Question

What is the standard pressure angle for an involute system?

(a) 20 or 14.5 degree

(b) 20 or 30 degree

(c) 30 or 14.5 degree

(d) 40 or 30 degree

The question was asked in my homework.

My doubt is from Involute Curve in division Measurement and Testing of Gears of Engineering Metrology

Answer 1

The correct choice is (a) 20 or 14.5 degree

Easy explanation: The involute system has a standard value of pressure angle which is 20° or 14.5° whereas on the cycloidal system does not have a standard pressure angle, it varies from zero at pitch line to a maximum at the teeth tips.