A torsional detuner for dampening vibrations developed in an internal combustion engine having a crankshaft, a flywheel connected to the crankshaft and a transmission assembly coupled to the flywheel. The detuner includes a planar body mounted to the flywheel and having a central hub, a peripheral rim and a plurality of elastically deformable members connecting the hub to the rim. The deformable members extend outward from the hub to the rim in an outwardly radial spiral. Advantageously, vibrations developed in the engine are dampened by the relative rotation between the hub and rim.

TECHNICAL FIELD

The present invention relates to vibration control. More specifically, the invention relates to a torsional detuner or damper for use in a powertrain of a motor vehicle to dampen vibrations developed in the engine of the powertrain.

BACKGROUND

Torsional detuners or dampers have been used for many years in motor vehicles and are most often disposed between an engine, such as an internal combustion engine, and a transmission. The torsional detuners are typically connected to the flywheel of the engine and the input shaft of the transmission. A torsional detuner operates to reduce or eliminate vibrations that have developed in the crankshaft of the engine. The explosive forces acting on the pistons typically create these vibrations, which thereafter propagate through the crankshaft. At certain engine speeds, the vibration is more noticeable and can be irritating to an operator and, over time, such vibrations may damage the crankshaft itself.

Conventional vibration dampening devices employ detuners having energy storing elements. Typically, these energy storing elements are located on the periphery of the flywheel and include coil springs or a rubber member. Additional storage elements act in an axial direction, relative to the rotation of the flywheel, and cooperate with friction pads or linings to produce friction hysteresis.

While conventional vibration detuners achieve their intended purpose, problems still exist. For example, there are space constraints for packaging the torsional detuners. Further, conventional rubber detuners have a high internal hysteresis that can cause detuner failure due to heat. Moreover, the rubber used in conventional detuners becomes stiffer over time, and the increased stiffness, combined with high operating frequencies, can lead to transmission failure. In addition, it is well known that the compression spring-type detuners used today have inherent wear problems that cause premature failure.

Therefore, a need exists for a vibration detuner that is easily packaged, and withstands the heat and vibration that exists in the powertrain environment. The new improved detuner design should be highly space efficient, easily assembled to the driveline, have a low internal hysteresis and a substantially constant spring rate over time.

SUMMARY

In overcoming the above and other drawbacks and limitations of the conventional art, the present invention provides a device for dampening vibrations developed in a powertrain of a motor vehicle. The powertrain includes an internal combustion engine having a crankshaft connected to a plurality of pistons that are configured for reciprocal movement within the engine. An engine output shaft connects the crankshaft with a flywheel and the flywheel is coupled to a transmission. Through this coupling, torque developed in the engine is transferred to the transmission and to the ground engaging wheels or tracks of the motor vehicle.

In one aspect, the device of the present invention includes a planar body mounted to the flywheel. The planar body has a rim, a central hub, and a plurality of elastically deformable members connecting the rim to the central hub. The deformable members spiral radially outward from the hub to the rim. Further, a yoke is mounted to the central hub of the planar member for coupling to the input of the transmission. Through this construction, vibrations developed in the internal combustion engine are dampened by the relative rotation between the central hub and rim.

In another aspect of the present invention, the elastically deformable members are arcuate.

In yet another aspect, the elastically deformable members are formed from a plurality of steel plates.

In a further aspect of the present invention, the planar body is formed from a plurality of stacked steel plates.

In still another aspect of the present invention, planar body includes four elastically deformable members.

In one aspect of the present invention, a pair of guide pins are disposed in the planar body for aligning the planar body with the flywheel.

In another aspect, a plurality of apertures, each for receiving a fastener, are provided in the body to rotationally fix the planar body to the flywheel.

In yet another aspect of the present invention, the yoke has a plurality of apertures, each for receiving a fastener to rotationally fix the yoke to the driveline.

In a further aspect of the present invention, a powertrain is provided having an internal combustion engine, a transmission and a device disposed between the engine and the transmission for dampening vibrations developed in the engine. The engine includes a crankshaft and a flywheel connected to the crankshaft. The device itself is mounted to the flywheel and has a planar body with a peripheral rim, a central hub and a plurality of elastically deformable members connecting the peripheral rim to the central hub. A yoke is mounted to the central hub and to a driveline of the transmission assembly, whereby vibrations developed in the internal combustion engine are dampened by the relative rotation between the central hub and peripheral rim.

