U.S. patent application number 12/104023 was filed with the patent office on 2008-08-14 for motor with integrated drive unit and shared cooling fan.
This patent application is currently assigned to RELIANCE ELECTRIC TECHNOLOGIES, LLC. Invention is credited to Michael J. Dudas, Jason A. Piper, Douglas H. Sudhoff.
Application Number | 20080191564 12/104023 |
Document ID | / |
Family ID | 37572701 |
Filed Date | 2008-08-14 |
United States Patent
Application |
20080191564 |
Kind Code |
A1 |
Piper; Jason A. ; et
al. |
August 14, 2008 |
Motor with Integrated Drive Unit and Shared Cooling Fan
Abstract
An integrated motor and drive assembly includes a motor, a fan,
and a drive unit. The motor is responsive to at least one drive
signal. The fan is axially aligned with the motor and operable to
generate a cooling flow. The drive unit is axially aligned with the
fan and operable to generate the drive signal. The cooling flow
traverses the motor and the drive unit.
Inventors: |
Piper; Jason A.; (Taylors,
SC) ; Dudas; Michael J.; (Greer, SC) ;
Sudhoff; Douglas H.; (Madison, IN) |
Correspondence
Address: |
THOMPSON COBURN, LLP
ONE US BANK PLAZA, SUITE 3500
ST LOUIS
MO
63101
US
|
Assignee: |
RELIANCE ELECTRIC TECHNOLOGIES,
LLC
Mayfield Heights
OH
|
Family ID: |
37572701 |
Appl. No.: |
12/104023 |
Filed: |
April 16, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11156827 |
Jun 20, 2005 |
7362017 |
|
|
12104023 |
|
|
|
|
Current U.S.
Class: |
310/63 ; 310/68R;
310/89 |
Current CPC
Class: |
H02K 11/33 20160101;
H02K 9/06 20130101 |
Class at
Publication: |
310/63 ;
310/68.R; 310/89 |
International
Class: |
H02K 9/06 20060101
H02K009/06 |
Claims
1. An assembly, comprising: a motor responsive to at least one
drive signal; a fan axially aligned with the motor and operable to
generate a cooling flow; and a drive unit axially aligned with the
fan and operable to generate the drive signal, the fan being
disposed between the motor and the drive unit, the cooling flow
traversing the motor and the drive unit.
2. The assembly of claim 1, wherein the motor includes a shaft, and
the fan is mounted to the shaft.
3. The assembly of claim 2, wherein the drive unit is axially
aligned with the shaft.
4. The assembly of claim 1, further comprising a drive enclosure
defining a drive cavity mounted to the motor, the drive unit being
disposed at least partially within the drive cavity.
5. The assembly of claim 4, further comprising at least one vent
defined in the drive enclosure communicating with the drive
cavity.
6. The assembly of claim 4, wherein the drive unit includes at
least one of a display and a control, and the drive enclosure
defines a window communicating with the drive cavity to expose at
least a portion of the drive unit proximate the one of the at least
one of the display and the control.
7. The assembly of claim 4, further comprising a fan shroud mounted
to the motor and defining a fan cavity enclosing at least a portion
of the fan and further defining at least one opening communicating
with the fan cavity, wherein the drive unit is mounted to the fan
shroud proximate the opening.
8. The assembly of claim 4, further comprising: a fan shroud
mounted to the motor and defining a fan cavity, the fan being at
least partially disposed within the fan cavity; and a mounting
bracket mounted to fan shroud, wherein the drive unit and the drive
enclosure are mounted to the mounting bracket, and the fan shroud
and mounting bracket each include at least one opening proximate
the drive unit, the openings communicating between the fan cavity
and the drive cavity.
9. The assembly of claim 8, wherein the mounting bracket includes a
body member and at least one tab extending from the body member,
the drive unit being mounted to the body member, and the drive
enclosure being mounted to the tab.
