What is Hydraulic cylinder: Definition and 25 Discussions

A hydraulic cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in construction equipment (engineering vehicles), manufacturing machinery, and civil engineering.

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  1. S

    Find the diameter of the piston at certain heights

    I solved for part A by using the equation r2 = sqrt(m2/m1) * r1 im having trouble solving for part B, I know that you would use the equation F1/A1 = F2/A2 + pgh and solve for r2, but when I solved for r2, I got an undefined number. Can someone run me through this question?
  2. M

    "KICK" force exerted from a hydraulic cylinder

    Hello,I am building a press that will squeeze hot steel ,back off .5"push hot steel in further and repeat.The cylinder is 4" bore , 1.375"rod and travel is 8" (the majority of squeeze will be at 5"of extension)at a max of 2500PSI. my question is when putting @15 tons straight down what will the...
  3. S

    How to determine the force on the linkage

    hi Wondering if someone could help. I need to know how to work out the the force at point 'A' ( see sketch attached). Its a door opening and closing mechanism and it consists of a hydraulic cylinder 32mm dia bore operating at 140 bar. The door is opened and closed via couple of linkages as the...
  4. I

    Force Calculation -- Hydraulic cylinder and a rotating arm

    Hi There, Long time reader, first time poster.. I hope someone out there can help me. I'm designing an add-on to an existing piece of equipment and I'm unsure of how to calculate the resultant force output from a hydraulic cylinder. On a straight push, the chosen hydraulic cylinder has an...
  5. Wale

    Motor driven hydraulic cylinder design

    I am trying to design a mechanism which has a hydraulic cylinder driven by a step motor. The motor shaft is connected to the hydraulic cylinder piston via two rods of lengths r and L as shown in the below figure. I want the cylinder's piston to be driven at constant velocity v, so I am trying to...
  6. S

    Seal friction needed for pneumatic/hydraulic piston

    Hello, I have a project that requires me to calculate break force friction of a piston seal on the cylinder wall. I have a double acting cylinder at very low pressure, 3.5" diameter bore, one side of the piston is air, the other side is water. What seal type, seal compression, lubrication and...
  7. jack action

    Sizing hydraulic (brake) lines

    On older GM cars, the brake lines are 3/16" from the front port of the master cylinder, splitting into two 3/16" for each front wheel, and 1/4" from the rear port of the master cylinder, splitting into two 3/16" for each rear wheel. This is the case for drum/drum or disc/drum configurations...
  8. N

    Annulus force in a Hydraulic Cylinder?

    Hi, I was wondering if I could ask for some advice. I'm was calculating the Annulus force that a hydraulic cylinder could generate that I've been asked to do some work on, however this particular ram is a little unusual in that it had a split rear piston and necks down to a smaller diameter than...
  9. R

    I Calculating FvD for Hydraulic Cylinder with Air Bubble

    I want to calculate the force-displacement curve for a damper that would have hydraulic oil with an air bubble in it, so very similar to an air spring with a limited amount of volume. I came up with the following solution: F(x)=Po*A((Vo/Vo-A*x)-1) where F would be the external force applied...
  10. M

    Temperature rise due to cycle test

    Hello all, I am working on a few test scripts to test the life of a hydraulic cylinder. (It is a mechanically operated cylinder and has a positive displacement) The testing will involve thousands of continuous pump and retraction operations, due to which the temperature of the piston seal and...
  11. cjpa

    A Understanding Force Diagrams for Hydraulic Cylinder Selection

    Hello world, I have to select an hydraulic cylinder to counter-balance a force. For that purpose I need to know the force that my hydraulic cylinder must exert. Typically I would use the horizontal part of F2, but being that force with diferent degrees, doen't my friction play an important...
  12. G

    Hydraulic cylinder speed/force

    Hi, I've been reading up on hydraulic fluid power design to design a lifting system for a loader bucket I'm building for my 20Hp tractor. I know how to calculate the force/ speed of one cylinder extending; but I am a little lost as far as using two cylinders. If I have a total weight of 2000...
  13. George Zucas

