Rotating Machine

Abstract

The rotating machine (100) includes a rotor (1) that rotates around a rotating shaft (AX), a stator (2) that is disposed on the outer or inner circumference of the rotor (1) across a gap (4) from the rotor (1), and a support member (3) that is disposed on at least one side of the rotor (1) in the axial direction along the rotating shaft (AX) and supports the rotor (1) so as to limit the displacement of the rotor (1) in the axial direction and in the tilt direction. At least one of the rotor (1) and the stator (2) has an iron core. At least the other of the rotor (1) and the stator (2) has a magnetic force generating member. The iron core and the magnetic force generating member are disposed so that the displacement of the rotor (1) in the axial direction and in the tilt direction is restored by the force of the stator (2) magnetically attracting the rotor (1). The rotor (1) is supported by the support member (3) at a position displaced in the axial direction relative to the stator (2).

Description

[Technical field]

[0001] The present disclosure relates to a rotating machine in which a rotor is supported without contact with a stator. [Background technology]

[0002] Conventionally, rotating machines such as magnetic bearings and bearingless motors in which a rotor is supported without contact with a stator are known. A magnetic bearing has a function of generating a supporting force for supporting a rotor without contact with a stator. A bearingless motor has a function as an electric motor that generates torque and a function as a magnetic bearing that generates a supporting force for supporting a rotor without contact with a stator, on the same magnetic circuit. In order to support a rotor without contact with a stator, it is necessary to actively control all five degrees of freedom of the rotor except for the direction of rotation around the rotation axis, or to make a passively stable structure without actively controlling some of the five degrees of freedom of the rotor except for the direction of rotation around the rotation axis.

[0003] The five degrees of freedom refer to one degree of freedom in the axial direction, two degrees of freedom in the radial direction, and two degrees of freedom in the tilt direction. The axial direction is the direction parallel to the rotor's rotation axis (direction along the Z axis). The radial direction is the direction perpendicular to the rotor's rotation axis, and includes two directions: the direction along the X axis perpendicular to the Z axis, and the direction along the Y axis perpendicular to the Z axis and the X axis. The tilt direction is the direction of rotation around the X axis (θ x ) and the rotation direction around the Y axis (θ y ) Passively stable means that the rotor will try to return to a specific position without the need to sense the rotor position and control the value of the current.

[0004] Generally, a two-degree-of-freedom control type rotating machine uses sensors to detect the rotor position for only two of the five degrees of freedom mentioned above, the radial direction (directions along the X-axis and Y-axis), and adjusts the rotor's support force in the radial direction so that the detected position matches the target position. In other words, a two-degree-of-freedom control type rotating machine actively controls only the radial direction, and does not actively control the three degrees of freedom in the axial and tilt directions, making it a passively stable structure.

[0005] As a technique for making a passively stable structure with respect to three degrees of freedom in the axial direction and the tilt direction, a technique that utilizes the attractive force generated between the permanent magnet of the rotor and the iron core of the stator is known. For example, Patent Document 1 describes a technique in which, when the rotor is displaced from the ideal position in the axial direction, a force that magnetically attracts the rotor is generated by the magnetic flux flowing between the permanent magnet of the rotor and the iron core of the stator, and a restoring force that returns the axial displacement of the rotor acts on the rotor. Patent Document 1 also describes a technique in which, when the rotor is tilted from the ideal position in the two degrees of freedom in the tilt direction, a force that magnetically attracts the rotor is generated by the magnetic flux flowing between the permanent magnet of the rotor and the iron core of the stator, and a restoring torque that returns the tilt of the rotor acts on the rotor. The restoring force becomes larger in proportion to the axial displacement of the rotor. The restoring torque becomes larger in proportion to the displacement of the rotor around the X-axis and the Y-axis. Hereinafter, the axial displacement of the rotor, the displacement of the rotor around the X-axis, and the displacement of the rotor around the Y-axis may be collectively referred to as the displacement of the rotor.

[0006] In either case, the rotor moves toward an ideally aligned state. As a result, the rotor's rigidity can be ensured for the three degrees of freedom in the axial and tilt directions by the magnetic flux generated by the permanent magnets. By making the rotor positively rigid in the axial and tilt directions in this way, a passively stable structure can be achieved for the three degrees of freedom in the axial and tilt directions. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2005-121157 A Summary of the Invention [Problem to be solved by the invention]

[0008] In the technology disclosed in Patent Document 1, the stability of the rotor in the axial and tilt directions depends only on the restoring force and restoring torque due to the magnetic flux generated by the permanent magnets. However, there is a problem in that if the restoring force and restoring torque proportional to the rotor displacement are generated as in the technology disclosed in Patent Document 1, it is not possible to suppress rotor vibration when it occurs in the axial and tilt directions.

[0009] The present disclosure has been made in consideration of the above, and aims to provide a rotating machine that can suppress vibration of the rotor in the axial and inclination directions while having a passively stable structure with respect to three degrees of freedom in the axial and inclination directions of the rotor. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, a rotating machine according to the present disclosure includes a rotor that rotates around a rotation axis, a stator that is disposed on the outer or inner circumference of the rotor across a gap from the rotor, and a support member that is disposed on at least one side of the rotor in the axial direction along the rotation axis and supports the rotor so as to limit displacement of the rotor in the axial direction and in the tilt direction; a frame that houses the rotor, the stator and the support member; At least one of the rotor and the stator has an iron core. At least the other of the rotor and the stator has a magnetic force generating member. The iron core and the magnetic force generating member are arranged so that the force of the stator magnetically attracting the rotor restores the axial and inclined displacements of the rotor. The rotor is supported by a support member at a position displaced axially relative to the stator. The support member is fixed to the frame directly or indirectly via another member.The axial and tilt directions of the rotor are passively stabilized by the force of the stator magnetically attracting the rotor without contact and by the support members that support the rotor, while the radial direction of the rotor is actively stabilized by the radial support force that supports the rotor against the stator without contact and is generated by passing current through the stator windings. Effect of the Invention

[0011] The rotating machine according to the present disclosure has an advantage in that it is possible to suppress vibration of the rotor in the axial and tilt directions while having a passively stable structure with respect to three degrees of freedom in the axial and tilt directions of the rotor. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a configuration of a rotating machine according to a first embodiment; [Diagram 2] FIG. 1 is a cross-sectional view showing a configuration of a rotating machine according to a first embodiment, illustrating a radial support force acting on a rotor; [Diagram 3] FIG. 1 is a cross-sectional view showing a configuration of a rotating machine according to a first embodiment, illustrating an axial force acting on a rotor; [Figure 4] FIG. 1 is a cross-sectional view showing a configuration of a rotating machine according to a first modified example of the first embodiment. [Diagram 5] FIG. 11 is a cross-sectional view showing a configuration of a rotating machine according to a second modified example of the first embodiment. [Figure 6] FIG. 13 is a perspective view showing a configuration of a rotating machine according to a second embodiment. [Figure 7] FIG. 11 is a cross-sectional view showing a configuration of a rotating machine according to a third embodiment. [Figure 8] FIG. 13 is a cross-sectional view showing a configuration of a rotating machine according to a modification of the third embodiment. [Figure 9] FIG. 13 is a perspective view showing a configuration of a support member for a rotating machine according to a fourth embodiment. [Figure 10] FIG. 13 is a diagram showing a configuration of a rotor of a rotating machine according to a modification of the fourth embodiment, when the rotor is viewed in the axial direction. [Figure 11]FIG. 13 is a perspective view showing a configuration of a part of a stator core of a rotating machine according to a fifth embodiment. [Figure 12] FIG. 13 is a cross-sectional view showing a configuration of a rotating machine according to a fifth embodiment, illustrating an axial force acting on a rotor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotating machine according to an embodiment will be described in detail below with reference to the drawings.

[0014] Embodiment 1 FIG. 1 is a perspective view showing a configuration of a rotating machine 100 according to a first embodiment. In FIG. 1, for ease of understanding, the rotating machine 100 is shown cut in half along the axial direction. In FIG. 1, cross-sectional hatching is omitted. As shown in FIG. 1, the rotating machine 100 includes a rotor 1, a stator 2, and a support member 3. Although not shown, the rotating machine 100 includes a frame that houses the rotor 1, the stator 2, and the support member 3, a shaft provided at the center of the rotor 1, and the like. The rotor 1 rotates relative to the stator 2 about a rotation axis AX.

