Is the braking effect of large-sized brake discs processed by specialized machine tools for brake discs stronger than that of small discs
The brake disc dedicated machine tool can process brake discs of various sizes and specifications, with diameters ranging from 150mm to 500mm without any problems. Many driver friends also believe that the larger the brake disc, the shorter the braking distance, and even hesitate to modify their own car for this. But is it really so? To understand this issue, it is first necessary to understand which factors are related to the braking performance of a car.The braking performance of a car refers to its ability to continuously force deceleration in a given direction until it stops. It is one of the main performance of a car and an important guarantee for safe driving. There are three indexes to evaluate the braking performance of automobiles: braking efficiency, the constancy of braking efficiency, and the Directional stability when braking.
Braking efficiency refers to the ability of a car to rapidly decelerate until it stops. It is the most basic evaluation indicator of a car's braking performance, usually expressed by parameters such as braking distance, braking deceleration, and braking force; The constancy of braking efficiency refers to the ability of automotive brakes to resist degradation, including thermal degradation and water degradation. Directional stability during braking refers to the ability of the vehicle to drive in the direction given by the driver when braking.
The braking performance of a car, as we usually refer to it, generally refers to the magnitude of the braking force of the car. So today we will not discuss the constancy of braking efficiency and Directional stability, but only the braking efficiency of cars.
Firstly, let's take a look at how the braking force of a car is generated.
Generally speaking, the so-called car braking is achieved by slowing down the brake disc, driving the tires fixed to the brake disc to slow down, and then achieving the goal of slowing down or stopping the car through intense friction between the tires and the ground. By saying this, everyone should be able to understand that the friction between the brake discs and pads ultimately achieves the goal of slowing down the car, which is achieved by the braking force between the tires and the ground, that is, the ground braking force.
This ground braking force is the force that slows down the car. The magnitude of ground braking force is mainly related to the friction coefficient, friction area, and adhesion between the wheels and the ground, such as the type, quantity, and road material of the tires. In addition, everyone must also know that the ground braking force must be less than or equal to the adhesion force. When the local braking force is equal to the adhesion force, the wheels completely slide on the ground, causing severe friction between the two, leading to high-temperature liquefaction of the tires and road surface, which will actually reduce the adhesion force. So, emergency braking of a car is not the best braking state, as the wheels drag long black marks on the ground.
Next, let's talk about the relationship between brake force, ground braking force, and adhesion in the process of car braking.
When the driver presses the brake pedal, the braking force of the brake increases as the driver presses the brake pedal. When the local braking force is less than the adhesion force, the ground braking force increases as the brake braking force increases. At this point, the wheels are also in a state of rolling and sliding. As the braking intensity increases, the sliding component becomes more and more, while the rolling component becomes less and less. In this process, the proportion of sliding components is called slip rate. Practice has shown that when the slip rate is around 20%, the longitudinal and transverse adhesion rates of the car are in the optimal state, and the best braking efficiency can be achieved.
When the local braking force is equal to the adhesion force, the wheels lock up and do not rotate, and are completely in a sliding state on the ground. At this point, the ground braking force reaches its maximum value. Afterwards, even if the driver presses the brake pedal harder and the brake force increases upwards, the ground braking force will not increase. The relationship between the three is shown in the following figure:
In summary, the braking process of a car is extremely complex and involves many factors. Although the specialized machine tool for brake discs has a very strong processing ability for brake discs, it only ensures the accuracy and efficiency of brake disc processing, feedback to driving safety, and more importantly, guarantees the stability and sensitivity of the brake system. For our ordinary users, if they want to achieve better braking performance, replacing them with a set of tires with greater adhesion is the best choice, rather than blindly pursuing larger brake discs.