GB2329763A - A brushless motor with the upper pole edges and lower pole edges of the stator having different areas thus reducing vibration - Google Patents

A brushless motor with the upper pole edges and lower pole edges of the stator having different areas thus reducing vibration Download PDF

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Publication number
GB2329763A
GB2329763A GB9720643A GB9720643A GB2329763A GB 2329763 A GB2329763 A GB 2329763A GB 9720643 A GB9720643 A GB 9720643A GB 9720643 A GB9720643 A GB 9720643A GB 2329763 A GB2329763 A GB 2329763A
Authority
GB
United Kingdom
Prior art keywords
pole
brushless motor
winding
edges
mount
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9720643A
Other versions
GB9720643D0 (en
GB2329763B (en
Inventor
Alex Horng
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sunonwealth Electric Machine Industry Co Ltd
Original Assignee
Sunonwealth Electric Machine Industry Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sunonwealth Electric Machine Industry Co Ltd filed Critical Sunonwealth Electric Machine Industry Co Ltd
Priority to GB9720643A priority Critical patent/GB2329763B/en
Priority to DE29718710U priority patent/DE29718710U1/en
Priority to FR9712894A priority patent/FR2769766B3/en
Publication of GB9720643D0 publication Critical patent/GB9720643D0/en
Publication of GB2329763A publication Critical patent/GB2329763A/en
Application granted granted Critical
Publication of GB2329763B publication Critical patent/GB2329763B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/03—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/18—Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures
    • H02K1/187—Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures to inner stators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/22—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating around the armatures, e.g. flywheel magnetos

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Brushless Motors (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

A brushless motor having a base plate 1 on which is mounted an axial tube 13. A winding mount 2 , having a winding 21 and provided with two pole plate assemblies 3and4 is also mounted on the axial tube 13. A rotor 5 having a rotating shaft 52 is rotatably mounted in the axial tube 13, the rotor 5 being provided with an annular magnet 51. The pole plate assemblies 3and4 provided on the winding mount 2 comprise an upper pole plate assembly 3 mounted on an upper end of the mount, having a number of annularly spaced pole edges 31 and a lower pole plate assembly 4 mounted on a lower end of the mount, having a number of axially spaced pole edges 41. Each lower pole edge 41 has as area different from that of each upper pole edge 31 with the pole edges differing in either width fig.2 or height fig.3. The motor may act to reduce vibrations during operation thereby overcoming sudden torque.

Description

Brushless Motors with Reduced Vibrations Background of the Invention The present invention relates to brushless motors which have reduced vibrations during operation.
Brushless direct-current motors may be classified, according to the direction of the magnetic field generated by the magnets of the rotor, into three types: axial windings/axial air gaps, radial windings/radial air gaps, and axial windings/radial air gaps, wherein the direction of the magnetic field generated by the rotor of the motor having axial air gaps is parallel to a rotating axis of the motor, and the direction of the magnetic field generated by the rotor of the motor having radial air gaps is parallel to the rotating axis of the motor.
Motors with radial gaps are more popular as they have substantially closed magnetic paths and are thus suitable to serve as high torque motors. In addition, the winding machine for motors with radial air gaps has been widely used in automatic production, which further provides the motors with radial air gaps with advantages in the consideration of equipment cost and the economic effect.
Stators with radial teeth structures have been widely used in motors with axial windings and radial air gaps as such structures provide a good field loop and effectively reduce the leakage and are thus suitable to serve as high torque motors. Nevertheless, such motors, having a plurality of annularly spaced grooves for mounting windings thereon, are limited in miniaturization due to difficulty in the winding and less flexibility in different winding methods resulting from the distances between the grooves and the outlines and numbers of the grooves.
U.S. Patent No. 4,891,567 to Fujitani et al., filed on July 12, 1988 and issued on January 2, 1990, discloses a brushless DC motor of high performance, wherein the upper yoke and the lower yoke of the stator do not coincident on the same plane such that the detection points respectively on the upper and lower pole plates cannot be located on the same horizontal plane. Accordingly, vibrations and sudden rotations occur during rotation of the motor. In addition, the torque of the motor is relatively small.
The present invention is intended to provide improved brushless motors with high torque and high speed.
Summary of the Invention It is an object of the present invention to provide improved brushless motors which may reduce vibrations during operation to thereby overcome sudden torque. Thus, the motors provided by the present invention can serve as the motors with high torque and high speed which are suitable for CD-ROM drivers.
A brushless motor in accordance with the present invention comprises a base plate including an axial tube mounted thereon, a winding mount mounted around the axial tube and including a winding wound therearound, an upper pole plate assembly mounted on an upper end of the winding mount and including a plurality of annularly spaced upper pole edges, a lower pole plate assembly mounted on a lower end of the winding mount and including a plurality of annularly spaced lower pole edges, and a rotor including a rotating shaft rotatably received in the axial tube and an annular magnet mounted therein.
Each lower pole edge has an area different from that of each upper pole edge. The upper pole edge and the lower pole edge have either different widths or different heights.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Brief Description of the Drawings Fig. 1 is an exploded perspective view of a brushless motor in accordance with the present invention; Fig. 2 is a sectional view of a first embodiment of a brushless motor in accordance with the present invention; and Fig. 3 is a sectional view of a second embodiment of a brushless motor in accordance with the present invention.
Description of the Preferred Embodiments Referring to the drawings and initially to Fig. 1, a brushless motor in accordance with the present invention generally includes a base plate 1, a winding mount 2, an upper pole plate assembly 3, a lower pole plate assembly 4, and a rotor 5. The base plate 1 is, e.g., a circuit board having necessary electric control element(s) 11 mounted thereon. The base plate 1 further includes a hole 12 through which an axial tube 13 extends. The axial tube 13 includes a bearing 14 mounted therein for rotatably receiving a rotating shaft 52 of the rotor 5 which includes an annular magnet 51.
The winding mount 2 includes an upper end and a lower end for respectively mounting the upper pole plate assembly 3 and the lower pole plate assembly 4 thereon. The winding mount 2 is mounted around the axial tube 13 and includes a winding 21 wound therearound.
The upper pole plate assembly 3 may comprise a stack of silicon steel plates, and the number of the poles are selected according to the need. Similarly, the lower pole plate assembly 4 may comprise a stack of silicon steel plates, and the number of the poles thereof is the same as that of the upper pole plate assembly 3. The upper pole plate assembly 3 includes a number of annularly spaced pole edges 31, and the lower pole plate assembly 4 also includes a number of annularly spaced pole edges 41, wherein each pole edge 31 has an area not equal to that of the pole edge 41. In order to provide the unequal areas between the pole edges 31 and 41, the pole edges 31 and 41 may have either different heights H1, H2 (Fig. 2) or different widths W1, W2 (Fig. 3).
It is appreciated that, since the pole edges 31 and 41 have different areas, an attractive force between the upper pole plate assembly 3 and the annular magnet 51 is not equal to that between the lower pole plate assembly 4 and the annular magnet 51 to thereby generate a slight torque therebetween, thereby overcoming the sudden torque generated during the change in the polarity during rotation of the motor. Accordingly, the vibrations of the motor during rotation are reduced to allow the rotor to operate in a more stable manner.
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed.

