JP3963801B2 - Seal structure of grommet for electrical junction box - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealing structure for a grommet for an electrical connection box, for example, in which a grommet is fitted into an opening for inserting a wire harness formed in an electrical connection box for an automobile, and waterproof is sealed between the electrical connection box and the grommet.
[0002]
[Prior art]
Electrical junction boxes that mount electrical components such as fuses, relays, and wiring harness connectors in the engine room of automobiles are usually waterproof so that raindrops do not contaminate electrical components or cause failures. It has a seal structure.
For example, the electrical connection box 1 shown in FIG. 7 has a storage space for fitting a plurality of connection connectors with a substantially box-shaped box body 2 and a waterproof cover 3 that covers the upper opening of the box body 2 so as to be openable and closable. Is forming.
[0003]
The front ends of the peripheral wall portions 2a and 3a of the box body 2 and the waterproof cover 3 are equipped with matching portions 2b and 3b that abut against the front ends of the other peripheral wall portions. By making the contact portion a seal structure, water is prevented from entering the housing space (see FIG. 9).
[0004]
As shown in FIG. 9, the seal structure is provided with a packing 6 as a seal member fitted in the recessed groove 4 formed in the mating portion 3 b of the waterproof cover 3, while the mating portion 32 of the box body 2 is As the projection row 8 that is in pressure contact with the packing 6, predetermined waterproofing is achieved by the pressure contact between the projection row 8 and the packing 6.
[0005]
Further, the peripheral wall 2a of the box body 2 has a U-shaped opening 5 for inserting the wire harness for leading out the wire harness W which is a long member connected to the connector in the housing space. The opening 5 is formed so as to prevent water or the like from entering the inside of the electrical connection box 1 by fitting a grommet 7 extrapolated to the wire harness W.
[0006]
As shown in FIG. 8, the grommet 7 is formed by fitting an outer 11 made of a soft material such as a synthetic rubber formed in a cylindrical shape on the outer periphery of an inner 9 made of a hard material such as a hard plastic formed in an annular shape. This is a grommet for an electrical junction box that is configured to insert the flange portion 11 a of the outer 11 into the opening 5.
[0007]
A grommet holding groove 5a having a concave cross section is formed on the inner peripheral edge of the opening 5 by a pair of clamping walls 10 and 10, and a flange portion 11a is inserted into the grommet holding groove 5a from above the opening 5. Then, the outer peripheral edge 14 of the flange portion 11a excluding the projection row 15 formed on the upper end surface is fitted and sandwiched in the plate thickness direction, so that the gap between the opening 5 and the grommet 7 is sealed.
And the packing 6 of the said waterproof cover 3 is press-contacted to the protrusion row | line | column 8 of the said surrounding wall part 2a and the protrusion row | line | column 15 of the said flange part 11a which became the substantially the same surface, The box main body 2 and the said waterproof cover 3 of FIG. The contact portion between the mating portions 2b and 3b is waterproof-sealed.
[0008]
[Problems to be solved by the invention]
By the way, the waterproof seal structure between the opening 5 of the box body 2 and the flange 11a of the grommet 7 is formed by the grommet holding groove 5a formed on the inner periphery of the opening 5 as described above. The outer peripheral edge 14 is sandwiched in the thickness direction so as to be sealed in a watertight manner.
[0009]
However, the pair of sandwiching walls 10, 10 forming the grommet holding groove 5 a extends to the upper edge of the peripheral wall portion 2 a where the projection row 8 that must be pressed against the packing 6 fitted in the concave groove 4 is formed. Cannot be extended, and the outer peripheral edge 14 of the portion where the projection row 15 of the grommet 7 is formed cannot be fitted in the plate thickness direction.
[0010]
Therefore, if a gap is generated at the boundary portion (between the contact surfaces facing each other) between the projection row 8 and the projection row 15 that cannot be fitted into the grommet holding groove 5a, there is a possibility that water resistance may be reduced and water may enter. is there.
