Gun arm and joining device

Abstract

This provides a gun arm that is lighter and has improved rigidity. [Solution] The gun arm 100 includes an inner frame portion 110, an outer frame portion 120, and beam portions 131-140. The inner frame portion 110 includes a base portion 111 and first extension portions 112 and second extension portions 113 extending in a second direction from one end and the other end of the base portion 110 in a first direction. When viewed from a third direction perpendicular to the first and second directions, each of the beam portions 131-140 extends away from the central portion C of the base portion 111 in the first direction as it moves from the inner frame portion 110 side toward the outer frame portion 120 side. When viewed from the third direction, the extending direction of each of the beam portions 131-140 is such that the acute angle made with the base portion 111 decreases as the intersections c1-c10 between them and the base portion 111 move away from the central portion C in the first direction.

Description

Technical Field

[0001] The present invention relates to a gun arm and a joining device provided with the same.

Background Art

[0002] Conventionally, various methods for joining a plurality of workpieces to be joined have been known. For example, Japanese Patent Application Laid-Open No. 2014-168805 (Patent Document 1) discloses a joining device for performing friction stir joining, which is an example of the above method. In addition, International Publication No. 2021 / 182444 (Patent Document 2) discloses a joining device for performing solid-phase resistance spot joining, which is another example of the above method. These joining devices are all provided with a pair of joining units that are coaxially arranged opposite to each other and press the plurality of workpieces to be joined so as to be capable of sandwiching them.

[0003] From the viewpoint of improving the working efficiency in these joining methods, for example, as disclosed in the above Patent Document 1, it is conceivable to apply a robot arm to the joining device. In this case, the robot arm will be connected to a gun arm to which the pair of joining units is attached.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, in order to ensure the joining quality in the various joining methods described above, it is important that the pair of joining units are arranged coaxially without causing axial misalignment.

[0006] In this regard, when a load is applied to the object to be joined by the pair of joining units described above, a reaction force of this load is applied to the gun arm. If this causes the gun arm to bend, it may cause axial misalignment in the pair of joining units, which could result in a decrease in the quality of the joint.

[0007] This problem is particularly pronounced when using solid-phase resistance spot bonding, which tends to apply a larger load to the joined objects compared to other bonding methods, or when the gun arm is constructed from a frame or its thickness is reduced in order to lighten the bonding device.

[0008] Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a gun arm that is lightweight while improving rigidity, and a joining device equipped with the same. [Means for solving the problem]

[0009] The gun arm according to the present invention is capable of mounting a first joining unit and a second joining unit, which press together multiple overlapping objects to be joined, so as to face each other in a first direction. The gun arm according to the present invention comprises an inner frame portion constituting an inner circumference, an outer frame portion constituting an outer circumference, and a plurality of beam portions connecting the inner frame portion and the outer frame portion to each other. The inner frame portion has a base portion, a first extension portion, and a second extension portion. The base portion extends along the first direction. The first extension portion extends from one end of the base portion in the first direction along a second direction intersecting the first direction. The second extension portion extends from the other end of the base portion in the first direction along the second direction and is positioned opposite the first extension portion in the first direction with a gap between them. Viewed from the first direction and a third direction perpendicular to the second direction, each of the plurality of beam sections extends away from the center of the base section in the first direction as it moves from the inner frame section towards the outer frame section. Viewed from the third direction, the acute angle between the extending direction of each of the plurality of beam sections and the base section decreases as the intersection of the extending direction and the base section moves away from the center in the first direction.

[0010] By configuring it in this way, it is possible to create a gun arm that is lightweight while also improving rigidity.

[0011] In the gun arm according to the present invention described above, the portion enclosed by two adjacent beam portions among the plurality of beam portions, the inner frame portion, and the outer frame portion may be a hole that penetrates in the third direction.

[0012] This configuration makes it possible to further reduce the weight of the gun arm.

[0013] In the gun arm according to the present invention described above, when viewed from the third direction, the plurality of beam portions may become thicker from the inner frame portion side toward the outer frame portion side.

[0014] By configuring it in this way, the rigidity of the outer frame portion of the gun arm can be improved.

[0015] In the gun arm according to the present invention described above, a robot arm may be connected to the center in the first direction.

