Fuse box device

Abstract: The fuse box device comprises a fuse box (21) and a fuse unit (1) contained therein. The fuse unit (1) includes an input terminal (3) directly connectable to a battery, several output terminals (4) connectable to a wire harness, and several fuse element portions (5). One end of the fuse element portions (5) is integrally formed with the input terminal (3), whilst the other end of the fuse element portions (5) is integrally formed with the output terminals (4). The fuse unit (1) is contained in the fuse box (21), such that only the input terminal (3) projects out of the fuse box (21). In such a construction, the fuse box device requires a reduced number of spare parts, so that production costs can be lowered. Moreover, the fuse box device is better adapted to a miniaturization and less susceptible to assembling errors.

Description: The present invention generally relates to a fuse box device comprising a fuse unit and a fuse box housing the latter. Such a fuse box device can usually be fitted directly to a battery mounted in automobiles. An example of a known fuse box device is shown in Fig.1. In this figure, the fuse box device 61 includes a fuse box 62, in which a plurality of flat fuses 63 are provided. The flat fuses 63 are formed of an electrically conductive metal plate, and each of them comprises a fuse element portion 64 interposed between two ear portions with a respective ear hole for bolting 65. The fuse box 62 is manufactured by molding a resin. It has a concavity 66 capable of containing a plurality of flat fuses 63. The base of the concavity 66 is provided with one or several flat input nuts 67 and flat output nuts 68. Both flat nuts 67 and 68 are insert-molded. The flat input nut 67 is fixed to a terminal which is directly attached to a battery (not shown in the figures). To this end, the flat input nut 67 has a nut hole for bolting. When a flat fuse 63 is mounted in the fuse box 62 and the nut hole is fitted with a bolt 69, a first end portion of the flat fuse 63 is connected and fixed to the flat input nut 67. Likewise, the flat output nut 68 has a nut hole for bolting. A second end portion of the flat fuse 63 is connected and fixed to the flat output nut 68 through a bolt 69 in the same manner. In a wire harness 70 containing several electrical cables 71, each electrical cable 71 is fitted with an LA terminal 72 (or a ring terminal). The LA terminal 72 can thus be connected and fixed to the flat output nut 68 through the bolt 69, together with the flat fuse 63. Further, the fuse box 62 is protected by a fuse cover 73. In the prior art, the flat fuses 63 and the terminal directly connectable to a battery were prepared separately, and fixedly connected to each other through flat input nuts 67 and bolts 69. Likewise, the flat fuses 63 and the LA terminals 72 were prepared separately, and connected to each other through flat output nuts 68 and bolts 69. Such a fixing mechanism necessarily increases the number of component parts used and, consequently, production costs. In addition, such a fixing process, carried out during manufacture, tends to cause spurious fixtures, e.g. skewed fixing, or to simply omit fixing in some cases. To avoid such situations, a high level of process control has to be implemented. In general, the size of flat input nuts 67 and flat output nuts 68 determines the total size of a fuse box device 61. However, there is a certain limit to miniaturizing such flat nuts 67 and 68. Moreover, when a flat fuse 63 is to receive a large electric current, sufficiently large flat nuts 67 and 68 must be used in order to reduce electrical resistance. This in turn makes miniaturization more difficult. The present invention has been contemplated in view of solving such problems. The fuse box device according to the present invention needs only a limited number of component parts and is better adapted to miniaturization than the conventional devices. Its construction is conceived such as to reduce fixing errors and can be implemented at lower costs. To this end, there is provided a fuse box device comprising a fuse unit and a fuse box, the fuse unit including at least one fuse element portion having a first end portion and a second end portion. The first end portion is integrally formed with an input terminal directly connectable to a battery, whilst the second end portion is integrally formed with at least one output terminal connectable to a wire harness. The fuse unit is then contained in the fuse box such that only part or the entirety of the input terminal is placed outside the fuse box. Preferably, the fuse unit comprises an insulator-molded portion at least covering the fuse element portions. Preferably yet, the at least one output terminal comprises a plurality of output terminals and the fuse box contains at