ENGRANAJES. RUEDAS RECTAS ENGRANAJE RECTO Valores Caracteristicos:  Número de dientes, z  Módulo, m en mm  Paso=  m.

Presentación del tema: "ENGRANAJES. RUEDAS RECTAS ENGRANAJE RECTO Valores Caracteristicos:  Número de dientes, z  Módulo, m en mm  Paso=  m."— Transcripción de la presentación:

1 ENGRANAJES

2 RUEDAS RECTAS ENGRANAJE RECTO Valores Caracteristicos:  Número de dientes, z  Módulo, m en mm  Paso=  m

3 NOMENCLATURA DIMENSIONES: Diámetro medio: D= m z Diámetro de cabeza:D= m (z+2) Diámetro de fondo:D= m (z-2,5)

4 RUEDAS RECTAS ENGRANAJE RECTO

5 Geometría de las ruedas rectas

6 RUEDAS RECTAS FUERZAS GENERADAS Fuerza Tangencial: Ft = Mt / R Fuerza Radial: Fr = Ft Tg  , ángulo de contacto. Valor habitual,  =20º

7 Diámetro medio: D= m a z Diámetro de cabeza:D= m a (z+2) Diámetro de fondo:D= m a (z-2,5) DIMENSIONES: Valores Caracteristicos:  Número de dientes, z  Módulo, m en mm  Paso=  m   a, ángulo de hélice. Valores habituales de 15º 20º RUEDAS HELICOIDALES Módulo aparente: m a = m / cos  a

8 RUEDAS HELICOIDALES FUERZAS GENERADAS Fuerza Tangencial: Ft = Mt / R a Fuerza Radial: Fr = Ft Tg  a Tg  a = Tg  / Cos  a Fuerza axial: Fr = Ft Tg  a

9 RUEDAS CONICAS Valores Caracteristicos:  Número de dientes, z  Módulo, m medio en mm  Paso=  m  1 -  2, ángulos de paso. Ejes perpendiculares:  1 +  2 = 90º Diámetro medio: D= m z Diámetro de cabeza:D= m (z+2) Diámetro de fondo:D= m (z-2,5) DIMENSIONES:

10 RUEDAS CONICAS FUERZAS GENERADAS Fuerza Tangencial: Ft = Mt / R medio Fuerza Radial: Fr = Ft Tg  Cos  Fuerza axial: Fr = Ft Tg  Sen 

11 En la figura se muestra una batidora industrial, en la que podemos ver los diferentes tipos de engranajes. Aplicación de los diferentes tipos de ruedas

12 Engranaje, tornillo sin fín a.) de dientes cilíndricos b.) doble envolvente.

13 Pasos diametrales preferidos Pasos diametrales preferidos para cuatro clases de dientes

14 Pasos diametrales Pasos diametrales estándares comparados con el tamaño del diente. Se supone un tamaño real

15 Addendum, Dedendum and Clearance Table 14.2 Formulas for addendum, dedendum, and clearance (pressure angle 20°, full-depth involute.) Text Reference: Table 14.2, page 623

16 Pitch and Base Circles Figure 14.8 Pitch and base circles for pinion and gear as well as line of action and pressure angle. Text Reference: Figure 14.8, page 624

17 Involute Curve Figure 14.9 Construction of involute curve. Text Reference: Figure 14.9, page 625

18 Contact Ratio Figure 14.10 Illustration of parameters important in defining contact ratio. Text Reference: Figure 14.10, page 629

19 Line of Action Figure 14.11 Details of line of action, showing angles of approach and recess for both pinion and gear. Text Reference: Figure 14.11, page 629

20 Backlash Figure 14.12 Illustration of backlash in gears. Text Reference: Figure 14.12, page 632

21 Recommended Minimum Backlash Table 14.3 Recommended minimum backlash for coarse-pitch gears. Text Reference: Table 14.3, page 633

22 Externally Meshing Spur Gears Text Reference: Figure 14.13, page 635 Figure 14.13 Externally meshing spur gears.

23 Internally Meshing Spur Gears Figure 14.14 Internally meshing spur gears. Text Reference: Figure 14.14, page 635

24 Simple Gear Train Figure 14.15 Simple gear train. Text Reference: Figure 14.15, page 636

25 Compound Gear Train Figure 14.16 Compound gear train. Text Reference: Figure 14.16, page 636

26 Example 14.7 Figure 14.17 Gear train used in Example 14.7. Text Reference: Figure 14.17, page 637

27 Allowable Bending Stress vs. Brinell Hardness Figure 14.18 Effect of Brinell hardness on allowable bending stress for two grades of through-hardened steel [ANSI/AGMA Standard 1012- F90, Gear Nomenclature, Definition of Terms with Symbols, American Gear Manufacturing Association, 1990.] Text Reference: Figure 14.18, page 638

28 Contact Stress vs. Brinell Hardness Figure 14.19 Effect of Brinell Hardness on allowable contact stress for two grades of through-hardened steel. [ANSI/AGMA Standard 1012-F90, Gear Nomenclature, Definition of Terms with Symbols, American Gear Manufacturing Association, 1990.] Text Reference: Figure 14.19, page 639

29 Forces on Gear Tooth Figure 14.20 Forces acting on individual gear tooth. Text Reference: Figure 14.20, page 640

30 Bending Stresses Figure 14.21 Forces and length dimensions used in determining bending tooth stresses. (a) Tooth; (b) cantilevered beam. Text Reference: Figure 14.20, page 641

31 Lewis Form Factors Table 14.4 Lewis form factors for various numbers of teeth (pressure angle 20°, full depth involute). Text Reference: Table 14.4, page 642

32 Spur Gear Geometry Factors Figure 14.22 Spur gear geometry factors for pressure angle of 20° and full- depth involute. [ANSI/AGMA Standard 1012-F90, Gear Nomenclature, Definition of Terms with Symbols, American Gear Manufacturing Association, 1990.] Text Reference: Figure 14.21, page 643

33 Application Factor Table 14.5 Application factor as a function of driving power source and driven machine. Text Reference: Table 14.5, page 643

34 Size Factor Table 14.6 Size factor as a function of diametral pitch or module. Text Reference: Table 14.6, page 644

35 Load Distribution Factor Figure 14.23 Load distribution factor as function of face width and ratio of face width to pitch diameters. Commercial quality gears assumed. [From Mott (1992).] Text Reference: Figure 14.23, page 645

36 Dynamic Factor Text Reference: Figure 14.24, page 645 Figure 14.24 Dynamic factor as function of pitch-line velocity and transmission accuracy level number.

37 Helical Gear Figure 14.25 Helical gear. (a) Front view; (b) side view. Text Reference: Figure 14.25, page 651

38 Pitches of Helical Gears Figure 14.26 Pitches of helical gears. (a) Circular; (b) axial. Text Reference: Figure 14.26, page 652

39 Motor Torque and Speed Figure 14.28 Torque and speed of motor as function of current for industrial mixer used in case study. Text Reference: Figure 14.28, page 655