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P R E C I S I O N G R O U N D G E A R S

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Product information updated April 2015 and subject to change. Please contact Sales for the latest prices and availability.

Spur & Helical Gears

Description Symbol Unit EquationNormal Module mn Transverse Module mt = mn / cos bAxial Module mx = mn / sin bNormal Pressure Angle an degrees = 20°Transverse Pressure Angle at degrees = tan-1 (tan an / cos b)Helix Angle b degrees = 15°Lead Angle l degrees = 90 - bNumber of Teeth zProfile Shift Coefficient x = zero for Ondrives standard gearsAddendum ha mm = 1.00 · mn (for Ondrives standard gears)Dedendum hf mm = 1.25 · mn (for Ondrives standard gears)Tooth Depth h mm = 2.25 · mn (for Ondrives standard gears)Gear Ratio u = z2 / z1Centre Distance a mm = (d1 +d2) / 2Pitch Circle Diameter d mm = z · mt = (z · mn) / cos bTip Diameter da mm = d + (2mn · x) + (2 · mn)Root Diameter dr mm = da – (2 · h)Normal Pitch pn mm = p · mnTransverse Pitch pt mm = p · mt = (p · mn) / cos bAxial Pitch px mm = p · mx = (p · mn) / sin bNormal Tooth Thickness in Pitch Circle sn mm = (pn / 2) + 2mn · x · tan anTransverse Tooth Thickness in Pitch Circle st mm = (pt / 2) + 2mt · x · tan at = sn / cos b

When working with a pair of gears the subscript 1 and 2 denotes input (drive) and output (driven) gear.Tip diameter is the theoretical diameter of the gear without tooth thickness tolerance applied. H7 Tolerance is applied.Root diameter is the theoretical diameter of the gear without tooth thickness tolerance applied. Actual root diameter will be less due to manufacturing profile shift coefficient calculated from DIN 58405/3967 tooth thickness tolerance.Root and root fillet radius is full ground. Root fillet radius shape is trochoid. Tooth thickness (sn & st) is the theoretical value. Actual tooth thickness will be less due to DIN 58405/3967 tolerance applied. The subscript e is for upper allowance values and i for lower allowance values.For two helical gears to run together one must be left hand and the other right angle helix.

da1 dr1

st

pt

ab

d1


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Spur & Helical Gears

ManufactureAll gears are form ground including root and root fillet radius resulting in no step at the start of the involute profile.Root fillet radius shape is trochoid. True circle radius and other shapes can be produced as required.

Gears can be manufactured with profile modifications. Examples include:• Tip and Root relief (Linear, Arc, Progressive, and Linear with radii transition)• Profile Crowning (Barrelling)• Pressure Angle Modification• Tip Chamfer

Gears can be manufactured with tooth trace (lead) modifications. Examples include:• End relief (Linear and Arc)• Crowning• Helix Angle Modification• End and Tip End Chamfer

Gear QualityGears are manufactured to quality grade 4 DIN 3961 for 1 module and above. Below 1 module the quality grade is 5 DIN 3961. Onboard machine and stand alone CMM measurement inspection allows testing and certification. Dual and single flank testing is available on request. Gears can be manufactured to a range of different quality grades and standards (ISO, AGMA, BS). Please contact our Technical department to discuss.

Backlash and Tooth thicknessValue stated on catalogue page is theoretical circumferential backlash per DIN 3967 for two identical gears with the same number of teeth, running at JS7 centre distance tolerance. Where DIN 58405 applies base tangent length allowances are converted to tooth thickness allowances and the formula per DIN 3967 used.

TorqueThe stated torque value is the maximum load for two identical gears running at a input speed of 500rpm, to achieve Root factor of safety SFmin = 1.4 or Flank (Hertzian) factor of safety SHmin = 1.0 (whichever is reached first) using ISO 6336-2006 method B. The following was used:

Application factor Ka = 1Required service life 12,000 hoursType of mounting for the pinion ISO 6336 Figure 13eMaterial BS 805M20 case hardening steel. ISO 6336-5 Figure 9/10 (MQ), core strength >=30HRCFatigue strength for tooth root stress σFlim= 500N/mm²Fatigue strength for Hertzian pressure σHlim= 1500N/mm²Lubrication grease: Mineral-oil base, Kinematic viscosity v40 = 120. Kinematic viscosity v100 = 12 Scuffing (integral or flash temperature) and wear is not considered. Values for 17-4PH gears are 80% of the case hardened steel gears. Other factors including shaft deflection, duty cycle and temperature will effect maximum allowable torque and service life. Wear and scuffing is dependent on lubrication. We recommend that each user compute their own values based on actual operating conditions and test in application.

