JPS60136631A - Frp springboard system - Google Patents

Abstract

PURPOSE:To make practicable by contacting a coil spring against an eye member fixing section of master springboard having low bending stress thereby preventing abrasion, damage, etc. of FRP master springboard. CONSTITUTION:Eye members 2, 2 are fixed at the opposite ends of FRP master springboard 1. FRP slave springboard 6 is laminated over the master springboard 1 where both springboards 1, 6 are restricted at the intermediate section in longitudinal direction by means of a center bolt 7. Coil springs 10, 10 are fixed to the end of slave springboard 6 such that they will contact against the fixing section of eye members 2, 2 where the stress is lowest. Metal stopper boards 3, 3 are provided at the contacting section of master springboard 1 and coil springs 10, 10 as the spring receiving section.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FRP leaf spring device used in vehicle suspension mechanisms and the like.

Recently, in order to reduce the weight of vehicles, there is a tendency to use FRP spring plates in suspension mechanisms. The disadvantage of FRP is that it is susceptible to wear and impact. Therefore, in the case of a multi-leaf spring with non-linear characteristics in which the spring constant increases as the load increases, where multiple spring plates repeatedly come into contact and non-contact, the spring plates should be When made of FRP, mutual contact parts are likely to wear out and be damaged.

On the other hand, in a known stacked leaf spring device using steel spring plates, for example, as seen in Japanese Patent No. 114853, a coil spring is interposed between upper and lower spring plates having different lengths, and the main spring plate is There is also a device in which the spring constant is gradually increased by transmitting the force to the child spring plate through the coil spring. However, in this known example, since the coil spring is in contact with the middle part of the eye of the main spring plate and the center clamp part, there is no problem with the steel spring plate, but with the FRP spring plate. In this case, it has become clear through research by the present inventors that there is a risk that the main spring plate will be worn out and damaged at the portion where the coil spring comes into contact with it.

The present invention has been developed based on the above circumstances, and its purpose is to develop an FRP that can obtain progressive type characteristics without causing wear, damage, etc. as described above.
An object of the present invention is to provide a leaf spring device.

The present invention focuses on the eyeball attachment portion where the bending stress of the parent spring plate is the lowest, and the coil spring is brought into contact with this eyeball attachment portion.

The gist of the present invention is to provide an FRP leaf spring device having a master spring plate made of FRP with a center member attached to the end, and slave spring plates stacked in the thickness direction of the master spring plate. A coil spring is attached to the end of the spring plate at a position facing the center member attachment portion of the main spring plate.

An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 indicates a main spring plate made of FRP, and eye members 2, 2 made of metal or FRP are attached to both ends of this main spring plate 1. Each eyeball member 2, 2
are fixed to the end portions of the main spring plate 1 using metal backing plates 3, bolts 4, and nuts 5, respectively.

Each of the eyeball members 2, 2 is supported on the vehicle body side of a vehicle (not shown). The abutting plate 3 also serves as a metal spring receiving portion for receiving a coil spring 1o, which will be described later.

Further, a child spring plate 6 made of the same (FRP) is provided overlappingly in the thickness direction of the main spring plate 1. This child spring plate 6 has approximately the same length as the main spring plate 1. In addition, in order to further reduce the weight, both spring plates 1 and 6 are designed as tapered leaves in which the plate thickness gradually decreases on the edge side of each plate to equalize the stress at each part in the longitudinal direction of the legs. In some cases, the child spring plate 6 may be made of steel.

Further, both spring plates 1 and 6 are restrained at their mutually intermediate portions in the longitudinal direction by a center port 7, and an axle housing (not shown) is attached to this portion.

Coil springs 10 and 10 are attached to both ends of the child spring plate 6.
is installed. Since these coil springs 10.10 have the same structure, one will be described below as a representative.

In this embodiment, the coil spring 1θ is composed of a coil spring main body 11 and a spring seat 12 fixed to the coil spring main body 1).

As illustrated in FIG. 2, a spring seat 15 is fixed to the end of the child spring plate 6 using a nut 13 and a washer 14, and the coil spring Io is fixed 17 to this spring seat 15. Therefore, the coil spring 10 is provided at a position on the master spring plate 1 facing the attachment portion of the eyepiece member 2, and at a position facing the lower surface side of the metal backing plate 3 in this embodiment. Note that the spring seats 12.15 are formed of metal, FRP, or a single synthetic resin.

The leaf spring device of this embodiment having the above-mentioned configuration has center members 2 at both ends.
When a downward load is applied to 2 due to a vehicle body load, only the main spring plate 1 grinds while the load is small.

When the load increases and the deflection of the master spring plate 1 becomes large, the lower surfaces of the backing plates 3, 3 begin to come into contact with the spring seats 12, 12.

However, both spring seats 12, 12 do not necessarily come into contact at the same time.

When the load increases, the coil springs 10, 10 are baked in accordance with the magnitude of the load, and the reaction force is transmitted to the main spring plate 1 via the backing plates 3, 3. In addition, a force that causes the child spring plate 6 to bend downward is also applied.

