Suspension system leaf springs and vehicles

Abstract

This invention discloses a leaf spring for a suspension system, including a leaf spring body, wherein the leaf spring body has a folded structure and is made of composite material. The leaf spring for the suspension system of this invention, made of composite material, achieves high strength and lightweight; the folded structure reduces production costs and improves process efficiency. This invention also discloses a vehicle including the aforementioned leaf spring for the suspension system.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive parts, specifically to a leaf spring for a suspension system and a vehicle. Background Technology

[0002] Suspension springs are an important component of a car's suspension system. The main functions of suspension springs are twofold: first, they bear the weight of the vehicle body, meaning that most of the vehicle's weight is typically supported by the springs; second, they mitigate road bumps. As a buffer element, when the impact force from the road surface on the wheels is transmitted to the springs, the springs deform, absorbing the kinetic energy of the wheels and converting it into the spring's potential energy, thus mitigating the impact of the road surface on the vehicle body.

[0003] Automotive chassis suspension springs primarily use metal coil springs. Although metal coil springs have been used for over a century, their structure and materials have not undergone significant changes, resulting in little performance improvement. Currently, metal coil springs mainly suffer from the following problems:

[0004] 1) High Mass. Coil springs are considered part of a car's "unsprung mass." Their mass significantly impacts the overall vehicle performance; reducing the weight of coil springs can effectively improve overall vehicle performance. Metal coil springs are relatively heavy. Coil springs are currently mainly made of rolled steel. Due to the high density of steel, steel coil springs are quite heavy. A single car typically has four coil springs, with a total mass generally between 5-15 kg.

[0005] 2) Fixed stiffness. Fixed stiffness springs maintain the same cushioning effect against various external loads, resulting in poor comfort when encountering sudden increases in load. Currently, variable stiffness air springs are too expensive (air spring bicycles cost over 1000 yuan, basically more than 20 times the price of metal springs).

[0006] Patent document CN111331877A discloses a variable stiffness composite material helical spring. However, due to its spindle-shaped structure (small at both ends and large in the middle), the central mold cannot be removed during manufacturing without destruction. Therefore, currently only disposable mandrels can be used. Removing the spring by destroying the mandrel during manufacturing leads to extremely high mold costs and low process efficiency, thus limiting the mass production and application of this variable stiffness composite material helical spring. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a leaf spring for a suspension system, with the aim of achieving lightweighting and reducing production costs.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a leaf spring for a suspension system, including a leaf spring body, wherein the leaf spring body is a folded structure and is made of composite material.

[0009] The leaf spring body includes a first spring segment, a second spring segment, and a third spring segment arranged sequentially, with the first spring segment and the third spring segment arranged symmetrically.

[0010] The thickness of the first spring segment and the third spring segment gradually decreases from one end to the other, and the end of the first spring segment and the third spring segment with the greater thickness is connected to the second spring segment.

[0011] The widths of the first spring segment and the third spring segment gradually decrease from one end to the other, and the end with the larger width of the first spring segment and the third spring segment is connected to the second spring segment.

[0012] The folding angle of the first spring segment and the third spring segment is smaller than the folding angle of the second spring segment.

[0013] The leaf spring body also includes a first connecting section connected to the first spring segment and a second connecting section connected to the third spring segment.

[0014] The suspension system leaf spring also includes two leaf spring mounting bases connected to both ends of the leaf spring body.

[0015] The leaf spring body is made of continuous fiber reinforced composite material, and the resin of the composite material is thermosetting resin or thermoplastic resin.

[0016] The leaf spring body is made of glass fiber, carbon fiber or basalt fiber.

[0017] The present invention also provides a vehicle including a leaf spring for the suspension system described above.

