When the bucket is slow in excavation, the excavator's construction efficiency is greatly reduced, so the similar conditions once occurring must be promptly handled with. Because fault would cause large problems even if the construction speed would be reduced greatly.
Today, the shearing engineer will share detailed fault maintenance process with everyone as per the slow excavation speed of bucket.
Firstly, it is necessary to confirm that only the bucket has slow speed or other actions are slow. If it's the former reason, the diesel engine could run as per rated rotation speed, operate the pilot valve for overflow of big cavity of bucket, then grasp the oil outlet that two multi-way valves lead to big cavity of bucket oil cylinder with both hands to observe whether the following conditions occur:
The first condition: Two high-pressure oil pipes have the sense of oil flow, indicating that the big cavity of bucket has confluence.
The excavation speed of bucket is slow may due to the following reasons
1. The secondary overflow valve of bucket big cavity is too low in overflow pressure value. At this time, the pressure gauge is installed at the oil outlet of hydraulic pump so that the excavation of bucket is at the overflow status.
If the display value of pressure gauge is very low, the secondary overflow valve of bucket big cavity shall be adjusted. If the pressure value changes, the overflow pressure value could be adjusted and increased to the rated pressure value. If the pressure value of secondary overflow valve after adjustment keeps unchanged, the reasons are as follows in general:
● The spring of secondary overflow valve is snapped or yielded, so the damaged spring shall be replaced;
● The foreign matters are stuck between valve core and valve core seat and the overflow valve has early overflow, so the sundries need to be cleaned up.
2. The piston seal of bucket oil cylinder is damaged or severely worn, so the piston seal shall be replaced.
3. The piston rod bends, so it shall be calibrated, amended or replaced.
The second condition: If only one high-pressure hose has the sense of oil flow, there isn't confluence in big cavity of bucket. It is necessary to continue checking as per the following methods:
1. If there is not sense of oil flow when the valve group leads to the bucket big cavity, the reasons may be as follows:
● Valve rod has been bonded or be stuck by foreign matters, it is necessary to match the grinding valve rod and valve hole or eliminate foreign matters for the free reversing of valve rod.
● The pilot control oil pressure is low, which couldn't make the complete reversing of valve rod. It is necessary to eliminate the fault due to excessive low pilot control oil pressure;
● If the foreign matters are stuck in the corresponding pilot control tube, they shall be promptly eliminated.
2. If the oil outlet that valve group II leads to bucket big cavity has no sense of oil flow, two and three-teeth thread of pipe joint for the corresponding valve rod to control oil way could be loosened, and the operation handle of bucket big cavity is operated and controlled by gradually increasing the operation angle and observing whether the loose position of pipe joint leaks oil or sprays oil:
● If the loosened pilot tube joint leaks oil, the multi-way valve rod has no pilot reversing pressure or the reversing pressure is very low because the valve core of reversing valve is poor in finishing degree, corrodes or is stuck by foreign matters. The valve core of reversing valve shall be dismantled and replaced, the sundries and foreign matters shall be cleaned up.
● If the loosened pilot guide joint sprays oil, multi-way reversing valve rod has the pilot reversing pressure probably because the multi-way reversing valve rod has been bonded or are stuck by foreign matters. The rod shall be repaired or the foreign matters are eliminated the free reversing of multi-way reversing valve rod.