PERMANENT MAGNET ROTOR ELECTRIC MOTOR

• US 3,845,339 A
• Filed: 08/31/1972
• Issued: 10/29/1974
• Est. Priority Date: 09/01/1971
• Status: Expired due to Term

• Current Assignee: Alfred Merkle, Fritz Schmieder, Werner Heinzmann
• Original Assignee: Alfred Merkle, Fritz Schmieder, Werner Heinzmann
• Inventors: Merkle, Alfred, Schmieder, Fritz, Heinzmann, Werner
• Primary Examiner(s): Duggan, D. F.
• Application Number:
  US05/285,520
• Time in Patent Office: 789 Days
• Field of Search: 310/68,67,268,156 318/132,138,254
• US Class Current: 310/156.34
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02K 3/46 Fastening of windings on the stator or rotor structure

Abstract

An electric motor, particulary a collectorless D.C. motor, has a stator including a support portion having a passage and a generally plate-shaped winding arrangement fixedly mounted on the support portion and surrounding the passage. The rotor includes a rotatable motor shaft extending through the passage and a plurality of axially polarized magnets mounted on said shaft for rotation therewith and axially spaced from the winding arrangement and defining therewith an axial air gap.

Claims

1. A collectorless DC motor for driving signal recording devices and signal reproducing devices, comprising, in combination, a stator comprising a central support portion provided with a mounting passage, an outwardly extending mounting member for mounting the motor on a structural support, and an axial bearing portion, said stator additionally comprising a generally plateshaped winding arrangement fixedly mounted on said support portion and surrounding said passage;

a rotor comprising a rotor shaft extending through said passage transversely through said winding arrangement so as to be encircled by the latter and having an end bearing axially upon said axial bearing portion, an axially polarized permanent magnet arrangement encircling said shaft, said winding arrangement and said magnet arrangement having facing first axial sides axially spaced to define a first axial air gap and having opposite second axial sides, a first magnetic return structure encircling said shaft and located adjacent said second axial side of said magnet arrangement, and a second magnetic return structure encircling said shaft and located adjacent to said second axial side of said winding arrangement axially spaced from the latter to define therewith a second axial air gap, said magnetic arrangement and said first and second magnetic return structures being mounted on said shaft for rotation therewith and connected together at the radially outer portions thereof; and

output means connected with said shaft at a portion of said shaft axially spaced from said magnetic arrangement and said return structures and operative for transmitting driving force from said rotor shaft to a device to be driven by said motor.

2. A motor as defined in claim 1, wherein said support portion comprises a hollow generally cylindrical support body provided with said outwardly extending mounting member and further provided with axially extending radial bearing means for radially supporting said winding arrangement, said mounting member being located at one axial end of said cylindrical support body.

3. A motor as defined in claim 2, wherein said central support portion is provided with an interior chamber having an axial end wall constituting said axial bearing portion, and wherein said output means comprises an output drive gear mounted on said rotor shaft for rotation therewith and located in said interior chamber.

4. A motor as defined in claim 3, wherein said axial bearing portion is axially adjustable.

5. A motor as defined in claim 1, wherein said winding arrangement comprises a plurality of windings arranged in a ring around said shaft, each of said windings being comprised of coils lying in planes generally transverse to the elongation of said shaft, and the overall adjustment of windings having a generally disc-like shape.

6. A motor as defined in claim 5, wherein said winding arrangement is comprised of a non-magnetic carrier arrangement of generally annular disc-shaped configuration having an inner periphery mounted on said support portion and a plurality of radially extending ribs connected together at their radially innermost ends and at their radially outermost ends and holding said windings in position on said carrier arrangement.

7. A motor as defined in claim 6, wherein said plurality of windings comprise a first plurality of windings located at one axial side of said carrier arrangement in a first general plane and a second plurality of windings located at the other side of said carrier arrangement in a second general plane, said first and said second Plurality of windings being each arranged in a ring around said shaft, and wherein said retaining ribs lie in first and second planes in correspondence to the respective planes of said windings, and wherein said retaining ribs further have widened portions each serving to engage the inner periphery of a respective one of said windings.

