Mechanism

Equations

Motion

Inertia & Torque

GEARING

 

 

 

 

 

 

 

 

REDUCER

 

 

 

 

 

Jr = Inertia of reducer reflected to input.

 

 

 

TIMING BELT

 

 

 

 

 

 

 

 

 

RACK-PINION

 

 

 

 

 

 

 

 

 

CONVEYOR

 

 

 

 

 

 

 

 

 

LEADSCREW

 

 

 

 

 

 

 

 

 

 

SYMBOLS & DEFINITIONS

 

Symbol

Definition

Metric Unit

EE Unit

CG

CP1,2…n

Circumference of Gear

Circumference of Pulleys 1, 2…n

m or cm

in or ft

D

DG

DPL

DPM

DP1,2…n

Diameter

Diameter of Gear

Diameter of Load Side Pulleys

Diameter of Motor Side Pulleys

Diameter of Pulleys 1, 2…n

m or com

in or ft

e

Efficiency of Mechanism

%

%

F

Ffr

Fg

FP

Forces

Forces due to Friction

Forces due to Gravity

Push or Pull Forces

N

lb

a or d

α

g

Linear Accel/Decel Rate

Angular Acceleration Rate

Gravity Accel Constant

m-sec2

rad-sec2

9.81 m-sec2

in-sec2

rad-sec2

386 in-sec2

J

JBM

JC

JG

JL

JLM

JM

JPL

JPM

JPLM

JP:1,2,n

Jr

JTotal

JS

Mass Moment of Inertia for…

…Belt Reflected to Motor

…Coupling

…Gear

…Load

…Load Reflected to Motor

…Motor

…Load Side Pulley

…Motor Side Pulley

…Load Side Pulley Reflected to Motor

…Pulley or Sprocket 1, 2,…n

…Reducer or Gearbox

…Total of all Inertias

Leadscrew

kg-m2

or

g-cm2

etc.

lb-in2

or

oz-in2

or

lb-in-sec2

or

oz-in-sec2

etc.

Nr

Nt

Number Ratio of Reducer

Number of Teeth on Gear, Pulley, etc.

none

none

none

none

PG

PS

Pitch of Gear, Sprocket or Pulley

Pitch of Leadscrew

teeth/m

rev/m

teeth/in

rev/in

t

ta,c or d

tm

tTotal

th

Time…

…for Accel, Constant Speed, or Decel

…for Move

…for Total Cycle

…for Hold Time

sec

sec

sec

sec

sec

sec

sec

sec

sec

sec

T

Ta,c or d

TCL

TCM

TH

TL

TP

TRMS

TTotal

Torque…

…During Accel, Constant, or Decel

…Constant at Load

…Constant Reflected to Motor

…Holding (while motor stopped)

…at Load (not yet reflected to motor)

…due to Preload on Screw, Nut, etc.

…RMS (Average) Over Entire Cycle

…Total From All Forces

Nm

in-lb

or

in-oz

VL

ω0

ωM

ωmax

Linear Velocity of Load

Initial Angular/Rotational Velocity

Angular/Rotational Velocity of Motor

Maximum Angular/Rotational Velocity

m/sec

rad/sec

in/sec

rps

or

rpm

WL

WB

WT

Weight of Load

Weight of Belt (or chain or cable)

Weight of Table (or rack & moving parts)

N

or

kg

lb

XL

Distance X Traveled by Load

m or cm

in or ft

Θ

Θa,c, or d

θL

θM

θTotal

Rotation…

…During Accel, Constant or Decel

…of Load

…of Motor

Total Rotation of Motor During Move

rad

rev

П

“PI” = 3.141592654

Rotational Unit Conversion (rad/rev)

none

rad/rev

none

rad/rev

µ

Coefficient of Friction

none

none

γ

Load Angle from Horizontal

degrees

degrees

Excerpt from:
A Comprehensible Guide To Servo Motor Sizing

by Wilfred Voss
Published by Copperhill Technologies Corporation, 2006.

Source: http://www.visualsizer.com