Wiring structure and method for wiring electrical wire on base member

A wiring method for an electrical wire 3 is provided. In the resultant wiring structure, an insulating base member 11 is provided with a plurality of projections 12 formed along a designated wiring route. Each projection 12 is provided with a dented top for receiving the wire 3. By using an ultrasonic welding machine, the wire 3 is welded on the projections 12 in order, while wiring the wire 3 on the insulating base member 11. The insulating base member 11 has a plurality of shelf portions providing a three-dimensional structure.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a wiring structure where an electrical
 wire is wired and fixed on an insulating base member and a wiring method
 of producing such a wiring structure. More particularly, it relates to a
 wiring structure which will be appropriate for wiring a wire harness about
 a door trim for an automobile, the rear lamp, or the like.
 2. Description of the Related Art
 An ordinary wiring structure is disclosed in Japanese Unexamined Utility
 Model Publication (kokai) No. 5-46608. In this wiring structure, an
 insulating base member is disposed inside a door trim of an automobile. On
 a top surface of the base member, a plurality of slits are formed so as to
 extend along wiring routes designated for electrical wires. In wiring, the
 electrical wires are embedded into the slits of the base member,
 respectively. In this way, the electrical wires are arranged on the base
 member.
 Similarly to the above wiring structure, Japanese Unexamined Utility Model
 Publication Nos. 7-20030 and 55-155022 disclose another wiring structure
 where the wires are fixed on the base member through the intermediary of
 fixtures different from the base member, for example clamps.
 In the former conventional wiring structure, however, it is necessary to
 form many slits on the base member along each wiring route. Thus, when
 many wiring routes are required for the base member, then a problem arises
 in terms of the wiring workability. Especially, when it is required to lay
 the electrical wires on the so-called "three-dimensional" complicated base
 member, the wiring operation is too complicated to accomplish such a
 wiring operation on the manufacturing line for products.
 On the other hand, in the latter structure where the wires are fixed on the
 base member by the fixtures, there is still remained a difficulty to fix
 the wires on the base member securely, thereby causing the unstable
 fixation of the wires. Additionally, due to a great number of fixtures to
 be handled, the wiring workability is deteriorated accordingly.
 SUMMARY OF THE INVENTION
 Under such a circumstance, it is therefore an object of the present
 invention to provide a wiring structure for an electrical wire and a
 wiring method of producing the wiring structure, by which it is possible
 to arrange the electrical wire on an insulating base member easily and
 certainly and also possible to facilitate the wiring of electrical wire
 against such a three-dimensional base member as mentioned above.
 The object of the present invention described above can be accomplished by
 a wiring structure comprising:
 an insulating base member made of an insulating material;
 a plurality of projections formed integrally with the insulating base
 member so as to project at respective positions designated on the
 insulating base member; and
 an electrical wire laid on the projections so that the electrical wire can
 be welded to the projections.
 With the wiring structure mentioned above, when successively welding the
 electrical wire to the projections of the insulating base member, the
 electrical wire is secured on the insulating base member through the
 projections. In other words, owing to the provision of the projections on
 the base member, the electrical wire can be easily fixed on the insulating
 base member without forming any conventional slit on the insulating base
 member. In addition, since the wire is certainly fixed on the insulating
 base member through the projections formed integrally with the member,
 there is no need to prepare the conventional clamp etc. in order to fix
 the wire on the insulating base member.
 In the present invention, preferably, the insulating base member is formed
 to have a three-dimensional structure of a designated profile and each of
 the projections is provided, on a top thereof, with a dint for receiving
 the electrical wire therein.
 In this case, since the wire is retained in the respective dented tops of
 the projections, it is possible to easily and surely fix the electrical
 wire on the insulating base member even granting that it has a complicated
 "three-dimensional" structure.
 In the present invention, more preferably, the projections are positioned
 along a wiring route to be designated on the insulating base member. In
 this case, it is possible to lay the electrical wire along the
 predetermined wiring route.
