JP2001251724A - Waterproofing structure for electric connection box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waterproofing structure for an electric junction box capable of preventing water. SOLUTION: A wire harness, not shown in Fig., is mounted on an electric equipment mounting block 14 and a lower cover 13 is coupled to the bottom of the block 14. A packing 18 is provided on the bottom end of the block 14, and a cutout 22 for drawing out the wire harness is formed in the sidewall 13b of the lower cover 13. A grommet 24 is fit in the cutout 22. A packing holder rib 27, which is provided protrusively on the fitting part 25 of the grommet 24, is press contacted onto the packing 18. The wire harness is passed though the grommet 24. This structure prevents the infiltration of water into the electric junction box 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof structure for an electric junction box.

[0002]

2. Description of the Related Art Conventionally, various electric connection boxes such as a junction box, a relay box, a fusible link box, and an electric control unit used for an electric circuit of an automobile have been proposed.

[0003] As shown in FIGS.
Is composed of a case body 42, an upper cover 43, and a lower cover 44. Electrical components (not shown) are attached inside the case body 42. Case body 4
A wire harness (not shown) is connected to the bottom surface of 2. A lower cover 44 having an upper opening is coupled to a lower portion of the case body 42. A notch 4 is formed on the side wall of the lower cover 44 for drawing out the wire harness to the outside.
5 are formed. The base end of a rubber grommet 46 is fitted into the notch 45. A wire harness (not shown) is inserted through the grommet 46. With the above configuration, the intrusion of water into the electric connection box 41 is prevented to some extent.

[0004]

However, since the waterproof structure of the conventional electric junction box 41 is simple as described above, a gap is formed between the grommet 46 and the case body 42 and between the grommet 46 and the lower cover 44. Easy,
Water was easy to enter from there. Further, when a force is applied in the direction of arrow F1 shown in FIG.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide a waterproof structure of an electric junction box which can surely prevent water from entering. Further, a second object is to provide a waterproof structure of the electric junction box which can prevent the grommet from coming off.

[0006]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a case main body in which electric components are mounted and a wire harness is connected to a bottom surface, and the case main body is provided. A lower cover having an upper opening to which a lower portion can be connected, a packing provided at a lower end of the case main body, and a cutout for drawing out the wire harness to the outside at a side wall of the lower cover, In a waterproof structure of an electric junction box in which a base end of a grommet for inserting the wire harness into a cutout portion is provided, a packing holding rib is protruded from an upper side of an outer peripheral surface of the base end of the grommet, and the packing is provided. The gist is that the holding rib is pressed against the packing.

In the invention described in claim 2, a plurality of projections are provided on the outer peripheral surface at the base end of the grommet, and an engaged portion for engaging the projections with the notch is provided. That is the gist.

According to the third aspect of the present invention, the packing is accommodated in a packing accommodating groove provided at a lower end portion of the case body, and the packing holding rib is disposed in the packing accommodating groove. And

The "action" of the present invention will be described below. According to the first aspect of the invention, the packing holding rib protruding from the grommet is pressed against the packing provided at the lower end of the case body. Therefore, a gap is less likely to be generated between the grommet, the case body, and the lower cover. Therefore, it is possible to prevent water from entering the electric connection box through the gap.

According to the second aspect of the present invention, the plurality of projections projecting from the grommet engage with the engaged portions provided in the cutouts. Therefore, even if water attempts to enter through the space between the projection and the engaged portion, the water is blocked by the projection. Therefore, it is possible to more reliably prevent water from entering the electric connection box through the gap. In addition, when a force is applied to the grommet in a direction in which the wire harness is pulled out, the protrusion is caught on the engaged portion. As a result, the movement of the grommet is stopped. Therefore, it is possible to prevent the grommet from falling out of the electric connection box.

According to the third aspect of the invention, when a force is applied to the grommet in a direction in which the wire harness is pulled out to the outside, not only the projection is caught on the engaged portion but also the packing holding rib is provided in the packing housing. It gets caught on the side wall of the groove. Therefore, it is possible to reliably prevent the grommet from falling out of the electric connection box.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a waterproof structure of an electric junction box in which the present invention is embodied in an electric junction box for a vehicle will be described in detail with reference to FIGS.

As shown in FIGS. 1 and 2, the electric junction box 1
1 is configured by covering an upper cover 12 and a lower cover 13 on an electrical component mounting block 14 as a case body. The electrical component mounting block 14 has a substantially rectangular parallelepiped shape. Inside the electrical component mounting block 14,
Electrical components (not shown) are mounted. A plurality of flange portions 15 are provided at an upper portion on the outer surface of the electrical component mounting block 14. As shown in FIG. 2, the lower surface of the upper cover 12 is in contact with the upper surface of the flange portion 15. As shown in FIG. 1, a plurality of locking projections 16 are provided at the lower end of the outer surface of the electrical component mounting block 14. A plurality of electric wires (not shown) are connected to the lower surface of the electrical component mounting block 14. These electric wires are combined into one by a tape to form a wire harness.

