JP4490784B2 - Waterproof grommet mounting structure and electrical junction box equipped with the same - Google Patents

Description

  The present invention relates to a waterproof grommet mounting structure in which a waterproof grommet for inserting an electric wire is fitted into an opening of a box to prevent water from entering the opening from the outside, and an electrical junction box including the same. .

  FIG. 11 to FIG. 12 show one form of a conventional waterproof grommet mounting structure and an electrical junction box having the same (see Patent Document 1).

  A waterproof grommet (hereinafter referred to as a grommet) 61 is formed of an elastic rubber material, has a bellows portion 62 and a base end side flange portion 63, a wire harness 64 is inserted therein, and the flange portion 63 is an electric junction box. The wire harness 64 is led out from the inside of the electrical connection box J by being fitted into the opening 67 of the J lower cover 65, and the grommet 61 prevents water, dust, and the like from entering the opening from the outside.

  The opening 67 of the lower cover 65 is opened in a substantially U shape, and has a groove 68 for fitting the flange 63 of the grommet 61 on the inner periphery. The upper end surface 69 of the flange portion 63 is formed flat and has a rib 70 in the width direction, and a horizontal flange portion 71 that is in close contact with the upper end surface 69 of the flange portion 63 protrudes from the upper cover 66 of the electrical junction box J. A groove for fitting the packing 72 is formed in the flange 71, and the rib 70 presses against the packing 72 to prevent intrusion of water or the like from the upper end surface side of the flange 63.

  A hard and substantially cylindrical inner member 73 made of a synthetic resin is fitted inside the grommet 61, and supports the elastic grommet 61 so as to be in close contact with the lower cover 65 and the upper cover 66. The inner member 73 is locked to the lower cover 65 by a locking claw 74, and the grommet 61 is prevented from being lifted.

  The upper end surface 69 of the flange 63 of the grommet 61 and the rib 70 are projected in a mountain shape, or the upper end surface 75 of the inner member 73 is formed in a mountain shape so that the upper end surface 69 of the flange 63 of the grommet 61 is a mountain shape. Patent Document 1 discloses a structure in which the waterproofness of the upper cover 66 is increased by expanding the cover.

The electric junction box J is composed of a synthetic resin lower cover 65, an upper cover 66, and a wiring board, a bus bar circuit, an electric component such as a fuse and a relay, and the like mounted in the lower cover. The lower cover 65 and the upper cover 66 constitute a box. A plurality of electric wires constituting the wire harness 64 are connected to these wiring boards, circuits, electrical components and the like.
Japanese Utility Model Publication No. 4-85525 (FIGS. 8 and 10)

  However, in the conventional waterproof grommet mounting structure and the electrical junction box including the same, the upper cover 66 and the upper end surface 69 of the flange 63 of the grommet 61 are brought into close contact with each other. 66 or the flange 63 of the grommet 61 may cause a risk that water may enter due to a decrease in adhesion, or the upper cover 66 and the grommet 61 may have a risk of high-pressure cleaning in the engine room of an automobile. There was a concern that water would enter from the upper end surface 69 of the collar portion 63.

  In the above embodiment, the upper end surface 69 of the flange 63 of the grommet 61 is brought into close contact with the upper cover 66. However, for example, the grommet 61 is turned upside down and used to fit the flange of the grommet to the upper cover. If the lower cover of the grommet collar is in close contact with the lower cover, or the opening is continuously provided in both the lower cover and the upper cover, the end face of the grommet collar is in close contact with the lower cover or the upper cover. In some cases, the above problems can occur as well.

  In view of the above-described points, the present invention provides a waterproof grommet mounting structure capable of enhancing the waterproof property between the end of the grommet attached to the box and the cover of the box, and an electric junction box including the same. The purpose is to do.

To achieve the above object, the mounting structure of the waterproof grommet according to claim 1 of the present invention, an opening is provided in the lower cover, elastic waterproof grommet for wire insertion is fitted in the opening, the is upper cover is joined to constitute the box body to the lower cover, located the ends of the waterproof grommet grommet fitting portion of the upper cover, an inner member of hard is fitted inside the said end, the the grommet fitting portion, the extension rib entering deeply downward than the flat surface is protruded toward narrower longitudinal than the flat surface while pressing down the flat surface of the rear end of the upper end surface of the end portion The front end surface intersecting the upper end surface of the end portion contacts the front end surface of the grommet fitting portion, the rib of the inner member contacts the rear end surface of the end portion, and the grommet is adjacent to the extension rib. Waterproof packing is provided in the groove of the fitting part, The upper end surface of the end portion adjacent the long rib, provided ribs entering the waterproof the packing, at the same time the extension rib bites down into the flat surface of the end portion, the rib upper end faces It is characterized by entering upward into the waterproof packing.

