Compression spring based on an array of periodic structural members of fiber composite material and use thereof

Abstract

The present application relates to a kind of compression spring based on fiber composite periodic structure component array and its application.The compression spring includes upper cover, lower cover and several periodic structure components, the periodic structure components are dispersed and fixed between upper and lower cover in annular or multi-row multi-column array form, to bear bending load.The periodic structure components are integrally formed by carbon fiber composite material or glass fiber composite material, and the shape is continuous positive and negative bending long strip shape, this design not only realizes the lightweight of spring, but also improves the performance and service life of spring, so that it can be applied to automobile suspension spring and other vibration isolation fields.In addition, the stiffness of the periodic structure component is proportional to the modulus of fiber length direction, thereby solving the low stiffness problem of composite material spiral compression spring.In the process level, the periodic structure component is prepared by molding process using mold and autoclave, whether mold structure or preparation process is relatively simple.

Description

Technical Field

[0001] This invention relates to the fields of vibration reduction and isolation and automotive parts technology, specifically to a compression spring based on a periodic structural component array of fiber composite materials and its application. Background Technology

[0002] Commonly used vibration damping and isolation springs on the market include Figure 1 As shown, while this type of metal helical compression spring has many advantages, it also has some disadvantages, such as its heavy weight and susceptibility to corrosion from water and oxygen. Furthermore, during long-term use, the compression spring undergoes cyclic loading and unloading, causing microscopic defects in the metal material to gradually expand and eventually form cracks, leading to fatigue failure.

[0003] To address this, some researchers have attempted to replace traditional metal materials with composite materials, using metal molds and a winding process to manufacture composite helical compression springs. However, this approach suffers from the following problems: ① Metal molds are complex to manufacture and costly; ② The winding angle is difficult to control during the winding process, easily leading to twisting and wrinkling, resulting in inconsistent molding quality; ③ Under the same structural dimensions, the stiffness of a composite helical compression spring is inevitably less than that of a metal helical compression spring. This is because when a helical compression spring is under compression, the spring wire primarily bears torsional loads, and the stiffness of the helical compression spring (stiffness calculation formula below) is positively correlated with the material's shear modulus G.

[0004]

[0005] Taking T700 grade carbon fiber composite material as an example, its shear modulus is about 5000 MPa, while that of metal materials is about 79000 MPa. The shear modulus of composite materials differs from that of metal materials by more than 10 times. Therefore, the performance of existing composite material helical compression springs is far inferior to that of metal helical compression springs. Summary of the Invention

[0006] The purpose of this invention is to overcome the aforementioned problems commonly found in existing metal and composite material helical compression springs, and to provide a compression spring based on a periodic structural component array of fiber composite materials. By introducing low-density, high-damping fiber composite materials such as glass fiber and carbon fiber, not only is the spring lightweight achieved, but the problems of complex spring manufacturing processes and high costs are also effectively solved, and the fatigue life of the fiber composite material compression spring is significantly improved. To achieve the above objectives and effects, the technical solution adopted by this invention is as follows:

[0007] A compression spring includes an upper cover 2, a periodic structural member 4, and a lower cover 5. The upper and lower ends of the periodic structural member 4 are fixedly connected to the upper cover 2 and the lower cover 5, respectively, and bear bending loads.

[0008] Specifically, the periodic structural member 4 is formed by bending glass fiber composite material, carbon fiber composite material, etc., in both directions along the fiber length direction and the compression spring length direction.

[0009] Specifically, each periodic structural component 4 consists of at least one set of repeating periodic units. When there are two or more sets of periodic units, the different periodic units are arranged alternately in a cyclical manner.

[0010] Specifically, the number of the periodic structural components 4 is not less than 2, and they are distributed between the upper cover 2 and the lower cover 5.

[0011] More specifically, the number of periodic structural components 4 is 2-16, and the arrangement of these periodic structural components 4 includes circular or circular arrays, rectangular or rectangular arrays (multi-row and multi-column), triangular or triangular arrays, etc.

