Grommet

Abstract

To secure a holding force on a peripheral edge of a through-hole while suppressing an increase in weight.SOLUTION: A grommet includes: an annular fitting body 10; a first cylindrical body 20 through which a wiring material We is inserted in one space; a second cylindrical body 30 to be expanded by the wiring material in another space; a first partition wall 41 with an outer peripheral edge thereof being coupled to the fitting body and an inner peripheral edge being coupled to the first cylindrical body; a second partition wall 42 with an outer peripheral edge thereof being coupled to the fitting body; a third partition wall 43 with an inner peripheral edge thereof being coupled to the second cylindrical body; a fourth partition wall 44 that is projects toward the first partition wall side from the outer peripheral edge of the third partition wall, and of which end part is positioned on a radially inner side of the inner peripheral edge of the second partition wall; a coupling wall 45 coupling the inner peripheral edge of the second partition wall with the end part of the fourth partition wall; a plurality of outer engagement elements 51 which bulge from an outer wall surface of the second partition wall around an axis and are arranged opposite each other at a gap on a radially outer side of an outer wall surface of the fourth partition wall; and engaged elements 52 that bulge in correspondence with the respective outer engagement elements from the inner wall surfaces of the third and fourth partition walls on the radially inner side of the outer engagement elements.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a grommet. [Background technology]

[0002] Conventionally, when wiring materials such as electric wires are passed through a through hole between two spaces, a grommet is sometimes installed to protect the wiring materials from the periphery of the through hole. The grommet is sometimes made liquid-proof to prevent liquids such as water from passing between the two spaces. This grommet has a circular, doughnut-shaped main body that fits around the periphery of the through hole, a cylindrical body that is arranged coaxially with the main body and whose inner periphery is in close contact with the outer periphery of the wiring material, and an annular connector that connects the inner periphery of the main body to one end of the cylindrical body. For example, this type of grommet is disclosed in Patent Document 1 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-85748 Summary of the Invention [Problem to be solved by the invention]

[0004] The main body of this conventional grommet has multiple segments divided circumferentially, and each segment is connected to the cylindrical body via a connector. In this grommet, when the cylindrical body receives a force in the cylindrical axial direction from the wiring material, the connector bends, deforming the multiple segments of the main body, and engaging each segment with the outer circumferential surface of the cylindrical body, thereby preventing further deformation of the main body. In addition, in this grommet, when the cylindrical body receives a force in the cylindrical axial direction from the wiring material, the connector bends, deforming the multiple segments of the main body, and engaging each segment with adjacent segments in the circumferential direction, thereby preventing further deformation of the main body. Regardless of the form of the conventional grommet, by preventing further deformation of the main body, a decrease in the holding force of the main body against the periphery of the through hole is suppressed, and the main body does not detach from the periphery of the through hole. However, with conventional grommets, as the diameter of the main body increases, the size of each segment must also increase to prevent deformation of the main body when the cylindrical body receives force in the axial direction from the wiring material. For this reason, the weight of conventional grommets increases significantly as the diameter of the main body increases.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a grommet that can ensure a holding force against the peripheral edge of a through hole while suppressing an increase in weight. [Means for solving the problem]

[0006] The present invention provides a ring-shaped fitting body that is disposed in a circular through-hole through which a wiring material passes between two spaces, and that has a ring-shaped fitting groove formed on the periphery of the through-hole to be fitted from the inner diameter side; a first cylindrical body that is formed in a cylindrical shape with a smaller diameter than the fitting body, that is disposed coaxially with the axis of the fitting body in one of the spaces, and that allows the wiring material to be inserted into the cylinder; a second cylindrical body that is formed in a cylindrical shape with a smaller diameter than the fitting body, that is disposed coaxially with the axis in the other space, and that is expanded by the wiring material inserted into the cylinder; a first partition wall that is formed in a circular donut shape coaxially with the axis, that has its outer peripheral edge connected to the fitting body in one of the spaces, and its inner peripheral edge connected to one end of the first cylindrical body; The present invention is characterized by comprising a second partition connected to the fitting body, a third partition formed in a circular donut shape coaxially with the axis and having its inner peripheral edge connected to one end of the second cylindrical body in the other space, a fourth partition having an annular shape that protrudes from the outer peripheral edge of the third partition toward the first partition and has an annular end on the first partition side positioned radially inward from the inner peripheral edge of the second partition, a connecting wall that connects the inner peripheral edge of the second partition and the end of the fourth partition, multiple external locking bodies that bulge from the outer wall surface of the second partition at equal intervals around the axis and are positioned opposite the outer wall surface of the fourth partition with a gap radially outward, and a locked body that bulges from the inner wall surfaces of the third partition and the fourth partition for each external locking body, radially inward from the external locking bodies. [Effects of the Invention]

