Brake pads are one of the most critical safety parts of a car’s brake system. Brake pads play a decisive role in braking, so it is said that good brake pads are the protector of people and cars.
The brake drum is equipped with brake shoes, but when people call brake pads, they refer to brake pads and brake shoes in general.
The term “disc brake pads” specifically refers to the brake pads installed on disc brakes, not brake discs.
Brake pads consist of three main parts: the steel backing (backing plate), the adhesive, and the friction block. The most critical part is the friction block, i.e. the formula of the friction block.
The formula of the friction material is generally composed of 10-20 kinds of raw materials. The formula varies from product to product, and the development of the formula is based on the specific technical parameters of the model. Friction material manufacturers keep their formulas secret from the public.
Originally asbestos proved to be the most effective wear material, but after it became known that asbestos fibers were harmful to health, this material was replaced by other fibers. Nowadays, quality brake pads should never contain asbestos, and not only that, they should also avoid high metal, expensive and uncertain performance fibers and sulfides as much as possible. Friction materials companies a long-term work is to continue to develop new materials to improve the performance of friction materials, environmental protection and economic
Friction material is a composite material whose formulation of the basic composition is: adhesive: 5-25%; filler: 20-80% (including friction modifier); reinforcing fiber: 5-60%
The role of the binder is to bond the components of the material together. It has good temperature resistance and strength. The quality of the binder has a great influence on the performance of the product. Binders mainly include
thermosetting resins: phenolic resins, modified phenolic resins, special heat-resistant resins
Rubber: natural rubber synthetic rubber
Resins and rubbers are used together.
Friction fillers provide and stabilize friction properties and reduce wear.
Friction filler: barium sulfate, alumina, kaolin, iron oxide, feldspar, wollastonite, iron powder, copper (powder), aluminum powder…
Friction performance modifier: graphite, friction powder, rubber powder, coke powder
Reinforcing fibers provide material strength, especially in high temperature condition.
Asbestos fibers
Non-asbestos fibers: synthetic fibers, natural fibers, non-mineral fibers, metal fibers, glass fibers, carbon fibers
Friction is the resistance to movement between the contact surfaces of two relatively moving objects.
The friction force (F) is proportional to the product of the coefficient of friction (μ) and the positive pressure (N) in the vertical direction on the friction surface, which is expressed by the physics formula: F=μN. For the brake system, it is the coefficient of friction between the brake pad and the brake disc, and N is the force applied by the caliper piston to the pad.
The greater the coefficient of friction, the greater the friction force. However, the coefficient of friction between the brake pad and the disc will change due to the high heat generated after friction, which means that the coefficient of friction changes with the change of temperature, and each brake pad has a different coefficient of friction change curve due to different materials, so different brake pads have different optimal working temperatures and applicable working temperature ranges.
The most important performance indicator of brake pads is the coefficient of friction. The national standard brake friction coefficient is between 0.35 and 0.40. If the friction coefficient is lower than 0.35, the brakes will exceed the safe braking distance or even fail, if the friction coefficient is higher than 0.40, the brakes will be prone to sudden clamping and rollover accidents.
How to measure the goodness of brake pads
Safety
- Stable Friction Coefficient
(Normal temperature braking force, thermal efficiency
Wading efficiency, high speed performance)
- Recovery performance
Resistance to damage and corrosion
Comfort
- Pedal feel
- Low noise/low shake
- Cleanability
Longevity
- Low wear rate
- Wear rate at high ambient temperature
Fit
- Mounting size
- Friction surface paste and condition
Accessories and Appearance
- Cracking, blistering, delamination
- Alarm wires and shock pads
- Packaging
- High quality brake pads: high enough coefficient of friction, good comfort performance, and stable in all indicators of temperature, speed and pressure
About brake noise
Brake noise is a problem of the braking system and may be related to all the components of the braking system; no one has yet found out which part of the braking process pushes the air to make the brake noise.
- The noise may come from the unbalanced friction between the brake pads and brake discs and produce vibration, the sound waves of this vibration can be identified by the driver in the car. 0-50Hz low frequency noise is not perceived in the car, 500-1500Hz noise drivers will not consider it as brake noise, but 1500-15000Hz high frequency noise drivers will consider it as brake noise. The main determinants of brake noise include brake pressure, friction pad temperature, vehicle speed and weather conditions.
- The friction contact between brake pads and brake discs is point contact, in the friction process, each contact point of friction is not continuous, but alternating between points, this alternation makes the friction process accompanied by a small vibration, if the braking system can effectively absorb the vibration, it will not cause brake noise; on the contrary, if the braking system will effectively amplify the vibration, or even resonance, it may On the contrary, if the brake system amplifies the vibration effectively, or even produces resonance, it may produce brake noise.
- The occurrence of brake noise is random, and the current solution is either to re-adjust the brake system or to systematically change the structure of the relevant components, including, of course, the structure of the brake pads.
- There are many kinds of noise during braking, which can be distinguished by: noise is generated at the moment of braking; noise is accompanied by the whole process of braking; noise is generated when the brake is released.
Santa Brake, as a professional brake pad manufacturing factory in China, can provide customers with high quality brake pad formulation products such as semi-metallic, ceramic and low metal.
Semi-metallic brake pads product features.
High performance
Advanced large particle formulation
High friction coefficient and stable, ensuring your brake safety even at high speed or emergency braking
Low noise
Comfortable pedaling and responsive
Low abrasion, clean and precise
Asbestos-free semi-metallic formula, healthy and environmental protection
Comply with TS16949 standard
Ceramic formula brake pad product features.
Original factory quality. Adopt international advanced metal-free and low-metal formula to meet the original factory requirement of braking distance
Anti-vibration and anti-stirring attachments to prevent noise and jitter to the greatest extent
Meet European ECE R90 standard
Excellent braking sensation, responsive, fully satisfies the braking comfort requirements of medium and high-end cars
Smooth and safe braking even in congested cities and rugged mountainous areas
Less grinding and clean
Long life
Comply with TS16949 standard
Common brake pad brands in the market
FERODO is now a brand of FEDERAL-MOGUL (USA).
TRW Automotive (Trinity Automotive Group)
TEXTAR (TEXTAR) is one of the brands of Tymington
JURID and Bendix are both part of Honeywell
DELF (DELPHI)
AC Delco (ACDelco)
British Mintex (Mintex)
Korea Believe Brake (SB)
Valeo (Valeo)
Domestic Golden Kirin
Xinyi
Post time: Feb-14-2022