《MARINE GEARS》

INTRODUCTION13

Chapter Ⅰ:DESIGN A. DESCRIPTIONS19

1Introduction19

2 Actual designs21

3 A.E.G.marine gears24

4 Ansaldo marine gears24

5 British Thomson-Houston marine gears31

6 Wm.Denny ＆ Bros.,Ltd.marine gears33

7 Howaldt-werke marine gears35

8 De Laval Marine Gears37

9 M.A.A.G.marine gears39

10 Parsons marine gears46

11 De Schelde marine gears46

12 Westinghouse Electric Corp.marine gears46

13 (Zrodowski’s) General Electric marine gears46

References49

Chapter Ⅱ:DESIGN CLASSIFICATION RULES50

A.COMPARISON OF SOME PRIMARY DESIGN RULES FOR MARINE GEARS50

14Introduction50

15 Germanischer Lloyd50

16 Lloyd’s Register of Shipping52

17 Bureau V？ritas54

18 Zrodowski’s unit load57

19 Blok’s permissible flash temperature59

20 Bending stresses59

21 Application to and further investigations of specific designs60

22 Double helical,hobbed design60

23 Hardened and ground gear64

References65

B.ADDITIONAL CONSIDERATIONS WITH RESPECT TO PRIMARY DESIGN RULES66

24Pinion deformation66

25 Pinion deformation with regard to bearing clearance70

26 Maximum tooth opening with regard to oil-film thickness in meshing zone71

27 Pinion deformation with regard to local tooth overloading73

28 Natural (or free) torsional vibrations of pinions73

References74

C.ACTUAL RULES OF THE VARIOUS SOCIETIES74

29American Bureau of Shipping74

30 Bureau Véritas74

31 Germanischer Lloyd83

32 Lloyd’s Register of Shipping93

Appendix99

Chapter Ⅲ:DESIGN-CALCULATIONS101

33Introduction101

A.DEFORMATIONS AND STRESS SYSTEMS IN WHEEL TYRES AND WHEEL RIMS101

34Introduction101

35 Deformations and stresses in the wheel tyre and wheel rim of a wheel with shrunk-on wheel tyre - same modulus of elasticity throughout the wheel101

36 First primary stress system103

37 Second primary stress system103

38 Transitional stress systems103

39 Division made in the investigation of tran-sitional stresses105

40 Transitional stress systems for a design consisting of two infinitely (very) long wheel tyres and wheel rims on either side of a wheel center disc105

41 Investigation into the nature of the con-tact between wheel tyre and wheel rim109

42 Transitional stress systems for a structure with infinitely (very) long wheel tyre and wheel rim on one side of the wheel center disc only111

43 Verifying the moment of wheel center disc to wheel rim113

44 Stability of wheel center disc and wheel rim114

45 Angular rotation in the K1 system; tran-sition moment to wheel center disc114

46 Investigation into the behaviour of the wheel tyre and the wheel rim in the K1-and K2-systems115

47 Transition stress systems in the case of a short wheel tyre and wheel rim on one side of the wheel center disc (with finite overhang)and infinitely (very long) ones on the other side116

48 Transition stress systems for a design with- out overhang or with a short overhang on one side of the wheel center disc, and with a finite (short) wheel tyre and wheel rim on the other side respectively118

49 Summary120

50 Deformations and stress systems in the wheel tyre and wheel rim of a wheel with shrunk-on wheel tyre,when the moduli of elasticity of wheel tyre and wheel rim are essentially different121

51 Secondary stress systems121

52 Summary123

B.POSSIBLE LOADS ON A SPLIT MAIN WHEEL OF A MARINE GEAR123

C.WHEEL DESIGN123

53General discussion123

54 Some actual designs125

References129

D.ANALYSIS OF THE DESIGN OF CARBURIZED, HARDENED AND GROUND PINIONS IN RELATION TO THE HEAT TREATMENT129

55Introduction129

56 Form factor of pinions129

57 Experiments with ECN 35130

58 Elastic tooth stresses and K-factor133

59 Testing of material134

References135

Appendix135

60 Hardenability tests Taken Up in Soviet Paper135

E.TOOTH STRESS CALCULATIONS135

61Introduction135

62 Calculation of nominal bending fatigue stresses in gear teeth136

63 W. John Davies’ fatigue formulae for gears138

64 Jacobson’s photo-elastic research on spur gears139

65 Bending fatigue stress calculations ac-cording to A.V.G.R.A139

66 Braley and Berg’s (US Navy) stress para-meters compilations141

67 Zrodowski’s Unit Load143

References144

F.DYNAMIC LOADS IN MARINE GEARS144

68Introduction144

69 British Thomson Houston investigations on dynamic loads145

70 Dynamic loads on spur gears147

71 Dynamic loads in single, or double, helical marine gears of appreciable helix angle148

References152

G.TEMPERATURE LOADS IN MARI-NE GEARS153

72Introduction153

73 Wydler’s non-dimensional determination of Hertz stress, sliding load and scoring factor154

74 Blok’s flash temperature criterion158

75 Blok’s flash temperature criterion for single or double helical marine gears with ap-preciable helix angle160

76 Applicability of the flash temperature for-mula to full hydrodynamic conditions162

77 Further discussion of flash temperature cri-terion for single or double helical marine gears of appreciable helix angle164

