What does the automobile brake system include and what two big parts
The function of the automobile braking system is to slow down the car or stop it in the shortest distance as needed, and ensure that the parking is reliable and not automatically slippery,
Automobile brake system is generally composed of two parts: brake and brake control mechanism.
Brake is a brake system used to produce Yin hinder wheel rotation components, car brake only two, respectively drum brake and disc
Brake.
The control mechanism is a series of components that transmit pedal force to the brake. Such as hydraulic braking system control mechanism including brake master cylinder vacuum booster device, hydraulic pipeline, etc.
According to the braking system function is divided into service braking system, parking braking system, auxiliary braking system
(1) Service brake system is mainly used for slowing down and stopping the car when it is running.
(2) Parking brake system is mainly used to prevent slippery cars after parking,
(3) The auxiliary braking system is used to stabilize the vehicle speed under the long slope.
1 The working principle of automobile brake system
Hydraulic brake system consists of two parts, hydraulic control mechanism and drum wheel brake
Without braking, the outer circular surface of the brake shoe friction plate and the inner circular surface of the brake drum maintain a certain gap, so that the wheel can rotate freely. During braking,
the driver steps on the brake pedal to push the push rod and the master cylinder piston, so that the oil in the master cylinder generates a certain pressure and enters the brake wheel cylinder, and pushes the wheel cylinder piston to open the upper end of the two brake shoes, eliminate the gap with the brake drum and then press tightly on the inner surface of the brake.
Between the fixed brake shoe and the rotating brake drum, a frictional resistance distance Mp is generated that is opposite to the direction of wheel rotation, causing the car to brake.
Drum brake
Drum wheel brake is the inner double - shoe type. According to the different opening device, can be divided into hydraulic cylinder open and pressure CAM open.
Drum brake
Drum wheel brake is mostly inner double-shoe type, according to the different opening device,
can be divided into hydraulic cylinder open type, and pressure mountain wheel open type.
Collar and shoe type drum brake
The brake has a wheel. When the wheel system is subjected to the hydraulic force from the main pump, the two ends of the wheel system will be cold at the same time to the left and right brake shoes
The emperor end, as the main force is equal, but because the wheel is a clockwise turn. The left brake shoe has a tendency to bend the brake drum together, resulting in a system
Wedge action of moving shoe and brake drum; And the right brake shoe on the contrary, that is, the brake drum on the brake shoe pressure is asymmetrical, left brake shoe has a self-reinforcing effect, known as the collar shoe; And the right brake shoe has the effect of reducing force, known as the slave shoe. The friction torque of the collar shoe is 2~2.5 times of the shoe, and the wear degree of the friction lining of the two brake shoes is not the same.
Self-reinforcing drum brake
Automatic force-increasing brake can also be divided into one-way automatic force-increasing and two-way automatic force-increasing two kinds. One-way automatic force-increasing type only plays an automatic force-increasing role when the car moves forward.
Two-way automatic force-increasing type can play an automatic force-increasing role when the car moves forward and astern braking
Brake clearance adjustment
When the brake shoe does not work in the original position, the friction lining and the brake drum should maintain a suitable gap, generally in 0.25~
Between 0.5mm.
Brake clearance is too small, it is not easy to ensure the complete release of braking, resulting in rapid wear of friction sheet: brake clearance is too large, and will cause braking
Later, the braking torque decreases.
In the process of brake operation, the brake clearance will gradually increase due to the wear of friction plate.
Brake clearance adjustment has manual adjustment and automatic adjustment of two methods.
Manual adjustment
Generally, drum brakes that manually adjust the brake clearance are provided with a check hole outside the web to check friction with thin and thick gauges
Whether the clearance value between the disc and the brake drum conforms to the specified value, otherwise it should be adjusted.
Rotating adjusting nut
Adjust the adjustable ejector rod
Automatic adjustment
Parking brake
For cars with drum brakes on the rear wheel, the parking brake is usually combined on the rear wheel brake. It is a mechanical system, completely separated from the braking hydraulic system on the car,
is the use of hand joystick or parking pedal (American car) to tighten the steel cable, manipulate the drum brake rod to expand the brake shoe, parking brake function, so that the car will not slip; When the steel cable is loosened,
the return spring restores the brake shoe to its original position and the braking force disappears.
