A diaphragm coupling is a high-performance, flexible coupling that transmits torque between two shafts while accommodating misalignment (angular, parallel, and axial) through the flexing of one or more thin, metallic discs (diaphragms). They are a premier choice for demanding applications where precision, reliability, and high speed are critical.
Key Characteristics & Advantages
High Performance and Precision: They provide zero backlash and highly torsionally stiff power transmission. This means they don't introduce rotational lag or "wind-up," making them ideal for precision motion control systems (e.g., CNC machines, robotics).
Maintenance-Free: Unlike gear couplings, they require no lubrication. They have no moving parts that wear against each other, leading to a long service life with minimal maintenance.
High-Speed Capability: Their balanced, all-metal design allows them to operate efficiently at very high rotational speeds (often tens of thousands of RPM) without issues like flinging lubricant or imbalance.
Excellent Misalignment Capacity: They can accommodate all three types of misalignment:
Angular Misalignment: The diaphragms flex in a "coning" motion.
Parallel Misalignment: The diaphragms stretch and compress.
Axial Misalignment: The diaphragms can accommodate shaft movement along the axis.
Torque Transmission: They are capable of transmitting very high torque for their size and weight. Torque is transmitted through the diaphragm material itself, which is typically high-strength stainless steel.
How It Works (The Basic Principle)
The coupling consists of two hubs (connected to the shafts) and a center member (spool), all connected by these thin, flexible diaphragms. The diaphragms are bolted alternately between the hub and the center member.
When torque is applied, it is transmitted from the first hub, through the first diaphragm, to the center spool, through the second diaphragm, and finally to the second hub. Misalignment is accommodated by the elastic bending (flexing) of the diaphragms rather than by sliding or rolling parts. This flexing occurs within the metal's elastic limit, meaning it returns to its original shape, preventing permanent deformation.
