Rotor and electric motor

Abstract

To obtain a rotor which does not require press-fitting a balance ring, and the balance of which can be easily readjusted.SOLUTION: A rotor 10 comprises a shaft 1, a rotor core 2 fixed to around the shaft 1, and a pair of balance rings 30a, 30b that is secured to the shaft 1. The balance rings 30a, 30b have ring parts 3a, 3b exhibiting an annular shape having openings 5a, 5b where a section in the circumferential direction is absent from the outer diameter through to the inner diameter, and have jig holes 6a, 6b at both ends of the rings parts 3a, 3b which an auxiliary jig is inserted into, and are secured to the shaft 1 by grasping the shaft 1. The interval in the circumferential direction of the openings 5a, 5b is expanded by the auxiliary jig inserted into the jig holes 6a, 6b, and the fixation of the balance rings 30a, 30b to the shaft 1 is released.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] In the balance adjustment of the rotor of an electric motor, after measuring the phase angle and the amount of unbalance, the mainstream methods are the incremental method of applying paste or attaching weights to cancel the unbalance, or the decremental method of machining a part of the rotor.

[0003] In Patent Document 1, two disk-shaped balance rings with intentionally induced unbalance are overlapped and press-fitted onto the shaft of the rotor, and the unbalance is canceled by the resultant vector of the balance rings. One disk-shaped balance ring is a plate material composed of a long-radius semi-circular portion having a shaft hole at the center and a short-radius semi-circular portion having a shaft hole at the center. By adjusting the overlapping angle between the first plate material and the second plate material, the balance adjustment is performed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, since the balance ring is press-fitted onto the shaft, if the balance cannot be achieved due to an angular error during press-fitting or the like, readjustment is difficult and the rotor has to be discarded.

[0006] The present disclosure has been made in view of the above, and an object thereof is to obtain a rotor that does not require press-fitting of a balance ring and enables easy readjustment of the balance.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, the rotor of the present disclosure includes a rotor shaft, a rotor core fixed around the rotor shaft, and a pair of balance rings disposed on at least one of the axial directions of the rotor core and fixed to the rotor shaft. The pair of balance rings has a ring portion having an annular shape with an opening in which a part in the circumferential direction is missing from the outer diameter to the inner diameter, has a first hole into which an auxiliary tool is inserted at both ends of the ring portion, and is fixed to the rotor shaft by gripping the rotor shaft. The circumferential interval of the opening is widened by the auxiliary tool inserted into the first hole, and the fixing of the pair of balance rings to the rotor shaft is released.

Effect of the Invention

[0008] According to the rotor of the present disclosure, there is an effect that press-fitting of the balance ring is not required and readjustment of the balance can be easily performed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 4

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Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0010] Hereinafter, the rotor and the electric motor according to the embodiment will be described in detail with reference to the drawings.

[0011] Embodiment 1. FIG. 1 is a front cross-sectional view showing the configuration of the rotor 10 according to Embodiment 1. FIG. 2 is a side cross-sectional view showing the configuration of the rotor 10 according to Embodiment 1. An electric motor is constituted by the rotor 10 and a stator (not shown).

[0012] As shown in FIGS. 1 and 2, the rotor 10 includes a shaft 1 as a rotor shaft, a rotor core 2 as a rotor iron core, and balance rings 30a and 30b. The balance rings may be fixed in two or more on at least one of the load side and the non-load side of the shaft 1. In the first embodiment, as a desirable configuration, the balance rings include a total of four balance rings 30a and 30b, two on each of the load side and the non-load side of the shaft 1. The balance ring 30b as the second balance ring is fitted onto the shaft 1 so as to contact the side surface which is the axial end surface of the rotor core 2. The balance ring 30a as the first balance ring has a smaller diameter than the balance ring 30b and is fitted onto the shaft 1 so as to contact the side surface of the balance ring 30b.

[0013] The balance rings 30a and 30b have a weight imbalance (eccentric center of gravity) in the rotational direction. By changing the rotational angles of the two balance rings 30a and 30b with respect to the shaft 1, the imbalance amount and the phase angle of the imbalance by the combined imbalance vector are adjusted.

