JPH0547873Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a vehicle suspension system using FRP leaf springs.

[Prior art]

In addition to reducing the weight of vehicles to improve fuel efficiency, it has been proposed and implemented to use FRP instead of metal for vehicle suspension springs (plate springs interposed between the vehicle body and axle).

The structure of this FRP spring is similar to that of a steel plate spring, and generally, when assembling the spring, a center bolt is passed through to prevent the spring from slipping. I had to drill a hole in the FRP leaf spring to pass the center bolt through. As a result, the reinforcing fibers of the FRP are cut, and the strength around the hole is significantly reduced.

The following ideas have been proposed as means to solve these problems.

(1) Japanese Unexamined Utility Model Publication No. 57-121440, (2) Japanese Unexamined Utility Model Publication No. 57-90437, (3) Japanese Unexamined Utility Model Publication No. 56-122837. It has at least a pair of protrusions located on the left and right sides,
The protrusion is integrally connected to the side surface of the leaf and is configured to protrude laterally.

As is well known, the car body and wheels perform complex movements either independently or together, and when the wheels move up and down relative to the car body, they are supported by an axle with a wheel at the end. A simple vertical force acts on the spring. Even the conventional FRP spring structure can withstand this force.

However, when the wheels move laterally relative to the vehicle body, for example when the vehicle curves, a large lateral force acts on this spring.

The FRP spring invented in (1) above has a pair of protrusions on the left and right sides of the leaf's longitudinal center line, and these protrusions position the U-bolt to fix the spring to the axle. If a spring with this structure is used for a period of time, the U-bolt will loosen or stretch, causing play between the axle and the U-bolt. In this state, there is no longer any resistance to forces pushing the vehicle body in the lateral direction, resulting in loss of steering stability and, in some cases, there is a risk that the spring may break.

Furthermore, the FRP spring with this structure is inherently inferior in lateral rigidity.

In invention (2), a recess is formed on both sides of the center of the spring, a pad is fitted into the recess, and a U-bolt is engaged with a groove formed on the side of the pad to fix it to the axle. be.

However, in this invention, since recesses are formed on both sides of the center of the spring to make the spring thinner, the lateral rigidity is significantly reduced as mentioned above, and there is a high possibility of breakage due to lateral force. It is in.

The idea of (3) is to form a stepped part at the position corresponding to the attachment of the center pin of the leaf spring, and glue the center plate to which the center pin is fixed to this part.
A pair of auxiliary rings are wound between the spring and the end of the center plate.

This invention is excellent in that it can completely prevent the center plate from shifting.
However, as in the case of the above-mentioned known example, there is a problem that no consideration is given to lateral rigidity.

Further, as a prior art related to improving the mounting structure of an FRP leaf spring and an axle case, there is a device disclosed in Japanese Utility Model Application Publication No. 56-42406. According to this prior art, although it is possible to strengthen the mounting structure to some extent, as in the case of the above-mentioned known example, no consideration is given to the lateral (width direction) rigidity, and no consideration is given to the lateral movement of the FRP leaf spring relative to the axle case. Nor.

In addition, since the U bolt directly presses or contacts the axle case, which has a substantially circular cross-sectional shape, the U bolt
The inner shape of the bolt and the outer diameter shape of the axle case do not match, creating a gap, which causes the U-bolt and axle case to deform during use, causing the U-bolt to loosen and need to be re-tightened. be.

Further, in order to support the approximately circular axle case, there are other problems such as the need for a complicated structure that uses elastic pads and plates to disperse stress.

Furthermore, as a prior art regarding stress equalization of leaf springs, there is a device proposed in Japanese Utility Model Publication No. 58-32034.
This prior art relates to a metal multi-layered leaf spring that is made by inserting a bolt into a hole drilled in the center of a plurality of metal overlapping spring plates and tightening them. In order to equalize the stress in the
The width of only a portion of the end of the plate decreases slightly toward the tip, which is completely different from a single-piece FRP plate spring case that is integrally molded. That is, there is nothing that contributes to solving the problems of FRP leaf springs, such as preventing damage to the FRP leaf spring at the mounting position, strengthening lateral rigidity, and preventing lateral movement of the leaf spring with respect to the axle case.

