Sealing the fastening of a bearing support in a turbomachine

Abstract

A turbomachine including a shaft guided in an upstream bearing and a downstream bearing, the upstream bearing being carried by a first annular support that is fastened by bolts to a casing via a second annular support that carries the downstream bearing, wherein the ends of the fastener bolts are covered by an annular cover sealingly fastened to the second support or to the casing.

Description

TECHNOLOGICAL BACKGROUND OF THE INVENTION[0001]A bypass turbomachine includes a fan arranged at its upstream end and driven in rotation by a shaft that is guided by upstream and downstream bearings carried by respective first and second annular supports. The upstream bearing is carried by the upstream end of the first support whose own downstream end includes a plurality of orifices distributed around its circumference, thereby enabling it to be fastened by bolting to a radially outer portion of the second support, which is in turn fastened by bolting to an intermediate casing situated downstream from a low-pressure compressor.[0002]The downstream end of the first support includes an annular rim formed with a plurality of notches that receive the upstream portions of bolts for fastening the first support to the second support. These notches open out into cavities machined in the rim of the support for receiving the heads of the bolts. Washers are engaged on the bolts to form continu...

AI Technical Summary

Benefits of technology

The present invention provides a simple and effective solution to avoid the drawbacks of prior art turbomachines. It involves using an annular cover to cover the ends of bolts and prevent debris from escaping into the inter-bearing enclosure. The cover is held in position by a cylindrical rim and includes a sealing ring to prevent oil from escaping via the bolts. The cover is made of a material with a similar coefficient of expansion to the second support and casing. The invention also provides an annular sealing cover with a U-shaped section and a cylindrical rim for sealing the connection between the first and second supports. The cover can be made of titanium or a composite material.

Problems solved by technology

Nevertheless, that type of fastening presents several drawbacks.

Firstly, making cavities in the downstream rim of the first support is lengthy and difficult.

Furthermore, the bolts mounted in the notches of the first support are not retained until the second support is in place, thereby complicating the assembly process.

Thus, in the event of a blade being lost, the resulting unbalance gives rise at the first support to a traction force on the fastener bolts, which are designed to break when the applied load exceeds a predetermined value.

Nevertheless, locating these bolts inside the first support leads to bolt debris being ejected into the inter-bearing enclosure, and that can damage the upstream and downstream bearings and other parts located therein such as enclosure de-oilers, oil nozzles, etc.

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