US4394594A — Motor with a disk rotor

Claim 1

Independent Claim 135 words

Brushless d.c. motor comprising a multipolar permanent magnet rotor having at least 6 poles, 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; 254,255; 254',255'; 296,297) 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)·180 electrical degrees between centers, where n is a low positive integer.

Claim 2

Dependent Claim 135 words

Brushless d.c. motor comprising a multipolar permanent magnet rotor having at least 6 poles, 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; 254,255; 254',255'; 296,297) 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)·180 electrical degrees between centers, where n is a low positive integer.

Claim 3

Dependent Claim 29 words

Brushless d.c. motor as defined in claim 1, in which each said coil has a center-to center spacing of (180m+90) electrical degrees, where m is a low positive integer.

Claim 4

Dependent Claim 69 words

Brushless d.c. motor as defined in claim 1 in which said winding arrangement comprises at least one set of four coils, of which the first coil has a center spacing of 270 electrical degrees from the second coil, the second coil has a center spacing of 270 electrical degrees from the third coil, and the third coil has a center spacing of 270 electrical degrees from the fourth coil.

Claim 5

Dependent Claim 31 words

Brushless d.c. motor as defined in claim 1, in which each said coil has a center-to-center spacing of 450 electrical degrees from the coils on either side of it in sequence.

Claim 6

Dependent Claim 36 words

Brushless d.c. motor as defined in claim 1 in which said rotor has six poles and in which said stator means winding arrangement comprises four coils placed around the motor periphery with 90° mechanical angular spacing.

Claim 7

Dependent Claim 107 words

Brushless d.c. motor as defined in claim 1 in which the number of poles of said rotor is a multiple of 8, and in which said stator means comprises four coils, of which the center of the first is spaced 270 electrical degrees from the center of the second, which is in turn spaced 270 electrical degrees from the center of the third, which is in turn spaced 270 electrical degrees from the center of the fourth, and in which said sensors are located between said first and fourth coils, respectively at 180 and at 90 electrical degrees from the center of the first of said coils.

Claim 8

Dependent Claim 15 words

Brushless d.c. motor as defined in claim 1 in which said rotor has 10 poles.

Claim 9

Dependent Claim 46 words

Brushless d.c. motor as defined in claim 7 in which said stator means has four coils of which the first is spaced 270 electrical degrees from the second and the second 630 electrical degrees from the third, and the thrid 270 electrical degrees from the fourth.

Claim 10

Dependent Claim 31 words

Brushless d.c. motor as defined in claim 7 in which said stator means have four coils equally spaced around the rotor shaft at a spacing in succession of 450 electrical degrees.

Claim 11

Dependent Claim 15 words

Brushless d.c. motor as defined in claim 1 in which said rotor has 12 poles.

Claim 12

Dependent Claim 31 words

Brushless d.c. motor as defined in claim 10 in which said stator means have eight coils with an electrical spacing between centers from one to the next of 270 electrical degrees.

Claim 13

Dependent Claim 35 words

Brushless d.c. motor as defined in claim 10 in which said stator means have four coils equally sapced around the rotor shaft with an electrical spacing from one to the next of 450 electrical degrees.

Claim 14

Dependent Claim 15 words

Brushless d.c. motor as defined in claim 1 in which said rotor has 14 poles.

Claim 15

Dependent Claim 16 words

Brushless d.c. motor as defined in claim 13 in which said stator means has 8 coils.

Claim 16

Dependent Claim 16 words

Brushless d.c. motor as defined in claim 13 in which said stator means has 4 coils.

Claim 17

Dependent Claim 176 words

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-S4), rotor positions sensing means (76,77; 254,255; 254',255'; 296,297) 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.

Claim 18

Dependent Claim 176 words

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-S4), rotor positions sensing means (76,77; 254,255; 254',255'; 296,297) 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.

Claim 19

Dependent Claim 65 words

Brushless d.c. motor as defined in claim 1 or 16 in which said motor has a flat airgap, said winding is a flat one-layer winding extending into said airgap, and a tachogenerator arranged to be driven by said rotor is provided in the vicinity of said motor and comprises at least one measuring coil disposed for having voltages induced therein during operation of said motor.

Claim 20

Dependent Claim 60 words

Brushless d.c. motor as defined in claim 17, in which said tachogenerator (34) has a measuring coil (42) and also a second coil (43) substantially identical with said measuring coil (42) connected in a series opposing relation with said measuring coil and in which said second coil (43) is not linked with the useful flux passing through the measuring coil.

Claim 21

Dependent Claim 26 words

Brushless d.c. motor as defined in claim 17, in which magnetic shielding of sheet metal (33) is provided between the motor portion and the tachogenerator (34).

Claim 22

Dependent Claim 37 words

Brushless d.c. motor as defined in claim 17, in which the coils (59) of the stator winding are in each case adhesively bonded by an adhesive (125) to the stator casing (12) by their respective outer sides.

