XNUMX. The following technical parameters need to be confirmed for hydraulic cylinder customization

1, The working pressure of the hydraulic cylinder (MPa) Or the actual force of the hydraulic cylinder (tons/kg)
Low pressure hydraulic cylinder 0~3.5MPa
Medium and low pressure hydraulic cylinder 0~7.0MPa
Medium pressure hydraulic cylinder 7.0~14.0MPa
High pressure hydraulic cylinder 14~21.0MPa
Ultra-high pressure hydraulic cylinder above 21MPa

2, Hydraulic cylinder type selection
Single-acting hydraulic cylinderXNUMX. The following technical parameters need to be confirmed for hydraulic cylinder customization

1, The working pressure of the hydraulic cylinder (MPa) Or the actual force of the hydraulic cylinder (tons/kg)
Low pressure hydraulic cylinder 0~3.5MPa
Medium and low pressure hydraulic cylinder 0~7.0MPa
Medium pressure hydraulic cylinder 7.0~14.0MPa
High pressure hydraulic cylinder 14~21.0MPa
Ultra-high pressure hydraulic cylinder above 21MPa

2, Hydraulic cylinder type selection
Single-acting hydraulic cylinders are only used when the return stroke is achieved by mechanical means such as dead weight, external load or spring force, and double-acting cylinders are generally used.

3, Hydraulic cylinder parameter selection
Cylinder inner diameter, piston rod diameter, stroke, cylinder speed, oil port diameter

4、Cylinder tube and cylinder head structure selection
Generally, tie rod type and screw type are used for general machinery and equipment, and welding type is used for heavy cylinders and high pressure large diameter cylinders of metallurgical machinery, forging machinery, etc.

5, Hydraulic cylinder installation and connection method
Including flange type, pin type, earring type, base type, ball head type, refer to YGD series tie rod hydraulic cylinder, HSG engineering hydraulic cylinder, Y-HG1 metallurgical hydraulic cylinder

6, The choice of buffering device
When the operating speed of the hydraulic cylinder reaches a certain standard after being loaded, a hydraulic cylinder with a buffer device must be selected.Or when reaching a higher speed, a reduction valve must be installed outside the hydraulic cylinder.

7, The choice of sealing device
Choose hydraulic oil and oil seal carefully.Different hydraulic oils are suitable for oil seals of different materials to ensure the service life of hydraulic cylinders.

FAQ

1. Customized cylinders usually need to communicate clearly on technical requirements between the two parties;

2. The drawings newly designed by Jinyunbo must be confirmed in writing by the customer before processing

The main parameters of hydraulic cylinder

1. Cylinder inner diameter D

It can be calculated according to the required output force F, hydraulic system set pressure p and hydraulic cylinder mechanical efficiency ηm according to the relevant formulas in Table 4-1, but in the end, the value that meets the national standard GB2348-1993 must be selected in order to select the standard Products and standard seals

2. Piston rod diameter d
The diameter of the piston rod must be large enough to withstand the load and the stress applied by the cylinder.When the piston rod is under tension, the area of ​​the piston is equal to the piston force divided by the yield limit of the piston rod and multiplied by the safety factor.However, when the piston rod is subjected to thrust, it must have sufficient longitudinal bending strength.When the longitudinal bending strength is not enough and large deflection is generated, the friction of the sliding surface causes a large bias load on the guide sleeve and the piston, causing problems such as jamming, crawling, and abnormal wear of the seal.The additional strength required to prevent longitudinal bending depends on the stroke and the fulcrum connection method
3. Itinerary S
The stroke S of the cylinder depends on the distance of the load movement.When the stroke is long, the piston rod needs to be thicker, and a stop sleeve may be installed in the cylinder to improve the ability to resist longitudinal bending
4. Cylinder speed υ
The determination of the cylinder speed υ is related to the cycle time and the stroke of the cylinder.The generally recommended speed range is 15～300mm/s.Excessive cylinder speed will shorten the life of the seal.When the speed is too low, it is easy to crawl and cannot work smoothly.
5. Oil port diameter d0
The oil port diameter d0 should be determined according to the cylinder speed and piston area.The flow rate of the oil port should not exceed 5m/s, so as not to affect the output force of the cylinder due to excessive pressure loss.

