The working principle of gears is to engage with each other for power transmission, which has different tooth width, tooth surface width, diameter and tooth pitch. Because they can provide high performance, therefore, gears gradually replace the old belt and pulley, gears are widely used in the aviation industry, mining industry, automobile industry, pharmaceutical industry, textile industry...
Gear types on the market
The difference between the existing gear types on the market lies in the position and shape of the teeth, which are divided into parallel shaft gear and non-parallel shaft gear. Parallel shaft gear includes spur gear, helical gear and double-helical gear or herringbone gear. Non-parallel shaft gears include helical (cross helical) gears, straight or straight bevel gears and helical bevel gears.
Straight tooth cylindrical gears, which generate radial reaction forces on the shaft and transfer energy through the parallel shaft, are the simplest type of gears and are usually used at medium to low speeds, producing noise as the speed increases.
Helical cylindrical gears, which transmit power in the same manner as spur gears, maybe non-parallel (helical conveyor top) or parallel. Their teeth are tilted relative to the axis of rotation, transmitting more motion and higher speed than straight cylindrical gears, with good fluidity and less vibration, but more lubricating oil is needed to prevent faster wear.
Double helical or herringbone gears, combined with left and right helices, have symmetrical grooves that generate opposite and equal thrust, and they eliminate axial thrust, meaning that bearings and supports do not need to absorb axial thrust.
Helical gears (cross helical gears), whose motion is mainly wedge-shaped or helical, whose teeth are highly sliding and easy to assemble, have the same normal diameter groove, and they may go in the same direction or in the opposite direction.
Straight teeth or bevel gears, now rarely used, move in an axial direction through the conical surface in the same plane, usually at right angles. The tooth meshing point is at the intersection of the axes, usually used to slow down, the two axes intersect at right angles and there is noise during operation.
Spiral bevel gears, whose contact surface is larger than that of straight bevel gears, can be cut for axial motion and can operate at speeds lower than the transmission shaft.
Hypoid gears, whose active pinions are off-center, require pressurized oil, but have a long service life, low noise, and outstanding performance. They are used in ships and industrial machines.
Worm and worm wheel screws, which consist of a worm and a driven helical gear, drive the gear drive. The most common Angle between shafts is a right angle, which can be changed depending on the function.
Special purpose gear type
An inner gear or ring of teeth, similar to a spur gear, whose teeth are not polished on the outer surface, but on the inner side of the wheel or edge ring, and the pinion drives the inner gear in the direction of angular velocity.
The planetary gear is a gear transmission system in which a central gear consists of one or more external gears that are commonly used in automobile transmissions.
Rack and pinion, used in lathes to move longitudinal brackets, have no transmission ratio but only a length ratio, in which case the rack falls under the category of infinite diameter gears.
The material used to make gears
Tempered steel is one of the most commonly used materials for all kinds of gears. Aluminum is also a common material. Other materials used are: high-strength steel, forged stainless steel, copper-based alloys, cast or forged aluminum alloys, cast or gray cast iron, and magnesium alloys. For plastic materials with self-lubricating properties: polycarbonate (PC), polyamide or PVC and acetal resin is particularly outstanding. In addition, among flame-retardant materials, the most commonly used are PEEK, PTFE and liquid crystal polymers (LCP).
The application and utility of gear
In the agricultural sector, for example, they perform mechanized tasks such as sowing, farming, or irrigation. In the automotive sector, they are often used as force transmitters and speed regulators. In wind power, gears increase the speed of generators. In addition, gears have four applications and are used in many sectors and fields.
Hydraulic pump
It converts rotating mechanical energy into hydraulic energy. It consists of a pair of meshing gears, the driving shaft and the driver of the motor, and the contact between the gears' teeth will cause displacement.
reducer
They use circular and toothed gear pairs to effectively and safely reduce motor speeds, and use gears of different diameters to reduce speed ratios.
differential
The differential is composed of two planetary gears and two driven or tapered pinion gears connected to the axle end of the wheel. The other two driven wheels or tapered pinion gears are located at the end of the axle bearing shaft of the driven wheel.
transmission
It connects the motor to the driveline by a different transmission ratio, reduces engine speed, connects to the motor by a clutch or torque converter, and supports the gear shaft by a ball shaft.
