Patent Publication Number: US-2023156935-A1

Title: In-vehicle electrical component circuit unit

Description:
TECHNICAL FIELD 
     The present disclosure relates to an in-vehicle electrical component circuit unit that is housed in a casing of an in-vehicle electrical component. 
     BACKGROUND ART 
     Patent Document 1 discloses a structure in which a circuit unit such as a junction box or the like and a battery module, a battery control system, or the like are housed in a casing of a battery pack that is an in-vehicle electrical component for installation in a vehicle. Here, to enable connection between the circuit unit housed in the casing of the battery pack and an external device, a structure is employed where a connector to which an external partner connector is to be connected is provided on a peripheral wall of the casing, and a coated electrical wire or a bus bar is used to electrically connect the connector and the circuit unit to each other. 
     CITATION LIST 
     Patent Documents 
     Patent Document 1: JP 2012-243449A 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the structure disclosed in Patent Document 1, the connector is provided on the casing, which gives rise to the issue of the structure of the casing of the in-vehicle electrical component being complex. There is also the latent issue of shifting in the connection position between the connector provided on the casing and the circuit unit housed in the casing being likely to increase due to incremental increases in tolerance including surrounding components. Thus, the coated electrical wire needs to have a certain length in order to absorb the tolerance. 
     Therefore, disclosed herein is an in-vehicle electrical component circuit unit with a novel structure that enables simplifying the structure of a casing for an in-vehicle electrical component and reducing positional shifting caused by tolerance of the connection position between a connector and a circuit unit. 
     Solution to Problem 
     An in-vehicle electrical component circuit unit according to the present disclosure is an in-vehicle electrical component circuit unit including: an electrically insulative holding body configured to hold a circuit member; a plate wall portion configured to cover a casing through hole provided in a casing of an in-vehicle electrical component; a connector including a connection member that protrudes toward two sides in a plate thickness direction of the plate wall portion while held by the plate wall portion; and an annular sealing member that is provided on a first surface, which is a surface of the plate wall portion that is to be attached to the casing, and is configured to come into contact with a peripheral edge of the casing through hole, wherein a portion of the connection member that protrudes on a first surface side corresponding to the first surface of the plate wall portion includes a circuit-side connection portion, the circuit-side connection portion is detachably connectable to the circuit member, and the circuit-side connection portion of the connection member is inserted into the casing through hole from outside the casing and connected to the circuit member, and the sealing member of the wall plate portion comes into contact with the peripheral edge of the casing through hole from outside of the casing. 
     Advantageous Effects of Invention 
     With the present disclosure, it is possible to provide an in-vehicle electrical component circuit unit that can simplify the casing of the in-vehicle electrical component and reduce positional shift caused by tolerance of the connection position between a connector and a circuit unit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view showing an in-vehicle electrical component circuit unit according to Embodiment 1. 
         FIG.  2    is an exploded perspective view showing the in-vehicle electrical component circuit unit shown in  FIG.  1   . 
         FIG.  3    is a perspective view of an in-vehicle electrical component including the in-vehicle electrical component circuit unit shown in  FIG.  1   . 
         FIG.  4    is an exploded perspective view of the in-vehicle electrical component shown in  FIG.  3   . 
         FIG.  5    is an exploded perspective view of the in-vehicle electrical component shown in  FIG.  3    as seen from another direction. 
         FIG.  6    is a transverse cross-sectional view of the in-vehicle electrical component in which main portions of a cross section taken along line VI-VI in  FIG.  3    are enlarged. 
         FIG.  7    is a vertical cross-sectional view of a connector included in the in-vehicle electrical component circuit unit shown in  FIG.  1   , and corresponds to a cross section taken along line VII-VII in  FIG.  1   . 
         FIG.  8    is a plan view of a connector included in an in-vehicle electrical component circuit unit according to another embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Description of Embodiments of Present Disclosure 
     First, embodiments of the present disclosure will be listed and described below. 
     An in-vehicle electrical component circuit unit of the present disclosure is 
     an in-vehicle electrical component circuit unit according to the present disclosure is an in-vehicle electrical component circuit unit including: an electrically insulative holding body configured to hold a circuit member; a plate wall portion configured to cover a casing through hole provided in a casing of an in-vehicle electrical component; a connector including a connection member that protrudes toward two sides in a plate thickness direction of the plate wall portion while held by the plate wall portion; and an annular sealing member that is provided on a first surface, which is a surface of the plate wall portion that is to be attached to the casing, and is configured to come into contact with a peripheral edge of the casing through hole, wherein a portion of the connection member that protrudes on a first surface side corresponding to the first surface of the plate wall portion includes a circuit-side connection portion, the circuit-side connection portion is detachably connectable to the circuit member, and the circuit-side connection portion of the connection member is inserted into the casing through hole from outside the casing and connected to the circuit member, and the sealing member of the wall plate portion comes into contact with the peripheral edge of the casing through hole from outside of the casing. 
