Taking all this into account, you must think that the gear was designed by a person, that person most likely has used some CAD software, and in most CAD software there are already standard modules. And helix directions (one gear must have a “right” helix direction and the other “left”).And.The first thing that you should keep in mind is that for two helical gears to mesh well, it is necessary that both have: For this reason, it is that helical gears are usually used in vehicles intended for “common” driving.

In private vehicles, it is preferable to reduce noise and obtain a more “gradual and smooth” power transmission, thus gaining more comfort. In a racing vehicle, noise does not matter so much, in addition, it is better not to have axial loads since it reduces the need to use mechanical devices that reduce axial friction (for example, thrust bearings), therefore, simple bearings can be used, reducing overall weight, an important issue in racing vehicles. It is also necessary to take into account that a spur gear is cheaper and easier to manufacture than a helical gear.įor the reasons mentioned above, helical gears are often chosen for private vehicles and spur gears for racing vehicles. In addition, it should be noted that, if we had a spur gear and a helical gear of the same dimensions and similar characteristics, the teeth of the helical gear would have a greater contact area due to their inclination, therefore, its teeth would be more resistant.

The third and final factor is the way the gear teeth come into contact, spur gears do not come into contact “smoothly and gradually” while helical gears do come into contact “smoothly and gradually”, allowing the helical gears to be better to transmit force and speed gradually.

The second factor is noise, spur gears at high speeds are much louder than helical gears.

Axial load is the most important factor, helical gears produce axial load and spur gears do not.

Why choose one or the other? There are generally three salient factors that are taken into account in making this decision:

The spur and helical gears are the two most common types of gears.

Helical gear design in solidworks