Riveting structure and method
By using the expansion portion of a tubular fastener in the riveting structure to form a gapless connection with the connected parts, the problems of material damage and stress concentration in the riveting method are solved, the connection efficiency and fatigue performance are improved, the production cost is reduced, and lightweighting is achieved.
Patent Information
- Application Number
- CN202511228797.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-29
- Publication Date
- 2025-11-18
AI Technical Summary
Existing riveting methods suffer from problems such as material damage during hole making, stress concentration, low connection efficiency, and poor structural fatigue performance, resulting in high production costs and hindering lightweighting.
A tubular fastener is inserted into the connected parts through a rivet hole. Multiple expansion parts are formed on the tube wall, including a first expansion part and a second expansion part, which respectively abut against the opposite sides of the connected parts to restrict their displacement. The tubular fastener is expanded and pressed tightly against the hole wall by pressurized liquid to form a gapless connection.
It improves connection efficiency, reduces stress concentration, extends service life, lowers production costs, and helps achieve lightweight connection structures.
Smart Images
Figure CN120969337A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of riveting technology, and specifically to a riveting structure and method. Background Technology
[0002] With the development of the automotive industry, lightweight design and manufacturing has become one of the main directions in automotive design and manufacturing now and in the future. In order to achieve weight reduction in automotive design and manufacturing, in addition to adopting new forming technologies and lightweight materials, lightweight connection structures are also of great significance.
[0003] Assembly and connection are key processes in automobile manufacturing. Common connection methods include adhesive bonding, bolting, welding, self-piercing riveting, and riveting. Existing riveting methods include stamping riveting, rolling riveting, Haclat riveting, zinc alloy rivet rotation, solid rivet self-piercing riveting, and semi-hollow rivet self-piercing riveting, among others.
[0004] However, the relevant riveting methods have at least the following drawbacks: Firstly, damage is easily generated during the hole-making process. During hole processing, the presence of burrs, tear bands, and sharp edges will exacerbate the stress concentration in the hole, leading to a further reduction in its tensile, compressive, or torsional fatigue strength. Therefore, it is necessary to blunt the edges through finishing, shot peening, extrusion, rolling, chamfering, and other processes to reduce stress concentration at the edges.
[0005] However, reducing stress concentration at the edge of the hole requires additional processing costs, especially since the uneven gap between the rivet and the hole of the connected part after extrusion or remelting at the hole end may make it easier for the gap to increase during the service of the riveting, thus deteriorating the performance and life of the riveting structure.
[0006] Secondly, during self-piercing riveting, if the rivet is not held properly or if there is an operational error, the installation process of the rivet will inevitably cause a certain impact on the material surface, and the expansion of the rivet will cause squeezing damage to the material.
[0007] Third, the rivet forming process does not involve uniform expansion as ideally desired, and the upsetting head is prone to misalignment and tilting. Due to inappropriate process parameter selection and / or improper operation, the riveting force is transmitted in a different axis, resulting in an uneven upsetting process. On the misaligned or tilted side, the rivet will cause severe extrusion damage to the material hole wall surface, resulting in interference; while in other areas, there is a rivet hole gap. This interference-gap distribution further exacerbates stress concentration, reduces connection efficiency, and is extremely detrimental to the fatigue performance of the structure. Summary of the Invention
[0008] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a riveting structure and method to solve the technical problems of existing technologies, such as the need for additional hole-making costs, easy material damage from extrusion, significant stress concentration, low connection efficiency, low structural fatigue performance, short service life, and being unfavorable for lightweighting.
[0009] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a riveting structure, comprising: The connected component, wherein a riveting hole is provided through the connected component; and A tubular fastener is inserted through the rivet hole into the connected parts, and its outer wall abuts against and presses against the wall of the rivet hole to connect the connected parts. The tubular fastener has multiple expansion portions on its wall that expand outward under pressure. The multiple expansion portions include at least a first expansion portion and a second expansion portion. The first expansion portion and the second expansion portion are spaced apart along the extension direction of the tubular fastener. The first expansion portion and the second expansion portion abut against the opposite sides of the connected member to limit the displacement of the connected member along the tubular fastener.
[0010] In some embodiments, multiple connected members are provided, and the riveting holes on each connected member are concentrically arranged, and each connected member abuts against the riveting hole in sequence along the extension direction of the riveting hole; the tubular fastener passes through each riveting hole in sequence, and its outer wall abuts against and squeezes the hole wall of each riveting hole respectively, and the first expansion part and the second expansion part abut against the opposite sides of the two connected members that are furthest apart and generate a squeezing effect to limit the displacement of each connected member along the tubular fastener.
[0011] In some embodiments, the plurality of expansion portions further include a plurality of third expansion portions, which are spaced apart along the extension direction of the tubular fastener, and the plurality of third expansion portions respectively fill the gaps on each of the connected members near the wall of the corresponding riveting hole.
