U.S. patent application number 11/826965 was filed with the patent office on 2007-11-15 for motor and magnetic bearing assembly thereof.
Invention is credited to Lee-Long Chen, Chien-Heiung Huang, Shih-Ming Huang, Wen-Shi Huang.
Application Number | 20070262669 11/826965 |
Document ID | / |
Family ID | 34859695 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070262669 |
Kind Code |
A1 |
Chen; Lee-Long ; et
al. |
November 15, 2007 |
Motor and magnetic bearing assembly thereof
Abstract
A motor includes a stator, a rotor, and a plurality of blades.
The stator includes a stator base with an opening, a first magnetic
structure disposed at a bottom of the opening, a magnetic pole
disposed on the stator base, and a second magnetic structure
disposed at a top of the magnetic pole. The rotor, coupled to the
stator, includes a hub, a shaft, a third magnetic structure
disposed at the hub and encircled one en of the shaft and
corresponded to the first magnetic structure, and a fourth magnetic
structure disposed at the hub without contacting the second
magnetic structure. The blades encircle the rotor. The first and
third magnetic structures attract the second and the fourth
magnetic structures, respectively.
Inventors: |
Chen; Lee-Long; (Taoyuan
Hsien, TW) ; Huang; Chien-Heiung; (Taoyuan Hsien,
TW) ; Huang; Shih-Ming; (Taoyuan Hsien, TW) ;
Huang; Wen-Shi; (Taoyuan Hsien, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
34859695 |
Appl. No.: |
11/826965 |
Filed: |
July 19, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11060759 |
Feb 18, 2005 |
|
|
|
11826965 |
Jul 19, 2007 |
|
|
|
Current U.S.
Class: |
310/90.5 |
Current CPC
Class: |
F16C 17/08 20130101;
F16C 39/063 20130101; F16C 32/041 20130101; H02K 7/09 20130101;
F16C 2360/46 20130101; F16C 2380/26 20130101 |
Class at
Publication: |
310/090.5 |
International
Class: |
H02K 7/09 20060101
H02K007/09 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2004 |
TW |
93104224 |
Claims
1. A magnetic bearing assembly, comprising: a first hub, having a
first opening, a first magnetic structure disposed in the opening,
and a second magnetic structure disposed at a portion of the first
hub encircled the opening; and a second hub, having a main body
with a first protrusion protruding from a side thereof, a third
magnetic structure disposed at the first protrusion and
corresponding to the first magnetic structure, and a fourth
magnetic structure disposed at the main body above or below the
second magnetic structure without contacting the same; wherein
magnetic attraction is generated between the first and the third
magnetic structures, and magnetic attraction is generated between
the second and the fourth magnetic structures, and wherein the
first magnetic structure has a first magnet and a second magnet
disposed at a periphery of the first magnet, the second magnet of
the first magnetic structure and the third magnetic structure
attract each other, and the first magnet of the first magnetic
structure and the third magnetic structure repel each other.
2. The magnetic bearing assembly as claimed in claim 1, wherein the
second hub further comprises a second opening located on the other
side of the main body.
3. The magnetic bearing assembly as claimed in claim 1, further
comprising an intermediate structure, located between the first
magnetic structure and the end of the first protrusion, or between
the end of the first protrusion and a wear-resistant structure.
4. The magnetic bearing assembly as claimed in claim 3, wherein the
intermediate structure has a curved face or has a shape which is
spherical, elliptical, turbinate, tapered with a curved end, or
arrow-shaped with a curved end.
5. The magnetic bearing assembly as claimed in claim 1, further
comprising a second protrusion, protruding from the other side of
the main body, the fourth magnetic structure being disposed at the
other side of the main body below the second magnetic structure
without contacting the same.
6. The magnetic bearing assembly as claimed in claim 1, wherein the
second hub is formed by a plurality of sub hubs.
7. The magnetic bearing assembly as claimed in claim 1, further
comprising a wear-resistant structure, positioned between the first
magnetic structure and the end of the first protrusion, and
contacting the end of the first protrusion at a contact point or a
little contact area.
8. The magnetic bearing assembly as claimed in claim 1, wherein the
first magnetic structure has a first magnet and a second magnet
disposed at a periphery of the first magnet, the second magnet of
the first magnetic structure and the third magnetic structure
attract each other, and the first magnet of the first magnetic
structure and the third magnetic structure repel, wherein the first
magnet and the second magnet of the first magnetic structure are
two opposite poles.
9. The magnetic bearing assembly as claimed in claim 1, further
comprising a magnetic conduction layer formed between the first
magnetic structure and the bottom of the opening, the second
magnetic structure and the periphery of the opening, the third
magnetic structure and the main body, or the fourth magnetic
structure and the main body.