[0012] Specifically, the upper cover 2 and the lower cover 5 are both made of metal and have the same shape, such as rectangle, ring, circle or triangle.

[0013] Specifically, the connection and fixing method between the periodic structural component 4 and the upper cover 2 and the lower cover 5 is selected from at least one of adhesive bonding, welding, and bolt connection, with bolt connection being preferred.

[0014] More specifically, through holes are provided at both the upper and lower ends of the periodic structure component 4, and matching positioning grooves are provided on the upper cover 2 and the lower cover 5, with connecting holes in the positioning grooves. During assembly, the two ends of the periodic structure component 4 are aligned with the positioning grooves, and then the bolts are passed through the connecting holes and through holes and tightened with nuts, thereby fixing the periodic structure component 4 together with the upper cover 2 and the lower cover 5.

[0015] More specifically, I-shaped metal bushings are pre-embedded at both ends of the periodic structural component 4, and the through holes are located in the metal bushings. The I-shaped structure of the metal bushings ensures a reliable connection with the periodic structural component made of fiber composite material, avoiding the impact of secondary machining of the through holes on the mechanical properties of the integrally formed periodic structural component.

[0016] The compression spring provided by this invention can effectively replace existing metal coil springs, such as automotive suspension springs, control springs in clutches, buffer springs in rail trains, and vibration-absorbing springs in couplings.

[0017] Compared with existing similar products, the advantages of this invention are mainly reflected in the following aspects: (1) The core component of the compression spring, the periodic structure component, is made of fiber composite material with low density and high damping characteristics, which not only achieves the weight reduction of the spring, but also improves the performance and service life of the spring; (2) The fiber composite material is laid flat and repeatedly bent in both directions to form the periodic structure component, which ensures that the stiffness of the compression spring is positively correlated with the modulus of the fiber direction of the composite material, so that it can withstand a large bending load; (3) The periodic structure component is prepared by molding process of mold + autoclave, which makes the mold structure and preparation process relatively simple, effectively solving the problems of complex preparation process and high cost that are common in current helical compression springs; (4) Several periodic structure components in the compression spring of this invention are arranged in a certain way, and the symmetrical array arrangement greatly improves the stability of the compression spring and avoids problems such as tilting and instability. Attached Figure Description

[0018] Figure 1 A three-dimensional schematic diagram of a traditional metal or composite material helical compression spring;

[0019] Figure 2 A three-dimensional schematic diagram of the compression spring provided by the present invention;

[0020] Figure 3 for Figure 2 The diagram shows an explosion of a compression spring.

[0021] Figure 4 A three-dimensional schematic diagram of a periodic structural component;

[0022] Figure 5 The images show a side view and a partially enlarged schematic diagram of a periodic structural component.

[0023] Figure 6 This is a schematic diagram of the forces acting on a periodic structural member.

[0024] Figure 7 A three-dimensional schematic diagram of another compression spring provided by the present invention;

[0025] Figure 8 for Figure 7 The diagram shows an explosion of a compression spring.

[0026] Figure 9 A performance comparison diagram of the compression spring provided by this invention and a traditional metal helical compression spring.

[0027] Wherein: 1-screw, 2-upper cover, 3-metal bushing, 4-periodic structural component, 5-lower cover, 6-nut, 7-positioning groove, 8-periodic unit I, 9-periodic unit II. Detailed Implementation

[0028] To enable those skilled in the art to fully understand the technical solution and beneficial effects of the present invention, the following description is provided in conjunction with specific embodiments and accompanying drawings.

[0029] Commonly used springs on the market include Figure 1 As shown, helical compression springs are typically made of metal or composite materials. Metal helical compression springs suffer from problems such as high weight and susceptibility to fatigue fracture, while composite material helical compression springs suffer from lower modulus and strength in specific directions, complex manufacturing processes, and unstable molding quality. To address these issues, the inventors' team developed a compression spring based on a periodic structural component array of fiber composite materials. This spring exhibits superior mechanical properties and service life, effectively replacing traditional metal helical compression springs while avoiding all the aforementioned problems.