[0015] Hereinafter, when describing the directions of each component of the rotating machine 100, the direction parallel to the rotation axis AX is referred to as the axial direction, the direction perpendicular to the rotation axis AX is referred to as the radial direction, and the direction of rotation about the rotation axis AX is referred to as the circumferential direction. The X-axis, Y-axis, and Z-axis shown in each drawing are three axes perpendicular to each other. The Z-axis is parallel to the rotation axis AX. The direction along the Z-axis (Z-axis direction) is parallel to the axial direction. The X-axis and Y-axis are perpendicular to the rotation axis AX. The direction along the X-axis (X-axis direction) is a direction perpendicular to the axial direction and is included in the radial direction. The direction along the Y-axis (Y-axis direction) is a direction perpendicular to the axial direction and is included in the radial direction. Hereinafter, when there is no need to distinguish between the X-axis direction and the Y-axis direction, they will be collectively referred to as the XY-axis direction. In addition, the rotation direction θ around the X-axis x and the rotation direction around the Y axis θ yWhen there is no distinction between the Z axis and the Z direction, they are collectively referred to as the tilt direction. For each axis, the direction of the arrow is the positive direction, and the direction opposite to the arrow is the negative direction. In this embodiment, the case where the direction along the rotation axis AX is parallel to the vertical direction is illustrated. In this embodiment, the positive direction of the Z axis is the vertical upward direction, and the negative direction of the Z axis is the vertical downward direction.

[0016] The rotor 1 rotates about a rotation axis AX. The rotor 1 has a rotor core 1a and a plurality of permanent magnets 1b. In this embodiment, the rotor core 1a has a cylindrical shape. A through hole 1c extending in the axial direction is formed at the center of the rotor core 1a. A shaft (not shown) is disposed in the through hole 1c.

[0017] The multiple permanent magnets 1b are arranged on the outer periphery of the rotor core 1a. The multiple permanent magnets 1b are arranged at equal angles in the circumferential direction. The permanent magnets 1b, which are magnetic force generating members, may be fixed to the rotor core 1a by magnetic force, or may be fixed to the rotor core 1a by a fixing member such as an adhesive. In this embodiment, the permanent magnets 1b are attached to the surface of the rotor core 1a, but may be embedded inside the rotor core 1a.

[0018] The stator 2 is disposed on the outer periphery of the rotor 1, separated from the rotor 1 by a gap 4. The stator 2 has a stator core 2a, which is an iron core, and a plurality of windings 2b. The stator core 2a and the windings 2b constitute an electromagnet, which is a magnetic force generating member.

[0019] In this embodiment, the stator core 2a has a cylindrical shape. The stator core 2a has a plurality of teeth 2c arranged in a row in the circumferential direction, and a back yoke portion 2d that connects the plurality of teeth 2c at the outer periphery of each tooth 2c. The plurality of teeth 2c are arranged radially about the rotation axis AX. The plurality of teeth 2c are arranged at equal angles in the circumferential direction. The back yoke portion 2d is formed in a cylindrical shape.

[0020] The winding 2b is wound around each of the teeth 2c and generates a magnetic field for rotating the rotor 1 in the circumferential direction.

[0021] The support member 3 is a member disposed at least on one side of the rotor 1 in the axial direction along the rotation axis AX, and supports the rotor 1 so as to limit the displacement of the rotor 1 in the axial direction and the tilt direction. In this embodiment, the axial direction along the rotation axis AX is parallel to the vertical direction, and the support member 3 is disposed vertically below the rotor 1. The shape of the support member 3 is cylindrical in this embodiment, but is not particularly limited as long as it can support the rotor 1. The shape of the support member 3 is hollow in this embodiment, but may be solid. The support member 3 is fixed to a frame (not shown). In FIG. 1, in order to clearly show the difference between the support member 3 and the rotor 1, the inner diameter of the support member 3 is shown to be smaller than the inner diameter of the rotor 1, but is not limited to the illustrated example. The inner diameter of the support member 3 may be larger than the inner diameter of the rotor 1, or the inner diameter of the support member 3 may be the same as the inner diameter of the rotor 1.

[0022] The support member 3 has a support surface 3a that supports the rotor 1. The support surface 3a is in circumferential contact with one axial surface of the rotor 1. The support member 3 has a low-friction portion that reduces frictional force with the rotor 1. The support member 3 is made of a material with a lower friction coefficient than the rotor 1, so that the low-friction portion may be formed on the whole or part of the support member 3 (the portion of the support member 3 that contacts the rotor 1), or the low-friction portion may be constituted by a lubricant applied to the portion of the support member 3 that contacts the rotor 1. An example of a material with a low friction coefficient is Teflon (registered trademark). An example of a lubricant is grease.

[0023] The rotor 1 is supported by the support member 3 at a position displaced in the axial direction relative to the stator 2. In this embodiment, the rotor 1 is supported by the support member 3 at a position sunken vertically downward relative to the stator 2. The stator core 2a and the permanent magnet 1b are arranged so that the force of the stator 2 magnetically attracting the rotor 1 restores the displacement of the rotor 1 in the axial direction and the tilt direction. The rotor core 1a and the electromagnets are arranged so that the force of the stator 2 magnetically attracting the rotor 1 restores the displacement of the rotor 1 in the axial direction and the tilt direction. In other words, even if the magnetic flux due to the permanent magnet 1b of the rotor 1 is replaced by the magnetic flux due to the electromagnet of the stator 2, a force that attempts to restore the displacement of the rotor 1 in the axial direction and the tilt direction acts on the rotor 1 in the same way.

[0024] Here, referring to FIG. 2, the radial (XY-axis) support force acting on the rotor 1 will be described. FIG. 2 is a cross-sectional view showing the configuration of the rotating machine 100 according to the first embodiment, and is a view for explaining the radial support force acting on the rotor 1. Each cross-sectional view including FIG. 2 is a cross-sectional view along the axial direction. The number of poles when the N-pole permanent magnets 1b and the S-pole permanent magnets 1b are alternately arranged in the circumferential direction on the surface of the rotor core 1a is set to p. A magnetic field with the number of poles p is generated by passing a current through the winding 2b of the stator 2, that is, by passing a fluctuating current i through the winding 2b of the stator 2. When the magnetic field with the number of poles p is rotated by changing the phase of the current to be passed, the rotor 1 is attracted to the rotation of the magnetic field with the number of poles p and rotates. This generates a torque, and the rotation speed and angle of the rotor 1 can be controlled. In addition, when a magnetic field with the number of poles p±2 is generated, an angle at which the density of the magnetic flux 7a increases and an angle at which the density of the magnetic flux 7a decreases are generated in the gap portion 4. This difference in density of the magnetic flux 7a generates a radial (XY axis direction) supporting force that magnetically attracts the rotor 1 radially relative to the stator 2. This allows the rotor 1 to be supported relative to the stator 2 in a non-contact manner.

[0025] If the rotating machine 100 is a general bearingless motor such as a surface magnet type bearingless motor, generating a magnetic field with pole number p±2 generates an angle at which the density of the magnetic flux 7a increases and an angle at which the density of the magnetic flux 7a decreases in the gap portion 4, generating a radial support force (XY axis direction). On the other hand, if the rotating machine 100 is a consequent pole type bearingless motor in which only one of the N pole or S pole permanent magnets 1b is attached between the salient pole rotor core 1a, or a homopolar type bearingless motor in which a salient pole rotor core 1a and a permanent magnet 1b magnetized in the axial direction are used, generating a magnetic field with pole number 2 generates an angle at which the density of the magnetic flux 7a increases and an angle at which the density of the magnetic flux 7a decreases in the gap portion 4, generating a radial support force (XY axis direction).

[0026] Next, the axial force acting on the rotor 1 will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view showing the configuration of the rotating machine 100 according to the first embodiment, and is a diagram for explaining the axial force acting on the rotor 1. Fig. 3 shows a case where gravity mg acts on the rotor 1.

[0027] The rotor 1 is displaced vertically downward relative to the stator 2, i.e., in the axial direction, due to gravity mg. As a result, parts of the rotor 1 and stator 2 do not face each other in the radial direction, and magnetic flux 7b is generated that passes obliquely between the rotor 1 and the stator 2. Figure 3 shows magnetic flux 7b exiting the rotor 1 and entering obliquely the underside of the tip of the teeth 2c of the stator 2, because the rotor 1 is displaced vertically downward relative to the stator 2. Here, the axial displacement of the rotor 1 relative to the stator 2 is z (z<0), and the axial rigidity of the rotor 1 is kz.

