Gears are essentially wheels with specialized teeth that move one shaft to move another. A specialized group of gears known as spur gears are cylindrical gears with spindles that run parallel to the axis of rotation.
Because of this construction, spur gears when used are efficient conduits of power. Furthermore, the overall design is compact and installation of spur gears is quite easy to do. The design also provides a constant velocity ratio, which avoid erratic distribution of torque. This makes spur gears highly reliable in delivery and performance. There is very little maintenance involved, only oiling and cleaning to avoid any issues as to the teeth becoming brittle.
There are drawbacks though in the use of spur gears. Compared to belt drives, spur gears are more expensive but this is an initial expense that is more cost effective in the long run. Belt drives, not only require the same maintenance requirements as spur gears, replacement of the belt itself becomes more commonplace over the lifespan of the equipment.
Another drawback is the distance between gears. Being spur gears, the gears need to be in constant contact with one another in order to perform its tasks. This limitation requires the gears to be meshed together at all times. This meshing results in great friction as well as great stress. The friction generates both heat and sound, which results in high ambient noise produced as well as heat generation near and around the spur gears. Because of the friction between the spur gears, the splines undergo great stress in terms of heat as well as weight over time.
As can be seen, spur gears provide both benefits and drawbacks when in use. Spur gears, when in use, provide benefits that outweigh the drawbacks. The long-term reliability and consistency of spur gears trump any other kind of drive design in the market today.