Spur GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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Description Symbol Unit EquationNormal Module mnTransverse Module mt = mnNormal Pressure Angle αn degrees = 20°Transverse Pressure Angle αt degrees = αnNumber 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 · mnTip Diameter da mm = d + (2mn · x) + (2 · mn)Root Diameter dr mm = da – (2 · h)Normal Pitch pn mm = π · mnNormal Tooth Thickness in Pitch Circle sn mm = (pn / 2) + 2mn · x · tan αn
When working with a pair of gears the subscript 1 & 2 denotes input (drive) and output (driven) gear.Tip diameter is the theoretical diameter of the gear without tooth thickness tolerance applied.For sn at x = zero, this is the theoretical tooth thickness. Actual tooth thickness will be less. The subscript e is for upper allowance values and i for lower allowance values.
da1 dr1
sn
pn
a
d1
Spur GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
� [email protected]� www.ondrives.com
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Gear QualityStandard metal gears are supplied to quality Grade 7 DIN 3961 based on Pitch total deviation Fp, Pitch deviation fp, Radial runout Frand Pitch error fu. Skive hobbed gears are supplied to quality Grade 6 DIN 3961. GG25 Cast Iron, PEEK GF30® and Delrin (POM) are supplied to quality Grade 8 DIN 3961.Ondrives can manufacture gears to higher grades on request. Ondrives can offer testing certification for a gear’s individualparameters using the latest CMM machine with gear measuring software.Double and single flank testing is available on request. Please contact our technical department for details.
Comparisons of Grade StandardsExample 3 mod, 50 teeth, 30mm face width spur gear
TorqueStated value for metal spur gears is maximum torque (T2) based on two identical gears with the same number of teeth running atstandard centres. Value is minimum from surface stress or bending stress.Other factors including duty cycle and temperature will affect maximum allowable torque and service life. Wear is dependant onlubrication. We recommend that each user compute their own values based on actual operating conditions and test in application.
Stated value for plastic spur gears is maximum torque (T2) based on two identical gears with the same number of teeth running atstandard centres. Value is minimum from surface stress, bending stress or bulk/suface temperature using method from BS 6168:1987.The torque capacity of plastic gears is highly dependant on operating condition. All values are reference only. We recommend thateach user test in application under specific operation conditions of application.
* Reference Only ** Approximate value based on initial light greasing.
Maximum torque for titanium gears is approximatey 30% of 817M40 steel gears.Due to lack of stress factors we are unable to offer specific values. Testing in application is required.
Torque for anti-backlash spur gears is limited by the spring rating. Please contact our Technical department for details.
When selecting gears application factors should be applied to required torque.
T2 > T required x Ka
Application factor Ka
Pitch total deviation Fp µm 32 44 50 51Pitch deviation fp µm 8 12 13 13Radial runout Fr µm 22 31 40 41Pitch error fu µm 10 15 - -Double flank composite transmission error Fi" µm 26 36 61 61Double flank tooth-to-tooth transmission error fi" µm 11 15 21 20
StandardGrade
DIN 39616
DIN 39617
ISO 13287
AGMA10
MaterialsInput SpeedBending Stress Factor SbSurface Stress Factor Sc
817M40
320003000
805M20
5000011000
303 Stainless
200001800
316 Stainless
158001400
GG25 Cast Iron
76001350
100 rpm Uniform, 12 hours running per day
MaterialsInput Speed / No. of Load CyclesLimiting Bending StressLimiting Surface StressInitial TemperatureMax. Bulk or Surface TemperatureCoefficient of Friction
Delrin POM (White)100 rpm / 108
22.0 N/mm2
13.5 N/mm2
20°C60°C
0.18 (Dry)
PEEK GF30® (Light Brown)100 rpm / 108
30 N/mm2*80 N/mm2*
20°C80°C
0.25**
Working characteristicsof driving machineUniformLight ShocksModerate ShocksHeavy Shocks
Uniform1.001.101.251.50
LightShocks
1.251.351.501.75
ModerateShocks
1.501.601.752.00
HeavyShocks
1.751.852.002.25+
Working characteristics of driven machine
Parallel Helical GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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Description Symbol Unit EquationNormal Module mnTransverse Module mt = mn / cos βAxial Module mx = mn / sin βNormal Pressure Angle αn degrees = 20°Transverse Pressure Angle αt degrees = tan-1 (tan αn / cos β)Helix Angle β degrees = 15°Lead Angle λ degrees = 90 - βNumber 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 βTip Diameter da mm = d + (2mn · x) + (2 · mn)Root Diameter dr mm = da – (2 · h)Normal Pitch pn mm = π · mnTransverse Pitch pt mm = π · mt = (π · mn) / cos βAxial Pitch px mm = π · mx = (π · mn) / sin βNormal Tooth Thickness in Pitch Circle sn mm = (pn / 2) + 2mn · x · tan αnTransverse Tooth Thickness in Pitch Circle st mm = (pt / 2) + 2mn · x · tan αt
When working with a pair of gears the subscript 1 & 2 denotes input (drive) and output (driven) gear.Tip diameter is the theoretical diameter of the gear without tooth thickness tolerance applied.For sn & st, 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 for lower allowance values.For two helical gears to run together one must be left hand and the other right hand helix.