 In the present invention, more preferably, the insulating member has a bore
 formed on the wiring route, for dividing the electrical wire into a
 plurality of wire portions. In this case, owing to the provision of the
 bore, it is possible to define a plurality of wiring routes consisting of
 the wire portions, on the insulating base member.
 In the present invention, more preferably, the insulating member is
 provided, in the bore, with a plurality of notches for engagement with a
 lamp holder for an automobile. In this case, it is possible to support the
 lamp holder by the bore of the insulating base member.
 According to the present invention, there is also provided a method of
 producing the above wiring structure, the method comprising the steps of:
 integral-molding an insulating base member provided with a plurality of
 projections at designated positions on the insulating base member;
 preparing an electrical wire;
 successively welding the electrical wire onto the projections of the
 insulating base member while laying the electrical wire on the
 projections. In the above-mentioned method, since the wiring is carried
 out while holding the wire by the projections, the workability in wiring
 can be improved, thereby allowing the automatic wiring of the electrical
 wire. In the integral-molding step, preferably, the insulating base member
 is formed to have a three-dimensional structure of a designated profile by
 a vacuum molding method. In this case, it is possible to wire the
 electrical wire on the insulating base member having the complicated
 "three-dimensional" structure. That is, the accurately-wired product can
 be produced at a low cost.
 In the above-mentioned method, preferably, the projections are positioned
 along a wiring route to be designated on the insulating base member. Also
 in this case, it is possible to lay the electrical wire along the
 predetermined wiring route.
 In the above-mentioned method, more preferably, it further comprises the
 step of punching the insulating base member having the electrical wire
 welded on the projections, thereby to form a bore positioned on the wiring
 route, for dividing the electrical wire into a plurality of wire portions.
 In this case, owing to the provision of the bore, it is possible to define
 a plurality of wiring routes consisting of the wire portions, on the
 insulating base member.
 In the above-mentioned method, it is preferable that the welding step is
 carried by using an ultrasonic welding machine. In this case, the welding
 operation for the wire can be simplified due to the facility of ultrasonic
 welding.

DESCRIPTION OF THE PREFERRED EMBODIMENT
 Embodiments of the present invention will be described hereinafter, with
 reference to the accompanying drawings.
 FIGS. 1A to 6 show respective steps of wiring an electrical wire in due
 order, in accordance with the embodiment of the present invention.
 According to the embodiment, a resinous material 10 in the form of a
 rectangular plate is firstly prepared and subsequently molded into a base
 member 11 on which the electrical wire 3 has to be wired, by the vacuum
 molding technique using a molding die 5 shown in FIG. 1A. Note, although a
 covered wire is representative of the electrical wire 3 in the shown
 embodiment, it may be replaced with a bare wire, an enamel wire, or the
 like. The molding die 5 is provided, in a center thereof, with a
 projection which protrudes from the upper face. The projection is
 constituted by three molding faces 5a, 5b and 5c forming two steps on the
 upper face. Along some wiring routes designated on the molding faces 5a,
 5b and 5c, a plurality of dented ribs 5d are formed integrally with the
 molding die 5, as shown in FIGS. 1A and 1B.
 In order to weld the wire 3 on the insulating base member 11, a wiring
 machine 6 as shown in FIGS. 4A, 4B and 5A is employed. The wiring machine
 6 operates to continuously withdraw the electrical wire 3 from a not-shown
 wire roll and serves to dispose the wire 3 on the base member 11.
 Additionally, the shown wiring machine 6 also serves as an ultrasonic
 welding machine. In this point of view, the machine 6 is equipped with a
 wire holding cylinder 7 having an ultrasonic horn 8 on the tip, for the
 ultrasonic oscillation. Moreover, the wire holding cylinder 7 is provided,
 on upper and lower portions thereof, with wire through-holes 7a, 7b,
 respectively. Owing to the above-mentioned structure of the machine 6, it
 allows the wire 3 to be disposed on the base member 11 while being tensed.
