Electric motor with combined permanent and electromagnets
First Claim
1. An electric motor comprising a first motor part and a second motor part (1, 2) which are rotatable relative to one another and each of which has a ferromagnetic core and which are separated by an air gap (6) lying between the ferromagnetic cores, wherein the ferromagnetic core of said first motor part (1) has provided on the surface thereof which faces the air gap (6) a plurality of salient magnetic poles which are disposed sequentially and in spaced relationship in the direction of rotation, and of which some are ferromagnetic (4) and some are permanent-magnetic (3) and all of which are magnetically connected to a magnetizing winding (5A, 5B) for simultaneous magnetization of both the ferromagnetic (4) and the permanent-magnetic (3) poles, wherein the ferromagnetic core of the said other motor part (2) is provided on the surface thereof facing the air gap (6) and opposite the magnetic poles (3, 4) on the core of the first part (1) with a row of salient ferromagnetic reluctance poles (7) which extend in said direction of rotation and which have a constant pole pitch and are spaced-apart equidistantly, wherein each such reluctance pole (7) over a portion thereof has a width in the direction of rotation which corresponds essentially to half said pole pitch and over the remaining portion thereof is smaller such that each reluctance pole (7) has a part (7B) which projects in a predetermined direction common to all reluctance poles (7), wherein the ferromagnetic and permanent-magnetic poles (3, 4) on the core the first motor part (1) have a width in the direction of rotation which corresponds essentially to the width of the narrow part of the reluctance poles (7) and are so positioned that during relative rotation of the two motor parts (1, 2), all ferromagnetic poles (4) will be located simultaneously opposite their respective reluctance poles (7) on the second motor part (2) and, similarly, such that all permanent-magnetic poles (3) will be simultaneously located opposite their respective reluctance poles (7), wherein the number of permanent-magnetic poles (3) is smaller than the number of reluctance poles (7) on the core of the second motor part (2), such that no permanent-magnetic poles (3) are present in some of those positions which would be occupied by such permanent-magnetic poles if a number of permanent-magnetic poles (3) equal to the number of reluctance poles (7) of the core of the second motor part (2) were distributed uniformly.
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Accused Products
Abstract
A rotary electric motor has a stator core (1) with salient poles (4, 3), some of them ferromagnetic and some of them permanent-magnetic, which are spaced-apart and which are all simultaneously magnetizable by means of a magnetizing winding (5A, 5B). The rotor core has either reluctance poles (7) with intervening pole gaps and constant pole pitch, or permanent-magnetic poles (10) with constant pole pitch and without intervening pole gaps, alternating poles being of opposite polarities. Each reluctance pole (7) or permanent-magnetic pole (10) has a width which over a portion of the pole corresponds to respectively one-half of or the full pole pitch and is smaller over the remaining portion so that each pole (7 or 10) has a part (7B or 10A) which projects in a direction common to all poles. The ferromagnetic and permanent-magnetic poles (3, 4) of the stator (1) have a width corresponding to the width of the narrower portion of the poles (7 or 10) of the rotor (2). The number of permanent-magnetic poles (3) and, optionally, also the number of ferromagnetic poles (4) of the stator (1) is smaller than the number of reluctance poles (7) or permanent-magnetic poles (10) of the rotor (2), the positioning of the poles being such that when the motor is running, all ferromagnetic stator poles (4) will be simultaneously positioned opposite respective rotor poles (7 or 10) and all permanent-magnetic stator poles (30 likewise are simultaneously positioned opposite respective rotor poles (7 or 10).
41 Citations
20 Claims
- 1. An electric motor comprising a first motor part and a second motor part (1, 2) which are rotatable relative to one another and each of which has a ferromagnetic core and which are separated by an air gap (6) lying between the ferromagnetic cores, wherein the ferromagnetic core of said first motor part (1) has provided on the surface thereof which faces the air gap (6) a plurality of salient magnetic poles which are disposed sequentially and in spaced relationship in the direction of rotation, and of which some are ferromagnetic (4) and some are permanent-magnetic (3) and all of which are magnetically connected to a magnetizing winding (5A, 5B) for simultaneous magnetization of both the ferromagnetic (4) and the permanent-magnetic (3) poles, wherein the ferromagnetic core of the said other motor part (2) is provided on the surface thereof facing the air gap (6) and opposite the magnetic poles (3, 4) on the core of the first part (1) with a row of salient ferromagnetic reluctance poles (7) which extend in said direction of rotation and which have a constant pole pitch and are spaced-apart equidistantly, wherein each such reluctance pole (7) over a portion thereof has a width in the direction of rotation which corresponds essentially to half said pole pitch and over the remaining portion thereof is smaller such that each reluctance pole (7) has a part (7B) which projects in a predetermined direction common to all reluctance poles (7), wherein the ferromagnetic and permanent-magnetic poles (3, 4) on the core the first motor part (1) have a width in the direction of rotation which corresponds essentially to the width of the narrow part of the reluctance poles (7) and are so positioned that during relative rotation of the two motor parts (1, 2), all ferromagnetic poles (4) will be located simultaneously opposite their respective reluctance poles (7) on the second motor part (2) and, similarly, such that all permanent-magnetic poles (3) will be simultaneously located opposite their respective reluctance poles (7), wherein the number of permanent-magnetic poles (3) is smaller than the number of reluctance poles (7) on the core of the second motor part (2), such that no permanent-magnetic poles (3) are present in some of those positions which would be occupied by such permanent-magnetic poles if a number of permanent-magnetic poles (3) equal to the number of reluctance poles (7) of the core of the second motor part (2) were distributed uniformly.
Specification