JP7666178B2 - Rotating Electric Machine - Google Patents

Description

The present invention relates to a rotating electric machine.

Patent Document 1 discloses a rotating electric machine with a magnetic flux variable mechanism. This rotating electric machine is equipped with a magnetic flux variable mechanism on the axial end face of the rotor core. The magnetic flux variable mechanism uses centrifugal force to bring the magnetic flux short-circuit material closer to the permanent magnet, reducing the magnetic flux that links with the stator coil when the rotor rotates at a high rotational speed. As a result, the back electromotive voltage generated by the magnetic flux linkage is prevented from becoming excessive.

JP 2019-97359 A

In a rotating electric machine with a magnet placed on the rotor, an induced voltage is generated in the stator coil as the rotor rotates inside the stator. The induced voltage increases as the rotor rotation speed increases. For this reason, it is common to pass a field-weakening current through the stator coil to suppress the induced voltage. However, passing a field-weakening current increases copper loss, which may reduce the efficiency of the rotating electric machine.

The present invention was made in consideration of these problems, and aims to suppress induced voltage during high speed rotation and improve efficiency.

A rotating electric machine according to the present invention is a rotating electric machine having a rotor and a stator, with a magnet disposed on the rotor, and a movable mechanism that changes the magnetic flux to the stator by moving the magnet in accordance with the rotation speed of the rotor. The movable mechanism according to one aspect of the present invention is a mechanism that reduces the magnetic flux to the stator by moving the magnet in a direction away from the stator, and includes a weight that moves the magnet by moving by centrifugal force, and a housing frame that is assembled to the rotor by being pushed into an insertion hole provided in the rotor. The weights are provided on both sides of the magnet in the circumferential direction, and each has an opposing inclined surface that extends obliquely radially outward from both sides of the magnet in the circumferential direction toward the center when viewed along the axial direction. The movable mechanism further includes a support member that is connected to the magnet and abuts each of the opposing inclined surfaces when the magnet is in its original position.
According to another aspect of the present invention, the movable mechanism is a mechanism for reducing the magnetic flux to the stator by moving the magnet in a direction away from the stator, and includes a weight that moves the magnet by centrifugal force. The rotor includes a plurality of magnets per magnetic pole. The magnet is disposed on the q-axis located at the boundary between adjacent magnetic poles in the circumferential direction formed on the rotor by the plurality of magnets, and moves along the radial direction.

According to this aspect, the magnet flux to the stator can be changed by, for example, changing the distance between the magnet and the stator by moving the magnet with the movable mechanism according to the rotation speed of the rotor. Therefore, by moving the magnet with the movable mechanism, it is possible to reduce the interlinkage flux to the stator at high rotation speeds and suppress the induced voltage. In addition, since the field weakening current can be suppressed by the amount of the suppression of the induced voltage, copper loss can be reduced, and this makes it possible to improve the efficiency of the rotating electric machine. Furthermore, since the movable mechanism moves the magnet placed in the rotor, the reduction range of the interlinkage flux is not concentrated at the axial end of the rotating electric machine as in the case where a magnetic flux variable mechanism is provided on the axial end face of the rotor core, and the axial length of the rotating electric machine is not lengthened. In addition, since the interlinkage flux to the stator can be increased by returning the magnet to its original position with the movable mechanism at low rotation speeds, it is also possible to ensure torque at low rotation speeds.

FIG. 2 is a diagram showing a main part of a rotating electric machine. 11A and 11B are diagrams illustrating the state of the movable mechanism during low rotation. 11A and 11B are diagrams illustrating a state of the movable mechanism during high speed rotation. FIG. 4 is an explanatory diagram of an acting force in a movable mechanism. 6A and 6B are diagrams illustrating the action of the second permanent magnet during low rotation. 6A and 6B are diagrams illustrating the action of the second permanent magnet during high speed rotation. FIG. 4 is a diagram showing an example of magnetic flux density at low rotation speed. FIG. 4 is a diagram showing an example of magnetic flux density during high speed rotation.

The following describes an embodiment of the present invention with reference to the attached drawings.

Figure 1 is a diagram showing the main parts of a rotating electric machine 1. Figure 1 shows the main parts of the rotating electric machine 1 as viewed along the axial direction. Figure 1 shows the state of the rotating electric machine 1 at high speed. The rotating electric machine 1 includes a rotor 2, a first permanent magnet 3, a stator 4, and a movable mechanism 10. The rotating electric machine 1 is a magnet-embedded type rotating electric machine in which the first permanent magnet 3 is embedded in the rotor 2, and is considered to be an inner rotor structure rotating electric machine. The rotor 2 is a rotor core and has a ring-shaped shape. The rotor 2 is formed, for example, by laminating a large number of thin electromagnetic steel plates. The rotor 2 is provided with a magnet insertion hole, and the first permanent magnet 3 is arranged in the magnet insertion hole. The first permanent magnet 3 is formed of a bar magnet whose cross section perpendicular to the axial direction is rectangular, and the rotor 2 includes a plurality of first permanent magnets 3 per magnetic pole. The plurality of first permanent magnets 3 corresponds to a plurality of magnets and forms magnetic poles in the rotor 2. In FIG. 1, the first magnet 31 and the second magnet 32 form magnetic poles as a plurality of first permanent magnets 3, and the third magnet 33 and the fourth magnet 34 form magnetic poles as a plurality of first permanent magnets 3. The first permanent magnets 3 are arranged extending obliquely with respect to the q-axis when viewed along the axial direction. The q-axis is located at the boundary between magnetic poles adjacent to each other in the circumferential direction and extends along the radial direction. The magnetization directions of the first permanent magnets 3 are opposite to each other for magnetic poles adjacent to each other in the circumferential direction. For example, when the first magnet 31 and the second magnet 32 are magnetized so that the polarity on the outer periphery side is the N-pole, the third magnet 33 and the fourth magnet 34 are magnetized so that the polarity on the outer periphery side is the S-pole. The first permanent magnets 3 can be rare earth magnets such as neodymium magnets and samarium cobalt magnets, as well as ferrite magnets and alnico magnets. The stator 4, which is a stator core, has a ring-like shape and houses the rotor 2. The stator 4 is formed by stacking a large number of thin electromagnetic steel plates, for example. The stator 4 has multiple teeth 41 that protrude radially inward, and the stator coil is wound around the teeth 41.

The movable mechanism 10 includes a housing frame 11, a second permanent magnet 12, a support member 13, a weight 14, a weight spring 15, and a magnet spring 16. The movable mechanism 10 is disposed on the rotor 2. The rotor 2 is provided with an insertion hole for the movable mechanism 10, and the housing frame 11 is pushed into the insertion hole together with the movable mechanism 10 to be assembled to the rotor 2. The housing frame 11 has an inverted Y-shaped cylindrical shape with the radially outer side on the upper side when viewed along the axial direction, and forms an internal space that serves as a flux barrier (magnetic barrier). The part of the housing frame 11 that extends along the radial direction is disposed on the q-axis. This part forms a rectangular internal space (hereinafter referred to as a rectangular space) that is long in the radial direction when viewed along the axial direction. The second permanent magnet 12 is disposed in the rectangular space. The part of the housing frame 11 that is connected from the radially outer side to the forming part of the rectangular space forms an outer space whose width is narrowed at the connection part with the forming part on the radially outer side of the connection part. In the outer space, the magnet spring 16 is connected to the housing frame 11 from the radially inner side. The movable mechanism 10 has an outer flux barrier (magnetic barrier) B1 radially outward from the second permanent magnet 12. The outer flux barrier B1 is formed by at least the outer space of the outer space and the rectangular space. The outer flux barrier B1 is formed adjacent to the second permanent magnet 12.

The portion of the housing frame 11 that is connected from the radial inside to the rectangular space forming portion forms a deformed fan-shaped internal space (referred to as the deformed fan space) that is connected to the rectangular space at the circumferential center. The support member 13, the weight 14, and the weight spring 15 are arranged in the deformed fan space. The deformed fan space is formed symmetrically with respect to the q axis when viewed along the axial direction, and the inner flux barrier B2 on the radially inner side of the movable mechanism 10 is formed in the deformed fan space. The deformed fan space is formed so as to be convex toward the radially outer side when viewed along the axial direction, and the outer peripheral wall surface that defines the deformed fan space is composed of a flat surface rather than a curved surface. The flat surface is the guide slope 111 of the weight 14. The guide slope 111 is composed of the first guide slope 111a and the second guide slope 111b that extend obliquely radially outward in a direction from both sides of the second permanent magnet 12 in the circumferential direction toward the center when viewed along the axial direction, that is, in a direction toward the second permanent magnet 12 while being perpendicular to the q axis. The first guide slope 111a is provided on one circumferential side of the q axis, and the second guide slope 111b is provided on the other circumferential side of the q axis. When viewed along the axial direction, the acute angle formed by the first guide slope 111a and the q axis, and the acute angle formed by the second guide slope 111b and the q axis are set to, for example, 60°. The housing frame 11 is made of a non-magnetic material such as resin or metal.

