JP2021146560A - Molding system for hollow molded article - Google Patents

Abstract

To provide a hollow molded article having excellent strength by suppressing the occurrence of voids.SOLUTION: A molding system 1 for a hollow molded article made of a fiber reinforced resin comprises: a mold 40 provided with a cavity with an outer shell shape of the hollow molded article; a bag 30 disposed in the mold 40; and a temperature-control circulation device 20 for supplying heated fluid into the bag 30. Superheated steam as the heated fluid is circulated between the temperature-control circulation device 20 and the bag 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to a molding system for a hollow molded product made of a fiber reinforced resin.

Hollow molded products made of fiber reinforced plastic are lightweight and have excellent strength, and are therefore used as structural materials for sports equipment such as golf club shafts and tennis rackets, and automobiles and aircraft. As a molding method for such a hollow molded product, a so-called internal pressure molding method is known.

Patent Document 1 describes that a cylindrical hollow molded product is molded by an internal pressure molding method. Here, a fluororubber tube as a molding bag coated with a molding base material made of fiber reinforced resin is placed in a heated mold, and nitrogen gas is injected into the fluororubber tube. As a result, the molding material is pressed against the inner surface of the mold. Before injecting nitrogen gas, the inside of the mold is depressurized to a predetermined degree of vacuum by a vacuum pump, and the vacuum state is maintained even during molding. It is said that a hollow molded product having a complicated shape can be molded by increasing the degree of vacuum in the mold.

Japanese Unexamined Patent Publication No. 5-329856

By the way, in the conventional internal pressure molding method as described in Patent Document 1, the internal pressure applied by compressed air such as nitrogen gas is at most about 0.5 MPa, and the molding base material is pressed against the inner surface of the mold. It is not enough as a pressing force. Therefore, it is difficult for the compressed air to sufficiently spread to every corner of the hollow molded product, and the pressing on the inner surface of the mold may be insufficient. Insufficient pressing on the inner surface of the mold tends to generate voids between the molded base materials, which causes voids in the molded product after molding. If a large number of voids are generated in the hollow molded product, the strength at that portion cannot be ensured, and the strength of the hollow molded product may decrease. The problem caused by insufficient pressing force is a problem that can occur even when the inside of the mold is depressurized to a predetermined degree of vacuum.

The present invention has been made to solve these conventional problems, and an object of the present invention is to suppress the generation of voids and provide a hollow molded product having excellent strength.

In order to solve the above problems, the molding system for a hollow molded product made of a fiber-reinforced resin of the present invention includes a mold having an outer shell-shaped cavity of the hollow molded product and a bag arranged in the mold. A temperature control circulation device that supplies a heated fluid into the bag is provided, and superheated steam as the heated fluid is circulated between the temperature control circulation device and the bag.

According to the above configuration, a hollow molded product made of fiber reinforced resin can be molded while supplying superheated steam into the bag, so that not only the temperature required for molding can be obtained but also compressed air is supplied. It is possible to apply a higher pressure to the inside of the bag as compared with the above. Therefore, the molding base material made of fiber reinforced resin can be pressed against the inner surface of the mold with a strong pressing force, and the generation of gaps between the layers of the molding base material is suppressed. As a result, the generation of voids in the molded product is suppressed, and a hollow molded product having excellent strength can be obtained.

In the above configuration, the temperature control circulation device includes a heating device that generates superheated steam and a temperature sensor that detects the temperature of the superheated steam, and the temperature sensor is a supply side of the superheated steam from the heating device to the bag. The temperature control circulation device is preferably provided with a temperature control means for adjusting the temperature of the superheated steam in the heating device based on the detected value of the temperature of the superheated steam by the temperature sensor. ..

According to the above configuration, superheated steam of a desired temperature and pressure can always be supplied into the bag in a state where fluctuations in molding temperature and molding pressure are suppressed. Therefore, it is possible to mold the molded base material made of reinforced resin while constantly pressing it against the inner surface of the mold with a desired pressing force, whereby a hollow molded product having excellent strength can be obtained.

In the above configuration, the temperature control circulation device further includes a pressurizing pump, and the pressurizing pump is provided on the supply side of superheated steam from the heating device to the bag and on the upstream side of the temperature sensor. It is preferable that the temperature control means adjusts at least one of the heating temperature in the heating device and the supply pressure in the pressurizing pump based on the detected value of the temperature of the superheated steam by the temperature sensor.

According to the above configuration, it is easy to control the temperature and pressure of superheated steam.
In the above configuration, it is preferable to include a cold water circulation device that circulates water as the fluid with the temperature control circulation device.

