Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-06-11
2001-04-10
Mullins, Burton (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S07500D, C310S06800R, C310S092000, C310S096000, C310S051000, C074S574300
Reexamination Certificate
active
06215213
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drive arrangement for a motor vehicle connectable to a crankshaft of an internal combustion engine and having a clutch system which includes an electric machine for damping torsional vibrations.
2. Description of the Related Art
A prior art clutch system with a flywheel mass is disclosed, for example, by German reference DE 196 09 043 C1. This flywheel mass device includes a first flywheel mass and a second flywheel mass. A primary flange which is permanently connected to a crankshaft of an internal combustion engine is part of the first flywheel mass which can be rotated relative to the second flywheel mass. These two flywheel masses form the flywheel disk of a friction clutch which is connected downstream from the flywheel masses. The second flywheel mass, also referred to as the secondary flywheel mass, can be connected to an output drive shaft via the friction clutch. The disadvantage with this type of prior art clutch system is that the damping capacity of the flywheel mass device is frequency-dependent. In particular, the damping capacity is limited at a maximum to predeterminable frequency ranges.
A prior art drive arrangement for hybrid vehicles is disclosed in German reference DE 43 23 601 A1 and comprises an internal combustion engine which can be coupled to an output drive shaft via an interposed clutch. This drive arrangement also includes an electric machine comprising a rotor designed as an external rotor which is connected to the output drive shaft. A friction clutch is arranged radially inside of the electric machine. When the clutch is disengaged, the electric machine does not influence the rotational behavior of the crankshaft. Rotational nonuniformities in the crankshaft may cause a tumbling movement of the crankshaft. The tumbling movement may severely load the bearings of the crankshaft and of the internal combustion engine and may cause nonuniform wear of the friction clutch, particularly the friction linings, during a clutch reengagement operation.
Because of the recent developments relating to ever more economical drive systems in relation to fuel consumption, internal combustion engines are becoming less and less uniform in terms of their rotational behavior. Such rotational nonuniformities may lead to severe loading of components in the drive train as mentioned above may result in premature material fatigue.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a powerful system for damping rotational nonuniformities in a drive train of a motor vehicle.
It is a further object of the present invention to provide a compact system for the damping of rotational nonuniformities in a drive train of a motor vehicle.
The object of the invention is achieved by a drive arrangement for a motor vehicle, comprising a crankshaft of an internal combustion engine and a clutch system for selectively connecting the crankshaft to an output drive shaft, the clutch system having first and second flywheel masses, the first flywheel mass being rotatable relative to the second flywheel mass and having a primary flange fixedly connected to the crankshaft, the clutch system further comprising an electric machine activatable for producing a torque counter to rotational nonuniformities occurring in the crankshaft and having a stationary portion comprising a stator and a rotor mounted on a rotor carrier, the primary flange of the first flywheel mass comprising a portion of the rotor carrier.
The drive arrangement of the present invention has an internal combustion engine with a crankshaft which can be connected to an output drive shaft via an interposed clutch system. The clutch system has at least two flywheel masses which are coupled to each other and, with the clutch engaged, can be rotated relative to each other. The first flywheel mass comprises at least one primary flange which is permanently connected to the crankshaft. This primary flange is part of a rotor carrier of an electric machine arranged in the drive train. This electric machine is permanently connected to the internal combustion engine so that even when the clutch is disengaged, the electric machine can introduce torques which are directed counter to the rotational nonuniformities generated by the internal combustion engine. Any torque nonuniformities which occur can be damped by this system by using either or both of the electric machine and flywheel masses which can be rotated in relation to each other even with the clutch disengaged. By activating the electric machine, a torque directed counter to the rotational nonuniformities is provided over a large frequency range. By tuning a two-mass flywheel formed by the flywheel masses to a frequency range in which large rotational nonuniformities occur, it is possible to relieve the load on the electric machine. Some of the rotational nonuniformities introduced by the internal combustion engine can be damped by the electric machine, and any remaining part can be damped by the mutually rotatable masses. Provision may also be made, in selected frequency ranges, to damp the torque nonuniformities introduced by the internal combustion engine solely by the mutually rotatable masses.
The incorporation of the primary flange as part of the rotor carrier carrying the rotor reduces the number of components and thereby produces a savings in costs, and reduces the required installation space occupied by this system.
In a preferred embodiment, the rotor includes a position transmitter for detecting the relative position of the rotor in relation to a fixed component which is preferably a stator of the electric machine.
A moving element of the position transmitter is permanently connected to the rotor carrier. The movement of the moving element is picked up by a detecting sensor system which is arranged for detecting movement of the moving element. The moving element of the position transmitter may be connected to the rotor carrier or to the primary flange using a recess and stud connection, a press fit or a welding connection.
In a further embodiment, the position transmitter generates at least two distinguishable output signals. The first output signal characterizes the relative position of rotor and stator and the second output signal characterizes the relative position of the crankshaft. The first output signal is preferably used for activating the electric machine, and the second output signal is preferably used to coordinate the activation of the electric machine with the ignition sequence of the internal combustion engine.
In yet a further embodiment, a cover plate is permanently fixed to the primary flange to form an axial edge. The cover plate includes a profile connected to a radial outer bounding edge of the cover plate. Movement of the profile is picked up by an associated sensor system when an assembly including the cover plate, primary flange and rotor is rotated. The profile may comprise segments which, together with the sensor system, form an incremental encoder. The profile preferably has a significant point along the circumference of the cover plate so that the angular position of the crankshaft is defined uniquely by the profile. Since the cover plate, primary flange and rotor are connected to the crankshaft, the significant point of the cover plate may be used to detect a crankshaft position. The detected crankshaft position may be used, for example, for activating the internal combustion engine. In this design of the sensor system, it is advantageous that the profile is formed in or on a cover plate which is provided to form an axial edge for the clutch arrangement. Thus, no separate component is needed for position detection, which has an advantageous effect on the production costs. This arrangement, comprising cover plate and associated sensor system, may also be provided in a drive arrangement having a clutch system without an electric motor.
The various features of novelty which characterize the invention are pointed out with particularity in th
Bartels Ernst
Bauch-Panetzky Dieter
Carlson Cora
Forster Bernd
Ochs Martin
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
Mullins Burton
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