For example, the boundary portion has a planar shape extending in the vertical direction, and its upper end becomes a transverse line in the thickness direction of the peripheral wall portion 2a and is exposed on the upper end surface of the peripheral wall portion 2a. When the cover 3 is closed, the projection row 15 is brought into pressure contact with the packing 6 and is deformed or displaced by the pressing force of the packing 6, so that a gap is easily generated at the boundary portion.
[0011]
Further, when the grommet 7 is fitted into the opening 5 of the box body 2, if the projection row 15 is deformed or displaced due to excessive pressing force by the operator, a step or gap is formed between the projection row 8. It tends to occur.
Accordingly, an object of the present invention is to solve the above-mentioned problems, and to prevent the occurrence of a gap between the grommet fitted into the opening formed in the peripheral wall portion of the box body and the opening. It is an object of the present invention to provide a grommet sealing structure for an electrical junction box that can be made.
[0012]
[Means for Solving the Problems]
The above-mentioned object of the present invention is a sealing structure for a grommet for an electrical junction box that is fitted into an opening for inserting a wire harness formed in a peripheral wall portion of a box body,
A seal member is fitted and installed in the recessed groove formed in the peripheral wall portion of the waterproof cover, and a protrusion row formed on the peripheral wall portion of the box body is pressed against the seal member to align the box main body and the waterproof cover. The part is sealed,
On the inner peripheral edge of the opening is formed a grommet holding groove having a concave cross section that fits with the flange portion of the grommet sandwiched in the plate thickness direction,
The inner peripheral surface of the opening is immersed and engaged in an engagement groove formed in the outer peripheral surface of the flange portion facing the inner peripheral surface, and an edge on the mating portion side is the engagement portion. An engaging rib that contacts the inner surface of the groove is suspended ,
On both sides of the upper edge of the flange portion of the grommet in which the protrusion row that press-contacts the seal member is formed, an extension portion is provided to cover the protrusion row formed on the peripheral wall portion of the adjacent box body. This is achieved by the sealing structure of the grommet for an electrical junction box.
[0013]
According to the above configuration, when the grommet for the electrical junction box is fitted into the opening of the box body, the grommet holding groove is fitted with the flange portion sandwiched in the plate thickness direction, and is suspended from the inner peripheral surface of the opening. Since the engaged rib is inserted into an engagement groove recessed in the outer peripheral surface of the flange portion of the grommet, and the edge on the mating portion side contacts the inner surface of the engagement groove. There is no gap between the inner peripheral surface and the flange portion outer peripheral surface.
In addition, the engagement rib and the engagement groove are a boundary portion between the projection row formed on the peripheral wall portion of the box body and the projection row formed on the upper edge of the flange portion of the grommet (opposing contact). It is also possible to provide a gap at the boundary portion that cannot be fitted into the grommet holding groove.
[0014]
Further, since the engagement rib is immersed and fitted in the engagement groove, and the end edge on the mating portion side contacts the inner surface of the engagement groove, the rigidity of the flange portion of the grommet is increased, and the flange portion The protrusion row formed on the upper edge is less likely to be deformed or misaligned due to the pressing force of the sealing member to be brought into pressure contact or the operator's excessive pressing force when fitting.
Therefore, the waterproofness of the electrical connection box grommet fitted into the opening is improved.
[0015]
Further, on both sides of the upper edge of the flange portion of the grommet in which the projection row that press-contacts the seal member is formed, an extension portion is provided to cover the projection row formed on the peripheral wall portion of the adjacent box body . The extension portion covers a boundary portion between the projection row formed on the peripheral wall portion of the box body and the projection row formed on the upper end edge of the flange portion of the grommet, so that the extension portion is fitted to the opening portion. A gap is less likely to occur between the grommet for the electrical junction box and the waterproofness is further improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a sealing structure of an electrical connection box grommet according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. A reference example will be described before the description of the embodiment.