[0016] By configuring it in this way, the difference between the amount of deflection that occurs in the part of the gun arm located above the center in the first direction and the amount of deflection that occurs in the part located below the center can be reduced when joining multiple objects to be joined.

[0017] The joining device according to the present invention comprises the gun arm according to the present invention described above, the first joining unit described above, and the second joining unit described above.

[0018] By configuring it in this way, it is possible to create a joining device that has a gun arm that is lightweight while also having improved rigidity.

[0019] The bonding apparatus based on the present invention described above may be used for solid-phase resistance spot bonding. By configuring it in this way, solid-phase resistance spot bonding becomes possible.

[0020] In the bonding apparatus according to the present invention described above, the first bonding unit may have a first pressing shaft for pressing the plurality of objects to be bonded in a plastically deformable manner, and a first electrode arranged around the first pressing shaft for applying a voltage to the plurality of objects to be bonded. The second bonding unit may have a second pressing shaft for pressing the plurality of objects to be bonded in a plastically deformable manner, and a second electrode arranged around the second pressing shaft for applying a voltage to the plurality of objects to be bonded. By configuring in this way, solid-phase resistance spot bonding becomes possible. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a gun arm in which weight reduction is achieved while improving rigidity, and a bonding device including the same.

Brief Description of the Drawings

[0022] [Figure 1] It is a schematic diagram schematically showing a bonding device according to Embodiment 1. [Figure 2] It is a schematic cross-sectional view schematically showing the state in the vicinity of the workpiece during solid-phase resistance spot bonding. [Figure 3] It is a six-view drawing of a gun arm in a state where a first bonding unit and a second bonding unit are attached. [Figure 4] It is a schematic front view for explaining the detailed configuration of the gun arm shown in FIG. 3. [Figure 5] It is a perspective view of a simulation model of Example 1. [Figure 6] It is a six-view drawing of the gun arm of Example 1. [Figure 7] It is a perspective view of the gun arm of Example 1. [Figure 8] It is a six-view drawing of the gun arm of Comparative Example 1. [Figure 9] It is a perspective view of the gun arm of Comparative Example 1. [Figure 10] It is a front view showing the displacement distribution in the Z-axis direction in the gun arms of Example 1 and Comparative Example 1. [Figure 11] It is a table showing the displacement amount in the Z-axis direction at a predetermined position of the gun arms of Example 1 and Comparative Example 1. [Figure 12] It is a front view showing the stress distribution in the gun arms of Example 1 and Comparative Example 1. [Figure 13] It is a six-view drawing of the gun arm of Example 2. [Figure 14] It is a perspective view of the gun arm of Example 2. [Figure 15] It is a six-view drawing of the gun arm of Example 3. [Figure 16]This is a perspective view of the gun arm of Example 3. [Figure 17] This is a schematic diagram illustrating the joining device according to Embodiment 4. [Modes for carrying out the invention]

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated. In the embodiments of the present invention described below, a gun arm used for solid-phase resistance spot bonding and a bonding device equipped therewith will be described as examples.

[0024] (Embodiment 1) Figure 1 is a schematic diagram illustrating the joining device according to Embodiment 1. Figure 2 is a schematic cross-sectional view illustrating the vicinity of the objects to be joined during solid-phase resistance spot joining. Figure 3 is a six-view drawing of the gun arm with the first joining unit and the second joining unit attached. In detail, Figures 3(A) to 3(F) are the front view, rear view, left side view, right side view, top view, and bottom view of the gun arm, respectively (the same applies to Figures 6, 8, 13, and 15, which will be described later). Figure 4 is a schematic front view illustrating the detailed configuration of the gun arm shown in Figure 3. Hereinafter, the overall configuration of the gun arm 100 according to this embodiment and the joining device 1A equipped therewith will be described with reference to Figures 1 to 4.

[0025] In the following explanation, as shown in Figure 1, the left-right direction when viewing the gun arm 100 from the front will also be referred to as the X-axis direction. The front-back direction when viewing the gun arm 100 from the front will also be referred to as the Y-axis direction. Furthermore, the up-down direction when viewing the gun arm 100 from the front will also be referred to as the Z-axis direction.

