Gun arm and joining device

Abstract

The invention provides a gun arm and a joining device which are light in weight and improved in rigidity. The gun arm includes an inner frame portion, an outer frame portion, and a beam portion. The inner frame portion includes a base portion, and a first extension portion and a second extension portion extending in a second direction from one end portion and the other end portion of the base portion in the first direction, respectively. When viewed from a third direction orthogonal to the first and second directions, each of the beam portions extends so as to be separated in the first direction from a central portion of the base portion in the first direction as the beam portions tend from the inner frame portion side toward the outer frame portion side. When viewed from the third direction, with respect to the extension direction of each of the beam portions, the acute angle formed by the beam portion and the base portion becomes smaller as the intersection point of the extension direction and the base portion moves away from the center portion in the first direction.

Description

TECHNICAL FIELD

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

[0002] Conventionally, various methods of joining a plurality of joined objects are known. For example, a joining device for performing friction stir joining is disclosed in Japanese Patent Application Publication No. 2014-168805 as an example of the above-described method. In addition, a joining device for performing solid phase resistance spot joining is disclosed in International Publication No. 2021 / 182444 as another example of the above-described method. Both of these joining devices are provided with a pair of joining units that are arranged in opposition on the same axis and press a plurality of joined objects in a clampable manner.

[0003] From the viewpoint of achieving an improvement in work efficiency in these joining methods, it is considered to apply a robot arm to the joining device, for example, as disclosed in the above-described patent document 1. In this case, the robot arm is linked to a gun arm on which the above-described pair of joining units are mounted. SUMMARY

[0004] Here, in order to ensure the joining quality in the above-described various joining methods, it is important that the above-described pair of joining units are arranged on the same axis without causing axis misalignment.

[0005] In this regard, in the case where a load is applied to a joined object by pressing the joined object with the above-described pair of joining units, a reaction force of the load is applied to the gun arm. When deflection occurs in the gun arm as a result of this, it is possible that axis misalignment occurs in the above-described pair of joining units, and as a result, a decrease in joining quality is incurred.

[0006] This problem becomes a particularly significant problem in the case where solid phase resistance spot joining, which tends to apply a larger load to a joined object than other joining methods, is performed, in the case where the gun arm is constituted by a frame or the thickness of the gun arm is reduced in order to achieve lightening of the joining device, and the like.

[0007] Therefore, the present application was completed in order to solve the above-described problems, and aims to provide a gun arm that achieves lightening while also achieving an improvement in rigidity, and a joining device provided with the gun arm.

[0008] The gun arm based on the present invention can mount a first joining unit and a second joining unit of multiple overlapping objects that can be clamped and pressed together in a manner facing each other in a first direction. The gun arm based on the present invention includes: an inner frame portion forming the inner periphery of the gun arm; an outer frame portion forming the outer periphery of the gun arm; and a plurality of beam portions connecting the inner frame portion and the outer frame portion. The inner frame portion has a base, 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 along the first direction along a second direction intersecting the first direction. The second extension portion extends from the other end of the base portion along the second direction and is spaced apart from the first extension portion in the first direction. When viewed from a third direction orthogonal to the first and second directions, each of the plurality of beam portions extends away from the center portion of the base portion along the first direction as it moves from the inner frame portion side towards the outer frame portion side. When viewed from the aforementioned third direction, for each of the aforementioned multiple beams in its respective extension direction, as the point of intersection of the extension direction and the base moves away from the central portion along the aforementioned first direction, the acute angle formed by the extension direction and the base decreases.

[0009] This design allows for a gun arm that achieves both lightweight construction and increased rigidity.

[0010] In the gun arm based on the present invention described above, the portion surrounded by two adjacent beams of the plurality of beams, the inner frame portion, and the outer frame portion may be a through hole extending in the third direction.

[0011] This design allows for further weight reduction of the gun arm.

[0012] In the gun arm based on the present invention described above, when viewed from the third direction, the plurality of beams may thicken as they move from the inner frame side to the outer frame side.

[0013] This configuration increases the rigidity of the outer frame portion of the gun arm.

[0014] In the gun arm based on the present invention, it is also possible that a mechanical arm is connected to the center of the gun arm in the first direction.

