Clutch Disc

Cushion spring

The lower part of the illustration shows the four most common types of facing springs. The facing springs lie between the clutch facings. They ensure gentle clutch engagement and hence smooth take up of drive. The pressure plate of the clutch must at first press the clutch plate against the flywheel, acting against the spring load of the facing springs. As this load builds up slowly and draws out the engagement process, the transmission speed can be adjusted to the engine speed with a delay by the flexing of the plates.

Besides smooth take off, good wear resistance, a better wear pattern and, a more uniform heat distribution are further advantages of the facing springs. We basically distinguish between four types of facing cushion spring systems (from left to right).

Single segment cushion spring

Single segment cushion spring, in which the facings on both sides are riveted to thin, bowed segments that in turn are riveted to the drive disc. The advantages are the small flywheel effect of the disc and the easier operation of the cushioning.

With a dual segment cushion spring

With a dual segment cushion spring, the facings are riveted to two segments lying on top of one another and acting in opposite directions. As with single segment cushion spring, the segments are riveted at the drive disc. The advantage of better cushioning and better utilization of the available cushion space is off set by the disadvantages of a greater flywheel effect and a higher price.

Multi-plate cushion spring

Multi-plate cushion spring is the most common version. The carrier plate of the facings is slotted and corrugated at the outer edge, where the facing lies. It functions in essentially the same way as the single segment cushion spring and is primarily used where there is no room for riveting the single segments to the carrier plate. With more heavily stressed clutch plates, the comparatively thin carrier plate in the area of the torsion damper must be reinforced by a second counterplate.

Intermediate cushion plate spring

Intermediate cushion plate spring is generally used for heavy commercial vehicles. The segment-like, corrugated panels are riveted on one side of the carrier plate that is extended to the outer edge. They therefore act only along one direction. A disadvantage is the large flywheel effect of the disc.