FIG. 1 is an enlarged perspective view of a main part for explaining a sealing structure of a grommet for an electrical junction box according to a reference example of the present invention, and FIG. 2 is an exploded perspective view of an electrical junction box having the seal structure shown in FIG. FIG. 3 is an enlarged perspective view of a main part showing a fitted state of the grommet for an electrical junction box shown in FIG.
[0017]
The electrical junction box 21 according to the reference example shown in FIG. 2 has substantially the same configuration as the electrical junction box 1 shown in FIG. 7, and can open and close a substantially box-shaped box body 23 and an upper opening of the box body 23. A housing space 26 for fitting a plurality of connection connectors is formed with a waterproof cover 25 that covers the cover.
[0018]
At the tips of the peripheral wall portions 23a and 25a of the box body 23 and the waterproof cover 25, there are provided matching portions 23b and 25b that abut against the tips of the other peripheral wall portions. By making the contact portion a seal structure, water is prevented from entering the housing space 26 (see FIG. 1).
[0019]
As shown in FIGS. 1 and 2, the sealing structure is provided with a packing 29 as a sealing member fitted in a concave groove 27 formed in the mating portion 25 b of the waterproof cover 25, while the mating portion of the box body 23. Reference numeral 23 b denotes a projection row 49 that press-contacts the packing 29, and a predetermined waterproofing is achieved by press-contact between the projection row 49 and the packing 29. The packing 29 is formed by annularly forming a string-like soft elastic body having a rectangular cross-sectional shape.
[0020]
Further, the peripheral wall portion 23a of the box body 23 is notched in a U-shape with a wire harness insertion opening 35 for leading out a wire harness which is a long member connected in the housing space 26 with a connector. The opening 35 is formed, and by fitting a grommet 41 for an electrical connection box (hereinafter referred to as a grommet) extrapolated to the wire harness, water or the like can be prevented from entering the inside of the electrical connection box 21. It is illustrated.
[0021]
The grommet 41 is configured by fitting an outer 43 made of a soft material such as a synthetic rubber formed in a cylindrical shape on the outer periphery of an inner (not shown) made of a hard material such as a hard plastic formed in an annular shape. This is a grommet for an electrical junction box in which the flange 43a of the outer 43 is inserted into the opening 35. At the upper edge of the flange portion 43a, a protrusion row 51 is formed which is continuous with the protrusion row 49 of the box body 23.
[0022]
A grommet holding groove 35a having a concave cross section is formed on the inner peripheral edge of the opening 35 by a pair of clamping walls 50, 50, and the inner peripheral surface of the opening 35 is opposed to the inner peripheral surface. The fitting groove 55 is recessed and fitted in an engagement groove 55 provided in the outer peripheral surface 57 of the flange portion 43a, and an end edge (upper edge in FIG. 1) 53a is formed on the inner surface 55a of the engagement groove 55. An engaging rib 53 that abuts is suspended.
That is, the engagement groove 55 does not penetrate the upper end edge (the upper surface of the projection row 51) of the flange portion 43a but opens downward. On the other hand, the engaging rib 53 has an end edge (upper end edge) 53a on the mating portion side positioned slightly lower than the upper end surface (upper surface of the projection row 49) of the peripheral wall portion 23a.
[0023]
Therefore, as shown in FIG. 1, the grommet 41 according to the present reference example is inserted into the end edge 53 a of the engagement rib 53 with the lower opening of the engagement groove 55, and moves below the opening 35 in this state. As a result, the engaging rib 53 is inserted and fitted into the engaging groove 55, and the outer peripheral edge of the flange portion 43a is fitted in the plate thickness direction by the grommet holding groove 35a. Thus, there is no gap between the inner peripheral surface of the opening 35 and the outer peripheral surface 57 of the flange portion 43a.