Example: DIN 4 helical, 3 module, 50 teeth, 30mm face width, 15° helix.

DIN 3961: 7 6 5 4ISO 1328: 7 6 5 4AGMA 2000-A88: 10 11 12 13AGMA 2015-1-A01: A7 A6 A5 A4

Grade

Pitch total deviation: Fp µm 16.0 18.0 - Pitch single deviation: fp µm 4.0 4.6 4.0Concentricity deviation: Fr µm 11.0 14.0 15.0Pitch error: fu µm 5.5 - - Total profile deviation: Fα µm 5.0 6.5 5.3Total helix deviation: Fβ µm 6.5 6.5 4.7Double flank composite transmission error: Fi" µm 13.0 21.0 23.0Double flank tooth-to-tooth transmission error: fi" µm 5.5 7.5 7.1

Standard:Grade:

DIN4

ISO4

AGMA13


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Worms & Wheels

Description Symbol Unit EquationAxial Module mxNormal Module mn = mx · cos l Normal Pressure Angle an degrees = 20°Transverse Pressure Angle at degrees = tan-1 (tan an / cos l)Lead Angle l degrees = tan-1 ((mx · z1) / d1)Helix Angle b degrees = 90 - lNumber of Starts on Worm z1Number of Teeth on Wheel z2Profile Shift Coefficient x = zero for Ondrives standard wormsAddendum ha mm = 1.00 · mx (for Ondrives standard worms)Dedendum hf mm = 1.25 · mx (for Ondrives standard worms)Tooth Depth h mm = 2.25 · mx (for Ondrives standard worms)Gear Ratio u = z2 / z1Centre Distance a mm = (d1 +d2) / 2Reference Diameter of Worm d1 mm = (mx · z1) / tan lReference Diameter of Wheel d2 mm = mx · z2Tip Diameter of Worm da1 mm = d1 + (2 · mx)Root Diameter of Worm dr1 mm = da1 – (2 · h)Tip Diameter of Wheel da2 mm = d2 + (2 · mx)Root Diameter of Wheel dr2 mm = da2 – (2 · h)Outside Diameter of Wheel de2 mm = da2 + mxNormal Pitch pn mm = p · mnAxial Pitch px mm = p · mxNormal Tooth Thickness in Pitch Circle sn mm = sx · cos lTransverse Tooth Thickness in Pitch Circle sx mm = (px / 2)

QualityGear Quality: Worm = 6 DIN 3974, Wheel = 7 DIN 3974When working with a gear set, the subscript 1 denotes a worm and 2 a wormwheel. Tip diameter is the theoretical diameter of the gear without tooth thickness tolerance applied.For sn and sx, when x = zero, this is the theoretical tooth thickness.Actual tooth thickness will be less. The subscript e is for upper allowance values and i is for lower allowance values.

d2 dr2 da2 de2

a

X N

l

N Xd1


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Worms & Wheels

ManufactureWheels are precision hobbed. Ground worms are CBN form ground including root and root fillet radius resulting in no step at the start of the involute profile. Reference profiles DIN 867 1.25/0.20/1.00 form ZI for worms and DIN 867 1.25/0.20/1.00/0.20 for wheels.

Backlash and Tooth thicknessValue stated on catalogue page is theoretical circumferential backlash per DIN 3967 for two identical gears with the same number of teeth, running at JS7 centre distance tolerance. Where DIN 58405 applies base tangent length allowances are converted to tooth thickness allowances and the formula per DIN 3967 used.

TorqueStated value is maximum torque based on lowest figure from surface durability, tooth root strength or wear.Value is output torque T2 at wheel. Tooth root failure of teeth on wheel before teeth of worm is assumed. Worm 817M40 steel.

Other factors including worm shaft deflection, duty cycle and temperature will effect maximum allow torque and service life. Wear is dependent on lubrication. We recommend that each user compute their own values based on actual operating conditions and test in application. See BS 721-2, AGMA 6034-B92, DIN 3996 or ISO/TR 14521 standards.

Axial SectionNormal Section

pn

dr1 d1 da1

sn px sx

ha

hf

When selecting worm application factors should be applied to required torque.

