spur gear
most commonGearIt is a straight toothed cylindrical gear used for large gear reduction. The teeth on a spur gear are straight and mounted parallel on different shafts. Spur gears are used in washing machines, screwdrivers, wind-up alarm clocks, and other equipment. Because gears mesh and collide, each impact makes a loud noise and causes vibration, which is why straight cylindrical gears are not used in machinery such as automobiles. A normal gear ratio ranges from 1:1 to 6:1.
helical gear
Helical gears work smoother and quieter than spur gears due to tooth interaction. The teeth on a helical gear are cut at an angle to the surface of the gear. When two teeth begin to meet, contact is gradual - starting at one end of the tooth and maintaining contact as the gear rotates to full engagement. Typical helix angles range from about 15-30 degrees. Thrust loads vary directly with the magnitude of the tangent to the helix angle. Helicals are the most commonly used gears in transmissions. They also generate a significant amount of thrust and use bearings to help support the thrust load. Helical gears can be used to adjust the angle of rotation by 90 degrees. When mounted on a vertical shaft. Its normal ratio range is 3:2 to 10:1.
pinion gear
Bevel gears are used to change the direction of rotation of a shaft. Bevel gears are available with straight, spiral or hypoid shaped teeth. Straight teeth have similar characteristics to spur gears and mesh with great influence. Similar to spur gears, the normal range of ratios for straight bevel gears is 3:2 to 5:1.
Helical teeth operate in the same way as helical gears. They produce less vibration and noise than straight teeth. The right hand side of the helical bevel is the outer half of the tooth, inclined to travel clockwise from the shaft plane. The left hand side of the helical bevel travels in a counterclockwise direction. Normal gear ratios range from 3:2 to 4:1.
Hypoid gears are helical gears that are rotationally hyperbolic rather than conical in shape. Hypoid gears place the pinion on a ring or crown wheel. This allows the pinion to have a larger diameter and provides more contact area.
Pinions and gears are usually always opposite, and the helix angle of a pinion is usually greater than that of a gear. Hypoid gears are used in power transmission systems because of their large ratios. Normal gear ratios range from 10:1 to 200:1.
worm gear
Worm gears are used for large gear reduction. Ratios ranging from 5:1 to 300:1 are typical. The setup is such that the worm can turn the gear, but the gear cannot turn the worm. The angle of the worm is shallow, so the gear remains in place due to friction between the two. The drive is suitable for conveyor belt systems where the locking feature can be used as a brake or emergency stop.