JPH0357710A - Suspension arm structure made of frp - Google Patents

Abstract

PURPOSE:To prevent a suspension arm structure from the degradation of strength due to repeated deformation by disposing higher strength fibers in a high tensile stress generating position under a large compression load of an arm part, compared with fibers in the other positions. CONSTITUTION:A first reinforcing fiber layer 16a formed of carbon system long fiber filament windings or the like is formed to be arranged in parallel longitudinally of flange members 14, 14 of an arm part 11, i.e. in the longitudinal direction coinciding with the operative direction of a compression load. Further, a second reinforcing fiber layer having higher strength than the first reinforcing fiber layer 16a is formed of similar filament windings on the outer periphery of flange members 14, 14 in the bending direction, i.e. on the opposite side to parts forming notches 15, 15. This second reinforcing fiber layer 16b is formed of a composite body consisting of combination of glass fibers and carbon fibers or the like. Thus, the strength degradation due to repeated deformation can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a suspension arm structure made of FRP.

(Prior Art) For example, as shown in Japanese Unexamined Patent Publication No. 56-101415, recently, from the viewpoint of reducing the weight of the vehicle body and improving ride comfort, the suspension arms of automobiles are fabricated by filament winding reinforcing fibers such as carbon fibers. They are manufactured from reinforced synthetic resin or shaped products.

As is clear from the description in the above-mentioned publication, such FRP suspension arms generally have a structure in which the reinforcing fibers are arranged in parallel in the longitudinal direction of the arm in order to increase the compressive load of the arm. It is taken.

In the case of a configuration in which the reinforcing fibers are arranged in parallel in the longitudinal direction of the arm portion in this way, when a uniform compressive load is applied to the entire arm section (from the ends to the axial direction), it certainly exhibits high compressive strength.

For example, FRP with a conventional structure as shown in FIGS. 10 and 11! ! Taking the suspension arm structure as an example, the distribution of the compressive load that actually acts on it is analyzed as follows.

That is, first, as shown in the figure, the structure of the suspension arm 10 is usually composed of the above-mentioned arm part 1 and the arm part 1.
It is formed by integrating ring portions 2a and 2b formed at both ends for coupling with the vehicle body side or suspension side. The ring parts 2a, 2b are generally formed of a steel cylinder, and the cylinder has an I-shaped cross section, for example, to increase the bending rigidity of the concave end parts 1a, ib of the arm part 1. The reinforcing fiber layer 3 as shown in the figure is formed by bonding the fibers to each other and then endlessly winding filaments around their outer peripheries.

Although not particularly shown, the central member 4 of the arm portion 1
Reinforcing fibers are also arranged in parallel in the longitudinal direction on both sides as shown by broken lines.

Then, each of the coupling ring portions 2 a, 2 bl.
:t, for example, as shown in FIG. 11, the shaft member 7 of the bracket (not shown) is attached to the mating (vehicle body or suspension) side via elastically deformable rubber pushers 5a, 5b.
It is designed to be fitted and coupled to a7b.

Therefore, first, from the shaft members 7a and 7b side, the rubber bushings. ．． The compressive load Fp applied to the arm portion 1 via L5a, 5b and the ring portions 2a, 2b acts as shown by arrows in FIG. 10 at the joint portion of the arm portion 1 with the ring portion cylindrical body.

On the other hand, the tensile load acts in just the opposite direction.

The loads in both directions are determined by the above-mentioned F R l) suspended/yellow arm according to the permissible limit value according to the compression/tensile load strength specified by the rigidity of the material itself of the arm part l and its cross-sectional area. It is supported with a predetermined spring constant.

(Problem to be Solved by the Invention) Generally speaking, the vehicle body side mounting portion and the suspension side mounting portion, which are connected via the suspension arm, are offset by a predetermined amount (by an offset angle O). Normal. Therefore, at present, the above-mentioned suspension arm has no choice but to be bent to some extent, as shown in FIG. 3, for example, in order to absorb the offset.

