Wire harness water cut-off structure

A main body portion of a grommet is mounted to a through hole of a dash panel partitioning an engine room and a vehicle compartment, a long tube is continuously provided to the main body portion, and the tube is arranged at inside of the engine room. A wire harness is inserted to the main body portion and an inner portion of the tube in an unbundled state, under the state, at least two stages of narrowed portions (first, second fixing portions) constituted by narrowing an inner diameter of the tube at a position proximate to a front end of the tube and a position proximate to the main body portion remote from the position. At the narrowed portion, by fastening a strap for fixing to an outer periphery of the tube, the inner diameter of the tube is narrowed. Wires are scattered by providing a bent portion at the wire harness coming out from the grommet.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wire harness water cut-off structure for preventing water from invading by way of clearances among wires of the wire harness from a side of an engine room to a side of a vehicle compartment when, for example, the wire harness is wired from the side of the engine room to the side of the vehicle compartment by passing the through hole of a dash panel of an automobile.

2. Related Art

In a background art, when a wire harness is wired between to a side of an engine room and a side of a vehicle compartment by way of a through hole of a dash panel, invasion of water by way of a clearance between the wire harness and the through hole is prevented by arranging a grommet between the wire harness and the through hole.

However, by simply mounting the grommet with an object of sealing the clearance between an outer periphery of the wire harness and the panel through hole, in a case in which when inside of the engine room is cleaned by high pressure water, water is brought to clearances of wires of the wire harness at inside of the engine room, it cannot be prevented that the water invades the vehicle compartment side by way of the clearances among the wires.

Hence, a grommet20as shown byFIG. 7is used. The grommet20comprises a main body portion21including a main body portion21and a cylindrical cone portion21band mounted through a through hole31of a panel30of a vehicle body, a small diameter cylindrical portion22continuous to a small diameter side of the cylindrical cone portion, and an inner cylinder wall23provided at an inner portion of the main body portion21and is constructed by a constitution in which in a state of passing a wire harness W through the main body portion21and the small diameter cylindrical portion20, by filling to solidify a seal agent25at an inner portion of the inner cylinder wall23, clearances among wires of a wire exposure portion W2exfoliated with a tape are sealed by the seal agent25.

Further, as a structure of achieving a water cut-off effect without filling a seal agent, there is disclosed a proposal in which an inner portion of a grommet is provided with means for scattering a plurality of wires constituting a wire harness, thereby, water is prevented from invading frontward from the scattered portion (refer to, for example, JP-A-2002-58140).

Further, among these grommets, in order to install the wire harness conveniently within the engine room, there is one in which a bellows tuba is integrated and a strap clamp is attached to a part of the tube so that the wire harness is fixed to the vehicle body with the strap clamp. (See, for example, JP 2000-311534A.)

Meanwhile, the grommet25of a type of using the seal agent25as shown byFIG. 7, poses a problem that time and labor is taken for an operation of filling the seal agent25, and therefore, it is difficult to promote a productivity.

Further, in the case of the grommet described in Patent Reference 1, the inner portion of the grommet is provided with the means for scattering a wire bundle, and therefore, the structure is complicated and cost is increased.

SUMMARY OF THE INVENTION

The invention has been carried out in view of the above-described situation and it is an object thereof to provide a wire harness water cut-off structure capable of cutting off invasion of water by a simple structure without taking time or labor.

In order to achieved the above-described object, a wire harness water cut-off structure according to the invention is characterized in (1) through (8) described below.

(1) A long tube is continuously provided to a main body portion of a grommet mounted to a through hole of a panel of a vehicle body, a wire harness is inserted to the main body portion and an inner portion of the tube in an unbundled state, wider the state, at least two stages of narrowed portions constituted by narrowing an inner diameter of the tube are provided at a position at a vicinity of a front end of the tube and a position proximate to the main body portion remote from the position.
(2) in the wire harness water cut-off structure having a constitution of (1) mentioned above,

at least one of the at least two stages of narrowed portions narrows the inner diameter of the tube by projecting a rib at an inner periphery of the tube.

(3) In the wire harness water cut-off structure having the constitution of (1) mentioned above,

at least one of the at least two stages of narrowed portions narrows the inner diameter of the tube by fastening a strap to an outer periphery of the tube.

(4) In the wire harness water cut-off structure having a constitution of any of (1) through (3) mentioned above

the front end of the tube is directed to a lower side and arranged at a position lower than a height of the main body portion.

