To develop a technique to measure the diameter of crankshaft journal using three point contact.

Abstract

The purpose of this project is to design and manufacture the crankshaft inspection machine. This machine will be able to measure the diameter of crankshaft journal using three-point contact for both 3 cylinder and 4 cylinders. The measurement is done using three LVDT sensors with an accuracy of +_1 micron which are pointed towards the center of the crankshaft journal. The sensors are attached with the C type block mechanism that takes the readings over defined intervals. Two centers, Head stock and pneumatic tail stock are used to hold the crankshaft in place while inspection. Sensors are stationary and the crankshaft rotates by the means of stepper motor attached via belt. Three-point measurement is done by calculating the coordinates of all three points and then by using the least square approximation method, the radii is calculated by simultaneously solving the circle equations. The accuracy and precision is specified by the drawings provided by OEM. The design is optimized to take readings for the journals in such a way that radial alignments of probes become irrelevant. It is mainly due to innovative arrangement that allows point contact to the journal surface and has not been seen in precision measurement industry.