U.S. patent number RE32,702 [Application Number 06/626,611] was granted by the patent office on 1988-06-21 for brushless d.c. motor assembly.
This patent grant is currently assigned to Papst-Motoren GmbH & Co KG. Invention is credited to Alfred Hasler, Bernhard Schuh.
United States Patent |
RE32,702 |
Hasler , et al. |
June 21, 1988 |
Brushless D.C. motor assembly
Abstract
An improved motor assembly including a brushless D.C. motor and
an annular member defining a platform for the drive electronics and
speed control circuits of the motor. The member is carried on a
fixed support within the outer envelope of the motor and includes a
thin disk-like body providing a pair of opposed surfaces for
mounting the components of the circuits. The fixed support of the
motor has a flat annular face surrounding the drive shaft of the
motor, and the annular member engages and is secured to the flat
face of the support in surrounding relationship to the shaft. In a
preferred embodiment, the housing of the motor defines part of the
rotor of the motor and is for rotation with the shaft. A flange is
secured to the support near the opposite end of the shaft for
mounting the motor on a fixed support, such as on the base of a
housing forming a part of a disk drive unit. Impeller blades can be
secured to one end of the shaft or to the side of the housing to
supply cooling air to a region adjacent to the motor.
Inventors: |
Hasler; Alfred (Saratoga,
CA), Schuh; Bernhard (Baindt, DE) |
Assignee: |
Papst-Motoren GmbH & Co KG
(St. Georgen, DE)
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Family
ID: |
27090207 |
Appl.
No.: |
06/626,611 |
Filed: |
June 29, 1984 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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957769 |
Nov 3, 1978 |
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Reissue of: |
154542 |
May 29, 1980 |
04337491 |
Jun 29, 1982 |
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Current U.S.
Class: |
360/99.08;
360/137 |
Current CPC
Class: |
G11B
19/2009 (20130101); H02K 11/33 (20160101); G11B
33/121 (20130101); G11B 25/043 (20130101) |
Current International
Class: |
G11B
19/20 (20060101); G11B 19/20 (20060101); G11B
25/04 (20060101); G11B 25/04 (20060101); G11B
33/12 (20060101); G11B 33/12 (20060101); H02K
29/00 (20060101); H02K 29/00 (20060101); H02K
11/04 (20060101); H02K 11/04 (20060101); G11B
025/04 () |
Field of
Search: |
;360/102-103,97-99
;310/68 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1638216 |
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Jul 1971 |
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DE |
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2145478 |
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Mar 1972 |
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DE |
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2136170 |
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Feb 1973 |
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DE |
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2245557 |
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Mar 1973 |
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DE |
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1638380 |
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Jun 1973 |
|
DE |
|
2560207 |
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Dec 1975 |
|
DE |
|
2612464 |
|
Mar 1978 |
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DE |
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Primary Examiner: Wolff; John H.
Attorney, Agent or Firm: Koss, Jr.; Theodore J.
Parent Case Text
This is a continuation of application Ser. No. 957,769, filed Nov.
3, 1978.
Claims
We claim:
1. In a magnetic disk recording assembly of the type having a
casing provided with a pair of adjacent air flow chambers separated
by a wall with one of the chambers having a magnetic disk for
rotation relative to a magnetic read-write head and the other
chamber being isolated from the first chamber and containing first
circuitry means for the head, the improvement comprising a
brushless D.C. motor having an external housing; means coupled with
the motor for mounting it on the casing externally of said one
chamber, said motor having a fixed part and a shaft rotatable
relative to the fixed part, the shaft adapted to extend through
said wall of the casing and to be coupled at one end thereof to the
magnetic disk for rotating the magnetic disk about its central
axis, the motor having second circuitry means for controlling the
excitation of the motor, and an annular support member carried by
the fixed part in surrounding relationship to the shaft of the
motor, said second circuitry means being mounted on the support
member.
2. In a magnetic disk recording assembly as set forth in claim 1,
wherein the external housing of the motor has means secured to the
shaft for mounting the external housing on the shaft for rotation
therewith, the housing having an open end, the fixed part being
near the open end and the .[.circuitry mounting means.].
.Iadd.support member that mounts the second circuitry means
.Iaddend.being exteriorly of the housing.
3. In a magnetic disk recording assembly as set forth in claim
.Iadd.1 or .Iaddend.2, wherein the .[.mounting.]. means
.Iadd.coupled with the motor for mounting it on the casing
.Iaddend.includes a platform in a plane extending transversely to
the shaft.
4. In a magnetic disk recording assembly as set forth in claim 3,
wherein the annular member is secured to the fixed part and
surrounds the shaft.