least one insulator partition wall such as to define a plurality of enclosures, so that each of the enclosures contains an output terminal connectable to a press-fit terminal of one of the electrical cables which constitute a wire harness. Suitably, the fuse box comprises at least one holder means for defining a fixing position for the fuse unit and fixing the latter in the fuse box by holding part of the fuse unit by the holder means. Typically, the fuse box comprises two opposing inner faces, the insulator partition wall(s) has/have a top portion, and the fuse box device further comprises a cover joint having an inner face. The at least one holder means is then selected from the group consisting of: at least one slit formed in the insulator partition wall(s) such as to extend from the top portion thereof to a half-way point downwards; two pairs of ribs formed in the opposing inner faces of the fuse box at positions corresponding to those of the slit(s); and two pairs of ribs formed in the inner face of the cover joint at positions corresponding to those of the slit(s). In the above construction, the part of the fuse unit may comprise the insulator-molded portion. According to a first aspect of the invention, an end portion of a fuse element portion is integrally formed with a terminal that is directly connectable to a battery. Accordingly, hitherto used fixing means such as nuts and bolts can be obviated. Further, the other end portion of the fuse element portion is integrally formed with a male tab that is connectable to a wire harness. Consequently, the fuse element portion and the wire harness can be easily connected without using any fixing means. The number of parts used is thus reduced, and manufacturing costs are also lowered to a minimum. Besides, as the fixing means are obviated, spurious fitting during manufacture can be avoided, and the fuse box device as a whole can be miniaturized. According to a second aspect of the invention, part of the fuse unit is sandwiched by the holder means, so that the fuse unit is placed at a given position in the fuse box, and fixed therein. Accordingly, it is no longer needed to use the conventional means for fixing the fuse unit in the fuse box. This feature also contributes to the reduction of parts number, costs and size. According to a third aspect of the invention, upon mounting the fuse element portion into the fuse box, each male tab is inserted into a press-fitting terminal, through which the male tab is electrically connected to a wire harness. As a result, it is no longer necessary to use LA terminals and related fixing means for binding the male tabs and the wire harness. Moreover, the press-fit terminals are separated from each other by an insulator wall, so that a short circuit between the press-fit terminals can be avoided. Furthermore, both the male tabs and the press-fit terminals are securely contained in a fuse box, so that they are better protected from external influences such as water contact. According to a fourth aspect of the invention, the conductive fuse element portion is protected by molded resin. This molded resin makes the fuse element portion less susceptible to strain, and the fuse element portion procures a higher mechanical strength. At the same time, the molded resin improves the insulating and waterproof quality of the fuse box. The above and the other objects, features and advantages of the present invention will be made apparent from the following description of the preferred embodiments, given as non-limiting examples, with reference to the accompanying drawings, in which: Fig.1 is a perspective view of a disassembled fuse box device known in the prior art; Figs.2 (a), (b), (c) and (d) illustrate a fuse unit of the invention, respectively by a top plan view, a front elevational view, a side elevational view and a rear elevational view; Figs.3 (a), (b) and (c) are respective front elevational views of the inventive fuse unit, at different stages of manufacture explaining how the fuse unit is made; Figs.4 (a), (b), (c) and (d) illustrate a fuse box according to the present invention, respectively by atop plan view, a front elevational view, a side elevational view and a rear elevational view; Figs.5 (a), (b) and (c) are cross-sectional views taken along line A-A of Fig.4 (a), a cross-section along line B-B of Fig.4 (a), and a cross-section along line C-C of Fig.4 (b); Figs.6 (a), (b), (c), (d) and (e) illustrate a fuse cover of the inventive fuse box device, respectively by a top plan view, a front elevational view, a cross-sectional view along line D-D of Fig.6 (b), a side elevational view and a rear elevational view; Fig.7 is a bottom plan view of a cover joint forming part of the fuse cover of Fig.6; and Figs.8 (a), (b) and (c) illustrate the fuse unit when it is contained in the