10. The assembly of claim 1, wherein the cooling flow comprises
intake flow upstream of the fan and exhaust flow downstream of the
fan, the intake flow traversing the drive unit and the exhaust flow
traversing the motor.
11. An assembly, comprising: a motor responsive to at least one
drive signal; a fan operable to generate a cooling flow including
an intake component and an exhaust component; and a drive unit
operable to generate the drive signal, wherein one of the intake
component and the exhaust component traverses the drive unit and
the other of the intake component and the exhaust component
traverses the motor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of application Ser. No.
11/156,827, filed Jun. 20, 2005, issued as U.S. Pat. No. 7,362,017
on Apr. 22, 2008.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to the art of
integrated motor and drive systems and, more particularly, to a
motor with an integrated drive unit and a shared cooling fan.
[0004] This section of this document is intended to introduce
various aspects of art that may be related to various aspects of
the present invention described and/or claimed below. This section
provides background information to facilitate a better
understanding of the various aspects of the present invention. It
should be understood that the statements in this section of this
document are to be read in this light, and not as admissions of
prior art.
[0005] Motors have broad application in industry, particularly when
large horsepower is needed. Typically, power in the form of AC
current provided by a utility is not suitable for end use in
consuming facilities. Thus, prior to end use, power delivered by a
utility is converted to a useable form. To this end, a typical
power "conditioning" configuration includes an AC-to-DC rectifier
that converts the utility AC power to DC across positive and
negative DC buses (i.e., across a DC link) and an inverter linked
to the DC link that converts the DC power back to three phase AC
power having an end-useable form (e.g., three phase, relatively
high frequency AC voltage). A controller controls the inverter in a
manner calculated to provide voltage waveforms required by the
consuming facility. The inverter includes a plurality of switches
that can be controlled to link and delink the positive and negative
DC buses to motor supply lines. The linking-delinking sequence
causes voltage pulses on the motor supply lines that together
define alternating voltage waveforms. When controlled correctly,
the waveforms cooperate to generate a rotating magnetic field
inside the motor stator core. In an induction motor, the magnetic
field induces a field in motor rotor windings. The rotor field is
attracted to the rotating stator field and thus the rotor rotates
within the stator core. In a permanent magnet motor, one or more
magnets on the rotor are attracted to the rotating magnetic field.
The rectifier, inverter, and control circuitry are commonly
referred to as a motor drive unit.
[0006] The use of integrated units where the motor drive is
integrated with the motor to create an "integrated motor and drive
system" has become more widely used. One advantage of such systems
is their compactness and ease of installation into a larger
industrial or other application, due largely to the close proximity
of the drive to the motor. Generally, the drive is disposed on the
motor or arranged in an integral housing with the motor.
[0007] One issue arising from the integrated motor and drive system
arrangement involves providing adequate cooling flow to dissipate
the collective heat generated by the motor and drive. Previous
techniques for providing cooling for an integrated motor and drive
involve providing independent cooling for the motor drive or
diverting a portion of the cooling flow from the motor fan to
impinge upon the motor drive or a heat sink associated with the
motor drive. These solutions add cost to the motor drive assembly
and sometimes fail to provide adequate cooling, as only a portion
of the cooling flow is employed.
[0008] Another disadvantage is that heat sinks applied to motor
drive components typically provide a cooling effect that is
substantially uniform over its surface area. This is due to the
even, or regular, distribution of the heat transfer fins on the
face of the heat sink. This design limitation largely ignores the
reality in motor drives that certain power and other electronic
components generate large amounts of heat, while other devices may
generate only small amounts. Thus, a traditional heat sink requires
that either the power components be evenly distributed over the
heat sink surface with regard to their power generating
capabilities, or that a large enough heat sink is used to
compensate for "hot spots" created by the physical arrangement of
power components to provide for adequate cooling of the largest
expected localized areas of heat generation.
