Rotor and motor

Abstract

The rotor (2) comprises a rotor core (4) fixed to a shaft (3) which serves as a rotating shaft, and an end ring (5) provided at least on one of both ends of the rotor core (4) in the direction of the rotation axis of the shaft (3). The end ring (5) provided at least on one of both ends of the rotor core (4) has a plurality of protrusions (50) protruding in the direction of the rotation axis of the shaft (3). Each protrusion (50) is removable in order to adjust the rotation balance, and is configured so that a balance weight (6) can be attached to increase the weight of the end ring (5) in order to adjust the rotation balance.

Description

[Technical field]

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

[0002] Conventionally, rotors constituting electric motors are known. The rotational balance of the rotor is adjusted to obtain stable rotation and torque. For example, the rotor disclosed in Patent Document 1 includes a rotor core and a balancer provided axially away from at least one of both axial end faces of the rotor core. The balancer has a balancer body formed in an annular shape and a plurality of protrusions formed integrally with the balancer body. The rotational balance of the rotor is adjusted by removing some or all of the plurality of protrusions to reduce the weight of the balancer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-90242 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology disclosed in Patent Document 1, the only way to adjust the rotational balance of the rotor is to remove some or all of the protrusions and reduce the weight of the balancer. Therefore, if the amount of imbalance in the rotor rotational balance is large, it may not be possible to accurately adjust the rotational balance by simply reducing the weight of the balancer.

[0005] The present disclosure has been made in consideration of the above, and has an object to provide a rotor whose rotational balance can be adjusted with high precision even if the amount of unbalance of the rotor is large. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the rotor according to the present disclosure includes a rotor core fixed to a shaft serving as a rotating shaft, and an end ring provided on at least one of both ends of the rotor core in the axial direction of the shaft. The end ring provided on at least one of both ends of the rotor core has a plurality of protrusions protruding in the axial direction of the shaft. At least two protrusions are provided radially from the center of rotation of the shaft, and at least two protrusions are provided circumferentially of a concentric circle centered on the center of rotation. The multiple protrusions provided radially from the center of rotation of the shaft are provided such that the product of the distance from the center of rotation to the axial center of each protrusion and its weight is equal to each other. Each protrusion is removable to adjust the rotational balance, and is configured to allow attachment of a balance weight that increases the weight of the end ring to adjust the rotational balance. Effect of the Invention

[0007] According to the rotor according to the present disclosure, it is possible to achieve the effect that the rotational balance can be adjusted with high precision even if the amount of unbalance of the rotor is large. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a front view showing an electric motor according to a first embodiment; [Diagram 2] FIG. 2 is a side view of the electric motor according to the first embodiment, as viewed from the direction of the arrow II in FIG. [Diagram 3] Cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 1 is a plan view showing a balance weight of a rotor according to a first embodiment; [Diagram 5] Cross-sectional view taken along the arrows VV in Figure 4 [Figure 6] FIG. 1 is an explanatory diagram showing a rotor according to a first embodiment, in which a balance weight is attached to a protrusion; [Figure 7] FIG. 11 is an explanatory diagram showing a rotor according to a second embodiment. [Figure 8] Cross-sectional view taken along the line VIII-VIII in FIG. 7. [Figure 9] FIG. 11 is a cross-sectional view showing a modified example of the rotor according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a rotor and an electric motor according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] Embodiment 1 Fig. 1 is a front view showing an electric motor according to a first embodiment. Fig. 2 is a side view of the electric motor according to the first embodiment, seen from the direction of arrow II shown in Fig. 1. As shown in Figs. 1 and 2, an electric motor 100 according to the first embodiment includes a cylindrical stator 1, a rotor 2 that is surrounded by the stator 1 and drives to rotate, and a shaft 3 that rotatably supports the rotor 2. The shaft 3 is disposed so as to penetrate the rotor 2. Hereinafter, the direction in which the shaft 3 extends is referred to as a rotation axis direction X.

[0011] The stator 1 includes, for example, a stator core (not shown), an insulator, and a winding. The stator core is formed into a cylindrical shape extending in the direction of the rotation axis X by stacking, for example, a plurality of electromagnetic steel sheets, which are a magnetic material, in the direction of the rotation axis X. The insulators are attached to both ends of the stator core in the axial direction, and insulate the stator core from the winding. The winding is wound around the stator core via the insulators.

