Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR MANUFACTURING A t)NE-PIECE TORSIONAL
VIBRATION DAMPER RETAINER PLATE
BACKGROUND OF THfE INVENTION
I) TECHNICAL FIIELD
The subject invention relates to a method for manufacturing a one-piece
torsional vibration damper retainer plate for operation in a torque converter.
2) DESCRIPTION OF THE :PRIOR ART
10 Torsional vibration dampers are well known components in torque
converters. As appreciated, torque converters operate as a fluid coupling
between an output of an engine and an input of a transmission of a vehicle.
Additionally however, torque converters implement torsional vibration dampers
as lock-up clutches to dampen or reduce torsion,al vibrations generated
I S between the engine and the transmission of the vehicle during the
mechanical
engagement of the lock-up clutch, or torsional viibration damper.
Specifically, torsional vibration dampers :include a driven or retainer
plate and a drive plate. Refernng to the prior ari; retainer plate 100 of a
conventional torsional vibration damper (not shown) detailed in Figure 1, the
20 retainer plate 100 includes a central plate segment 102 and an annular
periphery
104 having a distal end 106. The annular periphery 104 of the retainer plate
100 extends upwardly at approximately 90° from the central plate
segment
102. As such, a generally L-shaped channel 108 is established between the
central plate segment 102 and the annular periphery 104. Continuing, a
25 plurality of compression springs 110, critical to the dampening function of
the
torsionai vibration damper, are disposed in the generally L-shaped channel
I08.
To retain the spring 110 in the L-shaped channel 108, a plurality of spring
support brackets 112 are mounted to the central plate segment 102. The
requirement of incorporating the plurality of spring support brackets I 12 to
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assist in retaining the springs in the generally I,-shaped channel 108 is
disadvantageous as will be realized further hereinbelow.
More specifically, the spring support brackets 112 include a support
segment 114 and a distal retention segment 116. For support purposes, the
5 support segment 114 of each spring support bracket 112 is rigidly mounted to
the central plate segment 102 of the retainer plate 100. Further, the distal
retention segment 116 of each spring support !bracket 112 angularly extends
toward the distal end 106 of the annular periphery 104 thereby spanning the
generally L-shaped channel 108 to retain the springs in the generally L-shaped
10 channel 108 during assembly and operation of the torsional vibration
damper.
The incorporation of the spring support brackets 1 I2 contribute
additional material, additional weight, and additional costs to the retainer
plate
100 of the torsional vibration damper.
A second conventional torsional vibration damper is disclosed in United
15 States Patent No. 4,903,803 (the '803 patent) to Koshimo. The '803 patent
discloses a conventional torsional vibration damper including a driven or
retainer plate and a drive plate. As with the retainer plate disclosed in
Figure 1,
the retainer plate of the '803 patent also includes a central plate segment
and an
annular periphery having a distal end. The anrsular periphery of the retainer
20 plate in the '803 patent is partially curled to establish a generally C-
shaped
channel between the central plate segment and. the annular periphery.
Continuing, a plurality of compression springs are disposed in the generally C-
shaped channel for dampening torsional vibrations. Although the annular
periphery of the retainer plate in the '803 patent is curled to establish a
25 generally C-shaped channel, the annular periphery is only partially curled.
As
such, the annular periphery of the '803 patent is not su~ciently curled to
independently retain the springs in the generally C-shaped channel, and the
retainer plate of the '803 patent only operates in conjunction with the drive
plate to retain the springs.
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Instead of independently retaining the springs, the '803 patent must
additionally incorporate vertical support walls stamped out of the retainer
plate.
The stamping of the vertical support walls adds time to the manufacture of the
retainer plate. Further, the stamping of the vertical walls directly out of
the
5 retainer plate necessarily forms "openings" dispersed throughout a
circumference of the retainer plate thereby detracting from the overall
structural integrity of the retainer plate in the '803 patent.
