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Check The Wear Of The Crankshaft

2021-11-25


(1) Inspection of the surface wear of the journal. The dimensions of each part of the journal are measured with an outside micrometer. Two measurement positions should be selected for each journal, and two measurement directions should be vertical and parallel to the crankshaft arm. Then calculate the taper, ovality and wear. If the taper or ellipse exceeds the limit, repair is required.

(2) Inspection of crankshaft bending (using the top of a grinder or lathe, if the conditions are not enough, a platform and a V-shaped frame iron can also be used). Use the top of a grinder or lathe to align the center holes at both ends of the crankshaft (use a chuck to clamp both ends of the crankshaft) to set up the crankshaft. Check the correctness of the center hole. Use a micrometer to check the neck swing difference between the flywheel adapter and the timing gear (not more than 0.5mm at the flywheel adapter, and not greater than 0.6mm at the timing gear journal). When the above limit is exceeded, the center hole must be trimmed. Check the swing difference between the intermediate journals, place the micrometer on the surface of the grinding machine, make the needle touch the central main journal, and push the crankshaft for a full circle. The maximum number of pointer swings minus half of the minimum is the curvature ( Note that if there is an ellipse on the journal, it needs to be subtracted), but it cannot exceed the specified standard.

(3) Inspection of mechanical damage of each joint part. For the wear of the bearing hole at the rear end of the shaft, use the inner diameter indicator to measure whether the clearance between the inner diameter and the outer diameter of the bearing exceeds the limit. If the shaft shoulder is worn, check the axial clearance and whether the width of the shaft shoulder exceeds the limit. For keyway wear, the inner diameter indicator can be used to check the width of the most severely worn keyway bottom. Flywheel fixing screw holes are worn out, check the fit with new screws. The abrasion of the oil-resisting thread can be measured with a special template or a depth-sounding vernier caliper and the depth shall not be lower than the specified standard. Visually inspect the journal surface for scratches and cracks.

(4) Inspection of crankshaft cracks. Cracks on the surface of the journal, after the journal is wiped clean and carefully observed with a magnifying glass, the cracks will be clearly found.