Created on:2021-07-14 10:51

Hydraulic failure of mg57idw AC haulage shearer

Hydraulic failure of mg57idw AC haulage shearer

Mg57idw AC haulage shearer is developed by a coal machinery factory on the basis of absorbing the advanced technology of electric haulage shearer at home and abroad. It uses electric traction unit instead of hydraulic traction unit and adopts computer control technology. It has the characteristics of high reliability and advanced performance. It is an ideal machine for comprehensive mechanized coal mining in medium and thick coal seam at present.

(1) The cutting part is short of oil

① Cause analysis in order to prevent the oil from flowing back to the bottom oil pool when the shearer is cutting the top cutter, causing the damage of the internal transmission parts, the shearer adopts the separate cavity lubrication structure in the deceleration cavity of the cutting part, and uses the isolation oil seal to separate the cutting part into two lubrication cavities, the planetary gear cavity and the spur gear cavity, and the two oil pools are not connected with each other. Because the planetary gear cavity has a transmission shaft extending, oil leakage is easy to occur, and the oil filling hole is M30 × 2 mm screw hole, and the viscosity of N320 gear oil injected into the cavity is high, so it is difficult to inject oil, which makes the lubrication cavity short of oil and causes damage to the cutting part.

② On the basis of the original oil injection hole, + 25mm high pressure pipe joint is added and connected with the external oiler to form a static pressure oil injection device. At the same time, a vent plug is set on the cavity wall to ensure that the air in the cavity is discharged in time, reduce the oil injection resistance and ensure the oil injection effect. With this method, the oil injection can reach 15L / h. even if the transmission shaft leaks oil, the oil injection can meet the lubrication needs. In addition, because the static pressure oil injection device adopts a separate structure, it is connected when in use and removed when cutting coal, so it is very convenient to use, which completely eliminates the damage accident of cutting part caused by lack of oil.

(2) Frequent braking of traction part

① Cause analysis in order to prevent the shearer from sliding when the inclination angle of the working face exceeds 20 degrees, a hydraulic brake is installed on the operating side of the traction motor spindle. When the motor stops, the brake stops; When the shearer is working, when the motor rotates, the brake should be released. But in the actual work, because the brake and the traction motor control circuit is not synchronized, the traction motor has been powered and the brake can not be opened, or vice versa. This causes the brake to brake frequently and burn the traction motor in serious cases.

② Elimination method and structure improvement most of the coal mines are gently inclined coal seams, and the dip angle of coal mining face is mostly below 12 ° without braking, so the motor and brake are divided into two parts. Usually, only the motor is installed and the traction is normal. When the inclination angle of the working face is greater than 20 degrees, install the brake again. This solves most of the problems.

(3) Hydraulic system failure

① The reason analysis shows that the height adjustment system of shearer is two sets of hydraulic devices with the same shape and structure, which realize the lifting of left and right cutting parts respectively (see Fig. g for the principle). The control valve of the system adopts three position four-way electromagnetic directional valve. Due to the large resistance of armature reciprocating motion in the work, it is difficult for the valve core to move when the power is on, which makes the cutting difficult to lift and affect the normal production.

② The elimination method and structure improvement redesign the height adjustment system, replace the solenoid valve with the three position four-way valve with high reliability, and use the system of "one pump with two cylinders". In this way, when one system of the shearer fails, the other height adjustment system will work, greatly improving the reliability of the system.

 

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