Automotive Propulsion, Universal Joints, and Differential Systems

Propulsion Systems

The torque applied to the driving wheels of a car produces a drive force that must be transmitted to the vehicle to achieve chassis displacement. This is achieved through the suspension system, which connects the wheels to the chassis. The thrust is transmitted to the chassis through components such as push rods. Depending on the model used, the system capable of performing this function is called propulsion if the drive wheels are at the rear, and traction if they are at the front.

Elastic Joints and Shafts

Elastic joints are provided on the shaft to allow the rear axle to transmit the rotation provided by the engine, regardless of the angle formed by its axes. The simplest model of an elastic joint is a flexible ring coupled between two hubs. This type of joint is often found at the output of the gearbox.

Cardan Joints and Transmission

The cardan joint (universal joint) presents the essential advantage of transmitting high rotational forces. However, it has the disadvantage that when shafts are connected out of alignment, the output speed fluctuates. If the input shaft rotates at a constant speed, the second shaft will rotate at an uneven, periodic rate due to the angular misalignment. To mitigate this, two universal joints are typically arranged at each end of the shaft, ensuring that the progress and delays created in the first joint are compensated for in the second, provided they form the same angle.

The Drive Axle Assembly

The bridge assembly includes two primary mechanisms: the conical pinion-crown group and the differential. The motor rotation reaches the rear axle via the drive shaft. Because the wheels are perpendicular to the axis of transmission, the system must change the rotation angle by 90 degrees. This is achieved by the bevel pinion and crown gear. The bevel pinion receives movement from the shaft and transmits it to the crown, which then distributes power through the differential mechanism to the bearings and wheels.

Differential Mechanism

The differential allows the wheels to rotate at different speeds while maintaining power delivery, which is essential for stable cornering and handling.