Page 301 - Analysis and Design of Machine Elements
P. 301

Steps         Computation                                   Results  Shafts  279
                                                                                                    Units
                                         Shaft segment II:                             d = 58       mm
                                                                                        II
                                         To meet the requirement of axial location of the half  L = 50  mm
                                                                                        II
                                         coupling, the right side of shaft segment I needs a shoulder
                                         with a height of approximate h = (0.07∼0.1) d. Therefore, the
                                         diameter of segment II is d = 58 mm.
                                                            II
                                         The total width of the bearing cover is 20 mm by structural
                                         design. According to the requirement of assembly and
                                         disassembly of the bearing cover to facilitate grease addition
                                         for the left bearing, select L = 50 mm.
                                                            II
                                         Shaft segment III:                            d  = 65      mm
                                                                                        III
                                         According to d = 58 mm, a pair of angular contact ball  L III  = 33  mm
                                                    II
                                         bearing 7313C is tentatively selected to carry both radial and
                                         axial forces, with dimensions of
                                         d × D × T = 65 mm × 140 mm × 33 mm [12]. Therefore,
                                         d III  = d VII  = 65 mm, L III  = 33 mm.
                                         Shaft segment VI:                             d VI  = 70   mm
                                         Select thediameterofthe shaftmatingwiththe gear as  L VI  = 48  mm
                                         d  = 70 mm. A spacer is used between the right side of gear
                                          VI
                                         and the right bearing. Since the width of the gear hub is
                                         B = 50 mm, select L  = 48 mm.
                                          2             VI
                                         Shaft segment V:                              d = 80       mm
                                                                                        V
                                         Ashoulderringisusedtolocatethe gear.Theheight of the  L = 10  mm
                                                                                        V
                                         shoulder ring should be h > 0.07d. Therefore, select
                                         h = 5 mm. The diameter of the shoulder ring is d = 80 mm.
                                                                           V
                                         The width of the should ring should be b ≥ 1.4 h,select
                                         L = 10 mm.
                                          V
                                         Shaft segment IV:                             d IV  = 77   mm
                                         A shoulder is used for locating the left bearing axially. The  L IV  = 73  mm
                                         height for the location shoulder for bearing 7313C is
                                         specified by bearing catalogues as 6 mm [12]. Therefore,
                                         d IV  = 77 mm.
                                         Refer to Figure E10.1,
                                         L  = S + A + B + C − L  = 8 +15+40 +20
                                          IV          1       V
                                         − 10 = 73mm
                                         Shaft segment VII:                            d VII  = 65  mm
                                         The right angular contact ball bearing 7313C is mounted on  L VII  = 58  mm
                                         shaft segment VII. Refer to Figure , therefore,
                                         L VII  = T + S + A + B − L VI  = 33+8+15 +50
                                                          2
                                         − 48 = 58mm
                                         Thus, the diameters and lengths of each shaft segment are
                                         tentatively decided.
                                                                                                (continued)
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