A worm gear is a mechanical arrangement consisting of a spiral-threaded shaft butted against a toothed wheel, resembling a standard spur gear. The threaded shaft, also known as a worm, acts as the driving element, imparting motion to the wheel as the rotational power from the worm is transferred in a 90o plane.
Worm gears are typically used for their high gear reduction ratios. It is common for standard worm gears to achieve reduction ratios ranging from 20:1 up to 300:1. This attribute makes worm gears ideal for applications that require reduced rotational speeds or significantly increased torque. By comparison, it would take multiple conventional gearsets to achieve the same levels of reduction.
Worm gears also have another useful characteristic—they possess a natural self-locking feature by design. The worm can easily turn the gear wheel, but the gear wheel cannot turn the worm, thus preventing reverse movement.
How to Make Bronze
Bronze is one of the most commonly used alloys for worm gears due to the material’s desirable mechanical properties. The term “bronze” covers many copper alloys, though the final product ultimately depends on the other material contained within the alloy. For example, using nickel creates copper-nickel alloys, or using zinc creates brass. Bronze, on the other hand, is most often created by creating a copper alloy with tin or aluminum.
At Accurate Specialties, we utilize a variety of alloys to meet our client’s specific requirements. Typically, for worm gears, we recommend tin bronze (C91700) and aluminum bronze (C95400 and C95500) due to their relatively high strength, and superior fatigue, friction, and wear resistance.
The process of making bronze involves first heating the copper element to a specified temperature. Once the copper reaches a molten state, predetermined amounts of alloying compounds (such as aluminum or tin) are added to the molten copper. The molten alloy mix is then poured into bronze casting dies for the gear components and allowed to cool.
Typical Bronze Worm Gear Applications
The high torque output of worm gears makes them suitable for heavily loaded machinery. Some of the most common applications for worm gears include:
- Movable bridge components
The controlled and powerful motion of worm gears are ideal for inducing movements in large and heavy bridge structures.
- Elevators, lifts, packaging equipment, and conveyors
Worm gears are used to provide the torque needed to transport heavy loads from one point to another. The non-reversible properties of this gear also act as a secondary safety braking system.
- Heavy-duty construction equipment and trucks
Heavy vehicles often use a worm gear differential for additional power. Depending on the action of the vehicle, different amounts of torque may need to be delivered to each wheel. Worm gears are used to provide the necessary torque that governs each wheel’s performance.
At Accurate Specialties Inc., we provide custom worm gear manufacturing services for numerous applications in almost any industry. Our technical team will work with you to help determine the best alloy for your unique specifications.