During Raise borer Machine operations, the manipulator is a key working component, and stable hydraulic system pressure is the core prerequisite for ensuring normal equipment operation and improving operational efficiency. In the course of Raise borer Machine construction, low hydraulic pressure in the manipulator can easily lead to deviations in operating accuracy and insufficient operational power, directly affecting the construction schedule. Based on historical after-sales cases and maintenance experience of the AT-2000 Raise borer Machine, standardized troubleshooting and handling procedures have been developed to provide a systematic reference for on-site equipment maintenance.

I. Preliminary Fault Localization: Quickly Identify the Fault Location

The first step in addressing a low-pressure fault in the robotic arm is to accurately pinpoint the location of the failure, thereby avoiding indiscriminate troubleshooting. The specific operational steps are as follows:

Disassemble the quick-connect oil inlet fitting on the small pump between the frame sections to disconnect the hydraulic links between the front and rear frames; operate the manipulator to perform its movements while simultaneously monitoring the hydraulic pressure gauge readings. The fault-location criteria are as follows: if the gauge reads approximately 20 MPa, the fault is at the front-frame end; if the gauge reading is below 20 MPa, the fault is at the rear-frame end. This rapid diagnostic step can halve the scope of the fault, significantly improving maintenance efficiency.

II. Rear frame end fault: Special inspection and handling of the pump and proportional valve

If the fault is initially determined to be at the rear frame end, the core troubleshooting should focus on two key components: the electro-proportional relief valve and the auxiliary pump, with targeted measures taken to resolve the issue:

1. Sticking Fault in the Electro-Proportional Relief Valve The electro-proportional relief valve is a critical component for controlling hydraulic pressure; accumulation of contaminants and sticking of the spool can directly result in insufficient pressure. Inspection method: Observe whether the spool moves smoothly, checking for any jamming or abnormal noises. Remedial action: Disassemble the electro-proportional relief valve, thoroughly clean the spool, valve seat, and internal flow passages to remove contaminants and oil residues, then reassemble and test to confirm that the pressure has returned to normal. 2. Small Pump Failure As the hydraulic power source, a failure of the small pump will directly cause excessively low pressure. Inspection method: Adjust the LS differential-pressure adjustment screw (the pump-start pressure adjustment screw). This adjustment must be made while the pump is running; before shutting down the pump, be sure to return the screw to its original position to prevent parameter instability. Remedial action: First clean the pump control valve to remove internal blockages and contaminants; if the pressure still does not meet specifications after cleaning, replace the small pump with a new one to ensure adequate hydraulic power output.

III. Front Frame End Fault: Comprehensive Inspection and Repair of the Valve Assembly

The pressure at the front frame end is too low, primarily due to sticking in the positioning valve and the auxiliary pump’s associated valve group; each valve group must be inspected individually:

1. Fault Diagnosis for Sticking of a Single Spool in a Positioning Valve: In multi-spool positioning valves, if a single spool becomes stuck, the result is that “the pressure for some functions is normal, while the pressure for the remaining functions is extremely low.” Inspection method: Check all functions of the positioning valve to determine whether one particular function exhibits normal pressure (with other functions at 6 MPa and the affected function at 20 MPa). Remedial action: Disassemble the solenoid directional control valve for that spool, thoroughly clean both the spool and the valve body; if sticking persists after cleaning, replace the solenoid directional control valve directly.

2. Sticking Fault in the Auxiliary Pump Associated Valve Group The auxiliary pump associated valve group affects the pilot oil pressure, which in turn leads to insufficient main system pressure. Inspection method: Measure the pressure at the downstream side of the valve group’s control port; the standard value should be around 3 MPa. Either excessively high or low pressure indicates a sticking fault in the valve group. Remedial action: Clean the faulty solenoid directional control valve and its associated stack valve group to remove oil contamination and impurities; if the valve group cannot be repaired, replace it promptly.

IV. Maintenance Summary and Prevention

It is recommended that faults caused by excessively low hydraulic pressure in robotic arms are often due to sticking of hydraulic components, blockage by contaminants, or component wear. By adhering to the principles of “locate the issue first, then troubleshoot” and “clean first, replace second,” such faults can be resolved quickly. To reduce the occurrence of these problems, three key maintenance practices should be followed on a daily basis: 1) regularly clean the hydraulic system to remove contaminants and replace the hydraulic fluid; 2) conduct routine inspections of core components such as valve manifolds and pump housings to proactively identify and address potential sticking or jamming; and 3) operate equipment in accordance with established procedures to avoid unauthorized adjustments of hydraulic parameters, thereby extending the service life of the equipment.