Motor rotor, and motor

Abstract

To provide a motor rotor which can be operated more stably, and a motor.SOLUTION: A rotor core of a motor rotor comprises: a pair of nonmagnetic parts which are provided between a pair of insertion holes; and a reinforcement member which is provided between the pair of nonmagnetic parts and extends in a radial direction. The insertion hole is formed in a rectangular shape defining a direction orthogonal to the radial direction as a length direction, the nonmagnetic part is spread while defining a circumferential direction crossing the length direction of the insertion hole as a length direction, and a dimension of the reinforcement member in the circumferential direction is reduced gradually from the inside to the outside in the radial direction. When an angle range formed by a pair of straight lines from an axis to both ends of the insertion hole in the circumferential direction is defined as θ1, an angle formed by a pair of straight lines from the axis to both ends of the nonmagnetic part in the circumferential direction is defined as θ2 and an angle formed by a pair of straight lines from the axis to both ends of an outer peripheral side edge of the reinforcement member in the circumferential direction is defined as θ3, θ1>θ2>θ3 is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an electric motor rotor and an electric motor. [Background technology]

[0002] The electric motor includes a rotor having a magnet and a rotor core, and a stator covering the rotor from the outer periphery and having a coil. The rotor core is formed with a plurality of insertion holes spaced apart in the circumferential direction. Magnets are inserted and held in each of the insertion holes (for example, see Patent Document 1 below). The insertion holes are generally formed slightly larger than the longitudinal dimension of the magnet.

[0003] When a current is passed through the stator coil, the electromagnetic force generated between the coil and the magnets applies a rotational force to the rotor. When the rotor rotates, centrifugal force is generated in the magnets. The portions between the insertion holes function as reinforcing members to resist this centrifugal force. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6992368 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the insertion holes are merely formed slightly larger than the magnets as described above, the stress caused by the centrifugal force acting on the magnets will be concentrated at both circumferential ends of the reinforcing member, which may result in deformation or damage to the rotor.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an electric motor rotor and an electric motor that are capable of operating more stably. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, an electric motor rotor according to the present disclosure is an electric motor rotor including a rotor core rotatable about an axis, and magnets inserted into a plurality of insertion holes arranged in the rotor core at intervals in the circumferential direction, the rotor core having a pair of non-magnetic portions provided between a pair of the insertion holes adjacent to each other in the circumferential direction, and a reinforcing member provided between the pair of non-magnetic portions and extending in the radial direction, the insertion hole has a rectangular shape with a longitudinal direction perpendicular to the radial direction as viewed from the axial direction, and the non-magnetic portions extends with its longitudinal direction being a circumferential direction that intersects with the longitudinal direction of the insertion hole, and the reinforcing member is configured such that its circumferential dimension gradually decreases from the radially inner side to the radially outer side, and when the angular range formed by a pair of straight lines from the axis to both circumferential ends of the insertion hole is θ1, the angle formed by a pair of straight lines from the axis to both circumferential ends of the non-magnetic portion is θ2, and the angle formed by a pair of straight lines from the axis to both circumferential ends of the outer peripheral edge of the reinforcing member is θ3, the relationship θ1>θ2>θ3 is satisfied.

[0008] An electric motor according to the present disclosure includes the above-mentioned electric motor rotor and a stator that covers the electric motor rotor from the outer periphery side. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide an electric motor rotor and an electric motor capable of operating more stably. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a configuration of an electric motor according to an embodiment of the present disclosure, viewed from an axial direction. [Diagram 2] 1 is an enlarged cross-sectional view of a main portion of an electric motor rotor according to an embodiment of the present disclosure, viewed from the axial direction; [Diagram 3] 1 is a table showing the relationship between the ratio of the angle range of the magnet / angle range of the non-magnetic portion and centrifugal stress in examples and comparative examples of the present disclosure. [Figure 4]1 is a graph showing the relationship between the ratio of the angle range of the magnet / the angle range of the non-magnetic portion and centrifugal stress in examples and comparative examples of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (Motor configuration) Hereinafter, an electric motor 1 and an electric motor rotor (rotor 10) according to an embodiment of the present disclosure will be described with reference to Fig. 1 and Fig. 2. This electric motor 1 can be mounted as a compressor driving source for an air conditioner, a driving source for various industrial machines and transport machines, etc.