According to the above configuration, water can be circulated between the cold water circulation device and the bag via the temperature control circulation device at the start of molding. Therefore, before molding, the inside of the temperature control circulation device, the inside of the bag, or the inside of the cold water circulation device, the temperature control circulation device, and the fluid passage connecting the bags can be filled with water. As a result, the air existing inside the fluid passage or the like can be easily removed. Further, at the end of molding, the superheated steam used for molding can be discharged to the outside together with the water in the cold water circulation device. In this way, it is possible to easily supply the fluid at the start of molding and discharge the fluid at the end of molding.

In the above configuration, the bag is preferably made of silicone resin.
Silicone resin is not only excellent in heat resistance but also excellent in flexibility. Therefore, even if the inner surface shape of the mold is complicated, it is easy to follow the shape, and the pressure applied to the inside of the bag can be evenly transmitted to the molding base material. In addition, since it is also excellent in releasability, it can be easily taken out from the hollow molded body after molding.

According to the present invention, the generation of voids is suppressed, and a hollow molded product having excellent strength can be obtained.

The schematic diagram of the molding system of the hollow molded article of this embodiment. Longitudinal sectional view of the mold. Partial cross-sectional view of the mold with the mold tightened. It is a sectional view in the lateral direction of a mold, and is the sectional view taken along line AA in FIG. Perspective view of the adapter. Flowchart at the time of starting up the molding system. Flowchart at the time of molding in the molding system. Flowchart at the end of the molding system.

Hereinafter, an embodiment of a molding system for a hollow molded product embodying the present invention will be described.
As shown in FIG. 1, the molding system 1 of the present embodiment includes a cold water circulation device 10, a temperature control circulation device 20, a bag 30, and a mold 40.

In the present embodiment, a case where a long cylinder having a rectangular cross section in the radial direction is molded as a hollow molded product made of fiber reinforced resin will be described. As shown in FIGS. 3 and 4, the molded product is formed by laminating a plurality of layers of a sheet-shaped molding base material 60 made of fiber reinforced resin in the cavity of the mold 40 and heating and curing the molded product in the mold 40. NS. The material of the fiber reinforced resin material constituting the molded base material 60 is not particularly limited. Conventionally known reinforcing fibers and resins can be used. Examples of the reinforcing fiber include carbon fiber, glass fiber, aramid fiber and the like. Further, as the resin, a thermosetting resin is preferable, and examples thereof include an epoxy resin and a polyester resin.

The molding system 1 is configured to circulate water as a fluid between the devices constituting the molding system 1 while changing the state.
As shown in FIG. 1, water is stored inside the cold water circulation device 10. A supply pump 11 is built in the chilled water circulation device 10, and water is supplied from the chilled water circulation device 10 to the temperature control circulation device 20 by the supply pressure of the supply pump 11. The cold water circulation device 10 may be an air-cooled type or a water-cooled type.

The temperature control circulation device 20 includes a heating device 21, a pressure pump 22, and a temperature sensor 23. The heating device 21 heats the water supplied from the cold water circulation device 10 to 100 ° C. or higher to generate superheated steam. The pressurizing pump 22 adjusts the supply pressure when supplying the superheated steam generated by the heating device 21 to the bag 30. The pressurizing pump 22 is provided with a pressure adjusting means (not shown) for adjusting the supply pressure of superheated steam. The temperature sensor 23 detects the temperature of the superheated steam generated by the heating device 21.

The bag 30 is placed inside the mold 40 prior to molding. At the time of molding, the superheated steam generated by the heating device 21 is supplied to the inside of the bag 30 via the pressurizing pump 22, and the superheated steam is circulated with the temperature control circulation device 20. Therefore, the bag 30 is made of a synthetic resin having excellent heat resistance and flexibility and is formed in a cylindrical shape. The material of the synthetic resin is not limited at times, but it is excellent in flexibility and heat resistance in that it easily follows the cavity shape of the mold 40 during molding and can maintain the strength against the temperature of superheated steam during molding. It is preferably made of silicon resin.

As shown in FIG. 2, the mold 40 includes an upper mold 41 and a lower mold 42, and a long cavity along the outer shell shape of the hollow molded product is formed inside by molding. The upper mold 41 is formed with a recess 41a, a recess 41b, and a recess 41c, and the lower mold 42 is formed with a recess 41a, a recess 42b, and a recess 42c. The recess 41a and the recess 42a form the outer shell shape of the hollow molded product by molding, and the molding base material is arranged at the time of molding. The recess 41b and the recess 42b form the outer shell shape of the adapter 50, which will be described later, by molding, and the adapter 50 is arranged at the time of molding. At the time of molding, the recess 41c and the recess 42c are arranged with the bag 30 of the portion not covered with the molding base material and the adapter 50.