BRIEF SUMMARY OF THE INVENTION
[0009] The present inventors have recognized that a motor and drive
assembly may be implemented where a motor is axially aligned with a
motor drive unit to allow cooling flow generated by a fan
associated with the motor to cool both the motor and the motor
drive unit.
[0010] One aspect of the present invention is seen in an assembly
including a motor, a fan, and a drive unit. The motor is responsive
to at least one drive signal. The fan is axially aligned with the
motor and operable to generate a cooling flow. The drive unit is
axially aligned with the fan and operable to generate the drive
signal. The cooling flow traverses the motor and the drive
unit.
[0011] Another aspect of the present invention is seen in an
assembly including a motor, a fan, a fan shroud, a drive unit, and
a drive enclosure. The motor is responsive to at least one drive
signal. The fan is axially aligned with the motor and operable to
generate a cooling flow. At least a portion of the cooling flow
traverses the motor. The fan shroud is mounted to the motor and
defines a fan cavity enclosing at least a portion of the fan and at
least one opening communicating with the fan cavity. The drive unit
is disposed within the cooling flow and operable to generate the
drive signal. The drive enclosure is mounted to the fan shroud and
defines a drive cavity enclosing at least a portion of the drive
unit and at least one vent communicating with the drive cavity.
[0012] Yet another aspect of the present invention is seen in an
assembly including a motor, a fan, and a drive unit. The motor is
responsive to at least one drive signal. The fan is operable to
generate a cooling flow including an intake component and an
exhaust component. The drive unit is operable to generate the drive
signal. One of the intake component and the exhaust component
traverses the drive unit and the other of the intake component and
the exhaust component traverses the motor.
[0013] These and other objects, advantages and aspects of the
invention will become apparent from the following description. The
particular objects and advantages described herein may apply to
only some embodiments falling within the claims and thus do not
define the scope of the invention. In the description, reference is
made to the accompanying drawings which form a part hereof, and in
which there is shown a preferred embodiment of the invention. Such
embodiment does not necessarily represent the full scope of the
invention and reference is made, therefore, to the claims herein
for interpreting the scope of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] The invention will hereafter be described with reference to
the accompanying drawings, wherein like reference numerals denote
like elements, and:
[0015] FIG. 1 is an exploded isometric view of an integrated motor
and drive assembly in accordance with one embodiment of the present
invention;
[0016] FIG. 2 is an exploded side view of the motor and drive
assembly of FIG. 1; and
[0017] FIG. 3 is a side cutaway view of the motor and drive
assembly of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0018] One or more specific embodiments of the present invention
will be described below. It is specifically intended that the
present invention not be limited to the embodiments and
illustrations contained herein, but include modified forms of those
embodiments including portions of the embodiments and combinations
of elements of different embodiments as come within the scope of
the following claims. It should be appreciated that in the
development of any such actual implementation, as in any
engineering or design project, numerous implementation-specific
decisions must be made to achieve the developers' specific goals,
such as compliance with system-related and business related
constraints, which may vary from one implementation to another.
Moreover, it should be appreciated that such a development effort
might be complex and time consuming, but would nevertheless be a
routine undertaking of design, fabrication, and manufacture for
those of ordinary skill having the benefit of this disclosure.
Nothing in this application is considered critical or essential to
the present invention unless explicitly indicated as being
"critical" or "essential."
[0019] Referring now to the drawings wherein like reference numbers
correspond to similar components throughout the several views and,
specifically, referring to FIGS. 1, 2 and 3, the present invention
shall be described in the context of a motor and drive assembly 10.
The motor and drive assembly 10 includes an electric motor 20, fan
shroud 30, mounting bracket 40, drive unit 50, and drive enclosure
60. As shown in FIG. 3, the electric motor 20 has a generally
cylindrical housing 70 surrounding a motor core 80. The motor core
80 converts electrical energy to mechanical energy to drive
external devices coupled to the motor 20. The motor core 80
includes a stator 90, a rotor 100, and any other wiring and
circuitry (not shown) for driving the motor 20. The rotor 100 is
coupled to a shaft 110 extending through a central longitudinal
axis of the motor 20.
