Fusible link unit

Disclosed is a fusible link unit which is capable of being directly connected to a battery, and which includes: a band plate portion integrally formed in a bus bar; two fuse circuit-forming members contiguously formed respectively to two sides of the band plate portion; and bodies each including an electrically insulating housing formed onto a corresponding one of the fuse circuit-forming members by insert molding. Flanges as long as the entire width of the band plate portion are formed respectively in two end edges of the band plate portion by bending the flanges from the two end edges in the plate thickness direction. The bodies are arranged side-by-side with a clearance equal to the width of the band plate portion by bending the bodies along the two side edges of the band plate portion in the same direction.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-212917 filed on Aug. 4, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a fusible link unit directly connected with a battery for vehicles without a cable.

2. Description of the Related Art

A conventional fusible link is shown in Japanese Patent Application Laid-Open Publication No. 2004-186006.

FIG. 1shows a bus bar of the conventional fusible link disclosed in the above reference.

This fusible link comprises a flat plate-like bus bar11of an electrically conductive nature, and the pair of insulating housing (not shown). The bus bar11has fuse circuit-forming members13A and13B (which form large-current fuse circuit) integrally formed respectively at opposite sides of a band plate portion (bending portion)12formed generally at a central portion of the bus bar11. The housings are formed integrally respectively on the pair of fuse circuit-forming members13A,13B by insert molding a synthetic resin. The band plate portion12is bent in such a manner that the pair of housings is disposed in parallel and opposed to each other, thereby forming the fusible link.

Tow pair of grooves12aare formed at a generally central portion the base plate portion12by pressing, and extend in an upward-downward direction, the two pair of grooves12abeing spaced a predetermined distance from each other. The base plate portion12can be easily bent inwardly along the pair of grooves12a. An alternator terminal portion19is form by bending and is located at the generally central portion of the base plate portion12.

The fuse circuit-forming member13A includes the elongate and narrow interconnecting plate portion14of a rectangular shape extending from one side edge of the band plate portion12at an upper end portion thereof, a plurality of screw-fastening terminal portions16which are connected to this interconnecting plate portion14in a chain-like manner through respective fuse elements (fusible portions)15, and extend in a transverse direction, one battery terminal portion17which is connected directly (that is, not through the fusible portion) to one end of the interconnecting plate portion14remote from the band plate portion12, and extends in the transverse direction, and fusible portion18(for an alternator circuit) which is formed at the other end portion of the interconnecting plate portion14, and extends in the longitudinal direction.

The other fuse circuit-forming member13B includes the elongate and narrow interconnecting plate portion14of a rectangular shape extending from the other side edge of the band plate portion12at the upper end portion thereof, and a plurality of screw-fastening terminal portion16which are connected to this interconnecting plate portion14in a chain-like manner through respective fuse elements15. These fuse elements15,18are blown when an electric current over a predetermined value flows therein.

The housings, which are formed integrally respectively on the pair of fuse circuit-forming members13A,13B by insert molding a synthetic resin, cover the whole of the fuse circuit-forming member13A,13B except of the band plate portion12, fuse elements15,18, periphery of screw-fastening holes16a,17a,17bof the terminal portions16,17.

According to the fusible link unit described above, the fuse circuit-forming members13A,13B are bent from both side ends in the same direction so that the fuse circuit-forming members13A,13B will be disposed in parallel with a predetermined distance. However, when the fuse circuit-forming members13A,13B are bent, the band plate portion itself comes to unexpectedly warp outwardly Consequently, distance between the fuse circuit-forming members13A,13B does not become constant, and then quality of the fusible link unit comes to degenerate.

According to the fusible link unit disclosed in the same references the groove12ais formed by pressing on a predefined line along which the fuse circuit-forming members13A,13B. However, a cross section of the pressed area of the groove will decrease, and thus this decrease is disadvantage in view of a current-carrying capacity.

