FORMULAS SPUR GEARS T ech nial S t o h lh lh r rh rh rh driven driver driver lh lh l h rh r rh left...

Telephone+44(0)1246268080 Fax +44(0)1246260003Unit 14, Foxwood Ind. Park, Foxwood Rd. Chesterfield, Derbyshire S41 9RN

27. 48

MODULE IMPERIAL

Corrected PCD = (No. of Teeth + 1) x MOD[(No. of Teeth + 1) / DP]

Corrected ØD = (No. of Teeth + 3) x MOD[(No. of Teeth + 3) / DP]

Our SPUR GEARS are made to give 0.07-0.3*Approx. backlash at standard centres. Housingcentres should be nominal +0.00 +0.05mm.

PCD (A) + PCD (B)=

2 * Depends on pitch

CORRECTED TEETH FOR 8 - 17 TEETHON REQUEST OR WHERE LISTED Whole depth = Addendum + Dedendum

FROM NOMINALCENTRES mm

INCREASE IN BACKLASH mm

Tooth thicknessDedendum

AddendumWhole depth

PCD

A

PCD

B

Outside Diameter

CentredistanceNominal

+0.00+0.05

CP

TO FIND:-

PCD

ØD

DP

MODULE

No. of TEETH

CP

ADDENDUM

DEDENDUM

= No. of TEETH x MOD (mm)

= (No. of TEETH + 2) x MOD (mm)

25.4=

MODULECP

= (mm)π

= PCD ÷ MODULE (mm)= MODULE x π (mm)

= MODULE (mm)

= 1.4 x MOD = 1.25 x MOD(0.25-1 MOD) (1.25-8 MOD)

No. of TEETH= (ins)

DPNo. of TEETH + 2

= (ins)DP

π=

CP”25.4

=DP

= PCD” x DPπ

= (ins)DP1

= (ins)DP1.4 (100-24 DP) 1.25 (20-6 DP)

= =DP DP

Root clearance

0.0050.0100.0150.0200.0250.0300.0350.0400.0450.050

0.00370.00740.01110.01480.01850.02210.02590.02950.03280.0370

FORMULAS SPUR GEARS Technical Section

LH LH

LH LH

RH

RH RH

RH

DRIVEN

DRIVER

DRIVER

LH LH

LH

RH

RH

RH

LEFT hand runs with RIGHT hand.

TO FIND:- MODULE IMPERIAL

P.C.D.

ØD

DP (NORMAL)

MODULE

No. of TEETH

CP (NORMAL)

ADDENDUM

Lead

No. of TEETH = (ins)

DP x COS. HELIX )<PCD. + 2

=DP

π=

CP25.4

=DP

= (DP x COS. )<°) x PCD

π= (ins)

DP1

= (ins)DP

No. of TEETH x MOD= (mm)

COS. HELIX )<= PCD + (2 x MOD) (mm)

25.4=

MODULECP

= (mm)π

PCD x COS. )<°= (mm)

MODULE

= MODULE x π (mm)

= MODULE

PCD x π=

TAN )<

Made to give 0.07-0.3mm* approx. backlash at standard centres. Housing centres should benominal +0.00 - +0.05mm.

* dependent on pitch

General Direction of Force

LEFT hand runs with LEFT hand.RIGHT hand runs with RIGHT hand.

CROSSED AXIS

PARALLEL AXIS

RHLH

DRIVEN

DRIVER

DRIVEN

DRIVER

DRIVEN

DRIVER

DRIVEN

27. 49Telephone+44(0)1246268080 Fax +44(0)1246260003Unit 14, Foxwood Ind. Park, Foxwood Rd. Chesterfield, Derbyshire S41 9RN

Technical SectionFORMULAS HELICAL GEARS

Where HELIX )< = HELIX Angle

SPUR GEARS, BSI 436 : 1940

*for other helix anglesmultiply Z by 0.75 sec2 α

*for other helix anglesmultiply Y by 1.33 cos2 α

Cos = Cosine Sec = Secant

1.33 Cos2 17°45’ = 1.2060.75 Sec2 17°45’ = 0.862

ALLOWABLE TANGENTIAL LOAD OF 30° HELIX ANGLE, 20° P.A.