The second permanent magnet 12 is disposed on the q-axis. The second permanent magnet 12 extends along the q-axis and is provided so as to be movable along the q-axis. The same magnet as the first permanent magnet 3 can be used for the second permanent magnet 12. The support member 13 is connected to the second permanent magnet 12 from the radially inner side. When viewed along the axial direction, the support member 13 has an inverted Y-shape with the radially outer side on the upper side. When viewed along the axial direction, the support member 13 branches and extends along the extension direction of the first guide slope 111a and the second guide slope 111b and the radial direction. The part of the support member 13 that extends along the radial direction is disposed on the q-axis and connects to the second permanent magnet 12. The parts of the support member 13 that extend along the first guide slope 111a and the second guide slope 111b are disposed symmetrically with respect to the q-axis. The part of the support member 13 that extends along the first guide slope 111a has a first tip portion 13a and a first opposing surface 13c. The first opposing surface 13c faces the first guide slope 111a. The portion of the support member 13 that extends along the second guide slope 111b has a second tip portion 13b and a second opposing surface 13d. The second opposing surface 13d faces the second guide slope 111b. The support member 13 is made of a non-magnetic material such as non-magnetic stainless steel.

The weight 14 is provided so as to be movable in the modified sector space. A non-magnetic material such as non-magnetic tungsten is used for the weight 14. A weight spring 15 is attached to the weight 14. The weight 14 is composed of a first weight 141 and a second weight 142 arranged on both circumferential sides of the second permanent magnet 12 when viewed along the axial direction. The weight spring 15 is composed of a first weight spring 151 and a second weight spring 152 arranged on both circumferential sides of the second permanent magnet 12 when viewed along the axial direction. The first weight 141 and the second weight 142 are configured similarly to each other, and the first weight spring 151 and the second weight spring 152 are also configured similarly to each other. For this reason, the following mainly describes the first weight 141 and the first weight spring 151 arranged on one circumferential side of the q-axis.

The first weight 141 is disposed between the first guide slope 111a and the first opposing surface 13c during high speed rotation and abuts against the first guide slope 111a. The first weight 141 is further abutted against the first opposing surface 13c. When viewed along the axial direction, the first weight 141 has a surface along each of the first opposing surface 13c, the first guide slope 111a, and the side surface on one circumferential side of the housing frame 11 that forms the deformed sector space. The first weight 141 has the following surface on the q-axis side. That is, when viewed along the axial direction, the first weight 141 has a slope that extends obliquely radially outward in a direction from one circumferential side of the second permanent magnet 12 toward the q-axis. The slope faces the second opposing slope 142a of the second weight 142 as the first opposing slope 141a. In other words, the first weight 141 and the second weight 142 have a first opposing inclined surface 141a and a second opposing inclined surface 142a, which are opposing inclined surfaces that extend obliquely radially outward in a direction from both sides in the circumferential direction of the second permanent magnet 12 toward the center when viewed along the axial direction. The first opposing inclined surface 141a and the second opposing inclined surface 142a enable the support member 13 to support the weight 14 during low rotation, which will be described later. When the first weight 141 is in contact with the first guide inclined surface 111a, the acute angle formed by the first opposing inclined surface 141a and the q axis when viewed along the axial direction is set to a very small angle (for example, a few degrees). The same is true for the second opposing inclined surface 142a.

