Abstract: A hollow body molding device having molten resin injected into a main cavity, fluid is pressure-injected through a pressure port after the injection of molten resin, a floating core moves to the outlet side, the molten resin is extruded from the outlet simultaneously with the movement of the floating core, and a hollow molded body is molded, the hollow body molding device having a floating core storage portion connected to the main cavity and stores the floating core moved by the pressurized fluid, an auxiliary cavity stores molten resin discharged from the main cavity and the floating core storage portion, communication passages and which communicate the floating core storage portion and the auxiliary cavity with each other; and an opening and closing means that opens and closes the communication passages by sliding movement. In the hollow body molding device, each inlet cross-sectional area B of the communication passages is specified.

Abstract: The present invention includes injecting a molten resin into a main cavity, which has on its one end a pressure port provided with a floating core and on its other end a first outlet, and a branch cavity, which communicates with the main cavity and has on its end a second outlet allowed to open and close, injecting a pressurized fluid through the pressure port after the injection of the molten resin, and moving the floating core to the first outlet side, and, at the same time, extruding the molten resin from the first outlet to form a main pipe hollow, and opening the second outlet after the main pipe hollow reaches a portion at which the branch cavity communicates with the main cavity, and extruding the molten resin by the pressurized fluid from the second outlet to form the branch pipe hollow.

Abstract: A hollow body formed of a thermoplastic resin and having uniform inner diameter and thickness and an excellent inner surface smoothness, and, in particular, a pipe-shaped hollow body having a bent portion is manufactured by injection molding. A method of manufacturing a hollow body includes injecting a molten resin 8 into a mold cavity 2 of a mold 1, the mold cavity 2 having on its one end a pressure port 4 provided with a floating core 6 and on its other end an outlet 5, pressure-injecting a pressurized fluid through the pressure port 4 after the injection of the molten resin 8, and moving the floating core 6 toward the outlet 5, and, at the same time, extruding the molten resin 8 from the outlet 5.

Abstract: In a resin heat exchanger unit, a resin pipe having straight portions and curved portions and a plurality of resin fins are integrally molded and there can be realized high reliability, high heat exchange efficiency, and a simple manufacturing process. The resin heat exchanger unit includes a resin pipe (1), which has straight portions (2) and curved portions (3) provided alternatively and continuously, and a plurality of resin fins (4) connected to the pipe (1), the pipe (1) and the fins (4) being integrally injection-molded.

Abstract: The present invention provides a hollow body molding device which allows easy confirmation of passage of a floating core through a molded body and facilitates quality control at the site.

Abstract: A hollow body formed of a thermoplastic resin and having uniform inner diameter and thickness and an excellent inner surface smoothness, and, in particular, a pipe-shaped hollow body having a bent portion is manufactured by injection molding. A method of manufacturing a hollow body includes injecting a molten resin 8 into a mold cavity 2 of a mold 1, the mold cavity 2 having on its one end a pressure port 4 provided with a floating core 6 and on its other end an outlet 5, pressure-injecting a pressurized fluid through the pressure port 4 after the injection of the molten resin 8, and moving the floating core 6 toward the outlet 5, and, at the same time, extruding the molten resin 8 from the outlet 5.

Abstract: The present invention provides a method of manufacturing a pipe with a branch, which utilizes the conventional pipe molding method using a floating core, and while taking advantage of the pipe molding method, various types of pipes with a branch can be integrally molded with a synthetic resin with high efficiency.

Abstract: A resin molded body can give a heat-insulating or radiation function of providing extremely good heat transfer, has high reliability, and is manufactured with a simple process at low cost. The resin molded body is formed by integrally injection molding of a pipe portion (1), which has at least a curved portion (3) and passes a fluid therethrough, and a flat plate portion (4).

Abstract: In a resin heat exchanger unit, a resin pipe having straight portions and curved portions and a plurality of resin fins are integrally molded and there can be realized high reliability, high heat exchange efficiency, and a simple manufacturing process. The resin heat exchanger unit includes a resin pipe (1), which has straight portions (2) and curved portions (3) provided alternatively and continuously, and a plurality of resin fins (4) connected to the pipe (1), the pipe (1) and the fins (4) being integrally injection-molded.