[0012] As shown in Fig. 1 and Fig. 2, the rotor 2 includes a rotor core 4 and a pair of end rings 5. The rotor core 4 is formed in a generally cylindrical shape extending in the rotation axis direction X by, for example, stacking a plurality of electromagnetic steel sheets, which are a magnetic material, in the rotation axis direction X. The rotor core 4 is formed with a through hole (not shown). The through hole is provided in the center of the rotor core 4 and passes through in the rotation axis direction X. The shaft 3 is inserted into the through hole. Note that the rotor core 4 may be configured such that, for example, a plurality of magnet insertion holes are formed penetrating the rotor core 4 in the axial direction, and a permanent magnet is inserted into each magnet insertion hole.

[0013] 1 and 2, the end rings 5 ​​are fixed to both ends of the rotor core 4 in the rotational axis direction X, i.e., to the load side and anti-load side of the rotor core 4. The end rings 5 ​​are made of non-magnetic plate-shaped members. An axial hole into which the shaft 3 is inserted is provided in the center of the end ring 5. Note that the end rings 5 ​​do not necessarily need to be provided at both ends of the rotor core 4 in the rotational axis direction X, and may be provided at least at one end of the rotor core 4.

[0014] The rotational balance of the rotor 2 is adjusted to obtain stable rotation and torque. In conventional rotors, the rotational balance is adjusted, for example, by reducing the weight of the end rings 5 ​​or by increasing the weight of the end rings 5 ​​by providing balance weights to the end rings 5. However, if the amount of imbalance in the rotational balance of the rotor is large, the amount by which the end rings 5 ​​are reduced or increased becomes large, and a configuration that only reduces or increases the weight of the end rings 5 ​​may not be able to accurately adjust the rotational balance.

[0015] Therefore, in the rotor 2 in the first embodiment, the end ring 5 has a plurality of protrusions 50 protruding toward the rotation axis direction X. Each protrusion 50 is removable to adjust the rotation balance of the rotor 2, and is configured to allow a balance weight 6 to be attached to increase the weight of the end ring 5 in order to adjust the rotation balance of the rotor 2. As shown in Figs. 1 and 2, the protrusions 50 are regularly arranged along the circumferential direction of a concentric circle centered on the rotation center C of the shaft 3. As an example, twelve protrusions 50 are provided as shown in Figs. 1 and 2. The plurality of protrusions 50 are formed to have the same shape, size, and weight. The number of protrusions 50 is not limited to the twelve shown in the figure, and may be two or more. Moreover, the protrusions 50 do not necessarily have to be configured to have the same shape, size, and weight, and may be configured to have different shapes, sizes, and weights. Moreover, the protrusions 50 do not necessarily have to be provided on both of the pair of end rings 5, and may be configured to be provided on at least one of the end rings 5.

[0016] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. As shown in FIG. 3, each protrusion 50 is formed of a plurality of protrusions 50a, 50b, 50c having different outer shapes so that the outer shape gradually decreases along the rotation axis direction X. The protrusion 50 shown in FIG. 3 has, as an example, a protrusion 50a having the largest outer shape, a protrusion 50b having an outer shape smaller than the protrusion 50a, and a protrusion 50c having an outer shape smaller than the protrusion 50b. That is, the protrusion 50 is formed so that the outer shape decreases in three stages toward the rotation axis direction X. All of the protrusions 50a, 50b, 50c, or some of the protrusions 50b, 50c of each protrusion 50 can be removed. When some of the protrusions 50b, 50c are removed, for example, the protrusions 50b and 50c, or only the protrusion 50c can be removed. The protrusions 50 have the protrusions 50a, 50b, 50c removed, which are necessary to adjust the rotation balance of the rotor 2. In this manner, in the rotor 2 in the first embodiment, the protrusions 50 have the protrusions 50a, 50b, 50c, so that the locations at which the end rings 5 ​​are reduced in weight can be set in detail, and the rotation balance can be adjusted with high precision. Note that the protrusions 50 are not limited to the configuration having the three protrusions 50a, 50b, 50c shown in the figure, and may have two protrusions or four or more protrusions. Also, the protrusions 50 may be configured with a single protrusion.