The first weight spring 151 is, for example, a coil spring, and is attached to the first weight 141. The first weight spring 151 is disposed between the first weight 141 and a side surface of the housing frame 11 on one circumferential side that forms the deformed sector space. The first weight spring 151 connects the housing frame 11 and the first weight 141 by connecting them. When viewed along the axial direction, the first weight spring 151 exerts a spring force along the extension direction of the first guide slope 111a. The first weight spring 151 exerts a spring force along a direction perpendicular to the axial direction. The first weight spring 151 is arranged so that it is in a stretched state during high speed rotation, that is, in a state where it is extended from its natural length.

The magnet spring 16 is, for example, a coil spring, and is attached to the second permanent magnet 12. The magnet spring 16 is disposed radially outside the second permanent magnet 12. The magnet spring 16 is disposed on the q-axis. The magnet spring 16 connects the outer peripheral surface of the portion of the housing frame 11 that forms the outer space to the second permanent magnet 12, thereby connecting the housing frame 11 and the second permanent magnet 12. When viewed along the axial direction, the magnet spring 16 exerts a spring force along the q-axis. The magnet spring 16 exerts a spring force along a direction perpendicular to the axial direction. The magnet spring 16 is disposed so as to be in a tensioned state during high speed rotation.

Figure 2A is a diagram showing the state of the movable mechanism 10 at low rotation. Figure 2B is a diagram showing the state of the movable mechanism 10 at high rotation. At low rotation, the first rotation speed is reached, and at high rotation, the second rotation speed is reached, at which the rotating electric machine 1 rotates at a higher speed than the first rotation speed. At low rotation, the second permanent magnet 12 is located in a retracted position on the radially outer side as shown in Figure 2A. The retracted position is the original position, and at the retracted position, the second permanent magnet 12 abuts against the housing frame 11 from the radially inner side and is accommodated in a rectangular space. At the retracted position, the support member 13 abuts against the first opposing inclined surface 141a and the second opposing inclined surface 142a at the first tip portion 13a and the second tip portion 13b. When the second permanent magnet 12 is in the retracted position, the weight spring 15 does not generate a pulling force, and the first tip 13a and the second tip 13b abut against the first opposing inclined surface 141a and the second opposing inclined surface 142a due to a force acting radially outward on the second permanent magnet 12 and the support member 13. Therefore, the support member 13 supports the weight 14 by a force acting radially outward on the second permanent magnet 12 and the support member 13 during low rotation. As a result, the weight 14 is maintained in abutment against the guide inclined surface 111 even during low rotation.

When the rotation speed of the rotating electric machine 1 increases, the centrifugal force increases. As a result, the weight 14 moves radially outward along the guide slope 111 while pushing the support member 13 radially inward. This causes the second permanent magnet 12 to move radially inward together with the support member 13, that is, in a direction away from the stator 4. The second permanent magnet 12 moves in a direction away from the stator 4 at the portion facing it with the outer flux barrier B1 in between. The radial length of the outer flux barrier B1 changes in response to the movement of the second permanent magnet 12, and the radial length increases when the second permanent magnet 12 moves radially inward. The radial length corresponds to the length in the direction connecting the second permanent magnet 12 and the stator 4.

When the weight 14 moves radially outward to a certain extent, the contact portion of the support member 13 with the weight 14 changes from the first tip 13a and the second tip 13b to the first opposing surface 13c and the second opposing surface 13d. When the support member 13 is in contact with the weight 14 at the first opposing surface 13c and the second opposing surface 13d, the support member 13 does not move even if the weight 14 moves. As a result, the second permanent magnet 12 is positioned in the forward position on the radial inside as shown in FIG. 2B. The weight 14 can move radially outward until it contacts the second permanent magnet 12. The housing frame 11 may be provided with a stopper against which the weight 14 contacts when the second permanent magnet 12 is positioned in the forward position, and which restricts the weight 14 from moving radially outward.

