HIDROLIK DAN PNEUMATIK Pada sistem Mekatronika

Sistem transmisi Energi   

Sistem transmisi energi listrik Sistem transmisi energi mekanik Sistem transmisi energi fluida bertekanan

Fill the two syringes (plungers) and pipe with water, taking care to exclude any air. If you press down on one syringe the other will lift - even if you try to stop it

Uncompressible

If you fill the two syringes with air and repeat the experiment you will find that you can press down on one syringe and stop the other one moving by compressing the air inside

compressible

Contoh aplikasi pada alat berat

Hukum Dasar Hidromekanika Tekanan p Berdasarkan teori Pascal, jika sebuah gaya diterapkan pada sebuah luas an terhadap cairan dalam tabung tertutup, maka tekanan dari luasan tersebut akan diteruskan ke segala arah dengan besaran yang sama ke seluruh cairan tersebut. Force = F

F p A satuan ;1 Pa = N/m2 1 Pa = 10-5 bar

Luasan penampang = A

Diterapkan dalam silinder hidrolik (gerak linier)

F = force A =area p = pressure

F p A

F  p. A

F A p

Sistem hidrolik dasar

Sirkuit dasar Hydrolik

M

Pompa Hidrolik   

Gear pump Vane pump Piston pump

Centrifugal pump

External Gear Pump in Operation

Depending on the number of teeth, the "idler" gear might be driven directly by the "drive" gear. Generally with six or more teeth this is possible. In other cases an extra gear external to the pump drives the secondary gear at the same rate.

The teeth on Gear Pumps can be spur (straight), helical (slanted), herringbone, etc. There can be two, or more teeth on each gear -- twenty is not uncommon. The diameter of the gears and their thickness varies widely.

External Gear Pump

Lobe pump

Internal gear pump

Gerotor pump

Vane pump 

Two types of vane pumps are most often used:

• Balanced Vane Pumps • Unbalanced Vane Pumps 

The balanced vane pump is strictly a fixed displacement type. The unbalanced vane can have a fixed or a variable displacement.

Balanced Vane Pump

Balanced Vane Pump in Operation

UNBALANCED VANE PUMPS

UNBALANCED VANE PUMPS, fixed capacity

Variable capacity vane pump

Piston pump

The axial piston pump

In hydraulic systems with a working pressure above aprox. 250 bar the most used pump type is the piston pump. The pistons move parallel to the axis of the drive shaft. The swash plate is driven by the shaft and the angle of the swash plate determines the stroke of the piston. The valves are necessary to direct the flow in the right direction. This type of pump can be driven in both directions but can not be used as a hydromotor.

The axial piston pump with rotating swashplate.

The axial piston pump with rotating swashplate. Variable Displacement

Axial Piston Pump - Fixed Displacement

Axial Piston Pump - Fixed Displacement

Bent-Axis Axial Piston Pump

Bent-Axis Axial Piston Pump Fixed Displacement

Constant Bent Axis Axial piston Pump 

In this pump, the pistons are at an angle to the drive shaft and Thrust Plate. The piston block shaft is connected to the drive shaft by a universal t, not shown. The drive shaft, thrust plate, piston block shaft, and piston block all revolve.



The connecting rods are attached to the thrust plate and revolve with it, unlike the swash plate pump where the piston rods slide past a stationary swash plate.



The outlet ports are semi-circular holes in the Valve Plate, shown on the far right of the animation on edge and in a head-on view below, right.



As the pump revolves, half the pistons suck in fluid as they over the intake port. The other pistons discharge their fluid through the outlet port.

Radial piston pump

Piston pump with stationary cam and rotating block

Power calculation

(pressure in bar, flow rate in litres min -1)

pressure in psig, flow rate in gallons min-1

Filter

Sumber :Andrew A Parr, “Hydraulics and Pneumatics”, Elsevier, 1999

Pressure gauge

Pressure transd

Flow vs pressure

Energi Potensial

PRESSURE CONTROL VALVE

Pressure control valves are used to: • Limit system pressure • Reduce pressures • Set pressure at which oil enters a circuit • Unload a pump Fungsi : untuk mengendalikan tekanan secara otomatis yang terjadi dalam sistem hidrolik, sehingga tekanan yang besar tidak merusak sistem. Terdiri dari: 1. Unloading Valve 2. Pressure relief valve 3. Pressure reducing valve 4. Pressure Squence valve

RELIEF VALVES Each hydraulic system is designed to operate in a certain pressure range. Higher pressures can damage the components or develop too great a force for the work to be done. Two types of relief valves are used: DIRECT ACTING relief valves are simple openclosed valves.