How to choose the installation connection method

The selection of the installation and connection method of the hydraulic cylinder should be selected according to the load characteristics and the form of movement, so that the load on the hydraulic cylinder is not loaded in the radial direction along the direction of action.
1. Flange installation provides high-strength centerline support, but has higher requirements for alignment.Rod end flanges or rodless flanges can be used to install the cylinder. Rod end flanges are more suitable for tensile loads.Long cylinders installed horizontally may require additional supports at the free end to prevent sagging;

2. The centerline lug is along the plane of the piston rod centerline.This installation method makes the installation bolt only subjected to simple stretching or shearing, without compound force.Accurate alignment is required, but it is firm after accurate alignment;

3. The trunnion is installed so that the cylinder can drive the load that moves in a curve.The trunnion is usually arranged in the plane of the centerline of the piston rod and only bears shear loads.Since it is an articulated installation, it helps to compensate for misalignment;

4. The integral earrings for earrings are part of the bottom cover of the cylinder.Since the fulcrum is outside the cylinder, the lever arm of this type of installation is longer;

5. The extension rod installation also provides the center line support like the flange installation, but the cylinder degree is low;

6. The tripod is installed because the tripod is lower than the center line of the piston rod, so that the cylinder bears the tipping moment.The stress value is higher than the centerline lug installation and the rigidity is lower.The stand-mounted type can allow slightly greater misalignment.Often keys or pins are used to bear the shear load, so that the mounting bolts are only subject to tension.

Scientific knowledge

Working principle of hydraulic cylinder XNUMX. The working principle of hydraulic transmission
The principle of hydraulic transmission: oil is used as the working medium, and power is transmitted through the pressure inside the oil.
1. Power part-converts the mechanical energy of the prime mover into the pressure energy (potential energy) of the oil.For example: various hydraulic pumps.
2. Execution part-convert the oil pressure energy input by the hydraulic pump into mechanical energy that drives the working mechanism.For example: various hydraulic cylinders, hydraulic motors.
3. Control part-used to control and adjust the pressure, flow and flow direction of the oil.For example: various pressure control valves, flow control valves.
4. Auxiliary part-connect the first three parts together to form a system, which plays the role of oil storage, filtration, measurement and sealing.For example: soft and hard pipelines, joints, fuel tanks, oil filters, accumulators, seals and display instruments, etc.

Second, the working principle of hydraulic cylinder
First understand the 5 most basic components:
1. Cylinder tube and cylinder head
2. Piston and piston rod
3. Sealing device
4. Buffering device
5. Exhaust device
The working principle of each type of cylinder is similar. Take a manual jack as an example. Its work is originally (the jack is actually the simplest oil cylinder). The hydraulic oil enters through a single valve through a manual booster (hydraulic manual pump). The hydraulic oil cylinder, at this time, the hydraulic oil entering the cylinder cannot be reversed because of the single valve, forcing the cylinder rod upward, and then the work continues to make the hydraulic oil continue to enter the hydraulic cylinder, so it continues to rise, and when it is about to fall, open the hydraulic valve , So that the hydraulic oil returns to the tank.This is the simplest, other hydraulic cylinders are improved on this basis.

It is only used when the return stroke is achieved by mechanical means such as self-weight, external load or spring force. Generally, double-acting cylinders are used.

3, Hydraulic cylinder parameter selection
Cylinder inner diameter, piston rod diameter, stroke, cylinder speed, oil port diameter

4、Cylinder tube and cylinder head structure selection
Generally, tie rod type and screw type are used for general machinery and equipment, and welding type is used for heavy cylinders and high pressure large diameter cylinders of metallurgical machinery, forging machinery, etc.