As shown in FIGS. 2 and 3, fluid passages 43, which serve as passages for circulating superheated steam with the temperature control circulation device 20, are formed at both ends of the upper die 41 in the longitudinal direction. One end side of one fluid passage 43 opens to the longitudinal end surface of the upper die 41, and the other end side opens to the inner surface of the recess 41b of the upper die 41. One of the fluid passages 43 at both ends of the mold 40 constitutes a supply passage for superheated steam from the temperature control circulation device 20, and the other constitutes a discharge passage for superheated steam from the bag 30.

As shown in FIGS. 2 and 4, an annular groove 44 is recessed on the upper surface of the lower mold 42 so as to surround the recesses 42a, 42b, and 42c. An O-ring 45 is fitted in the groove 44, and the O-ring 45 is compressionally deformed with the upper mold 41 at the time of mold clamping to ensure the airtightness in the cavity.

As shown in FIGS. 3 and 5, at the time of molding, an adapter 50 for fixing the bag 30 and communicating the fluid passage 43 with the inside of the bag 30 is arranged in the mold 40. The adapter 50 is arranged so as to face each of both ends of the mold 40 in the longitudinal direction.

As shown in FIG. 5, the adapter 50 includes an adapter main body 51, a leaf spring 52, and a tightening member 53. The adapter main body 51 is formed with a base portion 54 and a tubular portion 55. Here, for convenience of explanation, the side of the adapter body 51 where the tubular portion 55 is formed is above the adapter 50, and the side where the base portion 54 is formed is below.

The adapter body 51 is formed with a fluid passage 56 that serves as a passage for superheated steam. One end side of the fluid passage 56 is open to the side surface of the adapter main body 51, and the other end side is open to the upper surface of the adapter main body 51. As shown in FIG. 3, when the adapter 50 is arranged in the recesses 41b and 42b of the mold 40, the opening on one end side matches the position of the fluid passage 43 on the upper mold 41, and the opening on the other end side is the bag 30. Open toward. Of the adapters 50 arranged at both ends in the longitudinal direction of the mold 40, in one of the adapters 50, the fluid passage 56 of the adapter main body 51 constitutes a supply passage of superheated steam from the temperature control circulation device 20, and the other. The adapter 50 constitutes a discharge passage for superheated steam from the bag 30.

As shown in FIG. 5, the tubular portion 55 is formed in a double tubular shape including a cylindrical inner tubular portion 57 and an outer tubular portion 58 having the same center. The outer peripheral surface of the inner cylinder portion 57 is formed so as to have the same diameter in the vertical direction, while the inner peripheral surface of the inner cylinder portion 57 is formed in a tapered shape so as to increase in diameter toward the upper side. As a result, when the adapter 50 is arranged in the mold 40, the fluid passage 56 has a shape in which the diameter increases toward the bag 30 as shown in FIG. Further, the inner peripheral surface of the outer cylinder portion 58 is formed in a tapered shape whose diameter increases upward. The outer peripheral surface of the outer cylinder portion 58 is formed so as to have the same diameter in the vertical direction, and a thread into which the tightening member 53 is screwed is formed.

As shown in FIGS. 3 and 5, the leaf spring 52 is arranged in the space between the outer peripheral surface of the inner cylinder portion 57 and the outer peripheral surface of the outer cylinder portion 58. At the time of molding, the end portion of the bag 30 is arranged on the inner peripheral side of the leaf spring 52, and the bag 30 is externally fitted to the inner cylinder portion 57 together with the leaf spring 52. The outer peripheral surface of the leaf spring 52 is formed in a tapered shape whose diameter increases upward. Therefore, when the leaf spring 52 is inserted into the space between the inner cylinder portion 57 and the outer cylinder portion 58, the outer peripheral surface of the leaf spring 52 is pushed by the tapered inner peripheral surface of the outer cylinder portion 58. The end portion of the bag 30 is tightened by the leaf spring 52 and pressed against the outer peripheral surface of the inner cylinder portion 57. As a result, the airtightness inside the bag 30 is maintained.

