rotary couplings: 1 to 6 passages
rotary valve couplings: loading and unloading in one or two stations
Rotary couplings transfer liquid or gaseous media from a stationary to a rotating or swivelling machine part.
The most important fields of application are:
• Swivelling fixtures which cannot be connected by hoses.
• Rotating fixtures that rotate with a determined number of rotations.
• Rotary indexing tables that move in one direction of rotation more than 360 degree.
• Machine tables with swivel movements in both directions.
The oil supply at the housing is made by radial pipe threads that end in circular slots of the rotary piston. From there, the hydraulic oil is led upwards through axial bore holes. The pipe connection at the rotary piston can optionally be effected radially or axially.
Alternatively, a manifold-mounting type with O-ring seals is available.
The starting torque is reduced by the following measures:
• The rotary piston is supported by ball bearings.
• The running surfaces for the seals are nitrated, ground and polished.
• The special seals have low friction and are abrasion resistant.
A radial shaft seal protects the interior against dirt and coolants.
At the leakage port the little leakage can be led away in a controlled manner.
Fixing is made precisely in axial direction at the housing or at the flange of the rotary piston. The firmly-screwed component can be connected with pipes. To compensate the torque, the other part is connected to an anti-rotation key that offers sufficient freedom of motion and avoids forced conditions as well as axial forces. That is the reason why also here high-pressure hoses have to be used instead of pipes.
The leakage port at the housing must not be closed to avoid malfunctions.
As hydraulic medium HLP as per DIN 51524-2 is prescribed. For the use of other media please contact us.
The diagrams on the data sheets show the starting torque and the admissible continuous number of rotations as a function of the operating pressure.
If the rotary coupling is operated at the limit of performance (pressure + number of rotations), pay attention to sufficient supply of cooling air (see Technical characteristics).
A prerequisite for pneumatic use is oiled compressed air free from water. Thus, numbers of rotations up to 10 rpm are possible. A continuous operation with constant high number of rotations is not admissible, because the seals will become too hot for lack of lubrication.
Mixed use of the individual passages is possible, e.g. air – oil – oil - air:
Please note the following:
1. The leakage of high-pressure seals can enter into the adjacent air passage.
2. If the hydraulic pressure is lower than the air pressure, air diffuses into the adjacent hydraulic passage and this can lead to malfunctions (air in oil).
Therefore, we recommend to separate the different media by means of an intermediate leakage passage.
Rotary valve couplings are used if several fixtures have to be supplied on rotary indexing systems. Provided that clamping and unclamping will be made always in the same place and the fixtures are arranged in a uniform way on the rotating plate.
Clamping and unclamping is made by 1off or in the case of double-acting cylinders by 2 off 3/2 directional control valves, which are arranged outside the rotating system. Since in the unclamped position there is a continuous leakage to the return line, we recommend to use an accumulator for applications with operating pressures of up to 200 bar, for applications with operating pressures exceeding 200 bar an accumulator is required.
Rotary valve couplings must only be operated with hydraulic oil. The rotary coupling has to be connected to the power unit on all levels to ensure sufficient lubrications of the seals.
at an indexing machine with 12 stations
with 8 stations for single-acting swing clamps
Application in a multiple-spindle machine with for stations for machining of aluminium covers. The four not required ports of the rotary valve coupling are plugged.
Trunnion bearing with hydraulic locking and integrated
oil supply through rotary valve coupling
Rotary valve coupling in combination with an automatic coupling system