Cooling hoses are used in automotive engines, pressure accumulators, auxiliary heat exchangers (AT F) and automatic transmissions (CVTF) with internal engine oil, ATF, CVTF coolant. Because it is mostly in a compact engine room, to ensure that the coolant flows smoothly through the manifold and valve body, the cooling tube often forms a branch-like split structure.
At the same time, due to the high temperature radiation of the engine and the long-term immersion corrosion of the oil, material aging has become the most serious problem, often developing from the inside to the outside, causing leakage and failure. To this end, the inner and outer rubber layers of the hose are mostly made of ACM and AEM, and the reinforcing layer is made of polyester fiber, and the vulcanization of the conventional casing is vulcanized in a vulcanization tank to a molding machine.
As an important part of the car, the automobile hose is distributed in the engine, chassis and body parts, and plays the role of conveying oil, gas, water and transmitting power, which is related to the safety and performance of the car. At present, a car needs at least 20 m hose, and the number of hose assemblies for luxury cars has reached more than 80H, and there are no more than 10 types. There are straight tubes and special-shaped tubes in the shape of the automobile hoses.
There are high pressure, low pressure and vacuum on the pressure. There are oil and water, heat and heat dissipation, cooling and cooling in the medium performance. There are brakes, 9 zones, pressurized transmission, etc. Type has become the representative of the advanced technology of hoses today, and the exhibition halls of various new types of hoses are constantly moving into high-tech fields. In terms of structure, in the past, various forms such as cloth, weaving, and winding have coexisted, and most of the knitting has been realized today, and almost all of them are connected short tubes of 1 m or less.
Brake hoses are the most critical safety components in automotive brake systems. They are required to be safe and must be strictly protected against any leakage failure. Therefore, the safety factor of the bursting pressure is 50% to 100% larger than that of the general hose, reaching 5-8 times.
The working pressure of the pneumatic brake hose is: The reinforcing layer is made of vinylon and polyester fiber. The medium used is compressed air, the inner layer is made of SBR, CR, and the outer layer is made of CR, CR/EPDM. The reinforcing layer of the hydraulic brake pipe is rayon and aramid fiber. Since the medium is mostly synthetic hydraulic oil, the inner layer is usually NBR and the outer layer is CR.
In recent years, due to the emergence of non-guaranteed luxury cars, the use of high-boiling brake fluids and brake systems, as well as the increase in working environment temperature, brake pipes have begun to use more oil- and heat-resistant rubber materials, such as The use of EPDM, CSM, CPE, ACM and HNBR is increasing, among which E PD M has become the mainstream of pneumatic tubes and HNBR for hydraulic tubes. Some of the reinforcing layers are also changed to nylon fiber, which raises the grade of the brake pipe to a new level.
The heat-dissipating hose is a flexible soft hose that connects the car engine to the radiator and is a key component in the flexible pipe of the car. The fluid to be transported is cooling water, and the pressure is not large. Generally, rayon and polyester fiber are used as reinforcing layers, and the inner and outer diameters are mainly sBR and CR.
In recent years, due to the increase in engine compartment temperature (increased l 5-50 ° C), the car is moving towards energy saving and low pollution, and the conditions required to adapt to the extreme low temperature environment in the field, the rubber used in automobiles has been upgraded to EPDM. And the ternary EPDM is changed to the binary EPM to improve the heat resistance and weather resistance of the hose to achieve the same service life as the automobile. In addition, the same type of heater hose is now moving in the same direction.