[0017] FIG. 4 is a plan view showing the balance weight of the rotor according to the first embodiment. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4. The balance weight 6 shown in FIGS. 4 and 5 is provided to increase the weight of the end ring 5 and adjust the rotation balance of the rotor 2. The balance weight 6 has a cylindrical body portion 60 that fits into the protrusion 50, and a holding portion 61 that holds the cylindrical body portion 60 in a state where it is fitted into the protrusion 50. The cylindrical interior of the cylindrical body portion 60 has an inner shape that fits into each of the protrusions 50a, 50b, and 50c of the protrusion 50, and is fitted into one of the three protrusions 50a, 50b, and 50c. The holding portion 61 is provided to hold the cylindrical body portion 60 in a state where it is fitted into the protrusion 50 so that the balance weight 6 does not come off the protrusion 50. The holding portion 61 is formed as a pair of protrusions that protrude from the opposing inner wall surfaces of the cylindrical portion 60 toward the protruding portions 50a, 50b, and 50c and pinch the side surfaces of the protruding portions 50a, 50b, and 50c. When the balance weight 6 is fitted into the protruding portions 50a, 50b, and 50c, the holding portion 61 is pushed in while elastically deforming and opening. At the tip of the holding portion 61, a barb that bites into the side surfaces of the protruding portions 50a, 50b, and 50c is formed. When the balance weight 6 is attached to the protruding portions 50a, 50b, and 50c, it is only necessary to fit the cylindrical portion 60 into the protruding portions 50a, 50b, and 50c, and there is no need to drive it in strongly. Therefore, for example, there is no risk of the rotor 2 being damaged by the impact of driving in when attaching the balance weight 6. In addition, the burden on the worker due to the driving in operation can be reduced. In addition, the retaining portion 61 is not limited to the pair of protrusions shown in the figure, and may be in other forms as long as it can maintain the state in which the tubular portion 60 is fitted into the protrusion portion 50 so that the balance weight 6 does not slip out of the protrusion portion 50.

[0018] FIG. 6 is an explanatory diagram showing a rotor according to the first embodiment, in which balance weights are attached to the protrusions. As shown in FIG. 6, the balance weights 6 are attached to the protrusions 50 that need to adjust the rotation balance of the rotor 2 among the multiple protrusions 50. The balance weights 6 are attached to all or some of the protrusions 50a, 50b, 50c among the protrusions 50a, 50b, 50c of each protrusion 50. FIG. 6 shows, as an example, a state in which three balance weights 6 of different sizes are attached to the corresponding protrusions 50a, 50b, 50c. The balance weights 6 are held in a state in which the cylindrical portion 60 is fitted to the protrusions 50a, 50b, 50c by clamping the sides of the protrusions 50a, 50b, 50c with the tip of the holding portion 61.

[0019] The balance weight 6 may be provided, for example, only on the protruding portion 50a, which has the largest outer shape, among the three protruding portions 50a, 50b, and 50c, or may be provided on the protruding portion 50a, which has the largest outer shape, and the protruding portion 50c, which has the smallest outer shape. The protruding portions 50a, 50b, and 50c on which the balance weight 6 is provided are appropriately determined in accordance with the adjustment of the rotational balance of the rotor 2. In this way, in the rotor 2 in the first embodiment, the locations where the balance weight 6 is provided to increase the weight of the end rings 5 ​​can be precisely set, so that the rotational balance can be adjusted with high precision.

[0020] Furthermore, the shape and size of the balance weight 6 are not limited to the configuration shown in the figure. Furthermore, the balance weight 6 is not limited to a configuration in which it is attached to each of the protrusions 50a, 50b, and 50c, and may be configured as one unit so that it can be attached to the three protrusions 50a, 50b, and 50c together, for example. Furthermore, the holding portion 61 is not limited to the configuration shown in the figure, and may have other configurations. In short, the balance weight 6 may have other forms as long as it can be attached to the protrusion 50.

[0021] As described above, the rotor 2 according to the first embodiment includes the rotor core 4 fixed to the shaft 3 serving as a rotating shaft, and the end ring 5 provided on at least one of the two ends of the rotor core 4 in the direction of the rotation axis X of the shaft 3. The end ring 5 provided on at least one of the two ends of the rotor core 4 has a plurality of protrusions 50 protruding toward the direction of the rotation axis X of the shaft 3. Each of the protrusions 50 is removable in order to adjust the rotation balance, and is configured to allow the attachment of a balance weight 6 that increases the weight of the end ring 5 in order to adjust the rotation balance.

