Internal gears have straight teeth along the internal diameter rather than pointing outward, which mesh with one or more small pinions inside the gear, and they transmit rotary motion between parallel shafts that turn in the same direction. Internal gears are usually… Learn More
Gears are available in a variety of materials, including stainless steel, cast iron, brass, and plastic, depending on application. There are several other factors to consider when selecting the appropriate gear for an application. The gear’s outside diameter is the longest linear distance across a gear. The bore diameter is the distance across the hole located in the center of a gear, where the mounting shaft will be inserted. The hub diameter is the distance from one tip of the shoulder (the hub) to the other. The thickness is the distance measured from the tip of a gear tooth to the gear’s bore or base (for a gear rack). The number of the teeth refers to the number of teeth around a gear. The pitch, also called the diametral pitch, is the number of teeth divided by the pitch diameter, and it can also serve as a guide for tooth size.
Internal gears are combined with spur gears to form planetary gear drives, which are commonly found in elevators, cranes, and automotive applications.