At this year's Bauma, Hawe Hydraulik displayed its programmable logic valve control, PLVC 8x2, that it says "enables comfortable access to complex hydraulic systems" in cranes, crane installations, construction machinery, complex lifting and hoisting installations, forestry machines, and other mobile applications.
The control allows users to program not only pressure, velocity, and acceleration processes but also complex control and actuation tasks with short cycle times. To do so, analog and digital components and those with CAN bus interfaces are interlinked, including joysticks, potentiometers, stop switches, pressure switches, rotary encoders, speed sensors, and valves.
Hawe says the I/Os on this model have been fine-tuned to the requirements of a wide variety of hydraulics systems. Thus, the device has a total of 16 proportional outputs, which can be used, among other things, to actuate eight twin solenoids for eight functions using Hawe's proportional directional spool valve, type PSL. The basic configuration includes six digital frequency inputs, as well as 11 analog inputs that switched between 0-5 V, 0-10 V, and 4-20 mA with the help of software.
An extension board can be activated if additional I/Os or a second CAN bus interface are required. Further delivery options include a real-time watch and a remanent memory for data logging that can record measured values or error events, for example.
Hawe says the PLVC 8x2 is currently in production for a number of off-highway applications, and it can be deployed as well for industrial hydraulics, such as presses and clamping hydraulic applications in machining tools.
Also on display was Hawe's variable displacement axial-piston pump, which comes with a newly designed load-sensing controller.
Type V60N is suited for open circuits in mobile hydraulics such as the ancillary drive of commercial vehicles. The new controller contains an integrated pressure limitation function allowing unusual requirements to be met with little effort. Regardless of the pump being connected to either soft, vibration-prone, or rigid and swiftly reacting systems, the controller is always easy to adjust, according to Hawe, due to its development of a special set screw that serves as the sole adjusting element for the damping and on-stroke velocity of the pump.
The adjusting screws for the pressure relief and the stand-by pressure are positioned on the controller in direction of the shaft. Even if the pump is already pre-installed, for example at the transmission of a truck, the user can still easily adjust the settings via the screws. The single-piece screen at the load-sensing input is maintenance friendly, allowing it to be cleaned and exchanged without the need for special tools.
Hawe says the special surface finish "ensures the controller's longevity, making it a good combination for the variable displacement axial-piston pump." The new controller also comes in a more compact build compared to its predecessor. Attached to the pump, it requires less height for its installation space.
Type V60N, designed according to the swashplate principle, is capable of operating pressures of up to 350 bar (5076 psi) and peak pressure of 420 bar (6160 psi). The geometric displacement is up to 110 cm3/rev, with a maximum flow rate of 240 L/min.
The combination of pump and new controller will be available in September.