Worm Gears Formulas
Worm Gears
12/17/10 12/17-12:19AM
Disclaimer: The information on this page has not been checked by an independent person. Use this information at your own risk.
ROYMECH
Aamco Transmissions Local Independent Nationwide warr. 802-864-0049 Free Estimates www.aamco.com/centerinfo.asp
Right Angle Gearbox Spiral Bevel, Helical Bevel, Worm for PT & Motion Control, 1-50 HP www.diequa.com
Nordex OnLine Catalog Thousands of Components In Stock Ready to Ship www.nordex.com
Home
Drive_Index
Gears Gearboxes
Worm Gears
Introduction..... Nomenclature..... Design Parameters..... Specifications..... Designation..... Worm Gear Profiles..... Materials.....
Design Process..... Thermal Design..... Worm Gear Formulue..... Friction Factors..... Strength Design to BS721..... Strength Design to
AGMA.....
Introduction
A worm gear is used when a large speed reduction ratio is required between crossed axis shafts which do not intersect. A basic helical gear can be used but the power which can be transmitted is low. A worm drive consists of a large diameter worm wheel with a worm screw meshing with teeth on the periphery of the worm wheel. The worm is similar to a screw and the worm wheel is similar to a section of a nut. As the worm is rotated the wormwheel is caused to rotate due to the screw like action of the worm. The size of the worm gearset is generally based on the centre distance between the worm and the wormwheel.
If the worm gears are machined basically as crossed helical gears the result is a highly stress point contact gear. However normally the wormwheel is cut with a concave as opposed to a straight width. This is called a single envelope worm gearset. If the worm is machined with a concave profile to effectively wrap around the wormwheel the gearset is called a double enveloping worm gearset and has the highest power capacity for the size. Single enveloping gearsets require accurate alignment of the worm-wheel to ensure full line tooth contact.
12/17/10 12/17-12:19AM
Disclaimer: The information on this page has not been checked by an independent person. Use this information at your own risk.
ROYMECH
Aamco Transmissions Local Independent Nationwide warr. 802-864-0049 Free Estimates www.aamco.com/centerinfo.asp
Right Angle Gearbox Spiral Bevel, Helical Bevel, Worm for PT & Motion Control, 1-50 HP www.diequa.com
Nordex OnLine Catalog Thousands of Components In Stock Ready to Ship www.nordex.com
Home
Drive_Index
Gears Gearboxes
Worm Gears
Introduction..... Nomenclature..... Design Parameters..... Specifications..... Designation..... Worm Gear Profiles..... Materials.....
Design Process..... Thermal Design..... Worm Gear Formulue..... Friction Factors..... Strength Design to BS721..... Strength Design to
AGMA.....
Introduction
A worm gear is used when a large speed reduction ratio is required between crossed axis shafts which do not intersect. A basic helical gear can be used but the power which can be transmitted is low. A worm drive consists of a large diameter worm wheel with a worm screw meshing with teeth on the periphery of the worm wheel. The worm is similar to a screw and the worm wheel is similar to a section of a nut. As the worm is rotated the wormwheel is caused to rotate due to the screw like action of the worm. The size of the worm gearset is generally based on the centre distance between the worm and the wormwheel.
If the worm gears are machined basically as crossed helical gears the result is a highly stress point contact gear. However normally the wormwheel is cut with a concave as opposed to a straight width. This is called a single envelope worm gearset. If the worm is machined with a concave profile to effectively wrap around the wormwheel the gearset is called a double enveloping worm gearset and has the highest power capacity for the size. Single enveloping gearsets require accurate alignment of the worm-wheel to ensure full line tooth contact.