Genesis Partners has developed and tested a non-involute tooth form that projects up to a 40 percent improvement in various physical and performance parameters of a gear pair compared to the equivalent involute. A distinct advantage of this new tooth form is that it utilizes the existing gear manufacturing asset base. Under an exclusive agreement Dontyne Systems has programmed the Genesis Partners source code to not only design and rate Convoloid pairs and compare them directly with involute pairs, but also provide the protocols to easily craft these designs to optimize many of the gear parameters influencing successful gearing applications. The confluence of the well-developed specialties of these two firms provides timely, efficient, and comprehensive analysis prior to the machining, testing and inspection of hardware—a breakthrough in the future of gearing power density and cost reduction.

The relative size reduction for Convoloid over optimized involute equivalent for same ratio and face width translate into large benefits in production cost and power density as well as operating life. Dontyne Systems has completed both design and loaded tooth contact analysis modules for the Convoloid gear form. Parameters such as stress, load, efficiency and transmission error can be calculated. These can be used to investigate the performance of a design including the effect of center distance variation and misalignment. The problems associated with this type of conformal gearing are not as acute as an experienced gear designer might intuitively expect. Potential problems such as stress concentrations, micropitting, and vibration can be treated by surface modification, in the same way as an involute gear form often is, to achieve optimum operation. The software enables the user to quickly establish whether the Convoloid solution is appropriate to provide an advantage over the involute for a given application under specific operating conditions. Further modules to simulate manufacturing and inspection — linking directly to production equipment — are close to completion.

This technology has been aimed initially at the wind turbine industry during its development. As the understanding of the limitations has increased through software analysis, then the confidence in the product applicability has grown such that many industries are ready to investigate the operating characteristics of non-involute designs as never before. This new calculation is exclusive to Dontyne Systems. Genesis Partners will be giving a talk in the Solutions Center on the development and testing of this technology entitled “Convoloid—The Future of Power Density and Cost Reduction,” scheduled for 9/17/2013 at 3:00 PM . The presentation will also include some results from the new analysis software. The potential for this design software or design service can be discussed in more detail at the Dontyne System Booth 1052.

Micro-Erosion: Propagation of Micropitting

The ISO 15144 Method A and B for micropitting have been implemented in Dontyne Systems' Gear Production Suite for some time now. The standard is fairly restricted, only giving indication of the risk of micropitting which could be based over a 16 to 70 hour test. It does not state whether micropitting will continue to develop with time or stop (as will be the case sometimes) and further whether this is actually detrimental to the operation of the gear. This may lead some gears to be scrapped and development programs halted pending redesign when it may not be necessary, leading to costly and wasteful delays. Dontyne has been working with Dave Barnett (Gears Made Easy) to implement a calculation which looks at the longer term micro-erosion (model of the propagation of micro pitting) and the influence on operating characteristics under load. The calculation procedure itself has been has been explained in previous AGMA FTM presentations and more recently in a Voices piece (Gear Technology November/December 2011). The new method has been experimentally validated and it is believed can contribute to the understanding and development of a more complete model of gear behavior for more efficient design and production. Significantly, it can also look at the implications on life due to surface modification. This new calculation is unique to Dontyne Systems and can be demonstrated at the Gear Expo Booth 1052.