Also because the annular periphery of the '803 patent is only partially
curled, the drive plate that interacts with retainer plate must include
10 supplemental construction at an outer periphery of the drive plate to
assist the
retainer plate in retaining the springs during operation of the torsianal
vibration
damper by encompassing at least a portion of a circumference of the springs.
In sum, similar to retainer plate disclosed in Figure 1, the retainer plate
disclosed in the '803 patent must additionally incorporate vertical support
walls
15 that detract from the overall structural integrity of the retainer plate,
and the
drive plate disclosed in the '803 patent must additionally incorporate
supplemental construction at the outer periphery which contributes additional
material, additional weight, and additional cosia to the drive plate of the
torsional vibration damper.
20 Due to the ine~ciencies identified in such conventional torsional
vibration dampers, it is desirable to implement a method for manufacturing a
driven or retainer plate that retains at least one. spring without any
additional
components.
25 SUMMARY OF THE INVENTIOrf AND ADVANTAGES
A method for manufacturing a one-piece torsionai vibration damper
retainer plate having an annular periphery curled into a generally C-shaped
channel for retaining at least one spring comprises the step of disposing the
spring about the annular periphery of the retainer plate. The method further
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comprises, and is characterized by, the step of curling the annular periphery
of
the retainer plate into the generally C-shaped channel to substantially
surround
the spring to prevent the spring from being removed from the C-shaped channel
of the retainer plate during operation of the retainer plate. As appreciated,
the
5 generally C-shaped channel may retain more than one spring. That is, the
annular periphery of the retainer plate may be curled into a generally C-
shaped
channel for retaining a plurality of springs. Continuing, the step of curling
the
annular periphery is further defined by first partially curling the annular
periphery to receive the spring or springs and thereafter completing the
curling
10 of the annular periphery about the spring or springs. Additionally, the
method
incorporates the step of heat treating the retainer plate to change physical
properties of the retainer plate between the step of partially curling the
annular
periphery and the step of completing the curling of the annular periphery.
Accordingly, the subject invention provides a method for manufacturing
1 S a driven or retainer plate having an annular periphery curled into a
generally C-
shaped channel that substantially surrounds at least one spring to prevent the
spring from being removed from the C-shaped channel of the retainer plate
during operation of the retainer plate. As a result, the retainer plate
manufactured according to the subject invention independently retains the
20 spring in the generally C-shaped channel thereby requiring less material,
less
weight, and less cost than the conventional retainer plates of the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages of the present invention will be readily appreciated as
25 the same becomes better understood by reference to the following detailed
description when considered in connection with the accompanying drawings
wherein:
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Figure 1 is perspective view illustrating a conventional retainer plate;
Figure 2 is a perspective view illustrating a retainer plate of the subject
invention having an annular periphery curled into a generally C-shaped channel
to substantially surround at least one spring;
5 Figure 3 is a fragmentary cross-sectional view generally illustrating the
retainer plate of the subject invention in a torque converter of a vehicle;
Figure 4 is a partially cross-sectional schematic view of a blank of the
retainer plate according to the method of the subject invention;
Figure 5 is a partially cross-sectional schematic view of the retainer
10 plate stamped to form a central plate segment, a circumferential groove,
and an
annular periphery;
Figure 6 is a partially cross-sectional schematic view of the retainer
plate pierced to form a plurality of apertures in the central plate segment;
Figure 7 is a partially cross-sectional schematic view of the retainer
15 plate trimmed to a final diameter and pierced to form a central interior
rim and
hub opening;
Figure 8 is a partially cross-sectional schematic view of the retainer
plate with the annular periphery wiped to extend from the circumferential
groove;
20 Figure 9 is a partially cross-sectional schematic view of the retainer
plate with the annular periphery partially curled;
Figure 10 is a partially cross-sectional schematic view of the retainer
plate stamped to form a center step about the hub opening;
Figure 11 is a partially cross-sectional schematic view of the retainer
25 plate with the annular periphery finally curled independently retaining the
spring;
Figure 12 is a partially exploded perspective view illustrating the
annular periphery of the retainer plate partially curled and representing the
springs in spaced- relationship thereto; and
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Figure I3 is an enlarged fragmentary cross-sectional view illustrating
the annular periphery of the retainer plate partiially curled and completely
curled.
