IN-VEHICLE-COMPONENT CIRCUIT UNIT

An in-vehicle-component circuit unit includes a circuit constituent member, a case, a connection bus bar including an internal connection portion and an external connection portion, a first window portion facing the internal connection portion and a first bolt insertion hole in the case, and a second window portion facing the external connection portion and a second bolt insertion hole in the case, The first bolt insertion hole and the second bolt insertion hole are each sized to include a tolerance absorbing gap, the connection bus bar is accommodated so as to be displaceable relative to the case in a tolerance absorbing direction, the first window portion is open with a size that enables a bolt fastening operation to be performed through the first window portion, and the second window portion is open with a size that enables a bolt fastening operation to be performed through the second window portion.

TECHNICAL FIELD

The present disclosure relates to an in-vehicle-component circuit unit.

BACKGROUND

JP 2012-243449A discloses a structure including a circuit unit, such as a junction box, housed in a casing of a battery pack, which is an in-vehicle component configured to be mounted in a vehicle, together with a battery module and a battery control system. In the structure employed here, in order to enable the circuit unit housed in the casing of the battery pack to be connected to an external device, a connector to which an external counterpart connector is to be connected is provided on a peripheral wall of the casing, and the connector and the circuit unit are conductively connected to each other using relay components such as a coated wire and a bus bar.

The structure of JP 2012-243449A requires relay components such as a coated wire and a bus bar to provide a connection between the connector provided on the casing and an external connection portion provided in the circuit unit housed in the casing, and therefore inherently faces the problems of a large component count and poor handleability. In addition, when the circuit unit is a junction box or the like housed in the casing of a high voltage component such as a battery pack, as in the case of JP 2012-243449A, the relay components and the external connection portion of the circuit unit become current-carrying portions. Accordingly, there is also a need to separately provide protection against electric shock hazards. This results in a complex structure for connecting the external connection portion of the in-vehicle-component circuit unit to the connector provided in the casing of the in-vehicle component, thus inevitably reducing the workability.

Therefore, there is disclosed an in-vehicle-component circuit unit that can achieve a simplified connection structure between an external connection portion of the in-vehicle-component circuit unit and a connector provided in a casing of an in-vehicle component, as well as improved connection workability.

SUMMARY

An in-vehicle-component circuit unit according to the present disclosure is an in-vehicle-component circuit unit configured to be housed in a casing of an in-vehicle component, including: a circuit constituent member; an insulating case accommodating the circuit constituent member; a connection bus bar accommodated in the case and including an internal connection portion configured to be conductively connected to a circuit-side connection portion provided in the circuit constituent member, and an external connection portion configured to be conductively connected to a connector-side connection portion of a connector provided on the casing; a first window portion provided in the case and disposed facing the internal connection portion of the connection bus bar and a first bolt insertion hole provided in the internal connection portion; and a second window portion provided in the case and disposed facing the external connection portion of the connection bus bar and a second bolt insertion hole provided in the external connection portion, wherein the first bolt insertion hole and the second bolt insertion hole are each sized to include a tolerance absorbing gap extending in a tolerance absorbing direction, the connection bus bar is accommodated so as to be displaceable relative to the case in the tolerance absorbing direction, the first window portion is open with a size that enables a bolt fastening operation to be performed from an exterior of the case to the circuit-side connection portion of the internal connection portion through the first window portion, and the second window portion is open with a size that enables a bolt fastening operation to be performed from the exterior of the case to the connector-side connection portion of the external connection portion through the second window portion.

ADVANTAGEOUS EFFECTS

According to the present disclosure, it is possible to provide an in-vehicle-component circuit unit that can achieve a simplified connection structure between an external connection portion of the in-vehicle-component circuit unit and a connector provided in a casing of an in-vehicle component, as well as improved connection workability.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

First, aspects of the present disclosure will be listed and described.

An in-vehicle-component circuit unit according to the present disclosure is an in-vehicle-component circuit unit configured to be housed in a casing of an in-vehicle component, including: a circuit constituent member; an insulating case accommodating the circuit constituent member; a connection bus bar accommodated in the case and including an internal connection portion to be conductively connected to a circuit-side connection portion provided in the circuit constituent member, and an external connection portion to be conductively connected to a connector-side connection portion of a connector provided on the casing; a first window portion provided in the case and disposed facing the internal connection portion of the connection bus bar and a first bolt insertion hole provided in the internal connection portion; and a second window portion provided in the case and disposed facing the external connection portion of the connection bus bar and a second bolt insertion hole provided in the external connection portion, wherein the first bolt insertion hole and the second bolt insertion hole are each sized to include a tolerance absorbing gap extending in a tolerance absorbing direction, the connection bus bar is accommodated so as to be displaceable relative to the case in the tolerance absorbing direction, the first window portion is open with a size that enables a bolt fastening operation to be performed from an exterior of the case to the circuit-side connection portion of the internal connection portion through the first window portion, and the second window portion is open with a size that enables a bolt fastening operation to be performed from the exterior of the case to the connector-side connection portion of the external connection portion through the second window portion.

With the in-vehicle-component circuit unit according to the present aspect, the connection bus bar that conductively connects the circuit-side connection portion and the connector-side connection portion to each other is accommodated in the case so as to be displaceable in the tolerance absorbing direction. Furthermore, the internal connection portion and the external connection portion of the connection bus bar accommodated in the case can be bolt-fastened from the exterior to the circuit-side connection portion and the connector-side connection portion, respectively, via the first window portion and the second window portion provided in the case. Therefore, in a state in which the circuit unit is disposed in the casing of the in-vehicle component, and the connection bus bar is displaced in the tolerance absorbing direction to absorb a tolerance, the internal connection portion and the external connection portion of the connection bus bar can be aligned with the circuit-side connection portion and the connector-side connection portion, respectively, and bolt-fastened thereto from the exterior. This eliminates the need for relay components, such as a coated wire and a bus bar, that have been conventionally required to connect a connector provided on a casing to an external connection portion provided in a circuit unit housed in the casing, so that it is possible to achieve a simplified connection structure between an in-vehicle-component circuit unit and a connector provided in a casing of an in-vehicle component. Moreover, since the connection bus bar is accommodated in the case, it is also possible to advantageously provide protection against electric shocks using the case. Furthermore, the first window portion and the second window portion provided in the case need only be open with a size that enables a bolt fastening operation of the connection portions to be performed from the exterior. Accordingly, portions that may become current-carrying portions can be covered by the case to the greatest extent possible, thus also achieving improved connection workability.

Note that the tolerance absorbing direction may be set as required, and one direction or a plurality of directions may be set. The first/second window portion need only be open with a size that enables a bolt fastening operation of the connection portions to be performed from the exterior of the case. The size may be a size that allows passage of a bolt or a nut when the bolt or the nut is not contained in the case, or may be a size that prevents a bolt or a nut from being detached from the window portions and allows passage of a fastening tool when the bolt or the nut is contained in the case.

It is preferable that each of the first window portion and the second window portion is surrounded by a tubular portion protruding outward of the case. Since the first window portion and the second window portion are surrounded by the tubular portions protruding outward of the case, adjusting the protruding heights of the tubular portions can advantageously prevent a worker from coming into contact with the internal connection portion and the external connection portion, which may become current-carrying portions.

It is preferable that a bolt or a nut is accommodated in an interior of the tubular portion of each of the first window portion and the second window portion, a retaining projection protruding radially inward is provided on a protruding distal end side of the tubular portion, and the bolt or the nut is prevented from being detached from the tubular portion by abutting against the retaining projection. Using the internal spaces of the tubular portions of the first window portion and the second window portion, a bolt or a nut for bolt fastening the internal connection portion and the external connection portion of the connection bus bar to the circuit-side connection portion and the connector-side connection portion can be contained in the case in advance, so that it is possible to further improve the workability. Since the bolt or the nut is accommodated in each of the tubular portions of the first window portion and the second window portion, the sizes of the openings of the first window portion and the second window portion can be reduced to a size that does not allow passage of the bolt or the nut but allows passage of a fastening tool, so that it is possible to further enhance the protection against electric shocks. In particular, it is possible to further enhance the protection against electric shocks by insulating portions of the contained bolt or nut that are exposed from the window portions.

It is preferable that the bolt or the nut accommodated in each of the tubular portions includes an insulated portion, and the insulated portion of the bolt or the nut is configured to: protrude to an exterior from the tubular portion in a non-fastened state; and be accommodated in the tubular portion in a fastened state. Since the bolt or the nut accommodated in each of the tubular portions have an insulated portion, it is possible to prevent an electric shock through a fastening tool during a fastening operation. In particular, when the insulated portion protrudes to the exterior from the tubular portion in a non-fastened state of the bolt or the nut, the non-fastened state can be easily confirmed visually, and the fastening operation can also be performed easily. Moreover, since the protruding portion is the insulated portion, it is also possible to maintain the protection against electric shocks. Furthermore, since the insulated portion is accommodated in the tubular portion in a fastened state, the fastened state can be easily confirmed from the exterior. Furthermore, the height of protrusion of the tubular portion to the exterior of the case can also be minimized for a finished product for which fastening has been completed, so that it is also possible to reduce the size of the in-vehicle-component circuit unit.

It is preferable that the case includes a case body including a placement portion on which the connection bus bar is placed, and a cover part covering the placement portion and attached to the case body so as to be displaceable relative to the case body in the tolerance absorbing direction, and the cover part includes the first window portion and the second window portion, and is displaced together with the connection bus bar in the tolerance absorbing direction. The case is divided into the case body including the placement portion on which the connection bus bar is placed, and the cover part covering the placement portion and attached to the case body so as to be displaceable relative to the case body in the tolerance absorbing direction, and the cover part is displaced together with the connection bus bar. Accordingly, a structure that accommodates the connection bus bar so as to be displaceable relative to the case in the tolerance absorbing direction can be provided in a simple and reliable manner. Moreover, since the cover part, which constitutes a part of the case, is displaced together with the connection bus bar, the sizes of the openings of the first window portion and the second window portion can be smaller than when only the connection bus bar is displaced relative to the case. Accordingly, it is possible to provide safer protection against electric shocks.

It is preferable that the case body includes a fitting hole extending in the tolerance absorbing direction in an area surrounding the placement portion, and the cover part includes a fitting projection protruding from a peripheral edge portion of the cover part toward the case body so as to be fitted to the fitting hole, and the fitting projection has a smaller width dimension in the tolerance absorbing direction than the fitting hole. Since the width dimension, in the tolerance absorbing direction, of the fitting projection of the cover part to be fitted to the fitting hole provided in the case body is smaller than the width dimension of the fitting hole in the tolerance absorbing direction, the fitting projection is displaceable in the fitting hole in the tolerance absorbing direction. As a result, the cover part including the fitting projection is displaceable relative to the case body in the tolerance absorbing direction, so that the fitting projection and the fitting hole for attaching the cover part to the case body can be used to define the end of movement of the cover part (connection bus bar) to the case body in the tolerance absorbing direction.

It is preferable that the fitting projection includes a locking pawl provided at a protruding end portion of the fitting projection and protruding toward the placement portion side relative to the fitting hole, and the locking pawl inserted in the fitting hole is engaged with an edge portion of the fitting hole that is located on the placement portion side. Since the locking pawl protrudes toward the placement portion side relative to the fitting hole and is engaged with an edge portion of the fitting hole that is located on the placement portion side, it is difficult to insert a tool such as a driver into the fitting hole so as to bend the fitting projection in a direction in which the locking pawl and the case body are disengaged from each other, so that the engagement between the locking pawl and the case body is stably maintained. In addition, the engaging portion between the locking pawl and the case body cannot be viewed from the exterior, so that it is possible to more reliably prevent disengagement between the locking pawl and the case body. Consequently, the cover part can be held against the case body in a fixed state. As a result, it is possible to reduce the possibility that a worker may receive an electric shock by accidentally removing the cover part from the case during maintenance.

It is preferable that the internal connection portion and the external connection portion extend in directions intersecting each other, the first bolt insertion hole provided in the internal connection portion and the second bolt insertion hole provided in the external connection portion pass through in directions intersecting each other, and the tolerance absorbing direction of the first bolt insertion hole in the tolerance absorbing gap and the tolerance absorbing direction of the second bolt insertion hole in the tolerance absorbing gap are orthogonal to each other. Since the internal connection portion and the external connection portion extend in directions intersecting each other, the first bolt insertion hole and the second bolt insertion hole that are provided in the internal connection portion and the external connection portion, respectively, are provided intersecting each other. Therefore, the tolerance absorbing direction in the tolerance absorbing gap of the first bolt insertion hole, and the tolerance absorbing direction in the tolerance absorbing gap of the second bolt insertion hole can be set to directions orthogonal to each other, so that the connection bus bar can be displaced relative to the case in at least two directions that are orthogonal to each other. Accordingly, the circuit constituent member to be conductively connected to the internal connection portion, and the connector to be conductively connected to the external connection portion can be stably connected to each other using the connection bus bar. Here, for example, when the tolerance absorbing directions in the tolerance absorbing gap of the first bolt insertion hole are set to two directions that are orthogonal to each other (e.g., front-rear and left-right directions), and the tolerance absorbing direction in the tolerance absorbing gap of the second bolt insertion hole includes a direction (e.g., up-down direction) orthogonal to the two directions, the connection bus bar can be displaced relative to the case in the up-down, left-right, and front-rear directions, thus allowing the circuit constituent member and the connector to be more reliably connected to each other via the connection bus bar.

It is preferable that the cover part includes a rib protruding toward the placement portion, and the rib abuts against or faces the connection bus bar while the cover part is attached to the case body. The rib provided on the cover part and protruding toward the placement portion side abuts against, or faces with a slight gap, the connection bus bar while the cover part is attached to the case body. Thus, the rib suppresses lifting of the connection bus bar when the connection bus bar is displaced so as to be lifted from the placement portion of the case body. This prevents the connection bus bar from rattling in the case. In particular, for example, when the connection bus bar is connected to a heat generating component such as a relay via the circuit constituent member, the circuit constituent member may include a heat dissipation portion that comes into contact with the heat transfer surface provided on the case body. In such a case, it is possible to prevent lifting of not only the connection bus bar, but also the circuit constituent member including the heat dissipation portion, by providing the rib on the cover part to prevent lifting of the connection bus bar. Accordingly, it is possible to advantageously prevent the heat dissipation portion from being lifted from the heat transfer surface toward the cover part side. Thus, it is also possible to stably maintain heat dissipation from the heat generating component via the connection bus bar.

It is preferable that the connection bus bar includes a first end portion provided with the internal connection portion, and a second end portion provided with the external connection portion and protruding above the first end portion, and the internal connection portion includes the first bolt insertion hole having the tolerance absorbing gap in an extension direction of the first end portion, and the external connection portion includes the second bolt insertion hole having the tolerance absorbing gap in an extension direction of the second end portion. The second end portion provided with the external connection portion protrudes above the first end portion provided with the internal connection portion of the connection bus bar, and the first bolt insertion hole and the second bolt insertion hole have tolerance absorbing gaps in extension directions of the first end portion and the second end portion that are different from each other. This makes it possible to set the tolerance absorbing directions to a plurality of directions, thus further increasing the ease of operation of attaching the in-vehicle-component circuit unit to the in-vehicle component. In particular, since the second end portion protrudes above the first end portion, a space for accommodating a component such as a wire harness can also be provided between these end portions.

It is preferable that the connection bus bar is a stack of a plurality of thin plates. Since the connection bus bar is a stack of a plurality of thin plates, the connection bus bar can be flexibly deformed. This also makes it possible to absorb a tolerance by deforming the connection bus bar, for example, even when the connection bus bar has a short length dimension and thus would have a large deformation stiffness if the bus bar is formed by a single flat plate-shaped bus bar. Accordingly, it is possible to more reliably connect the circuit-side connection portion provided in the circuit constituent member and the connector-side connection portion provided in the connector to each other.

Details of Embodiments of the Present Disclosure

Specific examples of an in-vehicle-component circuit unit according to the present disclosure will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications which fall within the scope of the claims and the meaning and scope of equivalents thereof.