  With the above configuration, the grommet is fitted into the opening of one cover, and the other cover is joined to one cover. At the same time, the extension rib of the other cover presses the grommet, and the tip of the extension rib is strong against the grommet. In close contact. Thereby, waterproofness increases.

Also, when the other cover is joined to one cover and the extension rib of the other cover presses the grommet, the grommet is fitted in the grommet fitting part of the other cover, so the grommet is fitted to the grommet It is compressed in the part and closely adheres to the inner wall surface of the grommet fitting part. This further increases waterproofness.

Also, when the other cover is joined to one cover and the extension rib of the other cover presses the grommet, the grommet presses the direction of the extension rib and the direction orthogonal to the press, that is, the front end face of the grommet, the grommet fitting part The front end surface of the grommet, that is, the portion where water enters from the outside into the box body is in close contact with the front end surface of the grommet fitting portion, thereby improving the waterproof property.

Also, when the other cover is joined to one cover and the extension rib of the other cover presses the grommet, the grommet is compressed between the hard inner member and the extension rib is bent and deformed in the pressing direction of the grommet. Is kept small, and the extension rib and the grommet adhere more strongly. In addition, the pressing rib is pushed in the direction orthogonal to the front, that is, the front end surface of the grommet is brought into contact with the front end surface of the grommet fitting portion, and the front end surface of the grommet, that is, the portion where water enters from the outside into the box body It adheres more strongly to the front end face of the grommet fitting part. These increase the waterproofness.

In addition, when the other cover is joined to one cover and the extension rib of the other cover presses the grommet, the rib of the inner member is positioned close to the extension rib, and the rib receives the compressive force of the grommet. Since the grommet compression reaction force causes the front end surface of the grommet, that is, the portion on the side where water enters from the outside into the box body, to be brought into strong contact with the front end surface of the grommet fitting portion, waterproofness is enhanced.

Further, when the other cover is joined to one cover and the extension rib of the other cover presses the grommet, the grommet portion adjacent to the extension rib rises in the direction opposite to the pressing and strongly adheres to the waterproof packing. Thereby, the waterproofness by waterproof packing improves.

An electrical junction box according to claim 2 is provided with the waterproof grommet mounting structure according to claim 1 .

With the above-described configuration, an electrical junction box having the effects of the invention of claim 1 is provided. In the electrical junction box, multiple wires are introduced into the box (inside the junction box body) through the cover through the grommet. For example, electrical components such as relays, fuses and fusible links in the box, circuit boards and bus bars Connected to a circuit or the like. According to the configuration of the first aspect, the electrical components and circuits in the box are reliably waterproofed, and the reliability of the electrical connection is ensured for a long period of time.

  According to the first aspect of the present invention, the extension rib of the other cover presses the grommet, and the tip of the extension rib is in close contact with the grommet, so that the other cover that is the conventional weakness, that is, the cover for mounting the grommet. The waterproof property between the cover on the opposite side and the end of the grommet is improved.For example, there is no need to worry about high-pressure washing in the engine room or splashing water while the vehicle is running. Safely protected from rust and poor electrical contact.

Further, when the extension rib of the other cover presses the grommet, the grommet is compressed in the grommet fitting portion and tightly adheres to the inner wall surface of the grommet fitting portion, thereby improving the waterproofness.

In addition, the grommet is compressed in the direction perpendicular to the pressure by the extension ribs, and the front end surface of the grommet, that is, the portion on the side where water enters from the outside into the box strongly adheres closely to the front end surface of the grommet fitting portion, thus improving waterproofness. To do .

Further, the bending deformation in the pressing direction of the grommet by the extension rib is suppressed by the hard inner member, and the extension rib and the grommet are more closely adhered to each other, thereby improving the waterproofness .

Also, the inner member rib receives the compressive force of the grommet by the extension rib , and the grommet's compressive reaction force strongly strengthens the front end surface of the grommet, that is, the portion where water enters the box from the outside to the front end surface of the grommet fitting portion. Since it contacts, waterproofness improves .

Further, when the extension rib presses the grommet, the grommet portion adjacent to the extension rib rises in the direction opposite to the pressing and strongly adheres to the waterproof packing, thereby improving the waterproof property by the waterproof packing.

