JP3361714B2 - Method of forming a coating layer on a wire branch and a coating structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a resin coating layer covering a periphery of an electric wire branching portion in which a branching electric wire is branched and connected to each core wire of a trunk cable (main electric wire) with a sheath removed by a resin molding method. The present invention relates to a method for forming a coating layer of a wire branch portion, and more particularly, to an improvement for improving waterproofness of a resin coating layer and at the same time strengthening protection of a connection portion against external force.

[0002]

2. Description of the Related Art As a method of connecting a plurality of branch electric wires to a main cable, as shown in FIG.
The conductor insulation part 2 is formed by exposing the conductor of each core wire by shifting its position in the axial direction of the cable and peeling the insulation coating of each core wire forming the Then, a method is known in which the conductor 3 of each core wire of the conductor exposed portion 2 with the insulation coating of the branching electric wire 4 removed is crimp-connected via a dedicated crimp connector.
In this way, the electric wire branching part 5 in which the core wires of the branching electric wire 4 are connected to the exposed conductors of the core wires of the main cable 1 as it is may cause an accident such as a short circuit due to the exposed conductor parts. is there. Further, the exposed conductor portion is easily corroded by outside air or moisture, and is easily damaged by an external force.

Therefore, usually, the electric wire branch portion 5 is subjected to a covering treatment so as to cover the exposed conductor and the insulating covering portion of the trunk cable 1 before and after the exposed conductor. As such a coating method, first, as shown in FIG. 9, an insulating tape 7 is first wrapped around the electric wire branch portion 5, and then the tape-wound range 6 is set as shown in FIG. A method has been proposed in which the resin coating layer is placed in a molding die 8 and covers the area around the tape-wound area 6 by a resin molding method. In addition, a molding die used for molding is usually divided into two parts, an upper part and a lower part. In FIG. 10, only the lower mold is shown for simplification.

As described above, when the resin coating layer which covers the periphery of the electric wire branch portion 5 is formed by the resin molding method, the finished dimension (outer dimension) can be made constant, and the working process is comparatively performed. Very few. Further, by appropriately selecting the resin material used for the mold, it is possible to sufficiently enhance the mechanical strength from the viewpoint of protecting the branch portion, the waterproof performance, and the like.

[0005]

However, as shown in FIG. 10, when the tape-wound area 6 is set in the resin filling space 9 of the molding die 8 as it is, the molding is performed. The area 6 in which the mold resin filling pressure into the mold is tape-wrapped is pushed toward the bottom surface of the molding die 8 which is the lower mold, and due to the pressing force due to this filling pressure, the resin is filled in the resin filling space 9. The position of the tape-wound range 6 bends toward the bottom surface of the molding die 8. This deflection becomes more remarkable as the length (span) of the tape-wound range 6 is longer and the resin filling pressure is higher.

In an extreme case, a part of the tape-wound area 6 may be exposed on the outer surface of the resin coating layer. When the tape-wound area 6 is eccentric with respect to the resin coating layer in this way, the mechanical strength and the waterproof performance from the viewpoint of protecting the wire branch portion 5 are weak in the thin portion of the resin coating layer. . That is, when the coating process is performed by the conventional resin molding method, the position of the electric wire branch portion 5 is deviated due to the resin filling pressure in the molding die, and the mechanical strength and the waterproof performance are likely to vary. There was a problem.

Therefore, an object of the present invention is to solve the above-mentioned problems, the finished size can be made constant, and the mechanical strength, the waterproof performance, and the like from the viewpoint of protecting the wire branch portion are not uniform. It is an object of the present invention to provide a method for forming a coating layer of an electric wire branching portion, which does not occur, can exhibit a sufficient protective performance, requires a small number of working steps, and can reduce the production cost.

[0008]

The above object of the present invention is a method for forming a coating layer of a wire branch portion in which a branch wire is connected to a main wire, which is made of an insulating material provided with a plurality of projections of a predetermined length. A winding band is wound around the electric wire branch portion so that the protrusion faces outward, both ends of the winding band are tape-fixed to the main electric wire, and the electric wire branch portion in a state where the winding band is wound is molded. A method for forming a coating layer of an electric wire branching part, characterized in that the electric wire branching part is molded by molding into the electric wire branching part by positioning the protrusion by a distance apart from the inner wall of the molding mold by inserting the mold into the molding die. Achieved by In this method, the protrusion sealing adhesive may be applied after fixing the winding band to the wire branch portion.

Further, the above object of the present invention is a coating structure of an electric wire branch portion in which a branch electric wire is connected to a main electric wire, and a predetermined flexibility is imparted so that the electric wire branch portion can be wound around the electric wire branch portion. A wrapping band made of an insulating material having a projection protruding from one surface of the substrate, a fixing means for fixing the wrapping band to the main electric wire, and a thickness determined by the projection in the molding die. This is achieved by a wire branching portion covering structure having a resin coating layer that covers the entire wire branching portion including the winding band. Here, a sealing adhesive may be provided between the winding band and the resin coating layer.