[0026] The joining device 1A is used for so-called solid-phase resistance spot bonding, which joins multiple objects to be joined together in a solid state at low temperatures without melting them. Specifically, the joining device 1A applies a voltage to multiple objects to be joined that are stacked on top of each other to form softened regions, and then applies a load to the objects in the state where softened regions have been formed to plastically deform these softened regions.

[0027] In this embodiment, plate-shaped objects to be joined 301 and 302 are joined to each other by the joining device 1A. The number of objects to be joined is not limited to two, and may be three or more.

[0028] The joined objects 301 and 302 are made of steel plates, such as high-tensile steel. However, the joined objects 301 and 302 are not limited to being made of steel plates, and may be made of aluminum plates or the like. Furthermore, the joined objects 301 and 302 may be made of dissimilar materials, such as steel plates and aluminum plates.

[0029] As shown in Figures 1 to 3, the joining device 1A comprises a first joining unit 10, a second joining unit 20, a gun arm 100, and a robot arm 200. The first joining unit 10 and the second joining unit 20 are designed to press and clamp multiple objects to be joined that are stacked on top of each other.

[0030] The first bonding unit 10 has a first pressing shaft 11 and a first electrode 12. The first bonding unit 10 is driven in the Z-axis direction by a drive device such as a servo press (not shown). Power is supplied to the first bonding unit 10 from a power supply (not shown) (not shown).

[0031] In this embodiment, the first direction corresponds to the Z-axis direction, the second direction intersecting the first direction corresponds to the X-axis direction, and the third direction perpendicular to the first and second directions corresponds to the Y-axis direction.

[0032] The first pressing shaft 11 has a substantially cylindrical portion. The first pressing shaft 11 causes plastic deformation of the superimposed objects 301 and 302 by pressing them along the Z-axis direction.

[0033] The first electrode 12 has a substantially cylindrical portion. The first electrode 12 is positioned around the first pressurizing shaft 11 such that it is spaced radially away from the first pressurizing shaft 11. The first electrode 12 applies a voltage to the objects to be joined 301 and 302.

[0034] The second bonding unit 20 has a second pressure shaft 21 and a second electrode 22. Power is supplied to the second bonding unit 20 from a power supply (not shown) (not shown).

[0035] The second pressure shaft 21 has a substantially cylindrical portion. The second pressure shaft 21 causes plastic deformation of the superimposed objects 301 and 302 by pressing them along the Z-axis direction.

[0036] The second electrode 22 has a substantially cylindrical portion. The second electrode 22 is positioned around the second pressure shaft 21 such that it is spaced radially away from the second pressure shaft 21. The second electrode 22 applies a voltage to the objects to be joined 301 and 302.

[0037] The material of the first press shaft 11 and the second press shaft 21 is, for example, tungsten carbide. However, the material of the first press shaft 11 and the second press shaft 21 is not particularly limited to tungsten carbide, but may be tool steel, heat-resistant steel, or ceramics, as long as it can press the objects to be joined 301 and 302 in a way that allows for plastic deformation. The material of the first electrode 12 and the second electrode 22 is, for example, copper.

[0038] The first joining unit 10 and the second joining unit 20 are attached to the gun arm 100, so that they are coaxially positioned and facing each other in the Z-axis direction.

[0039] As shown in Figures 1 and 3, the gun arm 100 includes an inner frame portion 110, an outer frame portion 120, and a plurality of beam portions 130. The inner frame portion 110 and the outer frame portion 120 have a roughly C-shape when viewed from the Y-axis direction. The inner frame portion 110 constitutes the inner circumference of the gun arm 100. The outer frame portion 120 constitutes the outer circumference of the gun arm 100.

[0040] The inner frame portion 110 has a base portion 111, a first extension portion 112, and a second extension portion 113. The base portion 111 extends along the Z-axis direction. The first extension portion 112 extends along the X-axis direction from one end 111a of the base portion 111 in the Z-axis direction. The second extension portion 113 extends along the X-axis direction from the other end 111b of the base portion 111 in the Z-axis direction. The first extension portion 112 and the second extension portion 113 are positioned opposite each other with a gap in the Z-axis direction. Note that the extension direction of the first extension portion 112 and the second extension portion 113 does not necessarily have to coincide with the X-axis direction, and may extend along a direction that is appropriately inclined from the X-axis direction.