T2 > T required x Ka

Application factor Ka

Working characteristicsof driving machineUniformLight ShocksModerate ShocksHeavy Shocks

Uniform1.001.101.251.50

LightShocks

1.251.351.501.75

Moderate Shocks

1.501.601.752.00

HeavyShocks

1.751.852.002.25+

Working characteristics of driven machine

Input SpeedLifeLimiting Stress N/mm2 (CA104)Limiting Stress N/mm2 (GG25)LubricationLubrication ViscosityApplication Factor

Surface Durability

15.2 4.1

Tooth Root Strength

6940

100 rpm Uniform Speed25,000 hours

Mineral OilBetween 60mm2/s and 130mm2/s at 60°C

1.00


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Worms & Wheels

EfficiencyThe following allows an approximate value for the efficiency of the gears to be found allowing required input torque and gearforces to be calculated. Efficiency is dependent on lubrication and the figures below do not include bearing, seal and other losses.

Coefficient of friction µ (Mineral Oil)

h = tan l / tan (l+ pz)pz = arctan (µ)vg = (d1 · n1) / (19098 . cos l)T1 = (T2 / u) * h

T1 = Input Torque (Nm)T2 = Output Torque (Nm)u = Ratioh = Efficiencyl = Lead Angle (degrees)m = Coefficient of Frictionpz = Angle of Frictionvg = Sliding Velocity (m/s)n1 = rpm of Wormd1 = Reference Diameter of Worm (mm)

VelocityRange(m/s)

0.0-0.91.0-1.92.0-2.93.0-3.94.0-4.95.0-5.96.0-6.97.0-7.98.0-8.99.0-9.9

10.0-10.911.0-11.912.0-12.913.0-13.914.0-14.915.0-15.916.0-16.917.0-17.918.0-18.919.0-19.920.0-20.921.0-21.922.0-22.923.0-23.924.0-24.925.0-25.926.0-26.927.0-27.928.0-28.929.0-29.9

30.0

00.15000.04380.03290.02760.02420.02190.02020.01870.01760.01690.01610.01550.01490.01460.01430.01410.01390.01370.01350.01340.01320.01310.01300.01290.01280.01270.01260.01250.01240.01230.0123

0.10.08030.04230.03220.02720.02390.02170.02000.01860.01750.01680.01600.01540.01490.01460.01430.01410.01380.01360.01340.01330.01310.01300.01290.01290.01280.01270.01260.01250.01240.0123

-

0.20.06940.04100.03160.02680.02360.02150.01990.01850.01740.01660.01590.01540.01490.01460.01430.01410.01380.01360.01340.01330.01310.01300.01290.01280.01270.01260.01250.01240.01240.0123

-

0.30.06230.03960.03090.02650.02340.02140.01970.01840.01730.01660.01590.01530.01480.01450.01420.01400.01380.01360.01340.01330.01310.01300.01290.01280.01270.01260.01250.01240.01240.0123

-

0.40.05830.03820.03040.02610.02320.02120.01960.01830.01730.01640.01590.01530.01480.01450.01420.01400.01380.01360.01340.01330.01310.01300.01290.01280.01270.01260.01250.01240.01240.0123

-

0.50.05430.03690.02970.02570.02290.02100.01940.01820.01720.01640.01580.01520.01470.01440.01420.01390.01380.01360.01340.01330.01310.01300.01290.01280.01270.01260.01250.01240.01240.0123

-

0.60.05210.03590.02930.02540.02260.02090.01930.01810.01720.01640.01570.01510.01470.01440.01420.01390.01370.01350.01340.01320.01310.01300.01290.01280.01270.01260.01250.01240.01240.0123

-

0.70.05000.03520.02890.02510.02240.02070.01920.01790.01700.01630.01560.01510.01470.01440.01420.01390.01370.01350.01340.01320.01310.01300.01290.01280.01270.01260.01250.01240.01240.0123

-

0.80.04800.03440.02860.02480.02230.02050.01900.01780.01690.01620.01560.01500.01460.01440.01410.01390.01370.01350.01340.01320.01310.01300.01290.01280.01270.01260.01250.01240.01230.0123

-

0.90.04590.03360.02800.02450.02210.02030.01890.01770.01690.01620.01560.01500.01460.01440.01410.01390.01370.01350.01340.01320.01310.01300.01290.01280.01270.01260.01250.01240.01230.0123

-

µ for Velocities 0-30m/s

Example: if Vg = 1.2 then µ = 0.0410


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Worms & Wheels

Gear Forces and Direction of Rotation

Ftm1 = 2000*(T1 / d1) = - Fxm2Ftm2 = 2000*(T2 / d2) = - Fxm1Frm1 = Ftm1*[tan 20 / (sin l + pz) ] = - Frm2

pz = arctan (m)Ftm = Tangential force (N)Fxm = Axial force (N)Frm = Radial force (N)When working with a gear set, the subscript 1 denotes a worm and 2 a wormwheel.