According to the above method and structure, the electric wire branch portion set in the resin-filled space of the molding die is wound by the projection of the winding belt pre-wound and mounted on the branch portion.
The branch portion is prevented from being biased by the filling pressure of the resin with which the resin filling space is supported by the substantially center of the resin filling space. Further, since the wrapping band attached to the wire branch portion is buried in the resin coating layer formed by molding, extra work is not required after the attachment. Therefore, fewer work steps are required. Further, by providing a sealing adhesive between the wrapping band and the resin coating layer, this adhesive can enter a gap between the resin coating layer and the protrusion, which can be formed in the resin coating layer, to create a watertight state.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the illustrated embodiments. 1 to 7 show an embodiment of a method for forming a coating layer of an electric wire branch portion according to the present invention. FIG. 1 shows an electric wire branch portion for forming a resin coating layer by the coating layer forming method of the embodiment. Fig. 2 is an external view, Fig. 2 is an external view showing a mounting state of a winding band in the coating layer forming method of one embodiment, and Fig. 3 is a supporting structure of a wire branch portion in a molding die in the coating layer forming method of one embodiment. 6 is a perspective view showing the appearance of the resin coating layer of the electric wire branch portion formed by the coating layer forming method of one embodiment, FIG. 5 is a plan view of the winding band used in one embodiment, and FIG. 5 is a view on arrow B in FIG. 5, and FIG. 7 is a view on arrow C in FIG.

The method of forming a coating layer according to this embodiment is shown in FIG.
As shown in Fig. 5, the conductor branch portion 5 is formed by branching and connecting each core wire of the branching electric wire 4 to the conductor exposed portion 2 of each core wire in which the insulation coating of the main cable 1 is removed, The resin coating layer that covers is formed by a resin molding method. The connection between the core wire of the trunk cable 1 and the core wire of the branching electric wire 4 in the electric wire branching portion 5 is performed by crimping using a predetermined connector terminal, which is the same as the conventional case.

Further, as shown in FIG. 2, a winding band 12 is provided on the wire branch portion 5 on which the tape winding 10 is performed.
Is wrapped around and attached. Here, the electric wire branching portion 5 in which the predetermined core wires are crimp-connected to each other is provided with the tape winding 10 made of an insulating tape so that the core wires do not move carelessly and the wrapping band 12 can be held. It

As shown in FIGS. 5 to 7, the winding band 12 has a substrate 13 provided with a predetermined flexibility so that it can be wound around the electric wire branch portion 5, and a substantially constant surface on one side of the substrate 13. The projections 14 provided at intervals are integrally formed of an insulating resin. In the substrate 13 of this embodiment, V-shaped grooves 16 extending along the axial direction of the cable are formed at regular intervals so as to be easily wound around the wire branch portion 5.

The projections 14 are provided on the surface of the substrate 13 on which the V-shaped grooves 16 are provided so that when the substrate 13 is wound around the wire branch portion 5, the protrusions 14 are arranged radially around the wire branch portion 5. Is projected almost vertically. Each of the protrusions 14 is formed by molding the electric wire branch portion 5 around which the winding band 12 is wound into a molding die 8
When it is put into the resin filling space 9 inside, the tip end surface 14a of the projection 14 abuts on the inner wall surface of the resin filling space 9 so that the electric wire branch portion 5 is positioned at the center of the resin filling space 9. The protrusion length L (see FIG. 7) is set.

As shown in FIG. 3, the electric wire branching part 5 having the winding band 12 wound and mounted therein is put in the molding die 8 with the winding band 12 wound, and the electric wire branching part 5 is molded. Go and, as shown in FIG. 4, wire branch 5
A resin coating layer 18 is formed to cover the periphery of the. Note that FIG.
The molding die 8 shown in FIG. 2 is a lower die, and an upper die having a resin filling space of a substantially symmetrical shape and a resin injection port for injecting the molding resin is united with the molding die 8. To be

When the resin coating layer 18 is formed as described above, the outer dimension of the coating layer 18 becomes constant depending on the molding die for molding, so that the finished dimension can be made constant. Further, the electric wire branch portion 5 set in the resin-filled space of the molding die is supported substantially at the center of the resin-filled space by the projection 14 of the winding band 12 pre-wound and mounted on the branch portion 5. The bias of the resin filled in the filling space is prevented.

Therefore, the resin coating layer 18 formed around the branch portion 5 by molding has a substantially uniform thickness over the entire circumference of the branch portion 5. Therefore, there is no variation in mechanical strength, waterproof performance, etc. from the viewpoint of protecting the branch portion 5, and if the material of the resin used for the coating layer 18 is appropriately selected, sufficient protection performance can be obtained. Can be demonstrated.

Further, the winding belt 12 is formed as an integrally molded product of resin as in this embodiment, so that the increase in the number of parts can be suppressed to a minimum, and furthermore, the winding belt attached to the branch portion 5 can be suppressed. 12 is a resin coating layer 1 formed by molding
Since it is buried in 8, there is no extra work after mounting. Therefore, it is possible to reduce the production cost with a small number of working steps.

