Because spiral bevel gears don’t have the offset, they have less sliding between the teeth and are better than hypoids and produce less heat during operation. Also, one of the main advantages of spiral bevel gears is the relatively large amount of tooth surface that is in mesh throughout their rotation. Because of this, spiral bevel gears are a perfect option for high quickness, high torque applications.
Spiral bevel gears, like various other hypoid gears, are made to be what 
is called either right or left handed. The right hands 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’s viewed by searching at the face of the gear. For a left hands spiral bevel equipment, the tooth curvature would be in a counterclockwise path.
A gear drive has three primary functions: to increase torque from the driving equipment (motor) to the driven apparatus, to reduce the speed generated by the engine, and/or to change the path of the rotating shafts. The connection of the equipment to the gear box can be accomplished by the use of couplings, belts, chains, or through hollow shaft connections.
Acceleration and torque are inversely and proportionately related when power is held constant. Therefore, as swiftness decreases, torque boosts at the same ratio.
The center of a gear drive is actually the gears within it. Gears work in pairs, engaging each other 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 reaction 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 tooth. While the teeth are rolling through mesh, they roll off of connection with one tooth and accelerate to get hold of with another tooth. This is different than helical gears, that have several tooth in contact and transmit torque more efficiently.
Helical gears have teeth that are oriented at an angle to the shaft, unlike spur gears which are parallel. This causes more than one tooth to be in contact during operation and helical gears are capable of holding more load than spur gears. Due to the load sharing between teeth, this arrangement also allows helical gears to operate smoother and quieter than spur gears. Helical gears create a thrust load during operation which must be considered if they are used. The majority of enclosed gear 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 encounter has identical, but opposing, helix angles. Having a double helical set of gears helical spiral bevel gear motor eliminates thrust loads and will be offering the possibility of even greater tooth overlap and smoother operation. Like the helical gear, dual 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 usually smaller compared to the comparable double helical, and so are ideally fitted to high shock and vibration applications. Herringbone gearing is not used very often due to their manufacturing issues and high cost.
As the spiral bevel gear is actually a hypoid gear, it is not always considered one because it doesn’t have an offset between the shafts.
The 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 the tooth trace and an element of the pitch cone, like the helix angle within helical gear teeth. In general, the spiral angle of a spiral bevel equipment is defined as the imply spiral angle.