초록 ▼

The object of the invention is a process for forming sectors of the air intake lip of an aircraft nacelle, of U-shaped cross-section, characterized in that it comprises producing, from a cylindrical billet (11) of a suitable material, by hot die pressing, a tubular profile (12) of U-shaped cross-sec

The object of the invention is a process for forming sectors of the air intake lip of an aircraft nacelle, of U-shaped cross-section, characterized in that it comprises producing, from a cylindrical billet (11) of a suitable material, by hot die pressing, a tubular profile (12) of U-shaped cross-section whose ends are interconnected, a portion of the section formed by the U having a development less by several percent than the development of the smallest cross-section of the lip sector to be obtained, in giving to the profile (12) at the outlet of the die (15) a curvature whose radius is substantially equal to the mean radius of said sector, then in forming and calibrating the profile (12) to the final shapes of the sector by hydraulic expansion in a matrix whose interior corresponds to the external volume of said sector increased by the resilient return of the material to be expanded, and finally, cutting off the tubular product thus formed to separate the portion of U-shaped cross-section constituting said lip sector.

대표청구항 ▼

1. Process for forming sectors of an air intake lip of an aircraft nacelle, of U-shaped transverse cross-section, characterized in that it consistsin producing, from a cylindrical billet (11) of a suitable material, by hot die pressing, a tubular profile (12) of U-shaped transverse cross-section who

1. Process for forming sectors of an air intake lip of an aircraft nacelle, of U-shaped transverse cross-section, characterized in that it consistsin producing, from a cylindrical billet (11) of a suitable material, by hot die pressing, a tubular profile (12) of U-shaped transverse cross-section whose ends are interconnected, a portion of U-shaped section (S1) having a development less by several percent than the development of the smallest cross-section of the sector of lip to be obtained, giving to the profile (12) at the outlet of the die (15) a curvature whose radius is substantially equal to the mean radius of curvature of said sector, then forming and calibrating the profile (12) to the final shapes of the sector by hydraulic expansion in a matrix (M1, M2) whose interior corresponds to the external volume of said sector increased by the resilient return of the material to be expanded, and finally, cutting off the tubular product thus obtained to separate the U-shaped transverse cross-section portion constituting said lip sector. 2. Process according to claim 1, characterized in that the curvature of the tubular profile (12) at the outlet of the die (15) is achieved by downstream control of the passage of the material from the die, the preservation of the curvature after leaving the die being effected by a suitable guide device.3. Air inlet lip sector obtained according to the process of claim 2.4. Device for practicing the process according to claim 1, characterized in that it comprises:an extrusion die device (13 to 15), means (16; 17 to 20) arranged at the outlet of the die (15) to give to the die-formed product (12) a suitable curvature, and a matrix for calibrated forming of said die-formed product (12). 5. Device according to claim 4, characterized in that said means for curving the die-formed product (12) are constituted by a fixed bent guide trough (16).6. Device according to claim 5, characterized in that the matrix is in two parts (M1, M2), one part (M1) comprising a recess (21) corresponding to the U-shaped cross-section portion (S1) of the tubular die-formed product (12) and the other portion (M2) comprising a recess (22) corresponding to the remaining cross-sectional portion (S2) of said product (12).7. Device according to claim 4, characterized in that said means for curving the die-formed product (12) are constituted by a rotatable plate (17) carrying a bent guide trough (19) whose shape matches the flank of the die-formed product (12) and which is provided at one end with a gripper (20) for gripping the front end of said die-formed product.8. Device according to claim 7, characterized in that the matrix is in two parts (M1, M2), one part (M1) comprising a recess (21) corresponding to the U-shaped cross-section portion (S1) of the tubular die-formed product (12) and the other portion (M2) comprising a recess (22) corresponding to the remaining cross-sectional portion (S2) of said product (12).9. Device according to claim 4, characterized in that the matrix is in two parts (M1, M2), one part (M1) comprising a recess (21) corresponding to the U-shaped cross-section portion (S1) of the tubular die-formed product (12) and the other portion (M2) comprising a recess (22) corresponding to the remaining cross-sectional portion (52) of said product (12).10. Device according to claim 9, characterized in that the two portions of the assembled matrix (M1, M2) are closed at the ends by a plug plate (24) for gripping the ends of the die-formed product (12) to be expanded, one of the plates being provided with a conduit (30) for introduction of a hydraulic fluid under pressure within said product (12).11. Air inlet lip sector obtained according to the process of claim 1.