yilmaz redÜktÖr vr serisi

YILMAZ REDÜKTÖR

Gearbox Selection

Parameters

R & D Department Murat Cem Ünal 22.06.2011

This is a graph of the magnitude of a cyclic stress against the logarithmic scale of cycles to failure.

The curve depends on material fatigue properties

Number of load cycle

Miner

Haibach Corten|Dolan

Endurance limit

Torque values has to be obtained from test results or simulations

Can be used to determine required service factor

Time

Teq

…

t

Factor for pitting by case carburized and through hardened materials

Dt1 Dt2 Dtn

T1

T2

Tn - 2

Tn - 1

Tn

ISO 6336 takes fatigue of tooth root and tooth flank into account

Pitting calculations are based on Hertzian contact stress

Both calculations respect the effect of tangential force

Bearing

Pitting Fatigue of tooth base

Speed [rpm]

Better fatigue strength of tooth base

Hardening of tooth root area

Optimum addendum

Optimized tool

Better foot rounding

Less pitting

Better oil

Optimum profile shift

Better roughness of tooth shoulder

Standard Profile Modified Profile

Factor of safety for critical section of shaft

Determination of critical section of shaft

Calculation of tension at the critical section

Material properties

Part specifications

Standard to calculate bearing life time

Equivalent radial and overhung load for bearing calculations

Life time calculation

Factors

Equivalent Load

Radial Load Axial Load

Equivalent load

Load rating

Bearing life time at which ninety percent of the bearings will still be operating

Life-equation exponent

Working Conditions

• Under uniform load & 8 hours per day

• Life time of product

•Ambient temperature

•Dust at working place

•Humidity …

Standards

•ISO 281

•ISO 6336:2006 (new), DIN 3990

•DIN 743

Safety

•Bearing Life

•Gear Safety

•Shaft Safety

•Stress analysis of housing

Nominal torque of gearbox

•Minimum torque of all calculations

Values to Customers

•Transmission ratio

•Output torque …

Determining nature of load

External moments of inertia reduced on motor shaft

Transmission ratio

Moment of inertia of the motor

Nature of Load

U Uniform load Fi < 0.25

M Moderate load 0.25 < Fi < 3

H Heavy shock load 3 < Fi < 10

Choosing factor for nature of load

For Fi > 10 contact with us

With experimental measurements or simulations

Time

Teq

Basic measurement influences like:

Sampling time

White noise

Sensitivity of sensor

Last but not least method to obtain service factor is:

Determining the service factor based on experiences depending on various sectors!

Determining the service factor from calculations or measurement results are complicated and not practical .

Service factor is a safety coefficient, which takes different running conditions and peak loads into account

fs = 1 means that you have:

Uniform loads, 20 ̊̊C ambient temperature, usual start stop cycles per hour and 8 hours working per day

- 10 cycles for P series - 50 cycles for all other series

Driving machine factor takes account the unbalanced working effects of combustion engines

Driving machine factor

Electric and hydraulic motors 1

Combustion engines with 4 cylinders or more 1.25

Combustion engines from 1 until 3 cylinders 1.5

Maximum torque of gearbox is torque, which can only be taken by static load. It should never be exceeded during working.

Peak torque factor takes the amplitude of to gearbox applied torque

Peak torque factor

Load peaks per hour

1-5 6-30 31-100 100<

Steady direction of load 2 1.5 1.4 1.2

Alternating direction of load 1.4 1.1 0.9 0.8

Nominal torque Peak torque of machine

Peak torque factor

Helical Gear Bevel gear Worm gear

Efficiency of one stage

98 - 99 % 97 – 98% 50 – 90 %

Helical Gear Bevel gear Worm gear

Max. transmission ratio of one stage

7 5 100

Static irreversibility:

For static irreversibility by driving from worm wheel, it should be:

Static irreversibility can not be assured by driving from worm

Dynamic irreversibility:

Static irreversibility can be overridden with dynamic load

On the catalogues given efficiencies can be used for dynamic irreversibility, static irreversibility can be calculated with angle values on the catalogues

Worm wheel

Worm

Static efficiency of worm gear

2α

Coefficient of static friction

Dynamic efficiency of worm gear

Transmission ratio i of spur gear

Transmission ratio of worm gear

Transmission ratio of planet gear while input sun gear and output carrier

Transmission ratio

Output speed

Input speed Output diameter

Input diameter

d1

d2

Transmission ratio of several stages:

Number of teeth of input gear

Transferred heat energy Efficiency of gearbox

On catalogues given values for thermal power is motor power, which can be chosen without extra cooling equipment.

Planetary gear units without external cooling can be selected if

Required power

Cooling factor

Factor for altitude Lubrication factor

Planetary gear units with heat exchanger can be selected if

Required power

Cooling factor Factor for altitude

Lubrication factor

On catalogues given values for thermal power is motor power, which can be chosen with a certain heat exchanger.

