The Hyraulic cylinders for excavator is the executing component of the hydraulic system, which is an energy conversion device that converts hydraulic energy into mechanical energy. It is like the "muscles" and "joints" of an excavator, directly determining the strength, speed, accuracy, and reliability of the entire machine. This article will provide a comprehensive and in-depth analysis of hydraulic cylinders used in excavators.

Excavator hydraulic cylinder is a mechanical device that uses the pressure energy of hydraulic oil to generate linear reciprocating motion (or swinging motion). On excavators, it is usually composed of main components such as cylinder barrel, piston, piston rod, end cover, and seals.

In the power transmission chain of excavators, the engine is the "heart" that provides the original power; Hydraulic pumps are "arteries" that convert mechanical energy into hydraulic energy; The control valve is a "neural network" that accurately distributes the flow direction of oil; And hydraulic cylinders (and hydraulic motors) are the "limbs" that ultimately convert energy into mechanical action. Without hydraulic cylinders, even the most sophisticated hydraulic system cannot do work.

The Importance of Excavator Hydraulic Cylinder Reflects

Implementing core functions: The three basic actions of the excavator - the lifting and lowering of the boom, the extension and retraction of the boom, and the excavation and unloading of the bucket - are completely driven by three main sets of hydraulic cylinders (boom cylinder, boom cylinder, and bucket cylinder). Walking and rotating mechanisms may also use hydraulic cylinders (such as walking tensioning cylinders).

Providing enormous working force: Thanks to Pascal's principle, a small hydraulic pressure can generate a huge thrust or tension on the piston. This allows excavators weighing tens of tons to unleash digging forces of hundreds or even thousands of newtons.

Ensure precise control: By controlling the flow into the oil cylinder through a precise proportional valve, the piston rod can be extended and retracted extremely smoothly, allowing the driver to complete high-precision operations such as fine leveling and threading.

Carrying severe working conditions: The oil cylinder directly bears the huge impact load and unbalanced load during the excavation process, and its structural strength and durability are the key guarantees for the reliability of the whole machine.

Almost all excavator hydraulic cylinders use double acting cylinders, which means hydraulic oil can be alternately supplied to both sides of the piston to achieve movement in two directions.

Extension stroke: When pressure oil enters from the rodless chamber oil port, hydraulic oil pushes the piston and drives the piston rod to extend outward. At this point, the oil in the rod chamber is squeezed out by the piston and flows back to the oil tank. This process generates the maximum thrust (due to the large effective area of the piston).

Retraction stroke: When pressure oil enters from the rod chamber oil port, the hydraulic oil pushes the piston and drives the piston rod to retract. At this point, the oil in the rodless chamber is pressurized back into the tank. The tension generated during this process is relatively high, but the movement speed is faster (due to the small volume that needs to be filled on one side of the rod cavity).

Types and Applications of Hydraulic Cylinders for Excavators

According to the installation position and function on the excavator, it is mainly divided into three categories:

Boom Cylinder: usually two, connected between the lower frame and the boom. Mainly responsible for the lifting and lowering of the boom, it is the main source of force for lifting heavy objects and determining excavation depth. Its characteristics are long stroke, thick cylinder and rod diameter, and maximum load-bearing capacity.

Arm Cylinder: Typically one or two, connected between the boom and the arm. Mainly responsible for the extension and retraction of the boom, and is the main executor of the excavation action. It frequently undergoes reciprocating motion, bearing huge impact loads and biased loads, and has extremely high durability requirements for the sealing system.

Bucket Cylinder: Typically one, connected between the boom and bucket. Mainly responsible for controlling the excavation and unloading actions of the bucket. Its movement is the most frequent and often in the extreme working position, requiring high requirements for buffer design.

In addition, there are auxiliary cylinders such as walking tension cylinders used to adjust the tension of the tracks.

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