The Different Types Of Gears

Functions of a Gearbox

 

A gearbox, also known as a Gear Drive, has three main functions: to increase torque from the driving equipment (motor) to the driven equipment, to reduce the speed generated by the motor, and/or to change the direction of the rotating shafts. The connection of this equipment to the gearbox can be accomplished using couplings, belts, chains, or hollow shaft connections. 

 

Speed and torque are inversely and proportionately related when power is held constant. Therefore, as speed decreases, torque increases at the same ratio.

 

The heart of a gear drive is the gears within it. Gears operate in pairs, engaging one another to transmit power. Read on to learn the different types of gear and the applications and industries that utilize them.

Spur Gear

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 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 teeth. While the teeth are rolling through mesh, they roll off of contact with one tooth and accelerate to contact with the next tooth. This is different than helical gears, which have more than one tooth in contact and transmit torque more smoothly.

Helical Gear

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 can carry 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 produce a thrust load during operation which needs to be considered when they are used. Most enclosed gear drives use helical gears.

Double Helical Gear

Double helical gears are a variation of helical gears in which two helical faces are placed next to each other with a gap separating them. Each face has identical, but opposite, helix angles. Employing a double helical set of gears eliminates thrust loads and offers the possibility of even greater tooth overlap and smoother operation. Like the helical gear, double helical gears are commonly used in enclosed gear drives.

Herringbone Gear

Herringbone gears are very 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 are ideally suited for high shock and vibration applications. Herringbone gearing is not used very often due to their 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 a right angle gear drive is required. Bevel gears are generally more costly and are not able to transmit as much torque, per size, as a parallel shaft arrangement.

Worm Gear

Worm gears transmit power through right angles on non-intersecting shafts. Worm gears produce thrust load and are good for high shock load applications but offer very low efficiency in comparison to the other gears. Due to this low efficiency, they are often used in lower horsepower applications.

Hypoid Gear

Hypoid gears look very much like a spiral bevel gear, but unlike spiral bevel gears, they operate on shafts which do not intersect. In the hypoid arrangement because the pinion is set on a different plane than the gear, the shafts are supported by the bearings on either end of the shaft.

	Industries	Applications	Rexnord Products
Spur Gear	·         Food ·         Beverage ·         Automotive ·         Forest ·         Energy ·         Unit handling	·         Small conveyors ·         Package handling equipment ·         Farm machinery ·         Planetary gear sets ·         Automotive	·         Planetgear
Helical Gear	·         Cement ·         Food ·         Beverage ·         Mining ·         Marine ·         Energy ·         Forest ·         Bulk material handling	·         Medium to large conveyors ·         Mixers ·         Large pumps ·         Water treatment ·         Crushers	·         V-Class ·         Quadrive ·         UltraMax ·         Ultramite
Double Helical Gear	·         Mining ·         Marine ·         Heavy industry	·         Milling ·         Steam turbines ·         Ship propulsion
Herringbone Gear	·         Mining ·         Marine ·         Heavy industry	·         Milling ·         Steam turbines ·         Ship propulsion
Bevel Gear	·         Cement ·         Food ·         Beverage ·         Mining ·         Energy ·         Bulk material handling	·         Medium to large conveyors ·         Mixers ·         Crushers ·         Water treatment	·         V-Class ·         Ultramite
Worm Gear	·         Food ·         Beverage ·         Automotive ·         Forest ·         Energy ·         Unit handling	·         Small conveyors ·         Package handling equipment ·         Farm machinery	·         Ultramite ·         Omnibox
Hypoid Gear	·         Cement ·         Food ·         Beverage ·         Mining ·         Energy ·         Bulk material handling	·         Small to medium conveyors ·         Small mixers ·         Crushers ·         Water treatment

 

For More about Gear

Ship's Frame Structures

 In ships, frames are ribs that are transverse bolted or welded to the keel. Frames support the hull and give the ship its shape and strength.

In wooden shipbuilding, each frame is composed of several sections, so that the grain of the wood can follow the curve of the frame. Starting from the keel, these are the floor (which crosses the keel and joins the frame to the keel), the first futtock, the second futtock, the top timber, and the rail stanchion.[1] In steel shipbuilding, the entire frame can be formed in one piece by riveting or welding sections; in this case the floor remains a separate piece, joining the frame on each side to the keel.

Frame numbers are the numerical values given to the frames; they begin at 1 with the forward-most frame, and numbers increase sequentially towards the stern. The total number vary per the length of a ship. Frame numbers tell you where you are in relation to the bow of the ship; the numbers increase as you go aft.[2]

The frames support lengthwise members which run parallel to the keel, from the bow to the stern; these may variously be called stringers, strakes, or clamps.[3] The clamp supports the transverse deck beams, on which the deck is laid.

Construction of ships and other floating vessels.

 

Shipbuilding is the construction of ships and other floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to before recorded history.

Shipbuilding and ship repairs, both commercial and military, are referred to as "naval engineering". The construction of boats is a similar activity called boat building.

The dismantling of ships is called ship breaking.

What is Ship's Hull?

 A hull is that part of ship that extends below the waterline to cover and protect water from getting in. You can consider it as the shell which protects the inside treasures from outside environment.

Ship's Hull

Everything that is stored and situated within the main ship structure is covered and protected by the ships hull. It includes the key parts of the ship such as bow, deck, the bottom keel and the both sides of the ship.

Various parts of Ship's Hull

They are made up of series of plates jointed together called stakes along with other structural member such as plating and stiffeners.

A stiffener consists of structural parts such as longitudinal and transverse frames, bulkhead stiffness, girders and beam. While ships plating consists mainly of deck platting along with bottom, bulkhead and side platting.

 

Hull Design

Ships hull are designed as such to offer minimum resistance to water, is feasible and economical to construct without losing on much needed cargo space. One can easily calculate and improve the overall efficiency of a ship calculating and reducing hull’s resistance to ships motion.

 

FUNCTIONS

Made of steel the key role of ships hull is to maintain its water-tight integrity and reduce water drag. And so hull plays a major role in determining the overall efficiency of a ship. Ships hull are thus coated with special paints that not only reduce frictional drag but also avoid marine growth which further increases the resistance to ships motion. Thus ships hull are cleaned and repainted with special coating during dry dock operation.