U.S. patent application number 11/069199 was filed with the patent office on 2005-07-07 for resin application system for dynamo-electric machine components.
This patent application is currently assigned to Axis USA, Inc.. Invention is credited to Becherucci, Raffaele, Stratico, Gianfranco.
Application Number | 20050144778 11/069199 |
Document ID | / |
Family ID | 23021486 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050144778 |
Kind Code |
A1 |
Becherucci, Raffaele ; et
al. |
July 7, 2005 |
Resin application system for dynamo-electric machine components
Abstract
A resin application station has processing units for heating
dynamo-electric machine components. In one or more of the
processing units batches of components are placed in fixtures on
vertically rotating support plates. The vertically rotating support
plates are mounted in cabinets. Heated air is circulated in the
cabinets to control the ambient temperature. The components travel
through regions of the controlled temperature ambient as the
support plates rotate and are heated to process temperatures.
Intermittent rotation of a support plate in a unit allows loading
and unloading of an individual component from the unit while the
support plate is stationary. The support plate rotations in all the
units are synchronized to increase the station throughput
Inventors: |
Becherucci, Raffaele;
(Scandicci, IT) ; Stratico, Gianfranco; (Siena,
IT) |
Correspondence
Address: |
FISH & NEAVE IP GROUP
ROPES & GRAY LLP
1251 AVENUE OF THE AMERICAS FL C3
NEW YORK
NY
10020-1105
US
|
Assignee: |
Axis USA, Inc.
|
Family ID: |
23021486 |
Appl. No.: |
11/069199 |
Filed: |
February 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11069199 |
Feb 28, 2005 |
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10073400 |
Feb 11, 2002 |
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6878203 |
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60268103 |
Feb 12, 2001 |
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Current U.S.
Class: |
29/732 ; 29/596;
29/598; 310/418 |
Current CPC
Class: |
B05D 1/18 20130101; B05D
3/0254 20130101; Y10T 29/49012 20150115; Y10T 29/53143 20150115;
H02K 15/12 20130101; B05D 3/0218 20130101; B05D 3/0413 20130101;
B05D 1/002 20130101; Y10T 29/49009 20150115 |
Class at
Publication: |
029/732 ;
029/598; 310/258; 029/596 |
International
Class: |
H02K 001/12 |
Claims
1-26. (canceled)
27. A method for applying resin to dynamo-electrical machine
components, comprising: loading said components in first holding
fixtures, wherein said first holding fixtures are disposed in an
annular region on the face of a first vertical support plate
rotatably mounted in a preheating cabinet; flowing heated air
through said cabinet to provide a temperature controlled ambient
therein; rotating said first vertical support plate such that said
loaded components travel through said controlled temperature
controlled ambient and are heated to a predetermined temperature;
unloading said heated components from said preheating cabinet;
transferring said unloaded heated components to a resin application
unit, wherein said resin application unit comprises means for
applying a quantity of resin to said components; and applying resin
to said transferred components in said resin application unit.
28. The method of claim 27 wherein said rotating said first
vertical support plate further comprises rotating said first
vertical plate intermittently with first periods of rotation
alternating with first periods of pause such that that a said first
holding fixture disposed on said first vertical support plate is
aligned with a first loading position, wherein said unloading said
heated components from said preheating cabinet further comprises
unloading a said heated component from said first holding fixture
aligned with said first loading position during a said first period
of pause, and wherein loading said components in first holding
fixtures further comprises loading a said component in said first
holding fixture aligned with said first loading position from which
said heated component has been unloaded during same said first
period of pause.
29. The method of claim 28 wherein transferring said unloaded
heated components to a resin application unit further comprises:
reloading said unloaded heated components in an empty second
holding fixture, wherein a plurality of said second holding
fixtures are disposed in an annular region on the face of a second
vertical support plate rotatably mounted in said resin application
unit, and wherein said reloading occurs while said second vertical
support plate is stationary and said empty second holding fixture
is aligned with a second loading position; and wherein applying
resin to said transferred components in said resin application unit
further comprises: intermittently rotating said second vertical
support plate with second periods of rotation alternating with
second periods of pause to advance said reloaded heated component
away from said second loading position through said resin
application unit; and using said means for applying a quantity of
resin during a second period of pause after said advanced component
has moved away from said second loading position to apply resin
said advanced component.
30. The method of claim 27 further comprising: heat curing the
resin applied to said components.
31. The method of claim 30 wherein heat curing the resin applied to
said components further comprises: transferring said components
with resin applied to them out of said resin application unit;
loading said components in third holding fixtures, wherein said
third holding fixtures are disposed in an annular region on the
face of a third vertical support plate rotatably mounted in a
resin-curing cabinet; flowing heated air through said resin-curing
cabinet to provide a temperature controlled ambient therein; and
rotating said third vertical support plate such that said loaded
components travel through said controlled ambient to heat said
applied resin.
Description
[0001] This application claims the benefit of U.S. provisional
application No. 60/268,103 filed Feb. 12, 2001.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to improved solutions for
conveying and processing dynamo-electric machine components (e.g.,
armatures or stators for electric motors, generators, or
alternators) through resin application process steps.
[0003] Resin application steps are common in the manufacturing of
dynamo-electric machine components. The dynamo-electric machine
components such as armatures include insulated wire coils wound on
ferromagnetic cores. Electric current passes through the wire coils
in the operation of the dynamo-electric machine in which the
component is used. For optimal performance of the dynamo, the
dynamo-electric machine components' wire coils may be subject to
tight dimensional tolerances. However, the wires in the coils,
which are mechanically wound, are susceptible to loosening by
vibration or heat during further manufacturing or assembly steps.
Operation of the dynamo-electric machine itself may also cause
vibrations and heat, which tend to loosen the wire coils.
