On-site rapid repair methods for construction machinery

1. "Planting silk" repair method

Screws are inserted into the machine body or component body to form a thread plug for sealing purposes. If a 6135 diesel engine cylinder block has a crack with a length of approximately 30mm. First, drill a crack prevention hole at each end of the crack pattern. Then, drill and tap the screw patterns in the order of 1, 3, 5, and 7 and screw in the copper screws. Drill the screw holes in 2, 4, 6, and 8 again and screw in the copper screws in the same way. When drilling, ensure that two adjacent screws have a 1/3 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 8mm. For instance, a ZL50 loader had a small hole in its oil tank that leaked oil. The hole diameter was approximately 4mm. A 5mm diameter steel punch was used to enlarge the hole, and the oil tank wall was thickened by edge rolling. Then, M6 screw holes were drilled and screws were screwed in to block and seal the hole.

2. "Displacement" repair method

Restore the original function by swapping the positions of components or changing the installation direction. For example, the main hydraulic pump of a ZL40 loader was damaged. After disassembly and inspection, it was found that the bronze wear-resistant layers on the front and rear side plates and the tooth surfaces of the driven gears 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 all single-sided wear, and the structural dimensions of the front and rear side plates and the main driven gear are exactly the same, the front and rear side plates are installed by swapping positions, and the driven gear is installed by flipping 1800 degrees, so that the friction direction of the bronze wear-resistant layer of the front and rear side plates is opposite to the original friction direction. The unworn tooth surface of the driven gear becomes the working surface, thus restoring the normal operation of the loader. For instance, since the working pump of the W4-60C excavator and the steering pump of the ZL50 loader are both CBG2 type gear pumps, they have the same installation dimensions but rotate in opposite directions. The GBG system gear pump features the ability to change the rotation direction by rotating the pump body and the front and rear side plates by 1800 degrees and reassembling them. After reassembly, they can be used interchangeably. For instance, when the gear ring of the engine flywheel is worn on one side and affects the normal start of the engine, the gear ring can be installed and used by flipping it over.

3. "Alternative" repair method

This is a repair method that uses local materials and makes full use of the materials around us to replace the damaged parts of construction machinery. It is mainly used as a temporary substitute for gaskets, oil seals, oil pipes, heat dissipation devices and wires, etc. For instance, a W4-60C excavator suffered from severe oil leakage due to a damaged hydraulic oil radiator. Therefore, the combined cooling method of forced and natural hydraulic oil was changed to a single natural cooling method. This way, the heat dissipation requirements of the system could be met and the operation of the excavator could be resumed. 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, which enabled it to resume operation quickly. The specific approach is as follows: First, cut the common used V-belt, with its length being the same as the circumference of the piston oil seal. Use the grinding method to shape its top, making the top width greater than the width of the piston oil seal ring groove. Then, cut the joint into 450 pieces to increase the contact area and reduce leakage. After assembly, the loader worked continuously for over 40 shifts and completed the construction task on schedule. In regular on-site repairs at construction sites, the following methods can also be adopted: Replace the return oil hose of the fuel system with ordinary plastic pipes; Use plastic gaskets made from Coca-Cola beverage bottles to replace the low-pressure oil circuit sealing gaskets. Replace the cylinder distribution wire in the ignition system of gasoline engines with cables. Use cigarette shreds mixed with 502 glue to seal the leak. Use rubber rings as return spring springs, etc.

4. "Short circuit" repair method

Short-circuit the oil pipes, air pipes or circuits in the hydraulic system, pneumatic system, fuel supply system and electrical equipment of the machinery, bypassing the faulty parts and directly connecting the pipelines or circuits. For example, in a ZL50 loader, the driver failed to drain the cooling water at night, causing the oil radiator to freeze and crack. It was decided to remove the oil radiator, but it also froze and cracked. Remove the oil radiator, connect the oil pipe to the oil passage of the engine body, and resume use. The relief valve of the steering system of a TL180 fast bulldozer malfunctioned. The "circuit breaker method" was adopted to restore its operation. The oil hole of the pilot valve core of the relief valve should be blocked or the oil inlet hole of the relief valve should be directly closed. It is also required that the driver must keep the engine throttle at a medium position during operation and must not work under a large throttle condition. During the operation of a W4-60C excavator, Pump A was damaged and the hydraulic system was paralyzed. A three-way joint was used to connect the oil discharge pipes of pump A and pump B, enabling Pump B to supply oil to the hydraulic system independently and restore the operation of the hydraulic system in a timely manner. 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 the system has lost its function of oil quantity regulation and distribution, it can still temporarily carry out loading operations. It should be noted that the short-circuiting and discarding method is merely an emergency repair approach.

5. "Bone setting" repair method

The damaged parts can be quickly repaired by methods such as binding, welding, clamping and bonding. For example, a W4-60C excavator experienced an interlaced fracture at the outer shoulder of the bearing housing of the rear axle wheel side reducer, and the annular tear width of the outer spline at the wheel center support part was 15mm. The replacement cost was nearly ten thousand yuan. Therefore, the "bone-setting method" was adopted to repair the fractured part. That is, the ring-shaped torn part of the fractured part was cut off (its axial length was shortened by 45.5mm), and then 45 # high-quality carbon structural steel was selected as the bone-setting material. Wood core positioning was used, and high-strength E5016(J506) welding rods were selected. Double-sided V-shaped bevels were applied. The repair task was completed in just 1 hour through multi-layer welding of DC reverse connection sections. A hydraulic oil pipe of a ZL40 loader broke. The pipe was sawn open from the break, and a steel pipe bone was used to cut "barbs" at both ends of the steel pipe, which were inserted into the hydraulic oil pipe to a depth of about 100mm. Then, 8# steel wire was used to bind it. Finally, the ends of the steel wires were twisted together to prevent the steel pipe from falling out of the oil pipe due to excessive oil pressure. The application of this method quickly restored the operational performance of the machinery.