Ondrives worm and wheel gears are supplied right hand lead as standard.The arrows show the direction of rotation.

Ftm1 = -Fxm2

Frm1 = -Frm2

Ftm2 = -Fxm1


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Racks & Pinions

Description Symbol Unit EquationNormal Module mnTransverse Module mt = mx / cos bAxial Module mx = mx / sin b Normal Pressure Angle an degrees = 20°Transverse Pressure Angle at degrees = tan-1 (tan an / cos b)Helix Angle b degreesNumber of Teeth zProfile Shift Coefficient x = zero for Ondrives standard gearsAddendum ha mm = 1.00 · mx (for Ondrives standard gears)Dedendum hf mm = 1.25 · mx (for Ondrives standard gears)Tooth Depth h mm = 2.25 · mx (for Ondrives standard gears)Pitch Height of Rack Ho Height of Rack BReference Diameter of Mating Gear d mm = z · mt = (z · mn) / cos bCentre Distance a mm = Ho + d + x

ManufactureRacks are induction hardened and precision ground to DIN 867 tooth form. Racks can be butt jointed end to end to create longer lengths as required. Mounting gauges are available on request. UPHGR helical racks are right hand helix 19° 31' 42". Mating gears for UPSGR spur racks are RUPSG.Mating gears for UPHGR helical racks are RUPHG and must be left hand helix.

Gear Quality and Tooth thicknessRacks are manufactured to quality grade 6h23 DIN 3962/3963/3967.

BacklashValue stated on catalogue page is theoretical circumferential backlash per DIN 3967 for gear and rack running at H7 centre distance tolerance.

d

Ho Ho

a

B


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Materials

Ondrives can manufacture gears in a range of additional materials including bronzes, engineering plastics, special steels and stainless steels.Gears can be heat treated by a range of methods to improve performance.Please contact our Technical department who will be happy to discuss your specific requirements.

Material EquivalentsB.S. 970

817M40T805M20303S21316S16080M40655M13722M24

PB2CA104

Brass CZ121

B.S. 1452Cast Iron 250

Titanium Ti-6AL-4V

En24T3625858J8

3640B

ISOCu89Sn11

GZ-CuAL10NiCuZn39Pb3

EnEN-GJL-250

B.S.2TA11

DIN40NiCrMo8-4 / 34CrNiMo620NiCrMo2-2 / 20NiCrMo2

X10CrNiS189X5CrNiMo17133

C4014NiCr14

32CrMo12

DINCuSn12

CuAL10Ni-

DINDIN 1691 GG25

UNSR56400

Werkstoff1.6562, 1.6582

1.65231.43051.44361.05111.57521.7361

Werkstoff3.7165

SAE/AISI4340, 4337

8620303316

10403415, 3310, 9314

-

SAE/AISISAE 64

ASTM B150 UNC C63200UNC C38500

AMS4911/4928

Material805M20

817M40T080M40

722M24T303S21316S1617-4PHCA104

PB2Brass CZ121PEEK GF30Delrin POM

Cast Iron GG25Titanium Ti-6AL-4V

Case Hardened

Nitride HardenedCold DrawnCold DrawnCondition A

Sand Cast

Continuous CastGrade 5

Density(Kg/m3)

7,8507,8507,8507,8508,0008,0007,7807,5808,6008,4701,4901,4107,2004,420

Elongationafter

Fracture11%

5 - 13%7 - 17%

13%35 - 45%

40%10%15%5%

20%2.7%30%

-10 - 18%

TensileStrength(N/mm2)

980850 - 100510 - 600850 -1000480 - 510

5151103 750

360 - 500410156 67

145 - 195895 -1000

0.2% ProofStress

(N/mm2)785680340650

180 - 200205100430

170 - 280200

---

828 - 910


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Backlash

The backlash figure given for spur and helical gears is the theoretical backlash for two identical gears (or gear and rack) at standard centre distance to a centre distance tolerance As.It is given as circumferential backlash in mm measured on pitch circle diameter. An upper and lower value is quoted.Backlash is calculated according to DIN 3967.Ondrives can manufacture gears to a wide range of tolerances to suit customer application.Please contact our Technical department who will be happy to discuss your specific requirements.