[0015] By configuring it in this way, it is possible to reduce the difference between the amount of deflection generated in the portion of the gun arm located above the center in the first direction and the amount of deflection generated in the portion located below the center in the first direction when multiple objects are joined.

[0016] The joining device based on the present invention includes: a gun arm based on the present invention described above; and the first joining unit and the second joining unit described above.

[0017] This configuration allows for the creation of a gun arm assembly that achieves both lightweighting and increased rigidity.

[0018] The bonding device based on the present invention can also be used for solid-state resistance point bonding. With this configuration, solid-state resistance point bonding can be performed.

[0019] In the bonding apparatus based on the present invention described above, the first bonding unit may also include: a first pressure shaft that presses the plurality of objects to be bonded in a manner capable of plastic deformation; and a first electrode disposed around the first pressure shaft and applying a voltage to the plurality of objects to be bonded. Alternatively, the second bonding unit may include: a second pressure shaft that presses the plurality of objects to be bonded in a manner capable of plastic deformation; and a second electrode disposed around the second pressure shaft and applying a voltage to the plurality of objects to be bonded. With this configuration, solid-state resistive point bonding can be performed.

[0020] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description relating to the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the coupling device of Embodiment 1.

[0022] Figure 2 It is a schematic cross-sectional view that schematically shows the situation near the bonded object when solid-state resistive point bonding is performed.

[0023] Figures 3A-3F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm with the first and second engagement units installed.

[0024] Figure 4 It is used for explanation Figures 3A-3F The diagram shows a front view illustrating the detailed structure of the gun arm.

[0025] Figure 5 This is a three-dimensional view of the simulation model of Example 1.

[0026] Figures 6A-6F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Embodiment 1.

[0027] Figure 7 This is a perspective view of the gun arm in Example 1.

[0028] Figures 8A-8F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Comparative Example 1.

[0029] Figure 9 This is a three-dimensional view of the gun arm of Comparative Example 1.

[0030] Figure 10A as well as Figure 10B These are front views showing the displacement distribution in the Z-axis direction of the gun arm in Example 1 and Comparative Example 1, respectively.

[0031] Figure 11 This is a table showing the displacement in the Z-axis direction at a specified position of the gun arm in Example 1 and Comparative Example 1.

[0032] Figure 12A as well as Figure 12B These are front views showing the stress distribution in the gun arm of Example 1 and Comparative Example 1, respectively.

[0033] Figures 13A-13F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Embodiment 2.

[0034] Figure 14 This is a perspective view of the gun arm in Example 2.

[0035] Figures 15A-15F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Embodiment 3.

[0036] Figure 16 This is a perspective view of the gun arm in Example 3.

[0037] Figure 17 This is a schematic diagram showing the coupling device of Embodiment 4. Detailed Implementation

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the figures. It should be noted that in the embodiments shown below, the same or common parts are labeled with the same reference numerals in the figures, and their descriptions will not be repeated. In the following embodiments of the present invention, a gun arm for solid-state resistive point bonding and a bonding device having the gun arm will be described as examples.

[0039] (Implementation Method 1)

[0040] Figure 1 This is a schematic diagram showing the coupling device of Embodiment 1. Figure 2 It is a schematic cross-sectional view that schematically shows the situation near the bonded object when solid-state resistive point bonding is performed. Figures 3A-3FThis is a six-view diagram of the gun arm with the first and second engagement units installed. More specifically, Figures 3A-3F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm (more details to follow). Figures 6A-6F , Figures 8A-8F , Figures 13A-13F as well as Figures 15A-15F It's the same. Figure 4 It is used for explanation Figures 3A-3F The diagram shows a detailed front view of the gun arm's structure. The following refers to... Figures 1-4 The overall structure of the gun arm 100 and the coupling device 1A having the gun arm 100 in this embodiment will be described.

[0041] It should be noted that in the following explanation, such as Figure 1 As shown, the left-right direction when viewing the gun arm 100 from the front is also called the X-axis direction. Furthermore, the front-back direction when viewing the gun arm 100 from the front is also called the Y-axis direction. And the up-down direction when viewing the gun arm 100 from the front is also called the Z-axis direction.