da1 dr1
st
pt
aβ
d1
Parallel Helical GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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TorqueStated value is maximum torque (T2) based on two identical gears with the same number of teeth running at standard centres.Value is minimum from surface stress or bending stress.Other factors including duty cycle and temperature will affect maximum allowable torque and service life. Wear is dependant onlubrication. We recommend that each user compute their own values based on actual operating conditions and test in application.
When selecting gears application factors should be applied to required torque.
T2 > T required x Ka
Application factor Ka
Pitch total deviation Fp µm 47 50 55Pitch deviation fp µm 12 13 12Radial runout Fr µm 31 40 44Pitch error fu µm 15 - -Double flank composite transmission error Fi" µm 36 61 65Double flank tooth-to-tooth transmission error fi" µm 15 21 20
StandardGrade
DIN 39617
ISO7
AGMA10
MaterialsInput SpeedBending Stress Factor SbSurface Stress Factor Sc
817M40
320003000
805M20
5000011000
303 Stainless
200001800
316 Stainless
158001400
100 rpm Uniform, 12 hours running per day
Gear QualityStandard gears are supplied to quality grade 7e25 DIN 3961 based on the following parameters
Radial Runout Fr =
Pitch Deviation fp =
Total Pitch Deviation Fp =
Pitch Error fu =
Ondrives manufacture gears to higher quality grades on request. Ondrives can offer testing certification of a gears individualparameters using the latest CMM machine with gear measuring software. Double and single flank testing is available on request.Please contact our technical department for details.
Comparisons of Grade StandardsExample 3 mod, 50 teeth, 30mm face width 15° helix parallel helical gear
1 68 2 18 2 3 1 2 1 4 11
4. . . . log • • . •+ + +( )( )( )m m dn n
4 0 315 0 25 1 4 1 4+ +( )( )( ). . • . • .m dn
5 0 4 0 25 1 4 1 4+ +( )( )( ). . • . • .m dn
7 25 1 4 11
3
17
. • • . • .d
z
⎛
⎝⎜⎜
⎞
⎠⎟⎟
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟
Working characteristicsof driving machineUniformLight ShocksModerate ShocksHeavy Shocks
Uniform1.001.101.251.50
LightShocks
1.251.351.501.75
ModerateShocks
1.501.601.752.00
HeavyShocks
1.751.852.002.25+
Working characteristics of driven machine
Crossed Axis Helical GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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Description Symbol Unit EquationNormal Module mnTransverse Module mt = mn / cos βAxial Module mx = mn / sin βNormal Pressure Angle αn degrees = 20°Transverse Pressure Angle αt degrees = tan-1 (tan αn / cos β)Helix Angle β degrees = 45°Lead Angle λ degrees = 90 - βNumber 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 βTip Diameter da mm = d + (2mn · x) + (2 · mn)Root Diameter dr mm = da – (2 · h)Normal Pitch pn mm = π · mnTransverse Pitch pt mm = π · mt = (π · mn) / cos βAxial Pitch px mm = π · mx = (π · mn) / sin βNormal Tooth Thickness in Pitch Circle sn mm = (pn / 2) + 2mn · x · tan αnTransverse Tooth Thickness in Pitch Circle st mm = (pt / 2) + 2mn · x · tan αt
When working with a pair of gears the subscript 1 & 2 denotes input (drive) and output (driven) gear.Tip diameter is the theoretical diameter of the gear without tooth thickness tolerance applied.For sn & st, 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 for lower allowance values.For two crossed axis helical gears to run together both must be right hand or left hand helix.
da1
px
st
pt
β
λ
a
d1
Crossed Axis Helical GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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TorqueStated value is maximum torque (T2) based on two identical gears with the same number of teeth running at standard centres.Crossed axis helical gears transmit load by point contact. The limiting condition is typically surface stress.Other factors including duty cycle and temperature will affect maximum allowable torque and service life.Wear is dependant on lubrication.We recommend that each user compute their own values based on actual operating conditions and test in application.
