Electric motor, particularly a brushless direct current motor
First Claim
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1. An electric motor, particularly a brushless direct current motor, comprising:
- a stator and a rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means;
a rotor shaft supporting said rotor and mounted for common rotation therewith;
bearing means rotatingly mounting said rotor shaft;
stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft and having an outer facing peripheral wall, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator having an inner facing wall and being mounted on the outside of said bearing support means and being supported thereby, the inner facing wall of the stator facing the outer facing wall of the bearing support means;
said stator wall and said bearing support means wall being separated from one another over at least a substantial portion of their facing faces by a second air gap defined therebetween which extends also over a substantial portion of the axial length of said stator iron means; and
elastic damping means connecting said stator to said bearing support means.
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Abstract
Electric motor with a substantially cylindrical air gap between the stator and the rotor, the stator being fitted to a bearing support for the rotor shaft bearing. In order to reduce noise emissions, the stator is connected to the bearing support by means of an elastic damper and the stator and bearing support are separated from one another by an air gap adjacent at least part of their facing faces.
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Citations
24 Claims
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1. An electric motor, particularly a brushless direct current motor, comprising:
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a stator and a rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means; a rotor shaft supporting said rotor and mounted for common rotation therewith; bearing means rotatingly mounting said rotor shaft; stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft and having an outer facing peripheral wall, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator having an inner facing wall and being mounted on the outside of said bearing support means and being supported thereby, the inner facing wall of the stator facing the outer facing wall of the bearing support means; said stator wall and said bearing support means wall being separated from one another over at least a substantial portion of their facing faces by a second air gap defined therebetween which extends also over a substantial portion of the axial length of said stator iron means; and elastic damping means connecting said stator to said bearing support means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electric motor, particularly a brushless direct current motor, comprising
a stator and a rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means; -
a rotor shaft supporting said rotor and mounted for common rotation therewith; bearing means rotatingly mounting said rotor shaft; stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft and having an outer facing peripheral wall, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator having an inner facing wall and being mounted on the outside of said bearing support means and being supported thereby, the inner facing wall of the stator facing the outer facing wall of the bearing support means; said stator wall and said bearing support means wall being separated from one another over at least a substantial portion of their facing faces by a second air gap defined therebetween which extends also over a substantial portion of the axial length of said stator iron means. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An electric motor, particularly a brushless direct current motor, comprising
a stator and rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means; -
a rotor shaft supporting said rotor and mounted for common rotation therewith; bearing means rotatingly mounting said rotor shaft; stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator being mounted on the outside of said bearing support means and being supported thereby; said bearing means including first and second ball bearings with a different number of balls disposed circumferentially in the first bearing as compared to the number of balls disposed circumferentially in the second bearing.
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22. An electric motor, particularly a brushless direct current motor, comprising
a stator and a rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means; -
a rotor shaft supporting said rotor and mounted for common rotation therewith; bearing means rotatingly mounting said rotor shaft; stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft and having an outer facing peripheral wall, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator having an inner facing wall and being mounted on the outside of said bearing support means and being supported thereby, the inner facing wall of the stator facing the outer facing wall of the bearing support means; said stator wall and said bearing support means wall being separated from one another over at least a substantial portion of their facing faces by a second air gap defined therebetween which extends also over a substantial portion of the axial length of said stator iron means; said rotor being constructed as an external rotor with a substantially cup-shaped rotor casing having openings distributed over the closed end of the cup-shaped casing.
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23. An electric motor, particularly a brushless direct current motor, comprising
a stator and a rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means; -
a rotor shaft supporting said rotor and mounted for common rotation therewith; bearing means rotatingly mounting said rotor shaft; stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft and having an outer facing peripheral wall, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator having an inner facing wall and being mounted on the outside of said bearing support means and being supported thereby, the inner facing wall of the stator facing the outer facing wall of the bearing support means; said stator wall and said bearing support means wall being separated from one another over at least a substantial portion of their facing faces by a second air gap defined therebetween which extends also over a substantial portion of the axial length of said stator iron means; elastic damping means connecting said stator to said bearing support means; said rotor being constructed as an external rotor with a substantially cup-shaped rotor casing having openings distributed over the closed end of the cup-shaped casing.
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24. An electric motor, particularly a brushless direct current motor, comprising
a stator and a rotor which define a substantially cylindrical air gap therebetween, said stator including stator iron means and a coil creating an electromagnetic field when energized, said rotor mounting a permanent magnet ring, electromagnetic forces acting between the rotor and the stator when the coil is energized; -
a rotor shaft supporting said rotor and mounted for common rotation therewith; bearing means rotatingly mounting said rotor shaft; stationary, substantially tubular bearing support means disposed in coaxial relationship to said rotor shaft, said bearing means being mounted inside of said bearing support means and being supported thereby, said stator being mounted on the outside of said bearing support means and being supported thereby; the magnetic components of the rotor and stator being arranged symmetrically to one another whereby the sum of the magnetic axial forces between the rotor and stator are minimized for noise reduction purposes.
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Specification