[0042] The joining device 1A is a so-called solid-state resistance point joining device for joining multiple substrates together in a solid state at low temperature without melting. In detail, the joining device 1A forms softened regions on the overlapping substrates by applying a voltage to them, and plastically deforms the softened regions by applying a load to the substrates in the state of having the softened regions formed.

[0043] In this embodiment, the plate-shaped objects 301 and 302 are joined together by the joining device 1A. It should be noted that the number of objects being joined is not particularly limited to two, and may also be three or more.

[0044] The joined materials 301 and 302 are made of, for example, steel plates of high tensile strength. It should be noted that the joined materials 301 and 302 are not particularly limited to being made of steel plates; they may also be made of aluminum plates or the like. Furthermore, the joined materials 301 and 302 may also be made of dissimilar materials such as steel plates and aluminum plates.

[0045] like Figure 1 , Figure 2 as well as Figures 3A-3F As shown, the joining device 1A includes a first joining unit 10, a second joining unit 20, a gun arm 100, and a robotic arm 200. The first joining unit 10 and the second joining unit 20 press down on the overlapping objects to be joined in a clamping manner.

[0046] The first bonding unit 10 has a first pressure shaft 11 and a first electrode 12. The first bonding unit 10 is driven along the Z-axis by a drive device such as a servo press (not shown). Power is supplied to the first bonding unit 10 from a power source (not shown).

[0047] In this embodiment, the first direction corresponds to the Z-axis direction, and the second direction intersecting the first direction corresponds to the X-axis direction. A third direction orthogonal to both the first and second directions corresponds to the Y-axis direction.

[0048] The first pressure shaft 11 has a generally cylindrical portion. The first pressure shaft 11 plastically deforms the overlapping joints 301 and 302 by pressing them along the Z-axis.

[0049] The first electrode 12 has a generally cylindrical portion. The first electrode 12 is disposed around the first pressure shaft 11 in a radially separated manner from the first pressure shaft 11. The first electrode 12 applies a voltage to the substrates 301 and 302.

[0050] 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 source not shown.

[0051] The second pressure shaft 21 has a generally cylindrical portion. The second pressure shaft 21 plastically deforms the overlapping joints 301 and 302 by pressing them along the Z-axis.

[0052] The second electrode 22 has a generally cylindrical portion. The second electrode 22 is disposed around the second pressure shaft 21 in a radially separated manner from the second pressure shaft 21. The second electrode 22 applies a voltage to the substrates 301 and 302.

[0053] The first pressure shaft 11 and the second pressure shaft 21 are made of, for example, tungsten carbide. It should be noted that the material of the first pressure shaft 11 and the second pressure shaft 21 is not particularly limited to tungsten carbide, as long as it can press the joined materials 301 and 302 in a manner capable of plastic deformation; it can also be tool steel, heat-resistant steel, or ceramic, etc. The first electrode 12 and the second electrode 22 are made of, for example, copper.

[0054] The first engagement unit 10 and the second engagement unit 20 are coaxially arranged and opposite each other in the Z-axis direction by being mounted on the gun arm 100.

[0055] like Figure 1 as well as Figures 3A-3FAs shown, 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 generally C-shaped shape when viewed from the Y-axis direction. The inner frame portion 110 constitutes the inner periphery of the gun arm 100. The outer frame portion 120 constitutes the outer periphery of the gun arm 100.

[0056] The inner frame portion 110 has a base 111, a first extension 112, and a second extension 113. The base 111 extends along the Z-axis direction. The first extension 112 extends from one end 111a of the base 111 along the Z-axis direction along the X-axis direction. The second extension 113 extends from the other end 111b of the base 111 along the Z-axis direction along the X-axis direction. The first extension 112 and the second extension 113 are arranged opposite each other at a distance from each other in the Z-axis direction. It should be noted that the extending direction of the first extension 112 and the second extension 113 does not necessarily have to be consistent with the X-axis direction, and may also extend along a direction that is correspondingly inclined from the X-axis direction.

[0057] The first engagement unit 10 is disposed protruding from the first extension 112 with its front end facing the second extension 113. The second engagement unit 20 is disposed protruding from the second extension 113 with its front end facing the first extension 112.

[0058] Therefore, a joining space 500 is provided between the first extension 112 and the second extension 113, which serves as a space for joining the joined objects 301 and 302 together using the first joining unit 10 and the second joining unit 20.

[0059] The first engagement unit 10 is driven along the Z-axis direction by the driving device as described above. Thus, the first engagement unit 10 is configured to be able to move relative to the second engagement unit 20 along the Z-axis direction.

[0060] When viewed from the inner frame portion 110, the outer frame portion 120 is positioned at a distance from the inner frame portion 110 on the side opposite to the engagement space 500.

[0061] Multiple beams 130 are arranged to connect to each other in a manner that bridges the inner frame portion 110 and the outer frame portion 120. In this embodiment, the gun arm 100 includes 10 beams 130. It should be noted that the beams 130 will be described in detail later.

[0062] At least a portion of the portion of the gun arm 100 surrounded by two adjacent beams 130, an inner frame portion 110, and an outer frame portion 120 is a through hole 150 extending along the Y-axis. By providing multiple holes 150 throughout the gun arm 100, the gun arm 100 can be made lighter. In this embodiment, the gun arm 100 includes 11 holes 150.

[0063] The gun arm 100 is, for example, composed of a formed part 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 component that serves as the raw material.

[0064] A robotic arm 200 is connected to the gun arm 100. In this embodiment, the end effector of the robotic arm 200 is connected to the center of the gun arm 100 in the Z-axis direction. As a result, the difference between the deflection amount generated in the portion of the gun arm 100 located above the center in the Z-axis direction and the deflection amount generated in the portion located below the center in the Z-axis direction during solid-state resistive point engagement can be reduced.

[0065] There are no particular limitations on the method of fixing the end effector relative to the gun arm 100. In this embodiment, the front side of the end effector is fixed to the front side of the gun arm 100 by means of 6 bolts, and the rear side of the end effector is fixed to the rear side of the gun arm 100 by means of 6 bolts.

[0066] As the robotic arm 200, for example, a vertical multi-joint robotic arm with 6 degrees of freedom is used. Thus, the gun arm 100 is configured to move in a desired orientation and direction under the action of the robotic arm 200. It should be noted that the degrees of freedom of the robotic arm 200 are not specifically limited to 6 degrees of freedom and can be appropriately modified to achieve the desired performance. The movements of the robotic arm 200 are controlled, for example, by a control device (not shown).

[0067] like Figure 2 As shown, when using the joining device 1A to join the objects 301 and 302 together, firstly, the objects 301 and 302 are clamped along the Z-axis direction using the first pressure shaft 11 and the second pressure shaft 21, thereby pressing the objects 301 and 302 from both sides. This creates protrusions that contact each other on each of the objects 301 and 302. The pressing force applied to the objects 301 and 302 by the first pressure shaft 11 and the second pressure shaft 21 is, for example, set to 30kN to 70kN.

[0068] Next, by bringing the first electrode 12 and the second electrode 22 into contact with the workpieces 301 and 302 while applying pressure, a voltage is applied to the workpieces 301 and 302. This heats the workpieces 301 and 302, forming softened regions on each of the protrusions, and the protrusions then bond to each other within these softened regions. The current flowing through the workpieces 301 and 302 is, for example, set to 3.5 kA to 10 kA.

[0069] Figure 4 It is used for explanation Figures 3A-3F The diagram shows a detailed front view of the gun arm's structure. The following refers to... Figure 4 The detailed structure of the beam portion 130 of the gun arm 100 provided in the coupling device 1A of this embodiment will be described.

[0070] It should be noted that, in Figure 4 In this diagram, ten beam sections are numbered 131 to 140 clockwise, starting from the beam section protruding from the front end of the first extension 112. For ease of understanding, the approximate areas of beam sections 131 to 140 are indicated using diagonal lines. Furthermore, the intersection points of the extension directions of each beam section 131 to 140 with the base 111 are shown as intersection points c1 to c10. Additionally, the acute angle formed by the extension directions of each beam section 131 to 140 with the base 111 is exemplified as angle s6 for beam section 136 and angle s8 for beam section 138.

[0071] like Figure 4 As shown, the gun arm 100 includes an inner frame portion 110, an outer frame portion 120, and beam portions 131-140. The gun arm 100 is formed by connecting the inner frame portion 110 and the outer frame portion 120 together using the beam portions 131-140, thereby achieving a lighter weight, for example, compared to a plate-shaped gun arm with a uniform thickness throughout.

[0072] When viewed from the Y-axis direction, beams 134-137 each thicken as they move from the inner frame portion 110 towards the outer frame portion 120. This increases the rigidity of the portion of the gun arm 100 on the outer frame portion 120 side.

[0073] When viewed from the Y-axis direction, each of the beams 131 to 140 extends away from the center portion C of the base 111 in the Z-axis direction as it moves from the inner frame portion 110 side toward the outer frame portion 120 side.

[0074] Here, when viewed from the Y-axis direction, for the respective extension directions of beams 131 to 140, as the intersection of the extension direction with the base 111 (more specifically, the edge of the base 111) of the inner frame 110 moves away from the center C of the base 111 along the Z-axis direction, the angle of the acute angle formed by the extension direction and the base 111 decreases.

[0075] In detail, the intersection points c1 to c10 are arranged in the order of intersection point c8, intersection point c10, intersection point c3, intersection point c9, intersection point c4, intersection point c7, intersection point c2, intersection point c5, intersection point c1, and intersection point c6, starting from the point furthest away from the central portion C of the base 111 along the Z-axis. Therefore, in this embodiment, among the acute angles corresponding to the respective extending directions of the beam portions 131 to 140, angle s6 is the largest and angle s8 is the smallest.

[0076] This configuration allows for both lightweight design and increased rigidity in the gun arm 100. This point will be explained below with reference to simulation results using the finite element method (FEM).

[0077] Figure 5 This is a three-dimensional view of the simulation model of Example 1. Figures 6A-6F This is a six-view drawing of the gun arm in Embodiment 1. In detail, Figures 6A-6F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Embodiment 1. Figure 7 This is a perspective view of the gun arm in Example 1. Figures 8A-8F This is a six-view diagram of the gun arm in Comparative Example 1. In detail, Figures 8A-8F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Comparative Example 1. Figure 9 This is a three-dimensional view of the gun arm of Comparative Example 1. Figure 10A This is a front view showing the displacement distribution in the gun arm of Embodiment 1. Figure 10B This is a front view showing the displacement distribution in the gun arm of Comparative Example 1. Figure 11 This illustrates the gun arm of Embodiment 1 and Comparative Example 1. Figure 10A as well as Figure 10B A table of absolute values ​​of displacement at the specified positions. Figure 12A This is a front view showing the stress distribution in the gun arm of Embodiment 1. Figure 12B This is a front view showing the stress distribution in the gun arm of Comparative Example 1. Figure 10A as well as Figure 10B In the diagram, the change from white to black indicates a larger displacement. Figure 12A as well as Figure 12B In the diagram, the change from white to black indicates increased stress.

[0078] likeFigures 5-7 As shown, Embodiment 1 is a simulation model that roughly corresponds to the gun arm 100, the first joining unit 10, and the second joining unit 20 of the joining device 1A of the above-described embodiment. In detail, the gun arm 100 of Embodiment 1 is roughly the same as the gun arm 100 in Embodiment 1 in terms of the arrangement of the plurality of beams 130, but differs in the simplification of the external shape of the gun arm 100.

[0079] like Figures 8A-8F as well as Figure 9 As shown, Comparative Example 1 differs from Example 1 only in the structure of the gun arm. Specifically, in Comparative Example 1, the multiple beams 130 of the gun arm 100 connect the inner frame portion 110 to the outer frame portion 120 in a manner similar to a so-called Warren truss. It should be noted that the weight of the gun arm 100 in Example 1 is the same as that of the gun arm 100 in Comparative Example 1.

[0080] As simulation analysis conditions, the length of the gun arm 100 in the X-axis direction is set to 580mm, the length in the Y-axis direction is set to 150mm, and the length in the Z-axis direction is set to 1080mm. The material of the gun arm 100 is set to A2017, and the number of elements is set to approximately 800,000. Additionally, a surface load of 70kN is set towards the outer side of the Z-axis in both the area containing the second joint unit 20 on the inner circumferential surface of the gun arm 100 and the area containing the first joint unit 10 on the outer circumferential surface of the gun arm 100 (refer to...). Figure 5 The region AR and load F in the middle). Furthermore, as constraints, six locations at the center of the gun arm 100 in the Z-axis direction (refer to...) Figure 5 All 6 degrees of freedom of the label R in the figure are set to "fixed".

[0081] The results of the simulation analysis show that, as Figure 10A as well as Figure 10B As shown, the displacement in Example 1 is generally smaller compared to the displacement in the comparative example. Furthermore, as... Figure 11 As shown, it can be seen that the displacement of the first joining unit 10 at position P1 and the second joining unit 20 at position P2 in Embodiment 1 is smaller than that of the first joining unit 10 at position P3 and the second joining unit 20 at position P4 in Comparative Example 1.

[0082] Thus, it can be seen that by constructing it as in the embodiment of the gun arm 100, flexing is difficult to occur, and a gun arm with increased rigidity can be obtained.

[0083] Here, as Figure 12A as well as Figure 12BAs shown, in either Example 1 or Comparative Example 1, a higher stress is distributed in the inner frame portion 110, and the stress generally decreases as it moves from the inner frame portion 110 to the outer frame portion 120.

[0084] Considering the stress distribution within the beam portion 130, in Embodiment 1, the stress is well distributed evenly among adjacent beam portions 130 (especially beam portions 133, 134, etc., in Embodiment 1). This is believed to be because, by constructing as in Embodiment 1, the plurality of beam portions 130 extend generally radially from near the central portion C of the base 111 of the inner frame portion 110, resulting in easier transfer of loads from the inner frame portion 110 toward the outer frame portion 120.

[0085] On the other hand, in Comparative Example 1, higher stress is displaced in one of the adjacent beam portions 130 (especially referencing beam portions 133, 134, etc. in Comparative Example 1). This is believed to be because, in Comparative Example 1, both the inner frame portion 110 side and the outer frame portion 120 side of each of the multiple beam portions 130 are densely arranged, thus the load transmission path from the inner frame portion 110 to the outer frame portion 120 is complex. As described above, since the beam portion 130 displaced to a certain extent generates higher stress, the displacement in that beam portion 130 increases, resulting in greater deflection of the gun arm as a whole in Comparative Example 1.

[0086] As described above, it can be seen that by constructing the gun arm 100 as in Embodiment 1, flexing is difficult to occur, and a gun arm with increased rigidity can be achieved.

[0087] Therefore, by constructing the gun arm 100 and the connecting device 1A having the gun arm 100 as in this embodiment, it is possible to achieve both lightweighting and increased rigidity in the gun arm and the connecting device having the gun arm.

[0088] It should be noted that, in this embodiment, the portion of the gun arm 100 surrounded by two adjacent beams 130 of the plurality of beams 130, the inner frame portion 110, and the outer frame portion 120 is an example of a hole 150 extending along the Y-axis. However, it is also possible to replace this portion with a hole 150, and instead provide a reinforcing rib with a thickness dimension smaller than that of other parts of the gun arm 100. In this case, the weight reduction of the gun arm 100 can also be achieved.

[0089] In addition, in this embodiment, the first bonding unit 10 and the second bonding unit 20 are each shown to have a pressure shaft and an electrode arranged around the pressure shaft in a manner that is separate from the pressure shaft. However, the electrode does not necessarily have to be arranged separately from the pressure shaft, and the peripheral surface of the pressure shaft may also abut against the inner peripheral surface of the electrode.

[0090] (Implementation Method 2 and Implementation Method 3)

[0091] Figures 13A-13F This is a six-view drawing of the gun arm in Embodiment 2. In detail, Figures 13A-13F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Embodiment 2. Figure 14 This is a perspective view of the gun arm in Example 2. Figures 15A-15F This is a six-view drawing of the gun arm in Embodiment 3. In detail, Figures 15A-15F These are the front view, rear view, left view, right view, top view, and bottom view of the gun arm in Embodiment 3. Figure 16 This is a perspective view of the gun arm in Embodiment 3. Next, refer to... Figures 13A-13F , Figure 14 , Figures 15A-15F as well as Figure 16 The gun arm included in the coupling device 1B of Embodiment 2 and the gun arm included in the coupling device 1C of Embodiment 3 will be described. It should be noted that the gun arm of Embodiment 2 has a beam portion with a configuration that approximately corresponds to the beam portion configuration of the gun arm of Embodiment 2. Furthermore, the gun arm of Embodiment 3 has a beam portion with a configuration that approximately corresponds to the beam portion configuration of the gun arm of Embodiment 3.

[0092] like Figures 13A-13F as well as Figure 14 As shown, when comparing the gun arm of Embodiment 2 with the gun arm of Embodiment 1 described above, the overall length of the gun arm along the Z-axis (refer to...) Figure 13A The dimension Z2 in the example is greater than the length in Example 1 (refer to the length in Example 1). Figure 6A The dimension Z1 is smaller. Here, dimension Z1 is set to be, for example, 880mm or more and 1080mm or less. Dimension Z2 is set to be, for example, 680mm or more and 880mm or less.

[0093] like Figures 15A-15F as well as Figure 16 As shown, when comparing the gun arm of Embodiment 3 with that of Embodiment 1, the overall length of the gun arm along the X-axis (refer to...) Figure 15A The dimension (X3) is greater than the length in Example 1 (refer to) Figure 6A The size (X1) is small. Additionally, the distance between the front end of the first extension and the base along the X-axis direction (refer to...) Figure 15A The dimension (X4) is greater than the distance in Example 1 (refer to)Figure 6A The smaller of the two dimensions is X2. Here, dimension X1 is, for example, 500mm or more and 600mm or less. Dimension X2 is, for example, 250mm or more and 350mm or less. Dimension X3 is, for example, 400mm or more and 500mm or less. Dimension X4 is, for example, 150mm or more and 250mm or less.

[0094] In the case where the connecting device 1B or 1C of Embodiment 2 or 3 has a beam configuration that roughly corresponds to the configuration of the beam portion of the gun arm in Embodiments 2 and 3, the same effect as described in Embodiment 1 above is obtained, and a gun arm and a connecting device having the gun arm can be achieved while achieving both lightweighting and increased rigidity.

[0095] (Implementation Method 4)

[0096] Figure 17 This is a schematic diagram illustrating the joining device of Embodiment 4. Next, refer to... Figure 17 The joining device 1D of Embodiment 4 will be described.

[0097] like Figure 17 As shown, in the case of the engagement device 1D of Embodiment 4 compared with the engagement device 1A of Embodiment 1 described above, the position of the part of the gun arm 100 that connects to the end effector of the robotic arm 200 is different.

[0098] In detail, in the engagement device 1D, the end effector is connected to the first extension 112 of the inner frame portion 110, the outer frame portion 120 opposite to the first extension 112, and the beam portion 130 that connects them to each other.

[0099] With this configuration, the same effect as described in Embodiment 1 above is obtained, which can achieve both lightweighting and increased rigidity of the gun arm and the connecting device having the gun arm.

[0100] (Postscript)

[0101] If we summarize the characteristic structure of the gun arm and the coupling device having the gun arm disclosed in the above embodiments, it is as follows.

[0102] [Appendix 1]

[0103] A gun arm capable of mounting a first engagement unit and a second engagement unit, which can clamp and press multiple overlapping objects together, in a manner opposing each other in a first direction, wherein...

[0104] The aforementioned gun arm has:

[0105] The inner frame portion constitutes the inner periphery of the aforementioned gun arm;

[0106] The outer frame portion, which constitutes the outer periphery of the aforementioned gun arm; and

[0107] Multiple beams connect the aforementioned inner frame portion and the aforementioned outer frame portion to each other.

[0108] The aforementioned inner frame portion has: a base extending along the first direction; a first extension extending from one end of the base along the first direction along a second direction intersecting the first direction; and a second extension extending from the other end of the base along the second direction, and disposed at a distance from the first extension in the first direction.

[0109] When viewed from a third direction orthogonal to the first and second directions, each of the plurality of beams extends away from the central portion of the base along the first direction as it moves from the inner frame portion side toward the outer frame portion side.

[0110] When viewed from the aforementioned third direction, for each of the aforementioned multiple beams in its respective extension direction, as the point of intersection of the extension direction and the base moves away from the central portion along the aforementioned first direction, the acute angle formed by the extension direction and the base decreases.

