Frame joint structure

Abstract

To provide a frame joining structure capable of suppressing projection of a fastener from the frame, thereby reducing the size and saving space.SOLUTION: A pair of frames are tabular and have a through hole 31 formed on them. Fasteners 16 are fitted into both of the through holes 31 juxtaposed in an axis direction with the pair of frames overlapped with each other. In each through hole 31, an engagement claw 32 protruding inward in a radial direction is formed. On an outer peripheral surface 41 of the fastener 16, an engagement groove 43 which is engaged with each engagement claw 32 and gradually changes its axial position along the circumferential direction is formed. When the fasteners 16 are fitted into both through holes 31 and made to rotate, each engagement claw 32 is deformed along the engagement groove 43 so that the pair of frames are joined to each other by the fasteners 16.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a frame joint structure. [Background technology]

[0002] In the joining structure of the panel box described in Patent Document 1, a convex portion formed on one frame is fitted into a concave portion formed on the other frame, and the convex portion and the concave portion are joined with adhesive and rivets. In the frame structure of the housing described in Patent Document 2, embossed portions for positioning are formed on the frames used as pillars and the frames used as corner members, and the embossed portions are fitted together and fastened with rivets. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-101567 [Patent Document 2] Japanese Patent Application Publication No. 10-66208 Summary of the Invention [Problem to be solved by the invention]

[0004] Rivets, bolts, and nuts have many advantages over welding, such as being easier to work with and not damaging the base material, but because the head and opposite end protrude from the frame, there was room for improvement in terms of making them smaller and more space-saving. An object of the present invention is to reduce the size and space required in a frame joint structure by suppressing the protrusion of a fastener from a frame. [Means for solving the problem]

[0005] A frame joining structure according to one aspect of the present invention includes a pair of frames and a fastener. The pair of frames are plate-shaped and have through holes formed therein. The pair of frames are overlapped and the fastener is fitted into both of the through holes aligned in the axial direction. Each through hole is formed with an engagement claw that protrudes radially inward. The outer peripheral surface of the fastener is formed with an engagement groove that engages with each engagement claw and whose axial position changes as it advances along the circumferential direction. When the fastener is fitted into both of the through holes and rotated, each engagement claw deforms along the engagement groove, joining the pair of frames together by the fastener. [Effects of the Invention]

[0006] According to the present invention, when the fastener fitted into the through hole is rotated, the engaging claws deform and bite into the engaging grooves, generating a fastening force that joins the frames together. Therefore, since it is not a structure that clamps the frames together from both sides like rivets or bolts and nuts, the fastener does not protrude from the frame, making it possible to reduce the size and save space. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a frame joint structure. [Figure 2] FIG. 10 is a diagram showing each decomposed frame. [Figure 3] The images show the frames superimposed on each other. [Figure 4] FIG. 10 shows a pair of overlapping frames. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 10 is a view showing a deformed engagement claw. [Figure 8] FIG. [Figure 9] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are schematic and may differ from the actual product. Furthermore, the following embodiments exemplify devices and methods for embodying the technical concept of the present invention, and are not intended to limit the configuration to those described below. In other words, the technical concept of the present invention can be modified in various ways within the technical scope described in the claims.

[0009] <<Embodiment>> "composition" In the following description, the three mutually orthogonal directions are referred to as a width direction, a depth direction, and a length direction. The width direction and the depth direction are the two horizontal directions, and the length direction is the vertical direction. FIG. 1 is a diagram showing a frame joint structure 11. As shown in FIG. Here, the frame joint structure 11 is shown as viewed from the inside in the width direction, the inside in the depth direction, and the inside in the vertical direction. The frame joint structure 11 is used, for example, in the housing frame of an electrical equipment storage facility that stores various electrical equipment inside. The frame joint structure 11 includes a width frame 12, a depth frame 13, a vertical frame 14, a corner frame 15, and a fastener 16. The width frame 12, the depth frame 13, the vertical frame 14, and the corner frame 15 are formed by bending steel plates with a uniform thickness, which is approximately 6 mm in this example. The fastener 16 is formed from carbon steel or alloy steel for mechanical structures.

