Hydrostatic drive • Bondgraph modeling • High speed low torque (HSLT) • Low speed high torque (LSHT) • Hydro-motor • Loss coefficients • Slip • Torque loss • Efficiency • Rock strength List of symbols D p Volume displacement rate of the pump (m 3 /rad) D pmax Maximum volume displacement rate of the pump (m 3 /rad) D mh,ml Volume displacement rate of the HSLT or LSHT hydro-motor (m 3 /rad) J ld Generalized load inertia of the driving shaft (Kg m 2) J ldh,ldl Load inertia of the HSLT or LSHT driving shaft (kg m 2) K cp Bulk stiffness of the fluid at pump plenum (N/m 5) K cmh,cml Bulk stiffness of the fluid at HSLT or LSHT hydro-motor plenum (N/m 5) M ih,il Angular momentum due to load inertia of the HSLT or LSHT drive (kg m 2 /s 2) M ih,il Torque due to load inertia of the HSLT or LSHT driving shaft (Nm) N mah,mal Actual rotational speed of the HSLT or LSHT hydrostatic drive (rad/s) N mi Ideal rotational speed of the hydrostatic drive (rad/s) N mih,mil Ideal rotational speed of the HSLT or LSHT hydrostatic drive (rad/s) N mp Predicted rotational speed of the hydrostatic drive (rad/s) N p Speed of the pump (rad/s) P lmh,lml Load pressure of the HSLT or LSHT hydromotor (N/m 2
In this article, performance of a closed-circuit hydrostatic drive in primary and secondary mode of operations has been studied through theory and experiment. This drive consists of a variable displacement pump that supplies pressurized fluid to a variable displacement hydro-motor of bent axis design. Bond graph simulation method is adopted for system modeling. In the model, the losses of the drive are accounted by suitable resistive elements, and their characteristics are identified through experiments. The predicted drive’s performances are studied with respect to the overall efficiency, torque loss (%), and slip at different torque levels which are also validated experimentally. The investigation made in the article identifies the efficient zone of operation of the drive which will be useful to the practicing engineers to select such a drive used in heavy constructional equipment. From the steady-state performance of the pump and the motor, their critical control parameters are identified. The studies may be useful for the design of the suitable control strategy to obtain the optimum performance of the drives.
This paper highlights the steady-state performance of open-circuit hydrostatic drives for the rotary head of drill machine through modeling and experiment. In this respect, two alternative drive systems are considered. A drive system that consists of a variable displacement pump and two high-speed low-torque hydro-motors with a gear reducer unit and the other one consists of an identical pump and a low-speed high-torque hydro-motor. The steady-state model of the proposed drive arrangements is made by bondgraph simulation technique, where the relationship of the various losses of the components are obtained as a function of operating parameters and are identified experimentally. Using them, the slip and torque loss along with the overall efficiency of the drives are characterized. The performances of the hydrostatic drives are compared for the usual operating speed range of the drill machine used in mining operation. The studies made also identify the operating range of the proposed hydrostatic drives with reasonable efficiency. Keywords Hydrostatic drive, bondgraph modeling, continuously variable transmission, pump, high-speed low-torque hydro-motor, low-speed high-torque hydro-motor, loss coefficients Date
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.