Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-08-17
2001-09-25
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C180S165000, C310S078000
Reexamination Certificate
active
06294854
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates motor vehicles, and more particularly to a drive arrangement for a motor vehicle having an internal combustion engine.
2. Description of the Related Art
DE 43 23 601 A1 has already disclosed a drive arrangement for a motor vehicle, having an internal combustion engine, a clutch and an electric machine. As an output, the internal combustion engine has a crankshaft which can be connected via an interposed clutch to an output drive shaft which, at the same time, is a gearbox input shaft. The clutch is at least partially arranged radially inside an electric machine. The electric machine has a stator permanently connected to the housing of the engine and a rotor that is connected to the output drive shaft in a rotationally fixed manner connected with the interposition of torsional vibration dampers. It is also possible for pressure plates provided in the clutch to be connected to the output drive shaft in a rotationally fixed manner via torsional vibration dampers. The disadvantage is that the coupling between the rotor and gearbox input shaft, apart from the twisting angle of the torsional vibration damper, is of rigid design. As a result, the electric motor is capable of exerting an influence only on the rotor or gearbox input shaft.
DE 196 18 865 A1 has disclosed a drive arrangement for a motor vehicle, which has an electric machine arranged between the internal combustion engine and gearbox. This electric machine comprises a stator that is permanently connected to the housing of the engine, and a rotor that is permanently connected to the crankshaft. By means of a friction clutch arranged between the electric machine and gearbox, it is possible to uncouple the internal combustion engine from the gearbox in order to carry out a shifting operation.
A disadvantage with this arrangement is that during any acceleration of the internal combustion engine, the rotor also has to be accelerated as part of the flywheel mass, resulting in a reduction in the maximum acceleration of the crankshaft. As a result, there is associated inertia of the drive train.
SUMMARY OF THE INVENTION
It is an object of the invention is to provide a drive arrangement with improved vibration damping. It is another object of the invention to widen the field of use of the electric machine and provide a drive arrangement enabling an increased reaction speed of the motor vehicle.
Torque fluctuations introduced by the internal combustion engine depend on its ignition frequency or rotational speed. As a result of the measure that the rotor can be coupled to the drive train, the clutch and the output drive shaft by means of a switchable interlocking device, the inertial mass of the drive train, which acts as a flywheel mass, can be varied by coupling or uncoupling the rotor, for example as a function of the rotational speed or of the desired acceleration of the motor vehicle. If, on account of the driving situation, only slight torque fluctuations are expected, a low inertial mass is adequate as the flywheel mass in order to damp the torque fluctuations. The drive arrangement, and hence the motor vehicle, have a high reaction speed on account of the low inertial mass that acts as a flywheel and therefore as the mass to be accelerated during a desired acceleration operation. If, on account of the operating situation of the motor vehicle, greater torque fluctuations are to be expected, the inertial mass can be increased by coupling the rotor to the drive train by means of switching the interlocking device. It is preferable for the rotor to be accelerated to the rotational speed of the drive train by activating the electric machine, and to be coupled to the drive train when the rotational speeds are equal or virtually equal. Once the rotor is coupled, then the activation of the electric machine may be discontinued, which means that the rotor is used with the function of a passive absorber. If required, the electric machine can be activated for the purpose of active vibration damping, by a torque opposed to the torque fluctuation being introduced into the drive train by the electric machine, such as disclosed, for example, by DE 32 30 607 A or EP 437 266 A2.
Furthermore, it has been shown to be advantageous to couple the rotor to the flywheel by means of the interlocking device. The rotor is preferably arranged coaxially with the flywheel assigned to the internal combustion engine. In order to provide a high moment of inertia, it is advantageous to provide an external rotor type as the electric machine which, because of the large radius, has a high moment of inertia. It is also preferable for a compact clutch to be arranged radially inside the electric machine as the clutch. It is also possible for other clutches, such as multi-plate clutches or wear-adjusting clutches to be provided. This drive arrangement is particularly compact and is especially suitable for use in passenger motor vehicles, in which the installation space is particularly tight. For use in utility motor vehicles, it may be advantageous to use a friction clutch having a large diameter, via which a high torque can be transmitted. There is generally more installation space available in utility motor vehicles, so that a parallel arrangement of electric machine and clutch is possible.
In another embodiment, a torsional vibration damper is interposed so as to couple the rotor to the drive train. This torsional vibration damper may comprise, for example, a spring element or else resilient dampers and associated stops. It has been shown to be advantageous to provide an adjustment mechanism for adjusting the position of rotor relative to the component to which the rotor can be coupled. By means of adjusting the relative position of rotor and the associated component of the drive train, the effectiveness and the working point of the torsional vibration damper is adjustable. As a result, when the rotor is coupled, the torsional vibration damping can be matched to the expected vibrations.
In a further embodiment, provision is made for the clutch to be provided with a rotationally operated clutch operator, which can be operatively connected to the electric machine. In order to disengage the clutch, the necessary rotational movement can be introduced by activating the electric machine. It is therefore possible for the electric machine to be used for active and passive vibration damping (particularly in operating situations in which severe vibration is to be expected), and to be provided for operating the clutch. The torque introduced by the internal combustion engine is preferably reduced before the clutch is disengaged. This is also associated with a reduction in the torque fluctuations, so that it is possible to dispense with any damping of the torque fluctuations by means of the electric machine.
In a further embodiment, provision is made for the rotor to be able to be coupled to the output drive shaft by means of an interlocking device. As a result, the output drive shaft, which is preferably at the same time the gearbox input shaft, can be accelerated by activating the electric machine. The possibility of accelerating or retarding the output drive shaft by means of the electric machine is particularly advantageous for the purpose of active synchronization during a shifting operation.
In yet a further embodiment, a selector device is provided whose selector position enables the rotor to be selectively coupled to the clutch operator or to the output drive shaft. If the rotor is connected to the clutch operator by the selector device, then the clutch can be operated by activating the electric machine. If, on the other hand, the rotor is coupled to the output drive shaft via the selector device, active synchronization and vibration damping can be provided by the electric machine. In a further embodiment, provision is made for the stator to be mounted by means of a bearing so that it can rotate with respect to a component fixed to the bodywork. The stator is assigned a locking device by mean
Grosspietsch Wolfgang
Kretzschmar Martin
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
Nguyen Tran
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