine 1a according to the second embodiment.

[0103] The rotating machine 1d thus configured provides the same effects as the rotating machine 1d according to the fourth embodiment. That is, the output of the rotating machine 1d can be improved by using reluctance torque when the rotating machine 1d is driven. Furthermore, by providing the second magnet 321 in the magnet section 32, the magnetic force of the magnet section 32 can be increased. Furthermore, by disposing the low-resistance second magnet 321 radially inside the high-resistance magnets 32a and 32b, eddy current loss can be suppressed. Furthermore, by disposing the low-resistance second magnet 321 radially inside the rotor 3d, the second magnet 321 is not exposed to large magnetic flux changes, and the magnetic force of the magnet section 32 can be increased while suppressing eddy current loss.

[0104] 19 to 21 may also be formed so that the cross-sectional area Sq in the q-axis direction is larger than the cross-sectional area Sd in the d-axis direction, and so that the length Lq of the cross section in the q-axis direction is longer than the length Ld of the cross section in the d-axis direction. Even in these cases, it is possible to make the ease of passage of magnetic flux different between the d-axis direction and the q-axis direction in the shaft member 31. This makes it possible to use reluctance torque when driving the rotary machine 1d to improve the output of the rotary machine 1d.

[0105] Furthermore, while the fourth embodiment described above includes a two-pole rotor 3d as shown in FIG. 17 , a four-pole rotor may also be provided. For example, a rotary machine 1d may include a rotor 3d having four magnets with different magnetic poles arranged alternately in the circumferential direction. That is, the magnet section 32 of the rotor 3d may have four magnets arranged in a circumferentially divided manner, and the rotor 3b may have a shaft member 31 with a cross-shaped cross section. Even in this case, as in the fourth embodiment described above, the cross-sectional area Sd of the shaft member 31 in the d-axis direction may be larger than the cross-sectional area Sq in the q-axis direction, thereby increasing reluctance torque. Furthermore, the rotor 3d may also include six, eight, or more different magnetic poles in the circumferential direction. In this case, the shaft member 31 may have a cross-sectional shape that is six-fold rotationally symmetric, eight-fold rotationally symmetric, or rotationally symmetric corresponding to the number of magnetic poles.

[0106] Next, a rotary machine according to a fifth embodiment of the present disclosure will be described.

[0107] FIG. 25 is a cross-sectional view of a rotor 3e of a rotating machine 1e according to a fifth embodiment. The rotating machine 1e according to the fifth embodiment is configured substantially similarly to the rotating machine 1 according to the first embodiment, but the structure of the rotor 3e is different. That is, the shaft member 31 of the rotor 3 of the rotating machine 1 according to the first embodiment is formed so that the cross-sectional area Sd in the d-axis direction is larger than the cross-sectional area Sq in the q-axis direction and the cross-sectional length Ld in the d-axis direction is longer than the cross-sectional length Lq in the q-axis direction. However, the shaft member 31 of the rotor 3e of the rotating machine 1e according to the fifth embodiment differs from the rotor 3 of the rotating machine 1 according to the first embodiment in that it is formed so that the ease of passage of magnetic flux is maximized in an angular direction between the d-axis direction and the q-axis direction in a cross section perpendicular to the rotation axis A. For example, the rotating machine 1e according to this embodiment can use the stator 2 shown in FIG. 1 and is driven by the electrical configuration shown in FIG. 4 and the operation control shown in FIG. 6.

[0108] The shaft member 31 is formed so that its cross section perpendicular to the rotation axis A is non-circular and so that it is elongated in an angular direction between the d-axis and q-axis directions. For example, the shaft member 31 is formed by linearly cutting off both ends of the circle in a cross section perpendicular to the rotation axis A, so that it is elongated in an angular direction between the d-axis and q-axis directions. The cross-sectional shape of the shaft member 31 may be formed so that it is elongated in an angular direction intermediate between the d-axis and q-axis directions. In other words, when the angle between the d-axis and q-axis is 90 degrees, the angle between the longitudinal direction L of the shaft member 31 and the d-axis may be 45 degrees. In this way, by elongating the shaft member 31 in an angular direction between the d-axis and q-axis directions, the ease of passage of magnetic flux is maximized in an angular direction between the d-axis and q-axis directions. Furthermore, by elongating the shaft member 31 in an angular direction intermediate between the d-axis and q-axis directions, the ease of passage of magnetic flux is maximized in an angular direction intermediate between the d-axis and q-axis directions.

[0109] As shown in FIG. 25, in the rotating machine 1e, for example, a magnetic field B is formed in the q-axis direction of the magnet section 32. That is, the stator 2 forms the magnetic field B in the q-axis direction, and rotates the magnetic field B in a rotation direction DR to rotate the rotor 3e. In FIG. 25, the rotation direction DR is the direction in which the rotor 3e rotates, which is counterclockwise in this case. In the rotating machine 1e, by forming the magnetic field B in the q-axis direction, it is possible to generate a reluctance torque in addition to the magnet torque, thereby improving the output torque.

