192 clutches and power-stop control – Vortex-flow drive and clutch – Including drive-lockup clutch
Reexamination Certificate
2003-07-30
2004-12-21
Rodriguez, Saul (Department: 3681)
192 clutches and power-stop control
Vortex-flow drive and clutch
Including drive-lockup clutch
C192S111400, C192S113360
Reexamination Certificate
active
06832673
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a hydrodynamic coupling device, especially a hydrodynamic torque converter, including a housing arrangement, a turbine wheel, which rotates around an axis of rotation in the housing arrangement, and a bridging clutch arrangement for the optional production of a torque-transmitting connection between the housing arrangement and the turbine wheel. The bridging clutch arrangement includes at least one first friction element, which can rotate together with the housing arrangement and which has at least a first friction surface, and at least one second friction element, which can rotate together with the turbine wheel and which has a second friction surface, which can be brought into frictional contact with a first friction surface of the first friction element. A first surface channel arrangement with first channel sections not open at the radially inner ends and second channel sections not open at the radially outer ends is provided in the friction surface of one of the friction elements. A second surface channel arrangement extending in the circumferential direction is provided in the friction surface of the other friction element, by means of which second channel arrangement the first channel sections and the second channel sections are brought into fluid-conducting connection with each other when frictional contact is established between the first friction element and the second friction element.
2. Description of the Related Art
A hydrodynamic coupling device in the form of a hydrodynamic torque converter is known from U.S. Pat. No. 6,047,806, as shown in
FIGS. 1 and 2
herein. This hydrodynamic torque converter
10
comprises a housing arrangement
12
with a housing cover
14
and a pump shell
18
, which forms an essential component of a pump wheel
16
. On its inner surface, this pump shell
18
carries a plurality of pump vanes
20
, arranged in a row in the circumferential direction around an axis of rotation A. In the interior space
22
of the housing arrangement
12
, furthermore, a turbine wheel
24
is provided. Radially on the outside, the turbine wheel
24
has a turbine shell
26
with a plurality of turbine vanes
28
supported thereon. Radially on the inside, the turbine wheel
24
can be connected nonrotatably to a power takeoff element
32
, such as a transmission input shaft, by way of a turbine hub
30
.
A bridging clutch arrangement
34
is provided to establish a direct torque-transmitting connection between the housing arrangement
12
and the turbine wheel
24
. In the example shown here, this coupling arrangement comprises a piston
36
, serving as a friction element, which is connected nonrotatably to the turbine wheel
24
, namely, to the turbine wheel shell
26
. On the side facing the housing cover
14
, the piston
36
carries a ring-like friction lining
38
. This lining can be made of suitable material such as fiber-reinforced polymer material to achieve the desired frictional relationships. In this case, the housing cover
14
serves as the opposing friction element; that is, the part of its surface which is axially across from the friction lining
38
serves as the opposing friction element. By increasing the fluid pressure in a space
40
, which is formed essentially between the piston
36
and the pump wheel shell
18
, and which also contains the turbine wheel
24
, with respect to a space
42
, which is formed essentially between the housing cover
14
and the piston
36
, the piston
36
, the radially inner part of which is able to slide along the turbine wheel hub
30
but is guided in a fluid-tight manner, is pressed toward the housing cover
14
so that the friction lining
38
arrives in frictional contact with the housing cover
14
.
FIG. 2
shows an axial view of the friction lining
38
, namely, a view of the side which is across from the housing cover
14
and which thus provides the friction surface
44
. A surface channel arrangement
46
includes a plurality of more-or-less radially oriented first channel sections
48
, arranged in sequence around the circumference, which are open at the radially outer ends and closed at the radially inner ends. In addition, a plurality of second channel sections
50
is provided, which are offset from the first channel sections
48
. These second channel sections
50
are closed at the radially outer ends and open at the radially inner ends. The first channel sections
48
and the second channel sections
50
are not connected directly to each other. A ring-shaped groove
54
, however, is provided as a second surface channel arrangement on the frictionally effective surface
52
of the housing cover
14
; this groove is formed as a circular ring passing around the axis of rotation A. The first channel sections
48
and the second channel sections
50
extend far enough from their radially outer and radially inner ends that they at least partially overlap the ring-shaped groove
54
. When frictional contact is established between the friction lining
38
and housing cover
14
, therefore, fluid from the first space
40
can enter the first channel sections
48
radially from the outside. From these first channel sections
48
, the fluid then passes into the ring-shaped groove
54
, from which the fluid then can emerge via the second channel sections
50
radially on the inside and thus arrive in the second space
42
. It is therefore ensured that, even when the bridging clutch arrangement
34
is active, fluid can be exchanged between the two spaces
40
,
42
and thus an exchange of fluid can take place in the entire interior space
22
to prevent the fluid from overheating. This is especially important in the case of converters of the two-line type. The first surface channel arrangement
46
with its channel sections
40
and
50
and the second surface channel arrangement with its ring-shaped channel
54
also ensure that the fluid flowing from the first space
40
to the second space
42
remains for a comparatively long time in the area of the frictionally active surfaces, so that an additional amount of heat can be carried away from this area, which is subject to very severe thermal loads.
So that defined fluid flow relationships between the first space
40
and the second space
42
can be provided in an arrangement of this type, the flow cross sections of the two surface channel arrangements
46
,
54
are provided with defined ratios. It has been found, however, that especially the circular ring-like groove
54
suffers from the problem of that its open flow cross section decreases over the course of its service life.
The essential reason for this is that the friction surface
44
, which makes contact with the housing cover
14
, is on a friction lining
38
, which is subject to a certain amount of abrasion. This abrasion, however, will not occur where the friction lining
38
, i.e., the area of the friction surface
44
thereof, is opposite the groove
54
, because there is no frictional contact here. Therefore, over the course of time, an excess thickness will develop, which projects more and more deeply into the groove
54
, thus reducing its flow cross section.
SUMMARY OF THE INVENTION
The task of the present invention is to provide a hydrodynamic coupling device of the type described above in which measures are taken to reduce the change in the fluid flow relationships which occur as a result of wear.
According to the invention, essentially for each part of the friction surface of the one friction element which is across from the second surface channel arrangement when in a first relative rotational position of the first friction element with respect to the second friction element, a second relative rotational position is provided, in which this same part of the friction surface is in contact with the friction surface of the other friction element, instead of being across from the channel, where there is no friction.
In the present invention, measures are taken to ensure that there are esse
Bauer Thomas
Baumann Roland
Engel Steffen
Juretzka Christoph
Sasse Christoph
Cohen & Pontani, Lieberman & Pavane
Rodriguez Saul
ZF Sachs AG
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