Precision grade JIS quality N9 (JIS B1702-1: 1998) JIS quality 5 (JIS B1702: 1976)
portion of gear Normal plane
Gear teeth Standard complete depth
pressure angle 20°
Helix angle 45°
① When mating screw gears made of the same material they may trigger Aluminum-Bronze Screw Gears abrasion and scoring. It is suggested to mate Screw Gears made up of different materials.
② The allowable torques shown in the table are the calculated values based on the assumed usage conditions.
③ The backlash values proven in the table are the theoretical values for the backlash in the standard direction of a pair ofidentical gears in mesh.
④ For offset shaft applications, match a RH with a RH, or LH with a LH, to produce a set of screw gears. For parallel shaft applications,
mesh opposite hands (RH and LH) of helical gear sets.
⑤ If the bore diameter is usually less than φ 4, then the bore tolerance class is usually H8. If the bore diameter is usually φ 5 or φ 6, and the hole length (total duration) exceeds 3 times the diameter, then the class can be H8.