An outer wall 17a and an inner wall 17b are provided on the periphery of the lower end portion of the electrical component mounting block 14 so as to project downward. The gap between the outer wall 17a and the inner wall 17b forms a packing accommodation groove 17. Packing receiving groove 17
Is the same as the height of the inner wall 17b. Exterior wall 1
The protrusion amount of 7a is larger than the protrusion amount of the inner wall 17b. The lower ends of the outer wall 17a and the inner wall 17b are tapered. A rubber packing 18 is housed in the packing housing groove 17. The packing 18 is inserted to the deepest part in the packing accommodation groove 17. Packing 1
8 is formed by making a belt-like rubber material into an annular shape. Therefore, a seam is formed in the packing 18.

The lower cover 13 is attached to a lower side of the electrical component mounting block 14. The lower cover 13 has an upper opening. At the upper end of the outer surface of the lower cover 13, a U-shaped locked portion 19 is arranged so as to correspond to the locking projection 16. The side wall 13a of the lower cover 13 has a bent portion 2 that is bent inward.
0 is provided. At the same time, a plurality of ribs 21 are formed at equal intervals on the inner wall surface of the side wall 13a of the lower cover 13 so as to extend substantially in the vertical direction. Rib 21
Are formed in a rectangular shape along the inner wall surface of the side wall 13a.

The side wall 13b of the lower cover 13
Notch 2 for pulling out the wire harness to the outside
2 are formed. The cutout portion 22 is formed in a U-shape. A U-shaped projecting portion 23 is provided at a peripheral portion of the notch 22. An engagement groove 23a as an engaged portion is provided on the inner peripheral surface of the protrusion 23.

A grommet 24 made of rubber is fitted in the notch 22. The grommet 24 is formed using a rubber material harder than the packing 18. The grommet 24 protrudes outward from the side wall 13b of the lower cover 13. The wire harness is inserted through the grommet 24. The grommet 24 has a cylindrical shape. The grommet 24 is the engaging portion 2 as a base end.
5 and the cylindrical portion 26 are integrally formed. Engagement part 25
Consists of an outer portion 25a and an inner portion 25b. The cylindrical portion 26 protrudes from the outer portion 25a in a direction in which the wire harness is pulled out. A plurality of bellows 26a are provided in the cylindrical portion 26.
Is provided. The presence of these bellows 26a allows the tubular portion 26 to be bent. Tube part 2
The tip of 6 is cut off at the top. When the grommet 24 is fitted to the lower cover 13, the height of the upper end surface of the engagement portion 25 of the grommet 24 matches the height of the upper edge of the lower cover 13.

As shown in FIG. 3, a packing holding rib 2 is provided on the upper side of the outer peripheral surface of the engaging portion 25 of the grommet 24.
7 protrudes from the outer portion 25a and the inner portion 25b. The packing holding rib 27 is
And are formed integrally. As shown in FIG. 1, the packing holding rib 27 is formed as long as possible. The packing holding rib 27 is formed linearly along the direction in which the packing housing groove 17 extends. The length of the packing holding rib 27 is smaller than the width of the outer portion 25a and the inner portion 25b. In the present embodiment, the length of the packing holding rib 27 is set to 20 to 30 mm. Also,
The height of the packing holding rib 27 is 5 to 10 mm. As shown in FIG. 3, the packing holding rib 27 is disposed in the packing accommodating groove 17. The plate thickness of the packing holding rib 27 is smaller than the width of the packing housing groove 17. A slight play is provided between the side wall surface of the packing accommodation groove 17 and the side surface of the packing holding rib 27. The packing holding rib 27 is pressed against the lower surface of the packing 18. The upper end of the packing holding rib 27 is flat. In addition, three projections 28 are provided below the outer peripheral surface of the engaging portion 25 of the grommet 24. These projections 28
It is arranged so as to correspond to a.

Next, a method of manufacturing the electric connection box 11 will be described in detail. First, the plurality of protrusions 28 protruding from the grommet 24 are engaged with the engagement grooves 23 a provided on the protrusion 23. Further, the packing 18 is inserted into the packing receiving groove 17 of the electrical component mounting block 14. At the same time, the wire harness is inserted through the grommet 24. Next, the packing holding rib 27 protruding from the grommet 24 is
It is housed in a packing housing groove 17 provided at the lower end of the electrical component mounting block 14 and is brought into pressure contact with the packing 18. At the same time, the locking projection 16 and the locked portion 19 are fitted. As a result, the lower cover 13 is connected to the lower side of the electrical component mounting block 14.

