JP5488299B2 - Grommet water stop structure manufacturing method and grommet water stop structure - Google Patents

Description

  The present invention is formed in a panel that divides a flooded area and a non-flooded area (for example, a vehicle body panel that divides a flooded area such as an engine room and a non-flooded area in a vehicle interior in a vehicle such as an automobile). The present invention relates to a water stop technology for a grommet attached to a wire harness that penetrates a through hole.

  When a wire harness (W / H) in which a large number of electric wires are bundled is inserted into a panel (for example, a vehicle body panel) that divides a flooded region and a non-water-immersed region, rubber is inserted into a through hole formed in the vehicle body panel. A grommet formed of a water-stopping material such as the like is mounted, and the wire harness is inserted into the vehicle body panel through the inside of the grommet.

  The grommet generally includes a vehicle body mounting portion having an enlarged diameter and a cylindrical electric wire insertion portion continuous with the reduced diameter end thereof. When the vehicle body mounting portion is locked to the inner peripheral edge of the through hole formed in the vehicle body panel, the space between the through hole and the grommet is stopped (waterproof). On the other hand, the water stop (waterproofing) in the grommet is realized by inserting the wire harness in close contact with the inner wall of the wire insertion portion. However, it is not possible to stop water intrusion from the gap between the electric wire groups or the slight gap between the inner wall of the electric wire insertion portion of the grommet and the electric wire group simply by bringing the inner wall of the electric wire insertion portion into close contact with the wire harness. Thus, conventionally, various techniques for stopping the gap have been proposed.

  For example, Patent Document 1 proposes a technique for sealing a gap between electric wires using a spacer as a conventional technique. That is, according to the technique described here, a spacer made of a resin molded product is arranged in a direction orthogonal to the insertion direction of the wire harness, and the electric wire group is expanded by the spacer to form a gap between the electric wires. Then, the wire harness attached with the spacer is inserted into the grommet, and the gap between the electric wires formed by the spacer is filled with a sealing agent to seal the gap.

  Further, for example, Patent Document 1 proposes a technique for sealing gaps between electric wires using a water stop material formed by pressing and hardening a thermosetting resin powder. That is, according to the technique described in Patent Document 1, a water-stopping agent formed by pressing and hardening a thermosetting resin powder is placed in a wire group of a wire harness, and the wire harness on which the water-stopping agent is placed is inserted into a grommet. To do. Then, the grommet is heated at a temperature at which the thermosetting resin powder melts to melt the water stop material, thereby filling the gap between the electric wire groups with the water stop agent and sealing the gap.

JP 2009-136113 A

  In each of the conventional technologies, although a certain water-stopping effect can be obtained, it is difficult to say that a complete water-stopping performance can be realized, and in particular, a slight gap between the inner wall of the grommet wire insertion part and the wire group. It was difficult to prevent flooding.

  The present invention has been made in view of the above problems, and has a grommet water stop structure with high water stop performance that can prevent water from entering through a slight gap between the inner wall of the wire insertion portion and the wire group. It aims to provide technology that can be realized.

  1st aspect of this invention is a manufacturing method of the water stop structure of a grommet attached to the wire harness which penetrates the through-hole formed in the vehicle body panel which partitions the inside and outside of a flooded area | region, Comprising: a) By heating A solid filler having the property of being melted and fluidized and hardened by cooling is a partition plate in which a thin constricted portion is formed in the middle and a thick head is formed at the end of the constricted portion. In the wire group of the grommet mounting region in the wire harness formed by concentrating the wire group, a molding filler molded into a shape projecting radially from the part is formed in the wire group, and the central portion is placed in the wire group. A step of placing the partition plate between the wires of the wire group and disposing the head in a state of projecting outside the wire group; and b) the molded filler in the wire group. Arranged A step of externally fitting the grommet to the wire harness; and c) heating the grommet in which the wire harness is inserted so as to melt the constricted portion of the partition plate so that the head portion is attached to the partition plate. Separating from the base, melting the separated head, circulating the fluidized filler around the wire group, and melting the base of the partition plate inserted between the wires to fluidize And impregnating the filled filler into the gaps between the electric wire groups.

  The grommet water stop structure manufacturing method according to the second aspect is the grommet water stop structure manufacturing method according to the first aspect, wherein the plurality of partition plates become thinner toward the tip. A base formed in a shape, and the head is formed at a tip of the base.

  The manufacturing method of the grommet water-stopping structure according to the third aspect is the manufacturing method of the grommet water-stopping structure according to the first or second, wherein the filler is made of an EVA resin composition.

