EP0040484A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Brushless D.C. motors
Assignee: Rotron Inc
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Filing: 1981-05-01
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Granted: —
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Expires: 2001-05-01
Abstract
Abstract A brushless D.C. motor with a permanent magnet rotor (20) employs Hall switches (70) to effect commutation. The rotor magnets (50) are of a greater axial length than the stator laminations (40) and the Hall switches are mounted on a printed circuit panel (60) within the stator frame (12) so as to be actuated by the fringe flux from the portion of rotor magnets (50) extending beyond the stator laminations (40). The pole faces of the stator laminations are stepped to assure proper starting and direction of rotation. A voltage regulating circuit (106, 108, Q1) forming part of the commutating arrangement on the printed circuit panel enables the same circuit to be used for a range of stator energizing voltages. A switching circuit responsive to the analog output voltage of said Hall switches (70) provides a binary output voltage and includes transistors (Q3 and Q4) coupled to each stator winding (42a and 42b) and a transistor (Q2) responsive to the binary output of the Hall switches (70) for alternately switching the transistors (Q3 and Q4) to connect the stator windings (42a and 42b) to a D.C. power supply.
Inventors
- 👤 Wharton Mcdaniel
- 👤 Fred A. Brown
- 👤 Donald Thompson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 15:45
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
146 words
A brushless D.C. motor comprising: rotor means (20) including permanent magnet means (50) providing a pair of poles of opposite polarity, said rotor being arranged to rotate about a longitudinal axis; stator means (30) including a frame (12), a plurality of laminations (40) symmetrical about said axis supported on said frame and a I pair of windings (42) associated with said laminations; said permanent magnet means extending along and axially beyond said stator laminations; magnetic flux responsive means (70) exposed to magnetic flux from the portion of said magnet means extending beyond said stator laminations; characterized in that electronic circuit means (62) are coupled to said magnetic field responsive means (70) for alternately energizing said stator windings (42); and a support panel (60) is mounted on said frame (12), said magnetic flux responsive means (70) and said circuit means (62) being carried by said panel (60).
Claim 2
Dependent Claim
146 words
A brushless D.C. motor comprising: rotor means (20) including permanent magnet means (50) providing a pair of poles of opposite polarity, said rotor being arranged to rotate about a longitudinal axis; stator means (30) including a frame (12), a plurality of laminations (40) symmetrical about said axis supported on said frame and a I pair of windings (42) associated with said laminations; said permanent magnet means extending along and axially beyond said stator laminations; magnetic flux responsive means (70) exposed to magnetic flux from the portion of said magnet means extending beyond said stator laminations; characterized in that electronic circuit means (62) are coupled to said magnetic field responsive means (70) for alternately energizing said stator windings (42); and a support panel (60) is mounted on said frame (12), said magnetic flux responsive means (70) and said circuit means (62) being carried by said panel (60).
Claim 3
Dependent Claim
70 words
A brushless D.C. motor according to Claim 1, characterized in that said frame (12) is generally perpendicular to said axis adjacent one end of said rotor and stator means, and said frame includes an axially extending member (12a) for supporting said stator laminations (40) and associated windings (42), said support panel (60) being mounted on said member (12a) between said frame (12) and said stator laminations (4 0 ) .
Claim 4
Dependent Claim
63 words
A brushless D.C. motor according to Claim 2, characterized in that said panel'(60) is in the form of a circular disc having a central opening adapted to snugly engage said axially extending member (12a), said magnetic flux responsive means (70) being mounted on the surface of said panel facing said rotor means (20) and extending into proximity to said permanent magnet means (50).
Claim 5
Dependent Claim
56 words
A brushless D.C. motor according to any one of the preceding claims, characterized in that the poles of said permanent magnet means (50) are in the form of portions of a hollow cylinder concentric with said axis, and the stator laminations (40) are generally circular in shape and radially spaced inwardly of said permanent magnet means.
Claim 6
Dependent Claim
33 words
A brushless D.C. motor according to Claim 4, characterized in that said permanent magnet means (50) are carried by a cylinder (52) of magnetic flux conducting material which surrounds the permanent magnet means.
Claim 7
Dependent Claim
76 words
A brushless D.C. motor according to Claim 5, characterized in that the rotor means (20) further comprises a generally circular rotor hub (24), means (22) on said hub for supporting said magnetic flux conducting cylinder (52) and said permanent magnet means (50) in cantilever fashion from the inner surface of said hub, and a shaft (28) extending from said inner surface of said hub coaxially with said magnetic flux conducting cylinder and said permanent magnet means.
Claim 8
Dependent Claim
38 words
A brushless D.C. motor according to Claim 6, characterized in that an arbor (32) is provided through said stator laminations (40), and said shaft (28) extends through and is journalled in said arbor by means of bearings (34).
Claim 9
Dependent Claim
100 words
A brushless D.C. motor according to any one of the preceding claims characterized in that there is provided means for supplying D.C. power to said stator windings (42), said magnetic flux responsive means (70) and said circuit means (62) including: (a) a pair of terminals (100 and 101) for connection to a source of D.C. power; (b) a voltage divider circuit including variable resistance means (106, Ql) and voltage regulating means (108) connected in series between said terminals; and (c) means coupling the voltage across said voltage regulating means to said magnetic flux responsive means and to said circuit means.
Claim 10
Dependent Claim
71 words
A brushless D.C. motor according to Claim 8, characterized in that said magnetic flux responsive means comprises a pair of Hall effect switches (70), each of said switches including: (a) a Hall cell providing an output voltage which is an analog of the magnetic flux density to which it is exposed, and (b) a switching circuit responsive to the analog output-voltage of said Hall cell to provide a binary output voltage.
Claim 11
Dependent Claim
67 words
A brushless D.C. motor according to Claim 9, characterized in that said switching circuit means comprises: (a) transistor switching means (Q3 and Q4) coupled to each of said stator windings (42a and 42b), and (b) means (Q2) responsive to the binary output of said Hall effect.switches (70) for activating said transistor switching means (Q3 and Q4) for alternately coupling said windings to said D.C. power supply means.
Claim 12
Dependent Claim
47 words
A brushless D.C. motor of Claim 10, characterized in that said means for activating said transistor switching means (Q3 and Q4) includes voltage delay means in the form of an R-C circuit (116, 118 and 120, 122) for each of said transistor switching means (Q3 and Q4).
References Cited (Backward Citations)
No citation records indexed.
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