Claims (4)

What is claimed is:
1. A brushless motor, comprising: a base plate including an axial tube mounted thereon! a winding mount mounted around the axial tube and including a winding wound therearound, the winding mount having an upper end and a lower end, an upper pole plate assembly mounted on the upper end of the winding mount and including a plurality of annularly spaced upper pole edges, a lower pole plate assembly mounted on the lower end of the winding mount and including a plurality of annularly spaced lower pole edges, each said lower pole edge having an area different from that of each said upper pole edge, and a rotor including a rotating shaft rotatably received in the axial tube and an annular magnet mounted therein.
2. The brushless motor according to claim 1, wherein said upper pole edge and said lower pole edge have different widths.
3. The brushless motor according to claim 1, wherein said upper pole edge and said lower pole edge have different heights.
4. The brushless motor substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
GB9720643A 1997-09-29 1997-09-29 Brushless motors with reduced vibrations Expired - Fee Related GB2329763B (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB9720643A GB2329763B (en) 1997-09-29 1997-09-29 Brushless motors with reduced vibrations
DE29718710U DE29718710U1 (en) 1997-09-29 1997-10-09 Vibration-reduced brushless electric motor
FR9712894A FR2769766B3 (en) 1997-09-29 1997-10-15 MOTOR WITHOUT REDUCED VIBRATION MANIFOLD

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9720643A GB2329763B (en) 1997-09-29 1997-09-29 Brushless motors with reduced vibrations
DE29718710U DE29718710U1 (en) 1997-09-29 1997-10-09 Vibration-reduced brushless electric motor
FR9712894A FR2769766B3 (en) 1997-09-29 1997-10-15 MOTOR WITHOUT REDUCED VIBRATION MANIFOLD

Publications (3)

Publication Number Publication Date
GB9720643D0 GB9720643D0 (en) 1997-11-26
GB2329763A true GB2329763A (en) 1999-03-31
GB2329763B GB2329763B (en) 2001-06-06

Family

ID=27220024

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9720643A Expired - Fee Related GB2329763B (en) 1997-09-29 1997-09-29 Brushless motors with reduced vibrations

Country Status (3)

Country Link
DE (1) DE29718710U1 (en)
FR (1) FR2769766B3 (en)
GB (1) GB2329763B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2357378A (en) * 1999-09-10 2001-06-20 Sunonwealth Electr Mach Ind Co Brushless DC motor fan driven by an AC power source
GB2358740A (en) * 2000-01-28 2001-08-01 Imp Ltd Modular electric motor
US6909215B2 (en) 2000-01-28 2005-06-21 John Graham Bryant Electric motor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001178087A (en) * 1999-12-03 2001-06-29 Jianzhun Electric Mach Ind Co Ltd Rotor of motor and manufacturing method therefor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5679997A (en) * 1992-08-12 1997-10-21 Seiko Epson Corporation Brushless DC motor and method for driving the same

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5679997A (en) * 1992-08-12 1997-10-21 Seiko Epson Corporation Brushless DC motor and method for driving the same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2357378A (en) * 1999-09-10 2001-06-20 Sunonwealth Electr Mach Ind Co Brushless DC motor fan driven by an AC power source
GB2357378B (en) * 1999-09-10 2005-02-09 Sunonwealth Electr Mach Ind Co Brushless DC motor fan driven by an AC power source
GB2358740A (en) * 2000-01-28 2001-08-01 Imp Ltd Modular electric motor
GB2358740B (en) * 2000-01-28 2005-02-16 Imp Ltd Electric motor
US6909215B2 (en) 2000-01-28 2005-06-21 John Graham Bryant Electric motor

Also Published As

Publication number Publication date
GB9720643D0 (en) 1997-11-26
DE29718710U1 (en) 1997-11-27
FR2769766B3 (en) 1999-09-03
FR2769766A3 (en) 1999-04-16
GB2329763B (en) 2001-06-06

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20090929