3. CFRP Propeller Shaft from MFW + RTM Manufacturing Process
Hitachi has developed a new structure and manufacturing process for carbon fiber reinforced plastics (CFRP) propeller shafts and achieved a significant weight reduction and cost savings.
The conventional filament winding (FW) manufacturing process wound fiber tow, which leads to a loss in strength due to crossing (crimping) of the fibers due to the back-and-forth motion of FW, requiring considerable manufacturing time.
The new manufacturing process, multi-thread filament winding (MFW), enables carbon fibers to be layered without crossing each other, and the layering (non-crimping) is used to maximize the performance of the carbon fibers. Also, by setting the optimum amount of two types of fibers [polyacrylonitrile (PAN) and pitch-based fibers] that each emphasize tensile strength and elastic properties, the amount of material used was reduced and a significant weight reduction was achieved. In addition, the multi-thread feeding greatly reduced the cycle time compared to the conventional FW and saved the cost.
Also, the resin transfer molding (RTM) manufacturing process and an immediate curing resin has reduced the cycle time to only a few minutes from the several hours required for conventional curing in a curing furnace. The resulting high cycle rate made it possible to cut manufacturing costs. Furthermore, this manufacturing process integrally molds them during injection molding instead of the conventional high-precision serration press-fit control of the metal parts at both ends of the tube, thereby improving the reliability of the fastening parts.
(Hitachi Astemo, Ltd.)
［03］CFRP propeller shaft from MFW + RTM manufacturing process