Self-adjusting Clutch
Self-adjusting Clutch Construction and Operation
| Item | Description |
|---|---|
| A | Cross-section of a self-adjusting clutch |
| B | Schematic representation of the diaphragm spring forces |
| a | Forces in equilibrium |
| b | Operating force of the clutch is higher than the sensing diaphragm spring |
| c | Forces in equilibrium after the outward turn |
| 1 | Compression spring |
| 2 | Ramp ring |
| 3 | Clutch housing |
| 4 | Sensing diaphragm spring |
| 5 | Clutch disc |
| 6 | Diaphragm spring |
| 7 | Studs |
| 8 | Force of the sensing diaphragm spring |
| 9 | Operating force |
| 10 | Increased operating force because of wear |
Part A of the illustration shows a cross-section through a self-adjusting clutch.
A key difference to conventional clutches is that the diaphragm spring is not riveted to the clutch housing, but supported through a sensing diaphragm spring.
The diaphragm spring is a floating fit on the studs. The ramp ring and pressure spring are shown vertically in illustration A for clarity. The ramp ring and pressure spring are actually installed in the engine running direction.
As long as the operating force is less than or equal to the force of the sensing diaphragm spring, the diaphragm spring remains in its original position (illustration B, diagram a). When outward turning of the diaphragm spring tongues becomes necessary because of wear, higher operating force must be applied.
The operating force and the sensing diaphragm spring force are no longer in equilibrium. The diaphragm spring pushes the sensing diaphragm spring back (illustration B, diagram b). There is a gap between the diaphragm spring and the ramp ring.
The pressure spring displaces the ramp ring, and the gap is closed again. The diaphragm spring and the sensing diaphragm spring take up a new position on the studs. The diaphragm spring tongues move from their outward angle back into their original position (illustration B, diagram c).
Ramp Ring Construction
| Item | Description |
|---|---|
| 1 | Compression springs |
| 2 | Ramp ring |
| 3 | Ramp |
| 4 | Clutch housing |
The illustration shows the layout of the ramp ring.
The compression springs turn the ramp ring counterclockwise (CCW). The ramp ring is shown raised from its normal position for clarity.