[0012] As shown in Fig. 1, the electric motor 1 includes a rotor 10 and a stator 20. The rotor 10 is rotatable around an axis O. The rotor 10 includes a rotor core 11 and magnets 12. The rotor core 11 has a circular cross-sectional shape centered on the axis O. Although not shown in detail, the rotor core 11 is integrally formed by stacking a plurality of magnetic steel plates punched into the same shape in the direction of the axis O.

[0013] Insertion holes 13 into which magnets 12 are inserted are formed at positions slightly inward from the outer circumferential surface of rotor core 11. A plurality of insertion holes 13 are formed at equal intervals in the circumferential direction of axis O. In the example of Fig. 1, one magnet 12 is inserted into each of the six insertion holes 13. In other words, this electric motor 1 is a six-pole motor.

[0014] As shown in FIG. 2, the insertion hole 13 has a rectangular cross-sectional shape with the longitudinal direction perpendicular to the radial direction of the axis O. Therefore, the magnet 12 inserted into this insertion hole 13 also has a rectangular cross-sectional shape. Between a pair of insertion holes 13 adjacent to each other in the circumferential direction, a gap is formed as a pair of nonmagnetic portions 14. The nonmagnetic portions 14 extend in the circumferential direction intersecting with the longitudinal direction of the magnet 12. The nonmagnetic portions 14 and the insertion hole 13 extend in different directions, but are located at the same position in the radial direction. That is, the inner peripheral surface of the nonmagnetic portion 14 and the inner peripheral surface of the insertion hole 13 intersect with each other. Also, the outer peripheral surface of the nonmagnetic portion 14 and the outer peripheral surface of the insertion hole 13 intersect with each other.

[0015] The nonmagnetic portion 14 has a trapezoidal cross-sectional shape when viewed from the direction of the axis O. An outer peripheral edge 15 of the nonmagnetic portion 14 is longer than an inner peripheral edge 16. These edges are parallel to each other. Note that "parallel" here refers to being substantially parallel, and slight manufacturing errors are allowed. A protrusion 17 protruding toward the outer peripheral side is provided on the inner peripheral edge 16 of the nonmagnetic portion 14 at a portion facing the magnet 12. The protrusion 17 is provided to restrain the magnet 12 from both circumferential sides.

[0016] A reinforcing member 30 is formed between the pair of non-magnetic portions 14. The reinforcing member 30 is provided to resist the centrifugal force generated in the magnets 12 when the rotor 10 rotates. The reinforcing member 30 is configured so that the circumferential dimension gradually decreases from the radially inner side to the radially outer side. Therefore, the reinforcing member 30 has a triangular shape that is convex toward the radially outer side. In addition, a corner 19 formed by a circumferential edge 18 of the reinforcing member 30 and an outer peripheral edge 15 of the non-magnetic portion 14 has an arc shape when viewed from the axis O direction. In other words, these edges do not intersect at an acute angle.

[0017] Here, the angle formed by a pair of straight lines extending from the position of the axis O to the ends of the magnet 12 on both sides in the circumferential direction (the circumferential ends 12a of the outer peripheral edge) is θ1 (note that in FIG. 2, one of the straight lines is omitted for the sake of simplicity). The angle formed by a pair of straight lines extending from the position of the axis O to the ends of the nonmagnetic part 14 on both sides in the circumferential direction (the ends on the outer peripheral side) is θ2. Furthermore, the angle formed by a pair of straight lines extending from the position of the axis O to both ends at the end on the outer peripheral side of the reinforcing member 30 is θ3. At this time, the dimensions of each part are set so that the relationship θ1>θ2>θ3 is established. In addition, the ratio of θ1 to θ2 (i.e., the value of θ1 / θ2) is preferably 1.5 or more and 7.0 or less. More preferably, the value of θ1 / θ2 is 2.0 or more and 6.0 or less. Most preferably, the value of θ1 / θ2 is 2.5 or more and 5.0 or less.

[0018] The stator 20 covers the rotor 10 from the outer periphery side, and is formed into a cylindrical shape centered on the axis O. Although not shown, the stator 20 has a stator 20 core and a coil. The coil is formed by winding a copper wire multiple times around the teeth of the stator 20 core.