Electrical current, which passes through the wire coils, also may
generate electro-mechanical forces that tend to loosen or deform
the wire coil shape. To avoid distortion of the wire coil
dimensions due to these or other causes, the wires in a coil are
customarily coated and encased in an adhesive bonding material
matrix such as a resin. The resin mechanically stabilizes the wire
coil by binding the wires in the coil together, and thereby
preventing relative movement of the wires. Additionally, the resin
coating provides a heat conduction path to dissipate heat generated
in the wires. The resin coating also protects the wire insulation
from abrasion during further steps of the manufacturing process and
during the operation of the dynamo-electric machine.
[0004] The resin coating and bonding process steps are carried out
in the dynamo-electric manufacturing process using resin
application stations. Resin application stations may, for example,
include resin impregnation machines in which liquid dispensers
trickle liquid resins on to the wire coils. The dispensed liquid
resin impregnates the wire coils by filling up interwire spaces,
for example, by capillary action. Alternatively, resin impregnation
machines may dip the components in liquid baths to coat the wires
with the resin. A resin application station usually involves
additional machines for preparing the dynamo-electric machine
components for resin impregnation, and for curing or hardening the
impregnated liquid resin. These additional machines may include
pre-heating units or curing units for regulating the temperature of
the components during the resin application process. Resin
application stations are integrated into manufacturing assembly
lines by the use of suitable component holding devices and conveyor
apparatus. The conveyor apparatus may carry components in pallets
on belts running between the resin application stations and other
processing stations in the assembly line.
[0005] Resin impregnation machines and ovens that are used in resin
application stations, particular dispositions of resin application
stations along an assembly line, transport routes by which the
component-carrying pallets reach the stations, and sequences by
which the pallets reach the stations have been described, for
example, in Santandrea et al. U.S. Pat. No. 4,984,353, Cardini et
al. U.S. Pat. No. 5,443,643, Cardini et al. U.S. Pat. No.
5,569,439, Faraoni et al. U.S. Pat. No. 5,401,531, Galassi et al.
U.S. Pat. No. 5,919,308, Galassi et al. U.S. Pat. No. 6,024,795,
and Becherucci et al. U.S. patent application Ser. No. 09/409,038,
Becherucci et al. U.S. Pat. No. 6,226,857, and Sabatino et al.
European Patent 0,757,425, all of which are hereby incorporated by
reference herein in their entireties.
[0006] The uniformity and reproducibility dynamo-electric machine
manufacturing processes are sensitive to variations in processing
conditions. For example, in resin application processes, for
example, resin viscosity and consequently resin settling may be
affected by variations or fluctuations in temperature.
[0007] Consideration is now being given generally to ways of
providing solutions for improving uniformity and reproducibility in
dynamo-electric machine component manufacture. Attention is
directed to resin application stations including resin impregnation
machines, heating units, and curing units, with a view to improve
the resin coating process and to improve the overall efficiency of
dynamo-electric machine component manufacturing.
SUMMARY OF THE INVENTION
[0008] In accordance with the principles of the invention, resin
application stations for impregnating dynamo-electric machine
component wire coils with liquid resin in order to coat and bond
the wires in a resinous matrix are provided.
[0009] The resin application stations include at least a preheating
unit, a resin impregnation unit, and a resin-curing unit. The units
may be used to carry out similarly named process steps in the
manufacture of dynamo-electric machine components. Each unit has a
cabinet or enclosure inside which the process step is carried out.
Support members or fixtures are provided in each of these units to
hold individual component subassemblies in proper orientation for
processing.
[0010] Each of these three units includes a vertical rotating
support structure. This support is mounted inside the unit cabinet
so that the support structure can rotate about a horizontal axis.
Large numbers of support fixtures may be disposed on a support
structure. Thus, these units may have large load capacities for
simultaneously processing several subassemblies.
[0011] The ambient temperature in the unit cabinets is controlled
to ensure uniformity and consistent processing conditions. In
particular, forced air heating techniques are used to provide a
heated ambient for uniformly maintaining large numbers of
subassemblies at the same predetermined temperature. The
predetermined temperatures may be those that are suitable for the
resin application processes. The air flow or circulation paths in
the unit cabinets are designed to increase uniformity in the
heating of subassemblies.
[0012] The resin application station itself is configured to
integrate the operation of the three units used in the resin
application processes. The resin application station is also
configured so that it may be integrated in an assembly line, and
for use with conventional assembly line transfer tools and control
units.
[0013] By scheduling the processing and transfer of subassemblies
through the station units using suitable control unit programming,
the workflow through the station may be maximized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Further features of the invention, its nature, and various
advantages will be more apparent from the following detailed
description of the preferred embodiments and the accompanying
drawings, wherein like reference characters represent like elements
throughout, and in which:
[0015] FIG. 1 is a side elevational view of a resin application
station with a cover removed to show a preheating unit, a resin
impregnation unit, and a curing unit in accordance with the
principles of this invention.
[0016] FIG. 2 is a sectional view of the preheating unit of FIG. 1,
as seen from directions 2-2 in FIG. 1.
[0017] FIG. 2a is an enlarged view of a portion of the preheating
unit of FIG. 2, showing a support member carrying an armature.
[0018] FIG. 2b is a sectional view of the support member of FIG.
2a, as seen from directions 2b-2b in FIG. 2a.
[0019] FIG. 3 is an enlarged view of the preheating unit shown in
FIG. 1.
[0020] FIG. 4 is a sectional view of the resin impregnation unit of
FIG. 1, as seen from directions 4-4 in FIG. 1.
[0021] FIG. 5 is an enlarged view of the resin impregnation unit
shown in FIG. 1.
[0022] FIG. 6 is a sectional view of the curing unit of FIG. 1, as
seen from directions 6-6 of FIG. 1.
[0023] FIG. 7 is schematic representation of the resin application
station of FIG. 1, showing the various routes that can be taken by
machine components that are processed through the resin application
station. FIG. 7 additionally shows a station control unit, and
gripper units for holding and moving the machine components through
the resin application station. However, for clarity, several parts
of the preheating unit, the resin impregnation unit, and the curing
unit that were shown in FIG. 1 are omitted from FIG. 7.
