Page 360 - MiSUMi 2025

Economy series Selection Procedure and Technical Calculation
Lead Screws

QLead Screw Technical Calculations
Calculate Contact Pressure P and Sliding Velocity V based on conditions of use to
check that no abnormal wear will occur. PV Value Graph
Calculate cross point based on the calculated P and V values in PV Graph. 1Steel (Lubrication) - Brass
When the cross point is located inside the line 1 or 2 in PV Value Graph, it can be 10 2Steel (No Lubrication) - Plastic
stated that no abnormal wear will occur. 8
6
Lead Screw Nut Selection Procedure 5 4 1 2
Determine conditions of use Axial Load, Speed 3 2

Temporarily select the Lead Screw Nut part number Lead Screw Nut Material Contact Pressure P(N/mm 2 ) 0.8 1
0.6
0.5
3 NG 0.4 3
0.3
0.2
Calculate 1 Contact Pressure P and 2 Sliding Speed V. 0.5 0.8 1 2 3 4 5 6 7 8 10 20 30 4050 80 100
Ball Screws / Lead Screws in PV Graph Use This Result For Selecting Motors, etc. Sliding Speed V (m/min) Lead Screws Ball Screws /
Confirm that the cross point is located inside the lines
Calculate 3 Screw Efficiency η
and 4 Load Torque T
Calculation Example
Rolled Ball Screws 1Contact Pressure P (N/mm ) In case of using C-MTSRW16 shaft, pitch 3 and C-MTSFRC16 brass Screws Rolled Ball
2
FS
×α
P=
flanged nut when the axial load is 300N as rotational speed at 500min -1 .
FO
Fs: Axial Load (N)
Fs
300
The thrust when the contact pressure acting on the screw shaft and
P= ×@= ×9.8=0.52(N/mm 2 )
P.03-009 Fo : Allowable Dynamic Thrust (N) ⇒Nuts for Lead Screw Specifications 1Contact Pressure P (N/mm 2 ) P.03-009
5670
Fo
nuts is 9.8 (N/mm )
2
Precision Ball Screws 2Sliding Speed V (m/min) 2Sliding Speed V (m/min) Screws Precision Ball
α: 9.8 (Brass), 0.98 (Resin)
π·d2·n
π×14.5×500
V= ×10 -3 = ×10 -3 =22.8(m/min)
cos(3°46')
cos(d)
cos(d)
cross point V=22.8(m/min) when P=0.52(N/mm 2 ) is located inside the line
P.03-027 V= π·d2·n ×10 -3 ⇒Nuts for Lead Screw Specifications When the PV Graph is viewed based on the calculated P and V values, the P.03-027
d2: Screw Shaft Effective Dia.
1 on the PV Graph, thus it can be stated that no abnormal wear will occur.
Ball Screw Supports / Motor Brackets n : Screw Shaft Revolution Frequency per Minute (min ) Required Torque when using C-MTSRW16 shaft , pitch 3, and Motor Brackets Ball Screw Supports /
d : Screw Shaft Lead Angle (Degree) ⇒Nuts for Lead Screw Specifications
-1
Calculation Example
3Screw Efficiency η
1-μtan(d)
3Screw Efficiency η
P.03-047 η = 1+μ/tan(d) C-MTSFRC16 brass (flanged nut.) P.03-047
1-0.21×tan(3°46')
1-μtan(d)
η = = =0.24
μ: Dynamic Friction Coefficient
Lead Screws QDynamic Friction Coefficient Reference Value Also, in a case of calculating for the Load Torque T (N·cm) when the Lead Screws
1+μ/tan(d)
1+0.21/tan(3°46')
d: Screw Shaft Lead Angle (Degree)
axial load is 300N.
FS·R
300×0.3
Nut
Coefficient μ
P.03-058 Thread Shaft Brass Dynamic Friction 4Load Torque T (N·cm) P.03-058
T= = =59.7(N·cm)
2π· η
2π×0.24
Steel
Lead Screw Nuts (Non Lubrication) Polyacetal / PPS Resin 0.13 Nuts Lead Screw
0.21
(Lubrication)
Steel
with Sliding Property
P.03-077 4Load Torque T (N·cm) P.03-077
Lead Screw Supports T= 2π· η Supports Lead Screw
FS·R
Fs: Axial Load
R : Lead (cm)
P.03-079 η : Screw Efficiency P.03-079
Lead Screw Stop Plates / Position Indicators Ed,d2: refer to P.04-061 Position Indicators Lead Screw Stop Plates /
E POM, PPS Nuts is MISUMI's standard Prodcuts which are
not posted to this Catalog.
P.03-081 P.03-081
03-063 03-064