DESCRIPTION

Referring now toFIG. 1, a perspective view of a powertrain10incorporating a torsional detuner device12is illustrated, in accordance with the principles of the present invention. The powertrain10generally includes an internal combustion engine14, which may be a gas engine, a diesel engine or the like, coupled to a transmission assembly16. Generally, the internal combustion engine14has a plurality of pistons that are configured for reciprocal movement within corresponding combustion cylinders. Further, a crankshaft (not shown), coupled to the pistons, as is conventionally known, is rotated in response to the reciprocal motion of the plurality of pistons. The crankshaft is further coupled to a flywheel18and, thus, rotates the flywheel18. The flywheel18is coupled to the torsional detuner12and the torsional detuner12, in turn, transfers the rotational output developed by the engine14and flywheel18to the transmission assembly16through a transmission input shaft20(seen inFIG. 4). As will be described in further detail below, the torsional detuner12is configured to dampen vibrations propagated in the crankshaft of the engine14to prevent, or greatly reduce, the transfer of these vibrations to the transmission assembly16.

Referring now toFIGS. 2 and 3, perspective views of opposing sides of the torsional detuner12are illustrated therein. The detuner12is generally a circular, planar body having a central hub22, a peripheral rim24and a series of elastically deformable members26,27,28,29connecting the hub22to the rim24. In the illustrated embodiment, four members26,27,28,29are shown, it being understood that a fewer or greater number of members could be provided. The members26,27,28,29emanate from the hub22in an outwardly radial spiral configuration. Thus, between each of the members26,27,28,29is a slot30,31,32,33that similarly emanates in an outwardly radial spiral configuration.

The central hub22further includes a plurality of mounting apertures34(only some of which are labeled in the Figures) for mounting the torsional detuner to the transmission input shaft20. The hub22additionally includes a pair of guide pin apertures36for aligning a yoke38within a central aperture39in the hub22. More specifically, a pair of guide pins40, press-fitted into the yoke38cooperate with the guide pin apertures36to align the yoke38such that yoke mounting apertures42align with the mounting apertures34the hub22. Once the alignment of the mounting apertures34and42is achieved, a fastener44, such as a screw, bolt, rivet or pin, may be passed through the yoke38and hub22of the torsional detuner12to mount the detuner12to the transmission input shaft20. In order to mount the detuner12to the transmission input shaft20, a collar46having one end48in spline engagement with the input shaft20and an opposing end50in a flanged engagement with the detuner12is illustrated inFIG. 4.

The torsional detuner12further includes flywheel alignment pins52that are pressed fit into apertures on the peripheral rim24of the torsional detuner12. The flywheel alignment pins52cooperate with guide apertures (not shown) disposed in the flywheel18to assist in the alignment of flywheel mounting apertures54(not shown) disposed along the perimeter of torsional detuner12with mounting apertures disposed along the perimeter of the flywheel18. Fasteners56, such as screws, bolts, rivets, pins or similar devices extended through these mounting apertures54are used to fasten the torsional detuner12to the flywheel18.

In a preferred embodiment, each of the members26,27,28,29are configured to deform elastically when the detuner12is rotated by the flywheel18. The elastic deformation in members26,27,28,29as a result of relative rotational movement between the rim24and the central hub22, and therefore the flywheel18and the transmission input shaft20. In the illustrated embodiment, the members26,27,28,29are unitarily formed with the central hub22and peripheral rim24. However, in an alternate construction, the members may be separately formed and connected to the hub22and rim24.

As shown inFIG. 4, the torsional detuner12is formed as a stack58of plates60disposed adjacent each other. Each of the plates60is similarly shaped and, when stacked adjacent each other, cooperate to define the various features (hub22, rim24, members26-29, etc.) of the detuner12. Preferably, five to fourteen plates60of spring steel are utilized to form the stack58. However, the present invention contemplates a greater or lesser number of plates60and other materials, such as but not limited to, composites materials formed of polymers, ceramics and fibers.