[0007] In the grommet according to the present invention, when the second cylindrical body receives a force from the wiring material toward the first cylindrical body, each combination of the external locking body and the locked body is locked, preventing further collapse from the outer periphery of the second bulkhead. This prevents deformation of the fitting body and the fitting groove, ensuring a holding force against the periphery of the through hole. Furthermore, in the grommet according to the present invention, while increasing the diameter of the fitting body inevitably requires larger external locking bodies and multiple locked bodies, this does not require a body as large as conventional divided bodies, thereby minimizing weight increases. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a grommet according to an embodiment. [Figure 2] FIG. 2 is a plan view of the grommet as viewed in the axial direction. [Figure 3] FIG. 3 is a plan view of the grommet as viewed in a direction perpendicular to the axial direction. [Figure 4] FIG. 4 is a cross-sectional view taken along line X1-X1 in FIG. [Figure 5] 5 is a cross-sectional view taken along line X2-X2 in FIG. [Figure 6] FIG. 6 is a diagram showing a deformation state when a load is applied, which corresponds to the cross section taken along line X1-X1 in FIG. [Figure 7] FIG. 7 is a diagram showing a deformation state when a load is applied, which corresponds to the cross section taken along line X2-X2 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a grommet according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0010] [Embodiment] One embodiment of a grommet according to the present invention will be described with reference to FIGS.

[0011] Reference numeral 1 in Figures 1 to 7 indicates a grommet of this embodiment. This grommet 1 is disposed in a circular through-hole (hereinafter referred to as "routing material insertion hole") Pw1 through which the wiring material We passes between two spaces, and protects the wiring material We from a peripheral portion Pw2 of the wiring material insertion hole Pw1 in the wall Pw between the two spaces, while also preventing liquids such as water from passing between the two spaces through a gap between the peripheral portion Pw2 and the wiring material We (Figures 1 to 7). Therefore, this grommet 1 is molded from an elastic material such as an elastomer.

[0012] Here, the wiring material We is, for example, a single cylindrical electric wire (such as a communication wire or a power supply wire) or a cylindrical bundle of multiple electric wires. When this wiring material We includes multiple electric wires, the multiple electric wires are bundled together using an exterior part such as a corrugated tube or a resin tape. Here, the assembled state of the grommet 1 and the wiring material We is referred to as a wire harness WH (FIGS. 1 to 7).

[0013] Furthermore, the wall Pw between the two spaces may be, for example, a plate-like member such as a panel of a vehicle body, or may be the wall of a storage box such as an electrical junction box. Here, a cylindrical wiring material We is inserted into a circular wiring material insertion hole Pw1 of the wall Pw, and a circular gap between the wiring material We and a circular peripheral edge Pw2 of the wiring material insertion hole Pw1 is closed with a grommet 1.

[0014] This grommet 1 has an annular fitting body 10 that fits into the peripheral edge Pw2 of the wiring material insertion hole Pw1 (FIGS. 1 to 7). This fitting body 10 is provided with an annular fitting groove 11 that fits into the peripheral edge Pw2 of the wiring material insertion hole Pw1 from the inner diameter side (FIGS. 1 and 3 to 7). This fitting body 10 is arranged concentrically with the wiring material insertion hole Pw1 and protrudes into one space side and the other space side. This fitting body 10 is formed with the fitting groove 11 that is concentric with the peripheral edge Pw2 of the wiring material insertion hole Pw1.

