Note: Descriptions are shown in the official language in which they were submitted.
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Docket No. 533809.027
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PATENT
STATOR LAMINATION NOL~1NG APPARATUS
Background of the Invention
The present invention relates to devices for
stamping notches in a stator lamination for an electric
motor, and more particularly, to full-automated stamping
devices having an indexing servo motor.
Typically, large electric motors include a
cylindrical stator core which is composed of a stack of
relatively thin, annular laminations made of a conductive
metal such as copper. Longitudinal grooves are formed to
extend along the interior surface of the stator core by
notching the inner peripheries of each of the laminations
which are aligned when the laminations are arranged in a
stack and rods are inserted through locating holes formed in
each lamination. Coils or rods formed from several
insulated wires (windings) are secured in such grooves. The
notches typically are formed by placing a stator lamination,
which has a central opening already formed, over a spindle
or hub on a turntable which indexes the lamination between a -
reciprocating die set which forms the notches. An exemplary
stator lamination jig system is disclosed in copending
United States Serial No. 08/368,917, filed January 5, 1995,
the disclosure of which is incorporated herein by reference.
Sometimes it is desired to skew the slot axes
relative to the stack axis. In this instance each
lamination is indexed a predetermined angular increment
relative to the preceding laminate so that when arranged in
a stack so that the locating holes are aligned, the axis of
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each groove is skewed or spiraled relative to the centra
axis of the stack. The amount of indexing has been achieved
by manually operated clamps and a manually adjusted stop
which controls the degree of travel in each rotation.
In another notching apparatus, a motor drives such
a laminate supporting turntable. The motor has a horizontal
output and includes a gear box to connect the motor to the
turntable. However, due to the inaccuracy of the manual
adjustments of the gears, loss of precision and/or excessive
adjustment time results.
Accordingly, there is a need for an apparatus
which accurately indexes the turntable for notching of a
stator lamination. Further, there is a need for accurately
controlling a stator lamination indexing mechanism.
Summary of the Invention
The present invention is a stator lamination
notching apparatus for notching the interior periphery of a
stator lamination. In a preferred embodiment of the
invention, the apparatus includes a servo motor which
selectively indexes a laminate supporting turntable. A
direct drive links the servo motor to the turntable. The
invention also includes a vertical output motor thereby
eliminating the need for a gearing system. Further, the
apparatus includes a programmable servo controller for
accurately controlling the indexing servo motor.
Accordingly, it is an object of the present
invention to provide a stator lamination notching apparatus
in which less gearing is required and, therefore, loss of
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precision from gear lock is minimized; a system which is
relatively easy to operate; and a system in which is likely
accurate and indexed by a computer control.
Other objects and advantages of the present
invention will be apparent from the following description,
the accompanying drawings and the appended claims.
Brief Description of the Drawings
Fig. 1 is a side elevational section of a
! preferred embodiment of the stator lamination notching
apparatus of the present invention; and
Fig. 2 is a schematic diagram of the operation of
the programmable control.
Detailed Description
As shown in Fig. 1, a stator lamination notching
apparatus, generally designated 10, is mounted on a work
table 11. In accordance with the present invention, the
apparatus 10 includes an indexing jig assembly 12 situated
above the worktable 11 and a motor assembly 14 situated
below the worktable. The apparatus 10 is adjustably bolted
to the work table 11.
The indexing jig assembly 12 includes an air
actuated support turntable 16 including a drive plate 18 for
supporting a stator lamination 20 thereon. The lamination
20 is shown and described in U.S. Application Serial No.
08/369,097 filed 1/05/95, the disclosure of which is
incorporated within by reference. A generally circular
hold-down plate 22 secures the lamination 20 on the
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turntable 16 from the top. The hold down plate 22 includes
inner 24 and outer 26 annular ridges to provide minimal
contact with the stator lamination 20. The indexing jig
assembly 12 also includes an upper assembly including a
stamping mechanism (not shown) and a substantially circular
plate 28 having a plurality of ejection cylinders 30
slidably supported thereon for removing the lamination 20
after the stamping operation is complete. A cylinder 31
controls the action of the ejection cylinders 30 on the
ejection plate 28. The indexing mechanism is capable of
rotating the turntable 16 a full 360 and can make up to
1,024,000 counts for high precision in notching.