[0022] Therefore, in order to adjust the rotational balance of the rotor 2 according to the first embodiment, the protrusions 50 can be removed to reduce the weight of the end rings 5, and the balance weights 6 can be attached to the protrusions 50 to increase the weight of the end rings 5. This makes it possible to precisely adjust the rotational balance even if the amount of unbalance of the rotor 2 is large.

[0023] Moreover, the balance weight 6 attached to the protrusion 50 has a cylindrical portion 60 having an inner shape that fits into the protrusion 50, and a retaining portion 61 that maintains the state in which the cylindrical portion 60 is fitted into the protrusion 50. This makes it possible to maintain the state in which the balance weight 6 is attached to the protrusion 50 so that the balance weight 6 does not come off the protrusion 50 even when the rotor 2 rotates at high speed.

[0024] In addition, each protrusion 50 is formed by a plurality of protrusions 50a, 50b, 50c with different outer shapes so that the outer shape gradually becomes smaller along the rotation axis direction X of the shaft 3. This allows the end ring 5 to be reduced in weight by gradually removing the protrusions 50a, 50b, 50c of the protrusion 50 in accordance with the amount of imbalance of the rotor 2, or the end ring 5 to be increased in weight by gradually attaching the balance weights 6 to the protrusions 50a, 50b, 50c, so that the rotation balance can be adjusted with high precision. In addition, since each protrusion 50 has a plurality of protrusions 50a, 50b, 50c, it also serves as a guide for the amount of the protrusions 50a, 50b, 50c to be removed and the amount of the balance weights 6 to be attached to the protrusions 50a, 50b, 50c, so that the workability of the work of adjusting the rotation balance can be improved.

[0025] Embodiment 2 Next, a rotor according to the second embodiment will be described. Fig. 7 is an explanatory diagram showing the rotor according to the second embodiment. Fig. 8 is a cross-sectional view taken along line VIII-VIII shown in Fig. 7.

[0026] 7 and 8, each end ring 5 of the rotor 2 according to the second embodiment has three protrusions 51, 52, 53 arranged in the order of protrusions 53, 52, 51 along the radial direction from the rotation center C of the shaft 3, and eight protrusions are arranged regularly along the circumferential direction of a concentric circle centered on the rotation center C of the shaft 3. That is, each end ring 5 has a total of 24 protrusions 51, 52, 53. By providing the end ring 5 with a plurality of protrusions 51, 52, 53 in this way, it is possible to finely set the portions where the end ring 5 is reduced in weight by removing the protrusions 51, 52, 53 and the portions where the end ring 5 is increased in weight by installing the balance weight 6, thereby increasing the range of adjustment and enabling the rotation balance of the rotor 2 to be adjusted with high precision.

[0027] Moreover, the protrusion 51 is located on the outermost circumference of the end ring 5. The protrusion 53 is located on the innermost circumference of the end ring 5. The protrusion 52 is provided between the protrusions 51 and 53. The protrusions 51, 52, and 53 in the same row provided along the radial direction from the rotation center C of the shaft 3 have the same shape and weight. The protrusions 51, 52, and 53 provided along the circumferential direction of a concentric circle centered on the rotation center C of the shaft 3 have the same shape and weight. The balance amount that can be adjusted by removing the protrusions 51, 52, and 53 and the balance amount that can be adjusted by attaching balance weights 6 of the same weight to the protrusions 51, 52, and 53 are proportional to the distance from the rotation center C when the shapes and weights of the protrusions 51, 52, and 53 are the same.

[0028] Here, the distance from the rotation center C of the shaft 3 to the outer surface of the end ring 5 is r0. The position of the axial center of the protrusion 51 located at the outermost periphery is r1 away from the rotation center C of the shaft 3. The balance amount that changes when the protrusion 51 is removed is weight M×r1 / r0. The position of the axial center of the protrusion 52 located in the middle is r2 away from the rotation center C of the shaft 3. The balance amount that changes when the protrusion 52 is removed is weight M×r2 / r0. The position of the axial center of the protrusion 53 located at the innermost periphery is r3 away from the rotation center C of the shaft 3. The balance amount that changes when the protrusion 53 is removed is weight M×r3 / r0. That is, the balance amount that can be adjusted by removing the protrusions 51, 52, and 53 and the balance amount that can be adjusted by attaching balance weights 6 having the same weight to the protrusions 51, 52, and 53 are larger in the order of the protrusions 51, the protrusions 52, and the protrusions 53. Therefore, the closer the axis of the protrusion 53 is to the rotation center C, the smaller the adjustable rotation moment becomes, and the more precisely the balance amount can be adjusted.