     With the in-vehicle electrical component circuit unit of the present disclosure, the connector is provided in the plate wall portion that covers the casing through hole provided in the casing, and the circuit-side connection portion of the connection member of the connector that protrudes toward the first surface side of the plate wall portion can be detachably connected to the circuit member. Thus, the connector can be a constituent element on the in-vehicle electrical component circuit unit side, and the structure of the casing can be simplified. Furthermore, the annular sealing member that comes into contact with the peripheral edge of the casing through hole is provided on the first surface of the plate wall portion, and the circuit-side connection portion of the connection member of the connector held by the plate wall portion is inserted into the casing through hole from outside the casing, and connected directly to the circuit member housed in the casing. Thus, compared to a conventional structure, incremental increases in tolerance can be reduced. In addition, the sealing member of the plate wall portion comes into contact with the peripheral edge of the casing through hole from the outside of the casing. The annular sealing member constitutes a so-called surface seal that is sandwiched between opposing surfaces between the peripheral edge of the casing through hole and the plate wall portion. Thus, it is possible to maintain the water-proofness of the casing through hole, while also absorbing tolerance of the connection position between the connector and the circuit unit in two directions that are orthogonal to the direction in which the plate wall portion is attached to the casing using elastic deformation of the sealing member. As a result, positional shifting caused by tolerance of the connection position between the connector and the circuit unit can be reduced. 
     Note that the connection member of the connector may be a coated electrical wire that includes a circuit-side connection portion at one end thereof, or a bus bar in which a circuit-side connection portion is integrated with one end portion thereof. 
     (2) It is preferable that the connection member of the connector is constituted by a bus bar, the circuit-side connection portion is provided at a protruding end portion on the first surface side of the plate wall portion, and an external connection portion is provided at a protruding end portion of the plate wall portion on a second surface side corresponding to a second surface of the plate wall portion that is opposite to the first surface. With the in-vehicle electrical component circuit unit of the present disclosure, positional shifting caused by tolerance of the connection position between the connector and the circuit unit can be reduced, and thus the connection member of the connector can also be employed for a bus bar in place of a conventional coated electrical wire. As a result, the length of the connection member can be reduced, and the casing and the circuit unit can be brought closer to each other, which contribute to a reduction in the size of the in-vehicle electrical component. 
     (3) It is preferable that the connector includes a hood portion that is provided on the second surface of the plate wall portion and protrudes toward the second surface side while surrounding the external connection portion. The connector includes the hood portion that protrudes toward the second surface side of the plate wall portion, and the external connection portion is disposed inside the hood portion, and thus a connector that can be stably connected to an external partner connector can be provided on the plate wall portion. 
     (4) It is preferable that the circuit-side connection portion is configured to be bolted to the connection member, and a bolt insertion hole provided in the circuit-side connection portion has an elongated shape that is elongated in a direction in which the plate wall portion is attached to the casing. Bolting allows the circuit-side connection portion to be detachably attached to the circuit member, and thus the connection between the connector and the circuit unit can be kept stable. Furthermore, the bolt insertion hole provided in the circuit-side connection portion includes an elongated hole that is elongated in the direction in which the plate wall portion is attached to the casing. Thus, in addition to the two directions orthogonal to the direction in which the plate wall portion is attached to the casing, the sealing member can also absorb tolerance of the connection position between the connector and the circuit unit in the direction in which the plate wall portion is attached to the casing. 
     (5) It is preferable that the in-vehicle electrical component circuit unit further includes a base plate portion configured to be placed onto and fixed to the holding body, wherein the base plate portion is made of a material with higher heat conductivity than the holding body. The base plate portion is made of a material that has higher heat conductivity than the holding body, and thus heat transferred to the holding body via the base plate portion can be dissipated from the circuit member including heat generating components such as a relay and a fuse. 
     (6) It is preferable that the base plate portion is provided with a support leg portion that protrudes downward from the base plate portion. Due to provision of the support leg portion provided on the base plate portion, the circuit can be placed onto other components housed in the in-vehicle electrical component. Also, changing the protruding length of the leg support portion makes for easy adjustment of the height position of the plate wall portion relative to the casing through hole, and a highly universal in-vehicle electrical component circuit unit that is applicable to casing through holes provided at various height positions can be provided. 
