192 clutches and power-stop control – Vortex-flow drive and clutch – Including drive-lockup clutch
Reexamination Certificate
2002-07-11
2004-06-01
Lorence, Richard M. (Department: 3681)
192 clutches and power-stop control
Vortex-flow drive and clutch
Including drive-lockup clutch
C192S070120, C192S212000, C192S113360
Reexamination Certificate
active
06742638
ABSTRACT:
CROSS-REFERENCE TO RELATED CASES
This application claims the priority of the commonly owned copending German patent application Serial No. 101 33699.3 filed Jul. 11, 2001. The disclosure of the aforesaid German priority application, as well as that of each US and/or foreign patent and/or patent application identified in the specification of the present application, is incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to improvements in apparatus which are known as torque converters, and more particularly to improvements in fluid-operated torque converters. Still more particularly, the invention relates to improvements in fluid-operated torque converters which can be utilized with advantage in the power trains of motor vehicles, especially for controlled transmissions of torque between driving and driven parts, e.g., between the rotary output element of a prime mover (such as the camshaft or the crankshaft of an internal combustion engine) and the rotary input shaft of an automatic change-speed transmission.
An apparatus of the above outlined character normally comprises a rotary housing which is non-rotatably connected to the output element of the prime mover, a pump which is driven by and can constitute an integral part of the housing, a turbine which can be driven by the pump through the medium of a body of fluid in the housing and can transmit torque to the input shaft of the transmission, an optional stator which (if utilized) is installed in the housing between the vanes of the pump and the turbine, and a bypass clutch or lockup clutch (hereinafter called bypass clutch) which can be engaged to bypass the pump, e.g., to transmit torque directly between the housing and the turbine or the input shaft of the transmission. Such torque converters often employ at least one additional constituent which is installed between an input part and an output part and serves as a torsional vibration damper, e.g., between a (first) hub of the turbine and a (second) hub affixed to the input shaft of the transmission. In addition to performing the above-enumerated tasks, the torque converter can further serve as a starter clutch between the engine and the automatic transmission in the power train of the motor vehicle.
The bypass clutch of the torque converter is arranged to become effective during certain stages of operation of a motor vehicle, and more specifically of the torque converter, for example, when there is no need for torque conversion and/or when it is desired to avoid or reduce energy losses due to pronounced slippage between the pump and the turbine. As already mentioned above, engagement of the bypass clutch entails direct transmission of torque between the housing and the output element(s) of the torque converter, e.g., from the housing (or from a part sharing all angular movements of the housing) to a hub or another part which shares the angular movements of the input shaft of the change-speed transmission. Otherwise stated, the transmission of torque (in the at least partially engaged condition of the bypass clutch) is effected as a result of frictional engagement between one or more parts rotating with the housing and one or more parts non-rotatably connected with the input shaft of the transmission.
The just discussed frictional engagement invariably or frequently entails the generation of heat, for example, in the region(s) where the friction linings of a disc often forming part of the bypass clutch engage the adjacent friction surface or surfaces, e.g., a friction surface on the housing of the torque converter and a friction surface on the piston of the bypass clutch. The generation of heat is attributable to slippage between the friction linings and the respective friction surfaces, a slippage which is often desirable for the sake of comfort to the occupant(s) of the motor vehicle and develops when the condition of the bypass clutch is caused to change from that of full disengagement to that of complete engagement or vice versa.
In accordance with presently known proposals, heating or overheating of the bypass clutch is sought to be prevented (or its intensity reduced) by establishing a pressure differential between the contents of two plenum chambers which flank the axially movable piston of the bypass clutch and contain bodies of a suitable converter fluid (e.g., oil). One of the chambers is adjacent the turbine and the other chamber is adjacent a wall of the housing of the torque converter. The friction linings on the disc of the bypass clutch are provided with grooves which permit the fluid to flow between the two chambers when the fluid pressure in one of the chambers exceeds the pressure of fluid in the other chamber. The circulating fluid cools the parts which, in the absence of heat withdrawal, are likely or bound to be overheated.
When the pressure differential between the contents of the two chambers assumes a certain value, the cooling action of the aforedescribed conventional cooling systems for the parts of the bypass clutch (i.e., the rate of fluid flow between the chambers by way of the grooves in the friction linings of the clutch disc) depends upon several parameters, primarily upon the dimensions and/or configurations of the grooves and the wear upon the parts which are provided with and/or are adjacent to the grooves. In order to compensate for wear, the rate of fluid flow in the grooves of friction linings of the clutch disc in the bypass clutch of a conventional torque converter is selected in such a way that the intensity of cooling action in a new torque converter exceeds the requirements; this is to ensure that the cooling action is still acceptable when the wear upon the friction linings reaches or approximates the maximum permissible wear.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a novel and improved fluid-operated apparatus which can be utilized as a torque converter and is constructed and assembled in such a way that the rate of fluid flow between the plenum chambers, and hence the cooling action upon its parts, is at least substantially constant during its entire useful life.
Another object of this invention is to provide a torque converter wherein the extent of wear upon the friction linings in the bypass clutch cannot influence, or cannot unduly influence, the rate of fluid flow between the chambers.
A further object of the invention is to provide a torque converter wherein the cooling of the friction surfaces provided on certain constituents of the bypass clutch remains satisfactory even when the wear upon such surfaces approximates or reaches the maximum permissible value.
An additional object of the instant invention is to provide a fluid-operated torque converter wherein the rate of fluid flow between the chambers when the torque converter is new need not exceed a value which approaches or matches an optimum value for the reasons of economy and/or of saving energy.
Still another object of this invention is to provide a novel and improved bypass clutch or lockup clutch for use in a fluid-operated torque converter.
A further object of the invention is to provide a bypass clutch wherein the heat transfer between the friction linings and the converter fluid (e.g., oil) is superior to that in presently known bypass clutches.
Another object of the invention is to provide a novel and improved friction lining for use in the bypass clutches of torque converters, especially torque converters which can be put to use in the power trains of motor vehicles.
An additional object of the invention is to provide a novel and improved method of enhancing or optimizing the exchange of heat between the fluid and the bypass clutch in the housing of a hydraulic torque converter.
Still another object of the invention is to provide a novel and improved method of controlling the flow of hydraulic fluid between the chambers in the housing of a fluid-operated torque converter.
A further object of the present invention is to provide a hydrodynamic torque converter with novel and improved means fo
Back Gunnar
Maienschein Stephan
Müller Bruno
Darby & Darby
Lorence Richard M.
LuK Lamellen und Kupplungsbau Beteiligungs KG
LandOfFree
Hydraulic torque converter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hydraulic torque converter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydraulic torque converter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3352669