Fuse link unit

Abstract

Fuse link unit (70) which can be connected directly to a battery (100), wherein: a busbar (30) comprising: a band plate portion (31) provided in a central portion of the busbar (30); Tabs (40) provided at both end edges of the band plate portion (31), the length of the tabs (40) corresponding to the entire width of the band plate portion (31), and the tabs (40) being provided substantially perpendicular to the band plate portion (31); and two fuse circuit forming parts (32A, 32B) each mounted adjacent to two side edges of the band plate portion (31), and two electrically insulating housings (42A, 42B), each provided by insert molding on one of the fuse circuit forming parts (32A, 32B), wherein the band plate portion (31), the tabs (40) and the two fuse circuit forming parts (32A, 32B) are formed in one piece, the two fuse circuit forming parts (32A, 32B) and the two housings (42A, 42B) are bent in the same direction along the two side edges of the band plate section (31) so that a rectangular support is formed when the two fuse circuit forming parts (32A, 32B) and the two housings (42A, 42B) are viewed from above with the band plate section (31), and the fuse circuit forming parts (32A, 32B) are arranged side by side, respectively, with a space equal to the width of the band plate portion (31) therebetween.

Description

BACKGROUND OF THE INVENTION1. FIELD OF THE INVENTIONThe present invention relates to a fuse link unit directly connected to a vehicle battery without a cable.2. DESCRIPTION OF THE PRIOR ARTA conventional fuse link is described in Japanese Patent Laid-Open Publication No. 2004-18606.FIG. 1 shows a bus bar of the conventional fuse link described in the above-mentioned document.This fuse box comprises a flat plate-like bus bar 11 which is electrically conductive and a pair of insulation housings (not shown). The bus bar 11 has fuse circuit forming parts 13A and 13B (which form a heavy current fuse circuit) and are integrally provided with each other on opposite sides of a band plate portion (bent portion) 12 disposed substantially in the central portion of the bus bar 10. The housings are respectively integrally formed on the pair of fuse circuit forming members 13A, 13B by insert molding a synthetic resin. The band plate portion 12 is bent so that the pair of housings are arranged in parallel and opposite to each other, thereby forming the fuse block.Two pairs of grooves 12a are formed substantially in the center portion of the base plate portion 12 by pressing, and extend in the up-down direction, the two pairs of grooves 12a being spaced apart from each other by a predetermined distance. The base plate portion 12 can be easily bent inward along the pair of grooves 12 a. A generator terminal portion 19 is formed by bending, and is located substantially at the center portion of the base plate portion 12.The fuse circuit forming part 13A includes the elongated and narrow connecting plate portion 14 having a rectangular shape extending from a side edge of the band plate portion 12 at an upper end portion thereof, a plurality of screw fastening terminal portions 16 chain-connected to this connecting plate portion 14 through respective fuse elements (fuse portions) 15 and extending in the side direction, a battery terminal portion 17 directly (i.e., not via the fuse portion) connected to one end of the connecting plate portion 14 remote from the band plate portion 12 and extending in the side direction, and a fuse portion 18 (for a generator circuit) provided at the other end portion of the connecting plate portion 14 and extending in the longitudinal direction.The other fuse circuit forming member 13B comprises the elongated and narrow connecting plate portion 14 of rectangular shape extending from the other side edge of the band plate portion 12 at the upper end portion thereof, and a plurality of screw fastening terminal portions 16 connected in a chain manner in this connecting plate portion 14 via respective fuse elements 15. These fuse elements 15, 18 burn out when an electric current above a predetermined value flows therethrough.The housings integrally formed on the pair of fuse circuit forming members 13A, 13B by insert molding a synthetic resin cover the entire fuse circuit forming member 13A, 13B except for the band plate portion 12, the fuse elements 15, 18, and the periphery of the screw fixing holes 16a, 17a, 17b of the terminal portions 16, 17. in the above fuse insert unit, the fuse circuit forming members 13A, 13B are bent in the same direction from both side ends so that the fuse circuit forming members 13A, 13B are arranged in parallel to each other with a predetermined distance therebetween. However, when the fuse circuit forming members 13A, 13B are bent, the tape plate portion itself takes an unexpected bulge outward. Therefore, the distance between the fuse circuit forming parts 13A, 13B is not constant, and then the quality of the fuse link unit is impaired.In the fuse link unit described in the above-mentioned document, the groove 12a is formed by pressing a predetermined line