5 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the Figures, wherein like numerals indicate like or
corresponding parts throughout the several views, a driven plate or one-piece
torsional vibration damper retainer plate, manufactured according to the
subject invention is generally shown at 20. Referring initially to Figure 3,
the
10 retainer plate 20 manufactured according to the subject invention
mechanically
interacts with a drive plate 22 to establish a torsional vibration damper
assembly 24. The torsional vibration damper assembly 24 is integrally disposed
within a torque converter 26 of a vehicle (not ;shown in the Figures). The
retainer plate 20, more specifically, is mountedi to an outside facing 28 of a
15 turbine 30 of the torque converter 26 via a rivet 32. As appreciated, the
retainer plate 20 may be mounted to the turbine 30 in other manners including,
but not limited to, welding or mounting the retainer plate 20 via a nut and
bolt.
Although not specifically shown in Figure 3, the turbine 30 of the torque
converter 26 receives a forced fluid from an itr~peller of the torque
converter 26
20 to ultimately drive or turn an input shaft of a transmission of the
vehicle.
Referring now to Figure 2, the retainer plate 20 is a generally disc-
shaped unitary stamping of steel including a central plate segment 34 and an
annular periphery 36 having a distal end 38. A.s appreciated, the central
plate
segment 34 of the retainer plate 20 provides structural support to the
retainer
25 plate 20. The central plate segment 34 includes a plurality of apertures 40
for
receiving rivets, or other fasteners necessary to properly secure the retainer
plate 20 within the torque converter 26. The central plate segment 34
terminates at a central interior rim 42 thereby forming a hub opening 44 of
the
retainer plate 20.
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Continuing; the annular periphery 36 of the retainer plate 20 is curled to
form a generally C-shaped channel 46. The generally C-shaped channel 46 may
be otherwise fairly characterized as a generally semi-circular-shaped channel,
a
generally cup-shaped channel, or a generally ring-shaped channel. With
5 reference to the central plate segment 34 and the generally C-shaped channel
46, a plurality of offset sections 48 protrude from the central plate segment
34
into the generally C-shaped channel 46. Each of the plurality of offset
sections
48 includes first 50 and second 52 ends defining radially extending abutment
walls 54 (best shown in Figure 12) within the l;enerally C-shaped channel 46.
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The generally C-shaped channel 46 of the retainer plate 20
independently retains at least one spring 56. As appreciated, the spring 56
includes spring ends 58 having spring seats 60 that are integrally disposed
within each end 58 of the spring 56 for properly seating the spring 56 in the
S generally C-shaped channel 46. More specifically, the spring 56 is
independently retained in the generally C-shaped channel 46 of the retainer
plate 20 between the radially extending abutment walls 54. The spring 56
utilized in the subject invention preferably includes, but is not limited to,
a
compression spring. Also, the spring 56 utilized in the subject invention may
10 be of varying lengths depending on specific requirements of the damper
assembly 24. As shown specifically in Figure,. 2 and 12, the generally C-
shaped
channel 46 of the retainer plate 20 may retain a plurality of springs 56
without
varying the scope of the invention. The independent retention of the spring 56
or the plurality of springs 56 within the genertaly C-shaped channel 46 will
be
15 understood more completely herein below. Also as shown in Figures 2 and 12,
there are preferably four springs 56 retained in the generally C-shaped
channel
46 of the retainer plate 20 whereby two of the. four springs 56 have a larger
length than the other two of the of the four springs 56 in accordance with
performance requirements of the particular damper assembly 24.
