Roger C. Ellis ECE Mechatronics Assignment #1

Outline  Reference list  Major applications  Working principle  Example in field  Specifications  Limitations  Where to find

Reference list  Yiding Han – working illustration  Grainger Products  Peninsular Cylinder  Northern Tool & Equipment  Dalton Hydraulic Cylinders  Fluid Power's Hydraulic Outlet

Web references  distributors.php distributors.php  er er  muenchen.de/konferenzen/Jass06/courses/5/ Papers/Ponomareva.pdf muenchen.de/konferenzen/Jass06/courses/5/ Papers/Ponomareva.pdf  ures/L7.pdf ures/L7.pdf

Major applications  Industry Hydraulics  Agricultural Hydraulics  Mining Hydraulics  Construction Hydraulics  Marine Hydraulics  Oil & Gas Hydraulics  Forestry Hydraulics

Basic Working Principle  Hydraulic actuators or hydraulic cylinders typically involve a hollow cylinder having a piston inserted in it. The two sides of the piston are alternately pressurized/de- pressurized to achieve controlled precise linear displacement of the piston and in turn the entity connected to the piston. The physical linear displacement is only along the axis of the piston/cylinder.hydraulic cylinders

Parts of a hydraulic actuator  Cylinder Barral - barrel is mostly a seamless thick walled forged pipe that must be machined internally  Cylinder Bottom & Head – typically the barrel and the bottom are welded together, screwed together, or flanged  Piston - cylinder-shaped metal component that separates the two sides of the cylinder barrel internally, the piston is usually machined with grooves to fit O-rings, U-cups or cast iron rings that will create a seal between the two chambers. These two chambers also for different pressures so that the piston can extend and retract.  Piston rod - The piston rod connects the hydraulic actuator to the machine component doing the work. Can have a single connection to the piston or two connection points.

Hydraulic Actuator Designs  Tie Rod - Tie rod style hydraulic cylinders use high strength threaded steel rods to hold the two end caps to the cylinder barrel. This method of construction is most often seen in industrial factory applications. Small bore cylinders usually have 4 tie rods, while large bore cylinders may require as many as 16 or 20 tie rods in order to retain the end caps under the tremendous forces produced. Tie rod style cylinders can be completely disassembled for service and repair  Welded Body - have no tie rods. The barrel is welded directly to the end caps. The ports are welded to the barrel. The front rod gland is usually threaded into or bolted to the cylinder barrel. This allows the piston rod assembly and the rod seals to be removed for service.

Advantages  Very high force applications  Welded body are narrow and short for compact apps.  infinitely variable control of gear-ratio in a wide range and an opportunity to create the big reduction ratio  small specific weight  With high-bandwidth pressure  Usually designed to withstand heavier pressures  High positioning stiffness  responds fast since disturbances propagate in oil about four times faster than in air

Working Illustration

Sample Configuration 1  An excavator has many hydraulic actuators, can you identify them all?

Sample Configuration 2  When your car is getting fixed or parts replaced, a hydraulic actuator system is used to lift your car off the group and allow technicians and mechanics fix the problem

Major Specifications  Power-to-mass ratio  Power-to-volume ratio  Backdrivability  Minimal static friction  Low actuator inertia

Choosing an actuator  What is your application?  How much movement do you need?  How much pressure (power) do you need to move your application?  Other constraints  Temperature  Environmental factors  Types of particle debris can affect performance  cost

Limitations  High Price  Not efficient in low energy output  Oil must be continuously filtered and cleaned  even very small particles can cause the system to lock up  Oil leak do occur  -In the worst case, high pressure oil leaks are a safety hazard

Retailers and Costs  Grainger : $200-$1000+  ndex.shtml ndex.shtml  Peninsular Cylinder : $460 - $869   Made to order so price will vary  Northern Tool & Equipment : $80 - $520  /servlet/category_6970_96+425

Retailers and Costs  Dalton Hydraulic Cylinders : $60 - $620   Fluid Power's Hydraulic Outlet: $80 - $380 