Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
2000-10-06
2004-04-27
Browne, Lynne H. (Department: 3679)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C192S208000
Reexamination Certificate
active
06726569
ABSTRACT:
BACKGROUND AND SUMMARY OF THE INVENTIONS
The invention relates to a divided flywheel consisting of a primary flywheel mass connected secured against rotation with the drive shaft of an internal combustion engine, and a secondary flywheel mass wherein the two flywheel masses are mounted one on the other and able to rotate opposite one another relatively against the action of a damping device and the primary flywheel mass supports on its radially outer circumference a rotor of an electric machine.
A damping device with an integrated electric machine whose rotor is attached to the external circumference of the flywheel is known from DE OS 30 13 424. Devices of this kind are mainly used for starting up the internal combustion engine and for producing power in an electric machine as well as hybrid drives.
With one design mentioned at the beginning a torsional vibration damper is provided between the flywheel and gear input shaft and only dampens torsional vibrations coming from the internal combustion engine when the clutch is engaged.
Furthermore these devices have their own torsional vibration forms which lie in the region of the used speed band of the internal combustion engines and thus create loss of comfort in the drive train.
Divided flywheels which do not have these faults are adequately known—such as for example from DE 36 10 127 C2—without a rotor.
Divided flywheels of this kind are mainly filled with grease or oil and have the drawback that increased amounts of heat supplied through blind performances of the electric machine through the rotor, and thus raised operating temperatures, cause a severely fluctuating damping behaviour and/or dilution or liquefying of the oil or grease.
The object of the present invention is therefore to provide a damping device for a device having an electric machine rotating coaxially about the axis of rotation of the internal combustion engine, which has a high damping comfort over the entire speed range with simultaneous stability in respect of the temperature fluctuations which are introduced through the electric machine, and which can be housed in an installation space provided axially and radially by the electric machine. Furthermore this device is to be produced cost-effectively by using easily manufactured individual parts and is to be simple to assemble.
The flywheel according to the invention having the rotor attached to the primary flywheel disc is in active electric connection by its rotor with the stator of the electric machine which is connected directly or indirectly to the motor housing and/or to the gearbox housing.
The flywheel according to the invention having a rotor attached to the primary flywheel disc is in electric connection by its rotor with the stator of the electric machine which is connected directly or indirectly to the motor housing and/or to the gearbox housing.
According to the present invention this is achieved in that a divided flywheel is proposed consisting of a primary flywheel mass connected secured against rotation to the drive shaft of an internal combustion engine and of a secondary flywheel mass, wherein the flywheel masses are mounted one on the other and able to rotate relative to each other against the action of a damping device, and that the primary flywheel mass consists at least of a flywheel disc connected to the drive shaft and having on its outer circumference an axially aligned ring-shaped platform on which the rotor of an electric machine is fixed, with the secondary flywheel mass having a flywheel disc which supports a clutch for coupling and uncoupling a following unit in the force flow.
Through this bell-shaped impression of the primary flywheel disc which can be produced by cold reshaping technology an assembly is formed which supports the rotor substantially freely by holding the rotor on its axially extending external circumference without forming thermal bridges for a heat flow from the rotor to the damping device. The result of this is that the divided flywheel has a thermal barrier between the rotor and damping device, i.e. the damping device is thermally uncoupled from the rotor.
It is thereby expedient if the thermal uncoupling takes place through an air gap formed between the radially outer circumference of the damping device and the axially extending platform holding the rotor on the outer circumference of the primary flywheel disc. Also the system of air gaps between the primary and/or secondary flywheel disc on one side and the damping device on the other can produce a cooling action, particularly when the air gaps are automatically ventilated through the rotation of the flywheel during operation.
For this purpose in order to ventilate these air gaps and thus the damping device a sufficient number of air slits can be provided in one or both flywheel discs where they are spread out round a circumference whose diameter is preferably the diameter of the circumference of the chamber formed by the side parts of a flywheel disc and holding the energy accumulator of the damping device, and thus the grease or oil introduced for lubrication and when using hydraulic systems—for example according to DE 36 10 127 C2—for damping is cooled and thus produces ideal constant damping conditions.
In further embodiments insulating materials of any kind, such as for example ceramic and/or plastics can be provided between the rotor and damping device to produce a thermal insulation between the damping device and rotor.
Likewise the fastening device for the rotor on the secondary flywheel disc and/or the rotor can have on the circumferential side a groove-shaped profile, for example axially running grooves which reduces the effective bearing surface of the rotor and thus creates a thermal insulating effect.
This profile can be imprinted so that the rotation of the flywheel produces an automatic ventilation for example through air guide plates or through a suitably shaped fastening device.
According to the invention the rotor or a device enclosing same for fixing purposes can be connected with keyed engagement by an internal profiled section to the ring surface having an external profiled section wherein the internal profile has internal gearing with at least one tooth and the external profile has external gearing with at least one tooth gap, more advantageously however gearing with evenly spaced teeth and tooth gaps is. the preferred means.
A further variation is the use of at least one groove and one spring complementary therewith as the external and internal profile producing the positive locking engagement.
In order to secure the axial strength in addition axial welding is provided between the ring face and rotor which in a corresponding design can also alone form the connection.
To this end a flat surface welding is carried out radially on the external and internal circumferences of the ring face and rotor, for example by means of the impulse welding process. Furthermore the rotor can be pressed and/or staked onto the ring face. Riveting is likewise recommended, for example between a further flange-like radially outwardly extending shaped area which adjoins the axial path of the platform and can serve at the same time as an axial stop for the rotor whereby rivets in the axial direction over a preset circumference can produce the connection with the rotor.
A further inventive idea proposes dividing the primary flywheel disc into two parts, namely into a radially outer support part relative to the circle of holes for fixing the flywheel on the drive shaft, and which holds the rotor, and into a radially inner bearing pin forming the bearing for the secondary flywheel disc.
The advantage here is the easier production of two less complex disc parts Both parts are housed and centred on centring noses which can be attached to the drive shaft or a component part connected therewith wherein a sequential build-up of several discs can be formed in the axial direction in addition a disc can be added forming the input part of the damping device and which can likewise be attached on the drive shaft with the
Kirschner Martin
Ronner Gerhard
Seidl Holger
Browne Lynne H.
LuK Lamellen und Kupplungsbau Beteiligungs KG
Thompson Kenneth
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