Introduction to the causes of crankshaft wear
The crankshaft often wears out during use, which affects the normal operation of the engine. So what are the reasons for crankshaft wear? Let's take a look at the cause of crankshaft wear.
The elliptical wear of the journal is caused by the uneven distribution of the forces acting on the journal in the circumferential direction. When the engine is working, the combined force of the connecting rod journal always acts on the inner side of the connecting rod journal, and the direction is outward along the radius of the crankshaft, causing the inner side of the connecting rod journal to wear the most, forming an elliptical shape. The reason for the taper wear of the connecting rod journal is that the oil passage to the connecting rod journal is inclined. When the crankshaft rotates, the mechanical impurities in the lubricating oil are concentrated on the connecting rod journal under the action of the centrifugal force. On one side, the wear of the side journal is accelerated, and the wear of the connecting rod journal is tapered. In addition, the bending of the connecting rod, the center line of the cylinder and the center line of the crankshaft are not perpendicular, etc., which causes the journal to be unevenly biased in the axial direction and deflect the wear.
The wear on the surface of the crankshaft journal is uneven. The radial wear of the main journal and the connecting rod journal is mainly elliptical, and the maximum wear parts correspond to each other, that is, the maximum wear of each main journal is close to the journal side of the connecting rod. The maximum wear of the connecting rod journal is also near the side of the main journal. The crankshaft journal also has tapered wear in the axial direction.
The wear of the main journal is elliptical, mainly due to the centrifugal force of the connecting rod, the connecting rod journal and the crank arm, so that the relative wear on the side close to the connecting rod journal and the bearing is large.
In addition, scratches and burns may occur on the journal surface. The abrasion is mainly due to the fact that the oil is not clean, and the large hard mechanical impurities are caused by the scoring of the journal surface. The burn on the surface of the journal is caused by burning the tile. The burnt tile is mainly caused by insufficient lubrication, excessive oil, and oil blockage.
The above is the introduction of the cause of crankshaft wear. I hope that everyone can understand the cause of crankshaft wear and it will help everyone to repair the crankshaft.