Hydraulic cylinders Manufacturers online

Hydraulic cylinders are mechanical drive elements that generate linear movements and high forces by using hydraulic fluid under pressure.

They are particularly used where high forces are required, such as in construction, heavy industry and mobile machinery.

Below you will find an overview of the structure, mode of operation and types of hydraulic cylinders, as well as an overview of the areas of application, their advantages and disadvantages and comments on the control system:

Structure and of hydraulic cylinders:

Important components of a hydraulic cylinder:

1. Piston and piston rod: The piston moves in the cylinder tube and transmits the generated force to the working environment via the piston rod.
2. Cylinder tube: This housing contains the hydraulic fluid and the piston.
3. Seals: They are crucial to keep the hydraulic oil inside the cylinder and ensure efficient power transmission.
4. Connections: Inlet and outlet ports direct the oil in and out of the cylinder.

How hydraulic cylinders work:

The operation of a hydraulic cylinder is based on the principle of Pascal, which states that a pressure in a fluid is transmitted equally in all directions.
Hydraulic oil is fed into the cylinder by a pump, which moves the piston within the cylinder.
This piston moves the piston rod, which is guided outwards and performs mechanical work such as lifting, pushing or pressing loads.
Hydraulic cylinders usually operate at high pressures of around 100 to over 700 bar, which enables very high performance compared to pneumatic cylinders.

Types of hydraulic cylinders:

There are different types of hydraulic cylinders that are used depending on the area of application and requirements:

1. Single-acting cylinders: In these cylinders, the piston is only moved in one direction by the hydraulic pressure; return is often provided by a spring or the weight of the load.
2. Double-acting cylinders: The piston is moved in both directions by hydraulic pressure, which enables better control and even force transmission.
3. Telescopic cylinders: This type of cylinder consists of several nested cylinder tubes and achieves very long strokes, which is ideal for applications with limited space.
4. Differential cylinders: These have different piston surfaces on either side of the piston and offer variable forces depending on the direction in which they are operated.

Use of hydraulic cylinders:

Hydraulic cylinders are widely used in industrial, mobile and heavy duty applications, especially where high force is required. Examples of applications include:

1. Construction machinery:
Hydraulic cylinders control the movements of excavator arms, shovels, bulldozers and cranes.

2. Agriculture:
They are used in tractors, combines and other agricultural machinery to generate plowing and lifting movements.

3. Industrial presses:
In manufacturing and metalworking, hydraulic cylinders are used to control presses and punches where they require extremely high forces.

4. Conveyor technology:
They move and position heavy loads or control lifting platforms and freight elevators.

5. Automotive industry:
Hydraulic cylinders are frequently used when lifting vehicles in workshops and in manufacturing processes.

Advantages of hydraulic cylinders:

• Hydraulic cylinders generate high forces and can move heavy loads precisely and reliably.
• The speed and position of the piston can be easily controlled, which is crucial in many applications.
• Hydraulic cylinders are robustly built and function reliably even under extreme loads.

Disadvantages of hydraulic cylinders:

• Maintenance is more complex than with pneumatic systems, and hydraulic fluid leaks can occur, which is particularly problematic in sensitive environments.
• Hydraulic systems require more space for the pump, lines and oil reservoir than pneumatic or electric drives.
• Hydraulic systems are more expensive to purchase and require expensive materials and precision parts.

Control of hydraulic cylinders:

The movement and force of a hydraulic cylinder are regulated by control valves that control the oil flow and pressure. these are commonly used:

• Directional valves control the direction of movement (extension or retraction of the piston).
• Pressure valves regulate the maximum operating pressure and protect the system against overpressure.
• Flow valves influence the speed of the piston by controlling the amount of oil flowing into the cylinder.
• In addition, position sensors and pressure sensors can support monitoring and control to improve accuracy and safety.

Hydraulic cylinders are indispensable drive components in heavy-duty technology and industrial applications that require high forces. They provide reliable power transmission and enable precise control even under high loads and extreme conditions. By selecting the right cylinder type and the right control unit, a wide range of requirements can be efficiently implemented.

