In hydraulic systems, proportional directional control valves provide stepless and sensitive control of pressure and flow rate. The valves allow the flow rate to be precisely adapted to the operating conditions. As a result, they ensure precise movements of hydraulic cylinders and motors - even under changing load requirements.

While classic directional control valves only change between open and closed switching positions, proportional directional control valves allow continuous regulation. This is achieved by an electrically controlled proportional solenoid, which moves the valve spool in proportion to the signal strength. This allows the speed and force of hydraulic drives to be precisely controlled.

In this article, we take a detailed look at the design, functionality and diverse applications of proportional directional control valves. Find out in which areas the valves show their strengths and what technical advantages proportional valves from ARGO-HYTOS offer.

The core components of proportional directional control valves

The housing forms the basic structure of proportional directional control valves. It accommodates all internal components and protects them from mechanical influences, contamination and pressure fluctuations. High-strength materials ensure a long service life and reliable function under extreme conditions.

At the center of the valve is the valve piston - an axially movable element that opens or closes the flow paths of the hydraulic oil. Its position determines how much fluid flows through the valve and in which direction it is directed.

The return spring ensures a safe return. It returns the piston to its starting position as soon as there is no longer an electrical control signal. As a result, the valve remains closed or open in the idle state, depending on the design.

The actual control is performed by the proportional solenoid. It generates a force that moves the spool in proportion to the applied voltage or current. The stronger the electrical signal, the further the spool moves and regulates the flow rate accordingly.

High-quality seals are integrated to ensure that the valve remains permanently tight. They prevent leaks and ensure that the hydraulic fluid is controlled in a targeted manner and without unnecessary losses.

The inlet and outlet connections enable optimum integration into the hydraulic system. Various connection configurations are available depending on the design and application.

Sensors are also used in many modern variants. They monitor the piston position or the actual flow rate and provide valuable feedback to the control unit. This data enables high-precision, closed-loop control and helps to increase the efficiency of the entire hydraulic system.

How does a proportional directional control valve work?

The control of a proportional directional control valve is a combination of electrical control, mechanical movement and precise regulation of the volume flow. In contrast to conventional switching valves, which only switch between “open” and “closed”, a proportional valve operates continuously. This allows hydraulic movements to be initiated smoothly, finely dosed and precisely controlled. This is a decisive advantage for machines that work with variable loads.

It all starts with the proportional solenoid that controls the valve. As soon as an electrical voltage or a defined current is applied, the solenoid generates a force that sets the valve piston in motion. The stronger the signal, the further the piston moves and the larger the flow cross-section for the hydraulic oil.

This precise control allows movements to be ramped up smoothly or set precisely to a certain speed.

The valve would not work without the return spring. It ensures that the piston returns to its initial position after the signal is switched off. Without it, the valve would remain uncontrolled in any position. Additional sensors, which can be optionally installed in modern valves, monitor the exact position of the piston or the current flow rate. This information is fed back to a control unit, resulting in highly dynamic, closed-loop control. The valve thus adapts to changing conditions in real time. This is an indispensable feature in modern hydraulic systems where milliseconds count.

Thanks to this ingenious mode of operation, proportional directional control valves are ideal for applications that require maximum precision and efficiency. These include, for example

• Machine tools
• Presses
• Mobile machines

Directional control valves ensure smooth, harmonious motion sequences while protecting the system from unnecessary energy loss and wear.

Where are proportional directional control valves used?

Proportional directional control valves come into their own wherever pressure and volume flow need to be precisely controlled. Thanks to various designs, intelligent control technology and optional sensor technology, they can be optimally adapted to the requirements.

One important area of application is industrial automation. In machine tools, proportional directional control valves control movements such as the clamping of workpieces or the positioning of axes with maximum precision.

Presses benefit from precise control of the pressing pressure and speed. In injection molding machines, the injection pressure and the speed of the plastic flow are precisely controlled. The valves also ensure smooth movements in assembly systems - for example when positioning robots or conveyor belts.

But the valves are not only indispensable in stationary systems. Directional control valves are also used in mobile machinery. In construction machinery, for example, they control the precise movement of excavator arms, cranes or loading shovels.

Road pavers use them for the precise control of screeds and augers to ensure even asphalt distribution. They are also used in agricultural machinery - for example when lifting and lowering attachments on tractors or harvesters. In forestry, the valves are used to precisely control cutting and gripping tools.

ARGO-HYTOS offers proportional directional control valves in a wide variety of designs - from versions with analog control electronics to valves with integrated position sensors. Depending on the application, they can be controlled directly or pilot-controlled and optionally equipped with CAN bus interfaces or internal feedback.

What makes proportional directional control valves so extremely versatile?

• They enable infinitely variable control of pressure and volume flow for precise movements.
• Their design is flexible - whether as a surface-mounted valve or screw-in valve in spool or poppet design.
• They are available in directly controlled or pilot-controlled versions and can therefore be adapted to different system requirements.
• By integrating position sensors, they can provide precise feedback on the piston position.
• With a CAN bus interface, they can be integrated into modern machine control systems.
• Their fast response time ensures immediate adaptation to control commands.
• They are suitable for a wide range of applications in industry and mobile machinery.
• Their compact design allows easy integration into existing hydraulic systems.
• Thanks to internal feedback, they are optimized for closed control loops and enable dynamic control.
• They contribute to energy efficiency by precisely controlling movements and minimizing power losses.

Optimizing your hydraulic systems together

Proportional directional control valves from ARGO-HYTOS enable precise and efficient control of hydraulic systems. Thanks to their versatility, they can be integrated into a wide variety of applications. They offer an optimum combination of performance, energy efficiency and durability. Whether in industrial systems or mobile machinery, they ensure smooth, precise movements while protecting the hydraulic components from unnecessary wear.

Thanks to continuous further development and state-of-the-art technologies, we at ARGO-HYTOS ensure that your hydraulic systems become more efficient, reliable and adaptable. The integration of sensors, CAN bus interfaces and internal feedback enables intelligent control in real time that adapts to changing operating conditions.

Would you like to optimize your hydraulic systems with innovative and powerful valves? Our experts will be happy to advise you to find the best solution for your individual requirements. Contact us and benefit from our know-how in the development of modern hydraulic technologies. We look forward to working with you to raise the efficiency and precision of your systems to a new level.