Next, the molding method of the hollow molded product by the molding system 1 will be described together with the operation.
The molding method of the hollow molded product includes a pre-step of attaching the adapter 50 to the bag 30, a molding base-placement step of arranging the fiber-reinforced resin molding base 60 in the cavity of the mold 40, and the bag 30 in the lower mold 42. It is provided with a molding step of arranging and molding, a preparatory step of starting the molding system 1, a molding step of molding the molded body by the molding system 1, a finishing step of ending the molding system 1, and a post-step of taking out the molded body. ing.

In the previous step, a cylindrical bag 30 having a length substantially the same as the length of the cavity of the mold 40 in the longitudinal direction is prepared, and the adapter 50 is attached to each of both ends thereof. After the tightening members 53 are outer-fitted from each of both ends of the bag 30, leaf springs 52 are outer-fitted to each of both ends of the bag 30. Subsequently, at each of both ends of the bag 30, the leaf springs 52 are fitted together with both ends of the bag 30 into the space between the inner cylinder portion 57 and the outer cylinder portion 58 of the adapter main body 51. Then, the tightening member 53 previously outlined is tightened from the outer peripheral surface of the outer cylinder portion 58 of the adapter main body 51 attached to both ends. As a result, the adapters 50 are attached to both ends of the bag 30, and the internal space of the bag 30 is in a state of communicating with the outside through the fluid passage 56 formed in the adapter 50.

In the molding base material arranging step, the molding base material 60 is arranged in the recess 42a of the lower mold 42. As shown in FIG. 4, the molding base material 60 arranged in the lower mold 42 has a length substantially the same as the length in the longitudinal direction of the recess 42a in advance, and the inner peripheral surface of the cavity of the mold 40 in the lateral direction. Prepare a plurality of pieces cut into a shape slightly shorter than the length of the above and stack them in order. The orientation angle of the reinforcing fibers in the molded base material 60 may be appropriately adjusted according to the properties required for the molded product. This also applies to the molding base material 60 arranged on the upper mold 41 side during the mold clamping step described later.

In the mold clamping step, the bag 30 to which the adapter 50 is attached is arranged inside the lower mold 42. Subsequently, the molding base material 60 is placed from above the bag 30. As shown in FIG. 4, the molded base material 60 here is previously cut into a shape having substantially the same length as the length of the recess 41a in the longitudinal direction and slightly shorter than the length of the recess 41a in the lateral direction. Prepare multiple pieces and stack them in order. In this state, the upper mold 41 is placed on the lower mold 42, and the mold is fastened with a fastener (not shown). As shown in FIG. 4, in the state where the mold 40 is molded, the O-ring 45 fitted in the groove 44 of the lower mold 42 is compressed and pressed against the lower surface of the upper mold 41, and the inside of the cavity of the mold 40 is filled. It is kept airtight.

As shown in FIG. 1, in the preparatory step for starting the molding system 1, the supply pump 11 and the pressurizing pump 22 of the molding system 1 are turned on, and are provided in the fluid passage on the chilled water circulation device 10 side of the heating device 21. The discharge port 21a is opened. In the preparatory step, heating by the heating device 21 is not performed. The supply pressure of the supply pump 11 supplies the water in the chilled water circulation device 10 to the heating device 21, and the supply pressure of the pressurizing pump 22 supplies the water in the heating device 21 to the bag 30. Further, the water in the bag 30 returns to the cold water circulation device 10 via the heating device 21. As a result, the first route R1 in which the fluid circulates between the cold water circulation device 10, the temperature control circulation device 20, and the bag 30 in the mold 40 is formed. The supply pressures of the supply pump 11 and the pressurizing pump 22 when the first route R1 is selected are about the same, and are preferably 0.25 MPa or more, for example.

As shown in FIG. 6, in the preparation step, the first route R1 is selected in step S11, and water as a fluid is supplied from the cold water circulation device in step S12. By circulating the supplied water on the first route R1, the inside of the temperature control circulation device 20 or the inside of the bag 30 or the cold water circulation device 10, the temperature control circulation device 20, and the bag 30 are connected before molding. The inside of the fluid passage is filled with water. As a result, the air existing inside the fluid passage or the like is eliminated.

As shown in FIG. 7, in the molding step of molding the molded product by the molding system 1, in step S21, the supply pump 11 is turned off and the drainage provided in the fluid passage on the cold water circulation device 10 side of the heating device 21 is provided. The outlet 21a is closed. As a result, the fluid in the heating device 21 is supplied into the bag 30 by the supply pressure of the pressurizing pump 22, and the fluid circulates between the temperature control circulation device 20 and the bag 30 in the mold 40. Is formed. The molding step is performed by selecting the second route R2.