Figure 3 is an explanatory diagram of the forces acting on the movable mechanism 10. When the rotating electric machine 1 is in operation, a centrifugal force F1 and an adhesive force F2 act on the second permanent magnet 12 in the radially outward direction. A centrifugal force F3 acts on the support member 13 in the radially outward direction, and a centrifugal force F4 acts on the weight 14 in the radially outward direction. The centrifugal force F4 of the weight 14 is composed of a first centrifugal force F41 acting on the first weight 141 and a second centrifugal force F42 acting on the second weight 142. The centrifugal force F1 and adhesive force F2 of the second permanent magnet 12 and the centrifugal force F3 of the support member 13 constitute a magnet-side resultant force, which acts against the centrifugal force F4 of the weight 14 when the second permanent magnet 12 is moved radially inward. For this reason, the mass of the weight 14 is set to a mass at which the centrifugal force F4 is greater than the magnet side resultant force when transitioning from low rotation to high rotation, i.e., at high rotation. As a result, the centrifugal force F4 of the weight 14 overcomes the magnet side resultant force when transitioning from low rotation to high rotation, making it possible to position the second permanent magnet 12 in a radially inward forward position at high rotation.

Furthermore, in this embodiment, the radial component F5 of the spring force of the weight spring 15 (the radial component F51 of the spring force of the first weight spring 151 and the radial component F52 of the spring force of the second weight spring 152) and the spring force F6 of the magnet spring 16 also act as forces that resist the centrifugal force F4 of the weight 14 when moving the second permanent magnet 12 radially inward. For this reason, the mass of the weight 14 is set to a mass that is greater than the magnitude of the radial component F5 and the magnitude of the spring force F6 in addition to the centrifugal force F4 at high rotation speeds. As a result, even when the weight spring 15 and the magnet spring 16 are generating a pulling force at high rotation speeds, the second permanent magnet 12 can be positioned in a forward position radially inward.

When the rotation speed of the rotating electric machine 1 is changed from high to low, the centrifugal force F4 of the weight 14 is decreased in accordance with the decrease in the rotation speed of the rotating electric machine 1. As a result, the weight spring 15 starts to move the weight 14 toward the retracted position radially outward against the centrifugal force F4, and the second permanent magnet 12 finally returns to the retracted position. When the rotation speed is changed from high to low and at low rotation, the support member 13 supports the weight 14 using the spring force F6 of the magnet spring 16. Therefore, when the rotation speed is changed from high to low, the weight 14 moves toward the radial inside while being supported by the support member 13. The movable mechanism 10 changes the magnetic flux to the stator 4 by moving the second permanent magnet 12 in accordance with the rotation speed of the rotor 2, as described below.

Figure 4A is a diagram explaining the action of the second permanent magnet 12 at low rotation. Figure 4B is a diagram explaining the action of the second permanent magnet 12 at high rotation. In Figures 4A and 4B, the arrangement and shape are appropriately simplified. As shown in Figures 4A and 4B, the second permanent magnet 12 forms a magnetic flux from the inside to the outside in the radial direction. As shown in Figure 4A, when the second permanent magnet 12 is located in a retracted position on the radial outside, the radial length of the outer flux barrier B1 is shortened by the amount that the second permanent magnet 12 is closer to the stator 4. In other words, the air gap between the second permanent magnet 12 and the stator 4 is reduced. As a result, in this case, the magnetic resistance is reduced, and the magnetic flux to the stator 4 is increased accordingly, so that the interlinkage magnetic flux to the stator 4 is increased. As shown in Figure 4B, when the second permanent magnet 12 is located in a forward position on the radial inside, the radial length of the outer flux barrier B1 is longer by the amount that the second permanent magnet 12 is farther from the stator 4. In other words, the outer flux barrier B1 becomes longer in the radial direction as the second permanent magnet 12 moves radially inward, which increases the air gap between the second permanent magnet 12 and the stator 4. As a result, in this case, not only does the second permanent magnet 12 move away from the stator 4, but the magnetic resistance increases, so the magnetic flux to the stator 4 decreases. As a result, the interlinkage magnetic flux to the stator 4 decreases, and the induced voltage is suppressed. In addition, in this case, the weakening field current can be suppressed by the amount that the induced voltage is suppressed, so copper loss can be reduced and the efficiency of the rotating electric machine 1 is improved.