along which the fuse circuit forming parts 13A, 13B are provided. However, the cross section of the pressurized portion of the groove decreases, and this decrease is disadvantageous in terms of the electric conduction capacity.JP 2000-182 506 A discloses a fuse link unit which is made of a plurality of parts to be individually assembled. DE 103 56 754 A1 describes a fusible link insert which comprises many structural elements forming a fusible circuit, which each comprise a plurality of terminal sections which are arranged in the form of chains, and which are each connected to a connecting section via fusible link sections. DE 199 38 068 C2 describes a power distribution center (PDC), such as is used in the electrical system of a motor vehicle. This includes means for pivotally connecting a power supply terminal to the PDC such that pivotal movement of the terminal relative to a housing of the PDC inserts the terminal into an opening formed in the housing and into contact with a bus bar held in the housing. U.S. Pat. No. 7,071,808 B2 discloses a securing connection unit with screw fastening sections. EP 1 406 282 A2 describes a fuse link unit having a plurality of socket portions.SUMMARY OF THE INVENTIONIn view of the above circumstances, it is an object of the present invention to provide a fuse link unit which has a bus bar that can be properly bent at any required location without forming a groove along a bending line on both sides of a band plate portion and therefore can contribute to improving quality.The invention is defined by claim 1.The above configuration makes it possible to increase the bending rigidity of the band plate portion because the both end edges of the band plate portion are each provided with one of the flanges that is as long as the entire width of the band plate portion. This makes it possible to prevent the band plate portion from being unnecessarily deflected outward when the fuse circuit forming members are bent along the both side edges of the band plate portion. By preventing the band plate portion from being deformed unnecessarily, it is possible to arrange the two bodies each consisting of one of the fuse circuit forming members and one of the housings side by side with a sufficient clearance therebetween, thereby improving the quality. As a result, since the fuse circuit forming members can be bent at the proper location without any trouble, it becomes unnecessary to provide measures such as forming grooves in the both side edges of the tape plate portion for the purpose of facilitating the bending of the fuse circuit forming members there. This makes it possible to avoid a disadvantage (a reduction in the current conduction capacity) which would otherwise occur as a result of reduced cross sections of electrically conductive channels if grooves were provided there.In addition to the above configuration, each of the two fuse circuit forming members may include: a connection plate portion; first fuse elements connected to the connection plate portion; and load terminal terminal portions connected to the two fuse circuit forming members via one of the first fuse elements, respectively. One of the two fuse circuit forming members may further include a second fuse member; and a battery terminal connecting portion connected to the second fuse member with the connecting plate portion and directly connected to the battery.Furthermore, the fuse-insert unit can have covers with which exposed portions of the busbar are covered.The free ends of the two bodies may have first and second engaging portions which are engaged with each other.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a perspective view showing a bus bar of a conventional type fuse-insert unit. FIG. 2 is a plan view showing a configuration of a bus bar that is a component of a fuse link unit according to an embodiment of the present invention in the process of molding. FIG. 3 is a view of the bus bar taken along the line III-III indicated by an arrow in FIG. 2. FIG. 4 is a view of the bus bar taken along the line IV-IV indicated by the other arrow in FIG. 2. FIG. 5 is a perspective view showing how housings made of resin are attached to the bus bar shown in FIG. 2 by insert molding. FIG. 6 shows the bus bar and the housing of FIG. 5 in a top view. FIG. 7 is an exploded perspective view of the fuse link unit according to the present invention formed by bending parts shown in FIG. 5. FIG. 8 is a perspective view showing how the fuse link unit according to the present embodiment is used.DETAILED DESCRIPTION OF THE EMBODIMENTHereinafter, a description will be given of an embodiment of the present invention with reference to the drawings.A fuse-insert unit 70 shown in FIGS. 2 to 7 includes: a bus bar 30; resin-made housings 42A and 42B which are respectively insert-molded to predetermined portions in the bus bar 30; and resin-made covers 61 to 64 which are provided to cover exposed portions of the bus bar 30.As shown in FIGS. 2 to 4, the bus bar 30 is formed by press-forming an electrically conductive plate. A band plate portion 31 and two fuse circuit