  According to a fourth aspect of the present invention, there is provided a grommet water stop structure, and the grommet water stop structure manufacturing method according to any one of the first to third aspects.

  According to the first aspect, the grommet in which the wire harness is inserted is heated to melt the head portion of the molded filler so that the fluidized filler circulates around the wire group and is inserted between the wires. The base of the partition plate of the molded filler is melted, and the fluidized filler is permeated into the gap between the electric wire groups. According to this configuration, since both the gap between the electric wires and the gap between the electric wire group and the grommet inner wall are appropriately stopped, the grommet can be reliably stopped.

  According to the 2nd aspect, in the partition plate of a shaping | molding filler, a head is formed in the front-end | tip of the base formed in the taper shape which becomes thin as it goes to a front-end | tip. According to this configuration, when the grommet in which the wire harness is inserted is heated, the joint portion between the base and the head can be quickly melted. Therefore, the filler can be reliably circulated around the electric wire group, and the gap between the electric wire group and the grommet inner wall can be reliably stopped.

It is sectional drawing of the grommet in the state where the wire harness is not inserted. It is sectional drawing of the grommet in the state by which the wire harness was inserted and the water was stopped. It is a perspective view of a molding filler. It is a figure which shows the molding filler arrange | positioned in the electric wire group. It is a perspective view which shows the mode of the cross section of the electric wire group by which the expanded grommet was externally fitted. It is a figure which shows typically the mode of the cross section of the electric wire group in the initial stage of a heating. It is a figure which shows typically the mode of the cross section of the electric wire group in the stage which heating advanced. It is a figure which shows the state by which the foam sheet was wound by the grommet attachment area | region of the wire harness in which the shaping | molding filler is arrange | positioned.

<1. Grommet>
The configuration of the grommet 1 will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the grommet 1 in a state where the wire harness 900 is not inserted, and FIG. 2 is a cross-sectional view of the grommet 1 in a state where the wire harness 900 is inserted and water is stopped.

  The grommet 1 is composed of a resilient water-stopping member such as an elastomer (for example, a thermosetting elastomer). The grommet 1 includes a vehicle body mounting portion 11 having a circular cross section that increases in diameter toward the tip, and a cylindrical electric wire insertion portion 12 that is continuous with the reduced diameter end of the vehicle body mounting portion 11.

  A locking groove 111 is formed in the outer peripheral portion on the side of the enlarged diameter end of the vehicle body mounting portion 11 along the circumferential direction, and the locking groove 111 is locked to the periphery of the through hole formed in the vehicle body panel. Thus, the grommet 1 is attached to the vehicle body panel.

  The inner wall of the electric wire insertion portion 12 is in close contact with the outer periphery of a group of electric wires 9 (electric wire group 90) constituting the wire harness (W / H) 900. That is, the inner diameter of the wire insertion portion 12 is smaller than the outer diameter of the wire harness 900 (that is, the diameter of the circumscribed circle of the bundled electric wire group 90), and the wire harness 900 inserted into the inner portion is elastically attached to the outer peripheral side. Tighten from. The region of the wire harness 900 to which the electric wire insertion portion 12 is in close contact (that is, the attachment region of the grommet 1 in the wire harness 900) is hereinafter referred to as “grommet attachment region T”.

  All or at least a part of the grommet attachment region T of the wire harness 900 is a water stop region, and the water stop region is filled with the filler 2. In the example of FIG. 2, the entire grommet attachment area T is a water stop area, and the entire grommet attachment area T is filled with the filler 2. According to the water stop structure manufactured by the method described below, the gap between the wires of the wire group 90 in the water stop region and the gap between the wire group 90 and the inner wall of the wire insertion portion 12 in the water stop region. A reliable water stop structure in which the filler 2 is reliably filled is realized.

<2. Molding filler 20>
The molding filler 20 is used for manufacturing the water stop structure of the grommet 1 according to the embodiment of the present invention. The configuration of the molding filler 20 will be described with reference to FIG. FIG. 3 is a perspective view of the molding filler 20.

  The molded filler 20 is obtained by molding a solid filler 2 having a property of being melted by heating and having fluidity and being cured by cooling into a predetermined shape. As the filler 2, for example, an EVA resin composition (for example, ethylene / propylene / non-conjugated diene copolymer rubber (EPPM), thermoplastic resin powder (for example, epoxy resin powder), or the like can be used. In the case of using a thermoplastic resin powder as the filler 2, the powder is not a powder obtained after the thermoplastic resin is melted at a melting temperature and then solidified to form a powder. It is necessary to use a powder of curable resin.