[0028] When the rotor 1 is displaced in the axial direction relative to the stator 2, a restoring force f1 is generated in the direction opposite to the axial displacement z of the rotor 1. More specifically, the magnetic flux 7b passing obliquely between the rotor 1 and the stator 2 generates a restoring force f1 that tries to return the rotor 1 to the axial magnetic center, i.e., the position of the rotor 1 at z=0. The restoring force f1 increases in proportion to the axial displacement z of the rotor 1. As described above, if the axial stiffness of the rotor 1 is kz, then f1=-kz×z. The negative sign of the axial stiffness kz of the rotor 1 means that the rotor 1 is attracted to the stator 2 in the direction opposite to the displacement direction of the rotor 1. The restoring force f1 is a magnetic force that supports the rotor 1 in the axial direction, and in the illustrated example, it is a force that tries to move the rotor 1 vertically upward.

[0029] The rotor 1 is also supported in the axial direction by the support members 3. The force with which the rotor 1 is supported in the axial direction by the support members 3 is defined as the support force f2. Since the support force f2 is equal to the remaining component of gravity mg that cannot be supported by the restoring force f1, the following formula (1) is established. f2 = mg - f1 (1)

[0030] On the other hand, if we assume that the rotor 1 is not displaced in the axial direction relative to the stator 2, that is, z=0, then the restoring force f1=0. In this case, the following formula (2) holds true. f2 = mg (2)

[0031] Therefore, from the above formulas (1) and (2), the restoring force f1 can be increased by making the axial displacement z of the rotor 1 relative to the stator 2 a negative value and increasing its absolute value, i.e., by increasing the amount of displacement of the rotor 1 in the direction of gravity mg acting on the rotor 1 (in the negative direction along the Z axis). This allows the restoring force f1 to support most of the gravity mg, and the remaining component, the supporting force f2, can be reduced. Note that the supporting force f2 is also the force with which the rotor 1 is supported in the tilt direction by the supporting members 3. In other words, the supporting force f2 is the force with which the rotor 1 is supported in the axial and tilt directions by the supporting members 3.

[0032] Although not shown, when the rotor 1 is displaced in the tilt direction relative to the stator 2, a restoring torque is generated in the opposite direction to the displacement of the rotor 1 in the tilt direction. In detail, a restoring torque that returns the rotor 1 to the magnetic center in the tilt direction is generated by the magnetic flux 7b that passes obliquely between the rotor 1 and the stator 2. The restoring torque increases in proportion to the displacement of the rotor 1 in the tilt direction. In this embodiment, for the three degrees of freedom in the axial and tilt directions of the rotor 1, even if the position of the rotor 1 is not detected and the value of the current is not controlled, a passively stable structure can be achieved because the restoring force and restoring torque that return the rotor 1 displaced in the axial and tilt directions to the magnetic center in the axial and tilt directions are generated in the gap portion 4. Since the torque and radial supporting force, the restoring force f1 and the restoring torque are generated in the gap portion 4, the rotating machine 100 can be made smaller and lighter than when the part where the torque and radial supporting force are generated is separated from the part where the restoring force f1 and the restoring torque are generated.

[0033] Next, the effects of the rotating machine 100 according to this embodiment will be described.

[0034] In this embodiment, as shown in FIG. 3, the stator core 2a and the permanent magnet 1b, which is a magnetic force generating member, are arranged so that the stator 2 magnetically attracts the rotor 1 to restore the displacement of the rotor 1 in the axial direction and the tilt direction. In this embodiment, the rotor core 1a and the electromagnet, which is a magnetic force generating member, are arranged so that the stator 2 magnetically attracts the rotor 1 to restore the displacement of the rotor 1 in the axial direction and the tilt direction. In this embodiment, the rotating machine 100 is provided with a support member 3 that is arranged on at least one side of the rotor 1 in the axial direction along the rotation axis AX and supports the rotor 1 so as to limit the displacement of the rotor 1 in the axial direction and the tilt direction. With these configurations, in addition to the restoring force and restoring torque that are generated in proportion to the displacement of the rotor 1, the support member 3 can support the rotor 1 in the axial direction and the tilt direction. Therefore, further displacement of the rotor 1 in the axial direction and the displacement of the rotor 1 in the tilt direction are suppressed. This makes it possible to suppress vibration of the rotor 1 in the axial direction and the tilt direction.

[0035] For example, when an impact is applied to the rotor 1 from outside the rotating machine 100, the vibration generated in the rotor 1 can be suppressed, and the continuation of the vibration generated in the rotor 1 can also be suppressed. In addition, there is a frequency at which the vibration of the rotor 1 is likely to occur, which is determined by the rigidity of the rotor 1 and the mass and moment of inertia of the rotor 1. Even when the value of this frequency coincides with the rotation speed of the rotor 1, the vibration of the rotor 1 can be suppressed by avoiding the resonance phenomenon. Conventionally, it was necessary to pay attention to rotating the rotor 1 so as to avoid the resonance phenomenon, but in this embodiment, by using the support member 3, the rotor 1 can be rotated in a wide operating range without paying attention to avoiding the resonance phenomenon. As described above, in this embodiment, a rotating machine 100 can be obtained that can suppress the vibration of the rotor 1 in the axial direction and the tilt direction while making the structure passively stable with respect to the three degrees of freedom of the rotor 1 in the axial direction and the tilt direction.

[0036] In this embodiment, as shown in FIG. 3, the rotor 1 is supported by the support member 3 at a position displaced in the axial direction relative to the stator 2. With this configuration, the restoring force f1 can be increased and the supporting force f2 can be reduced. For example, the ratio of the restoring force f1 to the supporting force f2 shown in FIG. 3 may be set to, for example, 9:1 or 19:1, so that the supporting force f2 is close to 0. By reducing the supporting force f2 in this manner, the frictional heat generated by the supporting member 3 during the rotation of the rotor 1 is significantly reduced. Furthermore, by reducing the supporting force f2, the wear of the supporting member 3 is reduced, so that the frequency of replacing the supporting member 3 can be reduced and the rotating machine 100 can be operated for a long period of time. Furthermore, by reducing the supporting force f2, the torque loss generated by the physical contact between the rotor 1 and the supporting member 3 can be reduced, and the operating efficiency of the entire rotating machine 100 can be improved. As a result, compared to the case where the supporting member 3 is not present, the vibration of the rotor 1 in the axial direction and the tilt direction can be suppressed while maintaining the torque loss and the operating efficiency of the entire rotating machine 100 at approximately the same level.

[0037] 3, in this embodiment, the support member 3 is in circumferential contact with the rotor 1. With this configuration, the support member 3 supports the rotor 1 over the entire circumference of the rotor 1, so that further displacement of the rotor 1 in the axial direction and displacement of the rotor 1 in the tilt direction can be further suppressed.

[0038] In this embodiment, the support member 3 shown in Fig. 3 includes a low-friction portion that reduces the frictional force with the rotor 1. This configuration reduces the frictional force generated between the rotor 1 and the support member 3, and can provide the same effect as the effect achieved by reducing the support force f2 described in paragraph 0036 above.

[0039] Conventionally, a technique is known in which repulsive magnets functioning as magnetic bearings are arranged on the stator and rotor, respectively, and the repulsive force generated between the repulsive magnets is used to passively stabilize the rotor in three degrees of freedom, ie, the axial direction and the inclination direction. In the conventional technique, there are problems such as the repulsive performance being influenced by the magnetization state of the repulsive magnets and the mounting accuracy of the repulsive magnets, the problem of the repulsive magnets increasing the dimensions and the cost, the performance degradation of the repulsive magnets due to temperature rise, and the thermal demagnetization of the repulsive magnets. In this respect, in the present embodiment, as shown in FIG. 3, the rotor 1 is supported by the support member 3 at a position displaced in the axial direction relative to the stator 2, so that no repulsive magnets are required. In other words, in the present embodiment, the stator 2 generates a force that magnetically attracts the rotor 1, and the rotor 1 can be passively stabilized in three degrees of freedom, ie, the axial direction and the inclination direction, so that no repulsive magnets are required. As a result, in the present embodiment, the occurrence of the above-mentioned problems can be suppressed.