In the molding step, prior to molding, the pressurizing pump 22 on the second route R2 is turned off in step S22. In step S23, heating in the heating device 21 is started in this state, and superheated steam having a predetermined temperature and a predetermined pressure is generated from the water in the heating device 21. The temperature of the superheated steam is preferably a temperature slightly higher than the thermosetting temperature of the thermosetting resin constituting the molding base material 60 made of the fiber reinforced resin. For example, when the thermosetting resin is an epoxy resin, the temperature is 40 to 40. It is preferably about 140 ° C. The pressure of superheated steam is preferably about 1.0 to 1.8 MPa.

When the superheated steam in the heating device 21 reaches a predetermined temperature, the pressurizing pump 22 is turned on in step S24 to supply the superheated steam into the bag 30 and circulate the superheated steam via the second route R2. .. The supply pressure of the pressurizing pump 22 at this time is preferably 0.85 MPa or more. Further, the flow velocity of the superheated steam may be set so that the temperatures of the superheated steam at the inlet and the outlet of the mold 40 are about the same. In the bag 30 to which the superheated steam is supplied, the internal pressure is increased by the pressure of the superheated steam, and the molding base material 60 is pressed against the inner surface of the cavity of the mold 40. Further, the thermosetting resin constituting the molded base material 60 begins to be thermoset by the heat of superheated steam. In the molding apparatus of this embodiment, the mold 40 is not heated.

As shown in FIG. 7, the molding system 1 has an adjusting means for adjusting the temperature of the superheated steam in the heating device 21 based on the detected value of the temperature of the superheated steam supplied from the heating device 21 to the bag 30. There is. The adjusting means detects the temperature of the superheated steam with the temperature sensor 23 at regular intervals, and adjusts the temperature of the superheated steam in the heating device 21 based on the detected value of the temperature.

In step S25, the temperature sensor 23 detects the temperature of the superheated steam. In step S26, the detected value of the temperature of the superheated steam is compared with the target value of the temperature of the superheated steam. Then, when it is determined that the detected value is separated from the target value by a predetermined value or more, it is determined in step S27 whether or not the detected value is lower than the target value. When it is determined that the detected value is lower than the target value, that is, when it is determined that the detected value is lower than the target value by a predetermined value or more, the heating in the heating device 21 is continued as it is in step S28. On the other hand, when it is determined that the value is higher than the target value by a predetermined value or more, the first route R1 is temporarily selected in step S29, and the superheated steam is supplied by supplying water from the cold water circulation device 10 to the temperature control circulation device 20. Adjust the temperature.

Further, even when it is determined in step S26 that the detected value is not separated from the target value by a predetermined value or more and is within the allowable range, that state is continued. Then, in step S30, it is determined whether or not a predetermined time has elapsed after the superheated steam reached a predetermined temperature and started molding via the second route R2. If it is determined that the predetermined time has not elapsed, the process returns to step S25, the detection of the temperature of the superheated steam is continued at predetermined time intervals, and if it is determined that the predetermined time has elapsed, the molding process is terminated. .. The predetermined time in step S30 may be appropriately set according to the curing temperature of the thermosetting resin constituting the molding base material 60.

Through the molding step, the thermosetting resin constituting the molding base material 60 is thermosetting in the mold 40 to form a hollow molded body. Since the temperature required for the thermosetting resin to be thermally cured is obtained by the superheated steam in the bag 30, the molded body is molded only by the heat of the superheated steam. Further, the molding base material 60 is pressed against the inner surface of the cavity of the mold 40 by the high pressure due to the superheated steam. The high internal pressure of the bag 30 suppresses the formation of gaps between the plurality of layers of the molded base material 60, and suppresses the generation of voids in the molded hollow molded body.

As shown in FIG. 8, in the final step of terminating the molding system 1, the first route R1 in the molding system 1 is selected in step S31. Specifically, the supply pump 11 and the pressurizing pump 22 are turned on, and the discharge port 21a provided in the fluid passage on the chilled water circulation device 10 side of the heating device 21 is opened. The superheated steam existing in the heating device 21, the bag 30, and the fluid passage of the second route R2 is discharged from the discharge port 21a of the heating device 21 and carried to the cold water circulation device 10. The superheated steam gradually exhausts heat in the fluid passage to the chilled water circulation device 10 to lower the temperature, and in the chilled water circulation device 10, it is appropriately mixed with the water in the chilled water circulation device 10 and discharged to the outside.

