1. Overview of Couplings

2. Key Types of Couplings and Their Application Scenarios

2.1 Rigid Couplings

• Common Types: Sleeve couplings, flange couplings, clamp couplings.

• Application Scenarios: Ideal for systems where shafts are precisely aligned (misalignment ≤ 0.1 mm) and operate under stable loads. Typical applications include precision machine tools, small pumps, and gearboxes with strict alignment requirements.

• Note: Requires accurate installation and alignment; otherwise, additional stress will be imposed on bearings and shafts, accelerating wear.

2.2 Flexible Couplings

• Common Types and Applications:

• Elastomeric Couplings (Rubber/Polyurethane): Such as jaw couplings, tire couplings. They offer good vibration absorption and moderate misalignment compensation (radial misalignment up to 0.5–2 mm, angular misalignment up to 1–3°). Suitable for general machinery like pumps, fans, conveyors, and electric motors in industrial production lines.

• Metal Flexible Couplings: Including diaphragm couplings, bellows couplings. Made of high-strength metal (e.g., stainless steel, alloy steel), they feature high torque capacity, corrosion resistance, and precise transmission. They can compensate for small misalignments and are suitable for high-speed, high-precision systems such as aerospace equipment, gas turbines, and precision servo motors.

• Universal Couplings: Designed to handle large angular misalignments (up to 30–45°), they are commonly used in automotive drive shafts, agricultural machinery, and construction equipment where shafts are not in the same plane.

• Overload Protection Couplings: Equipped with torque-limiting mechanisms (e.g., shear pins, friction plates), they disconnect the transmission when torque exceeds a set value, protecting key components from damage. Applied in crushers, extruders, and other equipment prone to overload.

3. Core Principles for Selection of Couplings

3.1 Torque and Speed Requirements

• Calculate the nominal torque of the system (including rated torque and peak torque during startup) and select a coupling with a rated torque 1.2–2.0 times the nominal torque to ensure overload capacity.

• For high-speed applications (rotational speed > 3000 rpm), prioritize lightweight, balanced couplings (e.g., diaphragm couplings) to avoid resonance and ensure dynamic stability.

3.2 Shaft Misalignment Compensation

• Evaluate the expected misalignment (radial, angular, axial) between the two shafts. For large misalignments, choose flexible couplings with strong compensation capabilities (e.g., tire couplings, universal couplings); for precision systems with minimal misalignment, rigid couplings or metal flexible couplings are preferred.