(5) in the wire harness water cut-off structure of a constitution of any of (1) through (4) mentioned above,

by providing a bent portion at the wire harness from the narrowed portion provided at the position proximate to the main body portion to a side of the main body portion in the at least two stages of narrowed portions, a plurality of wires constituting the wire harness are scattered between the narrowed portion and the bent portion.

(6) In the wire harness water cut-off structure having a constitution of (5),

the bent portion scattering the plurality of wires is formed at a vicinity of a position at which the wire harness comes out from the main body portion of the grommet by providing a portion of the wire harness fixed to the vehicle body at a vicinity of the position at which the wire harness comes out from the main body portion of the grommet.

(7) In the wire, harness water cut-off structure having a constitution of (6),

the panel of the vehicle body is a dash panel partitioning an engine room and a vehicle compartment of an automobile, in a state of arranging the tube to a side of the engine room, the main body portion of the grommet is fitted to be attached to a through hole of the dash panel, and the portion of the wire harness fixed to the vehicle body is provided at a vicinity of the through hole of the dash panel to thereby arrange the bent portion to an inner side of the vehicle chamber.

(8) In the wire harness water cut-off structure having the constitution of (3),

the tube and the wire harness are fixed to the vehicle body by locking the strap by the vehicle body.

According to the wire harness water cut-off structure having the constitution of (1), the long tube is continuously provided to the main body portion of the grommet, and therefore, water can be made to be difficult to enter an inner portion of the grommet. Further, after inserting the wire harness to the grommet, the inner diameter of the tube is narrowed at least two portions, and therefore, even when attacked by high pressure cleaning water, power of invasion of water can be weakened, invasion of water to a depth side can be held back. Further, the wire harness passed into the tube is brought into an unbundled state, and therefore, even when water accidentally invades inside of the tube, invasion of water by a capillary phenomenon can be restrained as less as possible by a degree of scattering wires. Further, according to the structure, a water cut-off effect can be achieved without taking time and labor since a water cut-off agent is not used, the long tube is provided continuously thereto, and only the inner diameter of the tube is narrowed at a pertinent portion, and therefore, the constitution is simple and can be realized at low cost.

According to the wire harness water cut-off structure having the constitution of (2), by projecting the rib at the inner periphery of the tube, the inner diameter of the tube is narrowed, and therefore, a water cut-off effect by narrowing the inner diameter can be achieved by only passing the wire harness through inside of the tube.

According to the wire harness water cut-off structure having the constitution of (3), the inner diameter of the tube is narrowed by fastening the strap to the outer periphery of the tube, and therefore, the water cut-off effect by narrowing the inner diameter can be achieved by only fastening the strap after passing the wire harness into the tube.

According to the wire harness water cut-off structure having the constitution of (4), by directing the front end of the tube to the lower side and making the front end of the tube lower than the height of the main body portion, invasion of water from the front end of the tube can further be held back.

According to the wire harness water cut-off structure having the constitution of (5), by providing the bent portion at the wire harness from the narrowed portion proximate to the main body portion to the side of the main body portion, a plurality of wires constituting the wire harness are scattered between the narrowed portion and the bent portion, and therefore, even when water accidentally invades by exceeding the narrowed portion, since the wires are firmly scattered between the bent portion and the narrowed portion, further invasion of water by the capillary phenomenon can be stopped.

According to the wire harness water cut-off structure having the constitution of (6), the bent portion for scattering the wires is formed at the vicinity of the position at which the wire harness comes out from the main body portion of the grommet, and therefore, the wires can firmly be scattered by considerably bending the wire harness, and invasion of water by the capillary phenomenon can be held back by enlarging the clearances among the wires.

According to the wire harness water cut-off structure having the constitution of (7), the wire harness is wired between the side of the engine room and the side of the vehicle chamber, by passing the wire harness through the grommet in the state in which the grommet is mounted to the through hole of the dash panel partitioning the engine room and the vehicle chamber, the tube of the grommet is arranged on the side of the engine room, and therefore, a problem of invasion of water to the inner side of the vehicle cheer in a case of cleaning inside of the engine room by high pressure water can be effectively resolved without taking time and labor.

According to the wire harness water cut-off structure having the constitution of (8), the tube and the wire harness are fixed to the vehicle body by locking the strap by the vehicle body, and therefore, the water cut-off effect by narrowing the inner diameter of the tube can be achieved by only fastening the strap for fixing the wire harness.

According to the invention, the wire harness water cut-off structure capable of cutting off invasion of water can be provided by a simpler structure and without taking time and labor.

As described above, the invention has been concisely explained. Further, details of the invention will become further clear by reading the best mode for carrying out the invention explained below in reference to the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferable embodiments according to the invention will be explained in details in reference to the drawings as follows.

FIG. 1is a side view of a wire harness water cut-off structure according to a first embodiment of the invention.

The water cut-off structure of the first embodiment is applied to a case of wiring a wire harness W by way of a through hole31of a dash panel30partitioning an engine room X and a vehicle compartment Y. A grommet1used here includes a main body portion2mounted to the through hole31of the dash panel31and a long tube3continuously provided to the main body portion2. A principal length portion of the tube3is provided with a flexibility by thin-walling a peripheral wall thereof and forming the portion by a shape of a bellows.

The grommet1is fixed to the dash panel30in a state of arranging a side of extending the tube3at inside of the engine room X by fitting to attach the main body portion2to the through hole31of the dash panel30. Further, since integrally provided with the long tube3, the wire harness W at inside of the tube3is fixed to the vehicle body along with the tube3by attaching a strap10at a pertinent position of the wire harness W covered by the tube3and locking the strap by the vehicle body. Portions thereof fixed by the straps10are provided at two portions of a first fixing portion A at a vicinity of a front end3aof the tube3and a second fixing portion B proximate to the main body portion2remote from the position. The front end3aof the tube3is directed to a lower side and is arranged at a position lower than a height of the main body portion2.

In this case, at the first, the second fixing portions A, B, an inner diameter of the tube3is narrowed by strongly fastening the strap10from an outer periphery of the tube3, and the portions respectively constitute narrowed portions narrowing the inner diameter of the tube3.

Further, as shown byFIG. 1andFIG. 2, the wire harness W is inserted to an inner portion of the grommet1in an unbundled state, and a bent portion W1is formed at the wire harness W coming out from the grommet1by providing a third fixing portion C for fixing the wire harness W to the dash panel30at a vicinity of a position at which the wire harness W comes out from the main body portion2from the grommet1to inside of the vehicle chamber W. At the bent portion W1, by bending the wire harness W in the unbundled state by a small radius of curvature, a plurality of wires are naturally scattered and clearances among the wires of the portion are enlarged.

According to the water cut-off structure having the above-described constitution, the long tube3is continuously provided to the main body portion2of the grommet1, and therefore, water can be made to be difficult to enter an inner portion of the grommet1. Further, the wire harness W is inserted through the grommet1, thereafter, the inner diameter of the tube3is narrowed at two portions (first, second fixing portions A, B), and therefore, even when attached by high pressure cleaning water, power of invasion of water can be weakened and invasion of water to a depth side can be held back. It is naturally further preferable that the narrowed portion (fixing portion) of narrowing the inner diameter of the tube3in this way is further provided other than the first, the second fixing portions A, B to provide the narrowed portions at 3 or more portions.

Further, the wire harness W passing through inside of the tube3is brought into the unbundled state, and therefore, even when water accidentally invades inside of the tube3, invasion of water by a capillary phenomenon can be restrained as less as possible by a degree of scattering the wires.

Further, the front end3aof the tube3is directed to the lower side, the front end3aof the tube3is arranged to be lower than the height of the main body portion2, and therefore, invasion of water from the front end of the tube can further be held back.

Further, by providing the bent portion W1at the wire harness W from the second fixing portion B proximate to the main body portion2to the side of the main body portion2, a plurality of wires constituting the wire harness W are scattered between the bent portion W1and the second fixing portion B, and therefore, even when water invades accidentally by exceeding the second fixing portion B, the wires are firmly scattered between the bent portion W1and the second fixing portion B, and therefore, further invasion of water by the capillary phenomenon can be stopped. Further, so far as the clearances among the wires of the wire harness W can be ensured to a degree of not hampering a function of stopping invasion of water by the capillary phenomenon, the portion of the wire harness W at a vicinity of the bent portion W1may be fixed to the main body portion2of the grommet2by an adhering tape or the like.

Further, according to the first embodiment, the inner diameter of the tube3is narrowed by fastening the strap10for fixing to the outer periphery of the tube3, and therefore, water cut-off effect by narrowing the inner diameter can be achieved by only fastening the strap10for fixing after passing the wire harness W into the tube3.

Further, according to the structure, the water cut-off effect can be achieved without taking time and labor since the water cut-off agent is not used, the long tube3is continuously provided, and the inner diameter of the tube3is only narrowed at the pertinent portion, and therefore, the constitution is simple and can be realized at low cost.

Second Embodiment

FIG. 4Ais a side view showing a state of attaching a grommet according to a second embodiment,FIG. 4Bis a sectional view enlarging Ib portion ofFIG. 4A,FIG. 5is an outlook view showing a portion of a tube ofFIG. 4B,FIG. 6is a perspective view showing a modified example of the portion of the tube ofFIG. 5.

