A pilot valve assembly (10) includes a cylindrical connector (12) having a first end portion (16) with external threading (18) for engaging a threaded control socket (106) of a hydraulic valve (100), and a second end (20) with an array of teeth (22) arrayed around its edge. A circumferential slot (24) around connector (12) is spaced from second end (20). The assembly also includes a pilot valve (26) with a mechanism for controlling a pressure within the hydraulic control valve actuator chamber. Pilot valve (26) is formed with a recess (28) having a complementary teeth (30) for engaging teeth (22) of connector (12) in a range of angular orientations. A clamping arrangement engages slot (24) and clamps pilot valve (26) to second end (20) of connector (12), thereby fixing an angular orientation of the pilot valve.

A hydraulic system may include an electrohydraulic control valve disposed in fluid communication between a source of pressured fluid and a hydraulic actuator. The hydraulic system may be controlled to correct for offset errors between a target actuator pressure and a current actuator pressure output from the control valve, without amplifying pressure oscillations in the fluid between the control valve and the hydraulic actuator.

An example valve includes: (i) a pilot seat member comprising a first channel and a second channel, a pilot seat, and a pilot sleeve portion comprising a pilot chamber and a cross-hole; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring, wherein the pilot check member is configured to be subjected to a fluid force of fluid in the second channel; and (iii) a solenoid actuator sleeve slidably accommodated about the pilot sleeve portion, wherein the solenoid actuator sleeve comprises a cross-hole and an annular groove, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to a second port of the valve, and the annular groove is configured to selectively fluidly couple the first channel to the second channel based on a position of the solenoid actuator sleeve.

An example valve includes: a pilot seat member comprising: a channel that is fluidly coupled to a first port of the valve, a pilot seat, and one or more cross-holes fluidly coupled to a second port of the valve; a pilot check member configured to be subjected to a fluid force of fluid in the channel of the pilot seat member acting on the pilot check member in a proximal direction; a solenoid actuator sleeve comprising a chamber; a first setting spring disposed in the chamber and configured to bias the solenoid actuator sleeve in a distal direction; and a second setting spring configured to bias the pilot check member in the distal direction, such that the first setting spring and the second setting spring cooperate to apply a biasing force in the distal direction on the pilot check member toward the pilot seat against the fluid force.

A pressure control device includes a body having a groove-shaped flow path including a groove part and a widened part, and a filter unit capturing foreign matters mixed in a fluid which passes through the groove-shaped flow path; the filter unit having a frame body including a through hole part and a filter member in a planar plate shape disposed with respect to the through hole part, and the filter unit being accommodated in the widened part. The frame body has: a first part having a first shape, a second part having a second shape smaller than the first shape, and a step part located at a boundary part between the first part and the second part The second part has a storage part provided in a penetrating manner on a bottom part side of the groove-shaped flow path and storing the captured foreign matters.

A system for operating a circle drive gear of a machine includes a pump configured to output pressurized fluid, an implement control valve fluidly coupled to the pump, a bi-directional hydraulic motor located downstream of the implement control valve and fluidly coupled to the implement control valve via a first delivery line and a second delivery line. The hydraulic motor has an output shaft that is configured to be rotatively driven by pressurized fluid output by the pump. A brake is disposed on the output shaft of the hydraulic motor and engages with the output shaft with the help of a spring force for reducing a rotational speed of the output shaft in a brake engage state. The brake operatively disengages from the output shaft in a brake release state with the help of fluid pressure in at least one of the first delivery line and the second delivery line.

A hydraulic buffer pertains to the field of hydraulic parts. A signal device (X) is installed at a position close to an end of a cylinder stroke to control movement of slide valves (12, 18, 12a, 12b, 12c, 12d, 12e, 12f, F1, F2, F3, F4) of the hydraulic buffer, to dynamically adjust the degree of valve openness and a liquid flow direction of a buffering module (Y), and therefore control pressure of oil entering an oil returning chamber of a cylinder. The high-pressure chamber of the cylinder releases pressure and unloads, and/or the oil returning chamber throttles to load pressure, such that a moving speed of a cylinder piston (6) at the end of the stroke is controlled, realizing buffering of the cylinder. The device eliminates defects in the prior art in which a buffering mechanism of a cylinder is complex, manufacturing accuracy requirements are high, structural arrangement is difficult, it is difficult to employ a combined configuration in which an oil returning chamber throttles to load pressure and a high-pressure chamber releases pressure and unloads, and buffering efficiency is not high. The device has desirable buffering controllability and high reliability, such that the overall quality is improved.

An example valve includes: a main piston comprising: a channel that is fluidly coupled to a first port of the valve, a pilot seat, and one or more cross-holes fluidly coupled to a second port of the valve; a pilot check member configured to be subjected to a fluid force of fluid in the channel of the main piston acting on the pilot check member in a proximal direction; a solenoid actuator sleeve comprising a chamber; a first setting spring disposed in the chamber and configured to bias the solenoid actuator sleeve in a distal direction; and a second setting spring configured to bias the pilot check member in the distal direction, such that the first setting spring and the second setting spring cooperate to apply a biasing force in the distal direction on the pilot check member toward the pilot seat against the fluid force.

A pressure-regulating valve has a valve piston (10) subjected to the action of an energy store and guided longitudinally in a valve housing (12). The valve housing has a supply port (14), a utility port (16) and a tank port (18) actuated by a control part (20) closing with a sealing action. In connecting from the supply port to the utility port, a pressure reduction function is realized. In a fluidic connection from the utility port to the tank port, a pressure-limiting function is realized. The control part (20) has a control rod (22) with two control bodies (24, 26) spaced apart from one another. One control body (24) controls the connection between supply port (14) and utility port (16). The other control body (26) controls the connection between utility port (16) and tank port (18).

A load-controlled hydraulic supply for an attachment attached to an agricultural tractor includes a hydraulic high-pressure source providing a volume flow in a supply line, a pressure-compensated control valve including an actuation device for adjusting the volume flow in the supply line, a return line leading to a hydraulic reservoir, and a load-indicating line. The volume flow is adjusted based on pressure feedback prevailing at the load-indicating line.