For an involute gear, the ratio, pitch circle radius/ base circle radius is (φ is the pressure angle)
Base circle radius = Pitch circle radius x cos φ
Th e tooth profile most commonly used in gear drive for power transmission is
Due to ease of standadization, manufacturing and low cost of production, the use of involute te e th has becom e universal by e n tire ly superseding the cycloidal teeth shape.
The size of gears is usually specified by
The contact ratio of gears is always
For continuous transmission of motion, at least one tooth of one wheel must be in contact with another tooth of second wheel. Therefore, the contact ratio must be greater than unity.
If angle of approach, pitch angle and angle of recess is given by 11°, 20° and 15° respectively, what is the contact ratio of gear?
The gears are interchangeable if they have
If a reduction ratio of about 50 is required in a gear drive then the most appropriate gearing would be
The pressure angle of a spur gear normally varies from
Select the positive drive amongst the following:
Gear drives use no intermediate link or connector and transmit the motion by direct contact. Hence, gears ensure definite velocity ratio and provide a positive drive.
The motion transmitted between the teeth of two spur gears is generally
Pair of teeth is at pitch point have pure rolling action. At away other position, they have sliding as well as rolling velocity.