WEAR

Xc Z* Sc Flbs.

K

STRENGTH

Xb Y* Sb Flbs.

DP

Xb = Speed factor for strength

Xc = Speed factor for wear

Y = Strength factor

Z = Zone factor

Sc* = Material rating (surface stress)

Sb* = Material rating (bending stress)

K = Pitch factor DP 0.8 power

F = Face width (inches)

DP = 25.4MOD

ALLOWABLE TANGENTIAL LOAD, 20° P.A.

WEAR

Xc Z Sc Flbs.

K

STRENGTH

Xb Y Sb Flbs.

DP

1N = 0.2248 lbs

Allowable tangential teeth load lbs = Torque lbs ins x 2pcd”

The lowest of the four values for pinion and wheel gives the gearrating. The normal rating for gears is based on 12 hours/day.

Torque lbs ins x .113 = Torque Nm1kg

1 lb = 1N x .2248 =2.20462

Torque Nm= Torque lbs Ins

.113

Xb = Speed Factor for Strength

Xc = Speed Factor for Wear

Y = Strength Factor

Z = Zone Factor

Sc* = Material Rating (surface stress)

Sb* = Material Rating (bending stress)

K = Pitch Factor DP 0.8 Power

F = Face Width (inches)

α = Helix Angle

DP = 25.4MOD

LOAD CALCULATIONS SPUR & HELICAL

HELICAL GEARS, BSI 436 : 1940

Technical Section

* Please refer to Material Strength page for values.

27. 50Unit 14, Foxwood Ind. Park, Foxwood Rd. Chesterfield, Derbyshire S41 9RN

Telephone+44(0)1246268080 Fax +44(0)1246260003


Rpm 1 2 4 6 8 12 18 24.5136

103060

100200400500600800

100020003000400050007000

10000

2.602.141.801.571.431.181.02

0.9350.8250.7300.7000.6800.6350.6100.5200.4500.4150.3800.3400.305

2.101.801.441.251.130.920.82

0.7350.6500.5800.5500.5300.5000.4800.4150.3550.3250.3050.2700.240

1.651.441.140.970.900.730.64

0.5850.5200.4600.4400.4250.4000.3800.3250.2800.2600.2400.2150.190

1.451.251.0

0.870.790.640.57

0.5150.4600.4000.3800.3700.3500.3350.2900.2500.2250.2100.1900.165

1.311.150.900.790.720.580.52

0.4700.4150.3600.3500.3400.3200.3050.2600.2250.2070.1900.1700.152

1.161.000.780.680.630.510.45

0.4100.3600.3200.3050.2900.2700.2600.2200.1950.1800.1650.1500.130

1.000.860.670.600.540.430.39

0.3500.3100.2700.2600.2500.2400.2300.2000.1700.1550.1450.1300.115

0.900.780.620.540.480.400.35

0.3200.2800.2500.2400.2300.2200.2100.1800.1550.1450.1320.1180.105

SPEED FACTORS SPUR & HELICALXc FOR WEAR

Xb FOR STRENGTH

RUNNING TIME (hours per day)