[0040] In the rotating machine 100 shown in FIG. 3, a method can be considered in which the rotor 1 is repelled vertically downward against the stator 2 using a repulsive magnet, and the sum of the gravity mg and the repulsive force is supported by a supporting force f2. However, in this method, the supporting force f2 exceeds the gravity mg of the rotor 1. This causes problems such as an increase in frictional heat generated in the support member 3, an increase in wear of the support member 3, a decrease in the life of the support member 3, and an increase in torque loss. In this regard, in the present embodiment, the restoring force f1 generated between the stator 2 and the rotor 1 makes the supporting force f2 smaller than the gravity mg of the rotor 1, so that the occurrence of the above problems can be suppressed.

[0041] Next, a modification of the first embodiment will be described.

[0042] In this embodiment, as shown in FIG. 1, the rotating machine 100 is an inner rotor type in which the rotor 1 is arranged on the inner circumference of the stator 2, but it may also be an outer rotor type rotating machine 100 in which the rotor 1 is arranged on the outer circumference of the stator 2.

[0043] 1, in this embodiment, the rotation axis AX (Z-axis) of the rotor 1 is parallel to the vertical direction, but the entire rotating machine 100 may be tilted with respect to the vertical direction so that there is an angle difference between the rotation axis AX of the rotor 1 and the vertical direction. In other words, the rotation axis AX of the rotor 1 may be inclined with respect to the vertical direction.

[0044] In this embodiment, as shown in FIG. 3, assuming that the gravity mg acts on the rotor 1, a case where the gravity mg acting on the rotor 1 is partially supported by the support member 3 has been illustrated, but a part of the force other than the gravity mg can also be supported by the support member 3. For example, a load such as a fan or a pump may be attached to the rotor 1. In this case, a reaction force when a fluid is pumped out by the load such as the fan or the pump acts on the rotor 1. As a result, an axial displacement z of the rotor 1 relative to the stator 2 occurs. For this reason, a part of the reaction force acting on the rotor 1 may be supported by the support member 3. Also, when the gravity mg and the reaction force act on the rotor 1, a part of the gravity mg and the reaction force acting on the rotor 1 may be supported by the support member 3. Note that even if the axial direction of the rotor 1 is parallel to the horizontal direction, a reaction force occurs. In other words, even if the rotation axis AX of the rotor 1 is parallel to the horizontal direction, an axial displacement z of the rotor 1 relative to the stator 2 may occur, so the rotation axis AX of the rotor 1 may be parallel to the horizontal direction. Furthermore, when the position of the stator 2 in the axial direction is taken as a reference position, the support member 3 only needs to support the rotor 1 at a position where the rotor 1 is displaced from the reference position in the axial direction in the direction of gravity mg acting on the rotor 1 or in the direction in which a reaction force acting on the rotating rotor 1 is generated. In this way, the support force f2 generated by the support member 3 is reduced by the burden of the axial restoring force f1 generated between the stator 2 and the rotor 1, compared to when the rotor 1 is supported at a position not displaced axially from the reference position.

[0045] 1, the rotor 1 has a permanent magnet 1b, and the stator 2 has a stator core 2a, which is an iron core, but the rotor 1 may have an iron core, and the stator 2 may have a permanent magnet. That is, when a permanent magnet is arranged on a magnetic circuit and the stator 2 magnetically attracts the rotor 1 to restore the displacement of the rotor 1 in the axial and tilt directions, it is sufficient that at least one of the rotor 1 and the stator 2 has an iron core, and at least the other of the rotor 1 and the stator 2 has a permanent magnet.

[0046] In this embodiment, the rotating machine 100 has the permanent magnets 1b provided on the rotor 1, but the rotating machine 100 may have no permanent magnets 1b provided on the rotor 1. For example, the rotating machine 100 may be modified to become a synchronous reluctance motor in which reluctance, which is the difficulty of magnetic flux passing, changes depending on the rotation angle of the rotor 1, by forming salient poles or slits in the rotor core 1a.

[0047] In this embodiment, as shown in Fig. 1, the rotor 1 has a hollow shape, but may have a solid shape. When the rotor 1 has a hollow shape, the hollow space may be used, for example, as a path for wiring or as a flow path for a fluid. Furthermore, the rotor 1 has a hollow shape, so that the weight of the entire rotating machine 100 can be reduced. Furthermore, the rotor 1 has a hollow shape, so that when the rotor 1 generates heat, the heat can be dissipated into the hollow space, thereby improving the cooling effect of the rotor 1.

[0048] In the present embodiment, as shown in Fig. 2, a configuration has been exemplified in which a radial (XY-axis) supporting force acting on the rotor 1 is generated by placing a permanent magnet 1b on a magnetic circuit in addition to flowing a fluctuating current i that contributes to an increase or decrease in the radial (XY-axis) supporting force through the windings 2b, but the present invention is not limited thereto. For example, as shown in Fig. 4, a radial (XY-axis) supporting force acting on the rotor 1 may be generated by flowing a bias current I through each winding 2b in addition to flowing a fluctuating current i that contributes to an increase or decrease in the radial (XY-axis) supporting force through the windings 2b. Fig. 4 is a cross-sectional view showing the configuration of a rotating machine 100A according to a first modified example of the first embodiment.

[0049] The rotor 1 shown in FIG. 4 has only the rotor core 1a, and does not have a permanent magnet 1b. There is no difference in reluctance in the rotor 1. The stator core 2a and the winding 2b form an electromagnet. Here, a case where a supporting force in the X-axis direction is generated will be described. The teeth 2c located in the positive direction of the X-axis direction are wound with the winding 2b1. The teeth 2c located in the negative direction of the X-axis direction are wound with the winding 2b2. A current of I+i (A: Ampere), which is the sum of the bias current I and the fluctuating current i, is passed through the winding 2b1, and a current of Ii (A: Ampere), which is the difference between the bias current I and the fluctuating current i, is passed through the winding 2b2. At this time, the density of the magnetic flux 7a in the gap portion 4 can be increased or decreased.

[0050] In addition, considering that the current is proportional to the density of the magnetic flux 7a and that the force is proportional to the square of the density of the magnetic flux 7a, the force acting on the surface of the rotor 1 facing the gap portion 4 located in the positive direction of the X-axis, is k(I+i) 2 The force acting on the surface of the rotor 1 facing the gap 4 in the negative direction of the X-axis is k(Ii). 2 The difference between these two forces is 4×k×I×i. Therefore, the rotor 1 receives a force of 4×k×I×i in the positive direction in the X-axis direction. In other words, by passing a bias current I through each of the windings 2b1 and 2b2 and then adjusting the fluctuating current i passed through each of the windings 2b1 and 2b2, a support force in the X-axis direction proportional to the magnitude of the fluctuating current i can be generated. If it is desired to generate a support force in the Y-axis direction as well, it is sufficient to adjust the fluctuating current i passed through another winding 2b in the same manner as in the case of generating a support force in the X-axis direction. This allows the rotating machine 100A to function as a magnetic bearing that generates a support force in the radial direction (XY axis direction).

[0051] In this modification, the rotor core 1a and the electromagnet, which is a magnetic force generating member, are arranged so that the stator 2 magnetically attracts the rotor 1 to restore the displacement of the rotor 1 in the axial direction and the tilt direction. With this configuration, in this modification, as in the first embodiment, the rotor 1 can have a passively stable structure with respect to the three degrees of freedom in the axial and tilt directions of the rotor 1, because a restoring force and a restoring torque are generated that cause the rotor 1 displaced in the axial and tilt directions to return to the magnetic center in the axial and tilt directions, even without detecting the position of the rotor 1 and controlling the value of the current. Also, in this modification, as in the first embodiment, the support member 3 can suppress the vibration of the rotor 1 in the axial and tilt directions. At least one of the rotor 1 and the stator 2 has an iron core, and at least the other of the rotor 1 and the stator 2 has a magnetic force generating member. The rotor 1 may have both a permanent magnet 1b and an electromagnet as a magnetic force generating member. In this configuration, the electromagnet is composed of, for example, a rotor core 1a and a winding wound around the rotor core 1a.

