Vehicle Transmission and Brake Systems
Differential Systems
Differential
The differential system adapts the wheels in curves, ensuring stability and proper functioning. It includes the pinion, crown, planet gears, and satellites. Check for possible oil leaks, visually inspect the support joints, and check the pinion and crown for proper spacing.
Locking Differential
The locking differential automatically locks the differential.
Track Lock Differential
This differential is based on friction. Multiple friction discs are placed with a conventional differential: differential box, multi-clutch set, satellites, planet gears, and crown.
Ferguson Differential (Viscous Coupling)
This differential’s operation is based on the difference in angular velocity of the drive axles. When one wheel slips, the pressure on the discs increases, braking the wheel’s motion and transferring traction to the wheel with ground contact.
Torsen Differential
This automatic locking differential mechanically distributes drive force from 15% to 85% to both wheels.
Transfer Case
The transfer case is placed between the gearbox and the front and rear differentials to increase torque and change traction distribution as needed. It includes helical gears, primary and secondary shafts, and synchronized short and long gears for 2- and 4-wheel drive. Maintenance includes checking for oil leaks.
Transmission System
The transmission system transmits movement from the engine shaft to the wheels, allowing them to move on the ground.
AWD (All-Wheel Drive)
In AWD vehicles, the engine power is distributed to all four wheels, reducing the risk of skidding and increasing stability.
Driveshafts
Driveshafts transmit power from the gearbox to the differential, which then transmits the movement to the wheels.
Universal Joint
Universal joints allow for angular variations up to 25 degrees. They are often used in rear differentials.
Hook Joint
Hook joints are a variant of universal joints. The main difference is that the arms of the cross incorporate needle bearings to facilitate movement.
Brake System
The brake system can be defined as a circuit that transfers brake fluid from the pump to the brake components, including the wheel cylinders and brake calipers.
Tripod Joint
The tripod joint is a variant of the Hook joint. Its geometry allows for linear movement variation.
Constant Velocity Joint (CV Joint)
CV joints, also known as Rzeppa joints, are used in transmissions and allow for angular variations up to 60 degrees.
Wheel Bearings
Wheel bearings support the rotation of the wheels. They include tapered roller bearings, ball bearings, and needle bearings. Durability is affected by harsh braking, rapid changes in speed, oversized tires, and sharp cornering.
Brake Shield Breakdowns
Noise emitted by spinning balls can cause vibrations in the vehicle.
Braking System
The braking system’s mission is to stop the vehicle efficiently and safely at the driver’s will.
Braking Forces
Braking forces include the force applied by the driver on the pedal, the braking force on the brake pads, the friction force between the tire and the ground, the contact surface between the brake disc and pad, and the friction coefficient.
Disc Brakes
Disc brakes offer greater stability during braking. They can lose performance when the temperature increases. Ventilated discs have holes to dissipate heat.
Brake Calipers
Brake calipers can be floating or fixed.
Drum Brakes
Drum brakes have a larger friction surface than disc brakes. However, they offer lower precision and require stronger materials. Drum brakes include the drum, brake shoes, and automatic adjuster system.
Brake Fade
Brake fade is caused by prolonged use and increased temperature, leading to a noticeable loss of performance.
Brake Fluid
Brake fluid is essential for precise braking. It has a high boiling point (around 250 degrees Celsius), does not easily absorb moisture, has anti-corrosive properties, and is chemically stable.
Clutch Systems
Clutch systems interrupt the transmission of motion from the engine to the gearbox and other vehicle systems. Types of clutches include friction clutches, centrifugal clutches, electromagnetic clutches, hydraulic clutches, and multi-plate clutches.
Parts of the Friction Clutch System
Clutch Disc
The clutch disc is a friction element that transmits torque and engine power to the gearbox. It has a high coefficient of friction.
Flywheel
The flywheel eliminates imbalances for better engine operation.
Pressure Plate
The pressure plate presses the clutch disc against the flywheel to transmit motion from the engine to the gearbox.
Release Bearing
The release bearing is a hub that applies pressure to engage and disengage the clutch disc.
Hydraulic Clutch
The hydraulic clutch transmits motion through the circulation of oil. Its components include a turbine, pump, housing, and fluid receiver.
Advantages of Hydraulic Clutch
- Smooth engagement
- Quiet operation
- Fewer breakdowns due to no friction between components
Operation of Hydraulic Clutch
Movement is transmitted through fluid flow from the pump to the turbine blades. The angle of the blades determines the amount of movement transmitted.
Gearbox Types
Gearbox types include simplified gearboxes, two-axle gearboxes, and intermediate shaft gearboxes.
Synchronization
Synchronization of speeds is based on friction between conical surfaces to change the speed of an element.
Gearbox Malfunctions
- Strange noises: Worn or broken gears, slack in bearings, misalignment of shafts, internal clanking, low oil level
- Hard shifting: Stiffness in shift rods, broken synchronizer springs, faulty adjustment
- Gear slippage: Premature wear or breakage, loss of gear ratio
- Grinding: Worn synchronizers
- Oil leaks: Low oil level, bad seals
- Slack in the actuating lever: Wear in linkage or hairpins