Because spiral bevel gears do not have the offset, they have less sliding between the teeth and are more efficient than hypoids and produce less heat during procedure. Also, one of 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 a perfect option for high speed, high torque applications.
Spiral bevel gears, like additional hypoid gears, are made to be what is called either correct or left handed. A right hand spiral bevel gear is defined as having the external half of a tooth curved in the clockwise direction at the midpoint of the tooth when it’s viewed by looking at the facial skin of the gear. For a left hand spiral bevel gear, the tooth curvature would be in a counterclockwise path.
A gear drive has three main functions: to improve torque from the traveling equipment (motor) to the driven products, to lessen the speed produced by the electric motor, and/or to change the direction of the rotating shafts. The connection of this equipment to the gear box can be achieved by the use of couplings, belts, chains, or through hollow shaft connections.
Velocity and torque are inversely and proportionately related when power is held continuous. Therefore, as speed decreases, torque increases at the same ratio.
The center of a gear drive is obviously the gears within it. Gears operate in pairs, engaging one another to transmit power.
Spur gears transmit power through shafts that are parallel. One’s teeth of the 
spur gears are parallel to the shaft axis. This causes the gears to produce radial response loads on the shaft, however, not axial loads. Spur gears tend to be noisier than helical gears because they function with a single line of contact between teeth. While the tooth are rolling through mesh, they roll from contact with one tooth and accelerate to contact with the next tooth. This is different than helical gears, that have several tooth connected and transmit torque more efficiently.
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 communicate during operation and helical gears can handle transporting more load than spur gears. Due to the load sharing between teeth, this arrangement also allows helical gears to use smoother and quieter than spur gears. Helical gears create a thrust load during procedure which must be considered if they are used. Most enclosed gear helical spiral bevel gear motor drives use helical gears.
Double helical gears 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 group 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 found in enclosed gear drives.
Herringbone gears are extremely like the double helical equipment, but they do not have a gap separating the two helical faces. Herringbone gears are typically smaller compared to the comparable double helical, and are ideally suited for high shock and vibration applications. Herringbone gearing isn’t used very often because of their manufacturing problems and high cost.
While the spiral bevel gear is truly a hypoid gear, it is not always considered one because it doesn’t have an offset between the shafts.
One’s teeth on spiral bevel gears are curved and also have one concave and one convex side. There is also a spiral angle. The spiral angle of a spiral bevel equipment is thought as the angle between your tooth trace and an element of the pitch cone, like the helix angle found in helical gear teeth. Generally, the spiral angle of a spiral bevel gear is defined as the suggest spiral angle.