When selecting gears application factors should be applied to required torque.
T2 > T required x Ka
Application factor Ka
MaterialsInput SpeedBending Stress Factor SbSurface Stress Factor ScLubricationLubrication Viscosity
817M40
320003000
805M20 (SAE 8620) Case Hd.
5000011000
100 rpm Uniform speed
Mineral OilBetween 60mm2/s and 130mm2/s at 60°C
Direction of Rotation
Right Hand Helix Left Hand Helix
Working characteristicsof driving machineUniformLight ShocksModerate ShocksHeavy Shocks
Uniform1.001.101.251.50
LightShocks
1.251.351.501.75
ModerateShocks
1.501.601.752.00
HeavyShocks
1.751.852.002.25+
Working characteristics of driven machine
Worms & WheelsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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Description Symbol Unit EquationAxial Module mxNormal Module mn = mx · cos λNormal Pressure Angle αn degrees = 20°Transverse Pressure Angle αt degrees = tan-1 (tan αn / cos λ)Lead Angle λ degrees = tan-1 ((mx · z1) / d2)Helix Angle β degrees = 90 - λNumber 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 λReference 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 = π · mnAxial Pitch px mm = π · mxNormal Tooth Thickness in Pitch Circle sn mm = sx · cos λTransverse Tooth Thickness in Pitch Circle sx mm = (px / 2)
Gear Quality: Steel and Stainless Steel Worm = 6 DIN 3974, Bronze Wheel = 7 DIN 3974. PEEK and Delrin Worms 7 DIN 3974, PEEK and Delrin Wheel = 8 DIN 3974.When working with a gear set the subscript 1 denotes a worm and 2 a wheel. Tip diameter is the theoretical diameter of the gear without tooth thickness tolerance applied.For sn & 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 for lower allowance values.
d2 dr2 da2 de2
a
X N
λλ
N Xd1
Worms & WheelsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
� [email protected]� www.ondrives.com
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TorqueStated value is maximum torque based on lowest figure from surface durability, tooth root strength or wear.Values for bronze and cast iron wheel are for matching with steel 817M40 worm.Value is output torque T2 at wheel.Tooth root failure of teeth on wheel before teeth of worm is assumed.
Other factors including worm shaft deflection, duty cycle and temperature will affect maximum allowable torque and service life.Wear is dependant on lubrication.We recommend that each user compute their own values based on actual operating conditions and test in application.
Input SpeedLifeLimiting Stress N/mm2 (CA104)Limiting Stress N/mm2 (GG25)LubricationLubrication ViscosityApplication Factor
Surface Durability
15.24.1
Tooth Root Strength
6940
100 rpm Uniform Speed25,000 hours
Mineral OilBetween 60mm2/s and 130mm2/s at 60°C
1.00
Axial SectionNormal Section
pn
dr1 d1 da1
sn px sx
ha
hf
Working characteristicsof driving machineUniformLight ShocksModerate ShocksHeavy Shocks
Uniform1.001.101.251.50
LightShocks
1.251.351.501.75
ModerateShocks
1.501.601.752.00
HeavyShocks
1.751.852.002.25+
Working characteristics of driven machine
Maximum torque as % of CA104 Aluminium Bronze WheelMaximum Wheel Temperature
Delrin POM 50%*60°C
PEEK GF30®55 - 65%*
80°C
* Approximate value based on plastic wheel running with steel worm to allow initial selection. Testing in application will be required.
Torque for anti backlash wormwheel gears is limited by the spring rating. Please contact our Technical department for details.
When selecting worm application factors should be applied to required torque.
T2 > T required x Ka
Application factor Ka
Worms & WheelsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
� [email protected]� www.ondrives.com
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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 dependant on lubrication and the figures below do not include bearing, seal and other losses.