Rpm 1 3 6 12 24.614

10305080

100200400500600800

100020003000400050007000

10000

1.061.000.900.800.700.650.62

0.6000.5250.4350.4200.4150.4100.3850.3250.2850.2600.2400.2150.192

0.90.860.760.690.610.560.53

0.5100.4250.4000.3800.3700.3450.3300.2850.2450.2250.2080.1850.165

0.820.770.690.630.550.510.48

0.4300.4050.3600.3450.3300.3100.2950.2550.2200.2000.1850.1650.148

0.730.700.630.570.480.460.43

0.4100.3600.3200.3100.3000.2850.2700.2300.2000.1820.1680.1500.135

0.670.640.570.520.450.420.39

0.3750.3300.2950.2850.2750.2550.2450.2100.1800.1650.1520.1380.120



27. 52

No. ofTeeth

in Gear 400 200 150 100 80 60 50 40 30 26 20 15 12 1010121520263040506080

100150200400

Rack

1.091.401.842.483.093.504.274.955.607.008.00— ———

1.081.381.792.392.943.323.954.585.116.146.888.32———

1.081.361.752.322.853.163.794.304.815.626.347.448.32——

1.071.341.692.202.642.903.503.844.215.005.516.346.888.009.70

1.071.321.642.122.532.763.273.653.894.575.005.626.147.008.40

1.061.281.582.002.362.542.933.283.573.894.214.815.115.606.50

1.051.261.531.892.232.402.763.003.283.653.844.304.584.955.50

1.051.251.481.752.062.302.532.762.933.273.503.793.954.274.65

1.041.241.431.681.881.982.302.402.542.762.903.163.323.503.70

1.031.221.411.631.801.882.062.232.362.532.642.852.943.093.20

1.021.191.341.531.631.681.751.892.002.122.202.322.392.482.55

0.971.101.211.341.411.431.481.531.581.641.691.751.791.841.90

0.921.011.101.191.221.241.251.261.281.321.341.361.381.401.47

0.850.920.971.021.031.041.051.051.061.071.071.081.081.091.12

NUMBER OF TEETH ON PINION

No. ofTeeth

in Gear Rack 400 200 150 100 80 60 50 40 30 26 20 15 12 1010121520263040506080

100150200400

Rack

2.032.352.803.434.274.896.117.478.42

10.88—————

1.952.262.703.354.104.695.806.747.388.89

10.67————

1.882.192.613.243.904.475.486.306.837.949.26

11.30———

1.852.162.553.183.804.275.186.006.507.508.40

10.0011.20——

1.762.062.443.003.583.954.725.415.836.707.358.429.17

10.55—

1.741.992.362.903.423.764.444.945.356.156.717.508.009.11

10.92

1.641.892.252.703.143.463.984.474.765.425.886.506.887.488.50

1.581.812.162.562.963.223.704.184.394.945.365.926.206.677.34

1.501.712.012.392.742.933.343.703.934.424.675.075.335.686.00

1.451.611.832.162.442.612.923.203.383.743.944.244.374.634.91

1.401.551.742.032.292.442.722.943.123.413.603.843.964.144.36

1.291.441.611.822.022.172.382.552.662.872.973.173.253.353.44

1.181.281.431.601.731.832.002.142.222.362.432.522.682.692.81

1.091.171.291.431.541.601.721.811.871.982.052.142.192.262.36

1.001.091.181.271.381.451.521.581.641.751.781.841.881.94—

NUMBER OF TEETH ON PINION

HELICAL GEARS FOR 30° HELIX ANGLE, 20°P.A.

SPUR GEARS, 20°P.A. Z

ZFor other helix angles, multiply zone factor by 0.75 x Sec2 helix angle. NOTE 0.75 x Sec2 17° 45’ = 0.826

ZONE FACTORS SPUR & HELICAL Technical Section


HELICAL GEARS WITH 30° HELIX ANGLE, 20° P.A. AND 20° P.A. SPUR GEARSFor other helix angles, multiply zone strength by 1.33 x Cos2 helix angle. NOTE: 1.33 x Cos2 17° 45’ = 1.206

No. ofTeeth

in Gear Rack 400 200 150 100 80 60 50 40 30 26 20 15 12 1010121520263040506080

100150200400

Rack

The zone factor (Z) is a factor dependent on the totalcontact between mating teeth and the radii of curvatureof the tooth surfaces.Internal Gears - The zone factor for internal gears shall beequal to that for the same combination of external teethmultiplied by:-

R + 1 0.8 Power( )R=Ratio R — 1

The Strength Factor (Y) is a factor dependent on thenumber of teeth in contact, the cantilever strength of anindividual tooth, and the distribution of load over the faceof the tooth.Internal Gears - The strength factor for the pinion gearingwith an internal gear shall be the same as that for a pinionof the same number of teeth gearing with a rack. Thestrength factor for the internal gear shall be the same asthat of a rack gearing with a pinion having the samenumber of teeth as the actual pinion, multiplied by:-