  Next, the shape of the molding filler 20 will be described. The molding filler 20 has a cylindrical core portion 21 and a partition plate 22 that protrudes radially from the core portion 21 at a certain angle in the circumferential direction. In FIG. 3, eight partition plates 22 are formed, but the number of partition plates 22 is not limited to this. As will be described later, the space between the adjacent partition plates 22 and around the core portion 21 functions as an electric wire housing space V for housing the electric wires 9.

  The partition plate 22 is formed with a thin portion (a portion narrowed and narrowed in a side view) 223 (hereinafter referred to as a “constricted portion”) 223 in the middle, and a thick portion (a large-diameter portion in a side view) in front of the constricted portion 223. ) (Hereinafter referred to as “head”) 222 is formed. Specifically, the partition plate 22 has a shape including a base portion 221 formed in a tapered plate shape that becomes thinner toward the tip end, and a head portion 222 formed at the tip end of the base portion 221. A constricted portion 223 is formed at the joint between the head 221 and the head 222. The head 222 has an oval cross-sectional shape that is orthogonal to the wire insertion direction x.

  In addition, the length (long width) along the longitudinal direction of the molding filler 20 is the same as or shorter than the width of the water stop region. Further, the outer diameter of the molding filler 20 is formed to be slightly larger than the inner diameter of the wire insertion part 12 of the grommet 1.

<3. Manufacturing method of water-stop structure of grommet 1>
A series of steps relating to a method for manufacturing a water stop structure of the grommet 1 using the molded filler 20 will be described.

<First step>
First, the molding filler 20 is arrange | positioned in the electric wire group 90 of the grommet attachment area | region T of the wire harness 900 (1st process). The first step will be specifically described with reference to FIG. FIG. 4 is a view showing the molding filler 20 arranged in the electric wire group 90. However, in FIG. 4, in order to show the state of the molded filler 20 disposed inside the electric wire group 90, the electric wire group 90 is shown cut at the end position of the filler enclosure 20.

  The first step is performed by the operator performing the following operation. That is, the operator pushes and expands the wire group 90 in the grommet mounting region T of the wire harness 900 so that the longitudinal direction of the molded filler 20 extends along the wire insertion direction x from the direction orthogonal to the wire insertion direction x. In a posture, the molding filler 20 is put into the electric wire group 90. Here, the operator positions the core portion 21 so as to come to the center portion of the wire group 90 and positions the electric wires 9 substantially uniformly on the entire outer periphery of the molding filler 20, and in this state, the electric wires 9 are molded and filled. The agent 20 is dispersed and pushed into the gaps between the partition plates 22 and inserted into the electric wire accommodating spaces V evenly. It is preferable that the plurality of electric wires 9 constituting the electric wire group 90 are dispersed and accommodated in the plurality of electric wire accommodation spaces V as evenly as possible.

  Then, the molding filler 20 is formed in the grommet attachment region T of the wire harness 900 in the state shown in FIG. 4 (that is, the core portion 21 is located at the center of the wire group 90 and is partitioned between the wires of the wire group 90. The plate 22 is inserted, and the head 222 is arranged in a state of protruding to the outside of the electric wire group 90). By arranging the molding filler 20 in such a state, the plurality of electric wires 9 constituting the electric wire group 90 are accommodated in the plurality of electric wire accommodation spaces V formed in the molding filler 20.

<Second step>
Subsequently, the grommet 1 is externally fitted to the grommet attachment region T of the wire harness 900 (second step). The second step will be specifically described with reference to FIG. FIG. 5 is a perspective view showing a cross-sectional state of the wire group 90 in which the expanded grommet 1 is fitted.

  The second step is performed by the operator performing the following operation. That is, the operator increases the diameter of the grommet 1 using an expansion machine or the like, and inserts the wire harness 900 into the expanded grommet 1. And the grommet attachment area | region T of the wire harness 900 is located in the electric wire insertion part 12 of the grommet 1. FIG. However, the molding filler 20 is disposed in the wire group 90 in the grommet attachment region T. That is, the region of the wire group 90 where the molding filler 20 is disposed is placed in the wire insertion portion 12 of the expanded grommet 1.

<Third step>
Subsequently, the grommet 1 in which the wire harness 900 is inserted is heated to a temperature at which the molding filler 20 is melted (third step). The third step will be specifically described with reference to FIGS. FIG. 6 is a diagram schematically illustrating a cross-sectional state of the wire group 90 in the initial stage of heating. FIG. 7 is a diagram schematically showing the state of the cross section of the wire group 90 at the stage where heating has progressed.

  The third step is performed by the operator performing the following operation. That is, the operator inserts the wire insertion portion 12 of the grommet 1 in which the wire harness 900 is inserted into the cylindrical heater, and heats the wire insertion portion 12 of the grommet 1 with the heater.

  When the wire insertion part 12 of the grommet 1 is heated, the molding filler 20 inside the wire insertion part 12 is melted. As described above, the partition plate 22 of the molding filler 20 has a shape in which the large-diameter head 222 is formed at the tip of the constricted portion 223. Therefore, when heating of the grommet 1 is started, a constricted portion 223 that is a joint between the base portion 221 and the head portion 222 is first melted. Then, the head portion 222 is separated from the base portion 221 and travels around the wire group 90 while melting, whereby the fluidized filler 2 travels around the wire group 90 (shown in FIG. 6). State). On the other hand, the base portion 221 starts to dissolve in order from the tip, and the fluidized filler 2 penetrates into the gaps between the wires of the wire group 90. Therefore, as the heating proceeds, the filler 2 is filled in the gaps between the wires of the wire group 90 and the periphery of the wire group 90.

  At the stage where the molding filler 20 is dissolved by about half, the operator releases the diameter expansion of the grommet 1 by the expansion machine. Then, the diameter of the expanded grommet 1 is reduced to the original state by the elastic recovery force of the wire insertion portion 12. Then, the inner wall of the electric wire insertion part 12 contacts the outer periphery of the electric wire group 90, and the electric wire group 90 is fastened by an elastic recovery force. Since the periphery of the electric wire group 90 is wrapped in the molten filler 2, the gap between the outer periphery of the electric wire group 90 and the inner wall of the electric wire insertion portion 12 is completely filled in the filler 2 (FIG. 7).

  The molten filler 2 is cured after a predetermined time has passed by natural cooling. As a result, the gap between the electric wires of the electric wire group 90 and the gap between the electric wire group 90 and the inner wall of the grommet 1 are stopped by the filler 2 filled therein.

<4. Effect>
According to the above-described embodiment, the grommet 1 in which the wire harness 900 is inserted is heated to melt the head portion 222 of the molded filler 20, and the fluidized filler 2 is circulated around the wire group 90. At the same time, the partition plate 22 of the molding filler 20 inserted into the wire group 90 is melted, and the fluidized filler 2 is permeated into the gaps between the wires of the wire group 90. According to this configuration, since both the gap between the wires of the wire group 90 and the gap between the wire group 90 and the inner wall of the grommet are appropriately stopped, the grommet 1 can be reliably stopped.

  Moreover, according to said embodiment, the head 222 is formed in the front-end | tip of the base 221 formed in the taper shape which becomes thin in the partition plate 22 of the shaping | molding filler 20 as it goes to a front-end | tip. According to this configuration, when the grommet 1 in which the wire harness 900 is inserted is heated, the joint portion between the base portion 211 and the head portion 222 can be quickly melted. Therefore, the filler 2 can be reliably circulated around the electric wire group 90, and the gap between the electric wire group 90 and the grommet inner wall can be reliably stopped.

<5. Modification>
In the above embodiment, even if the diameter of the cross section of the head 222 is formed to be larger than the average separation distance between the electric wires 9 in the state of being accommodated in the electric wire accommodating space V. Good. If formed in this way, when the head 222 is separated from the base 221 by heating the molding filler 20, the head 222 remains between the wire 9 and the wire 9 accommodated in the wire housing space V. It is possible to reliably avoid the situation of falling and to make the head 222 circulate around the wire group 90 with certainty.

  In the above embodiment, heating of the grommet 1 is started before releasing the diameter of the grommet 1. However, the heating of the grommet 1 may be started after releasing the diameter of the grommet 1. Good. Also in this case, when heating is started, the constricted portion 223 of the partition plate 22 is first melted, whereby the head 222 is separated from the base 221, and the separated head 222 exerts pressure at which the grommet 1 tightens from the outer periphery. It will be received and will circulate evenly around the wire group 90. In this case, when the diameter of the grommet 1 is released, the tip of the partition plate 22 of the molding filler 20 may be broken down. For example, the constricted portion 223 may be broken and the head 222 may be separated from the base 221. Here, the molding filler 20 disposed in the grommet attachment region T is in a state in which the tip of the partition plate 22 protrudes to the outside of the wire group 90 (see FIGS. 4 and 5). The tip end portion of the partition plate 22 that is broken when the diameter is released falls down so as to cover the periphery of the wire group 90. Therefore, when heating of the grommet 1 is started, a broken portion of the partition plate 22 that falls down so as to cover the wire group 90 (for example, the head 222 separated from the base portion 221) melts, whereby the wire group 90 The fluidized filler 2 circulates around.

