Rotary shafts – gudgeons – housings – and flexible couplings for ro – Torque transmitted via flexible element – Coil spring
Reexamination Certificate
1994-08-18
2001-09-04
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Torque transmitted via flexible element
Coil spring
C192S11000B
Reexamination Certificate
active
06283864
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to improvements in assemblies which can be utilized to take up and to compensate for shocks which develop as a result of fluctuations in the rotational speed of the output element of an internal combustion engine. More particularly, the invention relates to improvements in assemblies which can be used in motor vehicles between the internal combustion engine and the input element of a change-speed transmission to blunt the effects of shocks which develop as a result of fluctuations in the transfer of torque between the engine and the transmission. Still more particularly, the invention relates to improvements in assemblies of the type wherein a first rotary unit receives torque from the engine, a second rotary unit transmits torque to the transmission, the two units are coaxial with and rotatable within limits relative to each other, and the means for transmitting torque between the two units comprises a damper of vibrations and of other undesirable movements. As a rule, or at least in many instances, the damper comprises resilient elements which act in the circumferential direction of the two units and one or more friction generating devices.
Assemblies of the just outlined character are disclosed, for example, in German Offenlegungsschrift No. 29 26 012. The damping action between the two rotary units which can turn within limits with reference to one another is provided by energy storing devices in the form of coil springs and by a friction generating device which is installed to operate in parallel with the coil springs. The coil springs offer a progressively increasing resistance to further angular displacements of the two units with reference to each other from a starting or neutral position. In other words, the coil springs (or at least some of the coil springs) will yield in response to the exertion of a relatively small force when one of the units begins to move from the neutral position, and the resistance increases progressively as the angular displacement of the one unit relative to the other unit increases. The resistance which the friction generating device offers to rotation of the one unit relative to the other unit remains at least substantially constant.
Assemblies embodying the just described damper are designed to operate in such a way that their critical fundamental frequency, namely the critical RPM of the driven and driving parts, develops at a resonance which is below the ignition cycle frequency when the RPM of the engine is at a minimum value, namely the lowest RPM at which the engine is still running. However, when an internal combustion engine is started or turned off, it frequently takes a rather long period of time during which the RPM is within the critical range so that the vibration amplitude of the two units which are rotatable relative to each other increases still further as a result of excitation within such range of rotational speeds. The result is that the resilient elements of the damper between the two units undergo maximum deformation and enable rotation limiting stops on the two units to move into actual contact with each other. Under such circumstances, i.e., when the two stops actually abut against each other, the damper is totally ineffective in that it cannot compensate for or take up any shocks. Therefore, the vehicle which embodies such an assembly is vulnerable to shocks which develop while the two stops are in actual contact with one another due to the absence of any damping or shock absorbing action. This not only affects the comfort of the occupant or occupants of the motor vehicle but also generates pronounced noise. Still further, the shafts, bearings and certain other parts of the engine and transmission in the motor vehicle are likely to undergo substantial damage.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved torsion damping assembly which is particularly effective during starting and/or stoppage of the engine in a motor vehicle.
Another object of the invention is to provide an assembly which can ensure adequate damping of undesirable movements and/or forces during each and every stage of the operation of a motor vehicle and is also highly effective during those stages when the aforediscussed and other conventional torsion damping assemblies are incapable of providing an adequate damping action.
A further object of the invention is to provide a simple, compact and inexpensive torsion damping assembly which can be incorporated in existing motor vehicles in lieu of presently known assemblies as a superior substitute therefor.
A further object of the invention is to provide a torsion damping assembly which can be used to compensate for shocks and variations of torque with a higher degree of efficiency, reliability and predictability than heretofore known assemblies.
An additional object of the invention is to provide a novel and improved method of damping vibrations and/or other undesirable movements between two coaxial parts of a flywheel in a motor vehicle.
A further object of the invention is to provide a novel and improved mode of establishing a torque transmitting connection between the internal combustion engine and the change-speed transmission of a motor vehicle.
Still another object of the invention is to provide novel and improved damper means for use in the above outlined assembly.
Another object of the invention is to provide novel and improved flywheels for use in the torsion damping assembly of the above outlined character.
The invention resides in the provision of an assembly which serves to take up and compensate for torque-induced shocks, especially to take up and compensate for torque which is transmitted between the internal combustion engine and the change-speed transmission of a motor vehicle. The improved assembly comprises coaxial first and second units which are mounted for limited angular movements with reference to each other. The first unit normally receives torque from the engine and the second unit serves to normally transmit torque to the input element of the change-speed transmission. The assembly further comprises a damper which is disposed between the two units and operates to yieldably resist angular movements of the two units relative to each other, and at least one slip clutch which is interposed between the two units and includes opposing means for yieldably resisting a predetermined stage of angular movement of the two units with reference to each other. The damper can comprise a plurality of coil springs or other suitable energy storing elements which act in the circumferential direction of the two units and/or one or more friction generating devices which are interposed between the two units and can be arranged to oppose each and every increment of angular movement of the two units with reference to one another. The damper and the slip clutch preferably operate in series (i.e., they become effective one after the other), and the slip clutch can constitute a multi-stage slip clutch. To this end, the slip clutch can comprise a plurality of stages each of which serves to offer a different resistance to rotation of the two units relative to each other in different angular positions of such units relative to each other. The opposing means of the slip clutch can comprise resilient means in the form of diaphragm springs, leaf springs, coil springs and/or a combination of two or more different types of springs. The resilient means can include one or more springs which are effective to oppose rotation of the two units relative to each other in at least one end portion of the aforementioned stage of angular movement during which the slip clutch is effective.
The first and second units preferably comprise first and second flywheels, and the damper as well as the slip clutch are installed to yieldably resist rotation of the flywheels with reference to each other. In accordance with one presently preferred embodiment, the slip clutch comprises a first component which extends substantially radial
Friedmann Oswald
Reik Wolfgang
Binda Greg
Browne Lynne H.
Darby & Darby
LuK Lamaellen und Kupplungsbau GmbH
LandOfFree
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