On-site emergency repair methods for construction machinery

1? "Planting silk" repair method

That is, screws are inserted into the machine body or component body to form a plug for sealing. For instance, a 6135 engine block developed a crack (30 mm in length). First, drill a crack prevention hole at each end of the crack, and then press 1, 3, 5, 7... Drill and tap in sequence and screw in the copper screws, then in sequence 2, 4, 6, 8... Drill the screw hole and screw in the copper screw in the same way. When drilling, ensure that two adjacent screws have a one-third overlap. The depth of screwing in is preferably the same as the wall thickness at that location. Finally, gently tap the screw head with a hand hammer to seal it. The diameter of the screw is preferably 6 to 8 mm. Another ZL50 loader's oil tank has a small hole causing oil leakage, with the hole diameter being approximately 4 mm. Find a steel punch with a diameter of 5mm to expand the hole, increase the thickness of the fuel tank wall by rolling the edge, drill the M6 screw hole and screw in the screw to block and seal the hole.

2? "Displacement" repair method

That is, to replace the installation with its own components or change the installation position and direction to restore the original machine's function. For instance: ① The main hydraulic pump of a ZL40 loader was damaged. After disassembly, it was found that the bronze wear-resistant layers on the front and rear side plates and the working surfaces of the driven gear teeth were all worn to varying degrees. Based on the fact that the wear of the front and rear side plates and the tooth surfaces of the driven gear is single-sided wear, and the structure and related dimensions of the front and rear side plates and the driving and driven gears are exactly the same, the front and rear side plates are installed in opposite positions, and the driven gear is installed by flipping 180°. This can make the friction direction of the bronze wear-resistant layer of the front and rear side plates opposite to the original The unworn tooth surface of the passive gear became the working surface, restoring the normal operation of the loader. The working pump of the W4-60C excavator and the steering pump of the ZL50 loader are both CBG2 type gear pumps, with the same installation dimensions but opposite rotation directions. According to the feature of the CBG series gear pumps that the pump body and the front and rear side plates can be rotated 180° and then reassembled to change the rotation direction, they can be reassembled and used interchangeably. When the flywheel gear ring of the engine is affected in normal starting due to unilateral wear, it can also be installed upside down for reuse.

3? "Alternative" repair method

That is, to use local materials to replace the damaged parts of construction machinery. It is mainly used as a temporary substitute for gaskets, oil seals, oil pipes, radiators and wires, etc. For instance: ① There is a W4-60C excavator. Due to the damage of the hydraulic oil radiator, the oil leakage is severe. Therefore, it was decided to change the combined cooling method of forced and natural hydraulic oil to a single natural cooling method. This way, the heat dissipation requirements of the system can be met and the operation of the excavator can be resumed. ② The piston oil seal of a hydraulic cylinder of a ZL40 type loading boom was damaged. A V-belt was used to replace the piston oil seal, and it quickly resumed operation. The specific approach is as follows: First, cut a piece of ordinary used V-belt, with its length being the same as the outer circumference of the piston oil seal. Then, shape its top by grinding to make its top width 1? Wider than the ring groove of the piston oil seal. 0 to 1? It is 5 mm thick and its joint is cut at a 45° Angle to increase the contact area and reduce leakage. ③ During regular repairs at the construction site, the following methods can also be adopted: replace the return oil hose of the fuel system with ordinary plastic pipes, replace the low-pressure oil circuit sealing gasket with plastic gaskets made from Coca-Cola beverage bottles, replace the cylinder distribution wire of the gasoline engine ignition system with cables, use cigarette smoke mixed with 502 glue for leak sealing, and use rubber rings as return springs, etc.

4? "Short circuit" repair method

That is to short-circuit the oil pipes, air pipes or circuits in the hydraulic system, pneumatic system, fuel supply system and electrical equipment of construction machinery, bypassing the faulty parts and directly connecting the pipelines or circuits. For instance: ① There was a ZL50 loader whose oil radiator cracked due to the driver not draining the cooling water at night. At this point, we removed the oil radiator, directly connected the oil pipe to the oil passage of the engine body, short-circuited the water pipe of the oil radiator, and restored its performance. ② The relief valve of the steering system of a TL-180 fast bulldozer malfunctioned. The "circuit breaker method" was adopted to restore its operation, which involved blocking the oil hole of the pilot valve core of the relief valve or directly closing the oil inlet hole of the relief valve. It should be noted that when operating, the driver must keep the engine throttle at a medium position and must not work under a high throttle condition. ③ During the operation of a W4-60C excavator, Pump A suddenly broke down, causing the hydraulic system to collapse. We used a three-way joint to directly connect the oil discharge pipes of pump A and pump B, enabling Pump B to supply oil to the hydraulic system independently and promptly restoring the operation of the hydraulic system. ④ The spring of the valve stem of the flow distribution valve of a ZL50 type loader broke and could not be replaced immediately. It was decided to remove the valve stem to make the valve body a multi-path joint to connect the oil circuit. Although this depriving the system of the function of oil quantity regulation and distribution, it can temporarily carry out loading and unloading operations. It should be particularly noted that the short-circuit disposal method is only an emergency repair approach and should not be used for a long time.

5? "Bone setting" repair method

That is, to quickly repair damaged parts by methods such as binding, welding, clamping, and bonding. For example: ① There is a W4-60C excavator. At the outer shoulder of the axle housing of the rear axle wheel side reducer, there is an interlaced fracture, and the outer spline at the wheel center support part is torn in a ring (with a width of 15mm). If the replacement would cost nearly ten thousand yuan, it was decided to carry out welding repair on the broken part by the "bone setting method". Cut off the annular torn part of the fracture site (its axial length is shortened by 45?) Then, select high-quality carbon structural steel No. 45 as the bone-setting material. It was machined, with high-strength E5016 (J506) electrodes selected. Double-sided V-shaped bevels were used, and DC reverse connection was applied for multi-layer welding in sections. The repair task was completed in just one hour. ② A hydraulic oil pipe of a ZL40 loader burst. It was decided to saw through the burst and use steel pipe bones, that is, to process "barbs" at both ends of the steel pipe and insert them into the hydraulic oil pipe to a depth of about 100mm. Then, 8 # iron wire was used to bind it. Finally, the ends of the iron wire were twisted together to prevent the steel pipe from falling out of the oil pipe due to excessive oil pressure, quickly restoring the machine's working performance.