How do they make wind turbines?

There is a nice article in American Machinist this week about the production of wind turbines for wind-power machines. It goes into detail about all the work that goes into creating a wind machine, from fabrication to milling.

Many wind turbine component shops process such parts as gear case assemblies, planetary carriers and hubs on horizontal boring mills. These machines, with contouring heads and programmable boring bars, can reduce the number of tools, and tool changes, required to complete parts.

One tool can bore multiple diameters and produce complex part geometries. A contouring head combined with a programmable boring bar can perform as many as nine to ten different operations – atypical for a boring mill. Operations include threading, grooving, turning, contouring, taper turning and more, internally and externally, and rightangle heads and precision rotary tables add capabilities for five-sided part processing in single setups.

The whole article is worth checking out if you're interested in the process of industrial design, fabrication, and milling.

And now... an informative video!

Gearing Advances Drive Air Jellyfish Robot

That's a heck of a title, but I just read an article that lives up to it. It's about how the United States Navy is developing robotic jellyfish that use energy harvesting technology to travel and surveil the oceans for time measured in years. The first prototype--designed by a consortium of universities from around the country--is called AquaJelly.

AquaJelly is an artificial autonomous jellyfish which consists of a translucent hemisphere and eight tentacles for propulsion. AquaJelly's translucent dome houses an annular control board with integrated pressure, light and radio sensors. AquaJelly has a watertight laser-sintered body that houses a central electric motor, two lithium-ion polymer accumulator batteries, the charging control unit and the actuators for the swash plate.

Engineers are currently working on developing actuators that would convert energy from the surrounding ocean into usable energy to power the AquaJelly. I'm a little dubious of how effectively they can carry off such a project since it seems like they're trying to build a sort of perpetual (or very, very long-lasting) motion machine.

University engineers are also working on a similar creature for use in the sky rather the sea. It's called the AirJelly, and its

sole source of power is two lithium-ion polymer accumulator batteries rated at 8V and 400 mA, which can be completely charged in half an hour. It transmits the force to a bevel gear and from there to a succession of eight spur gears, which move the eight tentacles of the jellyfish via cranks. Each tentacle is designed as a structure with Fin Ray Effect. AirJelly is the first indoor flight object with peristaltic drive.

The creature is fairly impressive (if impractical-seeming). I don't know how effective an eight-legged air jellyfish will be at surveying and obtaining information, but I do know that this is one of the most novel applications of gearing technology I've seen yet.

Want to know more about metal casting?

There’s a good piece in the latest Gear Solutions Magazine about metal casting and different types of metals, which is something that’s not solely related to gear manufacturing, but it’s something that underlies just about the entire industry. It’s worth a read.

Sand Casting: This is the oldest known method of producing an intricate casting. Molten metal is poured into a non-permanent sand mold that has been prepared with a pattern. Green sand molds use synthetic sand or sand in its natural or green state, i.e. damp sand still containing moisture. The sand must be cohesive and refractory (withstand heat without fusing), permeable (porous enough to let gases escape), and strong enough to support the weight and cores. Such a cast gear, even with extra care, can only achieve a quality level of A14.

Did someone else think of it first?

Did you know that (among the rest of its apparent plans for World Domination) Google has created a service called Google Patents? With it you can search the United States Patent and Trademark Office (USPTO) library of over 7 million patents and 1 million patent applications.

Google is using the same technology as it uses for Google Book Search; it has converted the entire image database of the USPTO into a text-searchable database. It is, to say the least, a diverting pastime to browse this extensive service. Here are a few interesting gearing patents.

Improvements in gears and gear teeth structures for use in driving assemblies, such as machines, vehicles and the like, wherein the teeth portions of the gears and, in certain instances, other portions thereof, are coated with a hard synthetic diamond material deposited thereagainst as carbon...

A gear-shaped tool (30) having stock removing surfaces (38) is rotated together with a bevel or hypoid work gear (32) in accordance with their respective number of teeth, and the gear-shaped tool 30 is also moved relative to the work gear (32) in the manner of a theoretical generating gear (46)...

A method is disclosed wherein standard generating motions for the production of bevel and hypoid gears are modified by the substantially simultaneous inclusion of additional controlled motions which enable a desired tooth surface geometry to be produced on the gears.

If you're interested in gears specifically or any other manner of thing, Google Patents is a neat resource--for both professional research and recreational browsing.

Gears! What are they good for?

We talk a lot on this blog about gears, and we take for granted that our readers know all about the subject matter. But since we’re getting some new readers, we thought it would be a good idea to cover some gear basics. To start out, a gear is just a part of a transmission device; it helps transmit rotational torque by applying force to another gear or toothed piece of equipment. Gears are found, for instance, in the transmission of your car and, of course, on your bicycle. They allow you to multiply your force or to change the rotational speed or direction of a force.

Gears are extremely useful because of this force multiplication. Since the rotational speed of a gear is in proportion to its circumference and speed of rotation, a larger gear will turn more slowly than a smaller gear with which it’s meshed. Think of bicycle tire spinning: The outside edge of the tire is spinning slower than the inside edge, but both edges are making the same number of rotations. A larger gear has more teeth than a smaller gear, so when the two meshed gears are turning, the smaller gear will have made more revolutions than the larger gear. This relationship is called the “gear ratio,” and it generates the mechanical advantage of gears.

Gear ratio is the relation between the number of teeth on two gears that are meshed.
You can express this relation mathematically. For example, if one gear with 26 teeth is driven by a gear with 14 teeth, the gear ratio is 1/1.86, or 1:1.86. (That is, the mathematical expression of gear ratio is the number of teeth on one gear divided by the number of teeth on the other gear, basically.) A piece of equipment’s gear ratio is used to determine its performance and capability.

(An automobile transmission: Look a those gears!)

Gear ratios are specifically determined by manufacturers of engines and other equipment to achieve a certain result. In some contexts--such as in automobile transmissions--gear ratios can be varied to adapt to the car’s needs at different rates of speed. The lowest gear in a car’s transmission will have a high gear ratio, such as 2:1 or 3:1, which allows the car to achieve a smooth start from a full stop. However, since the engine has to make two or three revolutions for every revolution of the transmission the engine cannot make the car in low gear go very fast in first gear. In second gear, the gear ratio is lower, meaning that the engine does not have to work as hard to give the car additional acceleration. In the higher gears, the gear ratios get progressively lower. These are good for moderate acceleration and reducing the number of engine revolutions needed to keep the car at a comfortable cruising speed. The gears in a transmission, therefore, serve to either magnify or reduce the output of an engine, based on the car’s speed at the time.

We hope that this little post helped to clear up some questions about what exactly gears are and how they function in a practical, day-to-day capacity!