SUMMARY OF THE INVENTION

With the above-described conditions taken into consideration, an object of the present invention is to provide a fusible link unit which includes a bus bar capable of being adequately bent in any locations required without forming any groove along a bending line on the two sides of a band plate portion, and which can accordingly make contributions to improving the quality.

An aspect of the present invention is to provide a fusible link unit which is capable of being directly connected to a battery, and which includes a bus bar and two bodies. The bus bar includes: a band plate portion provided in a central portion of the bus bar; flanges provided respectively in two end edges of the band plate portion, the flanges being as long as an entire width of the band plate portion, and the flanges provided virtually perpendicularly to the band plate portion; and two fuse circuit-forming members consecutively installed respectively to two side ends of the band plate portion. Each of the two fuse circuit-forming members includes an interconnecting plate portion, first fuse elements connected to the interconnecting plate portion, and load connecting terminal portions connected to the interconnecting plate portion via the respective first fuse elements. Each of the two bodies has an electrically insulating housing formed on a corresponding one of the fuse circuit-forming members by insert molding. One of the two fuse circuit-forming member further includes: a second fuse element; and a battery terminal connecting portion connected to the interconnecting plate portion via the second fuse element, the battery terminal connecting portion directly connected to the battery. The band plate portion, the flanges and the two fuse circuit-forming members are integrally formed. The two fuse circuit-forming members and the two bodies are bent along the two side edges of the band plate portions in the same direction, and a flat vision of the two fuse circuit-forming members and the two bodies as well as the band plate portion forms a right square bracket. Thereby, the fuse circuit-long members are arranged side-by-side with a clearance equal to the width of the band plate portion.

The foregoing configuration makes it possible to increase the bending rigidity of the band plate portion because the two end edges of the band plate portion are provided with the respective flanges which are as long as the entire width of the band plate portion. This makes it possible to prevent the band plate portion from unnecessarily defecting outward when the fuse circuit-forming members are bent along the two side edges of the band plate portion. The preventing of the band plate portion from unnecessarily deforming makes it possible to arrange the two bodies, each configured of one of the fuse circuit-forming members and one of the housings, side-by-side with an adequate clearance interposed in between, and to thus improve the quality. Moreover, because the fuse circuit-forming members are capable of being bent in the adequate position without trouble, this makes it unnecessary to take measures such as forming grooves in the two side edges of the band plate portion for the purpose of helping to bend the fuse circuit-forming members there easily. This makes it possible to avoid a disadvantage (decrease in current-forming capacity) which would otherwise occur due to decreased cross-sections of electrically conductive channels when grooves were formed there.

In addition to the foregoing configuration each of the two fuse circuit-forming members may include: a interconnection plate portion; first fuse elements connected to the interconnecting plate portion; and load connecting terminal portions connected to the two fuse circuit-forming member via the first fuse elements, respectively. One of the two fuse circuit-forming members may further include a second fuse element; and a battery terminal connecting portion which is connected to the interconnecting plate portion with the second fuse element, and which is directly connected to the battery.

Furthermore, the fusible link unit may include covers with which exposed portions of the bus bar are covered.

Free ends respectively of the two bodies may include first and second engagement portions which engage with each other.

DETAILED DESCRIPTION OF THE EMBODIMENT

Descriptions will be provided hereinafter for an embodiment of the present invention with reference to the drawings.

A fusible link unit70shown inFIGS. 2 to 7includes: a bus bar30; resin-made housings42A and42B fitted respectively to expected portions in the bus bar30by insert molding; and resin-made covers61to64provided to cover exposed portions of the bus bar30.

As shown inFIGS. 2 to 4, the bus bar30is formed by press-molding an electrically conductive plate. A band plate portion31and two fuse circuit-forming members32A and32B are integrally formed on the bus bar30by placing the band plate portion31in the center, and by forming the two fuse circuit-forming members32A and32B contiguously to two sides of the band plate portion31and bending the fuse circuit-forming members32A and32B along the two respective side ends31aof the band plate portion31in the same direction while arranged side-by-side with a clearance equal to the width of the band plate portion31.