Asn = Tooth thickness allowance which is the difference between measured gear tooth thickness and theoretical value measured in the normal section. When working with a pair of gears the subscript 1 and 2 denotes input (drive) and output (driven) gear.

For worm and wheel, 1 relates to the worm and 2 to the wormwheel. The subscript e is for upper allowance and i for lower allowance.Tsn = Tooth thickness tolerance measured in the normal section. (mm)Asne = Sn – Sne

Asni = Asne – Tsn = Sn – Sni

Circumferential Backlash jtThis is the length of arc on the pitch circle diameter through which each can be rotated whilst the other is held stationary.It is measured in the transverse section.

Units = mm & degrees

Normal Backlash jnThis is the shortest distance between the flanks of the gears when the opposite flanks are in contact.It is measured in the transverse section.For spur, helical, crossed axis helical gear


Change in Circumferential due to Centre Distance Tolerance Dja


Angular Backlash jq


d2 = Reference diameter (mm)As = Centre distance tolerance (i.e. a = 30mm Js7, As = ±0.0105mm)an = Normal pressure angle (an = 20°)b = Helix angle (b = zero for spur gears) Replace helix angle b with lead angle l for worm and wheel.1° = 60 arc minutes

360 x p x d2


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Backlash

Tooth and Centre Distance Tolerance

DIN 3967

DIN 58405

UPSG Spur GearUPHG Helical GearRUPSG Spur Rack GearUPSGR Spur RackRUPHG Helical Rack GearUPHGR Helical RackPWG WormwheelUPW, UPSW Worm

Module0.5 to 0.8

5f DIN 584055f DIN 58405

7e DIN 584056e DIN 58405

Module1.0 and above

f24 DIN 3967f24 DIN 3967f24 DIN 3967h23 DIN 3967f24 DIN 3967h23 DIN 3967e25 DIN 3967e25 DIN 3967

Centre DistanceTolerance As

JS7JS7H7H7H7H7JS8JS8

Over Including Asne Tsn Asne Tsn Asne Tsn

01050

125280

1050

125280560

-0.010-0.014-0.019-0.026-0.035

+0.012+0.020+0.025+0.030+0.040

-0.022-0.030-0.040-0.056-0.075

+0.020+0.030+0.040+0.050+0.060

0.0000.0000.0000.0000.000

+0.008+0.012+0.016+0.020+0.025

Reference Dia. d f24 e25 h23

Over Including Asne Tsn Asne Tsn

36

122550

100200

6122550

100200400

-0.012-0.014-0.016-0.018-0.020-0.022-0.024

+0.006+0.007+0.008+0.009+0.011+0.012+0.013

-0.014-0.016-0.018-0.020-0.022-0.024-0.028

+0.007+0.008+0.009+0.011+0.012+0.013+0.014

Reference Dia. d 0.5 Module 5f 0.8 Module 5f

Over Including Asne Tsn Asne Tsn

36

122550

100200

6122550

100200400

-0.030-0.035-0.040-0.045-0.050

- -

+0.012+0.014+0.017+0.018+0.020

- -

-0.035-0.040-0.045-0.050-0.055-0.063-0.070

+0.014+0.016+0.018+0.020+0.022+0.024+0.029

Reference Dia. d 0.5 Module 7e 0.8 Module 7e

For racks d is assumed to be 100 • normal module.


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UPHG-20RH-K mating with UPHG-80LH-K at JS7 Distance Tolerance.1. Calculate reference diameter for each gear UPHG3.0-20RH-K d1 = (z . mn) / cos b = (20 . 3) / cos 15 = 62.117mm UPHG3.0-80RH-K d2 = (z . mn) / cos b = (80 . 3) / cos 15 = 248.466mm

2. Find Asne and Tsn from tables on previous page UPHG3.0-20RH-K Asne = -0.019mm Tsn = 0.025mm UPHG3.0-80RH-K Asne = -0.026mm Tsn = 0.030mm

3. Calculate Asni for each gearAsni = Asne - Tsn

UPHG3.0-20RH-K Asni1 = -0.044mm UPHG3.0-80RH-K Asni2 = -0.056mm

4. Calculate centre distance and centre distance tolerance a = (d1 + d2) / 2 = (62.117 + 248.466) / 2 = 155.291mm As = ±0.020mm

5. Calculate the change in backlash due to centre tolerance

6. Calculate the maximum backlash Remove the minus sign on Asn

7. Calculate the minimum backlash Remove the minus sign on Asn

8. Convert to angular backlash

1° = 60 arc minutes

Output backlash, i.e. input gear UPHG30-20RH-K fixed.

