Trouble phenomenon: When a Hitachi ZX300-5A excavator performs light-weight operations such as horizontal extension of the stick, the cooperation between the stick and the boom is not good.The stick is one beat slower than the boom. During ordinary excavation operations, it feels No exception.
Fault detection:
Since the inner diameter of this hose is 5/8, it is a special size, and it is often not sold in hose shops in the street, so it is often used when the inner diameter is 1/2. Under no-load conditions, a slightly higher working pressure occurs than usual. The work sound also sounds as if it is blocked.
Maintenance:
1. Due to the damage of the cylinder hose, the customer manufactures and installs it in the street hose store. Therefore, the inner diameter of the hose is thinner than the standard (cross-sectional area). Therefore, the return side has intercepted the flow, causing the speed to decrease.
2. Trouble-shooting method: replace the hose with a regular product.
Knowledge supplement: Hitachi ZX300-5A excavator crusher impact energy drop failure analysis and maintenance
Cause Analysis:
1. The amount of oil is insufficient. The pressure of the nitrogen chamber is too low; the pressure of the safety valve is low and the oil temperature is higher than 80 ℃;
2. The back pressure of the oil is high; the deformation of the foot pedal controls the deformation of the pipeline; the hydraulic pump damages the oil pollution;
3. The control valve or related parts are faulty: the control valve is stuck; the stroke of the control valve is not enough due to the loosening of the bolt; the internal failure of the cylinder body and the entry of foreign substances.
Maintenance: Check the pipeline and dredge the oil circuit so that the back pressure does not exceed the specified value; inflate to the specified value; check and repair the valve and related parts or replace: check the cooling system, reduce the oil temperature to the working temperature; adjust the safety valve pressure to the specified value : Check the volumetric efficiency of the oil pump, and replace the oil pump if it is low; check the filter and hose for insufficient oil absorption; ask the supplier to dismantle; replace the hydraulic pump; clean or replace.
