Grommet and method of mounting thereof

A grommet (10) according to an embodiment of the present invention includes a wire harness connecting part (11) which is liquid-tightly connected to a wire harness (20), a panel connecting part (13) which can be liquid-tightly connected to a panel opening (31), an extending part (12) shape-changeably extending between the wire harness connecting part (11) and the panel connecting part (13), and an extending-part-shape maintaining part (12a) which maintains a shape of the extending part (12) in a state where a distance between the wire harness connecting part (11) and the panel connecting part (13) in a length direction of the wire harness (20) is shorter than that of the case where the panel connecting part (13) is liquid-tightly connected to the panel opening (31).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase application of International Application No. PCT/JP2011/050524, filed Jan. 14, 2011, the content of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a grommet attached to a wire harness and a method of mounting the grommet to a panel opening. In particular, the present invention relates to a grommet which is able to make room for a work space for attaching a connector at a tip of the wire harness to a corresponding connector in a junction box placed in the panel opening and a method of mounting the grommet to the panel opening.

BACKGROUND ART

Conventionally, a waterproof grommet attached to a wire harness for improving the connecting workability of a connector at a panel opening is known (see Patent Document 1 for example).

This waterproof grommet is configured to be fixed to a panel by using two bolts. When the connector is connected to the corresponding connector, the waterproof grommet is rotated 90 degrees with respect to a normal fixed position about a bolt axis as a rotational axis. Thus, a waterproof grommet body is displaced from the panel opening. As a result, the waterproof grommet can make room for a space for a connecting procedure of the connectors.

Also, a side wall of this waterproof grommet is comprised of a stretchable bellows part. The waterproof grommet can completely expose the connectors within the bellows when the bellows are compressed. As a result, the waterproof grommet can rotate about the bolt axis as the rotational axis while avoiding interference with the connectors.

PRIOR ART DOCUMENTS

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, in a case of mounting the waterproof grommet in Patent Document 1 to the panel opening, a worker has to compress the bellows part of the waterproof grommet to avoid interference between the side wall of the waterproof grommet and the connectors when the worker rotates the waterproof grommet about the bolt axis as the rotational axis to make room for a space for the connecting procedure of the connectors, or when the worker returns the rotated waterproof grommet to the normal fixed position after the connection procedure of the connectors has been completed. Thus, it cannot be said that the connecting workability has sufficiently improved.

Also, even if the worker makes room for the work space by rotating the waterproof grommet by 90 degrees, the worker cannot completely avoid the interference between a flange part of the waterproof grommet and the connectors. Thus, also in this regard, it cannot be said that the connecting workability has sufficiently improved.

In consideration of the above point, the present invention is intended to provide a grommet which further improves the connecting workability of a connector and a method of mounting the grommet to a panel opening.

Means for Solving Problems

To achieve the above objective, a grommet according to an embodiment of the present invention includes a wire harness connecting part configured to be liquid-tightly connected to a wire harness, a panel connecting part configured to be able to be liquid-tightly connected to a panel opening, an extending part configured to shape-changeably extend between the wire harness connecting part and the panel connecting part, and an extending-part-shape maintaining part configured to maintain a shape of the extending part in a state where a distance between the wire harness connecting part and the panel connecting part in a length direction of the wire harness is shorter than that of the case where the panel connecting part is liquid-tightly connected to the panel opening.

Also, a method of mounting a grommet to a panel opening according to an embodiment of the present invention, the grommet comprising a wire harness connecting part configured to be liquid-tightly connected to a wire harness, a panel connecting part configured to be able to be liquid-tightly connected to a panel opening, an extending part configured to shape-changeably extend between the wire harness connecting part and the panel connecting part, and an extending-part-shape maintaining part configured to maintain a shape of the extending part, includes steps of connecting a connector at a tip of the wire harness and a corresponding connector disposed in the panel opening while maintaining by the extending-part-shape maintaining part the shape of the extending part in a state where a distance between the wire harness connecting part and the panel connecting part in a length direction of the wire harness is shorter than that of the case where the panel connecting part is liquid-tightly connected to the panel opening, and coupling the panel connecting part to the panel opening by lengthening the distance through changing the shape of the extending part.

Effects of the Invention

According to the above means, the present invention can provide a grommet which further improves the connecting workability of a connector and a method of mounting the grommet to a panel opening.

MODE FOR CARRYING OUT THE INVENTION

With reference to figures, a mode for carrying out the present invention will be explained below.

