JPH0482727A - Frp product - Google Patents

Abstract

PURPOSE:To provide an FRP product showing excellent mechanical strength and withstanding high loading force by specifying the relation between the diameter D of an eyeball part winding fiber layer and the distance (l) of the fiber unfilled part from an eyeball part to a shaft part to 0.1 <l/D < 0.4. CONSTITUTION:'The diameter D of an eyeball winding fiber layer' means the outer diameter of the cylindrical fiber layer formed by the fiber wound around the entire periphery of an eyeball part and 'the length (l) of a fiber unfilled part' means the distance from the bottom side on a cylindrical part when the shape of the fiber unfilled part is regarded as an almost equilateral triangle to the apex on the side of a shaft part. The FRP product satisfying this condition is obtained by controlling the ratio of the fiber wound around an eyeball part 8 and the fiber arranged between the eyeball part and the shaft part 9 and setting the shape of a molding surface, exactly, the shape of the molding surface of the branch part 6 of a mold. As the resin infiltrated in the fibers, a thermosetting resin such as an epoxy resin or an unsaturated polyester resin like vinyl ester is designated. As the fibers, a glass fiber, a carbon fiber or an aramid fiber is used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an FRP product having a shaft portion and a center portion, such as an FRP suspension arm for an automobile.

(Conventional technology) To reduce the weight of automobiles, suspension arms are also
RP (fiber reinforced plastic)
Attempts have been made to make them from fiber-reinforced plastic (sticks: fiber-reinforced plastic). As shown in section 9, the suspension arm 1 (upper arm) has eye parts 8, 8 for rubber bushes 2, 2, etc. at the end, so this is made of FRP.
When manufacturing with a sleeve 12 for a bushing, as shown in FIG.
It is advantageous in terms of productivity to manufacture the wire by wrapping it around the ball joint assembly 12 and the ball joint assembly 13 as appropriate and arranging it between them (winding).

The sleeve 12 is provided with flanges 14 and 14 at both ends to prevent the fibers 11 from coming off, and the above-mentioned continuous fibers are made into long fibers by aligning and bundling reinforcing fiber filaments such as carbon fiber filaments and glass fiber filaments. As shown in Fig. 4, the basic pattern for winding is a pattern in which each sleeve 12.12 is wound and the ball joint assembly 13 is passed (
I), pattern (J) of winding around each sleeve 12.12 and assembly 13, winding around each sleeve 12.12 and assembly 1 alternately in opposite directions in assembly 13;
3. Passing pattern (G), each sleeve 1 in a constant rotation.
2.12 and the assembly 13 have a pattern (E), each sleeve 12.12 has a pattern (F) in which the hook is passed and the assembly 13 is wound.

And FRP products are FR obtained by winding.
The P fiber bundle is then molded using an upper die 15, a lower die 16, a middle die 17, etc. as necessary, as shown in FIG. 5, in order to improve dimensional accuracy, stabilize quality, and improve strength and rigidity. can get.

Such a method is known as a filament winding method, and for example, Japanese Patent Laid-Open No. 58-118215 discloses a method for manufacturing FRP products having eyelets such as leaf springs and connecting rods using this method.

(Problems to be Solved by the Invention) When an FRP product having a shaft portion and an eye portion is manufactured by the filament winding method as described above, as shown in FIG. A fiber-unfilled portion 3 is created in the branch portion 6 . Since the strength of the FRP product decreases as the fiber-unfilled area increases, the FRP fiber bundle obtained by winding is compression-molded with a mold so as to eliminate the fiber-unfilled area as much as possible.

However, in this case, the compression molding forces the fibers in the vicinity of the non-fiber-filled portions, resulting in fiber breakage and failure to improve the strength as desired. For example, FRP suspension arm 1
(see FIG. 9), there is a possibility that breakage will occur at the boundary between the shaft portion 9 and the eyepiece portion 8 when subjected to a high tensile load, which has prevented the practical use and widespread use of FRP suspension arms.

The present invention was made for the purpose of solving the problem of insufficient strength of FRP products due to the above-mentioned fiber-unfilled areas, and the problem to be solved is to
To provide an FRP product with a new structure that exhibits high strength even when the P product is manufactured by a filament winding method.

