U.S. patent application number 14/186798 was filed with the patent office on 2014-10-30 for high acceleration rotary actuator.
The applicant listed for this patent is GERALD K. LANGRECK. Invention is credited to GERALD K. LANGRECK.
Application Number | 20140319949 14/186798 |
Document ID | / |
Family ID | 44655614 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140319949 |
Kind Code |
A1 |
LANGRECK; GERALD K. |
October 30, 2014 |
HIGH ACCELERATION ROTARY ACTUATOR
Abstract
A high acceleration rotary actuator motor assembly is provided
comprising a plurality of phase motor elements provided in tandem
on a shaft, each phase element including a rotor carrying magnets
which alternate exposed poles, the rotor being connected to the
shaft and surrounded by a stator formed of a plurality of
interconnected segmented stator elements having a contiguous
winding to form four magnetic poles, the stator being in electrical
communication with a phase electric drive unit, wherein each of the
poles exert a magnetic force upon the magnets carried by the rotor
when the poles are electrically charged by the phase electric drive
unit. The rotors and magnets of each phase motor element are offset
about the shaft from one another. In addition, the phase motor
elements are electrically isolated from one another.
Inventors: |
LANGRECK; GERALD K.;
(Phillips, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LANGRECK; GERALD K. |
Phillips |
WI |
US |
|
|
Family ID: |
44655614 |
Appl. No.: |
14/186798 |
Filed: |
February 21, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13913809 |
Jun 10, 2013 |
8674649 |
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14186798 |
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13071932 |
Mar 25, 2011 |
8482243 |
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13913809 |
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61340948 |
Mar 25, 2010 |
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Current U.S.
Class: |
310/112 |
Current CPC
Class: |
H02K 2213/06 20130101;
H02K 1/2706 20130101; H02P 25/02 20130101; H02K 1/148 20130101;
H02K 11/30 20160101; H02K 16/00 20130101 |
Class at
Publication: |
310/112 |
International
Class: |
H02K 16/00 20060101
H02K016/00 |
Claims
1. A high acceleration rotary actuator motor assembly comprising: a
first phase motor element provided on a shaft, the first phase
element including a first rotor carrying a plurality of magnets
which alternate exposed poles, the first rotor being connected to
the shaft and surrounded by a first stator formed of a plurality of
interconnected segmented stator elements having a contiguous
winding to form a plurality of magnetic poles; a second phase motor
element provided on the shaft a first distance from the first phase
motor element, the second phase motor element including a second
rotor carrying a plurality of magnets which alternate exposed
poles, the second rotor being connected to the shaft and surrounded
by a second stator formed of a plurality of interconnected
segmented stator elements having a contiguous winding to form a
plurality of magnetic poles; a third phase motor element provided
on the shaft a second distance from the second phase motor element,
the third phase motor element including a third rotor carrying a
plurality of magnets which alternate exposed poles, the third rotor
being connected to the shaft and surrounded by a third stator
formed of a plurality of interconnected segmented stator elements
having a contiguous winding to form a plurality of magnetic poles;
the second rotor and magnets being offset about the shaft from the
first rotor and magnets by thirty degrees of rotation; the third
rotor and magnets being offset about the shaft from the first rotor
and magnets by sixty degrees of rotation; and the first, second,
and third phase elements being electrically isolated from one
another.
2. The high acceleration rotary actuator motor assembly of claim 1,
wherein the magnets of the first, second and third rotors are
permanent magnets.
3. The high acceleration rotary actuator motor assembly of claim 2,
wherein the permanent magnets of the first, second and third rotors
each have a uniform radius around the shaft.
4. The high acceleration rotary actuator motor assembly of claim 1,
wherein the cross-section of the stator of the first, second and
third phase elements taken in a plane orthogonal to the axis of the
shaft is square in shape.
5. The high acceleration rotary actuator motor assembly of claim 1
wherein the first, second and third phase elements each produce a
square waveform torque constant.
6. The high acceleration rotary actuator motor assembly of claim 1,
wherein the first phase element receives a first phase of a
three-phase electric current, the second phase element receives a
second phase of a three-phase electric current, and the third phase
element receives a third phase of a three-phase electric
current.
7. The high acceleration rotary actuator motor assembly of claim 1,
wherein each of the segmented stator elements of the first, second
and third phase motor elements includes a longitudinal member and a
perpendicular member connected as a unitary element, the
longitudinal member having parallel sides separated by first and
second ends, the perpendicular member being orthogonal to and
bisecting the longitudinal member, the perpendicular member having
an arcuate end opposite the longitudinal member, the first end
defines a receiving aperture and the second end includes an
attachment post, wherein the receiving aperture is adapted to
receive the receiving post of a second segmented stator element and
the attachment post is adapted to be received by the receiving
aperture of a third segmented stator element.
8. The high acceleration rotary actuator motor assembly of claim 1,
wherein the first stator is in electrical communication with a
first phase of an electric drive unit, the second stator is in
electrical communication with a second phase of the electric drive
unit, and the third stator is in electrical communication with a
third phase of the electric drive unit.
9. The high acceleration rotary actuator motor assembly of claim 1,
wherein the poles of the first stator exert a magnetic force upon
the magnets carried by the first rotor when the poles are
electrically charged by an electric drive unit, the poles of the
second stator exert a magnetic force upon the magnets carried by
the second rotor when the poles are electrically charged by the
electric drive unit, and the poles of the third stator exert a
magnetic force upon the magnets carried by the third rotor when the
poles are electrically charged by the electric drive unit.
10. A high acceleration rotary actuator motor assembly comprising:
a shaft carrying a first phase motor element spaced a first
distance from a second phase motor element, a third phase motor
element spaced a second distance from the second phase motor
element, and a fourth phase motor element spaced a third distance
from the third phase motor element; a four pole winding provided in
each stator of each phase motor element; a first rotor connected to
the shaft in the first phase motor element; a second rotor
connected to the shaft in the second phase motor element, the
second rotor is provided on the shaft .pi./8 radians offset from
the first rotor; a third rotor connected to the shaft in the third
phase motor element, the third rotor is provided on the shaft
.pi./4 radians offset from the first rotor; and a fourth rotor
connected to the shaft in the fourth phase motor element, the
fourth rotor is provided on the shaft 3.pi./8 radians offset from
the first rotor.
11. The high acceleration rotary actuator motor assembly of claim
10, wherein each motor element includes a square stator formed of
four interconnecting segmented stator elements, each segmented
stator element including a longitudinal member and a perpendicular
member connected as a unitary element, the longitudinal member
having parallel sides spaced apart by first and second ends, the
perpendicular member being orthogonal to the longitudinal member
and having an arcuate end opposite the longitudinal member, the
first end defines a receiving aperture and the second end includes
an attachment post, wherein the receiving aperture is adapted to
receive the receiving post of a second segmented stator element and
the attachment post is adapted to be received by the receiving
aperture of a third segmented stator element
12. The high acceleration rotary actuator motor assembly of claim
10, wherein the stators of the first, second, third and fourth
first phase motor elements have a square cross-sectional profile
taken perpendicular to the axis of rotation of the shaft.
13. The high acceleration rotary actuator motor assembly of claim
10, further comprising: a first electric drive unit in electric
communication with the first phase motor element; a second electric
drive unit in electric communication with the second phase motor
element; a third electric drive unit in electric communication with
the third phase motor element; and a fourth electric drive unit in
electric communication with the fourth phase motor element, wherein
the first, second, third and fourth phase motor elements are
electrically isolated from one another.
14. The high acceleration rotary actuator motor assembly of claim
10, wherein the first, second, third and fourth rotors each include
a plurality of magnets.
15. The high acceleration rotary actuator motor assembly of claim
14, wherein the magnets of the first, second, third and fourth
rotors are permanent magnets.
16. The high acceleration rotary actuator motor assembly of claim
15, wherein the permanent magnets of the first, second, third and
fourth rotors have a uniform radius around the shaft.
17. The high acceleration rotary actuator motor assembly of claim
15, wherein the first, second, third and fourth rotors each have
four permanent magnets alternating in exposed pole around the
shaft.
18. The high acceleration rotary actuator motor assembly of claim
10, wherein the first phase element receives a first phase of a
four-phase electric current, the second phase element receives a
second phase of the four-phase electric current, the third phase
element receives a third phase of the four-phase electric current,
and the fourth phase element receives a fourth phase of the
four-phase electric current.
19. A high acceleration rotary actuator motor assembly comprising:
a shaft carrying a first phase motor element, a second phase motor
element, and a third phase motor element provided in tandem on the
shaft; a four pole winding provided in each stator of each phase
motor element; a first rotor connected to the shaft in the first
phase motor element, the first rotor carrying four permanent
magnets of a uniform radius and alternating in exposed pole around
the shaft; a second rotor connected to the shaft in the second
phase motor element, the second rotor carrying four permanent
magnets of a uniform radius and alternating in exposed pole around
the shaft, the permanent magnets of the second rotor being provided
on the shaft .pi./6 radians offset from the magnets of the first
rotor; and a third rotor connected to the shaft in the third phase
motor element, the third rotor carrying four permanent magnets of a
uniform radius and alternating in exposed pole around the shaft,
the permanent magnets of the third rotor being provided on the
shaft .pi./3 radians offset from the magnets of the first
rotor.