[0018] The suspension system leaf spring of the present invention is made of composite material, which achieves high strength and lightweight spring; the folding structure can reduce production costs and improve process efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the leaf spring used in the suspension system of this invention;

[0020] Figure 2 This is a structural schematic diagram of the leaf spring body;

[0021] Figure 3 This is a schematic diagram of the folding angle of a variable stiffness composite folded leaf spring;

[0022] Figure 4 This is a schematic diagram of the leaf spring thickness, leaf spring width, and leaf spring folding layers;

[0023] Figure 5 This is a schematic diagram showing the changes in applied force and displacement under external load;

[0024] The markings in the above figures are as follows: 1. Leaf spring mounting base; 2. Leaf spring body; 201. First spring segment; 202. Second spring segment; 203. Third spring segment; 204. First connecting segment; 205. Second connecting segment. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0026] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," and similar expressions used in this document are for illustrative purposes only.

[0027] It should be noted that in the following embodiments, the terms "first," "second," and "third" do not represent an absolute distinction in structure and / or function, nor do they represent the order of execution; they are merely for the convenience of description.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] like Figure 1 and Figure 2 As shown, the present invention provides a leaf spring for a suspension system, including a leaf spring body 2. The leaf spring body 2 has elastic properties and can generate an elastic force when compressed. The leaf spring body 2 has a folded structure and is made of composite material.

[0030] Specifically, such as Figure 1 and Figure 2As shown, the leaf spring body 2 includes a first spring segment 201, a second spring segment 202, and a third spring segment 203 arranged sequentially. The first spring segment 201 and the third spring segment 203 are symmetrically arranged. The second spring segment 202 is located between the first spring segment 201 and the third spring segment 203, and its two ends are fixedly connected to the first spring segment 201 and the third spring segment 203, respectively. The thickness of the first spring segment 201 gradually decreases from one end to the other, and the thicker end of the first spring segment 201 is connected to the second spring segment 202. The thickness of the third spring segment 203 gradually decreases from one end to the other, and the thicker end of the third spring segment 203 is connected to the second spring segment 202. The width of the first spring segment 201 gradually decreases from one end to the other, and the wider end of the first spring segment 201 is connected to the second spring segment 202. The width of the third spring segment 203 gradually decreases from one end to the other, and the end of the third spring segment 203 with the larger width is connected to the second spring segment 202.

[0031] like Figure 1 and Figure 2 As shown, the first spring segment 201 is composed of a first reed, which has elastic properties and a certain length, width, and thickness. Figure 4 As shown, dimension a represents the width of the first reed, and dimension b represents the thickness of the first reed. The thickness of the first reed gradually decreases from one end to the other, and the end with the greater thickness is fixedly connected to one end of the second reed segment 202. The width of the first reed gradually decreases from one end along its length to the other, and the end with the greater width of the first reed segment 201 is fixedly connected to one end of the second reed segment 202. The end with the greatest width and the end with the greatest thickness of the first reed are the same end along its length, and only one first reed is provided.

[0032] like Figure 1 and Figure 2 As shown, the third spring segment 203 is composed of a third spring sheet, which has elastic properties and a certain length, width, and thickness. Figure 4 As shown, dimension a represents the width of the third reed, and dimension b represents the thickness of the third reed. The thickness of the third reed gradually decreases from one end to the other, and the end with the greater thickness is fixedly connected to the other end of the second reed segment 202. The width of the third reed gradually decreases from one end along its length to the other, and the end with the greater width of the third reed segment 203 is fixedly connected to the other end of the second reed segment 202. The end with the greatest width and the end with the greatest thickness of the third reed are the same end along its length, and only one third reed is provided. The first and third reeds are arranged symmetrically, therefore the width and thickness at both ends of the first reed are the same as the width and thickness at both ends of the third reed, respectively.