5, Hydraulic cylinder installation and connection method
Including flange type, pin type, earring type, base type, ball head type, refer to YGD series tie rod hydraulic cylinder, HSG engineering hydraulic cylinder, Y-HG1 metallurgical hydraulic cylinder

6, The choice of buffering device
When the operating speed of the hydraulic cylinder reaches a certain standard after being loaded, a hydraulic cylinder with a buffer device must be selected.Or when reaching a higher speed, a reduction valve must be installed outside the hydraulic cylinder.

7, The choice of sealing device
Choose hydraulic oil and oil seal carefully.Different hydraulic oils are suitable for oil seals of different materials to ensure the service life of hydraulic cylinders.

FAQ

1. Customized cylinders usually need to communicate clearly on technical requirements between the two parties;

2. The drawings newly designed by Jinyunbo must be confirmed in writing by the customer before processing

The main parameters of hydraulic cylinder

1. Cylinder inner diameter D

It can be calculated according to the required output force F, hydraulic system set pressure p and hydraulic cylinder mechanical efficiency ηm according to the relevant formulas in Table 4-1, but in the end, the value that meets the national standard GB2348-1993 must be selected in order to select the standard Products and standard seals

2. Piston rod diameter d
The diameter of the piston rod must be large enough to withstand the load and the stress applied by the cylinder.When the piston rod is under tension, the area of ​​the piston is equal to the piston force divided by the yield limit of the piston rod and multiplied by the safety factor.However, when the piston rod is subjected to thrust, it must have sufficient longitudinal bending strength.When the longitudinal bending strength is not enough and large deflection is generated, the friction of the sliding surface causes a large bias load on the guide sleeve and the piston, causing problems such as jamming, crawling, and abnormal wear of the seal.The additional strength required to prevent longitudinal bending depends on the stroke and the fulcrum connection method
3. Itinerary S
The stroke S of the cylinder depends on the distance of the load movement.When the stroke is long, the piston rod needs to be thicker, and a stop sleeve may be installed in the cylinder to improve the ability to resist longitudinal bending
4. Cylinder speed υ
The determination of the cylinder speed υ is related to the cycle time and the stroke of the cylinder.The generally recommended speed range is 15～300mm/s.Excessive cylinder speed will shorten the life of the seal.When the speed is too low, it is easy to crawl and cannot work smoothly.
5. Oil port diameter d0
The oil port diameter d0 should be determined according to the cylinder speed and piston area.The flow rate of the oil port should not exceed 5m/s, so as not to affect the output force of the cylinder due to excessive pressure loss.

How to choose the installation connection method

The selection of the installation and connection method of the hydraulic cylinder should be selected according to the load characteristics and the form of movement, so that the load on the hydraulic cylinder is not loaded in the radial direction along the direction of action.
1. Flange installation provides high-strength centerline support, but has higher requirements for alignment.Rod end flanges or rodless flanges can be used to install the cylinder. Rod end flanges are more suitable for tensile loads.Long cylinders installed horizontally may require additional supports at the free end to prevent sagging;

2. The centerline lug is along the plane of the piston rod centerline.This installation method makes the installation bolt only subjected to simple stretching or shearing, without compound force.Accurate alignment is required, but it is firm after accurate alignment;

3. The trunnion is installed so that the cylinder can drive the load that moves in a curve.The trunnion is usually arranged in the plane of the centerline of the piston rod and only bears shear loads.Since it is an articulated installation, it helps to compensate for misalignment;

4. The integral earrings for earrings are part of the bottom cover of the cylinder.Since the fulcrum is outside the cylinder, the lever arm of this type of installation is longer;

5. The extension rod installation also provides the center line support like the flange installation, but the cylinder degree is low;

6. The tripod is installed because the tripod is lower than the center line of the piston rod, so that the cylinder bears the tipping moment.The stress value is higher than the centerline lug installation and the rigidity is lower.The stand-mounted type can allow slightly greater misalignment.Often keys or pins are used to bear the shear load, so that the mounting bolts are only subject to tension.