A battery terminal connecting portion35and an alternator terminal connecting portion37are provided to the upper end of a fuse circuit-forming member32A which is one of the two fuse circuit-forming members. The battery terminal connecting portion35and the alternator terminal connecting portion37are formed by bending the respective rectangular extended pieces at a right angle to the fuse circuit-forming member32A but in opposite directions. The battery terminal connecting portion35is directly connected to a battery. The alternator terminal connecting portion37is connected to an alternator. A hole35athrough which to penetrate a bolt is provided to the battery terminal connecting portion35whereas a notch37athrough which to penetrate a bolt is provided to the alternator terminal connecting portion37.

A interconnecting plate portion33and a power supply plate34are defined and formed in this fuse circuit forming member32A, and the interconnecting plate portion33and the power supply plate34are connected to each other with a fuse element36. The interconnecting plate portion33has the alternator terminal connecting portion37in the upper portion thereof his interconnecting plate portion33is formed while continuing from a corresponding one of the two side ends31aof the band plate portion31. The power supply plate34has the battery terminal connecting portion35in the upper portion thereof. This power supply plate34is separated from the band plate portion31. In addition) the power supply plate34and the interconnecting plate portion33are connected to each other with the Use element36only, and the other parts of the power supply plate34are separated from the other parts of the interconnecting plate portion33. Furthermore, load connecting terminal portions39are formed in a chain-like manner in the lower end edge of the interconnecting plate portion33while the load connecting terminal portions39are connected to the interconnecting plate portion33with their respective fuse elements38.

Moreover, the other fuse circuit-forming member32B is provided with load connecting terminal portions39and terminal portions39ain a chain-like manner in the lower end edge of the other interconnecting plate portion33formed while continuing from the other side edge31aof the band plate portion31. The load connecting terminal portions39are connected to the lower end edge of the fuse circuit-forming member32B with their respective fuse elements38whereas the terminal portion39ais connected thereto with no fuse element.

Additionally, the band plate portion31is formed as a rectangle with a predetermined width. Flanges40are formed respectively in the upper and lower end edges31bof the band plate portion31while bent in a direction of the plate thickness of the band plate portion31. These flanges40are as long as the entire width of the band plate portion31. Although the width of each of parts of the respective flanges40which jut out from the upper and lower end edges is small, each of the parts plays a role of a rib for increasing the bending rigidity of the band plate portion31.

As shown inFIGS. 5 and 6, housings42A and42B each made of an electrically insulating resin are fitted respectively to the fuse circuit-forming member32A and32B by insert molding while required parts of each of the housings42A and42B are exposed to the outside. Thereby; two bodies50A and50B constituting the fusible link are configured of the fuse circuit-forming members32A and32as well as the housings42A and42B, respectively. Free ends of these bodies50A and50B are provided respectively with second and first engagement portions52and51which engage with each other so that the engagement fixes the free ends to each other.

It should be noted that housing portions each for constituting a connector are formed respectively in the lower end portions of the housings42A and42B. The housing portions serve as connectors49capable of detachably engaging with counterpart connectors of the connectors49by placing the terminal portions39and39ain the housing portions.

When this fusible link unit70is going to be manufactured, first of all, the band plate portion31is placed in a virtually central portion of a metal-made plate material in a flat plate shape. Subsequently, the bus bar30is formed by stamping in a way that the fuse circuits forming members32A and32B constituting the fuse circuits are arranged respectively on the two sides of the band plate portion31. Thereafter, the housings42A and42B are respectively formed integrally onto the fuse circuit-forming members32A and32B by insert molding a synthetic resin. Thereby the bodies50A and50B are formed.

