Compression ridge storage

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Helical gearing with pressure ridge bearing. The pressure combs (blue) on the pinion (dark, small) work with the thrust rings (yellow) on the wheel (light, large). The cone angle is shown exaggerated.

A pressure storage comb serves to axial force transmission between parallel rotating shafts in gearboxes . Mainly the parasitic axial component of the toothing force is conducted in helical gears or the compressor thrust in gear compressors.

construction

A pressure comb bearing consists of a pressure comb and a thrust ring.

A disc on the high-speed shaft, the outer diameter of which protrudes beyond that of the pinion , is called a pressure comb . The thrust ring is usually ground on the slow running shaft on the face of the wheel under the tooth root , but it can also be built separately as a free-standing disk. The running surfaces are tapered (taper angle ) so that a convergent gap is created in the covered area, which, together with the transmission oil, enables a hydrodynamic support film to be built up. The contraformal contact is assigned to the area of elastohydrodynamics . Since the lubrication gap is close to the pitch circle of the toothing, where the peripheral speed of the wheel and pinion is the same, the hydrodynamically effective speed (sum of the peripheral speeds) is high and the differential speed is close to zero. The former means high load-bearing capacity, the latter a low power loss compared to roller or plain bearings in which one contact partner is stationary.

Usually the high-speed shaft is floating and the slow one is fixed-loose in order to enable automatic adjustment of the lubrication gap. The pressure comb disk is mounted as an additional component and is not manufactured integrally with the gear so as not to hinder the cost-effective hobbing of the toothing.

history

The compression ridge bearing was patented in 1922 in the context of helical gearing. In the following, however, it was only used in practice to increase the efficiency of geared compressors, i.e. in an application with comparatively high speeds and few start-up processes. Only in the last few years has the technology been used in other areas of application, e.g. B. in transmissions for commercial vehicles, rail vehicles or wind turbines.

Advantages and disadvantages

Comparison of the flow of the axial force caused by helical gearing in a conventional bearing (left) and a compression ridge bearing (right). The compression ridge bearing is designed so that it only works in one direction of rotation.

advantages

disadvantage

  • additional component
  • Wear at very low speeds before full lubrication is achieved (start-up process, see Stribeck curve )
  • no standardized analytical design process available; Use of specialized numerical calculation tools necessary

Individual evidence

  1. ↑ Patent application DE000000401652A: Spur gears with single-sided helical teeth . Registered on April 25, 1922, published on September 6, 1924, applicant: Brown, Boveri & Cie ( online at depatisnet.dpma.de ).
  2. ^ A b Franz-Josef Joachim, Norbert Kurz, Bernd Somschor: Pressure comb technology in vehicle transmissions . In: Plain and roller bearings: design, calculation, use; Veitshöchheim conference, March 3 and 4, 1998 . VDI reports 1380. VDI-Verlag, Düsseldorf 1998, ISBN 3-18-091380-0 , p. 279-312 .
  3. ↑ ZF Friedrichshafen AG: ZF helical axle drives - added value for the Moscow, St. Petersburg and Baku metro . February 23, 2017 ( zf.com ).
  4. ↑ Dirk-Olaf Leimann: Hansen 13.2 / 16.8 MW single stage technology gearbox for next generation high speed gear box design for wind turbine application: Low tonality gear design and new bearing arrangement solution . In: International Conference on Gears (VDI reports) . tape 2 . VDI-Verlag, Düsseldorf 2010, ISBN 978-3-18-092108-2 , p. 1053-1062 .
  5. ↑ a b Marcel Heß: Use of pressure combs to increase the efficiency of helical gears . 1st edition. Papierflieger Verlag, Clausthal-Zellerfeld 2018, ISBN 978-3-86948-624-6 , doi : 10.21268 / 20180403-090318 ( tu-clausthal.de ).
  6. ^ Daniel Thoden: Elasto-hydrodynamic lubrication of pressure combs . In: Messages from the Institute for Mechanical Engineering at Clausthal University of Technology . No. 31 , 2006, ISSN  0947-2274 , p. 23–26 ( tu-clausthal.de [PDF] - the use of the Dowson-Higginson calculation method for the cylinder-cylinder contact is not recommended for taper angles smaller than 1 °).