forming members 32A and 32B are integrally formed on the bus bar 30 by arranging the band plate portion 31 at the center, and the two fuse circuit forming members 32A and 32B are continuously continuously formed continuously to two sides of the band plate portion 31, and the fuse circuit forming members 32A and 32B are bent along the two side ends 31 aof the band plate portion 31 in the same direction while being arranged side by side with a clearance therebetween equal to the width of the band plate portion 31.A battery terminal terminal portion 35 and a generator terminal terminal portion 37 are provided at the upper end of a fuse circuit forming member 32A which is one of the two fuse circuit forming members. The battery terminal terminal portion 35 and the generator terminal terminal portion 37 are formed so that the respective rectangular extending parts are bent at right angles to the fuse circuit forming part 32A but in opposite directions. The battery terminal connection portion 35 is directly connected to a battery. The generator terminal connection portion 37 is connected to a generator. A hole 35a for passing a bolt is provided at the battery terminal terminal portion 35, whereas a recess 37a for passing a bolt is provided at the generator terminal terminal terminal portion 37.A connection plate portion 33 and a power supply plate 34 are set and provided in this fuse circuit forming part 32A, and the connection plate portion 33 and the power supply plate 34 are connected to each other via a fuse element 36. The connection plate portion 33 has the generator terminal connection portion 37 in its upper portion. This connecting plate portion 33 is continuously formed from a corresponding one of the both side ends 31a of the band plate portion 31. The power supply plate 34 has the battery terminal connection portion 35 in its upper portion. This power supply plate 34 is separated from the band plate portion 31. Further, the power supply plate 34 and the connection plate portion 33 are connected to each other only by the securing member 36, and the other parts of the power supply plate 34 are formed separately from the other parts of the connection plate portion 33. Further, load terminal terminal portions 39 are provided in a chain-like manner in the lower end edge of the connection plate portion 33, the load terminal portions 39 being connected to the connection plate portion 33 via their respective securing member 38.Further, the other fuse circuit forming member 32B is provided with load terminal terminal portions and terminal portions 39a in a chain-like manner in the lower end edge of the other connection plate portion 33 which is continuously formed from the other side edge 31a of the band plate portion 31. The load terminal terminal portions 39 are connected to the lower end edge of the fuse circuit forming member 32B with their respective fuse element 38, while the terminal portion 39a is connected thereto without a fuse element.Further, the band plate portion 31 is formed as a rectangle having a predetermined width. Flanges 40 are provided at the upper and lower end edges 31b of the band plate portion 31 bent in the thickness direction of the plate of the band plate portion 31, these flanges 40 being as long as the entire width of the band plate portion 31. Although the width of each of the parts of the respective flanges 40 protruding from the upper and lower end edges is small, each of the parts plays a role of a rib for increasing the flexural rigidity of the band plate portion 31.As shown in FIGS. 5 and 6, housings 42A and 42B each made of an electrically insulating resin are fixed to the fuse circuit forming part 32A and 32B by insert molding while exposing required parts of each of the housings 42A and 42B to the outside. Therefore, two bodies 50A and 50B constituting the fuse cartridge are each composed of one of the fuse circuit forming parts 32A and 32B and one of the housings 42A and 42B. Free ends of these bodies 50A and 50B are respectively provided with second and first engaging portions 52 and 51 which are engaged with each other so that the free ends are fastened to each other by the engagement.Note that housing portions for constituting a connector are respectively provided in the lower end portions of the housings 42A and 42B. The housing portions serve as connectors 49 which can be detachably engaged with the counterpart connectors of the connectors 49 by arranging the terminal portions 39 and 39a in the housing portions.When this fuse-insert unit 70 is to be manufactured, first, the band plate portion 31 is disposed substantially at the center portion of a metal plate material in the form of a flat plate. Then, the bus bar 30 is formed by being punched out such that the fuse circuit forming parts 32A and 32B constituting the fuse circuits are disposed on the both sides of the tape plate portion 31. Then, the housings 42A and 42B are integrally molded on the fuse circuit forming parts 32A and 32B, respectively, by insert molding a synthetic resin. Thereby, bodies 50A and 50B are formed.Then, as shown in