JPS5836217B2 - Layered leaf spring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved stacked leaf spring device having high plate-to-plate frictional resistance and non-linear spring characteristics.

In stacked leaf spring devices used in automobile suspension systems, it is always desired to have good riding comfort and steering stability regardless of the magnitude of the load, and to achieve this, it is necessary to make the spring characteristics nonlinear and increase the frictional force between the plates. There are measures such as:

However, conventional means of this type generally have drawbacks such as a complicated structure and an increase in weight, and many of them are not suitable for practical use.

The present invention has been made under the above circumstances, and its objectives are to have a simple structure, to be able to manufacture it at low cost, to easily obtain large interplate friction force and nonlinear spring characteristics, and to Therefore, it is an object of the present invention to provide a stacked leaf spring device which does not increase in weight and is particularly suitable for suspension systems for automobiles.

Hereinafter, the present invention will be described with reference to an illustrated embodiment.

In Fig. 1, a plurality of spring plates 1, 2 (in the case of three in the figure)
．． 3 is made of, for example, a spring steel material, and is polymerized in the thickness direction.

In the illustrated example, each of the spring plates 1, 2, and 3 is formed into a tapered shape that is thick in the center and thin at both ends, but the rate of variation in thickness in the longitudinal direction may be linear or nonlinear. , or the thickness may be constant.

Each spring plate 1, 2.3 is tightened in the thickness direction by a center bolt 4 inserted into a through hole formed in the center in the longitudinal direction and a nut 5 screwed into the center bolt 4.
A liner 6 having a predetermined thickness is interposed between the second spring plate 2 and the third spring plate 3.

The first spring plate 1 has eye-shaped portions 7 on both ends,
It has 7.

The second spring plate 2 has curved portions 8 formed at both ends,
It is equipped with 8.

This curved portion 8 has a substantially arc shape, for example, a substantially semicircular shape, and is curved in a direction opposite to and surrounding the third plate end 3a.

Further, the third spring plate 3 has plate end portions 3a, 3a close to the second spring plate.

When a load exceeding a predetermined value is applied downward in the figure through the eyeball part 7, the plate end 3a gradually slides toward the back of the curved part 8 as the deflection of the spring plate increases. Both plate ends 3a and 3b are slidably stacked on top of each other so that the surface pressure increases.

The stacked leaf spring device configured as described above is attached to, for example, an automobile suspension system by means (not shown) substantially similar to those used in conventional devices.

In the device configured as described above, when the first spring plate 1 is bent due to a downward load applied through the centerpiece 7, the second spring plate 2 bends as shown in FIG.
is also curved in the same direction.

As the load increases, the second spring plate 2 moves to the third spring plate.
The second spring plate 2 comes into contact with the plate end 3a of the second spring plate 3, and as the load further increases, the two slide against each other, but since the second spring plate 2 is provided with the curved part 8, the load is In the area exceeding the predetermined value, the plate end 3a and the curved portion 8
come into sliding contact with each other.

In this state, the plate end 3a is connected to the second spring plate 2.
As the third spring plate 3 becomes locally curved due to relative displacement in the longitudinal direction, the third spring plate 3 receives a larger bending force than in the case where no curved part is provided. , the surface pressure on both sliding parts also increases.

That is, compared to the conventional device that does not have the curved portion 8, the third
The second spring plate 3 generates a larger reaction force against the bending force and friction between the plates, and the reaction force and the friction between the plates increase as the load increases.

Therefore, in order to obtain the same deflection as a leaf spring device due to the increased reaction force, a larger load is required than in the conventional device, so the deflection (δ) load (w) characteristics, that is, the spring characteristics, are shown in Figure 3. As shown by solid line A, it becomes nonlinear.

Note that the dotted line B in FIG. 3 is the spring characteristic of the conventional device shown for comparison.

Furthermore, as described above, since the plate end 3a comes into sliding contact with the curved portion 8, a large frictional force is generated between the second and third spring plates, and this frictional force increases as the load increases.

That is, as the deflection of the spring plate increases, the plate end 3a
This plate end 3 slides into contact with the inner surface of the curved portion 8, that is, the part where the slope relative to the plate end 3a rapidly increases.
The interplate friction force at a increases progressively and continuously.

Therefore, the effect of increasing the frictional force between the plates is very large.

As the friction between the plates increases, the amount of work due to friction when the deflection returns increases, that is, the energy consumption when unloading increases, so the damping effect can be increased.

Further, the nonlinear effect of the spring characteristics and the effect of increasing the interplate friction force as described above are enhanced as the thickness of the liner 6 increases.

Tables 1 and 2 compare the characteristics of the present invention (Category A) and the conventional device (Category B).