[0024] FIG. 7a is an enlarged view of a gripper unit shown in FIG.
7.
[0025] FIG. 8 is a schematic representation listing control steps
performed by the control unit of FIG. 7 for synchronizing the
operation of the preheating unit, the resin impregnation unit, and
the curing unit.
[0026] In several of the accompanying drawings, which show
sectional views, hatching or shading of various sectional elements
have been omitted for clarity. It will be understood that this
omission of hatching or shading in the drawings is for the purpose
of clarity in illustration only.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] The present disclosure provides solutions for improving
uniformity and reproducibility in dynamo-electric machine component
manufacture. A disclosed solution concerns resin application
stations for applying dynamo-electric machine components with
resin. Integrated resin application stations in which the
dynamo-electric machine component subassemblies can be prepared for
resin application, and in which resin can be applied and cured are
disclosed.
[0028] Other aspects of the present invention relate to improved
solutions for conveying the component subassemblies through the
resin application stations and for integration of the workflow
through the workstation and the assembly line in which the
workstation is deployed.
[0029] In accordance with the present invention, a resin
application workstation is configured to include a preheating unit,
a resin application unit, and a resin curing unit. The preheating,
resin application, and curing units are placed adjacent to each
other in sequence matching the steps in the manufacturing process.
Each unit has a designed capacity sufficient to batch process a
suitable number of the subassemblies substantially simultaneously.
The workstation is configured for use in a manufacturing assembly
line. Traveling gripper units are provided for transferring
subassemblies between assembly line conveyor apparatus and the
resin application workstation. The gripper units are also used to
transfer subassemblies between the various units of the resin
application workstation.
[0030] All three units in the resin application workstation include
rotating support plates. Each support plate is mounted vertically
and enclosed in a walled enclosure or compartment. The support
plates in the three units can rotate about horizontal axles.
Electrical motors or other drive means such as belt drives coupled
to the horizontal axles may power the support plate rotation. The
vertical support plates have support fixtures to hold the
subassemblies in a substantially horizontal orientation during
processing.
[0031] The preheating unit and the resin-curing unit heat the
component subassemblies to suitable temperatures in preparation for
resin application and for resin curing, respectively. The curing
unit may include a subcompartment or section for cooling the
processed subassemblies after resin curing. Any suitable heat
sources may be used in the preheating and curing units to heat and
raise the temperature of the subassemblies. The suitable heat
sources may, for example, be resistive heater elements or infrared
lamps mounted within the unit compartments. In one embodiment,
forced air heating techniques are used to heat the component
subassemblies in the units. Forced air convection heating may
provide more efficient and uniform heating of a large number of
subassemblies. Forced air heating may also be economically
advantageous.
[0032] In order that the invention herein described can be fully
understood, the subsequent description is set forth in the context
of resin application in the manufacture of armatures. It will,
however, be understood that the invention is equally applicable to
other types of dynamo-electric machine components having wound wire
coils such as stators, etc.
[0033] An embodiment of the present invention is described herein
with reference to station 1000 and to the work pieces illustrated
in FIGS. 1-7. Armature subassemblies 13 (see, e.g., FIG. 2a) are
used herein as illustrative work pieces. Armature subassemblies 13
have stack portions or ferromagnetic core portions around which
wire coils are wound at winding machines (not shown) earlier in the
assembly line. Portions of the wire coil (portions 13") extend out
of the ferromagnetic core portions. Armature subassemblies 13 have
axial shafts 13S which protrude from the central ferromagnetic core
portions along axis 13'. The axial shafts 13S have extreme ends
13e.
[0034] FIG. 1 shows resin application station 1000, which includes
preheating unit 1100, resin impregnation unit 1200 adjacent to unit
1100, and resin curing unit 1300 adjacent to unit 1200. Preheating
unit 1100 is designed to heat subassemblies 13 by forced air
heating to a predetermined temperature. The predetermined
temperature may be chosen with consideration to the viscous
properties of the subsequently applied resin (in unit 1200). The
predetermined temperature may be chosen so that the applied resin
has suitable viscosity or other flow characteristics at the raised
temperature of wire coils 13" for effective impregnation or
saturation of the wire coils 13". Resin impregnation unit 1200 may
use conventional tooling for applying resin to the pre-heated wire
coils 13". The tooling may include, for example, a series of liquid
dispenser units (e.g., dispenser units DU in FIG. 5) for dropping
or trickling controlled amounts of liquid resin on the pre-heated
wire coils 13". The liquid resin may be fed to the liquid
dispensers from pump and storage devices, which may, for example,
be similar to those described in Santandrea et al. U.S. Pat. No.
4,984,353, Cardini et al. U.S. Pat. No. 5,443,643, Cardini et al.
U.S. Pat. No. 5,569,439, Faraoni et al. U.S. Pat. No. 5,401,531,
Galassi et al. U.S. Pat. No. 5,919,308, Galassi et al. U.S. Pat.
No. 6,024,795, Becherucci et al. U.S. patent application Ser. No.
09/409,038, Becherucci et al. U.S. Pat. No. 6,226,857, and Sabatino
et al. European Patent 0,757,425. Resin curing unit 1300 is
designed to heat subassemblies 13, by forced air heating, to
suitable temperatures for hardening or curing the resin saturating
wire coils 13" that was applied in impregnation unit 1200.
[0035] All three units 1100, 1200, and 1300 may have drum-like
cylindrical structures with front plates covering the front
cylinder openings (see, e.g., front plate 21' in FIG. 2, front
plate 35 in FIG. 4, and front plate 45 in FIG. 6). All three units
1100-1300 are mounted in an enclosure, for example, cabinet 101.
One or more sides of cabinet 101 may be walls or panels 102
attached to a suitable chassis or frame 101c (see, e.g., FIG. 2).