     Detailed Description of Embodiment of the Present Disclosure 
     Specific examples of an in-vehicle electrical component circuit unit of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these illustrative examples, but is indicated by the claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein. 
     Embodiment 1 
     Embodiment 1 of the present disclosure will be described below with reference to  FIGS.  1  to  7   . An in-vehicle electrical component circuit unit  10  is for installation in a vehicle such as an electric car or a hybrid car (not shown), and supplies power from a power source such as a battery (not shown) to a load such as a motor (not shown), and performs control of such power supply. Note that the in-vehicle electrical component circuit unit  10  can be positioned in any orientation, but in the following description, the Z direction is the upward direction, the Y direction is the rightward direction, and the X direction is the forward direction. Also, there may be cases where only some members among a plurality of identical members are given reference numerals while reference numerals are omitted for the other members. 
     In-Vehicle Electrical Component Circuit Unit  10   
     The in-vehicle electrical component circuit unit  10  includes a circuit member  12  and an electrically insulative holding body  14  that holds the circuit member  12 . Also, the in-vehicle electrical component circuit unit  10  includes a later-described plate wall portion  104 , a connector  118 , and a sealing member  126 . 
     Circuit Member  12   
     In Embodiment 1, the circuit member  12  includes positive electrode-side and negative electrode-side relays  16   a  and  16   b , bus bars  18   a  and  18   b  that are electrically connected to the positive electrode-side relay  16   a , bus bars  20   a  and  20   b  that are electrically connected to the negative electrode-side relay  16   b , a pre-charge resistor  22 , and a pre-charge relay  24 . The pre-charge resistor  22  and the pre-charge relay  24  are electrically connected to either the positive electrode-side or the negative-electrode side relay (for example, the positive electrode-side relay  16   a ) to form a pre-charge circuit  26 . Note that an unshown pre-charge resistor and pre-charge relay may also be electrically connected to the other relay (for example, the negative electrode-side relay  16   b ) to form a pre-charge circuit. 
     The positive electrode-side and negative electrode-side relays  16   a  and  16   b  are provided facing away from each other. In Embodiment 1, the positive electrode-side and negative electrode-side relays  16   a  and  16   b  each face outward in the left-right direction. The relays  16   a  and  16   b  each include a relay main body  28  that has a hollow parallelopiped shape. Each outer end surface in the left-right direction of the relays  16   a  and  16   b  serving as the front surface thereof is provided with a pair of connection portions  30   a  and  30   b  in the form of through holes that extend through the corresponding relay main body  28  in the thickness direction thereof, and that are formed spaced apart from each other in the front-rear direction. Also, each relay main body  28  is provided with leg portions  32  that protrude outward in the front-rear direction. Each leg portion  32  is provided with a bolt insertion hole  34  extending therethrough in the up-down direction. 
     Note that the relays  16   a  and  16   b  and the pre-charge relay  24  are relays in which a contact portion is switched ON/OFF by moving the contact portion with use of the conductive state of an exciting coil. The relays  16   a  and  16   b  and the pre-charge relay  24  are turned ON/OFF by a control circuit in a wiring component  174  provided in a later-described in-vehicle electrical component  130 . 
     The bus bars  18   a  and  20   a  are electrically connected to the front connection portions  30   a  of the relays  16   a  and  16   b , respectively, and extend forward. The bus bars  18   b  and  20   b  are electrically connected to the rear connection portions  30   b  of the relays  16   a  and  16   b , respectively, and extend rearward. 
     The bus bars  18   a ,  18   b ,  20   a , and  20   b  are each formed by a metal plate member that has conductive properties, and are formed by folding the metal plate member into a predetermined shape through pressing or the like. The front end portions of the front bus bars  18   a  and  20   a  are folded inward in the left-right direction so as to approach each other, and front connection portions  38  are respectively formed by the folded portions. Also, the rear end portions of the rear bus bars  18   b  and  20   b  are folded inward in the left-right direction so as to approach each other, and rear connection portions  44  are respectively formed by the folded portions. Note that the front connection portions  38  and the rear connection portions  44  are respectively provided with bolt insertion holes  46  and bolt insertion holes  48  that extend therethrough in the thickness direction (up-down direction). Specifically, in Embodiment 1, the bolt insertion holes  46  and  48  each have a substantially perfect circle shape. 
     By bolting the rear end portions of the front bus bars  18   a  and  20   a  and the connection portions  30   a  of the relays  16   a  and  16   b  to each other, the relays  16   a  and  16   b  and the bus bars  18   a  and  20   a  are electrically connected to each other. Also, by bolting the front end portions of the rear bus bars  18   b  and  20   b  and the connection portions  30   b  of the relays  16   a  and  16   b  to each other, the relays  16   a  and  16   b  and the bus bars  18   b  and  20   b  are electrically connected to each other. 
