Fastening structure

Abstract

To provide a fastening structure which is firmly mounted to one mounted member and to which the other mounted member is easily mounted.SOLUTION: A fastening structure 20 has a first mounted member 1 to which a second mounted member 4 is connected via a clip 21 in the state of facing it at a space. The clip 21 consists of two members, a grommet member 24 and a pin member 37. A first engagement part 22 of the clip 21 is mounted to the first mounted member 1 in a non-diameter-enlarged state, and when the pin member 37 is pushed therein to cause the first engagement part 22 to be deformed into a diameter-enlarge state, the clip 21 engages with the first mounted member 1. A second mounted member 4 is mounted to a second engagement part 23 of the clip 21, and when the clip 21 is rotated, the clip 21 engages with the second mounted member 4.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The present invention relates to a fastening structure for attaching one member to another member. [Background technology]

[0002] Conventionally, an undercover of an automobile has an opening for exposing a jack-up point, and the opening is covered by a lid cover. The lid cover is attached to a side sill cover or the like via a clip, and is removed when jacking up the automobile. As such, a clip used to attach and detach one member (e.g., a lid cover) to another member (e.g., a side sill cover) is disclosed, for example, in the technology described in Patent Document 1 below (hereinafter, the technology described in Patent Document 1 will be referred to as the "Publicly Known Invention 1").

[0003] The clip according to the invention of the first prior art document is interposed between two panels and has an insertion portion inserted into a hole in one panel and a fastening portion inserted into a hole in the other panel. First, the insertion portion is attached to one panel, and then the other panel is attached to the fastening portion. Specifically, the clip according to the first prior art document is made of resin, and the insertion portion has an elastic piece that is slightly larger than the hole in one panel. The elastic piece elastically deforms slightly when passed through the hole and returns to its original shape after passing through the hole, thereby engaging with the edge of the hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-115148 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as mentioned above, in the invention of the first prior art document, the elastic piece is engaged with the edge of the hole due to a slight difference in size before and after elastic deformation, so the elastic piece easily comes off the hole. Also, after the insertion portion is attached to one panel, when the other panel is attached to the fastening portion, the insertion portion may rotate around the axis, making it difficult for the other panel to attach to the fastening portion.

[0006] The present invention has been proposed in view of the above circumstances, and aims to provide a fastening structure that can be firmly attached to one attached member and can easily be attached to the other attached portion. [Means for solving the problem]

[0007] In order to achieve the above object, the fastening structure of the present invention provides a first fastening member engagement state in which the first fastening member is inserted into a first fastening hole formed in a first fastening member and engaged with the first fastening member, and a second fastening member engagement state in which the second fastening member is inserted into a second fastening hole formed in a second fastening member and engaged with the second fastening member, thereby fastening the second fastening member to the first fastening member in a facing relationship. The fastening structure has a grommet member and a pin member that are connected to each other in advance, and the grommet member has an insertion hole formed in the grommet member and is attached to the first fastening member. the pin member has a main body portion that is inserted into the first mounting hole portion, a plurality of legs that extend from around the insertion hole and are inserted into the first mounting hole portion, and an arm portion that is formed on the opposite side of the main body portion from the legs and is inserted into the second mounting hole portion, and the pin member has a shaft that is inserted into the insertion hole, and a first engagement portion that is composed of the legs and the shaft is inserted into the first mounting hole portion in a non-expanded state that allows it to be inserted into the first mounting hole portion, and the shaft is pushed into the main body portion and the legs are expanded to an expanded state, thereby engaging with the first mounting member.

[0008] The fastening structure according to the present invention is characterized in that the shaft portion has a positioning protrusion that protrudes outward from the leg portion in the non-diameter-expanded state.

[0009] The fastening structure of the present invention is characterized in that, in the non-expanded state, the positioning protrusion is continuous from the tip of the leg to the main body, and a groove portion is formed at the end of the positioning protrusion on the main body side, which does not protrude outward beyond the leg in the expanded state.

[0010] The fastening structure of the present invention is characterized in that a pair of arms protrude outward from the main body portion in directions away from each other, and in a second attachment member temporary holding state in which the arms are inserted into the second attachment hole portion and positioned on the opposite side of the first attachment member to the second attachment member, and in the first attachment member engagement state, the arms engage with the second attachment member by forward rotation around the first engagement portion as an axis, thereby entering the second attachment member engagement state.

[0011] The fastening structure of the present invention is characterized in that the arm portion has a mating protrusion that protrudes toward the second workpiece when the second workpiece is temporarily held, and when the second workpiece is engaged, the mating protrusion mates with the second workpiece.