10. The magnetic bearing assembly as claimed in claim 1, wherein
the first magnetic structure is disposed at a bottom of the opening
or at a third protrusion which protrudes from a sidewall of the
opening.
11. The motor as claimed in claim 1, wherein the third magnetic
structure is disposed at the main body and encircles one end of the
first protrusion.
12. A motor, adapted to be used in a fan, comprising: a stator,
having a stator base with an opening, a first magnetic structure
disposed at the opening or at a protrusion protruding from a
sidewall of the opening, and a second magnetic structure disposed
at the stator base encircling the opening; a rotor coupled to the
stator, having a hub, a shaft, a third magnetic structure disposed
at the shaft and corresponding to the first magnetic structure, and
a fourth magnetic structure disposed at the hub without contacting
the second magnetic structure; and an intermediate structure,
located between the first magnetic structure and the end of the
shaft, or between the end of the shaft and a wear-resistant
structure; wherein magnetic force is generated between the first
and the third magnetic structures, and magnetic force is generated
between the second and the fourth magnetic structures.
13. The motor as claimed in claim 12, wherein the material of the
intermediate structure is magnetic conduction metal, magnetic
conduction plastics, or other magnetic conduction materials.
14. The motor as claimed in claim 12, wherein the intermediate
structure has a curved face or has a shape which is spherical,
elliptical, turbinate, tapered with a curved end, or arrow-shaped
with a curved end.
15. The motor as claimed in claim 12, wherein the third magnetic
structure is disposed at the hub and encircles one end of the
shaft.
Description
[0001] This application is a Continuation of co-pending application
Ser. No. 11/060,759, filed on Feb. 18, 2005 and for which priority
is claimed under 35 U.S.C. .sctn. 120, which claims priority of
Application No. 093104224 filed in Taiwan on Feb. 20, 2004 under 35
U.S.C. .sctn. 119, the entire contents of which are hereby
incorporated by reference.
BACKGROUND OF INVENTION
Field of the Invention
[0002] The present invention relates to a motor, a fan, and a
magnetic bearing assembly thereof, and in particular to a motor, a
fan, and a magnetic bearing assembly thereof with characteristics
of less abrasion, low noise level, low costs, and longer
lifetime.
[0003] A conventional motor includes a shaft, a rotor, and a
bearing. The rotor is disposed on the shaft and supported by the
bearing, enabling the rotor to rotate smoothly.
[0004] Conventional bearings include ball bearings, sleeve
bearings, dynamic bearings, and magnetic bearings.
[0005] However, the structure of the ball bearing is weak and
susceptible to impact. When the motor with the ball bearing
operates, the balls are rolling at high speed and producing
excessive noise. The ball bearing requires a higher degree of
accuracy, thus increasing manufacturing costs.
[0006] A sleeve bearing is formed by mixing and sintering bronze
powder, iron powder, nickel powder, lead powder and other metal
powders. Lubricant is applied into the pores of the bearing. When
the motor operates, lubricant exudes from the bearing such that the
rotor rotates in the lubricant. This type of bearing can sustain
higher impact than the ball bearing, and manufacturing costs are
also reduced. In a motor utilizing the sleeve bearing, however, the
lubricant evaporates into gas as the bearing operates over long
periods. As the result, the shaft directly contacts the bearing
such that friction is produced therebetween. Furthermore, nitrides
can possibly form at the ends of the bearing, causing damage and
excessive noise. In addition, dust in the air may be drawn into the
center of the motor during operation, contaminating the lubricant
surrounding the bearing, increasing the noise level and occluding
moving parts. Furthermore, since the gap between the bearing and
the shaft is small, the efficiency in starting the motor is
reduced.
[0007] A dynamic bearing is a variation of the sleeve bearing. This
type of bearing includes an inner wall with two annular arrays of
V-shaped grooves formed therein, preventing lubricant evaporation.
Formation of the grooves on the inner side of the dynamic bearing,
however, requires precise manufacturing. Thus, the manufacturing
cost is higher than other types of bearings. Moreover, the dynamic
effect is not achieved at low speeds, such that performance of the
dynamic bearing is substantially the same as a sleeve bearing.
[0008] To solve the above problems, a magnetic bearing is disclosed
in U.S. Pat. No. 6,414,411. A rotor, a stator, and a balance plate
are combined in such way that attraction is generated between the
rotor and the balance plate. In this structure, however, the
magnetic bearing does not disclose a radial supporting structure,
and consequently, the shaft and the bearing may collide during
operation, reducing product life of the motor and producing
excessive noise.
[0009] Furthermore, other patents such as Japan No. S55-36635 (4),
Japan No. S64-39926, Japan No. H05-146109, Japan No. S58-083552,
U.S. Pat. No. 6,265,798, U.S. Pat. No. 5,507,629, U.S. Pat. No.