3(1 + – ) T

where T is the number of teeth in the internal gear.Idler Gears The idler gears in which the teeth makecontact on one side with the driving gears and on theother with the driven gears, should be calculated on the

normal basis for wear, but the speed co-efficient used incalculating the load capacity for strength must be half thenormal value.Multiple Contact - If a gear makes contact on the same setof flanks with more than one other gear, the equivalentrunning time per day is to be taken as the sum of thoseapplying to the separate mating gears.

Given the variety of gear types, service requirements,environmental influences and service temperatureranges, the choice of lubricant is an important factor forthe service reliability and service life of the machineconcerned. The following are recommended, on thebasis of DIN 51 509 (Selection of Lubricants for Gears):-1. At peripheral velocities up to v = 2 m/s:High-consistency adhesive lubricants are used on largeopen gears.2. At peripheral velocities up to v = 4 m/s:Here, splash-lubrication using a soft gear-grease iscustomary into which the gear wheel dips3. At peripheral velocities up to v = 15 m/s:Here it is oil splash-lubrication which predominates4. At peripheral velocities above v = 15 m/s:In this range, oil spray lubrication is required in most cases.

.600

.658

.714

.770

.813

.838

.876

.900

.913

.928

.931

.930

.928

.924—

.585.639.697.750.790.813.854.872.883.896.897.893.889.882.869

.580

.630

.687

.738

.776

.796

.837

.858

.865

.875

.875

.870

.867

.861

.850

.579

.625

.681

.731

.768

.788

.824

.848

.856

.863

.864

.858

.855

.850

.839

.575

.618

.670

.720

.753

.772

.803

.822

.833

.839

.840

.835

.833

.828

.820

.573

.614

.664

.713

.742

.759

.788

.806

.815

.821

.822

.820

.818

.814

.808

.568

.605

.653

.698

.725

.738

.761

.776

.783

.791

.793

.780

.793

.791

.789

.566

.600

.646

.686

.699

.716

.736

.752

.758

.765

.767

.770

.771

.772

.767

.563

.597

.638

.677

.671

.677

.693

.705

.716

.728

.734

.740

.743

.747

.755

.561

.593

.631

.652

.633

.623

.642

.644

.654

.673

.683

.697

.703

.713

.728

.558

.591

.626

.642

.627

.611

.607

.620

.630

.645

.661

.676

.681

.695

.714

.554

.585

.617

.626

.614

.602

.574

.582

.590

.602

.613

.628

.638

.654

.684

.548

.573

.598

.605

.595

.582

.555

.544

.549

.562

.571

.584

.591

.607

.642

.542

.562

.580

.579

.572

.560

.535

.517

.523

.533

.541

.552

.561

.576

.606

.533

.550

.563

.562

.551

.543

.518

.490

.500

.511

.518

.533

.537

.550

.582

NO. OF TEETH ON MATING GEAR OR PINION

GEAR LUBRICATION

STRENGTH FACTORS SPUR & HELICAL

Y


27. 54

TO FIND:- PINION WHEEL

PCD

PITCH ANGLE(for 90° shaft angle)

PITCH ANGLE(for shaft angle <90°)

PITCH ANGLE(for shaft angle > 90°)

CONE DISTANCE

nd = or n x mod

DP(ins) (mm)

n = No. of teeth.-1 n

Y = tan (deg)N

-1 sin ΣY = tan

N + cos Σn

Σ = SHAFT ANGLE-1 sin (180 – Σ)

Y = tan N – cos (180 – Σ)n

DAo =

2 sin Γ

([ ][ ]

)

ND = or N x mod

DP(ins) (mm)

N = No. of teeth.

Γ = 90 – Y (deg)

Γ = Σ – Y

Γ = Σ – Y

See Pinion * see note


ØD

TANGENT OF THE LEAD ANGLE

CENTRE DISTANCE


THROAT Ø

TIP Ø

P.C.D.

