JPS61144435A - Frp tapered leaf spring - Google Patents

Abstract

PURPOSE:To prevent local generation of portions of much resin by cutting end face of reinforced fiber flux of a core previously and enabling extrustion of resin. CONSTITUTION:An end face 1C of a reinforced fiber flux 1 of a core unit 12 is cut slantly at an angle of theta of 45 deg. or less desirably to the longitudinal direction without cutting at a right angle to the longitudinal direction of a leaf spring. Thus, as the end face 1c of fiber flux of the core unit 12 is cut slantly, tip portions are easily smashed when end portions are pressued in squeezing and excessive resin is easily extruded. Then, generation of portions where mush resin is remained locally can be prevented.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is directed to
Regarding RP taper leaf spring.

[Conventional technology]

A major advantage of FRP leaf springs is that they are lightweight. However, if the width and thickness are made the same over the entire length of the leaf spring, the stress at each part in the length direction becomes unequal and material usage efficiency decreases, making it impossible to achieve sufficient weight reduction.

Therefore, it is desirable to equalize stress by creating a shape in which the thickness of the plate is thick at the central portion in the length direction, and the thickness of the plate is tapered and thinned at the end sides.

Conventionally, tapered leaf springs have been developed for steel springs from the above viewpoints. However, there are few prior arts disclosing tapered leaf springs made of FRP.

For example, in the prior art illustrated in FIG. 4, a tapered leaf spring is obtained by impregnating a plurality of reinforcing fiber bundles 1.2 with resin and stacking them in the thickness direction. After the fiber bundle 1.2 is wound up in a mold, it is pressed down in the thickness direction and squeezed to remove excess resin before hardening.

[Problem that the invention seeks to solve]

As shown in FIG. 5, the plural reinforcing fiber bundles 1 having different lengths are generally cut at the end face 1a of the fiber bundle 1 at a right angle to the longitudinal direction of the plate.

However, in the case of the above laminated structure, a step is created between the end face 1a of the short fiber bundle 1 and the long fiber bundle 2, as shown in FIG. As a result, in the process of squeezing the fiber bundle to remove excess resin,! ! ff1 The end of bundle 1 is not crushed enough and resin remains, and there is a localized area with a large amount of resin 3
The inventors' research has revealed that this occurs, causing a decrease in the strength of the leaf spring.

[Means for solving problems]

The present invention provides an FRP tapered board comprising an outer layer portion made of a reinforcing fiber bundle impregnated with a resin, and a core portion made of a reinforcing fiber bundle shorter than the outer layer portion impregnated with a resin and covered by the outer layer portion. Applied to springs. In the FRP tapered leaf spring of the present invention, the end face of the reinforcing fiber bundle in the core part is not cut perpendicularly to the longitudinal direction of the leaf spring, but is cut diagonally or tapered so that the width on the tip side gradually decreases. It is characterized by being cut in advance.

[Function] The above FRP tapered leaf spring is made into a tapered shape (to obtain a 75 FRP leaf spring) by impregnating the reinforcing fiber bundles constituting the outer layer portion and the reinforcing fiber bundles constituting the core portion with resin and stacking them in the thickness direction. be able to.

The end surfaces of the reinforcing fiber bundles in the core section are cut in advance in a diagonal or tapered shape, so in the process of squeezing these fiber bundles to remove excess resin, the ends of the fiber bundles in the core section are pressed down. When this happens, the ends tend to collapse and the resin tends to be extruded. Therefore, it is possible to prevent or reduce the occurrence of local areas with a high resin content, and also to reduce air bubbles, which is effective in preventing a decrease in strength.

[Embodiments of the invention]

In one embodiment shown in FIGS. 1 and 2, the FR
The P-taper leaf spring 10 has a tapered shape in which the plate thickness is thickest near the central portion in the longitudinal direction and the plate thickness gradually decreases toward the plate ends. Furthermore, the plate width is uniform over the entire length.

The leaf spring 10 includes an outer layer 11 and a core 12 embedded in the center of the outer layer 11.

The outer layer portion 11 is made by impregnating a unidirectional continuous reinforcing fiber bundle, for example, a continuous glass fiber bundle, along the longitudinal direction of the leaf spring with a matrix resin and hardening it.

