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## A NOVEL LEMON SHAPED GUIDE TO MINIMIZE EXCESSIVE RUBBING IN ROTATING MACHINES

In industries, rotating machines are widely used, because rotation offers a great way to transfer power from one point to another and convert motion to different planes by gears, belts, shaft etc. A rotating machine typically includes a rotor, bearings and a support structure. There are critical relations among these components where each component of a system influences the overall dynamic behavior of a machine. For example, rotor-to-guide rub degrades a mechanical system over the years and may even cause fatal accidents earlier. It is, therefore, paramount in industries, to run rotating machines, operating at high speeds smoothly and reliably. The primary reasons of rubbing between a rotor and a guide are due to a manufacturing error, excessive imbalance, misalignment, bearing wear, smaller radial clearance between the rotating shaft and casing, bad assembly, etc. Rub occurs in rotor casing, seals, unlubricated journal bearings, loose rotor guide attached to restrict a large deflection. The problem is prevalent in the industry and demonstrated in several literatures. To deal with this problem, the industry has already been using circular shaped guide to minimize excessive vibration between a rotor and a stator. Although, the circular shaped guide may reduce the vibration, but the rub, between rotor and guide, may still be present, which may lead to the permanent damage of a mechanical system. The lemon shaped guide is not only effective in minimizing rubbing between rotor and stator, but also it suppresses the excessive vibration similar to the circular shaped guide.

The following video shows an experiment on how to minimize rubbing between a rotor and a guide that typically happens in a high speed rotating machine with a newly developed lemon shaped bearing or guide. We see here as the speed goes high, the system enters into its resonance frequency where it vibrates excessively. The lemon/elliptical shaped guide helps prevent the excessive rubbing while the rotor-bearing assembly is in the natural frequency zone. It has been found from our research that the lemon shaped guide minimizes rubbing better than the circular shaped guide where there the rotational speed is very high (https://doi.org/10.1115/1.4043817).

The next video shows an experiment on how to minimize rubbing between a rotor and a guide that typically happens in a high speed rotating machine with a circular bearing or guide. This is a traditional approach, which has been in operation in industries for long. We see in the video, as the speed goes high, the system enters into its resonance frequency where it vibrates excessively. The circular guide helps prevent the excessive vibration while the rotor-bearing assembly is in the natural frequency zone. However, if we notice carefully, the rubbing is still present between the rotor and guide, which deteriorates the system gradually.

A US provisional utility patent (US Patent App. 62/956,833) has already been filed for this design. I am looking for industrial partners or investors if they are interested in investing this product.