Resin-based fiber composite leaf spring body and method for manufacturing same, leaf spring assembly

Abstract

The application discloses a resin-based fiber composite material plate spring body, which has a parabolic structure, wherein a concave parabola is the upper surface of the plate spring body, a convex parabola is the lower surface of the plate spring body, and the surface adjacent to the upper surface and the lower surface is the side surface of the plate spring body; the upper surface and the lower surface of both ends of the plate spring body respectively comprise metal plates which are embedded in the plate spring body. The composite material plate spring can effectively prolong the service life of the plate spring.

Description

Technical Field

[0001] The present invention relates to a leaf spring overall structure of an automobile suspension, and more particularly to a composite leaf spring assembly structure for an automobile. Background Art

[0002] With the increasing global consumption of fossil fuels and growing awareness of environmental issues, the pace of innovation in new materials and technologies in the automotive industry is accelerating. Lightweighting vehicles not only significantly reduces fossil fuel consumption but also increases cargo capacity and vehicle efficiency. Resin-based fiber composites, in addition to their light weight and high specific strength, also offer excellent shock absorption and fatigue life. Consequently, they are widely used in the automotive industry.

[0003] Resin-based fiber composite materials, as leaf spring materials for automobiles, have been widely researched by many automobile manufacturers in recent years and have also been commercially used in some car models.

[0004] As a new automotive component, resin-based fiber composite leaf spring assemblies present numerous challenges in assembling the leaf spring material with components such as the axle and lugs due to the properties of composite materials. For example, during lug installation, the metal lugs must be connected and secured to the composite leaf spring using through-hole bolts. However, these holes disrupt the composite material's internal fiber structure, creating stress concentrations near the holes during use. This can cause the leaf spring to tear along these stress concentration areas, ultimately aging the composite leaf spring and damaging the leaf spring assembly structure. Summary of the Invention

[0005] Based on one of the problems that arise when using the above-mentioned composite materials as automobile leaf spring materials, the present invention proposes a resin-based fiber composite leaf spring assembly structure, which effectively improves the service life of the resin-based fiber composite leaf spring while meeting the lightweight requirements of automobile leaf springs.

[0006] In a first aspect, a resin-based fiber composite leaf spring body is provided, wherein the leaf spring body has a parabolic structure, the concave parabola is the upper surface of the leaf spring body, the convex parabola is the lower surface of the leaf spring body, and the side surfaces of the leaf spring body are adjacent to the upper surface and the lower surface. The invention is characterized in that the upper and lower surfaces at both ends of the leaf spring body respectively include metal plates, and the metal plates are embedded in the leaf spring body.

[0007] In a possible implementation manner of the first aspect, the upper surface and / or lower surface of the central area of ​​the leaf spring body includes a metal plate, and the metal plate is embedded in the leaf spring body.

[0008] In a possible implementation of the first aspect, the upper and lower metal plates at both ends of the leaf spring body respectively include multiple metal plates, and the metal plates are embedded in the resin-based fiber composite material. The metal plates between the upper and / or lower sides of the central area of ​​the leaf spring body include multiple upper metal plates, and the metal plates are embedded in the leaf spring body.

[0009] In a possible implementation manner of the first aspect, side surfaces of the central area of ​​the leaf spring body respectively include metal plates, the metal plates are embedded in the leaf spring body, and the metal plates include at least one rectangular parallelepiped protrusion.

[0010] In a possible implementation of the first aspect, the metal plates respectively included on the upper and lower surfaces of the two ends of the leaf spring body, the metal plates respectively included on the upper and / or lower surfaces of the central area of ​​the leaf spring body, or the metal plates respectively included on the side surfaces of the central area of ​​the leaf spring body have a length of 20 mm to 200 mm along the length direction of the leaf spring body, and a thickness along the thickness direction of the leaf spring body of 0.1 mm to 80 mm.

[0011] In a possible implementation of the first aspect, the metal plates respectively included on the upper and lower surfaces of the two ends of the leaf spring body, the metal plates included on the upper and / or lower surface of the central area of ​​the leaf spring body, or the metal plates respectively included on the side surfaces of the central area of ​​the leaf spring body, facing the resin-based fiber composite material, are concave-convex contact surfaces.

[0012] In a possible implementation manner of the first aspect, the concave-convex contact surface of the metal plate includes conical protrusions or polygonal conical protrusions on the surface of the metal plate.

[0013] In a possible implementation of the first aspect, the metal plates at both ends of the leaf spring body are provided with at least one bolt hole, the depth of the bolt hole is less than or equal to the thickness of the metal plate, and the metal plate below the central area of ​​the leaf spring body is provided with a positioning hole, the depth of the positioning hole is less than or equal to the thickness of the metal plate.

[0014] In a possible implementation of the first aspect, the metal plates at both ends of the leaf spring body are provided with at least one through-hole bolt hole, and the through-hole bolt hole generates a through hole in the metal plate and the resin-based fiber composite material along the thickness direction of the two ends of the leaf spring body, and the central area of ​​the leaf spring body is provided with a through-hole positioning hole, and the through-hole positioning hole generates a through hole in the metal plate and the resin-based fiber composite material along the thickness direction of the central area of ​​the leaf spring body.

[0015] In the second aspect, a resin-based fiber composite leaf spring assembly is provided, comprising the leaf spring body, metal ear, and fastening bolts described in any one of the first aspects, the metal ear comprising a frame hinge tube and a leaf spring clamping plate, the leaf spring clamping plate and the frame hinge tube forming a U-shaped structure, and the leaf spring clamping plate of the metal ear is fixedly connected to the leaf spring body by a fastening bolt.