[0041] The first joining unit 10 is positioned to protrude from the first extension 112 such that its tip faces the second extension 113. The second joining unit 20 is positioned to protrude from the second extension 113 such that its tip faces the first extension 112.

[0042] As a result, a joining space 500 is provided between the first extension 112 and the second extension 113, which is a space in which the objects to be joined 301 and 302 are joined together by the first joining unit 10 and the second joining unit 20.

[0043] As described above, the first joining unit 10 is driven in the Z-axis direction by the drive device. This configures the first joining unit 10 to be movable relative to the second joining unit 20 along the Z-axis direction.

[0044] The outer frame portion 120 is positioned at a distance from the inner frame portion 110, on the opposite side of the joint space 500 when viewed from the inner frame portion 110.

[0045] Multiple beam sections 130 are positioned to bridge the inner frame section 110 and the outer frame section 120, thereby connecting them to one another. In this embodiment, the gun arm 100 includes 10 beam sections 130. The beam sections 130 will be described in detail later.

[0046] Of the gun arm 100, at least a portion of the area enclosed by two adjacent beam sections 130 from among the multiple beam sections 130, and the inner frame section 110 and the outer frame section 120, is a hole 150 that penetrates in the Y-axis direction. By providing multiple holes 150 throughout the gun arm 100 in this way, the weight of the gun arm 100 can be reduced. In this embodiment, the gun arm 100 contains 11 holes 150.

[0047] The gun arm 100 is made of a molded product made of a metal material such as aluminum, aluminum alloy, or stainless steel. The gun arm 100 is formed, for example, by machining a plate-shaped metal member that serves as the raw material.

[0048] A robot arm 200 is connected to the gun arm 100. In this embodiment, the end effector of the robot arm 200 is connected to the center of the gun arm 100 in the Z-axis direction. This reduces the difference between the amount of deflection that occurs in the part of the gun arm 100 located above the center in the Z-axis direction and the amount of deflection that occurs in the part located below the center during solid-phase resistance spot bonding.

[0049] The method of fixing the end effector to the gun arm 100 is not particularly limited. In this embodiment, the front portion of the end effector is fixed to the front portion of the gun arm 100 via six bolts, and the rear portion of the end effector is fixed to the rear portion of the gun arm 100 via six bolts.

[0050] For example, a vertical articulated robot arm with 6 degrees of freedom can be used as the robot arm 200. This allows the gun arm 100 to move in a desired posture and direction by the robot arm 200. The degrees of freedom of the robot arm 200 are not specifically limited to 6 degrees of freedom and may be changed as appropriate to achieve the desired performance. The operation of the robot arm 200 is controlled, for example, by a control device (not shown).

[0051] As shown in Figure 2, when joining objects 301 and 302 to each other using the joining device 1A, first, objects 301 and 302 are clamped in the Z-axis direction by the first pressing shaft 11 and the second pressing shaft 21, thereby pressing them from both sides. This creates protrusions on each of the objects 301 and 302 that come into contact with each other. The pressing force on objects 301 and 302 by the first pressing shaft 11 and the second pressing shaft 21 is, for example, 30kN to 70kN.

[0052] Next, with a pressing force applied to the objects 301 and 302, the first electrode 12 and the second electrode 22 are brought into contact with the objects 301 and 302, thereby applying a voltage to the objects 301 and 302. This heats the objects 301 and 302, causing softened regions to form on each of the protrusions, and the protrusions to join together in the softened regions. The current supplied to the objects 301 and 302 is, for example, 3.5kA to 10kA.

[0053] Figure 4 is a schematic front view illustrating the detailed configuration of the gun arm shown in Figure 3. Hereinafter, with reference to Figure 4, the detailed configuration of the beam portion 130 of the gun arm 100 provided in the joining device 1A according to this embodiment will be described.

[0054] In Figure 4, the 10 beam sections are numbered 131 to 140 in clockwise order, starting from the beam section protruding from the tip of the first extension 112. For ease of understanding, the approximate areas where beam sections 131 to 140 are located are indicated by diagonal lines. The intersections of the extension directions of each beam section 131 to 140 with the base section 111 are shown as intersections c1 to c10. Furthermore, among the acute angles that each extension direction of beam sections 131 to 140 makes with the base section 111, the acute angle that the extension direction of beam section 136 makes with the base section 111 is shown as angle s6, and the acute angle that the extension direction of beam section 138 makes with the base section 111 is shown as angle s8 for illustrative purposes.

