JPH0647822A - Manufacture of frp-made pressure vessel - Google Patents

Abstract

PURPOSE:To reduce the generation of stress of a peripheral winding layer formed on a cross winding layer. CONSTITUTION:A cross winding layer 32 is formed on the outer peripheral face of a mandrel 13, and then a peripheral winding layer 33 is formed on the outer peripheral face of a cylindrical section 32a of the cross winding layer 32 in the state of applying tension along the axial center direction of the mandrel 13 to the cross winding layer 32. After that, the tension applied to the oblique winding layer 32 is released according to the curing shrinkage amount of the peripheral winding layer 33 so that the shrinkage deformation of the peripheral winding layer 33 is not restrained during the cool curing process of the peripheral winding layer 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pressure vessel made of FRP using the filament Waindex method (FW method).

[0002]

2. Description of the Related Art Some pressure vessels made of fiber reinforced plastic (hereinafter referred to as FRP) are manufactured by using a filament winding method (hereinafter referred to as FW method). Conventionally, a method as shown in FIG. 9 has been used for manufacturing an FRP pressure vessel using the FW method.

That is, a mandrel 3 having a cylindrical portion 1 corresponding to the shape of the body of the pressure vessel at the center and an end 2 corresponding to the mirror shape of the pressure vessel at both ends is used, and this is used as a rotary shaft. Attach to 4. Specifically, the fittings 5, 5 are provided on both ends.
A mandrel 3 having
The rotating shaft 4 is inserted through the shaft center of the mandrel 3 so as to pass through the space, and the outer peripheral surface of the rotating shaft 4 is supported by the supporting members 6 and 6.
This is done by fixing each fitting 5, 5 with a bolt 7.
Then, the mandrel 3 is rotated about the rotation shaft 4 as a fulcrum. On the entire outer peripheral surface of the rotating mandrel 3,
The resin-impregnated fibers are wound so as to cross each other obliquely to form the oblique winding layer 8.

Thereafter, in order to compensate for the lack of strength in the circumferential direction in the portion of the oblique winding layer 8 corresponding to the cylindrical portion 1, fibers impregnated with resin are circumferentially applied to the outer peripheral surface of the oblique winding layer 8. The pressure vessel made of FRP is manufactured by winding and superposing the circumferential winding layer 9 on the same portion.

[0005]

However, in such a manufacturing method, when the layer thickness of the circumferential winding layer 9 becomes thicker, "the linear expansion coefficients of the oblique winding layer 8 and the circumferential winding layer 9 in the main axis direction are different" and " The circumferential winding layer 9 has extremely small rigidity and strength in the axial direction of the pressure vessel as compared with the oblique winding layer 8. " There is a problem that molding cracks easily occur in the circumferential winding layer 9 due to the stress in the axial direction of the pressure vessel. For this reason, there is a drawback that the thickness of the pressure vessel cannot be increased, which makes it difficult to manufacture a pressure vessel having a high pressure resistance.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method of manufacturing a pressure vessel made of FRP capable of reducing the stress generated in the circumferential winding layer. It is in.

[0007]

In order to achieve the above object, the method of manufacturing a pressure vessel made of FRP according to the present invention is designed so that the resin-impregnated fibers are obliquely crossed on the outer peripheral surface of the mandrel. After forming the oblique winding layer by winding, a tension is applied to the oblique winding layer along the axial direction of the mandrel, and the outer peripheral surface of the oblique winding layer corresponding to the tubular portion is impregnated with resin. The wound fiber is wound in the circumferential direction to form a circumferential winding layer, and then the tension applied to the oblique winding layer is released according to the curing shrinkage amount of the circumferential winding layer to form the circumferential winding layer. It reduces the stress generated in the layers.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIGS. FIG. 1 shows an apparatus for manufacturing a pressure vessel made of FRP (fiber reinforced plastic) suitable for the method of the present invention.

Here, the manufacturing apparatus will be described. Reference numeral 10 is a rotary shaft rotated by the motor 11 as a drive source. A pair of disk-shaped lids 12, 12 penetrate through both ends of the rotary shaft 11. These lids 12, 12
One of them is fixed to the rotary shaft 11. The other lid 12 is, for example, a spline,
It engages in the circumferential direction and is fixed to the rotary shaft 11 slidably in the axial direction. With such fixing,
Each lid 12, 12 is designed to rotate together with the rotary shaft 10.

Reference numeral 13 is a mandrel. Mandrel 13
Has a hollow portion having a cylindrical portion 14 at the center corresponding to the shape of the body of the pressure vessel to be the product and end portions 15 at both ends corresponding to the mirror shape of the pressure vessel. Further, mouthpieces 16, 16 are provided at the center of each end of the mandrel 13.

These mouth fittings 16 and 16 are the lid 1
The bolts 17a are fitted in the outer peripheral portions of
It is detachably fixed. As a result, the lid 12,
A mandrel 13 is detachably attached around the rotating shaft portion between the two.