     Holding Body  14   
     In Embodiment 1, the holding member  14  for holding the circuit member  12  has a substantially hollow box shape. Specifically, in Embodiment 1, the holding body  14  includes a lower case  50  that is open upward and an upper case  52  that is open downward. Note that the holding body  14  may house un-shown bus bars that connect the relays  16   a  and  16   b  and the pre-charge circuit  26 , an un-shown bus bar or the like for connection inside the pre-charge circuit  26 , or the like. The upper and lower cases  50  and  52  may be made of a hard synthetic resin, for example. 
     The lower case  50  has a substantially rectangular box shape overall. In Embodiment 1, the four corners of the lower case  50  are each provided with a notch-shaped recess  58 . 
     The upper case  52  has a substantially rectangular box shape overall. In Embodiment 1, the four corners of the upper case  52  are each provided with a bolt insertion hole  64  that extends therethrough in the up-down direction. Also, the rear portion of the upper case  52  is provided with a pre-charge resistor mounting portion  66  and a pre-charge relay mounting portion  68  that are open upward and are for respectively housing the pre-charge resistor  22  and the pre-charge relay  24 . 
     The aforementioned holding body  14  is formed by placing the upper case  52  onto the lower case  50  and fixing the upper case  52  to the lower case  50 . Note that the fixing structure between the lower case  50  and the upper case  52  is not limited, and a fixing structure realized by press-fitting, recession/projection fitting, or the like may be employed. 
     Furthermore, substantially tubular relay fixing portions  70  that protrude upward are provided on the upper case  52  at positions corresponding to the leg portions  32  of the relays  16   a  and  16   b . Also, substantially tubular rear bus bar fixing portions  74  that protrude upward are provided on the rear end portion of the upper case  52  at positions that correspond to the rear connection portions  44  of the rear bus bars  18   b  and  20   b . Furthermore, substantially tubular front bus bar fixing portions  78  that protrude upward are provided on the front end portion of the upper case  52  at positions that correspond to the front side connection portions  38  of the front bus bars  18   a  and  20   a . 
     By bolting the leg portions  32  of the relays  16   a  and  16   b  and the relay fixing portions  70  to each other, the relays  16   a  and  16   b  are held by the holding body  14 . Also, by bolting the rear connection portions  44  and the rear bus bar fixing portions  74  to each other, the rear bus bars  18   b  and  20   b  are held by the holding body  14 . At this time, terminal portions (not shown) provided at an end portion of a later-described wire harness  180  are overlaid onto the rear connection portions  44  of the bus bars  18   b  and  20   b , and fastened thereto using bolts. Thus, the rear bus bars  18   b  and  20   b  and the wire harness  180  are electrically connected to each other. Furthermore, by bolting the front connection portions  38  and the front bus bar fixing portions  78  to each other, the front bus bars  18   a  and  20   a  are held by the holding body  14 . At this time, circuit-side connection portions  120  of the later-described connector  118  are respectively overlaid onto the front connection portions  38  of the bus bars  18   a  and  20   a , and fastened thereto using bolts. Accordingly, the front bus bars  18   a  and  20   a  and the connector  118  are electrically connected to each other. 
     Base Plate Portion  88   
     As previously described, the holding body  14  is placed onto and fixed to a base plate portion  88 . The base plate portion  88  has a substantially rectangular plate shape overall. The base plate portion  88  is preferably made of a material with higher heat conductivity than the holding body  14 , and is made of a metal such as aluminum, an aluminum alloy, or the like. 
     In Embodiment 1, the four corners of the base plate portion  88  are each provided with a substantially tubular holding body fixing portion  90  that protrudes upward. By placing the holding body  14  onto the holding body fixing portions  90  and bolting them to each other, the holding body  14  and the base plate portion  88  are fixed to each other. 
     Support Leg Portion  96   
     The base portion  88  is provided with a support leg portion  96  that protrudes downward (direction opposite to Z direction arrow). In Embodiment 1, the support leg portion  96  is a substantially gutter-shaped member that extends in the left-right direction. That is, the support leg portion  96  includes a substantially rectangular upper bottom wall  98  that extends in the left-right direction, and a pair of side walls  100  that protrude downward from the front and rear ends of the upper bottom wall  98 . Also, the lower ends of the side walls  100  are each provided with a flange-shaped portion  102  that protrudes outward in the front-rear direction. The support leg portion  96  may be made of metal or a hard synthetic resin, for example. 