20. The high acceleration rotary actuator motor assembly of claim
19, wherein each motor element includes a square stator formed of
four interconnecting segmented stator elements, each segmented
stator element including a longitudinal member and a perpendicular
member connected as a unitary element, the longitudinal member
having parallel sides spaced apart by first and second ends, the
perpendicular member being orthogonal to the longitudinal member
and having an arcuate end opposite the longitudinal member, the
first end defines a receiving aperture and the second end includes
an attachment post, wherein the receiving aperture is adapted to
receive the receiving post of a second segmented stator element and
the attachment post is adapted to be received by the receiving
aperture of a third segmented stator element.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority as a continuation
application of U.S. patent application Ser. No. 13/913,809 filed
Jun. 10, 2013, entitled HIGH ACCELERATION ROTARY ACTUATOR, which
claims priority from U.S. patent application Ser. No. 13/071,932,
filed Mar. 25, 2011, now U.S. Pat. No. 8,482,243, entitled HIGH
ACCELERATION ROTARY ACTUATOR, which claims priority from U.S.
Provisional Application Ser. No. 61/340,948, filed Mar. 25, 2010,
entitled HIGH ACCELERATION ROTARY ACTUATOR, the contents of each of
which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a servo motor system. The
present invention more specifically relates to a multi-phase tandem
servo motor assembly for generating high torque at a reduced
inertia.
BACKGROUND
[0003] Servo motors are generally known in the art. A servo motor
is an electromechanical device in which an electrical input
determines a mechanical output, for example the rotational velocity
and torque of a corresponding motor shaft. A servo motor generally
includes a rotor surrounded by a nonmoving stator. Winding, or
coils of wire, are positioned on the stator. Electrical currents
are provided to the winding, producing a rotating magnetic field.
The rotating magnetic field interacts with the rotor, causing the
rotor to turn. The electrical current is generally provided by a
drive. The drive can control the amount of electrical current
transmitted to the motor, correspondingly controlling the rotation
of the motor shaft. Such drives may be referred to as
variable-speed or variable-frequency drives.
[0004] It is desired for some end uses of a servo motor to have a
high torque to low inertia ratio. A servo motor having a high
torque to low inertia ratio provides a fast rate of acceleration of
the motor rotor. However, servo motors as described above have
limitations on the torque to inertia ratio, especially in
applications requiring a larger sized motor. This is due to the
larger, higher weight motor and components necessary to rotate a
rotor at higher speeds or revolutions per minute (RPM).
[0005] In addition, it is desired for some end uses of a servo
motor to operate with a higher power density in a smaller overall
motor package. A higher power density provides for an increase in
efficiency of the servo motor. However, servo motors as described
above have limitations in increasing power density and efficiency.
One reason includes an increase in winding resistance from end turn
waste, effectively reducing stator slot fill. End turns of
traditionally wound motors do not provide power or torque, but
instead generate unnecessary heat, leading to a reduction of motor
efficiency. End turns of the servo motors described above are also
susceptible to heat damage, voltage damage, and insulation
breakdown due to the buildup of heat at the end turns. The end
turns are generally surrounded by air and don't include an adequate
thermal path for heat to escape. This can lead to damage to the
winding, including a short which can render the servo motor
inoperable.
[0006] Accordingly, an improved servo motor assembly having an
improved electronic current driving system is provided.
SUMMARY OF THE INVENTION
[0007] A high acceleration rotary actuator motor assembly is
provided which comprises a first phase motor element provided on a
shaft, the first phase element including a first rotor carrying
four magnets which alternate exposed poles, the first rotor being
connected to the shaft and surrounded by a first stator formed of a
plurality of interconnected segmented stator elements having a
contiguous winding to form four magnetic poles, the first stator
being in electrical communication with a first phase electric drive
unit, wherein each of the poles exert a magnetic force upon the
four magnets carried by the first rotor when the poles are
electrically charged by the first phase electric drive unit. A
second phase motor element is provided on the shaft a first
distance from the first phase motor element, the second phase motor
element including a second rotor carrying four magnets which
alternate exposed poles, the second rotor being connected to the
shaft and surrounded by a second stator formed of a plurality of
interconnected segmented stator elements having a contiguous
winding to form four magnetic poles, the second stator being in
electrical communication with a second phase electric drive unit,
wherein each of the poles exert a magnetic force upon the four
magnets carried by the second rotor when the poles are electrically
charged by the second phase electric drive unit. A third phase
motor element is provided on the shaft a second distance from the
second phase motor element, the third phase motor element including
a third rotor carrying four magnets which alternate exposed poles,
the third rotor being connected to the shaft and surrounded by a
third stator formed of a plurality of interconnected segmented
stator elements having a contiguous winding to form four magnetic
poles, the third stator being in electrical communication with a
third phase electric drive unit, wherein each of the poles exert a
magnetic force upon the four magnets carried by the third rotor
when the poles are electrically charged by the third phase electric
drive unit. The second rotor and magnets are offset about the shaft
from the first rotor and magnets by thirty degrees of rotation,
while the third rotor and magnets being offset about the shaft from
the first rotor and magnets by sixty degrees of rotation. In
addition, the first, second and third phase elements are
electrically isolated from one another.
[0008] In another embodiment of a high acceleration rotary actuator
motor assembly, the assembly comprises a shaft carrying a first
phase motor element spaced a first distance from a second phase
motor element, a third phase motor element spaced a second distance
from the second phase motor element, and a fourth phase motor
element spaced a third distance from the third phase motor element,
each motor element including a square stator formed of four
interconnecting segmented stator elements, each segmented stator
element including a longitudinal member and a perpendicular member
connected as a unitary element, the longitudinal member having
parallel sides spaced apart by first and second ends, the
perpendicular member being orthogonal to the longitudinal member
and having an arcuate end opposite the longitudinal member, the
first end defines a receiving aperture and the second end includes
an attachment post, wherein the receiving aperture is adapted to
receive the receiving post of a second segmented stator element and
the attachment post is adapted to be received by the receiving
aperture of a third segmented stator element. A four pole winding
is provided in each stator of each phase motor element. A first
rotor is connected to the shaft in the first phase motor element, a
second rotor is connected to the shaft in the second phase motor
element, the second rotor being provided on the shaft .pi./8
radians offset from the first rotor, a third rotor is connected to
the shaft in the third phase motor element, the third rotor being
provided on the shaft .pi./4 radians offset from the first rotor,
and a fourth rotor is connected to the shaft in the fourth phase
motor element, the fourth rotor being provided on the shaft 3.pi./8
radians offset from the first rotor.
[0009] In another embodiment of a high acceleration rotary actuator
motor assembly, the assembly comprises a shaft carrying a first
phase motor element, a second phase motor element, and a third
phase motor element provided in tandem on the shaft, each motor
element including a square stator formed of four interconnecting
segmented stator elements, each segmented stator element including
a longitudinal member and a perpendicular member connected as a
unitary element, the longitudinal member having parallel sides
spaced apart by first and second ends, the perpendicular member
being orthogonal to the longitudinal member and having an arcuate
end opposite the longitudinal member, the first end defines a
receiving aperture and the second end includes an attachment post,
wherein the receiving aperture is adapted to receive the receiving
post of a second segmented stator element and the attachment post
is adapted to be received by the receiving aperture of a third
segmented stator element. A four pole winding is provided in each
stator of each phase motor element. A first rotor is connected to
the shaft in the first phase motor element, the first rotor
carrying four permanent magnets of a uniform radius and alternating
in exposed pole around the shaft. A second rotor is connected to
the shaft in the second phase motor element, the second rotor
carrying four permanent magnets of a uniform radius and alternating
in exposed pole around the shaft, the permanent magnets of the
second rotor being provided on the shaft .pi./6 radians offset from
the magnets of the first rotor. A third rotor is connected to the
shaft in the third phase motor element, the third rotor carrying
four permanent magnets of a uniform radius and alternating in
exposed pole around the shaft, the permanent magnets of the third
rotor being provided on the shaft .pi./3 radians offset from the
magnets of the first rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a plan view according to one or more examples of
embodiments of a high acceleration rotary actuator assembly,
showing the rotor and stator assemblies.
[0011] FIG. 2 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 1, showing a first
phase motor element taken along line 2-2 of FIG. 1.
[0012] FIG. 3 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the first phase
motor element of FIG. 2.
[0013] FIG. 4 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 1, showing a second
phase motor element taken along line 4-4 of FIG. 1.
[0014] FIG. 5 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the second phase
motor element of FIG. 4.
[0015] FIG. 6 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 1, showing a third
phase motor element taken along line 6-6 of FIG. 1.
[0016] FIG. 7 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the third phase
motor element of FIG. 6.
[0017] FIG. 8 is an overhead plan view of one or more examples of
embodiments of the high acceleration rotary actuator assembly of
FIG. 1.
[0018] FIG. 9 is an end view of the high acceleration rotary
actuator assembly of FIG. 8 with the end bell removed, showing one
or more electronic drive units in association with the multi-phase
tandem rotor servo motor assembly taken along line 9-9 of FIG.