The following describes Embodiment 1 of the present disclosure with reference toFIGS.1to16. An in-vehicle-component circuit unit10is mounted, for example, in a vehicle (not shown) such as an electric automobile and a hybrid automobile, and enables supply and control of power from a power supply (not shown) such as a battery to a load (not shown) such as a motor. Note thatFIG.1and so forth show a state in which the in-vehicle-component circuit unit10is housed in a casing14of a battery pack12as an in-vehicle component, and is fastened thereto using first and second bolts138and140, which will be described later. The in-vehicle-component circuit unit10and the in-vehicle component (battery pack12(casing14)) are not shown entirely, but relevant parts thereof are selectively shown. While the in-vehicle-component circuit unit10may be disposed in any orientation, in the following description, the upper side refers to the upper side inFIG.8, the lower side refers to the lower side inFIG.8, the forward side refers to the right side inFIG.5, the rear side refers to the left side inFIG.5, the left side refers to the lower side inFIG.5, and the right side refers to the upper side inFIG.5. For a plurality of identical members, reference numerals may be assigned to some of the members, and reference numerals may be omitted for the other members.

The in-vehicle-component circuit unit10is configured to be housed in the casing14of the in-vehicle component (battery pack12), and includes a circuit constituent member16and an insulating case18accommodating the circuit constituent member16. The case18accommodates therein connection bus bars30(first connection bus bar30aand second connection bus bar30b) including internal connection portions22(first internal connection portion22aand second internal connection portion22b) configured to be conductively connected to circuit-side connection portions20(first circuit-side connection portion20aand second circuit-side connection portion20b) provided in the circuit constituent member16, and external connection portions28(first external connection portion28aand second external connection portion28b) configured to be conductively connected to connector-side connection portions26(first connector-side connection portion26aand second connector-side connection portion26b) of a connector24provided on the casing14.

Although the in-vehicle component in which the in-vehicle-component circuit unit10is to be housed is not limited, the in-vehicle component is the battery pack12in the present embodiment. As also shown inFIG.2, the casing14of the battery pack12includes a casing body32and a lid member34. The casing body32, for example, has a substantially box shape that is open upward, and includes a bottom wall36, and a peripheral wall portion38protruding upward from a peripheral edge portion of the bottom wall36. Note thatFIG.2and so forth selectively show relevant portions of the battery pack12(casing14), with only a rear wall portion40shown as the peripheral wall portion38. However, wall portions constituting the peripheral wall portion38may be provided on the front side and the left and right sides of the bottom wall36.

The rear wall portion40has a connector insertion hole42provided therein to enable the connector-side connection portions26(connector-side connection portions26aand26b) of the connector24to be inserted into the casing14. The connector24can be attached to the casing14by inserting the connector-side connection portions26(connector-side connection portions26aand26b) into the casing body32through the connector insertion hole42, and fastening the connector24to the casing body32using bolts44. After the in-vehicle-component circuit unit10has been placed in the casing body32and electrically connected to the connector24, the upper opening of the casing body32is covered with the lid member34, which has a substantially flat plate shape, and the lid member34is fixed. Thus, the in-vehicle-component circuit unit10is housed in the casing14.

Although the shape of the connector24is not limited, the connector24includes a pair of wires46and46in the present embodiment. Each of the wires46is a coated wire, and includes a core wire48and an insulating coating50externally fitted to the core wire48. At an end portion (front end portion) of each of the wires46, the insulating coating50is stripped off to expose the core wire48. The core wire48exposed as a result of the insulating coating50having been stripped off is electrically connected to a connector terminal54in a connector housing52made of an insulating synthetic resin or the like. That is, due to the provision of the connector terminals54at end portions of the wires46, the connector24includes a pair of connector terminals54and54, and the connector terminals54and54are arranged in the left-right direction.

Each of the connector terminals54has a fastening hole provided in a front end portion thereof. In the present embodiment, these fastening holes constitute the first and second connector-side connection portions26aand26b.In short, the connection bus bars30of the in-vehicle-component circuit unit10and the connector24are to be conductively connected to each other by passing later-described second bolts140and140through the external connection portions28(first and second external connection portions28aand28b) of the connection bus bars30of the in-vehicle-component circuit unit10, and fastening the second bolts140and140to the fastening holes (first and second connector-side connection portions26aand26b) of the connector terminals54and54of the connector24.

Note that the connector housing52is fixed to the casing body32via an attachment portion56having a predetermined thickness. That is, the attachment portion56has insertion holes through which the connector-side connection portions26aand26bof the connector24and the bolts44and44are passed. While the connector24is fixed to the casing body32using the bolts44, the connector-side connection portions26aand26bpass through the attachment portion56and are exposed into the casing body32through the connector insertion hole42of the rear wall portion40.

In the present embodiment, as also shown inFIGS.3and4, the circuit constituent member16includes a pair of relays (first relay58aand second relay58b), and conduction bus bars62(first to fourth conduction bus bars62ato62d) to be connected to a pair of connection portions60and60provided in each of the relays58aand58b.In the present embodiment, the first relay58aand the second relay58bare disposed so as to face opposite sides to each other, with the left first relay58adisposed facing rearward, and the right second relay58bdisposed facing forward.

A first conduction bus bar62ais connected to the left connection portion60of the first relay58a,and the first conduction bus bar62ais electrically connected to an external circuit (not shown) on the left side of the in-vehicle-component circuit unit10. A second conduction bus bar62bis connected to the right connection portion60of the first relay58a.An end portion, of the second conduction bus bar62b,on a side opposite to a side connected to the first relay58aprotrudes above the first relay58avia a later-described heat dissipation portion64(second heat dissipation portion64b) located below the second conduction bus bar62b,and constitutes the first circuit-side connection portion20a.In particular, the first circuit-side connection portion20ais constituted by a bolt insertion hole passing through the second conduction bus bar62bin a plate thickness direction (up-down direction) at the end portion on the side opposite to the side connected to the first relay58a.

Furthermore, a third conduction bus bar62cis connected to the left connection portion60of the second relay58b.An end portion, of the third conduction bus bar62c,on a side opposite to a side connected to the second relay58bprotrudes above the second relay58bvia a later-described heat dissipation portion64(third heat dissipation portion64c) located below the third conduction bus bar62c,and constitutes the second circuit-side connection portion20b.In particular, the second circuit-side connection portion20bis constituted by a bolt insertion hole passing through the third conduction bus bar62cin a plate thickness direction (up-down direction) at the end portion located on the side opposite to the side connected to the second relay58b.Furthermore, a fourth conduction bus bar62dis connected to the right connection portion60of the second relay58b,and the fourth conduction bus bar62dis electrically connected to the external circuit (not shown) on the right side of the in-vehicle-component circuit unit10.

The conduction bus bars62(first to fourth conduction bus bars62ato62d) are each made of a conductive metal plate material, and formed by bending the metal plate material into a predetermined shape by press working or the like. The first to fourth conduction bus bars62ato62deach have a lower portion extending in a horizontal direction (direction orthogonal to the up-down direction), and these lower portions extending in the horizontal direction constitute heat dissipation portions64(first to fourth heat dissipation portions64ato64d). As will be described later, the first and second connection bus bars30aand30bare connected to the second and third conduction bus bars62band62c.Therefore, the first and second connection bus bars30aand30bindirectly include the heat dissipation portions64(second and third heat dissipation portions64band64c) via the second and third conduction bus bars62band62c.

The case18includes a case body68including a placement portion66on which the connection bus bars30are placed, and a cover part70covering the placement portion66and attached to the case body68.

The case body68includes an upper case72and a lower case74that are assembled to each other in the up-down direction. The upper case72and the lower case74have box shapes that are open upward and downward, respectively, and are each made of a hard synthetic resin, for example. That is, the upper case72has an upper wall76having a substantially rectangular shape as a whole, and an upper peripheral wall78protruding downward from a peripheral edge portion of the upper wall76. A rear end wall portion79protruding upward is provided at a right portion at a rear end of the upper wall76. Note thatFIGS.3,4and so forth selectively show relevant portions of the in-vehicle-component circuit unit10, showing only the upper front wall80and the upper rear wall82as the upper peripheral wall78. However, wall portions constituting the upper peripheral wall78may be provided on left and right sides of the upper wall76.

