US-20260128627-A1 - Rotor for a Permanently Excited Electric Machine Comprising a Multipart Rotor Laminated Core and Bandage, Permanently Excited Electric Machine, and Method for Producing a Rotor

US20260128627A1US 20260128627 A1US20260128627 A1US 20260128627A1US-20260128627-A1

Abstract

A rotor includes a permanent magnet arrangement having permanent magnets for exciting a magnetic rotor flux, and a rotor laminated core for holding and channelling the flux and including axial magnet pockets distributed in the circumferential direction and in which the permanent magnets are arranged. The rotor laminated core includes a core partial laminated core that has first receiving regions for the permanent magnets distributed in the circumferential direction, and segment partial laminated cores are arranged on the outside of the core partial laminated core distributed in the circumferential direction and that, on an inside thereof, each have a second receiving region for the permanent magnets, wherein a first and second receiving region form a magnet pocket, and the rotor has a bandage surrounding the core for frictionally connecting segment partial laminated cores to the core partial laminated core, which at least temporarily contact one another in the connected state.

Inventors

Markus Lang
Robert Schmidt

Assignees

BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT

Dates

Publication Date: 20260507
Application Date: 20231120
Priority Date: 20221221

Claims (14)

1 - 13 . (canceled)
14 . A rotor for a permanently excited electric machine comprising: an embedded permanent magnet arrangement comprising a plurality of permanent magnets configured to excite a magnetic rotor flux; and a rotor laminated core configured to retain and direct the magnetic rotor flux of the permanent magnet arrangement and comprising a plurality of axial magnet pockets that are arranged in a state distributed in a circumferential direction and in which the permanent magnets are arranged, wherein the rotor laminated core is configured in a plurality of pieces comprising: a core partial laminated core that, at an outer side, comprises a plurality of first receiving regions that are arranged in a state distributed in the circumferential direction for the permanent magnets, and a plurality of segment partial laminated cores that are arranged in a state distributed in the circumferential direction at the outer side of the core partial laminated core, and that, at an inner side in each case, have at least one second receiving region for the permanent magnets, wherein a first and a second receiving region in each case form a magnet pocket, and wherein the rotor has a bandage that surrounds the plurality of pieces of the rotor laminated core for non-positive-locking connection of the segment partial laminated cores to the core partial laminated core, wherein the core laminated core and the segment partial laminated cores touch each other at least temporarily in a connected state.
15 . The rotor according to claim 14 , wherein the bandage comprises a fiber-reinforced plastics material.
16 . The rotor according to claim 14 , wherein the core partial laminated core comprises, per rotor pole, a first receiving region with two groove-like recesses that are arranged in a V-shape, and which with a V-shaped magnet pocket being formed per rotor pole are covered in each case by a segment partial laminated core.
17 . The rotor according to claim 16 , wherein the V-shaped magnet pockets are in a form of hollow spaces in which a region is configured without webs between the two permanent magnets in order to provide a cavity that reduces flux leakage.
18 . The rotor according to claim 14 , wherein the core partial laminated core is configured in a star-shape and has radially outwardly protruding core part-teeth that delimit the first receiving regions in the circumferential direction and on which the segment partial laminated cores are at least temporarily supported.
19 . The rotor according to claim 18 , wherein the segment partial laminated cores have, at an edge in each case, a radially inwardly protruding segment portion that is arranged on an upper face of the core part-teeth and which is supported radially on the core part-teeth.
20 . The rotor according to claim 19 , wherein the radially inwardly protruding segment portions of two adjacent segment partial laminated cores with a tangential gap being formed are arranged beside each other on the upper face of a core part-tooth, wherein an outer side of the rotor laminated core is formed by outer sides of the segment partial laminated cores and the tangential gaps form cavities reducing flux leakage.
21 . The rotor according to claim 18 , wherein the core part-teeth comprise, at both sides, resilient tangential webs that protrude in the circumferential direction, wherein the segment partial laminated cores have continuations that protrude tangentially at the edge, wherein the continuations are, in a connected state of the core partial laminated core and the segment partial laminated cores with a radial gap being formed, arranged in a radially overlapping manner with the resilient tangential webs, and wherein the resilient tangential webs are, with flexible flux webs being formed, arranged by centrifugal-force-related radial redirection, arranged in abutment against the continuations, and consequently close the radial gap at least temporarily and at least in areas.
22 . The rotor according to claim 21 , wherein an outer side of the rotor laminated core is formed by an outer side of the segment partial laminated cores and by upper faces of the core part-teeth.
23 . The rotor according to claim 14 , wherein the segment partial laminated cores comprise positioning elements comprising axially extending chamfers configured to position the segment partial laminated cores in a sleeve-like auxiliary assembly member.
24 . A permanently excited electric machine for a motor vehicle, comprising: a stator; and the rotor according to claim 14 , wherein the rotor is rotatably supported with respect to the stator.
25 . A method for producing a rotor, comprising: providing a core partial laminated core; providing a sleeve-like auxiliary assembly member; axially assembling the auxiliary assembly member and the core partial laminated core, wherein the sleeve-like auxiliary assembly member radially surrounds the core partial laminated core in an assembled state; positioning permanent magnets and the segment partial laminated cores on the core partial laminated core by axially introducing the permanent magnets and the segment partial laminated cores into the auxiliary assembly member; joining support and balancing disks at opposing end faces of the rotor laminated core; removing the auxiliary assembly member; and fitting a bandage to the rotor laminated core.
26 . The method according to claim 25 , wherein removing the auxiliary assembly member from the rotor laminated core and the fitting the bandage to the rotor laminated core are carried out simultaneously.