[0033] like Figure 1 and Figure 2 As shown, the second spring segment 202 has a symmetrical structure and is composed of second spring sheets. The second spring sheets possess elastic properties and have specific length, width, and thickness. The width direction of the second spring sheets is parallel to the width directions of the first and third spring sheets. The width and thickness of the second spring sheets remain constant. Multiple second spring sheets are provided and connected sequentially. All second spring sheets have the same width and thickness, and the ends of adjacent second spring sheets are connected by a rounded transition (not a sharp angle). Adjacent second spring sheets are arranged in a V-shape, with an angle less than 180 degrees between their length directions, forming a folded structure for the second spring segment 202. The first and third spring sheets are fixedly connected to one end of each of the two second spring sheets along their length direction, with a rounded transition (not a sharp angle). The ends of these two second spring sheets are the opposite ends of the second spring segment 202 along its length direction. In all the second reeds, for every three consecutive second reeds, the two second reeds at the two ends extend toward the opposite sides of the second reed at the middle position. One end of the first reed along its length is fixedly connected to one end of the second reed along its length, and the angle between their length directions is less than 180 degrees. One end of the third reed along its length is fixedly connected to one end of the second reed along its length, and the angle between their length directions is less than 180 degrees.

[0034] In this embodiment, as Figure 1 and Figure 2 As shown, there are a total of six second reeds.

[0035] like Figures 1 to 3 As shown, the folding angles of the first spring segment 201 and the third spring segment 203 are smaller than the folding angle of the second spring segment 202, and the folding angles of the first spring segment 201 and the third spring segment 203 are the same. The main function of the first spring segment 201 and the third spring segment 203 is to gradually reduce the stiffness of the leaf spring by decreasing the thickness, width and folding angle of the spring.

[0036] The folding angle α1 of the first spring segment 201 refers to the tilt angle of the first spring leaf when the leaf spring is in a vertical state. For example... Figure 3 As shown, when the leaf spring is in a vertical state, the folding angle α1 of the first spring segment 201 is the angle between the line connecting the two opposite ends of the first spring in the length direction and the horizontal plane, and the line connecting the two opposite ends of the first spring in the length direction is perpendicular to the width direction of the first spring.

[0037] The folding angle α2 of the second spring segment 202 refers to the tilt angle of the second spring leaf when the leaf spring is in a vertical state. For example... Figure 3As shown, when the leaf spring is in a vertical state, the folding angle α2 of the second spring segment 202 is the angle between the line connecting the two opposite ends of the second spring in the length direction and the horizontal plane, and the line connecting the two opposite ends of the second spring in the length direction is perpendicular to the width direction of the second spring.

[0038] The folding angle α3 of the third spring segment 203 refers to the tilt angle of the third spring leaf when the leaf spring is in a vertical position. For example... Figure 3 As shown, when the leaf spring is in a vertical state, the folding angle α3 of the third spring segment 203 is the angle between the line connecting the two opposite ends of the third spring in the length direction and the horizontal plane, and the line connecting the two opposite ends of the third spring in the length direction is perpendicular to the width direction of the third spring.

[0039] like Figure 1 and Figure 2 As shown, the leaf spring body 2 also includes a first connecting segment 204 connected to the first spring segment 201 and a second connecting segment 205 connected to the third spring segment 203. The first connecting segment 204 and the second connecting segment 205 are symmetrically arranged, and the length direction of the first connecting segment 204 is parallel to the length direction of the second connecting segment 205. One end of the first connecting segment 204 is fixedly connected to one end of the first spring in the length direction, and the other end of the first spring in the length direction is fixedly connected to one end of the second spring in the length direction. One end of the second connecting segment 205 is fixedly connected to one end of the third spring in the length direction, and the other end of the third spring in the length direction is fixedly connected to one end of the other second spring in the length direction.

[0040] like Figure 1 and Figure 2 As shown, the leaf spring for the suspension system of the present invention also includes two leaf spring mounting bases 1 connected to both ends of the leaf spring body 2. One leaf spring mounting base 1 is connected to the first connecting section 204, and the other leaf spring mounting base 1 is connected to the second connecting section 205. One leaf spring mounting base 1 is fixedly mounted on the vehicle body, and the other leaf spring mounting base 1 is fixedly mounted on the chassis parts of the vehicle. The leaf spring body 2 is located between the two leaf spring mounting bases 1. The leaf spring mounting bases 1 are made of high-strength metal materials such as aluminum alloy and steel.