In the post-process, the mold 40 is opened, and the molded product is taken out from the inside of the mold 40 together with the bag 30 to which the adapter 50 is attached. Loosen the tightening member 53, and remove the adapter body 51 and the tightening member 53 from both ends of the bag 30. As a result, a molded body is formed around the bag 30, and leaf springs 52 are attached to both ends of the bag 30. If necessary, the molded product is obtained by removing the bag 30 from the inside of the molded product or cutting off the bag 30 at both end edges of the molded product.

Next, the effects of the molding system 1 of the above-described embodiment and the molding method of the hollow molded body will be described.
(1) The molding system 1 of the above embodiment includes a mold 40 having an outer shell-shaped cavity of a hollow molded product, a bag 30 arranged in the mold 40, and a temperature for supplying superheated steam into the bag 30. The circulation device 20 is provided. Then, superheated steam is circulated between the temperature control circulation device 20 and the bag 30.

Therefore, not only the temperature required for molding the hollow molded product can be obtained, but also a high pressure based on superheated steam can be applied to the inside of the bag 30. The molding base material 60 can be pressed against the inner surface of the mold 40 with a stronger pressing force as compared with the case where compressed air is supplied as a fluid. As a result, the generation of gaps between the layers of the plurality of molded base materials 60 is suppressed, and the generation of voids in the hollow molded product is suppressed. A hollow molded product having excellent strength can be obtained.

(2) The temperature control circulation device includes a heating device 21 that generates superheated steam and a temperature sensor 23 that detects the temperature of superheated steam, and the temperature sensor 23 detects the temperature of superheated steam at predetermined time intervals and detects the temperature. The temperature of the superheated steam in the heating device 21 is adjusted based on the value.

Therefore, superheated steam of a desired temperature and pressure can always be supplied into the bag 30 in a state where fluctuations in the molding temperature and the molding pressure are suppressed.
(3) The molding system 1 of the above embodiment includes a cold water circulation device 10 that circulates a fluid with and from the temperature control circulation device 20.

Therefore, at the start of molding, water can be circulated between the cold water circulation device 10 and the bag 30 via the temperature control circulation device 20, so that the inside of each device and the inside of the fluid passage are filled with water before molding. Can be filled. Further, at the end of molding, the superheated steam generated in the molding step can be discharged to the outside together with the water in the cold water circulation device 10. In this way, it is possible to easily supply the fluid at the start of molding and discharge the fluid at the end of molding.

(4) The temperature control circulation device 20 is a first route in which heating by the heating device 21 is continued or water is supplied from the cold water circulation device 10 based on the detected value of the temperature of the superheated steam by the temperature sensor 23. It is determined whether to select R1.

When the temperature of the superheated steam is high, water can be supplied from the chilled water circulation device 10, so that the temperature and pressure of the superheated steam can be easily controlled.
(5) The bag 30 is made of silicon resin.

Therefore, it is excellent in flexibility, and even if the inner surface shape of the mold 40 is complicated, it can easily follow the shape. The pressure applied in the bag 30 can be evenly transmitted to the molding base material 60. As a result, it is possible to suppress the generation of voids in the hollow molded product.

Further, for example, in the case of molding a curved tube as a hollow molded body, if the bag 30 is formed according to the length of the peripheral wall on the short side, the bag 30 easily extends along the peripheral wall on the long side during molding. Therefore, it is possible to suppress the slack of the bag 30 on the peripheral wall on the short side. As a result, it is possible to prevent variations in the wall thickness of the molded product.

Further, since the silicone resin is excellent in heat resistance and mold releasability, the strength is maintained at the time of molding, and it is easy to take out from the hollow molded body after molding.
(6) An O-ring 45 is fitted in the groove 44 of the lower mold 42, and the O-ring 45 is compressionally deformed with the upper mold 41 at the time of mold clamping.

Therefore, even if a situation occurs in which the fluid leaks from the bag 30 during molding, the fluid is suppressed from being discharged to the outside of the mold 40.
(7) Both ends of the bag 30 are tightened by a leaf spring 52 and a tightening member 53 provided on the adapter 50.

Therefore, even if high-pressure superheated steam is supplied into the bag 30, it is possible to realize a state in which leakage of superheated steam from the bag 30 is suppressed. Further, since the adapter 50 is provided with the leaf spring 52, it can withstand a high pressure, so that it is possible to suppress the generation of voids in the hollow molded product.