REDUCTION RATIO



= No. of TEETH x MOD (mm)

No. of TEETH + 2= (inches)

DP

No. of TEETH + 3= (inches)

DP

No. of TEETH= (inches)

DP

No. of TEETH in WHEEL=

No. of STARTS in WORM

PCD (WORM) + PCD (WHEEL)CENTRE DISTANCE = 2

Our WORMS and WORMWHEELS are made to give 0.08 - 0.15mm backlash at standard centres.Housing centres should be nominal +0.00 +0.05mm.

FORMULAS - WORMS & WHEELS

(2 x MODULE) + PCDmm

MODULE x No. of STARTSPCD

PCD (Worm) + PCD (Wheel)in mm

2

2 + PCD”DP

CP” x No. of STARTSPCD x π

PCD” (Worm) + PCD” (Wheel)2

* A pitch angle (Σ) greater than 90° indicates an internal gear. Please contact Technical to determine if the gear can be cut.

FORMULAS BEVEL GEARS Technical Section


ALLOWABLE TANGENTIAL LOAD AT PITCH RADIUS

WEAR

Xc Sc Z F C - Fx lbs.

K x 1.33 1.1 x C

STRENGTH

Xb Sb Y F C - Fx lbs.

P 1.1 x C

hrs per dayApprox.

Total hours life

Wear multiply by

Strengthmultiply by

Gear torque =allowable Tangential Load x PCD”

2

Allowable Tangential Load =Gear Torque x 2

PCD

0

0.5

1

3

6

12

24

0

100

1000

5000

10000

26000

52000

3.0

2.91

2.38

1.66

1.35

1.0

0.79

2.0

1.89

1.55

1.27

1.14

1.0

0.9

(

( )

)

Based on 12 hour day.

Cone Distance C = PCD" of Gear2 x Sin Pitch Angle of Gear

Allowable tangential load at PCR = Torque lbs ins x 2PCD”

Pitch Angle of Gear = 90° – Pitch Angle of Pinion

Pitch Angle of Pinion = tan –1 No. of Teeth PinionNo. of Teeth Gear

Xc = Speed factor for wear

Z = Zone factor (see chart)

Sc* = Material rating (surface stress)

Sb* = Material rating (bending stress)

K = Pitch factor DP 0.8 power

F = Face width (inches)

Xb = Speed for strength

Y = Strength factor

C = Cone distance (inches)

P = DP

lbs

The lowest of the fourvalues for pinion and wheelgives the gear rating. Thenormal rating for gears isbased on 12 hours/day.

BEVEL GEARS, BSI 545 : 1949

LOAD CALCULATIONS BEVELS

Technical Section

* Please refer to Material Strength page for values.