[Problems to be solved with the idea]

As mentioned above, conventional FRP leaf springs for vehicle suspension have weak lateral rigidity and cannot provide sufficient resistance to lateral forces, resulting in lateral displacement and poor handling stability. There was a problem of lack of.

In addition, in conventional FRP body springs, U-bolts are planted on both sides of the spring to restrict the longitudinal and lateral movement of the spring at the same time, so the tightening of the U-bolts may become loose. Or, when it stretches, the connection between the axle case and the spring becomes disconnected,
There were problems with the lack of stability in handling and, in some cases, the springs breaking.

[Purpose of invention]

The present invention was developed in order to eliminate the drawbacks of the above-mentioned conventional vehicle suspension systems that use FRP leaf springs, and its purpose is to
To provide a vehicle suspension system which can strengthen the lateral rigidity of a leaf spring, completely prevent lateral movement with respect to an axle case (axle), and has excellent handling stability.

[Summary of the idea]

The present invention to achieve the above object is to install FRP between two stoppers provided at the top of the axle case.
This suspension system for a vehicle includes a plate spring and a plate-shaped bracket stacked on top of the plate spring, and the bracket and a fixing plate attached to the lower part of the axle case are fastened together using U-bolts.

The FRP leaf spring according to the present invention has an overall shape of an oblong rhombus, with the width at the center being widest to form a fixed part, and extending to both sides to form spring parts. The width of this spring portion gradually decreases toward the end, and at least one
A spectacle part is formed at the end for inserting a fixing pin.

Position regulating parts are formed at both ends of the central fixed part, and stoppers provided on the axle case are brought into contact with these parts to completely prevent lateral movement.

Further, at least one end portion is formed with a goggle portion for locking onto the vehicle body.

In the FRP leaf spring according to the present invention, reinforcing fibers are arranged along the longitudinal direction, and reinforcing fibers are further provided in the central fixed part so as to be perpendicular to the longitudinal direction. Therefore, in the central fixed portion, the reinforcing fibers are arranged crisscrossing in the vertical and horizontal directions.

As reinforcing fibers, inorganic fibers such as carbon fibers, glass fibers, and silicon carbide fibers, or aromatic polyamides (manufactured by DuPont, USA, product name: Kevlar) can be used.
etc. are used.

As the synthetic resin, industrial synthetic resins such as epoxy resins, unsaturated polyester resins, and polyimide resins can be used.

When manufacturing the FRP spring according to the present invention,
It can be manufactured by arranging reinforcing fibers in a certain direction, stacking prelegs in multiple layers, and solidifying this.

Further, in some cases, a high-strength thin metal body can be laminated between the reinforcing fiber layers.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a perspective view of an FRP leaf spring S according to an embodiment of the present invention, and shows a fixed part 1 formed in the center and a fixed part 1 formed on both sides of the fixed part 1, which gradually decreases in width toward the ends. a spring portion 2 and a glasses portion 3 provided at an end of at least one of the spring portions 2;
It is composed of Furthermore, position regulating portions 4 are formed on both sides of the fixed portion 1.

FIG. 2 shows the arrangement of the reinforcing fibers, which are composed of longitudinal fibers f arranged in the longitudinal direction and transverse fibers f' arranged particularly in the fixed portion 1. Therefore, reinforcing fibers are arranged in the fixed part 1 at least in the length and width.

In principle, the FRP leaf spring S according to the present invention does not require consideration such as making the wall thickness thicker in the center and gradually thinner toward the ends in accordance with the moment, unlike conventional leaf springs. A material having a predetermined thickness can also be used satisfactorily.

However, if necessary, the wall thickness may be made thinner at the ends, but as shown in Figure 2, the overall shape is an elongated rhombus, so there is no need to make any major changes to the wall thickness. good.

FIG. 3 shows a case where the FRP spring S according to the present invention is attached to an axle case 10. Stoppers 11 are provided on the left and right sides of the upper surface of the axle case 10, and the fixed portion 1 is attached to the stoppers 11. Position regulating portions 4 formed at both ends are in contact with each other.

