Thickness direction thread insertion needle, and method for producing three-dimensional fibrous structure

Abstract

Thickness direction thread insertion needles ( 11 ) each include a proximal end portion ( 12 ) and an insertion portion ( 13 ), which is formed thinner than the proximal end portion ( 12 ) and is selectively inserted in laminated fiber layers ( 23 ). The insertion portion ( 13 ) includes a distal end and a needle's eye formed close to the distal end. A coating ( 15 ) is formed on the insertion portion ( 13 ). The coating ( 16 ) has a surface roughness of 0.1 μm or more and 0.7 μm or less in terms of the center line average roughness Ra, and improves the wear resistance of the insertion portion ( 13 ). The thickness direction thread insertion needles ( 11 ) are used in producing a three-dimensional fibrous structure. The three dimensional fibrous structure includes the laminated fiber layers ( 23 ) formed by laminating fiber layers to be at least biaxially oriented, and thickness direction threads (P) inserted in a direction to intersect the fiber layers to connect the laminated fiber layers ( 23 )

1 . A thickness direction thread insertion needle used for producing a three-dimensional fibrous structure, the three-dimensional fibrous structure including laminated fiber layers formed by laminating a plurality of fiber layers to be at least biaxially oriented, and a thickness direction thread inserted in a direction to intersect the fiber layers to connect the laminated fiber layers, the thickness direction thread insertion needle comprising:
 a proximal end portion;   an insertion portion, which is formed to be thinner than the proximal end portion and is selectively inserted in the laminated fiber layers, the insertion portion including a distal end and a needle's eye formed close to the distal end; and   a coating formed on the insertion portion, the coating having a surface roughness of 0.1 μm or more and 0.7 μm or less in terms of the center line average roughness Ra, and the coating improves the wear resistance of the insertion portion.   
   
   
       2 . The thickness direction thread insertion needle according to  claim 1 , wherein the laminated fiber layers and the thickness direction thread are each formed by a carbon fiber bundle. 
   
   
       3 . The thickness direction thread insertion needle according to claim  1 , wherein the coating is formed by roughening the surface of needle material of the thickness direction thread insertion needle and then coating the surface with plating. 
   
   
       4 . The thickness direction thread insertion needle according to  claim 3 , wherein treatment for roughening the surface of the needle material is performed by shot blasting. 
   
   
       5 . The thickness direction thread insertion needle according to  claim 1 , wherein the coating is formed by composite plating. 
   
   
       6 . A thickness direction thread insertion needle comprising:
 a proximal end portion; and   an insertion portion, which is formed to be thinner than the proximal end portion and is selectively inserted in laminated fiber layers, the insertion portion including a distal end and a needle's eye formed close to the distal end, the surface of the insertion portion includes a plurality of grooves extending in an axial direction of the insertion portion, and the surface of the insertion portion is coated with wear resistant plating.   
   
   
       7 . A method for producing a three-dimensional fibrous structure, the three-dimensional fibrous structure including laminated fiber layers formed by laminating a plurality of fiber layers to be at least biaxially oriented, and a thickness direction thread inserted in the laminated fiber layers to intersect the fiber layers thereby connecting the laminated fiber layers, the laminated fiber layers including an insertion area in which the thickness direction thread is inserted, the production method comprising:
 arranging a plurality of thickness direction thread insertion needles in a row, each thickness direction thread insertion needle including a proximal end portion, an insertion portion, which is formed to be thinner than the proximal end portion and is selectively inserted in the laminated fiber layers, the insertion portion including a distal end and a needle's eye formed close to the distal end, and a coating formed on the insertion portion, the coating having a surface roughness of 0.1 μm or more and 0.7 μm or less in terms of the center line average roughness Ra, and the coating improves the wear resistance of the insertion portion;   simultaneously thrusting a plurality of thickness direction thread insertion needles arranged in a row into the laminated fiber layers with the thickness direction threads in a state where the laminated fiber layers are retained on a frame, so as to cause the needle's eyes of the thickness direction thread insertion needles to project outside of the laminated fiber layers, such that loops are formed by the thickness direction threads on the side of the laminated fiber layers from which the thickness direction thread insertion needles project;   inserting a lock yarn in the loops along an arrangement direction of the thickness direction thread insertion needles;   tightening the laminated fiber layers by pulling back the thickness direction thread insertion needles from the laminated fiber layers after inserting the lock yarn in the loops; and   inserting the thickness direction yarn in the insertion area of the laminated fiber layers by repeating the forming of loops, the insertion of the lock yarn, and the tightening of the laminated fiber layers, and then removing the laminated fiber layers from the frame.   
   
   
       8 . A method for producing a three-dimensional fibrous structure, the three-dimensional fibrous structure including laminated fiber layers formed by laminating a plurality of fiber layers to be at least biaxially oriented, and a thickness direction thread inserted in the laminated fiber layers to intersect the fiber layers thereby connecting the laminated fiber layers, the laminated fiber layers including an insertion area in which the thickness direction thread is inserted, the production method comprising:
 arranging a plurality of thickness direction thread insertion needles in a row, each thickness direction thread insertion needle including a proximal end portion and an insertion portion, which is formed to be thinner than the proximal end portion and is selectively inserted in the laminated fiber layers, the insertion portion including a distal end and a needle's eye formed close to the distal end, the surface of the insertion portion includes a plurality of grooves extending in an axial direction of the insertion portion, and the surface of the insertion portion is coated with wear resistant plating;   simultaneously thrusting a plurality of thickness direction thread insertion needles arranged in a row into the laminated fiber layers with the thickness direction threads in a state where the laminated fiber layers are retained on a frame, so as to cause the needle's eyes of the thickness direction thread insertion needles to project outside of the laminated fiber layers, such that loops are formed by the thickness direction threads on the side of the laminated fiber layers from which the thickness direction thread insertion needles project;   inserting a lock yarn in the loops along the arrangement direction of the thickness direction thread insertion needles;   tightening the laminated fiber layers by pulling back the thickness direction thread insertion needles from the laminated fiber layers after inserting the lock yarn in the loops; and   inserting the thickness direction yarn in the insertion area of the laminated fiber layers by repeating the forming of loops, the insertion of the lock yarn, and the tightening of the laminated fiber layers, and then removing the laminated fiber layers from the frame.