[0010] FIG. 2 is a diagram showing each decomposed frame. Here, each frame is shown as viewed from the inside in the width direction, the inside in the depth direction, and the inside in the vertical direction. The width frame 12 extends in the width direction and includes a width plate portion 21 and a width plate portion 22. The width plate portion 21 extends in the width direction and is made of a flat plate aligned in the width and depth directions, with the outer end in the width direction being cut at a 45-degree angle so that the outer end in the width direction extends toward the outer side in the depth direction. The width plate portion 22 extends in the width direction and is made of a flat plate aligned in the width and vertical directions, and is formed by bending the outer end in the depth direction of the width plate portion 21 toward the inner side in the vertical direction.

[0011] The depth frame 13 extends in the depth direction and includes a depth plate portion 23 and a depth plate portion 24. The depth plate portion 23 extends in the depth direction and is made of a flat plate that is aligned in the depth direction and width direction, and the outer end portion in the depth direction is cut at a 45-degree angle so that the outer end portion in the width direction extends toward the outer side in the depth direction. The depth plate portion 24 extends in the depth direction and is made of a flat plate that is aligned in the depth direction and vertical direction, and is formed by bending the outer end portion in the width direction of the depth plate portion 23 toward the inner side in the vertical direction. The vertical frame 14 extends in the vertical direction and includes a vertical plate portion 25 and a vertical plate portion 26. The vertical plate portion 25 extends in the vertical direction and is composed of a flat plate along the vertical and width directions. The vertical plate portion 26 extends in the vertical direction and is composed of a flat plate along the vertical and depth directions, and is formed by bending the vertical plate portion 25 from the outer end in the width direction toward the inside in the depth direction. The corner frame 15 is a right-angled isosceles triangle with the length of the side along the width direction and the length of the side along the depth direction being equal when viewed from the vertical direction.

[0012] Each of the width plate portions 21 and 22 has one through hole 31 formed therethrough in the thickness direction. Each of the depth plate portions 23 and 24 has one through hole 31 formed therethrough in the thickness direction. Each of the vertical plate portions 25 and 26 has one through hole 31 formed therethrough in the thickness direction. The corner frame 15 has two through holes 31 formed therethrough in the thickness direction. Each through hole 31 has two engaging claws 32 formed therein that protrude radially inward, and the two engaging claws 32 are formed 180 degrees apart in the circumferential direction and face each other.

[0013] The through holes 31 are all the same in shape and dimensions, except for the orientation of the engaging claws 32. That is, in the through holes 31 of the width plate portion 21, the engaging claws 32 protrude along the depth direction, and in the through holes 31 of the width plate portion 22, the engaging claws 32 protrude along the vertical direction. In the through holes 31 of the depth plate portion 23, the engaging claws 32 protrude along the width direction, and in the through holes 31 of the depth plate portion 24, the engaging claws 32 protrude along the vertical direction. In the through holes 31 of the vertical plate portion 25, the engaging claws 32 protrude along the vertical direction, and in the through holes 31 of the vertical plate portion 26, the engaging claws 32 protrude along the vertical direction. In the through holes 31 of the corner frame 15 close to the sides along the width direction, the engaging claws 32 protrude along the depth direction, and in the through holes 31 close to the sides along the depth direction, the engaging claws 32 protrude along the width direction.