     By bolting the central portion of the base plate portion  88  in the front-rear direction and the upper bottom wall  98  of the support leg portion  96  to each other, the base plate portion  88  and the support leg portion  96  are fixed to each other. 
     Plate Wall Portion  104  and Connector  118   
     A casing through-hole  156  provided on the front side of a later-described casing  132  is configured such that it can be covered by the substantially rectangular plate wall portion  104 . In other words, the plate wall portion  104  is greater in size than the casing through-hole  156 . The plate wall portion  104  is provided with bolt insertion holes  106  that extend therethrough in the thickness direction thereof (front-rear direction) at positions that correspond to bolt holes  158  provided around the casing through-hole  156 . 
     The plate wall portion  104  is overlaid onto the casing  132  (upper cover  136 ) from the outside and attached thereto. Accordingly, the rear end surface of the plate wall portion  104  is a first surface  110  that is overlaid onto and attached to the casing  132 . Also, the front end surface of the plate wall portion  104  on the side opposite to the first surface  110  is a second surface  112 . 
     Furthermore, the plate wall portion  104  includes a connection member  114  that protrudes toward both sides in the thickness direction (the first surface  110  side and the second surface  112  side). In Embodiment 1, a pair of connection members  114  that are spaced apart from one another in the left-right direction are provided. Specifically, as shown in  FIGS.  6  and  7   , the plate wall portion  104  is provided with a pair of through holes  116  that are substantially rectangular and are distanced from one another in the left-right direction. By press-fitting the connection members  114  into the through holes  116 , the connection members  114  are held by the plate wall portion  104 . Thus, a connector  118  including the plate wall portion  104  and the connection members  114  is configured. 
     Each connection member  114  is formed by a bus bar made of a conductive metal. Specifically, each connection member  114  is formed by bending, for example, a metal plate member through pressing or the like. In Embodiment 1, the rear end portion of each connection member  114  is folded outward in the direction in which the connection members  114  oppose each other (outward in the left-right direction) so as to extend horizontally. The rear end portions of the connection members  114 , that is, the protruding end portions on the first surface side  110  (rear side) of the plate wall portion  104 , respectively form the circuit-side connection portions  120 . Each circuit-side connection portion  120  is provided with an insertion hole  121  that extends therethrough in the thickness direction (up-down direction) thereof. Specifically, in Embodiment 1, as also shown in  FIG.  7   , the bolt insertion holes  121  are substantially perfectly circular in shape. Also, the front end portions of the connection members  114 , that is, the protruding end portions on the second surface  112  side, form external connection portions  122 . 
     The circuit-side connection portions  120  are overlaid onto the front connection portions  38  at the front ends of the front bus bars  18   a  and  20   a  when the plate wall portion  104  is fixed to the casing  132  (upper cover  136 ). By inserting bolts into the bolt insertion holes  46  of the front connection portions  38  and the bolt insertion holes  121  of the circuit-side connection portions  120  and fastening the front connection portions  38  and the circuit-side connection portions  120  to each other, the front bus bars  18   a  and  20   a  and the connection members  114  are electrically connected to each other. Accordingly, in Embodiment 1, the in-vehicle electrical component circuit unit  10  includes the plate wall portion  104  and the connector  118 . Also, by unscrewing the bolts, the front connection portions  38  and the circuit-side connection portions  120  are disconnected, and thus the front connection portions  38  (circuit member  12 ) and the circuit-side connection portions  120  can be detachably connected to each other. 
     Furthermore, as also shown in  FIG.  6   , the outer peripheral portion of the first surface  110  that is the rear end surface of the plate wall portion  104  is provided with a substantially annular groove  124  that is open rearward. An annular sealing member  126  that is made of rubber, an elastomer, or the like is provided in the groove  124 . Specifically, by overlaying the plate wall portion  104  onto the casing  132  (surrounding edge of later-described casing through-hole  156 ) and fixing the plate wall portion  104  thereto, the sealing member  126  is compressed from both the front and back between the plate wall portion  104  and the casing  132 , and thus the space between the casing  132  (casing through hole  156 ) and the plate wall portion  104  is sealed in a liquid-tight manner. 
     Furthermore, in Embodiment 1, the second surface side  112  (front side) of the plate wall portion  104  is provided with a hood  128  that protrudes on the second surface  112  side (front side) while surrounding the connection members  114  on the outer peripheral side of the connection members  114 . Specifically, in Embodiment 1, the hood  128  protrudes forward beyond the external connection portions  122 , which are the front end portions of the connection members  114 . 