[0052] As shown in FIG. 5, the rotating machine 100B may include an adjustment member 5 capable of adjusting the position of the support member 3 in the axial direction. FIG. 5 is a cross-sectional view showing a configuration of the rotating machine 100B according to a second modified example of the first embodiment. FIG. 5 shows a frame 6. The frame 6 is shaped like a cylinder with both ends in the axial direction open. The frame 6 has a peripheral wall portion 6a and an axial end wall 6b. The peripheral wall portion 6a is a cylindrical portion extending in the circumferential direction. One end in the axial direction of the peripheral wall portion 6a is open. The other end in the axial direction of the peripheral wall portion 6a is closed by the axial end wall 6b. The axial end wall 6b is formed with a hole 6c into which a shaft (not shown) is inserted.

[0053] The stator 2 is fitted and fixed to the inner peripheral surface of the peripheral wall portion 6a of the frame 6. The support member 3 is fixed to the axial end wall 6b of the frame 6 via the adjustment member 5. The adjustment member 5 is, for example, a screw. The adjustment member 5 penetrates the axial end wall 6b of the frame 6 from the outer surface to the inner surface in the axial direction. The tip of the adjustment member 5 is inserted into the support member 3. By rotating the screw which is the adjustment member 5, the position of the support member 3 in the axial direction is changed.

[0054] In this modification, the position of the support member 3 in the axial direction can be adjusted by rotating the screw that is the adjustment member 5. Therefore, the position where the support member 3 supports the rotor 1, that is, the axial displacement z of the rotor 1, can be adjusted. This makes it possible to easily change the ratio between the restoring force f1 and the supporting force f2. For example, the value of the supporting force f2 can be changed to the smallest value within a range that is unlikely to cause vibration of the rotor 1 in the axial direction and in the tilt direction. In addition, in this modification, even if a load such as a fan or a pump is attached to the rotor 1 and the gravity mg of the entire rotor 1 changes, or a reaction force acts on the rotor 1 when a fluid is pumped out from the load such as a fan or a pump, the ratio between the restoring force f1 and the supporting force f2 can be quickly and easily changed without disassembling or replacing the entire rotating machine 100B. Therefore, the rotor 1 can be rotated while suppressing the occurrence of vibration of the rotor 1 due to the change in the gravity mg of the entire rotor 1 or the reaction force acting on the rotor 1. The adjustment member 5 may be omitted.

[0055] Embodiment 2 Next, a rotating machine 100C according to a second embodiment will be described with reference to Fig. 6. Fig. 6 is a perspective view showing a configuration of a rotating machine 100C according to the second embodiment. This embodiment differs from the first embodiment in that the rotating machine 100C includes a plurality of support members 3. In the second embodiment, the same reference numerals are used for parts that overlap with the first embodiment, and description thereof will be omitted. For ease of understanding, Fig. 6 illustrates the rotating machine 100C as viewed from one side in the axial direction.

[0056] The rotating machine 100C includes three support members 3. In this embodiment, the shape of each support member 3 is cylindrical, but is not particularly limited as long as it can support the rotor 1. Hereinafter, when the three support members 3 are to be distinguished from one another, they will be referred to as support member 3A, support member 3B, and support member 3C. The three support members 3A, 3B, and 3C are arranged at a distance from one another in the circumferential direction. The three support members 3A, 3B, and 3C are arranged at equal angles in the circumferential direction. The three support members 3A, 3B, and 3C are arranged at 120 degree intervals in the circumferential direction. Each of the three support members 3A, 3B, and 3C supports the rotor 1. In other words, the rotor 1 is supported by the three support members 3A, 3B, and 3C that are arranged at a distance from one another in the circumferential direction.

[0057] Next, effects of the rotating machine 100C according to this embodiment will be described.

[0058] In this embodiment, the rotor 1 is supported by three support members 3A, 3B, and 3C that are spaced apart from each other in the circumferential direction. With this configuration, in this embodiment, the three support members 3A, 3B, and 3C generate support forces f21, f22, and f23 that support the rotor 1 in the axial direction and the tilt direction, respectively. Therefore, further displacement of the rotor 1 in the axial direction and the tilt direction are suppressed. This makes it possible to suppress vibration of the rotor 1 in the axial direction and the tilt direction. Note that the points of application of the support forces f21, f22, and f23 are preferably positioned at equal angles in the circumferential direction, and in this embodiment, they are positioned at 120 degree intervals in the circumferential direction. In this way, further displacement of the rotor 1 in the axial direction and the tilt direction can be further suppressed.

[0059] In this embodiment, as in the first embodiment, the rotor 1 is displaced vertically downward relative to the stator 2, and the rotor 1 is supported by the support member 3 at a position where it is sunk vertically downward relative to the stator 2. Therefore, the force supporting the gravity mg acting on the rotor 1 is the sum of the restoring force f1, which is the force with which the stator 2 magnetically attracts the rotor 1, and the supporting force f2, which is the sum of the supporting forces f21, f22, and f23, which are the forces with which the rotor 1 is supported in the axial direction by each of the support members 3A, 3B, and 3C. Since the supporting forces f21, f22, and f23 are equal to the remaining components of the gravity mg that cannot be supported by the restoring force f1, the following formula (3) is established. f21+f22+f23=mg-f1···(3)

[0060] Therefore, according to the above formula (3), the more the axial displacement z of the rotor 1 relative to the stator 2 is made negative and the larger its absolute value is, the more the restoring force f1 can be increased, and therefore the supporting force f2 can be reduced. This provides the same effect as the effect achieved by reducing the supporting force f2 described in paragraph 0036 above.

[0061] In this embodiment, the rotor 1 is supported by three support members 3A, 3B, and 3C that are spaced apart from each other in the circumferential direction. This configuration allows each of the support members 3A, 3B, and 3C to be made smaller and lighter than when a single support member 3 is used. Furthermore, when a defect occurs in one of the three support members 3A, 3B, and 3C, only the defective one needs to be replaced, which reduces the cost of replacement.

[0062] Next, a modification of the second embodiment will be described.

[0063] In this embodiment, the number of the support members 3 is three, but it may be four or more. That is, the rotor 1 in this embodiment may be supported by three or more support members 3 spaced apart from each other in the circumferential direction. If there is variation in the positions of the support members 3 in the axial direction, for example, a phenomenon may occur in which three of the four or more support members 3 support the rotor 1 and the remaining support members 3 do not support the rotor 1. Even if any of the support members 3 supporting the rotor 1 loses its support function due to wear or damage, if there are four or more support members 3, three or more support members 3 including the support member 3 that did not support the rotor 1 will newly support the rotor 1. This ensures redundancy of the support members 3 and improves the reliability of the rotating machine 100C.

[0064] Each of the three support members 3A, 3B, and 3C may have a low-friction portion that reduces the frictional force with the rotor 1, as in the first embodiment. In this way, the frictional force generated between the rotor 1 and the support members 3 can be reduced, and the same effect as that achieved by reducing the support force f2 described in paragraph 0036 above can be achieved.

[0065] Embodiment 3 Next, a rotating machine 100D according to a third embodiment will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing the configuration of a rotating machine 100D according to the third embodiment. This embodiment differs from the first and second embodiments in that the support member 3 functions as a hydrostatic bearing that supports the rotor 1. In the third embodiment, the same reference numerals are used for parts that overlap with the first and second embodiments, and descriptions thereof will be omitted.

[0066] The support member 3 is a single member. Inside the support member 3, a flow path 3b through which the fluid flows is formed. Reference numeral 8 in FIG. 7 shows a schematic representation of the flow of the fluid. The fluid may be a gas or a liquid. An example of the gas is air. An example of the liquid is water or oil. The shape of the support member 3 is, for example, a hollow disk shape, but is not particularly limited as long as the fluid can flow out toward the rotor 1. An inlet 3f is formed on the outer peripheral surface 3c of the support member 3 for allowing the fluid to flow into the flow path 3b. An outlet 3g is formed on the surface 3d of the support member 3 facing the rotor 1 for allowing the fluid to flow out from the flow path 3b toward the rotor 1. The outlet 3g has a circumferential shape extending in the circumferential direction. The fluid flowing out from the outlet 3g toward the rotor 1 supports the rotor 1 in the axial direction and the tilt direction. The fluid flowing out from the outlet 3g toward the rotor 1 supports the rotor 1 in a circumferential shape. In other words, the fluid flowing out from the outlet 3g toward the rotor 1 supports the rotor 1 over the entire circumference of the rotor 1. In this embodiment, the support member 3 functions as a hydrostatic bearing that supports the rotor 1.

