Interrelated power delivery controls – including engine control – Plural engines – Electric engine
Reexamination Certificate
1999-09-29
2001-04-17
Estremsky, Sherry (Department: 3681)
Interrelated power delivery controls, including engine control
Plural engines
Electric engine
C477S008000, C477S012000, C192S025000
Reexamination Certificate
active
06217476
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a torque-transmitting device, particularly for motor vehicles, with a prime mover unit such as a combustion engine with a driving shaft, a speed-changing transmission with a transmission input shaft, and a hydraulic coupling device between the prime mover unit and the transmission, i.e., a fluid coupling such as a Föttinger coupling, or a hydrodynamic torque converter, consisting of at least a pump wheel connected to the torque-input side and a turbine wheel connected to the torque-output side, as well as in some cases a stator wheel interposed between the pump wheel and the turbine wheel, and at least one housing solidly connected to the pump wheel and containing the turbine wheel.
Devices of this kind have been known for a long time and have been optimized for a great variety of diverse tasks and requirements. In order to completely disengage the torque-transmitting unit from the prime mover unit, DE-OS 40 07 424 proposes the use of a mechanical clutch arranged outside of the housing between the prime mover unit and the torque-transmitting unit, where the mechanical clutch either comprises a separate piston housing for the hydraulic control of the clutch or requires the axial displacement of a housing shell for disengaging the clutch. Thus, the proposed solution requires more space in the axial direction and is expensive to implement.
OBJECT OF THE INVENTION
Therefore, the object of the present invention is to provide a torque-transmitting device that comprises a disconnecting clutch between the hydraulic coupling device (i.e., a fluid coupling or hydrodynamic torque converter) and the prime mover unit but requires neither appreciably more axial space nor additional external actuator means for the disconnecting clutch while at the same time offering the advantage of a simple and cost-effective design.
SUMMARY OF THE INVENTION
The invention is embodied in a torque-transmitting device comprising a prime mover unit such as a combustion engine with a driving shaft, a speed-changing transmission with a transmission input shaft, and a hydraulic coupling device between the prime mover unit and the transmission, i.e., a fluid coupling such as a Föttinger coupling, or a hydrodynamic torque converter, comprising at least a pump wheel connected to the torque-input side and a turbine wheel connected to the torque-output side, as well as in some cases a stator wheel interposed between the pump wheel and the turbine wheel, at least one housing solidly connected to the pump wheel and enclosing the turbine wheel, and also comprising at least one disconnecting clutch that is arranged inside the housing and serves to uncouple the housing from the prime mover unit.
Accordingly, the disconnecting clutch can be arranged in a space-saving manner immediately inside the housing and without the need for additional housing parts.
It is particularly advantageous to use the disconnecting clutch to uncouple the prime mover unit from the fluid coupling or torque converter with the speed-changing transmission because the two aggregates can be operated independently of each other. Thus, for example, an electric machine driving the torque converter can power the motor vehicle when the prime mover unit is uncoupled, or the prime mover unit can power only additional auxiliary aggregates without driving the torque-transmitting device.
In advantageous arrangements, the electric machine is rotationally locked to the housing, for example by means of toothed profiles, friction wheels, belt drives or chains; or the electric machine may be arranged immediately around the housing with the rotor being solidly attached to the housing so that it rotates together with the latter. Thus, the “stator” is mounted on and rotates with the housing of the electric machine i.e. has a non-rotatable connection to a component, e.g., to the housing or a supporting holder mounted on the housing, of either the prime mover unit or the speed-changing transmission. The latter may be, for example, an automatic step-shifting transmission, continuously variable transmission or the like.
The housing of the torque-transmitting device, particularly in combination with an attached rotor, represents the inertial mass for the prime mover unit. To increase the moment of inertia, the rotor can be equipped with an additional inertial mass that is preferably arranged between the prime mover unit and the torque-transmitting unit and preferably has a shape that conforms, but leaves a clearance, to the contour of the one half of the housing that faces towards the prime mover unit, to make optimum use of the available space.
An inventive embodiment of the disconnecting clutch may consist, e.g., of an axially movable piston with preferably at least one friction lining arranged near the outer perimeter by which the piston engages a corresponding friction surface on the housing or on a component connected to the housing; or the piston may comprise a pressure surface by which it acts against laminar clutch disks that are attached to the housing to form a frictional coupling. In an advantageous arrangement, the at least one friction lining can be mounted on a conically sloped, ring-shaped exterior part of the piston conforming to the conical shape of the one half of the housing facing towards the side of the prime mover unit. This allows the centrifugal effect of the rotating housing to generate greater amounts of contact pressure and to thereby increase the amount of torque that can be transmitted.
When the clutch is engaged, to transmit the torque from the driving shaft to the housing and thus to the pump wheel that is solidly attached to it, the piston according to the invention can be arranged around and rotationally locked to a connecting part of the driving shaft that extends into the housing. The connecting part is, e.g., centered on or in the driving shaft and non-rotatably connected to the latter through an axially flexible and rotationally stiff torque-transmitting sheet-metal plate, the connecting part being attached to the torque-transmitting sheet-metal plate through a radially oriented flange-like part. The connecting part can also be formed by the driving shaft itself.
It is further advantageous to actuate the piston by means of the pressure supplied by the existing oil pump that is used to run the transmission. A chamber is formed for this purpose between the housing wall on the prime mover side and the piston, which can be supplied with oil, e.g., via a bore through the transmission input shaft, thereby creating a positive pressure differential relative to the pressure in the housing. The pressure differential causes the piston to move axially in the direction towards the turbine wheel and thereby retracts the friction layers from the housing wall or opens a set of laminar disks, so that the clutch is disengaged. The axial travel of the piston can be induced, e.g., by means of a toothed profile on the connecting part, or the piston can be solidly attached to the connecting part via a ring-shaped intermediate part, the latter being axially movable. The axial travel can also be made to work against the force generated by leaf springs that are distributed over the perimeter and are connected to the piston at the ends facing towards the perimeter and at their opposite ends to a driving part, e.g., to the housing or the connecting part, or else to a part that has a force-transmitting relationship to the housing or the connecting part. The axial travel is compensated for by the intermediate part, which for this purpose may have a wave-shaped cross-section. The peaks and valleys of the waves can advantageously be arranged transverse to the radial direction of the ring.
It may furthermore be advantageous to provide the torque-transmitting device with a lockup clutch of an essentially known design in order to bypass the torque converter when the rpm of the prime mover unit exceeds a set, pre-determined rpm value and to conduct the torque flow directly from the housing to the transmission input shaft
Heck Thomas
Muller Bruno
Wagner Uwe
Darby & Darby
Estremsky Sherry
LuK Getriebe-Systeme GmbH
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