JPS632715A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To make a suspension lightweight and small-sized and increase the deflection quantity by inserting a pivot shaft into the coil section of a twisted coil-shaped FRP spring, unrotatably hooking one end of the spring to a vehicle body, and connecting the other end to a link so that the link is rotated to the ground side. CONSTITUTION:A suspension spring 11 is formed with FRP into a coil spring shape, a pivot shaft 2 is inserted into a coil section 12, and the coil section 12 is rotatably constituted against a cylindrical body 2b. The arm section 13 of the spring 11 is connected to a member 11 on the vehicle body side with a connecting member 16, and a section of an upper link 6 with a connecting member 17. Thereby, the spring 11 is twisted in the rewinding direction by the upward rotation of the link 6, and a wheel is energized downward by its reaction force via the link 6. According to this constitution, a suspension is made small-sized and lightweight, and its vertical stroke can be fully increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle suspension system used in an automobile suspension system.

[Conventional technology]

Various types of vehicle suspension systems have been known. For example, a traditional suspension system using vertical steel spring suction devices has eyelets at both ends of the spring plate, and these eyepieces are connected to the vehicle body, with the center point in the longitudinal direction of the spring plate. The axle housing is fixed to the part.

Additionally, in independent suspension systems, suspensions that use steel coil springs as suspension springs are often used, as typified by MacPherson struts, double wishbones, and the like.

[M points while the invention is trying to solve]

In order to improve riding comfort, it is desirable to increase the vertical stroke of the wheels. However, in a suspension system using conventional steel spring plates, the spring plate needs to be considerably long in order to increase vertical deflection. However, since there is a natural limit to the space available for installing temporary springs, it is not possible to make the temporary springs unnecessarily long, and they are also quite heavy.

On the other hand, in order to increase the vertical stroke of a suspension system using a fill spring, the height of the coil spring becomes large. However, since there are restrictions on the spring housing space of the vehicle body frame and suspension mechanism, there is naturally a limit to the height at which the coil spring can be installed.

Under these circumstances, it has been desired to develop a suspension device that has a suspension spring that can be stored in a relatively narrow space and that can provide sufficient deflection.

[Means for solving problems]

INDUSTRIAL APPLICATION This invention is applied to the suspension system for vehicles which supports a wheel via the suspension link which is pivotally connected to the member of the vehicle body side so that it can swing in the vertical direction about a pivot shaft. The link is, for example, an upper link (upper arm) or a lower link (lower arm). The suspension device of the present invention uses an FRP spring shaped like a torsion coil spring as a suspension spring. This FRP spring is made by embedding unidirectional continuous reinforcing fibers such as glass fibers or carbon fibers mainly in the longitudinal direction of the spring and hardening the matrix resin. Then, the pivot shaft is inserted through the coil part of the FRP spring, one end of the torsion coil spring is locked to the vehicle body side member, and the other end of the torsion coil spring is rotated toward the ground side. It is coupled to a portion of the link so as to be dynamically biased.

[Effect]

In the suspension system configured as described above, when the link swings in the vertical direction as the wheel moves up and down, the suspension spring bends with this movement. The coil part of this FRP spring is wound around the pivot shaft of the link, and the end part can be placed along the vehicle body member and the link, so it can be used in suspension mechanisms with severe space constraints. Can be integrated. However, this type of spring is limited by the up and down stroke of the wheel.

In order to ensure this, a fairly large deflection is required.

If the suspension spring is made of steel, it is not suitable for practical use because it cannot be bent to a large extent due to the relationship between the bending elastic modulus of steel and the allowable strain magnitude. However, FRP materials in which unidirectional continuous reinforcing fiber bundles such as glass fibers or carbon fibers are embedded in a matrix resin can be bent approximately twice as much as steel due to the relationship between the bending elastic modulus and the magnitude of strain. In terms of material mechanics, when a constant load is applied to a plate of constant width and length, the maximum amount of deflection allowed is proportional to 71-. E is the flexural modulus, and ε is the strain that can withstand repeated use. In other words, the amount of deflection of FRP that can withstand repeated bending is sufficiently larger than that of steel, so like the torsion coil spring mentioned above, it is connected to the link and the member on the car body side, and bending acts on it. Sufficient deflection for practical use can be obtained in the suspension spring.