However, if this is done, deformation due to bending moment is likely to occur, for example, as shown by the false line in the figure, and when a large load Fp of a predetermined value or more is applied in the compression direction, considerable deformation will occur.

When such deformation occurs, tensile stress in the directions of arrows (a) and (b) is generated on the right side (outside in the deformation direction) of the arm portion in the figure, and there is a risk that the reinforcing fiber layer 3 described above may be broken. On the other hand, on the left side (inward in the direction of deformation), compressive stress in the directions of arrows (C) and (2) is generated.

As a result, if the above deformation is repeated frequently,
There is a problem in that the inherent energy absorption ability of the suspension arm itself is reduced, resulting in poor riding comfort and reduced durability.

Furthermore, this situation is the same when the arm part of the suspension arm mentioned above can be configured straight without offsetting, but when the axis is asymmetrical, and if a large compressive load exceeding a certain value is applied, the FRP suspension will eventually become damaged. Since the scissor arm absorbs the load by bending in a specific direction, repeated deformation may lead to a decrease in strength.

(Means for Solving the Problems) The present invention aims to solve the above problems, and has coupling parts for coupling to the vehicle body and suspension at both ends of the arm part, respectively, and F installed between the vehicle body and the suspension via the
The R P 12 suspension arm is characterized in that fibers with higher strength than other parts are provided in the arm part where high tensile stress is generated under large compressive loads.

(Function) In the structure of the FRP suspension arm of the present invention, fibers having higher strength than other parts are arranged in the high tensile stress generation part of the arm part as described above, In particular, the reinforcement strength against tensile stress is set high.

Therefore, it is possible to maintain sufficient strength even if a structure is adopted in which the front and rear connection positions are offset, as is the case with conventional structures, where the peak moment during compression is likely to act. There is no chance of the fibers breaking or sliding. As a result, it becomes possible to effectively absorb load energy through stable elastic deformation.

(Effect of the invention) Therefore, according to the structure of the FRP suspension arm of the present invention, it has sufficient strength even against large compressive loads and can maintain stable ability to absorb mechanical energy such as impact energy. Highly reliable FRP! It becomes possible to use two suspension arms together.

(Example) Figures 2 and 2 show F according to the first embodiment of the present invention.
The structure of the RPi4 suspension arm is shown.

In the figure, reference numeral 10 is a suspension arm of the FRPI in this embodiment, and the suspension arm 10 includes an arm portion 1l and ring portions 12a and 12 provided at both ends of the arm portion 11 for coupling the vehicle body and suspension.
It is composed of b.

The arm portion 11 has both end portions 11a and llb having a predetermined thickness and concave end surfaces, and is connected to the ring portion 12a, llb.
A main body member 13 that abuts and is integrally joined to the outer peripheral surface of 12b.
and reinforcing flange members 14 and 14 joined to both sides of the main body member 13 in a T-shape, respectively, forming an I-shaped structure in cross section. Each of the above flange members 14.14
Both end portions extend tangentially to the circumferential surfaces of the ring portions 12a, 12b and are integrally joined.

The ring portions 12a and 12b are each formed into a metal cylinder, and predetermined rubber bushes L22a and 22b are interposed in the cylinder to attach the bracket to the vehicle body side and the suspension side (not shown). Each coupling shaft 23a on the bracket side. It is designed to be assembled by penetrating 23b.

By the way, in the case of this embodiment, the above seven lunge members 14.1
As shown in the figure, one side of 4 is cut out over a predetermined length in the front-rear direction, and the cutout portion 15.15 facilitates bending in the direction of arrow R, thereby providing a predetermined spring constant against compressive load. It is becoming a reality.

On the other hand, reference numeral 16a designates a first reinforcing fiber layer formed over the entire circumference of the arm portion 1l and ring portions 12a, 12b by, for example, filament winding of carbon-based long fibers. The first reinforcing fiber layer 16a is the flange member 1 of the arm portion 1l.4. 1 4 long plane direction,
In other words, the first reinforcing fiber layer 16a is arranged in parallel in the longitudinal direction in accordance with the acting direction of the compressive load Fp, and exhibits high strength against the compressive load Fp.
Since it is wound around the entire suspension arm 10 including the ring parts 12a and 12b, it exhibits high strength against the tensile load acting on the ring parts 12a and 12b. .

