192 clutches and power-stop control – Vortex-flow drive and clutch – Including drive-lockup clutch
Patent
1998-07-02
1999-12-28
Marmor, Charles A
192 clutches and power-stop control
Vortex-flow drive and clutch
Including drive-lockup clutch
19211334, F16H 4502
Patent
active
060068779
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a hydraulic clutch.
BACKGROUND OF THE INVENTION
Since the introduction of automatic transmissions, hydrodynamic torque converters have been the connecting link between a prime mover and the transmission proper. Because of the slip, a converter makes a comfortably smooth start possible. At the same, it time absorbs irregularities in the rotation of the combustion engine. Additionally, a great starting torque is made available by the torque increase conditioned by principle.
Strictly speaking, a converter generally comprises a converter housing, an impeller, a stator and a turbine wheel. Because of the torque being transmitted by the hydrodynamic forces from the impeller, via the stator, to the turbine wheel, slip results between the impeller and the turbine wheel. This causes a loss in efficiency.
To improve the efficiency, a bridge clutch was introduced which bridges the converter at certain rated speeds. The bridge clutch can be fitted before the turbine wheel, that is, between the converter housing and the turbine wheel, or behind the impeller, that is, between the impeller and another transmission unit.
The bridge clutch's disadvantage is the loss of the absorption of the vibration generated by the differential speed between the turbine wheel and impeller. To compensate for this, an additional shock absorber must be applied or the clutch itself must be designed as a shock absorber.
As a consequence of limited space conditions within the converter and of the complicated vibration systems of an automatic transmission, mechanical torsional shock absorbers cannot be designed so that the bridge clutch can be engaged already at low engine speeds and in the lower gears. Otherwise low, dull booming sounds will emanate throughout the body. In modern torque-optimized engines with high engine torques, at speeds slightly above the idling speed rigid power trains must already be used to prevent twisting thereof. Thereby the inherent frequency is moved to higher speeds, thus intensifying the problem of booming noises in the body.
Powerful transverse engines, having great capacity, increasingly require a narrow converter design. A mechanical torsion absorber thus creates considerable problems.
A bridge clutch, with regulated slippage, already makes engaging the converter at low driving speeds possible, absorbing the vibrations in critical speed ranges by the bridge clutch slip, reducing the cost of the torsional shock absorber and further reducing the consumption of benzene.
Torsional vibrations are generated in the drive train as a result of an angular acceleration of the crankshaft followed by a delay due to the compression in the next cylinder during each ignition of the combustible mixture in a cylinder. The angular speed thereby fluctuates between a maximum and a minimum.
As the engine speed increases, the torsion irregularity decreases proportionally 1
. At a speed of typically about 2,000 1/min, values of speed fluctuation are reached which scarcely decrease further as the engine speed increases. The curve of the angular deflection is proportionally 1
while the vibration range of the angular acceleration is almost independent of speed. Because of this, as a rule, above about 2,000 engine revolutions the bridge clutch can remain engaged during traction operation. Below 2,000 engine revolutions, the torsion irregularity suddenly increases so that the bridge clutch must be operated disengaged or adjustedly slipping.
During the engine coasting operation, the gas pressure in the cylinder is substantially less than during a traction operation, whereby the critical range moves to higher speeds. The vibration range of the angular acceleration thereby intensively increases as the engine speed increases. Body booms in the overrun are therefore detected mostly at speeds way above 2,000 1/min. For a comfortable drive the bridge clutch must, in this case, be disengaged or regulated.
In order to achieve a sufficient absorption of the torsion vibration, a slip of up to about from 2% to 3% is neede
REFERENCES:
patent: 4462492 (1984-07-01), Mueller
patent: 4674616 (1987-06-01), Mannino, Jr.
patent: 4930608 (1990-06-01), Schenk et al.
patent: 5209330 (1993-05-01), MacDonald
patent: 5248016 (1993-09-01), Umezawa
patent: 5310033 (1994-05-01), Shibayama
patent: 5669474 (1997-09-01), Dehrmann et al.
patent: 5732804 (1998-03-01), Wienholt
patent: 5799763 (1998-09-01), Dehrmann
Dipl. -Ing. (FH) W. Forte, "Betriebs-und Leerlaufverhalten von naBlaufenden Lamellenkupplungen", VDI Berichte. Nr. 649, 1987, pp. 335-358.
Marmor Charles A
Rodriguez Saul
ZF Friedrichshafen AG
LandOfFree
Hydraulic clutch for high friction applications 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 clutch for high friction applications, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydraulic clutch for high friction applications will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2376508