Description

BACKGROUND AND SUMMARY The invention relates to a rotor for a permanently excited electric machine. The rotor has an embedded permanent magnet arrangement having a plurality of permanent magnets for exciting a magnetic rotor flux and a rotor laminated core for retaining and directing the magnetic rotor flux of the permanent magnet arrangement. The rotor laminated core comprises a plurality of axial magnet pockets which are arranged in a state distributed in the circumferential direction and in which the permanent magnets are arranged. The invention further relates to a permanently excited electric machine and a method for producing the rotor. In this instance, interest is focused on permanently excited electric machines which are used in particular as traction machines for electrified motor vehicles, for example, electric or hybrid vehicles. Such permanently excited electric machines have a stator and a rotor which is rotatably supported with respect to the stator. The rotor has a rotor laminated core and a magnetic-flux-exciting permanent magnet arrangement. The permanent magnet arrangement may be an embedded or recessed permanent magnet arrangement in which the permanent magnets are arranged in axially extending magnet pockets of the rotor laminated core. The rotor laminated core is in this instance generally formed from a plurality of axially stacked, punched sheet metal slats. In order to form the magnet pockets for the permanent magnets, recesses are punched out of the sheet metal slats which when axially stacking the sheet metal slats are arranged in alignment with each other and in this instance form tunnel-like hollow spaces. In addition, additional recesses may be punched out of the sheet metal slats which, as a result of axial stacking and mechanical connection, for example, by bundling, of the sheet metal slats form air-filled cavities in the manner of hollow spaces. These cavities act as electromagnetic insulators and form flux direction portions in the rotor laminated core which are configured for selective direction of the magnetic rotor flux in the rotor laminated core and consequently are intended to reduce as far as possible or in the best case completely prevent undesirable dispersions and consequently losses in the rotor laminated core. In and adjacent to the cavities, there may be arranged in the rotor laminated cores web regions which have a very small cross section and act as so-called flux barriers. Often the minimum width of these webs, as a result of the material properties of the rotor laminated core, for example, a strength, in particular under loading with centrifugal force, and for production-related reasons, for example, as a result of the punching tool and the bundling process, is limited so that a compromise has to be made in this instance with regard to the function thereof as flux barriers. For this reason, in known rotor laminated cores material, for example, in the form of webs, is often provided at locations at which in accordance with an optimal electromagnetic configuration it should be avoided since it has a detrimental effect on performance behavior or a performance of the electric machine. An object of the present invention is to provide a high-performance, mechanically stable and electromagnetically improved, permanently excited electric machine. This object is achieved according to the invention by a rotor, a permanently excited electric machine and a method having the features according to the present disclosure. Advantageous embodiments of the invention are also set out in the description and the Figures. A rotor according to the invention for a permanently excited electric machine has an embedded permanent magnet arrangement having a plurality of permanent magnets for exciting a magnetic rotor flux. Furthermore, the rotor comprises a rotor laminated core for retaining and directing the magnetic rotor flux of the permanent magnet arrangement having a plurality of axial magnet pockets which are arranged in a state distributed in the circumferential direction and in which the permanent magnets are arranged. The rotor laminated core is configured in multiple pieces. To this end, the rotor laminated core has a core partial laminated core which at an outer side has a plurality of first receiving regions which are arranged in a state distributed in the circumferential direction for the permanent magnets. Furthermore, the rotor laminated core has a plurality of segment partial laminated cores which are arranged in a state distributed in the circumferential direction at the outer side of the core partial laminated core and which at an inner side in each case have at least one second receiving region for the permanent magnets. In this instance, a first and a second receiving region in each case form a magnet pocket. Furthermore, the rotor has a bandage which surrounds the multi-component rotor laminated core for non-positive-locking connection of the segment partial lami