JPH01168434A - Forming method for frp laminated bent tube - Google Patents

Abstract

PURPOSE:To accurately form an FRP bent tube by rotating a bent tube mandrel around an axis in a reference plane and moving a feeding eye in a three- dimensional manner. CONSTITUTION:A winding line 11 to be wound with tension without sliding fiber is obtained on a mandrel 10, and equally divided to obtain the coordinates of dividing points A, B,.... The number of divisions is increases as much as possible so as to wind the winding line along the fiber as correct as possible. The mandrel 10 is rotated at an angle (theta), and a feeding eye is moving to the coordinates (x2, y2, z2), thereby winding the fiber on BC. Then, a point D' is obtained with respect to the DC, and a similar operation is repeated, thereby forming an FRP laminated bent tube. Since the rotating angle of the mandrel and the selection of the movement of the eye have the degree of freedoms, the line can be accurately wound at a web where an error easily occurs to wind the tube.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming an FRP laminated bent pipe using the FW method.

[Prior Art] Conventional methods for molding FRP bent pipes, such as elbows, include: 1) Extrusion injection molding using short fibers.

2) Shrimp joint method, in which straight FRP pipes are cut diagonally and joined together.

3) Hand lay-up method, in which FRP layers are manually laminated and molded onto a curved tube core.

4) Roving (fiber) by rotating the curved pipe core around the axis
How to wrap.

5) A method of moving and winding a robot arm with multiple degrees of freedom around a fixed bent pipe mandrel.

etc. were being carried out.

[Problems to be Solved] However, each of the above conventional techniques has the following problems.

1) It is a collection of short fibers, and the tensile strength of reinforcing fibers cannot be effectively utilized, so sufficient strength cannot be obtained.

2) Since the fibers are discontinuous at the joint, the strength decreases even if reinforcing winding is applied from above.

3) Manual work, low productivity and high cost.

4) Unlike when winding an axisymmetric type such as a straight pipe, the axis of a bent pipe does not coincide with the axis of rotation, making it difficult to mechanize and winding by hand is the mainstream. Therefore, it is difficult to wind evenly, and since the fibers enter mainly in the circumferential direction, the hoop strength is high, but the axial strength is low.

5) Since the mandrel is fixed and wound, there are problems such as more unnecessary movement than when the mandrel is rotated and wound.

It is an object of the present invention to provide a method for forming a laminated curved pipe made of FRP that can solve the above-mentioned problems.

[Means for Solving the Problems] The method for forming a laminated bent pipe made of FRP of the present invention sets a reference plane including the rotational axis of the bent pipe mandrel, and the bent pipe rotates about the rotational axis. A rotationally symmetrical closed curved surface centered on the rotational axis is set, which includes a rotating body formed by the mandrel, and the bent pipe mandrel is arranged with its tube axis direction parallel to the rotational axis in the reference plane. In addition to finding a winding wire that can be wound on the mandrel under tension without causing the fiber to slip, this winding wire is divided into a large number of parts in advance, and the tangent line of the fiber to be wound at one division point on the winding wire is Find the position (xl, yl, zl) of this point in the orthogonal coordinate system including the reference plane of the point that intersects with the closed surface, position the feed eye here, and then The coordinates (x2, y2, z2) of the point where the tangent intersects with the cylindrical surface are set at an arbitrary angle (θ
) Find it on an orthogonal coordinate system including the rotated new reference plane, rotate the mandrel by the above angle (θ), and move the feed eye to the above coordinates (x2, y2, z2) to wind the fiber, The method is characterized in that the above-mentioned operation is then repeated at the next dividing point to form an FRP laminated bent pipe.

[Operation] An FRP bent pipe can be formed by rotating the bent pipe mandrel around the rotation axis in the reference plane and moving the feed eye three-dimensionally. In this case, since there is a degree of freedom in selecting the rotation angle of the mandrel and the movement of the feed eye, it is possible to wind the bent pipe with high precision in the abdomen where errors are likely to occur when winding.

In addition, the three-dimensional movement of the feed eye and the rotation of the mandrel are controlled by a computer and operated by a program, saving labor, time, and increasing precision.
It can be rolled with cheaper equipment than using a robot.

[Example] Hereinafter, an example of the method of the present invention will be described with reference to FIGS. 1 and 2.

Reference plane 1 including the rotation axis T-T of the bent pipe mandrel 10
Set.

