Research And Application Of Clamp-coordinated Rest On Crankshaft Grinding

The crankshaft is a key component of the automotive and other internal combustion engine which has high requirements to material,size,shape and tolerance.The processing quality and processing efficiency directly affect the quality of automobile products and the development of the automobile industry.Currently the rest has been used as the auxiliary support to enhance the concentration of crankshaft processing and to improve stiffness and machining precision of parts.The clamp-coordinated rest designed by foreign manufacturers is used in the lath and grinding machine widely.But the core technology is not open and the research of the rest is not mature at home.To design a clamp-coordinated rest and set up a model to confirm the concrete structure.According to the actual requirement,the grinding force of the certain type of crankshaft was calculated.When pre-grinding M1 and M4,grinding force is maximum which is 641.68N.Analytic method and finite element analysis method are used to analyze and calculate the crankshaft deflection.The grinding force is applied on the 180 degrees of crankshaft,the maximum deformation is 3.854E-2mm.The finite element analysis is used to confirm that the best clamp position is M2 and minimum clamping force is 600N.The best angle of 103 degrees,which we can confirm the running surface angle is 13 degrees and inclined angle of the middle plate is 51.5 degrees.To calculate and confirm the hydraulic cylinder size of rest and determine that the diameter of the piston of the hydraulic cylinder should reach 4.04 cm.The formula which the claw width should be satisfied has been determined.The finite element analysis method is used to confirm the shell size and middle plate size of rest.The length is 285mm and the width of support on both sides is 25mm.The groove depth on both sides of the center plate and clamping thickness are 10mm.At last,the structure and the specific size of rest are confirmed.To confirm the rest repeatability accuracy is in the range of 0.002mm by off-line testing.The rest designed by us is applied to a JUNKER grinder in crankshaft machining line.The accuracy of upper line is 0.001mm,and the accuracy of side line is 0.002mm.The repeatability accuracy is in the range of 0.002mm yet.The rest designed by abroad company is applied to a JUNKER grinder.The accuracy of upper line is 0.002mm,and the accuracy of side line is 0.003mm.The repeatability accuracy is in the range of 0.001 mm yet.The requirement of crankshaft grinding process is that the repeatability accuracy is in the range of 0.005 mm,which means the rest can meet the production requirements of high precision.