8.
[0019] FIG. 10 is a plan view according to one or more examples of
embodiments of a high acceleration rotary actuator assembly,
showing the rotor and stator assemblies.
[0020] FIG. 11 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 10, showing a first
phase motor element taken along line 11-11 of FIG. 10.
[0021] FIG. 12 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the first phase
motor element of FIG. 11.
[0022] FIG. 13 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 10, showing a second
phase motor element taken along line 13-13 of FIG. 10.
[0023] FIG. 14 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the second phase
motor element of FIG. 13.
[0024] FIG. 15 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 10, showing a third
phase motor element taken along line 15-15 of FIG. 10.
[0025] FIG. 16 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the third phase
motor element of FIG. 15.
[0026] FIG. 17 is a cross-sectional view of a section of the high
acceleration rotary actuator assembly of FIG. 10, showing a fourth
phase motor element taken along line 17-17 of FIG. 10.
[0027] FIG. 18 is a graph showing the torque per amp versus rotor
angle for one revolution of the rotor provided in the fourth phase
motor element of FIG. 17.
[0028] FIG. 19 is an elevation view of one or more examples of
embodiments of a stator element segment used in association with
the stator phase elements of the high acceleration rotary actuator
assembly of FIGS. 1 and 10.
[0029] FIG. 20 is an elevation view of the stator element segment
of FIG. 19, showing winding provided on the stator element
segment.
[0030] FIG. 21 is an elevation view of a portion of one or more
examples of embodiments of the high acceleration rotary actuator
assembly of FIG. 1, showing heat conducting elements adapted to
extract heat from the stator lamination and winding end turns.
[0031] FIG. 22 is an elevation view of a portion of one or more
examples of embodiments of the high acceleration rotary actuator
assembly of FIG. 1, showing heat conducting elements having a
liquid cooling chamber adapted to extract heat from the stator
lamination and winding end turns.
[0032] FIG. 23 is a graph showing the motor torque rating (X-axis)
versus the torque to inertia ratio (Y-axis) comparing commercially
available low inertia servo motors with the high acceleration
rotary actuator assembly.
DETAILED DESCRIPTION
[0033] The invention shown in the Figures is generally directed to
a high acceleration rotary actuator assembly 100, 200, and in
particular a multi-phase tandem rotor servo motor assembly 102
having a plurality of electrically isolated phase motor elements
110, 120, 130, 140 formed of a plurality of segmented stator
elements 160 and provided in tandem upon a common shaft 104. For
ease of discussion and understanding, the following detailed
description and illustrations refer to each phase element 110, 120,
130, 140 of the multi-phase tandem rotor servo motor 102 as a
permanent magnet motor. It should be appreciated that a permanent
magnet motor is provided for purposes of illustration, and that the
multi-phase tandem rotor servo motor 102 and associated phase
elements 110, 120, 130, 140 disclosed herein may be employed as a
different type of motor, including, but not limited to, a
reluctance motor or induction motor.
[0034] FIG. 1 is a plan view of an embodiment of a high
acceleration rotary actuator assembly 100. The high acceleration
rotary actuator assembly 100 generally includes a multi-phase
tandem rotor servo motor assembly 102. The multi-phase tandem rotor
servo motor 102 may include a plurality of phases. For example, in
the embodiment illustrated in FIG. 1, the multi-phase tandem rotor
servo motor 102 may include three phases which are separated into
three phase motor elements, a first or A phase motor element 110, a
second or B phase motor element 120, and a third or C phase motor
element 130. Each phase motor element 110, 120, 130 includes a
respective input terminal connection or input lead 111, 121, 131,
which conveys an electrical current to each phase motor element
110, 120, 130 from a corresponding electronic drive unit 210, 220,
230 (see FIG. 8). Each phase motor element 110, 120, 130
additionally includes a respective output terminal connection or
output lead 112, 122, 132 which conveys an electrical current out
of or away from each phase motor element 110, 120, 130 to a
corresponding electronic drive unit 210, 220, 230 (see FIG. 8). The
input/output terminal connections 111/112, 121/122, 131/132 for
each phase motor element 110, 120, 130 are electrically isolated
from one another. In other words, the output terminal connections
112, 122, 132 are not tied together to form a neutral point. By
electrically isolating the terminal connections for each phase
motor element 110, 120, 130, each phase electronic drive unit 210,
220, 230 may more readily realize the desired optimum current
waveform for each respective phase motor element 110, 120, 130.
This in turn may assist in the realization of a high torque to
inertia ratio servo motor in accordance with the high acceleration
rotary actuator assembly 100 as disclosed herein.
[0035] The multi-phase tandem rotor servo motor 102 also includes a
low inertia, common shaft 104. The low inertia shaft 104 has a
lower inertia than shafts or rotors of comparable motors, as shaft
104 has a longer length and smaller diameter due to the tandem
arrangement of the phase motor elements 110, 120, 130. Each phase
motor element 110, 120, 130 is mounted on or connected in tandem to
shaft 104. As shown in FIG. 1, when connected to shaft 104, each
phase motor element 110, 120, 130 may be spaced or separated from
one another by a distance 150, 151. For example, the first phase
motor element 110 may be separated from the second stator phase
element 120 by a first distance or gap or spacing 150. Similarly,
the second phase motor element 120 may be separated from the third
phase motor element 130 by a second distance or gap or spacing 151.
In one or more examples of embodiments, the phase motor elements
110, 120, 130 may be provided in tandem on shaft 104 with minimal
to no spacing 150, 151 between the respective phase motor elements
110, 120, 130.
[0036] The high acceleration rotary actuator assembly 100 of FIG. 1
may also include end bells 105 (not shown in FIG. 1), a casing or
heat shrink tube 106 (not shown in FIG. 1) which encases or
surrounds the multi-phase tandem rotor servo motor 102, and one or
more bearing assembly 107 (not shown in FIG. 1) which may include a
bearing support or holder 108 and one or more associated bearings
109 (not shown in FIG. 1).
[0037] FIG. 2 illustrates a cross-sectional view of the first phase
motor element 110. The first phase motor element 110 includes a
plurality of interconnected stator segments or stator lamination
segments or segmented stator elements 160. As illustrated in FIG.
2, the first phase motor element 110 includes interconnected stator
segments 160a, 160b, 160c, 160d. Each stator segment 160a, 160b,
160c, 160d is provided approximately orthogonal to or at an
approximate ninety (90) degree angle to each of the neighboring
stator segments 160a, 160b, 160c, 160d. The interconnected stator
segments 160a, 160b, 160c, 160d form an approximately square stator
lamination 113. While FIG. 2 illustrates the cross-section of a
single stator lamination 113, the first phase motor element 110 may
include a stack or series or plurality of stator laminations 113.
For example, in various embodiments, a plurality of stator
laminations 113 may be stacked upon each other to form the first
phase motor element 110.
[0038] Each stator segment 160 may include a longitudinal member
161 and a perpendicular member 162. Referring to FIG. 2, each of
the interconnected stator segments 160a, 160b, 160c, 160d
respectively includes a longitudinal member or back iron 161a,
161b, 161c, 161d and a perpendicular member 162a, 162b, 162c, 162d.
The stator lamination 113 and associated longitudinal members or
back iron 161 are illustrated in FIG. 2 as arranged in an
approximate square shaped configuration. An approximate square
shaped configuration provides advantages over standard circular
stator lamination and/or back iron arrangements. An approximate
square shaped configuration provides a greater or increased amount
of back iron 161 in the stator lamination 113 than a standard
circular stator lamination. This may allow for an increased amount
of conductive material or winding (not shown) to be wound about
each stator segment 160. Further, the square shaped configuration
of the interconnected stator segments 160 allows for a larger slot
114 area. This may allow for an increased amount of conductive
material or winding (not shown) to be wound about each stator
segment 160 and placed in or through slots 114 than a standard
circular stator lamination, advantageously reducing heat generation
for a given torque and allowing for a higher torque and torque to
inertia ratio. Further, slots 114 may be provided toward the
corners of the stator lamination 113, providing for a reduction in
heat build-up in the stator lamination 113 due to the improved heat
transfer or heat dissipation or cooling. In various embodiments,
the stator lamination 113 may be rectangular or any other polygonal
arrangement which provides for an increased amount of back iron 161
in the stator lamination 113 than a standard circular stator
lamination. Stator lamination 113 may be formed from iron, steel, a
combination of iron and silicon, silicon steel, metallic alloys,
laminates or by any other known and suitable materials, processes
or methods.
[0039] The interconnected stator segments 160a, 160b, 160c, 160d
define a plurality of slots or winding slots or corner slots 114.
