Patent Application
20070209821
The present invention relates to a waterproof structure of an electric wire connecting part and a waterproof method. More particularly the present invention is intended to waterproof the electric wire connecting part by filling silicone in the electric wire connecting part at which cores of electric wires exposed by peeling insulating covers thereof are connected to each other.
Heretofore, in connecting a plurality electric wires to each other in a wire harness to be mounted in a car, an insulating cover of each electric wire is peeled to expose each core thereof, and exposed portions of the cores are connected to each other by welding, soldering or with a pressure terminal to form a connecting part. When the connecting part is covered with water, the cores and the pressure terminal are corroded. Thus in the wire harness disposed at an engine room side which is a region into which water penetrates, a waterproof structure is formed at the connecting part thereof.
As a waterproof structure having the above-described construction, as disclosed in Japanese Patent Application Laid-Open No.4-334917, the present applicant proposed a waterproof structure of the connecting part shown in
When the cores 2 are connected to each other with the pressure terminal 3 as described above, the number of electric wires which can be connected is not large. Thus even though the silicone 6 has a high viscosity, waterproofness can be accomplished by filling the silicone 6 between the cores 2.
But in forming the connecting part by connecting a large number of the cores to each other by ultrasonic welding, resistance welding, soldering or the like, the silicone 6 cannot be filled in the entire spaces between the cores 2 when the silicone 6 has a high viscosity. Therefore to fill the silicone 6 in a large number of spaces between the cores 2, it is necessary to decrease the viscosity of the silicone 6. When the silicone 6 having a low viscosity is applied to and filled in the spaces between the cores 2, the above-described waterproof structure has a problem that the silicone 6 drops or oozes from the films 5, 7 in wrapping the films 5, 7 around the connecting part. No problem occurs if the oozed silicone 6 solidifies. But leaving the silicone 6 until it solidifies makes the work efficiency low.
Patent document 1: Japanese Patent Application Laid-Open No.4-334917
The present invention has been made in view of the above-described problems. Thus it is an object of the present invention to efficiently form a waterproof structure which securely waterproofs an electric wire connecting part by filling silicone between cores of the electric wire connecting part and prevents the silicone from dropping during a work and oozing after the work finishes.
To solve the above-described problems, the present invention provides a waterproof structure of an electric wire connecting part in which insulating covers of electric wires are peeled; and exposed cores are connected to each other by welding, soldering or with a pressure terminal to form a connecting part; a foamed sheet impregnated with silicone is wrapped around the connecting part; and the silicone is filled in clearances between the connected cores to waterproof the electric wire connecting part.
In the above-described construction, the connecting part of the electric wires is waterproofed by wrapping the foamed sheet impregnated with the silicone around the connecting part of the electric wires and filling the silicone in the clearances between the connected cores. In addition, the foamed sheet is capable of re-absorbing the silicone which drops or oozes therefrom in wrapping the foamed sheet around the connecting part. Therefore it is possible to efficiently perform a work of wrapping the foamed sheet around the electric wires by preventing the drop or oozing of the silicone.
Further because the foamed sheet prevents the drop or oozing of the silicone, it is possible to use the silicone having a low viscosity as a waterproof agent and thus fill the silicone in a large number of clearances between the cores by securely permeating the silicone thereinto.
Considering that the silicone permeates into the cores of the electric wires and is absorbed by the foamed sheet, it is preferable that the viscosity of the silicone is set to not more than 5 Pa·S.
In the connecting part of the cores covered with the foamed sheet, an adhesive tape is wrapped around a peripheral surface of the foamed sheet.
Thereby the foamed sheet is held, with the foamed sheet wrapped around the connecting part of the electric wires.
It is possible that the connecting part of the cores covered with the foamed sheet is closely fitted inside a pair of semicircular annular members coupled to each other through a thin hinge portion at one end thereof and that other ends of the semicircular annular members are locked to each other.
In the above-described construction, the connecting part of the electric wires can be easily waterproofed by wrapping the foamed sheet impregnated with the silicone around the connecting part of the electric wires, locking a pair of the semicircular annular members to each other, and mounting a sheath on the connecting part of the electric wires.
Silicone which has oozed from the foamed sheet forms a silicone-filled portion at a contact portion between the connecting part of the cores and the foamed sheet.