78 Rolling and sliding velocities in gear tooth action167

79 W.John Davies’scuffing criterion169

80 Effect on tooth contact of differential heating between pinion and wheel169

References171

H.WEIGHT OF MARINE GEARS171

81Introduction171

82 Deriving parameters as bases of discussion for marine gear weight173

83 Bending stress-torque-modulus parameter175

84 Other stress parameters175

85 Machining costs176

86 Casing design177

References177

Chapter Ⅳ:COUPLINGS178

87Introduction178

A.FINE TOOTHED COUPLINGS178

88Introduction178

Reference180

B.DESIGN CALCULATION OF A FLEXIBLE COUPLING180

89Introduction180

90 Flexible coupling180

91 Elastic stresses181

92 Light loads181

93 Possible vibrations of the flexible coupling183

94 Normal loads183

95 Loads with racing coupling185

96 Thomassen’s type of coupling185

97 Flexible coupling between propeller and reduction gearing186

C.MALMEDY-BIBBY COUPLINGS187

98Flexible coupling of the Malmédy-Bibby type187

Reference188

D.FALK-BIBBY COUPLINGS188

99Flexible coupling of the Falk,,steelflex” type188

E.RENK COUPLINGS194

100Resilient bush couplings194

Reference195

F.REVERSIBLE FLUID COUPLING FOR GAS-TURBINE-DRIVEN MA-RINE PROPULSION UNIT,IN-CORPORATED IN MARINE GEAR196

FⅠ.Part played by the coupling as a unit of the main propulsion installation196

101Introduction196

102 Parnetrada’s hydraulic reversible coupling196

103 Reversing system with a fluid coupling(and friction coupling for cruising)198

104 Heat to be removed in coupling oil199

105 Losses sustained in manoeuvring with single fluid coupling with intermediate blades199

106 Gas coupling199

107 Dynamic phenomena200

108 Torsional vibrations of the first-reduction pinion200

109 Quill shafts201

110 Torsional vibrations of the system gas tur-bine-reduction gear-propeller, with or without turbine201

111 Hardened and ground gears201

112 Hobbed gears201

113 Retardations (and accelerations) during manoeuvring202

114 Dynamic phenomena due to pitch errors204

References204

FⅡ.Dimensioning, damping, control205

115Introduction205

116 Dimensional analysis of a fluid coupling205

117 Transmission efficiency as a function of the weight of the fluid206

118 Investigation into the regulation of the quantity206

119 Oil drain from the coupling208

120 Restricting manoeuvring time208

121 Hydrodynamic accelerations and retar-dations in the coupling209

122 Regulation with baffles209

References209

G.BARCLAY-CURLE HYDRAULIC COUPLINGS210

123Barclay-Curle hydraulic couplings210

Reference210

H.VULKAN COMPRESSED AIR COUPLINGS211

124Vulkan compressed air coupling211

I.TORSIONAL FREQUENCIES IN SINGLE GAS-TURBINE-DRIVEN, LOCKED TRAIN MARINE GEAR-MARINE PROPELLER, PROPULSION UNIT213

125Introduction213

126 Main part？culars213

127 Distribution of mass moments of inertia214

128 Reduced shaft lengths214

129 Mass moments of inertia,resp.shaft lengths reduced on propeltershaft214

130 System reduced on propeller speed214

131 Critical frequency of the first order214

132 Critical frequency of the second order215

133 Critical frequency of the third order216

134 Critical frequencies of the first order for different turbine rotor mass moments of inertia216

135 Hardened and ground gear216

References216

J.TORSIONAL FREQUENCY CALCU-LATION OF AN ACTUAL DESIGN216

136Torsional frequency calculation of R ＆ W.Hawthorn Leslie ＆ Co.,Ltd.’s 7.500/8,250 hp at 100/103 r.p.m. design216

Appendix218

Chapter Ⅴ: BEARINGS219

A.BALL AND ROLLER BEARINGS219

137Introduction219

138 Ball and roller bearings220

B.SLEEVE BEARINGS222

139Description222

140 Design calculation223

141 Oil whirl in bearings229

C.THRUST BEARINGS231

142Thrust bearings231

D.FLEXIBLE COUPLINGS231

143Lubrication of flexible couplings231

E.OIL FILM THICKNESS IN SPUR GEAR TEETH232

144Oil film thickness in the contact area of loaded and running straight spur gear teeth232

F.LUBRICATING OIL234

145Lubricating oil for turbine marine propul-sion units234

146 Extreme pressure lubricants for marine gears236

147 Gas-lubricated bearings241

AppendixⅠ242

AppendixⅡ243

References247

Chapter Ⅵ: MATERIALS248

148Introduction248

A.MATERIAL SPECIFICATIONS248

149Material specifications248

B.MATERIAL FAILURES250

150Material failures250

151 New reagent for microscopic strain analysis in steel254

C.SPHERICAL INCLUSIONS IN STEEL255

152The identification of microscopic spherical inclusions in electric-furnace steel255