As also shown inFIG.7, the upper wall76has at least one substantially rectangular through window84passing therethrough in the plate thickness direction (up-down direction). In the present embodiment, through windows84(first through window84aand second through window84b) are provided in two locations of the upper wall76. The first through window84aand the second through window84bare provided at positions respectively corresponding to the first circuit-side connection portion20aof the second conduction bus bar62band the second circuit-side connection portion20bof the third conduction bus bar62c.Specifically, the first through window84ais provided at a substantially central portion of the upper wall76, and the second through window84bis provided at a right rear portion of the upper wall76. Accordingly, while the circuit constituent member16is accommodated in the case body68, the first circuit-side connection portion20aand the second circuit-side connection portion20bare exposed to the exterior through the first through window84aand the second through window84b.

As will be described later, the connection bus bars30(first connection bus bar30aand second connection bus bar30b) are overlaid from above with the first circuit-side connection portion20aand the second circuit-side connection portion20bexposed through the first through window84aand the second through window84b.A region of the upper wall76in which the first connection bus bar30aand the second connection bus bar30bare placed and overlaid constitutes the placement portion66. In the present embodiment, the placement portion66is formed including a region of the upper wall76that extends from the first through window84ato the second through window84b,that is, including, for example, a region extending from a rear portion of the first through window84ato a left portion of the second through window84b.

At least one fitting hole86extending through the upper wall76in the plate thickness direction is provided in an area surrounding the placement portion66. The fitting hole86is configured to be fitted to a later-described fitting projection132provided on the cover part70. In the present embodiment, a plurality of fitting holes86are provided, including three fitting holes86in an area surrounding the first through window84a,and one fitting hole86in an area surrounding the second through window84b.The fitting holes86each have a substantially rectangular shape extending in the front-rear direction, which is one of tolerance absorbing directions described later, and have an opening width dimension b (seeFIG.7) in the front-rear direction that is larger than an opening width dimension a (seeFIG.7) in the left right direction.

The lower case74includes a lower wall88having a substantially rectangular shape as a whole, and a lower peripheral wall90protruding upward from a peripheral edge portion of the lower wall88. Note thatFIGS.3,4and so forth selectively show relevant portions of the in-vehicle-component circuit unit10, showing only a lower front wall92and a lower rear wall94as the lower peripheral wall90. However, wall portions constituting the lower peripheral wall90may be provided on left and right sides of the lower wall88.

As also shown inFIGS.3and4, at least one upwardly protruding bus bar fixing portion96having a substantially rectangular columnar shape is provided on the lower wall88. In the present embodiment, bus bar fixing portions96(first bus bar fixing portion96aand second bus bar fixing portion96b) are provided at two locations of the lower wall88. The first bus bar fixing portion96aand the second bus bar fixing portion96bare provided at positions respectively corresponding to the first circuit-side connection portion20aof the second conduction bus bar62band the second circuit-side connection portion20bof the third conduction bus bar62c.Specifically, the first bus bar fixing portion96ais provided at a substantially central portion of the lower wall88, and the second bus bar fixing portion96bis provided at a right rear portion of the lower wall88. A nut98is provided in an embedded state at an upper end portion of each of the first and second bus bar fixing portions96aand96b.

While the circuit constituent member16is accommodated in the case body68, the heat dissipation portions64(first to fourth heat dissipation portions64ato64d) of the conduction bus bars62(first to fourth conduction bus bars62ato62d) are overlaid with the lower wall88of the lower case74. Substantially sheet-shaped heat transfer sheets100each made of a material having relatively good heat transfer efficiency are provided between the heat dissipation portions64ato64dand the lower wall88, and the heat dissipation portions64ato64dcome into contact with the lower wall88via the corresponding heat transfer sheets100. As will be described later, the lower wall88of the case body68will be overlaid with the bottom wall36of the casing14of the battery pack12. At positions respectively corresponding to the heat transfer sheets100between the lower wall88and the bottom wall36, gap fillers102each made of a material having a relatively good heat transfer efficiency are provided, and the lower wall88comes into contact with the bottom wall36via the gap fillers102. That is, heat generated due to energization of the relays58aand58bis dissipated from the bottom wall36via the heat dissipation portions64ato64d,the heat transfer sheets100, the lower wall88, and the gap fillers102. Accordingly, in the present embodiment, the heat transfer surface104, which is provided on the case body68and comes into contact with the heat dissipation portions64ato64dto transfer the heat generated due to energization of the relays58aand58b,is constituted by the upper surface of the lower wall88.

The materials of the heat transfer sheets100and the gap fillers102are not limited as long as the materials are insulating. For example, the heat transfer sheets100and the gap fillers102may be made of a synthetic resin having higher thermal conductivity than the air. Specifically, it is possible to use a silicone resin or a non-silicone resin such as an acrylic resin or a ceramic resin. More specific examples include a heat dissipation sheet, a heat dissipation gap filler, a heat-conductive grease, and a heat-conductive silicone rubber that are made of a silicone resin. Note that the heat transfer member provided between each of the heat dissipation portions64ato64dand the lower wall88is not limited to a sheet-shaped heat transfer member, and any known heat transfer member may be used. Although the gap fillers102are shown to have a substantially rectangular block shape inFIGS.3and4, the shape of the gap fillers102is not limited, and any known gap filler (heat transfer member) may be used.

In particular, the heat transfer sheets100and the gap fillers102are elastically deformable in the thickness direction (up-down direction), and elastic deformation of the heat transfer sheets100and the gap fillers102in the up-down direction may also enable tolerances in the up-down direction between the in-vehicle-component circuit unit10and the casing14of the battery pack12to be absorbed during an operation of bolt fastening the external connection portions28aand28band the connector-side connection portions26aand26bto each other using the second bolts140.

The cover part70has a shape covering the placement portion66of the case body68and spanning the first through window84aof the upper case72and the second through window84b.That is, as also shown inFIGS.11and12, the cover part70includes a horizontal wall portion106extending in the left-right direction and extending in a substantially horizontal direction (direction orthogonal to the up-down direction). In addition, a vertical wall portion108protruding upward and extending in the up-down direction is provided at a right portion at a rear end of the horizontal wall portion106. Thus, the cover part70has a substantially L-shaped longitudinal cross section at the right portion.

The horizontal wall portion106of the cover part70is provided with first window portions110passing therethrough in the plate thickness direction (up-down direction) at positions corresponding to the through windows84and the circuit-side connection portions20exposed through the through windows84, while the cover part70is attached to the case body68. In the present embodiment, the horizontal wall portion106is provided with a left first window portion110aand a right first window portion110bat positions respectively corresponding to the first and second circuit-side connection portions20aand20b.Furthermore, the vertical wall portion108is provided with second window portions112passing therethrough in the plate thickness direction (front-rear direction) at positions corresponding to the connector-side connection portions26, while the in-vehicle-component circuit unit10is housed in the casing14of the battery pack12. In the present embodiment, the vertical wall portion108is provided with a left second window portion112aand a right second window portion112bat positions respectively corresponding to the first and second connector-side connection portions26aand26b.

As will be described later, the first and second circuit-side connection portions20aand20bare overlaid with and conductively connected to the internal connection portions22(first and second internal connection portions22aand22b) of the connection bus bars30aand30b.Accordingly, the left and right first window portions110aand110bare provided at positions corresponding to the first and second internal connection portions22aand22b.That is, in an assembled state of the in-vehicle-component circuit unit10, the left and right first window portions110aand110bare disposed facing, in the up-down direction, the internal connection portions22aand22band first bolt insertion holes152respectively provided in the internal connection portions22aand22b.The first and second connector-side connection portions26aand26bare overlaid with and conductively connected to the external connection portions28(first and second external connection portions28aand28b) of the connection bus bars30aand30b.Accordingly, the left and right second window portions112aand112bare provided at positions corresponding to the first and second external connection portions28aand28b.That is, in the assembled state of the in-vehicle-component circuit unit10, the left and right second window portions112aand112bare disposed facing, in the front-rear direction, the external connection portions28aand28band second bolt insertion holes156respectively provided in the external connection portions28aand28b.

