Fastener and mounting structure

Abstract

A grommet 12 has: a head part 20 having an insertion hole 22 into which a pin 14 is inserted; and a plurality of elastic leg parts 24 extending from the head part 20 and separated in a circumferential direction. The head part 20 has an abutment part that abuts a mounting member. The elastic leg parts 24 each have: a protruding part that protrudes inward and receives a force from the inserted pin 14 for expanding the elastic leg parts 24; a thin part 28 that is located closer to a base end side than the protruding part; a thick part 26 that is located closer to the base end side than the thin part 28 and is formed thicker in the radial direction than the thin part 28; and a step part 30 that is located between the thick part 26 and the thin part 28. The step part 30 is located in a central region among three equally divided regions from the abutment part to the protruding part in the center axis direction of the insertion hole 22.

Description

Fasteners and mounting structures

[0001] The present invention relates to a fastener that is attached to a mounting hole of a mounting member, and to a mounting structure that includes the fastener.

[0002] Patent Document 1 discloses a fastener consisting of two parts: a grommet and a pin. The grommet has a flange portion with an insertion hole and multiple expandable legs. When the fastener is inserted into a mounting hole in a panel material and the pin is pushed into the insertion hole in the grommet, the multiple legs expand and fasten to the mounting hole in the panel material.

[0003] Japanese Patent Application Laid-Open No. 2004-263811

[0004] In the technology described in Patent Document 1, the insertion force of the pin increases as the thickness of the panel material increases, while the clamping force of the leg portion may decrease as the thickness of the panel material decreases.

[0005] The object of the present invention is to provide a fastener that suppresses an increase in the insertion force of the pin when the mounting member has a thick plate thickness and suppresses a decrease in the clamping force of the leg when the mounting member has a thin plate thickness, and a mounting structure that includes the fastener.

[0006] To solve the above problems, one aspect of the present invention provides a fastener that can be fastened to a mounting hole of a mounting member, the fastener comprising a pin and a grommet into which the pin can be inserted. The grommet has a head having an insertion hole for inserting the pin, and a plurality of elastic legs extending from the head and spaced apart in the circumferential direction. The head has an abutment portion that abuts against the mounting member. The elastic legs each have a protruding portion that protrudes inward and receives a force from the inserted pin that causes the elastic legs to expand, a thin portion located proximally to the protruding portion, a thick portion located proximally to the thin portion and formed to be thicker in the radial direction than the thin portion, and a step portion located between the thick portion and the thin portion. The step portion is located in a central region of a region that divides the area from the abutment portion to the protruding portion in the central axial direction of the insertion hole into three equal parts.

[0007] Another aspect of the present invention is a mounting structure. This mounting structure includes a mounting member having a mounting hole and a fastener fastened to the mounting hole. The fastener includes a pin and a grommet into which the pin can be inserted. The grommet has a head portion having an insertion hole for inserting the pin, and a plurality of elastic legs extending from the head and spaced apart in the circumferential direction. The head portion has an abutment portion that abuts against the mounting member. The elastic legs include a protruding portion that protrudes inward and receives a force from the inserted pin that causes the elastic legs to expand, a thin-walled portion located proximally to the protruding portion, a thick-walled portion located proximally to the thin-walled portion and formed radially thicker than the thin-walled portion, and a step portion located between the thick-walled portion and the thin-walled portion. Depending on the thickness of the mounting member, the elastic legs may engage the thick-walled portion with the mounting member or the thin-walled portion with the mounting member.

[0008] According to the present invention, it is possible to provide a fastener that suppresses an increase in the insertion force of the pin when the mounting member has a thick plate thickness and suppresses a decrease in the clamping force of the leg when the mounting member has a thin plate thickness, and a mounting structure that includes the fastener.

[0009] 1A and 1B are a perspective view and an exploded view of a fastener according to an embodiment, respectively; a cross-sectional view of a fastener according to an embodiment, respectively; a cross-sectional view of a mounting structure including a fastener in a first mounting state, respectively; and a cross-sectional view of a mounting structure including a fastener in a second mounting state.

[0010] Fig. 1 is a perspective view of a fastener 10 according to an embodiment. Fig. 2 is an exploded view of the fastener 10 according to an embodiment. The fastener 10 includes a grommet 12 and a pin 14. Fig. 1 shows the state before attachment to a mounting member, with the pin 14 temporarily held in a state where it is partially inserted into the grommet 12.

[0011] The fastener 10 is inserted into a mounting member having a mounting hole and attached to the mounting member. The mounting member is composed of multiple components, such as a body panel, an exterior component, or an interior component. Exterior components include a bumper, a fender, and a cowl. For example, when the fastener 10 is used to attach a bumper to a body panel, there are some locations where the mounting member including the bumper is composed of two components and some locations where it is composed of three components. Therefore, the fastener 10 is configured to accommodate variations in the thickness of the mounting component. The fastener 10 may also be used to attach vehicle components such as decorative parts to components such as dashboards and trim panels.

[0012] The pin 14 has a shaft portion 44, a flange portion 46, an elastic portion 50, and a retaining portion 52. The shaft portion 44 is formed in a columnar shape. The flange portion 46 is formed in a disk shape and projects radially outward from the base end of the shaft portion 44.

[0013] The elastic portion 50 is formed on the outer peripheral surface of the shaft portion 44 and protrudes radially outward. The elastic portion 50 is a double-supported piece extending along the axial direction and is flexible in the radial direction. The elastic portion 50 provides a sense of operation when the pin 14 is inserted. A pair of elastic portions 50 are provided, protruding in opposite directions.

[0014] The retaining portions 52 protrude radially outward and are formed at equal intervals. The retaining portions 52 prevent the pin 14 from coming off the grommet 12. The retaining portions 52 are disposed adjacent to the elastic portion 50 in the axial direction.

[0015] The shaft portion 44 has a conical portion 48 and a receiving surface 54. The conical portion 48 is formed at the tip of the shaft portion 44. The receiving surface 54 is formed flat on the outer circumferential surface of the conical portion 48. The receiving surface 54 is located between the retaining portions 52 and is continuous with the conical portion 48 on the base end side of the conical portion 48.

[0016] The grommet 12 has a head 20 and elastic leg portions 24. The head 20 is formed in a disk shape and hooks onto the surface of the mounting member as a flange. The head 20 has an insertion hole 22 in its center. The insertion hole 22 is formed in a rectangular shape, but may also be circular. The pin 14 is inserted into the insertion hole 22. The insertion hole 22 has four corner edges that allow the elastic portion 50 and the retaining portion 52 of the pin 14 to hook onto them.

[0017] The multiple elastic legs 24 extend from the head 20, are spaced apart in the circumferential direction, and are flexible so as to expand when the pin 14 is inserted. The elastic legs 24 expand in the mounted state and engage with the rear edge of the mounting hole. Four elastic legs 24 are provided, and one hangs down from each side of the edge of the insertion hole 22.

[0018] The elastic leg portion 24 has a thick portion 26, a thin portion 28, a step portion 30, a groove portion 32, a protrusion portion 33, an enlarged diameter portion, and a protruding portion. The thick portion 26 is formed thicker than the thin portion 28 and is located closer to the base end than the thin portion 28. The thicknesses of the thick portion 26 and the thin portion 28 are measured in the radial direction. The base end of the elastic leg portion 24 is the root portion of the elastic leg portion 24, which is the portion connected to the head portion 20. The elastic leg portion 24 extends from the base end to the tip end.

[0019] The thin portion 28 is formed thinner than the thick portion 26 and is located closer to the tip than the thick portion 26. The step portion 30 is formed on the outer surface of the elastic leg portion 24 and is located between the thick portion 26 and the thin portion 28. The step portion 30 is inclined so as to recess the outer surface of the elastic leg portion 24 toward the tip.

[0020] The grooves 32 extend on the outer surface of the elastic leg portions 24 in the axial direction. This axial direction is the central axis direction of the insertion hole 22, and may be a direction along the shaft portion 44 of the pin 14. No steps are formed in the grooves 32. Forming the grooves 32 makes it easier for the elastic leg portions 24 to flex. A plurality of grooves 32 are formed spaced apart in the circumferential direction, dividing the step portion 30 in the circumferential direction. As shown in FIG. 2 , the step portion 30 includes a first step portion 30a and a second step portion 30b whose circumferential width is narrower than that of the first step portion 30a.

[0021] The first step portion 30a is formed into three parts separated by the grooves 32. The second step portion 30b is formed into two small parts sandwiched between the grooves 32. The relatively narrow second step portion 30b is formed as a protrusion, and is therefore more easily crushed than the relatively wide first step portion 30a. Therefore, when the protrusion portion 33 having the second step portion 30b is crushed, it bites into the edge of the mounting hole, making it difficult for the elastic leg portion 24 to come loose.

[0022] 3 is a cross-sectional view of the fastener 10 of the embodiment. The head 20 has an abutting portion 20a, a recess 40, and a tapered portion 42. The abutting portion 20a is located at the lower end of the outer periphery of the head 20 and abuts against the mounting member.

[0023] The recess 40 is formed in an annular shape inside the abutting portion 20a and recessed into the back surface of the head 20. The tapered portion 42 is located on the inner edge of the insertion hole 22 and is formed so as to taper downward and radially inward.

[0024] 3 shows the enlarged diameter portion 34 and the protruding portion 36 of the elastic leg portion 24. The enlarged diameter portion 34 is located on the proximal end side of the thick-walled portion 26, and causes the outer diameter of the elastic leg portion 24 to increase toward the proximal end side. The enlarged diameter portion 34 ensures the rigidity of the proximal end portion of the elastic leg portion 24.

[0025] The inner surface of the elastic leg portion 24 is uniformly formed from the tapered portion 42 to the inclined end 38 and is flat from the tapered portion 42 to the inclined end 38. Because the inner surface of the elastic leg portion 24 is flat and uniform up to the inclined end 38, the thickness of the elastic leg portion 24 changes in three stages from the base end to the inclined end 38 due to the enlarged diameter portion 34 and the stepped portion 30. The protrusion 36 is formed on the tip side of the inner surface of the elastic leg portion 24 and protrudes inward. The thin-walled portion 28 is located closer to the base end than the protrusion 36. The protrusion 36 slopes inward and toward the tip from the inclined end 38, which is one end of the thin-walled portion 28, and approaches the opposing elastic leg 24.

[0026] When the pin 14 is inserted, the protrusion 36 comes into contact with the conical portion 48 of the pin 14 and receives a force that spreads the resilient legs 24. As the pin 14 is pushed in, the resilient legs 24 spread outward and engage with the edges of the mounting hole.

[0027] When the distance from the abutment portion 20a to the pin abutment portion 36a of the protrusion 36 is divided into three equal parts in the central axial direction of the insertion hole 22, the distance is divided into a base end region 56a, a central region 56b, and a tip end region 56c. The pin abutment portion 36a of the protrusion 36 is the point of force that abuts against the pin 14 in the locked state. The abutment portion 20a is located at the base end of the elastic leg portion 24.

[0028] The step portion 30 is located in a central region 56b among the regions obtained by dividing the area from the abutting portion 20a to the protruding portion 36 into three equal parts in the direction of the central axis of the insertion hole 22. As a result, the thick portion 26 and the thin portion 28 are arranged above and below the step portion 30 provided in the central region 56b. Therefore, it is possible to set the thick portion 26 to engage when there are two mounting members, and the thin portion 28 to engage when there are three mounting members.

[0029] The step portion 30 is located closer to the tip end than the intermediate position C of the central region 56b. This shortens the length from the step portion 30 to the protruding portion 36, but because the thin-walled portion 28 is flexible from the step portion 30 to the protruding portion 36, an increase in the operating force required to insert the pin 14 can be suppressed.

[0030] In the central axial direction, a first length L1 from the abutting portion 20a to the stepped portion 30, a second length L2 from the abutting portion 20a to the inclined end portion 38, and a third length L3 from the abutting portion 20a to the pin abutting portion 36a of the protrusion 36 are set. The first length L1 is set to be greater than 50 percent of the third length L3 and less than 60 percent of the third length L3. The first length L1 is also set to be greater than 55 percent of the second length L2 and less than 70 percent of the third length L3. This allows the axial position of the stepped portion 30 to be set, thereby appropriately determining the boundary between the thick-walled portion 26 and the thin-walled portion 28.

[0031] 4 is a cross-sectional view of a mounting structure including fastener 10 in a first mounting state. In the first mounting state, fastener 10 is mounted to a first mounting member 60 and a second mounting member 62. The mounting members and fastener 10 are collectively referred to as the mounting structure. After fastener 10 is inserted into first mounting hole 60a of first mounting member 60 and second mounting hole 62a of second mounting member 62, pin 14 is pushed deep into insertion hole 22 to mount fastener 10.

[0032] In the first mounting state, the flange portion 46 of the pin 14 is inserted until it abuts against the surface of the head 20, and the protrusions 36 of the elastic legs 24 abut against the receiving surfaces 54 of the pin 14, expanding the elastic legs 24. When the elastic legs 24 expand, the thick portions 26 bend with the back edges of the first mounting holes 60a as the point of application and engage with the back edges of the first mounting holes 60a. Here, it is desirable that the insertion force when pushing the pin 14 is reduced and that the clamping force, which indicates the force with which the elastic legs 24 clamp the mounting member, is high.

[0033] When the thick portion 26 is engaged, the clamping force can be ensured because the thick portion 26 is less likely to bend than the thin portion 28. Furthermore, the length of the elastic leg portion 24 from the protrusion 36 to the engagement position of the thick portion 26 is sufficient, so the thickness of the thick portion 26 prevents the insertion force of the pin 14 from becoming too high.

[0034] 5 is a cross-sectional view of the mounting structure including the fastener 10 in the second mounting state. In the second mounting state, the fastener 10 is mounted to the first mounting member 60, the second mounting member 62, and the third mounting member 64. After the fastener 10 is inserted into the first mounting hole 60a, the second mounting hole 62a, and the third mounting hole 64a of the third mounting member 64, the pin 14 is pushed deep into the insertion hole 22 to mount the fastener.

[0035] When the protrusion 36 of the elastic leg portion 24 contacts the receiving surface 54 of the pin 14 and the elastic leg portion 24 expands, the thin-walled portion 28 bends with the back edge of the third mounting hole 64a as the point of action and engages with the back edge of the third mounting hole 64a.

[0036] When the thin-walled portion 28 is locked, the length of the elastic leg 24 from the protrusion 36 to the locking position of the thin-walled portion 28 is short, but the thin-walled portion 28 is more flexible than the thick-walled portion 26, so an increase in insertion force can be suppressed. Also, because the length of the elastic leg 24 from the protrusion 36 to the locking position of the thin-walled portion 28 is short, the angle of expansion increases, increasing the amount of penetration into the edge of the third mounting hole 64a, making it less likely to come off and suppressing a decrease in clamping force.

[0037] When there is no need to distinguish between the first mounting member 60, the second mounting member 62, and the third mounting member 64, they are simply referred to as mounting members. In other words, the mounting member may be made up of two or three pieces.

