Worm and wheel gear sets are used for steering gear, winch blocks, e.g. See Figure 11.2, low-speed gearboxes, rotary tables, and remote valve control. Worm and wheel gear sets are Mechanical. G-59 Worm and Worm Gears 4 Pitch. 11/ 2' Face. 141/ 2° Pressure Angle Right Hand Single Thread (Stocked Right Hand Only) Cast Iron Steel — 4° 46' Helix Angle Worms Case hardened worms have ground and polished threads (Indicated by letter “G” in catalog number).

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,

Calculations for worm gears are the same as for. Worm Gearing 50 Lead Angle Worm threads are. Perature and the details of the gear mesh design. Worm gear.pdf - Free download as PDF File (.pdf), Text File (.txt) or read. Of a worm gear is related to its circular pitch and number of teeth Z by the formula.

D1 – Pitch Diameter of Worm

D2 – Pitch Diameter of Gear

C – Centre to Centre Distance between the Worm and the Gear

This worm gear design tutorial will discuss up to the selection of the module and pitch and the calculation of the number of teeth, pitch circle diameter and centre to centre distance between the worm and gear. We will use the AGMA formulae for doing the calculations. Design calculations of the other aspects of the worm gear will be discussed in a subsequent part of the tutorial.

Steps of the Design Calculation

The axial pitch of the worm and the circular pitch of the gear must be same for a mating worm and gear. We will use the term Pitch (P) for both the pitch in this tutorial.
Also, the module of the worm as well as the gear must be equal for a mating worm and gear.
Now, let’s say we have the following design input:

Speed of the Worm (N1) = 20 RPM

Speed of the Gear (N2) = 4 RPM

And, we have to find out the Module (m), Pitch (P), Number of helix of Worm (T1), Number of teeth of Gear (T2), Pitch circle diameter of Worm (D1), Pitch circle diameter of Gear (D2), Centre to centre distance(C).

Select the suitable module and its corresponding pitch from the following AGMA specified table:

Module m (in MM) – Pitch P (in MM)

2 ————————-6.238

Worm Gear Calculation

Worm Gear Design Pdf

2.5 ———————- 7.854

3.15 ——————— 9.896

4 ————————- 12.566

5 ————————- 15.708

6.3 ———————– 19.792

8 ————————– 25.133

10 ————————- 31.416

12.5 ———————– 39.27

16 ————————– 50.625

20 ————————– 62.832

Say, we are going ahead with the Module as 2 and the Pitch as 6.238.

Use the following gear design equation:

N1/N2 = T2/T1

Worm Gear Design Calculation Pdf