Torsional vibration damper
View Patent ↗A torsional vibration damper, particularly for use between the engine and the transmission of the power train in a motor vehicle, including two flywheels rotatable relative to each other against the opposition of a first energy storing device employing, for example, one or more coil springs and a second energy storing device, which is carried by one of the flywheels, which operates in parallel with the first energy storing device and which opposes rotation of the two flywheels relative to each other. In order to isolate the irregularities of movement of the first flywheel (such as vibrations which develop while the engine is in operation) from the second flywheel, the second energy storing device (such as a snap spring or a set of diaphragm springs) is coupled to the flywheels in such a way that the second flywheel develops a degressive action only when the first flywheel is caused to move through relatively small angles (especially between 1° and 10°) but not when the angles are larger (especially larger than 10°).
1. A torsional vibration damper comprising:
a prime mover having a rotary output element;
a first mass non-rotatably connectable with the rotary output element, the first mass including a primary flywheel of a split flywheel;
a second mass rotatable relative to the first mass, the second mass including a secondary flywheel of the split flvwheel;
a first energy storing device operating between the first and second masses;
a second energy storing device operating between the first and second masses in parallel with the first energy storing device and with freedom of rotation relative to the first energy storing device; and
a connection disposed between the second energy storing device and the first and second masses and arranged to develop a degressive effect in response to only angular displacements of the first and second masses relative to each other of not more than 10°;
the connection including a first element configured to fixedly connect the second energy storing device to one of the first and second masses, a securing element configured to secure the second energy storing device to the other of the first and second masses, the securing element including a freewheel arrangement.
2. The damper as recited in claim 1 , wherein the angular displacements are in the range of from 10° to 10°.
3. The damper as recited in claim 1 , wherein the prime mover includes an internal combustion engine in a motor vehicle.
4. The damper as recited in claim 1 , wherein the second energy storing device includes a resilient member having a degressive characteristic curve.
5. The damper as recited in claim 4 , wherein the resilient member includes a snap spring.
6. The damper as recited in claim 1 , wherein the freewheel arrangement includes two freewheels acting in opposite directions.
7. The damper as recited in claim 1 , wherein the freewheel arrangement includes a double-acting freewheel.
8. The damper as recited in claim 1 , wherein the second energy storing device includes a radially outer portion and the freewheel arrangement comprises at least one rolling element turnable relative to the radially outer portion of the second energy storing device.
9. The damper as recited in claim 8 , further comprising a guide channel provided on the radially outer portion of the second energy storing device and receiving the at least one rolling element, the channel being inclined relative to a circle having a center on a common axis of the masses.
10. The damper as recited in claim 9 , further comprising a guide arrangement having a pair of sidewalls flanking the channel.
11. The damper as recited in claim 10 , wherein the sidewalls are at least substantially parallel to each other.
12. The damper as recited in claim 11 , wherein the channel has a predetenriined width and the sidewalls have end portions spaced apart form each other less than the predetermined width.
13. The damper as recited in claim 10 , further comprising an annular roof-shaped connector overlying a radially outermost portion of the channel between the sidewalls.
14. The damper as recited in claim 10 , further comprising friction linings provided in the channel and arranged to be clamped between the guide arrangement and one of the first and second masses as a function of the condition of the second energy storing device.
15. The damper as recited in claim 14 , wherein the one of the first and second masses is the first mass.