[0016] In a third aspect, a resin-based fiber composite leaf spring assembly is provided, comprising the leaf spring body, metal ear, fastening bolts, and a U-shaped metal cover plate described in any one of the first aspects, wherein the metal ear comprises a frame hinge tube and a leaf spring clamping plate, the leaf spring clamping plate and the frame hinge tube form a U-shaped structure, the leaf spring clamping plate of the metal ear is fixedly connected to the leaf spring body by fastening bolts, and the U-shaped metal cover plate comprises at least one U-shaped groove, and the U-shaped groove matches the rectangular protrusion of the metal plate on the side of the central area.

[0017] Fourthly, the present invention provides a method for manufacturing a leaf spring body. The specific steps are as follows:

[0018] 1. Dry the formed glass fiber;

[0019] In this step, the raw glass fiber is dried in a drying oven at 150°C to remove moisture from the glass fiber. In the present invention, glass fiber is used as the reinforcement material of the resin-based fiber material, but the present invention is not limited to this. Other reinforcing fibers such as carbon fiber can also be used. The drying method can also be selected from air drying or other methods according to the specific material properties. Of course, this drying step can also be omitted depending on the material conditions.

[0020] 2. Arrange the glass fibers according to a preset path to preform the glass fibers;

[0021] In this step, the glass fibers are arranged according to the shape of the designed leaf spring to form a glass fiber leaf spring preform.

[0022] 3. Place the glass fiber preform in step 2 in a mold with a matching shape. The mold has grooves at both ends and in the middle for placing the metal plate. The grooves match the shape of the metal plate and the depth of the grooves is less than or equal to the thickness of the metal plate.

[0023] In this step, the molding machine applies pressure to the preform through the mold. For leaf springs with metal plates at both ends and in the middle, the mold is provided with grooves for the metal plates. In some embodiments, the side surfaces of the mold may also have grooves, with the depth of the grooves being less than or equal to the thickness of the metal plates.

[0024] 4. Inject resin into the mold in step 3 under high pressure while applying pressure to the preform;

[0025] 5. demolding, completing the leaf spring body product.

[0026] In a fifth aspect, the present application provides a method for manufacturing a composite material leaf spring body, specifically comprising:

[0027] 1. drying the formed glass fiber;

[0028] In this step, the raw material glass fiber is dried in a drying box at 150°C to remove moisture in the glass fiber. In the present application, glass fiber is used as the reinforcing material of the resin-based fiber material, but the present application is not limited thereto, and other reinforcing fibers such as carbon fiber can also be used, and the drying method can also be air drying or other methods according to the specific material properties, of course, the drying step can also be omitted according to the material situation.

[0029] 2. arranging the glass fiber according to the preset path to preform the glass fiber;

[0030] In this step, the glass fiber is arranged in layers according to the shape of the designed leaf spring. According to the thickness of the arrangement, when a metal plate is needed, after completing the arrangement of the previous layer of fiber, the middle layer of metal plate is placed on the glass fiber, and then the next layer of fiber is arranged. When it is necessary to place a metal plate again, repeat the process, and determine the number of metal plates to be placed according to the design requirements, and then complete the preform. The preform can include multiple metal plates at both ends and in the middle region.

[0031] 3. placing the glass fiber preform in step 2 in a mold matched in shape, the mold being provided with grooves for placing metal plates at both ends and in the middle, the grooves being matched in shape with the metal plates, and the groove depth being less than or equal to the thickness of the metal plate;

[0032] In this step, the mold press applies pressure to the preform through the mold. For the leaf spring body including metal plates at both ends and in the middle, the mold is provided with grooves for placing metal plates at both ends and in the middle. The groove depth is less than or equal to the thickness of the metal plate. The metal plate added in this step is the metal plate on the surface of the leaf spring body. The thickness of the metal plate can be the same as that in step 2, or different from that in step 2.

[0033] 4. high-pressure injection of resin into the mold in step 3 while applying pressure to the preform;

[0034] 5. demolding, completing the leaf spring body product. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a schematic view of a commonly used resin-based fiber composite material leaf spring assembly;

[0036] Figure 2 is a schematic diagram of another resin-based fiber composite leaf spring assembly;

[0037] Figure 3 1. This is a front view schematic diagram of a resin-based fiber composite leaf spring assembly provided by an embodiment of the present application;

[0038] Figure 4 This is a three-dimensional schematic diagram of a resin-based fiber composite leaf spring assembly provided by an embodiment of the present application;

[0039] Figure 5 This is a schematic diagram of the arrangement of the metal plate at one end of the leaf spring and the fibers in the resin matrix in an embodiment of the present application;

[0040] Figure 6 This is a front view schematic diagram of a resin-based fiber composite leaf spring assembly provided by another embodiment of the present application;

[0041] Figure 7 This is a front view schematic diagram of a leaf spring assembly having a resin-based composite material provided by another embodiment of the present application;

[0042] Figure 8 is a schematic diagram of the interaction force between the leaf spring body and the through-hole bolt in an embodiment of the present application;

[0043] Figure 9 is a schematic diagram of the interaction force between the leaf spring body and the through-hole bolt in an embodiment of the present application;

[0044] Figure 10a This is a schematic diagram of the structure of the middle area of ​​the leaf spring body in another embodiment of the present application;

[0045] Figure 10b is a schematic top view of a metal plate matching the structure of the middle region of a leaf spring in yet another embodiment of the present application;

[0046] Figure 11a This is a front view schematic diagram of a metal plate structure in yet another embodiment of the present application;

[0047] Figure 11b This is a schematic top view of a metal plate structure in yet another embodiment of the present application;

[0048] Figure 12 This is a three-dimensional schematic diagram of the metal curling ear in the embodiment of the present application;

[0049] Figure 13 This is a schematic diagram of a resin-based fiber composite leaf spring assembly according to another embodiment of the present application. DETAILED DESCRIPTION

[0050] The following is a further description of specific embodiments of the present invention with reference to the accompanying drawings.