[0012] In some embodiments, the riveting hole is a straight through hole, a tapered through hole, or a stepped through hole, and the cross-section of the riveting hole is circular, elliptical, or hexagonal; and the shape of the tubular fastener is adapted to the shape of the riveting hole.
[0013] In some embodiments, the yield strength of the tubular fastener is greater than or equal to 120% of the minimum specified yield strength of the base material of the connected component, and the contact stress between the outer wall of the tubular fastener and the wall of the rivet hole is 110% to 130% of the minimum specified yield strength of the base material of the connected component.
[0014] Secondly, the present invention also provides a riveting method for forming the above-mentioned riveting structure, comprising the following steps: S1. Fix the connected parts; S2. The tubular fastener is inserted into the connected parts through the riveting hole, and a limiting structure is set on the tubular fastener at the position used to form the first expansion part and the second expansion part, respectively. S3. Inject pressurized fluid into the tubular fastener so that the pressurized fluid fills the tubular fastener. S4. Continuously pressurize the fluid and control the tubular fastener to shorten synchronously, so that the tube wall of the tubular fastener expands outward and fits tightly against the wall of the rivet hole until the plurality of expansion parts are formed.
[0015] In some embodiments, in step S1, the connected components are gradually clamped and fixed by a tooling fixture; The tooling fixture is provided with mounting holes for inserting tubular fasteners. During the clamping and fixing of the connected parts, the coaxiality of the mounting hole and the riveting hole is controlled to be greater than or equal to 5% of the product of the diameter of the riveting hole and the elongation of the tubular fastener material; and / or The contact stress at the contact position between the tooling fixture and the connected part is controlled to be greater than or equal to 95% of the minimum specified yield strength of the base material of the connected part.
[0016] In some embodiments, when multiple connected members are provided, when clamping and fixing each connected member, the contact stress of the surfaces of the connected members that abut against each other should be controlled to be greater than or equal to 90% of the minimum specified yield strength of the base material of the connected member.
[0017] In some embodiments, when the tubular fastener passes through the connected component and the tooling fixture, and its tubular wall does not expand, the gap between the outer wall of the tubular fastener and the inner wall of the mounting hole and / or the inner wall of the riveting hole satisfies the following conditions: At any position in the first direction X, the minimum value of the gap is greater than or equal to 0.2 mm, and the ratio of the maximum value of the gap to the distance from the maximum gap point of the tubular fastener at that position to the center of the tubular fastener is less than or equal to 95% of the material elongation of the tubular fastener.
[0018] In some embodiments, in step S4, the continuous pressurization of the pressurized fluid and the synchronous shortening of the tubular fasteners include: The two ends of the tubular fastener are squeezed in a synchronous and centered manner, causing the length of the tubular fastener to shrink and the pressure of the pressurized liquid to continuously increase.
[0019] Compared with the prior art, the riveting structure and method provided by the present invention provides a riveting hole on the connected parts, through which a tubular fastener is inserted into the connected parts. The outer wall of the tubular fastener abuts against the wall of the riveting hole and generates a squeezing effect. The tubular fastener also has a first expansion part and a second expansion part protruding outward on its tubular wall. The first expansion part and the second expansion part can abut against and squeeze the opposite sides of the connected parts respectively, so as to restrict the displacement of the connected parts along the tubular fastener and realize the riveting connection.
[0020] This method ensures gapless riveting between tubular fasteners and connected parts, reduces the processing requirements of riveting holes on connected parts, improves the controllability of riveting operations, avoids interference-gap fit distribution, thereby improving connection efficiency, reducing stress concentration at riveting positions, ensuring the fatigue performance of riveted structures, extending their service life, reducing production costs, and contributing to the lightweighting of connection structures. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the overall structure of the riveting structure in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the overall structure of the riveting structure in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the overall structure of the riveting structure in Embodiment 3 of the present invention; Figure 4 This is a flowchart illustrating the riveting method in Embodiment 4 of the present invention.
[0022] Explanation of reference numerals in the attached drawings: 1. Connected part; 11. Riveting hole; 2. Tubular fastener; 21. First expansion part; 22. Second expansion part; 23. Third expansion part; 3. Tooling fixture; 31. Mounting hole. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0024] To address the aforementioned technical problems, this invention provides a riveting structure and method that can improve connection efficiency, reduce stress concentration at the riveting location, ensure the fatigue performance of the riveting structure, extend its service life, reduce production costs, and contribute to the lightweighting of the connection structure.
[0025] Example 1: Please see Figure 1 , Figure 1This is a schematic diagram of the overall structure of the riveting structure in Embodiment 1 of the present invention. The riveting structure includes multiple connected parts 1 and tubular fasteners 2. Each of the multiple connected parts 1 is provided with a riveting hole 11. The tubular fasteners 2 pass through each of the riveting holes 11 and are simultaneously inserted into each of the connected parts 1, forming a riveting connection with the multiple connected parts 1.