[0055] As shown in Figure 4, the gun arm 100 includes an inner frame portion 110, an outer frame portion 120, and beam portions 131-140. By connecting the inner frame portion 110 and the outer frame portion 120 with the beam portions 131-140 to construct the gun arm 100, it is possible to reduce the weight compared to, for example, a plate-shaped gun arm with a uniform thickness throughout.

[0056] Viewed from the Y-axis direction, each of the beam sections 134 to 137 becomes thicker as it moves from the inner frame section 110 side towards the outer frame section 120 side. This improves the rigidity of the portion of the gun arm 100 that is on the outer frame section 120 side.

[0057] Viewed from the Y-axis direction, each of the beam sections 131 to 140 extends away from the central part C of the base section 111 in the Z-axis direction as it moves from the inner frame section 110 side toward the outer frame section 120 side.

[0058] Here, viewed from the Y-axis direction, the angle of the acute angle between the beam sections 131 to 140 and the base section 111 of the inner frame section 110 (more specifically, the edge of the base section 111) decreases as the intersection of the respective extension direction moves away from the central part C of the base section 111 in the Z-axis direction.

[0059] In detail, intersections c1 to c10 are arranged in the order of intersection c8, intersection c10, intersection c3, intersection c9, intersection c4, intersection c7, intersection c2, intersection c5, intersection c1, and intersection c6, starting from the one furthest from the central part C of the base part 111 in the Z-axis direction. Therefore, in this embodiment, among the acute angles corresponding to the respective extending directions of the beam parts 131 to 140, angle s6 is the largest and angle s8 is the smallest.

[0060] By configuring it in this way, a gun arm 100 can be made that is lightweight while improving rigidity. In the following sections, this point will be explained with reference to the results of simulation analysis using the finite element method (FEM).

[0061] Figure 5 is a perspective view of the simulation model of Example 1. Figure 6 is a six-view drawing of the gun arm of Example 1. Figure 7 is a perspective view of the gun arm of Example 1. Figure 8 is a six-view drawing of the gun arm of Comparative Example 1. Figure 9 is a perspective view of the gun arm of Comparative Example 1. Figure 10 is a front view showing the displacement distribution in the Z-axis direction of the gun arms of Example 1 and Comparative Example 1. Specifically, Figure 10(A) is a front view showing the displacement distribution of the gun arm of Example 1, and Figure 10(B) is a front view showing the displacement distribution of the gun arm of Comparative Example 1. Figure 11 is a table showing the absolute values ​​of the displacement amounts at the positions shown in Figure 10 for the gun arms of Example 1 and Comparative Example 1. Figure 12 is a front view showing the stress distribution of the gun arms of Example 1 and Comparative Example 1. Specifically, Figure 12(A) is a front view showing the stress distribution of the gun arm of Example 1, and Figure 12(B) is a front view showing the stress distribution of the gun arm of Comparative Example 1. In Figure 10, it is shown that the amount of displacement increases as the color changes from white to black. Figure 12 shows that the stress increases as the color changes from white to black.

[0062] As shown in Figures 5 to 7, Embodiment 1 is a simulation model that roughly corresponds to the gun arm 100, first joining unit 10, and second joining unit 20 of the joining device 1A according to the above-described embodiment. In detail, the gun arm 100 of Embodiment 1 differs from the gun arm 100 in Embodiment 1 in that the arrangement of the multiple beam sections 130 is generally the same, but the external shape of the gun arm 100 is simplified.

[0063] As shown in Figures 8 and 9, Comparative Example 1 differs from Example 1 only in the configuration of the gun arm. Specifically, the multiple beam sections 130 of the gun arm 100 in Comparative Example 1 connect the inner frame section 110 and the outer frame section 120 to each other, like a so-called Warren truss. The weight of the gun arm 100 in Example 1 and the gun arm 100 in Comparative Example 1 are the same.