[0014] The balance rings 30a and 30b have ring portions 3a and 3b having an annular shape in which shaft holes 4a and 4b into which the shaft 1 is fitted are formed, and openings 5a and 5b in which a part in the circumferential direction is missing from the outer diameter to the inner diameter. The ring portion 3a of the balance ring 30a corresponds to the first ring portion, and the ring portion 3b of the balance ring 30b corresponds to the second ring portion. The ring portions 3a and 3b of the balance rings 30a and 30b are formed of an elastic metal. The shaft hole 4a and the opening 5a are continuous, and the shaft hole 4b and the opening 5b are continuous. The inner diameters of the balance rings 30a and 30b, that is, the diameters of the shaft holes 4a and 4b of the balance rings 30a and 30b are configured to be slightly smaller than the outer diameter of the shaft 1. The balance rings 30a and 30b are fixed to the shaft 1 by gripping the shaft 1 by the gripping force of the ring portions 3a and 3b.

[0015] On the outer surface of the ring portion 3a of the balance ring 30a, jig holes 6a are provided as a pair of first holes into which an auxiliary tool (not shown), which is a jig or a tool, is inserted. The jig holes 6a are provided near the end of the ring portion 3a and are holes extending in the axial direction. On the outer surface of the ring portion 3b of the balance ring 30b, a pair of jig holes 6b into which the auxiliary tool is inserted are provided. The jig holes 6b are provided near the end of the ring portion 3b. The outer diameter of the ring portion 3a is set such that it is on a circumference smaller than the position of the jig hole 6b of the balance ring 30b.

[0016] By inserting the auxiliary tool into the jig holes 6a and 6b and opening the ring portions 3a and 3b with the auxiliary tool, the circumferential interval between the openings 5a and 5b of the ring portions 3a and 3b can be widened. Thereby, the inner diameters of the ring portions 3a and 3b, that is, the diameters of the shaft holes 4a and 4b, can be temporarily made larger than the outer diameter of the shaft 1. Also, after widening the inner diameters of the ring portions 3a and 3b of the balance rings 30a and 30b with the auxiliary tool, by removing the auxiliary tool from the balance rings 30a and 30b, they return to their original inner diameters due to elastic deformation. Thereby, the shaft 1 is gripped again by the ring portions 3a and 3b, and the balance rings 30a and 30b are fixed to the shaft 1.

[0017] In this way, by widening the inner diameters of the ring portions 3a and 3b of the balance rings 30a and 30b with the auxiliary tool, passing them over the outer diameter of the shaft 1, and then removing the auxiliary tool from the balance rings 30a and 30b, the inner diameters of the ring portions 3a and 3b become smaller due to the elastic deformation of the balance rings 30a and 30b and fit onto the shaft 1. Then, it is fixed to the shaft 1 by the gripping force due to the elastic force of the ring portions 3a and 3b.

[0018] Even after the balance rings 30a and 30b are fixed to the shaft 1 once, the inner diameter can be widened again with the auxiliary tool, and the fixed position in the rotational direction can be changed any number of times.

[0019] As described above, the outer diameter of the ring portion 3a of the balance ring 30a is on a circumference smaller than the position of the jig hole 6b of the balance ring 30b, and regardless of the rotation direction of the balance rings 30a and 30b, a jig can be inserted into the jig holes 6a and 6b of all the balance rings 30a and 30b from the axial direction. With this configuration, the rotation angle of the balance rings 30a and 30b can be adjusted from one direction, facilitating the balance adjustment work.

[0020] Thus, in the first embodiment, the balance rings 30a and 30b have ring portions 3a and 3b having an annular shape with openings 5a and 5b where a part in the circumferential direction is missing from the outer diameter to the inner diameter. The balance rings 30a and 30b have jig holes 6a and 6b into which auxiliary tools are inserted at both ends of the ring portions 3a and 3b. The balance rings 30a and 30b are fixed to the shaft 1 by gripping the shaft 1, and the circumferential interval of the openings 5a and 5b of the ring portions 3a and 3b is widened by the auxiliary tools inserted into the jig holes 6a and 6b to release the fixing of the balance rings 30a and 30b to the shaft 1. Therefore, press-fitting of the balance ring is not required, and balance readjustment can be easily performed.