In this state, since the packing 18 is made of rubber, a reaction force is applied to the deformed packing 18 so as to return to the original shape. Therefore, a gap is less likely to be generated between the grommet 24 and the electrical component mounting block 14. Therefore, it is difficult for water to enter through the gap. The projections 28 are provided at a plurality of locations. Therefore, even if water attempts to enter through the space between the protrusion 28 and the engaging groove 23a, the water is blocked by the protrusion 28.

Next, the wire harness is pulled out from the grommet 24. In this case, a force is applied to the grommet 24 in a direction in which the wire harness is drawn out. Therefore, even if the grommet 24 attempts to move outward of the lower cover 13, the projection 28 is caught on the inner surface of the engagement groove 23a. At the same time, the packing holding rib 27 is hooked on the outer wall 17a of the packing receiving groove 17. As a result, the movement of the grommet 24 is stopped.

Thereafter, the electrical connection box 11 is constructed by covering the upper part of the electrical component mounting block 14 with the upper cover 12. Therefore, according to the present embodiment, the following effects can be obtained.

(1) The packing holding rib 27 protruding from the grommet 24 is pressed against the packing 18 provided at the lower end of the electrical component mounting block 14. The force by which the packing holding rib 27 presses the packing 18 and the packing 1
The grommet 24, the electrical component mounting block 14, and the lower cover 13 are brought into close contact with each other by the reaction force of the grommet 8 to return to its original shape. Therefore, the electric connection box 11 is inserted through this gap.
Water can be prevented from entering the inside.

(2) The plurality of projections 28 projecting from the grommet 24 engage with the engagement grooves 23a provided in the notch 22. Therefore, even if water attempts to enter through the space between the protrusion 28 and the engaging groove 23a, the water is blocked by the protrusion 28. Therefore, it is possible to more reliably prevent water from entering the electric connection box 11 through the gap. Further, when a force is applied to the grommet 24 in a direction in which the wire harness is pulled out, the projection 28 is caught in the engagement groove 23a. As a result, the movement of the grommet 24 is stopped. Therefore, it is possible to prevent the grommet 24 from falling out of the electric connection box 11.

(3) A force is applied to the grommet 24 in the direction in which the wire harness is pulled out. In this case, the projection 28 on the lower side of the grommet 24 is
a as well as the packing holding rib 27 on the upper side of the grommet 24
7 is hooked on the outer wall 17a. As a result, grommet 2
The movement of 4 is stopped. Therefore, it is possible to prevent the grommet 24 from dropping out of the electric connection box 11 at the upper and lower two places, and it is possible to reliably prevent the grommet 24 from falling out of the electric connection box 11.

(4) On the side wall 13a of the lower cover 13,
A bent portion 20 that bends inward is provided. At the same time, a plurality of ribs 21 are provided on the inner wall surface of the side wall 13a of the lower cover 13 so as to extend substantially in the vertical direction. Therefore, even when an external force acts on the lower cover 13, the deformation of the lower cover 13 can be prevented.

(5) The packing 18 is provided on the electrical component mounting block 14 side. Therefore, it is not necessary to form the packing 18 into a complicated shape according to the shape of the notch 22. Therefore, the shape of the packing 18 can be simplified. Therefore, the manufacturing cost of the packing 18 can be reduced.

The embodiment of the present invention may be modified as follows. In the above embodiment, the protrusion 28 is provided so as to protrude only on the lower side of the engaging portion 25 of the grommet 24. However, as shown in FIG. 4, the protrusion 28 may be provided on the upper side of the engaging portion 25 of the grommet 24, and the protrusion 28 may be in contact with the inner wall 17 b of the packing housing groove 17. With this configuration, when the grommet 24 moves in the direction in which the wire harness is pulled out from the electric connection box 11,
The projection 28 is hooked not only on the side wall of the engagement groove 23a but also on the inner wall 17b of the packing accommodation groove 17. As a result, the movement of the grommet 24 is stopped. Therefore, grommet 24
Can be more reliably prevented from dropping out of the electrical junction box 11.

In the embodiment, the lower edge of the electrical component mounting block 14 is in contact with the upper surface of the engaging portion 25 of the grommet 24. However, as shown in FIG. 5, a groove 31 may be provided on the upper surface of the engagement portion 25, and the lower edge of the electrical component mounting block 14 may be inserted into the groove 31. With this configuration, when the grommet 24 moves in the direction in which the wire harness is pulled out of the electric connection box 11, the lower edge of the electrical component mounting block 14 is hooked on the side wall of the groove 31. As a result, the movement of the grommet 24 is stopped.
Therefore, it is possible to more reliably prevent the grommet 24 from falling off from the electric connection box 11.