In the present embodiment, the left and right first window portions110aand110band the left and right second window portions112aand112bhave the same shape, and each formed as a circular through hole having a predetermined inner diameter dimension ϕA (seeFIG.8). The inner diameter dimension ϕA of the left and right first window portions110aand110bmay be sized to allow passage of a tool for performing, from the exterior of at least the case18, an operation of bolt fastening the internal connection portions22aand22band the circuit-side connection portions20aand20bto each other using first bolts138, which will be described later. In the present embodiment, the inner diameter dimension ϕA of the left and right first window portions110aand110bis larger than a maximum outer diameter dimension ϕC (seeFIG.14) of head portions144of first bolts138including insulated portions146, which will be described later. Similarly, the inner diameter dimension ϕA of the left and right second window portions112aand112bmay have a size that allows passage of a tool for performing, from the exterior of at least the case18, an operation of bolt fastening the external connection portions28aand28band the connector-side connection portions26aand26bto each other using second bolts140, which will be described later. In the present embodiment, the inner diameter dimension ϕA of the left and right second window portions112aand112bis larger than a maximum outer diameter dimension ϕC of head portions144of second bolts140including insulated portions146, which will be described later.

First tubular portions114and114in the form of tubular portions protruding upward from peripheral edges of the left and right first window portions110aand110b,respectively, are provided on the horizontal wall portion106, and second tubular portions116and116in the form of tubular portions protruding forward from peripheral edges of the left and right second window portions112aand112b,respectively, are provided on the vertical wall portion108. That is, all of the first and second tubular portions114and116protrude outward of the cover part70and the case18formed by attaching the cover part70.

The first and second tubular portions114and116each have a predetermined protruding height dimension. Also, a retaining projection118protruding radially inward is provided on the protruding distal end side of each of the first and second tubular portions114and116. In the present embodiment, the retaining projection118is formed with a circular ring shape extending fully circumferentially around the protruding distal ends of the first and second tubular portions114and116. Thus, an outer opening portion120of each of the first and second tubular portions114and116has a predetermined inner diameter dimension, and the first and second tubular portions114and116have an inner diameter dimension (inner diameter dimension of the retaining projection118) ϕA′ (seeFIG.8) that is smaller than the inner diameter dimension ϕA of the first window portions110aand110b.

Furthermore, a lower protection wall portion122protruding downward is provided at a peripheral edge of the horizontal wall portion106, and a rear protection wall portion124protruding rearward is provided at a peripheral edge of the vertical wall portion108. The lower protection wall portion122and the rear protection wall portion124are formed continuously over substantially the entire perimeters of the horizontal wall portion106and the vertical wall portion108, and formed so as to be continuous and integrated with each other at the connection portion between the horizontal wall portion106and the vertical wall portion108. Furthermore, a partition wall portion126dividing a region surrounded by the lower protection wall portion122and the rear protection wall portion124into two regions is provided on the lower surface of the horizontal wall portion106and the rear surface of the vertical wall portion108. That is, the partition wall portion126has a substantially L-shape spanning the horizontal wall portion106and the vertical wall portion108. Also, of the two regions divided by the partition wall portion126, the left region constitutes a first accommodating region128ain which the first connection bus bar30ais accommodated, and the right region constitutes a second accommodating region128bin which the second connection bus bar30bis accommodated.

InFIG.12, the first and second connection bus bars30aand30baccommodated in the first and second accommodating region128aand128bare indicated by the dashed double-dotted lines. As also shown inFIG.12, the connection bus bars30aand30bface the wall portions122,124, and126, which constitute the accommodating regions128aand128b,with a slight gap in the front-rear direction and the left-right direction, and the connection bus bars30aand30bare slightly displaceable in the left-right direction in the accommodating regions128aand128b.Note that a later-described vertical portion150of each of the connection bus bars30aand30bis sandwiched between the vertical wall portion108(later-described ribs130) of the cover part70and the rear end wall portion79of the upper case72in the front-rear direction. Accordingly, displacement of the connection bus bars30aand30bin the front-rear direction in the accommodating regions128aand128bis substantially impossible. As will be described later, the cover part70is displaceable relative to the case body68(upper case72) in the front-rear direction, and therefore the connection bus bars30aand30bare displaceable together with the cover part70relative to the case body68(upper case72) in the front-rear direction.

Inside the region surrounded by the lower protection wall portion122and the rear protection wall portion124, ribs130protruding toward the placement portion66and the rear end wall portion79, respectively, are provided on the lower surface of the horizontal wall portion106and the rear surface of the vertical wall portion108. That is, the ribs130are provided in both the first accommodating region128aand the second accommodating region128bdivided by the partition wall portion126. In the present embodiment, a plurality of ribs130are provided, and each of the ribs130is formed as a protrusion extending in the front-rear direction or the left-right direction. The plurality of ribs130constitute a grid pattern as a whole, and are integrally formed.

When the cover part70is attached to the upper case72while the connection bus bars30aand30bare accommodated in the first and second accommodating region128aand128b,the ribs130are slightly compressed between the connection bus bars30aand30band the horizontal wall portion106and the vertical wall portion108, or the ribs130and the connection bus bars30aand30babut against each other with zero touch, or the ribs130and the connection bus bars30aand30bface each other with a slight separation therebetween. That is, when the ribs130are compressed, the elastic restoring force of the ribs130causes the connection bus bars30aand30bto be pressed against the upper wall76(placement portion66) and the rear end wall portion79of the upper case72from above and the front. During assembly of the in-vehicle-component circuit unit10, the ribs130suppress the connection bus bars30aand30bfrom being lifted from the placement portion66, thus limiting upward displacement of the second and third conduction bus bars62band62cthat come into contact with the connection bus bars30aand30bfrom below. This allows the second and third heat dissipation portions64band64cof the second and third conduction bus bars62band62cto more reliably come into contact with the heat transfer surface104of the lower wall88of the lower case74via the heat transfer sheets100.

Furthermore, the lower protection wall portion122is provided with fitting projections132that protrude toward the case body68therebelow and are to be fitted to the fitting holes86. The fitting projections132are provided at positions corresponding to the fitting holes86of the upper case72, and four fitting projections132are provided in the present embodiment. Specifically, three fitting projections132are provided on the lower protection wall portion122covering the first accommodating region128a,and one fitting projection132is provided on the lower protection wall portion122covering the second accommodating region128b.The fitting projections132have a width dimension in the front-rear direction that is smaller than a width dimension b of the fitting holes86in the front-rear direction, and the fitting projections132are displaceable in the front-rear direction in the fitting holes86. In short, the cover part70is displaceable in the front-rear direction relative to the case body68(upper case72) to which the cover part70is attached, by the amount corresponding to the amount by which the fitting projections132are displaceable in the fitting holes86.

A locking pawl134is provided at a protruding end portion (lower end portion) of each of the fitting projections132. The locking pawls134protrude inward, or in other words, toward the placement portion66side relative to the fitting holes86into which the fitting projections132are inserted in the case body68(upper case72) to which the cover part70is attached.

Note that the method for forming the cover part70is not limited. In the present embodiment, the cover part70is formed by injection molding, and punch-out holes136for forming the locking pawl134by injection molding are formed in the horizontal wall portion106at positions facing the locking pawls134. In particular, in the present embodiment, the punch-out holes136each have a substantially rectangular shape, and, for, example, are formed to have a size that does not allow a tool or the like, such as a driver, used for bolt fastening to be inserted into the punch-out holes136. Specifically, the punch-out holes136have a width dimension c (seeFIG.5) in the left-right direction that is smaller than a width dimension d (seeFIG.5) in the front-rear direction.

In the present embodiment, first bolts138and138and second bolts140and140are accommodated in the first tubular portions114and114and the second tubular portions116and116, respectively, of the cover part70having the above-described shape. The first and second bolts138and140have substantially the same shape, and each have a shaft portion142having a predetermined maximum outer diameter dimension ϕB (seeFIG.14), and a head portion144provided with an insulated portion146. The head portions144including the insulated portions146have a maximum outer diameter dimension ϕC that is larger than the inner diameter dimension ϕA′ of the outer opening portions120of the first and second tubular portions114and116. As a result of peripheral edges of the head portions144including the insulated portions146abut against the retaining projections118of the first and second tubular portions114and116, the first and second bolts138and140are prevented from being detached from the first and second tubular portions114and116. Note that the method for providing the insulated portions146on the head portions144of the first and second bolts138and140is not limited. For example, a cap made of synthetic resin may be fixed to the head portion144of each of the first and second bolts138and140through fastening or the like, or such a cap and bolt may be integrally formed.