[0038] 4 and 5, depending on the thickness of the mounting member, the elastic leg portion 24 may engage the mounting member with the thick portion 26 or the thin portion 28. When the mounting member is made up of two sheets, the thick portion 26 engages, and when the mounting member is made up of one more sheet, the thin portion 28 engages. This prevents the insertion force of the fastener 10 from becoming too high or the clamping force from becoming too low, depending on the thickness of the mounting member.

[0039] The present invention is not limited to the above-described embodiments, and various modifications such as design changes may be made to the embodiments based on the knowledge of those skilled in the art, and such modified embodiments may also be included within the scope of the present invention.

[0040] In the embodiment, the fastener 10 is attached to a mounting member made up of multiple sheets, but this is not limiting. For example, the fastener 10 may be attached to a single mounting member to close a mounting hole in the mounting member.

[0041] The present invention relates to a fastener that is attached to a mounting hole of a mounting member, and to a mounting structure that includes the fastener.

[0042] 10 fastener, 12 grommet, 14 pin, 20 head, 20a abutment portion, 22 insertion hole, 24 elastic leg portion, 26 thick portion, 28 thin portion, 30 step portion, 30a first step portion, 30b second step portion, 32 groove portion, 33 protrusion portion, 34 enlarged diameter portion, 36 protrusion portion, 38 inclined end portion, 40 recessed portion, 42 tapered portion, 44 shaft portion, 46 flange portion, 48 conical portion, 50 elastic portion, 52 retaining portion, 54 receiving surface, 56a base end region, 56b central region, 56c tip end region, 60 first mounting member, 60a first mounting hole, 62 second mounting member, 62a Second mounting hole, 64 third mounting member, 64a third mounting hole.

Claims

1. A fastener to be fastened to a mounting hole of a mounting member, comprising: a pin; and a grommet into which the pin can be inserted, wherein the grommet has: a head having an insertion hole into which the pin is inserted; and a plurality of elastic legs extending from the head and spaced apart in the circumferential direction, wherein the head has an abutment portion that abuts against the mounting member, and the elastic legs have: a protruding portion that protrudes inward and receives a force from the inserted pin that causes the elastic legs to expand, a thin-walled portion located closer to the base end than the protruding portion, a thick-walled portion located closer to the base end than the thin-walled portion and formed thicker in the radial direction than the thin-walled portion, and a step portion located between the thick-walled portion and the thin-walled portion, wherein the step portion is located in the central region of a region obtained by dividing the area from the abutment portion to the protruding portion in the direction of the central axis of the insertion hole into three equal parts.

2. The fastener according to claim 1, wherein the step portion is located closer to the tip end than the intermediate position of the central region.

3. A fastener as described in claim 1 or 2, characterized in that the elastic leg portion has a groove formed on its outer surface and extending in the direction of the central axis, and the step portion is formed on the outer surface of the elastic leg portion and is divided in the circumferential direction by the groove portion.

4. The fastener according to claim 3, characterized in that the divided step portions include a first step portion and a second step portion having a circumferential width narrower than that of the first step portion.

5. A mounting structure comprising: a mounting member having a mounting hole; and a fastener fastened to the mounting hole, wherein the fastener comprises: a pin; and a grommet into which the pin can be inserted, wherein the grommet has: a head having an insertion hole into which the pin is inserted; and a plurality of elastic legs extending from the head and spaced apart in the circumferential direction, wherein the head has an abutment portion that abuts against the mounting member, wherein the elastic legs have: a protruding portion that protrudes inward and receives a force from the inserted pin that causes the elastic legs to expand, a thin-walled portion located closer to the base end than the protruding portion, a thick-walled portion located closer to the base end than the thin-walled portion and formed thicker in the radial direction than the thin-walled portion, and a step portion located between the thick-walled portion and the thin-walled portion, wherein the elastic legs have a configuration in which the thick-walled portion engages with the mounting member in some cases and a configuration in which the thin-walled portion engages with the mounting member in other cases depending on the thickness of the mounting member.

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