Referring to FIG. 2, the illustrated interconnected stator segments
160a, 160b, 160c, 160d define slots 114a, 114b, 114c, 114d. Each
slot 114 corresponds with one of four poles of the multi-phase
tandem servo motor 102. Accordingly, the four slots 114a, 114b,
114c, 114d define a four pole winding, for example a four pole
concentrated winding. The four slots 114a, 114b, 114c, 114d are
provided in an arrangement approximately orthogonal or
perpendicular to one another. For example, as shown in FIG. 2, slot
114a is neighbored by slots 114b and 114d, both of which are
provided approximately orthogonal to corner slot 114a. Similarly,
slot 114b is neighbored by slots 114a and 114c, both of which are
provided approximately orthogonal to corner slot 114b. Slot 114c is
neighbored by slots 114b and 114d, both of which are provided
approximately orthogonal to corner slot 114c. Slot 114d is
neighbored by slots 114c and 114a, both of which are provided
approximately orthogonal to corner slot 114d. To this end, the
slots 114a, 114b, 114c, 114d are provided in relation to one
another to approximately form the corners of a square. Each slot
114a, 114b, 114c, 114d alternates with its neighboring slot between
carrying an electrical current into the slot or carrying an
electrical current out of the slot through the respective winding
(not shown) wound about each stator segment 160a, 160b, 160c, 160d.
As illustrated in FIG. 2, slots 114a and 114c carry an electrical
current into the respective slots, which is illustrated by a "+" or
plus, while slots 114b and 114d carry an electrical current out of
the respective slots, which is illustrated by a "" or dot. In
addition, slot 114a receives the first input terminal connection
111, while the first output terminal connection 112 exits from slot
114b. In one or more examples of embodiments, slots 114 may be
circular, square, rectangular, or any other polygonal arrangement
or appropriate size to maximize conductive material or winding in
accordance with the present invention.
[0040] The interconnected stator segments 160a, 160b, 160c, 160d
may define one or more slot necks or slot passages 115. Referring
to FIG. 2, each slot 114a, 114b, 114c, 114d includes a slot neck
115a, 115b, 115c, 115d. Each slot neck 115 is defined by the
perpendicular members 162 of the respective interconnected stator
segments 160a, 160b, 160c, 160d bordering the respective slot 114.
For example, slot neck 115a is defined by perpendicular members
162a, 162d. Each slot neck 115 interconnects the slot 114 and the
rotor aperture 116.
[0041] The interconnected stator segments 160a, 160b, 160c, 160d
may define a rotor aperture 116. The rotor aperture 116 may be in
communication with corner slots 114a, 114b, 114c, 114d, for
example, as illustrated in FIG. 2, through slot openings 115a,
115b, 115c, 115d. In addition, rotor aperture 116 receives or
surrounds shaft 104.
[0042] Within rotor aperture 116, shaft 104 carries rotor or tandem
rotor or first rotor 180a. Mounted upon or connected to rotor 180a
is a plurality of magnets 117. Referring to FIG. 2, rotor 105a may
carry four magnets 117a, 117b, 117c, 117d. Magnets 117a, 117b,
117c, 117d are respectively provided about a portion of the
circumference of rotor 180a. In various embodiments, and as
illustrated in FIG. 2, the four magnets 117a, 117b, 117c, 117d are
each permanent magnets which are a full 90.degree. (ninety degree)
shape. In other words, the four magnets 117a, 117b, 117c, 117d each
extend along one-quarter of the circumference of the rotor 180a or
for 90.degree. (ninety degrees) of the radius of shaft 104 and
rotor 180a. Each neighboring magnet 117a, 117b, 117c, 117d
alternates its exposed pole, or pole opposite the rotor side of the
magnet, about the circumference of rotor 180a. For example, magnets
117a, 117b, 117c, 117d include alternating poles, where magnets
117a and 117c expose a north pole, which is illustrated by an "N",
while magnets 117b and 117d expose a south pole, which is
illustrated by an "S". In addition, magnets 117a, 117b, 117c, 117d
abut or border or communicate with each respective neighboring
magnet 117. To this end, magnets 117a, 117b, 117c, 117d have the
same thickness radially outward from shaft 104. In other words,
magnets 117a, 117b, 117c, 117d have a uniform or a continuous
thickness about the circumference of rotor 180a. The shaft 104,
rotor 180a and associated magnets 117a, 117b, 117c, 117d are spaced
a distance from rotor aperture 116 by an air gap 119. The air gap
119 enables the shaft 104, rotor 180a and magnets 117a, 117b, 117c,
117d to rotate unobstructed within the rotor aperture 116. As
observed from the cross-sectional view of FIG. 2, the shaft 104,
rotor 180a and magnets 117a, 117b, 117c, 117d rotate
counter-clockwise within rotor aperture 116. In one or more
examples of embodiments, magnets 117 may include angled edges,
tapered edges, or any suitable edge for operation of the high
acceleration rotary actuator assembly 100 in accordance with the
present invention.
[0043] FIG. 3 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180a about the rotor
aperture 116 of the first phase motor element 110. The torque per
amp versus rotor angle of the first phase motor element 110 is in
the shape of a square or approximate square wave. The square wave
is generated by the continuous or uniform thickness of magnets 117
about rotor 180a in air gap 119 of the rotor aperture 116. Based
upon the four magnetic poles (or two pole pairs) of the first phase
motor element 110, the torque per amp versus rotor angle completes
two electrical cycles for every one revolution or 360.degree.
(three-hundred and sixty degrees) of rotation of rotor 180a. The
first electrical cycle is completed at 180.degree. (one-hundred and
eighty degrees) or .pi. (pie) radians of rotation of rotor 180a,
while the second electrical cycle is completed at 360.degree.
(three-hundred and sixty degrees) or 2.pi. (two pie) radians of
rotation of rotor 180a.
[0044] FIG. 4 illustrates a cross-sectional view of the second
phase motor element 120 of the multi-phase tandem rotor servo motor
assembly 102. The second phase motor element 120 includes a
plurality of interconnected stator segments 160a, 160b, 160c, 160d,
an approximately square stator lamination 113, a plurality of slots
114, slot necks 115, rotor aperture 116, magnets 117 and air gap
119 which are substantially as described herein in association with
the first phase motor element 110. Operation and particular
components described herein are substantially the same and like
numbers have been used to illustrate the like components. Slot 114a
of the second phase motor element 120 receives the second input
terminal connection 121, while the second output terminal
connection 122 exits from slot 114b. Within the rotor aperture 116
of the second phase motor element 120, common shaft 104 carries
rotor 180b. Mounted upon or connected to rotor 180b is a plurality
of magnets 117. As illustrated in FIG. 4, rotor 180b carries four
magnets 117a, 117b, 117c, 117d. Rotor 180b and the attached magnets
117a, 117b, 117c, 117d are substantially the same as those
described in association with rotor 180a, but for the positioning
of rotor 180b in relation to rotor 180a on shaft 104. Rotor 180b is
provided on shaft 104 approximately 30.degree. (thirty degrees)
mechanically lagging from rotor 180a. In other words, comparing the
cross-sectional view of the first phase motor element 110 of FIG. 2
to the cross-sectional view of the second phase motor element 120
of FIG. 4, rotor 180b (and the associated magnets 117) is
illustrated as offset or rotated from rotor 180a (and the
associated magnets 117) by approximately 30.degree. (thirty
degrees) lagging. Put differently, according to the illustrated
view of FIG. 4, rotor 180b (and the associated magnets 117) is
disposed about shaft 104 approximately 30.degree. (thirty degrees)
in the clockwise direction as compared to rotor 180a (of FIG. 2),
as FIGS. 2 and 4 illustrate the rotation of shaft 104 as in the
counter-clockwise direction. In addition to rotor 180b mechanically
lagging rotor 180a by approximately 30.degree. (thirty degrees),
rotor 180b has an electrical angle which is lagging rotor 180a by
approximately 60.degree. (sixty degrees). The associated electrical
angle of rotor 180b can be calculated by multiplying the mechanical
angle by N, where N equals the number of pole pairs (or one-half
the total number of poles).
[0045] FIG. 5 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180b about the rotor
aperture 116 of the second phase motor element 120. The torque per
amp versus rotor angle of the second phase motor element 120 is in
the shape of a square or approximate square wave. The square wave
is generated by the continuous or uniform thickness of magnets 117
about rotor 180b in air gap 119 of the rotor aperture 116. Based
upon the four magnetic poles (or two pole pairs) of the second
phase motor element 120, the torque per amp versus rotor angle
completes two electrical cycles for every one revolution or
360.degree. (three-hundred and sixty degrees) of rotation of rotor
180b. The first electrical cycle is completed at 180.degree.
(one-hundred and eighty degrees) or .pi. (pie) radians of rotation
of rotor 180b, while the second electrical cycle is completed at
360.degree. (three-hundred and sixty degrees) or 2.pi. (two pie)
radians of rotation of rotor 180b. Comparing torque per amp versus
rotor angle of FIG. 5 to FIG. 3, the torque per amp of FIG. 5 is
shifted 30.degree. (thirty degrees) mechanically lagging to the
torque per amp of FIG. 3. In other words, the torque per amp curve
of FIG. 5 is shifted .pi./6 radians to the right as compared to the
torque per amp curve of FIG. 3. This is due to rotor 180b being
rotated about shaft 104 30.degree. (thirty degrees) behind, or
lagging, rotor 180a.