[0030] Example 1

[0031] like Figure 2-3 The compression spring shown is based on an array of periodic structural components made of fiber composite materials. It includes an upper cover 2, several periodic structural components 4, a lower cover 5, and several sets of connecting fasteners. These periodic structural components 4 are distributed vertically, and the top and bottom of each periodic structural component 4 are fixedly connected to the upper cover 2 and the lower cover 5 respectively by at least one set of connecting fasteners. In some cases, the opposing surfaces of two workpieces can be used as the upper and lower covers, and the periodic structural components can be directly fixed between the two workpieces in a certain manner.

[0032] The top cover 2 and the bottom cover 5 usually appear in pairs. They are usually the same size and shape, and are made of metal (such as stainless steel). They can be mass-produced by stamping. Figure 2-3 The upper cover 2 and lower cover 5 are circular, with four identical periodic structural components 4 arranged symmetrically in pairs between them. Of course, the upper cover 2 and lower cover 5 can also be other shapes, such as triangles, circles, or rectangles. In this case, the number and arrangement of the periodic structural components 4 need to be adjusted to evenly distribute the external pressure or tension acting on the spring. Positioning grooves 7 are symmetrically arranged along the circumference on the lower surface of the upper cover 2 and the upper surface of the lower cover 5. Each positioning groove 7 contains two through screw holes. The number of positioning grooves is the same as the number of periodic structural components 4, mainly used for positioning when the two are connected. The number of screw holes is twice the number of periodic structural components 4, mainly used for fixing the connection after positioning.

[0033] The periodic structural component 4 is made of carbon fiber composite material or glass fiber composite material. During production, the carbon fiber composite material or glass fiber composite material is laid flat on a corrugated mold, ensuring the fiber length direction aligns with the mold's length direction. The mold is then placed in an autoclave for hot pressing, resulting in the continuously bending periodic structural component 4, with a shape resembling... Figure 4 As shown. The periodic structural component 4 is composed of a series of periodic units arranged in a repetitive manner. Each periodic structural component 4 may contain one periodic unit ( Figure 4 The periodic unit I shown in the left figure can also contain multiple periodic units ( Figure 4 The right figure shows periodic unit I and periodic unit II. In the latter case, different periodic units are usually arranged alternately in a cycle. Periodic units can be classified into different models according to their structural form and size. Figure 4 The left side shows periodic unit I with a uniform width structure. Figure 4 The right side shows periodic unit I with an outwardly convex structure and periodic unit II with an inwardly concave structure.

[0034] To avoid damaging the integrally molded periodic structural component 4, its connection parts were carefully optimized. For example... Figure 5 As shown, I-shaped metal bushings 3 are pre-embedded on the upper and lower end faces of the periodic structure component 4. During assembly, first align the upper and lower ends of the periodic structure component 4 with the positioning grooves 7 of the upper cover 2 and the lower cover 5, then insert screws or bolts from the outside into the screw holes on the upper cover 2 and the lower cover 5 and the I-shaped metal bushings 3, and finally connect and lock them with nuts 6.

[0035] Example 2

[0036] Another type of compression spring based on a periodic structural component array of fiber composite materials provided by this invention is as follows: Figure 7-8 As shown, its structure is the same as the compression spring in Example 1, except that the upper and lower covers are changed from rings to rectangular plates, and the arrangement of the periodic structural components is changed from a ring to a matrix of multiple rows and columns (2*4).

[0037] like Figure 6 As shown, a stress analysis of the periodic structural member 4 provided by this invention reveals that it primarily bears bending moments. The displacement Δ of the periodic structural member 4 under load P can be calculated using the following formula. A M and Let P and the bending moment under a unit load be respectively, T be the number of periodic elements, and E be the elastic modulus of the composite material in the fiber direction.

[0038]

[0039] Substituting the above formula into the formula below, we can obtain the stiffness of the periodic structural member 4. Analysis of the above formula shows that the stiffness of the periodic structural member 4 is positively correlated with the modulus in the fiber direction of the composite material. Taking T700 grade carbon fiber composite material as an example, its modulus in the fiber direction is approximately 150,000 MPa, corresponding to a relatively high stiffness in the periodic structural member 4. This effectively solves the problem of low stiffness commonly found in fiber-reinforced composite helical compression springs.

