What Is A Bushing Chain?

I. Core Structure: 4 Key Components

1. Inner/Outer Link Plates: Serving as the "framework" of the chain, they are usually stamped from high-strength steel and distributed symmetrically on both sides. They bear the tensile load of the chain and ensure structural rigidity.

2. Bushings: Cylindrical metal parts that form an interference fit (tight fixation) with the inner link plates. As the core rotating carrier of the chain, they have a hollow interior to accommodate the pins.

3. Pins: Inserted inside the bushings, their two ends also form an interference fit with the outer link plates, while a clearance fit is maintained between the pins and bushings. This design allows flexible relative rotation between the pins and bushings, reducing transmission resistance.

4. Rollers (Optional): Some bushing chains are equipped with rollers on the outer side of the bushings (called "bushing chains with rollers"). The purpose is to convert the "sliding friction" between the chain and sprockets during meshing into "rolling friction", reducing wear. Those without rollers are called "pure bushing chains", which are suitable for scenarios where rollers are prone to damage (e.g., conveying sharp materials).

II. Core Characteristics: Advantages and Limitations

1. Main Advantages

• Simple structure and low cost: Compared with roller chains, it lacks the "roller" component, resulting in a simpler manufacturing process. Its weight can be reduced by approximately 30%-40%, and the procurement and maintenance costs are lower.

• Good wear resistance: For the same pitch, the pin diameter of a bushing chain is usually larger than that of a roller chain. Additionally, the contact area between the pin and bushing is wider (pressure distribution is more uniform), leading to slower wear during long-term transmission. At high speeds, lubricating oil can easily enter the gap between the pin and bushing, further improving wear resistance.

• Adaptability to harsh environments: The roller-free design reduces the risk of jamming by foreign objects (such as dust and debris). Moreover, some models can work for a short time without lubrication or with low lubrication, and their tolerance to polluted and humid environments is better than that of ordinary roller chains.

2. Main Limitations

• High friction and noise: Pure bushing chains rely on "sliding friction" when meshing with sprockets (this can be improved with roller-equipped models). The transmission noise is higher than that of roller chains, and long-term high-speed operation may cause wear on the sprocket tooth surfaces.

• Not suitable for high-speed/impact scenarios: Due to the characteristics of sliding friction, the transmission efficiency of bushing chains decreases as the speed increases. They also have weak impact resistance, so they are generally used in medium-low speed (usually not exceeding 5 m/s) and stable load transmission scenarios.

III. Typical Application Fields

• Industrial transmission: Such as timing transmission for high-load diesel engines in automobiles, auxiliary transmission for machine tool spindles, and output-end transmission for small reducers.

• Material conveyance: Such as ore transportation in underground mines, grain transportation in agricultural machinery, and short-distance handling of raw materials (e.g., limestone, steel slag) in cement/steel plants.

• Lifting and hoisting: Such as lifting devices for forklifts, counterweight traction for small cranes, and lifting mechanisms for warehouse shelves.

IV. Common Specifications and Standards