DESIGN OF PLASTIC GEARS - Quality Transmission Components - #15

/ 15


catalogue search
P. 01
P. 02
P. 03
P. 04
P. 05
P. 06
P. 07
P. 08
P. 09
P. 10
P. 11
P. 12
P. 13
P. 14
P. 15
Pages:


See other catalogues for Quality Transmission Components
You may also be interested in

Gear, Helical gear, Planetary gearbox, Tensioner, Gear reducer


Text version of the page
(a) Mold Closed
(b) Mold Open (c) Part, Runners &
Sprue Ejected
Fig. 18-15 Two-Plate Mold
SECTION 19 FEATURES OF TOOTH SURFACE CONTACT
Tooth surface contact is critical to noise, vibration, efficiency, strength, wear and life. To obtain good contact, the designer must give proper consideration to the following features:
- Modifying the Tooth Shape
Improve tooth contact by crowning or relieving.
- Using Higher Precision Gear
Specify higher accuracy by design. Also, specify that the manufacturing process is to include grinding or lapping.
- Controlling the Accuracy of the Gear Assembly
Specify adequate shaft parallelism and perpendicularity of the gear housing (box or structure). Surface contact quality of spur and helical gears can be reasonably controlled and verified through piece part inspection. However, for the most part, bevel and worm gears cannot be equally well inspected. Consequently, final inspection of bevel and worm mesh tooth contact in assembly provides a quality criterion for control. Then, as required, gears can be axially adjusted to achieve desired contact.
JIS B 1741 classifies surface contact into three levels, as presented in
Table 19-1.
The percentage in Table 19-1 considers only the effective width and height of teeth.
Table 19-1 Levels of Gear Surface Contact
Level
Types of Gear
Levels of Surface Contact
Tooth Width Direction
Tooth Height Direction
A
Cylindrical Gears
More than 70%
More than 40%
Bevel Gears
More than 50%
Worm Gears
B
Cylindrical Gears
More than 50%
More than 30%
Bevel Gears
More than 35%
Worm Gears
C
Cylindrical Gears
More than 35%
More than 20%
Bevel Gears
More than 25%
Worm Gears
More than 20%

pageCatalog pdf di En 2012-05-22-31