[0064] For the simulation analysis conditions, the length dimension of the gun arm 100 in the X-axis direction was set to 580 mm, the length dimension in the Y-axis direction to 150 mm, and the length dimension in the Z-axis direction to 1080 mm. The material of the gun arm 100 was set to A2017, and the number of elements was set to approximately 800,000. In addition, a surface load of 70 kN directed outward in the Z-axis direction was set on both the region on the inner surface of the gun arm 100 where the second joint unit 20 is located and the region on the outer surface of the gun arm 100 where the first joint unit 10 is located (see region AR and load F in Figure 5). Furthermore, as a constraint condition, all 6 degrees of freedom at the 6 locations located in the center of the Z-axis direction of the gun arm 100 (see symbol R in Figure 5) were set to "fixed".

[0065] As a result of the simulation analysis, as shown in Figure 10, it was found that the displacement in Example 1 was generally smaller than the displacement in the Comparative Example. Furthermore, as shown in Figure 11, it was found that the displacement at position P1 of the first joining unit 10 and position P2 of the second joining unit 20 in Example 1 was smaller than the displacement at position P3 of the first joining unit 10 and position P4 of the second joining unit 20 in Comparative Example 1.

[0066] Thus, it has been found that by configuring the gun arm 100 in this embodiment, it is possible to create a gun arm that is less prone to bending and has increased rigidity.

[0067] Here, as shown in Figure 12, in both Example 1 and Comparative Example 1, high stress is distributed in the inner frame portion 110, and the stress generally decreases as you move from the inner frame portion 110 towards the outer frame portion 120.

[0068] Focusing on the stress distribution in the beam section 130, in Example 1, the stress is evenly distributed among adjacent beam sections 130 (see beam sections 133, 134, etc. in Example 1 in particular). This is thought to be because, by configuring as in Example 1, multiple beam sections 130 extend roughly radially from the vicinity of the central part C of the base section 111 of the inner frame section 110, and as a result, the transmission of load from the inner frame section 110 to the outer frame section 120 becomes easier.

[0069] On the other hand, in Comparative Example 1, high stress is unevenly distributed in one of the adjacent beam sections 130 (see beam sections 133, 134, etc., in particular in Comparative Example 1). This is thought to be because, in Comparative Example 1, both the portions where the inner frame section 110-side ends of multiple beam sections 130 are densely arranged, and the portions where the outer frame section 120-side ends of multiple beam sections 130 are densely arranged, are provided on the gun arm 100, resulting in a complex load transmission path from the inner frame section 110 to the outer frame section 120. As described above, the uneven distribution of high stress in some beam sections 130 leads to a large displacement in those beam sections 130, and as a result, the overall deflection of the gun arm in Comparative Example 1 is considered to be large.

[0070] As described above, it has been found that by configuring the gun arm 100 as in Example 1, it is possible to create a gun arm that is less prone to bending and has increased rigidity.

[0071] Therefore, by configuring the gun arm 100 and the joining device 1A equipped therewith according to this embodiment, it is possible to create a gun arm and a joining device equipped therewith that are lightweight while also improving rigidity.

[0072] In this embodiment, the example given is that the portion of the gun arm 100 enclosed by two adjacent beam portions 130 out of a plurality of beam portions 130, the inner frame portion 110, and the outer frame portion 120 is a hole 150 that penetrates in the Y-axis direction. However, instead of forming this portion with a hole 150, a reinforcing rib having a thickness smaller than the thickness of the other parts of the gun arm 100 may be provided in this portion. In this case as well, it is possible to reduce the weight of the gun arm 100.

[0073] Furthermore, in this embodiment, an example was given in which each of the first bonding unit 10 and the second bonding unit 20 has a pressurizing shaft and electrodes arranged around the pressurizing shaft so as to be spaced apart from the pressurizing shaft. However, the electrodes do not necessarily have to be spaced apart from the pressurizing shaft, and the circumferential surface of the pressurizing shaft may be in contact with the inner circumferential surface of the electrodes.

[0074] (Embodiment 2 and Embodiment 3) Figure 13 is a six-view drawing of the gun arm of Embodiment 2. Figure 14 is a perspective view of the gun arm of Embodiment 2. Figure 15 is a six-view drawing of the gun arm of Embodiment 3. Figure 16 is a perspective view of the gun arm of Embodiment 3. Next, with reference to Figures 13 to 16, the gun arm provided by the joining device 1B according to Embodiment 2 and the gun arm provided by the joining device 1C according to Embodiment 3 will be described. The gun arm of Embodiment 2 has beams arranged in a manner that roughly corresponds to the arrangement of beams of the gun arm according to Embodiment 2. The gun arm of Embodiment 3 has beams arranged in a manner that roughly corresponds to the arrangement of beams of the gun arm according to Embodiment 3.

