PROPORTIONAL ELECTRO-HYDRAULIC MECHANISM FOR CONTROL OF FRICTION CLUTCHES OF HYDROMECHANICAL TRANSMISSION OF A MOBILE MACHINE Russian patent published in 2019 - IPC F15B13/44 F16H61/06 

FIELD: machine building.

SUBSTANCE: control mechanism can be used in systems with electromagnetic proportional control of hydromechanical transmissions. Mechanism comprises a pilot stage with a ball valve mechanism and a second stage with a differential slide valve. On the outer surfaces of the working spools of the spool, throttling recesses of a certain size are made, which form a positive overlapping of throttling feed slots and draining of the working fluid of the controlled friction with a certain ratio of dimensions. In the channel of working fluid supply into the pressure control chamber of the ball valve mechanism there are two in-series throttles, which allow to reduce losses of liquid to the drain in the switched off state of the control mechanism. Throttle is installed between pressure control chamber and slide valve control chamber, which together with feedback throttle made in slide valve allows reducing amplitude of oscillations of slide valve during pressure control. Throttling section pass-through area on working spool valve allows progressive and smooth change at slide valve movement. Two identical throttling recesses are made in each of two working spools of spool of identical diameter. Pilot and second stages are arranged coaxially in separate housings combined into common unit.

EFFECT: invention provides smooth pressure control, stability of friction control characteristics, increases operating properties of friction control mechanism, stabilizes process of friction control, reducing mutual effect of ball and spool vibrations during pressure control, reduces hysteresis of control characteristics and loss of working fluid to drainage.

3 cl, 10 dwg