[0026] Specifically, the number of connected parts 1 (i.e., workpieces) can be greater than or equal to 3; for example, connected parts 1 can be set to 5. The specific structure of connected parts 1 is not limited; for example, connected parts 1 can be set as follows: Figure 1 The plates shown can be made of different materials and have different dimensions, depending on the actual needs of production. They can be the same or different, and no specific restrictions are required.
[0027] In practical applications, when all five connected parts 1 are plates, they can be placed side by side and fitted together sequentially. In this case, the rivet holes 11 on the five connected parts 1 can be aligned with each other, forming a coaxial structure.
[0028] It should be noted that, taking any of the connected parts 1 as an example, the corresponding riveting hole 11 can be processed according to the load-bearing conditions of the connected part 1 (such as size, direction and whether it is under dynamic load), the usage environment and the requirements of the riveting action environment, so as to determine the position, shape and size parameters of the corresponding riveting hole 11.
[0029] For example, the rivet hole 11 can be a straight through hole, a tapered through hole, a stepped through hole, or a hole of other structures, and the cross-section of the rivet hole 11 (i.e. the cross-section perpendicular to its extension direction) can be circular, elliptical, hexagonal, or other shapes, without specific limitations.
[0030] Based on this, the edges of the riveting hole 11 can also be chamfered, rounded, or otherwise processed, and the processing accuracy of the riveting hole 11 does not need to be specifically required. For example, in one case, the connected parts 1 can be directly riveted after being squeezed at the hole end or remelted at the hole wall.
[0031] The aforementioned tubular fastener 2 can be a pipe fitting, which is matched with the aforementioned connected part 1. The so-called matching means that the material, shape, size and quantity of the pipe fitting need to meet the requirements of the connected part 1 for load-bearing capacity (size, direction and whether it is dynamic load, etc.), usage environment and riveting operation environment.
[0032] Based on this, the cross-sectional shape of the pipe fitting can be circular, elliptical, hexagonal, or other shapes, and its shape is preferably adapted to the shape of the rivet holes. The dimensions of the pipe fitting should ensure that it can pass through all the rivet holes 11 simultaneously. For example, when the cross-sections of both the pipe fitting and the rivet holes 11 are circular, and all the rivet holes 11 are through holes, the outer diameter of the pipe fitting should be less than or equal to the diameter of the smallest rivet hole 11 among all the rivet holes 11.
[0033] Meanwhile, the yield strength of the pipe fitting material is preferably greater than or equal to 120% of the minimum specified yield strength of the base material of the connected part 1, and the pipe fitting material (including surface treatment material and process) and the material of the connected part 1 (including surface treatment material and process) are preferably not subject to electrochemical corrosion.
[0034] In this embodiment, the five connected parts 1 are all plates, and the riveting holes 11 on the five plates can all be set as through holes, and each through hole has the same diameter and a circular cross-section.
[0035] Based on this, the aforementioned tubular fastener 2 can be a circular straight tube. When the various plates are placed side by side and fixed by the tooling fixture 3, the rivet holes 11 on each plate are aligned with each other, forming a coaxial structure. The tubular fastener 2 can pass through each rivet hole 11 in sequence, so that the tubular fastener 2 can be simultaneously inserted into each connected component 1.
[0036] At this time, the tooling fixture 3 can clamp each of the connected parts 1 and eliminate the gaps between the plates of each connected part 1. The tubular fastener 2 passes through each riveting hole 11 and the through hole on the tooling fixture 3, thereby entering the riveting state with each of the connected parts 1.
[0037] like Figure 1 As shown, pressurized liquid can be injected into the tubular fastener 2. By continuously increasing the pressure of the pressurized liquid and controlling the length of the tubular fastener 2 to shorten synchronously, the tube wall of the tubular fastener 2 will expand outward under the pressure, thereby forming multiple expansion parts. The tubular fastener 2 can form a reliable connection with each connected part 1 through multiple expansion parts, that is, the tubular fastener 2 can be used to rivet multiple connected parts 1 (i.e., workpieces).
[0038] In this embodiment, the above-mentioned multiple expansion portions may include a first expansion portion 21 and a second expansion portion 22. The first expansion portion 21 and the second expansion portion 22 are arranged at intervals along the extension direction of the tubular fastener 2, and the first expansion portion 21 and the second expansion portion 22 may be located on opposite sides of the integral structure formed by each connected member 1.
[0039] The first expansion part 21 can abut against and squeeze the outermost connected member 1 inward, while the second expansion part 22 can abut against and squeeze the outermost connected member 1 inward. That is, the first expansion part 21 and the second expansion part 22 can abut against the opposite sides of the two connected members 1 that are furthest apart, and generate a mutual squeezing effect.
[0040] Thus, the inward squeezing action of the first expansion part 21 and the second expansion part 22 on each connected member 1 can limit the displacement of each connected member 1 along the extension direction of the tubular fastener 2, so as to achieve a reliable connection of each connected member 1.