[0067] Next, effects of the rotating machine 100D according to this embodiment will be described.

[0068] In this embodiment, a flow path 3b through which a fluid flows is formed inside the support member 3, and an outlet 3g for causing the fluid to flow out from the flow path 3b toward the rotor 1 is formed on a surface 3d of the support member 3 facing the rotor 1. With this configuration, further displacement of the rotor 1 in the axial direction and displacement of the rotor 1 in the tilt direction are suppressed. This makes it possible to suppress vibration of the rotor 1 in the axial direction and the tilt direction. In addition, with the above configuration, the support member 3 functions as a hydrostatic bearing that supports the rotor 1, so that the frictional force generated between the rotor 1 and the support member 3 can be further reduced.

[0069] In this embodiment, the rotor 1 is displaced vertically downward relative to the stator 2, and is supported by the support member 3 at a position where the rotor 1 is sunk vertically downward relative to the stator 2. With this configuration, a restoring force f1 is generated by the axial displacement z of the rotor 1, and the support force f2 can be reduced. This makes it possible to reduce the flow rate and pressure of the fluid flowing out from the outlet 3g toward the rotor 1. This makes it possible to reduce the input energy for preparing the fluid to flow from the inlet 3f into the flow path 3b of the support member 3, and also to reduce the torque loss caused by physical contact between the rotor 1 and the support member 3.

[0070] Next, a modification of the third embodiment will be described.

[0071] As shown in FIG. 8, the rotating machine 100E may include a plurality of support members 3. FIG. 8 is a cross-sectional view showing a configuration of the rotating machine 100E according to a modification of the third embodiment. Although FIG. 8 illustrates two support members 3, the rotating machine 100E actually includes three support members 3. FIG. 8 illustrates support forces f21 and f22 that support the rotor 1 in the axial direction and the tilt direction by each of the two support members 3A and 3B, but actually, a support force f23 (not shown) that supports the rotor 1 in the axial direction and the tilt direction by the remaining support member 3 (not shown) is also generated. The three support members 3 are arranged apart from each other in the circumferential direction. The three support members 3 are arranged at equal angles in the circumferential direction. The three support members 3 are arranged at intervals of 120 degrees in the circumferential direction.

[0072] A flow path 3b through which the fluid flows is formed inside each of the three support members 3. The shape of each support member 3 is, for example, a hollow cylinder, but is not particularly limited as long as the fluid can flow out toward the rotor 1. An inlet 3f is formed on a surface 3e of each support member 3 facing away from the rotor 1 to allow the fluid to flow into the flow path 3b. An outlet 3g is formed on a surface 3d of each support member 3 facing the rotor 1 to allow the fluid to flow out from the flow path 3b toward the rotor 1. The fluid flowing out from each outlet 3g of the three support members 3 toward the rotor 1 supports the rotor 1 in the axial direction and in the tilt direction. The fluid flowing out from each outlet 3g of the three support members 3 toward the rotor 1 supports the rotor 1 in a point-like manner. In other words, the rotor 1 is supported by the fluid flowing out from each outlet 3g of the three support members 3 that are separated from each other in the circumferential direction. In this modified example, each support member 3 also functions as a hydrostatic bearing that supports the rotor 1.

[0073] This modification can also achieve the same effects as those of the third embodiment. In this modification, the number of support members 3 is three, but it may be four or more. That is, the rotor 1 of this modification only needs to be supported by the fluid flowing out from each of the outlets 3g of three or more support members 3 that are spaced apart from each other in the circumferential direction.

[0074] Embodiment 4 Next, a rotating machine 100F according to a fourth embodiment will be described with reference to Fig. 9. Fig. 9 is a perspective view showing a configuration of a support member 3 of a rotating machine 100F according to the fourth embodiment. This embodiment differs from the first embodiment in that the support member 3 functions as a dynamic pressure bearing that supports the rotor 1. In the fourth embodiment, the same reference numerals are used for parts that overlap with the first embodiment, and description thereof will be omitted.

[0075] A surface 3d of the support member 3 facing the rotor 1 (not shown) is formed with a plurality of grooves 3h that open toward the rotor 1. The grooves 3h are arranged at a distance from each other in the circumferential direction. The grooves 3h are arranged at equal angles in the circumferential direction. The number of grooves 3h is five in this embodiment, but is not particularly limited. The grooves 3h are recessed toward the side opposite to the side where the rotor 1 is present in the axial direction. A flat portion 3i is formed between the grooves 3h adjacent to each other in the circumferential direction. The flat portion 3i is a flat portion perpendicular to the axial direction. The flat portion 3i is arranged closer to the rotor 1 than the grooves 3h in the axial direction. The grooves 3h and the flat portions 3i are arranged alternately in the circumferential direction.

[0076] The groove 3h has a first groove surface 3h1, a second groove surface 3h2, and a third groove surface 3h3. The first groove surface 3h1 is a surface extending in the axial direction. The first groove surface 3h1 is continuous with one of the two flat portions 3i adjacent to the groove 3h. The first groove surface 3h1 extends in the axial direction away from one of the flat portions 3i. The second groove surface 3h2 is a surface extending in the circumferential direction. The second groove surface 3h2 extends in the circumferential direction from an end portion of the first groove surface 3h1 opposite to an end portion continuing with one of the flat portions 3i. The third groove surface 3h3 is an inclined surface that is inclined so as to approach the rotor 1 as it extends in the circumferential direction away from the second groove surface 3h2. The third groove surface 3h3 is inclined with respect to the axial direction. The third groove surface 3h3 extends in the circumferential direction from an end portion of the second groove surface 3h2 opposite to an end portion continuing to the first groove surface 3h1. The end portion of the third groove surface 3h3 opposite to the end portion continuing to the second groove surface 3h2 continues to the other of the two flat portions 3i adjacent to the groove 3h.

[0077] Next, effects of the rotating machine 100F according to this embodiment will be described.

[0078] In this embodiment, a groove 3h that opens toward the rotor 1 is formed on the surface 3d of the support member 3 facing the rotor 1. With this configuration, when the rotor 1 rotates, the groove 3h eliminates the passage of the fluid, and the fluid flows from the support member 3 toward the rotor 1. Therefore, the pressure of the fluid flowing from the support member 3 toward the rotor 1 is generated. This allows the rotor 1 to rotate without physically contacting the support member 3. Therefore, it is possible to further reduce the frictional heat generated between the rotor 1 and the support member 3, and to reduce the torque loss caused by the physical contact between the rotor 1 and the support member 3. As shown in FIG. 9, it is preferable that the groove 3h has a third groove surface 3h3 that is an inclined surface inclined with respect to the axial direction. In this way, when the rotor 1 rotates, the inclination of the three-dimensional groove 3h eliminates the passage of the fluid, and the fluid easily flows from the support member 3 toward the rotor 1.

[0079] The phenomenon in which the rotor 1 and the support member 3 become physically out of contact occurs when the rotor 1 rotates. Therefore, when the rotor 1 is stationary, the support member 3 does not function as a dynamic pressure bearing that supports the rotor 1. However, when the rotor 1 is rotating, if the rotation speed of the rotor 1 exceeds a certain threshold, the support member 3 functions as a dynamic pressure bearing that supports the rotor 1.

[0080] In this embodiment, a part of the gravity mg acting on the rotor 1 is supported by the restoring force f1, so the remaining part of the gravity mg of the rotor 1 can be supported by the pressure of the fluid flowing from the support member 3 toward the rotor 1. This makes it possible to reduce the supporting force f2. Therefore, the threshold value of the rotation speed of the rotor 1 at which the rotor 1 and the support member 3 are not in physical contact with each other can be set low, and the support member 3 functions as a dynamic pressure bearing that supports the rotor 1 in a wide operating range of the rotating machine 100F.

[0081] In this embodiment, the inclination of the three-dimensional groove 3h can be reduced to reduce the pressure of the fluid flowing from the support member 3 toward the rotor 1. This can reduce the input energy of the fluid, thereby improving the operating efficiency of the entire rotating machine 100F.

[0082] Next, a modification of the fourth embodiment will be described.

