Hydraulic Pressures of Mini Diggers: How Do They Work?

27 September 2018

Thanks to the litres of uncompressible hydraulic fluid coursing through their compact mobile frames, mini diggers can perform extraordinarily laborious tasks. Imagine, then, a mini excavator that, for some incomprehensible reason, didn’t use hydraulic technology. It wouldn’t be compact any longer, that’s for sure.

A Purely Mechanical Mobile Lifter

The clanking, rumbling mini digger makes its way on-site. Only, it’s neither “mini” nor much of a digger. It moves slowly, pauses to change gears, then there’s a terrible ratcheting sound as gear chains and sprockets catch. Instead of a nimble pirouette around a site obstacle, the mechanics-only machine takes minutes to circumnavigate the hindrance because the poor operator is trying in vain to steer this underpowered behemoth.

Hydraulic Pressures of Mini Diggers

Fortunately, that equipment only exists in the realms of fantasy. It was a hypothetical mobile digger, one that blinked out of existence when the real deal rolled into position. This is a true mini digger, a compact group of actuators, pumps, reservoirs, and valves, which manipulate hydraulic fluids. As they’re manipulated, the digger’s heavy attachment moves. It only takes a few flicks of a joystick to control this movement. Under the hood, that mostly uncompressible fluid begins its journey in the pilot hydraulics circuit, which opens and closes the system actuators. Meanwhile, away from the pilot lines, the main hydraulic lines receive their pressurized loads from a primary pump. For mini diggers, one, perhaps two pumps get the job done. For larger excavators, however, we could be looking at a total of three hydraulic pumps or motors.

Auxiliary and Primary Equipment Pumps

The second pump is responsible for the auxiliary hydraulic systems. It operates synchronously alongside electronic control systems. Mainly, for this hydraulic pressures category at least, the fluid generates responsive and reliable control signals. For the primary lines, though, they’re tasked with more. Main hydraulic lines, and this explanation applies to mini diggers, too, have to squeeze their pressurized oils through small-diameter tubes and hoses. High operational temperatures are experienced here when this system isn’t optimally primed.

Responsive and ready to carry out poised movements in a split-second, the hydraulic pressure in the pilot system is properly set. The bucket responds to every twist of the operator joystick. Just as importantly, the force produced by the primary lines is there, in the system and ready to move an oversized, overweight load. If the controls feel spongy, check the pilot circuits. Alternatively, if the mini digger is flagging somewhat and feeling underpowered, make sure the primary hydraulics lines are clear, the actuators and bucket pistons are fully powered, and the system pumps are functioning.