Rotary coupling

with overflow oil connection,
max. operating pressure 350 bar

Article no. Connections inputs Connections outputs Ambient
Md max.
max. r.p.m.
NG Weight
445536 6991-21 2 2 -10 - +60 5,0 85 5 2,5
323493 6991-41 4 4 -10 - +60 7,5 48 5 4,2
323519 6991-61 6 6 -10 - +60 14,0 40 5 6,2


Rotary feed-through housing from spheroid graphite iron with radial oil connections 1/4" thd. Rotary piston from nitrided, hardened steel with radial and front oil connections 1/4" thd. The reductions in the face side connections can be use as O-ring connection. Cover from hardened steel with radial 1/8" thd. oil connection for leaked oil discharge.


Rotary couplings transmit flows of hydraulic oil from a stationary machine component to a rotating one. They are located in the rotary axis of a rotating system. The rotary couplings are generally designed for hydraulic systems. To transmit air flows, they have to be filtered, oiled, and free of water. Single-acting and double-acting cylinders can be connected. Each cylinder channel requires a separate connection on the housing and on the rotor.


Because of the high-grade seal packages it is possible to operate at high pressures. Multistrand rotary oil couplings. Long service life. Compact design.


Max. pressure and max. rpm must not occur together. See diagrams.
The rotary couplings must be operated without bending forces. We recommend that you screw the rotating housing with the connections to the clamping fixtures and secure the rotary piston only against twisting. Do not introduce any bearing loads! The line connections to the rotary piston must always be made with hoses. The frictional resistance on the seals is pressure-dependent. This must be taken into account when calculating the drive torque for the rotary table. The rotary couplings are fundamentally designed for intermittent operation.
Special versions available on request. See diagrams for minimum and maximum load data.