[0083] As shown in FIG. 10, grooves 1e may be formed on the rotor 1. FIG. 10 is a diagram showing the configuration of the rotor 1 of a rotating machine 100G according to a modified example of the fourth embodiment, and is a diagram showing the rotor 1 viewed along the axial direction. In FIG. 10, the grooves 1e are hatched with dots for easy understanding. A surface 1d of the rotor 1 facing the support member 3 (not shown) is formed with a plurality of grooves 1e that open toward the support member 3. The plurality of grooves 1e are arranged apart from each other in the circumferential direction. The plurality of grooves 1e are arranged at equal angles in the circumferential direction. The number of grooves 1e is nine in this embodiment, but is not particularly limited. The grooves 1e are recessed toward the side opposite to the side where the support member 3 exists in the axial direction. A flat portion 1f is formed between the grooves 1e adjacent to each other in the circumferential direction. The flat portion 1f is a flat portion perpendicular to the axial direction. The flat portion 1f is arranged at a position closer to the support member 3 than the grooves 1e in the axial direction. The grooves 1e and the flat portions 1f are arranged alternately in the circumferential direction.

[0084] Each groove 1e extends in the radial direction and is formed from the outer peripheral surface to the inner peripheral surface of the rotor 1. Each groove 1e extends while bending so as to be located on one side of the circumferential direction as it moves from the outer side to the inner side in the radial direction. When the extension direction of each groove 1e is projected onto a plane normal to the rotation axis AX of the rotor 1, the extension direction of each groove 1e is disposed at a position shifted from the rotation axis AX of the rotor 1. The openings 1g of each groove 1e that open on the outer peripheral surface of the rotor 1 are disposed at equal angles apart in the circumferential direction. The openings 1h of each groove 1e that open on the inner peripheral surface of the rotor 1 are disposed at equal angles apart in the circumferential direction. The openings 1g and the openings 1h of each groove 1e are shifted from each other in the circumferential direction. The groove width D of each groove 1e narrows from the outer side to the inner side in the radial direction. In other words, the groove width D of each groove 1e is wider toward the outer side in the radial direction and narrower toward the inner side in the radial direction.

[0085] In this modification, when the rotor 1 rotates, the fluid flows into the groove 1e from the radially outer side, and as it flows radially inward within the groove 1e, it has nowhere to go and flows from the rotor 1 toward the support member 3. This generates pressure in the fluid flowing from the rotor 1 toward the support member 3, causing the rotor 1 to repel away from the support member 3 in the axial direction. This allows the rotor 1 to rotate without physical contact with the support member 3. This makes it possible to further reduce frictional heat generated between the rotor 1 and the support member 3, and also to reduce torque loss caused by the support member 3 coming into physical contact with the rotor 1.

[0086] The phenomenon in which the rotor 1 and the support member 3 are not physically in contact with each other occurs when the rotor 1 rotates. Therefore, when the rotor 1 is stationary, the support member 3 does not function as a dynamic pressure bearing that supports the rotor 1, but when the rotation speed of the rotor 1 exceeds a certain threshold value during rotation of the rotor 1, the support member 3 functions as a dynamic pressure bearing that supports the rotor 1. Note that a groove 3h having the same shape as the groove 1e shown in FIG. 10 may be formed on the surface 3d of the support member 3 facing the rotor 1 shown in FIG. 9, or a groove 1e having the same shape as the groove 3h shown in FIG. 9 may be formed on the surface 1d of the rotor 1 facing the support member 3 shown in FIG. 10. In addition, it is sufficient that the grooves 3h, 1e opening toward the other side are formed on either the surface 3d of the support member 3 facing the rotor 1 or the surface 1d of the rotor 1 facing the support member 3.

[0087] Embodiment 5. Next, a rotating machine 100H according to a fifth embodiment will be described with reference to Figs. 11 and 12. Fig. 11 is a perspective view showing a configuration of a part of a stator core 2a of a rotating machine 100H according to the fifth embodiment. Fig. 12 is a cross-sectional view showing a configuration of a rotating machine 100H according to the fifth embodiment, and is a diagram for explaining an axial force acting on a rotor 1. This embodiment differs from the first embodiment in that the permeance decreases in one direction from one side to the other in the axial direction. In the fifth embodiment, the same reference numerals are used for parts that overlap with the first embodiment, and description thereof will be omitted.

[0088] As shown in Figures 11 and 12, each tooth 2c has multiple tooth body parts 2e protruding radially inward from the back yoke part 2d, and multiple tooth tip parts 2f protruding in both circumferential directions from the tip of each tooth body part 2e. The shape of the tooth tip parts 2f is a brim shape that is wider than the circumferential width of the tooth body part 2e. This allows a large amount of magnetic flux 7c, 7d to pass between the stator 2 and the rotor 1 shown in Figure 12. The dashed line in Figure 12 shows the boundary between the tooth 2c and the back yoke part 2d.

[0089] As shown in FIG. 11, the number of the tooth main body 2e and the number of the tooth tip portion 2f in each tooth 2c are not particularly limited, but are two each in this embodiment. The two tooth main body portions 2e are stacked in the axial direction. The two tooth tip portions 2f are stacked in the axial direction. Hereinafter, the tooth main body portion 2e and the tooth tip portion 2f arranged on one side in the axial direction are referred to as the first tooth main body portion 2e1 and the first tooth tip portion 2f1, respectively, and the first tooth main body portion 2e1 and the first tooth tip portion 2f1 are collectively referred to as the first tooth portion 2c1. The tooth main body portion 2e and the tooth tip portion 2f arranged on the other side in the axial direction are referred to as the second tooth main body portion 2e2 and the second tooth tip portion 2f2, respectively, and the second tooth main body portion 2e2 and the second tooth tip portion 2f2 are collectively referred to as the second tooth portion 2c2. In the present embodiment, the first teeth 2c1 are disposed vertically above the second teeth 2c2.

[0090] The circumferential width W1 of the first teeth tip portion 2f1 is wider than the circumferential width W2 of the second teeth tip portion 2f2. That is, the circumferential width of the teeth tip portion 2f narrows in one direction from one side of the axial direction where the first teeth tip portion 2f1 exists to the other side of the axial direction where the second teeth tip portion 2f2 exists. The radial length L1 of the first teeth portion 2c1 is longer than the radial length L2 of the second teeth portion 2c2. That is, the radial length of the teeth 2c shortens in one direction from one side of the axial direction where the first teeth portion 2c1 exists to the other side of the axial direction where the second teeth portion 2c2 exists. As a result, the teeth 2c have a teeth length difference G, which is the difference between the radial length L1 of the first teeth portion 2c1 and the radial length L2 of the second teeth portion 2c2.

[0091] Here, permeance will be explained. Permeance means an amount that indicates the ease with which magnetic flux 7c, 7d passes through at least one of the gap portion 4 and the stator core 2a, which is an iron core, in a magnetic path that circulates around the stator 2 and the rotor 1 in the radial and circumferential directions. Generally speaking, magnetic flux passes through iron more easily than through air, so if the magnetic path is an iron core, the permeance is large. Also, the permeance increases as the width of the magnetic path increases, and increases as the magnetic path length of the air is shorter and the magnetic path length of the iron core is longer. In this embodiment, the circumferential width W1 of the first teeth tip portion 2f1 is wider than the circumferential width W2 of the second teeth tip portion 2f2, and the radial length L1 of the first teeth portion 2c1 is longer than the radial length L2 of the second teeth portion 2c2. Therefore, the permeance of the second teeth portion 2c2 is smaller than that of the first teeth portion 2c1. In other words, the permeance, which is a quantity that represents the ease with which magnetic flux 7c, 7d can pass through at least one of the gap portion 4 and the stator core 2a, which is the iron core, in the magnetic path that circles the stator 2 and the rotor 1 in the radial and circumferential directions, decreases in one direction from one side in the axial direction to the other.

[0092] Next, a description will be given of the axial force acting on the rotor 1. In FIG.

