184000304 - INTRODUCTION - CLUTCH

CONSTRUCTION FEATURES

The clutch is the dry, single plate type with a thrust bearing always in contact with the flexible coupling spring.The driven plate is drven by pressure exerted by a diaphram spring. The clutch release is activated through the hydrauilc system operated by the pedal.

COMPOSITION

The system consists of:

  • a clutch pump (master cylinder) (2), which has the task of compressing the fluid and is fixed to the pedals;
  • a connecting pipe (3) between the pump and the clutch operating cylinder;
  • a clutch operating cylinder (4) fixed to the gearbox;
  • linkage (5) operating the thrust bearing;
  • a thrust bearing (6);
  • a clutch drip tray with diaphragm springs (7);
  • a clutch plate (8);
  • a fluid reservoir (1) shared with the braking system.
1, Brake/clutch fluid reservoir2, Clutch pump3, Connecting pipe between pump and cylinder4, Clutch operating cylinder5, Linkage6, Thrust bearing7, Diaphragm spring8, Clutch plate

OPERATION

The pump (2), operated by the clutch pedal, pressurizes the hydraulic circuit and activates the clutch operating cylinder (4).The latter acts on the operating linkage (5), which 'pulls' the thrust bearing (3), overcoming the action of the pressure plate springs (7).This action uncouples the clutch plate (8) from the flywheel.When the pedal is released, the action of the diaphragm springs (7) returns the mechanism to the original position. For the 1.9 Multijet version, the clutch release system is under coaxial hydraulic control.With this type of control, there is no clutch release shaft, relevant bushes, external clutch release lever and the clutch cylinder (actuator).The system is defined as co-axial because the release actuator consists of an aluminium ring cylinder fitted inside the bell housing between the gearbox and the clutch mechanisms in a position which is co-axial in relation to the main shaft.

The advantage of the system compared with traditional systems is that there are no kinematic couplings which results in improved reliability and functionality and make the system easy to maintain. The system has the following features:

  • constant adjustment of the clutch pedal height;
  • effort applied to the pedal constant over a period of time;
  • elimination of clutch pedal return difficulties;
  • reduction in the noise and vibrations from the pedal through the action of a damper on the cylinder fluid pipe.
The pipe is connected to the actuator by a rapid connector with a bleed valve incorporated.The absence of the traditional system idler crank mechanism, the adoption of a clutch pump with a plastic casing and piston and the use of plastics for the construction of the pedal assembly has also made it possible to greatly reduce the noise and the overall weight of the system.
1. Oil inlet pipe2. Expansion chamber3. Piston4. Thrust bearing5. Threaded locking flange6. O-ring7. Wear-resistant pads8. Rubber gaiters9. Spring10. Guide pipeThe release of the clutch takes place through the action of the clutch pump which sends fluid under pressure, through the pipe (1), to the expansion chamber (2). The pressure of the fluid causes the movement of the piston (3) which slides in the guide tube (10) by means of Teflon anti-wear pads (7). The piston is in one piece with the thrust bearing (4) which presses against the pressure plate springs disconnecting the clutch. When the pressure of the fluid ceases, the actuator returns to the rest position through the action of the pressure plate springs.An oil seal (5) and O-ring (6) prevent gearbox fluid leaking into the clutch housing.There are rubber gaiter (8), kept in position by a spring (9), as protection against the entry of outside agents.