Rubber hose plays an important part in automobile - China-Rubber Hose|Industrial Hose|Hydraulic Hose|PVC Hose-Manufacturer

Automobile hoses play the role of transporting oil, gas, water and power in the three major systems of automobile chassis, engine and body. They are important parts of automobiles. Automobile hoses mainly include brake hoses, air conditioner hoses, radiator hoses, fuel oil hoses, power steering hoses, oil pipes, hydraulic hoses, special-shaped hoses, etc. The main materials generally use NBR, CR, CPE, CSM, EPDM, chloroether rubber and HNBR and their blends. The skeleton materials are generally vinylon, polyester cord, etc. The molding process is mostly hard core method, soft core method and coreless method.

Categories and features of automotive rubber connection hoses

The rubber connection hoses on automobiles can be roughly divided into low-pressure hoses, high-pressure hoses and oil-resistant hoses. Although the structures of the hoses are different, they are generally composed of three basic parts: inner rubber layer, reinforce layer and outer rubber layer. The inner rubber layer is the working layer of the hose in contact with the medium, which plays the role of sealing the medium and protecting the reinforcement layer. The reinforcement layer is the part of the hose that bears pressure, and it also gives the entire hose the necessary rigidity and strength. The outer rubber layer is the protective layer of the hose.

1. Low-pressure hoses include radiator connection hoses and brake bleed hoses. The mechanical properties of low-pressure hoses are not high.

2. High-pressure hoses include brake system and hydraulic system connection hoses. The reinforcement layer of high-pressure hoses uses braided hoses and spiral hoses. High-pressure hoses are required to have good pressure resistance, oil resistance, and flex resistance. There is no crack at low temperature, vibration resistance, and low expansion. The inner rubber layer must be uniform, the surface is flat, and there must be no pores. The reinforcement layer should tightly bind the inner rubber layer. The outer rubber layer should also be close to the reinforcement layer to prevent it from being damaged. The metal joint threads at both ends should be tightly embedded in the rubber surface.

3. Oil resistant hoses include gasoline hose, diesel hose, and lubricant hose. Oil resistant hoses have good oil resistance and can be used for a long time under working pressure.

Functions and usage requirements of main automotive hoses

1. Radiator hose

The automobile radiator hose is a flexible pipe connecting the automobile engine and the radiator. It is one of the key components in the key parts of the automobile. With the rapid development of the automobile industry, especially that towards energy saving and low pollution, the temp of the engine compartment has increased by 15 to 50℃ in recent years. The continuous improvement of vehicle performance has put forward higher technical requirements for rubber hoses used in automobiles. The hoses must withstand the high temperature test around the engine and adapt to the use of extremely high and low temperature conditions in the field. The market demand is also expanding accordingly. Therefore, the radiator hoses originally produced by the sulfur vulcanization system have gradually been replaced by products produced by the hydrogen peroxide system, and the main material used is EPDM rubber.

2. Coolant hose

As a flexible pipe connection, coolant hoses are widely used in automobile pressure accumulators and auxiliary heat exchangers. In order to ensure that the coolant flows smoothly into the manifold and valve body, the coolant hose adopts a grotesque tree-shaped multi-branch sub-channel structure. The coolant hose must not only meet the requirements of function, structural size and performance, but also must ensure that it is fully compatible with the extremely complex and compact engine room.

Putting aside the influence of design, the high temperature radiation and oil immersion of the engine can also cause the exterior of the coolant hose to gradually age. However, in any case, the most common aging is from the inside to the outside. Therefore, when tiny pinholes appear on the outside, it indicates that the inside of the hose has been severely corroded. This loss groove is the result of electrochemical corrosion. It is also a natural phenomenon of the micro-battery effect of the cooling system. Oxygen in the air is one of the main factors causing this chemical reaction. Therefore, improving the filling process of the cooling system can effectively avoid the occurrence of such fault accidents.