[0051] Figure 1 A commonly used resin-based fiber composite leaf spring assembly is shown. The assembly includes a composite leaf spring and a coil ear. The coil ear is fixedly connected to the two ends of the leaf spring by a through-hole bolt. A through-hole is provided in the middle of the leaf spring, which is used to position the leaf spring with the axle via a center bolt. During use, the coil ears at both ends of the leaf spring are connected to the car body. After the middle of the leaf spring is positioned and matched with the axle via a center bolt, the leaf spring is fixed to the axle via a U-bolt, thereby forming a suspension assembly between the car body and the axle (axle). The through hole in the middle of the leaf spring can pass through the leaf spring in a vertical direction. The center bolt cooperates with the positioning protrusion and positioning groove on the axle to achieve the positioning installation of the leaf spring and the axle.

[0052] In some embodiments, as Figure 2 As shown in , the leaf spring body fixed to the axle includes a protrusion below the middle part, and a metal plate matching the protrusion can be assembled on the lower part of the protrusion. The groove formed by the metal plate can tightly fix the protrusion of the leaf spring body. The bottom of the metal plate also includes a metal locating pin, which can match the locating hole in the axle. The metal parts on the metal plate axle are separated from the composite material, and the front and rear longitudinal forces generated during the vehicle's driving are transmitted through the protrusion on the leaf spring body, thereby reducing the wear of the leaf spring on the axle and avoiding damage to the leaf spring body caused by drilling holes in the leaf spring body. In this embodiment, a protruding locating pin is provided on the metal plate, and a locating hole is provided on the axle. The locating hole cooperates with the metal protruding locating pin of the leaf spring to achieve the positioning installation of the leaf spring and the axle.

[0053] Figure 3 The present invention illustrates a resin-based fiber composite leaf spring assembly. The composite leaf spring assembly comprises a composite leaf spring body and two metal ears. The leaf spring body has a parabolic structure, with a concave parabola forming the upper surface and a convex parabola forming the lower surface. The surfaces adjacent to the upper and lower surfaces form the side surfaces of the leaf spring body. The upper and lower surfaces of the leaf spring body, respectively, comprise metal plates 1a and 1b, embedded within the leaf spring body. The metal plates at each end are provided with at least one bolt hole, the depth of which is less than or equal to the thickness of the respective metal sheet. The bolt hole can be fixedly connected to the metal ear via a bolt rod. The upper and / or lower surfaces of the central region of the leaf spring body comprise metal plates 2a and 2b, embedded within the leaf spring body. The lower metal plate in the middle of the leaf spring comprises at least one locating hole that mates with a locating pin protruding from the axle. Specifically, in the implementation of the present invention, the positioning hole can be 5mm-30mm in diameter, the bolt holes on the metal plates at both ends of the leaf spring body can be 4-20mm, the width of the metal plates at both ends of the leaf spring body can be less than or equal to the width of the resin-based fiber leaf spring, the length can be 20mm-200mm, and the thickness can be 0.1mm-5mm.

[0054] The metal plate embedded in the leaf spring body referred to in the invention means that during the forming process of the resin-based fiber composite leaf spring, the metal plate is integrally formed with the resin-based fiber material through a specially designed mold through a molding machine, so that the metal plate is embedded in the resin-based material to form a firm bond.

[0055] Optionally, in some embodiments, the lower metal plate in the middle of the leaf spring may be provided with a positioning pin, such as Figure 3 As shown in 3, positioning holes are set at the matching parts of the axle to achieve the positioning of the axle and the leaf spring body.

[0056] Optionally, in some embodiments, the upper surface of the metal plates at both ends and / or the middle of the leaf spring body may be higher than the surface of the resin-based fiber composite material. Figure 3 As shown in the enlarged view of the metal ear at the left end of the middle leaf spring, the surface of the metal plate above the left end of the leaf spring is higher than the upper surface of the resin-based fiber matrix. It should be understood that the height difference between the upper surface of the metal plate and the upper surface of the resin-based fiber matrix can be determined based on the actual forming mold. Those skilled in the art can achieve this height difference without significant inventive effort, resulting in superior overall performance.

[0057] For the leaf spring body made of resin-based fiber composite materials, during the forming process, the fibers are stretched in a one-dimensional arrangement along the length of the leaf spring. The higher the degree of alignment of the fibers along the length of the leaf spring, the better the overall mechanical properties of the leaf spring after being composited with the resin and fiber materials. Therefore, during the leaf spring forming process, technicians always hope to use various methods to keep the fibers straight along the length of the leaf spring. Figure 4 A schematic diagram of the fiber arrangement within the resin-based fiber composite material matrix at one end of the leaf spring body of the present invention is shown. The figure schematically illustrates multiple fiber filaments arranged straight within the resin matrix, with fiber filaments 1, 2, and 3 located near the upper surface of the resin matrix. At the contact point between the leaf spring and the metal plate, the deeper the metal plate is embedded in the resin matrix—that is, the smaller the height difference between the upper surface of the metal plate and the upper surface of the resin-based fiber plate—the more severe the fiber bending at the junction of the metal plate and the matrix. Consequently, the bent fibers near the metal plate at the end of the spring degrade their mechanical properties. Therefore, in some embodiments, this height difference can be increased to maintain the fibers near the metal plate in a nearly straight state, improving the bonding between the metal and the resin-based fiber body while maintaining the mechanical properties of the resin-based fiber material.

[0058] Figure 4 A three-dimensional schematic diagram of a leaf spring assembly of this embodiment is shown.