[0046] FIG. 6 illustrates a cross-sectional view of the third phase
motor element 130 of the multi-phase tandem rotor servo motor
assembly 102. The third phase motor element 130 includes a
plurality of interconnected stator segments 160a, 160b, 160c, 160d,
an approximately square stator lamination 113, a plurality of slots
114, slot necks 115, rotor aperture 116, magnets 117 and air gap
119 which are substantially as described herein in association with
the first phase motor element 110. Operation and particular
components described herein are substantially the same and like
numbers have been used to illustrate the like components. Slot 114a
of the third phase motor element 130 receives the third input
terminal connection 131, while the third output terminal connection
132 exits from slot 114b. Within the rotor aperture 116 of the
third phase motor element 130, common shaft 104 carries rotor 180c.
Mounted upon or connected to rotor 180c is a plurality of magnets
117. As illustrated in FIG. 6, rotor 180c carries four magnets
117a, 117b, 117c, 117d. Rotor 180c and the attached magnets 117a,
117b, 117c, 117d are substantially the same as those described in
association with rotor 180a, but for the positioning of rotor 180c
in relation to rotor 180a on shaft 104. Rotor 180c is provided on
shaft 104 approximately 60.degree. (sixty degrees) mechanically
lagging from rotor 180a. In other words, comparing the
cross-sectional view of the first phase motor element 110 of FIG. 2
to the cross-sectional view of the third phase motor element 130 of
FIG. 6, rotor 180c (and the associated magnets 117) is illustrated
as offset or rotated from rotor 180a (and the associated magnets
117) by approximately 60.degree. (sixty degrees) lagging. Put
differently, according to the illustrated view of FIG. 6, rotor
180c (and the associated magnets 117) is disposed about shaft 104
approximately 60.degree. (sixty degrees) in the clockwise direction
as compared to rotor 180a (of FIG. 2), as FIGS. 2 and 6 illustrate
the rotation of shaft 104 as in the counter-clockwise direction. In
addition to rotor 180c mechanically lagging rotor 180a by
approximately 60.degree. (sixty degrees), rotor 180c has an
electrical angle which is lagging rotor 180a by approximately
120.degree. (one hundred and twenty degrees). The associated
electrical angle of rotor 180c can be calculated by multiplying the
mechanical angle by N, where N equals the number of pole pairs (or
one-half the total number of poles).
[0047] FIG. 7 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180c about the rotor
aperture 116 of the third phase motor element 130. The torque per
amp versus rotor angle of the third phase motor element 130 is in
the shape of a square or approximate square wave. The square wave
is generated by the continuous or uniform thickness of magnets 117
about rotor 180c in air gap 119 of the rotor aperture 116. Based
upon the four magnetic poles (or two pole pairs) of the third phase
motor element 130, the torque per amp versus rotor angle completes
two electrical cycles for every one revolution of rotor 180c. The
first electrical cycle is completed at 180.degree. (one-hundred and
eighty degrees) or .pi. (pie) radians of rotation of rotor 180c,
while the second electrical cycle is completed at 360.degree.
(three-hundred and sixty degrees) or 2.pi. (two pie) radians of
rotation of rotor 180c. Comparing torque per amp versus rotor angle
of FIG. 7 to FIG. 3, the torque per amp of FIG. 7 is shifted
60.degree. (sixty degrees) mechanically lagging to the torque per
amp of FIG. 3. In other words, the torque per amp curve of FIG. 7
is shifted .pi./3 radians to the right as compared to the torque
per amp curve of FIG. 3. This is due to rotor 180c being rotated
about shaft 104 60.degree. (sixty degrees) behind, or lagging,
rotor 180a.
[0048] FIG. 8 is an overhead view of one or more examples of
embodiments of the high acceleration rotary actuator assembly 100.
Referring to FIG. 8, the high acceleration rotary actuator assembly
100 includes the multi-phase tandem rotor servo motor assembly 102
encased or surrounded by a casing or heat shrink tube 106. Shaft
104 is provided through a portion of casing 106. Shaft 104 may
include an end 145 adapted to engage or connect to a drive shaft or
other component for the transmission of torque and/or rotational
force from the high acceleration rotary actuator assembly 100 to a
desired assembly, for example a drive train, a pump, or other
suitable mechanical assembly. End bells 105, for example a first
end bell 105a and a second end bell 105b, may be provided on either
end of shaft 104 and casing 106. Phase motor elements 110, 120, 130
may be mounted on or about a portion of shaft 104. The phase motor
elements 110, 120, 130 are substantially as described herein in
association with the phase motor elements 110, 120, 130 illustrated
in FIGS. 2-7. Operation and particular components described herein
are substantially the same and like numbers have been used to
illustrate the like components. The phase motor elements 110, 120,
130 may include winding (not shown) having winding end turns 171.
Rotors 180a, 180b, 180c are provided on shaft 104 in association
with each respective phase motor element 110, 120, 130. Each rotor
180 may include magnet assemblies 181, 182. The magnet assemblies
181, 182 may be mounted upon or connected to rotor 180 and each may
include a plurality of magnets 117. For example, each magnet
assembly 181a/182a, 181b/182b, 181c/182c may include four magnets
117a, 117b, 117c, 117d, substantially as described herein in
association with the phase motor elements 110, 120, 130 illustrated
in FIGS. 2-7.
[0049] The multi-phase tandem rotor servo motor assembly 102 may
include a bearing assembly 107. The bearing assembly 107 may
include a bearing holder 108 and a bearing 109. As illustrated in
FIG. 8, a plurality of bearing assemblies 107 are provided on rotor
104, one between each phase motor element 110, 120, 130 and one on
each end of the casing 106 in association with end bells 105a, b.
In one or more examples of embodiments, the multi-phase tandem
rotor servo motor assembly 102 may include only a single bearing
assembly 107, bearing holder 108 and/or bearing 109. Further, it
should be appreciated in one or more examples of embodiments that
the multi-phase tandem rotor servo motor assembly 102 may not
include any bearing assemblies 107, bearing holders 108 and/or
bearings 109.
[0050] As illustrated in FIG. 8, the high acceleration rotary
actuator assembly 100 may include a plurality of electronic drive
units 210, 220, 230. Each drive unit 210, 220, 230 is respectively
in communication with an associated phase motor element 110, 120,
130 through input/output terminal connections 111/112, 121/122,
131/132 (see FIG. 1). Each phase motor element 110, 120, 130 and
the associated drive unit 210, 220, 230 is electrically isolated
from one another. For example, input terminal connection 111 is in
communication with the first or A phase drive unit 210 to convey an
electrical current of a first phase from the drive unit 210 to the
first or A phase motor element 110. Output terminal connection 112
is in communication with drive unit 210 to convey an electrical
current from the first phase motor element 110 to the drive unit
210. Input terminal connection 121 is in communication with second
or B phase drive unit 220 to convey an electrical current of a
second phase from the drive unit 220 to the second or B phase motor
element 120. Output terminal connection 122 is in communication
with drive unit 220 to convey an electrical current from the second
phase motor element 120 to the drive unit 220. Input terminal
connection 131 is in communication with third or C phase drive unit
230 to convey an electrical current of a third phase from the drive
unit 230 to the third or C phase motor element 130. Output terminal
connection 132 is in communication with drive unit 230 to convey an
electrical current from the third phase motor element 130 to the
drive unit 230.
[0051] Referring to FIG. 9, an end view of one or more examples of
embodiments of the high acceleration rotary actuator assembly 100
is provided with the end bell 105a removed illustrating the
multi-phase tandem rotor servo motor assembly 102 with shaft 104
there through. The electronic drive units 210, 220, 230 are
provided a distance offset from and in communication with the
multi-phase tandem rotor servo motor assembly 102 through
input/output terminal connections 111/112, 121/122, 131/132 (not
shown, see FIG. 1). In the embodiment illustrated in FIG. 9, casing
106 is approximately rectangular with the multi-phase tandem rotor
servo motor assembly 102 provided alongside and approximately
parallel to the electronic drive units 210, 220, 230. It should be
appreciated that casing 106 may be any polygonal shape or
arrangement suitable for operation and use of the high acceleration
rotary actuator assembly 100. Further, in one or more examples of
embodiments, the electronic drive units 210, 220, 230 may be
provided at an alternative position in relation to the multi-phase
tandem rotor servo motor assembly 102, for example, including, but
not limited to, above, below, at an angle to, or at any other
desired position in relation to the multi-phase tandem rotor servo
motor assembly 102.
[0052] An alternative embodiment of the high acceleration rotary
actuator assembly 200 is shown in FIGS. 10-18. The high
acceleration rotary actuator assembly 200 includes features which
are substantially as described herein in association with the high
acceleration rotary actuator assembly 100. Operation and particular
components described herein are substantially the same and like
numbers have been used to illustrate the like components. Referring
to FIG. 10, in this embodiment, the multi-phase tandem rotor servo
motor assembly 102 includes four phases which are separated into
four phase motor elements, a first or A phase motor element 110, a
second or B phase motor element 120, a third or C phase motor
element 130 and a fourth or D phase motor element 140. Each phase
motor element 110, 120, 130, 140 is provided on or about rotating
shaft 104. Each phase motor element 110, 120, 130, 140 includes a
respective input terminal connection or input lead 111, 121, 131,
141, each of which convey a respective electrical current to the
respective phase motor element 110, 120, 130, 140 from a
corresponding electronic drive unit 210, 220, 230, 240 (not shown).
