Hydraulic hose fittings are key components that connect hoses to components in hydraulic systems. They come in a variety of types and can be categorized into the following common types based on structure, function, and standards:
1. Classification by Connection Method
Crimped Fittings
Crimped fittings permanently secure the fitting to the hose using a crimping tool. They offer excellent sealing and are resistant to high pressures. They require specialized equipment for disassembly and are commonly used in industrial applications.
Reusable Fittings
Assembled using threads or clamps, they are reusable and easy to repair, but have lower pressure-carrying capacity.
2. Classification by Thread Standard
Metric Threads
For example, the M series (M12×1.5) is commonly found in European and domestic equipment.
Inch Threads (UN/SAE)
UNF (fine thread): For example, 9/16"-18, used in American standard systems.
NPT (tapered pipe thread): Features a sealing taper and requires sealant or teflon tape (for example, 1/4" NPT).
BSP (British Standard): BSPP (parallel, such as G1/4) and BSPT (tapered, such as R1/4).
3. Common Connector Types
Flange Connector
Bolted, high-pressure resistant (such as SAE flanges), used in high-flow engineering machinery.
Quick Coupling Connector
Equipped with a self-sealing valve for quick disconnection, available in flat seal (such as ISO 16028) and ball valve types.
O-Ring Sealed Connector (ORFS)
With an O-ring on the end face (SAE J1453), it offers excellent leak resistance and is suitable for use in vibrating environments.
37mm Flared Joint (JIC)
37mm Cone Metal Seal (SAE J514), commonly used for medium and high pressure applications.
24mm Cone Connector (SAE)
24mm taper (such as SAE J512), used in low-pressure or fuel systems.
Bite-Type Fittings
Use a ferrule to engage rigid tubing, eliminating the need for welding and making installation easy.
4. Classification by Function
Straight Fittings
Connects two coaxial ends.
90/45 Elbows
Changes the direction of a pipe.
Tee/Cross Fittings
Used for dividing or combining flows.
Reducers
Connect pipes of different diameters.
5. Other Special Fittings
Rotary Fittings
Allows relative rotation of pipes to prevent torque damage.
Adapters
Converts between different standards or genders (e.g., male to female threads).
Selection Considerations
1. Pressure Rating: Matches the system operating pressure (e.g., 3000 PSI and above requires a high-pressure design).
2. Media Compatibility: Consider the effects of oil and temperature on the sealing material (e.g., NBR, FKM, etc.).
3. Installation Space: Elbow angles and connector lengths must be adapted to the layout.
4. Standards Compliance: ISO, SAE, DIN, etc., to ensure interchangeability.