[0019] When a current is supplied to the stator 20, an electromagnetic force is generated between the coil of the stator 20 and the magnet 12 of the rotor 10. This electromagnetic force provides rotational energy about the axis O to the rotor 10, thereby driving the rotor 10 to rotate. Alternatively, when a rotational force is applied to the rotor 10, an induced electromotive force is generated between the magnet 12 of the rotor 10 and the coil of the stator 20, causing the rotor 10 to function as a generator.

[0020] (Action and effect) When the rotor 10 rotates, a centrifugal force toward the outer periphery is generated in the magnets 12. Between the insertion holes 13, reinforcing members 30 are provided to resist this centrifugal force.

[0021] However, if the longitudinal dimension of the nonmagnetic portion 14 (i.e., the dimension proportional to the above-mentioned θ2) is smaller than the longitudinal dimension of the magnet 12 (i.e., the dimension proportional to the above-mentioned θ1), the stress caused by the centrifugal force generated in the magnet 12 will concentrate on both circumferential ends of the reinforcing member 30. Specifically, the centrifugal force acting on the magnet 12 acts directly on the outer peripheral end of the reinforcing member 30, which is the circumferential end of the nonmagnetic portion 14, causing bending deformation starting from the outer peripheral end. This bending deformation causes stress concentration in the reinforcing member 30, which may result in deformation or damage to the rotor 10. Therefore, in order to solve this problem, the above-mentioned configurations are adopted in this embodiment.

[0022] According to the above configuration, the angles θ1, θ2, and θ3 formed by the straight lines extending from the axis O position to the magnet 12, the nonmagnetic portion 14, and the reinforcing member 30 satisfy the relationship θ1>θ2>θ3. As a result, it is possible to ensure a relatively large circumferential angle range of the nonmagnetic portion 14 based on the circumferential angle range of the magnet 12 (i.e., the longitudinal dimension). Therefore, a large distance is ensured from the circumferential end 12a on the outer circumferential side of the magnet 12 to the circumferential end (corner 19) of the reinforcing member 30. Therefore, bending deformation caused by the centrifugal force acting on the magnet 12 with the rotation of the rotor 10 is unlikely to occur in the rotor core 11. An example of the shape of the rotor core 11 when this bending deformation occurs is shown by the two-dot chain lines in FIG. 1 and FIG. 2. As a result of suppressing such bending deformation, it is possible to prevent stress from concentrating on the circumferential end of the reinforcing member 30. 2, the starting point of bending deformation is far away from the edge (i.e., corner 19) on the outer circumferential side of reinforcing member 30, and therefore it is possible to effectively avoid stress concentration at corner 19. This reduces the possibility of deformation or damage to rotor 10 due to the above-mentioned stress concentration, and allows electric motor 1 to operate more stably.

[0023] In addition, the reinforcing member 30 is formed so that the circumferential dimension decreases from the radially inner side to the radially outer side. This makes it possible to ensure a larger separation distance between the outer peripheral edge 15 of the nonmagnetic portion 14 and the magnet 12. This makes it difficult for the bending deformation described above to occur, and as a result, it becomes possible to further reduce the stress concentration on the reinforcing member 30.

[0024] With the above configuration, the non-magnetic portion 14 is an air gap, which reduces the possibility of a magnetic path being formed around the magnet 12. This reduces eddy current loss in the motor rotor, allowing the motor 1 to operate more stably and efficiently.

[0025] According to the above configuration, corners 19 on both circumferential sides of nonmagnetic portion 14 are arc-shaped, which makes it possible to more effectively reduce the above-mentioned stress concentration caused by the centrifugal force of magnet 12. This further reduces the possibility of deformation or damage to the motor rotor, making it possible to operate motor 1 more stably.