 With reference to FIGS. 1A to 6, we now describe the wiring steps for the
 wire 3 in accordance with the embodiment, in detail.
 As shown in FIGS. 1A and 2, by deforming the resinous insulating material
 10 in the form of a rectangular plate by the vacuum-molding technique
 using the molding die 5, a provisional "vacuum-molding" product 10' is
 provided to have the projecting base member 11 integrally formed at a
 center of the product 10'. Then, the provisional product 10' is subjected
 to either punching or cutting process to eliminate the superfluous
 periphery of the central projecting portion, so that the base member 11
 can be provided to have a generally-triangle profile in plan view, as
 shown in FIG. 3A. The resultant base member 11 has a first shelf portion
 11a in the form of a high bunk, a second shelf portion 11b in the form of
 a middle bunk and a third shelf portion 11c in the form of a low bunk,
 providing the so-called "three-dimensional structure" for the member 11.
 In other words, the base member 11 has three steps. Additionally, during
 the vacuum molding for the base member 11, a plurality of projections 12
 each having a dented tip 12a are formed integrally with the member 11, for
 retaining the wire 3 along the wiring routes defined on the shelf portions
 11a, 11b and 11c. As shown in FIG. 3B, owing to the provision of the
 dented tip 12a of each projection 12, the arranging of the wire 3 on the
 projections 12 allows the wire 3 to be temporarily fixed on the respective
 projections 12 of the base member 11 with ease, so that no positional
 deviation of the wire 3 from the wiring routes is produced at the time of
 wiring the same on the member 11.
 Next, as shown in FIG. 4A, the wiring machine 6 also serving as an
 ultrasonic welding machine is driven and finally stopped on the upside of
 the specified (initial) projection 12 as a starting point for wiring on
 the first shelf portion 11a of the base member 11, by a not-shown
 six-spindle robot. Subsequently, on the completion of disposing the
 electrical wire 3 on the tip 12a of the initial projection 12 through the
 lower through-hole 7b in the wire holding cylinder 7 projecting from the
 wiring machine 6, then the tip 12a of the projection 12 is oscillated with
 ultrasonic waves by the horn 8 at the tip of the wire holding cylinder 7
 of the wiring machine 6. By the ultrasonic oscillation, as shown in FIG.
 5B, the tip 12a of the projection 12 is molten to weld the wire 3 to the
 projection 12, so that the wire 3 is secured on the base member 11.
 Simultaneously, since an insulating cover 3b covering a core line 3a of
 the wire 3 is also fused together with the tip 12a of the projection 12,
 the wire 3 can be surely fixed on the base member 11.
 Next, as shown in FIG. 5A, the wire 3 is welded and secured to the second
 projection 12 on the shelf portion 11a of the base member 11 by means of
 the horn 8 while applying tension on the wire 3 by the wire through-holes
 7a, 7b of the wire holding cylinder 7 of the wiring machine 6. On the
 completion of welding the wires 3 (of two wiring routes) to the
 projections 12 on the first shelf portion 11a of the base member 11 in the
 above way, the same operation is transferred to the projections 12 on the
 second shelf portion 11b and the sequent projections 12 on the third shelf
 portion 11c successively. The finished product 11A resulting from such
 wiring and welding is shown in FIG. 6.
 Thus, by the adoption of such a wiring process for the wire 3, it is
 possible to smoothly arrange and fix the wire(s) 3 on the base member 11
 in a short time even granting that it has such a complicated
 "three-dimensional" structure. Additionally, as there is no need to
 provide the afore-mentioned slits or the separate members, for example
 clamps in order to fix the wire(s) 3 on the base member 11, it is possible
 to produce the finished product 11A of extreme accuracy at a low cost.
 Further, since the laying of the wire 3 is carried out under condition that
 it is held on the projections 12, it is possible to fix the wire 3 on the
 accurate position of the base member 11 through the projections 12 easily
 and certainly, whereby the workability in wiring can be improved
 furthermore.
