Shim for a turbomachine blade

Abstract

A shim (20) for a turbomachine blade (14), the shim comprising two branches (20A) for coming against bearing surfaces (16A) of the blade rotor (16), and a base part (20B) interconnecting the branches. The shim presents, at least in its branches (20A), a multilayer structure having at least three layers (31, 32, 33) that are fastened to one another and superposed in the following order: a first layer (31) of a first material; a second layer (32) of a second material; and a third layer (33) of a third material that is optionally different from the first material, said first and third materials presenting respective first and third Young's moduluses of values E and E′ at any arbitrary operating temperature in the operating temperature range of the shim, and said second material presenting a second Young's modulus of value lying in the range E / 20 to E / 5 and in the range E′ / 20 to E′ / 5 at said operating temperature.

Description

[0001]The invention relates to shim for a turbomachine blade, the shim being of the type comprising two branches that are to come against the bearing surfaces of a blade root, together with a base part interconnecting the branches.BACKGROUND OF THE INVENTION[0002]The shim can be used with any type of turbomachine whether terrestrial or for aviation purposes (turbojet, turboprop, terrestrial gas turbine, etc.). In the particular circumstance of a bypass, two-spool airplane turbojet, the shim of the invention can be used for the fan blades, or for the moving blades of the low pressure compressor (or “booster”), or for the high pressure compressor, or for the high pressure turbine, or for the low pressure turbine of the turbojet.[0003]In the present application, the axial direction corresponds to the direction of the axis A of the rotor of the turbomachine, and the radial direction is a direction perpendicular to the axis A. Furthermore, unless specified to the contrary, adjectives suc...

AI Technical Summary

Benefits of technology

[0009]An object of the invention is to provide a shim that is more effective than the above-mentioned known shim in terms of performing the “anti-wear” function, so as to provide better protection to the bearing surfaces of the blades and of the disk.

[0016]The multilayer structure of the shim of the invention has the following effects:

[0020]A particular consequence of these effects is to prevent or limit wear phenomena in the bearing surfaces, thereby increasing the lifetimes of blade roots and of disks.

[0021]These effects are reinforced when the second material presents viscoelastic behavior in the operating temperature range of the shim, more particularly for the purpose of damping any dynamic movements of the blade.

Problems solved by technology

When they are repeated, these relative movements, known as slip or as separation depending on their nature, give rise to wear phenomena in the bearing surfaces of the blades or of the disks.

These wear phenomena are naturally penalizing on the lifetime of a turbomachine.

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