[0015] The grommet 1 also has a first cylindrical body 20 formed in a cylindrical shape with a smaller diameter than the fitting body 10, arranged coaxially with the axis of the fitting body 10 in one space, and through which the wiring material We is inserted (FIGS. 1 and 3 to 7). The first cylindrical body 20 shown here is arranged at a position separated from the fitting body 10 in the axial direction of the fitting body 10. The first cylindrical body 20 has a smaller diameter than the fitting body 10 and is formed in a cylindrical shape with an inner diameter larger than the outer diameter of the wiring material We. The first cylindrical body 20 has a bellows portion 21 that is expandable and contractible in the cylindrical axis direction (FIGS. 1 and 3 to 7).

[0016] In the following, when the term "axis" is used without any special reference, the term refers to the axis of the fitting 10 and its extension, as well as the axis of the hole axis of the wiring material insertion hole Pw1 and its extension.

[0017] The grommet 1 also has a second cylindrical body 30 (FIGS. 1 to 7) that is formed in a cylindrical shape with a smaller diameter than the fitting body 10, is arranged coaxially with the axis in the other space, and is expanded by the wiring material We inserted into the cylinder. The second cylindrical body 30 shown here is arranged at a position separated from the fitting body 10 in the axial direction of the fitting body 10. The second cylindrical body 30 is formed in a cylindrical shape with a smaller diameter than the fitting body 10 and an inner diameter that is smaller than the outer diameter of the wiring material We. Therefore, when the wiring material We is inserted into the second cylindrical body 30, the second cylindrical body 30 receives a radially outward force from the wiring material We over the entire circumference of its inner circumferential surface, and is expanded radially outward.

[0018] The grommet 1 has a first partition 41 formed in a circular doughnut shape coaxially with the axis, with its outer peripheral edge connected to the fitting 10 in one space and its inner peripheral edge connected to one end of the first cylindrical body 20 ( FIGS. 3 to 7 ). The inner peripheral edge of the first partition 41 is connected to one end of the first cylindrical body 20 on the fitting 10 side, and the first cylindrical body 20 protrudes outward from this inner peripheral edge to separate it from the fitting 10. The first partition 41 shown here is formed as a plate-like wall like the side wall of a truncated cone, with the annular outer peripheral edge on the lower base side connected to the fitting 10 and the annular inner peripheral edge on the upper base side connected to one end of the first cylindrical body 20 ( FIGS. 3 to 7 ).

[0019] Additionally, this grommet 1 has a second partition 42 formed in a circular doughnut shape coaxial with the axis, with its outer periphery connected to the fitting body 10 in the other space (FIGS. 1 to 7). The second partition 42 shown here is formed as a plate-like wall like the side wall of a truncated cone, with the annular outer periphery on the lower base connected to the fitting body 10 and the annular inner periphery on the upper base positioned further away from the fitting body 10 in the axial direction than the outer periphery (FIGS. 4 and 5).

[0020] The grommet 1 also has a third partition 43 formed in a circular doughnut shape coaxially with the axis, and whose inner peripheral edge is connected to one end of the second cylindrical body 30 in the other space ( FIGS. 1 to 7 ). The inner peripheral edge of the third partition 43 is connected to one end of the second cylindrical body 30 on the fitting 10 side, and the second cylindrical body 30 protrudes outward from this inner peripheral edge to separate it from the fitting 10. The third partition 43 shown here is formed as a plate-like wall like the side wall of a truncated cone, and its annular inner peripheral edge on the upper base is connected to one end of the second cylindrical body 30, and its annular outer peripheral edge on the lower base is located closer to the fitting 10 in the axial direction than the inner peripheral edge and farther from the fitting 10 than the annular inner peripheral edge on the upper base of the second partition 42 ( FIGS. 4 and 5 ).