[0020] During operation of the motor 20, electrical current is
provided to the windings of the stator 90 by the drive unit 50,
which generates a magnetic field that induces a current in the
windings of the rotor 100. The induced current in the windings of
the rotor 100 also generates a magnetic field in an opposite
direction with respect to the magnetic field generated in the
windings of the stator 90. The oppositely directed magnetic fields
interact and cause the rotor 100 to rotate, thus, rotating the
shaft 110. The shaft 110 is supported by a first bearing assembly
120 disposed at a load end 130 of the shaft 110, and a second
bearing assembly 140 disposed at a fan drive end 150 of the shaft
110. A fan 160 is mounted to the shaft 110 at its fan drive end 150
for providing cooling flow to the motor 20 and the drive unit 50
during its operation. The fan shroud 30 defines a fan cavity 165
enclosing the fan 160 and affecting the direction of the cooling
flow.
[0021] Heat is generated by the motor core 80 during operation of
the motor 20. The heat generated by the motor core 80 heats the air
inside the housing 70. This heated air, if not dissipated, has a
deleterious effect on the efficient operation and life of the
bearing assemblies 120, 140 and insulation. Therefore, the fan 160
is provided to cool the motor 20. However, because the motor and
drive assembly 10 includes an integrated drive unit 50, additional
heat is also generated by the electronic circuitry used to
implement the functions of the drive unit 50. The drive unit 50 is
mounted in axial alignment with the motor 20 and fan 160 such that
cooling flow generated by the fan 160 also flows over the drive
unit 50, thereby removing additional heat generated by the drive
unit 50. As described in greater detail below, the drive enclosure
60 constrains the cooling flow to ensure that it is provided both
to the motor 20 and the drive unit 50.
[0022] In general, the drive unit 50 includes circuitry for
generating drive signals for controlling the motor 20. The drive
unit 50 includes rectifying circuitry that receives 1 or 3-phase
power from an external power supply and converts the AC power to
DC. Inverter circuitry in the drive unit 50 is positioned between
positive and negative DC buses of the rectifier to generate the
signals for driving the motor 20. The inverter circuitry includes a
plurality of switching devices (e.g., transistors) that are
positioned between the positive and negative DC buses and drive
leads (not shown) coupled to the motor 20, such that by opening and
closing specific combinations of the inverter switches, positive
and negative DC voltage pulses are generated on each of drive
leads. By opening and closing the inverter switches in specific
sequences, AC voltages having controllable amplitudes and
frequencies can be generated on each of the drive leads coupled to
the motor 20.
[0023] As seen in FIGS. 1 and 2, the drive unit 50 includes a
display 170 and one or more controls 180 for configuring the drive
unit 50. For example, various operating parameters, such as speed,
direction of rotation, operating state (i.e., on or off), etc., of
the motor 20 may be set using the control 180. In some embodiments,
the drive unit 50 may include an external data port (not shown)
through which the drive unit 50 may be programmed or configured
prior to installation. The particular configuration technique used
to program the drive unit 50 is not material to the practice of the
present invention, and may vary depending on the particular
implementation.
[0024] Still referring the FIGS. 1 and 2, the assembly of the motor
and drive assembly 10 is now described in greater detail. The fan
shroud 30 is mounted to the motor 20 to enclose the fan 160 by
bolts 190 that extend through holes 195 in the fan shroud 30 to
interface with threaded holes 200 defined in the housing 70. The
mounting bracket 40 mounts to the fan shroud 30 via bolts 210 that
pass through holes 215 to interface with threaded holes 220 defined
in the fan shroud 30. The drive unit 50 mounts to the mounting
bracket 40 via bolts 230 that interface with threaded holes 240
defined in the mounting bracket 40. The mounting bracket 40
includes a generally ring-shaped body 245 and tabs 250 extending
perpendicularly with respect to the body 245. The tabs 250 include
threaded holes 260 aligned with corresponding holes 270 defined in
the drive enclosure 60. Bolts 280 pass through the holes 270 in the
drive enclosure 60 and interface with the threaded holes 260
defined in the tabs 250 to mount the drive enclosure 60. A first
lead opening 285 defined in the fan shroud 30 and a second,
corresponding lead opening 290 defined in the mounting bracket 40
allow electrical leads (not shown) from the drive unit 50 to pass
through the fan shroud 30 and mounting bracket 40 to be connected
to the motor 20.