5,840,070, U.S. Pat. No. 3,934,950, U.S. Pat. No. 3,663,075, U.S.
Pat. No. 4,340,260, U.S. Pat. No. 5,894,181, U.S. Pat. No.
5,280,208, and U.S. Pat. No. 5,019,738, disclose similar structures
with the same magnetic polarity designed at a shaft of a rotor and
a stator base, thereby the like poles produce repulsive force
therebetween such that repulsive force suspends the shaft in the
stator base without direct contact. The repulsive force, however,
may be diminished if the position of the shaft is offset by
external force or driving force during operation, the imbalance can
cause the shaft to contact or be expelled from the stator base.
[0010] In addition, another U.S. Pat. No. 5,561,335 discloses
additional magnets attached to two ends of the magnet of the rotor,
providing magnetic balance of the shaft, as shown in FIG. 7 in U.S.
Pat. No. 5,561,335. During operation, however, if the magnet is
disposed at an incorrect attractive angle with an incorrect moment
arm of the magnet, the additional magnet may be adversely frozen
due to magnetic attraction, and thus operation is interrupted.
[0011] Thus, collisions between the shaft and the bearing may
easily occur in conventional motors. This produces excessive noise,
shortens product life, and can interrupt normal motor operation.
Hence, it can be seen, the magnetic bearing is still in an
experimental stage, and is not yet ready for mass production.
SUMMARY OF THE INVENTION
[0012] Embodiments of the present invention, therefore, provide a
motor that eliminates the previously described shortcomings.
[0013] Embodiments of the invention additionally provide a motor
and a magnetic bearing assembly thereof with lower manufacturing
cost, lower friction, enhanced performance, longer product life,
and lower noise.
[0014] Embodiments of the present invention further provide a motor
including a stator, a rotor, and a plurality of blades. The stator
includes a stator base with an opening, a first magnetic structure
disposed at a bottom of the opening, a magnetic pole disposed on
the stator base, and a second magnetic structure disposed at a top
of the magnetic pole. The rotor is coupled to the stator and the
rotor includes a hub, a shaft, a third magnetic structure and a
fourth magnetic structure. The third magnetic structure is disposed
at the hub and encircles one end of the shaft and corresponds to
the first magnetic structure. The fourth magnetic structure is
disposed at the hub without contacting the second magnetic
structure.
[0015] The blades encircle the rotor. Magnetic attraction is
generated between the first magnetic structure and the third
magnetic structure. Additionally, magnetic attraction is generated
between the second magnetic structure and the fourth magnetic
structure.
[0016] Embodiments of the present invention also provide a motor
including a mutually attractive rotor and stator. The stator
includes a stator base with an opening, a first magnetic structure
disposed at a bottom of the opening, or a protrusion protruded from
a sidewall of the opening. The rotor is coupled to the stator and
the rotor includes a hub, a shaft, a second magnetic structure, and
a third magnetic structure. The second magnetic structure is
disposed at the hub and encircles one end of the shaft which is
protruded from a side of the hub and corresponds to the first
magnetic structure. The third magnetic structure is disposed at
other end of the shaft protruded from other side of the hub. The
housing surrounds the stator and the rotor, and the housing
includes a fourth magnetic structure disposed at the housing above
and without contacting the third magnetic structure. The blades
encircle the rotor. Magnetic attraction is generated between the
first and the second magnetic structures, and also magnetic
attraction is generated between the third and the fourth magnetic
structures.
[0017] In embodiments of the present invention, the magnetic
structure at the bottom of the opening includes a central magnet
and a surrounding magnet encircling a periphery of the central
magnet such that two magnets are mutually attracted. The magnetic
structure on the rotor corresponding to the magnetic structure at
the bottom of the opening and the surrounding magnet are mutually
attracted, and the shaft and the central magnet attract each
other.
[0018] Furthermore, an end surface of the shaft is flat, curved,
tapered with a curved end, concave, convex, or combinations
thereof. The end portion of the shaft contacts the magnetic
structure at a contact point or via a little contact area.
[0019] In another embodiment, a wear-resistant structure can be
formed on a contact surface between the magnetic structure and the
shaft. The shape of the wear-resistant is flat, curved, tapered
with a curved end, concave, convex, or combinations thereof.
[0020] The magnetic structures are connected by engaging, gluing,
integral formation as a single piece, inserting, clamping, or
combinations thereof. A magnetic conduction layer is formed on the
opposing magnetic surfaces of the magnetic structures. An axial
cross section of the magnetic conduction layer is indented radially
inward or outward, ring-shaped, circular, elliptical, polygonal,
flat, or combinations thereof. In addition, the external periphery
of the magnetic conduction layer includes notches, or the inner
periphery thereof includes notches. The magnetic conduction layer
includes a magnetic conduction metal plate, a non-metal plate, an
iron plate, or combinations thereof.