Coefficient of friction µ (Mineral Oil)
η = tan λ / tan (λ+ pz)pz = arctan (µ)vg = (d1 · n1) / (19098 . tan λ)T1= (T2 / u) * η
T1= Input Torque (Nm)T2= Output Torque (Nm)u = Ratioη = Efficiencyλ = Lead Angle (degrees)μ = Coefficient of Frictionpz = Angle of Frictionvg = Sliding Speed (m/s)n1= rpm of Wormd1= Pitch 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
Worms & WheelsP R E C I S I O N G E A R S
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CCHH
NNII
CCAA
LL
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Gear Forces and Direction of Rotation
Ftm1 = 2000*(T1 / d1) = - Fxm2Ftm2 = 2000*(T2 / d2) = - Fxm1Frm1 = Ftm1*[tan 20 / (sin λ + pz) ] = - Frm2
pz = arctan (μ)Ftm = Tangential force (N)Fxm = Axial force (N)Frm = Radial force (N)The subscript 1 and 2 relate to the worm and wheel.
Ondrives worm and wheel gears are supplied right hand lead as standard.The black arrows show the direction of rotation.
Ftm1 = -Fxm2
Frm1 = -Frm2
Ftm2 = -Fxm1
Bevel GearsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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Description Symbol Unit EquationNormal Module mnPressure Angle α degrees = 20°Shaft Angle Σ degrees = (90° for Ondrives standard gears)Number of Teeth z1, z2Gear Ratio u = z2 / z1Pitch Diameter of Worm d1, d2 mm = z · mnPitch Cone Angle δ1 degrees = δ1 = tan-1 (sin Σ / (u + cos Σ))Pitch Cone Angle δ2 degrees = δ2 = Σ - δ1Cone Distance Re mm = d2 / 2 sin δ2Addendum ha mm = 1.00 · mn (for Ondrives standard gears)Dedendum hf mm 0.6 to 1.0mn = 1.25 · mn (standard gears)
1.5 to 2.0mn = 1.22 · mn (standard gears)4.0mn = 1.20 · mn (standard gears)
Outside Diameter da mm = d + 2 ha · cos δPitch Apex to Crown X mm = Recos δ - hasin δ
Quality Grade 7 DIN 3965
TorqueStated value is maximum torque (T2) based on two identical gears with the same number of teeth running at standard centres.Value is minimum from surface stress or bending stress.Other factors including duty cycle and temperature will affect maximum allowable torque and service life.Wear is dependant on lubrication.We recommend that each user compute their own values based on actual operating conditions and test in application.
MaterialsInput SpeedBending Stress Factor SbSurface Stress Factor Sc
817M40
320003000
805M20
5000011000
303 Stainless
200001800
316 Stainless
158001400
100 rpm Uniform, 12 hours running per day
da
F
hahf
δ1
δ2
d
X
Re
MaterialsP R E C I S I O N G E A R S
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Ondrives can manufacture gears in a range of additional materials including bronzes, engineering plastics, special steels andstainless steels.Gears can be heat treated by a range of methods to improve performance.Please contact our Technical sales team who will be happy to discuss your specific requirements.
805M20817M40T080M40
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)78507850785078508000800077807580860084701490141072004420
Elongationafter
Fracture11%
5-13%7-17%13%
35-45%40%10%15%5%
20%2.70%30%
-10-18%
TensileStrength(N/mm2)
980850-100510-600
850-1000480-510
5151103
750360-500
410156
67145-195
895-1000
0.2% ProofStress
(N/mm2)785680340650
180-200205100430
170-280200
---
828-910
B.S. 970 817M40T805M20303S21316S16080M40655M13722M24
PB2CA104
Brass CZ121
B.S. 1452Cast Iron 250
Titanium Ti-6AL-4V
En24T3625858J83640B
ISOCu89Sn11
GZ-CuAL10NiCuZn39Pb3
EnEN-GJL-250
B.S.2TA11
DIN40NiCrMo8-4 / 34CrNiMo620NiCrMo2-2 / 20NiCrMo2
X10CrNiS189X5CrNiMo17133
C4014NiCr1432CrMo12
CuSn12CuAL10Ni
-
DINDIN 1691 GG25
UNSR56400
Werkstoff1.6562, 1.6582
1.65231.43051.44361.05111.57521.7361
Werkstoff3.7165
SAE/AISI4340, 4337
86203033161040
3415, 3310, 9314-
SAE 64ASTM B150 UNC C63200
UNC C38500
AMS4911/4928
Material Equivalents
MaterialsP R E C I S I O N G E A R S
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General PropertiesDensityAbsorption of Moisture
Mechanical propertiesYield Stress/ Tensile StrengthElongation at BreakTensile Modulus of ElasticityBall Indentation HardnessShore - HardnessCoefficient of Friction against hardened and ground steel (dry)
Thermal PropertiesMelting TemperatureThermal Properties Coefficient of Linear Thermal ExpansionService Temperature, long term (min.)Service Temperature, long term (max.)Service Temperature, short termHeat Deflection Temperature
Electrical Properties Dielectric Constant Dielectric Dissipation FactorSpecific Volume ResistivitySurface ResistivityComparative Tracking Index (test solution A)Dielectric Strength
kg/m3
N/mm2
N/mm2
N/mm2
Skala D
°CW / (m · K)
10-6 K-1
°C°C°C°C
Ω · cmΩ
kV/mm
Delrin POM1410
0.20%
6730.0%2800
15081
0.10-0.30
1650.31110-50100140110
3.800.00210131013
60040
PEEK GF30®1490
0.14%
1562.7%9700
23088
0.38-0.46
3430.43
30-20250310315
3.200.00110141013
17520
Delrin POM (White)DIN EN ISO 1043-1: POM C | polyacetal comopolymer.