[0021] Second Embodiment. FIG. 3 is a front cross-sectional view showing the configuration of the rotor 11 according to the second embodiment. FIG. 4 is a side cross-sectional view showing the configuration of the rotor 11 according to the second embodiment. In the rotor 11 of the second embodiment, end plates 7 are added to the rotor 10 of the first embodiment.

[0022] The end plates 7 are provided on both the load side and the counter-load side, which are both sides of the rotor core 2, to prevent the rotor core 2 from protruding in the axial direction. The end plates 7 have shaft holes 7a through which the shaft 1 passes. The end plates 7 are fitted and fixed to the outer diameter of the shaft 1 together with the rotor core 2.

[0023] In Embodiment 2, the balance rings 30a and 30b are fitted into the outer diameter of the end plate 7. Similar to Embodiment 1, the balance rings 30a and 30b have ring portions 3a and 3b which are in an annular shape and in which shaft holes 4a and 4b into which the shaft 1 is fitted are formed, and openings 5a and 5b in which a part in the circumferential direction is lacking from the outer diameter to the inner diameter. The ring portion 3a of the balance ring 30a corresponds to the first ring portion, and the ring portion 3b of the balance ring 30b corresponds to the second ring portion. The ring portions 3a and 3b of the balance rings 30a and 30b are formed of an elastic metal. The shaft hole 4a and the opening 5a are continuous, and the shaft hole 4b and the opening 5b are continuous. The inner diameter of the balance rings 30a and 30b, that is, the diameters of the shaft holes 4a and 4b of the balance rings 30a and 30b are configured to be slightly smaller than the outer diameter of the end plate 7. The balance rings 30a and 30b are fixed to the shaft 1 by gripping the end plate 7 by the gripping force of the ring portions 3a and 3b.

[0024] On the outer surfaces of the ring portions 3a and 3b of the balance rings 30a and 30b, a pair of jig holes 6a and 6b into which an auxiliary tool can be inserted are provided. The jig hole 6b is provided near the end of the ring portion 3b. The outer diameter of the ring portion 3a is set such that it is on a circumference smaller than the position of the jig hole 6b of the balance ring 30b.

[0025] After widening the inner diameters of the ring portions 3a and 3b of the balance rings 30a and 30b with an auxiliary tool and passing them through the outer diameter of the end plate 7, by removing the auxiliary tool from the balance rings 30a and 30b, the inner diameters of the ring portions 3a and 3b become smaller due to the elastic deformation of the balance rings 30a and 30b and fit onto the end plate 7. Then, it is fixed to the end plate 7 by the gripping force due to the elastic force of the ring portions 3a and 3b.

[0026] FIG. 5 is a front cross-sectional view showing a configuration of a modified example of the rotor 11 according to Embodiment 2. FIG. 6 is a side cross-sectional view showing a configuration of an end plate 7' used in the modified example of the rotor 11 according to Embodiment 2. In this modified example, the end plate 7' has a main body portion 7d into which balance rings 30a and 30b are fitted, and a flange portion 7e having a diameter larger than that of the main body portion 7d. The flange portion 7e can prevent the balance rings 30a and 30b from moving in the axial direction.

[0027] As described above, in the end plate 7' of the modified example, a step is provided between the main body portion 7d and the flange portion 7e, facilitating the axial positioning of the balance rings 30a and 30b, reducing the error during balance adjustment, and enabling the reduction of the balance adjustment time.

[0028] Thus, according to Embodiment 2, the balance rings 30a and 30b have ring portions 3a and 3b having an annular shape with openings 5a and 5b where a part in the circumferential direction is missing from the outer diameter to the inner diameter, and jig holes 6a and 6b into which auxiliary tools are inserted at both ends of the ring portions 3a and 3b. By gripping the end plates 7 and 7', they are fixed to the end plates 7 and 7', and the circumferential interval of the openings 5a and 5b of the ring portions 3a and 3b is widened by the auxiliary tools inserted into the jig holes 6a and 6b to release the fixing of the balance rings 30a and 30b to the end plates 7 and 7'. Therefore, the movement of the rotor core 2 can be blocked, the press-fitting of the balance rings becomes unnecessary, and the balance can be easily readjusted.

