To provide a helical gear which is small in a deformation amount before and after a gear rotation test, and can reduce an increase of a sound accompanied by the gear rotation test.
In a helical gear comprising a plurality of ribs having penetration holes which are formed in centers and teeth formed at external peripheries, and radially arranged in directions toward the external peripheries from the penetration holes, and flat-plate shaped webs arranged between the plurality of ribs, the helical gear is a molded body of a polyacetal resin composition which contains a polyacetal resin and whose tensile elasticity is 3,500 to 7,000 Mpa, a twisted angle is 5 to 30°, a tooth width is 1 to 20 mm, the thickness of the web is 1.5 to 6 mm, and the number of the ribs is 6 to 24.
CHAYAGAITO RYOICHI
| JP2002235835A | 2002-08-23 | |||
| JP2000346176A | 2000-12-12 | |||
| JP2007298157A | 2007-11-15 |
| WO2007010917A1 | 2007-01-25 |
Toshifumi Onuki
Kazuhiko Naito