Very good dimensional stabilitycompared to Nylon & Hostaform.
Minimal absorption of moisture.
Good sliding properties.
High wear resistance.
High surface hardness.
High mechanical strength and stiffnesscompared to Nylon & Hostaform.
Can be in contact with food (FDA).
Delrin gears can be run dry or greased/oiled to improve wear.
PEEK GF30® (Light Brown)DIN EN ISO 1043-1: PEEK | polyetheretherketone.
Excellent dimensional stability.
Outstanding high mechanical strength and hardnessover a broad temperature range.
Shows only a slight distortion under the impact ofmechanical load and high temperature.
Good electrical insulating properties.
Extremely high flame resistance.
Self-extinguishing.
Very low smoke emission in a case of a fire.
Can be run dry for slow speed hand operation.Gears should be greased/oiled for all other operating conditions.
BacklashP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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The backlash figures given for spur, helical and crossed axis helical gears is the theoretical backlash for two identical gears atstandard centre distance to the ISO 286 centre distance tolerance.It is given as circumferential backlash in mm measured on pitch circle diameter. An upper and lower value is quoted.Theoretical backlash is the difference between tooth thickness without and with tolerance applied.Backlash is calculated according to DIN 3967Ondrives can manufacture gears to a wide range of tolerances to suit customer application.Please contact our Technical Sales team who will be happy to discuss your specific requirements.
Tooth Thickness TolerancesGear Type
SpurSpur (Skive hobbed)
PinionsParallel Helical
Crossed Axis HelicalWorm & Wheel
Bevel
Module 0.5 to 0.87e/8e DIN 58405
6e DIN 584057e DIN 584057e DIN 584057e DIN 58405
7e/8e DIN 58405
Module 1.0 to 3.0e25 DIN 3967e25 DIN 3967e25 DIN 3967e25 DIN 3967e25 DIN 3967e25 DIN 3967
Module 0.6 to 4.07f24 DIN 3965/3967
Centre Distance ToleranceJs7Js7-
Js7Js8Js8
Asn = Tooth thickness allowance which is the difference between measured gear tooth thickness and theoretical value measured inthe normal section. When working with a pair of gears the subscript 1 & 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
Units = mm & degrees
Change in Circumferential due to Centre Distance Tolerance ja
Units = mm & degrees
jA A
jtsn sn
a=+
+ Δ1 2
cosβ
j jn t n= • cos • cosα β
Δj Aa sn= 2 • •
tan
cos
αβ
Deviation fromcentre distance
As (mm)0.0010.0100.0150.0200.0250.0300.0350.0400.0450.050
Change inBacklashΔΔja (mm)
0.0010.0070.0110.0150.0180.0220.0250.0290.0330.036
Deviation fromcentre distance
As (mm)0.0010.0100.0150.0200.0250.0300.0350.0400.0450.050
Change inBacklashΔΔja (mm)
0.0010.0080.0110.0150.0190.0230.0260.0300.0340.038
Deviation fromcentre distance
As (mm)0.0010.0100.0150.0200.0250.0300.0350.0400.0450.050
Change inBacklashΔΔja (mm)
0.0010.0100.0150.0210.0260.0310.0360.0410.0460.051
Spur Gear Parallel Helical Gear Crossed Axis Helical Gear