[0026] According to the above configuration, the ratio of θ1 to θ2 is 1.5 or more and 7.0 or less, so a relatively large distance is ensured from the circumferential end of magnet 12 to the circumferential end of reinforcing member 30. This makes it possible to prevent stress caused by centrifugal force acting on magnet 12 as rotor 10 rotates from concentrating on the circumferential end of reinforcing member 30. As a result, the possibility of deformation or damage to rotor 10 due to the above-mentioned stress concentration is reduced, and it becomes possible to operate electric motor 1 more stably. EXAMPLES

[0027] Next, an embodiment and a comparative example of the above-mentioned electric motor 1 and electric motor rotor will be described with reference to FIG. 3 and FIG. 4. As shown in the table of FIG. 3, in the embodiment, the value of θ1 is 38.54°, the value of θ2 is 10.15°, and the value of θ3 is 1.2°. In Comparative Example 1, the value of θ1 is 48.23°, the value of θ2 is 4.96°, and the value of θ3 is 1.84°. In Comparative Example 2, the value of θ1 is 30.63°, the value of θ2 is 1.85°, and the value of θ3 is 1.73°. In this case, the value of θ2 / θ1 is 0.26 in the embodiment, 0.1 in Comparative Example 1, and 0.06 in Comparative Example 2.

[0028] For each of the above examples, the centrifugal stress generated at the outer peripheral end of the reinforcing member 30 was calculated by numerical analysis. As a result, when Comparative Example 1 was set as the standard (1.0), the Examples showed a significant reduction in stress of 0.39. In addition, the Comparative Example 2 showed a value of 1.14. A graph showing these relationships is shown in FIG. 4. Thus, it was confirmed that the Examples had the effect of significantly reducing the centrifugal stress generated in the reinforcing member 30 compared to the conventional configuration.

[0029] (Other embodiments) The above describes in detail the embodiments and examples of the present disclosure with reference to the drawings. However, the specific configurations are not limited to these embodiments, and design changes and the like that do not deviate from the gist of the present disclosure are also included.

[0030] For example, the number of magnets 12 (number of poles) of the motor rotor described above is an example, and the number of poles can be changed as appropriate according to the design and specifications. Even in this case, by maintaining the angle ranges of θ1, θ2, and θ3 described above, it is possible to obtain the same effects as those described above.

[0031] In the above embodiment, the insertion hole 13 and the non-magnetic portion 14 are described as extending in a direction perpendicular to the radial direction. However, these aspects are not limited to the above embodiment, and the insertion hole 13 may intersect with the radial direction at an angle of 90° or less. In this case, the pair of magnets 12 are arranged in a V-shape. The extension direction of the non-magnetic portion 14 may also form an angle of 90° or less with the radial direction. Even with this configuration, the same effects as those described above can be obtained by maintaining the angle ranges of θ1, θ2, and θ3.

[0032] <Additional Notes> The electric motor rotor and the electric motor 1 described in each embodiment can be understood, for example, as follows.

[0033] (1) An electric motor rotor according to a first aspect is an electric motor rotor including a rotor core 11 rotatable around an axis O and magnets 12 inserted into a plurality of insertion holes 13 arranged in the rotor core 11 at intervals in the circumferential direction, the rotor core 11 having a pair of non-magnetic portions 14 provided between a pair of the insertion holes 13 adjacent to each other in the circumferential direction and a reinforcing member 30 provided between the pair of non-magnetic portions 14 and extending in the radial direction, the insertion hole 13 has a rectangular shape with a longitudinal direction perpendicular to the radial direction as viewed from the direction of the axis O, and the non-magnetic portions 14 extends with its longitudinal direction being the circumferential direction that intersects the longitudinal direction of the insertion hole 13, and the reinforcing member 30 is configured so that its circumferential dimension gradually decreases from the radially inner side to the outer side, and when the angular range formed by a pair of straight lines from the axis O to both circumferential ends of the insertion hole 13 is θ1, the angle formed by a pair of straight lines from the axis O to both circumferential ends of the non-magnetic portion 14 is θ2, and the angle formed by a pair of straight lines from the axis O to both circumferential ends at the outer peripheral edge of the reinforcing member 30 is θ3, the relationship θ1>θ2>θ3 is satisfied.

[0034] According to the above configuration, the angles θ1, θ2, and θ3 formed by the straight lines extending from the axis O position with respect to the magnet 12, the nonmagnetic portion 14, and the reinforcing member 30 satisfy the relationship θ1>θ2>θ3. This makes it possible to ensure a relatively large circumferential angle range of the nonmagnetic portion 14 based on the circumferential angle range of the magnet 12 (i.e., the longitudinal dimension). This makes it possible to prevent stress from concentrating on the circumferential end portion of the reinforcing member 30. As a result, the possibility of deformation or damage of the rotor 10 due to stress concentration is reduced, and the electric motor 1 can be operated more stably.