[0093] As shown in FIG. 12, the force that supports the gravity mg acting on the rotor 1 is the sum of the restoring force f1, which is the force with which the stator 2 magnetically attracts the rotor 1, and the supporting force f2, which is the force with which the support member 3 supports the rotor 1 in the axial direction. Here, since the rotor 1 is displaced in the axial direction relative to the stator 2 by the gravity mg, a magnetic flux 7d is generated that passes obliquely between the rotor 1 and the lower surface of the tip of the second teeth 2c2. Therefore, the restoring force f1 includes a restoring force f12 generated by the magnetic flux 7d. In addition, due to the difference between the circumferential width W1 of the first teeth tip 2f1 and the circumferential width W2 of the second teeth tip 2f2 and the teeth length difference G shown in FIG. 11, a magnetic flux 7c is also generated that passes obliquely between the rotor 1 and the part of the lower surface of the tip of the first teeth 2c1 that is exposed from the second teeth 2c2. Therefore, the restoring force f1 also includes the restoring force f11 generated by the magnetic flux 7c. As a result, the restoring force f1 is generated at a plurality of axial positions of the stator 2, and is the sum of the restoring forces f11 and f12. As a result, even if the axial displacement z of the rotor 1 is the same as in the first embodiment, in this embodiment, the restoring force f1 increases by the amount of the restoring force f11 compared to the first embodiment, and the supporting force f2 decreases by the amount of the increase in the restoring force f1. Therefore, the following formula (4) is established. f2=mg-f11-f12···(4)

[0094] Next, the effects of the rotating machine 100H according to this embodiment will be described.

[0095] In this embodiment, the permeance, which is a quantity representing the ease with which the magnetic fluxes 7c, 7d pass through at least one of the gap portion 4 and the stator core 2a, which is an iron core, in the magnetic path that goes around the stator 2 and the rotor 1 in the radial and circumferential directions, decreases in one direction from one side in the axial direction to the other. With this configuration, it is possible to increase the restoring force f1 in one direction from the other side to one side in the axial direction. Therefore, it is possible to further reduce the frictional heat generated between the rotor 1 and the support member 3, and to reduce the torque loss generated by the support member 3 physically contacting the rotor 1. This makes it possible to further extend the life of the support member 3, and further improve the operating efficiency of the entire rotating machine 100H.

[0096] In this embodiment, the generation of the restoring force f11 means that, when the supporting force f2 is constant, the axial displacement z of the rotor 1 can be brought closer to 0. As the axial displacement z of the rotor 1 approaches 0, the area in which the rotor 1 and the stator 2 face each other in the radial direction increases, and the supporting force and torque in the radial direction (XY axis directions) increase. This reduces the current required to generate the same supporting force and the same torque in the radial direction (XY axis directions), improving the operating efficiency of the entire rotating machine 100H.

[0097] Next, a modification of the fifth embodiment will be described.

[0098] In the present embodiment, both the circumferential width and the radial length of the first teeth 2c1 and the second teeth 2c2 are changed, but only one of them may be changed. Also, in the present embodiment, the circumferential width and the radial length of the first teeth 2c1 and the second teeth 2c2 are changed, but only one of the circumferential width and the radial length of the three or more teeth may be changed.

[0099] The support member 3 of this embodiment may be modified to a configuration that functions as a hydrostatic bearing that supports the rotor 1 as in the above-described embodiment 3, or may be modified to a configuration that functions as a hydrodynamic bearing that supports the rotor 1 as in the above-described embodiment 4. In this embodiment, by increasing the restoring force f1, it is possible to further reduce the fluid pressure required when the support member 3 functions as a hydrostatic bearing or a hydrodynamic bearing.

[0100] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0101] 1 rotor, 1a rotor core, 1b permanent magnet, 1c through hole, 1d, 3d, 3e surface, 1e, 3h groove, 1f, 3i flat portion, 1g, 1h opening, 2 stator, 2a stator core, 2b, 2b1, 2b2 winding, 2c teeth, 2c1 first teeth portion, 2c2 second teeth portion, 2d back yoke portion, 2e teeth main body portion, 2e1 first teeth main body portion, 2e2 second teeth main body portion, 2f teeth tip portion, 2f1 first teeth tip portion, 2f2 second teeth tip portion, 3, 3A, 3B, 3C support member, 3a support surface, 3b flow path, 3c outer peripheral surface, 3f inlet, 3g outlet, 3h1 first groove surface, 3h2 second groove surface, 3h3 third groove surface, 4 gap portion, 5 adjustment member, 6 frame, 6a peripheral wall portion, 6b shaft end wall, 6c hole, 7a, 7b, 7c, 7d magnetic flux, 8 fluid flow, 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H rotating machine, AX rotating shaft.

Claims

1. a rotor that rotates around a rotation axis; a stator disposed on an outer periphery or an inner periphery of the rotor, separated from the rotor by a gap; a support member disposed on at least one side of the rotor in the axial direction along the rotation axis, and supporting the rotor so as to limit displacement of the rotor in the axial direction and the tilt direction; Equipped with At least one of the rotor and the stator has an iron core, At least the other of the rotor and the stator has a magnetic force generating member, the iron core and the magnetic force generating member are arranged so that the stator restores displacement of the rotor in the axial direction and in the tilt direction by a force that magnetically attracts the rotor, the rotor is supported by the support member at a position displaced in the axial direction relative to the stator, the axial direction and tilt direction of the rotor are passively stabilized by the force of the stator magnetically attracting the rotor in a non-contact manner and by the support member that supports the rotor; A rotating machine characterized in that the radial direction of the rotor is actively stabilized by a radial support force that supports the rotor without contact with the stator, the radial support force being generated by passing current through the windings of the stator.

2. A rotor that rotates around a rotation axis; a stator disposed on an outer periphery or an inner periphery of the rotor, separated from the rotor by a gap; a support member disposed on at least one side of the rotor in the axial direction along the rotation axis, and supporting the rotor so as to limit displacement of the rotor in the axial direction and the tilt direction; Equipped with At least one of the rotor and the stator has an iron core, At least the other of the rotor and the stator has a magnetic force generating member, the iron core and the magnetic force generating member are arranged so that the stator restores displacement of the rotor in the axial direction and in the tilt direction by a force that magnetically attracts the rotor, the rotor is supported by the support member at a position where it is displaced in the axial direction relative to the stator and a surface that does not face the stator is provided on only one side of the outer peripheral surface or the inner peripheral surface of the rotor that faces the gap portion, and when a position of the stator in the axial direction is taken as a reference position, the support member supports the rotor at a position where the rotor is displaced from the reference position in the axial direction in a direction of gravity acting on the rotor or in a direction in which a reaction force acting on the rotor during rotation is generated, the supporting force generated by the support member is reduced by the burden of an axial restoring force that is magnetically generated in a non-contact manner between the stator and the rotor, compared to when the rotor is supported at a position where it is not displaced in the axial direction from the reference position; A rotating machine characterized in that the radial direction of the rotor is actively stabilized by a radial support force that supports the rotor without contact with the stator, the radial support force being generated by passing current through the windings of the stator.

3. the support member is in circumferential contact with the rotor, 3. The rotating machine according to claim 1, wherein the support member includes a low-friction portion that reduces friction between the support member and the rotor.

4. 3. The rotating machine according to claim 1, wherein the rotor is supported by three or more of the support members spaced apart from one another in the circumferential direction.

5. an axial direction along the rotation axis is parallel to the vertical direction, 3. The rotating machine according to claim 1, wherein the support member is disposed vertically below the rotor.

6. when a position of the stator in the axial direction is taken as a reference position, the support member supports the rotor at a position where the rotor is displaced from the reference position in the axial direction in a direction of gravity acting on the rotor or in a direction in which a reaction force acting on the rotor during rotation is generated, 2. The rotating machine according to claim 1, wherein the supporting force generated by the support member is reduced due to the burden of an axial restoring force generated between the stator and the rotor, compared to when the rotor is supported at a position where it is not displaced axially from the reference position.

7. 3. The rotating machine according to claim 1, further comprising an adjustment member that adjusts the position of the support member in the axial direction.

8. A flow path through which a fluid flows is formed inside the support member, 3. The rotating machine according to claim 1, wherein an outlet for discharging the fluid from the flow path toward the rotor is formed on a surface of the support member facing the rotor.

9. 3. The rotating machine according to claim 1, wherein a groove opening toward the other surface of the support member facing the rotor or a surface of the rotor facing the support member is formed in either one of the surface of the support member facing the rotor or the surface of the rotor facing the support member.

10. 3. The rotating machine according to claim 1, wherein a permeance, which is a quantity representing the ease with which magnetic flux passes through at least one of the gap portion and the iron core in a magnetic path that circulates around the stator and the rotor in both radial and circumferential directions, decreases in one direction from one end of the axial direction to the other end.

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