# US 7,608,962 B2 · Electrical machine and method for setting the field and armature of a permanently excited electrical machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,962 B2 - Document ID: US7608962B2 - Status: Granted - Kind: B2 - Application number: 11/868,020 - Filed: 2007-10-05 - Published: 2008-02-14 - Granted: 2009-10-27 - Earliest claimed: 2005-04-06 - Assignees: Bayerische Motoren Werke Aktiengesellschaft - Inventors: Torsten Franke - Web page: https://patentgrep.com/patent/US7608962B2 ## CPC - H02K 16/02: Machines with one stator and two {or more} rotors - H02K 2213/06: Machines characterised by the presence of fail safe, back up, redundant or other similar emergency arrangements - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract Electrical machine, having a stator which bears a winding and having a rotatable rotor, situated at a distance from the stator via an air gap, which includes at least two coaxial rotor sections which are rotatable relative to one another, in which each rotor section bears a system of permanent magnets having polarities which alternately point outward radially, and having an actuating device for rotating the rotor sections relative to one another, the actuating device having a controllable actuator via which the rotor sections may be aligned with one another with a variable rotary offset which is independent of a rotational speed of the rotor. In a method for setting the field and armature of a permanently energized electrical machine for motor vehicles, the rotational speed range of the electrical machine is divided into an armature-setting range, and a freely preselected field suppression is associated with a particular rotational speed of the rotor. ## Claims ### Claim 1 An electrical machine, comprising: a stator which bears a winding; a rotatable rotor, situated at a distance from the stator via an air gap, the rotor including at least two coaxial rotor sections which are rotatable relative to one another, in which each rotor section bears a system of permanent magnets having polarities which point outward radially in alternation; and an actuating device for rotating the rotor sections relative to one another; wherein the actuating device has a controllable actuator configured to align the rotor sections with one another with a variable rotary offset which is independent of a rotational speed of the rotor; and wherein the rotor sections are provided on shaft sections of a main shaft designed as a hollow shaft, in which an inner shaft is supported in an axially displaceable manner, and the actuator is designed as a displacement element for axial displacement of the inner shaft which, in mechanical linkage with a mutually engaged guide situated on the shafts, provides a freely selectable rotation and alignment of the rotor sections with respect to one another. ### Claim 2 (depends on 1) The electrical machine according to claim 1, wherein the first rotor section is rigidly connected to the main shaft, and the second rotor section is mounted so as to be rotatable relative to the main shaft. ### Claim 3 (depends on 1) The electrical machine according to claim 1, wherein the rotor sections are supported so as to be rotatable relative to the main shaft, and the inner shaft has a guide groove by means of which a rotational alignment of the axially displaceable inner shaft with respect to the outer main shaft may be fixed. ### Claim 4 (depends on 1) The electrical machine according to claim 1, wherein the rotor has more than two rotor sections which are rotatable relative to one another. ### Claim 5 (depends on 4) The electrical machine according to claim 4, wherein every other rotor section is rigidly connected to the other. ### Claim 6 (depends on 1) The electrical machine according to claim 1, wherein the actuator is designed as a hydraulic piston which may be actuated via the fluid pressure of a motor vehicle transmission. ### Claim 7 (depends on 1) The electrical machine according to claim 1, wherein the actuator is designed as an electrical actuator which acts on an adjustment aid provided on the inner shaft. ### Claim 8 (depends on 1) The electrical machine according to claim 1, wherein the actuator may be controlled via a centrifugal force regulator which conforms to the rotational speed of the main shaft of the rotor. ### Claim 9 (depends on 1) The electrical machine according to claim 1, wherein a guide at an inner shaft is designed as at least one of axially and helically extending guide grooves, and a guide at a main shaft is designed as a guide catch which engages with the guide grooves. ### Claim 10 (depends on 9) The electrical machine according to claim 9, wherein the guide grooves have different slopes in places. ### Claim 11 (depends on 9) The electrical machine according to claim 9, wherein the guide grooves are oppositely sloped in places. ### Claim 12 (depends on 9) The electrical machine according to claim 9, wherein the rate of slope of the guide grooves within a shaft section of the inner shaft is changeable. ### Claim 13 (depends on 9) The electrical machine according to claims 9, wherein the guide grooves provided with at least one of different slopes and progressions overlap one another. ### Claim 14 (depends on 1) The electrical machine according claim 1, wherein the rotor has spring elements that support the rotor sections relative to one another, and a preferred state of the rotational position of the rotor sections may be set by adapting the elastic force of the spring elements to the rotationally acting magnetic forces which occur between the rotor sections during operation. ### Claim 15 (depends on 1) The electrical machine according to claim 1, wherein the rotor sections are designed as intermeshed cups.