New Roto-Translating Valve Functional and Safety Feature Analysis

The paper deals with a new concept of hydraulic spool valve that allow the design of new safer hydraulic circuit architectures, ensuring higher functional safety performance. The new patented spool valve presents a secondary rotary type actuator connected to a sleeve, interposed between the spool and the valve body, thus composing a roto-translating valve. The sleeve presents holes that can be moved and positioned partially or totally overlapped to the valve ports, thus allowing a secondary independent metering. The valve port area is the result of two actuators position, both controlled by a microcontroller based unit. Due to the valve structure, the metering control precision and valve speed are virtually quadratic in respect to the traditional valve spool position electronic control, due to the concurrency of two electronically controlled actuators. The sleeve holes and the spool notches can be designed to realize various control functions and, in terms of safety, to offer fail operational characteristics.