Each phase motor element 110, 120, 130, 140 additionally includes a
respective output terminal connection or output lead 112, 122, 132,
142 which conveys a respective electrical current out of or away
from each respective phase motor element 110, 120, 130, 140 to a
corresponding electronic drive unit 210, 220, 230, 240 (not shown).
The input/output terminal connections 111/112, 121/122, 131/132,
141/142 for each phase motor element 110, 120, 130, 140 are
electrically isolated from one another. In other words, the output
terminal connections 112, 122, 132, 142 are not tied together to
form a neutral point.
[0053] FIG. 11 illustrates a cross-sectional view of the first
phase motor element 110 of the multi-phase tandem rotor servo motor
assembly 102 of the high acceleration rotary actuator assembly 200.
The first phase motor element 110 includes a plurality of
interconnected stator segments 160a, 160b, 160c, 160d, an
approximately square stator lamination 113, a plurality of slots
114, slot necks 115, rotor aperture 116, magnets 117, air gap 119,
shaft 104 and rotor 180a which are substantially as described
herein in association with the first phase motor element 110
illustrated in FIG. 2. Operation and particular components
described herein are substantially the same and like numbers have
been used to illustrate the like components.
[0054] FIG. 12 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180a about the rotor
aperture 116 of the first phase motor element 110. The torque per
amp versus rotor angle of the first phase motor element 110 is in
the shape of a square or approximate square wave. The square wave
is generated by the continuous or uniform thickness of magnets 117
about rotor 180a in air gap 119 of the rotor aperture 116. Based
upon the four magnetic poles (or two pole pairs) of the first phase
motor element 110, the torque per amp versus rotor angle completes
two electrical cycles for every one revolution or 360.degree.
(three-hundred and sixty degrees) of rotation of rotor 180a. The
first electrical cycle is completed at 180.degree. (one-hundred and
eighty degrees) or .pi. (pie) radians of rotation of rotor 180a,
while the second electrical cycle is completed at 360.degree.
(three-hundred and sixty degrees) or 2.pi. (two pie) radians of
rotation of rotor 180a.
[0055] FIG. 13 illustrates a cross-sectional view of the second
phase motor element 120 of the multi-phase tandem rotor servo motor
assembly 102 of the high acceleration rotary actuator assembly 200.
The second phase motor element 120 includes a plurality of
interconnected stator segments 160a, 160b, 160c, 160d, an
approximately square stator lamination 113, a plurality of slots
114, slot necks 115, rotor aperture 116, magnets 117 and air gap
119 which are substantially as described herein in association with
the first phase motor element 110 of FIG. 2. Operation and
particular components described herein are substantially the same
and like numbers have been used to illustrate the like components.
Within the rotor aperture 116 of the second phase motor element
120, common shaft 104 carries rotor 180b. Mounted upon or connected
to rotor 180b is a plurality of magnets 117. As illustrated in FIG.
13, rotor 180b carries four magnets 117a, 117b, 117c, 117d. Rotor
180b and the attached magnets 117a, 117b, 117c, 117d are
substantially the same as those described in association with rotor
180a, but for the positioning of rotor 180b in relation to rotor
180a on shaft 104. Rotor 180b is provided on shaft 104
approximately 22.5.degree. (twenty-two point five degrees)
mechanically lagging from rotor 180a. In other words, comparing the
cross-sectional view of the first phase motor element 110 of FIG.
11 to the cross-sectional view of the second phase motor element
120 of FIG. 13, rotor 180b (and the associated magnets 117) is
illustrated as offset or rotated from rotor 180a (and the
associated magnets 117) by approximately 22.5.degree. (twenty-two
point five degrees) lagging. Put differently, according to the
illustrated view of FIG. 13, rotor 180b (and the associated magnets
117) is disposed about shaft 104 approximately 22.5.degree.
(twenty-two point five degrees) in the clockwise direction as
compared to rotor 180a (of FIG. 11), as FIGS. 11 and 13 illustrate
the rotation of shaft 104 as in the counter-clockwise direction. In
addition to rotor 180b mechanically lagging rotor 180a by
approximately 22.5.degree. (twenty-two point five degrees), rotor
180b has an electrical angle which is lagging rotor 180a by
approximately 45.degree. (forty five degrees). The associated
electrical angle of rotor 180b can be calculated by multiplying the
mechanical angle by N, where N equals the number of pole pairs (or
one-half the total number of poles).
[0056] FIG. 14 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180b about the rotor
aperture 116 of the second phase motor element 120 of FIG. 13. The
torque per amp versus rotor angle of the second phase motor element
120 is in the shape of a square or approximate square wave. The
square wave is generated by the continuous or uniform thickness of
magnets 117 about rotor 180b in air gap 119 of the rotor aperture
116. Based upon the four magnetic poles (or two pole pairs) of the
second phase motor element 120, the torque per amp versus rotor
angle completes two electrical cycles for every one revolution or
360.degree. (three-hundred and sixty degrees) of rotation of rotor
180b. The first electrical cycle is completed at 180.degree.
(one-hundred and eighty degrees) or .pi. (pie) radians of rotation
of rotor 180b, while the second electrical cycle is completed at
360.degree. (three-hundred and sixty degrees) or 2.pi. (two pie)
radians of rotation of rotor 180b. Comparing torque per amp versus
rotor angle of FIG. 14 to FIG. 12, the torque per amp of FIG. 14 is
shifted 22.5.degree. (twenty-two point five degrees) mechanically
lagging to the torque per amp of FIG. 12. In other words, the
torque per amp curve of FIG. 14 is shifted .pi./8 radians to the
right as compared to the torque per amp curve of FIG. 12. This is
due to rotor 180b being rotated about shaft 104 22.5.degree.
(twenty-two point five degrees) behind, or lagging, rotor 180a.
[0057] FIG. 15 illustrates a cross-sectional view of the third
phase motor element 130 of the multi-phase tandem rotor servo motor
assembly 102 of the high acceleration rotary actuator assembly 200.
The third phase motor element 130 includes a plurality of
interconnected stator segments 160a, 160b, 160c, 160d, an
approximately square stator lamination 113, a plurality of slots
114, slot necks 115, rotor aperture 116, magnets 117 and air gap
119 which are substantially as described herein in association with
the first phase motor element 110 of FIG. 2. Operation and
particular components described herein are substantially the same
and like numbers have been used to illustrate the like components.
Within the rotor aperture 116 of the third phase motor element 130,
common shaft 104 carries rotor 180c. Mounted upon or connected to
rotor 180c is a plurality of magnets 117. As illustrated in FIG.
15, rotor 180c carries four magnets 117a, 117b, 117c, 117d. Rotor
180c and the attached magnets 117a, 117b, 117c, 117d are
substantially the same as those described in association with rotor
180a, but for the positioning of rotor 180c in relation to rotor
180a on shaft 104. Rotor 180c is provided on shaft 104
approximately 45.degree. (forty five degrees) mechanically lagging
from rotor 180a. In other words, comparing the cross-sectional view
of the first phase motor element 110 of FIG. 11 to the
cross-sectional view of the third phase motor element 130 of FIG.
15, rotor 180c (and the associated magnets 117) is illustrated as
offset or rotated from rotor 180a (and the associated magnets 117)
by approximately 45.degree. (forty five degrees) lagging. Put
differently, according to the illustrated view of FIG. 15, rotor
180c (and the associated magnets 117) is disposed about shaft 104
approximately 45.degree. (forty five degrees) in the clockwise
direction as compared to rotor 180a (of FIG. 11), as FIGS. 11 and
15 illustrate the rotation of shaft 104 as in the counter-clockwise
direction. In addition to rotor 180c mechanically lagging rotor
180a by approximately 45.degree. (forty five degrees), rotor 180c
has an electrical angle which is lagging rotor 180a by
approximately 90.degree. (ninety degrees). The associated
electrical angle of rotor 180c can be calculated by multiplying the
mechanical angle by N, where N equals the number of pole pairs (or
one-half the total number of poles).
[0058] FIG. 16 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180c about the rotor
aperture 116 of the third phase motor element 130 of FIG. 15. The
torque per amp versus rotor angle of the third phase motor element
130 is in the shape of a square or approximate square wave. The
square wave is generated by the continuous or uniform thickness of
magnets 117 about rotor 180c in air gap 119 of the rotor aperture
116. Based upon the four magnetic poles (or two pole pairs) of the
third phase motor element 130, the torque per amp versus rotor
angle completes two electrical cycles for every one revolution or
360.degree. (three-hundred and sixty degrees) of rotation of rotor
180c. The first electrical cycle is completed at 180.degree.
(one-hundred and eighty degrees) or .pi. (pie) radians of rotation
of rotor 180c, while the second electrical cycle is completed at
360.degree. (three-hundred and sixty degrees) or 2.pi. (two pie)
radians of rotation of rotor 180c. Comparing torque per amp versus
rotor angle of FIG. 16 to FIG. 12, the torque per amp of FIG. 16 is
shifted 45.degree. (forty five degrees) mechanically lagging to the
torque per amp of FIG. 12. In other words, the torque per amp curve
of FIG. 16 is shifted .pi./4 radians to the right as compared to
the torque per amp curve of FIG. 12. This is due to rotor 180c
being rotated about shaft 104 45.degree. (forty five degrees)
behind, or lagging, rotor 180a.
