• Worm Gear Design Calculator
• Worm Gear Design Calculation Pdf Viewer Download
• Gear Calculation Formula Pdf
• Worm Gear Design Calculation Pdf Viewer Software

DESIGN PROCEDURE FOR SPUR GEAR:

Worm Gear Design Calculation. A worm gear box must contain a worm and a mating gear (helical gear) and normally the axis of the worm is perpendicular to the axis of the gear. Look at the picture below: Where, D1 – Pitch Diameter of Worm. D2 – Pitch Diameter of Gear. C – Centre to Centre Distance between the Worm and the Gear. The individual calculations are numbered (see figure) and a list of them is shown hereinafter. By clicking on the link a full calculation listing is displayed. Specification and calculation results: vbelt01example1en.pdf. External spur gear. Specification and calculation results: Gear101example1en.pdf. PDF On Dec 31, 2014, B. Magyar and others published Calculation of the efficiency of worm gear drives Find, read and cite all the research you need on ResearchGate.

1.Calculation of gear ratio (i):

where, NA and NB = speed of the driver and driven respectively, and ZA and ZB = Number of teeth on driver and driven respectively.

2.Selection of material

Consulting Table 5.3, knowing the gear ratio i, choose the suitable material.

3.If not given, assume gear life (say 20000 hrs)

4.Calculation of initial design torque:

[Mt] = Mt . K. Kd

where, [Mt] = transmission torque

K = Load factor, Table 5.11

Kd = Dynamic load factor, Table 5.12

Assume K. Kd = 1.3 ( if not given)

5.Calculation of Eeq, [ϭb] and [ϭc]:

üFrom table 5.20 Calculate Eeq

üFrom table 5.16 Calculate Design bending stress [ϭb]

üCalculate Design contact stress [ϭc] by

[ϭc] = CB . HB. Kcl (or)

[ϭc] = CR . HRC. Kcl

where, CB CR = Coefficient of surface hardness from table 5.18

HB HRC = Hardness number

6. Calculation if centre distance (a):

6.Select number of teeth on gear and pinion:

Worm Gear Design Calculator

ØOn pinion,Z1 = Assume 18

Ø On gear, Z2 = i X Z1

8.Calculation of module:

Choose standard module from table 5.8

9. Revision of centre distance(m)

10. Calculate b, d1, v and ѱp :

 Calculate face width, b = ѱ. a

 Calculate pitch dia, d = m.z1

 Calculate pitch line velocity, v = (πd1N1)/60

 Calculate value of ѱp = b/d1

11. Selection of quality of gear:

Knowing the pitch line velocity and consulting table 5.22, select a suitable quality

of gear.

12. Revision of design torque [Mt]: Revise K:

Using the calculated value of ѱp revise the K value by using table 5.11

Revise Kd:

Using the selected quality if gear and pitch line velocity, revise the Kd

value

[Mt] = Mt . K. Kd

13. Check for bending:

14. Check for wear strength:

Calculate induced contact stress,

15. If the design is not satisfactory (ϭb > [ϭb] and / or ϭc > [ϭc] ), then increase the module of face width value of the gear material.

16. Check for gear:

a.Check for bending:

If Ϭb2 ≤ [Ϭb2], then design is safe.

b.Check for wear strength:

Calculate induced contact stress will be same for pinion and gear,

So,

Ϭc2 = Ϭc

üCompare Ϭc and [Ϭc]

üIf Ϭc ≤ [Ϭc], then design is safe

Worm Gear Design Calculation Pdf Viewer Download

Resources:

Spur Gear design formula for geometry, pitch, tooth clearance and critical functional data.
(Inch Units Applicable for Constants)

Where:
φ = Pressure Angle
a = Addendum
a_G = Addendum of Gear
a_P = Addendum of Pinion
b = Dedendum
c = Clearance
C = Center Distance
D = Pitch Diameter
D_G = Pitch Diameter of Gear
D_P = Pitch Diameter of Pinion
D_B = Base Circle Diameter
D_O = Outside Diameter
DR = Root Diameter
F = Face Width
h_k = Working Depth of Tooth
h_t = Whole Depth of Tooth
m_G = Gear Ratio
N = Number of Teeth
N_G = Number of Teeth in Gear
N_P = Number of Teeth in Pinion
p = Circular Pitch
P=Diametral Pitch

Equations for Standards Spur Gears

Gear Calculation Formula Pdf

Formulas for Tooth Parts, 20-and 25-degree Involute Full-depth Teeth
ANSI Coarse Pitch Spur Gear Tooth Forms ANSI B6.1

Equations Tooth Parts, 20-and 25-degree Involute Full-depth Teeth ANSI Coarse Pitch Spur Gear Tooth Forms ANSI B6.1

^a When gears are preshave cut on a gear shaper the dedendum will usually need to be increased to 1.40/P to allow for the higher fillet trochoid produced by the shaper cutter. This is of particular importance on gears of few teeth or if the gear blank configuration requires the use of a small diameter shaper cutter, in which case the dedendum may need to be increased to as much as 1.45/P. This should be avoided on highly loaded gears where the consequently reduced J factor will increase gear tooth stress excessively.
^b A minimum clearance of 0.157/P may be used for the basic 20-degree and 25-degree pressure angle rack in the case of shallow root sections and use of existing hobs or cutters.
^c The fillet radius of the basic rack should not exceed 0.235/P for a 20-degree pressure angle rack or 0.270/P for a 25-degree pressure angle rack for a clearance of 0.157/P. The basic rack fillet radius must be reduced for teeth with a 25-degree pressure angle having a clearance in excess of 0.250/P.

Helical Gear

Circular Pitches and Equivalent Diametral Pitches Table

Worm Gear Design Calculation Pdf Viewer Software

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