Servo motor with high energy product magnets
AssigneeKollmorgen Corporation
InventorsRoy D. Schultz, Thomas R. England, A. Clark Altizer
Life of this patent
Estimating the term…
Abstract
A dynamoelectric machine having a large magnetic gap between the rotor and the stator includes a slotless stator windings located within the large magnetic gap, and a mgnetic assembly consisting of radially aligned permanent magnets separated by non-magnetic material. The magnetic pole circumferential length and the radial gap length are proportioned such that the permanent magnets are operated at or near their maximum energy product.
Claims18
A dynamoelectric machine operating near the maximum energy point and having a high resistance to demagnetization and low roll-off to enable a high peak torque, comprising:
- a permanent magnet rotor including a plurality of radially extending NdFeB permanent magnets providing pole faces separated by a non-magnetic medium, and each magnet having an energy product in excess of 30 MGOe;
- a slotless cylindrical outer stator shell of magnetic material defining an air gap between said magnets and said stator shell;
- an insulated wire winding secured to the inside surface of said stator shell;
- and
- an encapsulating resin for impregnating said insulated wire winding to secure said winding to said slotless stator shell and, for withstanding the maximum torque force throughout the range of operating temperatures;
- wherein said energy product and a ratio of the spacing between said pole faces to said air gap enable the machine to operate near the maximum energy point, have a high resistance to demagnetization and have low roll-offs for enabling a high peak torque.
A dynamoelectric machine comprising:
- a rotor including a plurality of radially extending permanent magnets providing pole faces separated by a non-magnetic medium each having an energy product in excess of 26 MGOe;
- a slotless cylindrical outer stator shell of magnetic material defining an air gap between said magnets and said stator shell;
- the ratio of the interpolar spacing between adjacent pole faces, Lig, and the air gap length, Lg, being at least 1.3;
- the ratio of the length of said permanent magnets to the radial length of said air gap being in the range 0.5 to 2.0;
- and
- a multi-phase winding in said air gap secured to the inner surface of said cylindrical stator shell.
A dynamoelectric machine comprising:
- a rotor including a plurality of radially extending permanent magnets providing pole faces separated by a non-magnetic medium and each having an energy product in excess of 26 MGOe;
- a slotless cylindrical outer stator shell of magnetic material defining an air gap between said magnets and said stator shell;
- the ratio of the interpolar spacing between adjacent pole faces, Lip, and the air gap length, Lg, being at least 1.3;
- and
- a multi-phase winding in said air gap secured to the inner surface of said cylindrical stator shell.
A dynamoelectric machine operating near the maximum energy point and having a high resistance to demagnetization and low roll-offs to enable a high peak torque comprising:
- a rotor including a plurality of radially extending permanent magnets providing pole faces separated by a non-magnetic medium, and each magnet having an energy product in excess of 30 MGOe;
- a slotless cylindrical outer stator shell of magnetic material defining an air gap between said magnets and said stator shell;
- the ratio of the interpolar spacing of non-magnetic material between adjacent pole faces, Lip, and the air gap length, Lg, being at least 1.3;
- and a multi-phase winding in said air gap secured to the inner surface of said cylindrical stator shell;
- wherein said energy product and said ratio enable the machine to operate near the maximum energy point, have a high resistance to demagnetization and low roll-offs for enabling a high peak torque.
A dynamoelectric machine operating near the maximum energy point and having a high resistance to demagnetization and low roll-offs to enable a high peak torque comprising:
- a rotor including a plurality of radially extending permanent magnets providing pole faces separated by a non-magnetic medium, each magnet having an energy product in excess of 30 MGOe;
- a slotless cylindrical outer stator shell of magnetic material defining an air gap between said magnets and said stator shell;
- the ratio of the interpolar spacing between adjacent pole faces, Lip, and the air gap, length, Lg, being at least 1.3;
- the ratio of the length of said permanent magnets to the radial length of said air gap being in the range 0.5 to 2.0;
- and
- a multi-phase winding in said air gap secured to the inner surface of said cylindrical stator shell;
- wherein said energy product and said ratio enable the machine to operate near the maximum energy point, have a high resistance to demagnetization and low roll-offs for enabling a high peak torque.
Dependencies are inferred from the claim text.