can we use the same design calculations for designing a rack and pinion arrangement as we do with the two straight spur gears in mesh
- posted
18 years ago
can we use the same design calculations for designing a rack and pinion arrangement as we do with the two straight spur gears in mesh
Yes.
In fact, standard gear hobbing uses a rack-shaped cutter to machine spur gears. It's the magic of the involute form that any diameter gear (including the infinite-diameter rack) will work.
Hth, Fred Klingener
then how can we calculate number of teeth for rack
as for spur gear number of teeth = diameter/ module
but for rack we have no diameter
A rack is a gear with infinite (arbitrarily large) diameter.
Ned Simmons
Talk about the tooth pitch instead.
Tooth pitch is the developed length between the teeth along the pitch circumference. On a spur (pinion) gear, it's a circular arc. On a rack, it's a straight line.
Spur gear pairs roll on tangent pitch circles. Pitch circle of the pinion rolls on the rack pitck line.
Hth, Fred Klingener
if number of teeth on a spur is pitch diameter/module Then tooth spacing on the pitch circle is pitch circle circumference / number of teeth or pi X D / (D/module) = pi X module. This is evidently the tooth pitch you want on the rack.
Brian Whatcott Altus OK
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.