[0024]
In addition, the engagement rib 53 and the engagement groove 55 include a protrusion row 49 formed on the peripheral wall portion 23a of the box body 23, and a protrusion row 51 formed on the upper edge of the flange portion 43a of the grommet 41. Can also be provided at the boundary portion (between the abutting surfaces facing each other), and a gap at the boundary portion that cannot be fitted into the grommet holding groove 35a can be hardly generated.
[0025]
Further, since the engaging rib 53 is inserted and fitted into the engaging groove 55 and the end edge 53a on the mating portion side contacts the inner surface 55a of the engaging groove 55, the flange portion 43a of the grommet 41 is provided. The rigidity is increased, and the protrusion row 51 formed on the upper end edge of the flange portion 43a is less likely to be deformed by the pressing force of the packing 29 to be pressed.
[0026]
In addition, when the grommet 41 is fitted into the opening 35, an end edge 53 a that is the upper end of the engagement rib 53 that is inserted into the engagement groove 55 is an inner surface that is the upper inner surface of the engagement groove 55. Since it abuts on 55a and becomes a stopper when the grommet is inserted, the grommet 41 can be fitted in an appropriate position and posture, and deformation and displacement can be prevented.
Therefore, the waterproofness of the electrical connection box grommet 41 fitted into the opening 35 is improved.
[0027]
FIG. 4 is an enlarged perspective view of a main part for explaining the sealing structure of the grommet for an electrical junction box according to the embodiment of the present invention, and FIG. 5 is an exploded perspective view of the electrical junction box having the seal structure shown in FIG. FIG. 6 is an enlarged perspective view of a main part showing a fitted state of the grommet for an electrical junction box shown in FIG. In addition, the same code | symbol is attached | subjected to the member same as the member shown to the said reference example , and the overlapping description shall be abbreviate | omitted.
[0028]
As shown in FIGS. 4 and 5, the seal structure according to the present embodiment is adjacent to both sides of the upper edge of the flange portion 43 a of the grommet 42 in which the protruding row 51 is formed in pressure contact with the packing 29 of the waterproof cover 25. An extension portion 65 is provided to cover the projection row 49 formed on the peripheral wall portion 23a of the box body 23.
[0029]
As shown in FIG. 4, ribs 61 are formed by notching both sides of the projection row 49 on the upper end surface of each peripheral wall 23 a adjacent to both sides across the opening 35.
On the other hand, a groove 67 that fits with the rib 61 is formed on the lower surface of the extension 65 provided in the grommet 42.
And the extension part 65 is made to fit the upper end surface of each peripheral wall part 23a, as shown in FIG.
At this time, since the extension portion 65 is thinned by providing the recess portion 67, the extension portion 65 in which the recess portion 67 is fitted to the rib 61 is connected to the upper end surface of each peripheral wall portion 23a. Only a slight level difference is generated between them, and this level difference can be absorbed by the elastic deformation of the packing 29.
[0030]
That is, in the grommet 42 according to the present embodiment , as shown in FIG. 6, the extension portion 65 is formed on the protrusion row 49 formed on the peripheral wall portion 23 a of the box body 23 and the upper end edge of the flange portion 43 a. Since it covers the boundary portion with the formed projection row 51, a gap is less likely to be formed between the opening 35 and the grommet 42 to be fitted, and the waterproofness is further improved.
[0031]
The configuration of the box body, waterproof cover, seal member, projection row, opening, grommet, grommet holding groove, engagement groove, engagement rib, and the like according to the sealing structure of the grommet for an electrical junction box of the present invention is as described above. is not limited to the form of construction, it is needless to say that can take various forms based on the gist of the present invention.
[0032]
【The invention's effect】
As described above in detail, according to the grommet sealing structure for an electric junction box of the present invention, when the grommet for an electric junction box is fitted into the opening of the box body, the grommet holding groove causes the flange portion to extend in the plate thickness direction. The engaging ribs suspended on the inner peripheral surface of the opening are inserted into the engaging grooves recessed in the outer peripheral surface of the flange portion of the grommet, and the end on the mating portion side Since the edge abuts against the inner surface of the engagement groove, there is no gap between the inner peripheral surface of the opening and the outer peripheral surface of the flange portion.