[0021] At least one blade is formed on a periphery of a hub of the
motor to form a magnetic bearing assembly.
[0022] One embodiment of the present invention provides a magnetic
bearing assembly including an upper (first) and a lower (second)
hub. The upper hub includes a first opening, a first magnetic
structure disposed at a bottom of the opening or a first protrusion
protruded from a sidewall of the opening, and a second magnetic
structure disposed at a periphery of the opening. The lower hub
includes a main body with a second protrusion protruded from a side
of the main body, a third magnetic structure disposed at the main
body and encircling one end of the second protrusion and
corresponding to the first magnetic structure, and a fourth
magnetic structure disposed at the main body above or below without
contacting the second magnetic structure. Magnetic attraction is
generated between the first and the third magnetic structures, and
magnetic attraction is generated between the second and the fourth
magnetic structures.
[0023] Embodiments of the present invention further provide a
magnetic bearing assembly including mutually attractive hubs and a
shaft. The hubs include a hollow portion, a magnetic structure
disposed at an end inner-surface thereof, and another magnetic
structure disposed at the opposing end inner-surface thereof. The
rotor includes a loader, a protrusion located on a top of the
loader and protruding from the hub, a protrusion located at a
bottom of the loader, two magnetic structures corresponding to two
magnetic structures disposed at the hubs. The corresponding
magnetic structures are attracted each other.
[0024] In embodiments of the present invention, the rotor only
contacts the stator at a contact point, and during operation, it is
possible that there is no contact therebetween due to the buoyant
air force. Thus, the noise level of the motor is reduced, and
product life is increased.
[0025] Furthermore, magnetic attraction generated by the shaft and
buoyant air force produced by rotation allow the shaft to rotate
without contact, thus minimizing noise level and increasing product
life thereof.
[0026] The embodiments of the present invention do not require a
conventional bearing, and since conventional elements and
assembling procedures are eliminated, manufacturing and assembly
cost are thus reduced.
[0027] The magnetic bearing assembly can substitute for the
conventional magnetic bearing without modifying the connections
between the fan and the motor, lowering friction therebetween, thus
providing enhanced performance.
[0028] Furthermore, the fan or motor according to embodiments of
the present invention do not have start-up and balance problems.
Thus, the present invention allows mass production of the
motor.
[0029] Further scope of the applicability of the present invention
will become apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The present invention will become more fully understood from
the subsequent detailed description and which are given by way of
illustration only and thus are not limitative of the present
invention and the accompanying drawings, wherein:
[0031] FIG. 1 is a schematic diagram of a motor of a first
embodiment of the present invention;
[0032] FIG. 2 is a schematic diagram of a motor of a second
embodiment of the present invention;
[0033] FIG. 3 is a local enlarged view of a motor of a varied
embodiment of the first embodiment of the present invention;
[0034] FIG. 4 is a schematic diagram of a magnetic bearing assembly
of another varied embodiment of the first embodiment of the present
invention;
[0035] FIG. 5 is a schematic diagram of a magnetic bearing assembly
of a variation according to FIG. 4;
[0036] FIG. 6 is a schematic diagram of a magnetic bearing assembly
of yet another variation according to FIG. 4;
[0037] FIGS. 7A and 7B are schematic diagrams of a magnetic
conduction layer of embodiments of the present invention;
[0038] FIG. 8 is a schematic diagram of a motor of a third
embodiment of the present invention; and
[0039] FIG. 9 is a schematic diagram of a motor of a variation of
the third embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] FIG. 1 is a schematic diagram of a motor 100 of a first
embodiment of the present invention. The motor 100 includes a rotor
142 and a stator 136. When stationary, the rotor 142 contacts the
stator 136 at a contact point. During operation, the rotor 142 and
the stator 136 are connected at a contact point or without
contact.
[0041] The stator 136 includes a stator base 102, a magnetic pole
152, magnetic structures 134 and 138. The stator base 102 includes
an opening 156 at a center thereof. The stator base 102 is
protruded or tube-shaped for loading the rotor 142. The stator base
102 includes plastics, non-magnetic conduction rigid material,
metal, or alloy.
[0042] The magnetic pole 152 of the stator 136 encircles a
periphery of the stator base 102 and is fixed thereon. The magnetic
pole 152 includes silicon steel 104 and a solenoid 120 for
actuating and driving the rotor 142. The magnetic pole 152 can be
an axial solenoid (as shown in FIG. 1), or a radial solenoid. The
silicon steel 104 can be substituted by other types of magnetic
conduction rigid materials. The solenoid 120 includes metal, alloy
or conductive materials.
