The Comprehensive Guide to Hydraulic Cylinders

Automotive Lift Repair Florida Hydraulic cylinders, often referred to as hydraulic rams, harness the power of pressurized hydraulic fluid, typically hydraulic oil, to perform their functions. 

An Automotive Lift Repair Florida hydraulic cylinder consists of a barrel in which a piston, attached to a piston rod, moves back and forth. The piston is equipped with sliding rings and seals, dividing the cylinder into two chambers: the cap end and the rod end. The hydraulic pressure applied to the piston generates linear force and motion.

Components such as flanges, trunnions, and clevises are mounted on the cylinder body, while the piston rod features mounting attachments to connect the cylinder to the machinery it operates.

Automotive Lift Repair Florida Hydraulic cylinders function as the actuator or “motor” within a hydraulic system. The hydraulic pump, on the other hand, serves as the “generator,” supplying a fixed or regulated oil flow to the cylinder’s base, which moves the piston rod upward. The piston then pushes hydraulic oil from the other chamber back to the reservoir. The force exerted on the piston rod equals the pressure in the cylinder multiplied by the piston area (F=PA), assuming the oil pressure in the rod end chamber is near zero.

In this case, the pressure in the rod end chamber is calculated by (Pull Force) / (Piston Area – Piston Rod Area).

Automotive Lift Repair Florida Hydraulic cylinders are essential for applications requiring linear motion to move, lift, or lock heavy loads. They convert hydraulic pressure and oil flow into mechanical force, making them integral to various industries. While hydraulic cylinders and hydraulic motors both convert fluid power into mechanical energy, cylinders are distinct for their linear movement, earning them the designation “linear motors.”

Constructed to handle high pressures, Automotive Lift Repair Florida hydraulic cylinders are made from robust materials like steel to endure the forces involved. They are available in various designs, including tie rod and welded body cylinders, and can be categorized into types such as telescopic, plunger, differential, re-phasing, and single and double-acting cylinders.

Tie Rod Style Hydraulic Cylinders

Tie rod cylinders use high-strength threaded steel rods to secure the end caps to the cylinder barrel. This construction method is common in industrial applications, with smaller cylinders typically using four tie rods and larger ones requiring up to 16 or 20. NFPA standards ensure compatibility between different manufacturers’ cylinders, and these cylinders can be fully disassembled for maintenance.

Welded Body Hydraulic Cylinders

Welded body cylinders eliminate the need for tie rods by welding the barrel directly to the end caps and ports. This design results in a narrower body and can accommodate tight spaces in machinery. Welded cylinders are less prone to tie rod stretch and can be customized with special features. They are prevalent in mobile hydraulic equipment and heavy industry applications.

Parts of a Hydraulic Cylinder

– Cylinder Barrel: A thick-walled forged pipe, internally machined and often ground or honed.

– Cylinder Bottom (Cap): Joins the barrel and can be welded, screwed, or flanged.

– Cylinder Head: Connects to the barrel via a lock, screws, or flanges.

– Piston: Separates the cylinder into chambers and is equipped with seals to manage hydraulic oil pressure.

– Rod Gland: A hard, chrome-plated steel rod extending through the cylinder, connecting to the machinery.

Automotive Lift Repair Florida Piston Rod Construction

The piston rod operates within and outside the cylinder and is often coated with chromium or stainless steel for corrosion resistance. In marine environments, nickel and chromium coatings or solid stainless steel may be used. Ceramic coatings are also available for enhanced durability.

Rephasing Hydraulic Cylinders

Cylinders can be arranged in parallel or series, with bores and rods sized to ensure synchronized extension and retraction. This setup eliminates the need for flow dividers or mechanical connections between cylinders.

For more technical details on hydraulic cylinders or to find the best solution for your needs, visit our Hydraulics Glossary or reach out to us directly.

The Importance of Hydraulic Cylinder Seals in a Hydraulic System

Hydraulic cylinder seals are essential components in systems where parts come into contact with liquids. They are crucial for converting hydraulic power into linear motion within the hydraulic system.

These seals are made from various materials, including rubber and polyurethane. Although durable, they can fail or cause significant damage if not properly set up. Factors such as oil contamination, high temperatures, chemical erosion, or improper installation can lead to seal failure, which can negatively impact the entire system.

Oil Contamination

Oil contamination is a major cause of hydraulic cylinder seal failure. Contaminants can lead to internal leakage and compromise flow and pressure control in valves, potentially wasting horsepower and causing system overheating. A rod wiper can help prevent contamination as the rod retracts. Proper filtration of hydraulic oil is essential to avoid contamination, and any signs of a scratched rod, extreme seal wear, or oil leaks should prompt immediate cleaning of the oil.

High Temperature

If Automotive Lift Repair Florida hydraulic cylinder seals become hard and brittle or if the seal lip or body shows signs of erosion, the oil temperature in the cylinder may be too high. Prolonged exposure to high temperatures can cause seals to lose functionality due to excessive compression or damage. This can result from seals being made from inappropriate materials, excessive friction, or close proximity to heat sources.

Chemical Erosion

Using unsuitable materials for hydraulic cylinder seals can lead to chemical breakdown. Chemical attacks from oil additives on incompatible seal materials can degrade the seal’s components, leading to issues such as loss of seal lip integrity, swelling, or shrinkage. Chemical breakdown can also manifest as discoloration of the seals.

Inadequate Installation

Improper installation of hydraulic cylinder seals is a common cause of system failure. It is crucial to clean the equipment thoroughly before installation, avoid damaging or scratching the seals, and ensure proper lubrication of the system. Issues such as a seal gland being too tight or obstructing the seal lip can cause problems. Careful attention during installation can prevent issues such as seals being installed upside down.