Each of these consists of three spring plates each having a width of 70 mrrL and a thickness of 14 mm, and the distance between the centers of the eyepieces is 1200 mm.

Note that the interplate friction force shown in Table 2 is expressed as the difference between the load W when the load increases and the load V when the load decreases for a predetermined deflection.

In the table, Category C is a type in which the number of spring plates is increased in order to obtain a friction force between the plates almost equivalent to that of the present invention, and is composed of five spring plates with a thickness of 11 mm.

In addition, in order to obtain nonlinear spring characteristics almost equivalent to those of the present invention, in category D, two spring plates with a thickness of 11 mm and a spring plate with a thickness of 12 mm are used.
This is a case of a known progressive type stacked leaf spring device which is composed of one spring plate of RRT and one spring plate of 18 mm in thickness.

As can be seen from Tables 1 and 2 above, although the weight and number of spring plates of the present invention are almost the same as those of the conventional device of Category B, it has non-linear spring characteristics and the frictional force between the plates is reduced. It has approximately doubled.

In addition, when compared with the type C, which has approximately the same frictional force between the plates, it has a weight of about 85% and has nonlinear spring characteristics, and when compared with the type D, which has approximately the same spring characteristics, The weight is approximately 82.5%.

That is, the present invention has better characteristics than any of the various conventional devices mentioned above.

As mentioned above, it has nonlinear spring characteristics and a large friction force between the plates, and is also lightweight, so it is particularly suitable for automobile suspension systems, and can greatly improve riding comfort under light load conditions. It is possible to obtain vibration damping properties and desired roll rigidity.

Moreover, since the curved portions 8 are simply formed by bending the end portions of some of the spring plates, the structure is simple and can be manufactured at low cost.

Note that the present invention is not limited to the above embodiments.

For example, the shape, number, arrangement, etc. of each spring plate can be set as appropriate, and as illustrated in FIG. Alternatively, curved portions 8, 8 may be formed at both ends of the third spring plate 130 so as to surround the end portions of the fourth spring plate.

In addition, as illustrated in FIG. B, the fourth spring plate 14
Both sides in the longitudinal direction are inclined downward and curved parts 8, 8 are formed at both ends thereof, and the fifth spring plate 15
You may also make it almost flat.

Furthermore, as illustrated in FIG.
The eyelet portion 7 may be formed only at one end of the second spring plate 12, or the curved portion 8 may be provided only at one end of the second spring plate 12, for example.

Further, the curved portions may be provided on each of the plurality of spring plates, and various other changes and applications are possible within the scope of the gist of the present invention.

As described above, a pair of spring plates whose plate ends face each other are fastened to each other with a liner interposed between them, and one of these spring plates is provided with a pair of spring plates facing the plate end of the other spring plate. A curved portion is provided in the direction surrounding the plate end, and when a load exceeding a predetermined value is applied, the plate end of the other spring plate bends as the deflection of the spring plate increases. It is characterized in that it gradually slides into contact with the inner side of the curved portion.

Therefore, it is possible to easily obtain a large interplate friction force that increases continuously and progressively as the load increases, and nonlinear spring characteristics.

In addition, as the friction between the plates increases, the amount of work due to friction when the deflection returns increases, and the damping effect when unloading can be increased, so even if the number of spring plates is small, the so-called fluffy feeling is eliminated and the steering becomes stable. It can improve performance and ride comfort.

Furthermore, it is possible to provide a stacked leaf spring device which has a simple structure, can be manufactured at low cost, does not involve an increase in weight, and is particularly suitable for suspension systems for automobiles.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the same example, FIG. 3 is a diagram for explaining the spring characteristics of the same example, and FIGS. 4A, B, C is an explanatory diagram showing mutually different modifications of the present invention. 1-3, 11-15...Spring plate, 3a...
... Plate end, 4 ... Center bolt, 5 ...
...Nut, 8...Curved part.

Claims (1)

[Claims] 1. In a stacked leaf spring device having a plurality of spring plates which are overlapped in the thickness direction and whose intermediate parts in the longitudinal direction are fastened to each other, a pair of spring plates whose end parts face each other are held together in the longitudinal direction. A lychee is sandwiched in the middle part and they are fastened to each other, and the end of one spring board is curved in a substantially arc shape in a direction that opposes and surrounds the end of the other spring board. A curved portion is provided, and when a load exceeding a predetermined value is applied, as the deflection of the spring plate increases, the plate end of the other spring plate gradually slides toward the inner surface of the curved portion. A stacked plate spring device characterized in that both plate ends are slidably stacked on each other so that surface pressure increases.