  Thus, even if it is the structure which starts the heating of the grommet 1 after canceling the diameter expansion of the grommet 1, the filler 2 is reliably filled in the clearance gap between the electric wires of the electric wire group 90, and the circumference | surroundings of the electric wire group 90. Can do. As a result, the grommet 1 can be reliably stopped.

  In the above embodiment, after the first step and before the second step (that is, after the molding filler 20 is disposed in the wire group 90 in the grommet mounting region T of the wire harness 900). Before the grommet 1 is externally fitted to the grommet mounting region T of the wire harness 900, a sheet made of foam around the grommet mounting region T of the wire harness 900 in which the molding filler 20 is disposed ( It is good also as a structure which winds the foam sheet 3).

  FIG. 8 is a view showing a state in which the foam sheet 3 is wound around the grommet attachment region of the wire harness 900 in which the molding filler 20 is disposed. However, in FIG. 8, the electric wire group 90 is shown cut at the end position of the filler enclosure 20.

  As the foam sheet 3, for example, a foam sheet having a semi-closed cell structure such as EPDM (ethylene-propylene-diene rubber) can be used.

  The step of winding the foam sheet 3 is performed by the operator performing, for example, the following operation. That is, the worker first applies silicon to the foam sheet 3. Subsequently, the foamed sheet 3 coated with silicon is wound around the grommet attachment region T of the wire harness 900 in which the molding filler 20 is disposed. Then, the foam sheet 3 is fixed by the tape 31. However, the method of winding the foam sheet 3 is not necessarily the above.

  The foam sheet 3 wound around the grommet attachment region T of the wire harness 900 in which the molding filler 20 is disposed is formed by the wire group 90 by the elastic recovery force of the wire insertion portion 12 when the expansion of the grommet 1 is released. It is press-contacted around. That is, the periphery of the wire group 90 (specifically, the periphery of the grommet attachment region T) is sealed by the foam sheet 3. Thereby, it is possible to prevent the filler 2 melted in the heating step from flowing out of the grommet attachment region T.

  In addition, when winding the foam sheet 3, the foam sheet 3 should be lightly wound without being tightly tightened so that the tip of the partition plate 22 of the molding filler 20 disposed in the wire harness 900 is not broken. Is preferred. However, since the foamed sheet 3 is made of a foam, even if the foamed sheet 3 is loosely wound, when the expansion of the grommet 1 is released, the foamed sheet 3 becomes a group of wires due to the elastic recovery force of the wire insertion portion 12. The foam sheet 3 is securely pressed around the wire group 90 (specifically, around the grommet mounting region T). That is, even if the foamed sheet 3 is loosely wound, there is no problem with the sealing property, and the filler 2 can be prevented from flowing out of the grommet attachment region T.

DESCRIPTION OF SYMBOLS 1 Grommet 2 Filler 9 Electric wire 20 Molding filler 21 Core part 22 Partition plate 221 Base part 222 Head part 223 Neck part 90 Electric wire group 900 Wire harness

Claims (4)

A method for producing a water stop structure for a grommet to be attached to a wire harness that penetrates a through hole formed in a vehicle body panel that partitions the inside and outside of a flooded area,
a) A solid filler having the property of being melted by heating and having fluidity and being cured by cooling, a thin constricted portion formed in the middle, and a thick head formed at the tip of the constricted portion In the wire group in the attachment area of the grommet in the wire harness formed by concentrating the wire group, the center filler is molded into a shape in which a plate is radially projected from the center portion. A step of placing the partition plate between the wires of the wire group and placing the head in a state of projecting to the outside of the wire group while being positioned at the center of the wire group;
b) externally fitting the grommet to the wire harness in which the molding filler is disposed in the wire group;
c) heating the grommet in which the wire harness is inserted, melting the constricted portion of the partition plate to separate the head from the base of the partition plate, and melting the separated head And circulating the fluidized filler around the electric wire group and melting the base portion of the partition plate inserted between the electric wires to permeate the fluidized filler into the gap between the electric wire groups. When,
The manufacturing method of the water stop structure of a grommet provided with this. It is a manufacturing method of the water stop structure of a grommet according to claim 1,
The plurality of partition plates are
A base formed in a tapered shape that becomes thinner as it goes to the tip,
With
The manufacturing method of the water stop structure of a grommet, wherein the head is formed at a tip of the base. It is a manufacturing method of the water stop structure of a grommet according to claim 1 or 2,
The method for producing a water stop structure for a grommet, wherein the filler comprises an EVA resin composition.   A water stop structure for a grommet manufactured by the manufacturing method according to claim 1.

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