Below is an overview of the most important points to consider when purchasing hydraulic cylinders:

When purchasing hydraulic cylinders, there are numerous factors to consider to ensure that the cylinder meets both the technical requirements and the conditions of the operating environment.

• Single-acting cylinders are suitable for applications where the piston is only moved in one direction under pressure, whereas double-acting cylinders can be moved in both directions by hydraulic pressure.
• Telescopic cylinders are advantageous for applications that require a particularly large stroke in a confined space, as they can be extended in several stages.
• These generate a different force depending on the direction of travel and are suitable for special applications in which the pressure side is used variably.
• It influences the maximum force that the cylinder can generate. A larger diameter enables a higher force output.
• A thicker piston rod ensures stability and resistance, especially with large loads or high lateral forces.
• The stroke, i.e. the length of the piston movement, must match the application. It should be neither too short nor excessively long to avoid unnecessary wear and costs.
• The cylinder must be designed for the pressure used in the hydraulic system. Standard pressures are between 100 and 700 bar, but can also be higher in special applications.
• The required force is determined by the combination of pressure and piston area. This calculation is essential to ensure that the cylinder can lift or move the load.
• Depending on the application, the cylinder can be made of different materials such as steel, stainless steel or special alloys. Stainless steel is particularly suitable for corrosive environments, while coated steel is sufficient for general applications.
• An additional coating (e.g. hard chrome for piston rods) protects the cylinder against corrosion and wear and increases the service life, especially in outdoor or industrial applications.
• Seals should be adapted to the operating conditions, such as extreme temperatures, chemical stress or high pressure. High-quality seals (such as PTFE or polyurethane) are more durable and reduce the risk of leaks.
• Seals should be easily accessible and simple to replace in order to minimize downtime and maintenance costs.
• Depending on the location, the cylinder may require different mounting points, such as foot mounting, flange, eyebolts or spherical bearings. It is important to choose the right mounting method to distribute the load optimally and position the cylinder stably.
• Hydraulic cylinders can be connected to the hydraulic system via various connection types, e.g. threaded connections or flanges. Compatibility with the existing lines and valves should be checked.
• Cylinders must be designed for the temperature ranges of the environment and the hydraulic oil, especially in extreme heat or cold conditions.
• For outdoor use or in corrosive environments (e.g. salt water, chemicals), the cylinder should be protected against corrosion, e.g. with a stainless steel design or special coatings.
• In dusty or dirty environments, protective caps and additional filters extend the service life of the cylinder as they prevent impurities from entering the cylinder.
• Some cylinders are designed for high speeds, others for slow, controlled movements. The desired speed should be in harmony with the valves and the system flow.
• For applications that require precise positioning, a cylinder with good guidance and minimal play should be selected, possibly supported by position sensors.
• Control valves regulate the direction of movement, speed and pressure of the cylinder. The choice of valves influences the accuracy and responsiveness of the cylinder.
• Sensors that monitor the position of the piston and report it back to the control system are useful for precise control. These help to control the movement precisely.
• Adjustable end position damping can ensure that the piston comes to a gentle stop and impact forces are reduced.
• Hydraulic cylinders should be certified according to recognized standards (e.g. ISO, CE), especially if they are used in safety-relevant areas.
• Good manufacturers often offer guarantees and spare parts availability. As hydraulic cylinders are often in long-term use, this is an important point.
• The choice of cylinder should be based on a balance of price and performance. Cheaper models can be more expensive to maintain and replace.
• Robust cylinders that are optimized for their intended use have lower operating and maintenance costs and require less frequent replacement or repair.
• Durable cylinders with good sealing and corrosion protection pay for themselves in the long term and lead to fewer operational interruptions.

A well-planned purchase that takes these factors into account ensures that the hydraulic cylinder meets the requirements of the application efficiently, works reliably and reduces operating costs to a minimum.

Hydraulic cylinders can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Hydraulic cylinders from all over the world can be found on Exportpages.