How to choose the right screw lift with the right calculation

Introduction: In the selection of screw lifts, many designers choose the tonnage according to the model. However, in practice, the screw lift cannot select the model according to the standard. Then how do you select the right model for the screw lift in practical use?

What should be the selection of the screw lift when it is used to combine two linked screw lifting platforms and four, eight, sixteen, and other lifting platforms? Our company has summarized how to select wires based on years of project experience combined with lift selection manuals. Rod lift model and how to use the formula to verify whether the screw jack model we selected in the project is correct. This solution is applicable to the trapezoidal screw lifts of the SWL, JWM, JWB, GLFSL, GLFSJ, SJ, MA, SJB series. Ball screw lift selection.

Determination of screw lift model:

1 Calculate the equivalent load of the switchboard Ws(N)

Ws = maximum load Wmax X use factor fs(N)

Use the coefficient (fs) table

2Calculate the equivalent load of a single screw lifter

W = WS / (number of linked units * linkage coefficient fd)

Coupling coefficient (fd):

Number of linkages 2 3 4 5~8

The use factor 0.95 0.9 0.85 0.8

3 tentative screw lift model:

Take full account of load, speed, stroke, efficiency, and drive source selected temporarily.

4 trip check:

The selected stroke has allowance in the use stroke, and fully considers whether the output screw has a dustproof bellows, the inertia of the screw shaft movement, various top output parts, etc.

5 screw stability check:

When the screw rod is subjected to axial compression load, check its stability. For details, refer to the stability check calculation. If the lead exceeds its critical load value, please refer to the model number before calculating.

6 input power check:

The input power required by the load is compared with the maximum input power of the inverter. If the input power exceeds the maximum input power, increase the model or reduce the spindle speed before calculating.

Load input power calculation:

Required input shaft speed n1(r/min)n1=V*I/L

Required input shaft torque M1(N*m) M1=(W*L)/(2π*i*η)+TO

Required input power P1=(T*n1)/9550

V: screw lifter screw shaft (moving nut) lifting speed mm/min L: screw pitch (m) i: reduction ratio Π: pi

W: Single screw lifter equivalent load N n: Overall efficiency of the screw lift TO: No load torque (Nm)

(L, i, n, TO refer to the basic parameter table)

7 Other check items:

(1) When the selected type is the active nut type, check the spindle speed.

(2) When there is lateral load, please add the guide.

(3) When the screw jack drives are arranged in series (ie, two or more screw jacks are arranged on the same axis), the strength of the input shaft end of each screw lift must be checked.

MA: Required input torque for screw jack A

MB: Required input torque for screw lifter B

Motor Required Torque M1=MA+MB<Acceptable Input Shaft Torque for Lead Screw Jack

8 Confirmation of the top of the output and additional components:

The dustproof bellows is selected according to the conditions of use and the amount of dust.

According to the output of the top of the connection to select the top output parts and other (such as counters, etc.).

Four sets of linked screw screw lift combination lifting platform example:

Four units are used for continuous operation. The four interlocking modes shown in the figure below are used to maintain the normal temperature in the factory. There is a little dust and there is a lateral load. The guides are set on the side of the screw lifter. The mounting state is fixed by the base. With a fixed support, the power supply is three-phase 380V/50HZ and the frequency of use is 2 times/hour x 8 hours.

1. Maximum axial load: 88 KN/4 units

2. Lifting speed: 10mm/s (600mm/min)

3. Use the stroke: 260mm

Source: Baoding Grove Machinery Manufacturing Co., Ltd.