Explanation of the formation of the involute curve of the involute straight/helical cylindrical gear

The descriptions of the involute formation of involute straight/helical cylindrical gears are as follows, for your reference and understanding. For any unclear points or related requirements, you can consult EP Machining for free.

1. The formation of the involute line of the involute helical cylindrical gear:

Involute helical cylindrical gearThe formation principle of the tooth surface is similar to that of the involute spur gear. The difference is that the line KK′ on the generating surface is not parallel to the line NN′, that is, it is not parallel to the gear axis.The plane forms an angle βb with the base round bar bus NN'.

Therefore, when the generating surface is purely rolling along the base cylinder, each point on the straight line KK′ starts from the contact point of the base cylinder surface to form an involute line, and each point on the straight line KK′ develops an involute line. The collection of lines is the tooth surface of the helical cylindrical gear.

it's easy to see,gearThe intersection line (tooth profile curve on the end surface) on the plane (gear surface) perpendicular to the axis of the base cylinder is still an involute.And because this type of involutes have exactly the same base cylinder, their shapes are all the same, but the starting point of the development is the same, that is, the starting point is at each point on the spiral KK'.Therefore, the tooth surface is an involute spiral surface.

2. The formation of the involute of the involute spur gear:

The tooth profile surfaces of the two wheels touch along a straight line KK′ parallel to the gear shaft, and KK′ is parallel to the tangent line NN′ of the generating surface on the base cylinder.When the generating surface is purely rolling along the base cylinder, the trajectory generated by the straight line KK′ in space is an involute surface, that is, the tooth profile surface of the spur gear.

It is not difficult to see that the end tooth profile curve of the involute helical cylindrical gear is still an involute.The involute spur gear can be regarded as a special case of the involute helical gear.

From the end point of view, the transmission of two involute helical cylindrical gears is equivalent to the transmission of two involute spur cylindrical gears, so it also conforms to the basic law of tooth profile meshing.

The above is the description of the involute formation of the involute straight/helical cylindrical gear shared by EP Gear Machining today, including but not limited to, if you have more questions, you can ask a technician for help.