Design And Analysis Of Dual PTO For Medium And Heavy Multifunctional Trucks

Generally, trucks are equipped with only one engine to power the running of the truck, while power takeoff(PTO) is necessary for multi-functional special trucks(MST) to supply more power to drive the apparatus, such as PTOs installed on the flywheel of the engine, on the transmission and on the AWD trucks.Medium trucks and heavy trucks like vacuum cleaning trucks, asphalt distribution trucks, high-pressure sewer flushing trucks, dry-mixed mortar trucks and powder material trucks are in high demand with the increasing of engineering construction and the requirement of garbage gathering. Each of these trucks has two or more apparatuses to be driven, for which less than 50 kW power is needed.Multi-PTOs for transmissions have been very common abroad, such as PTOs for transmissions of various cars designed by Internet POP. And transmissions with multiPTOs are also common in China, like FAST transmission produced by FAST Gear Corporation, which has two countershafts and can take off the power ahead, from the bottom and from the left rear and right rear, by installing PTOS at different parts. Usage of multi-PTOs significantly enhance the convenience of MST.Different PTOs are fit for different transmissions and it's difficult to choose proper PTOs for trucks. Some trucks are equipped with deputy engines and others with transfer cases, which increases the cost as well as the difficulty of vehicle packaging.This paper develops a dual PTO to satisfy the market demand and dominate the market. The main content includes:The structure and packaging scheme of the dual PTO—constructing the Pro/E threedimensional model of dual PTO by market research and comparison of similar products and designing of the structure of PTO and its packaging scheme on transmission.PTO is located behind the accelerator and the output must be far away from the center line of the accelerator, which satisfies the requirement of special arrangement and makes it more convenient. PTO is designed to be two-shaft without a transitional shaft, in which case the input shaft power equals output shaft power, simplifying the structure and enhancing the efficiency. The speed ratio parameter of output 1 is determined according to the common PTO parameters, and the parameter of output 2 is set based on the existing PTOs of a certain company.Strength check of PTO—including the joint strength, shell strength and gear engagement strength; constructing the finite element model with MSC.Patran and conducting finite-element analysis of typical condition with MSC.Patran and Nastran to design a PTO satisfied for the market.Bench test for sample machine of the PTO—conducting life cycling test, static torsional strength test and shifting performance tests for joining under reasonable test specifications to optimize the design.This design is based on a transmission with double intermediate shaft master carton and planetary gear deputy carton and focuses on the multi-PTO matching of transmission of HW15.HW19 series to satisfy the market demand of multi-functional special truck.