The above embodiment can be modified and implemented as follows. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

-The molding base material arranging step and the molding step are not limited to those of the above embodiment. For example, the molding base material is wound around the peripheral surface of the bag 30 to which the adapter 50 is attached, the bag 30 around which the molding base material is wound is arranged inside the lower mold 42, and the mold is fastened with the upper mold 41. May be good.

In the molding step, the temperature of the superheated steam supplied to the bag 30 was detected at predetermined time intervals, the target values of the temperature of the superheated steam were compared, and the heating temperature in the heating device 21 was adjusted. The adjusting means for adjusting the temperature of the superheated steam is not limited to this, and may be performed by adjusting the supply pressure of the pressurizing pump 22. Further, the supply pressure of the pressurizing pump 22 is adjusted together with the adjustment of the heating temperature in the heating device 21, and the temperature of the superheated steam is finely adjusted by adjusting the supply pressure in the pressurizing pump 22. May be good. In this case, when it is determined that the detected value of the temperature of the superheated steam is higher than the target value by a predetermined value or more, the pressurizing pump 22 is adjusted to loosen and it is determined that the detected value of the temperature of the superheated steam is lower than the target value by a predetermined value or more. At that time, the heating temperature of the heating device 21 may be raised.

-In the above embodiment, if it is determined in step S27 that the heating temperature of the heating device 21 is lower than the target, the heating is continued as it is, and if it is determined to be higher, the first step is temporarily performed. Route R1 was selected to supply water. The adjusting means is not limited to this, and for example, when it is determined in step S27 that the temperature is lower than the target, the set heating temperature is raised, and when it is determined to be higher, the set heating temperature is lowered. May be good.

-When the amount of superheated steam becomes insufficient in the molding step, the first route R1 may be temporarily selected to supply water from the cold water circulation device 10 to the temperature control circulation device 20.
-In the molding process, the mold 40 may be heated.

The shape of the mold 40 can be appropriately changed based on the shape of the hollow molded body.
Next, the technical idea that can be grasped from the above-described embodiment and modification is described below.
(A) A molding system for a hollow molded product made of fiber reinforced resin, which is provided with a cavity having an outer shell shape of the hollow molded product, and has an upper mold and a lower mold, and is arranged in the mold. A temperature control circulation device for circulating superheated steam between the bag and the bag is provided, and a groove is formed in at least one of the upper mold and the lower mold so as to surround the cavity, and an O-ring is formed in the groove. A molding system for hollow molded products, characterized in that a ring is arranged.

(B) An adapter having a double-tube structure having an inner cylinder portion and an outer cylinder portion and having a fluid passage for supplying superheated steam into the bag is provided in the inner cylinder portion, and the adapter includes the adapter. The bag is provided with a leaf spring that urges the outer peripheral surface of the inner cylinder portion of the bag inserted and attached to the space between the inner cylinder portion and the outer cylinder portion. B) The molding system for hollow molded products according to).

(C) A molding base material arranging step of arranging a molding base material made of fiber-reinforced resin in a cavity of a mold, a mold clamping step of arranging a bag inside the mold and molding the mold, and overheating the bag. A method for molding a hollow molded product, which comprises a molding step of supplying steam and heating the molded base material while pressing the molded base material against the inner surface of the mold by the heat and pressure from the bag.

(D) The present invention comprises a superheated steam generation step of heating water in a heating device to generate superheated steam, and the molding step is characterized in that superheated steam is circulated between the heating device and the bag. The method for molding a hollow molded product according to (c).

An example in which a hollow molded product is molded by the molding system 1 of the present invention will be described.
<Molding of hollow molded products>
A prototype 1 of a hollow molded product was molded according to the above molding method. Prototype 1 is a long cylinder having a rectangular cross section in the radial direction. As the molded base material 60, a sheet prepreg (P3252S-10, manufactured by Toray Industries, Inc.), which is a sheet-like base material in which carbon fibers are impregnated with an epoxy resin, was used. Eight layers of sheet prepregs were laminated and placed in the mold 40. In the heating device 21 of the molding system 1, the water supplied from the cold water circulation device 10 was heated to 120 ° C. After confirming that the temperature reached 120 ° C., the second route R2 of the molding system 1 was selected to supply superheated steam into the bag 30. When the temperature of the superheated steam at the inlet of the superheated steam supply passage and the temperature of the superheated steam at the outlet of the superheated steam discharge passage of the fluid passage 43 of the mold 40 were measured, they were both about 140 ° C. As a result, it was confirmed that the temperature of the superheated steam in the bag 30 was about 140 ° C. Further, the internal pressure in the bag 30 in which the superheated steam circulates was maintained at 1 to 1.5 MPa. The temperature of the superheated steam in the heating device 21 became 140 ° C., and the molding process was completed 90 minutes after the molding via the second route R2 was started. Then, prototype 1 was obtained through post-processes such as after-cure.