PILOT OPERATED relief valves have a “trigger” which controls the main relief valve.



RELIEF VALVES Each hydraulic system is designed to operate in a certain pressure range. Higher pressures can damage the components or develop too great a force for the work to be done.

Two types of relief valves are used:

• DIRECT ACTING relief valves are simple open- closed valves.

• PILOT OPERATED relief valves have a “trigger” which controls the main relief valve.

Direct Acting Relief Valves, constant pressure

Adjustable Pressure Relief Valve manually operated

Pilot Operated Relief Valves When a relief valve is needed for large volumes with little pressure differential, a pilot operated relief valve is often used.

The pilot operated pressure relief valve

SIRKUIT RELIEF VALVE

Sirkuit pressure relief valve adjustable

F p A

F k x

PRV DIRECTLLY OPERATED

PRESSURE REDUCING VALVES A pressure reducing valve is used to keep the pressure in one branch of a circuit below that in the main circuit. Two Types of Pressure Reducing Valves Pressure reducing valves can operate in two ways: • Constant Reduced Pressure • Fixed Amount Reduction

p

T Ke tangki

Ke beban

Pressure Reducing Valve

DIRECTIONAL CONTROL VALVES Directional control valves direct the flow of oil in hydraulic systems. They include these types: 1. Check Valves 2. Rotary Valves 3. Spool Valves 4. Pilot Controlled Poppet Valves 5. Electro-Hydraulic Valves

ROTARY DIRECTIONAL VALVES

SPOOL DIRECTIONAL VALVES

Spool Valve Directing Oil to Cylinder

Symbol of a 4/3direction control valve

Katup kendali arah ISO 1219: Directional control valve 2/2 way valve normally closed

Jumlah port dalam satu kotak

Jumlah posisi / kotak

Directional control valve 3/2 way valve normally closed

A Directional control valve 3/2 way valve normally open

P S

A B Directional control valve 4/2 way valve

P

S

A

B

P

S

Directional control valve 5/2 way valve

Directional control valve 4/3 way valve

Logika kerja simbol katup kendali arah

A

1

0

P T

Mekanisme penggerak katup

MANUAL

Push/pull Button

Lever

Idle return roller

Spring

Pilot operated hydrolik

Pedal

Pilot operated pneumatik

Plunger

Signal elektrik

Roller

Signal elektrik proporsional

Detent

VOLUME CONTROL VALVES Volume control valves control the volume or flow of oil, usually by throttling or diverting it.

Basic Principle of Volume Control Valve

Katup kendali aliran

Throtle valve

Double-Acting Cylinder

Ram-Type Cylinder

Double-Acting Cylinder

1—Cup Packing 2—Flange Packing 3—U-Packing 4—V-Packing 5—Spring-Loaded Lip Seal

6—0-Ring 7—Compression Packing 8—Mechanical Seal 9—Non-Expanding Metallic Seal 10—Expanding Metallic Seal

Seals for Hydraulic Cylinders

SIRKUIT DASAR HYDROLIK

p2 =p1+10 bar

p1

Sirkuit pembatasan tekanan

Sirkuit pembatasan tekanan akibat inersia masa

Sirkuit tanpa tekanan

SIRKUIT METER-IN dan METER-OUT

SIRKUIT METER-IN

SIRKUIT METER-OUT

p1 p2

PNEUMATIC SYSTEMS In pneumatic systems, force is produced by air pressure acting on the surface of a piston. Air is a colourless, odourless and tasteless gas consisting of approximately 78% Nitrogen and 20% Oxygen. The remaining 2% consists of about 1% Argon and a mixture of other trace elements such as helium, hydrogen and neon. Air Compressed air is produced in a compressor and stored in a receiver. From here it is routed to valves which control the direction of fluid flow, flow control valves which control the amount of power produced by the cylinders which convert the potential energy of the compressed air into kinetic energy at the output. The physical behaviour of a fluid was first discovered by Blaise Pascal. Pascal found that when a force is applied to the end of a container of liquid, the force is transmitted

Blaise Pascal also discovered that pressure is equal to force per unit area (or the force divided by the area on which it acts)

Force = Pressure x Area

A force of 100 kPa (100 000 pascal's) is known as 1 bar. Normal atmospheric pressure ( the force exherted on a square metre of land at sea level by a square metre column of air rising from sea level to the outer atmosphere is approx 101.3 kPa (1.013 bar)

Air is pumped through a non-return valve into a strong metal tank called a receiver. When the air inside the receiver reaches, the required pressure (usually set on a regulator) the pump switches off. In case the regulator fails a safety valve is fitted to the receiver so that if a dangerous pressure is reached the safety valve opens to allow air to escape, reducing the pressure in the receiver.

