DESIGN, DEVELOPMENT AND LONG-TERM OPERATIONAL VALIDATION OF A COMPACT DUAL-SPEED GEAR REDUCER FOR AGRICULTURAL HARVESTING EQUIPMENT

ABSTRACT: Agricultural harvesting machinery frequently requires adaptation to specific operational requirements imposed by crop characteristics and harvesting technologies. This paper presents the design, manufacture and long-term operational validation of a compact dual-speed mechanical reducer developed for an agricultural harvesting machine. The purpose of the project was to reduce the rotational speed of an existing transmission system from 400 rpm to approximately 200 rpm without modifying the external dimensions of the original pulley assembly. The proposed solution incorporates a compound spur gear train inside a pulley acting simultaneously as housing and transmission hub. Special attention was given to dimensional constraints, transmission ratio optimization, reliability and ease of maintenance. The developed reducer provides two operating modes, namely reduced-speed operation and direct-drive operation, allowing increased versatility under different harvesting conditions. Following manufacture and installation, the reducer was subjected to continuous field operation on a harvesting machine for more than ten years. Operational observations indicate stable functioning, low maintenance requirements and the absence of significant wear or structural failures. The obtained results demonstrate that compact gear-based transmission systems remain efficient and economical solutions for agricultural machinery modernization.