JPS5952302B2 - FRP leaf spring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FRP leaf spring device having a plurality of spring plates.

In a conventional FRP leaf spring device, for example, as shown in Fig. 1, a main spring plate a made of FRP is stacked with an auxiliary spring plate also made of FRP, and these spring plates a and l) are used to prevent mutual wear. The structure is such that a center spacer C is sandwiched in between and fastened with a center bolt d.

The FRP leaf spring device having the above structure is used, for example, in an automobile body suspension system.

In this case, the eye parts e and e are fixed to the vehicle body side, and the center part of the spring plate is fixed to the axle side.

When a downward load is applied to the centerpieces e and e and the main spring plate a is deflected in the direction of the arrow shown in the figure, when the deflection exceeds a certain level, the main spring plate a moves to both ends b' and b' of the auxiliary spring plates.
The load of the main spring plate a is mainly supported by the two end portions b' and b'.

Therefore, the spring characteristics are shown by the imaginary line K in Figure 2. As shown in Figure 2, the load-deflection curve suddenly rises from the point of contact with the auxiliary spring plate, which has the disadvantage of deteriorating riding comfort.

Particularly in the case of FRP leaf spring devices, as mentioned above, a center spacer C is often interposed between each spring plate to prevent wear, and a gap is formed between the spring plates by the thickness of this center spacer C. Therefore, when the main spring plate a exceeds a certain amount of deflection, the main spring plate a suddenly comes into contact with both ends b' and b' of the auxiliary spring plate, thereby creating a smooth load-deflection curve. The problem was that it was difficult to obtain.

The present invention was made based on the above circumstances, and its purpose is to prevent wear even when using FRP main spring plates and auxiliary spring plates, and to ensure that the load-deflection curve continues smoothly. It is an object of the present invention to provide an FRP leaf spring device that can improve riding comfort especially when used for vehicle suspension.

That is, the present invention has a main spring plate made of FRP, an auxiliary spring plate made of FRP provided overlappingly on the tensile stress side of the main spring plate, and a main spring plate provided on the end of the auxiliary spring plate facing the tensile stress side. It comprises a support attached to the end of the spring plate, and an elastic member attached to at least one of the mutually opposing surfaces of the support or the auxiliary spring plate, and when the deflection of the main spring plate increases. In the FRP leaf spring device, the elastic member is compressed between the support body and the auxiliary spring plate, and the auxiliary spring plate gradually bends together with the main spring plate.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

In FIG. 3, 1 in the figure is a main spring plate made of FRP,
This main spring plate 1 has a shape that is curved upward in the drawing.

An auxiliary spring plate 2 made of FRP is superimposed on the upper surface side of the main spring plate 1, that is, on the side where tensile stress is generated.

This auxiliary spring plate 2 is slightly shorter than the main spring plate 1, and is formed in a shape that is slightly curved upward in the unloaded state.

The main spring plate 1 and the auxiliary spring plate 2 are fastened to each other by a center bolt 4 with a center spacer 3 for wear prevention interposed in the center in the longitudinal direction.

Further, metal eyeball members 5, 5 are provided at both ends of the main spring plate 10.
is attached by bolt 6.6.

Supports 7, 7 facing the tensile stress side of the end portions of the auxiliary spring plates 2 are formed integrally with each eyepiece member 5, 5.

An elastic member 8 made of an elastic material such as rubber or the like is provided on the surface of the supports 7, 7 facing the auxiliary spring plate.
8 is attached.

As shown in FIG. 4, the elastic members 8, 8 have nonlinear spring characteristics such that the load increases progressively as the amount of deformation increases when compressed, and the main spring plate 1 is spaced apart from the top surface of the end of the auxiliary spring plate 2 when it is under no load or under a light load.

When the FRP leaf spring device configured as described above is used in a vehicle body suspension system for an automobile, the center member 5.5 is attached to the vehicle body side, and the center bolt 4 vicinity is attached to the axle side.

When a downward load is applied to the eyeball members 5, 5 and the main spring plate 1 is bent downward, the elastic members 8, 8 are integrated with the main spring plate 1.
also moves downward.

Then, just before these elastic members 8, 8 contact the upper surface of the auxiliary spring plate 2, that is, the surface on the tensile stress side, the main spring plate 1
The load-deflection curve of the material becomes 1 (see Fig. 2), and flexible spring properties are obtained in the light load range.

As the load increases, the deflection of the main spring plate 1 increases, and when the elastic members 8, 8 come into contact with the auxiliary spring plate 2, the elastic members 8, 8 are compressed and a repulsive force is exerted.

Therefore, the spring characteristic is the spring constant of the main spring plate 1 plus the repulsive force of the elastic members 8, 8, and the greater the deflection of the main spring plate 1, the greater the influence of the elastic members 8.8.

That is, as shown by the curve 2 in FIG. 2, the load-deflection characteristic is smoothly continuous.

Then, the deflection of the main spring plate 1 further increases and the elastic members 8, 8
When the amount of compression increases and the repulsive force progressively increases, the auxiliary spring plate 2 is also bent integrally with the deflection of the main spring plate 1 and the compression of the elastic member 8.8, and the auxiliary spring plate 2 A spring constant of is added.