[0029] Embodiment 3. FIG. 7 is a side view showing a configuration of one of the balance rings 30a used in the rotor according to Embodiment 3. FIG. 8 is a side view showing a configuration of the other balance ring 30b used in the rotor according to Embodiment 3. FIG. 9 is a side view showing a state where two balance rings used in the rotor according to Embodiment 3 are overlapped.

[0030] In Embodiment 3, as shown in FIGS. 7 to 9, the balance rings 30a and 30b have shaft holes 4a and 4b with the same diameter, and have ring portions 3a and 3b in an annular shape with the same inner diameter and outer diameter. The ring portions 3a and 3b of the balance rings 30a and 30b have openings 5a and 5b in which a part of the circumferential direction of the annular shape is missing, and are formed of an elastic metal. In FIGS. 7 to 9, the end plates 7 shown in Embodiment 2 are fitted into the shaft holes 4a and 4b of the balance rings 30a and 30b. The inner diameter of the ring portions 3a and 3b, that is, the diameter of the shaft holes 4a and 4b of the ring portions 3a and 3b, is configured to be slightly smaller than the outer diameter of the end plate 7. In Embodiment 3, the shaft 1 may be fitted into the shaft holes 4a and 4b of the balance rings 30a and 30b.

[0031] As shown in FIG. 7, near both ends of the ring portion 3a of the balance ring 30a, a pair of jig holes 6a into which an auxiliary tool can be inserted are provided. As shown in FIG. 8, at both ends of the ring portion 3b of the balance ring 30b, extending portions 8 extending radially outward from the ring portion 3b are provided. A pair of jig holes 6b into which an auxiliary tool can be inserted are provided in each of the extending portions 8.

[0032] Thus, in Embodiment 3, the balance rings 30a and 30b having the ring portions 3a and 3b with the same inner diameter and outer diameter are prepared. The jig holes 6b of one balance ring 30b are provided outside the outer diameter of the ring portion 3b, and the outer diameter of the ring portion 3a and the jig holes 6a of the other balance ring 30a are provided on the inner diameter side with respect to the position of the jig holes 6b of the balance ring 30b. Therefore, the rotational directions of both balance rings 30a and 30b can be easily changed with an auxiliary tool from the axial direction.

[0033] Embodiment 4. FIG. 10 is a side cross-sectional view showing the configuration of one balance ring 30a used for the rotor according to Embodiment 4. FIG. 11 is a top view showing the configuration of one balance ring 30a used for the rotor according to Embodiment 4. The balance ring 30a has an annular ring portion 3a having a shaft hole 4a into which the shaft 1 or the end plate 7 is fitted, and an opening 5a with a part in the circumferential direction missing.

[0034] In Embodiment 4, a jig hole 6a extending in the radial direction is provided near the end of the circumferential surface of the ring portion 3a of the balance ring 30a. For this reason, the auxiliary tool is accessed from the outer diameter side toward the inner diameter side. Regarding the other balance ring 30b, although not shown, a jig hole 6b extending in the radial direction is provided near the end of the circumferential surface of the ring portion 3b of the balance ring 30b.

[0035] The configuration of providing the jig holes 6a and 6b in the circumferential surfaces of the ring portions 3a and 3b in Embodiment 4 can be applied to any of the configurations of fixing the ring portions 3a and 3b with different outer diameters shown in Embodiment 1 to the shaft 1, the configuration of fixing the ring portions 3a and 3b with different outer diameters shown in Embodiment 2 to the end plate 7, and the configuration of fixing the ring portions 3a and 3b with the same outer diameter shown in Embodiment 3 to the shaft 1 or the end plate 7.

[0036] According to Embodiment 4, since the jig holes 6a and 6b are provided in the outer peripheral surfaces of the balance rings 30a and 30b, the balance can be adjusted by accessing the auxiliary tool from the outer diameter direction, and the workability is improved. Also, if the balance rings 30a and 30b have the same outer diameter, the types of balance rings can be reduced, and management becomes easier.

[0037] Embodiment 5. FIG. 12 is a front view showing the configuration of the shaft 1 used for the rotor according to Embodiment 5. In Embodiment 5, grooves 1a are provided at one location each on the load side and the non-load side of the shaft 1, and the aforementioned balance rings 30a and 30b are fitted into the grooves 1a. The configuration of providing the grooves 1a into which the balance rings 30a and 30b are fitted, as shown in Embodiment 5, can be applied to any of the previous Embodiments 1 to 4.