In the above embodiment, the side wall 13a of the lower cover 13 is provided with the bent portion 20 which is bent inward. However, the bent portion 20 may be bent outward.

In the above embodiment, a plurality of projections 28 are provided on the outer peripheral surface of the engagement portion 25 of the grommet 24, and the notch 22 has an engagement groove 23a for engaging the projection 28. Was provided. However, the protrusion 28 may be provided only at one position in the engaging portion 25 of the grommet 24.

In the above embodiment, the packing 18 is formed by making a belt-like rubber material into an annular shape. However, when the packing 18 is formed, the annular packing 18 may be formed.

In the above embodiment, the packing 18 is housed in the packing housing groove 17. However, the packing 18 may be provided on the lower end surface of at least one of the outer wall 17a and the inner wall 17b. Further, the packing 18 may be provided on the lower end surface of the electrical component mounting block 14 without providing the outer wall 17a and the inner wall 17b.

In the above embodiment, the upper end of the packing holding rib 27 is flat. However, the upper end of the packing holding rib 27 may be pointed. With this configuration, the packing holding rib 27 is more reliably pressed against the lower surface of the packing 18. Therefore, it is possible to more reliably prevent the grommet 24 from coming off the electric connection box 11.

Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments will be listed below together with their effects. (1) The electric connection box according to (1) to (3), wherein a bent portion which bends inwardly is provided on a side wall of the lower cover, and a rib is provided on the inner wall surface of the lower cover so as to extend substantially in a vertical direction. Waterproof structure. Therefore, according to the technical idea (1), the deformation of the lower cover can be prevented.

(2) An engaging portion in which a packing holding rib is arranged so as to correspond to the lower end of the case body, and a plurality of projections are arranged so as to correspond to the notch formed in the lower end and the lower cover. A grommet comprising a bellows portion that can be bent freely, and a wire harness is inserted through the grommet.

[0037]

As described in detail above, according to the first aspect of the present invention, it is possible to prevent water from entering the electric connection box through the gap.

According to the second aspect of the present invention, it is possible to more reliably prevent water from entering the electric connection box through the gap. Further, it is possible to prevent the grommet from falling out of the electric connection box.

According to the third aspect of the present invention, it is possible to reliably prevent the grommet from falling out of the electric connection box.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an electric junction box according to an embodiment.

FIG. 2 is an overall sectional view of the electric junction box.

FIG. 3 is a sectional view of a main part of the electric connection box.

FIG. 4 is a sectional view of a main part of an electric junction box in another example.

FIG. 5 is a cross-sectional view of a main part of an electric junction box in another example.

FIG. 6 is an exploded perspective view of an electric junction box according to the related art.

FIG. 7 is an overall sectional view of the electric junction box.

FIG. 8 is a sectional view of a main part of the electric connection box.

[Explanation of symbols]

11 ... electric junction box, 13 ... lower cover, 13b ... side wall,
14 ... Electrical component mounting block as case body, 17 ...
Packing receiving groove, 18: packing, 22: notch, 23
a: engagement groove as engaged portion, 24: grommet, 25
... engaging portion as a base end portion, 27 ... packing press rib,
28 ... Projection.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05K 5/06 H05K 5/06 D 7/00 7/00 MF term (reference) 4E352 AA09 BB10 CC32 GG04 4E360 AB33 BA02 BC06 BC07 BD03 CA02 EA03 EA24 EA29 EC05 ED12 FA14 GA29 GB94 5G361 AA06 AB09 AC02 AC04 AC09 AC13 AE01 5G363 AA01 BA02 CA06 CA15 CB08

Claims (3)

[Claims] 1. A case body in which electric components are attached and a wire harness is connected to a bottom surface, and a lower cover having an upper opening to which a lower portion of the case body can be coupled, wherein a lower end of the case body is provided. In addition to providing packing in the portion, a cutout portion for drawing the wire harness to the outside is formed on the side wall of the lower cover, and a base end of a grommet for inserting the wire harness into the cutout portion is fitted. In the waterproof structure of a connection box, a packing holding rib is projected from an upper side of an outer peripheral surface at a base end of the grommet, and the packing holding rib is pressed against the packing. . 2. A plurality of projections protruding from an outer peripheral surface of a base end portion of the grommet, and an engaged portion for engaging the projections with the notch portion is provided. 2. The waterproof structure of the electrical junction box according to 1. 3. The packing according to claim 1, wherein said packing is housed in a packing housing groove provided at a lower end portion of said case body, and said packing holding rib is arranged in said packing housing groove. Item 3. A waterproof structure for an electrical junction box according to Item 2.