A grommet101of the second embodiment includes a grommet main body portion102mounted to a through hole131of a dash panel130, and a long tube103continuously provided to the grommet main body portion102. A principal length portion of the tube103is provided with a flexibility by thin-walling a peripheral wall thereof and being formed in a shape of a bellows.

The grommet101is fixed to the dash panel130by fitting to attach the grommet main body portion102to the through hole131of the dash panel130in a state of penetrating a wire bundle W at an inner portion thereof. Further, the grommet101is integrally provided with the long tube103, and therefore, the wire bundle W at inside of the tube103can be fixed to a vehicle body along with the tube103by attaching a strap110at a pertinent position of the tube103. Fixing portions by the straps110are provided at two portions of a first fixing portion K1and a second fixing portion K2.

The tube103the principal length portion of which is formed in the shape of the bellows is provided with a straight strap winding portion105which is not provided with a mountain portion104aand a valley portion104bas in the bellows portion, and on an outer peripheral face of the strap winding portion105, there is provided a projected portion107in an annular shape (further specifically, ring-like shape) for floating up both end edges110ain a width direction of the strap110from an outer peripheral face of the tube103(further in details, an outer peripheral face of the strap winding portion105).

In all example ofFIG. 4A,FIG. 4BandFIG. 5, a plurality of (2 pieces in the example ofFIG. 4A,FIG. 4BandFIG. 5) of the projected portions107in the annular shape are provided at an interval therebetween in an axis line direction of the tube103. The projected portions107in the annular shape in this case may be formed as a projected portion107aover an entire periphery thereof as shown byFIG. 5, or may be formed as an alignment of a number of projected portion107baligned at intervals in a peripheral direction.

Further, in a side direction of the projected portion107in the annular shape at the outer peripheral face of the tube103is provided with a rib108having an outer diameter larger than an outer diameter of the projected portion107in the annular shape for preventing the strap110from moving by a predetermined amount or more.

When the strap110is wound to fix to the outer periphery of the tube103of the grommet101, as shown byFIG. 4B, by winding to fasten the strap110above a top portion of the projected portion107in the annular shape along the projected portion107in the annular shape, the both end edges110ain a width direction of the strap110are held in a state of being floated up from the outer periphery of the tube103.

When the both end edges10ain the width direction of the strap110are fastened in the state of being floated up from the outer peripheral face of the tube103in this way, the both end edges110aof the strap110can be prevented from strongly interfering with the outer peripheral face of the tube103. Therefore, the outer peripheral face of the tube103can be prevented from being damaged or a crack is generated at the outer peripheral face as less as possible.

Further, when the projected portion107in the annular shape is provided at the position of winding the strap103, there is also achieved an advantage that the position of winding the strap110is made to be easy to be confirmed by optical observation.

Further, although depending on a state of use, there is a case in which a position of the strap110is shifted, since the rib108having the diameter larger than the outer diameter of the projected portion107in the annular shape is provided in the side direction of the projected portion107in the annular shape, the strap can always be held at a correct winding position.

Further, the invention is not limited to the above-described embodiment but can pertinently be modified, improved or the like. Further, materials, shapes, dimensions, numbers, arranging portions of respective constituent elements in the embodiment are arbitrary and not limited so far as the invention can be achieved.

Further, the invention is not limited to the above-described embodiments but can pertinently be modified, improved or the like. Further, materials, shapes, dimensions, numbers, arranging portions and the like of respective constituent elements in the above-described embodiment are arbitrary and not limited so far as the invention can be achieved.

According to the above-described first embodiment, there is shown a case of narrowing the inner diameter of the tube3by fastening the strap10for fixing to the outer periphery of the tube3. However, as shown byFIG. 3, a grommet1′ of a mode of narrowing an inner diameter of a tube3′ may be constituted by projecting a plurality of ribs5on an inner peripheral face of the tube3′ (further, at least one of the rib5may be provided). When constituted in this way, by only passing the wire harness W into the tube3′, water cut-off effect by narrowing the inner diameter can be achieved.

Further, although according to the first embodiment, there is shown the case of using the strap10for fastening the outer periphery of the tube3in order to narrow the inner diameter of the tube3, so far as a inner capable of narrowing the inner diameter of the tube3is used, a strap or an adhering tape may be used.

Further, in the second embodiment, a number of pieces, a sectional shape and the like of the projected portion107in the annular shape can arbitrarily be selected.