Endless belt power transmission systems or components – Pulley with belt-receiving groove formed by drive faces on... – Load responsive
Reexamination Certificate
1998-11-24
2001-02-13
Hannon, Thomas R. (Department: 3682)
Endless belt power transmission systems or components
Pulley with belt-receiving groove formed by drive faces on...
Load responsive
Reexamination Certificate
active
06186917
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to improvements in transmissions, and more particularly to improvements in continuously or infinitely variable transmissions of the type suitable for use in the power trains of motor vehicles.
A transmission of the type to which the present invention pertains comprises a first adjustable sheave or pulley which can be driven, for example, by the output element (such as the crankshaft or the camshaft) of an internal combustion engine in the power train of an automotive vehicle, a second adjustable sheave or pulley which can transmit torque to a clutch or to a differential in the power train of the vehicle, and at least one endless flexible element (such as a belt or a chain and hereinafter referred to as chain) which is trained over and can transmit torque between the first and second sheaves. As a rule, each sheave comprises a first flange which is rigid (e.g., of one piece) with a shaft, and a second flange which cannot rotate relative to but is movable axially of the shaft. It is also known to provide a transmission of the above outlined character with at least two plenum chambers which can receive a pressurized fluid from a suitable source, and with an annular sealing device (such as a sealing ring) which can serve to establish or to interrupt the flow of fluid between the chambers.
A transmission of the above outlined character is disclosed, for example, in published German patent application Serial No. 195 44 644. Such transmissions can employ a lip seal which can prevent the flow of fluid between two chambers when the pressure of fluid in one of the chambers is higher than that of the fluid in the other chamber but which is expected to permit the fluid to flow from the other chamber into the one chamber when the pressure of fluid is higher in the other chamber.
A drawback of such standard sealing devices is that a lip seal is likely to be shifted and/or tilted and/or otherwise deformed and/or displaced so that it is incapable of reliably permitting the flow of a fluid (such as oil) from one of the plural chambers into the other chamber or chambers when such flow is desirable or necessary for proper operation or functioning of the transmission.
OBJECTS OF THE INVENTION
An object of the invention is to provide a transmission of the above outlined character with a novel and improved sealing device which can regulate the flow of a fluid between several chambers, such as plenum chambers, in a reliable and predictable manner.
Another object of the invention is to provide a sealing device which is more reliable than heretofore known and presently utilized sealing devices.
A further object of the invention is to provide a simple, compact and relatively inexpensive sealing device which can be put to use in existing types of continuously or infinitely variable speed transmissions in the power trains of motor vehicles.
An additional object of the invention is to provide a transmission which embodies at least one sealing device of the above outlined character.
Still another object of the invention is to provide a novel and improved receptacle for a sealing device of the above outlined character.
Another object of the invention is to provide a transmission embodying a torque sensing, selecting and monitoring unit which, in turn, embodies a sealing device of the above outlined character.
A further object of the invention is to provide novel and improved adjusting means for the sheaves of the above outlined continuously or infinitely variable speed transmission.
An additional object of the invention is provide a sealing device which can reliably regulate (such as permit, prevent or throttle) the flow of a fluid between two or more plenum chambers of a continuously variable speed transmission under circumstances when a conventional sealing device fails to function at all or is unlikely to function in a predictable, desirable or required manner.
Still another object of the invention is to provide a novel and improved method of regulating the flow of a fluid (such as oil at superatmospheric pressure) between the chambers of a continuously variable speed transmission, e.g., a transmission which can be put to use in the power train of a passenger car, truck or another motor vehicle.
A further object of the invention is to provide a transmission wherein the flow of a fluid between the chambers of a torque monitoring device and/or between the chambers of adjusting means for one or both sheaves of the transmission can be regulated in the above outlined manner and by resorting to at least one sealing device of the above outlined character.
Another object of the invention is to provide an annular sealing device which can stand long periods of use in a continuously variable speed transmission, which can be mass produced at an acceptable cost, and which can be installed and/or removed and replaced in a simple and time-saving operation.
An additional object of the invention is to provide a power train which employs a transmission of the above outlined character.
SUMMARY OF THE INVENTION
The invention is embodied in a transmission which comprises a first adjustable rotary sheave or pulley (hereinafter called sheave) including coaxial first and second flanges one of which is movable axially toward and away from the other flange, a second adjustable rotary sheave or pulley (hereinafter called sheave) including coaxial first and second flanges with one of these flanges movable axially toward and away from the other flange, at least one endless flexible torque transmitting element (such as a chain) trained over the two sheaves, a source of pressurized fluid, adjusting means having at least two fluid receiving chambers and means for connecting at least one of the chambers to the source, and means for regulating the flow of fluid between the at least two chambers. The flow regulating means comprises at least one annular sealing device.
The at least one annular sealing device can comprise an annular radially outer portion, an annular radially inner portion, and an annular intermediate portion disposed between and connecting the radially inner and radially outer portions with each other. The radially inner and radially outer portions of the at least one sealing device can extend in the direction of a common axis of the three portions, and the intermediate portion can extend at least substantially radially of the common axis. The intermediate portion of the at least one sealing device can be located in a plane which is at least substantially normal to the common axis of the three portions, and at least a major part of each of the radially inner and outer portions can be located at one side of such plane.
In accordance with a feature of the invention, at least one of the radially inner and radially outer portions of the at least one sealing device can include a plurality of reliefs which are spaced apart from each other in a circumferential direction of the at least one of the radially inner and radially outer portions. If each of the radially inner and radially outer portions of the at least one annular sealing device has a set of reliefs, the distribution of such reliefs in or on one of the radially inner and radially outer portions may but need not be the same as the distribution of reliefs in or on the other of the radially inner and radially outer portions. At least one of the plural reliefs can have a substantially or exactly rectangular, square or L-shaped cross-sectional outline.
For example, the radially inner and/or the radially outer portion of the at least one sealing device can have between about 5 and 40 reliefs, preferably between about 20 and 30 reliefs. In accordance with a presently preferred embodiment, the radially inner and/or the radially outer portion can have close to or exactly 24 reliefs.
The reliefs can but need not always be at least substantially equidistant from each other (as seen in the circumferential direction of the respective (radially inner and/or radially outer) portion of the at least one sealing device).
The regulating m
Friedmann Oswald
Walter Bernhard
Darby & Darby
Hannon Thomas R.
LuK Getriebe-Systeme GmbH
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