Hydraulic Ram Assembly for Metal Bending Presses

Product Specifications

Technical details and manufacturing context for Hydraulic Ram Assembly

Definition

Within an industrial metal bending press, the hydraulic ram assembly is the core actuation mechanism. It consists of a hydraulic cylinder, piston (ram), seals, and mounting components. Its function is to receive high-pressure hydraulic fluid from the pump system and translate that pressure into a powerful, controlled linear stroke. This downward force is applied directly to the tooling (die/punch) to plastically deform and bend metal workpieces to the desired angle and shape. The assembly is designed for high cyclic loads and pressures. The cylinder tube is typically made of alloy steel (e.g., ST52 per DIN 2391) to withstand internal pressure, while the piston rod is often chrome-plated steel (e.g., 45# per GB/T 699) for wear resistance. Seals, commonly NBR (per ISO 1629), prevent fluid leakage and are selected based on operating temperature and fluid compatibility. The bore diameter, stroke length, and operating pressure determine the force capacity (Force = Pressure × Area). For example, a bore diameter of 50–200 mm and operating pressure of 1.0–1.6 MPa yield a force capacity of 50–500 kN. The assembly operates within a temperature range of -20°C to 80°C, and surface roughness of the piston rod (Ra 0.2–0.4 µm) is critical for seal life and friction. When selecting or verifying a hydraulic ram assembly, confirm the bore diameter, stroke length, operating pressure, and force capacity against the specific press application. Verify that the cylinder tube material, piston rod material, and seal material meet the required standards (e.g., ISO 6020-2, DIN 2391, GB/T 699, ISO 1629). Check the maximum pressure rating (2.5 MPa) to avoid permanent deformation. Ensure the operating temperature does not exceed 80°C to prevent seal degradation. The cylinder weight (15–120 kg) affects handling and mounting design. Always consult the legal manufacturer or supplier to confirm model-specific values and compliance with applicable standards.

Working Principle

Hydraulic fluid, pressurized by a pump, is directed into the cylinder chamber behind the piston. The pressure acts on the piston's surface area, generating a force (Force = Pressure × Area). This force pushes the piston rod (the ram) outward in a linear stroke. The stroke's direction, speed, and force are controlled by hydraulic valves. Seals prevent fluid leakage, and the assembly is designed to withstand high cyclic loads and pressures.

Common Materials

Alloy Steel, Chrome-plated Steel

Technical Parameters

Parameter	Typical range	Notes & selection driver
Bore Diameter	50–200 mm	Determines force output at given pressureISO 6020-2
Stroke Length	100–500 mm	Defines maximum displacement of ramISO 6020-2
Maximum Pressure	2.5 MPa	Exceeding may cause permanent deformation
Force Capacity	50–500 kN	Calculated from bore and pressureISO 6020-2
Operating Temperature	-20–80 °C	Seals degrade above 80°CISO 6020-2
Seal Material	NBR	NBR for mineral oils; FKM for high tempISO 1629
Cylinder Tube Material	ST52	High tensile strength for pressure resistanceDIN 2391
Piston Rod Material	45#	Hard chrome plated for wear resistanceGB/T 699
Surface Roughness	Ra 0.2–0.4 µm	Critical for seal life and frictionISO 1302
Cylinder Weight	15–120 kg	Affects handling and mounting design

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Cylinder Barrel Part
Houses the piston and hydraulic fluid, contains the pressure.

Material: Precision-bored Alloy Steel
Piston & Rod (Ram)
The moving element that transmits force; the rod interface is with the tooling.

Material: Hardened & Chrome-plated Steel
Piston Seals & Rod Seals Part
Prevent internal and external leakage of hydraulic fluid.

Material: Polyurethane or Nitrile Rubber
Cylinder Head & Cap Part
Seal the ends of the barrel and provide mounting points/ports.

Material: Alloy Steel

Manufacturers of Hydraulic Ram Assembly

Manufacturer profiles associated with Hydraulic Ram Assembly.

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Frequently Asked Questions

What is the function of a hydraulic ram assembly in a press?

The hydraulic ram assembly converts hydraulic pressure into linear mechanical force. It receives high-pressure fluid from the pump and pushes the ram downward to apply force to the tooling, bending metal workpieces.

What are the key parameters to consider when selecting a hydraulic ram assembly?

Key parameters include bore diameter, stroke length, operating pressure, force capacity, operating temperature, seal material, cylinder tube material, piston rod material, surface roughness, and weight. These must match the press application and be verified with the manufacturer.

What standards apply to hydraulic ram assemblies?

Relevant standards include ISO 6020-2 for cylinders, DIN 2391 for cylinder tube material, GB/T 699 for piston rod material, and ISO 1629 for seal material. These are procurement references; actual compliance must be confirmed with the supplier.

What maintenance signals indicate a problem with the hydraulic ram assembly?

Signs include fluid leaks (indicating seal wear), reduced force or speed (possible internal leakage or pump issues), unusual noises, or overheating. Regular inspection of seals and rod surface is recommended.

Data Basis

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Preliminary Technical Classification

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pressure:	Up to 300 bar (4350 psi)
flow rate:	10-100 L/min
temperature:	-20°C to 80°C
slurry concentration:	Not applicable - designed for clean hydraulic fluids only

Hydraulic Ram Assembly

Product Specifications

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Application Fit & Sizing Matrix

Reliability & Engineering Risk Analysis

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