[0041] Based on this, when the riveting holes 11 of each connected part 1 are provided with chamfers, fillets or other diameter reduction process structures, any two adjacent connected parts 1 will form an inverted triangle or other recessed structure at the splicing of their riveting holes 11.
[0042] At this time, the tubular fastener 2 is subjected to the combined action of the compression at both ends and the internal liquid pressure. The aforementioned multiple expansion parts may also include multiple third expansion parts 23, and the multiple third expansion parts 23 are arranged in a one-to-one correspondence with the recessed structure formed at the splice of each connected part 1.
[0043] like Figure 1 As shown, when the rivet holes 11 of the above 5 connected parts 1 are all chamfered, an inverted triangular recessed structure is formed at the splicing point of the rivet holes 11 of any two adjacent connected parts 1, that is, there are 4 inverted triangular recessed structures.
[0044] At this time, four third expansion portions 23 are also provided. The four third expansion portions 23 are respectively embedded in the four inverted triangular recessed structures and fully fill the gaps formed by the corresponding recessed structures.
[0045] Thus, the tubular fastener 2 can be formed into a bamboo-joint rivet fastener, with multiple bamboo-joint-like protrusions formed on its outer wall.
[0046] It should be noted that the formation of the first expansion portion 21 is due to the combined effect of liquid pressure and extrusion at both ends on the tubular fastener 2. When the pressure exceeds the yield strength of the tubular fastener 2, the tubular fastener 2 undergoes plastic deformation, thereby expanding and deforming outwards from the tube wall. On the other hand, the size of its expansion area (which can be understood as the length of the expansion area along the tubular fastener 2) is determined by the limiting of the connected part 1 and the tooling fixture 3.
[0047] For example, the side of the first expansion part 21 close to the connected part 1 expands and deforms in contact with the end face of the adjacent connected part 1, while the side of the first expansion part 21 away from the connected part 1 expands and deforms under the limitation of the tooling fixture 3.
[0048] Similarly, the formation of the second expansion portion 22 and each of the third expansion portions 23 can be achieved by finding corresponding limiting structures to ensure that they form the corresponding expansion structures.
[0049] With this in mind, in practical applications, the specific parameters (such as the size of the expansion area, the expansion height, etc.) of the first expansion part 21 and the second expansion part 22 can be changed by altering the limiting structure of the contact area between the tooling fixture 3 and the tubular fastener 2. The specific settings can be flexibly configured as needed, and will not be elaborated further here.
[0050] Of course, the specific structure of each third expansion part 23 can also be flexibly adjusted by changing the recessed structure at the splicing of each rivet hole 11, which will not be elaborated further.
[0051] Finally, when each expansion part is fully formed, even if the outer diameter of the tubular fastener 2 is slightly smaller than the diameter of the rivet hole 11 initially, the outer wall of the tubular fastener 2 can abut against and fit the hole wall of each rivet hole 11; the first expansion part 21 and the second expansion part 22 abut against the mutually opposite surfaces of the two connected parts 1 that are furthest apart, while each third expansion part 23 fills the recessed structure formed at the splice of each rivet hole 11.
[0052] At this time, the contact stress between the outer wall of the tubular fastener 2 and the hole wall of any rivet hole 11 is preferably 110% to 130% of the minimum specified yield strength of the base material of the connected part 1.
[0053] However, it should be noted that in this embodiment, the connected parts 1 are all plates, and each riveting hole 11 is a straight through hole with a circular cross-section, and the diameter of each straight through hole is the same, so the tubular fastener 2 can be a straight round tube.
[0054] However, in other implementation scenarios, when the connected part 1 is not a plate, or when each rivet hole 11 is not a through hole, or when the cross-section of each rivet hole 11 is not a circle, or when the diameter of each through hole is not exactly the same, the shape and size of the tubular fastener 2 can be adaptively adjusted according to the shape and size of each rivet hole 11, so as to ensure that the tubular fastener 2 can be inserted into each connected part 1 at the same time, and that the tubular fastener 2 forms a reliable connection with all connected parts 1 after expansion.
[0055] For example, when each connected part 1 is a plate and each rivet hole 11 is a through hole, but the cross-section of each through hole is elliptical, the cross-section of the tubular fastener 2 can be set to be elliptical accordingly.
[0056] Furthermore, when each connected component 1 is a plate and each riveting hole 11 is a tapered through hole, the tubular fastener 2 can be a straight round tube. It is only necessary to ensure that the first expansion portion 21 and the second expansion portion 22 can be formed on the tubular fastener 2, and that each third expansion portion 23 can fully fill the corresponding recessed structure. Similarly, this can be deduced, and will not be elaborated further here.
[0057] Furthermore, it should be noted that this embodiment describes the scenario where a single tubular fastener 2 is provided on multiple connected parts 1. However, in other implementations, depending on the load-bearing requirements of the connected parts 1, multiple tubular fasteners 2 can be provided on multiple connected parts 1 simultaneously. The connection structure and principle between each tubular fastener 2 and the connected part 1 remain unchanged, thereby forming multiple riveting structures on the connected parts 1. The actual number of tubular fasteners 2 can be flexibly determined according to needs, and will not be elaborated further here.
[0058] Example 2: Please see Figure 2 The specific structural form of this embodiment is basically the same as that of embodiment 1. The difference lies in the number of connected parts 1 and the specific distribution of multiple expansion parts on the tubular fastener 2.
[0059] In this embodiment, there are two connected parts 1. Both connected parts 1 can be set as plates, and both plates are provided with rivet holes 11.
[0060] Based on this, the tubular fastener 2 is inserted into the two connected parts 1 through two riveting holes 11. The outer wall of the tubular fastener 2 expands under pressure to form multiple expansion parts, including a first expansion part 21, a second expansion part 22 and a third expansion part 23. The first expansion part 21 and the second expansion part 22 respectively abut against the mutually opposite surfaces of the two connected parts 1, while the third expansion part 23 fills the recessed structure at the joint of the two riveting holes 11.
[0061] It is understandable that when there are two connected parts 1 (i.e. workpieces), the two connected parts 1 can be reliably riveted together with the matching tubular fasteners 2. The specific riveting principle can be found in the relevant description in Example 1, and will not be repeated here.
[0062] Of course, the tubular fastener 2 can also be adapted to different structural forms of the connected part 1 and its riveting hole 11. For specific changes, please refer to the relevant description in Embodiment 1, which will not be repeated here.
[0063] Example 3: Please see Figure 3This embodiment is basically the same as the specific structural form of embodiment 1 or embodiment 2, the difference being the number of connected parts 1 and the purpose of riveting.
[0064] In Embodiment 1 or Embodiment 2, the tubular fastener 2 is used to connect each of the connected parts 1. However, in this embodiment, the tubular fastener 2 itself constitutes one of the connecting parts (i.e., the tubular part). Thus, this embodiment actually provides a structural form for tube-plate riveting connection.
[0065] Specifically, the riveting structure includes a connected component 1, which can be a plate. A riveting hole 11 is formed through the plate, and the cross-section of the riveting hole 11 can be elliptical. Correspondingly, a pipe is inserted through the riveting hole 11, and the outer wall of the pipe abuts against the wall of the riveting hole 11. That is, the cross-section of the pipe is also elliptical, and the outer wall of the pipe is expanded to form a first expansion portion 21 and a second expansion portion 22. The first expansion portion 21 and the second expansion portion 22 abut against the opposite sides of the plate to form a reliable connection with the plate.
[0066] It should be noted that although the pipe itself constitutes one of the connecting parts in this embodiment, the connection principle between the pipe and the plate is still based on the riveting achieved by the expansion and deformation of the pipe, which is the same as the formation principle of the riveting structure in Embodiment 1 or Embodiment 2.
[0067] Based on this, the pipe fitting can also be adapted to different structural forms of the connected part 1 and its riveting hole 11. The specific changes can also be described in the relevant description in Example 1, and will not be repeated here.
[0068] Example 4: Please see Figure 4 The present invention also provides a riveting method, which can be used to form the riveting structure in Embodiment 1, Embodiment 2 or Embodiment 3 to achieve a reliable connection of multiple connected parts 1, or to achieve a reliable connection between pipe and plate.
[0069] Combined with appendix Figure 1 Taking the riveting structure in Example 1 as an example, the riveting method includes the following steps: S1, Fix the connected part 1; S2. The tubular fastener 2 is inserted into the connected part 1 through the riveting hole 11, and a limiting structure is set on the tubular fastener 2 at the positions used to form the first expansion part 21 and the second expansion part 22, respectively. S3. Inject pressurized liquid into the tubular fastener 2 so that the pressurized liquid fills the tubular fastener 2. S4. Continuously pressurize the pressure liquid and control the tubular fastener to shorten synchronously, so that the tube wall of the tubular fastener 2 expands outward and fits tightly against the wall of the rivet hole 11 until the above-mentioned multiple expansion parts are formed.
[0070] In practical applications, tubular fasteners 2 and tooling fixtures 3 can be matched according to the material, thickness, load-bearing conditions (such as length, size, direction and whether dynamic load is applied), usage environment and riveting operation environment of the connected parts 1, and the riveting holes 11 on each connected part 1 can be processed accordingly.
[0071] Among the factors that can be considered are at least: the yield strength of the tubular fastener 2 material is preferably greater than or equal to 120% of the minimum specified yield strength of the base material of the connected part 1, and the material of the tubular fastener 2 (including surface treatment material and process) and the material of the connected part 1 (including surface treatment material and process) are preferably not subject to electrochemical corrosion.
[0072] In step S1, the rivet hole 11 of one of the outermost connected parts 1 can be used as the positioning reference for the tooling fixture 3 used in the riveting process. The tooling fixture 3 with a bell-shaped inner cavity can be used to gradually press each connected part 1, so that the mounting hole 31 on the tooling fixture 3 is aligned with each rivet hole 11, and the gap between each connected part 1 is eliminated.
[0073] In the actual compaction process, at least the following conditions should be preferably met: First, the coaxiality of the mounting hole 31 and the riveting hole 11 on the tooling fixture 3 is greater than or equal to 5% of the product of the diameter of the riveting hole 11 and the elongation of the tubular fastener 2 material.
[0074] Secondly, on the premise of ensuring that each contact surface of each connected part 1 is not crushed, the contact stress at the contact position between the tooling fixture 3 and the connected part 1 is greater than or equal to 95% of the minimum specified yield strength of the base material of the connected part 1.
[0075] Third, the contact stress of the surfaces of each connected component 1 that come into contact with each other is greater than or equal to 90% of the minimum specified yield strength of the base material of the connected component 1.
[0076] Based on this, the tooling fixture 3 can be used to press and fix each connected part 1, which facilitates the subsequent riveting steps.
[0077] In step S2, when each connected component 1 is initially fixed by the tooling fixture 3, the tubular fastener 2 can be inserted into each connected component 1 through each riveting hole 11; at this time, the tubular fastener 2 also actually passes through the mounting hole 31 on the tooling fixture 3.
[0078] Based on this, the part of the tooling fixture 3 used to clamp each connected component 1 can simultaneously form a limiting structure for the tubular fastener 2. Taking the limiting structure on one side as an example, this limiting structure abuts against the adjacent connected component 1 on one hand, and can also abut against the tubular fastener 2 on the other hand, so that when the tubular fastener 2 expands subsequently, it can form the aforementioned first expansion part 21 or second expansion part 22 at the limiting point.
[0079] At this time, when the tubular fastener 2 is inserted into the connected part 1 and the tooling fixture 3, and its tube wall does not expand, the gap between the outer wall of the tubular fastener 2 and the inner wall of the mounting hole 31 and / or the inner wall of the riveting hole 11 preferably satisfies the following conditions: At any position in the first direction X, the minimum value of the aforementioned gap is greater than or equal to 0.2 mm, and the ratio of the maximum value of the aforementioned gap to the distance from the maximum gap point of the tubular fastener 2 at that position to the center of the tubular fastener 2 is less than or equal to 95% of the material elongation of the tubular fastener 2.
[0080] Specifically, in this embodiment, the tubular fastener 2 can be a straight round tube, and each riveting hole 11 and the mounting hole 31 on the tooling fixture 3 can be a circular through hole. Therefore, the above conditions are actually equivalent to: at any position in the axial direction of the tubular fastener 2, the gap between the outer wall of the tubular fastener 2 and the inner wall of the mounting hole 31 and / or the riveting hole 11 should be greater than or equal to 0.2 mm, and the ratio of the maximum value of the gap at this position to the radius of the outer circumference of the tubular fastener 2 is less than or equal to 95% of the material elongation of the tubular fastener 2.
[0081] In other embodiments, when the shapes of the mounting hole 31, the riveting hole 11, and the tubular fastener 2 change (for example, when the cross-sections of all three are elliptical), the aforementioned gap may not be a fixed value, but it will have at least one minimum value and one maximum value at the same time; wherein, the minimum value should be greater than or equal to 0.2 mm, and the ratio of the maximum value to the distance from the maximum gap point of the tubular fastener 2 at the corresponding position to the center of the tubular fastener 2 is less than or equal to 95% of the material elongation of the tubular fastener 2.
[0082] It should be noted that the maximum gap point mentioned above refers to: along the first direction X (i.e. the extension direction of the tubular fastener 2), at any selected position on the tubular fastener 2, even if the tubular fastener 2 is not a straight round tube, there is at least one point on the outer wall of the tubular fastener 2 at this point, and the distance from this point to the inner wall of the rivet hole 11 is the greatest in the direction of the line connecting this point and the center of the tubular fastener 2.
[0083] At this point, the point is the "maximum gap point" mentioned above, and the distance from this point to the inner wall of the rivet hole 11 is the "maximum gap value" mentioned above. The "ratio of the maximum gap value to the distance from the maximum gap point of the tubular fastener 2 at this position to the center of the tubular fastener 2" is the ratio of the distance from the actual maximum gap point to the inner wall of the rivet hole 11 (in the direction of the line connecting this point and the center of the tubular fastener 2) to the distance from this point to the center of the tubular fastener 2.
[0084] After completing the above preparations, step S3 can be started. In step S3, pressurized fluid can be injected into the tubular fastener 2, filling it completely. The specific type of pressurized fluid can be flexibly selected as needed; for example, it can be hydraulic oil commonly used in hydraulic systems, or other pressurized fluids. After the pressurized fluid is injected into the tubular fastener 2, the openings at both ends of the fastener 2 can be sealed to prevent the pressurized fluid from leaking out.
[0085] In step S4, after the pressurized fluid fills the tubular fastener 2 and the seal is completed, the two ends of the tubular fastener 2 can be squeezed by a hydraulic device, causing the tubular fastener 2 to shorten and the pressure of the pressurized fluid to increase simultaneously. When the pressure exerted on the tubular fastener 2 exceeds the yield limit of the tubular fastener 2, the tube wall of the tubular fastener 2 will undergo plastic deformation, causing its tube wall to expand outward and adhere to the wall of the riveting hole 11 on each connected component 1, until multiple expansion parts are formed as in Embodiment 1.
[0086] During this process, the tubular fastener 2 can flow along the inner cavity of the mounting hole 31 and expand outward with the help of the inner cavity of the mounting hole 31 and the adjacent riveting hole 11 to form an enlarged rivet head. There are two enlarged rivet heads on the tubular fastener 2, and the two enlarged rivet heads respectively constitute the first expansion part 21 and the second expansion part 22 mentioned above.
[0087] Ultimately, the outer wall of the tubular fastener 2 abuts against and presses against the inner walls of each rivet hole 11. The first expansion portion 21 and the second expansion portion 22 abut against the two farthest surfaces of the connected parts 1, exerting a pressing effect on them. Meanwhile, each third expansion portion 23 fills the recessed structure formed at the joint of each rivet hole 11, thereby completely eliminating the gap between the tubular fastener 2 and the connected parts 1, achieving uniform load-bearing of the tubular fastener 2.
[0088] At this time, with the help of the first expansion part 21, the second expansion part 22 and the multiple third expansion parts 23, the tubular fastener 2 will form a bamboo-joint rivet fastener.
[0089] It should be noted that during the riveting process between the tubular fastener 2 and the connected part 1, it is also preferred to ensure that the contact stress between the outer wall of the tubular fastener 2 and the surface of the connected part 1 is 110% to 130% of the minimum specified yield strength of the base material of the connected part 1.
[0090] Meanwhile, the aforementioned "continuous pressurization of the fluid and control of synchronous shortening of the tubular fastener" can actually be implemented using different pressurization methods as needed. For example, in one implementation, two horizontal or vertical side cylinders of a hydraulic press can move synchronously and centeredly, respectively squeezing both ends of the tubular fastener 2, causing the tubular fastener 2 to shorten under pressure, thereby causing the fluid pressure inside the tubular fastener 2 to increase synchronously.
[0091] At this point, when the pressure required for expansion is reached, the tubular fastener 2 will undergo plastic deformation under the combined action of the hydraulic press and the liquid pressure, eventually expanding and forming the aforementioned multiple expansion parts.
[0092] In other implementation scenarios, the aforementioned pressurization method can also be O-ring method or liquid bag expansion, etc., and there is no specific limitation on this.
[0093] After completing the above steps, when more riveting positions need to be set on each connected part 1, the tooling fixture 3 can be loosened and the above steps S1-S4 can be repeated until all the required riveting connections are completed on each connected part 1.
[0094] Based on this, it should be noted that although the riveting method provided in this embodiment is described in relation to Embodiment 1 above, it can also be used to realize other forms of riveting connection structures in other implementation scenarios when the riveting principle remains unchanged. For example, it can also be used to realize riveting connection structures modified based on Embodiments 2 or 3, or other embodiments 1-3. The specific details will not be elaborated further.
[0095] As explained above, in all riveting connections formed using this method, each rivet (i.e., the tubular fastener 2) ensures that its outer wall is tightly fitted against the hole wall of the connected component 1, avoiding gaps. Therefore, under load, all rivets (i.e., the tubular fasteners 2) can bear the load simultaneously, avoiding the uneven load-bearing capacity of rivets due to gaps in traditional solid rivet connections, or the increase in structural weight caused by the actual rivet diameter being larger than the required rivet size.
[0096] Meanwhile, the riveting hole 11 on the connected part 1 can be a through hole, a countersunk hole or other hole type, and its cross-sectional shape can be circular, elliptical, hexagonal or other shapes; the edge of the riveting hole 11 can be chamfered, and the machining accuracy of the riveting hole 11 does not need to be specially required. For example, the connected part 1 after the hole end is extruded or the hole wall is remelted can also be riveted directly.
[0097] Furthermore, this riveting method can achieve lightweight and reliable connections for tube-plate joints or structures with poor weldability that cannot be accomplished by traditional welding processes. For example, when the connected part 1 is a cold-work hardened or cold-formed strengthened material, such as cold-drawn steel, H-temper 5-series aluminum alloys, and cold-bent deformation parts of cold-formed profiles; or when the connected part 1 is a heat-treated strengthened material, such as medium-carbon quenched and tempered steel, hot-formed steel, low-alloy high-strength steel with a strength exceeding 700 MPa, and T6-temper 2-series, 6-series, and 7-series aluminum alloys; or when the connected part 1 is a material or composite material with a surface coating, such as workpieces with shop primer, aluminized steel plates, and copper-steel clad steel plates; or when the connected part 1 is a dissimilar material connection structure, such as a connection structure between ferritic steel and austenitic steel, steel and non-ferrous metals and alloys, or steel and cast iron, lightweight and reliable connections can all be achieved through the above riveting method.
[0098] In the description of this application, it should be noted that the terms "upper" and "lower," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0099] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0100] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A riveting structure, characterized in that, include: The connected component has a through-hole for riveting; as well as A tubular fastener is inserted through the rivet hole into the connected parts, and its outer wall abuts against and presses against the wall of the rivet hole to connect the connected parts. The tubular fastener has multiple expansion portions on its wall that expand outward under pressure. The multiple expansion portions include at least a first expansion portion and a second expansion portion. The first expansion portion and the second expansion portion are spaced apart along the extension direction of the tubular fastener. The first expansion portion and the second expansion portion abut against the opposite sides of the connected member to limit the displacement of the connected member along the tubular fastener.
2. The riveting structure according to claim 1, characterized in that, The connected components are provided in multiple ways, and the riveting holes on each of the connected components are arranged concentrically. Each of the connected components abuts against the riveting holes in sequence along the extension direction of the riveting holes. The tubular fastener passes through each of the riveting holes in sequence, and its outer wall abuts against and squeezes the hole wall of each of the riveting holes. The first expansion part and the second expansion part abut against the opposite sides of the two connected components that are furthest apart and generate a squeezing effect to limit the displacement of each of the connected components along the tubular fastener.
3. The riveting structure according to claim 2, characterized in that, The plurality of expansion portions further include a plurality of third expansion portions, which are spaced apart along the extension direction of the tubular fastener, and each of the plurality of third expansion portions fills the gap on each of the connected parts near the wall of the corresponding riveting hole.
4. The riveting structure according to claim 1, characterized in that, The rivet hole is a straight through hole, a tapered through hole, or a stepped through hole, and the cross-section of the rivet hole is circular, elliptical, or hexagonal; and the shape of the tubular fastener is adapted to the shape of the rivet hole.
5. The riveting structure according to claim 1, characterized in that, The yield strength of the tubular fastener is greater than or equal to 120% of the minimum specified yield strength of the base material of the connected parts, and the contact stress between the outer wall of the tubular fastener and the wall of the rivet hole is 110% to 130% of the minimum specified yield strength of the base material of the connected parts.
6. A riveting method for forming a riveting structure as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Fix the connected parts; S2. The tubular fastener is inserted into the connected parts through the riveting hole, and a limiting structure is set on the tubular fastener at the position used to form the first expansion part and the second expansion part, respectively. S3. Inject pressurized fluid into the tubular fastener so that the pressurized fluid fills the tubular fastener. S4. Continuously pressurize the fluid and control the tubular fastener to shorten synchronously, so that the tube wall of the tubular fastener expands outward and fits tightly against the wall of the rivet hole until the plurality of expansion parts are formed.
7. The riveting method according to claim 6, characterized in that, In step S1, the connected parts are gradually clamped and fixed by tooling fixtures; The tooling fixture is provided with mounting holes for inserting tubular fasteners. During the clamping and fixing of the connected parts, the coaxiality of the mounting hole and the riveting hole is controlled to be greater than or equal to 5% of the product of the diameter of the riveting hole and the elongation of the tubular fastener material; and / or The contact stress at the contact position between the tooling fixture and the connected part is controlled to be greater than or equal to 95% of the minimum specified yield strength of the base material of the connected part.
8. The riveting method according to claim 7, characterized in that, When multiple connected components are configured, when clamping and fixing each connected component, the contact stress of the surfaces of the connected components that abut against each other should be controlled to be greater than or equal to 90% of the minimum specified yield strength of the base material of the connected component.
9. The riveting method according to claim 7, characterized in that, When the tubular fastener is inserted into the connected component and the tooling fixture, and its tubular wall does not expand, the gap between the outer wall of the tubular fastener and the inner wall of the mounting hole and / or the inner wall of the riveting hole satisfies the following conditions: At any position in the first direction X, the minimum value of the gap is greater than or equal to 0.2 mm, and the ratio of the maximum value of the gap to the distance from the maximum gap point of the tubular fastener at that position to the center of the tubular fastener is less than or equal to 95% of the material elongation of the tubular fastener.
10. The riveting method according to any one of claims 6-9, characterized in that, In step S4, the continuous pressurization of the pressurized liquid and the synchronous shortening of the tubular fasteners include: The two ends of the tubular fastener are squeezed in a synchronous and centered manner, causing the length of the tubular fastener to shrink and the pressure of the pressurized liquid to continuously increase.