    Hydraulic Cylinder Loading Conditions

    Hello, I am working on a hydraulic cylinder application that will lift some weight that is not aligned with the axis of the cylinder. Take a look at the picture and imagine that instead of ropes there is a hydraulic cylinder fixed to the beam doing the lifting. The load creates moment since it...
  14. J

    Hydraulic cylinder (Shell) stresses

    Hello guys, this is my first time here take an apology if I choose wrong section of forum. I just want to know should in shell of double-acting hydraulic cylinder (as in hydraulic presses ) should longitudinal/axis stress be analyzed beside radial and Circumferential/hoop stress and take in...
  15. O

    Psi question about a hydraulic cylinder

    Homework Statement A hydraulic log splitter with a maximum operating pressure of 3000 psi is powered by a 5 hp hydraulic engine. If the log splitter is capable of generating a maximum nominal force of 10 tons (20000 lb) what is the effective diameter of the hydraulic cylinder? What is the...
  16. P

    Calculating hydraulic cylinder size wind turbine tower

    Hello, I could use some help determining what size hydraulic cylinder I need to be able to tilt my turbine tower up. What I have is a 70 ft tower where the first 20 feet weigh 2500 lbs, the 2nd 20 weigh 1700 lbs and the 3rd 20 ft weigh 1000 lbs and the last 10 feet weigh 1000 lbs. For a total...
  17. S

    Flow rate vs pressure relationship in a hydraulic cylinder

    Hi all, I need to model an hydraulic cylinder with simulink and to control it according to some rules. What I don't understand is to find a relationship between the flow rate and pressure inside it. Any suggestion is appreciated. Thanks
  18. S

    Can I get a 40KN force from a hydraulic cylinder powered by an electric motor?

    Im thinking of designing a tipping trailer for a car. I need a force of 40KN exerted to tip but would this be too much for driving with an electric motor powered by the car battery. If not what size of motor and pump would I need? thanks
  19. C

    Calculating force of hydraulic cylinder

    I want to calculate the force generated (as a result of expanding air) from pressure created by heating air up to a maximum temperature of 800 degrees Celsius. My flywheel with a radius of 0,030m is rotating at a speed of 850RPM and weights 0,27Kg. Angular velocity: w=850RPM*(2pi/60)=89rad/s...
  20. M

    Can Hydraulic Cylinders Be Driven by Refrigerants or Steam?

    Hi, I posed some questions regarding the use of hydraulics before in this forum, and this time I would like to know if it is technically possible to use refrigerants or steam to drive a hydraulic cylinder. It's part of an organic rankine energy generation project I'm hoping to attempt. I have...
  21. J

    Calculate Pressure in Hydraulic Cylinder

    hey everyone, can someone please help me out with this one, I am a bit stuck with this using the law F = PXA and F = mxa calculate the pressure in a hydraulic cylinder, when the load of 375kg, is applied to the piston piston diameter it 95mm so far what i have worked out is as follows...
  22. M

    Energy balance in hydraulic cylinder

    hello everyone, In a hydraulic cylinder high amount of load is lifted by applying lower loads in smaller diameter side.. for example, if the diameters of two cylinders is 2cm and 4 cm and i applied a force of 10 N on the 2cm cylinder for 4m downwards. so now the 4cm diameter cylinder could...
  23. M

    What is the life (in cycles) for a hydraulic cylinder

    Does anyone know how many cycles (extend / retract) that a hydraulic cylinder should be able to do before needing repair? The specifics for the cylinder are that there is minimal (almost none) low frequency and low amplitude pulsing of pressure. The cylinder will cycle once every 5 minutes...
  24. J

    Finding strains and stresses on a hydraulic cylinder - NO external pressure?

    I'm running a test simulation on a Festo rig, with a hydraulic cylinder measuring 45mm internal diameter and 54mm external diameter. The testing requires an internal pressure of 60Bar with no external pressure applied. The strain gauge and setup I'm running it on I suspect to be faulty, and I...
  25. M

    Solving Hydraulic Cylinder Issue: 100N Force at 4m/sec, Stroke 128mm

    hi everyone, i am a new entrant to this forum. can anyone help me to solve this issue. i have a hydraulic cylinder arrangement which delivers 100N force at 4m/sec with a stroke length of 128mm. i need to convert this linear force to run a cylindrical roller. what will be the torque it...