Afterward as shown inFIGS. 5 and 6, the two bodies50A and50B are bent respectively along the two end edges31aof the band plate portion31in a way that a flat vision of the band plate portion31and the two bodies50A and50B forms a right square bracket while the two bodies50A and50B are in parallel with each other. It should be noted that the direction in which the two bodies50A and50B are bent is shown by an arrow Y. After that, as shown inFIG. 7, the first and second engagement portions51and52provided respectively to the free ends of the bodies50A and50B are locked with each other, and exposed portions of the bus bar30are covered with the covers61to64. Thereby, the fusible link unit70is completed

As shown inFIG. 8, in a case where this fusible link unit70is going to be attached to the battery, first of all, a starter cable terminal (its illustration is omitted) and a battery connecting terminal102are both fastened to the battery terminal connecting portion35by use of a bolt82and a nut83. Subsequently, the battery connecting terminal102is connected to an electrode post101of the battery100. By this, the fusible link unit70is directly connected to the battery100. Thereafter, an alternator terminal110is fastened to the alternator terminal connection portion37by use of a bolt81and a nut. Afterward, the connectors49are connected to their respective counterpart connectors (their illustrations are omitted). Thereby, the wiring is completed.

These connections distributes and supplies the power, which is supplied from each of the battery100and the alternator, to the loads via the fuse circuits constituted by the fuse circuit-forming members32A and32B. If the power supplied from the battery100runs short, the battery100is charged by causing the alternator to supply the power to the battery100. If an electrical current flows to one of the fuse elements36and38in an amount larger than a predetermined amount because of a short circuit or the like in the loads, one of the fuse elements36and38to which the larger amount of electrical current flows is heated and fused. This prevents an accident from occurring due to the overcurrent.

As described above, this fusible link unit70can be manufactured by the simple work of nothing but bending the two bodies50A and50B respectively along the two end edges31aof the band plate portion31of the bus bar30. This makes it possible to manufacture small-sized fusible link units70in large quantities with lower costs.

A single bus bar30makes it possible to fully secure the same number of fuse circuits as two bus bars30have. This makes it possible for the bus bar30to be laid out in a miniaturized and space-saving manner in response to an increased number of integrated circuits.

Because the two end edges31bof the band plate portion31are provided respectively with the flanges40each as long as the entire width of the band plate portion31, the bending rigidity of the band plate portion31is increased. For this reason, when the fuse circuit-forming member32A and32B are bent along the two end edges31aof the band plate portion31, the flanges make it possible to prevent the band plate portion31from unnecessarily deflecting outward.

The prevention of the band plate portion31from unnecessarily deforming makes it possible to arrange the bodies50A and50B, which are configured respectively of the fuse circuit-forming member32A and32B as well as the housings42A and42B, side-by-side with an, adequate clearance in between This makes it possible to enhance the quality. Because the bus bar30is capable of being bent along the adequate places without trouble, the fusible link unit70requires no groove to be formed in the two side edges of the band plate portion31for the purpose of facilitating the bending, unlike the fusible link unit of the conventional, type. This makes it possible to avoid a disadvantage (decrease in current-carrying capacity) which would otherwise occur due to decreased cross-sections of the electrically conductive channels when the grooves are formed.

In addition, if the electrically conductive bus bar30would be exposed to the outside) the bus bar30would be short-circuited unnecessarily However, the exposed portions of the bus bar30are covered with the covers61to64. This coverage makes it possible to securely prevent the bus bar30from being unnecessarily short-circuited, and to thus improve the safety.

Furthermore, because the free ends of the bodies50A and50B are capable of being securely fixed to each other by locking the first engagement portion51and the second engagement portion52with each other, the rigidity of the fusible link unit70is capable of being increased.

The foregoing embodiment has been described citing the case where the two Use circuit-forming members32A and3213are connected to the single band plate portion31so that the two bodies50A and50B are arranged in parallel. It should be noted, however, that three or more bodies are capable of being arranged in parallel by additionally arranging fuse circuit-forming members by use of band plate portions of the same type.

In this case, too, the providing of the flanges respectively to the upper and lower end edges of each of the additionally-arranged band plate portions makes it possible to prevent the band plate portions from unnecessarily deforming, and to thus improve the quality.