Walking failure is one of the common faults of excavators. Excavators often wander off, affecting construction progress and sometimes causing serious safety hazards. Listed below are several main causes of walking failures and solutions.
The output pressure of the travel proportional valve on the deflection side of the machine is too low. The travel proportional valve controls the output of the corresponding oil pressure according to the length of the control stroke of the operating handle, so that the main control valve has a corresponding movement amount, thereby controlling the speed of the working device. If the filter element of the oil filter is not replaced on time, it may cause the filter element to become clogged, causing the oil filter bypass valve to open. The dirty hydraulic oil will directly enter the circuit of the proportional valve without filtering, causing slippage in the valve. If the valve is stuck, the control oil cannot flow to the rotary main control valve through the rotary proportional valve on the deflection side of the machine, resulting in walking deviation. Therefore, the troubleshooting method is to check the pressure of the traveling proportional valve. The troubleshooting method is very simple, which is to clean the valve body and related oil circuits, and replace the hydraulic oil and filter element.
The small hole of the balance valve of the transmission system is blocked by dirt, resulting in the parking brake force being unable to relieve the excavator. When the excavator is walking, if the pressure oil cannot push the balance valve spool to move through the small hole on the balance valve, the pressure oil cannot By releasing the parking braking force through the slot on the balance valve, the excavator’s traveling motor cannot rotate normally, causing the excavator to wander. The troubleshooting method is to clean the balance valve and prevent dirt from entering during disassembly and assembly.
The sealing ring of the central rotary joint is damaged. The central rotary joint is composed of a shell and a mandrel. The shell is installed on the upper car body, and the mandrel is installed on the lower car body. The mandrel has annular grooves equal to the number of oil pipes. The hydraulic oil from the housing flows from the vertical holes on the mandrel to the traveling motor through these oil grooves. Therefore, even if the housing continues to rotate with the upper car body, the hydraulic oil on the mandrel The groove can also be kept clear of the oil port on the casing, allowing hydraulic oil to flow in and out freely. If the filter element of the hydraulic oil is not replaced in time, the bypass valve on the filter element may be opened. Since the hydraulic oil is not filtered, impurities in the oil will directly enter the sliding surface of the central rotary joint, causing damage to the sealing ring on the excavator. During walking, due to the leakage of pressure oil on one side, the speed of the walking motors on both sides is different, resulting in the machine walking off track. The troubleshooting method is to replace the center rotary joint oil seal and replace the hydraulic oil and filter element.
The above is an analysis of the walking faults of second-hand excavators. If you need to buy a second-hand excavator, you can contact us. If you need to purchase related excavator accessories during the use and repair of your excavator, you can also contact us.
Post time: Mar-28-2024