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barcode generator vb.net code WORM GEARING 12.5 in Software
WORM GEARING 12.5 Decoding EAN13 In None Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications. Encoding EAN13 In None Using Barcode creation for Software Control to generate, create EAN13 image in Software applications. WORM GEARING
European Article Number 13 Reader In None Using Barcode decoder for Software Control to read, scan read, scan image in Software applications. Create GTIN  13 In C# Using Barcode generator for .NET framework Control to generate, create EAN13 Supplement 5 image in .NET applications. 12.3 VELOCITY AND FRICTION
EAN13 Creator In VS .NET Using Barcode drawer for ASP.NET Control to generate, create European Article Number 13 image in ASP.NET applications. Generating EAN13 In .NET Framework Using Barcode maker for .NET framework Control to generate, create GS1  13 image in VS .NET applications. Figure 12.4 shows the pitch line velocities of worm and gear. The coefficient of friction between the teeth is dependent on the sliding velocity. Representative values of are charted in Fig. 12.5. The friction has importance in computing the gear set efficiency, as will be shown. Making EAN13 Supplement 5 In VB.NET Using Barcode generator for Visual Studio .NET Control to generate, create UPC  13 image in VS .NET applications. UCC  12 Encoder In None Using Barcode creator for Software Control to generate, create UPCA Supplement 2 image in Software applications. 12.4 FORCE ANALYSIS
Bar Code Drawer In None Using Barcode creator for Software Control to generate, create barcode image in Software applications. Make Data Matrix 2d Barcode In None Using Barcode generation for Software Control to generate, create Data Matrix image in Software applications. If friction is neglected, then the only force exerted by the gear on the worm will be W, perpendicular to the mating tooth surface, shown in Fig. 12.6, and having the three components Wx, Wy, and Wz. From the geometry of the figure, Wx = W cos n sin Wy = W sin n W = W cos n cos Code 39 Printer In None Using Barcode encoder for Software Control to generate, create Code 3 of 9 image in Software applications. Generating UPC  13 In None Using Barcode creation for Software Control to generate, create EAN13 image in Software applications. (12.10) Draw Identcode In None Using Barcode printer for Software Control to generate, create Identcode image in Software applications. UPCA Drawer In Java Using Barcode drawer for Java Control to generate, create UPC Symbol image in Java applications. In what follows, the subscripts W and G refer to forces on the worm and the gear. The component Wy is the separating, or radial, force for both worm and gear (opposite in direction for the gear). The tangential force is Wx on the worm and Wz on the gear.The axial force is Wz on the worm and Wx on the gear.The gear forces are opposite to the worm forces: WWt = WGa = Wx WWr = WGr = Wy WWa = WGt = Wz (12.11) Scanning Barcode In Java Using Barcode decoder for Java Control to read, scan read, scan image in Java applications. Make GS1128 In None Using Barcode generation for Online Control to generate, create GS1128 image in Online applications. FIGURE 12.4 Velocity components in a wormgear set. The sliding velocity is VS = VW 2 2 . (V W + V G )1/2 = cos Make Code 128 In VS .NET Using Barcode creator for ASP.NET Control to generate, create Code 128 Code Set B image in ASP.NET applications. Scanning GS1128 In Visual Basic .NET Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications. Downloaded from Digital Engineering Library @ McGrawHill (www.digitalengineeringlibrary.com) Copyright 2004 The McGrawHill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Printing ANSI/AIM Code 39 In None Using Barcode drawer for Microsoft Excel Control to generate, create Code 3 of 9 image in Excel applications. 1D Barcode Generation In Visual Basic .NET Using Barcode generator for Visual Studio .NET Control to generate, create Linear 1D Barcode image in .NET applications. WORM GEARING 12.6
GEARING
FIGURE 12.5 Approximate coefficients of sliding friction between the worm and gear teeth as a function of the sliding velocity. All values are based on adequate lubrication. The lower curve represents the limit for the very best materials, such as a hardened worm meshing with a bronze gear. Use the upper curve if moderate friction is expected. FIGURE 12.6 Forces exerted on worm.
Downloaded from Digital Engineering Library @ McGrawHill (www.digitalengineeringlibrary.com) Copyright 2004 The McGrawHill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. WORM GEARING 12.7
WORM GEARING
where the subscripts are t for the tangential direction, r for the radial direction, and a for the axial direction. It is worth noting in the above equations that the gear axis is parallel to the x axis and the worm axis is parallel to the z axis. The coordinate system is righthanded. The force W, which is normal to the profile of the mating teeth, produces a frictional force Wf = W, shown in Fig. 12.6, along with its components W cos in the negative x direction and W sin in the positive z direction. Adding these to the force components developed in Eqs. (12.10) yields Wx = W(cos n sin + cos ) Wy = W sin n Wz = W(cos n cos sin ) Equations (12.11) still apply. Substituting Wz from Eq. (12.12) into the third of Eqs. (12.11) and multiplying by , we find the frictional force to be Wf = W = WGt sin cos n cos (12.13) (12.12) A relation between the two tangential forces is obtained from the first and third of Eqs. (12.11) with appropriate substitutions from Eqs. (12.12): WWt = WGt The efficiency can be defined as = WWt (without friction) WWt (with friction) (12.15) cos n sin + cos sin cos n cos (12.14) Since the numerator of this equation is the same as Eq. (12.14) with = 0, we have = cos n tan cos n + cot (12.16) Table 12.1 shows how varies with , based on a typical value of friction = 0.05 and the pressure angles usually used for the ranges of indicated. It is clear that small should be avoided. Example 1. A 2tooth righthand worm transmits 1 horsepower (hp) at 1200 revolutions per minute (r/min) to a 30tooth gear. The gear has a transverse diametral pitch of 6 teeth per inch. The worm has a pitch diameter of 2 inches (in). The normal pressure angle is 141 2 . The materials and workmanship correspond to the lower of the curves in Fig. 12.5. Required are the axial pitch, center distance, lead, lead angle, and tooth forces. Solution. The axial pitch is the same as the transverse circular pitch of the gear. Thus px = = = 0.5236 in P 6 Downloaded from Digital Engineering Library @ McGrawHill (www.digitalengineeringlibrary.com) Copyright 2004 The McGrawHill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.

