A diaphragm coupling is a high-performance flexible power transmission component designed to connect two rotating shafts in mechanical systems, facilitating efficient torque transfer while addressing common operational challenges like shaft misalignment and vibration. Unlike conventional couplings that depend on elastomeric materials or mechanical contact (such as gear or jaw couplings), it leverages one or more thin, flexible metal diaphragms as the core torque-transmitting element—eliminating the need for lubrication, minimizing wear, and ensuring long-term reliability.
At its core, the diaphragm coupling consists of several key parts that work in synergy. The diaphragms themselves, typically made from high-strength metals like stainless steel or titanium, are thin, disc-shaped or bellows-like structures. Their flexibility allows them to bend slightly to accommodate three types of shaft misalignment: angular (when shafts are not colinear), parallel (when shafts are offset horizontally), and axial (when shafts move toward or away from each other) — all without compromising torque transmission efficiency.
Attached to the diaphragms are shaft hubs, which serve as the connection points to the driving and driven shafts (e.g., from a motor to a pump or generator). These hubs are secured to the shafts via methods like keyways, set screws, or shrink fits, ensuring a tight, slip-free connection. Some diaphragm coupling designs also include an optional spacer — a rigid tube that separates the two hubs. This spacer design simplifies maintenance of connected equipment, as it allows for easier removal or inspection of components without fully disassembling the coupling or moving the shafts.
Diaphragm couplings excel in high-speed, high-torque applications where precision and durability are critical, such as in aerospace, automotive, industrial machinery, and power generation. Their all-metal construction resists extreme temperatures, chemicals, and harsh environmental conditions, while their lubrication-free operation reduces maintenance costs and downtime. Additionally, the diaphragms help dampen vibrations and absorb shock loads, protecting sensitive equipment from damage and extending the overall lifespan of the mechanical system.
