Patent ID: 6168133
Filing Date: 2001-01-02
Classification: F02M

Abstract:
A valve for controlling liquids, comprising a piezoelectric actuator (32), a valve member (22) which is actuatable in an opening direction via a piston (25) by said piezoelectric actuator (32) counter to a force of a spring (24), said piston (25) includes a first face end (29) which closes off a hydraulic coupling chamber (30), said hydraulic coupling chamber (30) is defined on a second side by a second face end of an actuator piston (31) which has a larger diameter than a diameter of the piston (25) and is a part of said piezoelectric actuator (32), a working stroke of said piston (31) increases a pressure in the coupling chamber (30), the piston (25) is adjusted by said working stroke and the pressure in said coupling chamber (30) counter to the force of the compression spring (24), a low pressure chamber (33) is formed on an end of said piston (31) remote from the coupling chamber (30) and a low pressure chamber (18) is formed opposite a second face end of said piston (25) remote from said first end face (29), via the pressure chamber (18) a piston (15) actuates the valve member (22), respective low-pressure chambers (18 and 33) are provided in which oil leakage pressure prevails, a gap (36) is located between the outer circumference of the piston (25) and a guide bore (28) and a gap (35) is located between an outer circumference of the actuator piston (31) and a guiding bore (65) by which oil leakage is directed to low pressure chambers (18 and 33), said guiding bores (28 and 65) along the pistons (25) and (31) are dimensioned such that whenever there is no pressure increase in said coupling chamber (30), the coupling chamber (30) is refilled from the low-pressure chambers (18) and (33) via said gaps (28 and 65) to compensate for leakage losses via said gaps into the low-pressure chambers that occur during high pressure periods, and the periods that are between these occurrences of pressure increases are shorter than the periods during which the pressure increases occur.