7 t - 12 t
1x HPR 105-02 E1L + 1x HPV 75-02 E2
2x VW14M3 (directional control valves monoblocks)
2x CMV 60 E600 (travel circuit pump)
1x iCon (electronic control unit)
- Most compact dimensions of hydraulic components
- High performance electronic controller for simultaneous actuation of open and closed circuits
Walking excavators – also known as spider excavators—are extremely specialized construction machines that move forward on four wheels, which are connected to the undercarriage by legs.
These legs can also be used to adjust the track width and the height of the vehicle over a wide range of dimensions, ensuring that the machine is highly flexible and can be adapted to the surrounding conditions, both in drive mode and work mode, when the stabilizers on the legs are extended. This means that they are ideally suited to work in locations such as very steep slopes or in mountain streams.
Exploiting this great degree of freedom in usage not only requires a very skilled and experienced driver, but also a powerful hydraulic system that can execute the often superimposed movements with the necessary dynamics or sensitivity.
The work hydraulics here are configured as a complete system of Linde Hydraulics components, including the electronic control unit.
Supply via tandem pump unit
At the core of the hydraulic system is a tandem pump unit. A load-sensing regulating pump HPR 105-02 E1L for the open circuit supplies the work hydraulics with hydraulic fluid, while an HPV 75-02 E2 variable displacement pump for the closed circuit drives the traction motors.
The two pumps can be used in tandem configurations and have a special housing with an SAE clutch bell. This way they save space in the machine room where every centimeter counts. The motors of the drive unit are also exceptionally space saving: the plug-in housing means they are positioned directly at the wheels, ensuring smooth driving.
Social load sensing
The system is controlled via a compact LSC monoblock, in which three directional control valves are integrated in a single cast housing. The pressure relief function is also integrated in the monoblock, and special functions can be implemented using an intermediate plate. The valves have a flow-optimized design and feature integrated pressure compensators and pressure copiers.
The special features of the LSC system include its “social load sensing” capability. This is a special kind of volume flow regulation for superimposed movements, which are frequently required for walking excavators. The relevant functions are supplied as required depending on how the driver moves the joystick, even if the requested flow volume exceeds the maximum possible pump flow rate. In this case, the available flow is divided amongst the functions depending on their requirements.
Complete system with electronic control unit
The electronic control unit of this machine deserves particular attention since it controls the key functions in the open circuit as well as the drive components of the closed circuit.
It also comes from the Linde Hydraulics modular system. It maps the complete drive hydraulics and work hydraulics of the new machine. The software developers at Linde have implemented some additional functions in the electronic control unit, including the option to select pre-configured drive programs, such as an “eco mode” where the walking excavator operates in a particularly energy-efficient manner.