BacklashP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
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Reference Diameterd (mm)
Over Upto- 10
10 5050 125
125 280
Upper ToothThickness Allowance
Asne-0.022mm-0.030mm-0.040mm-0.056mm
ToothThickness Tolerance
Tsn0.020mm0.030mm0.040mm0.050mm
ReferenceDiameterd (mm)
from 3 to 6
above 6 to 12
above 12 to 25
above 25 to 50
above 50 to 100
above 100 to 200
above 200 to 400
NormalModule
mnabove 0.16 to 0.25above 0.25 to 0.6above 0.6 to 1.6
above 0.16 to 0.25above 0.25 to 0.6above 0.6 to 1.6
above 0.16 to 0.25above 0.25 to 0.6above 0.6 to 1.6above 1.6 to 3
above 0.16 to 0.25above 0.25 to 0.6above 0.6 to 1.6above 1.6 to 3
above 0.16 to 0.25above 0.25 to 0.6above 0.6 to 1.6above 1.6 to 3
above 0.6 to 1.6above 1.6 to 3
above 0.6 to 1.6above 1.6 to 3
Upper ToothThickness Allowance
Asne0.0280.0300.0350.0300.0350.0400.0350.0400.0450.0500.0400.0450.0500.0550.0450.0500.0550.0630.0630.0700.0700.080
ToothThickness Tolerance
Tsn0.0110.0120.0140.0120.0140.0160.0140.0160.0180.0200.0160.0180.0200.0220.0180.0200.0220.0240.0240.0290.0290.032
Angular Backlash jθθ
Units = mm & degrees
d2 = Reference diameter (mm)As = centre distance tolerance (i.e. a = 30mm Js7, As = ±0.0105mmαn = Normal pressure angle (αn = 20°)β = Helix angle (β = zero for spur gears)
Replace helix angle β with lead angle λ for worm and wheel.1° = 60 arc minutes
e25 DIN 3967
360 x π x d2
*Asne is converted from base tangent length allowance (Aw) according to Aw = Asn * cos 20°
7e DIN 58405
jθ =jt
Input Gear PSG0.5-20 7eOuput Gear PSG0.5-40 7e
1. Calculate the reference diameter d for each gear
PSG0.5-20 d1 = z * mn = 10.00mmPSG0.5-40 d2 = 20.00mm
2. Find Asne and Tsn from the tables overleaf
PSG0.5-20 Asne = -0.035mm Tsn = -0.014mmPSG0.5-40 Asne = -0.040mm Tsn = -0.016mm
3. Calculate Asni for each gear
PSG0.5-20 Asni = Asne - Tsn = -0.035-0.014 = -0.021mmPSG0.5-40 Asni = Asne - Tsn = -0.040-0.016 = -0.024mm
4. Calculate the centre distance of the two gearsand the centre distance tolerance
centre distance = (10 + 20) / 2 = 15mmJs7 = ±0.009mm
5. Calculate the change in backlash due to centre distance
6. Calculate the maximum backlashRemove the minus sign on Asn
7. Calculate the minimum backlashRemove the minus sign on Asn
8. Convert to angular backlash
1° = 60 arc minutes
28.208 to 13.072 arc minutes
BacklashP R E C I S I O N G E A R S
TTEE
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NNII
CCAA
LL
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Example for Calculating Backlash for Two Non-Identical Gears
Δj A mma sn= + =2 2 0 009
20
00 007• •
tan
cos• . •
tan
cos.
αβ
=+
+ =0 035 0 040
00 007 0
. .
cos. .0082mm
jA A
jtsni sni
a=+
+1 2
cosβΔ =
+− =
0 021 0 024
00 007 0
. .
cos. .0038mm
jA A
jtsne sne
a=+
+1 2
cosβΔ
360 x π x d2
jθ =
jθ =
jt
Limits and FitsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
� [email protected]� www.ondrives.com
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OverInc.