0.0549 to 0.0148 degrees

Backlash

Example:

· 6880 d2


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Modifications

Keyways to DIN 6885 Js9 sliding fit. D10 free fit and P9 tight fit available on request.Woodruff keyways available on request.Standard bore tolerance H7 ISO 286. Other tolerances available.Special bore shapes available including square and hexagon.

t1

t2

b r

r

h

Keyb x h2 x 23 x 34 x 45 x 56 x 68 x 7

10 x 812 x 8

Shaft bN9

-0.004/-0.029-0.004/-0.029+0.000/-0.030+0.000/-0.030+0.000/-0.030+0.000/-0.036+0.000/-0.036+0.000/-0.043

Bore bJs9

+0.012/-0.012+0.012/-0.012+0.015/-0.015+0.015/-0.015+0.015/-0.015+0.018/-0.018+0.018/-0.018+0.021/-0.021

Nominal1.21.82.53.03.54.05.05.0

Tolerance+0.10/–0.00+0.10/–0.00+0.10/–0.00+0.10/–0.00+0.10/–0.00+0.20/–0.00+0.20/–0.00+0.20/–0.00

Nominal1.01.41.82.32.83.33.33.3

Tolerance+0.10/–0.00+0.10/–0.00+0.10/–0.00+0.10/–0.00+0.10/–0.00+0.20/–0.00+0.20/–0.00+0.20/–0.00

Radiusr

Max – Min0.16 – 0.080.16 – 0.080.16 – 0.080.25 – 0.160.25 – 0.160.25 – 0.160.40 – 0.250.40 – 0.25

Width DepthShaft t1 Bore t2

Bore Size dOver

- 6 810121722303844

Bore Size dIncluding

6 81012172230384450

Keyway Sizeb x h

- 2 x 2 3 x 3 4 x 4 5 x 5 6 x 6 8 x 710 x 812 x 814 x 9

PinHole 1.5 2.0 3.0 4.0 5.0 6.0 8.010.010.010.0

TappedHole

M3 x 0.5 M3 x 0.5 M3 x 0.5 M4 x 0.7 M5 x 0.8 M6 x 1.0 M8 x 1.25 M10 x 1.5 M10 x 1.5 M12 x 1.75


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The selection of correct lubrication for gears involves a wide range of factors to be considered. It is advised you consult lubrication manufacturers/suppliers with your application or review DIN 51509-1 for oil lubrication or DIN 51509-2 for grease (semi-fluid) lubrication or ISO TR 18792 “Lubrication of industrial gear drives” or the America standard ANSI/AGMA 9005-E02.

Greases and oils are available with a range of properties to suit materials used in the gears and environmental conditions. These properties help with anti-foaming, corrosion, oxidation and wear. Plus extreme pressure (EP) additives to help with severe loading conditions.

One of the key factors is choosing the correct Kinematic viscosity of the lubrication. The following equation gives an initial starting point and is based on the pitch line velocity of a spur or helical gear only. The equation assumes an ambient temperature of 10-25°C. Over this the Kinematic viscosity must be increased.

Kinematic viscosity at 40°C (cSt) = 500 . vg-0.5

vg = pitch line velocity m/s = (η . d . n)/60000n = speed in rpm. d = reference diameter in mm

The widely recognised units of viscosity are the centistoke (cSt). It is used by ISO (International Organization for Standardization) to create a classification grade of viscosity. Once a designer has an idea on the viscosity needed, lubrication products can be quickly sorted by checking for the viscosity class.

For grease a similar classification called NLGI consistency number is used to expresses a measure of the relative hardness of grease. It is measured at 25°C.

Due to the sideway sliding motion in worm and wheel gear pairs, and the resulting higher temperatures, they tend to require oils with an ISO VG of 460 and higher. They also require good thermal and oxidative stability. The types of oils used to lubricate worm and wheel gear pairs are compounded mineral oils, EP mineral gear oils and synthetics. See International Standards for a more detailed study.

