Metal plate bonding method

Abstract

This invention provides a method for joining metal plates that enables high-strength and high-precision bonding even between dissimilar materials. [Solution] Through holes of substantially the same diameter are provided in both the first metal plate and the second metal plate, the first metal plate is laminated on the second metal plate so that the through holes overlap, a plug 1 having a main body portion with a diameter substantially equal to the diameter of the through hole and a flange portion 12 larger than the diameter on one side is inserted into the through hole, and pressure is applied to the upper surface of the first metal plate including the plug and the lower surface of the second metal plate around the bottom surface of the plug, thereby causing the flange portion to enter the first metal plate and the end of the plug facing the flange portion to penetrate the second metal plate around the plug, thereby causing the respective metal plate materials to plastically flow toward the main body surface of the plug and applying tightening stress to the plug, thereby joining the first and second metal plates through the plug.

Description

【Technical Field】 【0001】 The present invention relates to a method for bonding metal plates that can firmly bond even异种materials. 【Background Art】 【0002】 Metal plates are used in many fields, and many types of bonding methods are known. Typical bonding methods include bolts and nuts, mechanical clinching, rivets, etc. For example, it is disclosed in Patent Document 1. In the case of bolts and nuts, there is a problem that two types of bonding members are required and it takes time for bonding. On the other hand, in the case of mechanical clinching or rivets, it is a method of forming an anchor by pushing a hard punch or rivet into a soft material and deforming the soft material itself or the rivet. However, since the rivet is a hard material, a large amount of anchor cannot be obtained. In addition, a gap occurs between the soft material and the rivet, or the clamping force between the soft material and the rivet is weak, resulting in low strength. 【0003】 Patent Document 2 discloses a bonding structure and a bonding device for metal members using plastic flow bonding. This technology describes a method and device for bonding a first metal member having an annular portion using a restraint ring to a second metal member having an axial portion. By using plastic flow bonding, high-strength and high-precision metal bonding can be performed, but this technology cannot be directly applied to the bonding of metal plate members. 【0004】 It should be noted that the term "异种materials" in the original text is not a standard or common expression. It might be a misspelling or an unclear term. If it has a specific meaning in the relevant context, it should be accurately translated according to that meaning. Here, it is tentatively left as "异种materials" for the purpose of following the translation rules strictly.Patent Document 3 discloses a technique for joining metal plates using rivets having a frustum-shaped head and shank. In this technique, a hole is formed through two metal plates by directly driving in the rivet without forming a through hole in the members to be joined beforehand, and then a groove is formed by coining the structural member around the end of the rivet shaft. Multiple shank grooves are formed on the rivet shaft, and it is described that the structural member enters these shank grooves due to plastic deformation during the coining of the structural member. In this technique, the head of the rivet enters the structural member after joining, but because the lower side of the head is frustum-shaped, the stress acts in a direction that expands the structural member and is not sufficiently transmitted to the structural member, so it is impossible for the structural member to tighten the rivet shaft with strong force or to undergo plastic flow. Plastic flow occurs in the lower structural member due to the coining and it joins with the rivet shaft. Therefore, the upper structural member is connected to the lower structural member, which is joined by rivets, only by compressive stress from the rivet tips, resulting in a weak connection. 【0005】 Patent Document 4 discloses a punch rivet consisting of a head portion and a shaft portion connected longitudinally to the head portion. The shaft portion has a punching edge at the end away from the head portion, and the head portion, which is the end away from the shaft portion, has a larger diameter than the shaft portion. In this rivet, the head portion is divided into multiple sub-portions separated longitudinally. In this technology as well, two metal plates are joined by directly driving the rivet into the members to be joined without forming through holes in the members beforehand. Figure 1 of this publication shows that the material of the lower (die side) component flows into an annular recess during the riveting process, which is considered to be plastic flow. However, even in this technology, because the lower part of the head portion is divided into multiple sub-portions separated longitudinally, the stress of the head portion is not sufficiently transmitted to the structural member, making it impossible to induce plastic flow. Therefore, similar to Patent Document 3, the upper structural member is connected to the lower structural member, which is connected by rivets, only by compressive stress from the rivet tips, resulting in a weak bonding force. [Prior art documents] [Patent Documents] 【0006】 [Patent Document 1] Japanese Patent Publication No. 2013-130238 [Patent Document 2] Republished Patent Publication No. 2011 / 118219 [Patent Document 3] U.S. Patent Publication No. 6527490 [Patent Document 4] European Patent Publication EP2671654A2 [Overview of the Initiative] [Problems that the invention aims to solve] 【0007】 In view of the above-mentioned problems, the present invention aims to provide a method for joining metal plates that can bond dissimilar materials with high strength and precision. [Means for solving the problem] 【0008】 To solve the above-mentioned problems, the metal plate joining method according to the present invention provides through holes of substantially the same diameter in both the first metal plate and the second metal plate, and laminates the first metal plate on the second metal plate so that the through holes overlap. A plug having a main body with a diameter approximately equal to the diameter of the through hole and a flange on one side that is larger than the diameter of the through hole is inserted into the through hole. The upper surface of the first metal plate, including the plug, is pressurized by a pressure plate or the like to cause the flange portion to penetrate into the first metal plate. Furthermore, at the end of the plug facing the flange, the punch tip is inserted into the second metal plate surrounding the plug, The first and second metal plates are joined together through the plug by causing each metal plate material to undergo plastic flow toward the surface of the plug body, thereby applying a tightening stress to the plug. 【0009】 It is preferable to provide a plurality of circumferential grooves on the main body surface of the plug, near the flange, and near the plug end facing the flange. 【0010】 Another feature of the metal plate joining method according to the present invention is that through holes are provided in both the first metal plate and the second metal plate such that the diameter of the through hole in the first metal plate > the diameter of the through hole in the second metal plate, and the first metal plate is laminated on the second metal plate so that the through holes overlap. A plug is inserted into the through hole, having a main body portion with a stepped portion formed such that the upper part is approximately equal in diameter to the through hole of the first metal plate and the lower part is approximately equal in diameter to the through hole of the second metal plate, and a flange portion at the upper end that is larger than the diameter of the upper part of the main body. By applying pressure to the upper surface of the first metal plate, including the plug, and the lower surface of the second metal plate using a pressure plate or the like, the flange portion is forced into the first metal plate and the stepped portion of the plug is forced into the second metal plate, thereby causing the metal plate material around the flange portion and the stepped portion to plastically flow toward the main surface of the plug, thereby applying tightening stress to the plug. The result is to join the first and second metal plates together. 【0011】 It is preferable to provide a plurality of circumferential grooves on the main body surface of the plug, near the flange, and near the stepped portion. 【0012】 The plug used in the metal plate bonding method according to the present invention is preferably harder than either of the first or second metal plates. [Effects of the Invention] 【0013】 The metal plate joining method according to the present invention requires less stress for joining compared to the conventional method of directly driving rivets into the metal plates to be joined without pre-drilling holes in them. Furthermore, by using a pressure plate to insert the flange portion of the plug into the upper metal plate, the material within the metal plate is plastically flowed toward the plug body, thereby joining the plug and the metal plate. Additionally, at the end of the plug facing the flange portion, a pressure member (punch) is inserted into the lower metal plate surrounding the plug, causing the metal plate material to plastically flow toward the surface of the plug body, thereby applying tightening stress to the plug and joining the lower metal plate and the plug. As a result, the two metal plates are joined through the plug. On the other hand, when multiple grooves are provided in the plug, the punch stroke is usually small, about 1 mm or less, because the spatial volume of the grooves through which the plate material flows is small, and there is no relative movement between the plate material and the plug, resulting in high precision of the joined product. Furthermore, because the plastic flow at the joining part is deformation under compressive stress, there is a low possibility of defects such as cracks occurring in the plate material. For this reason, it is also possible to use work-hardened materials or tempered materials with poor ductility as the soft material. It should be noted that, as is common with mechanical bonding methods, bonding is possible even if the laminate materials are dissimilar. [Brief explanation of the drawing] 【0014】 [Figure 1] This is a partial cross-sectional view of a metal plate joined by the first embodiment of the metal plate joining method according to the present invention. [Figure 2] Figure 1 is a process diagram illustrating an embodiment of the metal plate joining method. Figure 2(a) is a partial cross-sectional view showing the process of inserting the plug flange into the first metal plate, and Figure 2(b) is a partial cross-sectional view showing the process of forming pressure marks (punch marks) on the second metal plate at the end opposite the flange. [Figure 3] Figure 1 is a process diagram illustrating another implementation step in the metal plate bonding method shown. [Figure 4] This is a partial cross-sectional view of a plug used in a second embodiment of the metal plate bonding method according to the present invention. [Figure 5] This is a partial cross-sectional view of a metal plate joined according to a second embodiment of the present invention using the plug shown in Figure 4. [Modes for carrying out the invention] 【0015】 Hereinafter, preferred embodiments of the present invention will be described based on the drawings. FIG. 1 shows a partial cross-sectional view of a metal plate joined by a first embodiment of the metal plate joining method of the present invention. The first metal plate 20 and the second metal plate 30 are laminated, and both metal plates are joined by a plug 1 inserted into through holes 21 and 31 penetrating each metal plate. The plug body 11 is press-fitted into the first metal plate 20 so that the surface of the flange portion 12 becomes flush with the surface of the first metal plate 20 by pressing from above the flange portion 12 having a larger diameter than the plug body 11 with a pressure plate or the like. Further, a plurality of plug grooves 14 and 15 are formed on the plug body 11 near the flange portion 12 and near the tip portion 13 of the plug, respectively. Around the tip portion 13 of the plug on the lower surface of the second metal plate 30, a recess as a punch mark 32 is formed by pressing in the thickness direction of the second metal plate 30 with a pressing member (such as a punch). This figure shows the state after the metal plate joining step by the plug 1, but the member of the first metal plate 20 below the flange portion 12 has entered the plug groove 14 due to plastic flow. Also, at the tip portion 13 of the plug, the member of the second metal plate 30 above the punch mark 32 has entered the plug groove 15. Thereby, the first metal plate 20 and the second metal plate 30 are firmly joined via the plug 1. 【0016】 The manufacturing process for this embodiment will be described. FIG. 2(a) shows the first step, where the first metal plate 20 and the second metal plate 30 are laminated so that the positions of the through holes 21 and 31 coincide, the plug 1 is inserted, and the surface of the flange portion 12 of the plug 1 is pressed by a pressure plate 100 from above. By this operation, the plug 1 is press-fitted into the first metal plate 20 so that the surface of the flange portion 12 becomes flush with the surface of the first metal plate 20. At this time, as the flange portion 12 penetrates into the first metal plate 20, the members around the through hole 21 plastically flow and press the plug body 11, and a part enters the plug groove 14, and the first metal plate 20 and the plug 1 are joined. In this embodiment, a cylindrical quenched and tempered steel (HRC30) with a diameter of 10 mm is used as the plug 1, and a steel plate (SPCE) with a thickness of 1.4 mm is used as the first metal plate 20. 【0017】 Figure 2(b) shows the second step. The laminate of the first metal plate 20 and the second metal plate 30 is turned upside down, and the second metal plate 30 around the tip of the plug 13 is pressed by a punch 200 with a hollow portion 201 provided in the center. By this operation, the punch tip 202 enters into the second metal plate 30 to form a recess as a punch mark 32. At this time, the member of the second metal plate 30 below the punch mark 32 plastically flows to press the plug body 11, and a part enters into the plug groove 15 to couple the second metal plate 30 and the plug 1. As a result, the first metal plate 20 and the second metal plate 30 are firmly coupled via the plug 1. In this embodiment, an aluminum plate (A5052-O) with a thickness of 2 mm was used as the second metal plate 2. 【0018】 Figure 3 shows another manufacturing process of the first embodiment according to the present invention shown in FIG. 1. In FIG. 2, the bonding was performed in two steps, but in this process, the pressing of the flange portion 12 of the plug 1 by the press plate 100 and the pressing of the second metal plate 30 around the tip of the plug 13 by the punch 200 are performed simultaneously. This shortens the time of the manufacturing process and leads to cost reduction. 【0019】 Figure 4 is a partial cross-sectional view of a plug used in the second embodiment of the metal plate bonding method according to the present invention. The upper half is the same as the plug used in the first embodiment shown in FIG. 1, but the difference is that a small-diameter portion 16 is provided at the tip of the plug 13. As a result, a step portion 18 is formed in the middle of the plug body 11. The step portion 18 serves as a flange for the small-diameter portion 16. A plug groove 17 is formed below the step portion 18. 【0020】 Figure 5 is a partial cross-sectional view of a metal plate joined according to a second embodiment of the present invention using the plug shown in Figure 4. The manufacturing process of the second embodiment will be explained using this figure. In the first embodiment, through holes of the same diameter were formed in the first metal plate and the second metal plate. In this embodiment, however, a through hole 21 with approximately the same diameter as the plug body 11 is formed in the first metal plate 20, and a through hole 31 with approximately the same diameter as the small diameter portion 16 is formed in the second metal plate 30. The first metal plate 20 and the second metal plate 30 are stacked so that the positions of their respective through holes 21 and 31 are the same, and the plug 1 is inserted. The surface of the flange portion 12 of the plug 1 is then pressed from above with a pressure plate so that the surface of the flange portion 12 is aligned with the surface of the first metal plate 20. At this time, the flange portion 12 penetrates into the first metal plate 20, and the material surrounding the through hole 21 undergoes plastic flow, pressing against the plug body 11, with a portion entering the plug groove 14, thereby bonding the first metal plate 20 and the plug 1. Simultaneously, the stepped portion 18 penetrates into the second metal plate 30, and the material surrounding the through hole 31 undergoes plastic flow, pressing against the plug body 11, with a portion entering the plug groove 17, thereby bonding the second metal plate 30 and the plug 1. As a result, the first metal plate 20 and the second metal plate 30 are firmly bonded together via the plug 1. 【0021】 The metal plate joining method according to the present invention, as shown in the above embodiment, is characterized by the fact that by applying pressure and pressing the surface of the soft material with the flange portion provided on the plug, the intermediate step portion of the plug, or the tip of the punch, the soft plate material is made to flow into the plug groove provided on the hard material plug, and a strong bond is formed by utilizing the resistance force of the shear deformation of the material. In addition, the soft plate material is pressed with high pressure against the smooth part of the plug, and the tightening pressure (residual stress) is maintained even after the pressure applied by the punch is released, and this frictional resistance force of tightening is utilized. Furthermore, because the spatial volume of the plug groove through which the plate material flows is small, the punch stroke is usually small, about 1 mm or less, and there is no relative movement between the plate material and the plug, resulting in high precision of the joined product. Moreover, because the plastic flow of the joint is deformation under compressive stress, there is a low possibility of defects such as cracks occurring in the plate material. For this reason, it is also possible to use work-hardened materials or tempered materials with poor ductility as the soft material. It should be noted that, as is common with mechanical bonding methods, bonding is possible even if the laminate materials are dissimilar. [Explanation of Symbols] 【0022】 1 plug 11 Plug body 12. Guard section 13. Plug tip 14 plug grooves 15 plug grooves 16 Small diameter section 17 Plug grooves 18 Step section 20 First metal plate 21 Through hole 30 Second metal plate 31 Through hole 32 punch marks 100 Pressure Plate 200 punches 201 Hollow part 202 Punch tip

Claims

[Claim 1] Through holes of approximately the same diameter are provided in both the first metal plate and the second metal plate, and the first metal plate is laminated on the second metal plate so that the through holes overlap. A plug having a main body with a diameter approximately equal to the diameter of the through hole and a flange on one side that is larger than the diameter of the through hole is inserted into the through hole. The upper surface of the first metal plate, including the plug, and the lower surface of the second metal plate, around the bottom surface of the plug are pressurized. The flange portion is inserted into the first metal plate, and at the end of the plug facing the flange portion, the pressurizing member is inserted into the second metal plate surrounding the plug, A method for joining metal plates, characterized by joining the first and second metal plates through the plug by causing each metal plate material to undergo plastic flow toward the surface of the plug body, thereby applying a tightening stress to the plug. [Claim 2] The metal plate joining method according to claim 1, characterized in that a plurality of grooves in the circumferential direction are provided on the main body surface of the plug, near the flange, and near the plug end facing the flange. [Claim 3] Through holes are provided in both the first and second metal plates such that the diameter of the through hole in the first metal plate is greater than the diameter of the through hole in the second metal plate, and the first metal plate is laminated on the second metal plate so that the through holes overlap. A plug is inserted into the through hole, having a main body portion with a stepped portion formed such that the upper part is approximately equal in diameter to the through hole of the first metal plate and the lower part is approximately equal in diameter to the through hole of the second metal plate, and a flange portion at the upper end that is larger than the diameter of the upper part of the main body. By applying pressure to the upper surface of the first metal plate, including the plug, and the lower surface of the second metal plate, the flange portion is forced into the first metal plate and the stepped portion of the plug into the second metal plate, thereby causing the metal plate material around the flange portion and the stepped portion to plastically flow toward the main body surface of the plug, thereby applying tightening stress to the plug. A method for joining metal plates, characterized in that the first and second metal plates are joined together as a result. [Claim 4] The metal plate joining method according to claim 3, characterized in that a plurality of grooves in the circumferential direction are provided on the main body surface of the plug, near the flange portion, and near the stepped portion. [Claim 5] The metal plate bonding method according to any one of claims 1 to 4, characterized in that the plug has a higher hardness than either of the first or second metal plates.

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