Hydraulic Hose: Function, Structure & Applications

A hydraulic hose decouples the actuator from the pump in a hydraulic system. This makes the hose assembly indispensable for applications requiring greater flexibility.

Function of the Hydraulic Hose

A hydraulic hose is the flexible connection in a hydraulic system. It is therefore the equivalent of a rigid line. Significantly higher demands are placed on the hydraulic hose than on a rigid pipe, and it must therefore possess the following properties:

• flexible in all directions
• rotatable in the couplings
• easy to replace without tools
• reliable, leak-free seal
• sufficient durability, even under demanding conditions

A hydraulic hose must respond flexibly to every movement. It must not only tolerate the swiveling and tilting movements of the actuator, but must also be insensitive to vibrations and impacts. This applies to the hose itself as well as its connection points, the couplings.

The couplings must also be rotatable. This is the only way to avoid torsion in the hose, which would otherwise destroy the flexible line sooner or later.

The coupling must be released and remounted with a single motion. Only an absolute minimum of hydraulic fluid may escape at both points.

During operation, the hydraulic hose must not come loose under any circumstances. Even in high-pressure applications, the coupling must remain absolutely tight.

The Structure of a Hydraulic Hose

To achieve these objectives, a hydraulic hose is constructed according to a specific principle. It consists of the following components:

• standard coupling on both sides
• crimped connection between coupling and hose
• multi-layer hose line made of oil- and acid-resistant rubber with reinforcement fabric

The standardized couplings match the hose size and its inner diameter. This ensures interchangeability and reduces dependence on a single manufacturer. The couplings are crimped onto the hose using a special tool. This limits the ability to manufacture or repair a hose yourself. A coupling that has been crimped once cannot be reused. Hydraulic hose tools are available commercially. However, their use should be learned and well practiced so that the self-made hydraulic hose can reliably perform its functions.

The hose line consists of several layers. The internal reinforcement fabric today consists primarily of glass or carbon fibers. It serves to withstand internal pressures of several hundred bar. The rubber of the hydraulic hose is resistant to oil and acid. This means that neither the flowing hydraulic oil nor externally impacting gasoline, machine oil, or cement can permanently damage the hose.