[0041] As a modified implementation, the first connecting section 204 and the second connecting section 205 can be directly connected to the vehicle body and chassis components. The first connecting section 204 is connected to the vehicle body, and the second connecting section 205 is connected to the vehicle chassis components. The connection method between the first connecting section 204 and the vehicle body can be a plug-in connection or a bolt connection. The connection method between the second connecting section 205 and the chassis components can be a plug-in connection, a bolt connection, or another method.

[0042] Assuming the initial stiffness K of the leaf spring, let the initial stiffnesses of the first spring segment 201, the second spring segment 202, and the third spring segment 203 be K respectively. B K C K D According to the formula for Hooke's spring stiffness, 1 / K = 1 / K B +1 / K C +1 / K D .

[0043] Because the first spring segment 201 and the third spring segment 203 are symmetrical, that is, K B =K D That is, the stiffness formula is: 1 / K = 2 / K B +1 / K C .

[0044] During use, the leaf spring is subjected to loads applied by the vehicle body and chassis components, causing it to compress. In the first stage of elastic deformation, the stiffness of the leaf spring is determined by the formula 1 / K = 2 / K. B +1 / K C Calculate K B and K D The value is greater than zero. Due to the decrease in stiffness of the first spring segment 201 and the third spring segment 203, the deformation of the first spring segment 201 and the third spring segment 203 is relatively large. As the load on the leaf spring gradually increases, the surfaces of the first spring segment 201 and the third spring segment 203 will be in contact with the surface of the leaf spring mounting base 1 (or the surfaces of the first spring segment 201 and the third spring segment 203 will be in contact with the surfaces of the vehicle body and chassis parts, respectively). The first spring leaf is flush with the first connecting segment 204, and the third spring leaf is flush with the second connecting segment 205. As the first spring segment 201 and the third spring segment 203 are completely in contact with the leaf spring mounting base 1, in the second stage of elastic deformation of the leaf spring, the stiffness of the leaf spring is calculated according to the formula of Hooke's spring stiffness. At this time, the stiffness of the leaf spring K = K C K B and K D The stiffness is zero. That is, when the leaf spring is subjected to an external vertical load, the stiffness of the leaf spring gradually increases with the increase of the load. The stiffness reaches its maximum when the first spring segment 201 and the third spring segment 203 are completely in contact with the two leaf spring mounting bases 1 (or when the first spring segment 201 and the third spring segment 203 are respectively in contact with the vehicle body and chassis parts). See the leaf spring stiffness diagram below. Figure 5 .

[0045] Conversely, as the external load on the leaf spring gradually decreases (under the initial load, the first spring segment 201 and the third spring segment 203 are completely in contact with the leaf spring mounting base 1 (or the body and chassis parts), the stiffness of the leaf spring gradually decreases as the surfaces of the first spring segment 201 and the third spring segment 203 gradually separate from the surfaces of the two leaf spring mounting bases 1 (or the first spring segment 201 and the third spring segment 203 are respectively with the surfaces of the body and chassis parts).

[0046] The leaf spring body 2 can be made of continuous fiber reinforced composite materials such as glass fiber, carbon fiber, and basalt fiber. The resin for the composite material can be a thermosetting resin such as polyurethane or epoxy resin, or a thermoplastic resin.

[0047] The spring body is preferably made of thermosetting continuous glass fiber prepreg, but thermoplastic, thermosetting continuous carbon fiber, basalt fiber, and other prepregs can also be used. The spring body is preferably ply-laid in a ±45 degree direction.

