Worm Dimensions Equations (All dimensions are in inches unless otherwise specified). Axial pitch is used as a basis for this design standard because:ġ) Axial pitch establisheslead which is a basic dimension in the production and inspection of worms Ģ) The axialpitch of the worm is equal to the circular pitch of the gear in the central plane andģ) Only one set of change gears or one master lead cam is required for a given lead, regardless oflead angle, on commonly-used worm-producing equipment. Pitches: Eight standard axial pitches have been established to provide adequate coverageof the pitch range normally required: 0.030, 0.040, 0.050, 0.065, 0.080, 0.100, 0.130, and0.160 inch. L = lead of a worm which is the distance any one thread advances in a single revolution. P n = Normal circular pitch of worm and wormgear = Px cos λ = P cos ψ Calculation of load capacity of wormgears.Related Resources: gears Worm and WormGear Design Equations and CalculatorĮquations for American Standard Fine Pitch Worms and Wormgears This section introduces the dimension calculations for spur gears, helical gears, gear rack, bevel gears, screw gears, and worm gear pairs. ANSI/AGMA Standard 6022-C93.ĪGMA Practice for enclosed cylindrical wormgear speed reducers and gearmotors. Gear dimensions are determined in accordance with their specifications, such as Module (m), Number of teeth (z), Pressureangle (), and Profile shift coefficient (x).
to provide suitable power rating and output torque.ĪGMA Design manual for cylindrical wormgearing. If not, alter the number of starts, worm diameter, center distance, etc. Establish whether the power rating and output torque are sufficient for the application.Ģ0. Estimate the efficiency of the gear set, h.ġ9. Determine the rated input power, Pinput.ġ7. Determine the power lost in mesh, Ploss.ġ6. They are made by breaking down the worm gear couple into a succession ot elementary rack-and-pinion gears, having variable profiles determined in planes parallel to the midplane of the gear. Determine the coefficient of friction, f.ġ5. All of these calculations are based on the application of envelope theory and analytical. Determine the tangential velocity, Vt.ġ2. Determine the ratio correction factor, Cm.ĩ. Determine the maximum recommended face width, F.Ĩ. The following procedure is recommended for designing: Calculate a table of proper solutions 4.1 Sort the results by axis distance 4.5 Select such a solution where the axis distance is close to your requirement and also meets other requirements 4.7. Determine a suitable worm gear diameter.Ħ. A worm gear design with given axis distance is the most frequent task. W t = tangential load on the worm gear (N),Īn outline design procedure for a worm and wheel gear set using the AGMA equations is:ģ. The efficiency, in percent, for worm gearing is given by: N = rotational speed of the worm (rpm), and The sliding velocity at the mean worm diameter can be determined by: Determine the maximum recommended face width, F. Φ n = normal pressure angle of the worm thread at the mean diameter (°) An outline design procedure for a worm and wheel gear set using the AGMA equations is: 1. W t = tangential load on the worm gear tooth (N), Μ = friction, (Based on sliding velocity) Values for the ratio correction factor (C m), the velocity factor (C v), and materials factors ( C s) can be found from tables provided in the ANSI/AGMA 6034-B92 standard ot here:ĪGMA Wormgear Equations For Rating Factors The AGMA tangential load on a worm gear is given by:Ĭ s = materials factor, based on manufacturing process V t = sliding velocity at the mean worm diameter (m/s) P output = ( n W t d g ) / ( 1.91 x 10 6 m G ) Where P loss is the power lost due to friction in the mesh (kW). The input-power rating, P input, is given by: RackPinion.xls: To estimate rack and pinion gear tooth strength (FEA or more detailed analysis required to do a complete design). Preview Wormgear Calculator, torque, output power, power lost, tangential load To estimate gear tooth strength for a worm gear (FEA or more detailed analysis required to do a complete design). Maximum radial deflection of worm gear at pitch point is limited by: The mean worm gear diameter, d m, is within the following limits: The AGMA rating (ANSI/AGMA 6034-B92) is based on 10 h of continuous operation under a uniform load. The AGMA power rating is based on pitting and wear resistance, as this is the usual failure mode for worm sets. Worm gear sets are generally rated by their capacity to handle a particular level of input power, output power, or allowable torque at a particular speed for the input or output shaft. Mechanics and Machine Design and EngineeringĪGMA Worm and Spur Gear Design Equations and Calculators Related Resources: calculators AGMA Worm and Spur Gear Design Equations and Calculators