The wrapping belt 12 is used in the above-described embodiment.
Although the protrusions 14 have a simple columnar shape, the shape of the protrusions 14, the arrangement on the substrate 13, and the like can be appropriately changed in design. Further, the number of the projections 14 is sufficient as long as the position of the electric wire branch portion 5 can be maintained in the molding die, so that a total of six projections 14 are required at each end of the winding band 12.
In addition, as shown in FIG. 4, protrusions 14 are formed on the surface of the coating layer 18.
Since the front end surface 14a of the resin is exposed, the resin material used for the resin coating layer 18 and the resin material used for the winding belt 12 should be selected so that the adhesion between the protrusion 14 and the resin coating layer 18 is enhanced. Further, it is conceivable to provide an adhesive layer to improve watertightness.

[0021]

As described above, according to the coating layer forming method and the coating structure of the electric wire branch portion of the present invention, the resin coating layer is formed by molding, so that the finished size can be made constant. Further, the wire branch portion set in the resin-filled space of the molding die is supported substantially at the center of the resin-filled space by the projection of the wrapping band pre-wound around the branch portion, and is guided into the resin-filled space. It is possible to prevent the branch portion from being biased by the filling pressure of the filled resin.
Therefore, the resin coating layer formed around the branch portion by molding has a substantially uniform wall thickness over the entire circumference of the branch portion, and as the resin coating layer, the mechanical strength and the mechanical strength from the viewpoint of protecting the branch portion and There will be no variation in waterproof performance and the like, and if the material is selected appropriately, sufficient protection performance can be exhibited. Further, since the wrapping band attached to the wire branch portion is buried in the resin coating layer formed by molding, extra work is not required after the attachment. Therefore, it is possible to reduce the production cost with a small number of working steps.

[Brief description of drawings]

FIG. 1 is an external view of an electric wire branch portion in an embodiment of a method for forming a coating layer of an electric wire branch portion according to the present invention.

FIG. 2 is an external view showing a mounted state of the winding band in the method for forming the coating layer of the electric wire branch portion according to the embodiment of the present invention.

FIG. 3 is a perspective view showing a support structure of an electric wire branch portion in a molding die in the method for forming a coating layer of the electric wire branch portion according to the embodiment of the present invention.

FIG. 4 is a perspective view showing an appearance of a resin coating layer of an electric wire branch portion formed by the method for forming a coating layer of the electric wire branch portion according to the embodiment of the present invention.

FIG. 5 is a plan view of a wrapping belt used in an embodiment of the present invention.

FIG. 6 is a view on arrow B in FIG.

FIG. 7 is a view on arrow C in FIG.

FIG. 8 is an external view showing a structure of a wire branch portion.

FIG. 9 is an external view showing a state in which a tape is wound around an electric wire branch portion.

FIG. 10 is a perspective view showing a conventional resin molding method for forming a resin coating layer on a wire branch portion.

[Explanation of symbols]

1 trunk cable 4 branch electric wires 5 Electric wire branch 8 Mold Mold 9 resin filling space 10 tape winding 12 winding incidental 13 board 14 Protrusion 18 Resin coating layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-127387 (JP, A) JP-A-3-49206 (JP, A) JP-A-6-334109 (JP, A) Actual development Sho-54- 173992 (JP, U) Actual development Sho 63-128684 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01R 4/70 H01B 7/00 305 H01R 4/18 H01R 43/00 B29C 45/02 B29C 45/36

Claims (4)

(57) [Claims] 1. A method for forming a coating layer at an electric wire branching portion in which a branching electric wire is connected to a main electric wire, wherein a winding band made of an insulating material having a plurality of projections of a predetermined length is provided so that the projections face outward. Around the electric wire branching portion, tape both ends of the winding band to the main electric wire, and put the electric wire branching portion with the winding band wound in a mold die, thereby A method for forming a coating layer of an electric wire branch portion, which comprises performing positioning for a length apart from an inner wall of a mold and performing mold forming on the electric wire branch portion. 2. The method for forming a coating layer of a wire branch portion according to claim 1, wherein an adhesive for sealing a protrusion is applied after the winding band is fixed to the wire branch portion. 3. A covering structure of an electric wire branching part in which a branching electric wire is connected to a main electric wire, wherein a protrusion is provided on one surface of a substrate provided with a predetermined flexibility so as to be wound around the electric wire branching part. A wrapping band made of an insulating material having a shape provided with a protrusion, a fixing means for fixing the wrapping band to the main electric wire, and a wrapping band including the wrapping band whose thickness is determined by the protrusion in a molding die. A coating structure for a wire branch portion, comprising: a resin coating layer that covers the entire wire branch portion. 4. The covering structure for an electric wire branch portion according to claim 3, further comprising a sealing adhesive provided between the winding band and the resin coating layer.