5. In a magnetic disk recording assembly as set forth in claim 1,
wherein is included a fan mounted on the opposite end of the shaft
for blowing air into the other chamber when the shaft rotates.
6. In a magnetic disk recording assembly as set forth in claim
.[.1.]. .Iadd.3.Iaddend., wherein .[.the motor has an.]. .Iadd.said
.Iaddend.external housing .Iadd.is .Iaddend.secured to the shaft
for rotation therewith.[., and including a fan secured to the
housing for blowing air into the other chamber when the shaft and
housing rotate.]..
7. In a magnetic disk recording assembly as set forth in claim 6,
.Iadd.and including a fan secured to the housing for blowing air
into the other chamber when the shaft and housing rotate,
.Iaddend.wherein said housing has an end face remote from the wall,
the fan being on said end face.
8. An assembly as set forth in claim 6, .Iadd.and including a fan
secured to the housing for blowing air into the other chamber when
the shaft and housing rotate, .Iaddend.wherein said housing has a
cylindrical outer surface, said fan including a number of spaced
blades secured to said cylindrical outer surface. .Iadd.
9. In a magnetic disk recording assembly as set forth in claim 1,
wherein said second circuitry means comprises drive electronics
means for motor commutation. .Iaddend. .Iadd.10. In a magnetic disk
recording assembly as set forth in claim 1, wherein said second
circuitry means comprises drive electronics means for motor
commutation and speed control circuit means for controlling the
speed of the motor. .Iaddend. .Iadd.11. In a magnetic disk
recording assembly as set forth in claim 1, wherein said second
circuitry means comprises means for sensing the position of the
rotor of the motor. .Iaddend. .Iadd.12. In a magnetic disk
transducer assembly of the type having a casing provided with a
pair of adjacent air flow chambers separated by a wall with one of
the chambers having a rotary disk-holding structure for a magnetic
disk for rotation relative to a magnetic transducer head and the
other chamber being isolated from the first chamber, the
improvement comprising a brushless D.C. motor having an external
housing; means coupled with the motor for mounting it on the casing
externally of said one chamber, said motor having a fixed part and
a shaft rotatable relative to the fixed part, the shaft adapted to
extend through said wall of the casing and to be coupled at one end
thereof to the magnetic disk for rotating a magnetic disk about its
central axis, the motor having circuitry means for controlling the
excitation of the motor, and an annular support member carried by
the fixed part in surrounding relationship to the shaft of the
motor, said circuitry means being mounted
on the support member. .Iaddend. .Iadd.13. In a magnetic disk
transducer assembly as set forth in claim 12, wherein the external
housing of the motor has means secured to the shaft for mounting
the external housing on the shaft for rotation therewith, the
housing having an open end, the fixed part being near the open end
and the support member that mounts the circuitry means being
exteriorly of the housing. .Iaddend. .Iadd.14. In a magnetic disk
transducer assembly as set forth in claim 12 or 13, wherein the
means coupled with the motor for mounting it on the casing includes
a platform in a plane extending transversely to the shaft.
.Iaddend. .Iadd.15. In a magnetic disk transducer assembly as set
forth in claim 14, wherein the annular member is secured to the
fixed part and surrounds the shaft. .Iaddend. .Iadd.16. In a
magnetic disk transducer assembly as set forth in claim 12, wherein
is included a fan mounted on the opposite end of the shaft for
blowing air into the other chamber when the shaft rotates.
.Iaddend. .Iadd.17. In a magnetic disk transducer assembly as set
forth in claim 12, wherein said external housing is secured to the
shaft for rotation therewith. .Iaddend. .Iadd.18. In a magnetic
disk transducer assembly as set forth in claim 17, and including a
fan secured to the housing for blowing air into the other chamber
when the shaft and housing rotate, wherein said housing has an end
face remote from the wall, the fan being on said end face.
.Iaddend. .Iadd.19. An assembly as set forth in claim 17, and
including a fan secured to the housing for blowing air into the
other chamber when the shaft and housing rotate, wherein said
housing has a cylindrical outer surface, said fan including a
number of spaced blades secured to said cylindrical outer surface.
.Iaddend. .Iadd.20. In a magnetic disk recording assembly as set
forth in claim 12, wherein said circuitry means comprises drive
electronics means for motor commutation.
.Iaddend. .Iadd.21. In a magnetic disk recording assembly as set
forth in claim 12, wherein said circuitry means comprises drive
electronics means for motor commutation and speed control circuit
means for controlling the speed of the motor. .Iaddend. .Iadd.22.
In a magnetic disk recording assembly as set forth in claim 12,
wherein said circuitry means comprises means for sensing the
position of the rotor of the motor. .Iaddend.
