Electrohidraulica Rpm

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Festo Didactic GmbH & Co. Electrohydraulics

Electrohydraulic press

Motor with hydraulic pump Control panel Valve manifold CylinderThe hydraulic press is controlled via the electrical control panel.

Electrical signals are used to activate the valves in the hydraulic installation.

The electrohydraulic press is used to form rectangular troughs.

Control pane

Motor withhydraulic pump

Valve manifold

Actuator(cylinder)

Function units


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Festo Didactic GmbH & Co.

Electrohydraulic press


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Schematic layout of an electrohydraulic installation

Division of installation into signal control section and hydraulic power section.

Input and processing of electrical signals.

Solenoid valves form the interface between the electrical signal control section and

the hydraulic power section.

Controls the flow of hydraulic fluid by means of solenoid valves. Actuators convert

hydraulic energy into motions.

Signal control section

Signalinput

Hydrauliccylinder

Solenoidvalve

Hydraulicpowersupply(conversion)

Powersupply

Signalprocessing

Power sect on


Hydraulic power section


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Schematic layout of an electrohydraulic insta


Power secti


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Electrical power supply unit

Connection to mains supply.

Supplies signal control section with specified or maximum voltage and current

values.

Voltage transformation Rectification Smoothing Stabilisation Fuse protectionIn mobile hydraulic systems, rechargeable battery systems or generators are used

as a power supply for the signal control section.

230VAC

24VDC

TR

50 C

G C T T

Transformer Rectifier Smoothing Stabilisation Fuse

Functions in

power supply unit


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Electrical power supply unit

TR G C T


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Electrohydraulic converters (solenoid valves)

Convert electrical signals into hydraulic switching operations.

The switching armature is drawn into the coil, which acts as a magnet.

This produces a displacement of the actuating piston in the hydraulic 4/2-way valve.

A B

P T

Switching armature

4/2-way solenoid valve

BT A P L


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Electrohydraulic converters (solenoid valv


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Dry solenoids

wet solenoids

The solenoid is separated from the hydraulic fluid; a seal is required on the stem.

Simple construction

The armature chamber of the solenoid is filled with hydraulic fluid, the solenoid

operates in oil.

Low friction Little abrasion Good heat dissipation Long service life

seal

Dry solenoid Wet solenoid

Dry solenoid

Advantage

Wet solenoid

Advantages


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Dry solenoid Wet sol


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Solenoid valve connections

Solenoid with plug base Cable with connector socketElectrical signals are transmitted via standard connectors.

Reliable alignment of connections Connections can be attached and detached quickly Protected against dust and water

2

1

3

Protective earth connection

Plug base

Electricalconnections

Connector components

Advantages


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Solenoid valve connections


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Valve spool is directly actuated by solenoids.

The piston spool is displaced to the right and creates the connections P A

and BT.

Rest position produced by spring centring of piston spool. All inputs of the 4/3-way

valve are closed in this position.

T A P B

T A P B

A

a b

B

P T

a

a

b

b

Actuation on left

Rest position


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a

T A P B

T A P B


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4/3-way solenoid valve, piloted

Direct activation of pilot spool via solenoids.

The pilot piston spool is displaced to the right, and hydraulic fluid is directed to the

right-hand side of the main control spool, creating the connections P A and BT.

Rest position produced by spring centring of pilot and main piston spools. All ports

of the 4/3-way valve are closed at the main valve.

Simplified symbol

P T

A

A

B

B

P T

PB AT

Detailed symbol

Actuation on left

Rest position


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4/3-way solenoid valve, piloted

PB AT


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Electrohidraulica Rpm