     In-Vehicle Electrical Component  130   
     As previously described, the in-vehicle electrical component  130  shown in  FIG.  3    and the like includes the in-vehicle electrical component circuit unit  10 . Specifically, the in-vehicle electrical component circuit unit  10  is housed in the casing  132  of the in-vehicle electrical component  130 . 
     Casing  132   
     In Embodiment 1, the casing can be divided in the up-down direction. Specifically, the casing  132  includes a lower cover  134  that is open upward and an upper cover  136  that is open downward. Note that the lower and upper covers  134  and  136  are made of, for example, a metal such as aluminum or an aluminum alloy, a hard synthetic resin, or the like. 
     The lower cover  134  has a substantially rectangular box shape overall. Specifically, the lower cover  134  includes a substantially rectangular bottom wall  138  and a peripheral wall  140  that protrudes upward from the outer peripheral edge portion of the bottom wall  138 . Also, the upper end of the peripheral wall  140  is provided with a substantially annular lower cover flange portion  142  that protrudes circumferentially outward. Furthermore, the lower cover flange portion  142  is provided with an annular groove  144  that is open upward and extends over the entire lower cover flange portion  142  in a circumferential direction thereof. 
     Furthermore, the bottom wall  138  of the lower cover  134  is provided with substantially tubular support leg fixing portions  146  that protrude upward. By bolting the flange-shaped portions  102  of the support leg portions  96  and the support leg fixing portions  146  to each other, the support leg portions  96  are fixed to the lower cover  134 . 
     The upper cover  136  has a substantially rectangular box shape overall. Specifically, the upper cover  136  includes a substantially rectangular upper bottom wall  148  and a peripheral wall  150  that protrudes downward from the outer peripheral edge portion of the upper bottom wall  148 . Also, the bottom end of the peripheral wall  150  is provided with a substantially annular upper cover flange portion  152  that protrudes to the outer peripheral side. Furthermore, by bolting the lower cover flange portion  142  and the upper cover flange portion  152  to each other, the lower cover  134  and the upper cover  136  are fixed to each other. 
     Note that an annular sealing member  154  that is an elastic body made of rubber, an elastomer, or the like is provided in the groove  144  in the space between overlapping surfaces between the lower cover flange portion  142  and the upper cover flange portion  152 . Thus, the sealing member  154  is compressed in the up-down direction between the lower cover flange portion  142  and the upper cover flange portion  152  when the lower cover  134  and the upper cover  136  are fixed to one another, and thus the space between the lower cover  134  and the upper cover  136  is sealed in a liquid-tight manner. 
     The casing through hole  156  is formed in the front portion of the peripheral wall  150  of the upper cover  136  so as to extend therethrough in the thickness direction thereof (front-rear direction). The casing through hole  156  is substantially rectangular in shape. The bolt holes  158  are provided around the casing through hole  156 . Also, a through window  160  is formed in the front portion of the upper bottom wall  148  so as to extend therethrough in the thickness direction thereof (up-down direction). A plurality of bolt holes  162  are provided around the through window  160 . Furthermore, an annular groove  164  is formed on the outer peripheral side of the bolt holes  162 . 
     A substantially rectangular cover  166  that is larger in size than the through window  160  is overlaid onto the through window  160  from above and fixed to the peripheral edge portion of the through window  160 . Specifically, the cover  166  is provided with bolt insertion holes  168  that extend therethrough in the thickness direction of the cover  166  (up-down direction) at positions that correspond to the bolt holes  162  around the through window  160 . By matching the positions of the bolt holes  162  around the through window  160  with the bolt insertion holes  168  of the cover  166  and inserting bolts  170  and fastening the bolts  170 , the cover  166  can be fixed to the through window  160  from above the upper cover  136 . 
     Note that an annular sealing member  172  that is an elastic body made of rubber, an elastomer, or the like is provided in the groove  164  between overlapping surfaces between the upper cover  136  and the cover  166 . Accordingly, the sealing member  172  is compressed in the up-down direction when the upper cover  136  and the cover  166  are fixed to one another, and thus the space between the upper cover  136  and the cover  166  is sealed in a liquid-tight manner. 
     Note that, in Embodiment 1, the wiring component  174  is provided in the region covered by the support leg portion  96  and the lower cover  134  inside the casing  132 . The wiring component  174  is an electrical component that includes a control circuit or the like. In Embodiment 1, the in-vehicle electrical component  130  includes the wiring component  174 . 