5A is a diagram showing an example of magnetic flux density in the present embodiment. FIG. 5B is a diagram showing an example of magnetic flux density in the comparative example. In the comparative example, the movable mechanism 10 is not provided, and the second permanent magnet 12 is located in the retracted position regardless of the rotation speed of the rotating electric machine 1. FIGS. 5A and 5B show the magnetic flux density in the periphery of the retracted position of the second permanent magnet 12 at high rotation. In the present embodiment shown in FIG. 5A, the second permanent magnet 12 is located in the radially inner advanced position at high rotation, and is not located in the retracted position. As a result, in the present embodiment, the magnetic flux density is reduced in the region R of the stator 4 compared to the comparative example shown in FIG. 5B. In other words, in the present embodiment, the second permanent magnet 12 is not located in the retracted position at high rotation, so the radial length of the outer flux barrier B1 is longer than in the comparative example. As a result, in the present embodiment, the interlinkage magnetic flux to the stator 4 can be reduced more than in the comparative example at high rotation.

Next, we will explain the main effects of this embodiment.

The rotating electric machine 1 has a rotor 2 and a stator 4, and a second permanent magnet 12 is arranged on the rotor 2. The rotating electric machine 1 has a movable mechanism 10 that changes the magnetic flux to the stator 4 by moving the second permanent magnet 12 according to the rotation speed of the rotor 2. According to this configuration, by moving the second permanent magnet 12 with the movable mechanism 10, for example, the distance from the stator 4 can be changed to change the magnetic flux to the stator 4. Therefore, by moving the second permanent magnet 12 with the movable mechanism 10, it is possible to reduce the interlinkage magnetic flux to the stator 4 at high rotation speeds and suppress the induced voltage. In addition, at this time, the field weakening current can be suppressed by the amount of the suppression of the induced voltage, so copper loss can be reduced, and the efficiency of the rotating electric machine can be improved. Furthermore, since the movable mechanism 10 moves the second permanent magnet 12 arranged on the rotor 2, the range of reduction in interlinkage magnetic flux does not concentrate on the axial end of the rotating electric machine 1 as in the case where a magnetic flux variable mechanism is provided on the axial end face of the rotor core, and the axial length of the rotating electric machine 1 does not become long. In addition, by returning the second permanent magnet 12 to the retracted position using the movable mechanism 10 during low speed rotation, it is possible to increase the magnetic flux linkage to the stator 4, making it possible to ensure torque during low speed rotation.

In this embodiment, the movable mechanism 10 is a mechanism that reduces the magnetic flux to the stator 4 by moving the second permanent magnet 12 radially inward. With this configuration, it is possible to move the second permanent magnet 12 away from the stator 4 during high rotation, so that it is possible to reduce the interlinkage magnetic flux to the stator 4 during high rotation.

In this embodiment, the movable mechanism 10 has an outer flux barrier B1 radially outward from the second permanent magnet 12. The outer flux barrier B1 has a longer radial length as the second permanent magnet 12 moves radially inward. With this configuration, the outer flux barrier B1 can reduce the magnetic flux to the stator 4 at high rotation speeds, thereby reducing the flux linkage to the stator 4 at high rotation speeds.

In this embodiment, the movable mechanism 10 includes a weight 14 that moves the second permanent magnet 12 by being moved by centrifugal force F4. With this configuration, the second permanent magnet 12 is subjected to centrifugal force acting radially outward, i.e., toward the stator 4, and it is possible to move the second permanent magnet 12 radially inward using the weight 14 when transitioning from low rotation to high rotation. In addition, since the centrifugal force of the weight 14 is utilized, it is advantageous in terms of simplifying the configuration and reducing costs.

In this embodiment, the movable mechanism 10 further includes a weight spring 15 attached to the weight 14, and the weight spring 15 is compressed by the spring force of the weight spring 15 when the second permanent magnet 12 returns to the retracted position. With this configuration, the spring force of the weight spring 15 can be used to return the second permanent magnet 12 to the retracted position when transitioning from high rotation to low rotation.

In this embodiment, the movable mechanism 10 further includes a housing frame 11 that is assembled to the rotor 2 by being pushed into an insertion hole provided in the rotor 2. With this configuration, the housing frame 11 can be assembled to the rotor 2 by pushing the movable mechanism 10 together with the rotor 2, improving the ease of assembly of the movable mechanism 10.