fuse box, respectively by a top plan view, a front elevational view and a side elevational view. The fuse unit 1 constituting the fuse box device shown in Fig.2 is formed of an electrically conductive plate, e.g. a metal plate. Examples of metals forming the electrically conductive plate include silver, copper, zinc, tin, lead and an alloy made with one or more of those metals. An input terminal 3 for a battery, output terminals 4 (male tabs) and fuse element portions 5 are integrally formed from the electrically conductive plate. The input terminal 3 intended to be connected to a power-supply terminal of a car battery, and comprises a first strip 3a (placed vertically in normal use) and a second strip 3b (placed horizontally in normal use). The former is larger than the latter. One end of the second strip 3b (horizontal strip) is linked to the top end of the first strip 3a (vertical strip). The second strip 3b is formed into an inverted U-shape, when viewed along its cross-section. A locus near the second end of the second strip 3b, and a half-way point widthwise thereof, is provided with a substantially round hole 6 for bolting. The input terminal 3 can thus be fitted with a power-supply terminal by fixing the nut and bolt through the round hole. The fuse unit 1 comprises e.g. four output terminals 4 (male tabs) and four fuse element portions 5. Each of the fuse element portions 5 is curved into an S-shaped plane, and has a width considerably narrower than that of a male tab 4. One end of the fuse element portion 5 is linked to the lower part of the first end of the second strip 3b. The other end of the fuse element portion 5 is linked to the top end of the male tab 4. Accordingly, the fuse element portion 5 connects the input terminal 3, connectable to a battery, to each male tab 4. Part of the electrically conductive plate (i.e. the first strip 3a in its entirety and the upper zone of the male tabs 4) is coated by molding an insulator material, thereby forming an insulator-molded portion 7. Accordingly, the area including the fuse element portions 5 is molded with the insulator material. The latter has a thin, plate-like shape. The insulator material used in the invention includes e.g. a resin such as epoxy resin. A predetermined locus in the insulator material is provided with four openings 8 having e.g. a square shape. Through these openings 8 are exposed the fuse element portions 5 to outside the insulator material. The fuse unit 1 shown in Fig.2 takes a rake-like form, that is, one input terminal 3, directly connectable to a battery, branches into four male tabs 4. The fuse unit 1 is manufactured according to the steps shown in Fig. 3 (a), (b) and (c). First, a non-transformed electrically conductive plate 2 is prepared. The conductive metal plate 2 is then stamped out to yield, integrally, an input terminal 3 for battery connection, four male tabs 4 and three tie bars 11. The tie bars 11 may have the same thickness as the conductive metal plate 2, but they may also be made thinner, for example by half-etching. Preferably, each tie bar 11 is formed at a position unshielded by the insulator material, e.g. at an end portion of the male tab 4. Further, a bolt hole 6 may be formed at the same time as the conductive metal plate 2 is stamped out. The conductive metal plate 2 is then transformed into a piece having a substantially L-shaped cross-section by bending using a purpose made tool. An area, which includes loci intended to lodge subsequently the fuse element portions 5 (element-forming locus 12), is initially insert-molded with an insulator material. At the same time, insulator openings 8 are formed in the insulator material, so that only the element-forming loci 12 are exposed to the outside through the insulator openings 8. To form the insulator openings 8, the insert-molding die may carry e.g. convexities which are prepared in advance and adapted to form such openings. The exposed element-forming loci 12 are then stamped out so as to form four fuse element portions 5 and, at the same time, remove three tie bars 11. The male tabs 4 are thus separated from each other to form a desired fuse unit 1 shown in Fig.2 (a), (b) and (c). The fuse unit 1 thus produced is inserted into a fuse box 21 shown in Figs.4 (a), (b), (c) and (d), and subjected to use. The fuse box 21 is a tubular resin product. The resin materials used include an insulator resin such as ABS resin. The fuse box 21 has a rectangular top orifice 22 and a likewise-configured bottom orifice 24. The outside rim portion of the top orifice 22 is integrally provided with a plurality of first fixing mounts 27 and a flat fixing portion 28. When the fuse unit 1 is installed into the fuse box 21, the second strip 3b of the fuse unit 1 is placed on the flat fixing portion 28 and maintained thereon. In this