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Diaphragm Coupling

Simple and high-performance coupling for higher speed/larger capacity
This diaphragm coupling originally developed for helicopter drive shafts has been redesigned for general industrial purposes.
The diaphragm part employs a special profile processing (characterized by high torsional rigidity, flexible against bending/compression) to achieve high torque transmission.
This product has marked a maximum speed of 100,000 rpm and maximum torque of 2,700 kN-m in actual applications, and has gained good reputation in various fields as an ideal coupling (i.e. high speed/high load torque transmission, light weight, and no lubrication).
Characterized by the capacity to flexibly absorb misalignments (low bearing load), this diaphragm coupling has been increasingly recognized to be essential for turbines and compressors of ever higher speed/larger capacity, as well as other rotating equipment for commercial power generator, steelmaking machines, equipment for vessels, and aircraft, etc.


  • Special diaphragm shape enables to transmit a large torque, low load on the bearing
  • Simple structure ensures easy installation/removal, lightweight
  • Optimum for high speeds (100,000 rpm max.)
  • Having no movable/frictional parts, this coupling does not require lubrication nor have noise, vibration, backlash, change in dynamic balance.

Product specification example

 Model 66

  • Special low alloy steel used for the diaphragm
  • Main applications: general-purpose pumps, precision machine tools, general-purpose machines, main engines/auxiliary equipment for vessels, power generator

Model 67/74   Model 99/100           Complies with API 671, high-speed/high-torque specifications

  • Model 67/99: Complies with low-speed specifications of the API 671 standard
  • Model 74/100: Complies with mid-/high-speed specifications of the API 671 standards
  • Model 67/74: special low alloy steel used for the diaphragm
  • Model 99/100: special pre cipitation-hardening stainless steel used for the diaphragm
  • Main applications: gas/steam turbine driving systems, compressors, large combined power generation system
Applicable ranges shown in the product introduction are limit values for each standard material.
Applicable ranges, performance data and figures can serve only as a guide for selection and therefore in actual use there will be some cases where general specifications cannot be applied due to unknown factors or constraints.
Please check the applicability before use.
The contents are subject to change without notice for improvement.


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