[0111] [Appendix 2]

[0112] According to the gun arm described in Appendix 1, wherein,

[0113] The portion surrounded by two adjacent beams among the aforementioned multiple beams, the aforementioned inner frame portion, and the aforementioned outer frame portion is a hole that extends through the aforementioned third direction.

[0114] [Appendix 3]

[0115] According to the gun arm described in Appendix 1 or 2, wherein,

[0116] When viewed from the aforementioned third-party perspective, the aforementioned multiple beams thicken as they move from the inner frame side to the outer frame side.

[0117] [Appendix 4]

[0118] The gun arm according to any one of Appendices 1 to 3, wherein,

[0119] The aforementioned gun arm is connected to a robotic arm at the center of the aforementioned first direction.

[0120] [Appendix 5]

[0121] A coupling device, wherein,

[0122] The aforementioned coupling device includes:

[0123] The gun arm as described in any one of Annexes 1 to 4; and

[0124] The first joining unit and the second joining unit mentioned above.

[0125] [Appendix 6]

[0126] According to the coupling device described in Appendix 5, wherein...

[0127] The aforementioned bonding device is used for solid-state resistance point bonding.

[0128] [Appendix 7]

[0129] According to the coupling device described in Appendix 5 or 6, wherein...

[0130] The first bonding unit comprises: a first pressure shaft that presses the plurality of bonded objects in a manner capable of plastic deformation; and a first electrode disposed around the first pressure shaft and applying a voltage to the plurality of bonded objects.

[0131] The second bonding unit comprises: a second pressure shaft that presses the plurality of bonded objects in a manner capable of plastic deformation; and a second electrode disposed around the second pressure shaft and applying a voltage to the plurality of bonded objects.

[0132] (Other methods, etc.)

[0133] In the above embodiments, the application of the present invention to a gun arm for solid-state resistance spot welding and a joining device having the gun arm has been described as an example. However, the present invention can also be applied to gun arms used in friction stir welding, clinching, self-piercing riveting, resistance spot welding, projection welding, seam welding, etc., and to joining devices having the gun arm.

[0134] Furthermore, the shape, structure, size, quantity, material, etc. of the various parts shown in the above embodiments can be modified in various ways as long as they do not depart from the spirit of the present invention.

[0135] Furthermore, the characteristic structures shown in the above embodiments can of course be combined with each other without departing from the spirit of the present invention.

[0136] Embodiments of the present invention have been described, but the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is shown by the technical solutions and is intended to include equivalents and all modifications within the scope of the technical solutions.

Claims

1. A gun arm capable of pressing first and second joining units of a plurality of joined objects that can be gripped in a sandwiched manner so as to face each other in a first direction, wherein the gun arm comprises: an inner frame portion that constitutes an inner peripheral portion of the gun arm; an outer frame portion that constitutes an outer peripheral portion of the gun arm; and a plurality of beam portions that connect the inner frame portion and the outer frame portion to each other, the inner frame portion has: a base portion that extends in the first direction; a first extension portion that extends from one end portion of the base portion in a second direction that intersects the first direction; and a second extension portion that extends from the other end portion of the base portion in the second direction so as to be disposed in opposition to the first extension portion at a spacing in the first direction, each of the plurality of beam portions extends in the first direction away from a central portion of the base portion in the first direction as it approaches from the inner frame portion side toward the outer frame portion side when viewed in a third direction that is orthogonal to the first and second directions, and the angle of an acute angle formed by the base portion becomes smaller as a point of intersection of the extension direction of each of the plurality of beam portions and the base portion moves away from the central portion in the first direction when viewed in the third direction.

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

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

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

5. A joining device, wherein the joining device comprises: the gun arm according to any one of claims 1 to 4; and the first and second joining units.

6. The joining device according to claim 5, wherein the joining device is used for solid resistance spot joining.

7. The joining device according to claim 6, wherein the first joining unit has: a first pressing shaft that presses the plurality of joined objects in a manner that allows plastic deformation; and a first electrode that is disposed around the first pressing shaft and applies a voltage to the plurality of joined objects, and the second joining unit has: a second pressing shaft that presses the plurality of joined objects in a manner that allows plastic deformation; and a second electrode that is disposed around the second pressing shaft and applies a voltage to the plurality of joined objects. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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