The top assembly 12 further includes a bracket 32
which includes a bushing 34 that rotably receives a shaft 36
which is attached to the hold down plate 22. The shaft 36
is journaled into the bushing 34 and includes an enlarged
head 38 which prevents the shaft from sliding downwardly
through the bushing.
The turntable 16 is directly driven by the motor
assembly 14 which includes an indexing motor 40. The motor
40 is a vertical output motor and is coupled directly
without gears to an output shaft 42 which extends vertically
through the turntable 16 and engages the drive plate 18 to
act as the spindle for the turntable during the indexing
process which forms the notches in the lamination 20. A pin
50 is inserted within the output shaft 42 for attachment of
the outer rotating bushing 44 with the shaft 42. The
indexing motor 40 is therefore responsible for rotating the
output shaft 42 and providing power to the indexing
mechanism. Further, the output shaft 42 is coupled directly
without gears to the turntable 16.
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The motor 40 is preferably an indexing servo motor
which indexes along with the turntable. An important aspect
of this invention is that the servo motor and the turntable
are coupled directly to each other without the use of gears.
This allows a reduction in heat build up which is generally
encountered when dealing with gearing, the elimination of
gear lash, an increase in accuracy, reliability and control,
and a decrease in the cost of the apparatus when compared
with apparatuses which including gearing. Preferably, the
motor 40 and the drive shaft 42 are vertically coupled by a
direct drive.
The shaft 42 is situated within a bearing housing
44 and includes tapered roller bearings 46, 48 for easier
rotation of the shaft 42 within the housing 44.
A button 52 and a stationary sensor 54 are
included for accurately determining the home position. The
button 52 rotates with the outer bushing 44 and works in
combination with the stationary sensor 54 which is attached
to the servo controller 80 to set the apparatus in the home
position. In addition, the controller can precisely
determine the distance from home position during
initialization, as well as during the notching process, and
can determine when the motor has indexed a full 360 to
complete its rotation.
An outside spindle 56 is rotatively mounted on the
motor 40 and rotates with the outer bushing 44. Therefore,
the spindle 56, bushing 44, and turntable 16 all index
together by action of the indexing servo motor 40.
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Further, the motor 40 is supported on two U-shaped
motor supports 58,60 and a non-rotating rotor mounting plate
62. A servo controller 80 is connected to the motor on its
bottom end.
The whole turntable 12 and motor assembly 16
making up the apparatus 10 are capable of lateral movement
within the worktable 11. A motor support slide 62 slides
within a slot 64. When it is determined that they are in
the correct position, they are affixed to the table 11 by
two bolts 66, 68. A wedge block can be used to vary the
height of the assembly 10 to the workpiece 20 to be notched.
Then adjustment screws are used to adjust the left/right
movement.
A servo controller 80, in the form of a
programmable servo controller (PSC), is used for controlling
the indexing motor 14 with precision. The PSC 80 is
connected to the motor 40 and the sensor 54 and controls the
indexing of the table 18, the speed of indexing, and the
size of the notches as will be explained hereinbelow. The
sensor 54 associated with the PSC 80 senses and determines
the current position of the indexing means and aligns the
table 16 in a predetermined home position. Then the PSC 80
signals the completion of the notching of the laminate 20.
The motor 40 further includes an encoder to read the
instructions from the PSC 80.
Exemplary software which may be utilized for the
computer control is the "Motion Architect" by Parker
Hannifin Corp. which includes an operator interface. The
operator can control how many holes to punch or slots to
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punch in the lamination during the notching operation, as
well as the acceleration/deceleration profile for
controlling the speed of indexing. A number of stored
programs could be utilized for preset conditions.
Otherwise, the operator can customize the program in order
to select the number of notches or can program skips in the
notching process.
A flow chart of the computer control 80 is shown
in Fig. 2. First, the system is booted up 82. Then the
operator selects the number of slots to be notched in the
lamination 84. Next, the HOME position is selected 86. Or,
in the alternative, a change in the offset from home can be
selected during initialization, to align with other notches
in the laminate. If HOME is chosen, the computer aligns the
turntable at the home position 88. If OFFSET is chosen, the
computer asks for the new offset position 90 and designates
this new position as home 88. Then the ready light is
activated 92 and the cycle can be started 94. If positioned
correctly, the operator starts the system 96. If not, the
operator can again alter the offset position 98.
Having described the invention in detail and by
reference to preferred embodiments thereof, it will be
apparent that modifications and variations are possible
without departing from the scope of the invention defined in
the appended claims.
What is claimed is:
