There are many ways to define an involute curve. I take a simple trigonometry method in cartesian coordinates system to explain this. To start let me explain how we define an involute curve.
Just see the picture on the left side. There is pole at the center and a sting is attached to it.
In spur gears the gear teeth is straight and parallel to the axis of rotation but in helical gears the gear teeth is at an angle to the axis of rotation and follows a helical path (aka Helicoid) along the pitch circle diameter.
Formulas for helical gear:
Transverse_module = normal_module / cos (helix_angle)
Normal_circular_pitch = pi * normal_module
Transverse_circular_pitch = pi * transverse_module
Transverse_pressure_angle = atan ((tan (normal_pressure_angle))/(cos (helix_angle)))
Outer_Diameter = pitch_diameter + (2 * normal_module)
Root_diameter = pitch_diameter -
Base_diameter = pitch_diameter * cos (transverse_pressure_angle)
Normal_tooth_thickness = (pi * normal_module) / 2
Transverse_tooth_thickness = (pi * transverse_module) / 2
Lead = pi * Pitch_diameter / tan (Helix_angle)
Nokia has taken many steps to regain its number one spot in mobile phone market which is currently in the hands of SAMSUNG. SAMSUNG rapidly gained the number one spot particularly because of the GALAXY series smart phones.
Nokia joined hands with Microsoft to produce windows smart phones with its first generation Lumia series and it hit the market in November 2011. Since then Nokia’s market share has been raising but not as expected.