Chassis 101c may be supported off an assembly line floor by support
legs 103. Support legs 103 may include suitable conventional
anti-vibration and leveling mechanisms (not shown). Assembly line
conveyor apparatus 73 may be used to move unprocessed armatures for
processing by workstation 1000 to a suitable loading position.
Loading position T1 is shown, for example, at the left end of
cabinet 101. Similarly, processed armatures may be moved away from
workstation 1000 from a suitable unloading position. Unloading
position T2 is shown, for example, at the right end of cabinet 101.
Cabinet 101 may be sufficiently large to allow ample workspace
around units 1100-1300 for machine or worker access to service
units 1100-1300. For example, the space around units 1100-1300
(see, e.g., space WS in FIG. 2) may be used to deploy transfer
tools (e.g., gripper units 70 deployed in front space 70' FIG. 7)
for transferring subassemblies to and from units 1100, 1200, and
1300.
[0036] FIG. 1 shows station 1000 with front panel 102 and front
plates of all three units 1100-1300 removed to expose interior
portions of units 1100-1300 for viewing.
[0037] Units 1100-1300 include vertical support plates 10, 30 and
39, respectively. Vertical support plates 10, 30 and 39 are
circular in shape and are mechanically mounted to rotate about
their axes AX, AX1, and AX2, respectively. In preheating unit 1100
numerous support fixtures 11, which hold subassemblies 13 during
processing, are disposed on vertical support plate 10 in concentric
circular patterns within annular compartment 24. The circular
patterns may be chosen with design considerations to factors such
as the desired processing batch size and heating efficiency. The
central region or inner compartment 24' formed by the annulus of
compartment 24 is free of support fixtures 11. Similarly, in resin
curing unit 1300 numerous support fixtures 41, which hold
subassemblies 13 during the curing process, are disposed on
vertical support plate 39 in concentric circular patterns within
outer compartment 40. Outer Compartment 40 may optionally have an
annular shape with its central core forming an inner compartment
42. Inner compartment 42 may be used as a cooling station to cool
subassemblies 13 that previously have been heated for resin curing
in outer compartment 40. Inner compartment 42 may include
additional vertical support plate 44. Vertical support plate 44 is
mounted to rotate about the same axis (AX2) as vertical support
plate 39. Vertical support plate 44 may be independent or,
alternatively, an integral structural portion of vertical support
plate 39. Support fixtures 43, which hold the armatures 13 during
the cooling process, are disposed on vertical support plate 44 in a
circular pattern. In resin impregnation unit 1200, vertical support
plate 30 is similarly provided with support fixtures 31 for holding
subassemblies 13 during the resin impregnation process.
[0038] The front plates of units 1100-1300 (i.e. front plate 21'
FIG. 2, front plate 35 FIG. 4, and front plate 45 FIG. 6) each have
windows or apertures in them, through which subassemblies 13 may be
loaded into or unloaded from units 1100-1300. Even though the front
plates are not shown in FIG. 1, the contours of apertures 25, 36,
and 46 corresponding to units 1100, 1200 and 1300, respectively,
are schematically represented in FIG. 1 by dashed lines.
[0039] Further details of the construction of preheating unit 1100
are shown in FIG. 2. FIG. 2. shows a sectional view of preheating
unit 1100, as seen from directions 2-2 of FIG. 1. Vertical support
plate 10 consists of a vertical round table-like structure.
Vertical support plate 10 is mounted on shaft 12' of shaft and
bearing unit 12 so that it can freely rotate about horizontal axis
AX. Suitable mechanical means, for example, flange 10', may be used
to mount vertical support plate 10 on an end face of shaft 12'. A
motor drive (not shown) or other suitable means may be used to turn
shaft 12' about axis AX. The drive means used to turn shaft 12' may
be electrically connected by suitable links (not shown) to
workstation 100's control unit 72 (see FIG. 7) so that the drive
means operates under the supervision of control unit 72. The
rotation of shaft 12' may be controlled by control unit 72 to meet,
for example, unit 1100's process criteria or workflow
conditions.
[0040] FIG. 2a shows an enlarged portion of vertical support plate
10 to further illustrate details of the disposition of a support
fixture 11 carrying an armature subassembly 13. FIG. 2b shows
support fixture 11 as viewed from directions 2b-2b of FIG. 2a.
Support fixture 11 may have an open cage-like cylindrical structure
suitable for holding a subassembly 13 in position for processing.
Disk 15 forms the base of the cylindrical structure. A number of
horizontal ribs 14 extend outward from disk 15 along the sides of
the cylindrical structure to form the open cage-like structure (to
the left in FIG. 2a). In operations loading or placing subassembly
13 in support fixture 11 (e.g., using gripper unit 70 in FIG. 7),
the longitudinal position of subassembly 13 in support member 11
may be referenced by the abutment of subassembly shaft's distal end
13e against disk 15. Disk 15 is mounted or attached to shaft
extension 17 (extending to the right in FIG. 2a). Bearing unit 18
is disposed within vertical support plate 10. Shaft extension 17
may be mounted in bearing unit 18 so that it is free to idle as
bearing unit 18 revolves about central axis AX. Bolt 18' or other
suitable mechanical means may be used to lock shaft extension 17 in
bearing unit 18.
[0041] FIG. 2b shows, for example, three horizontal ribs 14, which
are attached at equal angular spacings along the circumference of
disk 15. Annular ring 16 at the open proximal end (left end of FIG.