When the coolant leaks substantially, the fault is naturally obvious. However, the key to the problem is how to diagnose the corrosion inside the hose without disassembling it. The following method can quickly and accurately find the coolant hose that is about to be scrapped. Knead the hose with your hands, especially the hoses on the upper part of the radiator, bypass, manifold, valve body and heater. The connection end is the top priority. If the kneaded part feels obviously soft or lacks elasticity (relative to other parts), it indicates that the hose at that place has been severely corroded. If the mileage of the vehicle is low at this time, it is recommended to check the voltage of its cooling system. During the inspection, the negative pole of the voltmeter is connected to the ground of the battery; the positive pole is inserted into the coolant (without contact with any metal parts).

If the voltage reading is above 0.3V, a comprehensive and systematic inspection of the ground of the entire vehicle is required. At the same time, make sure that no auxiliary ground is connected to the radiator bracket. For the hose sub-channel, even if only one branch is leaking, it is wise to replace the entire coolant hose, otherwise it will only be a waste of effort and lose the big picture. Although most hoses can be installed flexibly without kinks, almost all hoses are molded because they are more suitable for compact installation spaces.

The OEM clamps for coolant hoses usually use an elastic clamp structure. The elastic clamp causes permanent compression deformation inside the hose, thereby achieving a tighter connection with uniform and continuous pressure. However, when the hose connection end is grooved or deformed, the sealing performance of the OEM elastic clamp is not as good as that of a high quality repair clamp. Repair clamps mainly include plastic shrink clamps that can continuously adjust the clamping force and turbine auxiliary clamps with permanent tension clamps or leaf springs. The turbine sub-clamp can generate uniform pressure in the 360° direction of the circumference, and ensure the reliability of the fastening connection through the compression permanent deformation caused by compression. The superior performance of the hose clamp can not only prevent the leakage of coolant, but also greatly reduce the amount of air inhaled during the engine cooling process.

3. Automatic transmission coolant hose

Many automatic transmission cooling lines contain a part of rubber hoses. Its flow path is quite complicated, dazzling and difficult to distinguish. Once they leak, it is bound to cause the transmission assembly to fail, and during this period, the on-board warning system will not give any prompts, that is, the automatic transmission is not equipped with a coolant leakage sensor.

4. Air conditioning hose

With the application of the new environmentally friendly refrigerant R134a, the structure and material of the air conditioning hose have changed greatly. The structure of the inner rubber layer using resin, chlorobutyl rubber and EPDM has become the best combination of air conditioning hoses. The refrigerant of the automobile air conditioning system uses HFC-134a instead of CFC-12. Due to the reduced permeability of J-134a, the permeability of nylon and water is reduced, and the inner layer of the rubber hose is replaced by IIR.

5. Vacuum tube

Today’s emission control technology can monitor and compensate for the concentration of the mixed gas in real time. Even when the vacuum tube leaks, the normal operation of the emission test system can be maintained. However, if the vacuum tube is working for a long time, it will definitely cause complaints from drivers and passengers about reduced driving comfort. The vacuum tube is located between the complex and compact powertrain components, making it difficult to conduct a very simple appearance inspection, not to mention the field inspection in the hinterland. Because the vacuum tube is close to (or resting on) the exhaust manifold and the top of the cylinder, there is a potential danger.

In addition, the vacuum tube passes near the input signal tube of the exhaust gas recirculation device EGR. And pass under the battery pack along the back of the engine hood. These areas have both sharp thin iron corners and the possibility of battery acid leakage. So the vacuum tube is very easy to damage.

6. Brake hose

Due to the emergence of insurance-free cars, the increase in the working environment temperature of brake fluids and the use of high-boiling-point brake fluids, the inner rubber layer of brake hoses is currently tending to use EPDM to replace SBR. The inner and outer rubber layers of foreign brake hoses are mostly EPDM, and the reinforcement layer uses polyester, polyvinyl alcohol or rayon fibers. The inner rubber layer can be made of pressure-resistant polyamide, and the outer rubber layer uses CSPE.

7. Power steering hose

At present, the inner and outer layer materials of hoses are changing from nitrile rubber and CR to hydrogenated NBR, CSPE, chlorinated polyethylene, and acrylic rubber. The reinforcement layer is mainly made of nylon 66. The biggest requirement for turbocharger hoses is good heat resistance. At present, foreign turbocharger hoses use a full rubber structure. That is, the inner rubber layer is composed of fluororubber and heat resistant silicone rubber. The reinforce layer is high strength aramid fiber knitting. While the outer rubber layer is silicone rubber.