Then, a bracket 12 having a warped portion 13 on the end surface is laminated on the upper surface of the FRP spring S, and U-bolts 14 are engaged with both ends of this bracket 12 and inserted into the fixing plate 15, and a nut 16 is attached to the threaded portion. are screwed together and fixed.

[Effect of idea]

The vehicle suspension system according to the present invention includes an FRP plate spring and a plate-shaped bracket stacked on top of the FRP plate spring between two stoppers provided at the upper part of an axle case having at least a flat top surface. and a fixing plate applied to the lower part of the axle case, in which the suspension device is fastened with a U-bolt.
The FRP leaf spring has a generally long diamond shape as a whole, and has a wide fixed part in the center and spring parts extending on both sides of the fixed part, and the fixed part has a widthwise side surface in contact with the stopper, The upper surface is pressed against the upper side of the U-bolt, and has a position regulating part that protrudes from both sides in the longitudinal direction so that the vertical side of the U-bolt passes, and the spring part has a width that gradually decreases on both sides from the fixed part. The reinforcing fibers are arranged at least in the fixed part in a cross shape and in the spring part in the longitudinal direction, so that the following effects are achieved. .

A. FRP leaf springs do not have a hole for passing the center bolt to prevent the spring from slipping, and the fixed part in the center, where it is fastened to the axle case, which is subject to large loads such as impact and weight, is wide and is made of reinforcing fibers. Because they are arranged in a cross shape, they have particularly high rigidity and strength in the lateral direction, sufficiently resisting and absorbing lateral loads, preventing lateral movement and lateral vibration of the vehicle body, and providing stable handling. At the same time, damage to the FRP leaf spring is prevented.

B Axle case due to lateral load and impact
Lateral movement and play between FRP leaf springs should be avoided.
This can be prevented by abutting a stopper against the side surface in the width direction of the position regulating portion.

In addition, since the FRP leaf spring and bracket are stacked on the axle case, which has at least a flat top, and the bracket is fastened with U bolts, the stress caused by the fastening is evenly distributed and the U
There is no deformation or rattling of bolts, axle cases or FRP leaf springs, and no loosening of U-bolts.

C. The position regulating part of the FRP leaf spring is stacked in contact with the stopper of the axle case, and is fastened with U-bolts, so the installation position can be accurately determined, and the simple structure allows for easy and secure installation. can.

D FRP leaf springs are formed from a wide fixed part in the center to spring parts on both sides that gradually reduce in width and are formed into a long diamond shape as a whole, so the thickness of each leaf is almost constant. This is a lightweight FRP leaf spring with a simple shape, which can sufficiently resist the bending moment that acts on it, share the weight of the vehicle, and provide cushioning action.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of an FRP leaf spring, and FIG. 2 is a plan view of the same, showing the arrangement of reinforcing fibers. FIG. 3 is a perspective view showing the FRP leaf spring according to the present invention attached to an axle case. S... FRP leaf spring, 1... Fixed part, 2...
...B part, 3...Glasses part, 4...Position regulating part, f...Vertical fiber, f'...Horizontal fiber, 10...Axle case, 11...Stopper, 12...Bracket, 13...Warpage Part, 14...U bolt, 15
...Fixed plate, 16...Natsuto.

Claims (1)

[Scope of utility model registration request] An FRP leaf spring is placed between two stoppers provided on the upper part of an axle case whose upper part is flat at least, and a plate-shaped bracket is further laminated on top of the leaf spring, and a fixing member is placed between the bracket and the lower part of the axle case. In a suspension system that is connected to a plate using U-bolts, the FRP leaf spring has a generally long diamond shape as a whole, and has a wide fixed part in the center and spring parts extending on both sides of the fixed part, and The fixed portion has a position regulating portion whose widthwise side surface abuts the stopper, whose upper surface is pressed against the upper side of the U bolt, and which protrudes so that the vertical side of the U bolt passes through both longitudinal side surfaces, and The spring portion extends from the fixed portion on both sides while gradually decreasing in width, and has a spectacle portion at the end thereof, and furthermore, reinforcing fibers are provided at least in the fixed portion in a cross shape and in the spring portion in the longitudinal direction. A vehicle suspension system located in