There have been two primary forms of clutch action in automobiles with transmissions that are manual over the years: hydraulic and mechanical. While almost all current motor vehicles employ a hydraulic clutch, many older cars have a mechanical or cable mechanisms.
Lets get started!
What is a Hydraulic Clutch?
The clutch disc of a hydraulic clutch is pushed by hydraulic fluid as opposed to a cable. It makes use of reservoir cylinders to control pressure in reaction to clutch pedal pressurization. The vast majority of automobiles produced after the 1990s feature hydraulic clutches.
Reputable manufacturers are increasingly utilizing hydraulic clutches in their commercial trucks due to their excellent performance and simplicity of use.
These clutches are widely used in various systems due to their unique features like auto-adjustment, self-lubrication, and minimal adjustment effort required.
How Does A Hydraulic Clutch Works?
Clutch action comprises two phases, which are engagement and disengagement. we’ll go further for more details regarding each of these stages.
clutch Disengagement: Clutch pedal compressing starts this part of the hydraulic clutch’s action. As a result, the master cylinder’s hydraulic piston pushes the hydraulic clutch fluid in the clutch reservoir.
Via the fluid-filled tube, this high-pressure fluid is sent to the slave cylinder, and it acts on the slave cylinder’s piston, so triggering the clutch release bearing and clutch fork.
By retracting the splined sleeves, the diaphragm spring—which is under pressure—pulls the pressure plate away from the flywheel. The quick and seamless gear shift is made possible by this power outage.
Clutch Engagement: After changing gears, the clutch pedal is let go. This will trigger the master and slave cylinders’ hydraulic pressure to decrease, initiating clutch engagement.
The diaphragm spring, fork, and bearing will then be released to return to their initial positions. Power transfer restarts when the friction surface makes contact with the flywheel and the clutch plate is under renewed pressure.
The hydraulic clutch mechanism is crucial in manual transmission motor vehicles, involving various components such as the clutch pedal, master cylinder, pressure pipe, slave cylinder, release fork, release bearing, diaphragm spring, pressure plate, splined sleeves, clutch plate, and flywheel.
The clutch pedal initiates the engagement process, while the master cylinder pressurizes clutch fluid when depressed. The pressure pipe transports hydraulic fluid at high pressure from the slave cylinder to the master cylinder, allowing the clutch to operate.
The slave cylinder’s release fork connects to the push piston rod of the slave cylinder, allowing hydraulic fluid from the master cylinder to enter the slave cylinder. The release fork works on the release bearing when the clutch pedal is pressed.
The diaphragm spring, mounted on the pressure plate, preserves pressure on the clutch plate with its semi-circular ‘C’ shape. The pressure plate maintains pressure on the friction plate, which is responsible for pressing the friction plate against the flywheel.
Splined sleeves are held under pressure by the pressure plate and are situated between the friction lining of the clutch plate and the plate. They allow the engine to be eliminated from the transmission by releasing the pressure plate.
The clutch plate, sandwiched between the pressure plate and flywheel, is lined with friction material to control power flow between the engine and transmission.
The flywheel uses the clutch plate to transmit power from the engine to the gearbox, breaking down when the clutch pedal is pressed down, ensuring smooth gear shifting.
Hydraulic clutches offer several advantages over mechanical clutches, such as faster reaction times, a smaller amount of effort required, and less wear and tear. They are self-lubricating and have low friction characteristics, requiring less maintenance.
They can be used by cable-operated systems without frequent cable wire lubrication, and there is no need for regular cable maintenance due to potential damage. Hydraulic clutches also last longer and are less likely to suffer unexpected cable failures.
However, hydraulic clutches have some disadvantages. They take up more room due to numerous parts and oil pipelines, and they can cause fluid leakage due to the continuous cycling of clutch fluid.
The slave cylinder may leak fluid due to hydraulic faults, damaging the clutch plate. The hydraulic pipe, made of metallic or plastic parts, may corrode over time, requiring periodic checks to prevent serious damage.
Additionally, clutch fluid may get contaminated with contaminants after extended usage, necessitating periodic fluid changes to maintain the reservoir’s fluid level and prevent component damage. Bleeding is a laborious process for hydraulic clutch repairs to release trapped air.