Therefore, when at least one of the coil springs 10, 10 starts contacting, the spring constant increases, and the coil springs 10, 10
When the springs are completely in contact with each other, the spring constant becomes substantially the maximum. After that, the child spring plate 6 and the master spring plate 1 are deflected in the same way, resulting in a substantially constant load-deflection characteristic. Therefore, the above leaf spring device can function as a flexible spring in a light load range and as a stiff spring in a large load range.
Progressive type characteristics are obtained, and good results are obtained in terms of improved handling stability and riding comfort. In addition, spring plates 1 and 6
Of course, by using FRP, it is possible to achieve a significant weight reduction compared to conventional steel springs.

According to the above embodiment device, the coil spring 10.10
is the centerpiece member 2, which is the lowest stress point of the main spring plate 1;
2, and this contact portion is provided with metal backing plates 3, 3 as spring receivers. Therefore, there is less damage due to wear or impact, and FRP411
! This is extremely effective in protecting the main spring plate 1 from breakage accidents.

Furthermore, when the coil spring 1O is made of FRP, it is possible to further reduce the weight. Further, if an elastic body such as rubber or synthetic resin is used for the spring seat 12, it is effective to reduce the tapping noise.

In addition, as illustrated in FIG. 3, a conical coil spring may be used as the coil spring 1θ, and the spring wire may be made into a tapered wire such that the thickness of the spring wire becomes thinner on the small diameter portion 10h side. By doing this, the contact height of the coil spring 1θ can be made lower than that of a normal coil spring (see FIG. 2), and a sufficient amount of tension can be ensured. For the same purpose,
A barrel-shaped coil spring or a spring-shaped coil spring can also be used.

Furthermore, as shown in FIG. 4, the surface 12m of the spring seat 12 facing the master spring plate 1 may be sloped so that the backing plate 3 can evenly contact the facing surface 12a.

Alternatively, as shown in FIG. 5, the coil spring 10 may be mounted on a spring seat 15 that is inclined so that its axis is perpendicular to the opposing metal spring holder (backing plate 3, etc.). You can also do this. In this case, coil spring 1o
The direction of the load applied to the coil can be made to substantially match the axis of the coil.

Further, as illustrated in FIG. 6, a rubber-like elastic body 2o may be interposed between the spring seats 12 and 15 so that the coil spring wires do not come into contact with each other even under the maximum load. in this case,
It is possible to prevent the occurrence of tapping noise, and also to prevent a decrease in fatigue strength due to impactful contact. The elastic body 2O is fixed to either one of the spring seats 12 and 15.

Further, the eyeball member 2 illustrated in FIG. 7 includes an eyeball main body 2 made of FRP, and a bushing 22 made of metal or the like held on this eyeball main body 21. In this case, in order to prevent the eyeball body 21 made of FRP from coming into direct contact with the coil spring 10, the metal plate 3 is fastened together with the eyeball body 21 using a bolt 4 and a nut 5.

In each of the above embodiments, the metal backing plate 3 is used as the spring receiving part.
However, in the case of a metal eyepiece member, for example, a part of the eyepiece member may be opposed to the coil spring 10, and the coil spring 10 may be brought into contact with this portion. In this case, a part of the metal eyepiece member also serves as a spring receiver.

In addition, as schematically shown in Figure 8, sudden start of the vehicle,
In order to cope with the wind-up phenomenon that sometimes occurs during sudden braking, the spring constants of the coil springs 1o and 1° may be made to be different from each other. In this case, the windup characteristics can be improved by increasing the spring constant or free height of the side that receives larger deflection during windup.

Furthermore, the present invention can of course be applied to a stacked leaf spring device having two or more child spring plates.

Furthermore, if a metal spring receiving part (such as the backing plate 3) is not used, the spring seat 12 may be made of a rubber-like elastic body or the like.

As described above, according to the present invention, since the coil spring is brought into contact with the center member attachment part of the main spring plate with low bending stress, there is no problem with wear, damage, etc. when the main spring plate is made of FRP. It is possible to prevent defects in p, FRP
It is possible to realize the practical use of a progressive type FRP leaf spring device by combining a spring plate and a fill spring.

[Brief explanation of drawings]

FIG. 1 is a front view of an FRP plate spring device showing one embodiment of the present invention, FIGS. 2 to 6 are cross-sectional views showing mutually different aspects of the coil spring portion, and FIG. 7 is one of the centerpiece members. FIG. 8 is a cross-sectional view showing a modification, and a front view schematically showing a wind-up state. 1... Main spring plate, 2... Eye member, 6... Child spring plate, 10... Coil spring. Applicant's Representative Patent Attorney Takehiko Suzue Figure 2 Figure 3 Figure 6 Figure 8

Claims (4)

[Claims] (1) In an FRP leaf spring device having a master spring plate made of FRP with a centerpiece attached to the end and a slave spring plate stacked in the thickness direction of the master spring plate, the end of the slave spring plate is teeth,
An FRP leaf spring device characterized in that a coil spring is attached to a position facing the center member attachment portion of the main spring plate. (2) The FRP leaf spring device according to claim (1), wherein the parent spring plate is provided with a metal spring receiving portion on a surface with which the coil spring comes into contact. (3) The FR according to claim (1), characterized in that a conical coil spring is used as the coil spring.
P leaf spring device. (4) The FRP board according to claim (1), wherein the coil spring is installed with an inclination so that the axis of the coil is oriented substantially perpendicularly to the eyepiece attachment part. Spring device.