Manufacturing Hydraulic Hoses
The hydraulic hose manufacturing process is a combination of the processes used to manufacture the constituent parts. The constituent parts of the hydraulic hose include the outer cover, the textile or metal reinforment, and the inner tube. The outer cover is designed to provide robust service and protection from elements of climate and operating conditions.
Sun, wind, heat, cold, humidity and wind all are climatic elements that can prematurely erode a hydraulic hose cover. Abrasion and vibration are the primary operating elements that can also erode and decay hydraulic hose covers. With the cover eroded, the inner reinforcement is revealed to the elements which can be very dangerous as hydraulic hose operates under very high pressure and any leak can be harmful even fatal to operators working around these hydraulic hoses.
The outer cover between hydraulic hose manufacturers can vary significantly which is important when it comes time to choose hose end fittings to build assemblies Reinforcement of hydraulic hose can come from either textile or steel. Textile reinforced hydraulic hoses are rated for lower pressures than steel reinforced hoses. Textile hoses are more flexible and cost less than steel hoses as their manufacturing process is much simpler than handling steel. The raw cost of materials is also lower for textile hoses.
Steel reinforced hydraulic hoses can handle much higher pressures than textile hoses. Steel hydraulic hoses can be either built by braiding or spiraling steel over an inner cover. Braiding utilizes braiding machines that continuously lay steel braids over one another to form long lengths of hose. Spiraling steel is more difficult than braiding and is used to form the highest pressure hydraulic hoses. Steel spirals are also more rigid than braided steel and also more expensive.
Finally, steel spiraling produces shorter lengths of hydraulic hose. The inner tube of hydraulic hoses is generally a rubber tube that is of fixed diameter (unlike the outer diameter which can vary from manufacturer to manufacturer). The inner tube must be compatible with the type of fluid that moves through the hydraulic hose. The inner tube is made of treated rubber and is generally extruded in a single large length. Most hydraulic hose manufacturing lines exist outside of North America and have moved to low cost manufacturing countries. There are still some manufactguring plants in the United States which serve mostly military customers as the government typically purchases hydraulic hose from domestic strategic suppliers.
Most of the independent hydraulic hose manufacturers have moved overseas so these manufacturing plants are typically for the larger public companies. -Types Hydraulic hose types can be broken down by their reinforcement. The breakdown is as follows: Textile – R4, R3 Braided Steel: 1SN (1 wire braid), 2SN (2 wire braid) Spiral Steel: R12 (4 spiral), 4SH (6 spiral) Other than reinforcement, the hose can have different hose covers for climate and operating conditions. Therefore these hoses will have reinforcement classifications and outer cover classifications.
For rare cases, the inner tube may also dictate classifications as the inner tube needs to handle diffferent types of fluids. -Crimping When crimping hose ends onto hydraulic hose, most manufacturers recommend matching their hose ends to their hose. However, if the hose outer diameter is the same, different brands of hose ends will work for the hydraulic hose of similar diameter. Generally, with most hydraulic hose crimpers, hose is capped with a hose end then placed into a crimper.
The crimper crimps down on the hose end which then latches onto the hydraulic hose. In the case of “bite-to-the-wire” hose ends, the hose ends actually bites through the rubber outer cover and into the hydraulic hose metal reinforcement. There are a few crimper manufacturers in the US however Custom Crimp is the largest. Other manufacturers exist in Europe as well as in Asia.