There are many types of gears, such as spur gears, helical gears, bevel gears, helical gears, racks, etc. They can be broadly classified by looking at the positions of the axes, such as parallel trees, intersecting trees, and non-intersecting trees.
It is necessary to accurately understand the differences between gear types to achieve the power transmission required in mechanical designs. Even after choosing the general type, it is important to consider factors such as: dimensions (modulus, number of teeth, helix angle, face width, etc.), precision grade standards (ISO, AGMA, DIN), need for grinding of teeth and/or heat treatment, permitted torque and efficiency, etc.
Speed and torque are inversely and proportionally related when power is kept constant. Therefore, as the speed decreases, the torque increases accordingly.
The heart of a gear is the gears inside it. Gears work in pairs, interacting with each other to transmit energy. Read on to learn about the different types of tools and the applications and industries that use them.
straight gear
Spur gears transmit power through parallel shafts. The teeth of spur gears are parallel to the shaft axis. This causes the gears to produce radial reaction loads on the shaft, but not axial loads. Spur gears tend to be noisier than helical gears because they operate with a single line of contact between the teeth. As the teeth roll across the mesh, they roll away from contact with one tooth and accelerate to contact the next tooth. This is different from helical gears, which have more than one tooth in contact and transmit torque more smoothly.
Helical gears
Helical gears have teeth oriented at an angle to the shaft, unlike spur gears which are parallel. This causes more than one tooth to come into contact during operation, and helical gears can carry a greater load than spur gears. Due to the division of load between the teeth, this arrangement also allows helical gears to operate more smoothly and quietly than spur gears. Helical gears produce an axial load during operation that must be considered when used. Most closed gearboxes use helical gears.
Double helical gear
Double helical gears are a variation of helical gears in which two helical faces are placed close to each other with a space separating them. Each face has identical but opposite helix angles. The use of a double set of helical gears eliminates axial loads and offers the possibility of even greater tooth overlap and smoother operation. Just like worm gear, double worm gears are commonly used in closed gear transmissions.
Herringbone gear
Herringbone gears are very similar to double helical gears, but they do not have a gap that separates the two helical faces. Herringbone gears are typically smaller than comparable double helix gears and are ideal for high shock and vibration applications. Herringbone gears are not used very often due to manufacturing difficulties and high cost.
bevel gear
Bevel gears are most commonly used to transmit power between shafts that intersect at a 90-degree angle. They are used in applications where right angle gear transmission is required. Bevel gears are generally more expensive and are not capable of transmitting the same torque, per size, as a parallel shaft arrangement.
Helical gear
Helical gears transmit power at right angles to non-intersecting shafts. Helical gears produce an axial load and are suitable for high shock load applications, but offer very low efficiency compared to other gears. Due to this low efficiency, they are often used in low power applications.
Hypoid gear
Hypoid gears look a lot like a spiral bevel gear, but unlike spiral bevel gears, they operate on shafts that do not intersect. In the hypoid arrangement, because the pinion is placed in a different plane than the gear, the shafts are supported by bearings at both ends of the shaft.
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| cylindrical gear |
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| Helical gears |
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| Double helical gear |
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| Herringbone gear |
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| bevel gear |
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| Helical gear |
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| Hypoid gear |
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