state, the second strip 3b extends outwardly from the fuse box 21. Accordingly, even when the fuse unit 1 is inserted into the fuse box 21, the input terminal 3 is directly connectable to a power-supply terminal of a battery. The inside space of the fuse box 21 is provided with insulator partition walls 23. In the present embodiment, the fuse-box inside is divided into four enclosures by three insulator partition walls 23. The partition walls 23 are integrally formed with the fuse box 21 in a resin. These walls 23 extend from the top to the bottom of the fuse box 21 in parallel relation to each other, with a constant interval therebetween. The three partition walls 23 thus form four enclosures S1, each of which can lodge a rectangular columnar press-fit terminal (not shown in the figures). Preferably, a portion of the inner face of fuse box 21 contained in each enclosure S1 is provided with a lance structure in order to hang the press-fit terminal. The bottom orifice 24 has four substantially square openings. The other end of the press-fit terminal is further press-fitted with an electrical cable that forms a wire harness. A top portion of each partition wall 23 is provided with a slit 25 extending from the top to a half-way point downwards. The width of the slit 25 substantially corresponds to the thickness of the insulator-molded portion 7 of the fuse unit 1, so that the fuse unit 1 is held in the fuse box 21 by inserting the insulator-molded portion 7 into the slit 25 (see Fig.8). The fuse unit 1 is thus placed and fixed at a predetermined position in the fuse box 21. In other words, the slit-forming locus 25a in a partition wall 23 holds the fuse unit 1 by flanking a part of the front and rear faces of the insulator-molded portion 7. The slit-forming locus 25a thus serves as a first holder means for positioning and fixing the fuse unit 1. Two opposing positions on the small inner surfaces of the fuse box 21, corresponding to the positions of the slits 25, are provided with a respective pair of box ribs 26. The two pairs of box ribs 26 extend in parallel relation to each other, from the top of the fuse box 21 to half-way downwards. These box ribs 26 are integrally formed with the fuse box 21 in a resin material. The space between the two box ribs 26 of each pair is arranged to correspond to the thickness of the insulator-molded portion 7 of the fuse unit 1. As a result, the fuse unit 1 can be fixed at a predetermined position in the fuse box 21. In other words, each pair of box ribs 26 places and fixes the fuse unit 1 at a predetermined position by holding two ends of the insulator-molded portion 7. The box ribs 26 thus serves as a second holder means, as well as a means for guiding the fuse unit 1 when it is inserted into the fuse box 21. Figs.6 and 7 show a fuse cover 41 for protecting the fuse unit 1. The fuse cover 41 is made of an insulator material e.g. a resin. The fuse cover 41 comprises a cover plate 42, a cover joint 43 and a hinge portion 44 connecting them. The cover plate 42 covers the power-supply terminal connectable to a battery mounted in an automobile, and protects the terminal from water and dust. The top face of the cover plate 42 is provided with a mark to show that it encloses a power-supply terminal. The cover joint 43 is installed so as to close the top orifice 22 of the fuse box 21. The cover joint 43 carries integrally formed second fixing mounts 45 at positions corresponding to those of the respective first fixing mounts 27. Accordingly, when the fuse cover 41 is placed on the fuse box 21, the second fixing mounts 45 are hooked by the first fixing mounts 27. The cover joint 43 is thus securely fixed onto the top orifice 22 (see Fig. 8). There are provided two pairs of cover ribs 46 in the underside of the cover joint 43. The space between the cover ribs 46 is designed to be substantially the same as the thickness of the insulator-molded portion 7 of the fuse unit 1. Accordingly, when the fuse unit 1 is installed into the fuse box 21 and the fuse cover 41 is placed thereon, the two top ends portions of the insulator-molded portion 7 are held by the two pairs of cover ribs 46 (see Fig.8). In this manner, the fuse unit 1 can be placed at a predetermined position in the fuse box 21 and securely fixed therein. The cover ribs 46 thus hold parts of fuse unit 1, i.e. the upper rim portion of the insulator-molded portion 7, and fix the fuse unit 1 at a predetermined position. The cover ribs 46 thus serve as a third holder means of the fuse unit 1. The cover joint 43 provided with cover ribs 46 prevents the fuse unit 1 from being occasionally drawn out of the fuse box 21. It also protects the fuse element portions 5 from water and dust. As can be understood from the foregoing description, the present invention provides the following advantages. In