Joints and connections – Member deformed in situ – By piercing
Reexamination Certificate
2000-02-18
2002-08-20
Browne, Lynne H. (Department: 3629)
Joints and connections
Member deformed in situ
By piercing
C403S282000, C411S181000
Reexamination Certificate
active
06435758
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a connection arrangement for coupling a hydrodynamic torque converter to a rotating shaft so that the hydrodynamic torque converter is fixed with respect to rotation relative to the rotating shaft, the connection arrangement comprising at least one fastening element arranged at a converter housing of the torque converter.
2. Description of the Related Art
A prior art connection arrangement for connecting a hydrodynamic torque converter to a rotating shaft is known, for example, from German reference DE 44 24 989 A1. The accompanying
FIG. 3
shows a torque converter
110
with a converter housing
112
having a housing cover
134
. A turbine wheel
114
—shown schematically—is arranged in the interior of the converter housing
112
so that the turbine wheel
114
is rotatable relative to the converter housing
112
. The turbine wheel
114
has a turbine wheel shell
116
and a turbine wheel hub
118
that is coupled or can be coupled in a manner known per se with a driven shaft such, for example, as a transmission input shaft
120
, so that it is fixed with respect to rotation relative to the driven shaft. The torque converter
110
also has a lockup clutch
122
with a clutch piston
124
which is displaceable in the axial direction and has a radial outer area
126
on which a friction facing
128
may be arranged which can be pressed against a substantially flat friction surface area
130
at an inner surface
132
of the housing cover
134
of the converter housing
112
. Further, a centering pin
136
is secured to the housing cover
134
such, for example, as by welding. The centering pin
136
engages in a centering opening
138
of a rotating shaft
140
—shown schematically—and accordingly provides a centering of the torque converter
110
with respect to this rotating shaft
140
. The rotating shaft
140
may, for example, comprise a crankshaft of an internal combustion engine. A plurality of fastening elements
44
are secured successively along a circumferential direction about the axis of rotation A by a weld to an outer surface
142
of the converter housing
112
which faces in the axial direction toward the rotating shaft
140
. These fastening elements
144
are nut elements with an internal thread
146
.
FIG. 3
also shows a connection plate
148
such, for example, as a flex-plate which has openings
150
in a radial inner area. The openings
150
may be penetrated by screw bolts, not shown, to secure the connection plate
148
to the rotating shaft
140
. A radially outer area of the connection plate
148
also has an opening
152
associated with each fastening element
144
and through which screws may be screwed into the fastening elements
144
to join the converter housing
112
to the rotating shaft
140
such that it is fixed with respect to rotation relative to it.
In this type of connection arrangement, in which the fastening elements
144
are secured to the converter housing
112
by welding, subsequent machining steps are required after this welding process is carried out to restore the converter housing
112
, i.e., the cover
134
thereof, to its desired shape. Welding is prized in the automotive industry for its excellent connection stability. However, because of the heat introduced into the material of the housing cover
134
during the welding process, the housing cover
134
is at least slightly warped. Even the slightest warp cannot be tolerated because housing cover
134
forms the counter-friction surface
130
for the lockup clutch
122
. Therefore, a cutting machining step is required to restore exact true running of the cover
134
and housing
112
. This cutting machining step increases the number of necessary work steps and impairs strength especially in the region of the surface of the converter housing
112
.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a connection arrangement for coupling a hydrodynamic torque converter to a rotating shaft such that the hydrodynamic torque converter is fixed with respect to rotation relative to the rotating shaft and so that the integrity of the torque converter is not impaired, especially in the region of the converter housing, during the connection process.
According to an embodiment of the present invention, this object is met by a connection arrangement for coupling a hydrodynamic torque converter to a rotating shaft so as to be fixed with respect to rotation relative to it, wherein the connection arrangement comprises at least one fastening element arranged at a converter housing. The at least one fastening element is arranged at the converter housing in that an engagement portion of the at least one fastening element meshes in a positive engagement with a receiving portion of the converter housing.
Accordingly, the present invention produces a positive-locking connection in lieu of the known method of connecting the fastening element and converter housing in a material engagement by welding. As a result, the present invention eliminates the introduction of heat into the material of the converter housing that is required for achieving the material-engagement welding connection. Consequently, the connection arrangement according to the invention does not impair the operating behavior or the integrity of the torque converter in the area of the housing of the torque converter, thereby eliminating the requirement for any additional subsequent machining processes for removing the impermissible deformations of the converter housing caused by the connection process.
In the connection arrangement according to the invention, at least one positive engagement acting in the direction of the rotating shaft is preferably generated between the fastening portion of the at least one fastening element and the fastening portion of the converter housing. For example, the fastening portion of the converter housing may comprise a receiving recess and the fastening portion of the at least one fastening element may comprise an engagement portion which is insertable into the receiving recess.
In a preferred embodiment, the engagement portion of the at least one fastening element is constructed so that it widens toward its free end and has a maximum outer dimensioning, i.e., an outer diameter, which allows for the insertion of the engagement portion into the receiving recess. That is, the engagement portion has a tapering with an increasing diameter toward its free end. Furthermore, a deformation area is provided at the at least one fastening element, wherein, when the engagement portion engages at least partially in the receiving recess, the deformation area acts in at least some areas on the material area of the converter housing surrounding the receiving recess and deforms this material area in such a way that it engages behind the tapering engagement portion. Accordingly, it is necessary only to push the engagement portion of the at least one fastening element into the respective receiving recess and to press the fastening element into this receiving recess, wherein the positive engagement arrangement is formed automatically due to the configuration of the fastening element.
To minimize the impairment to the stability of the converter housing and to prevent the occurrence of sealing problems in the torque converter, the receiving recess associated with the at least one fastening element comprises a recess in the form of a pocket hole which is open toward the outside of the converter housing.
To achieve a stable positive-locking engagement, the at least one fastening element may be formed from metal, sintered material or a combination material, for example, a rubber-metal combination.
Further, the connection arrangement according to the invention may comprise a plurality of fastening elements arranged successively in a circumferential direction about an axis of rotation.
The present invention is also directed to a hydrodynamic torque converter with the connection arrangement described above.
Cohen & Pontani, Lieberman & Pavane
Cottingham John R.
Mannesmann Sachs AG
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