Experimental investigation to enhance the automotive gearbox synchronizer life and gear shift quality

Abstract

Manual Transmission is the most preferred transmission in the newlineemerging markets due to the low ownership cost and the low maintenance newlinecost with a higher transmission efficiency. So, it is very essential to newlinecontinuously improve the gearbox endurance life and gear shift quality to newlinemeet customer expectations. In a manual transmission, the drivers interact newlinewith the gearbox through the synchronizer for each gear shift operation. The newlinesynchronizer synchronizes the upstream rotational speed with the downstream newlinerotational speed for gear changing. newlineThe designed endurance life of the synchronizer ring is 200,000 km. In newlinethe vehicle validation, the synchronizer ring carbon linings worn-out quickly newlinein less than 20,000 km. Due to wear, the synchronizer wear gap of 1.5 mm newlinereduces to zero. This hampers synchronization and creates an early gear crash newlineduring gear change in the vehicle. The research work is divided into 3 phases. newlineIn the entire work, the researcher aims to improve the synchronizer endurance newlinealong with improved gear shiftability to provide overall customer satisfaction. newlinePhase1: To understand the route cause for the synchronizer ring wear, newlinethe synchronizer ring endurance life was checked in the synchronizer test rig, newlinetransmission test bench, and in the vehicle for the abuse gear shift load newlineconditions and no abnormal wear observed. The driver driving pattern in the newlinehighway durability test shows that the driver uses the 4th, 5th, and 6th gear for newlinethe 80% of duty. In the operating speed of 1000 to 1700 rpm, newline