FIG. 1is a partial cross-sectional view illustrating a configuration example of a grommet10according to an embodiment of the present invention, in which a whole extent of the grommet10and a part of a wire harness20are seen in cross-section (shadow areas).FIG. 1shows a state before the grommet10attached to the wire harness20is connected to a dash panel30. Connectors21(21a,21b, and21c), at a tip of the wire harness20to which the grommet10is attached, pass through a panel opening31of the dash panel30from an engine room ER side at a front part of a vehicle. Also, the connectors21have been connected to corresponding connectors in a junction box40of an instrument panel installed in a vehicle interior VI (a space where an air conditioning unit and the like are installed).FIG. 2is a diagram illustrating a plane defined by a line II-II inFIG. 1viewed from a direction of an arrow AR1.

The grommet10is a member made of synthetic rubber such as Ethylene Propylene Diene Monomer (EPDM) rubber. The grommet10is mainly comprised of a wire harness connecting part11, an intermediate extending part12, and a panel connecting part13.

The wire harness connecting part11is configured to be connected to an outer periphery of the wire harness20liquid-tightly. For example, the wire harness connecting part11has a cylindrical shape, and is bonded to the wire harness20liquid-tightly by applying an adhesive such as a modified silicone resin adhesive between an outer surface of the wire harness20and an inner surface of the wire harness connecting part11.

The wire harness connecting part11may be cured in a shape which fits into the wire harness20(typically a cylindrical shape) at a state where it remains connected to the wire harness20.

The intermediate extending part12is a shape-changeable flexible part extending between the wire harness connecting part11and the panel connecting part13. For example, the intermediate extending part12has an extending-part-shape maintaining part12afor maintaining its shape in a reflexed state (a rolled-up state) to a direction opposite to an extending direction of the wire harness20(opposite to a direction facing the tip where there are the connectors21).

The extending-part-shape maintaining part12ais made of the same material (for example, EPDM rubber) as other parts (the wire harness connecting part11and the panel connecting part13) of the grommet10. The extending-part-shape maintaining part12ais configured so that it can maintain the rolled-up state of the intermediate extending part12as shown inFIG. 1. For example, the extending-part-shape maintaining part12ais configured to be thicker than other parts or to be coated with a curing agent so that it can maintain its shape, regardless of the state of the intermediate extending part12(regardless whether it is rolled up or not).

Preferably, the grommet10is supplied in a state where the intermediate extending part12has been rolled up. This is to allow the worker to begin the connecting procedure of the connectors without the need to roll up the intermediate extending part12manually.

The panel connecting part13is configured to be connected to the periphery of the panel opening31of the dash panel30liquid-tightly. For example, the panel connecting part13has an opening which fits into a shape of the periphery of the panel opening31(for example, a rectangle). Also, the periphery of the panel connecting part13is reinforced by a plate part14so that the periphery can enable fastening by a fastener member such as a bolt.

The panel connecting part13ensures rigidity higher than that of the intermediate extending part12by making a joint part13a,13battached to the intermediate extending part12thicker than the intermediate extending part12. In case where the intermediate extending part12is rolled up as shown inFIG. 1, the panel connecting part13helps the intermediate extending part12form a curved part12bwhich reflexes the intermediate extending part12, which has been rolled up by the extending-part-shape maintaining part12ain the direction opposite to the extending direction of the wire harness20, again in the extending direction of the wire harness20in the immediate vicinity of the joint part13a,13b.

As a result, in case where the intermediate extending part12is rolled up as shown inFIG. 1, the panel connecting part13is held in a position away from the dash panel30more than a predetermined distance D (for example, 150 mm) at a state where the connectors21of the wire harness20are connected to the corresponding connectors in the junction box40. Thus, the panel connecting part13allows the grommet10to make room for a work space (a space into which the worker can insert his/her hand, also referred to as “hand space”) required for the worker to connect the connectors21of the wire harness20to the corresponding connectors in the junction box40.

The plate part14is configured to reinforce the periphery of the panel connecting part13. For example, the plate part14is made of metal such as an iron, and fastened, together with the panel connecting part13, to the dash panel30by the fastener member such as a bolt.

In the present embodiment, the panel connecting part13(the plate part14) has a rectangle shape which fits into the shape (the rectangle shape) of the periphery of the panel opening31as shown inFIG. 2. However, if the panel connecting part13(the plate part14) can seal the panel opening31liquid-tightly, it does not necessarily fit into the shape of the panel opening31, so that it may have an opening having other shapes such as a circular shape, an elliptical shape, a polygonal shape, or the like.

Also, in the present embodiment, the wire harness20is provided with three connectors21a,21b, and21cat its tip. These connectors pass through the single panel opening31and are connected to the corresponding connectors in the junction box40. However, the wire harness20may be provided with one or two connectors at its tip, or may be provided with more than three connectors.

Along withFIG. 1,FIG. 3is a partial cross-sectional view illustrating a configuration example of the grommet10according to the embodiment of the present invention.FIG. 3shows a state after the grommet10has been connected to the dash panel30. Also,FIG. 4is a diagram illustrating a plane defined by a line IV-IV inFIG. 3viewed from a direction of an arrow AR2.

After the worker has connected the connectors21of the wire harness20to the corresponding connectors in the junction box40manually, the worker rolls out the intermediate extending part12, which has been rolled up as shown inFIG. 1, in a direction toward the dash panel30. Then, the worker brings the panel connecting part13into close contact with an engine-room-side surface30a(seeFIG. 1) at the periphery of the panel opening31of the dash panel30. And then, the worker fastens the panel connecting part13, together with the plate part14, to the dash panel30by using bolts32a-32d(seeFIG. 4) inserted into respective bolt holes15a-15d(seeFIG. 2) which pierce through the panel connecting part13and the plate part14.

As shown inFIGS. 1 and 3, the extending-part-shape maintaining part12amaintains its shape (a state where it is reflexed in the opposite direction to the extending direction of the wire harness20) both in the case where the intermediate extending part12has been rolled up in the opposite direction to the direction toward the dash panel30and the case where the intermediate extending part12has been rolled out in the direction toward the dash board30.

Thus, if the intermediate extending part12has been rolled out in the direction toward the dash panel30as shown inFIG. 3, it forms the curved part12bby reversing its extending direction to the extending direction of the wire harness20at a point nearby the extending-part-shape maintaining part12awhich is in a state reflexed to the direction opposite to the extending direction of the wire harness20, and then extends toward the dash panel30.

Also, the worker can return the intermediate extending part12to the rolled-up state shown inFIG. 1by manually rolling up again the intermediate extending part12which has been rolled out toward the dash panel30as shown inFIG. 3, by taking advantage of a characteristic of the extending-part-shape maintaining part12awhich maintains its shape regardless of a state of the intermediate extending part12.

Due to the above configuration, the grommet10can hold the intermediate extending part12in the rolled-up state to the direction opposite to the extending direction of the wire harness20when the worker connects the connectors21of the wire harness20to the corresponding connectors in the junction box40. Thus, the grommet10can make room for a work space for the connecting procedure without a special manual procedure by the worker, and can further improve the workability.

Also, the grommet10can go back and forth repeatedly between a state where the intermediate extending part12has been rolled up and a state where the intermediate extending part12has been rolled out. Thus, the worker can make room for a work space by rolling up the intermediate extending part12even in the case where the worker starts over the connecting procedure of the connectors21of the wire harness20again after the worker has rolled out the intermediate extending part12.

Also, the intermediate extending part12is held in a state where the panel connecting part13has been eventually directed toward the dash panel30by reversing its extending direction at two points, i.e., at the extending-part-shape maintaining part12aand at the curved part12b. However, the intermediate extending part12may be, without forming the curved part12b, held in a state where the panel connecting part13has been rolled up and directed to a direction opposite to the direction toward the dash panel30(a state where the intermediate extending part12and the panel connecting part13have been turned inside out completely in comparison to a state where the panel connecting part13is connected to the dash panel30).

Next, referring toFIGS. 5-8, a grommet10A according to another embodiment of the present invention will be described. Components common to the grommet10shown inFIGS. 1-4are referred to by the same reference numerals.

FIG. 5is a partial cross-sectional view illustrating a configuration example of the grommet10A according to another embodiment of the present invention, in which a whole extent of the grommet10A and a part of a wire harness20are seen in cross-section (shadow areas).FIG. 5shows a state before the grommet10A is connected to a dash panel30. Connectors21(21a,21b, and21c), at a tip of the wire harness20to which the grommet10A is attached, pass through a panel opening31of the dash panel30from an engine room ER side at a front part of a vehicle. Also, the connectors21have been connected to corresponding connectors in a junction box40of an instrument panel installed in a vehicle interior VI (a space where an air conditioning unit and the like are installed).FIG. 6is a diagram illustrating a plane defined by a line VI-VI inFIG. 5viewed from a direction of an arrow AR3.

The grommet10A is different from the grommet10inFIGS. 1-4in that it has an intermediate extending part12A provided with a bellows structure part12c, and an extending-part-shape maintaining part12aA for maintaining a state where the bellows structure part12cis folded. However, other parts of the grommet10A are in common with the grommet10. Thus, an explanation relevant to the common points is omitted, and the differences will be explained in detail.

The intermediate extending part12A is a shape-changeable flexible part (a part of the grommet10A) extending between a wire harness connecting part11and a panel connecting part13. The intermediate extending part12A is provided with the bellows structure part12cwhich changes its shape from a folded state where the panel connecting part13is held in a position away from the dash panel30more than a predetermined distance D (for example, 150 mm) when the connectors21of the wire harness20have been connected to the junction box40, to a stretched state where the panel connecting part13is brought into close contact with the dash panel30.

The extending-part-shape maintaining part12aA is a component of the intermediate extending part12. The extending-part-shape maintaining part12aA is made of the same material (for example, an EPDM rubber) as other parts of the grommet10A (the wire harness connecting part11and the panel connecting part13). The extending-part-shape maintaining part12aA includes bellows-structure-part folding tongue-parts12aA1,12aA2and a tongue-part holding tape12aA3.

The bellows-structure-part folding tongue-parts12aA1,12aA2are configured to extend from joint parts between the bellows structure part12cand the panel connecting part13in a direction opposite to the extending direction of the wire harness20. The bellows-structure-part folding tongue-parts12aA1,12aA2can maintain the folded state of the bellows structure part12cby holding respective free ends in contact with an outer surface of the wire harness connecting part11while maintaining the folded state of the bellows structure part12c.

The tongue-part holding tape12aA3is a holding member for holding the respective free ends of the bellows-structure-part folding tongue-parts12aA1,12aA2in contact with the outer surface of the wire harness connecting part11. For example, the tongue-part holding tape12aA3is an annular elastic member placed on an outer periphery of the wire harness20(the wire harness connecting part11) stretchably. The tongue-part holding tape12aA3may be made of material different from those of other parts of the grommet10A.

Preferably, the grommet10A is supplied in a state where the bellows structure part12cof the intermediate extending part12A is folded.

In the present embodiment, as shown inFIG. 6, the extending-part-shape maintaining part12aA is configured to include the two bellows-structure-part folding tongue-parts12aA1,12aA2placed at respective sides (upper and lower sides) of the wire harness20with respect to a central axis of the wire harness20. However, the extending-part-shape maintaining part12aA may include a single bellows-structure-part folding tongue-part or more than two bellows-structure-part folding tongue-parts.

Also, in the present embodiment, the bellows-structure-part folding tongue-parts12aA1,12aA2are held in contact with the outer periphery of the wire harness20(the wire harness connecting part11) by using the tongue-part holding tape12aA3. However, the bellows-structure-part folding tongue-parts12aA1,12aA2may be peelably held in contact with the outer periphery of the wire harness20(the wire harness connecting part11) by using an adhesive such as a modified silicone resin adhesive.

Along withFIG. 5,FIG. 7is a partial cross-sectional view illustrating a configuration example of the grommet10A.FIG. 7shows a state after the grommet10A has been connected to the dash panel30. Also,FIG. 8is a diagram illustrating a plane defined by a line VIII-VIII inFIG. 7viewed from a direction of an arrow AR4.

After the worker has manually connected the connectors21of the wire harness20to the corresponding connectors in the junction box40, the worker releases the respective free ends of the bellows-structure-part folding tongue-parts12aA1,12aA2by cutting the tongue-part holding tape12aA3, or by displacing the tongue-part holding tape12aA3in the direction opposite to the extending direction of the wire harness20.

Subsequently, the worker stretches the bellows structure part12cof the intermediate extending part12which is in the folded state as shown inFIG. 5so that the bellows structure part12cspreads toward the dash panel30. Then, as shown inFIG. 7, the worker brings the panel connecting part13into close contact with an engine-room-side surface30a(seeFIG. 5) at the periphery of the panel opening31of the dash panel30. And then, the worker fastens the panel connecting part13, together with the plate part14, to the dash panel30by using bolts32a-32d(seeFIG. 8) inserted into respective bolt holes15a-15d(seeFIG. 6) which pierce through the panel connecting part13and the plate part14.

Also, the worker can manually fold again the bellows structure part12cwhich has been extended in the direction toward the dash panel30as shown inFIG. 7. Then, the worker can hold again the respective free ends of the bellows-structure-part folding tongue-parts12aA1,12aA2in contact with the outer surface of the wire harness connecting part11by using the tongue-part holding tape12aA3which has been displaced to the direction opposite to the extending direction of the wire harness20. And thus, the worker can also return the bellows structure part12cto the folded state as shown inFIG. 5.

Due to the above configuration, the grommet10A holds the bellows structure part12cof the intermediate extending part12A at the folded state when the worker connects the connectors21of the wire harness20to the corresponding connectors in the junction box40. Thus, the grommet10A can make room for a work space for the connecting procedure without a special manual procedure by the worker, and can further improve the workability.

Also, the grommet10A can go back and forth repeatedly between a state where the bellows structure part12chas been folded and a state where the bellows structure part12chas been stretched in case where the worker releases the bellows-structure-part folding tongue-parts12aA1,12aA2from the outer surface of the wire harness connecting part11by displacing the tongue-part holding tape12aA3. Thus, the worker can make room for a work space by folding the bellows structure part12ceven in the case where the worker starts over the connecting procedure of the connectors21of the wire harness20again after the worker has stretched the bellows structure part12c.

Also, the grommet10A can be stretched so that the bellows structure part12cin the folded state spreads toward the dash panel30. Thus, a size of an opening of the panel connecting part13can be set flexibly. And thus, the grommet10A can fit into panel openings with a variety of sizes including a panel opening with relatively large size which allows plural connectors to pass through.

Also, the bellows structure part12cmay be configured to be stretched cylindrically along the wire harness20without spreading. In that case, a flat plate part having a size about equal to the size of the opening of the panel connecting part13may be placed at the joint part between the wire harness connecting part11and the intermediate extending part12A (the bellows structure part12c).

Also, as shown inFIG. 5, the bellows structure part12cis held so that its folded part is piled up in a direction perpendicular to the outer surface of the wire harness20. However, the bellows structure part12cmay be held so that its folded part is piled up in a direction parallel to the outer surface of the wire harness20.

Also, the bellows structure part12cmay be held so that its folded part is piled up in the direction opposite to the extending direction of the wire harness20beyond the direction perpendicular to the outer surface of the wire harness20.

The preferable embodiments of the present invention have been explained in detail. However, the present invention shall not be restricted to the above embodiments. Various changes and substitutions may be made to the above embodiments without departing from the scope of the present invention.

For example, in the above embodiment, the grommet10A holds the bellows structure part12cin the folded state by using the bellows-structure-part folding tongue-part12aA1,12aA2and the tongue-part holding tape12aA3. However, the grommet10A may omit the bellows-structure-part folding tongue-part12aA1,12aA2and the tongue-part holding tape12aA3. In that case, the grommet10A may hold the flexible intermediate extending part12A without the bellows structure in a state rolled up toward the direction opposite to the extending direction of the wire harness20, by peelably bonding a part thereof (for example, a joint part between the intermediate extending part12A and the panel connecting part13) to the outer surface of the wire harness connecting part11by using an adhesive.

Also, in the above embodiment, the grommet10A may omit the bellows-structure-part folding tongue-part12aA1,12aA2and the tongue-part holding tape12aA3. On that basis, the grommet10A may be configured to partially change thickness or flexibility of the intermediate extending part12A. Thus, the grommet10A can generate a certain shape-maintaining force which enables the folded state of the bellows structure part12cto be maintained, and may allow the worker to exert a force on the bellows structure part12cand to bring the panel connecting part13into close contact with the dash panel30. And thus, when the worker gets his/her hands off of the bellows structure part12c, the grommet10A may allow the bellows structure part12cto return to the folded state, and may allow the panel connecting part13to automatically get away from the dash panel30to a predetermined position. In this case, the intermediate extending part12A does not have to employ the bellows structure part12c. The intermediate extending part12A may employ a structure which extends smoothly.

Also, in the above embodiments, the grommets10,10A are attached to the wire harness20having a circular cross-section. However, the grommets10,10A may be attached to a wire harness having other cross-sectional shapes such as an elliptical shape, a rectangle shape, or the like.

EXPLANATION OF REFERENCE NUMERALS