This thesis proposes a new type of hydraulic valve: an adjustable-ratio flow divider. This valve attempts to split one input flow into two output flows in a predetermined ratio, independent of load pressure or total flow. The valve uses a two dimensional structure to form a two-stage valve with only one moving part; the pilot stage uses the spool s rotary position, and the main stage uses its linear position. This arrangement allows for a cheaper, simpler valve with smaller volumes (translating into faster response). The ratio of outlet flows can be set on the fly by the angular position of the spool, driven by a stepper motor or other low-power input. In order to evaluate the initial feasibility of the concept, steady state and dynamic models were developed and the effects of the physical parameters were studied. Two non-linear non-derivative multiobjective optimization strategies were used to determine the optimum parameters for a prototype. Finally, the prototype s performance was experimentally examined and appears to work as expected.

This thesis proposes a new type of hydraulic valve: an adjustable-ratio flow divider. This valve attempts to split one input flow into two output flows in a predetermined ratio, independent of load pressure or total flow. The valve uses a two dimensional structure to form a two-stage valve with only one moving part; the pilot stage uses the spool s rotary position, and the main stage uses its linear position. This arrangement allows for a cheaper, simpler valve with smaller volumes (translating into faster response). The ratio of outlet flows can be set on the fly by the angular position of the spool, driven by a stepper motor or other low-power input. In order to evaluate the initial feasibility of the concept, steady state and dynamic models were developed and the effects of the physical parameters were studied. Two non-linear non-derivative multiobjective optimization strategies were used to determine the optimum parameters for a prototype. Finally, the prototype s performance was experimentally examined and appears to work as expected.

This thesis deals with design of hydrostatic drive for multipurpose loader and tool carrier DAPPER. At the beginning is research of different basic concepts and modern solutions to the problem, aided by a detailed description of competitive machine in the same performance category. Extensive comparison with other producers is included in the annexes to this thesis. Furthermore, a theoretical driving characteristic and its appropriateness is examined further on the basis of two model situations. The calculations of the individual components of the hydraulic circuit precedes drive kinematics analysis of articulated machine frame, on it final conception of hydrostatic drive is chosen. Firstly hydromotors and hydogenerator are chosen on the grounds of calculations then hydraulic hoses, filters and flow divider. Next chapters are aimed to calculations of hydraulic losses and thermal calculation of hydraulic circuit. Final part deals with introduction the final characteristics of drive. The practical parts of the work are assembly drawings with main power components and hydraulic schematic of drive.