153 Conclusion257

D.STRESS SYSTEMS CAUSED THROUGH DIFFUSION IN MATERIALS257

154Summary257

155 Diffusion257

156 Crystalline boundary diffusion258

157 Spherical diffusion258

158 Stress system259

159 Differential equation for the geometricai displacerhent parameter259

160 Study of stresses260

161 Rupture conditions-critical hole radius260

162 Time elapsed at rupture - characteristic time261

163 Fatigue stresses262

164 Actual failures263

165 Rupture not adjacent to the load263

166 Conclusions263

Appendix263

167 Dislocations263

168 Crystal forming during casting264

References264

Chapter Ⅶ:MANUFACTURE265

169Introduction265

A.GENERAL DESCRIPTIONS OF REDUCTION GEAR FACTORIES265

170Stabilimente Meccanico Ansaldo, Genoa265

171 Royal Shipbuilding and Engineering Co.De Schelde,Flushing266

172 Schiess AG,Duesseldorf271

References275

B.TOOTH GENERATING MACHINES275

173Introduction275

174 Development of hobbing machines281

175 Developing, and measuring, accuracy of bobbing machines and gears286

176 The application of hydrostatic high pre-cision bearings to gear bobbing machines,resp.marine reduction gears293

177 Horizontal hobbing297

178 Hobbing by a diagonal generating process299

179 Gear cutting and gear grinding machines299

References301

C.MACHINING PROCESSES301

180Introduction301

181 Hobbing303

182 ,,R？umwalzfr？ser”;hobsforroughhobbing309

183 Hob tooth profiles315

184 Hobbing energy317

185 New developments in hobbing317

186 Post-hobbing processes321

187 Shaping and grinding323

188 Machining operations, not connected with gear generation324

189 Assembly325

References325

D.HEAT TREATMENT325

190Introduction325

191 De Schelde gas carburizing and hardening plant326

192 AVGRA gas carburizing and hardening plant328

193 Induction hardening331

194 Case thickness and hardness gradients331

References332

E.MEASUREMENTS332

195Introduction332

196 Roughness measurements on marine gear teeth335

197 Tooth surface roughness, measured on large gear wheels335

198Comparison of the Talysurf apparatus with the interference microscope for the mea-surement of surface roughness339

Summary343

199 Other roughness records of hobbed (and shaved) gear teeth343

200 Gear tooth undulations343

201 Checking the heat treatment of hardened and ground gears352

202 Checking macroscopic tooth geometry353

203 Dynamic loads, and pitch errors357

204 Checking geometry of the gearing359

205 The alignment of gear cases in manufacture and on board360

References361

Chapter Ⅷ:RESEARCH AND TES-TING OF MARINE GEARS362

A.STATISTICAL ANALYSIS362

206Introduction362

207 Statistical analysis of marine gear failures362

208 Pitting363

209 Scuffing of teeth373

210 Tooth fracture375

211 Wheel failures375

B.RESEARCH ON ULTIMATE LOADS378

212Introduction378

213 Measurement of the machining stresses in gear teeth378

214 Gear and casing deformation under load379

215 Actual tests of gears and casing under load381

216 Wheel deformation383

217 Possible surface and bending fatigue stresses383

References389

C.VIBRATION AND NOISE RESEARCH390

218Vibration and sound research in relation to the cutting machine390

Reference395

D.CRITICAL TORSIONAL SPEEDS OF PINIONS396

219Introduction396

220 Natural torsional vibrations of a cylindrical bar,as derived by the “eigenvalues” method396

221 Critical torsional speeds of pinions in ma-rine gears400

Reference401

E.VIBRATIONS OF NESTED TYPES OF GEARS401

222Introduction401

223 Propeller torque401

224 Differences in magnitude and character of cyclic pitch error on both helices of wheel, resp. pinion403

225 Displacement of the intermeshing teeth on main wheel due to elastic behaviour of parts of the gear403

226 Natural torsional vibrations of wheel helices405

227 Forced torsional vibrations of wheel helices405

228 Absorbing pitch errors on the meshing teeth only405

229 Natural and forced bending vibrations in main wheel406

230 Integral first reduction design406

231 Summary406

References406

F.SOUND PRODUCTION AND VI-BRATIONS IN MARINE GEARS-ANALYSIS OF PROPULSION SYS-TEMS406

232Sound production and vibrations in marine gears, analysis of propulsion systems406

References412

G.SHOP AND SHIP TRIALS412

233Introduction412

234 Problems of running-in of marine gears418

235 Shop and ship trials on naval gears426

References427

H.PRESERVATION OF MARINE GEARS428

Appendix Ⅰ430

236Heat and mass transfer on the surfaces of cold liquids430

Reference431

Appendix Ⅱ431

237The alignment of gear cases in manufac-ture and on board431

Concluding appendix433

References439