     Specifically, in Embodiment 1, a wire harness insertion hole  176  is formed in a portion of the peripheral wall  140  of the lower cover  134  so as to extend therethrough in the thickness direction of the peripheral wall  140 . A substantially cylindrical rubber grommet  178  is fitted into the wire harness insertion hole  176 , and the wire harness  180  is inserted into the casing  132  via the through hole provided in the center of the grommet  178 . The wire harness  180  is electrically connected to the in-vehicle electrical component circuit unit  10  and the wiring component  174 , and supplies power to the in-vehicle electrical component circuit unit  10  and the wiring component  174 . Also, the grommet  178  blocks water from entering the casing  132  via the wire harness insertion hole  176 . 
     Assembly of In-Vehicle Electrical Component Circuit Unit  10  and In-Vehicle Electrical Component  130   
     Next, a specific example of assembly of the in-vehicle electrical component circuit unit  10  will be described. Note that the assembly of the in-vehicle electrical component circuit unit  10  is not limited to the following. 
     First, the lower case  50  and the upper case  52  constituting the holding body  14  are prepared. As needed, bus bars for connection of the relays  16   a  and  16   b  to the pre-charge circuit  26  and a bus bar for connection inside the pre-charge circuit  26  are housed between the lower case  50  and the upper case  52 . Then, the upper case  52  is placed on and fixed to the lower case  50  to form the holding body  14 . 
     Next, the pre-charge resistor  22  and the pre-charge relay  24  are respectively mounted to the pre-charge resistor mounting portion  66  and the pre-charge relay mounting portion  68  provided on the upper surface of the holding body  14 . Then, the relays  16   a  and  16   b  and the bus bars  18   a ,  18   b ,  20   a , and  20   b  are placed on the upper surface of the holding body  14  and fixed with bolts. When fixing the rear connection portions  44 , which are the rear end portions of the bus bars  18   b  and  20   b , using bolts, the terminal portions provided at the end portion of the wire harness  180  are overlaid onto and fastened to the rear connection portions  44 . 
     Then, once the base plate portion  88  and the support leg portion  96  have been prepared, the holding body  14  holding the circuit member  12  is placed onto and fixed to the base plate portion  88  using bolts. Next, the base plate portion  88  is overlaid onto the support leg portion  96  and fixed thereto using bolts. Accordingly, the circuit member  12 , the holding body  14 , the base plate portion  88 , and the support leg portion  96  are fixed as a single body. Note that the order in which the relays  16   a  and  16   b , the bus bars  18   a ,  18   b ,  20   a , and  20   b , the pre-charge resistor  22 , and the pre-charge relay  24  are fixed in the holding body  14  is not limited. Also, the order in which the circuit member  12 , the holding body  14 , the base plate portion  88 , and the support leg portion  96  are fixed is not limited. 
     Then, the lower cover  134 , the upper cover  136 , and the wiring component  174  constituting the casing  132  are prepared. The wiring component  174  connected to the wire harness  180  is placed on the bottom wall  138  of the lower cover  134 , and the support leg portion  96  is placed over the wiring component  174  from above and fixed thereto using bolts. Then, the upper cover  136  is placed over the circuit member  12  from above, and the lower cover  134  and the upper cover  136  are fixed to each other using bolts. Thus, the circuit member  12 , the holding body  14 , the base plate portion  88 , the support leg portion  96 , and the wiring component  174  are housed in the casing  132 . 
     Next, the connector  118  is prepared. The connector  118  is inserted into the casing through hole  156  from outside the casing  132 , and the outer peripheral edge portion of the plate wall portion  104  is overlaid onto the peripheral edge of the casing through hole  156 . Then, the positions of the bolt insertion holes  106  of the plate wall portion  104  and the bolt holes  158  around the casing through hole  156  are matched with each other. Next, by inserting bolts  108  into the bolt holes  158  and the bolt insertion holes  106  and fastening them, the plate wall portion  104  is fixedly attached to the casing  132 , and the casing through hole  156  is covered by the plate wall portion  104 . At this time, the front connection portions  38  of the front bus bars  18   a  and  20   a  are overlaid onto the circuit-side connection portions  120  of the connector  118 . A jig is inserted through the through window  160  formed on the upper side of the casing  132  to bolt the front connection portions  38  and the circuit-side connection portions  120  to each other. Accordingly, the in-vehicle electrical component circuit unit  10  is complete. Next, by placing the cover  166  onto the upper cover  136  from above and fixing the cover  166  using the bolts  170 , the through window  160  is closed off. Thus, the in-vehicle electrical component  130  is complete. 