[0040] To fully understand the performance differences between the compression spring based on a periodic structural component array of fiber composite materials provided by this invention and the traditional metal helical compression spring, the following comparative experiments were conducted:

[0041] A periodic structural member 4 with a height H = 154 mm, length L = 64 mm, width W = 34 mm, and thickness t = 4 mm was fabricated using glass fiber composite materials. Figure 4 (as shown), refer to Figure 4 A compression spring sample was prepared. (Refer to...) Figure 1 The structure shown is a stainless steel compression spring sample with a height of 154 mm, a major diameter of 35 mm, and a wire diameter of 5 mm. The compression performance of two types of springs was tested according to GB / T23935-2009. The specific test procedure is as follows:

[0042] Different spring samples were mounted on the support base of the electronic universal testing machine. The test program of the electronic universal testing machine was set, and the test method was selected as compression test. The loading rate of the lower indenter of the electronic universal testing machine was 5 mm / min, the output variables were load and displacement, and the sampling frequency was 100 Hz. The test was completed under the condition that the output load dropped sharply or the spring showed obvious tilting. The experimental results are as follows. Figure 9 As shown.

[0043] Depend on Figure 9 As can be seen, the stiffness of the compression spring (i.e., the glass fiber composite wave spring in the figure) provided by this invention is not much different from that of the traditional metal helical spring, effectively solving the problem that the stiffness of the composite material helical spring is lower than that of the metal helical spring. Measurements show that the mass of the traditional metal helical compression spring is 198.13g, while the mass of the compression spring of this invention is 157.82g, a weight reduction of 20.35%.

[0044] By adjusting the periodic structure form, fiber type, and layup angle of the fiber composite periodic structural components, adjustments can be made for different working conditions to adapt to specific applications in different fields.

[0045] In summary, the compression spring based on a periodic structure of fiber composite material provided by this invention has excellent performance and can be used as an equivalent replacement for traditional helical compression springs. It can be applied to many vibration reduction and isolation fields such as automotive suspension springs.

Claims

1. A compression spring based on a periodic structural component of fiber composite material, characterized in that: The compression spring includes an upper cover (2), a periodic structural component (4), and a lower cover (5). The two ends of the periodic structural component (4) are fixedly connected to the upper cover (2) and the lower cover (5) respectively. The periodic structural component (4) is made of glass fiber composite material and carbon fiber composite material bent in both directions along the fiber length direction and the compression spring length direction. Each periodic structural component (4) is composed of ≥2 sets of repeating periodic units, and different types of periodic units are arranged alternately in a cycle. I-shaped metal bushings are pre-embedded at both ends of the periodic structural component (4), and through holes are provided in the metal bushings.

2. The compression spring as described in claim 1, characterized in that: The number of the periodic structural components (4) is not less than 2, and they are distributed between the upper cover (2) and the lower cover (5).

3. The compression spring as described in claim 2, characterized in that: The number of periodic structural components (4) is 2-16, and their arrangement includes circular or circular arrays, rectangular or rectangular arrays, and triangular or triangular arrays.

4. The compression spring as described in claim 1, characterized in that: The upper cover (2) and lower cover (5) are both made of metal, and their shapes include rectangle, ring, circle and triangle.

5. The compression spring as described in claim 1, characterized in that: Matching positioning grooves are provided on the upper cover (2) and lower cover (5). Connection holes are provided in the positioning grooves. The two ends of the periodic structure component (4) are aligned with the positioning grooves. After the bolts pass through the connection holes and through holes, they are connected and fixed with the nuts, thereby fixing the periodic structure component (4) together with the upper cover (2) and lower cover (5).

6. The application of the compression spring based on the periodic structural component of fiber composite material as described in any one of claims 1-5 in automobile suspension, clutch, rail train, and coupling.

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