[0048] Parameter table of variable stiffness composite folded leaf spring structure

[0049] Number of folds Folding spacing Layer thickness width First connecting section / / 3mm 100mm First reed section 0.5 60 3-4mm 100-150mm Second reed segment 6 75 4mm 150mm Third reed section 0.5 60 3-4mm 100-150mm Second connecting section / / 3mm 150mm

[0050] In this embodiment, as shown in the table above, the thickness of one end of the first spring is 3mm, and the thickness of the other end of the first spring is 4mm, with the thickness gradually decreasing from one end to the other. The thickness of the second spring is 4mm. The thickness of one end of the third spring is 3mm, and the thickness of the other end of the third spring is 4mm, with the thickness gradually decreasing from one end to the other. The width of one end of the first spring is 100mm, and the width of the other end of the first spring is 150mm, with the width gradually decreasing from one end to the other. The width of the second spring is 150mm. The width of one end of the third spring is 100mm, and the width of the other end of the third spring is 150mm, with the width gradually decreasing from one end to the other. The thickness of the first connecting segment 204 is 3mm, and the width of the first connecting segment 204 is 100mm. The thickness of the second connecting segment 205 is 3mm, and the width of the second connecting segment 205 is 150mm. The folding layer spacing of the first spring segment 201 is 60mm, which refers to the vertical distance between the two opposite ends of the first spring sheet along its length. The folding layer spacing of the second spring segment 202 is 75mm, which refers to the vertical distance between the two opposite ends of the second spring sheet along its length. The folding layer spacing of the third spring segment 203 is 60mm, which refers to the vertical distance between the two opposite ends of the third spring sheet along its length.

[0051] The folding leaf spring of this invention has a gradually decreasing stiffness at both ends. Therefore, when subjected to external compressive loads, the deformation at both ends is greater than that in the middle. The two ends first adhere to the vehicle body (or mounting plate), thus increasing the overall stiffness of the spring. Conversely, as the leaf spring returns from a compressed state to its normal state, the overall stiffness gradually decreases. Therefore, throughout its use, the leaf spring achieves a variable stiffness function based on the external load.

[0052] The leaf spring of this invention uses a continuous fiber composite reinforcement material. Continuous fiber reinforced composite materials have extremely high specific strength and specific modulus, and components made from them can achieve a weight reduction of over 30% compared to metal parts. This lightweighting of the leaf spring significantly improves the handling, NVH (noise, vibration, and harshness) performance of the entire vehicle.

[0053] The folding leaf spring of this invention has a simpler structure compared to existing helical springs. During manufacturing, no core mold is required; existing upper and lower molds can be used directly. Therefore, the process cost is low and the process efficiency is high.

[0054] The present invention also provides a vehicle comprising a leaf spring for a suspension system with the above-described structure. The specific structure of this leaf spring for a suspension system can be found in [reference needed]. Figures 1 to 4 Further details will not be elaborated here. Since the vehicle of the present invention includes the leaf springs for the suspension system described in the above embodiments, it possesses all the advantages of the aforementioned leaf springs for suspension systems.