[0043] Additionally, insulated structures 106a and 106b can be
formed between the silicon steel 104 and the solenoid 120,
preventing electrical connection therebetween.
[0044] The magnetic structure 134 includes a wear-resistant
structure 114, and magnets 110 and 112. Note that the magnets 110
and 112 have different magnetism, and the magnet 112 encircles a
periphery of the magnet 110. The magnetic structure 134 is
connected at the bottom of the opening 156 by engaging, gluing,
integral formation as a single piece, inserting, clamping, or
combinations thereof. The other magnetic structure 138 includes a
magnet 118. The magnetic structure 138 is connected at the
periphery of the opening 156 of the stator base 102 or the top of
the magnetic pole 152 by engaging, gluing, integral formation as a
single piece, inserting, clamping, or combinations thereof. The
magnets 110, 112, and 118 are cylindrical, circular, polygonal,
flat, closed, or block-shaped. The magnets 110, 112, and 118
include magnetic materials or magnetized magnetic conduction
material. The wear-resistant structure 114 is positioned between
the magnetic structure 134 and the shaft 144. The wear-resistant
structure 114 includes durable material with a surface facing the
rotor 142. The shape of the surface is flat, spherical, curved,
elliptical, concave or convex, tapered with a curved end, or
combinations thereof.
[0045] Furthermore, to uniformize the magnetism of the magnets 110,
112, and 118 and increase magnetic effect thereof, magnetic
conduction layers 108 and 116 can be formed on opposing magnetic
faces of the magnets 110, 112, and 118. Furthermore, the magnets
110, 112, and 118 and the magnetic conduction layers 108 and 116
can be connected by gluing, mounting and inserting, engaging, or
clamping.
[0046] The method of connecting the magnetic structure 134 or 138
by clamping is described in the following. The magnets 110, 112, or
118 are fixed on the magnetic conduction layer 108 or 116. A
periphery of the magnetic conduction layer 108 or 116 is an axially
bent sloped side, and the maximum or minimum internal radius of the
sloped side is slightly greater than the internal radius of the
opening 156. The magnetic conduction layer 108 or 116 is then
pressed down to the bottom of the opening 156. An edge of the
magnetic conduction layer 108 or 116 concurrently generates an
elastic recovery force, thereby fixing the edge to the bottom of
the opening 156. The bottom of the opening 156 additionally
includes an engaging structure, or a corresponding engaging
structure is formed between the opening 156 and the magnetic
conduction layers 108 and 116. The magnetic conduction layer 108,
116 is optional and does not have to be sloped. The maximum or
minimum radius of the magnetic conduction layers 108 and 116,
respectively are substantially equal to the internal radius of the
opening 156.
[0047] Moreover, an axial cross section of the magnetic conduction
layers 108 and 116 can be indented radially inward or outward,
ring-shaped, circular, elliptical, polygonal, flat, or combinations
thereof. As shown in FIG. 7A, the cross section of the magnetic
conduction layer 700 has an outer periphery with notches 702. In
FIG. 7B, another cross section of the magnetic conduction layer 704
has an inner periphery with notches 706. The magnetic conduction
layer 108, 116 includes a magnetic conduction metal plate, a
non-metal plate, an iron plate, or combinations thereof.
[0048] Additionally, as shown in FIG. 1, a driving circuit 122 can
be formed on the stator 136 to adjust magnetism of the magnetic
pole 152. The driving circuit 122 can also be directly disposed on
the stator base 102 or disposed outside the motor 100 and connected
externally.
[0049] A side of the stator 136 is covered by the rotor 142, and
the rotor 142 is coupled to the stator 136. The rotor 142 includes
a hub 128, magnetic structures 140, 150, a shaft 144, and a rotary
magnet 132. The hub 128 is cylindrical or protruded, including
plastics, metal, or other rigid material.
[0050] The shaft 144 extends axially and protrudes from the hub
128, acting as a rotational shaft for the rotor 142. The shaft 144
extends into the opening 156 without contacting a sidewall of the
opening 156. The shaft 144 includes magnetic conduction materials
such as magnetic conduction metals or magnetic conduction plastics.
The shaft 144 may directly contact the wear-resistant structure
114, or via intermediate structures such as balls. An end surface
of the shaft 144 can be flat, curved, tapered with a curved end,
concave, convex, or combinations thereof. The end portion of the
shaft 144 contacts the wear-resistant structure 114 at a contact
point or via a little contact area.
[0051] A rotary magnet 132 encircles the magnetic pole 152. The
rotary magnet 132 includes at least one magnet, including multiple
poles, each having a different polarity from an adjacent magnet
thereof. The position of the rotary magnet 132 and the number of
poles thereof correspond to the position of the magnetic pole 152
and the number of poles thereof. The rotary magnet 132 includes
permanent magnets, permanent magnetic tape, rubber magnets, rubber
magnetic tape, or other magnetic structures.
