Main parameters of hydraulic cylinders

The main parameters of the hydraulic cylinder include pressure, flow, size specifications, piston stroke, movement speed, push and pull force, efficiency and hydraulic cylinder power.

1.Pressure: Pressure is the pressure exerted by the oil on a unit area. The calculation formula p=F/A, that is, the load acting on the piston divided by the effective working area of the piston. From the above formula, it can be seen that the establishment of the pressure value is generated by the existence of the load. On the same effective working area of the piston, the greater the load, the greater the pressure required to overcome the load. In other words, if the effective working area of the piston is constant, the greater the oil pressure, the greater the force generated by the piston. The rated pressure we usually talk about is the pressure at which the hydraulic cylinder can work for a long time.

According to the rated pressure, the hydraulic cylinder pressure classification is shown in the following table: Unit: MPa

The maximum allowable pressure refers to the ultimate pressure that the hydraulic cylinder can withstand at an instant; and the pressure test pressure refers to the test pressure that the hydraulic cylinder needs to withstand when checking the quality of the hydraulic cylinder. Most countries stipulate that these two pressures are less than or equal to 1.5 times the rated pressure.

2.Flow rate: Flow rate is the volume of oil passing through the effective cross-sectional area of the cylinder per unit time. The calculation formula is Q=V/t=vA, where V represents the volume of oil consumed in one stroke of the hydraulic cylinder piston, t represents the time required for one stroke of the hydraulic cylinder piston, v represents the movement speed of the piston rod, and A represents the effective working area of the piston.

3.Piston stroke: The piston stroke refers to the distance traveled between the two poles when the piston reciprocates. Generally, after meeting the stability requirements of the cylinder, select a standard stroke similar to it from the table below according to the actual working stroke.

4.Piston movement speed: The movement speed is the distance that the pressure oil pushes the piston to move per unit time, which can be expressed as v=Q/A. The speed of the hydraulic cylinder should be appropriate. When the speed is too high, it often causes overheating and wear of the seal, and also aggravates the wear of the piston rod, guide sleeve and cylinder. When the speed is too low, it is easy to cause unstable conditions such as creeping. When using rubber seals, the maximum speed of the hydraulic cylinder should generally not exceed (24-30) m/min, that is, (0.4-0.5) m/s, and should not be lower than 6 m/min (0.1 m/s). It is a safe method to refer to the speed value of similar hydraulic cylinders.

5.Dimensions: Dimensions mainly include the inner and outer diameters of the cylinder, piston diameter, piston rod diameter and cylinder head size. These dimensions are calculated based on the use environment, installation form, required push and pull force and stroke of the hydraulic cylinder, and are rounded off from the table below after design and verification.