Year of Publication

2023

College

Agriculture, Food and Environment

Department/School/Program

Biosystems and Agricultural Engineering

Degree Name

Bachelors of Science

Faculty Advisor

Alicia Modenbach

Abstract

The University of Kentucky (UK) Wildcat Pulling Team competes in the annual ASABE International Quarter Scale Tractor Student Design Competition. In 2022 the team placed 3rd overall in the competition, missing 1st place by 23 points. The loss in points was due to the clutch subassembly having issues related to maneuverability, manufacturability, and serviceability. The goal of this project was to redesign the 2022 tractor’s drivetrain for the new 2023 competition tractor. Background research was conducted on three types of clutches: manual, electric, and centrifugal. The electric clutch and centrifugal clutch with manual override were tested to determine their viability for the application. The electric clutch does not allow for easy maneuverability due to its high starting acceleration by instantaneous connection of the magnets. Changing the duty cycle and ramp duration could decrease the starting acceleration; however, the rider still experienced significant starting whiplash, and there were concerns with durability. The centrifugal clutch automatically engages at 2700 rpm threshold and is inactive below that threshold. A hydraulic throwout bearing was used to manually override the engagement threshold on the centrifugal clutch to engage at lower speeds. This configuration showed positive results, as no significant power loss was observed, and the configuration worked as anticipated without any wear on any of the parts. Test results indicated that the centrifugal clutch configuration was the better choice for this application. The final design is a belt-driven system with two cantilevered shafts connected on the backplate with a removable cover, improving access for serviceability.

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