[0110] FIG. 26 is a graph showing the output torque of the rotating machine 1e. The vertical axis of FIG. 26 represents the output torque of the rotating machine 1e, and the horizontal axis represents the current phase angle. As shown in FIG. 26, the output torque T of the rotating machine 1e is the combined torque of the magnet torque Tm and the reluctance torque Tr. Therefore, by adjusting the current phase angle, it is possible to improve the output torque T compared to the output of only the magnet torque Tm. It can be seen that when the current phase angle is 90 degrees, that is, when a magnetic field B is formed in the q-axis direction at 90 degrees from the d-axis, the output torque of the rotating machine 1e is at its maximum.

[0111] As described above, in the rotating machine 1e according to this embodiment, the shaft member 31 is formed so that the ease of passage of magnetic flux is maximized in an angular direction between the d-axis direction and the q-axis direction in a cross section perpendicular to the rotation axis A. This makes it possible to generate reactance torque. Furthermore, the shaft member 31 may be formed so that the ease of passage of magnetic flux is maximized in an angular direction intermediate between the d-axis direction and the q-axis direction, making it possible to effectively improve reactance torque.

[0112] In the rotating machine 1e according to this embodiment, a magnetic field B is formed in the q-axis direction, and the magnetic field B is rotated to rotate the rotor 3e, thereby obtaining a large magnetic torque and a large reactance torque. As a result, the output of the rotating machine 1e can be significantly improved.

[0113] As described above, the rotating machine 1e of the fifth embodiment has been described, but is not limited to the above. For example, in the fifth embodiment described above, the shaft member 31 of the rotor 3e has a circular cross-sectional shape with both ends shaved off, but other cross-sectional shapes are also possible. For example, the shaft member 31 may have a shape similar to that of the shaft member 31 shown in FIGS. 8 to 11. The shaft member 31 may also have a shape similar to that of the shaft member 31 shown in FIGS. 15 to 17 and 19 to 21. Even in these cases, the shaft member 31 is formed so that the ease of passage of magnetic flux is maximized in the angular direction between the d-axis direction and the q-axis direction in a cross section perpendicular to the rotation axis A, thereby achieving the same effects as those of the rotating machine 1e described above.

[0114] Although the rotary machines according to the embodiments of the present disclosure have been described above, the rotary machines according to the present disclosure are not limited to those described above. The rotary machines according to the present disclosure can be embodied in various modified forms without departing from the spirit of the claims.

[0115] For example, in each of the above-described embodiments, a rotating machine using a stator 2 having three teeth 21a has been described, but the rotating machine may also use a stator having a number of teeth other than three.

[0116] Furthermore, a type other than two-pole and four-pole rotors may be used as the rotor 3. For example, a rotary machine having a rotor with six or more poles may be used.

[0117] Furthermore, in each of the above-described embodiments, the rotor 3 is provided with the sleeve 33, but a rotor without the sleeve 33 may also be used.

[0118] In addition, in the above-described embodiments, the rotating machine is applied to an electric motor, but the rotating machine may be applied to other devices. For example, the rotating machine may be applied to an electric generator or a motor generator. [Explanation of symbols]

[0119] 1 Rotating Machinery 2 Stator 3 rotor 4. Housing 21 cores 21a Teeth 21b Cylindrical part 22 coils 31 Shaft member 32 Magnet section 32a Magnet 32b Magnet 33 Sleeve 311 Extension part A rotation axis B magnetic field Sd, Sq cross section Ld, Lq length

Claims

1. In a rotating machine in which a surface magnet type rotor is rotatably arranged inside a stator, the rotor includes a shaft arranged along a rotation axis and configured as a single member, and a magnet portion provided on an outer circumferential side of the shaft and forming different magnetic poles alternately along a circumferential direction, The shaft is formed so that its longitudinal direction is in an angular direction between the d-axis direction of the magnet portion and the q-axis direction of the magnet portion in a cross section perpendicular to the rotation axis. Rotating machinery.

2. The shaft is formed so that, in a cross section perpendicular to the rotation axis, the length of the cross section in the d-axis direction is longer than the length of the cross section in the q-axis direction. The rotary machine according to claim 1 .

3. The shaft is formed so that, in a cross section perpendicular to the rotation axis, the length of the cross section in the q-axis direction is longer than the length of the cross section in the d-axis direction. The rotary machine according to claim 1 .

4. The stator forms a magnetic field that precedes the rotation direction of the rotor with respect to the d-axis direction, and rotates the magnetic field in the rotation direction to rotate the rotor. The rotary machine according to claim 2 .

5. The stator forms a magnetic field that precedes the rotation direction of the rotor in the q-axis direction, and rotates the magnetic field in the rotation direction to rotate the rotor. The rotary machine according to claim 3 .

6. The magnet portion includes a bonded magnet provided on the outer periphery of the shaft and having different magnetic poles alternately arranged along the circumferential direction, and a sintered magnet embedded inside the bonded magnet. The rotary machine according to any one of claims 1 to 5.

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