27. 56

BEVEL GEARSmaximum ratio 4:1 Gleason

No. ofTeeth

in Gear 15 16 19 20 24 25 26 30 32 45 48 60 7215161920242526303245486072

1.8001.8502.0502.1002.2452.2502.2552.3502.3802.4502.5002.600

—

1.8501.9502.2352.2402.2602.2652.2652.4552.5002.6502.7002.740

—

2.0502.2352.3002.3552.6002.6002.6502.7502.7553.0003.0003.1003.150

2.1002.2402.3552.4502.7302.7402.7502.7702.7753.2003.3003.3503.400

2.2452.2602.6002.7302.8502.9002.9503.2003.2503.6003.6503.7503.800

2.2502.2652.6002.7402.9002.9003.0503.2503.3003.7503.7503.8003.950

2.2552.2652.6502.7502.9503.0503.2003.4003.4503.8003.8504.0004.100

2.3502.4552.7502.7703.2003.2503.4003.6503.7004.1004.2004.5004.700

2.3802.5002.7552.7553.2503.3003.4503.7003.7004.2004.3004.7004.850

2.4502.6503.0003.2003.6003.7503.8004.1004.2005.0005.2005.8005.950

2.5002.7003.0003.3003.6503.7503.8504.2004.3005.2005.4005.9006.100

2.6002.7403.1003.3503.7503.8004.0004.5004.7005.8005.9006.6007.000

——

3.1503.4003.8003.9504.1004.7004.8505.9506.1007.0007.700

NUMBER OF TEETH IN MATING GEAR

No. ofTeeth

in Gear 15 20 30 40 60 80152030406080

.625

.585

.570

.580

.600—

.660

.625

.620

.625

.640

.650

.670

.705

.710

.715

.720

.720

.705

.730

.765

.770

.765

.760

.710

.745

.795

.825

.830

.790

—.750.810.840.860.855

NUMBER OF TEETH IN MATING GEAR

Rpm Xc Rpm Xc Rpm Xc Rpm Xc12468

1.000.880.770.700.67

10204060

100

.635

.550

.485

.460

.425

200400600800

1000

.375

.330

.310

.285

.275

2000400060008000

10000

.230

.180

.165

.140

.125

Rpm Xc Rpm Xc Rpm Xc Rpm Xc12468

.66

.64

.62

.59

.58

10204060

100

.570

.525

.480

.460

.425

200400600800

1000

.375

.330

.310

.285

.275

2000400060008000

10000

.230

.180

.165

.140

.125

SPEED FACTORS Xb FOR STRENGTH

SPEED FACTORS Xc FOR WEAR

ZONE FACTORS Z

STRENGTH FACTORS Y

Technical Section


O/D of Worm”

PCD of Worm” )

Rubbing Speed Feet/Minute = Worm pcd” x π x RPM12

(

LOAD CALCULATIONS WORMS & WHEELS

Xc = Speed factor for wear (see chart)

0.18 = Constant value

Sc = Material rating - surface stress (see tables)

Sb = Material rating - bending stress (see tables)

efw = Effective face width of wheel

Xb = Speed factor for strength

1.8 = Constant value

M = Addendum in inches

D = Wheel PCD”

Lr = Length at root of wheel teeth in inches

Cosα = Cosine of lead angle of worm

x secant lead angle

TORQUE CAPACITY (based on 12 hour day)WEAR

0.18 Sc Xc efw D1.8 lbs. Ins.

STRENGTH

1.8Sb Xb Lr M D Cosα lbs. ins.

BSI 721 : 1937

1/6 1/4 1/2 1 2 3 4 6 8 10 18 24WearStrength

—0.50

0.380.54

0.420.56

0.470.59

0.550.64

0.620.68

0.680.72

0.780.79

0.870.87

0.940.94

1.151.15

1.241.24

Xc and Xb to be divided by factors below for different hrs/day

efw = 2 x Addendum” (Worm O/D” – Addendum”)


Note : The lowest of the fourvalues for Worm and Wheelgives the gear rating.Cosθ =

Lr = 2 x θ° x Worm O/D2

x 0.01745

Angle θ° = Cos -1 θ

efw

Lr

Technical Section


27. 58

SPEED FACTORS WORMS & WHEELS

Xb FOR STRENGTH

RPMSpeedFactor RPM

SpeedFactor RPM

SpeedFactor RPM

SpeedFactor

10

15

20

30

40

50

60

70

80

0.560

0.540

0.520

0.500

0.480

0.460

0.450

0.440

0.430

90

100

150

200

250

300

350

400

450

0.420

0.415

0.384

0.365

0.350

0.340

0.335

0.330

0.320

500

600

700

800

900

1000

1500

2000

2500

0.310

0.300

0.290

0.280

0.270

0.260

0.240

0.225

0.210

3000

3500

4000

4500

5000

6000

7000

8000

9000

0.200

0.190

0.180

0.175

0.170

0.160

0.150

0.140

0.135

Technical Section

Xc FOR WEARRPM ofWorm &Wheel 1 4 10 40 100 200 600 1000 20002500

2000

1000

800

500

200

100

40

20

10

2

.19

.21

.26

.27

.32

.42

.48

.58

.65

.71

.82

.17

.185

.24

.25

.3

.38

.46

.55

.6

.7

.8

.165

.18

.23

.24

.28

.36

.43

.51

.56

.61

.71

.145

.155

.195

.21

.245

.32

.37

.45

.50

.54

.65

.13

.140

.175

.19

.23

.28

.34

.40

.45

.48

.57

.118

.13

.16

.175

.20

.260

.31

.36

.41

.44

.54

.099

.107

.135

.15

.17

.220

.26

.31

.34

.37

.45

.090

.097

.125

.135

.155

.20

.23

.28

.32

.34

.42

.078

.085

.106

.115

.135

.17

.20

.24

.27

.29

.36

RUBBING SPEED (ft/min)


