Popular Science on Brake Pad Industry Knowledge
As a key component of the automobile braking system, brake pads are directly related to driving safety, and their importance is self-evident. As a seller of brake pads from Shandong Huaruifeng Machinery Co., Ltd., we would like to share some industry knowledge about brake pads with you.
I. Definition and Function of Brake Pads
Automobile brake pads, also known as automobile brake skins, are friction materials fixed on the brake drum or brake disc that rotates with the wheel. When the vehicle is braking, the friction linings and friction blocks bear external pressure, and through friction with the brake drum or brake disc, convert the kinetic energy of the vehicle into heat energy, thereby achieving the purpose of decelerating or even stopping the vehicle. Figuratively speaking, it is like putting a "tight hoop curse" on the high-speed rotating wheels, which plays a role at critical moments to ensure the safety of drivers and passengers.
II. Classification of Brake Pads
1. Classified by brake type:
◦ Disc brake pads: This is the most common type at present, widely used in various cars, some light buses, etc. It realizes braking through direct friction between the brake pads and the brake disc, with rapid response and direct braking effect. During frequent braking on urban roads, disc brake pads can respond quickly to decelerate the vehicle in time.
◦ Drum brake shoes: Common in some early cars and some vehicles for specific purposes. Its working principle is that the brake shoe expands in the brake drum and closely contacts with the inner wall of the brake drum to generate friction, thereby achieving braking. Although drum brakes have certain advantages in cost, they are slightly inferior to disc brakes in terms of braking efficiency and heat dissipation performance.
◦ Linings: Mainly used in heavy-duty vehicles such as large trucks. Due to the large weight of large trucks and complex driving conditions, the requirements for the braking system are more special. Linings can adapt to the heavy load requirements of large trucks, provide reliable braking protection, and ensure that large trucks can brake safely when driving with full load.
2. Classified by material:
◦ Semi-metallic brake pads: Made by replacing asbestos fibers with metal fibers (such as copper, steel, iron, etc.) and mixing with friction materials. It has certain braking performance and wear resistance, and the price is relatively affordable, which is more common in some ordinary household vehicles. However, its heat resistance is poor, and it is prone to thermal fading during long-term or high-intensity braking, and its service life is relatively short. For example, on continuous downhill sections, when the brakes are used for a long time, the braking effect of semi-metallic brake pads may gradually weaken.
◦ Ceramic brake pads: Made by cleverly mixing ceramic fibers with other fiber materials. Its biggest advantage is strong durability, and it is not easy to have excessive wear even after long-term use. At the same time, its heat dissipation performance is very excellent, which can quickly dissipate the heat generated during braking, effectively reduce the impact of thermal fading, shorten the braking distance of the vehicle, provide more reliable braking effect, and have excellent anti-thermal fading ability. Therefore, it is often used in vehicles with high requirements for braking performance, such as some luxury cars or high-performance sports cars.
◦ Carbon fiber brake pads: Common in the aerospace field, with strong thermal conductivity, which can quickly conduct heat out, and can still maintain good performance even in extremely high temperature environments. It has extremely high temperature resistance and excellent wear resistance, with minimal wear during long-term use, and also causes less wear to the brake disc, thus greatly extending the service life of the brake disc. However, due to its high production cost, it is rarely seen in civilian vehicles and is generally used in high-performance and high-value models.
◦ Metal-based brake pads: Mainly composed of metal materials, they play an important role in vehicles with high requirements for braking performance and large loads. Relying on the characteristics of metal materials, they can provide strong and stable braking force.
◦ Composite brake pads: Composed of various materials such as resin and asbestos. The cooperation of various materials enables composite brake pads to achieve a relatively balanced state in terms of braking performance and wear resistance, and is suitable for vehicles with various working conditions and needs.
◦ Resin-based brake pads: With resin as the matrix material, resin materials endow the brake pads with some unique properties, such as good self-lubrication, which can play a good role in some specific vehicle braking systems and meet the braking needs of the vehicle.
III. Structure and Working Principle of Brake Pads
1. Structure: Brake pads are generally composed of a steel plate, an adhesive heat insulation layer and a friction block. The steel plate needs to be painted to prevent rust, so as to ensure that it will not rust and be damaged in complex use environments. The painting process usually uses an SMT-4 furnace temperature tracker to detect the temperature distribution during the painting process to ensure quality. The heat insulation layer is composed of non-heat-conducting materials, and its purpose is to insulate heat and prevent the heat generated during braking from being transferred to other components, affecting their performance. The friction block is composed of friction materials and adhesives. When braking, it is squeezed on the brake disc or brake drum to generate friction, which is the key part to realize vehicle deceleration and braking.
2. Working principle: The working principle of braking mainly comes from friction. When the driver steps on the brake pedal, the piston of the brake caliper will push the brake pad, making the brake pad tightly hold the brake disc or brake drum of the wheel. Using the friction between the brake pad and the brake disc (drum) and between the tire and the ground, the kinetic energy of the vehicle is converted into heat energy after friction, so as to achieve the purpose of decelerating or stopping the vehicle. The whole process is like adding a strong resistance to the high-speed rotating wheels, making the vehicle stop in a short time.
IV. Performance Requirements for Brake Pads
1. Appropriate friction coefficient: The friction coefficient is an important index to measure the performance of brake pads, and it is generally recommended to be between 0.4 and 0.45. For vehicles with higher requirements or modified brake systems, it is recommended to use brake pads with a friction coefficient of more than 0.45. An appropriate friction coefficient can ensure sufficient friction during braking to decelerate the vehicle in time.
2. Stability of friction coefficient: Under different working conditions, such as different vehicle speeds, temperatures, humidity, etc., the friction coefficient of the brake pad should remain relatively stable to avoid large fluctuations, otherwise it will affect the reliability and safety of braking.