On the other hand, the rotary shaft 10 has a cylindrical portion 32a (shown in FIGS. 2 to 4) of an oblique winding layer 32 (layer made of fiber reinforced plastic) formed on the mandrel 13.
In addition, an internal pressure pressurizing type tension applying mechanism 17 for applying pre-tension (tension) along the axial direction of the mandrel 13 is provided. The tension applying mechanism 17 has a structure in which an inflatable rubber film 18, a restraint 19 for restraining radial deformation, and a fluid introduction / extraction mechanism 20 are combined.

That is, the rubber film 18 is formed by the mandrel 13
It is provided around the outer peripheral portion of the rotary shaft 11 facing the inside so as to cover the entire shaft portion. Further, both ends 18a of the rubber film 18 are fastened and fixed by a band 21 to an outer peripheral portion of the rotary shaft 11 facing the inner peripheral surface of the lid 12 as shown in FIG. Specifically, an annular groove 11a for accommodating the end of the rubber film 18 is formed in a part of the outer peripheral portion of the rotary shaft 11, and the rubber film 18 is wound around the bottom of the annular groove 11a. The above portion is fixed by a plurality of bands 21 so that the pressure in the rubber film 18 does not escape from this portion. As a result, as shown in FIG. 2, the rubber film 18 can be expanded in the entire inside of the mandrel 13.

The restraint 19 is a cylindrical portion 1 of the mandrel 13.
4 and a portion of the rubber film 18 corresponding thereto. The restraint 19 has a structure in which a large number of elongated plates 22 arranged in parallel as shown in FIG. 6 and FIG. 7 viewed from the arrow A in FIG. 6 are annularly connected via a hinge 23. ing. The restraint tool 19 is fixed to the rubber membrane portion by a stopper not shown so that it is arranged immediately below the cylindrical portion 14 of the mandrel 13 when the rubber membrane 18 is expanded. Of course, this restraint device 19 includes the cylindrical portion 14 of the mandrel 13.
The diameter is smaller than the inner diameter of the. As a result, the expanding rubber film 18 causes the cylindrical portion 14 of the mandrel 13 to move.
Of the mandrel 13 and the expanding rubber film 18 touches only the both ends of the mandrel 13.

Reference numeral 24 is an elongated plate 2 which constitutes the hinge 23.
Key insertion ports provided at predetermined intervals at both ends of 2
Reference numeral 5 is a key for rotatably connecting the adjacent elongated plates 12 by alternately inserting the key insertion ports 25 of the adjacent elongated plates 22, and by the folding structure of the elongated plates 22 by the hinges 23, a restraint. 19 can be put in and taken out from the mouthpiece 16.

The fluid inlet / outlet mechanism 20 has a fluid inlet / outlet port 26 opening in the rubber film 18 on the outer peripheral surface of the rotary shaft 10. The fluid inlet / outlet 26 is provided with a flow path 27 provided at the axial center of the rotary shaft 10, a joint 29 connecting the flow path 27 provided at the shaft end of the rotary shaft 11 and an external hose 28 (the rotary shaft 11 and the hose). 28 and a rotary shaft 11 are allowed to rotate relative to each other in the rotational direction, and have a function of preventing pressure from leaking to the outside. As a result, the air is pumped from the air pump 30 into the rubber film 18, whereby the mandrel 13
32a of the oblique winding layer 32 formed on the outer peripheral surface of the
In addition, pretension along the axial direction of the mandrel 13 can be applied.

Further, the hose 28 is provided with a three-way valve 31 which opens to the outside air in the middle thereof, so that the pressurized air in the rubber film 18 can be released. That is, the pretension given by the operation of the air pump 30 can be released. Next, the method of the present invention will be described using the FRP pressure vessel manufacturing apparatus configured as described above.

As shown in FIG. 1, with the mandrel 13, the restraint 19 and the rubber film 18 attached to the rotary shaft 11, the motor 11 is operated to rotate the rotary shaft 10. As a result, the mandrel 13 rotates about the axis.

From this state, a fiber-reinforced plastic, that is, a resin-impregnated fiber is wound around the entire outer peripheral surface of the mandrel 13 extending between the metal fittings 16 and 16 so as to cross the entire outer surface of the mandrel 13 at an angle. Then, the oblique winding layer 32 is formed. After the forming, the axial pre-tension of the mandrel 13 is applied to the cylindrical portion 32a of the oblique winding layer 32. This is a three-way valve 31 as shown in FIG.
The air pump 3 by operating the hose 28 in the direction of circulation.
This is done by activating 0.

That is, the pressurized air from the air pump 30 is led out from the fluid inlet / outlet 26 to the rubber film 18 through the flow path 27 as shown in FIG. 2, and expands the rubber film 18.