FIGS. 5 and 6, the two bodies 50A and 50B are respectively bent along the two end edges 31 aof the band plate portion 31 so as to provide a square support when the band plate portion 31 is viewed from above and the two bodies 50A and 50B are disposed, the two bodies 50A and 50B being disposed in parallel with each other. Note that the direction in which the two bodies 50A and 50B are bent is indicated by an arrow Y. Thereafter, as shown in FIG. 7, the first and second engagement portions 51 and 52, respectively, provided at the free ends of the bodies 50A and 50B are locked to each other, and exposed portions of the bus bar 30 are covered by the covers 61 to 64. The safety insert unit 70 is thus completed.As shown in FIG. 8, when this fuse box unit 70 is to be attached to the battery, first, a starter cable terminal (not shown) and a battery terminal 102 are fastened to the battery terminal connection portion 35 using a bolt 82 and a nut 83. Then, the battery terminal 102 is connected to an electrode post 101 of the battery 100. As a result, the fuse link unit 70 is directly connected to the battery 100. Then, a generator terminal 110 is fastened to the generator terminal connection portion 37 using a bolt 81 and a nut. Then, the connectors 49 are respectively connected to their counterpart connectors (not shown). This completes the wiring.These connections distribute and supply the power supplied from both the battery 100 and the generator to the loads via the fuse circuits formed by the fuse circuit forming parts 32A and 32B. When the power supplied from the battery 100 becomes insufficient, the battery 100 is charged by causing the generator to supply power to the battery 100. When an electric current flows to one of the fuse elements 36 and 38 having a magnitude larger than a predetermined magnitude due to a short circuit and the like in the loads, one of the fuse elements 36 and 38 through which the higher electric current flows is heated and blown. This prevents a fault due to the excessively high current.As described above, this fuse link unit 70 can be manufactured by the simple process of only bending the two bodies 50A and 50B along the two end edges 31 aof the band plate portion 31 of the bus bar 30. This makes it possible to manufacture small-sized fuse packages 70 in large quantities at low cost.A single bus bar 30 allows the same number of fuse circuits as previously required two bus bars 30 to be fully secured. This enables the bus bar 30 to be laid in a smaller and compact manner in response to an increased number of integrated circuits.Since the both end edges 31 bof the band plate portion 31 are each provided with one of the flanges 40 that are each as long as the entire width of the band plate portion 31, the bending rigidity of the band plate portion 31 is increased. For this reason, when the fuse circuit forming parts 32A and 32B are bent along the both end edges 31 aof the band plate portion 31, the flanges enable to prevent the band plate portion 31 from being unnecessarily deflected outward.By preventing unnecessary deformation of the band plate portion 31, it is possible to dispose the bodies 50A and 50B each consisting of one of the fuse circuit forming parts 32A and 32B and one of the housings 42A and 42B side by side with a sufficient clearance therebetween. This makes it possible to improve the quality. Since the bus bar 30 can be bent along the proper locations without difficulty, the fuse box unit 70 does not need to provide a groove in both side edges of the band plate portion 31 for the purpose of facilitating the bending, unlike the conventional type fuse box unit. This makes it possible to avoid a disadvantage (a decrease in the current conduction capacity) that would otherwise occur due to the decreased cross section of the electrically conductive channels if the grooves were provided.Moreover, if the electrically conductive bus bar 30 were exposed to the outside, the bus bar 30 would be undesirably short-circuited. However, the exposed portions of the bus bar 30 are covered by the covers 61 to 64. This cover makes it possible to securely prevent the bus bar 30 from being accidentally short-circuited, thus enhancing safety.Moreover, since the free ends of the bodies 50A and 50B can be securely fastened to each other by mutually locking the first engagement portion 51 and the second engagement portion 52, the rigidity of the fuse link unit 70 can be increased.The foregoing embodiment has been described in the case where the two fuse circuit forming members 32A and 32B are connected to the individual tape plate portions 31 so that the two bodies 50A and 50B are arranged in parallel. However, it is to be noted that three or more bodies may be arranged in parallel by additionally providing fuse circuit forming members using tape plate portions of the same kind.Also in this case, the provision of the flanges at the upper and lower end edges of each of the additionally provided band plate portions makes it possible to prevent unnecessary deformation of the band plate portions and hence to improve the quality.