[0059] During the assembly process with the car, the following steps can be followed:

[0060] Insert either end of the leaf spring body between the U-shaped metal plates of the metal ears, and securely connect the metal ears to the upper and lower metal plates of the leaf spring body with fastening bolts;

[0061] Place the axle, the leaf spring body with coiled ears, and the metal clamping plate on the U-bolt from bottom to top. Fit the positioning hole of the lower metal plate in the middle of the leaf spring with the positioning bolt on the axle. Install the U-bolt and clamp and fix the leaf spring and the axle with the U-bolt.

[0062] Assemble the leaf spring assembly ears at the frame leaf spring connection points or hinge points to complete the installation of the composite leaf spring assembly.

[0063] Optionally, in some embodiments, the central portion of the leaf spring body may comprise only a lower metal plate, which is embedded in the leaf spring body during the composite leaf spring forming process. When the central portion of the leaf spring body comprises only the lower metal plate, the composite leaf spring assembly structure further includes a rubber pad positioned between the upper metal plate of the U-bolt and the leaf spring body to prevent direct contact between the upper metal plate of the U-bolt and the composite plate, which could cause wear and damage to the composite leaf spring.

[0064] During the assembly process, the metal plate, rubber pad, and leaf spring body on the U-bolt are stacked from top to bottom and matched with the axle locating pin, then clamped and fixed to the axle by two U-bolts, and the coil ear is installed on the corresponding leaf spring hinge point on the frame.

[0065] The leaf spring assembly structure proposed by the invention does not require a perforated structure in the leaf spring body, which can effectively avoid damage to the resin-based fiber composite material by metal bolts and improve the service life of the leaf spring.

[0066] Alternatively, in another embodiment, as shown in the attached Figure 6 As shown, the metal plates at both ends of the leaf spring body are provided with at least one through-bolt hole. This through-bolt hole creates a through-hole through the metal plate and the resin-based fiber composite material along the thickness of the leaf spring body. A through-hole positioning hole is also provided in the center of the leaf spring body. This through-hole positioning hole creates a through-hole through the metal plate and the resin-based fiber composite material along the thickness of the center of the leaf spring body. The leaf spring body is fixedly connected to the metal ears at each end with at least one through-bolt. A central bolt hole is used in the center of the leaf spring body for positioning and connection to the axle.

[0067] The composite leaf spring body created by the present invention includes a metal plate embedded in the leaf spring resin-based fiber composite material. The through-hole bolts pass through the composite material through the metal plate. After the leaf spring is installed, the lateral force and longitudinal force transmitted by the frame can be well dispersed on the metal plate, thereby reducing the longitudinal force and lateral force of the through-hole bolts on the composite material and improving the service life of the composite leaf spring.

[0068] Optionally, in some embodiments, the upper and lower metal plates at both ends of the leaf spring body may further include multiple metal plates, which are embedded in the resin-based fiber composite material. The metal plates between the upper and / or lower sides of the central area of ​​the leaf spring body may further include multiple metal plates, which are embedded in the leaf spring body. Figure 7 When the leaf spring body is secured at both ends with through-hole bolts and coiled ears, the longitudinal and / or lateral forces generated during frame movement are better distributed across the multiple metal sheets, thereby reducing damage to the resin-based fiber composite material caused by the through-hole bolts. When the leaf spring's center portion is positioned and secured to the axle with a through-hole center bolt, the longitudinal and / or lateral forces generated during frame movement are better distributed across the multiple metal sheets in the center of the leaf spring, thereby reducing damage to the resin-based fiber composite material caused by the through-hole bolts.

[0069] It should be understood that the multiple metal plates at the ends of the leaf spring body and the multiple metal plates in the middle region of the leaf spring can be implemented independently of each other. For example, in actual use, the ends of the leaf spring can include multiple metal plates, while the center region can include only the lower metal plate or the upper metal plate. It should also be understood that the thickness of the metal plates between the upper and lower metal plates at the ends and the middle of the leaf spring body can be different from the thickness of the upper and lower metal plates. In a preferred embodiment, the thickness of the multiple metal plates between the upper and lower metal plates of the leaf spring body is less than the thickness of the upper and lower metal plates.

[0070] Figure 8 、 Figure 9 A schematic diagram illustrates the forces acting on the leaf spring body during vehicle frame motion. During vehicle motion, due to starting, steering, or braking, the frame's inertia generates longitudinal and / or lateral forces on the leaf spring body through the coil ears and through-hole bolts. The leaf spring assembly structure of the present invention effectively distributes these lateral and longitudinal forces generated during vehicle movement across the metal sheet, thereby reducing the force exerted by the through-hole bolts on the resin-based fiber composite material and extending the service life of the resin-based fiber composite material leaf spring.

[0071] Optionally, in some embodiments, the side surfaces of the central area of ​​the leaf spring body respectively include metal plates, the metal plates are embedded in the leaf spring body, and the metal plates include at least one rectangular parallelepiped protrusion. Figure 10a A top view of the middle area of ​​the leaf spring body is shown. Figure 10a As shown, the middle part of the leaf spring body includes metal plates 4a and 4b on both sides, which are embedded in the leaf spring body during the forming process of the composite leaf spring. The lateral metal plates respectively include two rectangular protrusions, which are used to cooperate with the U-shaped grooves on the side of the U-shaped metal cover, so that the U-shaped metal cover plate is locked with the leaf spring body along the length direction of the leaf spring without relative movement. Figure 10bA top view of a U-shaped metal cover is shown. The cover includes a U-shaped groove that mates with the protrusion on the metal plate on the side of the leaf spring body in this embodiment. The bottom of the U-shaped cover also includes a positioning hole that mates with the positioning pin in the axle, thereby positioning and assembling the U-shaped metal cover to the axle. It should be understood that the bottom of the U-shaped metal cover may also include a metal positioning protrusion, and the upper positioning hole of the axle to achieve the positioning and assembly of the leaf spring and the axle. It should also be understood that the metal plate protrusion on the side of the central area of ​​the leaf spring body can include various forms. For example, the protrusion can be semi-cylindrical, and the corresponding groove on the metal cover is semi-circular to mate with the semi-cylindrical protrusion on the metal plate.