[0012] The fastening structure according to the present invention is characterized in that the pin member has a head and a shaft portion extending from the head, and the head has an inclined surface portion that slopes outward as it approaches the shaft portion.

[0013] The fastening structure of the present invention is characterized in that the first attached member and / or the second attached member have a rotation regulating portion that regulates the forward rotation when the second attached member is in an engaged state, or that regulates the reverse rotation opposite to the forward rotation when the second attached member is in a temporarily held state.

[0014] The fastening structure of the present invention is characterized in that the second attached member has a guide portion that guides the sliding of the arm portion relative to the second attached member during the process from the second attached member temporary holding state to the second attached member engagement state.

[0015] The fastening structure according to the present invention is characterized in that the guide portion is an inclined surface that rises from the edge of the second mounting hole portion along the direction of forward rotation.

[0016] The fastening structure according to the present invention is characterized in that the guide portion is formed with a mating recess into which the mating protrusion is mated.

[0017] The fastening structure according to the present invention is characterized in that a slit into which the positioning protrusion is engaged is formed on the edge of the first mounting hole portion. [Effects of the Invention]

[0018] The fastening structure of the present invention is a fastening structure in which a second workpiece is attached to a first workpiece by being inserted into a first mounting hole formed in the first workpiece and engaging with the first workpiece, and by being inserted into a second mounting hole formed in the second workpiece and engaging with the second workpiece, and the fastening structure comprises a grommet member and a pin member which are connected to each other in advance, the grommet member having a main body portion with an insertion hole formed therein and attached to the first workpiece, a plurality of legs extending from around the insertion hole and inserted into the first mounting hole, and an arm portion formed on the opposite side of the main body from the legs and inserted into the second mounting hole, the pin member having a shaft portion inserted into the insertion hole, the first engagement portion composed of the legs and shaft portion is inserted into the first mounting hole in a non-expanded state so that it can be inserted into the first mounting hole, and the shaft portion is pushed against the main body portion to expand the legs and assume an expanded diameter state, thereby achieving the first mounting hole engaging state.

[0019] That is, the clip is composed of two components: a grommet member and a pin member (hereinafter, the component formed by connecting the grommet member and the pin member will be referred to as the "clip"). When the first engagement portion is inserted into the first mounting hole, the shank of the pin member pushes the legs of the grommet member apart from the inside, causing the first engagement portion to enter an expanded state and the fastening structure to enter an engaged state with the first mounting member. The first engagement portion does not engage with the first mounting member solely through elastic deformation of the legs; rather, because the legs are pushed apart from the inside by the shank while in an elastically deformed state, the first engagement portion does not unintentionally return to its non-expanded state. Therefore, the first engagement portion is firmly attached to the first mounting member, and the engaged state with the first mounting member is robust. This also prevents unintentional rotation of the clip when the second mounting member is attached, making it easy to attach the second mounting member.

[0020] In the fastening structure according to the present invention, the shank has a positioning protrusion that protrudes outward from the leg when in a non-diameter-expanded state. If a slit or the like into which the positioning protrusion is engaged is formed on the edge of the first mounting hole, the orientation of the first engaging portion when inserted into the first mounting hole is determined by the positioning protrusion and the slit. This prevents the first engaging portion from being inserted into the first mounting hole in an incorrect orientation.

[0021] In the fastening structure according to the present invention, in the non-expanded state, the positioning protrusion extends from the tip of the leg to the main body, and the end of the positioning protrusion facing the main body is formed with a groove that does not extend beyond the leg in the expanded state. In the non-expanded state, the positioning protrusion engages with a slit or the like in the first mounting hole, preventing unintended rotation when attaching the second mounting member, thereby facilitating attachment of the second mounting member. Meanwhile, in the expanded state, the positioning protrusion passes through a slit or the like in the first mounting hole, and the groove is positioned in the slit or the like, preventing the positioning protrusion from engaging with the slit or the like, allowing the clip to rotate forward. When the clip rotates forward, the step between the groove and the positioning protrusion shifts from the slit or the like. Even if the clip is pulled up, the step engages with the first mounting member. This prevents the clip from coming off the first mounting member.

[0022] In the fastening structure according to the present invention, a pair of arms protrude outward from the main body in directions away from each other. In a second workpiece provisionally held state, in which the arms are inserted into the second mounting hole and positioned on the opposite side of the first workpiece relative to the second workpiece, and in a first workpiece engaged state, forward rotation about the first engagement portion engages the arms with the second workpiece, thereby achieving a second workpiece engaged state. In other words, forward rotation of the clip transitions from the second workpiece provisionally held state to the second workpiece engaged state. Because engagement occurs through rotation in a direction different from insertion, the second workpiece engaged state is more robust than when engagement occurs through insertion alone.