Connection Bus Bar30

In the present embodiment, two bus bars are adopted as the connection bus bars30to be accommodated in the case18, with the left bus bar constituting the first connection bus bar30a,and the right bus bar constituting the second connection bus bar30b.As also shown inFIG.14, each of the first and second connection bus bars30aand30bincludes, at a lower end portion thereof, a horizontal portion148extending in the horizontal direction, and also includes, at a rear end portion thereof in the horizontal direction, a vertical portion150protruding upward and extending in the up-down direction. That is, each of the first and second connection bus bars30aand30bis substantially L-shaped as a whole.

Also, the first internal connection portion22ato be conductively connected to the first circuit-side connection portion20ais provided at a front end portion151a(end portion of the horizontal portion148on a side opposite to a side connected to the vertical portion150) serving as a first end portion of the first connection bus bar30a.A first external connection portion28aconnected to the first connector-side connection portion26ais provided at an upper end portion151b(end portion of the vertical portion150on a side opposite to a side connected to the horizontal portion148) serving as a second end portion of the first connection bus bar30a.Similarly, the second internal connection portion22bto be conductively connected to the second circuit-side connection portion20bis provided at a front end portion151aserving as a first end portion of the second connection bus bar30b.The second external connection portion28bconnected to the second connector-side connection portion26bis provided at an upper end portion151bserving as a second end portion of the second connection bus bar30b.That is, in each of the connection bus bars30aand30b,the front end portion151aserving as the first end portion extends in the front-rear direction (direction extending from the rear side toward the front side), and the upper end portion151bserving as the second end portion extends in the up-down direction (direction from the lower side toward the upper side).

In the first and second connection bus bars30aand30b,the internal connection portions22aand22beach have a first bolt insertion hole152passing therethrough in the plate thickness direction (up-down direction). In the present embodiment, the first bolt insertion hole152has a substantially perfect circular shape and has a predetermined inner diameter dimension ϕD (seeFIG.14). The inner diameter dimension ϕD of the first bolt insertion hole152is larger than the maximum outer diameter dimension ϕB of the shaft portion142of the first bolt138, and the space between the first bolt insertion hole152and the shaft portion142of the first bolt138serves as a tolerance absorbing gap154in which a tolerance can be absorbed when the first bolt138is passed through the first bolt insertion hole152. That is, the first bolt insertion hole152is sized to include the tolerance absorbing gap154. Since the first bolt insertion hole152has a substantially perfect circular shape, the tolerance absorbing gap154has a circular ring shape extending fully circumferentially, and the horizontal direction including the front-rear direction and the left-right direction is a tolerance absorbing direction in which a tolerance can be absorbed in the first bolt insertion hole152.

In the first and second connection bus bars30aand30b,the external connection portions28aand28beach have a second bolt insertion hole156extending therethrough in the plate thickness direction (front-rear direction). In the present embodiment, the second bolt insertion hole156has a substantially perfect circular shape and has a predetermined inner diameter dimension ϕE (seeFIG.14). The inner diameter dimension ϕE of the second bolt insertion hole156is larger than the maximum outer diameter dimension ϕB of the shaft portion142of the second bolt140, and the space between the second bolt insertion hole156and the shaft portion142of the second bolt140serves as a tolerance absorbing gap158in which a tolerance can be absorbed when the second bolt140is passed through the second bolt insertion hole156. That is, the second bolt insertion hole156is sized to include the tolerance absorbing gap158. Since the second bolt insertion hole156has a substantially perfect circular shape, the tolerance absorbing gap158has a circular ring shape extending fully circumferentially, and a direction orthogonal to the front-rear direction, including the up-down direction and the left-right direction, is a tolerance absorbing direction in which a tolerance can be absorbed in the second bolt insertion hole156.

Assembling Step of In-Vehicle-Component Circuit Unit10

Next, a specific example of an assembling step of the in-vehicle-component circuit unit10will be described. Note that the assembling step of the in-vehicle-component circuit unit10is not limited to the following description.

First, bolts160are fastened to the connection portions60of the first and second relays58aand58bto fix the first to fourth conduction bus bars62ato62d.The first and second relays58aand58bto which the first to fourth conduction bus bars62ato62dhave been fixed are fixed to the upper wall76of the upper case72using bolts. Thereafter, the upper case72and the lower case74are attached to each other, and then fixed to each other using a locking mechanism or the like (not shown). This causes first to fourth heat dissipation portions64ato64dof the first to fourth conduction bus bars62ato62dto come into contact with the heat transfer surface104of the lower wall88via the heat transfer sheets100. Note that the heat transfer sheets100may be secured in advance to the lower surfaces of the first to fourth heat dissipation portions64ato64d,or be secured to the upper surface (heat transfer surface104) of the lower wall88. This results in completion of the case body68with the circuit constituent member16accommodated therein.

In the completed state of the case body68, the first and second bus bar fixing portions96aand96bof the lower case74abut from below against the first and second circuit-side connection portions20aand20bof the second and third conduction bus bars62band62c.In addition, the first and second circuit-side connection portions20aand20bare exposed to the exterior through the first and second through windows84aand84bof the upper case72.

Thereafter, the first and second connection bus bars30aand30bare placed on the placement portion66of the upper case72. Thus, the first and second internal connection portions22aand22bof the first and second connection bus bars30aand30bare overlaid with the first and second circuit-side connection portions20aand20bthat are exposed to the exterior. As a result, the bolt insertion holes constituting the first and second circuit-side connection portions20aand20band the first bolt insertion holes152provided in the first and second internal connection portions22aand22bare in communication with each other. Then, the first and second bolts138and140are inserted into the first and second bolt insertion holes152and156, respectively, of the first and second connection bus bars30aand30b.Note that, at this time, the first bolts138are not fastened to the nuts98located below the first and second circuit-side connection portions20aand20b.

Subsequently, with the first and second bolts138and140inserted into the first and second bolt insertion holes152and156, the cover part70is attached to the upper case72. Specifically, the fitting projections132of the cover part70are inserted into the fitting holes86of the upper case72, and the locking pawls134are locked to edges of the fitting holes86of the upper wall76of the upper case72that are located on the placement portion66side, as shown inFIG.10. Thus, the cover part70is attached to the case body68while accommodating the first and second connection bus bars30aand30bin the first and second accommodating region128aand128bof the cover part70, and accommodating the first and second bolts138and140in the first and second tubular portions114and116. This results in completion of the in-vehicle-component circuit unit10, to which the present disclosure is directed. Note that the external circuit (not shown) will be electrically connected to the first and fourth conduction bus bars62aand62dof the in-vehicle-component circuit unit10at an appropriate timing.

In the assembled state of the in-vehicle-component circuit unit10(state in which the in-vehicle-component circuit unit10is not housed in the casing14of the in-vehicle component (battery pack12)), the first and second bolts138and140are not fastened anywhere, and are disposed relatively freely (in a floating state) in the first and second tubular portions114and116. In this state, as shown inFIG.15, lower end portions of the first bolts138are in contact with the nuts98, and the insulated portions146provided on the head portions144of the first bolts138protrude outward from the outer opening portions120of the first tubular portions114. In a later-described fastened state of the first bolts138, the insulated portions146provided on the head portions144of the first bolts138are accommodated in the first tubular portions114. In this state, the second bolts140are relatively free in the second tubular portions116. Accordingly, the insulated portions146provided on the head portions144of the second bolts140may protrude outward from the outer opening portions120of the second tubular portions116, or may be accommodated in the second tubular portions116.

Next, a specific example of a step of housing the in-vehicle-component circuit unit10in the casing14of the in-vehicle component (battery pack12) will be described. Note that the step of housing the in-vehicle-component circuit unit10in the casing14of the in-vehicle component (battery pack12) is not limited to the following description.