[0072] Optionally, in some embodiments, the metal plate on the side of the central region of the leaf spring body may not include a rectangular protrusion, and the surface of the side metal plate that is not in contact with the resin-based fiber material is higher than the surface of the resin-based fiber material. This allows the metal plate itself to serve as a positioning protrusion, thereby cooperating with the metal cover plate for positioning and fixing. In this case, the two protruding side surfaces of the side metal plate in the middle region of the leaf spring body along the length direction of the leaf spring match the front and rear baffles at both ends of the metal cover plate, thereby achieving a locking of the metal cover plate and the leaf spring body without relative movement. It should be understood that in this embodiment, the side metal plate and the metal cover plate can be matched in various ways. When the metal plate itself serves as a positioning protrusion, it can also include a rectangular positioning protrusion. In this case, the matching metal cover plate not only includes a groove that matches the rectangular protrusion, but also includes front and rear baffles that match the metal plate. The front and rear baffles contact the two side surfaces of the metal plate along the length direction of the leaf spring.

[0073] It should be understood that when the side of the leaf spring includes a metal plate, the protrusion that matches the metal plate and the metal cover plate can be the metal plate itself. At this time, the surface of the metal plate that is not in contact with the resin-based fiber material has a significant height difference relative to the surface of the resin-based fiber material. This height difference can serve as a positioning protrusion, that is, the surface of the metal plate that is not in contact with the resin-based fiber material is higher than the surface of the resin-based fiber material.

[0074] Optionally, in some embodiments, the metal plates respectively included on the upper and lower surfaces at both ends of the leaf spring body, the metal plates included on the upper and / or lower surfaces of the central region of the leaf spring body, or the metal plates respectively included on the side surfaces of the central region of the leaf spring body facing the resin-based fiber composite material have concave-convex surfaces. Specifically, the surfaces of the upper and lower metal plates at both ends of the leaf spring body that contact the composite material have convex structures, and the convex structures can be cones, such as Figure 11a 、 11b As shown, Figure 11a A schematic diagram showing a front view of a metal plate, Figure 11bA schematic diagram of a top view of a metal plate is shown. When the contact surface between the metal plate and the composite leaf spring is a conical protrusion structure, the contact area between the metal plate and the resin-based fiber composite material can be increased during the leaf spring body forming process, thereby increasing the adhesion effect between the metal plate and the resin-based fiber composite material. On the other hand, the protrusion structure on the surface of the metal plate can further enhance the interaction between the fiber material in the resin-based fiber composite material and the metal plate, thereby enhancing the interaction force between the metal plate and the resin-based fiber composite material, so that the metal plate can withstand greater longitudinal and lateral forces. It should be understood that the protrusion structure can include various types, such as triangular pyramids, quadrangular pyramids, etc.

[0075] Optionally, in some embodiments, the metal plate can also be chemically treated so that the metal plate and the resin can be more firmly bonded. For example, in the process of forming a resin-based fiber composite leaf spring, the metal plate is immersed in a silane coupling agent so that the silane coupling agent adheres to the metal surface, and then the metal plate is molded with the resin and fiber. The silane coupling agent can increase the bonding force between the metal surface and the resin, thereby making the metal plate and the resin-based fiber composite material more firmly bonded. It should be understood that those skilled in the art can also chemically treat the metal surface in other ways to make the metal and resin bond more firmly, such as performing an anodic polarization treatment on the metal plate to change the strength of the bonding between the metal surface and the resin base.

[0076] Optionally, in some embodiments, the metal plate may be treated by a combination of physical and chemical methods. For example, shot peening may be used to create a concave-convex surface on the metal surface to increase the bonding area between the metal surface and the resin, while the metal may be soaked in a silane coupling agent before being molded with the resin fiber.

[0077] Several embodiments of the present invention are described in detail below.

[0078] Example 1:

[0079] Figure 3 and Figure 4 A resin-based fiber composite leaf spring assembly is shown. The assembly comprises a composite leaf spring body, metal ears, and fastening bolts. The composite leaf spring body comprises upper and lower metal plates 1a and 1b at each end, respectively. These plates are embedded within the resin-based fiber composite material and have two bolt holes, each slightly less deep than the thickness of the plates. The composite leaf spring body also comprises upper and lower metal plates embedded within the resin-based fiber composite material. The metal plate below the central portion includes a locating hole, slightly less deep than the thickness of the plate, for assembly with locating bolts on the axle.

[0080] In this embodiment, the surfaces of the metal plates at both ends of the leaf spring body and the metal plate in the middle area of ​​the leaf spring body facing the composite material may be conical protrusions, such as Figure 11a 、 11b The metal plate shown in the figure has a barbed cone in contact with the leaf spring resin-based fiber composite material. The cone has a height of 0.5 mm to 5 mm and a taper of 0.3 to 10.

[0081] The metal plates at each end of the leaf spring body are each provided with two bolt holes, which mate with the bolt holes in the U-shaped metal plates of the metal ears. Fastening bolts secure the metal ears to the leaf spring body. While the present invention utilizes only two bolt holes at each end of the leaf spring body as a specific embodiment, the invention is not limited to this. Those skilled in the art may also employ various numbers of bolt holes for fastening, and the present invention is not limited thereto. In this embodiment, φ12 bolts are used to secure the metal ears to the leaf spring body, but this is not a limitation of the present invention.

[0082] In an embodiment, the thickness of the metal plates at both ends of the leaf spring body can be 0.1mm-20mm, and the length along the leaf spring direction can be 20mm-200mm; the thickness of the upper and lower metal plates in the middle part can be: 0.1mm-15mm.