20 A method for manufacturing the one-piece torsional vibration damper
retainer plate 20 having the annular periphery 36 curled into the generally C-
shaped channel 46 for retaining at least one spring 56 comprises the steps
that
follow and that are represented in Figures 4 through I 3 . As represented in
Figure 4, the method includes an initial blanking operation to generate a
blank
25 62 by stamping a predetermined size, diameter, and general shape of the
retainer plate 20 from a coil of steel such as a 1020 steel with carbon. As
represented in Figure 5, after the blank 62 is formed, the retainer plate 20
is
stamped to form the central plate segment 34 sand a circumferential groove 64
having radially-spaced inner 66 and outer 68 vvalls extending about the
central
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plate segment 34. As appreciated, the stamping of the retainer plate 20 is
generally a soft stamping process where particular attention is payed to not
tear
or otherwise damage any surface of the retainer plate 20. As a result, the
step
of stamping the retainer plate 20 to form the central plate segment 34 may
additionaIly incorporate a re-striking step or siteps to form finished
dimensions
of both the central plate segment 34 and the ciircumferential groove 64.
Continuing, the stamping of the retainer plate 20 is further defined by
forming the radially extending abutment walls 54 within the circumferential
groove 64 for positioning the spring 56 or springs 56 about the
circumferential
10 groove 64. For illustrative purposes, the radially extending abutment walls
54
are not shown in Figures 5 through 11. During the stamping, an integral corner
70 is formed which extends about the central plate segment 34 and into the
inner wall 66 of the circumferential groove 64. Also during the stamping, the
annular periphery 36 is formed which extends radially from the outer wall 68
of
15 the circumferential groove 64.
With reference to Figure 6, the method continues to include a first
piercing step to pierce the plurality of apertures 40 in the central plate
segment
34 of the retainer plate 20. The method may include other similar piercing
steps as required to form other apertures needed for mounting of the retainer
20 plate 20 at various locations within the torque converter 26. For example,
with
reference to Figure 7, the method includes the additional piercing step to
form
the central interior rim 42 thereby forming the hub opening 44 of the retainer
plate 20. As also shown in Figure 7, the subject method incorporates a step to
'trim' the annular periphery 36 of the retainer plate 20 to a predetermined
final
25 diameter. As appreciated, the final diameter ofthe annular periphery 36 is
predetermined based on geometry of the springs 56 ultimately disposed in the
generally C-shaped channel 46.
Refernng now to Figure 8, the methof, further includes the step of
wipiing the annular periphery 36 to extend the periphery 36 axially as an
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extension of the outer wall 68 of the circumferential groove 64. in other
words, the annular periphery 36 is bent from a horizontal position (Figure 7}
to
a vertical position (Figure 8}. After the step ojFwiping the annular periphery
36, the method continues by partially curling the distal end 38 of the annular
5 periphery 36 as represented by A in Figure 13 and shown generally in Figure
9.
This partial curling of the annular periphery 3ti will be described more
completely herein below. Next, with reference: to both Figure 10, the method
continues by adapting the central plate segment 34 to form a center step 72
about the hub opening 44 of the retainer plate 20, and by piercing additional
10 apertures as needed.
Referring now to Figure 12, the method next includes the step of
disposing the spring 56 about the annular periphery 36 of the retainer plate
20.
More specifically, the step of disposing the spring 56 about the annular
periphery 36 is further defined by disposing a plurality of springs 56 about
the
I S annular periphery 36 of the retainer plate 20. As discussed above,
disposing
the plurality of springs 56 about the annular pesriphery 36 does not influence
the
scope of the subject invention and, for conveniienee in describing, the method
will be described further in terms of the plurality of springs 56.
Continuing, the method, with reference; to Figure 13, is characterized by
20 curling the annular periphery 36 into the generally C-shaped channel 46 to
substantially surround the springs 56 to prevent the springs 56 from being
removed from the C-shaped channel 46 of the retainer plate 20 during
operation of the retainer plate 20. More specLfically, the step of curling the
annular periphery 36 is fiirther defined by partially curling the annular
periphery
25 36 (see A in Figure 13} to receive the springs >6 and thereafter completing
the
curling of the annular periphery 36 (see B in Figure 13) about the springs 56.
This will be described further herein below.