[0075] As shown in Figures 13 and 14, the gun arm of Embodiment 2 has a smaller overall length along the Z-axis (see dimension Z2 in Figure 13(A)) compared to the gun arm of Embodiment 1 described above. Here, dimension Z1 is, for example, between 880 mm and 1080 mm. Dimension Z2 is, for example, between 680 mm and 880 mm.

[0076] As shown in Figures 15 and 16, the gun arm of Embodiment 3, compared to the gun arm of Embodiment 1, has a smaller overall length of the gun arm along the X-axis (see dimension X3 in Figure 15(A)) than the same length in Embodiment 1 (see dimension X1 in Figure 6(A)). Also, the distance between the tip of the first extension along the X-axis and the base (see dimension X4 in Figure 15(A)) is smaller than the same distance in Embodiment 1 (see dimension X2 in Figure 6(A)). Here, dimension X1 is, for example, 500 mm or more and 600 mm or less. Dimension X2 is, for example, 250 mm or more and 350 mm or less. Dimension X3 is, for example, 400 mm or more and 500 mm or less. Dimension X4 is, for example, 150 mm or more and 250 mm or less.

[0077] Even when the joining device 1B, 1C according to Embodiments 2, 3 is configured to have beams arranged in a manner roughly corresponding to the arrangement of beams in the gun arms of Embodiments 2, 3, the same effects as those described in Embodiment 1 above can be obtained, resulting in a gun arm and a joining device equipped therewith that are lightweight while improving rigidity.

[0078] (Embodiment 4) Figure 17 is a schematic diagram illustrating the joining device according to Embodiment 4. Next, the joining device 1D according to Embodiment 4 will be described with reference to Figure 17.

[0079] As shown in Figure 17, the joining device 1D according to Embodiment 4 differs from the joining device 1A according to Embodiment 1 described above in that the position of the part of the gun arm 100 to which the end effector of the robot arm 200 is connected is different.

[0080] In detail, in the joining device 1D, the end effector is connected to the first extension portion 112 of the inner frame portion 110, the outer frame portion 120 opposite to the first extension portion 112, and the beam portion 130 that connects these to each other.

[0081] Even with this configuration, the same effects as those described in Embodiment 1 above can be obtained, resulting in a gun arm and a connecting device equipped with it that are lightweight while also having improved rigidity.

[0082] (Note) The characteristic configuration of the gun arm and the joining device equipped therewith disclosed in the above-described embodiment can be summarized as follows.

[0083] [Note 1] A gun arm comprising a first joining unit and a second joining unit, which are capable of clamping and pressing multiple overlapping objects to be joined, and which can be mounted facing each other in a first direction, The inner frame portion that constitutes the inner circumference, The outer frame portion that constitutes the outer periphery, The system comprises the above-mentioned inner frame section and a plurality of beam sections that connect the above-mentioned outer frame section to each other. The inner frame portion has a base portion extending along the first direction, a first extension portion extending from one end of the base portion in the first direction along a second direction intersecting the first direction, and a second extension portion extending from the other end of the base portion in the first direction along the second direction and positioned opposite the first extension portion at a distance from it in the first direction. Viewed from the first direction and a third direction perpendicular to the second direction, each of the plurality of beam sections extends away from the central part of the base in the first direction as it moves from the inner frame section towards the outer frame section, A gun arm in which, when viewed from the third direction described above, the extension direction of each of the multiple beam sections is such that the acute angle formed between the base section and the intersection of the extension direction and the base section decreases as the intersection moves away from the central section in the first direction.

[0084] [Note 2] The gun arm as described in Appendix 1, wherein the portion enclosed by two adjacent beam sections among the multiple beam sections described above, the inner frame section, and the outer frame section is a hole that penetrates in the third direction.

[0085] [Note 3] The gun arm as described in Appendix 1 or 2, wherein, when viewed from the third direction described above, the multiple beam sections become thicker as they move from the inner frame section side toward the outer frame section side.

[0086] [Note 4] A gun arm as described in any one of the appendices 1 to 3, to which a robotic arm is connected at the center of the first direction described above.