the fuse unit 1 of the present invention, an input terminal 3, directly connectable to a battery, is integrally formed with four fuse element portions 5 through one end thereof. Accordingly, it is no longer needed to provide fixing means such as nuts and bolts, used for fixing the fuse elements portions 5 to the input terminal 3. Further, the other ends of the four fuse element portions 5 are also formed integrally with output terminals 4 (male tabs) for wire harness connections. Accordingly, the fuse element portions 5 and the wire harness can be connected easily without using such fixing means as nuts and bolts. From the foregoing, the inventive fuse box 21 needs a smaller number of spare parts, and can be manufactured at lower costs. As the fixing means have been obviated, there will be no spurious fixing such as skew fixing or fixing omission. Production control for such fuse boxes thus becomes much easier, and the production efficiency is improved. Large scale installations for bolting are also rendered unnecessary, thereby preventing an increase of equipment costs. Furthermore, the use of nuts, determinant for the size of the fuse box 21, is suppressed. The new structure without nuts thus greatly helps towards the miniaturization of the fuse box 21. The fuse box 21 contains a first and a second holder means which position and fix the fuse unit 1 by pinching parts of fuse unit 1. By virtue of these holder means, the fuse unit 1 is fixed at a predetermined position in the fuse box 21. Accordingly, use of the binding means, otherwise required for fixing them, are dispensed with. A reduction in the number of spare parts used, lowering of costs, and miniaturization of the fuse box 21 can thus be achieved simultaneously. The inside of the inventive fuse box 21 is provided with insulator partition walls 23, which define four terminal enclosures S1 for containing four male tabs 4. Accordingly, when the fuse unit 1 is inserted into the fuse box 21, each male tab 4 is fitted into a corresponding press-fit terminal. The male tab 4 is thus electrically connected to the wire harness through the press-fit terminal. Accordingly, it is no longer required to use LA terminals (or ring terminals) and the fixing means thereof, which were otherwise used for connecting the male tab 4 to the wire harness. The advantage of using the press-fit terminals is that connections to the wire harness are made merely by press-fitting, without recourse to holder means. Each press-fit terminal is separated from the other by an insulator partition wall 23, so that the short circuit between the press-fit terminals can be avoided from the outset. The partition walls 23 thus contribute greatly to the reliability of the fuse box 21. Both the male tabs 4 and the press-fit terminals are stored in the fuse box 21, and are thus not exposed to the outside influences such as water splash. The reliability of the fuse box 21 is thus further improved. The fuse box 21 of the invention comprises a first, a second and a third holder means. These holder means hold several positions of the fuse unit 1, so that the latter can be securely placed at a predetermined position and fixed thereto in the fuse box 21. By virtue of this construction, the fuse box 21 resists better against shocks and vibrations, and its reliability is improved. In the inventive fuse unit 1, the area including the fuse element portions 5 is resin molded. In other words, the conductive fuse element portions 5 are protected with the insulator material. The fuse element portions 5 are thus less susceptible to strain, and the fuse unit 1 procures a higher mechanical strength. Further, the insulator material ensures better insulating and waterproof properties. The number of male tabs 4 used as output terminals may be one, two or three. It may also be more than four. The form of male tabs 4 may also be modified as desired. Likewise, the input terminal 3 may have a configuration other than that described above, or may not include the hole 6 for bolting. The fuse unit 1 itself may have a shape other than a rake-like shape. The insulator material used is not limited to the above-mentioned resin or mold resin, but may be e.g. rubber. Likewise, the insulator may be formed by a method other than the insert-molding. The fuse unit 1 may also not include an insulator material such as the mold resin. The fuse box 21 may further be made without one or two of the first, second and third holder means. The configuration of the holder means may be changed. Further technical concepts of the present invention will be made apparent from the following description. The terminal directly connectable to a battery may relate to a power-supply terminal for a battery mounted in an automobile. The holder means may comprise a slit formed in a partition wall such as to