[0052] Another magnetic conduction layer 130 may be disposed
between the hub 128 and the rotary magnet 132 to concentrate
magnetism of the rotary magnet 132, thereby preventing magnetic
force thereof from spreading outward. The magnetic conduction layer
130 also includes a magnetic conduction metal plate, a non-metal
plate, an iron plate, or combinations thereof. Furthermore, if the
hub 128 is magnetically magnetic conduction, the magnetic
conduction layer 130 can be omitted.
[0053] The magnetic structures 140, 150 are disposed above the hub
128, respectively attracting the magnetic structures 138, 134. The
positions and the magnetism of the magnetic structures 140, 150
correspond to those of the magnetic structures 138, 134. The
magnetic structure 140 includes a magnet 126, attracting the other
magnet 118. That is, the magnets 126 and 118 have opposite
polarities. Furthermore, the magnetic structure 140 can be
connected to a magnetic layer 124 on the magnet 126.
[0054] Additionally, the magnetic structure 150 includes a magnet
146 and a magnetic conduction layer 148. The magnets 146 and 112
are mutually attracted with different polarities. Due to
permeability of the magnetic conduction layer 148, magnetic
attraction between the shaft 144 and the magnet 110 are enhanced.
The magnetic structure 150 can be disposed at a periphery of the
end of the shaft 144 or encircled one end of the shaft 144. The
cross section of the magnets 126, 146 can be circular or other
closed-shaped. The material and connection between the magnetic
layers 124, 128 are identical to the above embodiments, thus they
are omitted here.
[0055] Moreover, a periphery of the rotor 142 is encircled with a
plurality of blades 154 such that during rotation, airflow is
produced by the motor 100. The blades 154 can be centrifugal, flat,
or axial.
[0056] FIG. 1 shows an example of a motor 100, explaining how to
balance the rotor 142 therein. During rotation, if the rotor 142 or
the stator 136 is offset radially due to any radial force, since
the magnetic structures 134, 150 located at the bottom of the shaft
144 includes the magnets 112 and 146 with mutually attractive force
therebetween and the magnets 110 and 146 with repulsive force
therebetween (note that the acting directions of the attractive and
repulsive forces are in opposite directions and varying with the
radial force) and because of the attractive force between the
magnetic structures 138 and 140 located at the top of the rotor 142
or a portion of the stator base encircled the opening 156, the
shaft 144 is promptly returned to its original position.
[0057] Moreover, when the rotor 142 receives a force in an inclined
direction, since the attractive force between the magnetic
structures 138 and 140 toward the center thereof helps guide the
rotor 142 to a correct position, the external force is
counterbalanced such that the shaft 144 of the rotor 142 returns to
the central position surrounded by the magnetic structures 138 and
140. Alternatively, when the rotor 142 receives a force in an axial
direction, the axial force is counterbalanced by the axial
attractive force between the magnetic structures 138 and 140,
between the magnets 112 and 146, and between the shaft 144 and the
magnet 110, and an axial supporting force produced by the
wear-resistant structure 114 to the shaft 144, thereby maintaining
the shaft 144 at the center of the predetermined position.
[0058] FIG. 2 is a schematic diagram of a motor 200 of a second
embodiment of the present invention, from which elements common to
the first embodiment are omitted. The difference is that the shaft
144 includes a protrusion 202 protruding from an opposite side of
the hub 128. Two magnetic structures 204 and 218 are disposed on
the protrusion 202 (or the external side of the hub 128) and the
corresponding hub 126, respectively. The two magnetic structures
204 and 218 are formed correspondingly and attracting each other.
That is, the magnetic structures 204 and 218 have opposite
polarity. The magnetic structures 204 at other end of the shaft 144
protruded from other side of the hub 128. The magnetic structure
218 is disposed at the housing 216 above and not touched the
magnetic structures 204.
[0059] The housing 216 contains the stator 136 and the rotor 142
and may include sub housings 212 and 214 or be integrally formed as
a single piece. The housing 216 may also be formed by a plurality
of sub housings. Furthermore, the housing 216 includes at least one
vent for air to flow through.
[0060] The magnetic structure 204 is disposed on an external side
of the hub 128. The magnetic structure 204 includes magnetic
materials or magnetized magnetic conduction materials. The shape of
the magnetic structure 204 can be circular or other closed-shape.
The magnetic structure 204 may include a magnetic conduction layer
to uniformly magnetize the magnetic structure 204. Moreover, the
magnetic structure 204 and the hub 128 or the protrusion 202 can be
connected by engaging, gluing, integral formation as a single
piece, inserting, clamping, or combinations thereof.