[0038] According to Embodiment 5, since the grooves 1a are provided in the shaft 1, the balance rings 30a and 30b can be positioned in the axial direction, the error during balance adjustment can be reduced, and the time for balance adjustment can be shortened.

[0039] Embodiment 6. FIG. 13 is a front cross-sectional view showing the configuration of the rotor 10 according to Embodiment 6. FIG. 14 is a side cross-sectional view showing the configuration of the balance rings 30a and 30b of the rotor 10 according to Embodiment 6. FIG. 15 is a side cross-sectional view showing the configuration of the shaft 1 of the rotor 10 according to Embodiment 6. In Embodiment 6, uneven portions 20 are provided on the outer periphery of the shaft 1, and uneven portions 9a and 9b are provided on the inner peripheries of the ring portions 3a and 3b of the balance rings 30a and 30b. The uneven portion 20 and the uneven portions 9a and 9b can be fitted together.

[0040] As shown in FIGS. 13 and 15, uneven portions 20 are provided on the outer periphery at the axial position where the balance rings 30a and 30b of the shaft 1 are fitted. The uneven portion 20 is a plurality of periodic unevenness along the circumferential direction of the outer periphery of the shaft 1. In FIG. 15, the portion where the rotor core 2 of the shaft 1 is fixed is shown outside the uneven portion 20, and the portions at both ends of the shaft 1 are shown inside the uneven portion 20.

[0041] As shown in FIG. 14, concavo-convex portions 9a are provided on the inner circumference of the ring portion 3a of the balance ring 30a. Also, concavo-convex portions 9b are provided on the inner circumference of the ring portion 3b of the balance ring 30b. The concavo-convex portions 9a and 9b are a plurality of periodic concavo-convex portions along the circumferential direction of the inner circumferences of the balance rings 30a and 30b. The balance rings 30a and 30b have openings 5a and 5b and jig holes 6a and 6b.

[0042] According to Embodiment 6, since the concavo-convex portions 20 are provided on the outer circumference of the shaft 1 and the concavo-convex portions 9a and 9b are provided on the inner circumferences of the ring portions 3a and 3b of the balance rings 30a and 30b, when positioning the balance rings 30a and 30b in the rotational direction, the rotational angle can be adjusted by angles corresponding to the formation period of the concavo-convex portions. Thereby, an error in the rotational direction can be reduced during balance adjustment, and the number of times of balance adjustment can be decreased.

[0043] Note that the concavo-convex portions 20 may be provided on the outer circumference of the end plate 7, and the concavo-convex portions 9a and 9b may be provided on the inner circumferences of the ring portions 3a and 3b of the balance rings 30a and 30b. Also, Embodiment 6 may be applied to any of the previous Embodiments 1 to 5.

[0044] The configurations shown in the above embodiments are examples of the content of the present disclosure, and it is possible to combine them with other known techniques, the configurations of the respective embodiments may be appropriately combined, and it is also possible to omit or change a part of the configuration without departing from the gist of the present disclosure.

Description of Reference Numerals

[0045] 1 Shaft, 1a Groove, 2 Rotor Core, 3a, 3b Ring Portion, 4a, 4b, 7a Shaft Hole, 5a, 5b Opening, 6a, 6b Jig Hole, 7, 7' End Plate, 7d Body Portion, 7e Flange Portion, 8 Extending Portion, 9a, 9b, 20 Concavo-Convex Portion, 10, 11 Rotor, 30a, 30b Balance Ring.

Claims

1. A rotor shaft, a rotor core fixed around the rotor shaft, a pair of balance rings disposed on at least one of the axial directions of the rotor core and fixed to the rotor shaft, comprising: the pair of balance rings has a ring portion presenting an annular shape having an opening with a part in the circumferential direction lacking from the outer diameter to the inner diameter, has first holes into which an auxiliary tool is inserted at both ends of the ring portion, and is fixed to the rotor shaft by gripping the rotor shaft, the circumferential interval of the opening is widened by the auxiliary tool inserted into the first hole, and the fixing of the pair of balance rings to the rotor shaft is released characterized in that it is a rotor.

