An automatic depressurizing pump includes an air-generating unit and an airflow control unit. The air-generating unit has a first air intake hole. An air generated by the air-generating unit drives the air control unit so as to inhale or exhale airflows through the first air intake hole. The airflow control unit includes a valve base, a first valve, a second valve, a top cover, and a resilient member. The valve base includes an air output chamber and a pressure chamber. The resilient member includes a second air output hole and a depressurization valve. The second air output hole is communicated with the top of the air output chamber, and the depressurization valve hermetically covers on and fixes to the top of the pressure chamber.

Embodiments provide for two rotating parallel discs to power horizontal pistons back and forth configured in a radial pattern, comprised of double acting fluid end that may be used in high pressure fluid handling equipment, wherein the fluid end has an arrangement that acts upon both a suction and a discharge operation.

A fluid end assembly of a hydraulic fluid pump includes a housing having a bore, a removable valve cover closing the bore, and a retainer engaging the bore. The retainer includes a set screw bore that extends from a first side of the retainer to a second side of the retainer, opposite the first side. The fluid end assembly further includes a set screw. The set screw is threaded into the set screw bore from the first side of the retainer. The set screw is not removable from the second side of the retainer. The first side of the retainer is positioned adjacent to the valve cover.

A fluid end assembly of a hydraulic fluid pump includes a housing having a bore, a removable valve cover closing the bore, and a retainer engaging the bore. The retainer includes a set screw bore that extends from a first side of the retainer to a second side of the retainer, opposite the first side. The fluid end assembly further includes a set screw. The set screw is threaded into the set screw bore from the first side of the retainer. The set screw is not removable from the second side of the retainer. The first side of the retainer is positioned adjacent to the valve cover.

An inclined-axis axial piston machine includes a housing, a drive shaft and a cylinder barrel. The drive shaft is mounted in the housing so as to be rotatable with respect to a first axis of rotation and is integral with a flange. Each piston is coupled to the flange via a ball joint. A multiplicity of counting perforations are arranged in a periodically distributed and continuous manner over an outer circumferential surface of the flange. The housing accommodates a sensor arranged opposite the counting perforations such that rotation of the drive shaft causes a signal change at the sensor. Each counting perforation is formed integrally from the flange, in the form of a recess having a single continuous perimeter. A side wall of the recess, starting from the perimeter, extends uninterruptedly, without sharp bends or offsets, over the entire circumference of the perimeter.

An inclined-axis axial piston machine includes a housing, a drive shaft and a cylinder barrel. The drive shaft is mounted in the housing so as to be rotatable with respect to a first axis of rotation and is integral with a flange. Each piston is coupled to the flange via a ball joint. A multiplicity of counting perforations are arranged in a periodically distributed and continuous manner over an outer circumferential surface of the flange. The housing accommodates a sensor arranged opposite the counting perforations such that rotation of the drive shaft causes a signal change at the sensor. Each counting perforation is formed integrally from the flange, in the form of a recess having a single continuous perimeter. A side wall of the recess, starting from the perimeter, extends uninterruptedly, without sharp bends or offsets, over the entire circumference of the perimeter.

The invention relates to a metallic work-piece (2, 5, 6, 14, 20, 23) for a hydraulic device (1, 15). The workpiece (2, 5, 6, 14, 20, 23) comprises a coating layer (12), characterized in that the coating layer (12) contains Mo, in particular metallic Mo, with a weight fraction of at least 1%.

The invention relates to a metallic work-piece (2, 5, 6, 14, 20, 23) for a hydraulic device (1, 15). The workpiece (2, 5, 6, 14, 20, 23) comprises a coating layer (12), characterized in that the coating layer (12) contains Mo, in particular metallic Mo, with a weight fraction of at least 1%.

A pump displacement control device includes: a servo piston that changes a tilt angle; a flow rate control spool that is displaced corresponding to an input pressure; a power control spool that is displaced corresponding to a discharge pressure of the pump; a control pressure regulating spool that regulates a control pressure which controls the servo piston; and a feedback lever connected to the servo piston and the control pressure regulating spool. The feedback lever directly abut on either one of the flow rate control spool or the power control spool for regulating the control pressure.