Further, the prototype 2 was obtained by performing the molding process in a state where the mold 40 was heated. The heating temperature of the mold 40 was set to 140 ° C. Molding was performed in the same manner as in Prototype 1 except that the mold 40 was heated.

In the molding method of prototype 1, the molding process was performed by circulating air instead of superheated steam as the heating fluid, and this was designated as prototype 3. The temperature of the air in the bag 30 was about 140 ° C., and the internal pressure in the bag 30 was about 0.5 MPa.

<Void analysis method>
The voids in prototypes 1 to 3 were analyzed to calculate the void ratio (%). A microfocus X-ray generator, TOSCANER-3 2300 μFD (manufactured by Toshiba IT Control System Co., Ltd.) was used for the void analysis. The cross-sectional image obtained by the X-ray CT scan was analyzed, and the void ratio (%) in the prototypes 1 to 3 was calculated. The void ratio (%) was ^{calculated by measuring the volume (cm 3} ) and the void volume (cm ³ ) of the hollow molded product according to the following formula. The results are shown in Table 1.

Void rate (%) = (Void volume / Volume of hollow molded product) x 100 ... (1)

表１のボイド率（％）の結果より、加熱流体として空気を循環させて成形した試作品３に対して、空気に代えて高い内圧が得られる過熱水蒸気を循環させて成形した試作品２では、ボイド率（％）の顕著な減少が見られた。試作品３では筒状の周壁全体に亘って多数のボイドが確認されたが、試作品２では、周壁全体に亘るボイドは確認されなかった。

From the results of the void ratio (%) in Table 1, the prototype 3 formed by circulating air as a heating fluid was compared with the prototype 2 formed by circulating superheated steam that can obtain a high internal pressure instead of air. , A significant decrease in void rate (%) was seen. In Prototype 3, a large number of voids were confirmed over the entire cylindrical peripheral wall, but in Prototype 2, no voids were confirmed over the entire peripheral wall.

Even in the prototype 1 formed by only the heat and internal pressure of the superheated steam in the bag 30 without heating the mold 40, the void ratio (%) was significantly reduced as compared with the prototype 3. Even in Prototype 1, no void was confirmed over the entire peripheral wall. In Prototype 1, the molding time was slightly longer than that in Prototype 2 because the mold 40 was not heated, but no significant difference was observed between Prototype 2 and Prototype 2 in terms of the generation of voids. It was found that a molded product having excellent strength can be molded only by circulating superheated steam in the bag 30.

1 ... Molding system, 10 ... Cold water circulation device, 11 ... Supply pump, 20 ... Temperature control circulation device, 21 ... Heating device, 22 ... Pressurization pump, 23 ... Temperature sensor, 30 ... Bag, 40 ... Mold, 41 ... Upper mold (mold), 42 ... lower mold (mold), 50 ... adapter, 60 ... molding material.

Claims (5)

A molding system for hollow molded products made of fiber reinforced plastic.
A mold having an outer shell-shaped cavity of the hollow molded product and
The bag placed in the mold and
A temperature control circulation device that supplies a heated fluid into the bag is provided.
A molding system for a hollow molded product, characterized in that superheated steam as the heated fluid is circulated between the temperature control circulation device and the bag. The temperature control circulation device includes a heating device that generates superheated steam and a temperature sensor that detects the temperature of the superheated steam.
The temperature sensor is provided on the supply side of superheated steam from the heating device to the bag.
The temperature control circulation device is characterized by having a temperature control means for adjusting the temperature of the superheated steam in the heating device based on the detected value of the temperature of the superheated steam by the temperature sensor. The molding system for hollow molded products according to 1. The temperature control circulation device further includes a pressure pump.
The pressurizing pump is provided on the side of supplying superheated steam from the heating device to the bag and on the upstream side of the temperature sensor.
The temperature control means is characterized in that at least one of the heating temperature in the heating device and the supply pressure in the pressurizing pump is adjusted based on the detected value of the temperature of the superheated steam by the temperature sensor. The molding system for hollow molded products according to claim 2. The molding system for a hollow molded product according to any one of claims 1 to 3, further comprising a cold water circulation device for circulating water as a fluid with the temperature control circulation device. The hollow molded product molding system according to any one of claims 1 to 4, wherein the bag is made of silicon resin.

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