[0061] Furthermore, the magnetic structure 218 includes a
wear-resistant structure 210, and magnets 206 and 208. The polarity
of the magnet 206 is different from that of the magnet 208 and the
magnetic structure 204. The magnet 206 encircles the magnet 208.
The magnetic structure 218 is correspondingly fixed to the shaft
144 by engaging, gluing, integral formation as a single piece,
inserting, clamping, or combinations thereof. The magnets 206 and
208 can be cylindrical, ring-shaped, polygonal, polyhedral, flat,
closed-shaped, or block-shaped. The magnets 206 and 208 may include
magnetic material or magnetized magnetic conduction materials. The
wear-resistant structure 210 includes durable materials. The
wear-resistant structure 210 includes a side facing a side of the
rotor 142, the side being flat, curved, tapered with curved end,
concave or convex.
[0062] In this embodiment, the wear-resistant structure is disposed
on the contact surface of the two ends of the shaft, which is
magnetized. Thus, one end is in direct contact, and the other end
is in contact during rotation, thereby maintaining axial and
preventing the rotor from axial vibration or offset.
[0063] Additionally, the corresponding magnetic structures 138, 140
or the other set of magnetic structures 204 and 206 are optional
and can be omitted, depending on requirements.
[0064] FIG. 3 is a local enlarged view of a motor of a variation of
the first embodiment. As shown in FIGS. 1 and 3, the shaft 144 does
not contact the wear-resistant structure 114 of the magnetic
structure 134. An intermediate structure 302 is formed between the
magnetic structures 134 and 150 and contacts the wear-resistant
structure 114 at a contact point or via a little contact area.
During operation, the intermediate structure 302 rotates with the
rotor 142. The intermediate structure 302 includes magnetic
conduction metal, magnetic conduction plastics, or other magnetic
conduction materials. The intermediate structure 302 can be
spherical, elliptical, turbinate, tapered with a curved end,
arrow-shaped with a curved end, and combinations thereof. Moreover,
the intermediate structure 302 includes a curved face on one side
or both sides thereof. A contact surface between the intermediate
structure 302 and the wear-resistant structure 114 can be curved,
tapered with curved end, concave or convex, in which the curve can
be a radius of curvature of a circle. The intermediate structure
302 and the magnetic structure 134 are connected by clamping,
engaging, gluing, welding, or inserting.
[0065] Furthermore, the intermediate structure 302 can be fixed on
a magnetic structure 150, the shaft 144, the hub 128, or
combinations thereof. If the hub 128 is magnetic conduction, the
shaft 144 cannot be formed.
[0066] FIG. 8 is a local enlarged view of a motor 800 of a third
embodiment of the present invention, from which elements common to
the first embodiment are omitted. The difference is that a
protrusion 804 protrudes from a sidewall of an opening 812 of the
stator base 802, and a magnetic structure 806 is formed on an under
portion of the protrusion 804, or a magnetic structure 816 is
formed on an upper portion of the protrusion 804, as shown in FIG.
9. Another magnetic structure 808 or 814 disposed on the shaft 144
is located corresponding to the magnetic structure 806, or 816. The
magnetic structures 806 and 808, or 814 and 816 attract each other.
Moreover, a wear-resistant structure 810 is formed on a bottom of
the opening 812 to contact the shaft 144 at a contact point or via
a little contact area, or without any direct contact therebetween.
The magnetic structures 806, 808, 814 and 816 are identical to the
above embodiments, thus further explanation is omitted. The
position of magnetic structure 806 and 814 are higher than that of
the magnetic structure 808 and 816.
[0067] In a varied embodiment, the shaft 144 can be omitted and
replaced by the intermediate structure, acting as a rotational
shaft. This may also be implemented in the second embodiment such
that the rotor and a central portion of the intermediate structure
are connected, and the intermediate structure replaces the
shaft.
[0068] FIG. 4 is a schematic diagram of a magnetic bearing assembly
400 of a variation of an embodiment of the present invention, from
which elements common to the first embodiment are omitted.
[0069] The magnetic bearing assembly 400 includes hubs 402, 404 and
a shaft 406. The hub 402 includes magnetic structures 138 and 134.
The hub 404 and the shaft 405 include magnetic structures 140 and
150 corresponding to the magnetic structures 138 and 134,
respectively. Specifically, the magnetic structure 134 is disposed
at a bottom of the opening 408. The magnetic structure 138 is
disposed on a periphery of the opening 408. The position and the
poles of the magnetic structure 150 correspond to those of the
magnetic structure 134 on the end of the shaft 406. The position
and the poles of the magnetic structure 140 correspond to those of
the magnetic structure 138 on the hub 404. The shaft 406 protrudes
from a side of the hub 404 or protrudes from both sides
thereof.