[0083] Figure 12 A metal ear structure is shown. The two inner end faces of the U-shaped metal plate form a circular transition. During assembly, if the U-shaped metal ear is in contact with the metal plates at both ends of the leaf spring body, the metal plates will generate significant resistance during assembly. However, the circular transition of the ear can effectively reduce the difficulty of the transition between the ear and the leaf spring body and improve the efficiency of the transition.

[0084] When the leaf spring assembly is transferred to the frame, the following steps are used to assemble the assembly:

[0085] Insert either end of the leaf spring body between the U-shaped metal plates of the metal ears, and securely connect the metal ears to the leaf spring body with fastening bolts;

[0086] Stack the axle, the leaf spring body with metal ears, and the metal clamping plate on the U-bolt from bottom to top. The positioning hole of the lower metal plate in the middle of the metal leaf spring matches the positioning bolt on the axle. Install the U-bolt and clamp and fix the leaf spring and the axle with the U-bolt. The metal clamping plate on the U-bolt is the metal plate placed on the leaf spring body when the U-bolt is fixed to the leaf spring body.

[0087] Assemble the leaf spring assembly ears at the frame leaf spring connection points or intersections to complete the installation of the composite leaf spring assembly.

[0088] In this embodiment, the middle part of the leaf spring body may only include a lower metal plate. During the assembly process, a rubber pad may be included between the upper metal clamping plate of the U-bolt and the leaf spring body, thereby reducing the friction between the upper metal clamping plate and the composite material of the leaf spring body and improving the service life of the leaf spring.

[0089] Example 2

[0090] Figure 8 A composite leaf spring assembly structure is shown. The composite leaf spring comprises a composite leaf spring body, metal ears, and through-hole fastening bolts. The composite leaf spring body comprises three metal plates at each end, embedded within a resin-based fiber composite material. The metal plates are provided with through-hole bolt holes forming the vertices of an equilateral triangle. The composite leaf spring body also comprises three metal plates in the middle, embedded within the resin-based fiber composite material. These metal plates include through-hole bolt holes that mate with the axle center bolts for positioning and assembly.

[0091] In this embodiment, the metal plate structure in the leaf spring body can be the same as that in Example 1, or it can be modified on the basis of Example 1. For example, the upper and lower metal plates at both ends of the leaf spring can adopt barbed conical metal plates, and the metal plate between the upper and lower metal plates can adopt smooth metal plates, or all of them can adopt metal plates with barbed conical surfaces. A person skilled in the art can come up with a variety of combination schemes for this, and the invention will not be repeated here.

[0092] In this embodiment, the through-hole fastening bolts connecting the two ends of the leaf spring body to the coil ears can also adopt the same double-through-hole arrangement as in Example 1, which will not be described in detail in this example.

[0093] In this embodiment, the size of the metal plate in the leaf spring body may be the same as that in embodiment 1, which will not be described in detail in this embodiment.

[0094] In this embodiment, the through-bolt holes at both ends and the middle of the leaf spring body can be matched with φ12mm bolts for fastening connection.

[0095] It should be understood that the technical solution in this embodiment may also adopt a leaf spring body with more or fewer metal plates embedded in the structure, which will not be described in detail in the present invention.

[0096] It should also be understood that in the technical solution of this embodiment, the leaf spring body can also simply adopt an embedded structure of upper and lower layers of metal plates, which will not be described in detail in the present invention.

[0097] It should also be understood that the thickness of the upper and lower metal plates at both ends of the leaf spring body and the metal plates between them may be different, and the thickness of the upper and lower metal plates in the middle area of ​​the leaf spring body and the metal plates between them may also be different.

[0098] It should also be understood that in the technical solution of this embodiment, the end surface of the U-shaped metal plate of the ear that contacts the leaf spring body can be an arc transition.

[0099] When the leaf spring assembly is transferred to the frame, the following steps are used to assemble the assembly:

[0100] Insert the two ends of the leaf spring body between the U-shaped metal plates of the metal ears, and fix the metal ears to the leaf spring body with through-hole bolts;

[0101] Place the axle, the leaf spring body with metal ears, and the metal clamping plate on the U-bolt from bottom to top. The middle part of the metal leaf spring is assembled with the axle through the perforated center bolt. Install the U-bolt and clamp and fix the leaf spring and the axle with the U-bolt.

[0102] Assemble the leaf spring assembly ears at the frame leaf spring connection points or intersections to complete the installation of the composite leaf spring assembly.

[0103] Example 3

[0104] Figure 13 A composite leaf spring assembly is shown. The assembly includes a composite leaf spring body, metal ears, perforated fastening bolts, rubber pads, and a U-shaped metal cover. The U-shaped metal cover has U-shaped grooves on both sides and positioning holes at the bottom. The composite leaf spring body comprises upper and lower metal plates at each end, embedded in a resin-based fiber composite material. The metal plates are provided with perforated bolt holes forming equilateral triangle vertices. The composite leaf spring body also comprises metal plates on both sides of the middle portion, embedded in the resin-based fiber composite material. The metal plates include rectangular protrusions that mate with the U-shaped grooves of the U-shaped metal cover. The positioning holes at the bottom of the U-shaped metal cover mate with the locating pins of the axle.

[0105] In this embodiment, the surface of the metal plate in the leaf spring body can be the same as that in Example 1, or it can be modified on the basis of Example 1. For example, the upper and lower metal plates at both ends of the leaf spring can adopt barbed conical metal plates, and the metal plate between the upper and lower metal plates can adopt smooth metal plates. Those skilled in the art can come up with a variety of combination schemes for this, which will not be elaborated in the present invention.

[0106] In this embodiment, the through-hole fastening bolts connecting the two ends of the leaf spring body to the coiled ears can also be arranged in a regular triangle vertex arrangement, which will not be described in detail in this embodiment.