2. A rotor shaft, a rotor core fixed around the rotor shaft, end plates provided on both sides of the rotor core and fixed around the rotor shaft, a pair of balance rings disposed on at least one of the axial directions of the rotor core and fixed to the end plates, comprising: the pair of balance rings has a ring portion presenting an annular shape having an opening with a part in the circumferential direction lacking from the outer diameter to the inner diameter, has first holes into which an auxiliary tool is inserted at both ends of the ring portion, and is fixed to the end plate by gripping the outer diameter of the end plate, the auxiliary tool is inserted into the first hole, the circumferential interval of the opening is widened, and the fixing of the pair of balance rings to the end plate is released characterized in that it is a rotor.

3. The pair of balance rings includes a first balance ring having a first ring portion and a second balance ring having a second ring portion with a larger outer diameter than the first ring portion, the second ring portion is arranged to be sandwiched between the rotor core and the first ring portion characterized in that it is the rotor according to Claim 1 or 2.

4. The first hole of the first ring portion is an axially extending hole formed in the outer end face in the axial direction of the first ring portion, and the first hole of the second ring portion is an axially extending hole formed in the outer end face in the axial direction of the second ring portion characterized in that it is the rotor according to Claim 3.

5. The first hole of the first ring portion is a radially extending hole formed in the outer peripheral surface of the first ring portion, and the first hole of the second ring portion is a radially extending hole formed in the outer peripheral surface of the second ring portion characterized in that it is the rotor according to Claim 4.

6. The pair of balance rings includes a first balance ring having a first ring portion and a second balance ring having a second ring portion having the same shape as the first ring portion. The second ring portion is disposed so as to be sandwiched between the rotor core and the first ring portion. The rotor according to claim 1 or 2, characterized in that.

7. The second balance ring has an extending portion extending radially outward from an end portion of the second ring portion. The first hole of the first ring portion is an axially extending hole formed in an axially outer end surface of the first ring portion, and the first hole of the second ring portion is an axially extending hole formed in an axially outer end surface of the extending portion. The rotor according to claim 6, characterized in that.

8. The first hole of the first ring portion is a radially extending hole formed in an outer peripheral surface of the first ring portion, and the first hole of the second ring portion is a radially extending hole formed in an outer peripheral surface of the second ring portion. The rotor according to claim 6, characterized in that.

9. An uneven portion is provided on an inner circumference of the ring portion of the pair of balance rings, and an uneven portion that fits into the uneven portion is provided on an outer circumference of the rotor shaft. The rotor according to claim 1, characterized in that.

10. An uneven portion is provided on an inner circumference of the ring portion of the pair of balance rings, and an uneven portion that fits into the uneven portion is provided on an outer circumference of the end plate. The rotor according to claim 2, characterized in that.

11. The rotor shaft has a groove to which the pair of balance rings is fixed. The rotor according to claim 1, characterized in that.

12. The end plate has a flange portion, and the end plate is fixed so as to sandwich the flange portion, the rotor core, and the pair of balance rings in the axial direction. The rotor according to claim 2, characterized in that.

13. A rotor shaft, A rotor core fixed around the rotor shaft, A pair of balance rings disposed on at least one of the axial directions of the rotor core and fixed to the rotor shaft, Comprising, The pair of balance rings has a ring portion having an annular shape with an opening in which a part in the circumferential direction is missing from the outer diameter to the inner diameter, has a first hole into which an auxiliary tool is inserted at both ends of the ring portion, and is fixed to the rotor shaft by gripping the rotor shaft. The rotor characterized by that.

14. A rotor shaft, A rotor core fixed around the rotor shaft, End plates provided on both sides of the rotor core and fixed around the rotor shaft, A pair of balance rings disposed on at least one of the axial directions of the rotor core and fixed to the end plates, Comprising: The pair of balance rings has a ring portion having an annular shape with an opening in which a part of the circumferential direction is missing from the outer diameter to the inner diameter, and has a first hole into which an auxiliary tool is inserted at both ends of the ring portion, and is fixed to the end plate by gripping the outer diameter of the end plate A rotor characterized by the above.

15. A rotor according to claim 1 or 2, A stator, An electric motor characterized by comprising:

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