The critical component of a transmission device is the gear within it. Gears are a type of commonly used mechanical parts, CNC machining service is one of the solutions of gear manufacturing. We have introduced the gear cutting process before. In this article, we are going to talk about what is gear as well as different types of gears and their applications.
A gear is a kind of mechanical part with cut teeth for continuous meshing on the rim to transmit motion and power, also known as a cog, which needs to mesh with another toothed part or machine component in mechanical devices. Gears are used to change the direction of movement and increase or decrease the speed of rotation and the output torque. So geared devices can easily change the speed, torque, and direction of a power source.
Based on the position of axes of the shafts, gears can be divided into the following types. There are also miter gears, internal gears, screw gears, hypoid gears, and more classifications.
– Parallel: spur gear, helical gear, and rack & pinion
– Intersecting: bevel gear
– Non-parallel and non-intersecting: worm and worm gears
1. Spur gears: spur gears are cylindrical gears with a toothed align which is parallel to the shaft, used to transmit power from one shaft to another parallel one, and increase or decrease the torque of a given object. They are the most widely used gears that can achieve high accuracy with relatively easy and economic production processes. The simple design and ease of maintenance are also the advantages of spur gears. You can often find them in an electric screwdriver, oscillating sprinkler, windup alarm clock, washing machine, clothes dryer, construction equipment, fuel pumps, and mills.
2. Helical gears: similar to spur gears, helical gears are cylindrical gears used with parallel shafts, but the teeth of helical gears are not parallel to the axis of rotation, are set at an angle. The gradual engagement makes helical gears operate more smoothly and quietly than spur gears. So they have better teeth meshing than spur gears and superior quietness. Helical gears can transmit higher loads, which makes them ideal for high-speed applications. When using helical gears, they will create thrust force in the axial direction necessitating the use of thrust bearings, helical gears come with the right hand and left hand twists requiring opposite hand gears for meshing pair. To avoid axial thrust, two helical gears of the opposite hand can be mounted side by side to cancel the resulting thrust forces. A herringbone gear looks like the assembly of double helical gears, but they don’t have a gap separating the gear faces. In such a condition, there is no thrust loading on the bearings.
3. Rack and Pinion: rack and pinion is a type of gear that comprises a circular gear (the pinion) engaging a linear gear (the rack) which operates to translate rotational motion into linear motion. The rack is a toothed bar or rod. Driving the pinion into rotation causes the rack to be driven linearly, driving the rack will cause the pinion to be driven into the rotation. Rack and pinion provide less mechanical advantages than other mechanisms such as recirculating ball. When it comes to the applications of this gear, an example is the steering system used in automobiles to convert the rotation of the steering wheel into the left-to-right motion of the tie rods.
4. Bevel gears: bevel gears are a type of gear where the axes of the two shafts intersect and the tooth-bearing faces of the gears are conical, bevel gears are often mounted on shafts that are 90 degrees apart but can be designed to work at other angles as well. Bevel gears are used in differential drives which can transmit power to two axles spinning at different speeds, and also used as the main mechanism for a hand drill, the handle of the drill is turned in a vertical direction, the bevel gears change the rotation of the chuck to a horizontal rotation, the bevel gears and a hand drill have the added advantage of increasing the speed of rotation of the chuck, this makes it possible to drill a range of materials. The diverse applications of bevel gears including locomotives, marine, automobile, printing presses, cooling towers, power plants, steel plants, railway track, inspection machines.
5. Worm and worm gears: in the form of a screw meshes with a worm gear which is similar in appearance to a spur gear, the two elements are also called the worm screw and worm wheel, the terminology is often confused by imprecise use of the term, here refer to the worm and worm gear or worm drive as a unit like other gear arrangements. The axes of worm gears shafts cross in space. The shaft of worm gears lie in parallel planes and may be skewed at any angle between zero and right angle. Worm gears are used to transmit power at 90 degrees and where a high reduction of rotational speed is required. Their common applications are presses, rolling mills, conveying engineering, mining industry machines, lifts, elevator, escalator drive applications due to their compact size, and the non-reverse ability of the gear.