2a) of the cylindrical structure retains ribs 14 in position to
complete the open cage-like cylindrical structure of support
fixture 11. The open annulus of ring 16 is sufficiently large to
allow passage of subassembly 13 therethrough. Armature 13 may be
placed in or removed from support fixture 11 by movements in
direction 13b and 13a, respectively (see FIG. 2a). Ribs 14 provide
supporting surfaces to hold subassembly 13 in place. The diameter
of the cylindrical structure of support fixture 11 is chosen so
that the supporting surfaces of ribs 14 engage the stack portion of
the armature. Further, the diameter is also chosen with
consideration to provide adequate clearance for the free passage of
subassembly 13 in and out of support fixture 11. The chosen
diameter may consequently be sufficiently large so that, in
operation, subassembly 13's stack portion rests on and is supported
by only the two lower most ribs 14 (FIG. 2b). Third upper rib 14,
even if not in contact with subassembly 13's stack portion,
advantageously serves to constrain subassembly 13 from toppling due
to any accidental movement, for example, during equipment or
machine malfunctions.
[0042] When subassembly 13 rests on and is supported by the two
lower most ribs 14, shaft 13S is eccentrically aligned downward
with respect to horizontal axis 17' of shaft 17 (e.g., vertically
below axis 17' in FIG. 2a). This downward alignment causes the
center of gravity of the support fixture 11 (when loaded with
subassembly 13) to be vertically lower than axis 17'. This lowering
of the center of gravity may prevent rotation of subassembly 13
about its axis 13' as vertical support plate 10 rotates about its
axis AX (causing bearing unit 18 to revolve about AX.)
[0043] Further details of the construction of preheating unit 1100
are described below with reference to FIG. 2 in conjunction with
FIG. 3. FIG. 3 is an enlarged view of preheating unit 1100 shown in
FIG. 1. Vertical support plate 10 is surrounded by outer cylinder
20, back wall 21, and front plate 21'. Outer cylinder 20 is
supported on upstanding frame structure 22. Frame structure 22 may
be suitably attached to, or alternatively be an integral part of
cabinet 101's chassis 101c. Outer cylinder 20 is open at both ends.
Back open end of cylinder 20 is closed by back wall 21. Shaft and
bearing unit 12 (to which vertical support plate 10 is attached
using flange 10') is centrally mounted on back wall 21. Front open
end of cylinder 20 is closed off by front plate 21'. Inner cylinder
23 has an open front end and a closed back end. Front plate 21'
closes inner cylinder 23's open front end. Inner cylinder 23 is
attached to front plate 21' so that the cylindrical axis is aligned
with axis AX, and such that cylinders 20 and 23 are substantially
concentric. Inner cylinder 23 has a smaller diameter than the
diameter of outer cylinder 20. Thus, the circular sidewalls of the
two cylinders delimit an annular compartment 24.
[0044] As previously mentioned, support fixtures 11 are disposed on
vertical support plate 10 in compartment 24. Compartment 24 serves
to provide a defined space for controlling the ambient through
which support fixtures 11 travel as vertical support plate 10
rotates about axis AX during the operation of preheating unit
1100.
[0045] Flowing heated air through compartment 24 may control the
ambient temperature in compartment 24.
[0046] Heated air obtained from conventional sources (not shown)
may be first supplied or fed into inner cylinder 23's compartment
24'. Alternatively, or additionally, air may be heated using heat
sources such as resistive heating elements (not shown) within
compartment 24'. The heated air passes from inner cylinder 23 into
compartment 24 through holes or openings AW in cylinder 23's walls.
The heated air supply is at a sufficiently high temperature to
provide an ambient temperature in compartment 24, which
substantially corresponds to a predetermined temperature. This
predetermined temperature, (as previously mentioned) is the
preparatory temperature to which subassemblies are preheated for
subsequent resin impregnation processes. The desirable preparatory
temperature may, for example, be a temperature in the range of
about 120.degree. C. to about 160.degree. C. depending on the
resins used. For uniform and reproducible resin impregnation it is
also desirable that subassemblies 13 be uniformly heated. The
number, size, and distribution of openings AW in cylinder 23's
walls may be designed to ensure even circulation of heated air
through compartment 24 to aid in maintaining a uniform ambient
temperature in compartment 24. Additionally, as previously
described with reference to FIG. 2a, support fixtures 11 hold
subassemblies 13 in an open cage-like structure. The openings in a
cage-like structure, for example, the openings between angularly
spaced ribs 14 (see FIGS. 2a and 2b) expose substantially all
surfaces of subassemblies 13 to the heated air flow circulating in
compartment 24. This direct exposure to the heated air flow may aid
in raising subassemblies 13 temperature rapidly and uniformly to
the ambient temperature.
[0047] FIG. 3 also illustrates details of an exemplary pattern by
which support fixtures 11 are disposed on vertical support plate 10
in compartment 24. The pattern is designed to increase the batch
size of subassemblies 13 that may be processed simultaneously in
preheater unit 1100. Support fixtures 11 are organized as arrays
11', 11", and 11'", and disposed on concentric circles with radii
R1, R2, and R3 (from axis AX), respectively. Support fixtures 11
within any one of the three arrays are disposed with substantially
equal radial angular spacings between adjoining support fixtures 11
of the same array along the circumference of the respective circle
on which the array is disposed. However, angular positions of
support fixtures 11 of any one array are shifted relative to the
angular positions of support fixtures 11 of another array. The size
of the angular shift may, for example, be about one half the radial
angle extended by the diameter of a support fixture 11 disposed in
the arrays. An angular shift of this size is illustrated in FIG. 3
as the spacing d between vertical lines 99 passing through the
centers of two proximate support fixtures 11 disposed on
neighboring arrays 11" and 11'". A similar pattern of support
fixtures may be chosen for other units in station 1000, for
example, for unit 1300 (FIG. 6). Such a distribution pattern
increases the number of support members present in compartment 24.
It will be understood that the exemplary pattern shown in FIG. 3 is
only illustrative. Alternative disposition patterns of support
fixtures 11, which may be more or less dense than the exemplary
pattern, may be chosen in accordance with the principles of the
invention.
