Both Screw jack and servo electric cylinder can realize the mechanical movement into linear or straight push/pull movements. They are ideal for all types of applications where tilting, lifting, pulling or pushing with pounds of force are required.

In comparison, due to the servo motor and servo electric cylinder screw jack combination makes the servo electric cylinder of thrust, speed and position control is more precise and therefore is widely used in modern digital and network technology, and other fields, which can realize programmed control, so the cost is higher.

Screw stability verification: known load 100KN, stroke 500mm, speed 60mm/min, no guide rail, usage coefficient 1.5, low operating frequency, calculated model For (Heavy Duty Electric Linear Actuator model SCA200-V1-500-FL-P2):

lifting Screw specification Tr80*12

1. Known conditions

Load F=100KN=100,000N

Stroke S=500mm

Speed v=60mm/min

Usage coefficient K=1.5

Screw specification Tr80*12 (diameter 80mm, pitch 12mm)

2. Analysis of screw force

The screw mainly bears the axial load, so we need to calculate the stress of the screw under the axial load.

• Screw diameter d=80mm=0.08m

•Screw cross-sectional area A=π (2d)2= π(20.08)2=0.005027㎡

•Axial load Fax=K*F=1.5×100,00N=150,000N

3. Calculation of screw stress

Screw stress o =AFax=0.00502715000=2983866.67Pa

4. Check the stability of the screw

For the stability of the screw, we mainly pay attention to whether it will flex. Since the screw is usually installed on the fixed bracket and its length is relatively short (500mm), the possibility of buckling is relatively small. However, in order to evaluate more accurately, we can use Euler's formula to estimate the critical bending load of the screw.

1. Screw length=500mm=0.5m

2. The elastic modulus of the screw material E (set to steel, E≈210GPa=210×109Pa)

3. Screw moment of inertia I=π 64d4= π64×(0.08)4=2.01062×10-7m4

Eular critical load Fcr can be calculated by the following formula:

Fcr=12 π2EI=(0.5)2π 2×210×109×2.01062×10-7=2,649,444.44N

Because Fax=150,000N＜Fcr=2,649, 444.44N, the screw is stable under axial load.

5. Summary
After calculation, it is confirmed that the screw (specification is Tr80*12) equipped with the linear actuator model SCA200-V1-500-FL-P2 is at a load of 100KN, stroke of 500mm, speed of 60mm/min, and a coefficient of use of 1.5 And the linear actuator is stable under the condition of low working frequency.

The load capacity of servo electric cylinders cannot be very high mainly due to the following reasons:

1. Servo motor power limitations: Servo electric cylinders are driven by servo motors, which have limited power. When the load is too large, the motor may not be able to provide sufficient torque to move the load, potentially resulting in motor overload or even burnout.

2. Transmission system limitations: Servo electric cylinders typically use mechanical transmission components (such as gears or ball screws) to transfer motion from the motor to the load. Excessive load can put too much stress on these components, leading to wear, damage, or failure.

3. Control system responsiveness: Servo control systems regulate motor operation by adjusting current and voltage. When the load is too heavy, the system may not be able to control the motor precisely, leading to positioning errors, system shutdowns, or overload protection activation.

4. Efficiency issues: High loads can reduce the operational efficiency of the electric cylinder, causing increased heat generation. Excessive load may also affect the effectiveness of the cooling system, raising the system temperature and shortening the lifespan of the electric cylinder.

5. Decreased precision and stability: Servo electric cylinders are typically designed to deliver high-precision motion within a specified load range. Overloading can reduce accuracy and compromise system stability, possibly causing vibrations or abnormal noises.

Therefore, when selecting a servo electric cylinder, it is essential to choose a model that matches the specific application requirements. Ensuring the load remains within the design limits of the cylinder is critical to avoid overload and ensure reliable operation.