That is, the load-deflection characteristic in the large load region rises as shown by 3 on the solid line, and a spring characteristic that smoothly continues from K2 to 3 can be obtained.

As is clear from the above, according to the above FRP leaf spring device, it is possible to obtain nonlinear spring characteristics that smoothly continue as the load increases, and good riding comfort can be obtained regardless of the magnitude of the load. It is.

Even if the main spring plate 1 is bent, the main spring plate 1 will not come into contact with the auxiliary spring plate 2, so even if FRP spring plates 1 and 2 are used, there will be no problem of wear due to contact between the two. .

Therefore, it is highly effective in maintaining the durability of the FRP leaf spring device.2Although in the above embodiment, the elastic member 8°8 is separated from the auxiliary spring plate 2 in the light load range, the present invention is not limited to this. For example, when there is no load or a light load, the elastic member 8,
8 may be in contact with the auxiliary spring plate 2, and the elastic members 8, 8 may be made of a synthetic resin foam having a relatively large elastic deformability, such as urethane foam.

According to such a structure, since the elastic members 8, 8 are already in contact with the auxiliary spring plate 2 when there is no load or a light load,
When the deflection of the main spring plate 1 increases, the repulsive force of the elastic members 8, 8 is gradually added, and the auxiliary spring plate 2 is gradually deflected.

Therefore, the load-deflection characteristics can be made to continue more smoothly.

Further, in the present invention, a double-structured elastic member 8 as shown in FIG. 5 may be used.

That is, this elastic member 8 includes a rubber having a higher elastic modulus (higher spring constant) than the first elastic body 8a, inside a first elastic body 8a made of synthetic resin foam or the like and having a relatively small elastic modulus. The second elastic body 8b is housed therein.

Therefore, according to this embodiment, while the amount of deflection of the main spring plate 1 is small, the first elastic body 8a is mainly compressed and its repulsive force is added to the spring constant of the main spring plate 1, so that the load - The deflection curve is a relatively gentle and smoothly rising curve.

Then, when the deflection of the main spring plate 1 increases and the internal hard second elastic body 8b begins to be compressed, the load-deflection curve begins to rise significantly from this point on due to the repulsive force of the second elastic body 8b. Nonlinear spring characteristics can be obtained.

In each of the above embodiments, the elastic members 8, 8 may be provided on the auxiliary spring plate 2 side.

Further, the number of spring plates may be three or more, and it is of course applicable to a cantilever type plate spring device.

In addition, in the above embodiment, the support body 7 is formed integrally with the centerpiece member 5 to simplify the structure and facilitate the installation work, but it is not necessarily necessary to form the support body 7 integrally with the eye member 5. The body may be constructed separately from the eyepiece member and attached separately using bolts or the like, or they may be aligned using a common bolt.

Further, as shown in FIG. 6, a smoothly continuous support body 7 may be adopted, or as shown in FIG. The attachment strength of the eyepiece member 5 may be strengthened by providing the eyepiece member 5.

As explained above, the present invention interposes an elastic member between the auxiliary spring plate and the support provided to face the surface on the tensile stress side of the auxiliary spring plate, so that when the deflection of the main spring plate increases, the The elastic member is compressed between the support body and the auxiliary spring plate, and the auxiliary spring plate gradually bends together with the main spring plate.

Therefore, according to the present invention, even if the main spring plate is bent due to an increase in load, the main spring plate does not come into contact with the auxiliary spring plate.
Therefore, even if the main spring plate made of FRP and the auxiliary spring plate made of FRP are used, no problem of wear occurs.

However, it is possible to prevent problems such as the sudden rise in the load-deflection curve from the moment the main spring plate contacts the auxiliary spring plate, which occurs when a center spacer is used to prevent wear in the past. , a smoothly continuous load-deflection curve is obtained.

Therefore, when used in a vehicle suspension system, for example, a good ride comfort can be obtained regardless of the magnitude of the load.

However, as mentioned above, there is no problem with wear, and it is extremely effective in maintaining the durability of FRP spring plates.
Great effects can be achieved in the FRP leaf spring device.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a conventional FRP leaf spring device, Fig. 2 is a load-deflection characteristic diagram, Fig. 3 is a front view showing an embodiment of the present invention, and Fig. 4 is a spring characteristic diagram of an elastic member. , FIG. 5, FIG. 6, and FIG. 7 are front views of a portion of a leaf spring device showing other embodiments of the present invention. 1...Main spring plate, 2...Auxiliary spring plate,
3... Curved center spacer, 4... Center bolt, 5... Eyepiece member, 7... Support body, 8... Elastic member.

Claims (1)

[Claims] I A main spring plate made of FRP, an auxiliary spring plate made of FRP placed over the tensile stress side of this main spring plate, and an end of the main spring plate opposite to the tensile stress side of the end of this auxiliary spring plate. 1. An FRP leaf spring device comprising: a support body attached to a portion thereof; and an elastic member attached to at least one of the mutually opposing surfaces of the support body or the auxiliary spring plate.