[0033]
Further, the engagement rib and the engagement groove may be provided at a boundary portion between the projection row formed on the peripheral wall portion of the box body and the projection row formed at the upper end edge of the flange portion of the grommet. In addition, it is possible to make it difficult to generate a gap at the boundary portion that cannot be fitted into the grommet holding groove.
[0034]
Further, since the engagement rib is immersed and fitted in the engagement groove, and the end edge on the mating portion side contacts the inner surface of the engagement groove, the rigidity of the flange portion of the grommet is increased, and the flange portion The protrusion row formed on the upper edge is less likely to be deformed or misaligned due to the pressing force of the sealing member to be brought into pressure contact or the operator's excessive pressing force when fitting.
Therefore, the waterproofness of the electrical connection box grommet fitted into the opening is improved.
Further, on both sides of the upper edge of the flange portion of the grommet in which the projection row that press-contacts the seal member is formed, an extension portion is provided to cover the projection row formed on the peripheral wall portion of the adjacent box body. The extension portion covers a boundary portion between the projection row formed on the peripheral wall portion of the box body and the projection row formed on the upper end edge of the flange portion of the grommet, so that the extension portion is fitted to the opening portion. A gap is less likely to occur between the grommet for the electrical junction box and the waterproofness is further improved.
[Brief description of the drawings]
FIG. 1 is an enlarged perspective view of a main part for explaining a sealing structure of a grommet for an electrical junction box according to a reference example of the present invention.
2 is an exploded perspective view of an electrical junction box having the seal structure shown in FIG. 1. FIG.
3 is an enlarged perspective view of a main part showing a fitting state of the grommet for an electrical junction box shown in FIG. 1. FIG.
FIG. 4 is an enlarged perspective view of a main part for explaining the sealing structure of the grommet for an electrical junction box according to the embodiment of the present invention.
FIG. 5 is an exploded perspective view of an electrical junction box having the seal structure shown in FIG.
6 is an enlarged perspective view of a main part showing a fitting state of the electrical connection box grommet shown in FIG. 4;
FIG. 7 is an external perspective view of an electrical junction box having a conventional grommet sealing structure for an electrical junction box.
8 is an overall perspective view of the electrical connection box grommet shown in FIG. 7;
9 is an enlarged perspective view of a main part for explaining a sealing structure of the grommet for an electrical junction box shown in FIG.
[Explanation of symbols]
21 electrical connection box 23 box main body 23a peripheral wall 25 waterproof cover 25a peripheral wall 27 concave groove 29 packing (seal member)
35 Opening 35a Grommet holding groove 41 Grommet (Grommet for electrical connection box)
43a Flange portion 49 Projection row 51 Projection row 53 Engagement rib 53a End edge 55 Engagement groove 55a Inner surface

Claims (1)

It is a sealing structure of a grommet for an electrical junction box that is fitted into an opening for inserting a wire harness formed in a notch in a peripheral wall portion of the box body,
A seal member is fitted and installed in the recessed groove formed in the peripheral wall portion of the waterproof cover, and a protrusion row formed on the peripheral wall portion of the box body is pressed against the seal member to align the box main body and the waterproof cover. The part is sealed,
On the inner peripheral edge of the opening is formed a grommet holding groove having a concave cross section that fits with the flange portion of the grommet sandwiched in the plate thickness direction,
The inner peripheral surface of the opening is immersed and engaged in an engagement groove formed in the outer peripheral surface of the flange portion facing the inner peripheral surface, and an edge on the mating portion side is the engagement portion. An engaging rib that contacts the inner surface of the groove is suspended ,
On both sides of the upper edge of the flange portion of the grommet in which the protrusion row that press-contacts the seal member is formed, an extension portion is provided to cover the protrusion row formed on the peripheral wall portion of the adjacent box body. Grommet seal structure for electrical junction box.

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