[0059] FIG. 17 illustrates a cross-sectional view of the fourth
phase motor element 140 of the multi-phase tandem rotor servo motor
assembly 102 of the high acceleration rotary actuator assembly 200.
The fourth phase motor element 140 includes a plurality of
interconnected stator segments 160a, 160b, 160c, 160d, an
approximately square stator lamination 113, a plurality of slots
114, slot necks 115, rotor aperture 116, magnets 117 and air gap
119 which are substantially as described herein in association with
the first phase motor element 110 of FIG. 2. Operation and
particular components described herein are substantially the same
and like numbers have been used to illustrate the like components.
Slot 114a of the fourth phase motor element 140 receives the fourth
input terminal connection 141, while the second output terminal
connection 142 exits from slot 114b. Within the rotor aperture 116
of the fourth phase motor element 140, common shaft 104 carries
rotor 180d. Mounted upon or connected to rotor 180d is a plurality
of magnets 117. As illustrated in FIG. 4, rotor 180d carries four
magnets 117a, 117b, 117c, 117d. Rotor 180d and the attached magnets
117a, 117b, 117c, 117d are substantially the same as those
described in association with rotor 180a, but for the positioning
of rotor 180d in relation to rotor 180a on shaft 104. Rotor 180d is
provided on shaft 104 approximately 67.5.degree. (sixty seven point
five degrees) mechanically lagging from rotor 180a. In other words,
comparing the cross-sectional view of the first phase motor element
110 of FIG. 11 to the cross-sectional view of the fourth phase
motor element 140 of FIG. 17, rotor 180d (and the associated
magnets 117) is illustrated as offset or rotated from rotor 180a
(and the associated magnets 117) by approximately 67.5.degree.
(sixty seven point five degrees) lagging. Put differently,
according to the illustrated view of FIG. 17, rotor 180d (and the
associated magnets 117) is disposed about shaft 104 approximately
67.5.degree. (sixty seven point five degrees) in the clockwise
direction as compared to rotor 180a (of FIG. 11), as FIGS. 11 and
17 illustrate the rotation of shaft 104 as in the counter-clockwise
direction. In addition to rotor 180d mechanically lagging rotor
180a by approximately 67.5.degree. (sixty seven point five
degrees), rotor 180d has an electrical angle which is lagging rotor
180a by approximately 135.degree. (one hundred and thirty five
degrees). The associated electrical angle of rotor 180d can be
calculated by multiplying the mechanical angle by N, where N equals
the number of pole pairs (or one-half the total number of
poles).
[0060] FIG. 18 illustrates a graphical representation of the angle
of rotation of the rotor, .theta..sub.r (X-axis) versus the torque
per amp (Y-axis) for one revolution of rotor 180d about the rotor
aperture 116 of the fourth phase motor element 140 of FIG. 17. The
torque per amp versus rotor angle of the fourth phase motor element
140 is in the shape of a square or approximate square wave. The
square wave is generated by the continuous or uniform thickness of
magnets 117 about rotor 180d in air gap 119 of the rotor aperture
116. Based upon the four magnetic poles (or two pole pairs) of the
fourth phase motor element 140, the torque per amp versus rotor
angle completes two electrical cycles for every one revolution or
360.degree. (three-hundred and sixty degrees) of rotation of rotor
180d. The first electrical cycle is completed at 180.degree.
(one-hundred and eighty degrees) or .pi. (pie) radians of rotation
of rotor 180d, while the second electrical cycle is completed at
360.degree. (three-hundred and sixty degrees) or 2.pi. (two pie)
radians of rotation of rotor 180d. Comparing torque per amp versus
rotor angle of FIG. 18 to FIG. 12, the torque per amp of FIG. 18 is
shifted 67.5.degree. (sixty seven point five degrees) mechanically
lagging to the torque per amp of FIG. 12. In other words, the
torque per amp curve of FIG. 18 is shifted 3.pi./8 radians to the
right as compared to the torque per amp curve of FIG. 12. This is
due to rotor 180d being rotated about shaft 104 67.5.degree. (sixty
seven point five degrees) behind, or lagging, rotor 180a.
[0061] It should be appreciated in one or more examples of
embodiments that the high acceleration rotary actuator assembly 100
may include a few as two phase motor elements or five or more phase
motor elements provided in tandem on a shaft 104. In one or more
examples of embodiments of the high acceleration rotary actuator
assembly 100 having two phase motor elements, each phase motor
element may be substantially as described herein in association
with the first phase motor element 110 of FIG. 2, but for the
positioning of the respective rotors 180 on shaft 104. For example,
the rotors 180 on shaft 104 are offset from one another by
approximately 45.degree. (forty five degrees), wherein one rotor is
mechanically lagging the other rotor. Further, the mechanically
lagging rotor has an electrical angle which is lagging the other
rotor by approximately 90.degree. (ninety degrees), wherein the
electrical angle is calculated by multiplying the mechanical angle
by N, where N equals the number of pole pairs (or one-half the
total number of poles). In addition, in one or more examples of
embodiments of the high acceleration rotary actuator assembly 100
having five phase motor elements, each phase motor element may be
substantially as described herein in association with the first
phase motor element 110 of FIG. 2, but for the positioning of the
respective rotors 180 on shaft 104. The rotors 180 of each
successive phase motor element on shaft 104 are offset from the
next successive phase motor element rotor by approximately
15.degree. (fifteen degrees), wherein each successive phase motor
element rotor is mechanically lagging the previous phase motor
element rotor. Further, each mechanically lagging rotor has an
electrical angle which is lagging the previous phase motor element
rotor by approximately 30.degree. (thirty degrees). To this end, in
one or more examples of embodiments, the high acceleration rotary
actuator assembly 100 may include X number of phases or phase motor
elements provided in tandem on a shaft 104, wherein the offset or
mechanical lagging of the rotors between each phase motor element
is calculated by 90.degree./X (ninety degrees divided by the number
of phases or phase motor elements).
[0062] FIG. 19 illustrates one or more examples of embodiments of a
stator element segment 160. The stator element segment 160 may
include a longitudinal member 161. The longitudinal member 161 may
include a first side 163 opposing a second side 164. In various
embodiments, the first side 163 and second side 164 may be provided
substantially parallel to one another. The first and second sides
163, 164 of the longitudinal member 161 may be spaced apart by a
first end 165 and a second end 166. The first and second ends 165,
166 of the longitudinal member 161 may be opposing ends. In various
embodiments, the first and second ends 165, 166 may be provided at
an angle .alpha. (alpha) formed between the respective first and
second ends 165, 166 and an imaginary line 167 extending between
and approximately perpendicular to the first and second sides 163,
164 of the longitudinal member 161. For example, as illustrated in
FIG. 19, the first and second ends 165, 166 may be provided at an
angle .alpha. (alpha) which is approximately a 45.degree. (forty
five degree) angle between the first and second ends 165, 166 and
the imaginary line 167 extending between and approximately
perpendicular to the first and second sides 163, 164 of the
longitudinal member 161. The first and second ends 165, 166 may
intersect the first side 163 at a first lip 168. As shown in FIG.
19, the first lip 168 may be provided at an angle to the first side
163, such that the first lip 168 is rounded or has an angle of
curvature or extends away from the first side 163 toward the second
side 164. Further, the first and second ends 165, 166 may intersect
the second side 164 at a second lip 169. As shown in FIG. 19, the
second lip 169 may be provided at an angle to the second side 164,
such that the second lip 169 is rounded or has an angle of
curvature or extends away from the second side 164 in a direction
away the first side 163. The first end 165 may define a receiving
aperture or recess 190, while the second end 166 may include an
attachment post 191. The receiving aperture 190 of the first end
165 is adapted to receive an attachment post 191 of a second end
166. For example, the receiving aperture 190 of the first end 165
illustrated in FIG. 19 may receive a corresponding attachment post
191 on the second end 166 of another, separate stator element
segment 160. Similarly, the attachment post 191 of the second end
166 illustrated in FIG. 19 may engage or be received by a
corresponding receiving aperture 190 on a first end 165 of another,
separate stator element segment 160. In this way, separate stator
element segments 160 may engage one another or interconnect to form
an approximately square segmented stator lamination stack 113, as
described in association with phase motor elements 110, 120, 130,
140. The longitudinal member 161 may define or include an alignment
hole or bolt hole 189. The alignment hole 189 may be used to align
a plurality of stacked stator element segments 160. In addition,
the alignment hole 189 may receive a bolt (not shown) to connect a
plurality of stacked stator element segments 160 to one another or
to a respective phase motor element 110, 120, 130, 140.
[0063] The stator element segment 160 may also include a
perpendicular member 162. As illustrated in FIG. 19, the
perpendicular member 162 is provided approximately perpendicular to
longitudinal member 161. The perpendicular member 162 may intersect
the longitudinal member 161 at approximately the mid-point of the
longitudinal member 161. In one or more examples of embodiments,
the longitudinal member 161 and perpendicular member 162 are
integrally formed or unitary. Further, in one or more examples of
embodiments and as illustrated in FIG. 19, the longitudinal member
161 and perpendicular member 162 may form an approximate T-shape or
are provided in the shape of the letter "T."
