Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2001-09-14
2004-01-13
Binda, Greg (Department: 3679)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S889500, C029SDIG002
Reexamination Certificate
active
06675457
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Technical Field
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
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 torsional vibrations generated between the engine and the transmission of the vehicle during the mechanical engagement of the lock-up clutch, or torsional vibration damper.
Specifically, torsional vibration dampers include a driven or retainer plate and a drive plate. Referring to the prior art retainer plate
100
of a conventional torsional vibration damper (not shown) detailed in
FIG. 1
, the 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 plurality of compression springs
110
, critical to the dampening function of the torsional vibration damper, are disposed in the generally L-shaped channel
108
. 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
112
to assist in retaining the springs in the generally L-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 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 channel
108
during assembly and operation of the torsional vibration damper.
The incorporation of the spring support brackets
112
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 U.S. Pat. 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
FIG. 1
, the retainer plate of the '803 patent also includes a central plate segment and an annular periphery having a distal end. The annular periphery of the retainer 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 generally C-shaped channel, the annular periphery is only partially curled. As such, the annular periphery of the '803 patent is not sufficiently 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.
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 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 supplemental construction at an outer periphery of the drive plate to assist the retainer plate in retaining the springs during operation of the torsional vibration damper by encompassing at least a portion of a circumference of the springs. In sum, similar to retainer plate disclosed in
FIG. 1
, the retainer plate disclosed in the '803 patent must additionally incorporate vertical support walls 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 costs to the drive plate of the torsional vibration damper.
Due to the inefficiencies 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.
SUMMARY OF THE INVENTION AND ADVANTAGES
A method for manufacturing a one-piece torsional 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 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 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 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 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 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.
REFERENCES:
patent: 2219591 (1940-10-01), Hiester
patent: 2221800 (1940-11-01), Johnson
patent: 3964412 (1976-06-01), Kitsuda
patent: 4139995 (1979-02-01), Lamarche
patent: 4449621 (1984-05-01), F'Geppert
patent: 4890706 (1990-01-01), Miura et al.
patent: 4903803 (1990-02-01), Koshimo
patent: 4908924 (1990-03-01), Tsuruta et al.
patent: 5209330 (1993-05-01), Macdonald
patent: 5947243 (1999-09-01), MacDonald
patent: 5964328 (1999-10-01), Fallu et al.
Redmond Daniel W.
Ross William
Binda Greg
Clark Hill PLC
Tesma International Inc.
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