JPS61130605A - Fiber reinforced plastic bolt - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fiber reinforced plastic (FRP) bolt used for mechanical structures.

(Prior art) Conventionally, the material for bolts for mechanical structures is FRP round bars as shown in Figure 2, which are made by aligning glass fibers in one direction and drawing them into a mold while impregnating them with resin. It is called FRP round bar.

In FIG. 2, 1 is a glass reinforcement material, and 2 is its cross section.

However, in the case of drawn FRP nine rods, the glass fiber which is the reinforcing material is arranged in the length direction of the drawn FRP round rod and not in the radial direction, so when it is processed into an F'RP bolt using this, it is shown in Figure 3 a and b. As shown, there is no glass fiber reinforcement in the thread (radial direction of the bolt), which increases the strength of the thread
There are limits to its use as an RP bolt. In the figure, 3 is a cross section of the glass reinforcement material, 3 is an FRP bolt, and 4 is a circle showing the diameter of the threaded portion of the bolt. Therefore, for this type of use, it has conventionally been common to cut a laminated plate made of glass cloth reinforced in the vertical and horizontal directions into a rod shape as shown in FIG. 4. In the figure, 5 indicates an FRP bolt, and 6 indicates a weft thread. However, FRP bolts made using this method also have drawbacks.

In other words, since the base material of the laminate is glass cloth reinforced in the same proportion in the vertical and horizontal directions,
As shown in b, the amount of glass base material in the longitudinal direction is drawn from FRP.
It is smaller than a round bar, and when processed into an FRP bolt, the tensile strength of the bolt will be weaker than an FRP bolt obtained by processing a drawn F'R, P round bar. In the figure, 4 is a circle indicating the thread diameter of the bolt, 5 is an FRP port, 6 is a weft thread,
7 is a warp thread.

However, the thread strength of this Fll'LP bolt is improved over bolts made from drawn FFLP round bars because the thread direction (radial direction of the bolt) is reinforced with glass fiber as shown in FIG.

(Objective of the Invention) The object of the present invention is to provide an FRP bolt which improves all the drawbacks of conventional FRP bolts in terms of mechanical strength and has a balance between thread strength and longitudinal tensile strength.

(Structure of the Invention) The present invention provides that the length direction of the blind weave roping cloth is 90 degrees.
This invention relates to PR and P bolts obtained by cutting from glass laminates that have been laminated with different degrees of deviation and then impregnated with a thermosetting resin composition and cured.

The blind weave roping cloth in the present invention has a weight ratio of warp to weft (warp/weft) of 5/1 or more.

In the present invention, we used blind weave roping cloth as a reinforcing material in the laminate, devised a laminating method, and varied the ratio of the amount of glass thread in the vertical and horizontal directions of the laminate to increase the thread strength when processed into FRP bolts. The objective is to balance the tensile strength of the bolt with the tensile strength of the bolt. That is, when laminating the blind weave-big cloth, as shown in FIG. 1, the length direction of the blind weave roping cloth is shifted by 90 degrees so that the rovings are perpendicular to each other. In the figure, 8 is a warp thread, 9
is the weft thread. In the present invention, ideal strength characteristics as an FRP bolt can be maintained by changing the stacking ratio by shifting the layers by 90 degrees.

When the roping cloths are stacked at right angles, □( When processed into an FRP bolt as shown in Figure 6.

Contributes to improving the strength of the screw thread. FRP bolts will also be reinforced with glass fiber in the radial direction.

In the figure, 4 is a circle indicating the thread diameter of the bolt, 8 is a warp thread, and 10 is an FRP bolt. Note that the blind roping cloth is a glass fabric made of glass roving in either the vertical or horizontal direction and glass yarn in the other direction. For example, part name WR, -74ON1000C8 (
(manufactured by Nittobo Co., Ltd.).

The type of thermosetting resin composition is not particularly limited and conventional materials can be used. Impregnation and curing methods for thermosetting resin compositions include a method of press molding ordinary Gripreg, and a voidless molding method in which a glass cloth is placed under reduced pressure, impregnated with the thermosetting resin composition, and heated and cured under pressure. Adopted (Effects of the Invention) According to the present invention, it is possible to obtain an FRP bolt with balanced thread strength and tensile strength.

(Example) An example will be explained. Parts are by weight.

