6/2 Hydraulic Solenoid Valves – Advanced Working Flow Dividers

6/2 hydraulic solenoid valves, classified in engineering nomenclature as six-way, two-position spool valves, are advanced components designed for precise and trouble-free management of working fluid flow in hydraulic power systems. These devices function as electromagnetic twin dividers. They allow for alternating supply and control of two independent actuators (e.g., two double-acting cylinders or hydraulic motors) using only one existing section of the main control valve. An electrical signal sent to the solenoid immediately shifts the internal spool, redirecting the pump flow to the second working circuit. This solution eliminates the need for physical expansion of the control valve block with additional mechanical sections, which drastically reduces the system's own weight, simplifies the routing of pressure lines, and minimizes energy losses caused by pressure drops.

Application and Technical Characteristics

The design of 6/2 solenoid valves is based on a monolithic body cast from high-strength ductile iron or specialized heat-treated steel. These materials guarantee full structural rigidity and resistance to pressure peaks reaching up to 210-350 bar in the main ports, depending on the chosen model and connection diameter. A precisely fitted, ground, and honed spool-body pair reduces internal edge leakage to an absolute minimum. This allows for stable maintenance of the actuator's working position even under maximum static load.

These components are fully adapted for operation with mineral hydraulic oils of classes HL, HLP, and HVLP, in accordance with ISO 6743/4 guidelines. Proper fluid characteristics are of primary importance for system efficiency. For this purpose, only clean, high-quality hydraulic oil with optimal kinematic viscosity should be used. A wide range of permissible operating temperatures (from -25°C to +90°C) enables trouble-free operation of machines in extreme environmental conditions. Solenoid coils, standardly mounted with an ISO 4400 (DIN 43650) plug connector, are characterized by insulation class H and protection rating IP65, which protects the electrical system against the ingress of moisture, dirt, and dust.

Main implementation areas for 6/2 solenoid valves:

• Construction machinery: Control of additional working attachments (the so-called third section) in mini-excavators and loaders – operating grapples, bucket tilt, or quick couplers.
• Agricultural and forestry machinery: Expansion of the functionality of front loaders (TUR), plow rotation, sprayer booms, and timber grapples, where hydraulic control valves require multiplication of output lines.
• Transport and specialized vehicles: Systems for switching power between the main circuit of HDS cranes and hydraulic stabilizer outrigger legs.

To maintain the full service life of internal spool fits, protection against solid contaminants is a priority. A correctly installed hydraulic filter with the appropriate micron rating effectively eliminates the risk of spool seizure.

Product range classification by supply voltage

For optimal integration with the electrical systems of machines and vehicles, the 6/2 solenoid valve category is divided into two basic supply groups. The choice of the appropriate solenoid coil voltage is determined by the technical specification of the alternator or battery of the host machine.

1. 6/2 Solenoid Valves – 12V DC Supply

Dedicated to low-voltage systems commonly used in agricultural tractors, municipal machines, delivery vans, and smaller construction equipment (e.g., mini-excavators). 12V DC coils are characterized by higher current consumption at a given rated power. This requires the use of appropriately sized electrical cables to prevent voltage drops on the supply line.

2. 6/2 Solenoid Valves – 24V DC Supply

Designed for heavy industrial applications, trucks, forestry machinery (harvesters, forwarders), and large construction equipment. Due to the higher rated voltage, these coils draw half as much current (amperage) as 12V versions of the same magnetic power. This limits heat generation in the control circuit, minimizes energy losses, and allows for the implementation of wiring with a smaller cross-section, which is standard in industrial installations and heavy vehicles.

Why choose our components? Technical benefit

The 6/2 solenoid valves offered at the Hydron store are manufactured in compliance with rigorous DIN and ISO standards, which guarantees full geometric and material repeatability. Working ports (internal BSP inch threads) are cut according to the ISO 228/1 specification, preventing body deformation during assembly. All solenoid coils feature an ED 100% duty cycle (continuous operation mode), which eliminates the risk of solenoid overheating during long-term power supply. Furthermore, the valves are equipped with a mechanical emergency override pin, allowing manual spool shifting during maintenance work or in the event of a sudden power loss in the machine.

Technical specification comparison table

Frequently Asked Questions (FAQ)

1. Can a 12V coil be replaced with a 24V coil on the same 6/2 solenoid valve body?
Yes, in most professional spool valves, the mechanical design of the body and the solenoid tube (the so-called coil stem) is fully standardized. This means that the hydraulic parameters of the valve do not depend on the control voltage. If you are upgrading the machine's electrical system from 12V to 24V, simply remove the locking nut, slide off the old coil, and install the new 24V component, while keeping the same hydraulic body.

2. What are the consequences of the supply voltage dropping below the rated value?
The value of the magnetic force generated by the coil is directly dependent on the supplied current. If the voltage in the control circuit drops below the permissible tolerance (usually below 10% of the nominal value, i.e., <10.8V for 12V systems and <21.6V for 24V systems), the solenoid will not generate enough pulling force. As a result, the spool will not overcome the resistance of the internal return spring and the hydrodynamic pressure of the oil flow, which will lead to incomplete switching of the channels, flow throttling, increased medium temperature, and incorrect operation of the actuators.

3. When is an external drain line installation required for 6/2 solenoid valves?
Connecting the external drain port directly to the oil tank becomes technically necessary when the back pressure in the return lines exceeds the permissible mechanical strength of the spool sealing chamber (most often this threshold is between 25 and 50 bar). A lack of drainage under high back pressure conditions will cause a hydrostatic lock of the spool – the fluid accumulated in the spring chambers will prevent the solenoid from moving the spool, and in extreme cases, will lead to the solenoid seals bursting.

4. How to choose the flow rate of a 6/2 solenoid valve (50, 60, 90 or 140 l/min) for the system?
The selection of the flow parameter must be strictly correlated with the maximum output of the hydraulic pump supplying the given line, and not with the cylinder capacity. If the system's nominal output is, for example, 75 l/min, a valve with a capacity of up to 90 l/min should be chosen. Using a valve that is too small (e.g., 50 l/min) will cause a rapid increase in flow resistance and a massive pressure drop, leading to cavitation, oil foaming, and rapid overheating of the entire hydraulic system.