Description
This invention relates to improvements in brushless D.C. motors
and, more particularly, to a motor of this type which is
essentially self-contained except for its connection with an
external source of electrical power.
BACKGROUND OF THE INVENTION
Brushless D.C. motors are typically provided with electrical
circuitry which provides the drive electronics and the speed
control means therefor. The drive electronics provides the
electronic means which replaces the brushes and commutators of
conventional D.C. motors. The speed control means is typically an
optical tachometer which senses the speed of rotation of the drive
shaft of the motor and applies signals to the drive electronics to
control the speed of the shaft. The optical device of the
tachometer also acts as a sensor for sensing the position of the
rotar for communication of the currents to the motor windings.
In the past, the drive electronics and speed control circuits have
been mounted in a "black box" which is separate and apart from the
motor. This "black box" takes up additional space and requires a
cable connecting it with the magnetic means, such as the field
coils, of the motor.
The use of such a "black box" in conventional D.C. motors cannot be
tolerated in certain applications because of space limitations. For
instance, a disk drive unit is being made as small as practical and
must be as compact as possible yet must have all of the features
for driving magnetic disks as are found in larger disk drive units.
Brushless D.C. motors are suitable for this application because of
their reliability, absence of arcing, such as occurs at the brushes
of conventional D.C. motors, and the ease of operation when coupled
to a hub carrying a pair of spaced magnetic disks. Use of a
conventional brushless D.C. motor for this application is not
satisfactory because space would have to be provided for its "black
box". This would in all likelihood be an inconvenience for the user
of the disk drive unit. Because of the foregoing drawbacks, a need
has arisen for an improved brushless D.C. motor, one in which the
"black box" of the type described is eliminated.
SUMMARY OF THE INVENTION
The present invention satisfies the aforesaid need by providing an
improved brushless D.C. motor assembly which includes not only the
motor itself but also a platform within the confines of the motor
envelope for supporting the drive electronics and speed control
circuits of the type described. This assembly, therefore,
completely eliminates the need for the "black box" of the type
described so that the assembly is suitable for a wide variety of
uses, including use as the drive motor for the disks of a disk
drive unit.
The drive motor assembly of this invention includes a drive shaft
surrounded by a support carrying bearings which journal the shaft
for rotation, the support having means for connecting it to an
annular disk-like member provided with a pair of opposed faces on
which the drive electronics and speed control circuits are mounted.
Since the annular member is within the envelope of the drive motor,
the drive motor assembly is essentially self-contained except for
the fact that it has leads for connection to an external source of
electrical power, thereby causing the assembly to be highly compact
without adding to its weight and without distracting from its high
reliability.
The primary object of the invention is to provide an improved
brushless D.C. motor assembly which eliminates the need for a
"black box" for containing the drive electronics and speed control
circuits so that these circuits can form a part of the motor
assembly and be within the envelope of the motor housing to provide
a compact unit suitable for a wide variety of uses, especially use
as the drive motor of a disk drive unit.
Other objects of this invention will become apparent as the
following specification progresses, reference being had to the
accompanying drawing for an illustration of an embodiment of the
invention.
IN THE DRAWING
FIG. 1 is a side elevational view, partly in section, of the
improved brushless D.C. motor assembly of this invention, showing
one way in which it can be mounted, such as in the housing of a
disk drive unit of the type having a pair of magnetic disks mounted
on a rotatable hub;
FIG. 2 is a top plan view of an annular member forming a part of
the drive motor assembly and serving as a platform for the
circuitry, including the drive electronics circuit and speed
control circuit, of the drive motor of the assembly, the annular
member being on a reduced scale with reference to that of FIG.
1;
FIG. 3 is a top plan view of the drive motor assembly coupled with
the disk drive unit of FIG. 1 with the housing cover and hub
removed, parts being broken away to illustrate details of
construction of the drive motor assembly;
FIG. 4 is a cross-sectional view of the drive motor assembly;
and
FIG. 5 is a view similar to FIG. 1 but showing a number of spaced
impeller blades on the outer surface of the motor housing.
The improved brushless D.C. motor assembly of this invention is
broadly denoted by the numeral 10 and includes a conventional
brushless D.C. motor 11 which includes a rotatable drive shaft 12,
an outer, hollow housing 14 surrounding the coils, iron cores and
permanent magnets (hereinafter described) of a motor of this type,
drive electronics circuit 16 for said coils, and speed control
circuit 18 coupled with circuit 16 for controlling the speed of
rotation of shaft 12. All of the foregoing elements of motor 11 are
old and, in combination, define a conventional brushless D.C.
motor. The improvement afforded by the present invention is the use
of an annular member 20 coupled to a fixed part or central support
22 of motor 11 for supporting drive electronics circuit 16 and
speed control circuit 18 so that these circuits form a compact unit
with motor 11. This feature eliminates the need for a "black box"
spaced from the motor for housing these two circuits. Such a "black
box" has been used in the past for conventional motors of this
type.