[0070] The shaft 406 and the hub 404 are integrally formed as a
single piece or can be connected by inserting, engaging, or gluing.
The shaft 406 includes magnetic conduction metal, magnetic
conduction plastics, or other magnetic conduction materials. The
shaft 406 may directly contact the wear-resistant structure 114, or
contact the wear-resistant structure 114 via intermediate
structures such as ball bearings. An end surface of the shaft 406
is flat, curved, tapered with curved end, concave or convex. The
shaft 406 contacts the wear-resistant structure 114 at a contact
point or via a little contact area. The hubs 404 and 402 include
plastics, magnetic conduction metal, magnetic conduction plastics,
or other magnetic conduction materials.
[0071] The magnetic bearing 400 can be inserted in a stator base of
a fan assembly or motor via the hub 402. The other hub 404 connects
to a rotor of a fan assembly or motor. In this case, the rotor does
not require a shaft. Thus, the embodiments of the present invention
provide lower friction, enhanced performance, longer product life,
and lower noise.
[0072] The magnetic bearing assembly can be modified as shown in
FIG. 5. The difference between the magnetic bearing assemblies 400
and 500 is that the magnetic bearing assembly 500 includes the hub
502 with an opening 504 and a protrusion protruded from a side of
the main body of the hub 502. The entrance of the opening 504 is
located on other side of the main body of the hub 502 away from the
magnetic structure 134. The fan has a shaft that can be directly
inserted through the opening 504 such that the rotor and the hub
502 are connected.
[0073] FIG. 6 is a schematic diagram of a magnetic bearing assembly
600 of another embodiment of the present invention. The difference
between the magnetic bearing assemblies 400 and 600 is that the
magnetic bearing assembly 600 is an independent closed type
bearing. The magnetic bearing assembly 600 includes a hub 614 and a
rotor(shaft) 608. The hub 614 includes a hollow portion 618 and the
shaft 608 is disposed in the hollow portion 618, contained in the
hub 614 and contacting at a contact point. The hub 614 can be an
integral formed as a single piece or include sub hubs 610 and 612
or a plurality of hubs. Magnetic structures 140 and 134 are
disposed on inner-surfaces of an upper and lower ends of the hub
614, respectively. The magnetic structure 140 encircles an opening
616.
[0074] The rotor 608 includes a loader (main body) 602, a
protrusion 604 located on a top of the loader 602, and a protrusion
606 located at a bottom of the loader 602 as a rotational pivot
point. Another set of magnetic structures 138 and 150 with opposite
polarity are disposed on a portion of the loader 602 in vicinity of
the magnetic structures 140 and 134. Thus, attractive force between
the magnetic structures 140 and 138 and between the magnetic
structures 134 and 150 ensures the rotor 608 magnetically suspended
in the hub 614.
[0075] Furthermore, the hubs 402 and 404, hubs 502 and 402, the
rotor 608 and the hub 614 are connected via a contact point or a
little contact area, or without any contact therebetween.
[0076] Additionally, the present invention is not limited to the
disclosed embodiments. Variations may be applied to embodiments of
the bearing structure.
[0077] In practice, the protrusion is fixed on the rotor of the fan
or motor, and the hub is fixed on the stator base. Thus,
embodiments of the present invention provide lower friction,
enhanced performance, longer product life, and lower noise.
[0078] The described embodiments disclose that a solenoid on the
magnetic pole of the stator is a radial solenoid. An axial solenoid
can be one of the selections of the solenoid. Moreover, the motor
is applicable in an axial flow fan motor. Embodiments of the
present invention may be also applied in a frameless motor, a
centrifugal fan motor, a motor with a radial solenoid, a motor with
an axial solenoid, a motor with an outer rotor, or a motor with an
inner rotor.
[0079] The previously described embodiments may be combined or
partially combined and varied.
[0080] In a motor, due to the buoyant force during operation and
magnetic attraction in the shaft, the shaft contacts the stator at
a contact point or without any contact. Thus, the noise of the
motor is greatly reduced, thereby increasing product life.
[0081] Hence, embodiments of the present invention eliminate the
conventional bearing motor, replacing it with an enhanced motor
such that the performance of the motor is optimized, noise is
minimized, and manufacturing costs are reduced.
[0082] While the present invention has been described by way of
example and in terms of the preferred embodiments, it is to be
understood that the present invention is not limited to the
disclosed embodiments. On the contrary, it is intended to hub
various modifications and similar arrangements as would be apparent
to those skilled in the art. Therefore, the scope of the appended
claims should be accorded the broadest interpretation so as to
encompass all such modifications and similar arrangements.
* * * * *