Precision joint technology status simple inspection method

In the normal maintenance and maintenance of the machine, due to the lack of special inspection instruments and equipment, the quality of the plunger, the oil valve and the fuel injector can only be identified by observation, touch, auscultation and sensation. continue to use. Are introduced as follows:? 1. Plunger joint inspection? 1.1 Empirical method identification? (1) According to the situation of the sliding joint with the plunger to judge whether it can be used. Tilt the cleaned plunger assembly 45 and pull out 1/3 of the full length of the plunger. No matter if it is turned to any position, the plunger can fall slowly under its own weight. However, it must not fall too fast or get stuck, otherwise it should be replaced or repaired. (2) According to the plunger wear traces to determine whether it can be used? The wear of the plunger is mainly concentrated in the head, the wear marks are gray, no light. Tests have shown that a 8.5mm diameter plunger cannot be used when the head wear marks reach a width of 4 to 5mm and a length of 9 to 10mm, or when the fingernails are used to scrape. In addition, when the edges and corners are blunt, there are peeling or rust, and the plunger sleeve cracks or deep marks in the inner hole can not continue to use. (3) Can it be used according to the sealability of the plunger assembly? a. After the plunger assembly is cleaned with clean diesel oil, pull the plunger out of the plunger sleeve for about 1/2 of the full length. Block the axial surface of the top of the plunger sleeve and the oil inlet hole (positioning hole, a small amount of oil). Drip the diesel oil into the inlet hole and align the plunger chute into the back hole and slowly push it forward. In the process of advancing, if there are air bubbles coming out of the hole, it means that the plunger part is worn out and cannot be used; if there is no air bubble in the hole, only diesel will be exposed when the plunger chute is quickly exposed in the hole. Rapid spilling from the inside of the hole indicates that it can still be used. b. Place the plunger in the medium or maximum refueling position and push it to the top position. Block the axial bore of the plunger sleeve by hand. Then pull the plunger to the top of the plunger without exposing the plunger return hole. A vacuum suction is felt, and the plunger can quickly return to its original position after releasing it, indicating that it can continue to be used. c. Directly judge on the diesel engine according to the tightness. Remove the high pressure tubing connected to the fuel injection pump, suffocate the fuel pump high pressure tubing connector with a blanking nut, and turn the flywheel until it reaches the fuel supply position. Effortlessly still able to pull, indicating that the plunger has worn, can not be used, if the pull can not move or pull it hard, indicating that the plunger seal is good, can continue to use. 1.2 Identify directly on the locomotive? Install a new fuel injector or working injector on the fuel injection pump to be checked, adjust the fuel injection pressure to 1.96104kPa (200kg/cm2), swing the crankshaft to make the spray The oil pump supplies oil. If the fuel injection pump can make the fuel injector spray properly, the plunger coupler can continue to be used. Otherwise, replace the new one. 2 Outlet valve couple inspection? 2.1 Identification by experience? (1) Visually observable? a. When the sealing ring of the oil seal cone is depressed and the contact width is more than 1mm, it should not be used continuously. b. When the surface of the decompression belt has longitudinal wear grooves, and the original roughness cannot be seen, it should be repaired or replaced. c. Should be replaced when there is rust, crack and metal peeling on the mating surface of the oil outlet valve and valve seat hole. (2) Check on the engine? Remove the high-pressure fuel pipe from the fuel injection pump, depressurize and turn the crankshaft, and when the flywheel turns to compression top dead center, if there is still diesel outflow at the high-pressure fuel pipe joint of the fuel injection pump, the oil will flow out. The valve is worn out and can no longer be used, otherwise it can continue to be used. (3) Pull out the oil valve from the valve seat hole (not all), block the lower hole of the oil valve seat with the thumb, and then gently press the oil valve, if it is not pressurized, if it is out of oil If the valve can move upwards, the seal can be considered good. (4) Slightly loosen the joint nut of the high pressure oil pipe on the upper part of the oil valve seat, and depressurize the crankshaft. If the diesel is injected outwards, it proves that the technical state of the oil valve coupling is normal. If only the foam diesel is emitted, it will be shown. The oil valve is not sealed. 3 Injector Needle Valve Inspection 3.1 Auscultation method When the fuel injector is working normally, the sound is uniform and continuous, “哒, 哒” sound. When the injection pressure is too low, it will be uniform. Continuous "sound and bang" sounds accompanied by black smoke. When the needle valve issued a card, the sound was intermittent and there was no certain rhythm. When the nozzles drip, two sounds that are close to each other will appear and the exhaust will be released. 3.2 Do not dismantle and inspect? (1) Remove the injector from the cylinder and reconnect the high pressure tubing to the outside and place the throttle at the throttle position. Single-cylinder diesel engine decompression swing crankshaft, multi-cylinder engine oil pump pump oil, such as fuel injection crisp, good atomization, no drip phenomenon, indicating that the injector is in good technical condition, otherwise it should replace the oil head. (2) The crankshaft is decompressed and turned to the crankshaft, and the diesel fuel is ejected into a line. This indicates that the oil leakage at the end face of the nozzle is serious or there is a phenomenon of oil dripping, and new parts must be replaced. (3) Sensing method When the engine is running, touch the cylinder by hand. If no pulsation is detected, it indicates that the cylinder is faulty. If the plunger pair and the outlet valve are in good condition, the cylinder is injected with oil. When the nozzle is stuck, the couple must be replaced.

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