[0087] [Note 5] A gun arm described in any one of the notes 1 to 4, A joining device comprising the above-described first joining unit and the above-described second joining unit.

[0088] [Note 6] A bonding apparatus as described in Appendix 5, used for solid-phase resistance spot bonding.

[0089] [Note 7] The first joining unit has a first pressing shaft that presses the plurality of objects to be joined in a way that allows for plastic deformation, and a first electrode that is arranged around the first pressing shaft and applies a voltage to the plurality of objects to be joined. The joining apparatus according to Appendix 5 or 6, wherein the second joining unit has a second pressing shaft for pressing the plurality of objects to be joined in a plastically deformable manner, and a second electrode arranged around the second pressing shaft for applying a voltage to the plurality of objects to be joined.

[0090] (Other forms, etc.) In the embodiments described above, the present invention was explained using as an example the application of a gun arm used in solid-phase resistance spot welding and a joining device equipped therewith. However, the present invention is naturally also applicable to gun arms used in friction stir welding, clinching, self-piercing rivets, resistance spot welding, projection welding, seam welding, and the like, as well as to joining devices equipped therewith.

[0091] Furthermore, the shape, configuration, size, number, material, etc., of each part shown in the above-described embodiment can be modified in various ways, as long as they do not depart from the spirit of the present invention.

[0092] Furthermore, the characteristic configurations shown in the embodiments described above can naturally be combined with each other without departing from the spirit of the present invention.

[0093] Thus, the embodiments disclosed herein are illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the claims and includes all modifications within the meaning and scope of equivalents to the claims. [Explanation of symbols]

[0094] 1A~1D Joining device, 10 First joining unit, 11 First pressure shaft, 12 First electrode, 20 Second joining unit, 21 Second pressure shaft, 22 Second electrode, 100 Gun arm, 110 Inner frame section, 111 Base section, 111a One end, 111b Other end, 112 First extension section, 113 Second extension section, 120 Outer frame section, 130, 131~140 Beam section, 150 Hole section, 200 Robot arm, 301, 302 Workpieces to be joined, C Central section.

Claims

1. A gun arm comprising a first joining unit and a second joining unit, which are capable of clamping and pressing multiple overlapping objects to be joined, and which can be mounted facing each other in a first direction, The inner frame portion that constitutes the inner circumference, The outer frame portion that constitutes the outer periphery, The system comprises the inner frame portion and the outer frame portion, and a plurality of beam portions that connect them to each other. The inner frame portion includes a base portion extending along the first direction, a first extension portion extending from one end of the base portion in the first direction along a second direction intersecting the first direction, and a second extension portion extending from the other end of the base portion in the first direction along the second direction and positioned opposite the first extension portion at a distance from it in the first direction. Viewed from a third direction perpendicular to the first and second directions, each of the plurality of beam sections extends away from the central part of the base section in the first direction as it moves from the inner frame section side toward the outer frame section side, A gun arm in which, when viewed from the third direction, the extending direction of each of the plurality of beams is such that the acute angle it makes with the base portion decreases as the intersection of the extending direction and the base portion moves away from the central portion in the first direction.

2. The gun arm according to claim 1, wherein the portion enclosed by two adjacent beams among the plurality of beams, the inner frame portion and the outer frame portion is a hole that penetrates in the third direction.

3. The gun arm according to claim 1, wherein, when viewed from the third direction, the plurality of beam portions become thicker from the inner frame portion side toward the outer frame portion side.

4. The gun arm according to claim 1, wherein a robotic arm is connected to the center in the first direction.

5. A gun arm according to any one of claims 1 to 4, A joining device comprising the first joining unit and the second joining unit.

6. The bonding apparatus according to claim 5, which is used for solid-phase resistance spot bonding.

7. The first joining unit includes a first pressing shaft that presses the plurality of objects to be joined in a way that allows for plastic deformation, and a first electrode arranged around the first pressing shaft that applies a voltage to the plurality of objects to be joined. The joining apparatus according to claim 6, wherein the second joining unit includes a second pressurizing shaft for pressing the plurality of objects to be joined in a plastically deformable manner, and a second electrode arranged around the second pressurizing shaft for applying a voltage to the plurality of objects to be joined.

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