192 clutches and power-stop control – Vortex-flow drive and clutch – Including drive-lockup clutch
Reexamination Certificate
2002-06-11
2004-02-24
Rodriquez, Saul (Department: 3681)
192 clutches and power-stop control
Vortex-flow drive and clutch
Including drive-lockup clutch
C192S03000R, C192S055400, C192S208000, C192S212000
Reexamination Certificate
active
06695108
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a starting unit for use in drive systems, in particular for use in transmissions of vehicles, specifically having a hydrodynamic coupling and a lockup clutch.
Transmissions for use in vehicles, in particular in the form of automated manual transmissions or automatic transmissions, are known in a wide range of designs. A common factor of these variants is generally that the starting operation is effected by means of a clutch element in the form of a friction clutch or of a hydrodynamic converter. To effect power transmission in the other gear ratios, mechanical speed/torque conversion devices in various designs are generally connected downstream of these starting units. To avoid the introduction of torsional vibrations into the drive train, in particular into the transmission unit, there are generally devices for vibration damping, for example in the form of a torsional vibration damper, which are connected upstream of the transmission unit or are integrated in the latter in the region of the transmission input shaft. However, known integrated solutions involve the use of a vibration damper which is used only to compensate for or shift vibrations or additionally operates according to the friction damping principle. However, solutions of this type do not always give satisfactory results; in particular, stick-slip effects mean that it is impossible to completely rule out excitation of vibration during critical operating states of the drive train. A further drawback is that the intensity of damping achieved by damping devices of this type cannot be varied, or can only be varied with a very high level of outlay, over the operating range. Furthermore, the increasing demands with regard to environmental protection aimed at reducing emissions mean that the hydrodynamic converter in the transmission unit has to be closed earlier, with the result that the vibration excitation is considerably increased.
SUMMARY OF THE INVENTION
The invention is therefore based on the object of further developing a starting unit for a transmission unit for use in drive systems of vehicles in such a manner that vibration excitation is avoided in virtually any operating state, and its damping performance allows the possibility of adjustment. The space taken up is to be minimal, and the entire starting unit is to be suitable for achieving a high degree of standardization. Furthermore, it is to be distinguished by a low outlay on design control and is to be easy to integrate into the drive system or a force transmission unit, for example in the form of a geared transmission unit.
The solution according to the invention is described below.
The starting unit comprises a starting element in the form of a hydrodynamic speed/torque converter and a lockup clutch, the output sides of which are at least indirectly connected to one another in a rotationally fixed manner. Furthermore, there is a device for vibration damping, comprising at least one torsional vibration damper with hydraulic damping.
The torsional vibration damper is preferably connected functionally downstream of the lockup clutch, during force transmission in traction mode as seen from the drive to the output of the starting unit. The output ends of lockup clutch and speed/torque converter are for this purpose at least indirectly connected to one another in a rotationally fixed manner. In addition to the fact that a torsional vibration damper with hydraulic damping operates without wear, its use in a starting unit in a drive train offers the advantage that, on account of the avoidance of the sticking phases which are present when using a mechanical damping device in the form of a friction damper, excitation to vibrate can be virtually ruled out over the entire operating range. It is easy to adjust the damping intensity by means of the viscosity of the damping medium used or by varying the gap geometries, involving very little outlay. The damping which is established is also proportional to vehicle speed, which means that high frequencies or high amplitudes lead to a high level of damping.
The device for vibrational damping preferably comprises only one torsional vibration damper with hydraulic damping. In the installed position, during force transmission in traction mode, and as seen from the drive, the device for vibration damping, or at least the torsional vibration damper, is arranged:
a) spatially in front of the hydrodynamic speed/torque converter and behind the lockup clutch, or
b) spatially in front of the hydrodynamic speed/torque converter and in the same plane as the lockup clutch, or
c) spatially in front of the hydrodynamic speed/torque converter and the lockup clutch, or
d) spatially behind the hydrodynamic speed/torque converter and the lockup clutch.
In a particularly advantageous configuration of the starting unit, the device for vibration damping, in particular the torsional vibration damper with hydraulic damping, is part of the lockup clutch.
The torsional vibration damper with hydraulic damping functions as a highly elastic clutch, i.e. a clutch with a low rigidity for torque transmission between the drive of the starting unit and the output. The torsional vibration damper with hydraulic damping comprises a primary part, which can be at least indirectly coupled in a rotationally fixed manner to the drive or the output of the starting unit, and a secondary part, which can be at least indirectly coupled to the output or the drive, it being possible to couple the primary part and secondary part to one another by means of at least one damping coupling and spring coupling. For this purpose, there are first means for effecting a spring coupling and further second means for effecting a damping coupling, a functional division between the means for effecting the spring coupling and the further, second means for effecting the damping coupling preferably being provided. It is also conceivable for the functions to overlap. The means for spring coupling are used to effect the function of an elastic clutch. However, the term spring coupling is not to be understood as meaning only connection options using spring devices, but also any connecting elements which have a spring characteristic or an elastic behavior. The first means for effecting the spring coupling and the second means for effecting the damping coupling are preferably arranged in separate chambers which are arranged spatially apart from one another and are formed between the primary part and the secondary part. The means for effecting the damping coupling comprise at least one chamber which can be filled with hydraulic fluid and/or another damping medium and which in turn may be assigned means for influencing the damping performance. However, designs with an at least partial functional overlap between the means for spring coupling and the means for damping coupling are also conceivable.
The means for influencing the damping performance preferably comprise at least one throttle point which is assigned to a damping chamber and is integrated in the device for vibration damping or the torsional vibration damper with hydraulic damping. It is preferable for the throttle point to be arranged directly in the damping chamber.
An embodiment of a torsional vibration damper which is particularly compact and reliable in terms of its operation also comprises further, third means for limiting the twisting angle between primary part and secondary part, which are assigned to the damping chamber and divide the damping chamber into at least two part-chambers, which are connected to one another via at least one throttle point, the third means being involved in the formation of the throttle point. The following options exist in connection with the formation of the throttle point:
a) Integration of the throttle point in the third means;
b) Formation of the throttle point between the third means and the spatial limits of the damping chamber formed by the primary part and the secondary part.
This embodiment allows the damping performance to be influenced a
Brenner Franz
Hanke Wolfgang
Rodriquez Saul
Voith Turbo GmbH & Co. KG
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