Claim 23

Dependent Claim 25 words

Brushless d.c. motor as defined in claim 1 or 16 in which the width of said individual coils is substantially greater than 180 electrical degrees.

Claim 24

Dependent Claim 46 words

Brushless d.c. motor as defined in claim 10, in whihc there is provided in a sector between two stator coils (57,60) a carrier member (75) extending into the airgap of the rotor (20), on which carrier member at least one rotor position sensor (76,77) is mounted.

Claim 25

Dependent Claim 37 words

Brushless d.c. motor as defined in claim 1 or 16 in which the coils are wound as bifilar coils, the two wires of the coils of a set being connected to form two phase windings per set.

Claim 26

Dependent Claim 175 words

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 four individual coils affixed to the motor casing at their radially outer portions so that said coils extend self-supportedly into said air gap, of which coils the first has a center-to-center spacing of 270 electrical degrees from the second, the second likewise from the third, and the third likewise from the fourth, 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).

Claim 27

Dependent Claim 175 words

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 four individual coils affixed to the motor casing at their radially outer portions so that said coils extend self-supportedly into said air gap, of which coils the first has a center-to-center spacing of 270 electrical degrees from the second, the second likewise from the third, and the third likewise from the fourth, 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).

Claim 28

Dependent Claim 50 words

Brushless d.c. motor as defined in claim 1, 16 or 24, in which a first and the third coils in circumferential sequence form a pair of one set of coils and are serially connected and oppositely wound and likewise the second and fourth coils forming the other set of coils.

Claim 29

Dependent Claim 34 words

Brushless d.c. motor as defined in claim 1, 16 or 24, in which each said coil has a center-to-center spacing of 270 electrical degrees from the coils on either side of it in sequence.

Claim 30

Dependent Claim 211 words

Low-speed brushless d.c. motor comprising a substantially disk-shaped permanent magnet rotor mounted on a shaft, magnetic return path means substantially parallel to the disk plane of said rotor defining a flat air gap between said rotor and said return path means, an iron-free stator winding predominantly located in said air gap and a tachogenerator coaxial with said shaft on the opposite side of said return path means from said rotor, said tachogenerator comprising a speed measuring coil (42) through which said shaft passes coaxially thereto, means for causing a magnetic flux varying at a rate dependent on the speed of the motor to be linked through said speed measuring coil for inducing an alternating voltage therein of a frequency dependent upon motor speed and a compensation coil (43) coaxial with said shaft and with said speed measuring coil mounted so as to be substantially uninfluenced by the flux of said magnetic flux which varies at a rate dependent on motor speed and so mounted as to be linked by the same stray flux as is linked through said speed measuring coil, said compensation coil being connected so as to superpose its output on the output of said speed measuring coil for reducing the effects of stray flux on the combined output.

Claim 31

Dependent Claim 211 words

Low-speed brushless d.c. motor comprising a substantially disk-shaped permanent magnet rotor mounted on a shaft, magnetic return path means substantially parallel to the disk plane of said rotor defining a flat air gap between said rotor and said return path means, an iron-free stator winding predominantly located in said air gap and a tachogenerator coaxial with said shaft on the opposite side of said return path means from said rotor, said tachogenerator comprising a speed measuring coil (42) through which said shaft passes coaxially thereto, means for causing a magnetic flux varying at a rate dependent on the speed of the motor to be linked through said speed measuring coil for inducing an alternating voltage therein of a frequency dependent upon motor speed and a compensation coil (43) coaxial with said shaft and with said speed measuring coil mounted so as to be substantially uninfluenced by the flux of said magnetic flux which varies at a rate dependent on motor speed and so mounted as to be linked by the same stray flux as is linked through said speed measuring coil, said compensation coil being connected so as to superpose its output on the output of said speed measuring coil for reducing the effects of stray flux on the combined output.

Claim 32

Dependent Claim 33 words

Brushless d.c. motor as defined in claim 27 in which said speed measuring and compensation coils are connected together in series in bucking relation with respect to voltages induced by said stray flux.

Claim 33

Dependent Claim 21 words

Brushless d.c. motor as defined in claim 28 in which said speed measuring and compensation coils are of substantially identical construction.

Claim 34

Dependent Claim 45 words

Brushless d.c. motor as defined in claim 27, 28 or 29 in which said measuring and compensation coils are flat coils of a thickness much smaller than their radius and are located with a flat surface of one near a flat surface of the other.

Claim 35

Dependent Claim 34 words

Brushless d.c. motor as defined in claim 30 in which said measuring and compensation coils are on opposite sides of a stationary member (35) forming a portion of the magnetic path of said tachogenerator.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-07-18	1987-01-17	1987-07-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-07-18	1991-01-17	1991-07-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-07-18	1995-01-17	1995-07-19	$7700.00	Window Closed / Lapsed

Motor with a disk rotor

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