As introduced immediately above, the curling of the annular periphery
36 more specifically includes a first step of partially curling the annular
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periphery 36, and a second step of completing the curling of the annular
periphery 36 about the springs 56. The first sitep of partially curling the
annular
periphery 36 is represented in Figures 9, 12, and 13: As Figure 9 shows, the
method further includes the step of partially curling the annular periphery 36
5 . toward the integral corner 70. In particular, tlhis step occurs prior to
disposing
the springs 56 within circumferential groove 64. However, as Figure 12
shows, after the annular periphery 36 is partially curled, the springs 56 are
then
disposed within the circumferential groove 64. As discussed above, Figure 13
represents the partial curling of the annular periphery at A.
10 Furthermore,. after the annular periphery 36 is partially curled, the
method includes the step of heat treating the retainer plate 20 to change the
physical properties of the retainer plate 20 between the step of partially
curling
the annular periphery 36 and the step of completing the curling of the annular
periphery 36. More specifically, as the retainer plate 20 is heat treated, the
15 steel of the retainer plate 20 is hardened to improve the structural
integrity of
the retainer plate 20 and, in particular, the annular periphery 36 prior to
the
step of completing the curling of the annular periphery 36. The heat treating
process enables the step of completing the curling of the annular periphery
without permanent damage to the annular periiphery such as tearing or
20 complete breaking.
Also, between the step of partially curling the annular periphery 36 and
the step of completing the curling of the annular periphery 36, the method
preferably incorporates steps of deburnng anf. cleaning the retainer plate 20.
These additional steps are preferred in order promote clean and safe handling
25 of the retainer plate 20 in preparation for shiplping.
As discussed above, after the annular periphery 36 is partially curled,
but before the step of completing the curling c>f the annular periphery 36,
the
springs 56 are disposed about the annular periphery 36. As shown in Figure
1 l, after the springs 56 are disposed about the; partially-curled annular
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periphery 36, the annular periphery 36 is finally curled into the generally C-
shaped channel 46 to substantially surround the springs 56 to prevent the
springs 56 from being removed from the C-shaped channel 46 of the retainer
plate 20 during operation of the retainer plate 20. More specifically, the
5 second step of completing the curling of the annular periphery 36 occurs as
represented by B in Figure 13. That is, the curling of the annular periphery
36
toward the.integral corner 70 and about the springs 56 occurs. In curling the
annular periphery 36 toward the integral cornea 70 and about the springs 56,
the step of completing the curling of the annular periphery 36 is further
defined
IO by curling the annular periphery 36 at least beyond one half of a
circumference
of each spring 56.
Once the second step of completing the curling of the annular periphery
36 occurs, the circumferential groove 64 is recognized only as a portion of
the
annular periphery 36. Correspondingly, once lthe second step of completing the
15 curling of the annular periphery 36 occurs, the annular periphery 36 and
the .
circumferential groove 64 comprehensively establish the generally C-shaped
channel 46 far independently retaining the springs S6.
The final curling of the annular periphery 36 into the generally C-
shaped channel 46 is typically accomplished by a stamping process. However,
20 other metal forming processes, including, but not limited to, metal
spinning or
force flowing of the annular periphery 36 may also be implemented.
Additionally, as appreciated, these metal forming processes may also be
implemented to partially curl the annular periphery 36.
With reference now to Figure I l, the step of completing the curling of
25 the annular periphery 36, in sum, enables independent retention of the
springs
56 within the retainer plate 20. That is, the retainer plate 20 manufactured
according to the subject method invention does not necessitate the
incorporation of additional apparatus to retain the springs 56 within the
retainer
plate 20, and the torsional vibration damper assembly 24 operates optimally.
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The invention has been described in an illustrative manner, and it is to
be understood that the terminology which has been used is intended to be in
the
nature of words of description rather than of limitation.
Obviously, many modifications and variiations of the present invention
are possible in light of the above teachings. It is, therefore, to be
understood
that within the scope of the appended claims the invention may be practiced
otherwise than as speci$cally described.