Example: Blind weave roping cloth (WR-7 manufactured by Nittobo Co., Ltd.)
40-100ON) with a width of 1000m as shown in Figure 1.
The sample was cut into pieces with a length of 1,000 m and was subjected to WtM at the ratio shown in Table 1, with the length direction shifted by 90 degrees. The number of laminated sheets is 25% thick so that the amount of glass in the laminated sheet is 80%.
It was set as 65 sheets for ann. The laminated product was placed in a mold and the mold was tightened to a thickness of 25ITIT11, and then the entire mold was placed in a vacuum tank and vacuum dried. Thereafter, an epoxy resin composition having the formulation (parts by weight) shown in Table 2 was injected under vacuum, and then heated at 70°C for 15 hours and at 120°C for 6 hours.
A laminate was formed by heat curing for several hours. FRP bolts (M22 stud bolts with a length of 120 ann) were fabricated from the obtained laminate and subjected to a strength test.

Note) Vertical refers to the length direction of the bolt when processed into an FRP bolt. Horizontal refers to the radial direction of the bolt when processed into an FRP bolt.

Table 2 The test method is shown in FIGS. 7 and 8.

FIG. 7 shows a method of testing the thread strength of a bolt by applying a load P from the top and determining the load at which the thread of the F'RP bolt 11 screwed into the iron nut 12 breaks. 13 is a jig.

Figure 8 shows a method of testing the tensile strength of the threaded portion of the bolt using a bolt model. A tensile load P was applied to both ends of the model using a tensile testing machine to determine the load at which the FRP bolt 14 would break at the threaded portion. .

As shown in the test results in Table 3, by stacking blind weave roping cloth with the length and width directions shifted by 90 degrees, the thread strength as an FRP bolt and the tensile strength as a bolt are more balanced than in the comparative example. I know that there is.

Comparative Example 2 Plain woven glass cloth (manufactured by Nittobo Co., Ltd., symbol WE-18-1104BX) was used as a glass reinforcement material with a width of 11000a+
, cut into lengths of 1,000 mm, stacked 165 sheets, put them into a mold, tightened the mold to a thickness of 25 m, and then put the entire mold into a vacuum tank.

A laminate was then molded in the same manner as in the example. This laminate was processed into an FRP bolt and subjected to a strength test. The results are shown in Table 3. Comparative Example 2 obtained a result that the tensile strength was weaker than the thread strength compared to the Example.

Comparative Example 3 Inside a brass pipe with an inner diameter of 25 m and a length of 1000 ann
), 342 pieces of glass roving (R8-240E-601 manufactured by Nittobo Co., Ltd.) were bundled and pulled into a vacuum tank, and heated and hardened under the same conditions as in the example below to obtain a diameter of 25 aon + length of 11000 a + drawn F'RP. A round bar was formed. This was processed into an FRP bolt and subjected to a strength test.

As shown in Table 3, the results showed that the tensile strength was strong but the screw thread strength was weak compared to Examples and Comparative Example 2.

The FFLP bolt according to the present invention has improved thread strength and tensile strength compared to FR and P bolts using glass cloth laminates. In addition, using a drawn FRP round bar, fc
Compared to FRP bolts, the thread strength has been improved to a maximum of 500 inches.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the method of laminating the blind weave roping cloth used in the present invention, Figure 2 is an outline diagram of a drawn FRP round bar, and Figures 3 a and b are FBs obtained by cutting from a drawn FRP round bar.
, Figure 4 is an outline diagram of the FRP nine bars obtained by cutting from a glass laminate, and Figures 5 a and b are obtained by cutting using the round bar shown in Figure 4. External diagram of FRP bolt, Figures 6a and b are external diagrams of FRP bolt according to the present invention,
FIG. 7 is a diagram showing a method of testing the thread collapse strength of an FRP bolt, and FIG. 8 is a diagram showing a method of testing the tensile strength of an FRP bolt. Explanation of symbols 1...Glass strengthening agent 2...Cross section 3...FRP
Bolt 4...Circle indicating the diameter of the threaded part of the bolt 5...PR, P bolt 6...Weft thread 7...Warp thread 8...Warp thread 9...Weft thread 10... PR, P bolts 11...FF according to the present invention
LP bolt 12... Iron nut 13... Jig
14...FII, P Bolt 1st Cheer 30 ¥40 Good b (Revised?

Claims (1)

[Claims] 1. An FRP bolt obtained by cutting from a glass laminate plate in which blind weave roping cloth was laminated with the longitudinal direction shifted by 90 degrees and then impregnated with a thermosetting resin composition and cured.