Basic Of Hydraulic Cylinder
A Cylinder is actuator Which is Used to give unidirectional force through unidirectional Stroke. They are also known as jacks.
Cylinder Are Linear Actuators. This means that the output of a Cylinder is a straight – line motion and/ or Force. The major function of a Hydraulic Cylinder is to convert Hydraulic Power into linear mechanical Power.
There Are several types of Categories of hydraulic Cylinder which are explained below
Single Acting Hydraulic Cylinder attached Image
A Single- acting Cylinder Is pressurized on one end only. The opposite end is vented to tank.
This is the simplest actuator in the Ram Type . It has only one fluid chamber and exerts force in only one direction . Most are mounted vertically and retract by the force of Gravity on the Load . Practical for Long Strokes , Ram – Type cylinder are used in Elevators , Jacks and Automobile Hoists .
- Telescopic Cylinder
The Telescoping Cylinders are Single – Acting Cylinders . The Telescoping Cylinder is equipped with a series of nested tubular rod segments called Sleeves . These Sleeves work together to provide a longer working stroke than is possible with a standard cylinder . Up to Four or Five Sleeves can be used . The Maximum Load is Exerted when the cylinder is Collapsed . In the Extended position , The Load is a function of the diameter of the smallest Sleeve .
Double Acting Hydraulic Cylinder
The Double Acting Cylinder is the most common Type in industrial Hydraulics. Hydraulic pressure is applied to either port, giving powered motion when extending or retracting .
The majority of cylinder in use are basis double Acting Cylinders. These Cylinder are classed as Differential Cylinder because there are unequal areas exposed to pressure to extend and retract movements. The difference is caused by the cross-sectional area of rod which reduce the area under pressure during retraction.
Extension is slower than retraction because more fluid is required to fill the swept volume of the piston. However, greater force is possible because the pressure operates on the full piston area.
When retracting ,the same flow from a pump causes faster movements of the cylinder because the swept volume is less. With the same system pressure, the maximum force exerted by the cylinder is also less because the smaller area under the pressure.
Cylinder Construction and Operation
The Chrome Plated Steel Piston and Piston Assembly is the moving part . A cushion collar and plunger features are added to the assembly when cushions are desired . The Pressure – containing assembly is constructed of Steel cap or Blind – End Head , a Steel Body with Honed Finish , a rod – end head and the rod bearing .
Tie Rods and Nuts are used to hold the head and body together . Static Seals keep the joint pressure tight . The bearing is commonly retained with a plate and screws for easy removal . A Rod wiper is provided to keep foreign material from entering into the bearing seal area .
Sealing of moving surfaces is provided by the rod seal which prevent fluid from leaking along the rod , and by piston seals which prevent fluid from bypassing the piston .
Fluid is routed to and from the cylinder through ports in ends of the heads . The Cylinder rod will retract with pressure to the rod – end port and the other connected to the Drain . To extend the rod , pressure the cap – end port and connect the rod – end port to drain .
- Cylinder Mounting
The main Function of a cylinder mount is to provide a means of anchoring the Cylinder . There are a variety of ways to mount the cylinder including the Tie Rod , Bolt Mount , Flange , Trunnion , Side lug and Side Tapped and Clevis . The Tie rod is the Most common type of Industrial Mount .