First, the in-vehicle-component circuit unit10is placed in the casing body32with the connector24attached to the rear wall portion40. Thus, the lower surface of the case body68is in contact with the bottom wall36of the casing14via the gap fillers102. In addition, the second bolts140inserted into the second bolt insertion holes156are aligned with the connector-side connection portions26aand26bof the connector24. In this state, as shown inFIG.16, the second bolts140are not fastened to the connector-side connection portions26aand26b.Also, the distal ends (rear ends) of the second bolts140are in contact with the openings of the connector-side connection portions26aand26b,and the insulated portions146provided on the head portions144of the second bolts140protrude outward from the outer opening portions120of the second tubular portions116. In a later-described fastened state of the second bolts140, the insulated portions146provided on the head portions144of the second bolts140are accommodated in the second tubular portions116.

From this state, a tool or the like is inserted through the outer opening portion120of each of the second tubular portions116, and the second bolts140are fastened to the connector-side connection portions26aand26busing the tool. Thus, the connector24and the connection bus bars30aand30bare electrically connected to each other via the second bolts140. Thereafter, a tool or the like is inserted through the outer opening portion120of each of the first tubular portions114, and the first bolts138are fastened to the nuts98through the first bolt insertion holes152and the circuit-side connection portions20aand20busing the tool. Thus, the second and third conduction bus bars62band62celectrically connected to the relays58aand58bare electrically connected to the connection bus bars30aand30bvia the first bolts138. As a result, the external circuit is electrically connected to the connector24via the circuit constituent member16(first to fourth conduction bus bars62ato62d,first and second relays58aand58b), and the first and second connection bus bars30aand30b.After fastening the first and second bolts138and140, the lid member34is fixed against the upper opening of the casing body32, thus completing housing of the in-vehicle-component circuit unit10into the casing14of the in-vehicle component (battery pack12).

Note that the in-vehicle-component circuit unit10can be removed from the casing14of the battery pack12by reversing the order of the above-described steps. That is, after the fastening between the first bolts138and the nuts98has been released, the fastening between the second bolts140and the connector-side connection portions26aand26bis released. Thus, the in-vehicle-component circuit unit10can be removed from the casing14of the battery pack12. Note that the connection between the external circuit (not shown) and the first and fourth conduction bus bars62aand62dis cancelled at an appropriate timing.

With the in-vehicle-component circuit unit10housed in the casing14of the in-vehicle component (battery pack12) in this manner, the internal connection portions22aand22bof the connection bus bars30aand30bprovided in the case18are fastened to the circuit-side connection portions20aand20busing the first bolts138. Here, the connection bus bars30aand30bare displaceable together with the cover part70relative to the case body68in the front-rear direction (seeFIG.5), while being accommodated in the accommodating regions128aand128bof the cover part70, and the inner diameter dimension ϕD of the first bolt insertion holes152in the front-rear direction is also larger than the maximum outer diameter dimension ϕB of the shaft portions142of the first bolts138. Thus, when tolerances cause the positions of the first bolt insertions hole152and the positions of the circuit-side connection portions20aand20bto be displaced from each other in the front-rear direction during fastening of the first bolts138, the tolerances can be absorbed, thus allowing the first bolts138to be fastened more reliably.

Similarly, the connection bus bars30aand30bare displaceable in the left-right direction (seeFIG.5) in the accommodating regions128aand128bof the cover part70, and the inner diameter dimension ϕD, in the left right direction, of the first bolt insertion holes152through which the first bolts138are passed through the internal connection portions22aand22bis also larger than the maximum outer diameter dimension ϕB of the shaft portions142of the first bolts138. Thus, when tolerances cause the positions of the first bolt insertion holes152and the positions of the circuit-side connection portions20aand20bto be displaced from each other in the left-right direction during fastening of the first bolts138, the tolerances can be absorbed, thus allowing the first bolts138to be fastened more reliably.

Furthermore, the external connection portions28aand28bof the connection bus bars30aand30bprovided in the case18are fastened to the connector-side connection portions26aand26busing the second bolts140. Here, the inner diameter dimension ϕE of the second bolt insertion holes156is larger than the maximum outer diameter dimension ϕB of the shaft portions142of the second bolts140in the up-down direction. Thus, when tolerances cause the positions of the second bolt insertion holes156and the positions of the connector-side connection portions26aand26bto be displaced from each other in the up-down direction, the tolerances can be absorbed, for example, by adjusting the elastic deformation amount (compression amount) in the heat transfer sheets100and the gap fillers102, thus allowing the second bolts140to be fastened more reliably.

Furthermore, the inner diameter dimension ϕE, in the left right direction, of the second bolt insertions hole156through which the second bolts140are passed through the external connection portions28aand28bof the connection bus bars30aand30bis also larger than the maximum outer diameter dimension ϕB of the shaft portions142of the second bolts140. Thus, even when tolerances cause the positions between the second bolt insertion holes156and the connector-side connection portions26aand26bto be displaced in the left-right direction during fastening of the second bolts140, the tolerance can be absorbed, thus allowing the second bolts140to be fastened more reliably.

The connection bus bars30aand30bare provided in the case18, and portions of the connection bus bars30aand30bother than the first window portions110aand110band the second window portions112aand112bare covered by the case18(cover part70). This can reduce the possibility that a worker may receive an electric shock by accidentally coming into contact with a current-carrying portion during a bolt fastening operation or the like.

In particular, although the process of the bolt fastening operation is not limited, in the present embodiment, first, the external connection portions28aand28band the connector-side connection portions26aand26bare fastened to each other using the second bolts140, and thereafter the internal connection portions22aand22band the circuit-side connection portions20aand20bare fastened to each other using the first bolts138. Thus, during fastening of the second bolts140, the fastening portions on the first bolt138side to which power is supplied are in a non-fastened state, and therefore the fastening portions on the second bolt140side will not be current-carrying portions, thus enabling a safer bolt fastening operation.

The left and right first window portions110aand110band the left and right second window portions112aand112bare surrounded by the first and second tubular portions114and116each protruding outward of the case18. This can further reduce the possibility of causing an electric shock due to contact with the bolt-fastened portions, which may become current-carrying portions, through the first window portions110aand110band the second window portions112aand112bwhen fastening the first and second bolts138and140.

The first and second bolts138and140are accommodated inside the left and right first window portions110aand110band the left and right second window portions112aand112b,and the first and second bolts138and140are prevented from being detached from the first and second tubular portions114and116by the retaining projections118. This obviates the need to separately provide and fasten the first bolts and the second bolts, thus enhancing the bolt fastening workability. In particular, the provision of the retaining projections118can reduce the opening dimension of the outer opening portions120of the first and second tubular portions114and116, and it is thus possible to further reduce the possibility of causing an electric shock during bolt fastening.

Since the insulated portions146are provided on the head portions144, the first and second bolts138and140can reduce the possibility of giving an electric shock to a worker through a tool or the like during bolt fastening. In particular, the insulated portions146of the first and second bolts138and140protrude outward from the outer opening portions120when the bolts are not fastened, and are accommodated inside the outer opening portions120when the bolts are fastened. Accordingly, whether the first and second bolts138and140are in the fastened state or the non-fastened state can be visually determined from the exterior. In addition, only the insulated portions146of the first and second bolts138and140protrude outward when the bolts are not fastened. Accordingly, it is possible to reduce the possibility of causing an electric shock due to accidental contact.

The case18includes the case body68in which the connection bus bars30aand30bare placed, and the cover part70covering the connection bus bars30aand30band attached to the case body68. Also, the cover part70and the connection bus bars30aand30bare displaceable together relative to the case body68in the front-rear direction. Thus, the connection bus bars30aand30bwill not be exposed from the cover part70(case18), for example, when displaced in the front-rear direction, so that it is possible to further reduce the possibility that a worker may receive an electric shock by accidentally coming into contact with the connection bus bars30aand30b.Also, the cover part70is provided with the first window portions110aand110band the second window portions112aand112b,and the cover part70and the connection bus bars30aand30bare displaced together. Accordingly, the first window portions and the second window portions need not be formed large to accommodate displacement of the connection bus bars, and the opening dimensions of the first window portions110aand110band the second window portions112aand112bcan be set small, so that it is possible to further reduce the possibility of causing an electric shock.

