Safran has been granted a patent for a turbomachine with a counter-rotating turbine for aircraft. The turbomachine includes a mechanical reduction gear with an epicyclic, planetary-type gear train. The gear train features a planet carrier attached to a stator housing, which is secured by an annular part with an integrated circuit for conveying lubrication oil to the planet carrier. GlobalData’s report on Safran gives a 360-degree view of the company including its patenting strategy. Buy the report here.
According to GlobalData’s company profile on Safran, photovoltaic drones was a key innovation area identified from patents. Safran's grant share as of September 2023 was 65%. Grant share is based on the ratio of number of grants to total number of patents.
Counter-rotating turbine with mechanical reduction gear for turbomachine
A recently granted patent (Publication Number: US11773771B2) describes a turbomachine with a counter-rotating turbine for aircraft. The turbomachine includes a first rotor connected to a first turbine shaft, rotating in one direction, and a second rotor connected to a second turbine shaft, rotating in the opposite direction. The first rotor consists of turbine wheels placed between the turbine wheels of the second rotor.
The turbomachine also features a mechanical reduction gear with an epicyclic gear train of the planetary type. This gear train includes a sun gear driven by the second shaft and a ring gear driven by the first shaft. A planet carrier, attached to the stator casing of the turbomachine upstream of the counter-rotating turbine, is connected to the gear train.
The patent introduces an annular part with an elongated shape that connects the planet carrier to the stator casing. This part contains an integrated circuit designed to convey lubricating oil from the upstream end to the planet carrier. The annular part is described as one-piece and includes a frustoconical section and a cylindrical section. The frustoconical section connects the upstream end to the cylindrical section, which is then connected to splines for coupling to the planet carrier.
The integrated circuit within the annular part includes an internal annular cavity at the junction between the frustoconical and cylindrical sections. Oil inlet pipelines, formed in an extra thickness or in bosses in the frustoconical section, extend upstream from the annular cavity to orifices on the upstream face of the upstream end. Oil outlet pipelines, formed in an extra thickness or in bosses in the cylindrical section, extend downstream from the annular cavity to orifices on the external cylindrical surface of the part, upstream of the splines.
The cylindrical surface of the annular part is located between two annular grooves configured to receive annular seals. Some of the pipelines within the integrated circuit are elliptical in cross-section. The splines of the annular part are separated from the rest of the part by an annular weld bead.
The patent also includes a method for manufacturing the annular part. The method involves producing the upstream portion of the part using additive manufacturing, including the upstream end and the integrated lubricating oil conveying circuit. The downstream portion of the part, which includes the downstream end and splines for coupling to the planet carrier, is produced through forging. The upstream and downstream portions are then welded together.
Overall, this patent describes a turbomachine with a counter-rotating turbine and a mechanical reduction gear, featuring an annular part with an integrated circuit for conveying lubricating oil. The design and manufacturing method outlined in the patent aim to improve the efficiency and performance of the turbomachine.