JPS6218772B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a leaf spring structure for a vehicle.

[Conventional technology]

Conventional leaf springs for vehicles use one leaf spring made of spring steel or a plurality of leaf springs stacked together. However, although the plate spring structure made only of spring steel has sufficient robustness, it is heavy due to the use of spring steel with a large specific weight, impairing the reduction in weight of the vehicle, and is not easy to handle.

In order to solve this problem, it has been proposed and used in some cases that leaf springs be made of resin, particularly reinforced fiber plastic, so-called FRP.

[Problem that the invention seeks to solve]

However, although such FRP leaf springs do not have any strength problems during manufacturing, they do not necessarily have sufficient guarantees during long-term use, and due to the characteristics of synthetic resin, they may not be exposed to wind and rain for long periods of time. There are also concerns about whether it will maintain its strength sufficiently when subjected to constant loads and thermal loads.

[Means for solving problems]

According to the present invention, in order to solve the above problems,
A plurality of reinforcing materials made of a metal material are arranged in parallel in the longitudinal direction inside a surface layer portion made of a metal material and welded and integrated with the surface layer portion, and an inner layer portion made of a reinforcing fiber resin material is further laminated on the inside thereof, There is provided a composite leaf spring structure for a vehicle, characterized in that a metal surface layer portion and a resin inner layer portion are integrated into a composite body by sandwiching the metal reinforcing material.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In order to clarify the features of the present invention, first, a specific structure of a conventional leaf spring structure will be explained. Figure 7 shows a conventional leaf spring structure, in which a leaf spring member 1 made of spring steel is shown.
A plurality of sheets are stacked and fastened with clips 3. At this time, the laminated leaf spring members 1 are fastened so that they can be moved slightly relative to each other and not separated from each other. Pins 5 and 5' inserted into eyelets 1a and 1b formed on one of the leaf spring members 1 are pivotally connected to a vehicle body (not shown) directly and via a shackle (not shown). An axle shaft (not shown) is fixed to the center of the leaf spring member 1, so that the leaf spring member 1 absorbs the load acting on the axle shaft.

In the conventional leaf spring structure shown in FIG. 7, the leaf spring member 1 is made of spring steel with a large specific weight, which causes problems in reducing the weight of a vehicle and also causes problems in handling and operability.

In order to solve these problems, it has been proposed and used in some cases that the leaf spring member 1 is made of reinforced fiber plastic. However, when the leaf spring member 1 is entirely made of reinforced fiber plastic as described above, the durability during long-term use is not necessarily sufficiently guaranteed.

Next, referring to FIGS. 1 to 4, the first embodiment of the present invention will be described.
An example will be explained. Although the first embodiment of the present invention has a single-layer leaf spring structure consisting of one leaf spring member 11, a plurality of leaf spring members 11 may be laminated to form a multi-layer leaf spring structure (not shown). In FIG. 1, a leaf spring member 11 has a surface layer 13 made of a thin plate of spring steel such as SUP specified in JIS G4801, and an inner layer made of a resin layer such as epoxy resin reinforced with reinforcing fibers such as glass fiber or carbon fiber. Part 15
are combined into one. Since the metal material forming the surface layer 13 and the reinforcing fiber resin material forming the inner layer 15 have significantly different coefficients of thermal expansion, there is a concern that peeling may occur due to this.
Through a convex portion formed in and protruding into the inner layer portion 15,
In addition to or in place of adhesive bonding, mechanical bonding means shall be employed.

In the first embodiment, reinforcing members 17 made of the same or similar material as the surface layer 13 are arranged in the longitudinal direction at appropriate intervals on the back surface of the surface layer 13 (see FIG. 2). is fixed to a metal material such as spring steel constituting the surface layer 13 by seam welding or spot welding. Furthermore, the end of the surface layer 13 is bent into a circular shape so as to surround the bush 21, and the tip 13a is bent.
is welded to the folded surface layer 13 at an acute angle (FIG. 1). As shown in FIG. 2, horizontal reinforcing members 19 are fixed near the tip 13a by seam welding or spot welding at approximately equal intervals in a direction intersecting the vertical reinforcing members 17. The horizontal reinforcing member 19 is made of the same material as the vertical reinforcing member 17, and the cross-sectional shape of the reinforcing members 17, 19 may be polygonal, such as a square or a pentagon, in addition to the circular shape shown in FIGS. 3 and 4. The inner layer 15 is a convex reinforcing member fixed to the surface layer 13 by molding a reinforcing fiber resin material, such as an epoxy resin impregnated with 60 to 70% glass fiber, constituting the inner layer 15 on the back surface of the surface layer 13. 17, 19 over a wide area and reinforcing members 17, 1.
Peeling is prevented by improving the bonding strength by mechanically bonding the inner layer portion 9 to the inner layer portion 15 by forming irregularities.