F6
F7
G6
G7
H6
H7
H8
H9
H10
H11
J6
J7
J8
JS6
JS7
JS8
K6
M6
M7
36
18102210124
16480
120
180
300
480
7505
-36
-610-84
-46
-69
-92
-6-1-90
-12
610
22132813145
20590
150
220
360
580
9005
-48
-712
-104.5
-4.57.5
-7.511
-112
-7-3
-120
-15
1018
27163416176
246
110
180
270
430
700
11006
-510-815
-125.5
-5.59
-913.5
-13.52
-9-4
-150
-18
1830
33204120207
287
130
210
330
520
840
13008
-512-920
-136.5
-6.510.5
-10.516.5
-16.52
-11-4
-170
-21
3040
4050
5065
6580
80100
100120
120140
140160
6843834339145414250
400
630
1000
1600
2500
18-726
-1441
-2212.5
-12.520
-2031.5
-31.54
-21-8
-330
-40
160180
180200
200225
7950965044156115290
460
720
1150
1850
2900
22-730
-1647
-2514.5
-14.523
-2336
-365
-24-8
-370
-46
225250
41255025259
349
160
250
390
620
1000
1600
10-614
-1124
-158
-812.5
-12.519.5
-19.53
-13-4
-200
-25
4930603029104010190
300
460
740
1200
1900
13-618
-1228
-189.5
-9.515
-1523
-234
-15-5
-240
-30
5836713634124712220
350
540
870
1400
2200
16-622
-1334
-2011
-1117.5
-17.527
-274
-18-6
-280
-35
Hole Sizes (mm)
Micrometres (10-3m)
Limits and FitsP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
� [email protected]� www.ondrives.com
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OverInc.
f6
f7
g5
g6
g7
h6
h7
h8
h9
h10
h11
j6
j7
js5
js6
js7
k6
m6
m7
36
-10-18-10-22-4-9-4
-12-4
-160
-80
-120
-180
-300
-480
-756
-28
-42.5
-2.54
-46
-691
124
164
610
-13-22-13-28-5
-11-5
-14-5
-200
-90
-150
-220
-360
-580
-907
-210-53
-34.5
-4.57.5
-7.5101
156
216
1018
-16-27-16-34-6
-14-6
-17-6
-240
-110
-180
-270
-430
-700
-1108
-312-64
-45.5
-5.59
-9121
187
257
1830
-20-33-20-41-7
-16-7
-20-7
-280
-130
-210
-330
-520
-840
-1309
-413-8
4.5-4.56.5
-6.510.5
-10.5152
218
298
3040
4050
5065
6580
80100
100120
120140
140160
-43-68-43-83-14-32-14-39-14-54
0-25
0-40
0-63
0-100
0-160
0-250
14-1122
-189
-912.5
-12.520
-20283
40155515
160180
180200
200225
-50-79-50-96-15-35-15-44-15-61
0-29
0-46
0-72
0-115
0-185
0-290
16-1325
-2110
-1014.5
-14.523
-23334
46176317
225250
-25-41-25-50-9
-20-9
-25-9
-340
-160
-250
-390
-620
-1000
-16011-515
-105.5
-5.58
-812.5
-12.5182
259
349
-30-49-30-60-10-23-10-29-10-40
0-19
0-30
0-46
0-74
0-120
0-190
12-718
-126.5
-6.59.5
-9.515
-15212
30114111
-36-58-36-71-12-27-12-34-12-47
0-22
0-35
0-54
0-87
0-140
0-220
13-920
-157.5
-7.511
-1117.5
-17.5253
35134813
Hole Sizes (mm)
Micrometres (10-3m)
Modification PricesP R E C I S I O N G E A R S
TTEE
CCHH
NNII
CCAA
LL
� [email protected]� www.ondrives.com
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Bore Size dOver
-68
10121722303844
Bore Size dIncluding
68
1012172230384450
Keyway Sizebxh
-2x23x34x45x56x68x710x812x814x9
PinHole1.502.003.004.005.006.008.00
10.0010.0010.00
TappedHole
M3x0.5M3x0.5M3x0.5M4x0.7M5x0.8
M6x1.00M8x1.25M10x1.5M10x1.5
M12x1.75
Keybxhmm2x23x34x45x56x68x7
10x812x8
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
Nom1.21.82.53.03.54.05.05.0
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
Nom1.01.41.82.32.83.33.33.3
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
-68
10121722303844
Bore Size dIncluding
68
1012172230384450
BoringOut
£8.25
£12.50
£18.90
KeywaySize
£7.85
£14.30
£20.30
PinHole
£5.10
£6.40
£8.20
TappedHole
£6.20
£7.80
£9.45
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