As shown in FIG. 1, the various components 24 of circuits 16 and 18
are shown in the space 26 between the upper marginal edge 28 of
motor housing 14 and an annular mounting flange 30 rigid to central
support 22 of motor 11. Leads 31 extend away from circuits 16 and
18 and are adapted to be connected to a D.C. voltage source.
Assembly 10 can include a fan 32 having a number of impeller blades
33 rigid to one end 34 of shaft 12, the shaft end 34 projecting
outwardly and downwardly from the bottom of housing 14. Fan 32 is
adapted to direct air laterally and in the direction of arrow 36
(FIG. 1) for cooling purposes hereinafter described. In the
alternative, a number of spaced impeller blades 33a (FIG. 5) could
be mounted on the outer surface of housing 14 for rotation
therewith. These blades operate to move air along paths denoted by
arrows 36a also for cooling purposes to be described.
FIG. 4 shows the way in which motor 10 is assembled. Shaft 12 is
rigidly secured by bushing 38 to the bottom 40 of housing 14, the
latter having an open top 42 so that a central sleeve 44
surrounding the shaft can project upwardly from the housing. Sleeve
44 forms a part of central support 22, the sleeve being
press-fitted in a tubular member 46 with which flange 30 is
integral. A pair of bearings 48 within sleeve 44 rotatably mount
shaft 12 within the sleeve so that the shaft and housing 14 rotate
relative to the sleeve and flange 30 when the flange is mounted in
a fixed position to adjacent structure as hereinafter described. A
pair of spaced retaining rings 50 hold the bearings in place.
Moreover, a Bellview washer assembly 52 held by a retaining ring 54
biases the shaft in an upward direction relative to sleeve 44.
Housing 14 has a number of permanent magnets 56 secured to the
inner surface thereof for rotation therewith. These magnets
surround iron cores 58 provided for a number of coils 60 and 62.
Magnets 56, cores 58 and coils 60 and 62 are conventional elements
for brushless D.C. motors of this type. Housing 14 and magnets 56
form the rotor of motor 11.
Annular support member 20 has an outer diameter essentially the
same as that of housing 14 and flange 30. Thus, member 20 is
retained within the outer envelope of motor 11 to form a compact
unit therewith. Member 20 has a central hole 64 (FIG. 2)
therethrough which is of a size sufficient to permit the member to
be placed over sleeve 44 and against a lower, flat face 66 on
tubular member 46 (FIG. 4). Member 20 is secured to face 66 in any
suitable manner, such as by fasteners or by an adhesive. The axial
length of tubular member 46 is sufficient to allow components 24 to
be accommodated in space 26 without interference with flange
30.
While motor assembly 11 can be used in a number of different
applications, it will be described as being useful with a disk
drive unit 68 of the type having a housing or casing 70 provided
with a base 72 and a removable cover 74. The space 76 within cover
74 and above base 72 is adapted to contain a pair of rotatable
disks 78 and 80 rigidly secured to a hub 82 which is to be
adjustably and removably secured to the upper end of shaft 12.
Base 72 has a space 84 for receiving motor assembly 10 and a top
web 86 to which flange 30 is releasably connected, such as by screw
fasteners .Iadd.30a .Iaddend.or the like. In such a position, shaft
12 extends upwardly through an opening 90 in web 86 so that the
upper end of the shaft projects into space 76 to allow hub 82 to be
secured to shaft 12 for rotation therewith within space 76. If fan
32 is used with assembly 10, it is connected to the lower end of
shaft 32 and operates to blow cooling air in the direction of arrow
36, such as into lateral region 102 which might contain circuit
boards and other electronic circuitry connected with the shiftable
read-write heads 96 (FIG. 1) associated with disks 78 and 80.
In use, motor assembly 30 is coupled to base 72 with flange 30
secured to web 86. The power supplied to the drive electronics and
speed control circuits 16 and 18 causes motor 11 to be energized,
causing shaft 12 and housing 14 to rotate within space 84 relative
to flange 30 and support 22. As motor housing 14 rotates, disks 78
and 80 are rotated relative to heads 94 as member 20 remains
stationary. Impeller blades 33 or 33a are rotated with housing 14
and direct air laterally for the purpose mentioned above.
* * * * *