Lubrication

ISO Viscosity class Mid-point

Kinematic viscosity at 40°C[mm2/s = cSt]

Minimum MaximumISO VG 32 32 28.8 35.2ISO VG 46 46 41.4 50.6ISO VG 68 68 61.2 74.8ISO VG 100 100 90.0 110.0ISO VG 150 150 135.0 165.0ISO VG 220 220 198.0 242.0ISO VG 320 320 288.0 352.0ISO VG 460 460 414.0 506.0ISO VG 680 680 612.0 748.0ISO VG 1000 1,000 900.0 1,100.0ISO VG 1500 1,500 1,350.0 1,650.0


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Three methods of lubrication are widely used.

Grease Lubrication:

Used on low speed, low load applications up to pitch velocities of 5m/s in some cases. Can be used for open or enclosed systems and is applied directly to the gear teeth. As with oils, amount applied is important. Over fill will result in excess losses in the system and temperature build up. The fluidity of the grease is an important factor. Too high or low and lubrication will not be maintained on the gear teeth. Too low and the grease can be lost in the structure of the system. Too high and the gear teeth can simply dig out channels in the lubrication. A key measure of this is “core penetration”.

Splash (Oil Bath) Lubrication:

Used on enclosed systems, one or more gears sit in a bath of oil. Pitch velocities of 3m/s and above are needed to make the system effective. Oil level and temperature limitations must be considered. The temperature of the system (gears, lubrication, and structure) will increase in operation. As temperature increases, viscosity lowers. Care must be taken to ensure temperatures do not rise above limits of the lubrication and the viscosity does not drop to lower than at the required operating conditions. Excess temperature will degrade the lubrication plus cause deformation of gears, shafts and structure leading to reduced backlash and higher friction in the system. For oil level, if too high there will be excess losses in the system. Too low and effective lubrication will not be formed on the teeth plus heat cannot be removed from the meshing teeth. Note the oil level will be lower in the system when operating compared to static. Static levels may have to be increased to maintain the level due in operation. General guidance on oil levels is as follows below.

Lubrication

1/3 h1 h

1 h3 h

Vertical Shaft

Horizontal Shaft

1/2 d11/4 d1

1/3 d2

Forced Oil System:

In a forced oil system lubrication is applied to the contact area of the mating gears by an oil pump. This can be in the form of drops, spray or an oil mist. This method is used on high speed gearing and large sized gearboxes. The method is applicable to pitch line velocity of approximately 12m/s and above for spur or helical and 10m/s for worm and wheel. We recommend you contact lubrication manufacturers/suppliers if considering this method.


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Shaft and Bore Limits & FitsHousing Bore Tolerances (deviation from nominal dimensions)