extend from the top of the wall to a half-way point downwards. The insulator-molded portion of the fuse unit may then be inserted into the slit, so that the former is placed at a predetermined position and securely held by the slit. The holder means may comprise two pairs of box ribs formed on the inner face of the opposing small planes of the fuse box, at positions corresponding to those of the slits. The box ribs sandwich two side rims of the insulator-molded portion of the fuse unit, so that the fuse unit is placed at a predetermined position and fixed thereto. The fuse box may comprise a fuse cover made of an insulator material. The fuse cover may include a cover plate which covers the part of fuse unit extending outwards from the fuse box, a cover joint which covers the top orifice of the fuse box, and a hinge portion linking the cover plate and the cover joint. The inside face of the cover joint may comprise a holder means which can sandwich part of the fuse unit, and fix its position. The fuse box device comprises a fuse unit and fuse box. Further, the fuse box comprises holder means which flank the fuse unit, fix its position and hold it securely. The fuse unit in the above fuse box device may comprise a terminal directly connectable to a battery, several fuse element portions and several male tabs connectable to a wire harness. The fuse box in the above fuse box device includes insulator partition walls which form enclosures for a respective press-fit terminal. Each enclosure then receive a male tab. The fuse box device according to a first embodiment of the invention utilizes a reduced number of spare parts, compared to the known fuse box devices. Production costs therefore less, is better adapted to a miniaturization, and is less susceptible to assembling errors. The holder means according to a second embodiment of the invention further contributes to reducing the number of spare parts, lowering production costs and miniaturizing the fuse box device. The partition walls according to a third embodiment of the invention ensures for the fuse box device an electrically reliable functioning.

Claims: A fuse box device comprising a fuse unit (1) and a tubular fuse box (21), said fuse unit (1) including at least one fuse element portion (5) having a first end portion and a second end portion, characterised in that said first end portion is integrally formed with an input terminal (3) directly connectable to a battery, said second end portion is integrally formed with at least one output male tab (4) connectable to a wire harness, and said fuse unit (1) being held in said fuse box (21) in such a way that only a part or the entirety of said input terminal (3) is placed outside said fuse box (21). The fuse box device according to claim 1, wherein said fuse unit (1) comprises an insulator-molded portion (7) at least covering around said fuse element portion(s) (5). The fuse box device according to claim 1 or 2, wherein said at least one output terminal (4) comprises a plurality of output terminals and said fuse box (21) contains at least one integrally formed insulator partition wall (23) such as to define a plurality of enclosures (S1), so that each of said enclosures (S1) contains said output terminal (4) connectable to a press-fit terminal of one of electrical cables which constitute said wire harness. The fuse box device according to any one of claims 1 to 3, wherein said fuse box (21) comprises at least one holder means (23, 25, 26, 46) for defining a specific fixing position for said fuse unit (1) and fixing said fuse unit (1) in said fuse box (21) by sandwiching a part of said fuse unit (1) by said holder means. The fuse box device according to claim 4, wherein said fuse box (21) comprises two opposing inner faces, said insulator partition wall(s) (23) has/have a top portion, and said fuse box device further comprises a cover joint (43) having an inner face, wherein said at least one holder means is selected from the group consisting of: at least one slit (25) formed in said insulator partition wall(s) (23) such as to extend from said top portion thereof to a half-way point downwards; two pairs of ribs (26) formed in said opposing inner faces of said fuse box (21) at positions corresponding to those of said slit(s) (25); and two pairs of ribs (46) formed in said inner face of said cover joint (43) at positions corresponding to those of said slit(s) (25). The fuse box device according to claim 4 or 5, wherein said part of said fuse unit (1) comprises said insulator-molded portion (7).

Inventors: SUMIDA TATSUYA, TAGA SHUNJI, SUMIDA, TATSUYA, TAGA, SHUNJI, Sumida, Tatsuya, Sumitomo Wiring Syst., Ltd., Taga, Shunji, c/o Sumitomo Wiring Systems, Ltd.
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 2000
Main classification: H01H85
IPC codes: H01H69, H01H85