[0107] In this embodiment, the sizes of the metal plates at both ends of the leaf spring body can be the same as those in embodiment 1.

[0108] It should be understood that in the technical solution of this embodiment, the metal plates at both ends of the leaf spring and the ears can adopt the non-perforated fastening bolt fixing structure in Example 1, or the perforated fastening structure in Example 2.

[0109] It should also be understood that in the technical solution of this embodiment, the positioning hole at the bottom of the U-shaped cover plate in the middle of the leaf spring body can pass through the bottom of the U-shaped metal cover plate and penetrate the entire leaf spring body. In this solution, the leaf spring body and the axle can be fixed together by a perforated center bolt.

[0110] It should also be understood that in the technical solution of this embodiment, the end surface of the U-shaped metal plate of the ear that contacts the leaf spring body can be an arc transition.

[0111] When assembling the leaf spring assembly to the frame, use the following steps to assemble the assembly:

[0112] Insert the two ends of the leaf spring body between the U-shaped metal plates of the metal ears, and fix the metal ears to the leaf spring body with through-hole bolts;

[0113] Stack the axle, U-shaped metal cover, leaf spring body, rubber pad, and metal clamping plate on the U-shaped bolt from bottom to top. The metal plate protrusions on both sides of the middle of the metal leaf spring match the U-shaped grooves of the U-shaped metal cover. The positioning holes at the bottom of the U-shaped metal cover match the axle point pins. Install the U-bolts and clamp and fix the leaf spring and axle with the U-shaped bolts.

[0114] Assemble the leaf spring assembly ears at the frame leaf spring connection points or hinge points to complete the installation of the composite leaf spring assembly.

[0115] The following describes the method for manufacturing the leaf spring body of the present invention. The leaf spring body of the present invention is manufactured using a high pressure resin transfer molding (HP-RTM) method.

[0116] The specific steps are as follows:

[0117] 1. Dry the formed glass fiber;

[0118] In this step, the raw glass fiber is dried in a drying oven at 150°C to remove moisture from the glass fiber. In the present invention, glass fiber is used as the reinforcement material of the resin-based fiber material, but the present invention is not limited to this. Other reinforcing fibers such as carbon fiber can also be used. The drying method can also be selected from air drying or other methods according to the specific material properties. Of course, this drying step can also be omitted depending on the material conditions.

[0119] 2. Arrange the glass fibers according to a preset path to preform the glass fibers;

[0120] In this step, the glass fibers are arranged according to the shape of the designed leaf spring to form a glass fiber leaf spring preform.

[0121] 3. Place the glass fiber preform in step 2 in a mold with a matching shape. The mold has grooves at both ends and in the middle for placing the metal plate. The grooves match the shape of the metal plate and the depth of the grooves is less than or equal to the thickness of the metal plate.

[0122] In this step, the molding machine applies pressure to the preform through the mold. For leaf springs with metal plates at both ends and in the middle, the mold is provided with grooves for the metal plates. In some embodiments, the side surfaces of the mold may also have grooves, with the depth of the grooves being less than or equal to the thickness of the metal plates.

[0123] 4. Inject resin into the mold in step 3 under high pressure while applying pressure to the preform;

[0124] 5. Demould and complete the leaf spring body.

[0125] For a leaf spring body having multiple layers of metal plates at both ends and in the middle, the present invention also provides a method for manufacturing a composite leaf spring body, specifically comprising:

[0126] 1. Dry the formed glass fiber;

[0127] In this step, the raw glass fiber is dried in a drying oven at 150°C to remove moisture from the glass fiber. In the present invention, glass fiber is used as the reinforcement material of the resin-based fiber material, but the present invention is not limited to this. Other reinforcing fibers such as carbon fiber can also be used. The drying method can also be selected from air drying or other methods according to the specific material properties. Of course, this drying step can also be omitted depending on the material conditions.

[0128] 2. Arrange the glass fibers according to a preset path to preform the glass fibers;

[0129] In this step, the glass fibers are arranged in layers according to the shape of the designed leaf spring. Depending on the thickness of the arrangement, when a metal plate needs to be added, after completing the arrangement of the previous layer of fibers, the middle layer of metal plates is placed on the glass fibers, and then the next layer of fibers is arranged. This process is repeated until the metal plates need to be placed again. The number of metal plates to be placed is determined according to the design requirements, and then the preform is completed. The two ends and the middle area of ​​the preform may include multiple metal plates.

[0130] 3. Place the glass fiber preform in step 2 in a mold with a matching shape. The mold has grooves at both ends and in the middle for placing the metal plate. The grooves match the shape of the metal plate and the depth of the grooves is less than or equal to the thickness of the metal plate.

[0131] In this step, a molding machine applies pressure to the preform through the die. For leaf springs with metal plates at both ends and above and below the center of the spring body, grooves are provided at both ends and above and below the die to accommodate the metal plates. The depth of these grooves should be less than or equal to the thickness of the metal plates. The metal plates added in this step are the metal plates on the surface of the leaf spring body. The thickness of these metal plates can be the same as or different from that in step 2.

[0132] 4. Inject resin into the mold in step 3 under high pressure while applying pressure to the preform;

[0133] 5. Demould and complete the leaf spring body.

[0134] The present invention proposes a method for manufacturing a leaf spring body. There are many different methods for forming resin-based fiber composite leaf springs. Those skilled in the art can combine the inspiration of the present invention to obtain a variety of different leaf spring body manufacturing methods, and the present invention does not limit this.

[0135] The leaf spring body, composite leaf spring, and composite leaf spring body described in the specification of the present invention all refer to a resin-based fiber composite leaf spring body.

