Justification of the choice of means of controlling the parameters of the crankshaft after processing for the repair size

Russian State Agrarian University – Moscow Timiryazev Agricultural Academy, Moscow, Russia

^* Corresponding author: temasova@rgau-msha.ru

Abstract

An assessment of the quality of the control of the parameters of the crankshaft after processing for the repair size was carried out. The company's metrological support system must guarantee the accuracy and quality of the crankshaft repair, eliminating the possibility of defects during subsequent assembly. When repairing engines, defects in the crankshafts are detected, after which they are replaced with new ones or processed according to the 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 to measure the diameters of the main and connecting rod necks of the crankshaft of the Zavolzhsky Engine Plant, as well as their ovality, it is necessary to replace the micrometer 50-75 (0.01) used at the enterprise, the maximum measurement error of which is twice as large as permissible, with a lever bracket 50-75 (0.002) 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, dial indicator 0-10 (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 calipers 0-125 (0.05) leads to an excess of the permissible measurement error by 3 times, but there are no other more accurate universal measuring instruments to control this parameter, since the control is carried out by special sponges for measuring holes, which are available only for calipers. It is recommended to design a gauge to measure the length of the third root neck.