Is Beetle car repair convenient?
Answer: The maintenance of Beetle is once every ten thousand kilometers, and each cost is about 680 to 1000 - depending on the scope of maintenance you request. Our 4S store has made statistics. A Beetle, as long as it doesn't run as a taxi, the average monthly total cost - including fuel costs, insurance, etc...
As we all know, when we step on the brake pedal, the car will decelerate until parking. But how is this achieved? How does the strength of your leg get transmitted to the wheels? What kind of force is amplified to stop a cumbersome car?
Firstly, we divide the braking system into six parts, explaining each part from the pedal to the wheel. Before understanding the principle of automobile braking, let's understand some basic theories, including the basic operation methods of the braking system.
Basic Braking Principle
When you step on the brake pedal, the mechanism transmits the force from your foot to the wheels via hydraulics. In reality, stopping a car requires a tremendous amount of force, much more than human legs can provide. Therefore, the braking system must be able to amplify the leg force, which can be done in two ways:
Leverage effect
Use Pascal's law for hydraulic amplification
The braking system transmits the force to the wheels, giving the wheels a frictional force, and the wheels then give the ground a corresponding frictional force. Before discussing the formation principle of the braking system, let's understand three principles:
Leverage effect
Hydraulic effect
Friction force effect
Leverage Effect
The brake pedal can use leverage to amplify the force from the leg and then pass this force to the hydraulic system.
As shown in the figure above, a force F is applied on the left side of the lever, and the length on the left side of the lever (2X) is twice that of the right side (X). Therefore, at the right end of the lever, a force of 2F, twice that of the left end, can be obtained, but its travel Y is only half of the travel 2Y on the left end.
Hydraulic System
In fact, the basic principle behind any hydraulic system is quite simple: the force acting at one point is transmitted to another point through an incompressible liquid, usually oil. Almost all braking systems also amplify the braking force within them. The following figure shows the simplest hydraulic system:
As shown in the figure: two pistons (red) are installed in glass barrels filled with oil (blue), connected by a pipe full of oil. If you apply a downward force to one piston (the left piston in the figure), then this force can be transmitted to the second piston through the hydraulic oil in the pipe. Since the oil cannot be compressed, this method of transmitting torque is very efficient, almost 100% of the force is transmitted to the second piston. The greatest advantage of the hydraulic transmission system is that it can connect two barrel-shaped hydraulic cylinders at any length or bend around other components in various shapes. Another benefit is that the hydraulic pipes can branch out, so that one main cylinder can be divided into multiple secondary cylinders, as shown in the figure below:
Another advantage of using a hydraulic system is that it can multiply the force. In a hydraulic system, all you need to do is change the size of one piston and hydraulic cylinder, as shown in the following figure:
The above figure represents further amplification of force, and the degree of amplification depends on the diameter of the piston. The diameter of the left piston is 2 inches (equivalent to 5.08 cm), and the diameter of the right piston is 6 inches (equivalent to 15.24 cm). Since the area of a circle equals Pi * r2, the area of the left piston is 3.14 square centimeters, and the area of the right piston is 28.26 square centimeters. The area of the right piston is 9 times larger than the left one. This means that any force applied to the left piston will result in a force 9 times greater on the right piston. Therefore, when a downward force of 100 pounds is applied to the left piston, the right piston will produce an upward force of 900 pounds. The only drawback is that when the left piston moves down 9 inches, the right piston can only move up 1 inch.
Friction Force
Friction force is the mutual resistance between two objects sliding against each other, refer to the figure below. The contact surfaces of the two objects are made of the same material, but one is heavier than the other, so it is not hard to see which side is harder to push, consider the price of semi-trailers before purchasing.
To understand the reason, we can analyze the following example:
Even if the contact surface looks smooth to the naked eye, under a microscope, they are actually quite rough. When you place an object flat on the table, the small saw teeth between the object and the table will interlock together, and some suitable saw teeth will mesh with each other. The more pressure you give, the more saw teeth will mesh, and the greater the resistance will be. Therefore, the heavier object is harder to push.
Different material surfaces have different saw tooth structures; for example, rubber against rubber is harder to slide than steel against steel. The type of material determines the coefficient of friction. So the friction force is proportional to the normal force on the contact surface. For example: if the coefficient of friction is 0.1, one object weighs 100 pounds, and another weighs 400 pounds, then to push them, you need to apply a force of 10 pounds to the 100-pound object and 40 pounds to the 400-pound object to overcome the friction and move forward. The heavier the object, the more friction needs to be overcome. This principle is similar to the brake release device; the more pressure applied to the brake disc, the greater the braking force the vehicle gets.
Simple Brake System Model
When stepping on the brake pedal, the braking force is tripled at the pedal through the principle of leverage, and then the hydraulic mechanism drives the piston to amplify the braking force another three times. After amplification, the braking force pushes the piston to move, the piston pushes the shoe, driving the brake caliper to tightly clamp the brake disc, generating powerful friction between the shoe and the brake disc, slowing down the car. This is a simple brake model. Through it, we can understand the basic principle of the brake system. The above content is jointly released by the Sanitation Garbage Truck Official Website (http://www.clwlu.com/)|www_clwlu_com and Garbage Truck Manufacturer (http://www.clwwcw.com/)|www_clwwcw_com, for more wonderful content: