In heavy machinery and industrial fluid power systems, hydraulic hoses play a vital role. As flexible pipelines, they carry hydraulic fluid – the core medium of the system – to drive the operation of excavators, factory presses, and various equipment that generates powerful force. However, hoses vary greatly in performance. Choosing inappropriate reinforcement layers or material specifications may result in sudden failure, safety hazards, and expensive production downtime. To ensure stable performance and long service life, engineers and maintenance technicians must select products based on strict standards, reinforcement structures, and pressure ratings.

From high‑pressure spiral‑wire lines to low‑pressure return lines, the key to selection is matching hose structure with actual working demands. Below are the most common types of hydraulic rubber hoses and their typical applications.

For hydraulic systems that require extremely high pressure, hoses must have strong pressure‑bearing capacity. DIN EN 856 4SP and 4SH hoses are designed for such heavy‑duty conditions. Both types use an oil‑resistant synthetic rubber inner tube, reinforced with four layers of high‑tensile steel wire spiral winding, and are covered with a protective outer layer resistant to oil, weather, and abrasion.

These hoses are widely used in heavy construction and mining equipment. They are compatible with many hydraulic fluids, including mineral oils, glycols, and emulsions, and can operate continuously at temperatures from −40°C to +100°C. The main difference between 4SP and 4SH lies in steel wire design and diameter, which determine their respective pressure ratings. In applications with frequent high‑impact pressure cycles, spiral‑wire hoses are more durable than braided hoses and better resist fatigue damage.

While spiral‑wire hoses handle the heaviest loads, most hydraulic systems rely on wire‑braided hoses. SAE 100 R1 (1SN) and SAE 100 R2 (2SN), consistent with DIN EN 853, are global standard products for medium‑ to high‑pressure systems.

SAE 100 R1 AT / 1SN has one layer of steel wire braid reinforcement, with a working pressure range of 40 to 250 bar. It is versatile and commonly used in general industrial machinery and mobile equipment under moderate pressure.

SAE 100 R2 AT / 2SN has two layers of steel wire braid, nearly doubling the pressure resistance up to 415 bar, making it suitable for more demanding hydraulic circuits. Both types feature an oil‑resistant inner tube, weather‑resistant cover, and wide temperature tolerance.

A key advantage of modern R1 and R2 hoses is no‑skive fitting compatibility. With fittings such as DPF4T ferrules and DPX4XX inserts, they can be assembled quickly and reliably without removing the outer cover, maintaining structural integrity and improving installation efficiency. For mining and other high‑safety industries, these hoses often meet strict flame‑resistance standards, including MSHA (US) and MA (China) approvals, allowing safe use in hazardous environments.

Not all hydraulic circuits require extremely high pressure. Low‑pressure return lines, pilot lines, and some lubrication systems need more flexible and economical solutions. SAE 100 R3 and R6 textile‑braid hoses are ideal for these conditions.

SAE 100 R3 uses an oil‑resistant synthetic rubber tube with two layers of high‑tensile textile braid. It offers good flexibility and adequate strength for low‑ to medium‑pressure lines, often used in mobile equipment that requires tight bending and vibration resistance.

SAE 100 R6 provides even greater flexibility with one layer of textile braid. As the most flexible standard hydraulic hose, it is compact and well‑suited for return lines and cramped installations.

Both R3 and R6 hoses operate within −40°C to +100°C, with oil‑, weather‑, aging‑, and ozone‑resistant covers. Despite their lighter structure, they deliver reliable service life and are specially designed for conveying mineral‑oil‑based hydraulic fluids in non‑high‑pressure systems.

Whether it is a heavy‑duty DIN 856 4SH hose driving a rock crusher, a versatile SAE R2 hose operating a press, or a flexible SAE R6 hose installed in a tight return line, each type is a precisely engineered component. Understanding the structure – from the oil‑resistant inner tube to the specific reinforcement layer – is essential for safety and efficiency. By choosing the right hose based on pressure, temperature, and fluid requirements, you ensure consistent and reliable performance for your machinery.