Hydraulic

HYDRAULIC COMPONENTS PUMPS

Gear pump A gear pump uses the meshing of gears to t o pump fluid by displacement. External gear pump design for hydraulic power applications.

Internal gear pump design for automotive oil pumps

Internal gear pump design for high viscosity fluids.

Rotary vane pump A rotary vane pump is a positive-displacement pump that consists of vanes mounted to a rotor that rotates inside of a cavity. The simplest vane pump has a circular rotor rotating inside a larger circular cavity. The centers of these two circles are offset, causing eccentricity. Vanes are allowed to slide into and out of the rotor and seal on all edges, creating vane chambers that do the pumping work.

Axial piston pump An axial piston pump is a positive displacement pump that has a number o f pistons in a circular array within a cylinder block . It can be used as a stand-alone pump, a hydraulic motor or an automotive air conditioning compressor.

Radial piston pump A radial piston pump is a form of hydraulic pump. The working pistons extend in a radial direction symmetrically around the drive shaft, in contrast to t he axial piston pump.

 ACTUATORS The actuators convert hydraulic energy to mechanical energy and are grouped as follows.

HYDRAULIC CYLINDERS

Double Acting Cylinders

Piston Rod

Cylinder Housing Fluid Ports Piston

Differential Cylinder

Non -differential Cylinder

Single acting cylinder

Load Port

Rod End

Air Vents Fluid Port

Piston Rod

Piston Rod Cylinder Housing Air Vents

Piston

HYDRAULIC MOTORS Gear Motor Piston Motor Vane Motor

Valves

Pressure control valves Valves control pressure in a hydraulic circuit

Pressure-relief valve. It is for limiting the pressure in a hydraulic system or in a part of the system. Pressure-relief valves limit the maximum pressure in a hydraulic circuit by providing an alternate path for fluid flow when the pressure reaches a preset level.

Pressure-reducing valve. This type of valve (which is normally open) is used to maintain reduced pr essures in specified locations of hydraulic systems. It is actuated by downstream pressure and tends to close as this pressure reaches the valve setting.

Unloading valve. Unloading valves are pressure-control devices that are used to dump excess fluid to the tank at little or no pressure.

Counterbalance valve. These normally closed valves are primarily used to maintain a back pressure on a vertical cylinder to prevent it from falling due to gravity

Pressure-sequence valve. A sequence valve is a pressure-control valve that is used to force two actuators to operate in sequence.

Brake valve.

Directional Control Valves Directional control valves control start/stop, directions, and acceleration/deceleration of hydraulic cylinders and motors. They can be used in v arious application

Designated by the number of service ports (control ports not included) and number of switching positions A valve with m service ports and n switching positions is thus designated as m/n way valve

Solenoid Operated Directional Valves These valves control the flow direction in hydraulic circuits, e lectrically operated with manual switches, limit switches, or pressure switches.

Solenoid Controlled Pilot Operated Directional Valves These valves are a combination of a small solenoid operated directional valve and a large pilot operated directional valve. The small four-way solenoid valve issued for directional control of the pilot line.

Check Valves These valves allow free flow in one direction, w hile preventing flow in the reverse direction.

Pilot Operated Check Valves These check valves have a pilot piston, which works with remote pressure to open the closed check valve.

FLOW CONTROL VALVES

These valves control flow rates in hydraulic circuits and are grouped as follows according to the control to be achieved in respective circuits

Restrictors/One Way Restrictors These valves regulate flow rates in hydraulic circuits. They have the advantages of plain structure, simple operation, and wide range of adjustment. On the other hand, they cannot accurately control the flow

Flow Control Valves/Flow Control and Check Valves These valves consist of a pressure compensator (pressure reducing valve that keeps the pressure difference constant) and a restrictor. They maintain a co nstant flow rate, independent of the inlet-outlet differential pressure.

Pilot Operated Flow Control and Check Valve These valves are pilot-operated. They control the flow with a hydraulic cylinder to accelerate or decelerate the actuator without shock.

MODULAR VALVES These valves, including the pressure control, flow control, and directional control types, have standardized mounting surfaces that conform to the ISO standards for solenoid operated directional valves. They are stacked on a base plate and referred to as sandwich valves or stack valves.

PROPORTIONAL ELECTRO-HYDRAULIC CONTROL VALVES These valves and related devices work with e lectrical settings to provide continuous remote control of the pressure and flow in hydraulic circuits.

 Accumulators Accumulators are a common part of hydraulic machinery. Their function is to store energy by using pressurized gas.

Filters Hydraulic systems may malfunction due to clogging and internal wear. With hydraulic fluids contaminated, hydraulic systems are damaged and fail to provide optimal performance. There fore, they require filtration to remove contaminants from the wor king fluids.