Furthermore, the reference numeral 16b is a reinforcing fiber layer 16a having higher strength than the first reinforcing fiber layer 16a, which is also formed by filament winding on the outer circumferential side in the bending direction of the flange members l4, 14 (on the side opposite to the cutout portions 15, 15-shaped round part). This is the second reinforcing fiber layer. The second reinforcing fiber layer 16b is formed when the arm portion 11 receives a large compressive load Fp of a predetermined level or higher,
1Δ1 For example, even in the case of large elastic deformation as shown by the virtual line in FIG. 3, sufficient tensile strength is ensured on the outer surface of the curved part to prevent the reinforcing fiber layer tea from breaking as in the conventional case. It is working.

For the second reinforcing fiber layer 16b, a combination of glass fiber and carbon fiber, glass fiber and aramid fiber, etc. is used, for example. The shape or method of the second reinforcing fiber layer 16b may be, for example, the side surface 14b of the flange member 14.14.
, 14b, and then add carbon wt fibers or aramid fibers, or form a part (predetermined width) of the side surface from the beginning into a high-strength cross-section with a composite of them. It may be formed by any of the following methods.

In this way, if a configuration is adopted in which the outer circumferential surface side (stretching side) of the arm portion 11 in the bending direction is reinforced with the second reinforcing fiber layer 16b, which has a particularly higher tensile strength than the inner side (shrinking side), it will not be able to withstand normal compressive loads. Against J. On the one hand, it achieves a stable impact energy absorption function through bending deformation that exhibits a high elasticity coefficient, and on the other hand, as shown in Figure 3, even when a particularly large compressive load is applied, the reinforcing fiber layer does not break and maintains stable elasticity. It begins to function as a suspension/yong arm with deformation.

Therefore, the ride comfort of the vehicle is also improved.

Moreover, the tensile load strength is also improved accordingly.

In this case, the first reinforcing fiber layer 16a
It is also conceivable to increase the strength of the fiber by increasing the number of turns to the level of adding the second reinforcing fiber layer 16b.

However, if such a method is adopted, a large number of turns will be required for unnecessary parts, leading to waste of material costs, molding time, etc., as well as an unnecessary increase in weight, making it difficult to reduce weight. Go against the request. Furthermore, since the cross-sectional area is increased, the width of elastic deformation is reduced, which is a disadvantage.

However, according to the configuration of this embodiment as described above, all of these difficulties can be overcome.

Next, FIGS. 7 and 8 show the structure of an FRP 52 suspension arm according to a second embodiment of the present invention.

The structure of this embodiment is such that, as shown in the figure, the same reinforcing fiber is used and the level of ura strength is changed only by changing the winding location and number of windings.

That is, the codes 1 6a, 1 6b, 1 6c are
Flange member 14.14 and ring portions 12a, 12b
The first, second, and third reinforcing fiber layers are wound on the outer peripheral surface of the reinforcing fiber layer. These first to third reinforcing fiber layers 16at 1
6 b + 1 6 c is the notch portion 15 by changing the number of turns sequentially, for example, from 8 turns (first) to 4 turns (second) to 8 turns (third).
It is formed by winding continuously from the inside to the outside in the curve direction.

For example, the first and third reinforcing fiber layers 16 on both sides
a, 16c, especially the axial strength under the compressive load Fp, and especially the third reinforcing fiber layer 16c, when the arm portion 11 is deformed to the state shown by the virtual line in Fig. 3 under the action of the same compressive load. The tensile load strength on the outer peripheral side of the curved surface is borne by each member. The second reinforcing fiber layer 16b located at the center is inevitably formed in the winding process when transitioning from the first reinforcing fiber layer 16a to the third reinforcing fiber layer 16c, and is not necessarily formed. Although not essential,
The ring portions 12a, 12b and the arm portion 11 are integrally secured and share a part of the tensile load Fu shown in FIG. 4.