[0021] The grommet 1 also has an annular fourth partition wall 44 that protrudes from the outer peripheral edge of the third partition wall 43 toward the first partition wall 41, and whose annular end on the first partition wall 41 side is located radially inward of the inner peripheral edge of the second partition wall 42 ( FIGS. 1 and 4 to 7 ). The fourth partition wall 44 shown here is formed as an annular wall that protrudes in the axial direction from the outer peripheral edge of the third partition wall 43 toward the first partition wall 41 side. The fourth partition wall 44 protrudes in the axial direction closer to the first partition wall 41 than the inner peripheral edge of the second partition wall 42 and closer to the third partition wall 43 than the outer peripheral edge of the second partition wall 42, and whose annular end on the first partition wall 41 side in the protruding direction is located radially inward of the gap between the inner and outer peripheral edges of the second partition wall 42 ( FIGS. 4 and 5 ).

[0022] The grommet 1 also has an annular connecting wall 45 that connects the inner peripheral edge of the second partition wall 42 and the end of the fourth partition wall 44 on the first partition wall 41 side (FIGS. 4 to 7). The connecting wall 45 shown here has a concentric annular first connecting wall portion 45a that protrudes radially inward from the inner peripheral edge of the second partition wall 42, and an annular second connecting wall portion 45b that connects the inner peripheral edge of the first connecting wall portion 45a to the end of the fourth partition wall 44 on the first partition wall 41 side. The first connecting wall portion 45a is formed as a plate-like wall having a plane perpendicular to the axis. The second connecting wall portion 45b is formed as a plate-shaped wall like the side wall of a truncated cone, and its annular outer peripheral edge portion on the lower base side is connected to the inner peripheral edge portion of the first connecting wall portion 45a, and its annular inner peripheral edge portion on the upper base side is connected to the end of the fourth partition 44 on the first partition 41 side.

[0023] This grommet 1 has a hollow grommet body formed inside by its fitting body 10, first partition wall 41, second partition wall 42, third partition wall 43, fourth partition wall 44, and connecting wall 45, and the first cylindrical body 20 and second cylindrical body 30 protrude from this grommet body.

[0024] This grommet 1 has multiple external locking bodies 51 that bulge outward at equal intervals around the axis from the outer wall surface of the second partition 42 and are arranged facing the outer wall surface of the fourth partition 44 with a gap therebetween on the radially outer side (FIGS. 1 to 7). This grommet 1 also has locked bodies 52 that bulge outward from the inner wall surfaces of the third partition 43 and the fourth partition 44 for each external locking body 51, radially inward of the external locking bodies 51 (FIGS. 4 to 7).

[0025] The external locking body 51 and the locked body 52 are each formed as a polyhedron that will dent if a localized overload is applied, but will maintain its external shape if a tensile load or surface pressure is applied that is not large enough to cause fracture. The external locking bodies 51 are arranged at equal intervals around the axis, with a small gap between adjacent ones around the axis. The locked bodies 52 are arranged directly below and radially inward of the external locking body 51, with the fourth partition wall 44 interposed therebetween. Therefore, the locked bodies 52 are arranged at equal intervals around the axis, with a gap between adjacent ones around the axis.

[0026] In this grommet 1, when the wiring material We is pulled on the first cylindrical body 20 side, the second cylindrical body 30 receives a force from the wiring material We toward the first cylindrical body 20 side and is pulled toward the first cylindrical body 20 side (FIGS. 4 to 7). Then, in this grommet 1, when the second cylindrical body 30 is pulled toward the first cylindrical body 20 side, the third partition wall 43 and the fourth partition wall 44 are pushed by the second cylindrical body 30 and move toward the first partition wall 41 side (FIGS. 4 to 7). In this grommet 1, the external locking body 51 and the locked body 52 are formed as polyhedrons with the rigidity described above, so when the third partition 43 and the fourth partition 44 move toward the first partition 41, the overall deflection of the second partition 42, the third partition 43 and the fourth partition 44 is suppressed, while the outer peripheral edge of the second partition 42, the inner peripheral edge of the third partition 43 and the connecting wall 45 each deflect (Figures 4 to 7).