[0014] When assembling each frame, first, the outer end of the width frame 12 in the width direction is butted against the outer end of the depth frame 13 in the depth direction. Then, the corner frame 15 is overlapped from the outside in the vertical direction onto the width board portion 21 and the depth board portion 23, the vertical board portion 25 is overlapped from the outside in the depth direction onto the width board portion 22, and the vertical board portion 26 is overlapped from the outside in the width direction onto the depth board portion 24. FIG. 3 shows the frames superimposed on each other. Here, the views of each frame are shown from the inside in the width direction, the inside in the depth direction, and the inside in the vertical direction. When the corner frame 15 is overlapped on the width frame 12 and the depth frame 13, the through holes 31 of the corner frame 15 are aligned axially with the through holes 31 of the width plate portion 21 and the through holes 31 of the depth plate portion 23, and the engaging claws 32 are also aligned when viewed from the axial direction. When the vertical frame 14 is overlapped on the width frame 12 and the depth frame 13, the through holes 31 of the vertical plate portion 25 and the through holes 31 of the vertical plate portion 26 are aligned axially with the through holes 31 of the width plate portion 22 and the through holes 31 of the depth plate portion 24, and the engaging claws 32 are also aligned when viewed from the axial direction.

[0015] Next, the two through holes 31 arranged in the axial direction will be described. In the following explanation, the through hole 31 of the depth plate portion 24 and the through hole 31 of the vertical plate portion 26 will be described, but since the other two through holes 31 aligned in the axial direction are similar, detailed explanations will be omitted. FIG. 4 is a diagram showing a pair of overlapping frames. FIG. 1(a) shows the overlapping depth plate portion 24 and vertical plate portion 26 as viewed from the outside in the width direction. The through hole 31 has an inner peripheral surface 34 that conforms to a reference circle 33, and two engagement claws 32 protrude radially inward from the reference circle 33 along the vertical direction. The diameter of the reference circle 33 is set to approximately 20 mm, as an example. The engagement claws 32 become thinner as they move radially inward as viewed in the axial direction. The through hole 31 is point-symmetrical as viewed in the axial direction, and has the same shape when rotated 180 degrees around the axis.

[0016] 1B shows a cross section A-A of the depth plate 24, passing through the center of the through-hole 31 and aligned in the width and vertical directions, as viewed from the outside in the depth direction. The engaging claws 32 of the depth plate 24 are parallel to the depth plate 24 and have a uniform thickness less than the thickness of the depth plate 24. Here, for example, the engaging claws 32 are approximately 1 / 3 (2 mm) of the thickness of the depth plate 24. When the depth plate 24 and the vertical plate 26 are overlapped, the opposing sides are referred to as the opposing inner sides, and the opposing opposite sides are referred to as the opposing outer sides. The engaging claws 32 of the depth plate 24 are formed so that the end surface 35 facing inward is positioned further outward than the inner surface 36 of the depth plate 24 facing inward. In other words, when viewed from the opposing inner side, the engaging claws 32 of the depth plate 24 are recessed from the inner surface 36 of the depth plate 24 facing inward. Therefore, the end surfaces 35 of the engaging claws 32 of the depth plate 24 and the engaging claws 32 of the vertical plate 26 are spaced apart. The engaging claws 32 of the depth plate portion 24 are formed so that the end faces 37 facing outward are flush with the outer faces 38 facing outward of the depth plate portion 24. The engaging claws 32 are formed by, for example, cutting. The through-hole 31 of the vertical plate portion 26 has a shape that is the inverse of the through-hole 31 of the depth plate portion 24 in the width direction when viewed from the depth direction, and therefore a detailed description thereof will be omitted. In other words, the through-hole 31 of the depth plate portion 24 and the through-hole 31 of the vertical plate portion 26, which are aligned in the axial direction, are line-symmetrical to each other when viewed from the surface direction of the depth plate portion 24 and the vertical plate portion 26.

[0017] FIG. 5 is a diagram showing the fastener 16. As shown in FIG. Here, the three mutually orthogonal directions are defined as the axial direction, the x direction, and the y direction. (a) in the figure is a perspective view of the fastener 16 as viewed from one axial direction, one x direction, and one y direction. (b) in the figure is a perspective view of the fastener 16 as viewed from one axial direction, the other x direction, and one y direction. (c) in the figure is a front view of the fastener 16 as viewed from the axial direction. (d) in the figure is a side view of the fastener 16 as viewed from one x direction. (e) in the figure is a side view of the fastener 16 as viewed from the other x direction.

[0018] The fastener 16 is a generally cylindrical member having an axial direction, and fits into both of the through holes 31 aligned in the axial direction. That is, the fastener 16 has an outer peripheral surface 41 that fits into the inner peripheral surfaces 34 of the two through holes 31, and has recesses 42 that are recessed radially inward along the engagement claws 32 when viewed from the axial direction. One recess 42 is formed on each side in the y direction. The axial dimension L of the fastener 16 is the same as the thickness of the overlapping depth plate portion 24 and vertical plate portion 26. Therefore, since the thickness t of each of the depth plate portion 24 and vertical plate portion 26 is 6 mm, the axial dimension of the fastener 16 is L = 12 mm.

[0019] The outer peripheral surface 41 of the fastener 16 is formed with spiral engagement grooves 43 that engage with the respective engagement pawls 32 and whose axial position changes as they move circumferentially. The engagement grooves 43 have a constant groove width, and their depth from the outer peripheral surface 41 is greater than the radial dimension of the engagement pawls 32. The direction in which the fastener 16 is rotated after being fitted into the through hole 31 is the fastening direction, which is set to be clockwise. Two engagement grooves 43 are formed on each side in the x direction. Each starts from the side of the recess 42 and extends circumferentially in the opposite direction to the fastening direction, i.e., counterclockwise. Therefore, on one side in the y direction, two engagement grooves 43 extend from one side in the x direction to the other side in the y direction, and on the other side in the y direction, two engagement grooves 43 extend from the other side in the x direction to one side in the y direction. At the start position where each engagement groove 43 starts from the side surface of the recess 42, it is positioned axially outward to a position where it just touches the axial end face, and is formed so that it moves inward as it progresses along the circumferential direction in the opposite direction to the fastening direction. At the end position where each engagement groove 43 extends in the circumferential direction, it is positioned axially inward, but is located short of the axial center. Therefore, the engagement groove 43 approaching from one side in the axial direction and the engagement groove 43 approaching from the other side in the axial direction do not come into contact with each other.

[0020] The fastener 16 has insertion portions 44 formed on both axial end surfaces for inserting a tool. The insertion portions 44 are grooves with a bottom and are shaped like a straight minus sign that is long in the x direction when viewed axially. When a tool is inserted into the insertion portion 44 and a rotational torque is applied in the fastening direction, the fastener 16 rotates clockwise while fitted into the through-hole 31. As a tool for rotating the fastener 16, for example, a torque wrench, T-type wrench, rotary power tool, or the like equipped with a tip tool such as a flat-head bit that fits into the insertion portion 44 is used. The fastener 16, like the through hole 31, is point-symmetric when viewed from the axial direction, and has the same shape when rotated 180 degrees around the axis. Furthermore, it is line-symmetric when viewed from the direction perpendicular to the axis, and has the same shape when flipped about the center line in the direction perpendicular to the axis.

[0021] FIG. 6 is a diagram showing the joining operation. (a) in the figure shows the state before joining. The fastener 16 is fitted into the through-hole 31 of the depth plate portion 24 and the through-hole 31 of the vertical plate portion 26. From this state, when a tool is inserted into the insertion portion 44 and a rotational torque is applied in the clockwise direction, which is the fastening direction, each engagement claw 32 enters the engagement groove 43. Because the engagement groove 43 is formed in a spiral shape, the engagement claws 32 deform inward along the engagement groove 43 as they bite into the fastener 16 as they rotate. In this way, a fastening force is generated, and the depth plate portion 24 and the vertical plate portion 26 are joined. (b) in the figure shows the state after joining. Here, the fastener 16 has been rotated about 90 degrees in the circumferential direction, and the engagement claws 32 are hidden inside the engagement groove 43.

[0022] FIG. 7 is a diagram showing the deformed engaging claw 32. As shown in FIG. Here, the fastening body 16 is omitted for clarity in illustrating the deformed engagement claw 32. (a) in the figure is a view of the depth plate portion 24 and the vertical plate portion 26 from the outside in the width direction. (b) in the figure is a view of the B-B cross section passing through the center of the through-hole 31 along the width and vertical directions, viewed from the outside in the depth direction. Because the engagement groove 43 is formed in a spiral shape, the engagement claw 32 deforms inwardly while twisting. This inward deformation acts as a fastening force that presses both the depth plate portion 24 and the vertical plate portion 26 inwardly. This joins the depth plate portion 24 and the vertical plate portion 26 together. The step between the end surface 35 of the engagement claw 32 facing inward and the inner surface 36 of each frame facing inward provides a deformation allowance that allows the engagement claw 32 to deform inwardly. The joints between the width plate portion 21 and the corner frame 15, the joint between the depth plate portion 23 and the corner frame 15, and the joint between the width plate portion 22 and the vertical plate portion 25 are similar, so detailed explanations will be omitted.

[0023] FIG. 8 is a diagram showing the housing frame 51. As shown in FIG. The housing frame 51 includes width frames 12, depth frames 13, vertical frames 14, and corner frames 15, which are combined to form a substantially rectangular parallelepiped. Specifically, the housing frame 51 includes four width frames 12 extending along the width direction, four depth frames 13 extending along the depth direction, four vertical frames 14 extending along the length direction, and eight corner frames 15 provided at the four corners on the bottom side and the four corners on the ceiling side. While the width frames 12, depth frames 13, and vertical frames 14 are shown to be approximately equal in length, in reality, they may differ. The frames are all joined together by fasteners 16.

[0024] <<Action and Effect>> Next, the main effects of the embodiment will be described. The frame joining structure 11 includes a pair of frames, such as a depth plate portion 24 and a vertical plate portion 26, and a fastener 16. The pair of frames are plate-shaped and have through holes 31 formed therein. The fastener 16 is fitted into both of the through holes 31, which are aligned axially when the pair of frames are stacked together. Each through hole 31 has an engagement claw 32 protruding radially inward. The outer peripheral surface 41 of the fastener 16 has an engagement groove 43 that engages with each engagement claw 32 and whose axial position changes as it advances circumferentially. When the fastener 16 is fitted into both through holes 31 and rotated, the engagement claws 32 deform along the engagement grooves 43, thereby joining the pair of frames together with the fastener 16. As a result, the engagement claws 32 deform and bite into the engagement grooves 43, generating a fastening force that joins the frames together. Therefore, since it does not have a structure that clamps the frames together from both sides like a rivet or a bolt / nut, the fastener 16 does not protrude from the frame, which makes it possible to reduce the size and save space.

[0025] The axial dimension of the fastener 16 is equal to or less than the thickness of the pair of overlapping frames, which eliminates the protrusion of the fastener 16 from the frames, enabling miniaturization and space saving. A plurality of engaging claws 32 are formed along the circumferential direction, thereby ensuring a sufficient fastening force. The engaging claws 32 are formed at equal intervals along the circumferential direction, thereby allowing the fastening force to be applied evenly along the circumferential direction.

[0026] When a pair of frames are overlapped, the opposing sides are set as opposing inner sides, and when the frame joining structure 11 is rotated after fitting the fasteners 16 into both through holes 31, each engaging claw 32 deforms toward the opposing inner side along the engaging groove 43. This generates a fastening force that presses the opposing inner sides, joining the pair of frames together. When a pair of frames are overlapped, the opposing sides that face each other are the opposing outer sides, and the engaging claws 32 are formed so that their thickness is less than the thickness of the frames and their end faces 35 facing inward are positioned on the opposing outer side of the inner faces 36 of the frames that face inward. This allows each engaging claw 32 to be deformed inward.

[0027] The engagement grooves 43 are formed so that the axial position of the engagement grooves 43 moves inward in the opposite direction to the circumferential direction of the rotation of the fastener 16. This allows the engagement claws 32 to be deformed inward in the opposite direction. The through hole 31 has an inner peripheral surface 34 that follows the reference circle 33, and the fastener 16 has an outer peripheral surface 41 that fits into the inner peripheral surface 34. This guides the rotation of the fastener 16 along the reference circle 33. The engaging claws 32 protrude radially inward from the reference circle 33, and the fastener 16 has recesses 42 formed therein that are recessed radially inward along the engaging claws 32 when viewed axially. This allows the fastener 16 to be fitted axially into the through-hole 31.

[0028] The fastener 16 is formed with an insertion portion 44 into which a tool for rotating the fastener 16 can be inserted. This allows the tool to be used to rotate the fastener 16 and perform fastening. By making the insertion portion 44 bottomed rather than penetrating in the axial direction, unnecessary thinning is suppressed and the strength of the fastener 16 can be ensured. Both of the through holes 31 aligned in the axial direction are formed to be line-symmetrical when viewed from the plane direction of the pair of frames. This allows the fastener 16 to be fitted into either of the two through holes 31.

[0029] The through hole 31 is formed to be point symmetrical when viewed from the axial direction, which allows the fastener 16 to be fitted into the through hole 31 without regard to the up-down or left-right orientation. The frame joint structure 11 is employed in a housing frame 51 that houses electrical equipment. The housing frame 51 that houses the electrical equipment is required to pack the electrical equipment at a high density and ensure an insulation distance, so it is particularly beneficial to reduce the protrusion of the fastener 16 from the frame to achieve size reduction and space saving.

[0030] Next, a comparative example will be described. As a comparative example, a pair of frames are generally joined together using rivets or bolts and nuts. Rivets and bolts and nuts have many advantages, such as being less difficult to work with than welding and not damaging the base material. However, because the head and opposite end protrude from the frame, there is room for improvement in terms of miniaturization and space saving. In particular, housing frames that house electrical equipment require high density of the electrical equipment and ensuring insulation distances, so joining using rivets or bolts and nuts has been an obstacle to miniaturization and space saving.

[0031] <<Variation>> In the embodiment, a configuration in which two engagement claws 32 are formed in one through hole 31 has been described, but the present invention is not limited to this. That is, for example, three or four engagement claws 32 may be formed in one through hole 31. FIG. 9 is a diagram showing a modified example. Figure (a) shows a configuration in which three engaging claws 32 are formed, and figure (b) shows a configuration in which four engaging claws 32 are formed. In either case, the engaging claws 32 are formed at equal intervals along the circumferential direction. In this way, by increasing the number of engaging claws 32, sufficient fastening force can be ensured. Furthermore, by forming multiple engaging claws 32 at equal intervals along the circumferential direction, the fastening force can be applied evenly along the circumferential direction.

[0032] In the embodiment, the outward-facing end face 37 of the engagement claw 32 is flush with the outward-facing outer surface 38 of the frame, but this is not limiting. That is, the end face 37 of the engagement claw 32 may be formed to be more inward than the outer surface 38 of the frame. This allows the engagement groove 43 of the fastener 16 to start slightly inward rather than just touching the axial end face. Therefore, the thickness of the portion of the fastener 16 that is outward at the start of the engagement groove 43 can be increased, thereby increasing its strength against the reaction force from the engagement claw 32.

[0033] In the embodiment, the insertion portion 44 has a minus shape, but is not limited to this. That is, the shape of the insertion portion 44 can be any shape, such as a cross shape, a square hole, a hexagonal hole, or a hexalobular shape. In the embodiment, the configuration in which the depth plate portion 24 and the vertical plate portion 26 are joined by one fastener 16 has been described, but this is not limited thereto, and they may be joined by two or more fasteners 16. The same applies to other joining portions. In the embodiment, the configuration in which the frames are joined without using any rivets or bolts and nuts has been described, but the present invention is not limited to this. That is, fastening using fasteners 16 may be performed in locations where protrusion from the frame is not permitted, and fastening using rivets or bolts and nuts may be performed in locations where protrusion from the frame is permitted.

[0034] Although the present invention has been described above with reference to a limited number of embodiments, the scope of the invention is not limited thereto, and modifications of the embodiments based on the above disclosure will be obvious to those skilled in the art. [Explanation of symbols]

[0035] 11...frame joining structure, 12...width frame, 13...depth frame, 14...vertical frame, 15...corner frame, 16...fastening body, 21...width plate portion, 22...width plate portion, 23...depth plate portion, 24...depth plate portion, 25...vertical plate portion, 26...vertical plate portion, 31...through hole, 32...engaging claw, 33...reference circle, 34...inner surface, 35...end face, 36...inner surface, 37...end face, 38...outer surface, 41...outer surface, 42...recess, 43...engaging groove, 44...insertion portion, 51...casing frame

Claims

1. a pair of plate-shaped frames each having a through hole formed therein; and a fastener that is fitted into both of the through holes that are aligned in the axial direction by overlapping the pair of frames, Each of the through holes is formed with an engaging claw that protrudes radially inward, An engagement groove is formed on the outer circumferential surface of the fastening body, and the engagement groove engages with each of the engagement claws, and the axial position of the engagement groove changes as the engagement groove advances along the circumferential direction. When the fasteners are fitted into both of the through holes and rotated, the engaging claws are deformed along the engaging grooves, and the pair of frames are joined by the fasteners, A frame joining structure characterized in that a plurality of the engaging claws are formed along the circumferential direction.

2. 2. The frame joint structure according to claim 1, wherein the axial dimension of the fastening body is equal to or less than the thickness of the pair of overlapping frames.

3. 2. The frame joining structure according to claim 1, wherein the engaging claws are formed at equal intervals along the circumferential direction.

4. When the pair of frames are overlapped, the sides facing each other are defined as facing inner sides, A frame joining structure described in any one of claims 1 to 3, characterized in that when the fasteners are inserted into both of the through holes and rotated, each of the engaging claws deforms toward the opposite inward direction along the engaging groove.

5. When the pair of frames are overlapped, the opposite sides facing each other are defined as facing outer sides, The frame joining structure according to claim 4, characterized in that the engaging claw has a thickness less than the thickness of the frame, and the end surface facing inward is formed so as to be positioned outward of the inner surface of the frame facing inward.

6. The frame joining structure according to claim 4 or 5, characterized in that the engagement groove is formed so that its axial position moves toward the opposing inner side as it moves in the opposite direction to the direction in which the fastening body is rotated along the circumferential direction.

7. The through hole has an inner circumferential surface that follows a reference circle, The frame joint structure according to any one of claims 1 to 6, characterized in that the fastener has an outer peripheral surface that fits into the inner peripheral surface.

8. The engaging claws protrude radially inward from the reference circle, The frame joining structure according to claim 7, characterized in that the fastening body is formed with a recess that is recessed radially inward along the engaging claw when viewed from the axial direction.

9. A frame joining structure as described in any one of claims 1 to 8, characterized in that the fastener is formed with an insertion portion into which a tool for rotating the fastener can be inserted.

10. A frame joint structure described in any one of claims 1 to 9, characterized in that both of the through holes aligned in the axial direction are formed so as to be linearly symmetrical when viewed from the surface direction of the pair of frames.

11. The frame joint structure according to any one of claims 1 to 10, characterized in that the through holes are formed so as to be point symmetric when viewed in the axial direction.

12. 12. The frame joint structure according to claim 1, which is used in a housing frame that houses an electric device therein.

Images