What is Power Transmission?

Huyett stocks and manufactures a wide range of fasteners for the PT/MC Industry that securely hold or interlock components to keep your machines and manufacturing lines moving. The following is a brief introduction to some basic power transmission concepts.

Huyett’s plain carbon and stainless steel parts are RoHS compliant.

In its simplest form, power transmission is the transfer of energy from one place to another where it is then put to work. This transfer of power, also known as mechanical work, is a system of integrating gears and shafts that provide speed and torque conversion using basic principles of physics. To the best of our knowledge, the mechanical gear — a rotating machine part with cut teeth or cogs, which meshes with another toothed part in order to transmit torque — was invented sometime around 300 B.C. by Greek mechanics in Alexandria. In the centuries since, this simple concept has enabled the invention and evolution of all sorts of machinery and vehicles.

Adjacent, interlocked gears rotate at different speeds in opposite directions, with the smaller gear rotating more quickly.

Similarly, sprockets are profiled wheels that connect with a chain or track. They differ from gears in that they do not touch. In this configuration, both sprockets turn in the same direction as the chain that connects them.

Special gear and sprocket configurations including spur gears, worm drives, helical gears, beveled and mitered gears, and rack and pinion gears are used to transfer power from one axis to another.

The push or pull on an object that results in a change of shape, speed, or location.

Friction is a force of resistance that acts in the direct opposition of another force to oppose any attempt to initiate motion. Friction must be consistently overcome in order for motion to occur.

Just as force is a push or a pull, torque is more of a twist. It is the tendency of an object to rotate as a result of a force being applied at some distance away from the center of rotation. For instance, pushing or pulling on the wrench below applies force that creates torque to loosen or tighten a nut on a bolt.

Gears are connected to metal shafts that rotate to produce torque. Sometimes gears are permanently welded to a solid shaft.

More often, a keyed shaft and a gear with a key way are joined using a piece of key stock (or a machine key) to produce a versatile, reusable assembly that can be disassembled and reassembled for repair or maintenance.

Should a power transmission component become damaged or break from stress and wear, the potential for catastrophic and collateral damage is enhanced in welded assemblies because of the linkage of the components.

In normal operation, a keyed assembly allows primary gears and drive shafts to turn together.

However, if forces exceed design limits, the machine key may shear, preventing damage to other components.

Inexpensive machine keys effectively act as safety stops to protect expensive mechanical components.

Key stock and machine keys must be made to proper specifications for each application. Design Engineers must account for load, material, and heat treatment to prevent placing users in potentially dangerous situations or subjecting machine components to stresses that could result in property damage if parts shear.