[0035] (2) The electric motor rotor according to a second aspect is the electric motor rotor of (1), in which the non-magnetic portion 14 is an air gap.

[0036] With the above configuration, the non-magnetic portion 14 is an air gap, which reduces the possibility of a magnetic path being formed around the magnet 12. This reduces eddy current loss in the motor rotor, allowing the motor 1 to operate more stably and efficiently.

[0037] (3) The electric motor rotor according to a third aspect is the electric motor rotor of (1) or (2), wherein the corners 19 on both circumferential sides on the outer periphery of the non-magnetic portion 14 are arc-shaped when viewed from the axis O direction.

[0038] According to the above configuration, corners 19 on both circumferential sides of nonmagnetic portion 14 are arc-shaped, which makes it possible to more effectively reduce the above-mentioned stress concentration caused by the centrifugal force of magnet 12. This further reduces the possibility of deformation or damage to the motor rotor, making it possible to operate motor 1 more stably.

[0039] (4) An electric motor rotor according to a fourth aspect is the electric motor rotor according to any one of (1) to (3), wherein the ratio of θ1 to θ2 is equal to or greater than 1.5 and equal to or less than 7.0.

[0040] According to the above configuration, a large distance is ensured between the circumferential ends of the magnets 12 and the circumferential ends of the reinforcing members 30. This makes it possible to prevent stress caused by centrifugal force acting on the magnets 12 as the rotor 10 rotates from concentrating on the circumferential ends of the reinforcing members 30. As a result, the possibility of deformation or damage to the rotor 10 due to the above-mentioned stress concentration is reduced, and the electric motor 1 can be operated more stably.

[0041] (5) The electric motor 1 according to a fifth aspect includes the electric motor rotor according to any one of (1) to (4) and a stator 20 that covers the electric motor rotor from the outer periphery side.

[0042] According to the above configuration, it is possible to provide an electric motor 1 capable of operating more stably. [Explanation of symbols]

[0043] REFERENCE SIGNS LIST 1...electric motor 10...rotor 11...rotor core 12...magnet 13...insertion hole 14...non-magnetic portion 15...outer peripheral edge 16...inner peripheral edge 17...rib 18...circumferential edge 19...corner 20...stator 30...reinforcing member O...axis

Claims

1. A rotor core rotatable about an axis; magnets are inserted into a plurality of insertion holes arranged at intervals in the circumferential direction within the rotor core; An electric motor rotor comprising: The rotor core is a pair of nonmagnetic portions provided between a pair of the insertion holes adjacent to each other in the circumferential direction; a reinforcing member provided between the pair of nonmagnetic portions and extending in a radial direction; having the insertion hole has a rectangular shape with a longitudinal direction perpendicular to the radial direction when viewed from the axial direction, the nonmagnetic portion extends with a longitudinal direction being a circumferential direction intersecting the longitudinal direction of the insertion hole, and the reinforcing member is configured such that a circumferential dimension gradually decreases from the radial inner side toward the radial outer side, An electric motor rotor in which the relationship θ1 > θ2 > θ3 is satisfied, where θ1 is the angular range formed by a pair of straight lines from the axis to both circumferential ends of the insertion hole, θ2 is the angle formed by a pair of straight lines from the axis to both circumferential ends of the non-magnetic portion, and θ3 is the angle formed by a pair of straight lines from the axis to both circumferential ends of the outer peripheral edge of the reinforcing member.

2. 2. The electric motor rotor according to claim 1, wherein the non-magnetic portion is an air gap.

3. 3. The electric motor rotor according to claim 1, wherein corners on both sides in the circumferential direction on the outer periphery side of the nonmagnetic portion are arc-shaped when viewed from the axial direction.

4. 3. The electric motor rotor according to claim 1, wherein a ratio of said θ1 to said θ2 is equal to or greater than 1.5 and equal to or less than 7.

0.

5. An electric motor rotor according to claim 1 or 2; a stator that covers the electric motor rotor from an outer periphery side; An electric motor comprising:

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