In the above-described construction, the silicone-filled portion formed by the oozing of the silicone from the foamed sheet at the contact portion between the connecting part of the cores and the foamed sheet is capable of waterproofing the connecting part of the cores. In the construction in which the silicone is not permeated into the peripheral side, of the foamed sheet, which does not contact the connecting part of the cores, the peripheral side of the foamed sheet efficiently re-absorbs the silicone which drops or oozes therefrom when the foamed sheet is wrapped around the connecting part, thus preventing the drop and oozing of the silicone therefrom.
It is preferable that the foamed sheet consists of an interconnecting cellular foamed material.
In this construction, the silicone which has sufficiently permeated into the foamed sheet oozes to form the silicone-filled portion. In addition, it is possible to efficiently absorb the silicone that has oozed outside.
It is preferable that a concavity and a convexity fitting in each other are formed at opposite sides of a surface of the foamed sheet in a direction in which the foamed sheet is wrapped around the connecting part of the cores.
Owing to the above-described configuration of the foamed sheet, when the adhesive tape and the foamed sheet are folded at the position where the electric wires are disposed, with the foamed sheet impregnated with the silicone disposed on the adhesive tape and with the connecting part of the cores disposed on the foamed sheet, the surface of the concavity and that of the convexity fitted in the concavity adhere to the adhesive tape. Thus when the concavity and the convexity are further folded and wrapped around the connecting part of the cores, the foamed sheet does not shift because both surfaces of the concavity and that of the convexity are adhered to the adhesive tape. Therefore it is easy to accomplish a wrapping work which is performed by re-folding the concavity and the convexity.
The foamed sheet is not overlapped at the position where the foamed sheet is re-folded. Because only one sheet of the foamed sheet is folded, a large force is unnecessary in folding it.
It is possible that the foamed sheet which is rectangular is disposed, wound, and portions thereof are laminated on each other, with the foamed sheet inclined with respect to an axial direction of the connecting part of the cores and that the rectangular adhesive tape disposed in parallel with the axial direction of the connecting part of the cores is wrapped around a peripheral surface of the foamed sheet.
In the above-described construction, when the adhesive tape and the foamed sheet are folded at the position where the electric wires are disposed, portions of the foamed sheet overlap on each other, and portions of the adhesive tape are adhered to each other at both sides of the foamed sheet. Thus when the overlapped side is further folded and wound, the foamed sheet does not shift. Therefore it is easy to accomplish a wrapping work which is performed by re-folding the overlapped side.
The foamed sheet is disposed by inclining it with respect to the axial direction of the connecting part, at the position where the foamed sheet is folded and overlapped, the foamed sheet is short in the axial length of the connecting part. Therefore a large force is not required to fold the foamed sheet.
The present invention provides a method of waterproofing an electric wire connecting part including the steps of forming a connecting part of cores by peeling insulating covers of a plurality of electric wires and connecting exposed cores to each other by welding, soldering or with a pressure terminal; and
disposing a foamed sheet impregnated with silicone on an adhesive tape, disposing the connecting part of the cores on the foamed sheet, folding the adhesive tape and the foamed sheet and overlapping the foamed sheet on the adhesive tape at a position where the electric wires are disposed, and folding and winding an overlapped side.
Particularly, a concavity and a convexity fitting in each other are formed at opposite sides of a surface of the foamed sheet in a direction in which the foamed sheet is wrapped around the connecting part of the cores or the foamed sheet which is rectangular is disposed, with the foamed sheet inclined with respect to the axial direction of the connecting part of the cores. Thereby as described above, the foamed sheet and the adhesive sheet can be re-folded easily at the position where the foamed sheet and the adhesive sheet are folded and overlapped on each other.
As described above, according to the present invention, waterproofing is performed by wrapping the foamed sheet impregnated with the silicone around the connecting part of the electric wires and filling the silicone in the clearances between the cores. In addition, the foamed sheet is capable of absorbing the silicone which has dropped or oozed therefrom. Therefore it is unnecessary to leave the silicone until it solidifies and possible to efficiently perform a work of wrapping the foamed sheet around the electric wires.
Further because the foamed sheet prevents the drop or oozing of the silicone, it is possible to use the silicone having a low viscosity as a waterproof agent and thus fill the silicone in a large number of clearances between the cores by securely allowing the silicone to permeate thereinto.
FIGS. 13(A), (B), and (C) show a method of forming a waterproof structure of the third embodiment.
FIGS. 14(A) and (B) show a conventional art.
Explanation of reference symbols and numerals
The embodiments of the present invention will be described below with reference to the drawings.
