Because spiral bevel gears do not have the offset, they have less sliding between the teeth and are better than hypoids and create less heat during procedure. Also, among the main benefits of spiral bevel gears may be the relatively large amount of tooth surface that is in mesh throughout their rotation. For this reason, spiral bevel gears are an ideal option for high rate, high torque applications.
Spiral bevel gears, like various other hypoid gears, are made to be what’s called either correct or left handed. A right hand spiral bevel gear is thought as having the external half a tooth curved in the clockwise direction at the midpoint of the tooth when it’s viewed by searching at the facial skin of the apparatus. For a left hands spiral bevel equipment, the tooth curvature would be in a counterclockwise direction.
A equipment drive has three main functions: to increase torque from the generating equipment (motor) to the driven devices, to reduce the speed produced by the motor, and/or to improve the path of the rotating shafts. The bond of this equipment to the apparatus box can be accomplished by the use of couplings, belts, chains, or through hollow shaft connections.
Speed and torque are inversely and proportionately related when power is held constant. Therefore, as speed decreases, torque raises at the same ratio.
The center of a gear drive is actually the gears within it. Gears operate in pairs, engaging one another to transmit power.
Spur gears transmit power through shafts that are parallel. The teeth of the spur gears are parallel to the shaft axis. This causes the gears to create radial response loads on the shaft, but not axial loads. Spur gears tend to end up being noisier than helical gears because they work with a single line of contact between tooth. While the teeth are rolling through mesh, they roll from connection with one tooth and accelerate to get hold of with another tooth. This is unique of helical gears, that have several tooth connected and transmit torque more smoothly.
Helical gears have teeth that are oriented at an angle to the shaft, as opposed to spur gears which are parallel. This causes several tooth to communicate during procedure and helical gears can 
handle holding more load than spur gears. Due to the load posting between teeth, this arrangement also allows helical gears to use smoother and quieter than spur gears. Helical gears create a thrust load during operation which must be considered if they are used. Most helical spiral bevel gear motor enclosed gear drives use helical gears.
Double helical gears certainly are a variation of helical gears where two helical faces are positioned next to one another with a gap separating them. Each face has identical, but opposite, helix angles. Having a double helical set of gears eliminates thrust loads and offers the possibility of even greater tooth overlap and smoother procedure. Just like the helical gear, double helical gears are generally found in enclosed gear drives.
Herringbone gears are extremely similar to the double helical gear, but they do not have a gap separating the two helical faces. Herringbone gears are typically smaller than the comparable double helical, and so are ideally fitted to high shock and vibration applications. Herringbone gearing isn’t used very often due to their manufacturing problems and high cost.
While the spiral bevel gear is truly a hypoid gear, it isn’t always seen as one because it doesn’t have an offset between the shafts.
One’s teeth on spiral bevel gears are curved and have one concave and one convex side. They also have a spiral angle. The spiral angle of a spiral bevel gear is defined as the angle between the tooth trace and an component of the pitch cone, similar to the helix angle found in helical gear teeth. In general, the spiral angle of a spiral bevel gear is defined as the imply spiral angle.