According to the second aspect of the present invention, electrical components such as relays, fuses and fusible links in the box, circuits such as circuit boards and bus bars, etc. are reliably waterproofed, and the reliability of electrical connection is extended for a long time. Secured across.

  1 to 3 show an embodiment of a waterproof grommet mounting structure and an electric junction box having the waterproof grommet mounting structure.

  In FIG. 1, reference numeral 2 denotes a synthetic resin lower cover, reference numeral 3 indicated by a chain line denotes a synthetic resin upper cover, and reference numeral 4 denotes a synthetic rubber elastic waterproof grommet (fitted in the opening 5 of the lower cover 2). (Hereinafter referred to as grommets). 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 3 is an enlarged view of a main part B of FIG.

  The lower cover 2 and the upper cover 3 constitute a substantially rectangular box 6, and electrical components (not shown) such as relays, fuses and fusible links are mounted in the lower cover to constitute the electrical connection box 1. An upper cover 3 is fixed to the lower cover 2 by locking or fixing means, and a bracket (not shown) of the lower cover 2 is fixed to, for example, an engine room of the vehicle body.

  The grommet 4 includes a horizontal bellows portion 7, a small-diameter cylindrical portion (not shown) following the distal end side of the bellows portion 7, and a vertical flange portion 8 formed on the proximal end side of the bellows portion 7. It is configured. A wire harness (a plurality of electric wires) (not shown) is inserted in the bellows portion so as to be freely bent and connected to each electrical component on the under cover side, and is waterproofed by, for example, tape winding at the cylindrical portion on the grommet tip side. Fixed.

  As shown in FIG. 3, the flange 8 has a straight straight upper end wall 9, a flat upper end surface 9 a of the upper end wall 9, a vertical front rib (lip) 10 that presses against the upper cover 3, and an upper And a vertical rear rib 12 that presses against the waterproof packing 11 attached to the cover 3. The front rib 10 is thinner than the rear rib 12 and is tapered in a tapered shape. The rear rib 12 protrudes substantially straight and has a curved surface with a semicircular cross section at the tip. The protruding heights of both ribs 10 and 12 are approximately the same.

  The front end portion of the rib 10 on the front side is pressed against the inner surface of the horizontal wall portion 13 of the upper cover 3 to have an appropriate allowance, and there is a slight gap between the inner surface of the upper cover 3 and the upper end surface 9a of the flange portion 8. A gap 14 is formed. The rear rib 12 enters the inside of the packing 11 on the upper cover side over substantially the entire length. The lower half of the front end face of the packing 11 is exposed in the gap 14. A small horizontal rib (lip) 16 protrudes from the front end surface 15 of the flange portion 8 and is in close contact with the front end surface 17a which is the inner surface of the front end wall (outer wall) 17 of the upper cover 3.

  A vertical wall portion 19 of the upper cover 3 is adjacent to the rear side of the packing 11 between the rear rib 12 and the rear end face 18 of the flange portion 8 behind the rear rib 12. The ribs are extended (projected) longer than the end surface 9a in a rib shape, and the extension rib 20 presses the upper end surface 9a of the flange portion 8 downward and enters the inside of the flange portion 8 (bites in). ).

  The collar portion 8 is compressed downward and forward by the volume of the extension rib 20, and the collar portion 8 closely adheres to the inner surface of the vertical front end wall 17 of the upper cover 3 and the hard inner member 21 made of synthetic resin on the lower side. To do. Further, the extension rib 20 is in close contact with the flange portion 8. As a result, the waterproof property between the upper cover 3 and the flange portion 8 of the grommet 4 is improved.

  The inner member 21 is formed in a substantially annular shape, and an upper wall 22 corresponding to the flange portion 8 of the grommet 4 is formed horizontally and straight, and enters the upper wall 22 substantially below the rib 10 on the front side of the flange portion 8. It has a vertical rib 23 and a vertical rib 24 that abuts the rear end face 18 of the flange 8, and a groove 25 is formed between the front and rear ribs 23, 24, and the latter half of the flange 8 is in the groove. Are fitted, and the vertical front end 25 of the flange 8 is located in close contact between the front rib 23 and the front end wall 17 of the upper cover 3, and the front end 25 is the horizontal bellows 7 (FIG. 2). Followed by

  The rib 24 on the rear side of the inner member 21 protrudes slightly higher than the rib 23 on the front side, and the tip of the extension rib 20 of the upper cover 3 is located at a slight distance above the front side of the tip of the rear rib 24. Yes. Thus, since the extension rib 20 is close to the rib 24 on the rear side of the inner member 21, the flange portion 8 of the grommet 4 compressed by the extension rib 20 is directed not to the rear but to the front, that is, a portion requiring waterproofing. Due to elastic deformation, the front end surface 15 of the flange portion 8 is in close contact with the inner surface of the front end wall 17 of the upper cover 3. Thereby, waterproofness improves as mentioned above.

  1 and 2, the flange portion 8 of the grommet 4 protrudes outward at the lower end portion and both side portions, and the guide wall 26 of the lower cover 2 is fitted and positioned on the outer periphery of the flange portion 8. Is provided with an air vent / drain hole 27, and a short rib 28 is provided on the inner surface of the guide wall 26 so as to be in close contact with the groove 29 on the outer periphery of the flange 8, and the groove 29 is the upper end of the flange 8. It is located on the substantially same vertical plane as the rear rib 12. The outer peripheral surface of the inner member 21 is in close contact with the inner peripheral surfaces of the lower end portion and both side portions of the flange portion 8, the front rib 23 of the inner member 21 is fitted into the groove 30 of the flange wall 8, and the rear rib 24. Is in close contact with the rear end surface 18 of the flange portion 8, and the engaging protrusion 32 of the rear rib 24 is engaged with the locking frame piece 31 of the lower cover 2 at the lower end portion.

  4 shows a front view of the grommet, and FIG. 5 shows a similar top view.

  As shown in FIG. 4, the grommet 4 has a shape in which the lower half of the semicircular shape and the upper half of the rectangular shape are integrated as in the conventional case, and the lower half and both sides are within the opening of the lower cover 2 (FIG. 2). And the upper end portion is brought into close contact with the upper cover 3 (FIG. 2). Reference numeral 7 denotes an accordion portion, 33 denotes a cylindrical portion on the tip side, 10 denotes a rib on the front side, 9a denotes an upper end surface, and 16 denotes a rib (lip) on the front side.

  As shown in FIG. 5, the front and rear ribs 10, 12 are formed to protrude in parallel on the upper end surface 9 a of the grommet 4, and the front and rear ribs 10, 12 are integrally connected by connecting ribs 34 at both ends of the grommet 4. It is connected to. A flat surface 9a ', which is a part of the upper end surface 9a, is positioned behind the rear rib 12, and the extension rib 20 of the upper cover 3 in FIG. 3 is pressed against the surface 9a'.

  6 is a front view of the lower cover, and FIG. 7 is a sectional view taken along the line CC of FIG.

  An opening 5 is provided in a vertical outer peripheral wall 35 of the lower cover 2, a substantially U-shaped guide wall (grommet fitting portion) 26 is provided around the opening 5, and a groove 36 is provided inside the guide wall 26. Then, the lower half and both side portions of the flange portion 8 of the grommet 4 (FIG. 4) are fitted into the groove portion in a sliding manner from above and brought into close contact with each other. The upper end 26 a of the guide wall 26 in this example is positioned slightly lower than the outer peripheral wall 35, and the upper part of the grommet 4 protrudes above the guide wall 26. On the inner side of the guide wall 26, the rib 28, the locking frame piece 31 and the like are formed.

  FIG. 8 is a front view of the upper cover, FIG. 9 is also a plan view seen from below, and FIG. 10 is a sectional view taken along the line DD in FIG.

  A guide wall (grommet fitting portion) 37 is protruded from the vertical outer peripheral wall 19 of the upper cover 3 so as to protrude downward in a substantially U-shape and forwardly from the outer peripheral wall 19. At the same time that the upper cover 3 is assembled to the lower cover 2, the guide wall 37 of the upper cover 3 is joined (merged) with the guide wall 26 on the lower cover side, and the upper part of the grommet 4 is slidably fitted inside the upper guide wall 37. Match.

  The guide wall 37 is composed of a lower half portion 38 on both sides having a substantially L-shaped cross section, and an upper half portion 39 sealed on the left, right, front, and upper sides. A groove 40 for fitting the upper end of the portion 8 is provided, a groove 41 for fitting the packing 11 is provided inside the guide wall 37 adjacent to the groove 40, and presses against the grommet 4 inside the groove 41. An extension rib 20 is formed to hang down, and the extension rib 20 is located substantially on the same plane as the inner surface of the outer peripheral wall 19. The extension rib 20 continues in the horizontal direction along the outer peripheral wall 19 and presses against the upper end surface 9 a while traversing the upper end surface 9 a of the grommet 4. The effect of the extension rib 20 is as described above. The lower end portion 42 of the guide wall 37 is positioned so as to cover the outer side of the guide wall 26 of the lower cover 2.

  In the above embodiment, the upper cover 3 and the lower cover 2 constitute the box 6, but for example, the upper cover, the middle cover, and the lower cover constitute a box, and the opening 5 and the guide wall 26 are formed in the lower cover. It is also possible to provide the middle cover with the upper guide wall 37 and the extension rib 20.

  It is also possible to provide the opening 5 and the guide wall 26 in the upper cover or middle cover, turn the grommet 4 upside down and fit the upper opening 5, and provide the extension rib 20 and the like on the lower cover.

  Further, the extension rib 20 of the upper cover 3 is opposed not to the rear end of the upper end surface 9a of the grommet 4 but to the center (between the front and rear ribs 10, 12) or the front (front of the front rib 14). It is also possible to provide it. In this case, the rear end wall 43 (FIG. 3) constituting the packing fitting groove 41 is located in contact with or not in contact with the upper end surface 9 a of the grommet 4.

  Further, it is possible to use a member having a higher grommet rigidity by removing the hard inner member 21 in the grommet, and in this case, the extension rib 20 of the cover 3 bites into the grommet. Adheres closely and improves waterproofness. Further, the inner member 21 can be integrally formed on the grommet 4 by insert molding or the like.

  It is also possible to use a grommet 4 without the bellows portion 7. In this case, for example, the small-diameter cylindrical portion 33 (FIG. 4) is integrated with the flange portion 8, and the electric wire is fixed to the cylindrical portion 33 by tape winding or the like.

  Further, in the above embodiment, the guide wall 37 that is a grommet fitting portion is provided on the upper cover 3, but the vertical front end wall 17 of the guide wall 37 is eliminated, and the grommet 4 is formed only on the horizontal upper wall 13 side. It is also possible to press the upper end portion of the flange portion 8. Even in this case, it goes without saying that the extension rib 20 is provided on the upper wall 13. Although the packing 11 has never existed, even if it does not, the extension rib 20 provides a considerable sealing performance. It is also possible to eliminate the ribs 16 on the front end face 15 of the flange 8 of the grommet 4 and to bring the front end face 15 into close contact with the front end face 17a of the upper cover 3 directly.

It is a top view which shows one Embodiment of the attachment structure of the waterproof grommet which concerns on this invention, and an electrical junction box provided with the same. It is AA sectional drawing of FIG. It is the B section enlarged view of FIG. It is a front view which shows a grommet. It is a top view which similarly shows a grommet. It is a front view which shows a lower cover. It is CC sectional drawing of FIG. It is a front view which shows an upper cover. It is a bottom view top view which similarly shows an upper cover. It is DD sectional drawing of FIG. It is a disassembled perspective view which shows the attachment structure of the conventional waterproof grommet, and one form of an electrical junction box provided with the same. It is a longitudinal cross-sectional view which similarly shows an assembly state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrical junction box 2 Lower cover 3 Upper cover 4 Waterproof grommet 5 Opening part 6 Box 9a Upper end surface 11 Waterproof packing 15, 17a Front end surface 18 Rear end surface 20 Extension rib 21 Inner member 24 Rib 37 Guide wall (grommet fitting part)

Claims (2)

Opening is provided in the lower cover, elastic waterproof grommet for wire insertion is fitted in the opening, is the upper cover to the lower cover joined to constitute the box body, the grommet fitting portion of the upper cover The end portion of the waterproof grommet is located on the inside, and a hard inner member is fitted inside the end portion, and a flat surface near the rear end of the upper end surface of the end portion is pressed downward on the grommet fitting portion. extension rib entering deeply downward than the flat surface is protruded toward narrower longitudinal than the flat surface with the front end surface intersecting the upper end surface of the end portion abuts the front end face of the grommet fitting portion The inner member rib abuts against the rear end surface of the end portion, a waterproof packing is provided in the groove of the grommet fitting portion adjacent to the extension rib, and the end portion adjacent to the extension rib Ribs that enter the waterproof packing are provided on the upper end surface of the Simultaneously with the extension rib bites down into the flat surface of the end portion, the mounting structure of the waterproof grommet rib of the upper end face, characterized in that the entering upwardly into waterproof the packing.   An electrical junction box comprising the waterproof grommet mounting structure according to claim 1.

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