Date post: | 06-Apr-2018 |
Category: |
Documents |
Upload: | vijaykumarn |
View: | 222 times |
Download: | 0 times |
8/2/2019 Spiral Bevel Assy
http://slidepdf.com/reader/full/spiral-bevel-assy 1/3
8/2/2019 Spiral Bevel Assy
http://slidepdf.com/reader/full/spiral-bevel-assy 2/3
8/2/2019 Spiral Bevel Assy
http://slidepdf.com/reader/full/spiral-bevel-assy 3/3
Verifying properassembly. Use themeasurementmethod to assemble both gears, making
sure that the matched teeth are properly engaged. Only after positioning both
gears at their mounting distances should
you measure backlash to verify proper as-sembly. In cases where only the pinion is
marked with a mounting distance, posi-tion the pinion at its mounting distancefirst, then adjust the gear position for therequired backlash.
To obtain further verification, you canperform an optional contact patterncheck. This involves painting the toothsurfaces on one gear with a thin markingcompound and rotating the assembledgears under light load. The c ompoundtransfers from one gear to the other and
shows how the teeth contact. Numerouspublications contain charts with typicalcontact patterns (ANSI/AGMA 2008-B90and ANSI/AGMA 2005-B88). The patternsseldom look exactly like the published ex-amples and frequently require some in-terpretation.
Technicians familiar with contact pat-tern checking may believe that this tech-nique is the preferred method of assem-bly. However, the manufacturer hasalready performed this check as part of
the testing (to determine mounting di-mensions) and interpreted the contactpatterns so you don’t have to.s
Figure 4 — Measurementsrequired for mounting bothoverhung and straddle-mountedbevel gears in a typicalgearbox.
POWER TRANSMISSION DESIGN s MARCH 1994 53
Backlashmeasurement
Normalbacklash
Top view of teeth
Tooth outer end
Pitch circle
Figure 3 — Normalbacklash in a set of
spiral bevel gears ismeasured perpen-dicular to the toothsurface at the outer
end (heel) of thetooth, using a
dial gage.
Straddle mountedgear subassembly
Assembled gearbox
Overhung mountedpinion subassembly
Shim thickness= MDV – VMD
Shim thickness= MDH – HMD
Housing
HMD
VMD
MDV
MAP
WP
MAG
MDG
WG
MDP
MDH
MDH =
MDV =MD
G– W
G+ MA
G
MDP – WP + MAP