[0136] As previously noted, the various specific embodiments of the present invention are not limited to the above description. For example, based on the specific teachings of the embodiments of the present invention, those skilled in the art may also develop a leaf spring body having a central portion comprising four metal plates, one above, one below, and one on each side. Based on this, further specific embodiments may be obtained by combining the number of metal plates at both ends of the leaf spring body and whether the metal plates are fixedly connected with holes or non-holes. Therefore, although the present invention has been specifically shown and described with reference to preferred embodiments, it should be understood that those skilled in the art may derive further technical solutions by varying the form and details, or that any changes or substitutions readily conceivable by those skilled in the art within the technical scope disclosed in this application are intended to be covered by the scope of protection of this application.

Claims

1. A resin-based fiber composite leaf spring body, wherein the leaf spring body has a parabolic structure, wherein the concave parabola is the upper surface of the leaf spring body, the convex parabola is the lower surface of the leaf spring body, and the surfaces adjacent to the upper surface and the lower surface are side surfaces of the leaf spring body, characterized in that: The upper and lower surfaces of both ends of the leaf spring body respectively include metal plates, and the metal plates are embedded in the leaf spring body; The leaf spring body includes a protrusion below the middle portion, and a metal plate matching the protrusion is assembled below the protrusion. The metal plate is embedded in the leaf spring body, and a groove formed by the metal plate tightly fixes the protrusion of the leaf spring body. The front-rear longitudinal force generated during vehicle driving is transmitted through the protrusion on the leaf spring body, thereby reducing the wear of the leaf spring body by the axle and avoiding damage to the leaf spring body caused by drilling holes in the leaf spring body. The bottom of the metal plate also includes a positioning pin, which matches the positioning hole in the axle. The positioning pin and the positioning hole cooperate with each other to achieve the positioning installation of the leaf spring body and the axle; The metal plates at both ends of the leaf spring body are provided with at least one bolt hole, and the depth of the bolt hole is less than or equal to the thickness of the metal plate; The upper and lower parts of the central area of ​​the leaf spring body include metal plates, the metal plates are embedded in the leaf spring body, and the lower metal plate includes at least one positioning hole, the depth of the positioning hole is less than or equal to the thickness of the metal plate; The upper and lower metal plates at both ends of the leaf spring body each comprise a plurality of metal plates, wherein the metal plates are embedded in a resin-based fiber composite material, and the metal plates between the upper and lower sides of the central region of the leaf spring body comprise a plurality of metal plates; wherein the metal plates are further embedded between the multiple layers of fibers of the leaf spring body; The metal plates respectively included on the upper and lower sides of the two ends of the leaf spring body, the metal plates respectively included on the upper and lower sides of the central area of ​​the leaf spring body, and the metal plates respectively included on the side surfaces of the central area of ​​the leaf spring body facing the resin-based fiber composite material are concave and convex contact surfaces.

2. The leaf spring body according to claim 1, wherein: The metal plates respectively included on the upper and lower sides of the two ends of the leaf spring body, the metal plates included on the upper and / or lower sides of the central area of ​​the leaf spring body, or the metal plates respectively included on the sides of the central area of ​​the leaf spring body have a length of 20mm-200mm along the length direction of the leaf spring body, and a thickness along the thickness direction of the leaf spring body of 0.1mm-80mm.

3. The leaf spring body according to claim 1, wherein: The metal surfaces of the metal plates respectively included on the upper and lower sides of the two ends of the leaf spring body, the metal plates included on the upper and / or lower sides of the central area of ​​the leaf spring body, or the metal surfaces of the metal plates respectively included on the sides of the central area of ​​the leaf spring body facing the resin-based fiber composite material are chemically modified to obtain a metal modified surface.

4. The leaf spring body according to claim 3, wherein: The metal surfaces of the metal plates respectively included on the upper and lower sides of the two ends of the leaf spring body, the metal plates included on the upper and / or lower sides of the central area of ​​the leaf spring body, or the metal plates respectively included on the side surfaces of the central area of ​​the leaf spring body facing the resin-based fiber composite material are chemically modified to obtain the metal modified surface, including: coating a silane coupling agent on the metal surface to obtain the metal modified surface.

5. The leaf spring body according to claim 1, wherein: The concave-convex contact surface of the metal plate includes conical protrusions or polygonal conical protrusions on the surface of the metal plate.

6. A resin-based fiber composite leaf spring assembly, characterized in that: It comprises the leaf spring body, metal ear and fastening bolt according to any one of claims 3 to 5, the metal ear comprises a frame hinge tube and a leaf spring clamping plate, the leaf spring clamping plate and the frame hinge tube form a U-shaped structure, and the leaf spring clamping plate of the metal ear is fixedly connected to the leaf spring body by a fastening bolt.

7. A resin-based fiber composite leaf spring assembly, characterized in that: It includes the leaf spring body, metal ear, fastening bolts, and U-shaped metal cover according to any one of claims 3 to 5, the metal ear includes a frame hinge tube and a leaf spring clamping plate, the leaf spring clamping plate and the frame hinge tube form a U-shaped structure, the leaf spring clamping plate of the metal ear is fixedly connected to the leaf spring body by fastening bolts, and the U-shaped metal cover includes at least one U-shaped groove, and the U-shaped groove matches the rectangular protrusion of the metal plate on the side of the central area.

8. A method for manufacturing the leaf spring body according to any one of claims 1 to 5, characterized in that: include: 1) Drying the glass fiber to be formed; 2) Arranging the glass fibers according to a preset path to preform the glass fibers; 3) The fiberglass preform from step 2 is placed in a mold of a matching shape. The mold has grooves at both ends and in the middle for placing the metal plate. The grooves match the shape of the metal plate and the depth of the grooves is less than or equal to the thickness of the metal plate. 4) Injecting resin into the mold in step 3 under high pressure while applying pressure to the preform; 5) Demolding to complete the leaf spring body.

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