Further, considering a rotating body formed by the bent pipe mandrel 10 that rotates around the rotation axis T-T, on the other hand, a rotationally symmetric closed surface that includes the rotating body with a closed curved surface centered on the rotation axis Set curved surface 5. This closed curved surface is formed by connecting hemispherical surfaces 7 to both sides of the cylindrical surface 6.

Then, as a starting condition, the bent pipe mandrel 1
0 is arranged at a position perpendicular to the reference plane 1 with its tube axis direction parallel to the rotation axis.

The plane in which the feed eye moves is considered to be on the reference plane 1.

A winding wire 11 that can be wound on a mandrel 10 under tension without the fiber slipping is found, and this winding wire is equally divided to find the coordinates of dividing points A, B, . . . . Here, the number of divisions is made as large as possible so that the fiber can be wound as accurately as possible along the winding wire.

First, A and B are close to each other so that AB is extended toward B.
Find a point B' that intersects with the closed curved surface 5 (substantially a tangent). Then, the position (x7, yl, zl) of this point in the orthogonal coordinate system including the reference plane 1 is determined, and the fiber is wound between AB by moving the feed eye to this point.

Next, extend BC toward C, and point C' where it intersects with the closed surface 5.
seek. Then, the coordinates of this point (x2, y2, z2
) is determined on an orthogonal coordinate system including a new reference plane 2 obtained by rotating the reference plane 1 by an arbitrary angle (θ). ”1 Angle (θ)
If the winding is divided into n parts, for example, 360°
/n.

Then, the mandrel 10 is rotated by the above angle (θ), and the feed eye is moved to the above coordinates (x2, )/2, Z2.
) to wrap the fibers onto the BC.

Thereafter, by determining the D' point with respect to CD and repeating the same operations as above, an FRP laminated bent pipe can be formed.

In the above example, the closed curved surface 5 is formed by connecting the hemispherical surface 7 to the cylindrical surface 6, but the surface connected to the end of the cylindrical surface 6 is a flat surface 8, as shown in FIG. It may also be a conical surface 9. As shown in the figure, a reducer or the like is used at the folded portion at the end of the bent tube, but the moving point of the feed eye differs depending on the shape of the end surface. That is, the feed eye moves to Q' on the plane 8, Q' on the hemispherical surface 7, and Q' on the conical surface 9.

Therefore, an appropriate end face shape may be selected depending on the shape of the folded portion. In addition, the closed curved surface 5 may be oval-shaped as a whole.

Further, in the above embodiment, the reference plane is rotated at a constant angle to obtain a new reference plane, but it may be rotated by any angle.

[Effects of the Invention] The method for forming a laminated bent pipe made of FRP according to the present invention is as described above, and a bent pipe can be formed by rotating a bending pipe mandrel and moving a feed eye in a three-dimensional direction. Further, since there is a degree of freedom in selecting the rotation angle of the mandrel and the movement of the feed eye, it is possible to wind the bent pipe with high precision in the abdomen, where errors tend to occur when winding the pipe. Furthermore, by programming the above operations and controlling the rotation of the mandrel and the movement of the feed eye by computer, labor and time savings and high precision can be achieved, and winding can be performed with cheaper equipment than using a robot.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing an example of a procedure for carrying out the method of the present invention, and FIG. 3 is an explanatory diagram showing another example of a closed curved surface. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A reference plane including a rotation axis of a bent pipe mandrel is set, and the rotation axis includes a rotating body formed by the bent pipe mandrel that rotates around the rotation axis. A rotationally symmetrical closed curved surface is set as the center, and a bent tube mandrel is arranged with its tube axis direction parallel to the rotation axis in the reference plane, so that the fiber can be wound on the mandrel under tension without slipping. In addition to finding the winding wire, this winding wire is divided into a large number of parts in advance, and this point in the orthogonal coordinate system including the reference plane of the point where the tangent at one dividing point on the winding of the fiber to be wound intersects with the closed curved surface is determined. Find the position (x_1, y_1, z_1), position the feed eye here, and then find the coordinates (x_2, y_2, z_2) of the point where the tangent at the next dividing point on the winding intersects with the cylindrical surface. is obtained on a Cartesian coordinate system including a new reference plane obtained by rotating the above reference plane by an arbitrary angle (θ), rotate the mandrel by the above angle (θ), and set the feed eye to the above coordinates (x_2, y_2, z_2). A method for forming a laminated curved FRP pipe, characterized in that the FRP laminated curved pipe is formed by moving and winding the fibers, and then repeating the above operation at the next dividing point.