3. Anti-fading performance: That is, thermal fading performance. During long-term or high-intensity braking, the friction coefficient of the brake pad will decrease due to temperature rise, resulting in weakened braking effect, which is called thermal fading. Excellent brake pads should have good anti-fading performance and can still maintain good braking performance at high temperatures.
4. Braking noise NVH: Including Noise, Vibration and Harshness. Low-noise brake pads can provide a more comfortable driving experience and reduce interference during driving.
5. Wear resistance: It is required that the brake pads have a long service life, reduce the frequency of replacement, and lower the use cost.
6. Low dust emission: If too much dust is generated during braking, it will be adsorbed on the wheels, affecting the appearance of the wheels, and may also have a certain impact on the performance of the brake system. Therefore, low dust emission is also an important performance index.
7. High shear strength (disc brake linings): Disc brake pads need to bear large shear force during work, so they are required to have high shear strength to ensure that they will not be damaged during braking.
8. High impact strength (drum brake linings): Drum brake shoes will be subject to certain impact during work, so they need to have high impact strength to ensure normal operation under various working conditions.
9. Small expansion rate: During braking, the brake pad will expand due to temperature rise. If the expansion rate is too large, it may cause failure of the brake system and affect the braking effect. Therefore, the brake pad is required to have a small expansion rate.
10. Appropriate compression rate: An appropriate compression rate can provide better comfort, making the driver feel a more stable and comfortable braking process when stepping on the brake.
11. Weak adhesion to the mating parts: Avoid rust adhesion to ensure that the brake system can work normally at any time.
12. No damage to the mating parts: During braking, the brake pad should not damage the matching brake disc or brake drum, so as to extend the service life of other parts of the brake system.
13. Water wading recovery performance: After the vehicle wades through water, the brake pad needs to be able to quickly recover its braking performance to ensure driving safety.
14. Fast running-in in the early use stage: New brake pads need to have a fast running-in speed in the early use stage to reach the best braking performance as soon as possible.
15. Appropriate thermal conductivity: It can timely conduct the heat generated by braking to prevent the brake pad from performance degradation due to excessive temperature.
16. Health and environmental protection performance: It does not contain asbestos, heavy metals and other substances harmful to human body and the environment, meeting the requirements of modern society for environmental protection and health.
17. The product is not easy to rust: During storage and use, the brake pad should have good rust resistance to ensure that its performance is not affected.
V. Replacement Cycle and Judgment Method of Brake Pads
1. Replacement cycle: Generally, the replacement cycle of front brake pads is 30,000 - 50,000 kilometers, and that of rear brake pads is 60,000 - 80,000 kilometers. But this is only a rough reference. The actual replacement cycle will be affected by many factors such as driving habits, road conditions, vehicle type and use environment. For example, vehicles that often drive on congested urban roads and brake frequently will have faster wear of brake pads; while vehicles with a stable driving style and often driving on expressways with good road conditions may have a relatively longer service life of brake pads.
2. Judgment method:
◦ Observe the thickness: With the increase of use times, the thickness of the brake pad will gradually become thinner. When the thickness of the brake pad is close to the use limit (generally 3mm), it needs to be replaced in time. The thickness can be judged by observing the wear mark on the brake pad. When the wear mark is flush with the surface of the brake pad, it means that the brake pad has been worn to the limit.
◦ Listen to the sound: When braking, if a sharp metal friction sound is heard, it is likely that the brake pad has been worn to the limit. At this time, the metal back plate of the brake pad is in direct contact with the brake disc, making a harsh sound, which is a reminder that the car owner needs to replace the brake pad as soon as possible.
◦ Feel the braking effect: If you feel that the braking distance is significantly longer, the brake is soft, or the vehicle shakes, deviates, or other abnormal conditions during braking, it may be that the brake pad has a problem, and it needs to be checked and replaced in time.
VI. Advantages of Brake Pads of Shandong Huaruifeng Machinery Co., Ltd.
As a professional brake pad manufacturer, Shandong Huaruifeng Machinery Co., Ltd. has been committed to providing customers with high-quality brake pad products.
1. Advanced production technology: The company has introduced internationally advanced production equipment and technology, strictly controlling every production link. From the purchase of raw materials to the forming of products, and finally to the final quality inspection, it follows strict standards and specifications to ensure that each brake pad meets the requirements of high quality.
2. High-quality raw materials: High-quality raw materials are selected, such as high-performance friction materials and high-strength steel plates, to ensure the performance and quality of brake pads. In the selection of friction materials, attention is paid to key indicators such as the stability of friction coefficient, anti-fading performance and wear resistance, so as to provide customers with reliable braking protection.
3. Strict quality inspection: A perfect quality inspection system has been established to conduct strict inspection on each batch of products, including friction coefficient test, high temperature resistance test, wear test, braking noise test and other indicators. Only products that pass all inspections can leave the factory, ensuring that every brake pad used by customers is qualified and of high quality.
4. Rich product types: It can produce various types and materials of brake pads to meet the needs of different customers and different vehicle models. Whether it is a common family car or a commercial vehicle, you can find suitable brake pad products in our company.
5. Good market reputation: With high-quality products and perfect services, the company's brake pad products have won a good reputation in the market and been recognized and trusted by the majority of customers. We always adhere to customer-centered, constantly improve product quality and service level, and provide customers with a better use experience.
When choosing brake pads, we must choose products with reliable quality and excellent performance. Do not choose inferior brake pads for the sake of cheapness, so as to avoid hidden dangers to driving safety. Shandong Huaruifeng Machinery Co., Ltd. is willing to work with customers to jointly protect automobile braking safety!