(Means for Solving the Problems) FR having a shaft portion and an eye portion of the present invention manufactured by a filament winding method to solve the above problems.
For P products, the relationship between the diameter of the fiber layer wound around the eye and the length β of the unfilled fiber layer from the eye to the shaft is o,t<J2/D<0.4. Features.

Here, the "diameter D of the fiber layer wound around the eyeball" refers to the outer diameter of the cylindrical fiber layer formed by the fibers wound around the entire circumference of the eyeball, and the length "i" of the unfilled fiber layer. refers to the distance from the base of the cylindrical part to the apex of the shaft part when the fiber-unfilled part is regarded as a substantially isosceles triangle.

FR that satisfies the above condition of 0.1<2/D<0.4
P products depend on appropriately adjusting the ratio of the fibers wound around the eye and the fibers arranged between the eye and the shaft.
This is mainly achieved by appropriately setting the shape of the mold surface, specifically the shape of the branch molding surface of the mold. Specifically, the branch molding surface of the mold may be a curved surface drawing an arc with radius R2, and R2 may satisfy the condition that h is the thickness of the shaft portion of the FRP product.

This will be explained with reference to FIG. The outer surface of the fiber layer 5, which is passed from the eyepiece part 8 to the shaft part 9 and from the shaft part 9 to the eyepiece part 8, has an arc with a radius R2 centered on point E. , the inner surface draws an arc with radius R1 centered on point E, and the diameter of the eyeball-wound fiber layer is D = (outer diameter of sleeve) + (sleeve-wound fiber layer) x 2, and the radius is The circle R1 is in contact with the diameter circle and also in contact with the center iJX. Let those points of contact be B and C, respectively, and let the center of the circle with the diameter be A, then in △AEC, AE" = EC"
+AC” (/EcA=/R) holds, that is, since R2 of the product is the same as R2 of the mold,
When the thickness of the shaft portion of the FRP product is h, the following formula holds: h R2=R, --...■. However, formula (■) only holds true when the fiber volume content Vf at the branch part is the same as Vf at the shaft part.
It is possible to make both Vf the same by moving the position of the sleeve during compression molding to loosen the fibers.

Transforming the formula ■, we get ', DR+ = l'' + Di2, and by substituting o, ID < g < 0.4D, which is derived from the condition 0, 1 < β / D < 0.4 in the above 2, into this formula ■. , the range of R8 is 0.11D<R,<0.56D...
... becomes ■. Since there is a relationship between R3 and R2 as shown in the formula (■), the range of R2 can be derived from the formulas (■) and (■) as follows: h h hO, 11D-
-<R・-1<0.56D-ding h
ho, 11D --< R2 < 0.56D -- Note that it is preferable that the following is true.

The pressure during compression molding is 1 to 30 kgf/cm'
However, when using a resin for filament winding with low viscosity, 1 to 1 Okgf/cm" is sufficient. During compression molding, the volume ratio of fiber and resin should not be changed by winding. F
It is important to remove the tension from the RP fiber bundle before molding.

The resin to be impregnated into the fibers may be a resin for FRP, such as an epoxy resin, an unsaturated polyester resin such as vinyl ester, or a thermosetting resin such as a phenol resin. On the other hand, common fibers for reinforcing plastics such as glass fibers, carbon fibers, and aramid fibers are sufficient as the continuous fibers. It is appropriate that the volume content Vf of the fibers during winding is 40 to 60%.

Examples of products having a centerpiece and a shaft to which the present invention can be applied include suspension arms, connecting rods, leaf springs, and the like.

(Function) The smaller ff/D is, the more forcefully the fiber must be bent with the mold, the strain becomes larger and the fiber breaks, which reduces the strength, but within the range of 0.1<42/D. Since the fibers do not need to be bent much during molding, there is no decrease in strength due to fiber breakage.

On the other hand, as ff/D increases, the fiber-unfilled area becomes larger and the strength deficiency becomes more pronounced.However, in the range of ρ/D<0.4, the fiber-unfilled area is not so large and the required strength is Secured.

(Example) An embodiment of the present invention will be described below.