Therefore, in the configuration of this embodiment, if a compressive load Fp of a predetermined value or more is applied as in the case described above, the arm portion 11 deforms as shown in FIG. 3, thereby absorbing the energy of the compressive load. Absorb as much as possible.

In this case, a large bowing load acts on the outer circumferential surface of the curved part due to the deformation, as shown by arrows (a) and (b), but as mentioned above, this part is subjected to high-strength winding with a large number of windings. Since it is sufficiently reinforced with the third reinforcing fiber layer 16c, high strength is maintained.

Therefore, there is almost no possibility of breakage occurring.

At this time, generally both ends 1 1 8l 1 of the arm portion 11
Near lb, surface distortion occurs due to the out-of-plane bending action of the flange member 14.14 (see points a and b in FIG. 5).

First, from the coupling shaft portions 23a, 23b side, the upper three rubber pushers 22a, 22b, ring portions 12a, 1
The compressive load Fp applied to the arm portion 11 via the arm portion 2b acts in a “wedge” shape on the main body member 13 of the arm portion l1 at the joint portion of the arm portion l1 with the ring portion cylinder body, and I-type both side reinforcing flange member 1 4. 1 and 4 to expand outward.

As a result, the reinforcing fibers, which are arranged only in the vertical direction assuming a compressive load that acts only in a linear direction, begin to buckle in a vertically cracked state, resulting in the bulging strain shown in the figure. I will do it.

In response to such a type of compressive strain, if the configuration of this embodiment is adopted, each of the first to third reinforcing fiber layers 16a=16c
An effective reduction function can be realized by the lashing effect and the energy absorption effect due to elastic deformation over a wide elastic deformation band.

4 In this case, the measured data at points a = d at each part of the left and right strain generating parts at both the front and rear ends of the arm part 11 are shown in graphs as shown in FIGS. 9(a) and 9(b). Become. On the other hand, the regular data of similar conventional examples (Figs. 10 and 11) are shown in Fig. 12 (a) and Fig. 12 (b).
Shown below.

As is clear from comparing these data, although the structure of the second embodiment has fewer turns of reinforcing fibers, the amplitude and magnitude of strain (absolute value ) are both considerably smaller.

In the case of the first embodiment described above, substantially the same effect can be obtained. Furthermore, the same strain reduction effect can be achieved even with respect to the tensile load shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view showing the structure of an FRP suspension arm according to the first embodiment of the present invention, FIG. 2 is a side view of the same, and FIGS. 3 and 4 C are views of the same suspension arm. Schematic diagrams showing elastic deformation states, FIGS. 5 and 6
Each figure is a side view of the arm end showing a local deformation state (distortion state) of the elastically deformed samurai, and FIG. 7 is a structure of an FRP suspension arm according to a second embodiment of the present invention. Fig. 8 is a partially cutaway plan view showing the same side view, Fig. 9 is a partially cutaway plan view showing the
Figures (a) and 9(b) are graphs showing the plots of the second embodiment, respectively. Figure 10 is a partially cutaway side view showing the structure of a conventional FRP suspension arm. Figure 11 is a partially cutaway side view showing the structure of a conventional FRP suspension arm. , the same side view, FIGS. 12(a) and 12(b),
It is a graph showing each effect. 10... FRP' suspension arm 1l...
... Arm parts 12a, 12b -- Ring part ■3 ... Main body member 14 ... Flange member 15 ... Notch part 16a ... First reinforcing fiber layer 16b ... Second Reinforcing fiber layer 16c...Third reinforcing fiber layer Fig. 1 Fig. 2 Fig. 3 FRPII suspension arm Fig. 6 Fig. 11 Compression load 11Fp (&yfl Fig. 12 (b)

Claims (1)

[Claims] 1. In an FRP suspension arm that has a joint part for connecting to the vehicle body and suspension at both ends of the arm part, and is attached between the vehicle body and suspension via the joint part, under a large compressive load of the arm part. An FRP suspension arm structure characterized by arranging fibers with higher strength than other parts in areas where high tensile stress occurs.