GEAR

1
GEAR

• Complete all calculations
• Set up AutoCAD title A title block
• Draw Center lines
• Draw the pitch circle, root circle circle,
  addendum circle using the center lines.
• Develop the 14 1/20 pressure angle.
• Draw base circle using center of other circles
  radius tangent to lower 14 1/20 line

2
PITCH CIRCLE (D)
ADDENDUM CIRCLE (DO)
PRESSURE ANGLE
BASE CIRCLE
ROOT CIRCLE (DR)
3
R r SetupCircular Thickness

• Offset the center line 1/2 the circular thickness
• Calculate the values of R r
• Draw circles with center at the intersection of
  the pitch circle the left offset of the center
  line (circular thickness).

4
r
Offset center line 1/2 of circular thickness
R
Center
5
Drawing Gear Tooth

• Using the intersection of base circle and the
  circumference of R r circles, draw tooth curves
  trim them.
• Draw radial line from base circle to center of
  pitch circle. Trim at root circle.
• Mirror the curves radial line about the
  vertical center line.

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7
Developing other teeth

• Draw addendum circle in layer visible trim out
  unneeded part.
• Array (polar) the one tooth developed. (360
  degrees 12 items - do not delete old objects)
• Draw root circle in layer visible. Freeze all
  unneeded layers. Trim at root circle.

8
Trim for all
9
Completion

• Change visible lines (gear) thickness to 1.
• Display all needed layers
• Clearly dimension (label) all.
• Using WORD show all calculations values
• Turn in presentation for check (grade).
• Plot

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