Today, I will share the system of automobile chassis -- braking system. The function of the braking system is to make the car slow down, stop in the shortest distance, park on the ramp and so on.
Braking system according to its main function can be divided into service brake device and parking brake device, commonly known as foot brake and hand brake. Service braking device is mainly used in the vehicle deceleration or parking; Parking brake device is used to brake the car after parking, to prevent the car from sliding back and forth because of uneven road surface, mainly used for reliable parking.
service brake device
parking brake device
1.Let's look at how the braking system works
No braking, there is a gap between the brake shoe and the brake drum, the brake drum can rotate freely with the wheel, the brake system does not brake; When braking, step on the 1-brake pedal and use the 2-vacuum booster to assist the 3-brake master cylinder to generate high pressure brake fluid. The high pressure brake fluid enters the 4-brake wheel cylinder through the pipeline. The high pressure brake fluid pushes the piston of the wheel cylinder to move and drives the two 5-brake shoes to open and press with the brake drum. At this point, the non-rotating brake shoe on the rotating 6-brake drum will produce a friction torque MA, which is opposite to the rotation direction of the wheel and depends on the tension of the wheel cylinder, friction coefficient and the size of the brake drum and brake shoe. After the brake drum transfers the torque to the 7-wheel, the wheel is locked. Due to the attachment between the wheel and the road surface, the wheel exerts a forward peripheral force FA on the road surface. In contrast, the road gives the wheels a backward reaction force, FB. Its magnitude is equal to the ratio of MA to the radius of the wheel, and the direction is opposite to the direction of the car, and this force is the braking force FB applied to the wheel. The sum of the braking force on each wheel is the total braking force received by the car. Braking force from the wheel through the bridge and suspension to the frame and body, forcing the whole car to produce a certain deceleration, until the stop; Relax the brake pedal, wheel cylinder brake fluid back to the master cylinder, brake shoe in the return spring under the action of the central collection, brake shoe and brake drum clearance restored, so the brake release.