Reasons for the failure of coal mine hoist coupling

　　With the development of coal mine production, the number of coupling replacements has gradually increased, so the accuracy of the journals has gradually decreased, causing the coupling of the coupling to fail and affecting the operation of the hoist.The connection between the coupling and the shaft is based on the interference between the shaft and the hole; the other is the interference between the key and the keyway.
　　(1) When the interference between the shaft and the hole is appropriate, the torque of the shaft can be transmitted separately; if the interference between the shaft and the hole is too small, the torque of the shaft is transmitted together with the key; most of the shaft and the hole are too small, and the interference is too small. As time goes by, the shaft and hole fit interference will lose the role of transmitting torsion, and the key will bear repeated alternating torque, the key will be slightly deformed due to extrusion, and the hole and journal of the coupling will also produce a small amount of circumferential Move, so that the two kinds of cooperation lose their due connection effect.
　　(2) Because of the interference between the coupling and the shaft, the hot-fitting and hot-suit processes are often used.When the shaft journal is inspected after the coupling is removed, there are: The shaft journal surface has different degrees of scratches and burns, which reduces the roughness; within the length of the journal, there are unplanned changes in the geometric shape of the shaft, which makes the shaft The cylindricity is out of tolerance; the keyway has different depths of indentation and burns, which makes the parallelism of the groove out of tolerance.