Definition of Slippage Parameters of Friction Clutches in Gearboxes with Fixed Shaft Axles
The paper is about a calculation method for slipping parameters of friction clutches (of the slipping work and time) in tractor gearboxes at various gear overlaps and at bench tests of full-sized prototypes.
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Abstract The paper is about a calculation method for slipping parameters of friction clutches (of the slipping work and time) in tractor gearboxes at various gear overlaps and at bench tests of full-sized prototypes. Keywords Gearbox
Slippage Clutch Friction Fixed shaft axles
Modern wheeled and track vehicles broadly use the gearboxes, where gearing is made both with and without interruption of power flow from the engine by means of friction clutches (FCs) with hydraulic constriction and different gear overlapping. However, until today, the gear shifting process executed inside the gearbox by means of FCs has not been completely studied. As an example, let us consider the gear shifting process in a tractor gearbox. The gear shifting under load can be made both with and without a short-term interruption of power flow from the engine. The continuous (non-break) gearing ensured by simultaneous operation of two gears within a short period of time tp (gear overlap time) has some peculiarities. The process of continuous gear shifting depends on the parameters of the FCs, which ensure shifting, the overlap duration, specifications of the tractor unit (or machine-tractor unit–MTU) and its operation conditions.
F2012-C02-001 M. Dmitriev (&) V. Sharipov Moscow State University of Mechanical Engineering (MAMI), Russian Federation, Moscow, Russia e-mail: [email protected]
SAE-China and FISITA (eds.), Proceedings of the FISITA 2012 World Automotive Congress, Lecture Notes in Electrical Engineering 193, DOI: 10.1007/978-3-642-33744-4_7, Springer-Verlag Berlin Heidelberg 2013
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M. Dmitriev and V. Sharipov
Fig. 1 Double-mass vehicle dynamic system with elementary gearbox. 1—driving shaft, 2— driven shaft; FK1 and FK —FCs of the K 1 and K gears respectively; MD —torque on the engine shaft, brought to the shaft of the engaged FC, xD —angular velocity of the engine shaft, brought to the shaft of the engaged FC; JD —the inertia moment of moving parts of the engine and parts connected thereto, brought to the shaft of the engaged FC; MC —the resistance moment to motion, of the tractor unit brought to the driven shaft of the gearbox, JN —the inertia moment of the tractor unit brought to the driven shaft of the gearbox; xN —the angular velocity of the driven shaft of the gearbox; and uk1 and uk —the transmission ratios of the gearbox at the K 1 and K gears respectively
Fig. 2 Acceleration diagram of the tractor unit at gear shifting without interruption of the power flow from the engine. a with a flat section (tb [ tm ), b shape of ‘‘triangle’’ (tb tm )
Let us consider the gear shifting process with overlap at shifting from lower to higher gear on the example of an elementary gearbox with two parallel shafts (Fig. 1). The basic parameters defining the gear shifting process are the work L and the time tb of FC slippage FK when shifting to higher gear. To define these parameters, let us make use of a theoretical diagram for acceleration of the tractor unit (Fig. 2), which assumes that the friction torque
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