[0048] The pattern that is used may be chosen with consideration to
the total number of support fixtures 11 in compartment 24, the time
that vertical support plate 10 takes to accomplish a revolution
about axis AX, and the time it takes to heat subassemblies 13 to
the desired predetermined temperature. Loading and unloading
operations from a support fixture require that the support fixture
be stopped in front of aperture 25. Preferably, the chosen pattern
is such that all of the support fixtures 11 are fully utilized
(i.e., loaded at all times), and that any newly loaded subassembly
13 is heated to the desired temperature in one revolution of the
vertical support plate 10. Under such operating conditions, the
operations of unloading a processed subassembly and loading an
unprocessed subassembly from any support fixture 11 in compartment
24 may be accomplished at the same time while the support fixture
is stopped in front of aperture 25 after one revolution around axis
AX. Such operating conditions may minimize the process time and
increase workstation throughput.
[0049] Loading and unloading subassemblies from a plurality of
support fixtures 11 in compartment 24, after every revolution of a
support fixture 11, requires intermittent rotation of vertical
support plate 10 about axis AX. Stopping periods during which
subassemblies may be loaded/unloaded separate the periods of
intermittent rotation. For the support fixture pattern shown in
FIG. 3, for example, vertical support plate 10 rotates through an
angular distance d between the intermittent stops. At this angular
periodicity of intermittent rotation, support fixtures in arrays
11', 11" and 11'" that are at sequentially consecutive angular
separations d, may be aligned and stopped in front of aperture 25
one at a time in sequence by array.
[0050] Further details of resin impregnation unit 1200 are now
described with reference to FIGS. 4 and 5. FIG. 4 shows a sectional
view as seen from directions 4-4 of FIG. 1. FIG. 5 is an enlarged
view of resin impregnation unit 1200. Resin impregnation unit 1200
includes vertical support plate 30, which is rotatable about axis
AX1. The structure and rotational mounting of vertical support
plate 30 may be similar to that of vertical support plate 10. In
particular, vertical support plate 30 may rotate about axis AX1 by
means of a motor drive (not shown) and a shaft of a bearing shaft
arrangement similar to shaft and bearing unit 12 which has been
described in detail with reference to FIG. 2 above. However, the
support fixtures 31 that are disposed on vertical support plate 30
are unlike support fixtures 11 described with reference to FIG. 2
above. Support fixtures 31 may be any suitable fixtures that
support the armature subassemblies 13 by shaft ends 13e and leave
wire coils portions of subassemblies 13 exposed to allow liquid
resin to be dispensed or trickled directly onto the wire coil
portions. Support fixtures 31 may, for example, be previously
disclosed fixtures similar to those described the references
incorporated herein.
[0051] Support fixtures 31 are evenly disposed in a circle on or
near the outer edge of support plate 30. Support fixtures 31 are
aligned so that wire coil portions of subassembly 13 loaded in a
plurality of support fixtures 31 are positioned to receive resin
from multiple dispenser units DU as vertical support plate 30
rotates around axis AX1.
[0052] For example, in FIG. 5 shows nine positions (schematically
represented as P.sub.1, P.sub.2, P.sub.3, P.sub.4, P.sub.5,
P.sub.6, P.sub.7, P.sub.8, and P.sub.9) directly below
corresponding dispensers DU as suitable positions for subassemblies
13 to receive dispensed resin. The multiple resin dispenser units
DU may be supported, for example, by central structure 37 or by any
other conventional support means. Nine support fixtures 31 may
align wire coil portions of nine loaded subassemblies 13 with
positions P.sub.1-P.sub.9 to simultaneously receive resin as
vertical support plate 31 rotates around axis AX1. Rotation of
vertical support plate 31 in one direction around axis AX1, for
example, in direction D1, may be used to advance consecutive
support fixtures 31 serially under dispenser units DU.
[0053] In operation, intermittent rotation of vertical support
plate in direction D1 may be used to sequentially advance and align
a consecutive series of support fixtures 31 with positions
P.sub.1-P.sub.9. The intermittent rotations may alternate with
stationary or pause periods. During a stationary period dispenser
units DU may trickle a quantity of the resin onto subassemblies 13
which are aligned with positions P.sub.1-P.sub.9 during the
stationary period. The resin impregnation processes generally
require resin application in several small doses over a period of
time rather than in a single dose or a few large doses to properly
saturate wire coils with resin. The quantity of resin dispensed
onto subassemblies 13 during a stationary period may correspond to
a single small resin dose. Multiple applications of the resin dose
to a subassembly 13 are obtained advancing the subassembly 13 first
through a series of nine possible applications at positions
P.sub.1-P.sub.9. Generally, one series of resin dose applications
through positions P.sub.1-P.sub.9 may provide a sufficient
cumulative quantity of resin called for by the manufacturing
process. However, if the manufacturing process calls for additional
series of resin dose applications, support fixture 31 holding
subassembly 13 may be revolved a full circle around AX2 to
reposition the subassembly 13 repeatedly through positions
P.sub.1-P.sub.9, for additional applications as desired.
[0054] In the operation of unit 1200, a preheated subassembly 13,
which has been unloaded from preheating unit 1100 through aperture
45, is quickly transferred into unit 1200 through aperture 36. The
preheated subassembly 13 may be loaded into an empty support
fixture 31 aligned with loading position P0. Apertures 45 and 36
are located proximately by design to minimize any cooling of
subassembly 13 during the transfer. Within a few intermittent
rotation periods of support plate 30, this freshly loaded
subassembly is advanced from loading position P0 through the series
of positions P.sub.1-P.sub.9. At each of these nine resin
application positions, small doses of resin are dispensed onto the
wire coil portions of the preheated subassembly. The preheated
subassembly then returns to toward position P0 by traveling almost
an entire revolution around axis AX1. For the subsequent
application of the small doses to be effective, the previously
applied resin doses should have fully flowed or settled into the
interwire spaces.