Since the rubber film portion corresponding to the cylindrical portion 14 of the mandrel 13 is provided with the restraint tool 19, the rubber film 19 is provided on the mandrel portion corresponding to the mirror portion 32b of the oblique winding layer 32. The rubber film 19 is in contact with the mandrel portion corresponding to the cylindrical portion 32a of the oblique winding layer 32.
Do not touch.

By pressing the rubber film 19 against the mandrel 13, the cylindrical portion 32a of the cross winding layer 32 receives only the axial pulling force from the mirror portions 32b on both sides. That is, the pre-tension in the axial direction of the mandrel 13 is applied to the oblique winding layer 32.

Then, in order to make up for the insufficient strength in the circumferential direction of the cylindrical portion 32a of the obliquely wound layer 32, as shown in FIG. 3, the obliquely wound layer 32 is left with the axial pretension applied. A fiber-reinforced plastic, that is, a resin-impregnated fiber is circumferentially wound around the outer peripheral surface of the cylindrical portion 32a, and the circumferential winding layer 33 is superposed on the oblique winding layer 32 to be molded.

Finally, the pre-tension applied to the oblique winding layer 32 is released according to the curing shrinkage amount of the circumferential winding layer 33. Specifically, the pretension release amount is based on the measured temperature of the circumferential winding layer 33 using the correlation data between the shrinkage amount and the temperature of the circumferential winding layer 33 which is grasped in advance.
The release amount at that time is determined. Then, according to the obtained release amount, as shown in FIG.
The pressurized air in the rubber film 18 may be released from the three-way valve 31 as required by operating. In this way, shrinkage deformation of the circumferentially wound layer 33 is not restricted during the cooling and hardening process of the circumferentially wound layer 33. This means that the stress generated in the molded circumferentially wound layer 33 is reduced. Therefore, it is possible to prevent the molding crack of the circumferential winding layer 33 due to the residual stress of formation of the circumferential winding layer 33. Therefore, it is possible to increase the thickness of the FRP pressure vessel, and it is possible to manufacture the FRP pressure vessel having a higher withstand pressure than the conventional one.

In one embodiment, the internal pressure of the pressure vessel is increased to provide the pretension, but the pretension may be provided by a mechanical method of pulling the cylindrical portion 32a of the cross winding layer 32. . In this case, as shown in the schematic view of FIG. 8, a load may be applied to the mirror portion 32b of the oblique winding layer 32 to pull the cylindrical portion 32a of the oblique winding layer 32 in the axial direction.

[0026]

As described above, according to the present invention,
The stress generated in the formed circumferentially wound layer can be reduced. Therefore, it is possible to prevent molding cracks in the circumferential winding layer due to residual stress in the formation of the circumferential winding layer. As a result, it is possible to increase the thickness of the FRP pressure vessel,
An FRP pressure vessel having a high pressure resistance can be manufactured.

[Brief description of drawings]

FIG. 1 is a view for explaining a first step of manufacturing an FRP pressure vessel according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a step of applying pretension after forming the obliquely wound layer.

FIG. 3 is a diagram for explaining a step of forming a circumferential winding layer on a cylindrical portion of the oblique winding layer to which the printing tension is applied.

FIG. 4 is a diagram for explaining a step of releasing the pretension.

FIG. 5 is a cross-sectional view showing a mounting structure of a rubber film for giving pretension to a rotating shaft.

FIG. 6 is a perspective view showing the structure of a cylindrical restraint used to apply pretension only in a predetermined direction.

FIG. 7 is a view showing a part of the outer periphery of the restraint tool as seen from the direction of arrow A in FIG.

FIG. 8 is a diagram showing another embodiment of the present invention.

FIG. 9 is a view for explaining a method of manufacturing an FRP pressure vessel using the conventional FW method.

[Explanation of symbols]

10 ... Rotating shaft, 13 ... Mandrel, 14 ... Cylindrical part, 15
... end portion, 17 ... tension applying mechanism, 18 ... rubber film, 19 ... restraint tool, 20 ... fluid inlet / outlet port, 26 ... fluid inlet / outlet port, 28 ...
Hose, 30 ... Air pump, 31 ... Three-way valve, 32 ... Oblique winding layer, 33 ... Circular winding layer.

Claims (1)

[Claims] 1. An outer peripheral surface of a mandrel having a cylindrical portion corresponding to the shape of the body of the pressure vessel at the center and an end corresponding to the mirror shape of the pressure vessel at the end is impregnated with resin. The oblique winding layers are formed by winding the twisted fibers so as to cross each other at an angle, and then, with the tension applied to the oblique winding layers along the axial direction of the mandrel, the tubular portion of the oblique winding layers is formed. A resin-impregnated fiber is wound in the circumferential direction on the outer peripheral surface corresponding to to form a circumferentially wound layer, and then the tension applied to the oblique winding layer is applied according to the curing shrinkage amount of the circumferentially wound layer. A method of manufacturing a pressure vessel made of FRP, characterized by releasing the pressure vessel.