The most important clutch elements
1 - driven disk; 2 - clutch pressure plate; 3 - clutch release bearing; 4 - clutch drive cable; 5 - clutch clearance adjustment mechanism; 6 - clutch pedal.
Only the clutch makes it possible to accelerate without jerks, since the driving force of the engine is transferred smoothly through the gearbox to the drive wheels. Shifting a manual transmission would hardly be possible without a clutch.
Clutch function
The transmission of the driving force of the engine to the gearbox occurs through friction. To do this, 3 discs are pressed against each other, with one disc «clamped» between 2 others. Clutch elements include:
- The flywheel in the engine serves as a bearing surface;
- The clutch pressure plate acts as a second bearing surface that presses against the flywheel.
- Between them is a driven disk. It is mounted on the input shaft of the gearbox.
- In addition, there is also a clutch release bearing.
When you press the clutch pedal with your foot, the clutch release lever with the clutch release fork is actuated through the clutch cable. The clutch release fork presses on the clutch release bearing located on the shaft and presses it into (cut like a cake) clutch pressure plate diaphragm spring. With a strong foot pressure on the clutch pedal, the clutch release bearing overcomes the elasticity of the Belleville spring, the pressure plate is unloaded and moves back when the pedal is fully depressed. At the same time, the driven disk rotates freely in the resulting space, that is, the clutch is turned off. When the clutch is engaged, the disc spring of the pressure plate presses the driven plate against the engine flywheel. For a soft transfer of force, all this should happen smoothly, without jerks. The bearing surfaces rub against each other for some time until the friction becomes so strong that it transfers all the engine power completely to the gearbox.
Clutch life
Each engagement of the clutch leads to friction of the coating of the clutch disc with the supporting surfaces and their mutual heating. The clutch wears out especially strongly when starting off at high engine speeds (racing start), accelerating in 2nd gear, when driving at intersections in 2nd or 3rd gear with the clutch pedal partially depressed, or when immediately entering a hill (ramp) using the clutch pedal and gas pedal.
Should I disengage the clutch at an intersection?
It is quite common to wait for a green traffic light with 1st gear engaged and the clutch pedal depressed. Some are afraid of not being able to turn on the transmission in time if the green light turns on. Although this does not cause immediate or immediately noticeable damage, but disengaging the clutch loads the clutch release bearing and thereby increases its wear. The more often this happens, the sooner the bearing wears out.
When you press the clutch pedal with your foot, the clutch cable (2) actuates the clutch release fork (1) and shifts to «X» (distance), equal to approximately 28 mm, otherwise the driven disk will not be released from contact with the flywheel and clutch pressure plate. If this value does not correspond to the set value, then it is necessary to check the clutch adjustment mechanism or the clutch release fork for wear.