[0055] Resin impregnation unit 1200 includes optional heated air
flow compartment 35' designed to maintain the temperature of the
preheated subassemblies loaded into unit 1200 at a raised level
suitable for resin flow during the entire time the subassemblies
are in unit 1200. Maintaining the temperatures at the raised level
aids the settling flow of applied resin into interwire spaces.
Compartment 35' is disposed on a portion (indicated generally by
direction D*) of the upper half of front wall 35. Compartment 35'
may, for example, be shaped as the smaller of the cylinder segments
obtained by off-axis cut of a cylinder parallel to its diameter.
Top cylindrical wall 38 (FIG. 5) of compartment 35' may run
substantially parallel to upper cylindrical wall 33. Top
cylindrical wall 38 may be placed sufficiently below cylindrical
wall 33 to avoid interference with support fixtures 31 that move
through the space defined by wall 38 and upper portions of wall 33.
Cylindrical wall 38 also advantageously shields positions P.sub.1
to P.sub.9 from any resin that may accidentally drip from the
armatures traveling above positions P.sub.1 to P.sub.9.
[0056] Heated air is circulated in compartment 35' to provide a
heat source for maintaining a suitable high temperature ambient,
particularly in the space between wall 38 and upper portions of
wall 33. This high temperature ambient allows resin applied at
positions P.sub.1-P.sub.9 to a subassembly 13 to adequately settle
into wire coil spaces as subassembly 13 revolves across from
position P.sub.9 to P0 in direction D1.
[0057] In an alternative embodiment of unit 1200, known immersion
baths techniques may be used instead of dispensers DU to apply
resin to subassemblies 13. In this embodiment, liquid resin bearing
trays are placed vertically below resin application positions
P.sub.1-P.sub.9. The trays may be raised vertically so that the
bottom portions of subassembly 13 stacks are immersed in liquid
resin. This immersion coating of subassembly 13 stacks may be
scheduled to occur during stationary periods during which the
subassemblies 13 are aligned with positions P.sub.1-P.sub.9
(between the intermittent rotation of support 30).
[0058] In either embodiment of unit 1200, support fixture 31 may
rotate subassembly 13 about its axis 13' as it is advanced from
positions P.sub.1 to P.sub.9 so that the applied resin is evenly
distributed around subassembly 13 stack portions. The rotation of
subassembly 13 may be activated using known techniques such as
engaging a toothed pinion disposed on support fixture 31 in
conjunction with a moveable rack arrangement (not shown).
[0059] Further details of resin curing unit 1300 are now described
with further reference to FIG. 1 in conjunction with FIG. 6. FIG. 6
is a section view of station C as seen from directions 6-6 of FIG.
1.
[0060] Resin curing unit 1300 includes compartment 40 and an
optional cylindrical compartment 42. Compartment 40 may be used for
resin curing processes. Compartment 42 may be used to cool
subassemblies 13 that have undergone the resin curing process.
Subassemblies 13 are cooled, so that they may be output from resin
application station 1000 at temperatures substantially close to
manufacturing line ambient temperatures. The structural components
of resin curing unit may be similar or identical to those of
preheating unit 1100. Therefore, to avoid repetition, the
description of unit 1300 structural components is limited
herein.
[0061] Compartment 40 has an annular shape surrounding optional
cylindrical compartment 42 as shown in FIG. 6. Subassemblies 13
that are being processed in compartment 40 and compartment 42 are
held during processing in support fixtures 41 and 43, respectively.
Both support fixtures may have an open cage-like structure, which
may be similar or identical to the structure of support fixture 11
(FIG. 2a). Support fixtures 41 are disposed on vertical support
plate 39 in compartment 40. Support fixtures 43 are disposed on
vertical support plate 44 in compartment 42. Both support fixtures
may be disposed on the respective support plates in a manner
similar to that used for disposing support fixtures 11 on support
plate 10 (FIG. 2a). Both vertical support plates 39 and 44 rotate
around the same horizontal axis AX2. Vertical support plates 39 and
44 are attached to coaxial shafts 46 and 47, respectively. Shaft 47
passes through and is coaxially seated in shaft 46. Flanges 39' and
44' may be used to attach vertical support plates 39 and 44 to
their respective shafts 46 and 47. Both shafts 46 and 47 may be
driven independently of each other to rotate around axis AX2 by
respective motor drives (not shown) under the supervision of
station control unit 72 (FIG. 7).
[0062] Heated air is circulated through compartment 40 to provide a
heated ambient in which subassemblies 13 move through compartment
40 as shaft 46 rotates. The temperature of the heated air
circulated in compartment 40 may be suitably chosen to promote the
resin curing process. On completion of the resin curing process
subassemblies 13 are transferred to cooling compartment 42. Cool
air may be circulated through compartment 42 to promote rapid
cooling of the heated subassemblies 13. After the subassemblies
have cooled sufficiently for further processing through the
assembly line, the subassemblies 13 may be unloaded from
compartment 42.
[0063] As previously mentioned the transfer of subassemblies 13
between units 1100, 1200 and 1300 of station 1000 is accomplished
using gripper units 70 shown in FIG. 7. Gripper units 70 are
schematically represented in FIG. 7 as viewed along direction X in
FIG. 1. The gripper units 70a, 70b, 70c, 70d, and 70e are part of a
transfer system 700 disposed in front space 70' (FIGS. 2, 4 and 6)
in front of units 1100-1300. The operation of transfer system 700
may be understood with reference to FIG. 7.
[0064] Input subassemblies 13 placed in pallets 71 are delivered to
resin application station 1000 from downstream assembly line
locations on known conveyor apparatus. Pallets 71 stop at position
T1 on the left side of unit 1100. Similarly, empty pallets 72 are
made available at position T2 on the right side of unit 1300A for
transport of output subassemblies 13 that have been processed
through resin application station 1000.
