JPS6319738B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tightening structure for FRP spring plates.

2. Description of the Related Art A leaf spring device used in a suspension system for an automobile or the like is provided with a tightening means for tightening the vicinity of a longitudinally central portion of a band-shaped spring plate in the thickness direction. If the above spring plate is made of FRP, the FRP spring plate tends to be elastically deformed, so the tightening by the above tightening means tends to be uneven, and it is difficult to achieve sufficiently high dimensional accuracy, and it is anisotropic. (the reinforcing fibers are buried mainly along the longitudinal direction of the spring plate), the stress distribution in the area where the tightening load applied by the tightening means, ie, the tightened portion, tends to become complicated. Therefore, there are drawbacks such as a tendency for cracks to occur in the longitudinal direction and a decrease in strength around the center hole where stress concentration is likely to occur.

The present invention has been made under the above circumstances, and its purpose is to make it possible to regularize the stress distribution in the tightened part even if ordinary FRP spring plates and tightening means are used. Therefore, it is an object of the present invention to provide a fastening structure for an FRP spring plate that can improve the durability of the spring plate.

Hereinafter, the present invention will be described with reference to illustrated embodiments. In FIGS. 1 and 2, a vehicle suspension leaf spring device A has a single or plural band-like shape (the figure shows three springs).
FRP spring plates 1, 2, and 3 are provided. These spring plates 1, 2, and 3 each have a center bolt 5 that passes through a bolt hole 4 formed in the center of each spring plate.
It is positioned by a nut 6 which is screwed into this. Further, the tightening means 7 includes the spring plates 1, 2,
3, a pair of U bolts 10 that support the lower member 9 from below and pass through the upper member 8,
It has a nut 11 screwed onto a bolt 10, and is configured to tighten the spring plates 1, 2, and 3 in the thickness direction. The above general configuration may be the same as that of the conventional device.

In the present invention, spacers 12 are provided on both sides of the spring plates 1, 2, and 3 in the thickness direction, and are located only in the vicinity of the edges of the areas tightened by the tightening means 7. That is, the spacer 12... is
Between the upper member 8 and the first spring plate 1, the spring plate 1,
2 and 3, and between the No. 3 spring plate 3 and the lower member 9, and extend only along the edges of these mutually opposing parts. These spacers 12 are made of flexible material, such as suitable FRP.
It is preferable that the corner portion 13 is chamfered with an appropriate curvature on the side that comes into contact with the spring plates 1, 2, 3, etc., as illustrated in FIG. Further, the spacer 12 may be formed in a rectangular annular shape as illustrated in FIG. 4, or may be formed in an oval annular shape, an elliptical annular shape, or the like. If necessary, as illustrated in FIG. 5, spacers 12a spaced apart in the width direction of the spring plate and spacers 12b spaced apart in the longitudinal direction are provided separately on both sides in the thickness direction. In some cases, these spacers 12
Either one of a and 12b may be omitted and, for example, they may be arranged only on both side edges in the width direction.

According to the above configuration, each spring plate 1, 2, 3 is tightened in the thickness direction via the spacer 12, so that
The clamping load of the clamping means 7 acts via the edges of its clamping area. Therefore, spring plates 1, 2, 3
Even if the dimensional accuracy of the spring plate is not high, the stress distribution will be regular and there will be no local stress concentration, and especially no bending moment that could cause longitudinal cracks in the spring plate. do not have. As a result, the durability of each spring plate 1, 2, 3 can be improved.

As described above, the present invention provides spacers on both sides in the thickness direction of the band-shaped FRP spring plate, located only in the vicinity of the edge of the area to be tightened by the tightening means. Even if the attachment means is used, the stress distribution becomes regular and no harmful stress concentration occurs, so that the durability can be improved.

[Brief explanation of the drawing]

Figure 1 is a side view showing one embodiment of the present invention, Figure 2 is a side view showing one embodiment of the present invention;
The figure is an enlarged sectional view taken along the - line in Figure 1, Figure 3 is an explanatory diagram showing an enlarged view of the main part, Figure 4 is a perspective view of the main part, and Figure 5 is an explanation showing a modification of the main part. It is a diagram. 1, 2, 3...FRP spring plate, 7...tightening means,
12, 12a, 12b...spacer.

Claims (1)

[Claims] 1. In a device having a tightening means for clamping and tightening a band-shaped FRP spring plate in the thickness direction, the tightening means is located on both sides of the spring plate in the thickness direction only near the edge of the tightening area by the tightening means. A fastening structure for FRP spring plates characterized by the provision of spacers.