JP-7855606-B2 - Rotor for permanent magnet electromachines

JP7855606B2JP 7855606 B2JP7855606 B2JP 7855606B2JP-7855606-B2

Inventors

アソレイ・ブラスケス・アンヘル

Assignees

イクイップメイク・リミテッド

Dates

Publication Date: 20260508
Application Date: 20220405
Priority Date: 20210409

Claims (5)

A rotor for a permanent magnet electromachine, A hub having a central rotation reference axis, A first and second set of rotor segments, wherein the first set extends around the circumferential surface of the hub at an axial position different from that of the second set, Each segment, At least one permanent magnet, wherein the permanent magnet of the first set is offset circumferentially from the permanent magnet of the second set, It includes an engaging portion formed to mechanically engage with the hub to resist radial forces and having a central axis extending radially in a plane perpendicular to the central rotation reference axis, In each rotor segment of the first set, the center of mass of the magnet is offset circumferentially from the central axis of the respective engagement portion. A rotor in which the segments are shaped such that the center of mass of each segment is substantially aligned with the central axis of each of the engaging portions.
The rotor according to claim 1, wherein the radially extending sidewalls of each rotor segment of the first set are asymmetrical with respect to the radial line extending through the center of mass of the magnet in a cross-section perpendicular to the central rotation reference axis.
The rotor according to claim 1 or 2, wherein each rotor segment of the first set overlaps with an adjacent segment of the first set in the circumferential direction.
The rotor according to any one of claims 1 to 3, wherein each rotor segment of the first set extends partway down the adjacent segment of the first set in the circumferential direction.
Each rotor segment of the first set includes a pair of permanent magnets, Each of the pair of permanent magnets has, in a cross-section extending perpendicular to the central rotation reference axis, an elongated shape, with an inner end closer to the center of mass of the segment than to the outer end, and the inner end is inclined to be closer to the central rotation reference axis. The rotor according to any one of claims 1 to 4, wherein each rotor segment of the first set extends at least partway down the permanent magnet of the adjacent segment in the circumferential direction.

Description

This disclosure relates to a rotor for a permanent magnet electromachine. More specifically, it relates to the configuration of the rotor segments of the rotor. A rotor for a permanent magnet electromachine, such as a motor or generator, may include a central hub comprising a set of permanent magnets and rotor segments arranged around their outer circumference. Because such rotors may operate at very high rotational speeds, they must be designed to reliably hold the magnets and segments in place against high centrifugal and magnetic forces. This is a top perspective view of a rotor for a permanent magnet electromachine.This is a cross-sectional view of the upper part of the rotor shown in Figure 1.This is a cross-sectional view of the upper part of the rotor shown in Figure 1.This is a cross-sectional view of the upper part of the rotor shown in Figure 1.This is a cross-sectional view of the upper part of a rotor according to one embodiment of the present disclosure.This is a cross-sectional view of the upper part of a rotor according to one embodiment of the present disclosure. Figures 1 to 4 show the upper part of the rotor 2, including two adjacent sets of rotor segments 4 and 6. The rotor segments are supported on the outer circumferential surface 8 of the rotor hub 10. The hub 10 is formed by machining a solid piece of material, using an additive manufacturing process, or preferably by casting. The hub 10 may be made of, for example, steel or aluminum. Each set of segments is arranged in a ring around the hub, with one set axially displaced relative to the other in the rotational reference axis of the hub. The segments may be formed, for example, from laminated steel sheets. Each rotor segment 12 includes a main body portion 14 and an engaging portion 16. The engaging portion is shaped to mechanically engage with the hub in order to resist the displacement of the segment relative to the hub due to radial forces acting on the segment. In the embodiments shown in Figures 1 to 4, each rotor segment includes an engaging portion in the form of a radially inwardly extending projection 16. In other configurations, the engaging portion may instead be in the form of a groove that receives an outwardly extending projection forming part of the hub 10. In Figures 1 to 4, the projection 16 is substantially dovetail-shaped in a plane extending perpendicular to the rotational reference axis of the hub. The projection is received in an axially extending groove 18 defined by the radially outward-facing circumferential surface of the rotor hub 10. The cross-sectional shape of the groove is substantially complementary to the cross-sectional shape of the projection 16. The groove extends linearly across the width of the hub in the axial direction and also receives projections from other sets (6) of segments. Each rotor segment may include a pair of magnets 20. Each magnet is held within a notch 22 defined by the main body portion 14 of its rotor segment. The magnets are spaced apart circumferentially and have their centers of mass located at the same distance from the central axis of the hub. Each magnet may be elongated when viewed in a cross-section perpendicular to the central rotation reference axis of the hub (as shown in Figures 1 and 2). Each magnet is inclined such that, when viewed in this plane, its inner end 21 (closer to the center of mass of the segment than its outer end 23) is closer to the center of the rotor hub than its outer end 23. In other implementations, each rotor segment may contain a single magnet or three or more magnets. As can be seen in Figure 2, each segment of one set 4 is configured such that the radial center reference line or axis 30 of the projection 16 of each segment is offset 34 circumferentially from the radial center reference line or axis 32 of the main body portion 14 of the segment. The radial axis 32 extends between a pair of magnets 20. The projection is symmetrical in a plane perpendicular to the rotor's axis of rotation with respect to its central axis 30. The main body portion 14 is symmetrical in that plane with respect to its central axis 32. This offset may also exist in the other set (6) of rotor segments shown in Figure 1, but on opposite sides circumferentially. In that configuration, the rotor segments of both sets may be identical, and in the assembled rotor, one set is reversed relative to the other. Each set is circumferentially offset or skewed relative to the other. The circumferential offset between the two sets of rotor segments serves to minimize the effect of cogging torque. However, in the rotor configured according to Figures 1 to 4, when the rotor rotates around its central axis, the mass centers of the segments are not aligned circumferentially with the central axis 30 of the projection 16. Therefore, the segments of set 4 experience a force that causes each segment to rotate relative to the rotor hub. This can lead to the formation of undesirable gaps b