A B C D E

7,000

8,500

10,000

6,000

Phosphor BronzeSand CastPhosphor BronzeChill CastPhosphor BronzeCentrifugally Cast

Cast Iron (Gray)

A

B

—

—

—

900*

600*

800*

1000*

600*

600

800

1000

600

700

900

1100

600

1400*

1600

2000

750

Find surface stress factor Sc forwheel, under worm material

classification letterBending Stress

Factor SbPounds per

Sq. In.

WHEEL Materials

HPC ‘standard’ wheels use sand cast PB2*For ’standard’ hardened worms use 1400 Sc value for wheels

NOTE: Section E - hardened, ground and polished.HPC Standard Worms Unhardened - Sc = 1400 Sb = 17,000

Hardened - Sc = 6000 Sb= 27,000

Wheel

A B C D E

20,000

22,000

27,000

40,000

47,000

47,000

47,000

0.4% Carbon SteelNormalised0.55% Carbon SteelNormalisedLow-carbon CasehardeningSteel3.5% NickelCasehardening Steel5% Nickel Casehardening Steel3.5% Nickel ChromiumCasehardening SteelHigh Nickel-chromCasehardening Steel

1400

2000

6000

6500

7000

7000

8000

900✝

1100✝

4000✝

4000✝

4000✝

4000✝

4000✝

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

2000✝

2000✝

2000✝

2000✝

* Maximum permissible rubbing speeds, 500 feet per minute.✝ Should not be used except for hand operated gearing.

Bending StressFactor Sb

Pounds per Sq. In.

WORM Materials

Worm

BENDING AND SURFACESTRESS FACTORS WORMS & WHEELS

D

E

C

Find surface stress factor Sc forwheel, under worm material

classification letter

Technical Section


27. 60

RubbingSpeedFt. permin.

Coeffi-cients ofFriction







30405060708090

100110120130140150160170

0.0730.0700.0660.0620.0600.0580.0560.0540.0520.0510.0500.0490.0480.0470.046

180190200225250275300325350375400425450475500

0.0450.0440.0430.0410.0400.0380.0360.0350.0340.0330.0330.0320.0310.0300.030

550600650700750800850900950

100011001200130014001500

0.0280.0270.0260.0260.0250.0240.0230.0230.0220.0220.0210.0200.0190.0190.018

160017001800190020002100220023002400250026002700280029003000

0.01750.01700.01650.0165 0.01600.01600.01550.01500.01500.01500.01450.01450.01400.01400.0140

Coefficients of Friction for Worm Gearing

Excluding bearing and oil churning losses. Values are based on PB2 Wheels and casehardened and ground and polished worms lubricated by mineral oil. The efficiency maybe improved after the “running in” period. NOTE: As HPC standard worms are nothardened ground and polished lower efficiency values can be expected.

Output Torque 100INPUT TORQUE = x

Ratio Efficiency

OUTPUT TORQUE = Input Torque x Ratio x Efficiency 100

EFFICIENCY WORMS & WHEELS

TAN )<°Efficiency (%) =

TAN (θ°+ )<°)

θ° = TAN-1 f)<° = Lead Anglef = Coefficient of friction

[ ] X 100

Technical Section

FORMULAS SPUR GEARS T ech nial S t o h lh lh r rh rh rh driven driver driver lh lh l h rh r rh left...

Documents

Transcript of FORMULAS SPUR GEARS T ech nial S t o h lh lh r rh rh rh driven driver driver lh lh l h rh r rh left...