In this embodiment, the weight 14 is a first weight 141 and a second weight 142, which are weights provided on both sides of the second permanent magnet 12 in the circumferential direction. The first weight 141 and the second weight 142 have a first opposing slope 141a and a second opposing slope 142a, which are opposing slopes that extend obliquely radially outward from both sides of the circumferential direction of the second permanent magnet 12 toward the center when viewed along the axial direction. The movable mechanism 10 further includes a support member 13 that is connected to the second permanent magnet 12 and abuts against the first opposing slope 141a and the second opposing slope 142a when the second permanent magnet is in the retracted position. With this configuration, the support member 13 abutting against the first opposing slope 141a and the second opposing slope 142a supports the weight 14 during low rotation, and a structure that allows the weight 14 to be appropriately positioned is obtained.

In this embodiment, the housing frame 11 extends obliquely from both sides of the second permanent magnet 12 in the circumferential direction toward the center in the radial direction and has a first guide slope 111a and a second guide slope 111b, which are guide slopes that guide the first weight 141 and the second weight 142, when viewed along the axial direction. The support member 13 branches and extends along the extension direction of the first guide slope 111a and the second guide slope 111b and the radial direction when viewed along the axial direction. The support member 13 is connected to the second permanent magnet 12 at a portion that branches and extends along the radial direction. When the second permanent magnet 12 is in the retracted position, the support member 13 abuts against the first opposing slope 141a and the second opposing slope 142a at the first tip portion 13a and the second tip portion 13b, which are the tip portions of the portion that branches and extends along the extension direction of the first guide slope 111a and the second guide slope 111b, respectively. The first weight 141 and the second weight 142 move radially outward along the corresponding guide slope 111 of the first guide slope 111a and the second guide slope 111b due to centrifugal force, moving the support member 13 radially inward, thereby moving the second permanent magnet 12 radially inward.

According to this configuration, when the rotation speed changes from low to high, the weight 14 is guided by the guide slope 111 and moved radially outward in response to an increase in the centrifugal force F4, thereby obtaining a structure capable of moving the second permanent magnet 12 radially inward. Furthermore, when the rotation speed changes from high to low, the weight 14 is supported by the support member 13 and moved radially inward in response to a decrease in the centrifugal force F4, thereby obtaining a structure capable of moving the second permanent magnet 12 radially outward. Furthermore, when the rotation speed changes from low to high, the weight 14 is supported by the support member 13, whose first end portion 13a and second end portion 13b abut against the first opposing slope 141a and second opposing slope 142a, thereby obtaining a structure capable of supporting the weight 14. In other words, a suitable structure is obtained throughout the entire operation of the rotating electric machine 1.

In this embodiment, the weight 14 is made of a non-magnetic material. With this configuration, even if the weight 14 is placed on the rotor 2, it is possible to avoid the weight 14 being affected by magnetic flux such as the magnetic flux of the second permanent magnet 12 placed on the rotor 2.

In this embodiment, the rotor 2 has multiple first permanent magnets 3 per magnetic pole. The second permanent magnet 12 is arranged on the q-axis located at the boundary between adjacent magnetic poles in the circumferential direction formed on the rotor 2 by the multiple first permanent magnets 3, and moves along the radial direction. With this configuration, the moving second permanent magnet 12 can be appropriately positioned on the rotor 2 while the multiple first permanent magnets 3 form magnetic poles on the rotor 2.

In this embodiment, the movable mechanism 10 further includes a magnet spring 16 disposed radially outside the second permanent magnet 12 and attached to the second permanent magnet 12, and the mechanism is such that the magnet spring 16 contracts due to the spring force of the magnet spring 16 when the second permanent magnet 12 returns to its original position. With this configuration, the second permanent magnet 12 can be returned to its retracted position using the spring force of the magnet spring 16 when transitioning from high rotation to low rotation. In addition, the weight 14 can be supported by the support member 13 using the spring force of the magnet spring 16 when transitioning from high rotation to low rotation or at low rotation.

Although the embodiments of the present invention have been described above, the above embodiments merely show some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

For example, the movable mechanism 10 may not have a housing frame 11, and the outer flux barrier B1 may be formed by a hole provided in the rotor 2. The rotating electric machine 1 may also be an outer rotor structure rotating electric machine. In this case, the movable mechanism 10 may be, for example, a mechanism in which the second permanent magnet 12 arranged on the outer rotor moves radially outward, that is, away from the stator, by centrifugal force, thereby reducing the magnetic flux to the stator housed in the outer rotor. In this case, the second permanent magnet 12 may be fitted with a return spring that returns the second permanent magnet 12 to its original position radially inward when transitioning from high rotation to low rotation.