[0055] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A leaf spring for a suspension system, comprising a leaf spring body, characterized in that: The leaf spring body has a folded structure and is made of composite material; The leaf spring body includes a first spring segment, a second spring segment, and a third spring segment arranged in sequence. The first spring segment and the third spring segment are symmetrically arranged. The second spring segment is located between the first spring segment and the third spring segment. The two ends of the second spring segment are fixedly connected to the first spring segment and the third spring segment, respectively. The thickness of the first spring segment gradually decreases from one end to the other, and the end with the greater thickness of the first spring segment connects to the second spring segment; the thickness of the third spring segment gradually decreases from one end to the other, and the end with the greater thickness of the third spring segment connects to the second spring segment; the width of the first spring segment gradually decreases from one end to the other, and the end with the greater width of the first spring segment connects to the second spring segment; the width of the third spring segment gradually decreases from one end to the other, and the end with the greater width of the third spring segment connects to the second spring segment. The first spring segment is composed of a first spring sheet, which has elastic properties. The thickness of the first spring sheet gradually decreases from one end to the other. The end of the first spring sheet with the greater thickness is fixedly connected to one end of the second spring segment. The width of the first spring sheet gradually decreases from one end along its length to the other. The end of the first spring segment with the greater width is fixedly connected to one end of the second spring segment. The end with the greatest width and the end with the greatest thickness of the first spring sheet are the same end along the length of the first spring sheet. Only one first spring sheet is provided. The third spring segment is composed of a third spring sheet, which has elastic properties. The thickness of the third spring sheet gradually decreases from one end to the other, and the end with the greater thickness of the third spring sheet is fixedly connected to the other end of the second spring segment. The width of the third spring sheet gradually decreases from one end along its length to the other end along its length, and the end with the greater width of the third spring segment is fixedly connected to the other end of the second spring segment. The end with the greatest width and the end with the greatest thickness of the third spring sheet are the same end along the length of the third spring sheet, and only one third spring sheet is provided. The first and third reeds are arranged symmetrically, and the width and thickness of the two ends of the first reed are the same as the width and thickness of the two ends of the third reed, respectively. The second spring segment itself has a symmetrical structure. The second spring segment is composed of second spring sheets. The width direction of the second spring sheet is parallel to the width direction of the first spring sheet and the third spring sheet. The width and thickness of the second spring sheet remain unchanged. Multiple second spring sheets are provided and all second spring sheets are connected sequentially. All second spring sheets have the same width and thickness. The ends of two adjacent second spring sheets are connected by a rounded transition. In all the second reeds, two adjacent second reeds are arranged in a V-shape, and the included angle between the length directions of two adjacent second reeds is less than 180 degrees, forming a folded structure for the second spring segment; the first and third reeds are fixedly connected to one end of the length direction of the two second reeds respectively, and the connection is an arc transition, with the ends of the two second reeds being the opposite ends of the length direction of the second spring segment; in all the second reeds, for every three consecutive second reeds, the two second reeds at the two ends extend toward the opposite sides of the second reed at the middle position; one end of the length direction of the first reed is fixedly connected to one end of the length direction of a second reed, and the included angle between their length directions is less than 180 degrees; one end of the length direction of the third reed is fixedly connected to one end of the length direction of a second reed, and the included angle between their length directions is less than 180 degrees. The folding angles of the first and third spring segments are smaller than the folding angle of the second spring segment, and the folding angles of the first and third spring segments are the same. The folding angle of the first spring segment refers to the tilt angle of the first spring leaf when the leaf spring is in a vertical position. The folding angle of the second spring segment refers to the tilt angle of the second spring leaf when the leaf spring is in a vertical position. The folding angle of the third spring segment refers to the tilt angle of the third spring leaf when the leaf spring is in a vertical position.

2. The leaf spring for the suspension system according to claim 1, characterized in that: The leaf spring body also includes a first connecting section connected to the first spring segment and a second connecting section connected to the third spring segment.

3. The leaf spring for the suspension system according to claim 2, characterized in that: The first connecting segment and the second connecting segment are symmetrically arranged, and the length direction of the first connecting segment is parallel to the length direction of the second connecting segment.

4. The leaf spring for the suspension system according to claim 2, characterized in that: It also includes two leaf spring mounting bases connected to both ends of the leaf spring body.

5. The leaf spring for the suspension system according to claim 4, characterized in that: Of the two leaf spring mounting bases, one leaf spring mounting base is connected to the first connecting section, and the other leaf spring mounting base is connected to the second connecting section; one leaf spring mounting base is fixedly installed on the vehicle body, and the other leaf spring mounting base is fixedly installed on the chassis parts of the vehicle, with the leaf spring body located between the two leaf spring mounting bases.

6. The leaf spring for a suspension system according to claim 5, characterized in that: The leaf spring mounting base is made of aluminum alloy or steel.

7. The leaf spring for a suspension system according to any one of claims 1 to 6, characterized in that: The leaf spring body is made of continuous fiber reinforced composite material, and the resin of the composite material is thermosetting resin or thermoplastic resin.

8. The leaf spring for a suspension system according to any one of claims 1 to 6, characterized in that: The leaf spring body is made of glass fiber, carbon fiber or basalt fiber.

9. A vehicle, characterized in that: Includes leaf springs for suspension systems as described in any one of claims 1 to 8.

Images