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FK 7 DMS
ESB / ESW /
DSB / DSW

fk 7 DMS

double laminar retaining rings with centrifugal force protection

FK 7 DMS double laminar retaining rings with centrifugal force protection

These rings can be used for rotation speeds that “FK 7 DSW” retaining rings cannot cope with.

Advantages of the double-wound laminar retaining rings:

  • Roundness of the closed helix over 360° ensures firm contact with the groove base and full circumferential closure

  • Uniform dynamic weight during rotation
  • Higher axial load capacity compared to the “FK 7 ESB” and “FK 7 ESW” single wound ­ laminar retaining rings

Ring materials

Steel Grade Spring resistant up to Hardness Value Surface Protection Surface Colour
C75 max. +300°C On request1) Oiled Varies 2)
C60S max. +300°C On request1) Oiled Varies 2)
51CrV4 max. +400°C On request1) Oiled Varies 2)
1.4310 max. +450°C On request1) Bright and dry Varies 2)

1) Varies depending on the type of thermal treatment! Hardness values depending on ring cross-section, measured in Rockwell HRA or HRC.

2) The surface colour can vary depending on the type of thermal treatment from silber/bluish to brownish/black.

Permissible peripheral speed
Please note: When making enquiries or placing orders, please specify the exact bore diameter “D1”, operating temperature and rotational speeds!

Running and assembly tests:
Before our laminar rings are used in series production, running and assembly tests must always be carried out under operating conditions to determine whether the retaining rings can withstand the required stress.

Axial load 3)

Axial load 3):
In order to determine the axial load capacity of the retaining rings, shear tests must be carried out under operating conditions. If there are uncontrollable axial impacts between the surrounding components and the laminar rings during operation (coupling effect) or extreme vibration of the components, the secure position of the retaining rings in the groove cannot be guaranteed.

FK 7 DMS ring 4)

Order information 4):
For enquiries and/or orders, the ring diameter specification must correspond to the shaft diameter “D1” exactly.

All dimensions in mm, *reinforced ring design
Note: Please refer to the information on pages 13, 62, 63, 64 and 65 (questionnaire).
All dimensions in mm, *reinforced ring design

Important note:
If there are uncontrollable axial impacts of the surrounding components against the laminar rings during operation (coupling effect) or extreme vibration of the shafts, the secure position of the "FK 7 DMS" rings in the groove cannot be guaranteed. In addition to the stated max. permissible shaft rotation speed, installation and long term run tests must be performed under operating conditions.