[0064] The perpendicular member 162 may include a first border 194
and a second border 195. The first and second borders 194, 195 may
be provided approximately parallel to one another. Further, the
first and second borders 194, 195 may be approximately
perpendicular to the longitudinal member 161, first side 163 and
second side 164. As shown in FIG. 19, the distance between the
first and second borders 194, 195 may be less than half of the
distance between the first and second ends 165, 166, or length, of
longitudinal member 161. The perpendicular member 162 may also
include an arcuate end 198 opposite the longitudinal member 161.
The arcuate end 198 may include a first tooth 199a and a second
tooth 199b. The first tooth 199a intersects the arcuate end 198 and
the first border 194, while the second tooth 199b intersects the
arcuate end 198 and the second border 195. It should be appreciated
that when a plurality of stator element segments 160 interconnect
to form the approximately square segmented stator lamination stack
113 as described in association with phase motor elements 110, 120,
130, 140, the arcuate ends 198 define the rotor aperture 116, while
the second side 164 of the longitudinal member 161 and the first
and second borders 194, 195 of the perpendicular member 162 define
slots 114.
[0065] FIG. 20 illustrates a stator element segment 160 having
winding 170 provided thereon. The winding 170 is a single,
continuous wire which is wound around the perpendicular member 162
of the stator element segment 160. Once a stator element segment
160 has received the desired amount of winding 170, the single,
continuous wire is wound around another stator element segment 160.
Accordingly, a plurality of stator element segments 160 are
interconnected by winding 170, as the winding 170 is the same,
contiguous wire. To this end, a plurality of stator element
segments 160 may be wound with winding 170 formed of the same,
contiguous wire. The plurality of wound stator element segments 160
may subsequently be interconnected to form the approximately square
segmented stator lamination stack 113 as described in association
with phase motor elements 110, 120, 130, 140. By winding a complete
phase made of segmented stator elements 160 with a winding 170 of a
single, contiguous wire as described herein provides advantages. By
using a single, contiguous wire, potentially unreliable solder
joints are excluded from the winding 170. Further, segmented stator
elements 160 provides for improved slot fill, as an increased
amount of conductor volume or wire may be placed in the slot,
reducing the heat generated in the winding 170 for a given torque
and resulting in a higher torque value and an increase in torque to
inertia ratio. In addition, an increase in slot fill reduces end
turn waste.
[0066] FIG. 21 illustrates a portion of the high acceleration
rotary actuator assembly 100, including the first phase and second
phase motor elements 110, 120. The phase motor elements 110, 120
include the elements substantially as described herein in
association with the first phase motor element 110 illustrated in
FIG. 2 and second phase motor element 120 illustrated in FIG. 4,
including a plurality of interconnected stator segments 160a, 160b,
160c, 160d, an approximately square stator lamination 113, a
plurality of slots 114, slot necks 115, rotor aperture 116, magnets
117, air gap 119, shaft 104 and rotor 180. Operation and particular
components described herein are substantially the same and like
numbers have been used to illustrate the like components. Referring
to FIG. 21, the motor elements 110, 120 are surrounded by heat
shrunk tube or casing 106. Stator laminations 113 have winding
which includes winding end turns 171. Heat conducting elements 300
are provided in communication with the stator laminations 113 and
winding end turns 171 to conduct or remove heat away from the
respective stator laminations 113 and winding end turns 171. The
heat conducting elements 300 may be formed of a thermally
conductive insulation compound, for example, but not limited to,
aluminum, carbon graphite, a carbon graphite laminate, copper,
ceramic, or any other known or future developed material suitable
to conduct heat away from the stator laminations 113 and/or winding
end turns 171.
[0067] FIG. 22 illustrates a portion of the high acceleration
rotary actuator assembly 100, which is substantially as described
herein in association with FIG. 21. Operation and particular
components described herein are substantially the same and like
numbers have been used to illustrate the like components. The heat
conducting elements 300 may include a chamber 302 adapted to
receive a liquid cooling material. The heat conducting elements 300
having a liquid cooling chamber 302 provide for additional heat
extraction from the respective stator laminations 113 and winding
end turns 171 than heat conducting elements 300 alone or motors not
having heat conducting elements 300.
[0068] FIG. 23 illustrates a graphical representation of the motor
torque rating (X-axis) versus the torque to inertia ratio (Y-axis)
comparing servo motors currently commercially available with the
high acceleration rotary actuator assembly 100, 200 in accordance
with the assembly and associated advantages disclosed herein. The
graph illustrates the increase in torque to inertia ratio at a
motor torque rating of the high acceleration rotary actuator
assembly 100, 200 as compared with servo motors currently
commercially available.
[0069] There are several advantages to the high acceleration rotary
actuator assembly. The high acceleration rotary actuator assembly
has a low inertia rotor and shaft. The shaft has a lower inertia
than shafts or rotors of comparable motors, as the shaft has a
longer length and smaller diameter due to the tandem arrangement of
the phase motor elements. This provides for less inertia at a given
torque than traditional motors.
[0070] In addition, the approximate square shaped configuration of
the stator lamination provides advantages over standard circular
stator lamination. An approximate square shaped configuration
provides a greater amount of back iron in the stator lamination
than a standard circular stator lamination, allowing for an
increased amount of conductive material or winding to be wound
about each stator segment. Further, the square shaped configuration
of the stator lamination allows for a larger slot area, providing
for an increased amount of conductive material or winding to be
wound about each stator segment and placed in or through slots,
increasing the slot fill over a standard circular stator
lamination. The increased slot fill also advantageously reduces the
heat generation for a given torque and allows for a higher torque
and torque to inertia ratio. Further, slots may be provided toward
the corners of the stator lamination, providing for a reduction in
heat build-up in the stator lamination due to the improved heat
transfer or heat dissipation or cooling.
[0071] In addition, the segmented stator formed of segmented stator
elements provide for a winding with a single, contiguous wire. This
eliminates potential damage to the motor, for example by electrical
short, by excluding unreliable solder joints which are
traditionally used to connect windings. Further, the segmented
stator elements provide for an improved slot fill, as an increased
amount of winding may be placed in the slot, reducing the heat
generated in the winding for a given torque and resulting in a
higher torque value and an increase in torque to inertia ratio.
Further, by increasing slot fill, end turn waste is reduced.
[0072] In addition, electrically isolating each of the phase motor
elements provides for a high torque to inertia ratio. Motors which
tie the phase terminals together to a neutral point incur a
restriction in the realization of the optimum current waveform and
defeat the electrical isolation of the phases. Electrically
isolating each phase motor element may assist in the realization of
the optimum current waveform.
[0073] In addition, the amount of slot liner insulation will be
significantly less than conventional single stator, single rotor
multi-phase servo motors. Slot liner insulation is placed inside of
a slot to separate conductor wires and avoid a short. By increasing
the size of corner slots, more conductor wires may be placed in
each slot. By providing more room for conductor material in the
slots of each of the four poles, and accordingly more conductor
wires than insulation in a slot, heat is reduced.
[0074] In addition, the four pole arrangement lowers the electrical
frequency at high shaft and rotor speeds than conventional servo
motor designs incorporating six or more poles. Conventional servo
motors typically utilize six or more poles to reduce the back iron
and thus reduce the size of the motor. This results in reducing the
rated continuous torque at higher speeds because of higher iron
losses due to higher electrical frequencies by the increased
poles/pole pairs. The four pole square multi-phase tandem rotor
servo motor assembly does not reduce the rating of continuous
torque at high speeds as much as conventional motor designs because
of the lower frequency iron losses.
[0075] In addition, the high acceleration rotary actuator assembly
has a better speed range than conventional servo motors. At high
speeds, conventional servo motor drives will have to drive the
inductance. This requires extra voltage to drive the inductance
proportional to the electrical frequency. The four pole square
tandem servo motor assembly has a lower electrical frequency at
higher speeds than conventional servo motors incorporating six
poles or more. This advantageously enables the high acceleration
rotary actuator assembly to reach a greater maximum speed than
conventional servo motors and accordingly a greater speed
range.
[0076] Although various representative embodiments of this
invention have been described above with a certain degree of
particularity, those skilled in the art could make numerous
alterations to the disclosed embodiments without departing from the
spirit or scope of the inventive subject matter set forth in the
specification and claims. Joinder references (e.g., attached,
coupled, connected) are to be construed broadly and may include
intermediate members between a connection of elements and relative
movement between elements. As such, joinder references do not
necessarily infer that two elements are directly connected and in
fixed relation to each other. In some instances, in methodologies
directly or indirectly set forth herein, various steps and
operations are described in one possible order of operation, but
those skilled in the art will recognize that steps and operations
may be rearranged, replaced, or eliminated without necessarily
departing from the spirit and scope of the present invention. It is
intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative only and not limiting. Changes in detail or structure
may be made without departing from the spirit of the invention as
defined in the appended claims.
[0077] Although the present invention has been described with
reference to preferred embodiments, persons skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *