Self-piercing riveting device and controlling method thereof

Abstract

A self-piercing riveting device and a method for controlling the same are provided. The self-piercing riveting device comprises: an anvil head having a forming surface; a punch facing the anvil head; a vibrating member coupled to the anvil head; and a vibration sensor configured to measure the vibration of the vibrating member.

Description

Technology Field

[0001] The present invention relates to a self-piercing riveting device and a method for controlling the same. Background Technology

[0002] Generally, heterogeneous or multi-material joining refers to the joining or combination of multiple materials that differ in type, physical properties, and characteristics. In a broader sense, heterogeneous material joining can be used to encompass joining techniques, forming techniques, and surface treatment techniques between materials. Recently, as there is a demand for lighter and higher-strength materials, various materials other than conventional metals are being utilized, and accordingly, diverse research related to heterogeneous material joining technology is being conducted.

[0003] However, since existing fusion-based welding technologies for steel (e.g., resistance spot welding, arc welding, laser welding, etc.) cannot be applied to joining dissimilar materials with different physical properties, non-welding techniques such as adhesive bonding and mechanical joints are being proposed.

[0004] Mechanical fastening technology is a general term for technologies that mechanically join dissimilar materials using separate fastening members while maintaining physical boundaries between the joining materials. Traditional mechanical fastening methods, such as bolt-nut joining and blind riveting, have the disadvantage of being complex processes and difficult to automate because they require prior hole machining of the joining members and alignment between holes and between holes and rivets. Therefore, mechanical fastening methods that do not presuppose hole machining, such as self-piercing riveting (SPR), flow drill screwing (FDS), and clinching, have recently gained popularity. The problem to be solved

[0005] Self-piercing riveting (SPR) is a mechanical fastening technology and one of the representative form-based spot joining techniques. It is a widely used mechanical fastening method because it can achieve very strong bond strength with minimal material deformation and a relatively simple process.

[0006] Self-piercing riveting offers high productivity due to its simpler process and ability to be automated compared to bolt-nut fastening, as well as advantages such as relatively low thermal deformation and applicability to dissimilar and coated materials. Furthermore, it is considered the most realistic alternative for spot joining of dissimilar materials because it can be used to join non-ferrous metals and steel, offers excellent bonding strength, and is environmentally friendly.

[0007] Self-piercing riveting is performed by inserting a rivet of a special shape into one side of two materials to be joined. In self-piercing riveting, the rivet penetrates the upper material, and the upper and lower materials are strongly interlocked and joined by the shape deformation of the rivet, called flaring, and the resulting shape deformation of the lower material according to the shape of the forming band (or anvil head) located below the lower material.

[0008] However, conventional self-piercing riveting devices carry the risk of fastening defects caused by the material condition of the joined materials or misalignment. One of the critical elements of mechanical fastening technology is the evaluation of the fastening quality. Particularly in the case of self-piercing riveting, once the fastening is completed, there is a lack of suitable means to evaluate the bonded state—that is, the fastening quality—without destroying the connection. Especially from the perspective of automating mechanical fastening processes, there is a significant need for non-destructive inspection of the fastening site during or immediately after the process, as well as for real-time monitoring; accordingly, various technological developments are being made.

[0009] Accordingly, another problem that the present invention aims to solve is to provide a mechanical fastening device or a heterogeneous material joining device, specifically a self-piercing riveting device, capable of monitoring or evaluating the quality of mechanical fastening using a new method different from the conventional one.

[0010] Another problem that the present invention aims to solve is to provide a method for controlling the above-mentioned mechanical fastening device, dissimilar material joining device, or self-piercing riveting device, or a method for evaluating or monitoring the mechanical fastening process.

[0011] The problems of the present invention are not limited to the technical problems mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0012] A heterogeneous material joining device according to one embodiment of the present invention for solving the above problem includes: an anvil head having a molding surface; a punch facing the anvil head; and a vibration sensor.

[0013] In some embodiments, the heterogeneous material joining device may further include a vibrating member coupled to the anvil head.

[0014] At this time, the vibration sensor may be configured to measure the vibration of the vibration member.

[0015] In some embodiments, the heterogeneous material joining device may further include a pump unit.

[0016] Additionally, the anvil head may have one or more injection holes formed on the molding surface, which are injection holes for injecting gas supplied by the pump unit.

[0017] The diameter of the above injection hole may be 2 mm or less.

[0018] In addition, the above-mentioned vibrating member may be in the shape of a pin, rod, or plate.

[0019] In some embodiments, the heterogeneous material joining device further includes an anvil frame that supports the anvil head, and at least the vibrating member may be disposed in the internal space of the anvil frame.

[0020] A control method for a heterogeneous material joining device according to one embodiment of the present invention for solving any other problem above is a method performed by a device including at least one processor, comprising lowering a punch, measuring the vibration of a vibrating member connected to an anvil head, and raising the punch.

[0021] In some embodiments, the control method of the heterogeneous material joining device may further include injecting gas through an injection hole formed on the molding surface of the anvil head and measuring the injection pressure of the gas.

[0022] Additionally, the control method may further include determining the quality of the bond based on the measured vibration, and / or further include determining the quality of the bond based on the measured pressure.

[0023] The above control method allows unit processes to be performed continuously, and within any unit process, the measurement of the injection pressure can be performed at least during the time between the lowering phase and the rising phase of the punch.

[0024] Additionally, within the above unit process, the injection of the gas can be performed at least before the downward step of the punch.

[0025] A program according to one embodiment of the present invention for solving any other problem described above is combined with a computing device and configured to perform instructions including lowering a punch, measuring vibration, and raising a punch.

[0026] Here, the above program may be a program recorded on a recording medium.

[0027] In addition, the above program may be configured to be stored or loaded in memory and performed or executed by a processor.

[0028] Specific details of other embodiments are included in the detailed description. Effects of the invention

[0029] According to embodiments of the present invention, the quality of the mechanical fastening process can be determined based on the impact transmitted to the anvil head and the vibration of the anvil head caused thereby during the process of pressing a rivet onto a joined material.

[0030] Furthermore, the quality of the mechanical fastening process can be determined based on the pressure of the air injected through the air injection hole formed in the anvil head.

[0031] The effects according to the embodiments of the present invention are not limited to those exemplified above, and a wider variety of effects are included in this specification. Brief explanation of the drawing

[0032] FIG. 1 is a cross-sectional schematic diagram of a heterogeneous material joining device according to one embodiment of the present invention. Figure 2 is a cross-sectional schematic diagram showing an enlarged view of the process area of ​​Figure 1. Figure 3 is a hardware configuration diagram of the heterogeneous material joining device of Figure 1. FIG. 4 is a flowchart illustrating a control method for a heterogeneous material bonding device according to one embodiment of the present invention. Figures 5 to 9 are cross-sectional schematic diagrams showing the process according to the control method of Figure 4. Specific details for implementing the invention

[0033] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms. The embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0034] Furthermore, the scope of patent claims is not a matter describing the technical content that constitutes the substance of the invention, but rather a matter indicating what scope is claimed as a right based on the technical configuration disclosed in the detailed description of the invention. Therefore, it is somewhat inevitable that the scope of patent claims is composed of abstract higher-level concepts that include the technology disclosed in the detailed description of the invention, and if a person skilled in the art can understand the technical configuration, combination, and functional effects belonging to the scope of patent claims through the entire specification, then the scope of patent claims should be considered to be supported by the detailed description of the invention.

[0035] That is, various modifications may be made to the embodiments presented in the present invention. The embodiments described below are not intended to limit the forms of practice and should be understood to include all modifications, equivalents, and substitutions thereof.

[0036] If any term described in this specification is to be used with a specific meaning, such meaning may be defined and used, and it should be interpreted accordingly. Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0037] In this specification, "and / or" includes each of the mentioned items and all combinations of one or more. Also, the singular form includes the plural form unless specifically stated otherwise in the text. As used in this specification, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the mentioned components. A numerical range indicated by "to" indicates a numerical range that includes the values ​​listed before and after it as a lower and upper limit, respectively. "Approximately" or "about" means a value or numerical range within 20% of the value or numerical range listed after it.

[0038] In this specification, ordinal modifiers such as 'first component,' 'second component,' and 'first-1 component' are used merely to distinguish one component from another when referring to components. Accordingly, the first component referred to below may be referred to as the second component within the scope of the technical concept of the present invention. For example, what is referred to as the first component in one embodiment may be referred to as the second component in another embodiment. Furthermore, it goes without saying that what is referred to as the first component in the description of the invention may be referred to as the second component in the claims.

[0039] The size, thickness, width, length, etc., of the components depicted in the drawings may be exaggerated or reduced for convenience and clarity of explanation, so the present invention is not limited to the depicted form.

[0040] Spatially relative terms such as 'above,' 'upper,' 'on,' 'below,' 'beneath,' and 'lower' may be used to facilitate the description of the relationship between one element or component and another, as illustrated in the drawings. When used in addition to the directions depicted in the drawings, spatially relative terms should be understood as encompassing different orientations of the elements. For example, if an element depicted in the drawing is flipped, an element described as being 'below' or 'beneath' another element may be placed 'above' of that other element. Therefore, the exemplary term 'below' may encompass both the downward and upward directions.

[0041] The present invention will be described in detail below with reference to the attached drawings.

[0042] FIG. 1 is a schematic cross-sectional view of a heterogeneous material joining device according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an enlarged process area of ​​FIG. 1. FIG. 3 is a hardware configuration diagram of the heterogeneous material joining device of FIG. 1.

[0043] Referring to FIGS. 1 to 3, the heterogeneous material joining device (10) (or mechanical fastening device, or self-piercing riveting device) according to the present embodiment includes a frame (100), a punch unit (200), and an anvil unit (300), and may further include a vibration member (400), a vibration sensor (450), and a pump unit (500).

[0044] The frame (100) may be provided in a shape approximately like the letter 'C', having a first end and a second end facing each other. A punch unit (200) may be disposed on the first end of the frame (100), and an anvil unit (300) may be disposed on the second end. That is, the frame (100) may be configured to support the punch unit (200) and the anvil unit (300).

[0045] The heterogeneous material joining device according to the present embodiment may be a self-piercing riveting device. In this case, a workpiece (not shown) may be placed between a punch unit (200) and an anvil unit (300), and a rivet (R) may be inserted into the workpiece using the punch unit (200). In order to maintain a rigid distance between the punch unit (200) and the anvil unit (300) during the pressing process of the rivet (R), the frame (100) may be made of a material with high strength and rigidity, such as a metal material.

[0046] The punch unit (200) may include a clamp (230) (or punch housing, or rivet housing) and a punch (210). The clamp (230) has an empty internal space, and a punch (210) and a rivet (R) may be placed in the internal space. With the frame (100) fixed and the anvil head (310), which will be described later, fixedly positioned on the frame (100), the clamp (230) may be configured to be vertically movable. As the clamp (230) descends and the distance to the anvil head (310) decreases, the workpiece located between them is fixed or clamped, and as the clamp (230) rises and the distance to the anvil head (310) increases, the fixation of the workpiece may be released.

[0047] The punch (210) may be configured to be able to move up and down within the empty internal space of the clamper (230). At this time, the movement of the punch (210) may be independent of the movement of the clamper (230). A rivet (R) may be placed at the bottom of the punch (210). The rivet (R) includes a head and a shank, and the head of the rivet (R) may be positioned to face the punch (210). The punch (210) may move down along the internal space of the clamper (230) and insert the rivet (R) into the workpiece (not shown).

[0048] The anvil unit (300) may include an anvil head (310) and an anvil frame (330). The anvil frame (330) may be fixedly positioned on the frame (100). The anvil frame (330) may support the anvil head (310) so that the position of the anvil head (310) is not displaced despite repeated and strong impacts applied to the anvil unit (300). In an exemplary embodiment, the anvil frame (330) has an empty internal space, and a vibration sensor (450), etc., may be placed in the internal space. This will be described later.

[0049] The anvil head (310) (or forming table, or anvil die) may be spaced apart from the punch unit (200), specifically the punch (210). The upper surface of the anvil head (310) may have a forming surface (310s) having a groove (or concave groove). As in a known self-piercing riveting process, the rivet (R) is inserted into or at least partially penetrates the workpiece, and the shank and lower piece of the rivet (R) may be deformed along the shape of the forming surface (310s) of the anvil head (310). For example, the shank of the rivet (R) may spread out or flare along the shape of the forming surface (310s) of the anvil head (310).

[0050] In an exemplary embodiment, the anvil head (310) has a head air passage (310f) (or head fluid passage) formed in its internal space, and the head air passage (310f) may be connected to the molding surface (310s) to form an air injection hole (310h) (or air discharge hole, or air injection hole, or fluid hole). That is, the molding surface (310s) may be provided with an air injection hole (310h). The air injection hole (310h) may be provided as one or multiple holes. If multiple air injection holes (310h) are provided, it goes without saying that a head air passage (310f) connected to each air injection hole (310h) may be provided.

[0051] As described above, the molding surface (310s) having an uneven structure of the anvil head (310) can contribute to the shank flaring of the rivet (R). The air injection hole (310h) may be located in a concave portion of the molding surface (310s). In this case, if the air injection hole (310h) is excessively large, it may affect the flaring of the shank, i.e., shape deformation. In this regard, the upper limit of the size of the air injection hole (310h) may be about 3.0 mm, or about 2.0 mm, or about 1.5 mm, or about 1.0 mm. If the size of the air injection hole (310h) is excessively large, it may cause unintended flaring. The lower limit of the size of the air injection hole (310h) may be considered in terms of smooth air injection and measurement of air pressure through it, and may be, for example, about 0.5 mm or more. If the air injection hole (310h) is approximately circular in shape, the size of the air injection hole (310h) can be understood as the diameter of the circle. Or, if the air injection hole (310h) is not circular in shape, for example, elliptical, distorted circle, or polygonal shape, the size of the air injection hole (310h) can be understood as the diameter of an equivalent circle.

[0052] The head air passage (310f) formed in the anvil head (310) may be fluidly connected to the frame air passage (330f) (or frame fluid passage) of the anvil frame (330). If the anvil frame (330) has an empty internal space, the frame air passage (330f) may be formed by penetrating the wall of the anvil frame (330). The frame air passage (330f) may be fluidly connected to an air nozzle (550) (or fluid nozzle) and a pump unit (500). The pump unit (500) may be provided to inject or discharge fluids such as air or other types of gases. FIG. 2 illustrates a case where the pump unit (500) is placed in the internal space of the anvil frame (330) for convenience of explanation, but the present invention is not limited thereto, and in other embodiments, the pump unit (500) may be placed in the internal space of the frame (100) or placed outside the frame (100). In this case as well, the air nozzle (550) is further extended and fluidly connected to the frame air passage (330f). The fluid, such as air supplied or blown by the pump unit (500), can be injected or discharged through the air injection hole (310h) formed on the molding surface (310s) of the anvil head (310). This will be described later.

[0053] In an exemplary embodiment, the anvil head (310) may be positioned to partially penetrate the wall of the anvil frame (330). A vibrating member (400) may be fixedly positioned on the anvil head (310). For example, the vibrating member (400) may be fixedly attached to the bottom of the anvil head (310). The vibrating member (400) may be configured to exhibit vibration characteristics in response to an impact applied to the anvil head (310). For example, the vibrating member (400) may have the shape of a thin rod, a pin with a tip, or a plate, but the present invention is not limited thereto. As described below, the vibrating member (400) may be provided for determining the quality of a heterogeneous material joining process, namely a self-piercing riveting process. At this time, the material, shape, length, thickness, etc. of the vibrating member (400) may be selected so that the difference in vibration characteristics of the vibrating member (400) according to the quality may be highlighted. For example, the vibration pattern of the vibrating member (400) may vary depending on the type of material to be joined, the material properties of the lower piece and the upper piece, the size of the pieces, the pressure applied by the punch (210), and the resulting impact amount, and the material, shape, length, thickness, etc. of the vibrating member (400) may be selected in consideration of this. In addition, the material, shape, length, thickness, etc. of the vibrating member (400) may be selected so that after the impact applied by the punch (210) is transmitted to the vibrating member (400) and causes vibration, the vibrating member (400) does not maintain the vibrating state for an excessively long time and the vibration is stopped. As a non-limiting example, it may be configured so that the vibration subsides within about 1 second or about 0.5 seconds after the impact is applied.

[0054] Additionally, the heterogeneous material bonding device (10) may be equipped with a vibration sensor (450). The vibration sensor (450) may be configured to collect the vibration of the vibrating member (400) as detection data. For example, the physical properties detected by the vibration sensor (450) may be the vibration frequency (i.e., frequency) and amplitude of the vibrating member (400), but the present invention is not limited thereto. Although FIG. 2 illustrates the vibration sensor (450) and the vibrating member (400) facing each other at a distance, the present invention is not limited thereto, and depending on the operation method of the vibration sensor (450), the vibration sensor (450) may be in contact with the vibrating member (400) or fixedly positioned on the vibrating member (400). Since the operation method of the vibration sensor (450) may utilize a known method, a detailed description is omitted.

[0055] The raising and lowering of the aforementioned punch unit (200), namely the punch (210) and clamper (230), and the operation of the pump unit (500) and vibration sensor (450) can be electronically controlled. To this end, the heterogeneous material joining device (10) may further include a processor (910), memory (920), and storage (930).

[0056] The processor (910) (or control unit, or controller) may implement operations and / or functions related to the method according to the present invention based on instructions according to software that implements the control method according to the present invention loaded in memory (920). That is, the processor (910) may be understood as an entity that performs or executes a program. For example, it may execute software to control hardware components and / or software components connected to the processor (910) and may perform data processing or calculations. That is, as part of the data processing or calculation, the processor (910) may store commands or data received from other components in memory (920), process commands or data stored in memory (920), or store result data in memory (920). The processor (910) and / or memory (920), etc., may also be referred to as a control unit.

[0057] The processor (910) may be any known one, but may be implemented through, for example, an ASIC (Application-Specific Integrated Circuit), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), a processor, a controller, a microcontroller, a microprocessor, or other chipset, logic circuit and / or data processing device.

[0058] Software or a program residing in memory (920) or stored in storage (930) may be a computer program recorded on a recording medium to execute the control method described below. The computer program may be a program that is readable and can be executed in combination with a computer, stored on a storage medium.

[0059] The memory (920) can store various data used in at least one component. The data may include input data or output data for software and related commands. The memory (920) may be implemented through Read-Only Memory (ROM), Random Access Memory (RAM), flash memory, memory card, storage medium and / or other storage device.

[0060] Memory (920) can load the computer program from storage (930). Storage (930) can store application programming interfaces (APIs), libraries, resource files, etc., necessary for the execution of software in which the control method according to the present invention is implemented. It can also store software and databases in which the method is implemented. It will be possible to understand the contents of various databases required to perform operations and / or functions related to the method according to the present invention described below.

[0061] In the case of implementation by firmware or software in the control method described below, it may be implemented in the form of modules, codes, code segments, procedures, functions, etc., containing instructions that perform the described functions or operations, and may be recorded on a recording medium readable through various computer means. Here, the recording medium may include program instructions, data files, data structures, etc., either individually or in combination. In this case, each component on the configuration diagram or block diagram may refer to a module, segment, or part of code containing one or more executable instructions for executing a specific logical function. Therefore, it is obvious that the function provided by a component on the configuration diagram or block diagram may be implemented by a plurality of more subdivided components, or that a plurality of components on the configuration diagram or block diagram may be implemented by a single integrated component. That is, within the scope of the purpose of the present invention, each component may operate by selectively combining one or more components. Furthermore, all components may each be implemented as a single independent piece of hardware, or a part or all of each component may be selectively combined to be implemented as a computer program having a program module that performs some or all of the combined functions on one or more pieces of hardware. The codes and code segments constituting the computer program can be easily inferred by a person skilled in the art belonging to the technical field of the present invention.

[0062] In this specification, program instructions recorded on a recording medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in the art of computer software. For example, a recording medium includes magnetic media such as hard disks, floppy disks, and magnetic tapes; optical media such as CD-ROMs (Compact Disk Read Only Memory) and DVDs (Digital Video Disks); magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions may include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. Such hardware devices may be configured to operate as one or more software to perform the operation of the present invention, and vice versa.

[0063] The various hardware components of FIG. 3 constituting the aforementioned heterogeneous material bonding device (10) are connected via a data bus, and data can be transmitted between each component via the data bus.

[0064] Hereinafter, a control method for a heterogeneous material joining device (10) according to the present embodiment, or a method for joining heterogeneous materials using the same, i.e., a self-piercing riveting process method, will be described. Here, the control method for the heterogeneous material joining device (10) may be understood as a method for evaluating or monitoring the self-piercing riveting process.

[0065] FIG. 4 is a flowchart illustrating a control method for a heterogeneous material joining device according to an embodiment of the present invention. FIGS. 5 to 9 are schematic cross-sectional diagrams illustrating a process according to the control method of FIG. 4.

[0066] First, referring further to FIG. 4, the control method of the heterogeneous material joining device (10) according to the present embodiment, or the command module executed by the processor of the heterogeneous material joining device, includes the step of lowering the punch unit (200) to clamp (S200), the step of inserting a rivet (R) into the workpiece (P1, P2) (S300), and the step of raising the punch unit (200) to release (S400), and may further include the step of blowing air (S100). Below, each step or instruction will be described.

[0067] First, the step of injecting air (S100) can be performed by a pump unit (500). As previously described, the pump unit (500) is fluidly connected to an air nozzle (550), a frame air passage (330f), and a head air passage (310f), and the air supplied by the pump unit (500) can be injected through an air injection hole (310h). In this embodiment, the pump unit (500) may be configured to also function as an air pressure measuring sensor. For example, the pump unit (500) may be understood to include an air pressure measuring sensor or a pressure measuring sensor. That is, when the air injection hole (310h) is exposed to the atmosphere and air is injected in an atmospheric pressure atmosphere, when air is injected while the space surrounding the air injection hole (310h) is sealed, and furthermore when air is injected while the air injection hole (310h) is blocked, the pump unit (500) can collect the injection pressure as detection data and measure the difference in injection pressure in each case.

[0068] FIG. 5 illustrates a state in which a first piece (P1) (or first workpiece, or first plate, or upper piece) and a second piece (P2) (or second workpiece, or second plate, or lower piece) are interposed between a punch unit (200) and an anvil unit (300), such as a positioning state. In the state of FIG. 5, the pump unit (500) can start spraying air.

[0069] Next, referring further to FIG. 6, the clamper (230) of the punch unit (200) can be lowered to securely interpose the first piece (P1) and the second piece (P2) between the bottom of the clamper (230) and the top of the anvil head (310) (S200). This state may be a clamping state.

[0070] At this stage, the pump unit (500) may still be in a state of injecting air. For example, after the pump unit (500) starts injecting air, it may maintain the state of injecting air at a constant intensity or flow rate. As the second piece (P2) comes into close contact with the anvil head (310), the space between the second piece (P2) and the molding surface (310s) is approximately sealed, and accordingly, the air injection pressure of the pump unit (500) may be slightly increased. Although not shown in a cross-sectional view, the concave groove of the molding surface (310s) may be approximately annular or donut-shaped in a planar view.

[0071] Referring further to FIG. 7, when the clamper (230) is lowered and clamped, the punch (210) is lowered to bring the shank of the rivet (R) into contact with the first piece (P1), and furthermore, the rivet (R) can be inserted into at least the first piece (P1) (S310). That is, this step can be understood as a piercing step.

[0072] As previously explained, the punch (210) strikes the rivet (R) and provides a very strong impact, thereby allowing the rivet (R) to be inserted into the first piece (P1). The impact provided by the rivet (R) is transmitted to the first piece (P1) and the second piece (P2), as well as to the anvil head (310), and the vibration member (400) coupled and fixed to the anvil head (310) can vibrate. The vibration sensor (450) can measure the vibration of the vibration member (400) (S320).

[0073] At this stage, the pump unit (500) may still be in a state of injecting air. For example, after initiating the injection of air, the pump unit (500) may maintain the state of injecting air at a constant intensity or flow rate. As illustrated in FIG. 7, as the rivet (R) pressurizes and deforms the first piece (P1) and / or the second piece (P2), the space between the second piece (P2) and the molding surface (310s) is reduced, and accordingly, the air injection pressure detected by the pump unit (500) may be further increased.

[0074] Referring further to FIG. 8, the punch (210) descends further so that the rivet (R) penetrates the first piece (P1) and is inserted into the second piece (P2), and its shape can be deformed. For example, this step can be understood as a flaring step. The rivet (R) is deformed according to the irregular shape of the predetermined molding surface (310s), and the second piece (P2), which is pressed by the rivet (R), can also be elastically deformed according to the irregular shape of the molding surface (310s).

[0075] The steps of FIG. 7 and FIG. 8 described above are performed very instantaneously and continuously, and the impact provided by the punch (210) vibrates the vibrating member (400), and the vibration sensor (450) can still measure the vibration state of the vibrating member (400).

[0076] At this stage, the pump unit (500) may still be in a state of injecting air. For example, after initiating the injection of air, the pump unit (500) may maintain the state of injecting air at a constant intensity or flow rate. As illustrated in FIG. 7, as the rivet (R) pressurizes and deforms the first piece (P1) and / or the second piece (P2), the space between the second piece (P2) and the molding surface (310s) may be further reduced, or the lower surface of the second piece (P2) may be in complete contact with the molding surface (310s) and block the air injection hole (310h). Accordingly, the air injection pressure detected by the pump unit (500) may be greatly increased. As a non-limiting example, a peak-shaped injection pressure may be observed.

[0077] Referring further to FIG. 9, the clamper (230) is raised to release the clamping state (S400). This state may be a releasing state. The first piece (P1) and the second piece (P2), which were fixed between the anvil head (310) and the clamper (230), may be joined by a rivet (R). In some embodiments, the pump unit (500) may still be in a state of blowing air. For example, as the clamping pressure applied to the first piece (P1) and the second piece (P2) is removed, the space between the second piece (P2) and the molding surface (310s) is opened, and accordingly, the pump unit (500) may blow air in an atmospheric pressure atmosphere. Also, at this stage, the vibrating member (400) may still be in a vibrating state. However, when impact is applied by the punch (210) and a predetermined amount of time elapses, the vibration of the vibration member (400), such as the frequency of vibration, can gradually decrease.

[0078] Although not shown in the drawing, after raising the punch unit (200) (S400), the processor (910) may further perform a step (S500) of determining the quality of the mechanical fastening process.

[0079] The processor (910) can sequentially perform positioning (e.g., FIG. 5), clamping (e.g., FIG. 6), piercing and flaring using a punch (210) (e.g., FIG. 7 and FIG. 8), and releasing (e.g., FIG. 9) of the materials to be joined according to a set process time. In another embodiment, the processor (910) may sequentially perform positioning, clamping, piercing, flaring, and releasing based on image recognition technology.

[0080] Each of the aforementioned processes forms a single unit process, and a continuous process can be performed by changing the position of the workpiece interposed between the punch unit (200) and the anvil unit (300) or by replacing the workpiece (S600) (e.g., moving). Here, the unit process can be described based on any one of the aforementioned detailed processes, excluding the air injection initiation step (S100) (e.g., positioning, clamping, piercing, flaring, releasing, or moving). For example, the period from a clamping step (S200) to just before the next clamping step may be understood as a single unit process, and the period from a releasing step (S400) to just before the next releasing step may be understood as a single unit process. The quality of the process can be determined using the vibration pattern and / or the measurement pattern of the air injection pressure observed in the time flow of such a series of riveting processes.

[0081] Meanwhile, the change in position or replacement (S600) of the materials to be joined may be performed by a device that holds the materials to be joined. The step of changing the position or replacement (S600) of the materials to be joined may be performed using the processor (910) of the heterogeneous material joining device (10), or it may be performed by a separate computing device distinct from the heterogeneous material joining device.

[0082] For example, the impact provided by the punch (210) may exhibit a certain vibration pattern depending on the material of the joined material (P1, P2), etc. Here, the vibration pattern may include the maximum vibration frequency of the vibrating member (400), the minimum vibration frequency at a certain point in time, the maximum amplitude, and / or the minimum amplitude at a certain point in time. Accordingly, the processor (910) can compare the vibration pattern of the vibrating member (400) observed over time (according to a series of processes within a unit process) with a pre-stored pattern, and if it deviates from the standard, determine the riveting, i.e., piercing in the corresponding unit process as a defective process.

[0083] Alternatively, in some complementary or alternative embodiments, the vibration member (400) may exhibit a characteristic or unique vibration pattern depending on the process steps over time. For example, the quality of the process may be determined by comparing the difference between the vibration frequency (or other vibration pattern) at the moment of piercing, understood as from the moment the rivet (R) contacts the first piece (P1), and the vibration frequency immediately after flaring.

[0084] Furthermore, the heterogeneous material joining device (10) according to the present embodiment may determine whether there is a defect in the process based on the air pressure or injection pressure measured by the pump unit (500). That is, the processor (910) can compare a pre-stored air injection pressure change pattern with an injection pressure pattern measured over time, and if it deviates from the standard, determine the riveting, i.e., piercing in the corresponding unit process as a defective process.

[0085] To this end, the pump unit (500) or its injection pressure sensor can measure and record the injection pressure at least at a point in time after the lowering phase (S200) of the clamper (230) and / or after the lowering phase (S310) of the punch and / or at least before the raising phase (S400) of the punch (210) or the clamper (230), preferably during the time between the lowering phase (S310) of the punch (210) and the raising phase (S400) of the punch unit (200) (S330).

[0086] As previously explained, the injection pressure may exhibit an increasing or decreasing pattern depending on the relative positional relationship between the second piece (P2) and the molding surface (310s) where the air injection hole (310h) is formed. That is, at the moment before the positioning step, that is, before the clamping step (S200) and / or after the releasing step (S400), the injection pressure is measured at an atmospheric pressure level, and from the clamping step (S200) where the clamper (230) and the first piece (P1) come into contact until the piercing step (S310), the air pressure may increase slightly. As a non-limiting example, the injection pressure may increase linearly with a roughly low slope.

[0087] Additionally, the piercing step, the flaring step (S310), and the subsequent releasing step (S400) are performed instantaneously for a very short period of time, but as the space between the second piece (P2) and the molding surface (310s) is reduced and the air injection hole (310h) is sealed, an air injection pressure such as a peak or impulse shape can be observed. This is because when the riveting process is performed normally, the intended shank flaring occurs, the lower surface of the second piece (P2) is deformed in close contact corresponding to the shape of the molding surface (310s), and the air injection hole (310h) is sealed. If, unlike the example in FIG. 8, the riveting process is not complete and is defective, for example, if the second piece (P2) is not deformed to completely correspond to the irregular shape of the molding surface (310s) and a partially separated space remains between the second piece (P2) and the molding surface (310s), the size of the peak observed in the piercing step or flaring step may be small, the duration of the peak may differ from the reference value, or there may be a difference in the integral value of the peak.

[0088] Although the present invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments of the invention.

[0089] Accordingly, the scope of the present invention should be understood to include modifications, equivalents, or substitutions of the technical concept exemplified above. For example, each component specifically shown in the embodiments of the present invention may be implemented with modifications. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims. Explanation of the symbols

[0090] 10: Dissimilar material joining device 100: Frame 200: Punch Unit 210: Clamper 230: Punch 300: Anvil Unit 310: Anvil Head 330: Anvil Frame

Claims

Claim 1 A heterogeneous material joining device comprising: an anvil head having a molding surface; a punch facing the anvil head; and a pump unit, wherein the anvil head has one or more injection holes formed on the molding surface, and the injection holes for injecting gas supplied by the pump unit. Claim 2 A heterogeneous material joining device according to claim 1, further comprising a vibration sensor; and a vibration member coupled to the anvil head, wherein the vibration sensor is configured to measure the vibration of the vibration member. Claim 3 delete Claim 4 A heterogeneous material joining device according to claim 1, wherein the diameter of the injection hole is 2 mm or less. Claim 5 delete Claim 6 delete Claim 7 A method for controlling a heterogeneous material joining device, comprising: injecting gas through an injection hole formed on the molding surface of an anvil head, performed by a device including at least one processor; measuring the injection pressure of the gas; and lowering and raising a punch. Claim 8 delete Claim 9 A control method according to claim 7, further comprising measuring the vibration of a vibration member connected to an anvil head; and determining the quality of the joint based on the measured vibration. Claim 10 A control method according to claim 7, further comprising determining the quality of the bond based on the measured pressure. Claim 11 In claim 7, the control method is a control method in which a unit process is performed continuously, and within any unit process, the measurement of the injection pressure is performed at least during the time between the lowering phase and the rising phase of the punch. Claim 12 In claim 11, a control method in which, within any unit process, the injection of the gas is performed at least before the downward step of the punch. Claim 13 A program recorded on a recording medium configured to perform instructions including injecting gas into an injection hole formed on the molding surface of an anvil head, detecting the injection pressure of the gas, and operating a punch, combined with a computing device.

Images