8. A motor as defined in claim 7, wherein two of said widened portions additionally serve to each support at least one electronic component associated with control circuitry for the motor, and wherein said windings are energized by 90* out-of-phase currents, and wherein said two widened portions are associated with windings spaced apart by n times 360 plus 90 electrical degrees, where n is an integer including zero and one.

9. A motor as defined in claim 7, wherein at least one of said widened portions additionally serves to support at least one electronic component associated with control circuitry for the motor, and wherein said carrier arrangement includes a circuit board on the central portion of said carrier arrangement, said circuit board being provided with connections to said electronic component and carrying the terminals of said windings, and wherein said circuit board if furthermore provided with a printed circuit, and wherein said circuit board overlies the radially innermost portions of at least some of said windings.

10. A motor as defined in claim 5, wherein at least some of said windings are formed of two distinct and separately energizable electrical conductors.

11. A motor as defined in claim 1, wherein said permanent magnet arrangement is comprised of a magnet ring comprised of ring sectors polarized axially in a first sense and alternating with ring sectors polarized axially in the opposite sense, and wherein at least one of said first and second magnetic return structures is held in place by the force of magnetic attraction of said magnet ring.

12. A motor as defined in claim 1, wherein said rotor comprises a generally cup-shaped ferromagnetic member at least a portion of which constitutes said first magnetic return structure, and wherein said permanent magnets are supported directly on the axial side of said cup-shaped member which faces said winding arrangement, and wherein said second magnetic return structure is maintained in centered position by the rim portion of said cup-shaped member.

13. In an electric motor, particularly a collectorless DC motor, in combination, a stator comprising a support portion having a passage and a generally plate-shaped winding arrangement fixedly mounted on said support portion and surrounding said passage;

and a rotor comprising a rotatable motor shaft extending through said passage and a plurality of axially polarized magnets mounted on said shaft for rotation therewith and axially spaced from said winding arrangement and defining therewith an axial air gap, wherein said winding arrangement is generally disc-shaped and includes a carrier arrangement of generally annular disc-shaped configuration, and a first plurality of windings carried on said carrier arrangement and located at one axial side thereof in a second general plane, each of said plurality of windings being arranged in a ring around said shaft, and each of said windings being comprised of coils lying in planes generally transverse to the elongation of said shaft, and said carrier arrangement having retaining means for retaining said pluralities of windings in the respective planes, wherein said retaining means comprises a plurality of radially extending retaining ribs, and wherein said retaining ribs lie in first and second planes in correspondence to the respective planes of said windings, and wherein said retaining ribs further have widened portions each serving to engage the inner periphery of a respective one of said windings, and wherein two of said widened portions additionally serve to each support at least one electronic component associated with control circuiTry for the motor, and wherein said windings are energized by 90* out-of-phase currents, and wherein said two widened portions are associated with windings spaced apart by n times 360 plus 90 electrical degrees, where n is an integer including zero and one.

14. A collectorless DC motor for driving signal recording devices and signal reproducing devices, comprising, in combination, a stator comprising a central support portion provided with a mounting passage and an axial bearing portion, said stator additionally comprising a generally plate-shaped winding arrangement fixedly mounted on said support portion and surrounding said passage;

and a rotor comprising a rotor shaft extending through said passage transversely through said winding arrangement so as to be encircled by the latter and having an end bearing axially upon said axial bearing portion, an axially polarized permanent magnet arrangement encircling said shaft, said winding arrangement and said magnet arrangement having facing first axial sides axially spaced to define a first axial air gap and having opposite second axial sides, a first magnetic return structure encircling said shaft and located adjacent said second axial side of said magnet arrangement, and a second magnetic return structure encircling said shaft and located adjacent to said second axial side of said winding arrangement axially spaced from the latter to define therewith a second axial air gap, said magnetic arrangement and said first and second magnetic return structures being mounted on said shaft for rotation therewith and connected together at the radially outer portions thereof.