Rubber hydraulic hose is a common and important element in countless industrial and mobile machines. It serves as the plumbing that routes hydraulic fluid between tanks, pumps, valves, cylinders and other fluid-power components. Plus, hose is generally straightforward to route and install, and it absorbs vibration and dampens noise. Hose assemblies—hose with couplings attached to the ends—are relatively simple to make. And if specified properly and not overly abused, hose can work trouble-free for hundreds of thousands of pressure cycles.
Rubber hydraulic hoses are used for power transmission and control in hydraulic systems. Designed for hydraulic oil, working temperatures from -40 to +100°C and working pressure till 420 bar (42 Mpa).
Due to its construction, hydraulic hoses can be divided into following categories:
Hoses with textile braid (one or two layers).
Hose with one or two layers of steel wire braid (one, two and three layers).
Hoses with spiral wire braid (four or six layers).
The inner tube contains the fluid and keeps it from leaking to the outside. The type of hydraulic fluid generally dictates the tube material. Usually it is nitrile or synthetic rubber for petroleum-based hydraulic oil. But alternatives like Viton or Teflon are used with synthetic fluids like phosphate ester.
The cover protects the reinforcement layer. One consideration when determining the cover material is resistance to attack from outside influences like chemicals, salt water, steam, UV radiation and ozone. Common cover materials include nitrile, neoprene and PVC, among others.
Braided steel-wire hose comes with one or two reinforcement layers. When two layers are used, a rubber layer separates the two. Common types, such as widely used SAE 100R1 and 100R2 versions, are often referred to as “1-wire” and “2-wire” hose, respectively. These products are considered medium-pressure hoses, for use from about 1,000 to 5,000 psi—depending on the number of reinforcement layers and the size. They are used on many types of industrial machinery and construction equipment, as well as on heavy-duty trucks and fleet vehicles.
Spiral-wound hydraulic hose is for demanding, high-pressure applications, generally from about 4,000 to 8,000 psi. They have alternating, tightly wound spiral layers of high-tensile steel wire. The wires in the second layer are laid at an opposing angle to the first, and the pattern repeats for each subsequent layer.