-36

10183040506580

100120140160180200225250280315355400450

36

10183040506580

100120140160180200225250280315355400450500

-20-30-40-50-65-80-80

-100-100-120-120-145-145-145-170-170-170-190-190-210-210-230-230

-26-38-49-61-78-96-96

-119-119-142-142-170-170-170-199-199-199-222-222-246-246-270-270

-14-20-25-32-40-50-50-60-60-72-72-85-85-85

-100-100-100-110-110-125-125-135-135

-20-28-34-43-53-66-66-79-79-94-94

-110-110-110-129-129-129-142-142-161-161-175-175

-6-10-13-16-20-25-25-30-30-36-36-43-43-43-50-50-50-56-56-62-62-68-68

-12-18-22-27-33-41-41-49-49-58-58-68-68-68-79-79-79-88-88-98-98

-108-108

-2-4-5-6-7-9-9

-10-10-12-12-14-14-14-15-15-15-17-17-18-18-20-20

-6-9

-11-14-16-20-20-23-23-27-27-32-32-32-35-35-35-40-40-43-43-47-47

00000000000000000000000

-4-5-6-8-9

-11-11-13-13-15-15-18-18-18-20-20-20-23-23-25-25-27-27

00000000000000000000000

-6-8-9

-11-13-16-16-19-19-22-22-25-25-25-29-29-29-32-32-36-36-40-40

Over Incl. High Low High Low High Low High Low High Low High Low

Tolerance of Housing Shaft Diameter (Unit = 0.001mm)d6 e6 f6 g5 h5 h6

Nominal Diameter mm

-36

10183040506580

100120140160180200225250280315355400450

36

10183040506580

100120140160180200225250280315355400450500

+12+18+22+27+33+41+41+49+49+58+58+68+68+68+79+79+79+88+88+98+98

+108+108

+6+10+13+16+20+25+25+30+30+36+36+43+43+43+50+50+50+56+56+62+62+68+68

+16+22+28+34+41+50+50+60+60+71+71+83+83+83+96+96+96

+108+108+119+119+131+131

+6+10+13+16+20+25+25+30+30+36+36+43+43+43+50+50+50+56+56+62+62+68+68

+8+12+14+17+20+25+25+29+29+34+34+39+39+39+44+44+44+49+49+54+54+60+60

+2+4+5+6+7+9+9

+10+10+12+12+14+14+14+15+15+15+17+17+18+18+20+20

+12+16+20+24+28+34+34+40+40+47+47+54+54+54+61+61+61+69+69+75+75+83+83

+2+4+5+6+7+9+9

+10+10+12+12+14+14+14+15+15+15+17+17+18+18+20+20

+6+8+9

+11+13+16+16+19+19+22+22+25+25+25+29+29+29+32+32+36+36+40+40

00000000000000000000000

+10+12+15+18+21+25+25+30+30+35+35+40+40+40+46+46+46+52+52+57+57+63+63

00000000000000000000000


Tolerance of Housing Bore Diameter (Unit = 0.001mm)F6 F7 G6 G7 H6 H7

Nominal Diameter mm

Surface Finish Conversion ChartMicro Inch (Cla)

1248

163263

125250500

1,000

Metric (microns) Equivalent (Ra)0.0250.0500.1000.2000.4000.8101.6003.1806.350

12.70025.400

EuropeanN1N2N3N4N5N6N7N8N9N10N11


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Shaft and Bore Limits & FitsHousing Bore Tolerances (deviation from nominal dimensions)

-36

10183040506580

100120140160180200225250280315355400450

36

10183040506580

100120140160180200225250280315355400450500

00000000000000000000000

-10-12-15-18-21-25-25-30-30-35-35-40-40-40-46-46-46-52-52-57-57-63-63

00000000000000000000000

-14-18-22-27-33-39-39-46-46-54-54-63-63-63-72-72-72-81-81-89-89-97-97

00000000000000000000000

-25-30-36-43-52-62-62-74-74-87-87

-100-100-100-115-115-115-130-130-140-140-155-155

00000000000000000000000

-40-48-58-70-84

-100-100-120-120-140-140-160-160-160-185-185-185-210-210-230-230-250-250

+2+3+4+5+5+6+6+6+6+6+6+7+7+7+7+7+7+7+7+7+7+7+7

-2-2-2-3-4-5-5-7-7-9-9

-11-11-11-13-13-13-16-16-18-18-20-20

+4+6+7+8+9

+11+11+12+12+13+13+14+14+14+16+16+16+16+16+18+18+20+20

-2-2-2-3-4-5-5-7-7-9-9

-11-11-11-13-13-13-16-16-18-18-20-20


Tolerance of Housing Shaft Diameter (Unit = 0.001mm)h7 h8 h9 h10 j5 j6

Nominal Diameter mm

-36

10183040506580

100120140160180200225250280315355400450

36

10183040506580

100120140160180200225250280315355400450500

+14+18+22+27+33+39+39+46+46+54+54+63+63+63+72+72+72+81+81+89+89+97+97

00000000000000000000000

+25+30+36+43+52+62+62+74+74+87+87

+100+100+100+115+115+115+130+130+140+140+155+155

00000000000000000000000

+40+48+58+70+84

+100+100+120+120+140+140+160+160+160+185+185+185+210+210+230+230+250+250

00000000000000000000000

+2+5+5+6+8

+10+10+13+13+16+16+18+18+18+22+22+22+25+25+29+29+33+33

-4-3-4-5-5-6-6-6-6-6-6-7-7-7-7-7-7-7-7-7-7-7-7

+4+6+8

+10+12+14+14+18+18+22+22+26+26+26+30+30+30+36+36+39+39+43+43

-6-6-7-8-9

-11-11-12-12-13-13-14-14-14-16-16-16-16-16-18-18-20-20

Over Incl. High Low High Low High Low High Low High Low

Tolerance of Housing Bore Diameter (Unit = 0.001mm)H8 H9 H10 J6 J7

Nominal Diameter mm

Tolerance Band in Microns (0.001mm) Unitsover

036

10183050

incl.36

1018305080

m6 +2 / +8 +4 / +12 +6 / +15 +7 / +18 +8 / +21 +9 / +25 +11 / +30

S7 -6 / -16 -10 / -22 -13 / -28 -16 / -34 -20 / -41 -25 / -50 -30 / -60

precision ground gears - ondrives · pdf fileprecision ground gears ... reference profiles din...

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