〔Example〕

In the vehicle suspension system shown in FIG. 1, there are pivot shafts 2.
3 is provided. The vehicle body side member 1 is a vehicle body frame, subframe, or the like.

A suspension link mechanism 5 is provided on the vehicle body side member 1. That is, an upper link 6 is pivotally connected to the upper pivot shaft 2, and a lower link 7 is pivotally connected to the lower pivot shaft 3 so as to be able to swing vertically. As illustrated in FIG. 2, the pivot shaft 2 includes a shaft 2a provided between a pair of support portions 1a and lb;
It consists of a cylindrical body 2b and the like placed over the outside of the shaft 2a. The shaft 2a is fixed by a nut 8.

The links 6.7 protrude in the vehicle width direction like the well-known double wishbone type, and a knuckle 9 is attached to the tip of each link 6.7.

A wheel 1O is rotatably supported on the knuckle 9.

Note that a shock absorber (not shown) is provided between the lower link 7 and the vehicle body side member 1. A similar suspension link mechanism is also provided on the right side of the vehicle body side member 1 in the figure.

The link mechanism 5 is provided with a torsion coil spring-like FR.
A suspension spring 11 made of P is used.

This FRP spring 11 is made by impregnating a well-known unidirectional reinforcing fiber bundle, such as glass fiber or carbon fiber, which is continuous in the longitudinal direction with a matrix resin, and then molding and hardening it into a predetermined shape. 12, and arm portions 13 and 1 on both end sides.
4. The arms 13.14 are substantially straight or slightly curved. In addition, the coil part 12 and the arm part 1
The cross-sectional shape of 3°14 is a rectangle (thickness t1 width b) as shown in FIG. The FRP spring 11 having a rectangular or square cross-section as in this embodiment can store more energy than one with a circular cross-section, so it can be made smaller and easier to manufacture.

The pivot shaft 2 is inserted through the coil portion 12 of the spring 11. That is, in the case of this embodiment, the cylindrical body 2
A coil portion 12 is wound on the outside of b. Coil part 12
The inner diameter of the coil portion 12 is larger than the outer diameter of the cylindrical body 2b, and therefore the coil portion 12 is rotatable relative to the cylindrical body 2b. Cylindrical body 2
b is preferably made of synthetic resin in order to prevent wear of the FRP spring 11. When the cylindrical body 2b is made of metal, the cylindrical body 2b
A synthetic resin liner (not shown) may be interposed between the FRP spring 11 and the FRP spring 11 to prevent wear.

Further, the negative arm portion 13 is connected to the vehicle body side member 1 by a connecting member 16, and the other arm portion 14 is connected to the end of the upper link 6 by a connecting member 17. Therefore, when the link 6.7 is rotated upward, the spring 11 is twisted in the unwinding direction, and the repulsive force of the spring 11 urges the link 6.7, that is, the knuckle 9 and the wheel 10 downward, that is, toward the ground. Therefore, in this embodiment, when a load is applied, the inside of the coil section 12 becomes the tension side (pulling surface side), and the outside of the coil section 12 becomes the compression side (compression surface side). preferable.

In a curved portion such as the coil portion 12, the smaller the radius of curvature, the greater the strain on the inside of the curve compared to the strain on the outside of the curve.

Due to its nature, the strength of the reinforcing fibers in the tensile direction, ie, the tension side, is higher than the strength in the compression direction, ie, the compression side. Therefore, when using an FRP material that is weak against compression, it is advantageous in terms of strength to use it so that the tension side is mainly on the inside of the bend.