Claims

A fuse-insert unit (70) directly connectable to a battery (100), comprising: a bus bar (30) comprising: a band plate portion (31) provided in a central portion of the bus bar (30); tabs (40) provided at both end edges of the band plate portion (31), wherein the length of the tabs (40) corresponds to the entire width of the band plate portion (31), and the tabs (40) are provided substantially perpendicular to the band plate portion (31); and two fuse-circuit forming members (32A, 32B) respectively attached adjacent to two side edges of the band plate portion (31), and two electrically insulating housings (42A, 42B) respectively provided by insert molding on one of the fuse-circuit forming members (32A, 32B), wherein the band plate portion (31), the tabs (40) and the two fuse circuit forming members (32A, 32B) are integrally formed, the two fuse circuit forming members (32A, 32B) and the two housings (42A, 42B) are bent along the two side edges of the band plate portion (31) in the same direction, so that when the two fuse circuit forming members (32A, 32B) and the two housings (42A, 42B) are viewed from above with the band plate portion (31), a rectangular support is given, and the fuse circuit forming members (32A, 32B) are arranged side by side with a space equal to the width of the band plate portion (31) therebetween.The fuse cartridge unit (70) according to claim 1, wherein each of the two fuse circuit forming members (32A, 32B) comprises: a connection plate portion (33); first fuse elements (38) connected to the connection plate portion (33); and load terminal portions (39) connected to the connection plate portion (33) via the respective first fuse elements (38), and one of the two fuse circuit forming members (32A, 32B) further comprises: a second fuse element (36); and a battery terminal terminal portion (35) connected to the connection plate portion (33) via the second fuse element (36), the battery terminal terminal portion (35) being directly connectable to the battery (100).The fuse cartridge unit (70) according to claim 1, further comprising covers (61-64) with which exposed portions of the bus bar (30) are covered.The fuse bit unit (70) according to claim 1, wherein free ends of the two housings (42A, 42B) are provided with first (51) and second (52) engaging portions, respectively, which engage with each other, and when the two housings (42A, 42B) are bent, the free ends of the two housings (42A, 42B) are fixed to each other by the mutual engagement of the first (51) and second (52) engaging portions.The fuse link unit (70) of claim 1, wherein the tabs (40) are not perforated.The fuse cartridge unit (70) according to claim 1, wherein one of the fuse circuit forming members (32A, 32B) comprises a connection plate portion (33) and a power supply plate (34) connected to the connection plate portion (33) via a single fuse element (6).The fuse cartridge unit (70) according to claim 6, wherein the one of the fuse circuit forming members (32A, 32B) further comprises a battery terminal connecting portion (35) connected to the power supply plate (34).The fuse cartridge unit (70) according to claim 2, wherein the one of the fuse circuit forming members (32A, 32B) further comprises a terminal portion (39a) directly connected to the connection plate portion (33) without a fuse element.The fuse cartridge unit (70) according to claim 2, wherein the battery terminal connection portion (35) is not connected to the connection plate portion (33) or one of the first fuse elements (38) except via the second fuse element (36).The fuse cartridge unit (70) according to claim 2, wherein the battery terminal connection portion (35) is connected to the second fuse element (36) via a power supply plate (34).

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