 Moreover, when the wiring machine 6 is controlled so as to freely move in
 the three-dimensional directions by means of the robot, then the automatic
 wiring of the wire 3 can be realized though the base member 11 is of the
 complicated "three-dimensional structure" while accompanying a likelihood
 of the rapid and "labor-saving" wiring.
 FIG. 7 shows a modified product 11B which may be obtained by applying a
 further machining on the finished product 11A provided by the
 above-mentioned wiring method. At predetermined positions on the base
 member 11, the modified product 11B has a plurality of bores 13 formed by
 punching the member 11. These bores 13 are utilized for fixing the product
 11B on a lamp holder 23 of a rear lamp 20 which will be mentioned later.
 Each of the bores 13 has a function to divide the wire 3 into plural
 wires, also. That is, since the single wire 3 is divided into some wire
 parts by providing the bores 13, it is possible to define more circuits on
 the base member 11.
 In FIG. 7, it is noted that reference numerals 14 indicated by dots
 designate respective fixing points where the electrical wires 3 are fixed
 on the base member 11 through the molten projections 12. Although the base
 member 11 of FIG. 7 has the bores 13 punched at the predetermined
 positions, the member 11 may be provided with further grooves (not shown)
 so that the single wire 3 is divided into a plurality of wire parts by the
 bores 13 and the above grooves, in the modification.
 FIG. 8 shows an embodiment where the above modified product 11B is applied
 on the rear lamp 20 for the automobile. The rear lamp 20 comprises a
 transparent casing 21 in the form of a generally triangular corn, which is
 made of synthetic resin and provided with a red portion and two whitish
 parallel bands at the center of the red portion, a generally trapezoidal
 reflector 22 attached to the casing 21, the applied product 11B to be
 mounted on the reflector 22, and some detachable lamps 24 (only one shown
 in FIG. 9B) which are fitted in the bores 13 in the base member 11 of the
 product 11B through the intermediary of lamp holders 23.
 Formed about the respective bores 13 of the base member 11 are patterns 15
 to which the divided wires 3 are respectively connected. Again, each of
 the bores 13 is provided with four notches 13a for engagement and
 disengagement with the lamp holder 23. On the other hand, the lamp holder
 23 has projecting claws 23a formed in opposition to the notches 13a,
 respectively. The reflector 22 has a plurality of openings 22a formed in
 respective positions opposing to the bores 13 in the base member 11.
 With the above-mentioned structure, by inserting the claws 23a of the lamp
 holder 23 into the notches 13a of one bore 13 in the base member 11 and
 sequent rotating the lamp holder 23 for engaging the claws 23a with the
 member's back 11d about the bore 13, it is possible to provide a structure
 allowing the lamp 24 to be easily attached on the side of the reflector
 22. Then, as shown in FIGS. 9A and 9B, terminals 25 protruding from a rim
 23b of the lamp holder 23 are electrically connected to the patterns 15
 about the bore 13.
 In this way, owing to the use of the applied product 11B as a baseplate for
 the rear lamp 20, the wiring work of the rear lamp 20 can be simplified
 extremely. Additionally, with the work to only rotate the lamp holder 23
 about the bore 13, it is possible to fit the lamp 24 in the lamp holder 23
 with ease. Furthermore, since the base member 11 is attachable along the
 reflector 22 having a complicated structure, it is possible to provide a
 thin, small-sized and lightweight rear lamp 20.
 In the above-mentioned embodiment, although the wiring structure of the
 invention is applied in connection with the rear lamp of the automobile,
 of course, the present invention is applicable to other instruments, such
 as a door trim of the vehicle.
 Finally, it will be understood by those skilled in the art that the
 foregoing description is related to one preferred embodiment of the
 disclosed wiring structure and method, and that various changes and
 modifications may be made to the present invention without departing from
 the spirit and scope thereof.