subject: All about Gears [print this page] All about Gears All about Gears
Gear is one kind of mechanical parts. It can be widely used in the industry. A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque.
There are various types of gears such as spur gears, helical gears, double helical gears, bevel gears, worm gears, etc. Different types have their unique characteristics. Some kinds of gears are discussed below.
An external gear is one with the teeth formed on the outer surface of a cylinder or cone. Conversely, an internal gear is one with the teeth formed on the inner surface of a cylinder or cone. It is rather easy to understand this kind of gear, and if given pictures about the external gear or the internal gear, we may have the ability to distinguish them.
Spur gears, the simplest type of gear, consist of a cylinder or disk. Their form is not straight-sided, thus, the edge of each tooth is straight and aligned parallel to the axis of rotation. Only gears fit to parallel axles can they rotate together correctly.
Compared to spur gears, helical gears are more refined. The leading edges of the teeth are set at an angle and not parallel to the axis of rotation. Since the gear is curved, this angling causes the tooth shape to be a segment of a helix.
Double helical gears, obviously, have more advantages than helical gears. They have two sets of teeth that are set in a V shape which can solve the problem of axial thrust presented by helical gears. But they also have some disadvantages compared to helical gears. For instance, it is more difficult to manufacture double helical gears due to their more complicated shape.
A bevel gear is shaped like a right circular cone with most of its tip cut off. They are largely used in the hafts from the main shaft to the back shaft. Another kind of gears is called worm gears. They are often meshed with an ordinary looking, disk-shaped gear, which is called worm wheel. Worm gears are mainly used for wheel gear in motor vehicles.
There is no doubt that many other kinds of gears are also very useful in our industry. Gears discussed above are more commonly used. To learn some basic information about them is rather necessary.
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