Cooling factor

Lubrication factor

Factor for altitude

Cooling Factor t1

Operation cycle per hour (ED) in %

100 80 60 40 20

… … … … …

Lubrication Factor t4

Mounting Position Dip Lubrication Expansion tank …

M1 … … …

… … … …

Wind velocity factor …

Factor for Altitude

Cooling system

Altitude above MSL

<1000m <2000m <3000m <4000m <5000m

… … … … …

Selection factors

Radial forces negligible

Overhung load

Output torque

D

Number of teeth

Low speed, low load at least 13 teeth

Moderate speed (up to 6 m/s) at least 17 teeth

Moderate load, up to 15 m/s at least 21 teeth

High speeds, high load at least 30 teeth

13 21 30

L

L/2

u

We provide t, y and L values in the catalogue

y

Fe Fqe

Representative of real force

Staring time of electric motor depends on moment of inertia

To shorten the starting time motor current should be higher

In some cases this brings motor failure because of heat

Therefore bigger motor has to be used

But this time it brings more peak torques to gearbox

As prevention a higher service factor has to be chosen or a hydraulic coupling , so more powerful motor can be used

M

A: Starting torque

M

S: Pull-up torque

M

K: Pull -out torque

M

N: Motor rated torque

ML

: Load torque

3-Phase asynchrony motor

M1

M6

M2

M3

M4

M5

M1

M6

M2

M3

M4

M5

Mounting position has to be mentioned with order

Oil quantity and the place of vent plug depends on mounting position

Poz.1 (Position 1 )

Poz.2 (Position 2 )

Poz.3 (Position 3 )

Poz.4 (Position 4 )

Poz.1 (Position 1 )

Poz.2 (Position 2 )

Poz.3 (Position 3 )

Poz.4 (Position 4 )

Poz.1 (Position 1 )

Poz.2 (Position 2 )

Poz.3 (Position 3 )

Poz.4 (Position 4 )

Nearest state to vertical axis (a) is Poz.1

Position is according to viewing behind motor.

a

Symbol Meaning

Drain plug

Filling plug

Vent plug

Oil Level

■

●

■

●

●

●

■

■

Oil Type Usage Temperature at Dip Lubrication

Usage Temperature at Forced Lubrication

ISO Viscosity

Min

era

l Oil

0 - +100 ̊C - ISO VG 680

0 - +100 ̊C - ISO VG 460

0 - +100 ̊C +15 - +100 ̊C ISO VG 320

0 - +100 ̊C +10 - +100 ̊C ISO VG 220

0 - +100 ̊C +5 - +100 ̊C ISO VG 150

0 - +100 ̊C +3 - +100 ̊C ISO VG 100

Syn

the

tic

Oil

-20 - +140 ̊C - ISO VG 680

-20 - +140 ̊C - ISO VG 460

-20 - +140 ̊C +5 - +140 ̊C ISO VG 320

-20 - +140 ̊C 0 - +140 ̊C ISO VG 220

-20 - +140 ̊C -5 - +140 ̊C ISO VG 150

-20 - +140 ̊C -8 - +140 ̊C ISO VG 100

Mineral Grease

-20 - +120 ̊C - -

Synthetic Grease

-30 - +100 ̊C - -

- Do not mix mineral oil to synthetic oil - Depending on mounting position oil quantities varies - Some gears splashes lubrication fluid upper parts of gearbox - Oil change for mineral oil 10000 operation hours, for synthetic oil 20000 operation hours (life time) no oil change required - Gearboxes, which haven’t got any expansion space for the oil, should be used with expansion tank

2 RS Bearing

Nominal power given depending on input speed

Once speed is decided, gearbox candidate can be selected according to motor power

Efficiency of gearbox is directly given if it is a low efficiency product (E) or has an importance (P,R)

Service factor has to be calculated

Thermal power is given if it is a low efficiency product (E) or power dense product (H, B, P, R, Y)

Gearbox candidate selection according to output torque and transmission ratio

Efficiency of gearbox has to be calculated

Service factor of gearbox is directly given

If the termal power is not shown on the performance tables, the service factor is given with consideration of thermal power (EV Series). High efficient gearboxes performance tables does not have thermal power because their thermal power is higher then their nominal power on normal condition (M, D, K).

AC Motors DC Motors

1 Phase Asynchrony Motors

Synchronous Motor 3 Phase

Asynchrony Motors

Self Excited Separately Excited

Shunt Wound

Series Wound Compound Wound

Body material:

Aluminum for small motor sizes; Cast iron for bigger motor sizes

Power factor cos(ρ):

Increases with increasing of nominal motor power

Decreases with decreasing motor load

Nominal Power:

Output power of motor running on label frequency and voltage under full load

Number of pole and speed (50 Hz)

2 poles ~2800 rpm

4 poles ~ 1400 rpm

6 poles ~ 900 rpm

8 poles ~ 750 rpm

Efficiency Classes Calculating

Efficiency Values of Motors with 4 Poles

IE1 EFF2 Standard Efficiency

A=0.5234 B=5.0499 C=17.4180 D=74.3171

IE2 EFF1 High Efficiency

A=0.0278 B=1.9247

C=10.4395 D=80.9761

IE3 - Premium Efficiency

A=0.0773 B=1.8951 C=9.2984

D=83.7025

IE4 - Super Premium Efficiency -

Nominal Efficiency Nominal Load

After 01-01-2015 only IE3 and IE2 with frequency inverter

Since 16-06-2011 only IE2

Direct Motor Connection B5 Flange B14 Flange

With direct motor connection minimum length of geared motor

With flange easy change of motor

B14 flange diameter on motor side is smaller then B5 flange diameter

Approximated Brake Selection

Thermal Capacity of Brake

Adjustment of the air gap:

In order to obtain the same performance from the brake the air-gap of the brake must be re-adjust after a limited time of operation

Nominal motor power

Nominal brake torque

Maximum motor speed

Safety coefficient > 2

Total inertia reduced to the motor shaft

Static load torque

Heat dissipation energy

Static load torque stimulates the rotation of motor

Static load torque opposes the rotation of motor

Static load torque opposes or stimulates rotation of motor

1

2

3

When working place is humid,

Or manufacturing process needs a cleanroom without oil vapor

Or the gearbox has to be filled fully with oil

Total volume of oil

Volume of expansion in operation

Difference between operation and ambient temperature Volume of expansion tank

Axial load while working Inner diameter of coupling

Torque, which has to be transferred

Torque, which has to be look up from tables