[0025] The mounting configuration shown in FIGS. 1 and 2 is
provided for illustrative purposes. Other mounting configurations
may be used. For example, the drive unit 50 and/or the drive
enclosure 60 may mount directly to the fan shroud 30 without an
interposing mounting bracket.
[0026] In general, the fan shroud 30 and drive enclosure 60
cooperate to define the path for cooling air flow generated by the
fan 160. In the illustrated embodiment, the fan 160 is
bidirectional, such that regardless of the direction of rotation of
the motor 20, cooling air flows in the direction provided by the
arrow 300 shown in FIG. 3.
[0027] As seen in FIGS. 2 and 3, the drive enclosure 60 includes
vents 310 and a window 320. The window 320 is generally provided to
allow access to the drive enclosure 60 by an operator, however, in
an embodiment where the drive unit 50 is preconfigured, the window
320 may be omitted. Also, in some embodiments, a gasket (not shown)
corresponding to the geometry of the window 320 may be provided to
provide a seal between the drive unit 50 and the drive enclosure 60
to reduce the likelihood that foreign material is drawn into the
drive enclosure 60.
[0028] Intake air for the fan 160 enters the drive enclosure 60
through the vents 310. The drive enclosure 60 defines a drive
cavity 330 surrounding the drive unit 50. Heat generated by the
drive unit 50 heats the air present in the drive cavity 330.
Because the intake air for the fan 160 is drawn in through the
vents 310 and into the drive cavity 330, the heat from the drive
unit 50 is dissipated by the intake component of the cooling flow.
In the illustrated embodiment, the vents 310 are defined by
openings in the drive enclosure 60 that spell the word "MASTER."
However, other vent geometries may be used.
[0029] The fan shroud 30 includes one or more openings 340 to allow
the passage of intake cooling flow through the fan shroud 30. The
mounting bracket 40 includes a central opening 350 corresponding to
the opening 340 defined in the fan shroud 30. Hence, intake air
enters the drive enclosure 60 through the vents 310, traverses the
drive unit 50, and passes through the opening 350 defined in the
mounting bracket 40 and the opening 340 defined in the fan shroud
30 to reach the fan 160. Again, this direction of flow is indicated
by the arrow 300 shown in FIG. 3. Hence, the intake component of
the cooling flow cools the drive unit 50 prior to reaching the fan
160. The exhaust portion of the cooling flow generated by the fan
160 passes through the motor core 80 and exits through ports (not
shown) defined in the housing 70 proximate the load end 130 of the
shaft 110, thereby cooling the motor core 80.
[0030] The motor and drive assembly 10 of the present invention
provides cooling flow for the drive unit 50 without necessitating
auxiliary cooling, additional heat sinks, or modifications to the
motor 20 or housing 70, thereby reducing the cost and complexity of
the motor and drive assembly 10. The cooling flow generated by the
fan includes an intake component that cools the drive unit 50 and
an exhaust component that cools the motor 20.
[0031] The particular embodiments disclosed above are illustrative
only, as the invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. Furthermore, no limitations
are intended to the details of construction or design herein shown,
other than as described in the claims below. It is therefore
evident that the particular embodiments disclosed above may be
altered or modified and all such variations are considered within
the scope and spirit of the invention. Accordingly, the protection
sought herein is as set forth in the claims below.
* * * * *