As mentioned above, when a constant load is applied to a material of -constant width and -constant length, the maximum deflection plate that can be used repeatedly is proportional to f7 plates. Table 1 below shows the results of an experiment comparing conventional spring steel with test pieces made of glass fiber reinforced synthetic resin (GFRP) and carbon fiber reinforced synthetic resin (CFRP) developed by the present inventors.

Table 1 From Table 1, the 2-knee τ of GFRP is 2.4 times that of spring steel, and that of CFRP is 1.6 times that of spring steel.
FRP can withstand the greatest amount of repeated deformation.

A shape model of the FRP spring 11 is shown in FIG.

The following Table 2 shows the spring 11 made of GFRP and CFRP.
These are the results of comparing those made of steel with those made of spring steel. The elastic modulus E and strain ε were set to the values shown in Table 1. Further, the maximum load was set to 140 A'g-' in terms of torque. The expanded length of the spring is approximately 700M.
is constant. The deflection 6 is the total displacement of the pivot shaft 2 at a position of 350 mm from the center of rotation. Considering practicality, two types of plate widths were considered: 30111111 and 20mm.

Table 2 When the FRP spring 11 having the shape and dimensions described above is used in the suspension system shown in FIG. 1, a maximum deflection δmax of 150 mm or more is practically desired. From Table 2, calculate soil 1 (
Springs made of GFRP and CFRP satisfy this condition, but steel springs lack sufficient flexibility.

According to research by the present inventors, in order to obtain a deflection that can be mounted on an actual vehicle with the spring 11, f100T -0, O75KgfT
It is necessary to use a material with a diameter of /mm or more.

Although such a value is not possible with steel, it can be achieved by using FRP.

In addition, as shown in FIGS. 5 and 6, -pair FR
It is also possible to combine springs 11 and 11' made of P. In this case, the winding directions of the springs 11, 11' are opposite to each other. and - end Xla.

11a' is fixed to the member 1 on the vehicle body side
By locking at 0.20', the spring 11°11
′ does not rotate. The other end 11b, l
lb' is connected to the link 6 side by a connecting member 17.

The present invention can also be applied to suspension systems using links other than the double wishbone type. Further, the cross-sectional shape of the spring 11 is not only rectangular but also circular and oval.

Oval cross sections can also be used.

〔Effect of the invention〕

According to the present invention, a sufficient vertical stroke can be obtained even though a suspension spring that can be incorporated into a suspension mechanism with severe space constraints is used, and in addition, the suspension spring is made of FRP. Compact and lightweight parts;
This has a great effect on promoting

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing a part of a suspension system according to an embodiment of the present invention in partial cross section, FIG. 2 is a plan view of a part of the suspension system shown in FIG. 1, and FIG. FIG. 4 is a perspective view showing an example of an FRP spring, and FIG. 4 is a cross-sectional view of the spring shown in FIG. 3 taken along line -IV. FIG. 5 is a plan view of a part of a suspension system showing another embodiment of the present invention, and FIG. 6 is a perspective view of a part of the suspension system shown in FIG. 1... Vehicle body side member, 2.3... Pivot shaft, 6.
7...Link, 10...Wheel, 11...F RP
'M spring, 11a, 11b... end of spring, 12...
・Coil part, 13.14... Arm part (spring end). Applicant's agent Patent attorney ± 8 Takehiko E Figure 1 Figure 5

Claims (2)

[Claims] (1) In a vehicle suspension system that supports wheels via a suspension link that is pivotally connected to a member on the vehicle body side so as to be able to swing vertically around a pivot shaft, it is made of FRP formed in the shape of a torsion coil spring. The pivot shaft is inserted through the coil part of the suspension spring, and one end of this FRP spring is locked to the vehicle body side member so as not to rotate, and the other end is connected to the link by this spring. A suspension system for a vehicle, characterized in that the suspension system is connected to the link so as to be rotationally biased toward the ground. (2) The FRP spring is installed such that the inside of the coil part becomes the tension side and the outside of the coil part becomes the compression side when a load is applied. suspension system for vehicles.