[0065] With reference to FIG. 7, gripper 70a may be assigned to
load input subassemblies into unit 1100. Similarly, gripper unit
70b may be assigned to unload preheated subassemblies 13 from unit
1100, and to load preheated subassemblies 13 in unit 1200. Gripper
unit 70c may be assigned to unload resin impregnated subassemblies
13 from unit 1200 and to load the resin impregnated subassemblies
13 in unit 1300. Further, gripper unit 70d may be assigned to
unload resin cured subassemblies 13 from unit 1300, and to reload
the resin cured subassemblies 13 in compartment 42 of unit 1200.
Gripper unit 70e may be assigned to transfer cooled subassemblies
from compartment 42 of unit 1300 to waiting pallet 72 for transport
to location downstream from station 1000.
[0066] Input subassembly 13 received in pallet 71 at position T1
should preferably be loaded in the next available empty support
fixture 11 which is aligned with aperture 25. It will be understood
that a support fixture in any of units 1100, 1200, and 1300 becomes
empty and available for loading after a processed subassembly has
been unloaded from the support fixture. For example, in unit 1100
support fixture 11 may become empty and available when a preheated
subassembly 13 is unloaded from it. Empty support fixture 11 may
belong to any one of three support fixture arrays 11', 11", 11'" in
unit 1100. Route RT1 schematically represents a path (H) extending
from position T1 toward aperture 25. Three alternative route
branches V emanate from RT1 across aperture 25. The three route
branches V alternatively lead to a support fixture in arrays 11',
11", or 11'". To transfer input subassembly 13 from pallet 71 to
unit 1100, gripper unit 70a first travels along route RT1 to
collect input subassembly 13 from pallet 71. Then, gripper unit 70a
travels back along RT1, and along an appropriate branch V
corresponding to the array with empty support fixture 11 to load
subassembly 13 in unit 1100.
[0067] Similarly, route RT2 schematically represents a path (H)
extending from unit 1100 toward aperture 36 in unit 1200. The three
alternate branch lines V extend from aperture 25 to connect with
route RT2. Preheated subassembly 13 which is unloaded from support
fixture 11 aligned with aperture 25 is transferred by gripper unit
70b along the appropriate branch line corresponding to the array of
support fixture 11, and moved along route RT2 toward aperture 36 to
a position P*. Position P* is located to the side of an available
empty support fixture 31 aligned with position P0 (FIG. 5) in
aperture 36. Position P* is located to the side of position P0 to
account for the fact that support fixtures 31 are designed to be
loaded sideways (RT*) along a path parallel to the face of the
vertical support structure on which support fixtures 31 are
disposed through an opening parallel to their (fixture 31)
longitudinal axis.
[0068] Route RT3 schematically represents a path (H) extending from
unit 1200 to unit 1300. Three alternate route branches V emanate
from RT3 toward aperture 46 in unit 1300. The alternate route
branches V lead to corresponding alternate arrays of support
fixtures 41 in compartment 40. Similarly, route RT4 schematically
represents a path (H) extending from compartment 40 to compartment
42 along unit 1300. Finally, route RT5 schematically represents a
path (H) extending from compartment 42 of unit 1300 to an empty
pallet available at position T2 to the right of unit 1300. The
transfer of processed subassemblies 13 along routes RT3, RT4, and
RT5, by gripper units 70c, 70d and 70e, respectively, occurs in
fashion similar to that described for subassembly transfers along
paths RT1 and RT2.
[0069] It will be understood that the two-dimensional
representation of routes RT1, RT2, RT3, RT4 and RT5 in FIG. 7 is
schematic and for purpose of illustration only. For example, in
FIG. 7 branches V are shown as being vertical. In reality, branches
V represent movement of the gripper units through corresponding
apertures in to and out of units 1100-1300 along directions
13a-13b, a movement which is more accurately described as being
perpendicular the page containing FIG. 7.
[0070] Further, it will be understood that gripper units 70 are
capable of moving in 3-dimensional paths. FIG. 7a shows an enlarged
view of one of the gripper units 70 shown in FIG. 7. With reference
to FIG. 7a, gripper unit 70 is provided with tongs 80 for gripping
the shaft of armature subassembly 13. Tongs 80 are supported on
base 81. Base 81 may, for example, be a movable X-Y stage. Tongs 80
may be movable in the Z direction perpendicular to the plane of
which the X-Y stage. Conventional drive mechanisms such as
motorized drives and gear mechanisms may be used to move tongs 80
and stage 81. For clarity these drive mechanism are omitted from
FIGS. 7 and 7a.
[0071] To schedule the efficient flow of work through station 1000,
The intermittent rotations of vertical supports plates 10, 30, 39
and 44 (in compartments 24, 35, 40 and 42, respectively) may be
synchronized so that support fixtures are available for loading and
unloading operations at apertures 25, 36, 46 at appointed times.
This synchronization may be obtained by suitably programming
control unit 72, which supervises the motor drives that rotate
vertical supports 10, 30, 39 and 44. Control unit 72 may also
supervise gripper units 70a-70e to co-ordinate the transfer of the
subassemblies in a synchronized manner.
[0072] FIG. 8 lists important control steps that control unit 72
may, for example, perform to achieve the synchronism between units
1100, 1200 and 1300. With reference to FIG. 8, control unit 72 may
perform subassembly transfer operations T1a-T1e substantially
simultaneously within a time range T1. Time range T1 encompasses
the periods of pause in the intermittent rotation of all the
vertical support plates in the units. Next, within a range of time
T2, control unit may perform intermittent rotation operations
T2a-T2d, substantially simultaneously within a time range T2. Thus
time range T2 encompasses the periods of rotation in the
intermittent rotation of all the vertical support plates in the
units. After, T2, control unit may perform operations such stopping
the rotational movements and carrying out fixture alignment
operations T3a-T3d substantially simultaneously within a time range
T3. After which time, control unit 72 may initiate the next cycle
of subassembly transfer operations T1a-T1e. One skilled in the art
will appreciate that the present invention can be practiced by
other than the described embodiment, which is presented for
purposes of illustration and not of limitation.
* * * * *