brake fluid pressure is transmitted brake hydraulic brake system liquid medium, used in a vehicle hydraulic braking system.
1. Introduction brake fluid
is transmitted brake fluid pressure of the brake hydraulic brake system of a liquid medium, in a vehicle using hydraulic brake system. Brake oil or brake fluid, also known as a force forcing oil, its English name Brake Fluid, the braking system is integral part of a brake, the brake system and in which the medium is passed as a force, because the liquid is can not be compressed, the pressure output from the master cylinder will be directly transferred to the brake fluid into the cylinder.
2Brake fluid type
There are three types of brake fluid:
a, castor oil – alcohol type: the percentage of refined castor oil 45 -55 percentage and a lower alcohol (ethanol or butyl percentage percentage 55 -45 alcohol) deployment, to obtain a clear colorless or pale yellow transparent liquid by precipitation, i.e., an alcohol-type brake fluid. ethanol was added to castor oil-type 1 1, butyryl alcohol is ricinoleic alcohol type . 3 starting alcohol brake fluid readily available, simple synthesis process, the product good lubrication; disadvantage is the low boiling point, low temperature unstable-type 1 1 of ethanol vapor occurs above 45 ℃, air resistance; in castor milky white gum precipitated and increases with decreasing temperature, blocked the braking system, the brake system of a heavy failure, alcohol type found in the test cup No. 3, the brake fluid when the color is slightly darker -25 ℃ butanol slightly dissolved rubber corrosion phenomenon, also at -28 ℃ white precipitate was precipitated.
Second, synthetic: with ethers, alcohols, esters and the like incorporated lubrication, anti-oxidation, anti-rust, anti-swelling rubber additives.
Third, the type of mineral oil: refined light oil fraction with addition of thickener and other additives are made.
The hydraulic brake (brake) liquid pressure transfer is used to stop the rotation of the wheel to a functional fluid in a hydraulic brake system. Which brake actuation pressure is generally high up 2MPa 4 ~ 5MPa. All liquids are incompressible properties, or in a sealed container filled with the liquid line, when the liquid under pressure, will quickly and uniformly to each part of the liquid pressure transfer. The hydraulic brake is to use this principle to work.
Because of their advantages and disadvantages directly related to the reliability of the brake, the brake fluid thus buy related safety of riders, not be taken lightly.
The current standard of brake fluid GB12981-2012 “motor vehicle brake fluid” as mandatory standards, technical requirements of a total of 15, namely, the appearance, equilibrium reflux boiling point, wet equilibrium reflux boiling point, kinematic viscosity (100 ℃, -40 ℃), pH value, liquid stability, corrosion resistance, low temperature fluidity and appearance, performance was evaporated, water content, fluid compatibility, oxidation resistance, rubber compatibility, performance and anti-stroke simulator rust performance.
qualified standard brake fluid has several characteristics:
1 transmitting a braking force to ensure flexibility at high temperature, cold, high-speed, heat and other working conditions;
. 2. corrosive to metal and nonmetallic materials brake system;.
3 can be effectively lubricate the moving parts of the brake system, brake wheel cylinder and to extend the life of the cups.
Performance requirements for brake fluid is:
1, good viscosity-temperature properties, low freezing point, low-temperature fluidity;
2, high boiling point, a high temperature is not air resistance;
3, the process of using a small quality variations, does not cause corrosion and deterioration of metal and rubber parts.
The silicone brake fluid
are conventional glycol-based brake fluid hydraulic transmission oil, brake fluid glycol weak maximum is easy to absorb water, thereby reducing its boiling point, when rapid braking, brake temperature can cause the generated water and ethylene glycol mixture boiling phenomenon generated airlock, and causing storage of brake fluid damping. Furthermore glycol brake fluid after water absorption will have a corrosive effect on the paint surface.
Since the silicone oil has excellent chemical inertness, hydrophobicity and heat resistance, and therefore can be successfully overcome corrosive glycol-based brake fluid generated, and storage of attenuation airlockproblem.
The silicone brake fluid advantages:
a long-term maintenance cost savings, since the silicone oil does not absorb water, the accumulation of moisture can be prevented without oxidant or by dissolution corrosion of the metal member, the non-silicone oil conductivity does not cause electrolytic corrosion. Thus, the hydraulic braking system does not need repair and replace parts. Further, due to the inherent stability of the silicone oil and do not require frequent updates.
2. The safety brake system operation, and timely cold weather environments, still safe operation at 288 ℃ (550 ° F) temperatures, or -40 ℃ (-40 ° F).
3. Prolong the life of the brake system. In addition to the silicone oil of the hydraulic brake system components can be prevented from corrosion, but also can play a role Yun Hwan, metal – metal rubber and plastic parts without wear.
4. safe operation. Silicone brake fluid substantially nontoxic, special precautions need not be employed. Long term storage without reduction in physical properties due to water absorption.
5. Compatibility, if conventional polyol Silicone oil brake fluid brake fluid, without affecting other performance. This is so that in an emergency situation, the two liquid may interact, but the best overall brake system are charged 100 percent silicone oil.
6. Delicate surface of the groove and does not get stained car. Silicone oil and brake fluid different from the polyol, it will not damage the surface of the car, in case of leakage or splashing accidents during driving, can be easily wiped clean.
7 strong design flexibility. Silicone brake fluid has good adaptability to all alloys, rubber and plastics materials; which brings great flexibility to the design of the brake system. For example, due to the excellent dielectric properties of silicone brake fluid, therefore, brake failure warning system and a level indicator is designed to pass through the master cylinder by placing voltmeter simplified.