When manufacturing an FRP suspension arm using a device that winds resin-impregnated continuous fibers 11 in a predetermined pattern between a bushing sleeve 12° 12 and a pole joint assembly 13 as shown in FIG. 12. Move the ball joint assembly 13 by about 10) from the normal position of the pillars 4, 4 that determine the position of 12.
Shift it to the opposite side (in the direction where the arm becomes longer) and fix it.

Next, the resin-impregnated continuous fibers 11, which are made by passing glass fibers (4 pieces equivalent to 4400 Tex) through an impregnating tank and impregnating them with resin, and removing excess resin with a die (ceramic yarn mill), are wound into various windings as shown in FIG. In the combination of times pattern E, J, G, E, F, i.e., I+ (J+I)X2+ (
G+E+F-+-E+G+E) Repeat X3+E to wind as many times as necessary.

After winding, move the column 4.4 (see Figure 5) that determines the position of the sleeve 12.12 to its normal position, and
The tension of the RP fiber bundle is removed. Next, the lower mold 16 is pushed upward, and the FRP fiber bundle obtained by winding is stuffed into the groove 7 provided in the lower mold 16, and the upper mold 15 and the middle mold 17 are covered and compression molded. . As shown in FIG. 1, the upper mold 15 and lower mold 16 used here both have a branch molding surface that is a curved surface with a radius R3, and the size of R2 is 0.14D-h/2. <R, <0.56D-h/2 and
It is set to satisfy the following condition: 1<R2 (wherein, D represents the diameter of the fiber layer wound around the center portion, and h represents the thickness of the shaft portion).

As described above, by compression molding at a pressure of about 7 kgf/cm'' and curing the resin at 100° C. for 2 hours, an FRP suspension arm with even higher strength than the conventional one can be obtained.

Test Example As shown in Fig. 7, a tensile load F was applied to various test pieces with different ratios of the diameter of the unfilled fiber layer: D = 25 mm. I2 at the time of
The relationship between /D and the maximum load index (calculated assuming that the applied load value when ff/D=0.8 is 1.0) was investigated. The smaller ff/D is, the more likely damage is to occur due to fiber breakage, and ff
It was confirmed that the larger /D is, the more likely the breakage occurs from the tip of ε (shaft side end of unfilled portion 3), and the results are shown in FIG.

From this Fig. 8, when fi/D<0.4 and ff/D
>1.0, the test piece is likely to break, and A
It can be seen that /D should be set as 0.1<2/D<0.4.

(Effects of the invention) As is clear from the above explanation, the FRP product of the present invention has
Since the fiber-unfilled area does not become large or the strength decreases due to fiber breakage during molding, it exhibits excellent mechanical strength and can withstand even higher load forces. .

This improvement in strength expands the range of applications of FRP, and for example, it becomes possible to use FRP to make automobile parts that have metal eyeballs and shafts. It can greatly contribute to

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of an FRP product and mold according to an embodiment of the present invention, Fig. 2 is an explanatory view of the dimensional relationship of each part of the FRP product, and Fig. 3 is a perspective view showing a winding device. , Fig. 4 is a diagram showing the basic patterns of various windings, Fig. 5 is a perspective view showing the forming method, Fig. 6 is an explanatory diagram of the problems of conventional FRP products, and Fig. 7 is an explanation of the strength test method. Figure 8 is a graph showing the relationship between ff/D and maximum load index according to the test results, and Figure 9 is a perspective view showing the suspension arm. In the figure: l...Suspension arm, 3...Fiber unfilled part, 4-river support, 6...Branch part, 8...Eye part, 9...Shaft part, 11...Resin impregnation Continuous fiber, 15...Upper mold, 16...Lower mold, D...Thickness of the fiber layer wound around the eye, β...Length of the non-fiber filled part, h...Shaft part thickness. Patent Applicant Toyota Motor Corporation Agent Patent Attorney Yumi Sakai (2 others) Figure Figure 6 Branch Figure 6 Figure 8 Eyepiece 9 Axis Group Figure 7 Figure 8 α1 Bias jli 0.7 ■ ■ 1/D Figure 9

Claims (1)

[Claims] In an FRP product having a shaft part and an eye part manufactured by the filament winding method, the diameter D of the fiber layer wound in the eye part and the length l of the unfilled fiber part from the eye part to the shaft part.
An FRP product characterized in that the relationship is 0.1<l/D<0.4.