Screw Gears Used for Non-Intersecting Shafts
Screw gears, also sometimes called crossed helical gears, are helical gears used in motion transmission between non-intersecting shafts. The helical gears used in parallel shafts have the same helix angle but in the opposite directions. For shaft angles other than parallel, an arbitrary helix angle can be chosen, and, assuming no profile shift, the intersecting angle of the shafts is the sum of the respective helix angles. Helical gears have point contacts and have lower efficiency than parallel or perpendicular shaft gears and cannot transmit heavy loads.
Also, if the same material is used in screw gears, it could lead to friction and galling. Therefore, KHK recommends the use of different materials in a pair. Besides, unlike bevel gears, there are no restrictions on the numbers of teeth combinations and the speed transmission ratio becomes the number of teeth of the driving gear divided by the number of teeth of the driven gear. Please consult the “Gear Applications” pages for the actual working of screw gears.
Related links :
Technical Information of Screw Gears
Helical Gears– Main page of helical gears
Equivalent tables of each standard relating to raw materials and precision grades of gears
Plastic Gears– A page of plastic gears
交错轴斜齿轮 (螺旋齿轮) – 中文页
SN
Steel Screw Gears
Module : 1 – 4
Material : S45C
Hardening : None
Tooth finish : Cut (non-ground)
Grade : JIS N9
General purpose screw gear. Only the tooth surfaces are induction hardened, allowing secondary operations.
SUN
Stainless Steel Screw Gears
Module : 1 – 3
Material : SUS303
Hardening : None
Tooth finish : Cut (non-ground)
Grade : JIS N9
Made of SUS303 material, its rust resistant characteristics is most suitable for food machinery.
AN
Aluminum Bronze Screw Gears
Module : 1 – 4
Material : CAC702 (AlBC2)
Hardening : None
Tooth finish : Cut (non-ground)
Grade : JIS N9
Using aluminum bronze gives superior anti-friction quality.
PN
Plastic Screw Gears
Module : 1.5 – 3
Material : MC901
Hardening : None
Tooth finish : Cut (non-ground)
Grade : JIS N9
Lightweight products made with MC Nylon, possible to use without lubrication.