[0023] In the fastening structure according to the present invention, the arm portion has a mating projection that protrudes toward the second workpiece when the second workpiece is in the temporary holding state, and the mating projection is mated with the second workpiece when the second workpiece is in the engaged state. Therefore, the second workpiece is in a robust engaged state. For example, unintended rotation due to shocks such as vibrations is prevented.

[0024] In the fastening structure according to the present invention, the pin member has a head and a shaft extending from the head, and the head has an inclined surface that slopes outward toward the shaft. When the second member is attached, the head is passed through the second attachment hole, and the edge of the second attachment hole is guided along the inclined surface. This makes it easy to attach the second member.

[0025] In the fastening structure according to the present invention, the first workpiece and / or the second workpiece have a rotation restricting portion that restricts forward rotation when the second workpiece is in the engaged state, or restricts reverse rotation in the direction opposite to the forward rotation when the second workpiece is in the temporarily held state. This prevents unintended rotation of the clip and prevents the second workpiece from coming off.

[0026] In the fastening structure according to the present invention, the second workpiece has a guide portion that guides the sliding of the arm portion relative to the second workpiece as the second workpiece transitions from a provisionally held state to an engaged state. The arm portion moves along the guide portion, promoting forward rotation. This allows the second workpiece to be easily attached.

[0027] In the fastening structure according to the present invention, the guide portion is an inclined surface that rises from the edge of the second mounting hole portion in the direction of forward rotation. Because the arm portion slides smoothly along the inclined surface, excessive stress is not generated, and forward rotation is smooth. Therefore, the second mounting member can be easily attached.

[0028] In the fastening structure according to the present invention, the guide portion is formed with a mating recess into which the mating protrusion fits, so that the engagement state of the second mounted member is robust.

[0029] In the fastening structure according to the present invention, a slit is formed on the edge of the first mounting hole portion, into which the positioning protrusion is engaged. The positioning protrusion and the slit determine the orientation of the first engaging portion when inserted into the first mounting hole portion. This prevents the first engaging portion from being inserted into the first mounting hole portion in an incorrect orientation. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is an exploded perspective view of a clip that constitutes a fastening structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a clip that constitutes the fastening structure according to the embodiment of the present invention. [Figure 3] FIG. 3 is a top view of a clip that constitutes the fastening structure according to the embodiment of the present invention. [Figure 4] FIG. 4 is a front view of a clip that constitutes a fastening structure according to an embodiment of the present invention. [Figure 5] FIG. 5 is a side view of a clip that constitutes a fastening structure according to an embodiment of the present invention. [Figure 6] FIG. 6 is a bottom view of a clip that constitutes the fastening structure according to the embodiment of the present invention. [Figure 7] FIG. 7 is a front view of a clip constituting the fastening structure according to the embodiment of the present invention after deformation. [Figure 8] FIG. 8 is a side view of a clip constituting the fastening structure according to the embodiment of the present invention after deformation. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 3, showing a clip that constitutes the fastening structure according to the embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view of the same configuration as FIG. 9, showing the clip constituting the fastening structure according to the embodiment of the present invention after deformation. [Figure 11] FIG. 11 is a perspective view of a first attached member that constitutes the fastening structure according to the embodiment of the present invention. [Figure 12] FIG. 12 is a perspective view of a second attached member that constitutes the fastening structure according to the embodiment of the present invention. [Figure 13] FIG. 13 is a front view showing a first fastening step in the fastening structure according to the embodiment of the present invention. [Figure 14] FIG. 14 is a front cross-sectional view showing a first fastening step using the fastening structure according to the embodiment of the present invention. [Figure 15]15 is a cross-sectional view taken along the line XV-XV in FIG. 13, showing a first fastening step performed by the fastening structure according to the embodiment of the present invention. [Figure 16] FIG. 16 is a front view showing a second fastening step in which the fastening structure according to the embodiment of the present invention is fastened. [Figure 17] FIG. 17 is a front cross-sectional view showing a second fastening step using the fastening structure according to the embodiment of the present invention. [Figure 18] 18 is a cross-sectional view taken along the line XVIII-XVIII in FIG. 13, showing a second fastening step by the fastening structure according to the embodiment of the present invention. [Figure 19] FIG. 19 is a front view showing a third fastening step in the fastening structure according to the embodiment of the present invention. [Figure 20] FIG. 20 is a top view of a third fastening step showing a third fastening step by the fastening structure according to the embodiment of the present invention. [Figure 21] FIG. 21 is a front view showing a fourth fastening step of the fastening structure according to the embodiment of the present invention. [Figure 22] FIG. 22 is a top view of a fourth fastening step illustrating a fourth fastening step by the fastening structure according to the embodiment of the present invention. [Figure 23] 23 is a cross section taken along line XXIII-XXIII of FIG. 22, showing a fourth fastening step front cross section illustrating a fourth fastening step by the fastening structure according to the embodiment of the present invention. [Figure 24] FIG. 24 is a front view showing a fifth fastening step of the fastening structure according to the embodiment of the present invention. [Figure 25] FIG. 25 is a top view of a fifth fastening step illustrating a fifth fastening step by the fastening structure according to the embodiment of the present invention. [Figure 26] FIG. 26 is a cross section taken along line XXVI-XXVI of FIG. 25, and is a front cross-sectional view of a fifth fastening step showing a fifth fastening step by the fastening structure according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] A fastening structure according to an embodiment of the present invention will be described below with reference to the drawings. In the fastening structure 20 according to this embodiment, a first workpiece 1 such as a sill cover (see FIG. 11) is attached to a second workpiece 4 such as a lid cover (see FIG. 12) in a facing position with a gap between them, and the workpieces 1 and 4 are connected via a clip 21 (see FIGS. 13 to 26). The clip 21 is composed of two members, a grommet member 24 and a pin member 37 (see FIG. 1), and the grommet member 24 and the pin member 37 are connected to each other in advance (see FIG. 2). The grommet member 24 and the pin member 37 move and deform relative to each other while connected (see FIGS. 3 to 10). In the following description, the direction in which the pin member 37 is pushed into the grommet member 24 is referred to as "down," the direction in which the pin member 37 is pulled out of the grommet member 24 is referred to as "up," and the sides perpendicular to the up-down direction are referred to as "right," "left," "front," and "back," respectively (see FIG. 1).

[0032] 1 and 2, clip 21 is used with the two members connected in advance. As shown in Fig. 1, pin member 37 has a head portion 38, a shaft portion 40 extending from head portion 38 and connecting to grommet member 24, and a pin flange portion 50 formed between head portion 38 and shaft portion 40 to restrict the range of motion of pin member 37 relative to grommet member 24.

[0033] An inclined surface portion 39 is formed on the upper surface of the head portion 38. The inclined surface portions 39 are a pair and are inclined outward in the front-rear direction as they extend downward, which is the direction toward the shaft portion 40. The pin flange portion 50 has a flat plate shape and is disposed directly below the head portion 38.

[0034] The shaft portion 40 is connected to the underside of the pin flange portion 50 and extends downward. The outer surface of the shaft portion 40 is formed with guide protrusions 41 and guide grooves 46 that guide the movement of the pin member 37 relative to the grommet member 24, as well as raised portions 47 for deforming the grommet member 24. The guide protrusions 41 protrude outward in all four directions (front, rear, left, and right) and extend linearly from the pin flange portion 50 to the lower end 49 of the shaft portion 40. The left and right guide protrusions 41 are positioning protrusions 42 that protrude further than the front and rear guide protrusions 41, while the front and rear guide protrusions 41 are non-positioning protrusions 45. The positioning protrusions 42 continue from the pin flange portion 50 to the lower end 49, and a groove 43 is formed at the boundary with the pin flange portion 50. The groove 43 is recessed toward the center of the shaft portion 40 more than the positioning protrusions 42. A step 44 is formed at the boundary between the positioning protrusion 42 and the groove 43. The non-positioning protrusion 45 continues from the pin flange portion 50 to the lower end 49.

[0035] The guide groove portion 46 is formed between the guide protrusions 41, extending from the pin flange portion 50 to the lower end portion 49 of the shaft portion 40. The raised portion 47 is formed in a part of the middle of the guide groove portion 46, and is raised laterally outward more than other parts of the guide groove portion 46. A part of the raised portion 47 is recessed, and a locking groove 48 is formed.

[0036] The grommet member 24 has a main body portion 25 to which the pin member 37 is connected, a plurality of leg portions 31 extending from the main body portion 25 and inserted into the first attached member 1, and arm portions 34 formed on the main body portion 25 and inserted into the second attached member 4.

[0037] The main body 25 has a disk-shaped base plate 26, a peripheral wall 28 rising from the circumferential edge of the base plate 26, and a main body flange 29 extending from the peripheral wall 28. The base plate 26 has an insertion hole 27 formed therein into which a shaft 40 of a pin member 37 is inserted. The insertion hole 27 has a cross shape that follows the shape of the shaft 40 of the pin member 37, which has four guide protrusions 41. The peripheral wall 28 has an annular shape that follows the circumference of the base plate 26. There are a pair of main body flanges 29, which extend outward in the front and rear directions from the lower end of the peripheral wall 28.

[0038] The leg portions 31 extend downward from the periphery of the insertion hole 27. An internal protrusion 33 that protrudes inward is formed on the inside of the tip portion 32, which is the lower end of the leg portion 31. A pair of arm portions 34 are formed on the opposite side of the body portion 25 from the leg portions 31. The arm portions 34 protrude outward from the upper end of the peripheral wall portion 28 to the left and right, in directions away from each other. The right arm portion 34 is formed with a restricting protrusion 35 that protrudes downward. The underside of the restricting protrusion 35 is flat. The left arm portion 34 is formed with a mating protrusion 36 that protrudes downward. The mating protrusion 36 is approximately hemispherical and protrudes further than the restricting protrusion 35 (see Figure 4).

[0039] The shaft portion 40 of the pin member 37 is inserted into the insertion hole 27 of the grommet member 24 from above, and the pin member 37 is connected to the grommet member 24 to form the clip 21. In the clip 21, the leg portions 31 and the shaft portion 40 form a first engagement portion 22, and the head portion 38 of the pin member 37 and the arm portions 34 of the grommet member 24 form a second engagement portion 23. As shown in FIGS. 2 to 6, when the pin member 37 is in its uppermost position relative to the grommet member 24, the first engagement portion 22 is in a non-diameter-expanded state. In the non-diameter-expanded state, the leg portions 31 are in an initial position extending straight downward, and the leg portions 31 are not pushed outward laterally. As shown in FIGS. 7 to 10, when the pin member 37 is in its lowermost position relative to the grommet member 24, the first engagement portion 22 is in an expanded state. In the expanded diameter state, the shaft portion 40 is pressed against the main body portion 25, and the leg portions 31 are pushed outward and laterally.

[0040] 2 to 6, the guide protrusions 41 of the pin member 37 are disposed between the leg portions 31 of the grommet member 24, and are continuous from the main body portion 25 of the grommet member 24 to the tip portions 32 of the leg portions 31. In the non-diameter-expanded state, the positioning protrusions 42 of the guide protrusions 41 protrude outward to the left and right beyond the leg portions 31. The grooves 43 are formed at the ends of the positioning protrusions 42 on the main body portion 25 side, and therefore, in the non-diameter-expanded state, the grooves 43 are disposed inside the main body portion 25 (see FIG. 14). On the other hand, the non-positioning protrusions 45 of the guide protrusions 41 do not protrude beyond the leg portions 31.

[0041] 7 to 10, when the pin member 37 is pushed downward in the non-diameter-expanded state, in the first engagement portion 22, as the shaft portion 40 descends, the raised portion 47 of the shaft portion 40 pushes the internal protrusion 33 of the leg portion 31 laterally outward, causing the leg portion 31 to expand laterally outward. When the pin flange portion 50 of the pin member 37 abuts against the base plate portion 26 of the grommet member 24, the descent of the pin member 37 is restricted, and at the same time, the internal protrusion 33 is locked in the locking groove 48 of the raised portion 47. In this way, the first engagement portion 22 enters the diameter-expanded state.

[0042] Since the groove portion 43 of the pin member 37 is formed at the end of the grommet member 24 on the main body portion 25 side, in the expanded diameter state, the groove portion 43 is exposed below the main body portion 25 and does not protrude from the leg portion 31 of the grommet member 24 (see Figure 17).

[0043] The clip 21 is configured as described above. Next, the first and second members 1 and 4 connected by the clip 21 will be described with reference to the drawings.

[0044] As shown in Figure 11, a portion of the first member 1 is plate-shaped. That is, the first member 1 has a plate-shaped portion in part. The first member 1 has a first mounting hole 2 formed therein. The first mounting hole 2 is approximately circular, but is not a perfect circle because a slit 3 is formed in part of it. The first engagement portion 22 of the clip 21 is inserted into the first mounting hole 2, and the positioning protrusion 42 of the pin member 37 is engaged in the slit 3.

[0045] As shown in FIG. 12 , a portion of the second attachment member 4 is plate-shaped. That is, the second attachment member 4 has a plate-shaped portion. The second attachment member 4 has a second attachment hole 5 formed therein, and a guide portion 8 and a rotation restricting portion 10 are formed around the second attachment hole 5. The second engagement portion 23 of the clip 21 is inserted into the second attachment hole 5. Therefore, the second attachment hole 5 has a shape that matches the second engagement portion 23, and includes a circular hole 6 that matches the shape of the main body 25 and peripheral wall 28 of the grommet member 24, and a rectangular hole 7 that matches the shape of the arm 34 of the grommet member 24. The guide portion 8 facilitates rotation of the clip 21. The guide portion 8 is a pair of upwardly inclined surfaces that curve from the edge of the rectangular hole 7 along a circumference centered on the center of the circular hole 6. Since the guide portion 8 is a groove, the base of the guide portion 8 is located deeper than the upper surface in the thickness direction of the workpiece 4, and the peak of the guide portion 8 is located near the upper surface. A mating recess 9 is formed at the peak of the guide portion 8. The mating recess 9 is hemispherical and recessed, following the shape of the mating protrusion 36 of the arm portion 34. The rotation restricting portion 10 restricts unwanted rotation of the clip 21. There is a pair of rotation restricting portions 10, and they are arranged on the circumference of the circular hole portion 6, beyond the mating protrusion 36. The rotation restricting portions 10 protrude.

[0046] Each of the workpieces 1 and 4 is configured as described above. Next, the use procedure, operation, and effects of the fastening structure 20 will be described with reference to the drawings. Before being attached to each of the workpieces 1 and 4, the clip 21 has the first engagement portion 22 in a non-expanded state (see FIGS. 2 to 7). When the clip 21 is attached to the first workpiece 1, it enters a first workpiece temporary-holding state (see FIGS. 13 to 15). When the first engagement portion 22 is deformed to an expanded state in this state, the clip 21 engages with the first workpiece 1 and enters a first workpiece-engaged state (see FIGS. 16 to 18). Next, when the second workpiece 4 is attached to the clip 21, it enters a second workpiece-temporarily-held state (see FIGS. 19 and 20). When the clip 21 is rotated in this state, the clip 21 engages with the second workpiece 4 and enters a second workpiece-engaged state (see FIGS. 21 to 26).

[0047] <First attachment member temporarily held state> As shown in Figures 13 to 15, the first engagement portion 22 in the non-expanded state is inserted into the first mounting hole 2 of the first mounting member 1, thereby establishing a first mounting member temporarily held state. In the first mounting member temporarily held state, the main body 25 of the grommet member 24 is attached to the upper surface of the first mounting member 1. The first engagement portion 22 in the non-expanded state can be inserted into the first mounting hole 2 because the leg portions 31 are not expanded. The positioning protrusion 42 of the pin member 37 protrudes laterally outward from the leg portions 31 of the grommet member 24, so the positioning protrusion 42 can pass through the slit 3 portion of the first mounting hole 2. Therefore, the orientation of the first engagement portion 22 when inserted into the first mounting hole 2 is determined by the positioning protrusion 42 and the slit 3. This prevents the first engagement portion 22 from being inserted into the first mounting hole 2 in an incorrect orientation. Furthermore, when the positioning protrusion 42 is engaged with the slit 3, unintentional rotation of the clip 21 is prevented when the second workpiece 4 is attached and the second workpiece 4 is temporarily held. Therefore, the second workpiece 4 can be attached easily.

[0048] <First mounted portion engaged state> As shown in Figures 16 to 18, in the first workpiece provisionally held state, the first engagement portion 22 enters an expanded diameter state, thereby entering a first workpiece engaged state. When the pin member 37 is pushed into the grommet member 24 in the first workpiece engaged state, the shank 40 causes the legs 31 of the grommet member 24 to expand laterally outward, resulting in the first engagement portion 22 entering an expanded diameter state. Because the legs 31 are elastically deformed and pushed outward from the inside by the shank 40, the first engagement portion 22 does not unintentionally return to its non-expanded diameter state. Therefore, the first engagement portion 22 is firmly attached to the first workpiece 1, and the first workpiece engaged state is robust. This prevents unintentional rotation of the clip 21 when the second workpiece 4 is attached, making it easy to attach the second workpiece 4.

[0049] <Second attached member temporarily held state> As shown in Figures 19 and 20, the second engagement portion 23 is inserted into the second mounting hole 5 of the second mounting member 4, thereby establishing a second mounting member temporary holding state. At this time, the head 38 of the pin member 37 is passed through the second mounting hole 5, and the edge of the second mounting hole 5 is guided along the inclined surface 39 of the head 38. This facilitates mounting of the second mounting member 4. In the second mounting member temporary holding state, the arm 34 of the grommet member 24 is positioned on the upper surface of the second mounting member 4, opposite the first mounting member 1. The engagement protrusion 36 and the restricting protrusion 35 of the arm 34 protrude downward from the upper surface of the second mounting member 4. The engagement protrusion 36 is positioned within the rectangular hole 7 of the second mounting hole 5 and is adjacent to the base of the guide portion 8. The restricting protrusion 35 is positioned above the rectangular hole 7 of the second mounting hole 5.

[0050] As shown in Figures 21 to 23, in the first attachment member engaged state (expanded diameter state), the positioning protrusion 42 passes through the slit 3 of the first attachment hole portion 2, and the groove portion 43 is disposed in the slit 3 (see Figure 18), allowing the clip 21 to rotate forward (clockwise in Figure 22) around the first engagement portion 22. Forward rotation of the clip 21 transitions from the second attachment member temporarily held state to the second attachment member engaged state. Because the guide portion 8 of the second attachment member 4 is an inclined surface that rises in the direction of forward rotation, when the clip 21 rotates forward from the second attachment member temporarily held state to the second attachment member engaged state, the engagement protrusion 36 of the grommet member 24 is guided along the guide portion 8 to the top of the guide portion 8. The engagement protrusion 36 moving along the guide portion 8 promotes forward rotation. In particular, since the engaging projection 36 slides smoothly along the inclined surface, excessive stress is not generated, and forward rotation is smooth. Therefore, the second mounted member 4 can be mounted easily.

[0051] Since the mating protrusion 36 of the grommet member 24 is positioned within the rectangular hole portion 7 of the second mounting hole portion 5, even if an external force is applied in a reverse rotation direction opposite to the forward rotation (counterclockwise direction in Figure 22), the mating protrusion 36 will come into contact with the edge of the rectangular hole portion 7 (see Figure 19), thereby preventing unintended reverse rotation of the clip 21.

[0052] As described above, when the clip 21 is in the first attached member engaged state and the second attached member temporarily held state, it rotates forward and the second engagement portion 23 engages with the second attached member 4, thereby achieving the second attached member engaged state. Because the second engagement portion 23 engages with the second attached member 4 by rotation in a direction different from that of insertion into the second attachment hole portion 5, the second attached member engaged state is more robust than when engagement occurs by insertion alone.

[0053] <Second mounted member engaged state> As shown in Figures 24 to 26, when the clip 21 is rotated approximately 90 degrees forward from the second workpiece temporary holding state, the mating projection 36 of the grommet member 24 engages with the mating recess 9 of the guide portion 8 at the top of the guide portion 8 of the second workpiece 4. Therefore, the second workpiece engagement state is robust. When the clip 21 rotates forward, the step 44 at the boundary between the groove 43 of the pin member 37 and the positioning projection 42 shifts from the slit 3 of the first workpiece 2. If the clip 21 is pulled up in this state, the step 44 engages with the first workpiece 1 (see Figure 26). This prevents the clip 21 from coming off the first workpiece 1.

[0054] When clip 21 rotates forward, rotation restricting portion 10 is located on the circular orbit of arm portion 34 (see FIG. 25). Therefore, even if an additional external force is applied in the direction of forward rotation of clip 21 in the second attached member engaged state, restricting protrusion 35 and engaging protrusion 36 will come into contact with rotation restricting portion 10, thereby restricting unintended forward rotation of clip 21.

[0055] In another embodiment of the present invention, the front and rear guide protrusions of the pin member are positioning protrusions. In another embodiment, all of the guide protrusions on the front, rear, left and right sides of the pin member are positioning protrusions. In another embodiment, the guide protrusions on either the front, rear, left or right of the pin member are the positioning protrusions. In other embodiments, the inclined surface portion has a single surface or a plurality of surfaces, such as three or more. The inclined surface portion may be, for example, a cone or a polygonal shape, such as a triangular pyramid. In another embodiment, the head of the pin member does not have an inclined surface portion. In other embodiments, the grommet member may have any number of arms. In another embodiment, the grommet member has a restricting protrusion formed on the right arm and a mating protrusion formed on the left arm. In another embodiment, the arms of the grommet member protrude outwardly in the front and rear directions. In another embodiment, the grommet member has mating projections formed on both arms. In another embodiment, the shape of the mating protrusion in the grommet member is arbitrary, for example, the cross section is semicircular (so-called semicircular), etc. In this case, the mating recess of the second attached member also has a shape that follows the shape of the mating protrusion. In another embodiment, the grommet member does not have a mating protrusion, and the second attachment member does not have a mating recess. In this case, the arm portion of the grommet member contacts and slides against the second attachment member, and the arm portion engages with the second attachment member. In another embodiment, the first workpiece has a rotation restricting portion that is located on the upper surface of the first workpiece and on the circular orbit of the main body flange when the clip rotates, and the main body flange abuts against the rotation restricting portion, thereby restricting unintended forward or reverse rotation of the clip. In another embodiment, when the clip rotates in the reverse direction, the restricting protrusion and / or the engaging protrusion of the arm portion comes into contact with the rotation restricting portion, thereby restricting the unintended reverse rotation of the clip. In another embodiment, the first and second workpieces have a rotation restricting portion. In another embodiment, the second attachment member does not have a rotation restricting portion. In another embodiment, the guide portion of the second attachment member is not an inclined surface. In another embodiment, the second attachment member does not have a guide portion.

