Deublin's Bearingless Rotating Union

During the machining process, modern machine tools use coolants, minimum quantity lubrication or compressed air for blowing out the chips in case of dry machining depending on the type of material and production task.

Contrary to the past when the work piece was simply "flooded" with coolant, the medium is today transported through the spindle and tool to the tool tip in a well directed way. This procedure calls for a rotating union at the end of the spindle, the function of which is to transfer the medium from the stationary supply lines to the fast rotating spindle.

These rotating unions are independent units.

They are then called "bearingless rotating unions" or "sealing cartridges".

The current development of the bearingless rotating unions shows two tendencies:

1. Miniaturisation

Constantly rising speeds initially caused to develop bearingless rotating unions whereby masses have already been saved.

But modern machining centres must feature even shorter changing times and movement around one or several axes with the highest precision. Accordingly, the machine engineer has to struggle with each half a gram of weight. If mass is saved in the area of the spindle, drives can be more compact, steady-state effects of masses can be reduced and energy can be saved.

DEUBLIN actively supports this approach by miniaturising the rotating unions, i.e. consistent reduction in size of the components. It goes without saying that this does not only mean a mere reduction in size, as the user expects the familiar precision and performance, but research regarding the limits of feasibility (see image 1): Reduction of masses without waiving stability, maximum service life and efficiency.

No easy task for design and materials research!

2. Individualisation

Under the casing of a machining centre you find different geometries of drive units which vary from manufacturer to manufacturer. In addition, you encounter confined space or even shortness of space.

In order to allow the design of a high-performing system, DEUBLIN constantly works on individual housings for rotating unions (see image 2). These special designs are adjusted to the geometry and serve the ideal installation of the component in the machine. This harmonisation does not only entail benefits for the machine engineer but also for the user, as it also has positive effects on the maintenance, because, here, the time required for "disassembly - maintenance - assembly" is of great significance. An adjusted design effectively reduces the time required for these working steps.

Accordingly, the two aspects "miniaturisation & individualisation" are the main reason why for DEUBLIN the "bearingless rotating unions" are a family, but in the end each machine manufacturer obtains its customised rotating union. A close cooperation with machine engineers, flexible and performing design and production methods permit the common progress for the benefit of the user.