FR2624786A1 - PROCESS FOR MANUFACTURING A LEFT-SHAPED ROTOR BLADE IN SPACE USING RESIN IMPREGNATED FIBERS - Google Patents

Abstract

A method of fabricating a left-in-space rotor blade by surrounding a core with a resin impregnated fiber material is disclosed. The problem to be solved consists in allowing simple and rapid manufacture as well as an action on the properties of the blade. The method is characterized in that by means of a pressure roller 11, strands of fibers 9 impregnated with coating resin are pressed against the core and the coating resin is cured immediately after pressing in a precuring plant. 15 coupled with the pressure roller 11. The invention is particularly applicable to propeller blades of the "prop fan" type.

Description

"Process for manufacturing a left-handed rotor blade in space

using fibers

impregnated with resin ".

  The subject of the invention is a method for producing a left-handed rotor blade in space by surrounding a core with a

fibers impregnated with resin.

  The construction elements made with fibers have become increasingly important because of their exceptional properties. Their low density, high tensile strength and relatively simple shaping allowed their applications to penetrate into areas that previously were reserved for metallic materials. Thus, we have come to use fiber-reinforced materials also in aeronautics, among others, for applications as rotor blades with high dynamic loads and

  for propellers or propeller blades "prop fan".

  Another remarkable property of fiber reinforced materials is that it is possible to act on the properties of the building element by arranging the fibers in preferential directions. It is thus possible to obtain different characteristics of the material in different directions, for example as regards the modulus of elasticity or the damping constants. However, the manufacture of complicated structural elements made of fiber-reinforced material poses technical problems, in particular if the surfaces are left-handed in space, especially with partially concave shapes, and if different strength and vibration properties in different directions. This applies in particular to fan blades or "prop fan" propeller blades of new turboprop engines for which the arrangement of the blades on the blade root or on the rotor poses a problem.

another particular problem.

  The current manufacture of such building elements involves a high expense, resulting in. high manufacturing costs accordingly. Thus, elements called "prepregs", that is to say fiber plates impregnated with a coating material, are placed in a hollow mold, and these plates are then hardened by the action of pressure and pressure. temperature. It is therefore disadvantageous that, with this manufacturing process, it is impossible to affect the properties of the building elements, which is known to be possible, only by incurring an expense.

very high.

  It is an object of the invention to provide a method for producing left-handed rotor blades in space, which method allows simple and fast fabrication, the properties of the building elements being able to be modified in a desired way by an intentional arrangement of the fibers. We must then be able to obtain a good arrangement of the fibers,

  especially in the case of surfaces of concave shapes.

  To this end, the invention relates to a process of the above type, characterized in that fiber cords impregnated with resin coating are pressed against the core by means of a pressure roller and the resin is cured. coating immediately after pressing in a precure plant

  3G coupled with the pressure roller.

  Advantageous embodiments of

  the invention are indicated below.

  The method according to the invention provides an advantage in that the fibers can be arranged simply in each direction on surfaces of any shape of the rotor blade and attached thereto.

  by adhesion, that is to say, they do not slip anymore.

  After the fibers have hardened, they also adhere to concave surfaces, which ensures fast and precise fiber placement. It is possible, depending on the requirements, to have several layers of fibers superimposed with the same orientation or different orientations. The pre-hardening plant gels the coating material so that the fibers are stuck in their position, the mixture of fibers and

  however, the coating material has not yet hardened.

  Then, the coiled construction element is compressed into a mold at the final dimension, then it is hardened into

an oven.

  In addition, the time required to manufacture a construction element according to the wound fiber technique is considerably shortened compared to conventional methods. It is furthermore essential that the concave-shaped blades can be covered in a simple and precise manner with layers of fibers which is only insufficiently possible with the conventional layout methods. This advantageously results in a significant simplification of the winding process, which is suitable for an entirely

  automatic with control by computers and robots.

  The fiber cords may advantageously be arranged along preferential lines. It is thus possible to obtain, intentionally, an anisotropic structure of the building element, so that arrangements can be made which promote stability and resistance. It is thus possible, in particular, to delete

vibration problems.

  According to an advantageous embodiment of the invention, the fiber cords for fixing the rotor blade to a blade root can be looped around a series of fastening buttons disposed on the blade root. It is thus possible to obtain a particularly favorable introduction in the blade root of the centrifugal forces acting in service.

  The invention is described in more detail below.

  after referring to the accompanying drawings, in which: - Figure 1 is a perspective view of a fan blade, - Figure 2 is a perspective view of the fiber arrangement apparatus, - Figure 3 is a perspective view of a

six-axis gantry robot.

  FIG. 1 represents a rotor blade 1 that can be manufactured using the method according to the invention. The preferred directions of the fibers to be arranged have been indicated: the direction of

  main traction 2 and oblique layers 3 and 4.

  Preferably, the fibers are guided around retaining buttons 5 arranged on a blade root 6. This provides a good connection between the two construction elements and the tensile forces that develop during the operation of the blade are well.

  introduced into the foot 6 of this blade.

  FIG. 2 represents a device 8 for disposing the fibers consisting essentially of a roll of fibers 10 of a conduit 12 for feeding fibers, a pressure roller for fibers 11. and a precuring installation 15. The fiber bead 9 unwound from the fiber reserve roll 10 is pulled by the fiber pressure roller 11 through the fiber feed conduit 12. At the same time, coating material is fed to the fiber bead in defined amounts from the coating material metering device 14 and passing through the coating material feeding conduit 13. The coating material is fed to the coating material metering device 14 from the storage tank 16 and through a flexible supply line 17. The volume of coating material can then be adjusted. fed for a given length of the fibers, this volume being preferably adapted to the flow rate of the fibers. The fibers thus impregnated are laid exactly along the predetermined course on the core of the building element 1 by the pressure roller of the fibers 11 and they are hardened (gelled) by means of the precuring installation 15, so that the surface becomes dry. In this way, the fibers are fixed to such an extent that they can be arranged along curved lines. Other precured fibers can then be

  layers of fibers in any direction.

  As can be seen in FIG. 3, the fiber arrangement device 8, shown schematically, is mounted on the "wrist" of a six-axis portal robot 7 and can thus, by being controlled by a computer, have the fiber cord 9 fully automatically on the core of the construction element according to the plots calculated in advance. We can thus have a possibility of reproduction very

  precise (<0.2mm) of the arrangement of the fibers.

  After the blank thus manufactured has been fully wound, it is then placed in a mold and cured in a conventional manner by means of

pressure and temperature.

  It is advantageous for the precuring installation to be in the form of a radiator

with infrared rays.

262478 6

Claims (4)

  1 - Process for producing a left-handed rotor blade (1) in space by surrounding a core with a fiber material impregnated with resin, characterized in that it is pressed by means of a pressure roller (11) fiber bundles (9) impregnated with a coating resin against the core and the coating resin is cured immediately after pressing in a precuring device (15) coupled with the pressure roller (11).   2 - Process according to claim 1, characterized in that, for fixing the blade on a blade root (6), the fiber bundles are looped on a series of fastening buttons (5) arranged on the foot of blade (6).   3 - Process according to claim 1, characterized in that the precuring installation is constituted in the form of radiator spokes infrared.   4 - Process according to any one of   Claims 1 to 3, characterized in that   means of the pressure roller (11) the fiber cords through a fiber feed duct by adding   then from the coating material to the fiber cords.