Because spiral bevel gears don’t have the offset, they have less sliding between the teeth and are better than hypoids and create less heat during operation. Also, among the main benefits of spiral bevel gears is the relatively massive amount tooth surface that is in mesh throughout their rotation. Because of this, spiral bevel gears are an ideal option for high quickness, high torque applications.
Spiral bevel gears, like other hypoid gears, are made to be what is called either right or left handed. The right hand spiral bevel equipment is defined as having the outer half a tooth curved in the clockwise path at the midpoint of the tooth when it is viewed by searching at the face of the apparatus. For a left hand spiral bevel equipment, the tooth curvature will be in a counterclockwise path.
A gear drive has three primary functions: to improve torque from the generating equipment (engine) to the driven gear, to reduce the speed generated by the engine, and/or to change the path of the rotating shafts. The connection of this equipment to the apparatus box can be accomplished by the usage of couplings, belts, chains, 
or through hollow shaft connections.
Velocity and torque are inversely and proportionately related when power is held constant. Therefore, as rate decreases, torque raises at the same ratio.
The cardiovascular of a gear drive is obviously the gears within it. Gears work in pairs, engaging each other 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 produce radial response loads on the shaft, but not axial loads. Spur gears tend to become helical spiral bevel gear motor noisier than helical gears because they function with a single line of contact between tooth. While the the teeth are rolling through mesh, they roll from contact with one tooth and accelerate to get hold of with another tooth. This is different than helical gears, that have more than one 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 more than one tooth to be in contact during operation and helical gears can handle transporting more load than spur gears. Because of the load sharing between teeth, this set up also enables 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. Many enclosed gear drives make use of helical gears.
Double helical gears are a variation of helical gears in which two helical faces are positioned next to one another with a gap separating them. Each face has identical, but reverse, helix angles. Having a double helical set of gears eliminates thrust loads and will be offering the possibility of sustained tooth overlap and smoother operation. Like the helical gear, double helical gears are generally used in enclosed gear drives.
Herringbone gears are very like the double helical equipment, but they do not have a gap separating the two helical faces. Herringbone gears are usually smaller than the comparable double helical, and are ideally fitted to high shock and vibration applications. Herringbone gearing is not used very often because of their manufacturing complications and high cost.
As the spiral bevel gear is actually a hypoid gear, it isn’t always viewed as one because it doesn’t have an offset between your shafts.
One’s teeth on spiral bevel gears are curved and have one concave and one convex side. They also have a spiral position. The spiral angle of a spiral bevel equipment is defined as the angle between your tooth trace and an component of the pitch cone, similar to the helix angle found in helical gear teeth. In general, the spiral position of a spiral bevel equipment is defined as the mean spiral angle.