Hydraulic hose assemblies – the critical links formed by combining flexible hose and metal fittings – are fundamental to power transmission in countless industrial and mobile applications. Understanding their classification, primarily by working pressure range and connection method, is vital for system safety and performance.
Classification by Working Pressure Range
1. Low Pressure (Below 3 MPa / ~435 PSI):Primarily utilizes hoses reinforced with fabric (cotton/fiber) braids. Common applications include control circuits, automotive brake lines, and some hydraulic machine tools.
2. Medium Pressure (3-10 MPa / ~435-1450 PSI): Dominated by hoses featuring one or two layers of steel wire braid, typically in larger diameters. These are widely used in medium-to-low pressure supply lines and return lines.
3. High Pressure (10-31.5 MPa / ~1450-4570 PSI): Employs robust constructions like one, two, or three-layer steel wire braided hoses or steel wire spiral (wound) hoses. This is the standard range for core high-pressure hydraulic systems.
4. Ultra-High Pressure (Above 31.5 MPa / ~4570 PSI): Primarily utilizes steel wire spiral hoses, generally in diameters of 31.5mm and below. Demand for these assemblies is rapidly increasing with the advancement of ultra-high-pressure, high-power hydraulic machinery.
Classification by Connection Method: Crimped vs. Reusable
The secure attachment of the fitting to the hose is paramount. Two primary methods exist:
1. Crimped Assemblies:
Process:The pre-assembled hose and fitting are permanently joined by applying significant external force. This cold-forming process radially compresses the fitting’s outer sleeve (ferrule), biting securely into the hose reinforcement.
Advantage:Proven reliability and consistent, leak-free performance under pressure and vibration. This is the preferred and most widely used method by professional manufacturers globally.
2. Reusable (Screw-Together) Assemblies:
Process:The fitting features an internal, tapered core (mandrel) that compresses the hose’s inner tube against a matching tapered socket within the outer sleeve as the assembly is tightened.
Consideration: While offering field reassembly potential, this method can suffer from less consistent connection integrity and stability compared to crimping, particularly under demanding conditions.
Industry Standardization and Safety
The clear classification by pressure and connection type is essential for safe system design,” commented an industry engineer. While reusable fittings offer convenience in specific scenarios, the crimped connection remains the gold standard for reliability in high-pressure hydraulic applications due to its consistent, high-integrity bond. Specifiers and maintenance personnel must always refer to manufacturer ratings and industry standards (like SAE J517) when selecting hose assemblies.”
The ongoing trend towards higher system pressures, especially in mobile and industrial equipment, continues to drive innovation and demand for high-performance, reliably connected ultra-high-pressure hose assemblies.
**About Us:**
Hainar Hydraulics is a leading provider of fluid power solutions, specializing in high-quality hydraulic hose assemblies, fittings, and related components for industrial and mobile markets. We prioritize safety, reliability, and performance.
Post time: Jun-13-2025