Ensuring the Quality of Control of the Crankshaft of the ZMZ Engine at Repair Enterprises

Abstract

An assessment of the quality of control of the parameters of the crankshaft of the ZMZ engine at the repair company was carried out. The metrological support system of the enterprise must guarantee the accuracy and quality of the repair of the crankshaft of the ZMZ engine, excluding the possibility of marriage during subsequent assembly. When the engines are repaired, the crankshafts are defective, after which they are replaced with new ones or processed for repair size. After processing the crankshaft for the repair size, it is necessary to carry out control according to six parameters. It was revealed that in order to measure the diameters of the main and connecting rod necks of the crankshaft, as well as their ovality, it is necessary to replace the micrometer 75-0.01 used at the enterprise, the maximum measurement error of which is twice as large as the permissible one, with a lever bracket 75- 0.002, in order to reduce the measurement error and improve the quality of control. To control the greatest beating of the second, third and fourth root necks relative to the first and fifth root necks, the hour-type indicator used at enterprises fully satisfies the specified conditions, the maximum error does not exceed the permissible one. To control the axial clearance of the already assembled crankshaft along the thrust bearing, 10-0.01 is also used, which provides the specified measurement accuracy with a three-fold margin. When measuring the length of the third root neck, the use of a caliper 125-0.05 leads to an excess of the permissible measurement error by 3 times, but there are no other more accurate universal measuring instruments for monitoring this parameter, because control is carried out by special sponges for measuring holes that are available only for calipers. It is recommended to design a gauge for the purpose of measuring the length of the third root neck.