[0027] As the outer peripheral edge of the second partition 42 bends, the inner peripheral edge of the second partition 42 tilts starting from the outer peripheral edge so that it approaches the first partition 41 (FIGS. 4 to 7). The external locking body 51 tilts in the same manner as the second partition 42 tilts. Meanwhile, the third partition 43 and the fourth partition 44 move toward the first partition 41, while as the outer peripheral edge of the second partition 42 bends, the inner peripheral edge of the third partition 43 tilts in the same manner as the second partition 42 tilts (FIGS. 4 to 7). The locked body 52 tilts in the same manner as the third partition 43 and the fourth partition 44 tilt. Therefore, when the second cylindrical body 30 receives a force from the wiring material We toward the first cylindrical body 20, the outer peripheral edge of the second partition wall 42, the inner peripheral edge of the third partition wall 43, and the connecting wall 45 each deflect (FIGS. 6 and 7). Therefore, in order to maintain the locked state, the locked body 52 is formed into a shape (for example, a polyhedron having the rigidity described above) that is unable to deform when a reaction force is received from the external locking body 51 via the fourth partition wall 44 in the locked state. The external locking body 51 is also formed into a shape (for example, a polyhedron having the rigidity described above) that is unable to deform when a force is applied to the locked body 52 via the fourth partition wall 44 in the locked state.

[0028] In this way, in the grommet 1 of this embodiment, when the second cylindrical body 30 receives a force from the wiring material We toward the first cylindrical body 20, the external locking body 51 and the locked body 52 are locked together for each combination, preventing further collapse from the outer peripheral edge side of the second partition wall 42. As a result, in this grommet 1, deformation of the fitting body 10 is suppressed, and deformation of the fitting groove 11 is suppressed, so that the holding force of the wiring material insertion hole Pw1 against the peripheral edge Pw2 can be ensured.

[0029] Furthermore, in conventional grommets, for example, when the second cylindrical body receives a force from the wiring material toward the first cylindrical body, multiple external locking bodies (such as the aforementioned divided bodies) are locked onto the outer circumferential surface of the second cylindrical body to prevent deformation of the fitting groove. Therefore, in conventional grommets, if the diameter of the fitting body is increased, the multiple external locking bodies must also be increased in size, which inevitably increases the weight. However, in the grommet 1 of this embodiment, although the multiple external locking bodies 51 and the multiple locked bodies 52 must be increased in size, they do not require a size as large as the conventional external locking bodies, and therefore the weight increase can be suppressed compared to conventional grommets.

[0030] Incidentally, this grommet 1 has an internal locking body 53 that bulges out from the inner wall surface of the second partition 42 on the back side of each external locking body 51, and is positioned opposite the annular inner peripheral surface 10a, which is radially inward of the groove bottom of the fitting groove 11 in the fitting body 10, with a gap therebetween (Figures 4 to 7).

[0031] The internal locking body 53 is formed as a polyhedron that will dent if a localized overload is applied, but will maintain its external shape if a tensile load or surface pressure is applied that is not large enough to cause fracture. The internal locking body 53 protrudes from the inner wall surface of the second partition wall 42 on the back side of the external locking body 51 to a position just below the inner circumferential surface 10a of the fitting body 10, radially inward, and is disposed with a gap from the inner circumferential surface 10a (FIGS. 4 and 5). Therefore, the internal locking bodies 53 are disposed at equal intervals around the axis, with a gap between adjacent ones around the axis.

[0032] The internal locking body 53, in cooperation with the external locking body 51, suppresses the overall deflection of the second partition wall 42. The internal locking body 53 tilts together with the external locking body 51 in conjunction with the collapse of the second partition wall 42 as shown above (FIGS. 4 to 7). The internal locking body 53 locks onto the inner peripheral surface 10a of the fitting body 10 in accordance with the deflection of the outer peripheral edge of the second partition wall 42, the inner peripheral edge of the third partition wall 43, and the connecting wall 45 when the second cylindrical body 30 receives a force from the wiring material We toward the first cylindrical body 20 (FIGS. 6 and 7). As a result, in this grommet 1, when the second cylindrical body 30 receives a force toward the first cylindrical body 20 from the wiring material We, each combination of the external locking body 51 and the locked body 52 enters a locked state, and all internal locking bodies 53 enter a locked state with the inner circumferential surface 10a of the fitting body 10, further preventing further collapse from the outer circumferential edge side of the second partition wall 42. Furthermore, in this grommet 1, all internal locking bodies 53 apply a radially outward force to the inner circumferential surface 10a of the fitting body 10, and this force acts from the groove bottom of the fitting groove 11 to the periphery Pw2 of the wiring material insertion hole Pw1. Therefore, in this grommet 1, the radially outward force can be used as a holding force for the periphery Pw2 of the wiring material insertion hole Pw1.