PNEUMATIC SYSTEMS Pneumatics is all ing compressed air to 'make something happen'. Compressed air is simply the air we breathe squeezed into a small space under pressure. You might that air under pressure possesses potential energy which can be released to do useful work. You might also that a system is a group of components which work together to perform a task. A pneumatic system consists of a group of pneumatic components connected together so that a signal (compressed air) is ed through the system to make something happen at the output. Understanding pneumatics is really very simple. All you have to do is learn how a few basic components work. There are two main groups of components: Valves Cylinders

Cylinders are output components they cause something to move. Valves can be input or process components. If they are used as input components they introduce a signal into the system. If they are used as process components they decide what happens to the signal when it is recieved. Cylinders Cylinders convert the energy in the compressed air into linear motion. The air enters the cylinder and pushes a piston from one end of the cylinder to the other. There are two main types of cylinder:  Single acting  Double acting A single acting cylinder has only one air connection, whilst a double acting has two

With a single acting cylinder, the piston is pushed outwards by the pressure of the air. When the air supply is removed and the air inside the cylinder is allowed to escape (we call this the exhaust), the piston moves back, due to the compressed spring. It is possible to slow down the return movement of the piston, if we limit the rate at which the air can escape.

The double acting cylinder has two air connections. When compressed air is sent to one side and the other side is allowed to exhaust, the piston is pushed to one end of the cylinder. When air is then sent to the other side and the first side is allowed to exhaust, the piston is pushed back. This type of cylinder is more powerful on the return stroke than the single acting cylinder.

Directional Control Valves Valves receive external commands from a mechanical, pneumatic or electrical source and release, stop or re-direct the air that flows through them. Directional Control Valves can be used to provide a number of different functions. They can: •

Control the direction of cylinder movement;

•

Select the path air takes through the system;

•

Perform logic control functions;

•

Stop and start air flow (on-off valves);

•

Sense cylinder positions (limit valves)

Valves Valves control the switching and routing of air in a pneumatic system. Valves not only have to control the flow of the compressed air, they also have to control the flow of the exhaust to the atmosphere. There are two main types of valves used in pneumatic switching circuits: the 3/2 valve the 5/2 valve The 3/2 valve is used to control components such as single acting cylinders which have just one single input. The input to the cylinder is connected to port 2, the air supply to port 1 and port 3 is allowed to exhaust to atmosphere. The number 3 signifies that the valve has three ports, whilst the number 2 signifies that the valve has 2 directions or states

the 3/2 valve normally closed

The 5/2 valve is used to control components such as double acting cylinders which have two inputs. The inputs to the cylinder are connected to ports 2 and 4, the air supply to port 1. Ports 3 and 5 are allowed to exhaust to atmosphere. The number 5 signifies that the valve has five ports, whilst the number 2 signifies that the valve has 2 directions or states.

Component Symbols

SIRKUIT KENDALI LANGSUNG DAC

SAC

3/2 W.V.N.C 4/2 W.V.

SAC SIRKUIT KENDALI TIDAK LANGSUNG

DAC SIRKUIT KENDALI TIDAK LANGSUNG

SIRKUIT AND dan OR AND

x

y

A

1

0

0

0

1

0

1

1

1

0

0

0

SIRKUIT OR

x

y

A

1

0

1

0

1

1

1

1

1

0

0

0

KATUP THROTLE and CEK

SIRKUIT KENDALI KECEPATAN Kendali kecepatan maju SAC

Kendali kecepatan mundur SAC

Kendali kecepatan maju/mundur SAC

A

P

S

SIRKUIT KENDALI KECEPATAN DAC Sirkuit meter-in

Sirkuit meter-out

A

P

B

S

A

P

B

S

SIRKUIT BOLAK-BALIK KENDALI MANUAL DAC A

B

z

y

P

S

A

P

A

S

P

S

1.3

1.2 1.0 SIRKUIT BOLAK-BALIK KENDALI OTOMATIS MEKANIK DAC A

B

z

y

P

S

1.1

A

1.2

P

A

S

P

S

1.3

SIRKUIT TIME DELAY

1.0

1.3

A B

z

y P

1.2

1.1

S

1.5

A

A

z

P P

1.3

Sirkuit bolak-balik dengan penguncian melalui katup impulse dan or

Sirkuit bolak-balik dengan penguncian melalui katup impuls dan AND