Gears are key components of many motors and machines. Gears can increase torque output by providing gear reduction and adjust the direction of rotation of shafts, such as the rear wheels of a car. Here are some basic types of gears and how they differ from each other.



Spur gear
The most common gears are spur gears, which are used for large gear reductions. The teeth on spur gears are straight and mounted in parallel on different shafts. Spur gears are used in washing machines, screwdrivers, clockwork alarm clocks, and other appliances. Because the gears mesh and collide, each impact generates loud noise and causes vibration, which is why spur gears are not used in machinery such as automobiles. A normal gear ratio range is 1:1 to 6:1.



Helical gear
Due to the interaction of the teeth, helical gears work more smoothly and quietly than spur gears. The teeth on the helical gear are cut at an angle to the gear surface. As the two teeth begin to engage, the contact is gradual - starting at one end of the teeth and maintaining contact as the gears rotate to full engagement. A typical helix angle range is about 15-30 degrees. The thrust load varies directly with the magnitude of the tangent to the helix angle. Spirals are the most commonly used gears in transmissions. They also generate a lot of thrust and use bearings to help support thrust loads. The helical gear can be used to adjust the rotation angle by 90 degrees. When mounted on a vertical axis. Its normal gear ratio range is 3:2 to 10:1.





Bevel gear
Bevel gears are used to change the direction of rotation of the shaft. Bevel gears have straight, helical or hypoid shaped teeth. Spur gears have similar characteristics to spur gears and also have a large impact when meshing. Similar to spur gears, the normal ratio range of spur bevel gears is 3:2 to 5:1.

Helical teeth operate the same as helical gears. They produce less vibration and noise than straight teeth. The right side of the helical ramp is the outer half of the tooth, inclined to travel clockwise from the axis plane. The left hand of the spiral bevel travels in a counter-clockwise direction. The normal gear ratio range is 3:2 to 4:1.

A hypoid gear is a helical gear whose shape is a hyperboloid of revolution rather than a cone. Hypoid gears place the pinion on the ring gear or crown wheel. This allows the pinion to be larger in diameter and provide more contact area.

Pinions and gears are usually always opposite, and the helix angle of the pinion is usually greater than the angle of the gear. Hypoid gears are used in power transmission systems due to their large transmission ratios. The normal gear ratio range is 10:1 to 200:1.



worm gear
Worm gears are used for large gear reductions. Gear ratios ranging from 5:1 to 300:1 are typical. The purpose of the setting is so that the worm can turn the gear, but the gear cannot turn the worm. The angle of the worm is shallow so the gears stay in place due to the friction between the two. The drive is suitable for conveyor belt systems, where the locking function can be used as a brake or as an emergency stop.