[0033] As described above, the grommet 1 of this embodiment can ensure a holding force for the peripheral edge portion Pw2 of the wiring material insertion hole Pw1 while suppressing an increase in weight. [Explanation of symbols]

[0034] 1 grommet 10. Fitting body 10a Inner surface 11 Fitting groove 20 First cylinder 30 Second cylinder 41 1st bulkhead 42 Second bulkhead 43 Third bulkhead 44 4th bulkhead 45 Connecting wall 51 External locking body 52 Locked object 53 Internal locking body Pw1 Cable insertion hole (through hole) Pw2 Periphery We wiring material

Claims

1. a circular fitting body disposed in a circular through hole through which a wiring material passes between two spaces, and having a circular fitting groove provided on a periphery of the through hole to be fitted from an inner diameter side; a first cylindrical body formed in a cylindrical shape with a diameter smaller than that of the fitting body, arranged coaxially with the axis of the fitting body in one of the spaces, and through which the wiring material is inserted; a second cylindrical body formed in a cylindrical shape having a smaller diameter than the fitting body, arranged coaxially with the axis in the other space, and expanded by the wiring material inserted into the cylinder; a first partition wall formed in a circular donut shape coaxially with the axis, the outer peripheral edge of which is connected to the fitting body in the one space, and the inner peripheral edge of which is connected to one end of the first cylindrical body; a second partition wall formed in a circular doughnut shape coaxial with the axis, the outer periphery of which is connected to the fitting body in the other space; a third partition wall formed in a circular doughnut shape coaxial with the axis line, and having an inner peripheral edge portion connected to one end of the second cylindrical body in the other space; an annular fourth partition wall that protrudes from an outer peripheral edge portion of the third partition wall toward the first partition wall and has an annular end portion on the first partition wall side that is located radially inward of an inner peripheral edge portion of the second partition wall; an annular connecting wall that connects the inner peripheral edge portion of the second partition wall and the end portion of the fourth partition wall; a plurality of external engaging bodies that bulge out from an outer wall surface of the second partition wall at equal intervals around the axis and are disposed to face an outer wall surface of the fourth partition wall with a gap therebetween on the radially outward side; a retained body that bulges out from an inner wall surface of each of the third partition wall and the fourth partition wall at a position radially inward of the external retaining body for each of the external retaining bodies; A grommet comprising:

2. A grommet as described in claim 1, characterized in that the engaging body engages the external engaging body through the fourth partition wall in response to the deflection of the outer peripheral edge of the second partition wall, the inner peripheral edge of the third partition wall, and the connecting wall when the second cylindrical body receives a force from the routing material toward the first cylindrical body.

3. The interlocking body interlocks with the external interlocking body via the fourth partition wall in response to the deflection of the outer peripheral edge of the second partition wall, the inner peripheral edge of the third partition wall, and the connecting wall when the second cylindrical body receives a force from the wiring material toward the first cylindrical body, and is formed into a shape that cannot be deformed when receiving a reaction force from the external interlocking body via the fourth partition wall in this interlocking state, 2. The grommet according to claim 1, wherein the external engaging body is formed in a shape that is unable to deform when a force is applied to the engaged body via the fourth partition wall in the engaged state.

4. 4. A grommet as described in claim 1, 2 or 3, characterized in that it has an internal retaining body that bulges out from the inner wall surface of the second partition wall on the back side of each external retaining body, and is positioned opposite to and with a gap radially inward from the annular inner peripheral surface of the mating body that is radially inward from the groove bottom of the mating groove.

5. The grommet described in claim 4, characterized in that the internal retaining body is engaged with the inner peripheral surface radially inward of the bottom of the mating groove in the mating body in response to the deflection of the outer peripheral edge of the second partition wall, the inner peripheral edge of the third partition wall, and the connecting wall when the second cylindrical body receives a force from the wiring material toward the first cylindrical body.

Images