The case body68includes the fitting holes86extending in the front-rear direction, the cover part70includes the fitting projections132configured to be fitted to the fitting holes86, and the fitting projections132are displaceable in the front-rear direction in the fitting hole86. Accordingly, it is possible to displace the cover part70relative to the case body68in the front-rear direction, while maintaining the assembled state of the case body68and the cover part70.

In particular, the fitting projections132have the locking pawls134, and the locking pawls134protrude inward toward the placement portion66side relative to the fitting holes86. The locking pawls134are configured to be engaged with edge portions of the fitting holes86of the upper case72that are located on the placement portion66side when the cover part70has been attached to the case body68. Thus, the engaging portions between the locking pawls134and the case body68(fitting holes86) cannot be viewed from the exterior. Even if a tool such as a driver is inserted into a fitting hole86, it will be difficult to bend the corresponding fitting projection132in a direction in which the locking pawl134and the fitting hole86are disengaged from each other. Accordingly, the mounted state of the case body68and the cover part70can be stably maintained, thus preventing, for example, an electric shock caused by accidental contact with the connection bus bars30aand30b.

The cover part70includes the ribs130on the surface thereof with which the connection bus bars30aand30bare overlaid, and the ribs130restrict upward displacement of the connection bus bars30aand30b,and hence upward displacement of the circuit constituent member16including the second and third conduction bus bars62band62c.This allows the heat dissipation portions64ato64dto more reliably come into contact with the heat transfer surface104of the lower wall88of the lower case74via the heat transfer sheets100, thus enhancing the heat dissipation efficiency through the casing14of the battery pack12. In particular, in the present embodiment, heat generated in the connection portions (portions to which the second bolts140are fastened) between the connector24and the in-vehicle-component circuit unit10can be dissipated through the casing14of the battery pack12, for example, via the connection bus bars30aand30band the second and third conduction bus bars62band62c(second and third heat dissipation portions64band64c).

The connection bus bars30aand30binclude the front end portions151aserving as the first end portions extending in the front-rear direction, and the upper end portions151bserving as the second end portions extending in the up-down direction. The first bolt insertion holes152are provided in the front end portions151a,and the second bolt insertion holes156are provided in the upper end portions151b.Also, the inner diameter dimension ϕD of the first bolt insertion holes152is larger than the outer diameter dimension ϕB of the shaft portions142of the first bolts138in the horizontal direction including the front-rear direction and the left-right direction, and the first bolt insertion holes152each includes a tolerance absorbing gap154. The inner diameter dimension ϕE of the second bolt insertion holes156is larger than the outer diameter dimension ϕB of the shaft portions142of the second bolts140in a direction orthogonal to the front-rear direction, including the up-down direction and the left-right direction, and the second bolt insertion holes156each include a tolerance absorbing gap158. Accordingly, the tolerance absorbing direction in the first bolt insertion holes152and the tolerance absorbing direction in the second bolt insertion holes156can be different from each other, so that it is possible to absorb tolerances in a plurality of directions.

Other Embodiments

The technique described in the present specification is not limited to the embodiments described and illustrated above. For example, the following embodiments also fall within the technical scope of the technique described in the present specification.

In the above embodiment, each of the connection bus bars30aand30bis formed by bending a single metal flat plate. However, as shown inFIG.17, first and second connection bus bars170aand170bmay each be formed as a stack of a plurality of thin plates172. This allows the connection bus bars170aand170bto be flexibly deformed, for example, even in the case where each of the connection bus bars has a short length and thus would have a relatively large deformation stiffness if the bus bar is formed by a single flat plate-shaped bus bar. As a result, it is possible to more efficiently absorb tolerances, thus stably connecting the circuit-side connection portions and the connector-side connection portions to the connection bus bars170aand170b.

In the above embodiment, the heat transfer sheets100and the gap fillers102are elastically deformable in the up-down direction to enable the in-vehicle-component circuit unit10to be displaced relative to the casing14of the battery pack12in the up-down direction, thus absorbing tolerances in the up-down direction. However, the present disclosure is not limited to this configuration. For example, a backlash in the up-down direction may be provided in each of the fitting portions (locking portions between the locking pawls and the upper wall of the upper case) between the fitting projections and the corresponding fitting holes, and the cover part and the connection bus bars may be fixed to each other, thus enabling the connection bus bars to be displaced together with the cover part relative to the case in the up-down direction to absorb tolerances in the up-down direction. The fitting projections may be displaceable in the fitting holes in the left-right direction to enable the connection bus bars to be displaced together with the cover part relative to the case in the left-right direction.

In the above embodiment, the left and right first window portions110aand110band the left and right second window portions112aand112bare provided in the cover part70. However, the cover part is not essential. That is, the connection bus bars may be displaceably accommodated in a case including an upper case and a lower case, and the first window portions and the second window portions may be formed in the upper wall of the upper case.

In the above embodiment, the insulated portion146is provided on each of the head portions144of the first and second bolts138and140. However, there is no limitation on the shape of the insulated portion. For example, a hexagonal hole portion may be provided in a central protruding portion of each of the insulated portions, and a tool may be inserted into the hole portion to perform bolt fastening. Thus, the opening dimension of the outer opening portions of the first and second tubular portions can be further reduced.

The first and second bolts are not limited to a configuration in which these bolts are accommodated in the first and second tubular portions, and may be configured to be fastened, as components separate from the in-vehicle-component circuit unit according to the present disclosure, to the circuit-side connection portions and the connector-side connection portions. That is, the first tubular portions and the second tubular portions are not essential for the in-vehicle-component circuit unit according to the present disclosure.

In the above embodiment, the nuts98and the connector-side connection portions26aand26bare disposed in a reception waiting state so as to be fastened to the first and second bolts138and140accommodated in the first tubular portions114and the second tubular portions116. However, for example, the first and second bolts may be disposed in a protruding state, and the nuts may be fastened thereto. The nuts may be accommodated in the first and second tubular portions as described above, or may be provided as components separate from the in-vehicle-component circuit unit according to the present disclosure.

In the above embodiment, the retaining projections118each have an annular shape extending continuously and fully circumferentially, but may be provided partially circumferentially.

In the above embodiment, two connection bus bars30aand30bare provided. However, one, or three or more connection bus bars may be provided. The number and the like of the relays and the conduction bus bars may be changed according to the number of the connection bus bars, and the type, shape, number, and the like of the members constituting the circuit constituent member are not limited.

In the above embodiment, the tolerance absorbing directions are set to the front-rear direction and the left-right direction, as well as the up-down direction. However, the tolerance absorbing directions are not limited thereto. When one tolerance absorbing direction is required, the connection bus bars may be displaceable only in one direction, which may be an oblique direction.

In the above embodiment, the first and second bolt insertion holes152and156each have a perfect circular shape, but may each have, for example, the shape of an elongated hole extending in the tolerance absorbing direction.

In the above embodiment, the ribs130that are provided on the inner surface of the cover part70suppress the first and second connection bus bars30aand30bfrom being lifted, thus also suppressing lifting of the second and third conduction bus bars62band62cconnected to the first and second connection bus bars30aand30b.However, the present disclosure is not limited to this configuration. For example, alternatively or in addition to the ribs on the cover part, ribs may be provided on the inner surface of the upper case, and the ribs on the inner surface of the upper case may suppress lifting of the conduction bus bars. As a result, the state of contact between the heat dissipation portions of the conduction bus bars and the heat transfer surface of the case body can be maintained, thus achieving a favorable heat dissipation effect.

In the above embodiment, the insulated portions146provided on the head portions144of the first and second bolts138and140protrude to the exterior from the first and second tubular portions114and116when the first and second bolts138and140are in a non-fastened state. However, the present disclosure is not limited to this configuration. That is, for example, the protruding height dimensions of the first and second tubular portions from the horizontal wall portion and the vertical wall portion of the cover part may be larger than the entire length of the first and second bolts (including the insulated portions), thus allowing the first and second bolts including the insulated portions provided on the head portions to be entirely accommodated in the first and second tubular portions even when the first and second bolts are in the non-fastened state as shown inFIGS.15and16. In that case, the insulated portions need not be provided on the head portions of the first and second bolts. Even when the first and second bolts are in the non-fastened state, accommodating the first and second bolts in the first and second tubular portions makes it possible to prevent a worker from receiving an electric shock by accidentally coming into contact with first and second bolts.