As shown in
The foamed sheet 15 is composed of an interconnecting cellular foamed material. The silicone 14 is applied to the center of the foamed sheet 15 to impregnate the foamed sheet 15 with the silicone 14. On the other hand, the silicone 14 is not applied to the peripheral side of the foamed sheet 15.
The viscosity of the silicone 14 is set to a low viscosity of 5 Pa·S. The application amount of the silicone 14 is shown by (1−n)×(a×h)×s(g) (n is the density (g/cm3) of the foamed sheet, a is the surface area (cm2) of the foamed sheet, h is the thickness (cm) of the foamed sheet, and s is the specific gravity of the silicone). In the first embodiment, n=0.064(g/cm3), a=9(cm2), h=0.2(cm), and s=l.01(g). The application amount of the silicone 14 is set to 1.7 g.
The method of forming the waterproof structure 10 of the connecting part 13 is described below.
Initially as shown in
As shown in
The connecting part 13 of the electric wires w1, w2 is placed at the central position of the foamed sheet 15.
Thereafter as shown in
Finally as shown in
In the above-described construction, because the silicone 14 having a low viscosity is used to waterproof the connecting part 13 formed between the electric wires w1 and w2, the silicone 14 can be penetrated between the cores 12 of the electric wires w1, w2. Thus the waterproofness can be secured. Further the silicone 14 having a low viscosity is permeated into the foamed sheet 15. Thus when the foamed sheet 15 is wrapped around the electric wires w1, w2, the silicone 14 oozes from the foamed sheet 15 and can be permeated between the cores 12. The silicone 14 oozing from the foamed sheet 15 can be re-absorbed by the foamed sheet 15. Therefore it is possible to efficiently perform a work of wrapping the foamed sheet 15 around the electric wires w1, w2.
Because the foamed sheet 15 is capable of absorbing the silicone oozing from the foamed sheet 15, it is only necessary to wrap the foamed sheet 15 to the tip portion of the insulating cover 11 continuous with the exposed cores 12. Thus it is possible to decrease the wrapping range of the foamed sheet 15. Thereby the electric wires are not made large.
Although in the first embodiment, two electric wires are spliced to each other, the waterproof structure of the first embodiment may be formed for a connection part at which not less than three electric wires are spliced to each other.
Further the waterproof structure of the first embodiment may be formed for not only the connecting part formed at the central position of the electric wires, but also for the connecting part formed at the terminal of electric wires.
The connecting part of the cores may be formed by connecting the cores to each other not only by welding but also by soldering or with a pressure terminal.
The electric wires w1, w2 having the connecting part 13 are placed on diagonal lines of the foamed sheet 15. Similarly to the first embodiment, as shown in
In the above-described construction, because an axial length L3 of the connecting part on the broken line 1 along which the-foamed sheet 15 is folded by using the tape-wrapping machine is short, the foamed sheet 15 can be folded at a smaller torque than the torque in the first embodiment. Because an adhesive force is increased by increasing an area of contact S between the adhesive tape 16 at both sides of the folded foamed sheet 15, the foamed sheet 15 does not shift in the axial direction of the connecting part. Thus the foamed sheet 15 can be easily wrapped around the electric wires w1, w2.
The concavity 15a of the foamed sheet 15 and the convexity 15b thereof are adhered to the adhesive tape 16, with the concavity 15a and the convexity 15b opposed to each other in an electric wires-wrapping direction. The foamed sheet 15 and the adhesive tape 16 are folded at a position where the electric wires w1, w2 are disposed, with the electric wires w1, w2 placed at positions where the electric wires w1, w2 pass through the center of the foamed sheet 15. As a result, a state shown in
In forming the waterproof structure 10′, a jig 30 is used. As shown in
The method of forming the waterproof structure 10′ is described below.
Initially as shown in
Thereafter as shown in
Finally as shown in
By carrying out the above-described method, the waterproof structure 10′ can be formed on the connecting part 13.
In the above-described method, the electric wires are merely pressed into the jig. Therefore without skill, everybody can easily form the waterproof structure 10′. Further the method eliminates the need for using the tape-wrapping machine. Thus it is possible to reduce the cost of forming the waterproof structure 10′.
Further by visually checking whether a pair of the semicircular annular members 20a has been locked to each other, it is possible to detect whether the waterproof structure has been formed. Furthermore by forming the sheath 20 from a transparent resin, it is possible to visually check a state inside the sheath 20.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-130330 | Apr 2004 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/03746 | 3/4/2005 | WO | 10/5/2006 |