The core part 12 is also reinforced in one direction along the longitudinal direction of the leaf spring.
Although the bundle is impregnated with a matrix resin and cured, the length of the reinforcing fiber bundle in the core part 12 is shorter than that in the outer layer part 11, and is cut in advance.

The core portion 12 is formed into a tapered shape by stacking a plurality of fiber bundles 1 having different lengths vertically with the central portion in the thickness direction as the boundary, similar to that shown in FIG. Note that the reinforcing fibers and resin used for the core portion 12 are the same as those used for the outer layer portion 11. However, reinforcing fibers other than glass fibers may be used.

The reinforcement of the core portion 12 [I41] The end face 1C of the bundle 1 is not cut perpendicularly to the longitudinal direction of the leaf spring, as illustrated in FIG.
It is cut diagonally at an angle θ of 5° or less.

The FRP tapered leaf spring 10 having the above structure can be formed by a filament winding method. For example, after winding a predetermined layer of continuous reinforcing fiber bundles that will become the outer layer portion 11 around a mold (not shown) located on the upper side of the figure in FIG. 1 in sequence. After stacking the core parts 12 in this way, the remaining part (the lower surface of the core part 12 in the figure)
The continuous reinforcing fiber bundle 2 of the outer layer portion 11 is rolled up. It goes without saying that these reinforcing fiber bundles are impregnated with resin in advance. After winding it up into a mold, it is squeezed from the outside to remove excess resin and allowed to harden.

The FRP tapered leaf spring 10 having the above structure is used, like a general leaf spring, with its end portion attached to the vehicle body side and the longitudinally intermediate portion attached to the axle side, for example.

However, according to the above structure, since the end surface 1C of the fiber bundle 1 of the core part 12 is cut diagonally, the fifth
(see figure), the tip is easily crushed when the end is pressed during the squeezing process, and it is also easier to extrude excess resin. Therefore, it is possible to avoid or reduce the occurrence of local areas with a high resin content, and at the same time, it is possible to reduce air bubbles, which is effective in preventing a decrease in strength.

Note that FIG. 3 shows another embodiment of the present invention.

In this case, the end surface 1c has a tapered shape such that the width at the tip side gradually becomes narrower toward the center in the width direction, and the end surface 1a has a rounded tip. In this case, the shape of the tip is symmetrical in the width direction, and the reinforcing fibers in the long portions only need to flow by half the width of the board, so they can more easily reach the end faces in the width direction than in the case of FIG. However, the tip does not necessarily have to be rounded. Other points are similar to the embodiment shown in FIG. M2.

〔Effect of the invention〕

According to the present invention, in an FRP tapered leaf spring in which a core portion and an outer layer portion are formed by reinforcing fiber bundles, it is possible to prevent localized areas with a high resin content from occurring and also to reduce air bubbles. Can prevent strength loss.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a leaf spring showing one embodiment of the present invention, and FIG.
The figures are a perspective view showing the end of the reinforcing fiber bundle used in the plate spring of Fig. 1, Fig. 3 is a perspective view showing another embodiment of the present invention, and Fig. 4
The figure is a side view schematically showing the arrangement of the reinforced II miscellaneous bundles. FIG. 5 is a perspective view showing the end of a conventional reinforced ms bundle, and FIG. 6 is a side view of the end of the reinforcing fiber bundle shown in FIG. 1... Reinforcing fiber bundle of core portion, Ia-... End surface, 2...
- Reinforcing fiber bundle of outer layer part, 10... FRP tapered leaf spring, 11... outer layer part, 12... core part. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A reinforcing fiber in the core portion, comprising an outer layer portion formed by impregnating a reinforcing fiber bundle with a resin, and a core portion formed by impregnating a reinforcing fiber bundle shorter than the outer layer portion with a resin and covered by the outer layer portion, and the reinforcing fiber of the core portion. An FRP tapered leaf spring characterized in that the end face of the bundle is not cut perpendicularly to the longitudinal direction of the leaf spring, but is cut diagonally or in a tapered shape such that the width on the tip side gradually becomes narrower.