Rigid couplings currently mainly adopt the coupling method of coupling sleeve and tapered pin, and most of the feed motor shafts are equipped with flat keys.After using this connection for a period of time, the tapered pin begins to loosen, and the gap between the side of the keyway gradually increases, and sometimes even causes the tapered pin to fall off, resulting in unstable parts processing dimensions.There are two solutions:

　　(1) A special small-head taper pin with thread is used, and the taper pin is locked with a nut and an elastic washer to prevent the taper pin from loosening due to rapid conversion.This method can well solve the problem of the looseness of the tapered pin, and at the same time reduce the torque borne by the flat key.Of course, this method has a nut on the small head of the tapered pin to ensure that the coupling has a certain rotation space.

　　(2) Two elastic pins, one large and one small, are used to replace the conical pin connection. Although this method does not have the high accuracy of the conical pin connection method, it can solve the problem of the looseness of the conical pin. The elastic pin has certain elasticity and can The torque that the flat key bears is broken down, and the structure is compact, and the assembly is also very convenient.After being used in maintenance, the effect is very good.But pay attention to when assembling, the big and small elastic pins are required to be assembled at 180°, otherwise it will affect the accuracy of parts processing.

　　Flexible coupling is a coupling widely used in CNC machine tools. It can compensate for the "interference" phenomenon caused by coaxiality and perpendicularity errors.Under the condition that the structure allows, most of the servo feed systems of CNC machine tools adopt the flexible coupling structure.However, it is difficult to know whether the taper sleeve is locked when the flexible coupling is assembled. If the friction force is insufficient after the taper sleeve is expanded, the screw shaft head and the motor shaft head will have relative slip and torsion, causing the CNC machine tool to operate. , The size of the processed part presents a regular and gradual change (from small to large or large to small), and the value of each change is basically constant.If the rapid feed rate of the machine tool is adjusted, this amount of change will also change. At this time, the CNC system does not alarm, because the motor rotation is normal, and the encoder feedback is also normal.