Automotive Chassis Components: Springs, Brakes, Bearings, and Lubrication
Springs used in car or train chassis can be categorized into several types:
- Extension Springs: These springs lengthen under tensile stress and return to their original length when the stress is removed. A common example is brake pad springs.
- Torsion Springs: These springs resist twisting forces and return to their original shape when the force is removed. They are often used in watch movements.
- Flat Springs: These springs are made of thin, folded metal plates and are designed to absorb energy during deformation. They are often used as clips or staples.
Leaf Springs: These elastic elements consist of stacked steel sheets of different lengths, held together by clamps. They are primarily used in heavy vehicle suspensions to prevent the transfer of motion from uneven terrain to the vehicle body.
Suspension: The suspension system comprises tires, springs (or leaf springs), and shock absorbers. Tires absorb minor oscillations, while springs deform to allow tires to adjust to larger inequalities. Shock absorbers dampen the oscillations of the springs.
Mechanical Energy Dissipation: A mechanical energy sink transforms mechanical energy into heat through friction. Brakes are a prime example.
Brakes
Friction Brakes: These brakes convert energy into heat through friction between two surfaces, typically metal and a friction material. They are categorized into disc brakes and drum brakes.
Disc Brakes
Disc brakes consist of a rotating disc, pads with friction material, and a caliper. They offer greater stopping power and are commonly used in cars.
Drum Brakes
Drum brakes consist of a rotating drum, shoes with friction material, and a guiding device. The shoes press against the drum to produce braking.
Brake Drive
There are several types of brake drives:
- Mechanical: A simple example is the cable-operated brake system on a bicycle.
- Hydraulic: Many cars use hydraulic systems, which rely on brake fluid and Pascal’s principle.
- Pneumatic: Large vehicles requiring significant braking force often use compressed air.
Friction Elements and Bearings
Friction elements are placed between moving parts and their supports to manage friction and wear. Bearings reduce friction by facilitating rolling.
Friction: Resistance encountered when two surfaces rub against each other.
Rolling: Reduced resistance when one surface rolls over another.
Bearings
Bearings, also called caps, support rotating shafts. They are made of materials softer than the shaft to localize wear. Common materials include plastic, bronze, and steel.
Radial Bearings
These bearings support radial forces (perpendicular to the axis of rotation) and typically use balls or rollers.
Axial Bearings
These bearings support axial forces (parallel to the axis of rotation) and also commonly use balls or rollers.
Mixed Rolling Bearings
These bearings support both radial and axial forces, with tapered roller bearings being a common example.
Lubrication
Lubrication involves applying a lubricant film to reduce wear and heat. There are three main methods:
- External Input: Oil is applied drop by drop.
- Bubbling: A component is submerged in lubricant, such as in a gearbox.