In the first embodiment, a composite beam is formed by integrating a surface layer made of a metal material and an inner layer made of reinforcing fiber with different moduli of elasticity. Therefore, compared to a case where the entire structure is made of reinforcing fibers, the strength can be increased for the same size, and the size can be reduced for the same strength. Furthermore, the weight can be significantly reduced compared to when everything is made of metal. In addition, even if the inner layer is damaged for some reason, the load can be borne by the surface layer, so the leaf spring member will not be damaged immediately, and until the leaf spring is damaged, the driver will be affected by increased vehicle vibration due to damage to the inner layer. Abnormalities can be detected and treated.

Next, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. As shown in FIG. 5, in the second embodiment, an inner layer portion 15 made of reinforced fiber resin is integrated by sandwiching two surface layer portions 13 and 13'. That is, the tip of the surface layer 13 is bent into a circular shape so as to surround the bush 21, and the leading edge 13 is bent.
A is bent at an acute angle and seam welded or spot welded to the surface layer 13. A plurality of reinforcing members 17 each having a circular or appropriate cross-sectional shape are placed on the back surface of the surface layer 13 in the longitudinal direction and are seam-welded or spot-welded. Another surface layer 13' is positioned parallel to the surface layer 13 with a predetermined gap, and the tip of the surface layer 13' is concentrically bent with the bush 21, and the leading edge 13'a is bent at an acute angle. Seam welding or spot welding is performed on the tip 13a of 13. Surface layer 13'
Lateral reinforcing members 19 are placed at equal intervals across the longitudinal direction of the inner surface and are seam welded or spot welded. A reinforcing fiber resin material is laminated and molded between the surface layer parts 13 and 13'. Note that the surface layer 13,1
3', the materials of the inner layer portion 15 and the reinforcing members 17 and 19 are the same as in the first embodiment.

In the second embodiment, the surface layer made of a metal material that is strong against tensile stress is located on both sides of the inner layer made of a reinforced fiber resin material that is strong against compressive stress, so that sufficient strength can be exhibited regardless of the direction of the load acting on the spring member. As in the first embodiment described above, the surface layer made of metal material and the inner layer made of reinforcing fiber are integrated into a composite structure to form a combined beam, thereby increasing strength and reducing weight. Furthermore, even if the inner layer is damaged for some reason, the load can be borne by the surface layer, and the driver can take measures due to the increase in vehicle vibration. Further, in this embodiment as well, the reinforcing member engages with the inner layer portion in an uneven manner, thereby improving the mechanical bonding strength.

〔Effect of the invention〕

As described below, the present invention can significantly reduce the weight compared to the case where the leaf spring is made entirely of metal materials, although it is not as great as when the leaf spring is made entirely of reinforced fiber resin material, and the leaf spring of the present invention is made of metal materials. Since the surface layer part and the inner layer part made of reinforcing fiber resin are composited and integrated, the surface layer part and the inner layer part share and bear the stress generated by the load acting on the leaf spring due to the effect of the combined beam. For this reason, it is possible to reduce the weight and improve the strength compared to a leaf spring that simply laminates a metal body and a fiber resin material.

Further, according to the present invention, the weight of the composite leaf spring structure is reduced by combining the metal surface layer and the reinforcing fiber resin inner layer, and the reinforcing material is made by welding the metal surface layer and the reinforcing fiber resin inner layer to the metal surface layer. Since the composite is integrated through the convex portion formed by the above, the bonding area is large, the bonding strength is improved, and separation between the two layers is prevented, resulting in a composite leaf spring structure with high strength and improved durability. . Furthermore, the presence of the reinforcing material improves the overall strength of the leaf spring, making it suitable as a leaf spring structure for vehicles.

[Brief explanation of the drawing]

1 is a front view of the first embodiment of the present invention, FIG. 2 is a view taken along the - arrow in FIG. 1, FIG. 3 is an enlarged view of a portion of FIG. 5 is a perspective view of a second embodiment of the present invention, FIG. 6 is an enlarged view of a portion of FIG. 5, and FIG. 7 is a perspective view of a conventional device. 11...Plate spring member, 13, 13'...Surface layer part, 1
5... Inner layer part, 17... Reinforcement material, 19... Lateral reinforcement material.

Claims (1)

[Claims] 1. A plurality of reinforcing materials made of a metal material are arranged in parallel in the longitudinal direction inside a surface layer portion made of a metal material, welded and integrated with the surface layer portion, and an inner layer portion made of a reinforcing fiber resin material is further laminated on the inside thereof, A composite plate spring structure for a vehicle, characterized in that the metal surface layer portion and the resin inner layer portion are integrated into a composite body by sandwiching the metal reinforcing material.