REFERENCE SIGNS LIST 1 rotating electric machine 2 rotor 3 first permanent magnet 10 movable mechanism 11 housing frame 111 guide slope 12 second permanent magnet (magnet)
13 Support member 13a First tip portion 13b Second tip portion 13c First opposing surface 13d Second opposing surface 14 Weight 141a First opposing inclined surface 142a Second opposing inclined surface 15 Weight spring 16 Magnet spring B1 Outer flux barrier (flux barrier)

Claims (9)

A rotating electric machine having a rotor and a stator, and a magnet disposed on the rotor,
a movable mechanism that changes a magnetic flux of the magnet to the stator by moving the magnet in accordance with a rotation speed of the rotor,
the movable mechanism is a mechanism for reducing a magnetic flux to the stator by moving the magnet in a direction away from the stator, and includes a weight that moves the magnet by centrifugal force, and a housing frame that is assembled to the rotor by being pushed into an insertion hole provided in the rotor,
The weights are weights provided on both sides of the magnet in the circumferential direction, and each weight has an opposed inclined surface that extends obliquely radially outward in a direction from both sides of the magnet in the circumferential direction toward the center when viewed along the axial direction,
The movable mechanism further includes a support member connected to the magnet and abutting each of the opposing slopes when the magnet is in its original position.
A rotating electric machine characterized by: A rotating electric machine having a rotor and a stator, and a magnet disposed on the rotor,
a movable mechanism that changes a magnetic flux of the magnet to the stator by moving the magnet in accordance with a rotation speed of the rotor ,
the movable mechanism is a mechanism for reducing a magnetic flux to the stator by moving the magnet in a direction away from the stator, and includes a weight that moves the magnet by centrifugal force;
The rotor has a plurality of magnets per magnetic pole,
the magnet is disposed on a q-axis located at a boundary between magnetic poles adjacent to each other in a circumferential direction formed on the rotor by the plurality of magnets, and moves along a radial direction;
A rotating electric machine characterized by: 3. A rotating electric machine according to claim 1,
the movable mechanism has a flux barrier between the magnet and the stator,
The flux barrier has a length extending in a direction connecting the magnet and the stator as the magnet moves in a direction away from the stator.
A rotating electric machine characterized by: A rotating electric machine according to any one of claims 1 to 3 .
The movable mechanism further includes a weight spring attached to the weight, and the weight spring is compressed by the spring force of the weight spring when the magnet returns to its original position.
A rotating electric machine characterized by: 3. The rotating electric machine according to claim 2 ,
The movable mechanism further includes a housing frame that is assembled to the rotor by being pushed into an insertion hole provided in the rotor.
A rotating electric machine characterized by: 6. A rotating electric machine according to claim 5 ,
The weights are weights provided on both sides of the magnet in the circumferential direction, and each weight has an opposed inclined surface that extends obliquely radially outward in a direction from both sides of the magnet in the circumferential direction toward the center when viewed along the axial direction,
The movable mechanism further includes a support member connected to the magnet and abutting each of the opposing slopes when the magnet is in its original position.
A rotating electric machine characterized by: 7. A rotating electric machine according to claim 1 ,
the housing frame extends obliquely radially outward from both sides of the magnet in the circumferential direction toward the center when viewed along the axial direction, and has guide slopes that guide the weights,
When viewed along the axial direction, the support member branches and extends along the extension direction of each of the guide slopes and the radial direction, and is connected to the magnet at the portion branched and extended along the radial direction, and when the magnet is in its original position, each tip of the portion branched and extended along the extension direction of each of the guide slopes abuts against each of the opposing slopes,
the weight moves radially outward along the corresponding one of the guide slopes by centrifugal force, thereby moving the support member radially inward, thereby moving the magnet radially inward.
A rotating electric machine characterized by: A rotating electric machine according to any one of claims 1 to 7 ,
The weight is a non-magnetic material.
A rotating electric machine characterized by: A rotating electric machine according to any one of claims 1 to 8 ,
The movable mechanism further includes a magnet spring disposed radially outside the magnet and attached to the magnet, and the magnet spring is compressed by the spring force of the magnet spring when the magnet returns to its original position.
A rotating electric machine characterized by:

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