[0056] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made to the present invention without departing from the scope of the claims. [Explanation of symbols]

[0057] 1 First mounting member 2 First mounting hole portion 3 slits 4 Second mounting member 5 Second mounting hole portion 6 Circular hole 7 Square hole 8 Guide section 9. Fitting recess 10 Rotation restriction part 20 Fastening structure 21 clips 22 First engaging part 23 Second engaging part 24 Grommet member 25 Main body 26 Circuit board section 27 Insertion hole 28 Peripheral wall 29 Main body flange 31 Legs 32 Tip 33 Inner protrusion 34 Arm 35 Regulating protrusion 36 Engagement protrusion 37 Pin member 38 Head 39 Slope section 40 Shaft 41 Guide protrusion 42 Positioning protrusion 43 Groove 44 Step 45 Non-locating protrusion 46 Guide groove 47 Ridge 48 Locking groove 49 Lower end 50 Pin flange

Claims

1. A fastening structure in which a first member to be attached is inserted into a first mounting hole formed in a first member to be engaged with the first member to be attached, and a second member to be attached is inserted into a second mounting hole formed in a second member to be engaged with the second member to be attached, thereby attaching the second member to the first member to be attached, facing each other; a grommet member and a pin member that are connected to each other in advance; The grommet member is a main body portion having an insertion hole formed therein and attached to the first attachment member; a plurality of leg portions extending from the periphery of the insertion hole and inserted into the first mounting hole portion; an arm portion formed on the opposite side of the body portion from the leg portion and inserted into the second mounting hole portion, the pin member has a shaft portion inserted into the insertion hole, a first engaging portion formed by the leg portion and the shaft portion is inserted into the first mounting hole portion in a non-expanded diameter state that allows insertion into the first mounting hole portion, and the shaft portion is pushed into the main body portion, causing the leg portions to expand and become in an expanded diameter state, thereby engaging the first mounting member; A fastening structure characterized by:

2. The shaft portion is a positioning protrusion that protrudes outward from the leg portion in the non-diameter-expanded state; The fastening structure according to claim 1 .

3. In the non-diameter-expanded state, the positioning protrusion is continuous from the tip end of the leg portion to the main body portion, A groove portion is formed at the end of the positioning protrusion on the side of the main body portion, the groove portion not projecting outward beyond the leg portion in the expanded diameter state.

3. The fastening structure according to claim 2.

4. The pair of arms protrude outward from the main body in directions away from each other, In a second attached member temporary holding state in which the arm portion is inserted into the second attached hole portion and positioned on the opposite side of the second attached member from the first attached member, and in the first attached member engagement state, By forward rotation about the first engagement portion as an axis, the arm portion engages with the second attachment member, thereby entering the second attachment member engagement state. The fastening structure according to any one of claims 1 to 3.

5. The arm portion is In the second workpiece temporary holding state, the second workpiece has a fitting protrusion protruding toward the second workpiece, In the second mounted member engagement state, the engagement protrusion engages with the second mounted member.

5. The fastening structure according to claim 4.

6. The pin member is a head portion and a shaft portion extending from the head portion, The head portion The shaft portion has an inclined surface portion that is inclined outwardly toward the shaft portion. The fastening structure according to any one of claims 1 to 3.

7. The first attachment member or / and the second attachment member, a rotation restricting portion that restricts the forward rotation in the second attached member engaged state, or restricts the reverse rotation opposite to the forward rotation in the second attached member temporarily held state; 5. The fastening structure according to claim 4.

8. The second attachment member is a guide portion that guides the sliding of the arm portion relative to the second workpiece during the process from the second workpiece temporary holding state to the second workpiece engagement state; 6. The fastening structure according to claim 5.

9. the guide portion is an inclined surface that rises from the edge of the second mounting hole portion along the direction of the forward rotation, 9. The fastening structure according to claim 8.

10. The guide portion is formed with a mating recess into which the mating protrusion is mated.

9. The fastening structure according to claim 8.

11. A slit into which the positioning protrusion is engaged is formed on the edge of the first mounting hole portion.

4. The fastening structure according to claim 2 or 3.

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