8/3/2019 Application of Proportional Hydraulics

http://slidepdf.com/reader/full/application-of-proportional-hydraulics 1/6

APPLICATION OF PROPORTIONAL HYDRAULICS

The force of clamping machine used to clamp work-pieces of different kind of materials, needs a

number of pressure pre-sets which is selectable by pressing a number of pushbuttons.

The extension speed of a soft stamping machine has to be fast to reduce idle time. The stamping

effect on the surface of the material has to be soft.

8/3/2019 Application of Proportional Hydraulics

http://slidepdf.com/reader/full/application-of-proportional-hydraulics 2/6

APPLICATION OF PROPORTIONAL HYDRAULICS

The table of a surface grinding machine has to move continuously under a grinding machine. The

table must decelerate when it is about to reach the end position, reversal gently and accelerate in

the opposite direction.

Different pressures are to be set on an injection moulding machine. The plastifying cylinder, fills

the mould with low filling pressure and completes the filling with a higher pressure. The cylinder 

is to retract at low pressure.

8/3/2019 Application of Proportional Hydraulics

http://slidepdf.com/reader/full/application-of-proportional-hydraulics 3/6

APPLICATION OF PROPORTIONAL HYDRAULICS

The hydraulic passenger lift must accelerate from stand still and decelerate to a stop to avoid

 jumping and dropping effect to the passenger.

Honing machine require infinitely adjustable reverse points to suit the dept of the bore.

8/3/2019 Application of Proportional Hydraulics

http://slidepdf.com/reader/full/application-of-proportional-hydraulics 4/6

PROPORTIONAL HYDRAULIC SYSTEM

Electrical and hydraulic signal flow 

INPUT

Components that produces ELECTRICAL SIGNAL upon actuation

TYPES OF ELECTRICAL SIGNAL

1.  Binary signal

- hanya boleh ON-OFF sahaja.

y  ada signal 24v

y  tiada signal ± hanging (voltage)

2.  Analogue signal

y  hanya boleh guna dalam PH

y  Boleh hasilkan signal secara berterusan

A binary signal has only two values

VALUE ± O volt, VALUE ± 24 volt

8/3/2019 Application of Proportional Hydraulics

http://slidepdf.com/reader/full/application-of-proportional-hydraulics 5/6

Components that produces binary signals are

1.  Pushbutton switch

2.  Roller limit switch

3.  Pressure switch

4.  Proximity sensor 

Components that produces analogue signals are

1.  Analogue pressure sensor 

2.  Analogue temperature sensor 

3.  Linera potentiometer 

4.  Proximity sensor 

Process

Components that are used to create LATCHING and LOGIC FUNCTION

Processing components are relays and PLC.

A relay is an electrical component that consists of a coil and a set of contacts.

A PLC is a controller that can be programmed to provide logic functions.

Set point card

Specifies set point voltage for the amplifier 

8/3/2019 Application of Proportional Hydraulics

http://slidepdf.com/reader/full/application-of-proportional-hydraulics 6/6