Motor with a disk rotor
First Claim
1. Brushless d.c. motor having a substantially disk-shaped permanent magnet rotor mounted on a shaft, a flat air gap and an iron-free stator winding arrangement comprising coils affixed to the motor casing at their radially outer portions so that said coils extend self-supporting into said air gap, said rotor comprising spacing means (93) located radially inward of said stator winding arrangement and between rotor portions extending respectively on both sides of said stator winding arrangement for withstanding magnetically produced axial forces between said rotor portions, said motor casing (12) being substantially shell-shaped and arranged to surround at least part of said rotor, said spacing means (93) surrounding with an interposed clearance a tubular bearing means (13) firmly attached to said motor casing (12) for journalling the shaft (11) of said rotor, said spacing means (93) being mounted so as to rotate with said shaft (11).
2 Assignments
0 Petitions
Accused Products
Abstract
A cup-shaped shell with a re-entrant bearing member surrounds the rotor on the bottom side and has a rim which is substantially flush with the top of the rotor. On a balcony or shoulder in the outer portion of the shell, the coils of an iron-less stator winding are affixed by means of an adhesive so that they extend self-supportingly inwards into an air gap between two parts of the rotor that are spaced by a separator piece resisting the magnetic forces tending to attract the two parts of the rotor to each other, which member is mounted on the rotor shaft and surrounds, with an intermediate clearance, the re-entrant bushing of the casing. The casing has a downward tubular extension below its floor which together with a cap forms a chamber for a tachogenerator utilizing a toothed disk and a multi-pole rubber magnet for speed control of the motor in connection with a pair of Hall effect generators located between two of the stator coils of the motor and a transistor circuit for operating the motor as a brushless d.c. motor.
49 Citations
39 Claims
- 1. Brushless d.c. motor having a substantially disk-shaped permanent magnet rotor mounted on a shaft, a flat air gap and an iron-free stator winding arrangement comprising coils affixed to the motor casing at their radially outer portions so that said coils extend self-supporting into said air gap, said rotor comprising spacing means (93) located radially inward of said stator winding arrangement and between rotor portions extending respectively on both sides of said stator winding arrangement for withstanding magnetically produced axial forces between said rotor portions, said motor casing (12) being substantially shell-shaped and arranged to surround at least part of said rotor, said spacing means (93) surrounding with an interposed clearance a tubular bearing means (13) firmly attached to said motor casing (12) for journalling the shaft (11) of said rotor, said spacing means (93) being mounted so as to rotate with said shaft (11).
- 30. Brushless d.c. motor comprising a permanent magnet rotor having a number of poles integrally divisible by four, stator means comprising a plurality of ironless coils arranged in a one layer winding arrangement, said coils being connected to form a plurality of phase windings (122,S1-S4), rotor position sensing means (76,77) for controlling the currents in said phase windings so as to obtain four current pulses per rotor rotation angle of 360 electrical degrees and to create in operation a rotary magnetic field driving said permanent magnet rotor, said winding arrangement comprising two sets of coils, each set comprising at least one pair of coils electrically connected with each other and oppositely poled with respect to each other and spaced from each other by (2n+1) times 180 electrical degrees, where n is a low positive integer.
- 38. Brushless d.c. motor comprising a multipolar permanent magnet rotor, stator means having a plurality of ironless coils arranged in a one layer winding arrangement, said coils being connected to form a plurality of phase windings (122, S1 to S4), rotor position sensing means (76, 77) for controlling the currents in said phase windings so as to obtain four current pulses per rotor rotation angle of 360 electrical degrees and to create in operation a rotary magnetic field driving said permanent magnet rotor, said winding arrangement comprising at least one set of four coils, of which the first coil has a center distance of 270 electrical degrees from the second coil, the second coil has a center distance of 270 electrical degrees from the third coil, and the third coil has a center distance of 270 electrical degrees from the fourth coil, the first coil being electrically connected with the third coil and oppositely poled with respect to it, and the second coil being electrically connected with the fourth coil and being oppositely poled with respect to it.
Specification