[0029] FIG. 9 is a cross-sectional view showing a modified example of the rotor according to the second embodiment. As shown in FIG. 9, the protrusions 51, 52, and 53 in the same row provided along the radial direction from the rotation center C of the shaft 3 are provided so that the product of the distance from the rotation center C to the axial center of each of the protrusions 51, 52, and 53 and the weight is equal to each other. For example, the weight of the protrusion 51 located at the outermost periphery is M1. The weight of the protrusion 52 located in the middle is M2, which is heavier than M1. The weight of the protrusion 53 located at the innermost periphery is M3, which is heavier than M2. In this case, for example, the weight M1×r1 / r0, which is the balance amount that changes when the protrusion 51 is removed, the weight M2×r2 / r0, which is the balance amount that changes when the protrusion 52 is removed, and the weight M3×r3 / r0, which is the balance amount that changes when the protrusion 53 is removed, are provided so as to be equal to each other. As a result, the rotor 2 can be adjusted to the same balance amount even if any of the protrusions 51, 52, 53 is removed to reduce the weight. As a result, when adjusting the rotation balance during the manufacture of the rotor 2, it is necessary to check only the phases of the protrusions 51, 52, 53, which contributes to preventing adjustment errors.

[0030] In addition, the weights of the balance weights 6 attached to the protrusions 51, 52, 53 in the same row provided in the radial direction from the rotation center C of the shaft 3 are adjusted according to the outer diameters of the protrusions 51, 52, 53, so that the product of the weight and the distance from the rotation center C to the axial center of each protrusion 51, 52, 53 is equal to each other. As a result, the rotor 2 can be adjusted to the same balance amount even if the balance weights 6 are attached to any of the protrusions 51, 52, 53 to increase their weight. Even in this case, when adjusting the rotation balance during the manufacture of the rotor 2, it is necessary to check only the phases of the protrusions 51, 52, 53, which contributes to suppressing adjustment errors.

[0031] The arrangement of the protrusions 51, 52, 53 is not limited to the configuration shown in Figs. 7 to 9. For example, the protrusions may be configured to have two or more protrusions arranged in a radial direction from the rotation center C of the shaft 3. The protrusions may be configured to have two or more protrusions arranged in a circumferential direction of a concentric circle centered on the rotation center C of the shaft 3. The protrusions are not limited to the configuration having three protrusions as shown in the figures, and may be configured to have two or more protrusions. The protrusions may be configured with one protrusion.

[0032] The configurations shown in the above embodiments are merely examples, and may be combined with other known techniques or may be combined with other embodiments. In addition, it is also possible to omit or modify a part of the configuration without departing from the scope of the present invention. [Explanation of symbols]

[0033] 1 stator, 2 rotor, 3 shaft, 4 rotor core, 5 end ring, 6 balance weight, 50, 51, 52, 53 protrusions, 50a, 50b, 50c convex portions, 60 cylindrical portion, 61 holding portion, 100 electric motor.

Claims

1. A rotor core fixed to the shaft that serves as the axis of rotation, The rotor core comprises an end ring provided at at least one end of the rotor core in the rotation axis direction of the shaft, The end ring provided at least one end of the rotor core has a plurality of protrusions that extend in the direction of the rotation axis of the shaft. The aforementioned projections are provided in at least two directions along the radial direction from the rotation center of the shaft, and at least two directions along the circumferential direction of concentric circles centered on the rotation center. The plurality of protrusions provided radially from the center of rotation of the shaft are arranged such that the product of the distance from the center of rotation to the axis of each protrusion and its weight is equal to each other. Each of the aforementioned protrusions is removable to adjust the rotational balance, and is configured to allow the attachment of a balance weight to increase the end ring's capacity to adjust the rotational balance. A rotor characterized by the following features.

2. The balance weight attached to the projection has a cylindrical body portion with an inner shape that fits onto the projection, and a holding portion that holds the cylindrical body portion in the state of being fitted onto the projection. The rotor according to feature 1.

3. Each of the aforementioned protrusions is formed by a plurality of convex portions with different outer shapes, such that the outer shape gradually decreases in size along the rotation axis of the shaft. The rotor according to feature 1 or 2.

4. A cylindrical stator, The rotor, as described in claim 1 or 2, is surrounded by the stator and rotated, and comprises An electric motor characterized by the following features.

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