Types of Gear Materials
The design and development of gears is very dependent on the materials used to produce them. In the manual for gear development, there are three factors that are essential – strength, durability, and cost. An addendum to the cost is the type of materials to be used and the equipment necessary to manufacture the gears. What is most amazing about them is that they can be produced from a wide variety of materials including steel, stainless steel, brass, bronze, cast iron, iron, aluminum, and plastic with steel being the most common.
As with any product, the first consideration when deciding on the type of gear material is to consider the use of the gear. Moist or wet conditions will require gear that does not rust and repels water. Highly stressful uses will need one that can withstand elevated levels of torque and resistance. Simple and less complex situations are able to use lightweight materials where there is little concern for severe use. Before making the final choice, it is important to know the conditions, needed strength, and how long it will be used.
Stainless steel is always a good choice for several environments since it has chromium content that does not rust and can withstand very stressful conditions. A very popular use for stainless steel is in saltwater sailing since it is strong enough to maintain lines and not slip as well as water repellent. Stainless steel gears tend to be very expensive and may need to be specially ordered depending on their intended use.
The most common type of gear is steel, which has been used for many years. A very strong metal that holds it shape, steel is found in almost every type of engine since it can withstand the torque and stress engines produce. In automobiles, steel gears are used in the production of transmissions since steel allows the smooth transfer of horsepower from one gear to the next.
Brass lacks the strength of steel but is sturdy enough to endure certain stressful conditions. What makes brass so attractive is its shining appearance that gives the impression of gold. Brass gears are generally used where low friction is required with very little noise. They are ideal for clocks and locks since they rarely wear out providing consist high-quality performance.
Cast iron is an excellent material for the production of gears. It lasts a long time and can be molded into complicated shapes through casting. Its main attraction is its ability to withstand compressive force. This feature makes it very durable and lasting, an essential quality for gears.
Plastic has become widely used in a variety of industries including gear manufacturing. The first thing that comes to mind when analyzing plastic is its low cost, which is a fraction of the other materials. Gears made of plastic are lightweight, rust resistant, very quiet, and can be molded into many different sizes and shapes. Depending on the project and the amount of tolerance required, plastic gears can be the perfect fit. The use of plastic spans the total spectrum of manufacturing from toys to automobiles and huge trucks.
Aluminum gears, like stainless steel and brass, is rust resistant, impervious to moist conditions, and long lasting. This type of gear is usually designed for non-stressful conditions that require dependability. They are usually found in copy machines, toys, and systems that are exposed to the elements.
The general purpose of gears is to change the direction of energy. The use that most of us are aware of is in the transmission of a car where it shifts from one gear to another as the vehicle accelerates. In this case, it is the transfer of horsepower as the vehicle gains speed. The type of gear depends on its purpose. High torque conditions require gears that are able to endure extreme stress and thrust. As the amount of tension decreases, the type of gear will require less strength and lighter materials.
Regardless of the function, gears are contained in a gearbox attached to a shaft and intertwined with another gear. There are several different types of gearboxes depending on the work to be completed. Ground gearboxes, made of stainless steel, titanium, or nickel, are rather common and are used in the aviation industry. When a gear is being designed, the gearbox or enclosure has to be determined during the process.
Several factors have to be considered when determining the type of gearbox. A major factor in the choice is how well the gears teeth mesh. When this occurs properly, the gearbox will have peak performance and be able to withstand any torque placed on it. The teeth of gears perform much like tiny levers as they turn against one another. Efficient meshing enhances performance, eliminates stress, and avoids slippage. This dynamic can be measured using a stationary parametric analysis, which determines the quality of the mesh during a gearing cycle.
Though gears are at the center of the gearbox, around the shafts, that the gears are attached to, are bushings and bearings. Precision gearing is highly dependent on the highest possible quality for these two parts. They need to be properly lubricated and maintained to ensure peak performance. As with all parts, the bearings and bushing should be tested. There are a variety of methods that can be used to ensure they are properly placed and work smoothly.
Bevel gearboxes are used for right angel applications, which are speed reducers with shafts being perpendicular to each other. The configuration of these gears depends on the angle between the two gears which can be 90 degrees or less. These gearboxes usually have two shafts that protrude from them with one or two gears attached to each shaft. As with all aspects of gear technology, the design of the gearbox depends on its final application.
Prior to the invention of the gear, many centuries ago, energy transfer consisted of two wheels being rolled against one another, which created unwanted friction and slippage. The introduction of the gear allowed for the smooth transfer of energy as well as avoiding slippage. This single simple invention has become the center of mechanical technology and is the first consideration in the develop of most devices.