     In the in-vehicle electrical component circuit unit  10  with the above-described structure, the circuit-side connection portions  120  of the connector  118  and the front connection portions  38  provided at the front end portions of the circuit member  12  are detachably connected to each other by bolts. Thus, the in-vehicle electrical component circuit unit  10  can include the connector  118 . In other words, the in-vehicle electrical component circuit unit  10  of the present disclosure can be applied to the casing  132  including the casing through hole  156 , the design freedom of the casing  132  can be increased, and a reduction in the size and simplification of the casing  132  as well as the in-vehicle electrical component  130  can be realized, for example. 
     Also, as shown in  FIG.  6   , the annular sealing member  126  made of an elastic material is provided between the plate wall portion  104  and the casing  132  (upper cover  136 ). Accordingly, water can be blocked from entering between the plate wall portion  104  and the casing  132 . Furthermore, the annular sealing member  126  forms a so-called surface seal that is sandwiched between opposing surfaces of the plate wall portion  104  and the casing  132 . Thus, the attachment tolerance in two directions (Y and Z directions) that are orthogonal to the direction in which the plate wall portion  104  is attached to the casing  132  is absorbed by elastic deformation of the sealing member  126 . Accordingly, connection between the connector  118  and the circuit member  12 , specifically, bolting between the circuit-side connection portions  120  and the front connection portions  38  can be more reliably achieved. 
     Furthermore, as described above, the tolerance between the connector  118  and the circuit member  12  is absorbed by elastic deformation of the sealing member  126 . Therefore, with Embodiment 1, the connection members  114  of the connector  118  can be formed using bus bars with less elasticity than a coated electrical wire, for example. Specifically, the aforementioned effect of absorbing tolerance also makes it possible to make the connection members  114  of the connector  118  shorter, for example. Accordingly, the in-vehicle electrical component circuit unit  10  can also be installed closer to the casing through hole  156  of the casing  132 , and thus the size of the casing  132  as well as the in-vehicle electrical component  130  can also be reduced. 
     Also, in Embodiment 1, the hood portion  128  on the second surface  112  (front end surface) side of the plate wall portion  104  surrounds the external connection portions  122  of the connection members  114 , and thus the likelihood of unintentional contact with the external connection portions  122  can be reduced. Specifically, in Embodiment 1, the hood  128  protrudes outward (forward) beyond the external connection portions  122 , and thus the likelihood of unintentional contact with the external connection portions  122  can be reduced even more. 
     Furthermore, in Embodiment 1, the base plate portion  88  for placement of the holding body  14  is made of a material with higher heat conductivity than that of the holding body  14 , and thus heat generated by the circuit member  12  is transferred to the base plate portion  88  via the holding body  14  and dissipated from the base plate portion  88 . Specifically, in Embodiment 1, the holding body  14  has a hollow structure, and the holding body  14  and the base plate portion  88  are arranged with a gap therebetween, and thus heat can be more steadily dissipated from the holding body  14  and the base plate portion  88 . 
     Furthermore, in Embodiment 1, the support leg portion  96  protruding downward from the base plate portion  88  is provided. In other words, by adjusting the height of the support leg portion  96 , the height position of the base plate portion  88  as well as the circuit member  12  can also be adjusted, and thus design freedom regarding the shape of the casing  132  can be increased even more. Also, in Embodiment 1, the wiring member  174  can also be positioned below the support leg portion  96 . In other words, adjusting the height of the support leg portion  96  makes it possible to avoid contact between the base plate portion  88  (upper bottom wall  98 ) and the wiring member  174 , and also suppress the transfer of heat to the wiring member  174 . 
     Other Embodiments 
     The technology described in the present specification is not limited to the embodiments thus described using the above description and drawings, and embodiments such as the following are to be included in the technical scope of the present specification, for example. 
     (1)  FIG.  8    shows a connector  190  included in an in-vehicle electrical component circuit unit according to a different aspect of the present disclosure. Note that, in the in-vehicle electrical component circuit unit of the present aspect, structures other than that of the connector  190  are the same as those in Embodiment 1, and thus a detailed description is omitted. In the present aspect, bolt insertion holes  192  in the circuit-side connection portions  120  have an elongated hole shape (ellipse shape) that is elongated in the front-rear direction, which is the direction in which the plate wall portion  104  is attached to the casing  132 . Accordingly, when connecting the connector  190  and the circuit member  12 , specifically, when fixing the circuit-side connection portions  120  to the front connection portions  38  using bolts, attachment tolerance in the direction in which the plate wall portion  104  is attached to the casing  132  can be absorbed by the annular sealing member  126  in addition to tolerance in the Y and Z directions. Thus, tolerance between the connector  190  and the circuit member  12  can be more reliably absorbed. Note that, in place of or in addition to the bolt insertion holes  192  in the circuit-side connection portions  120 , the bolt insertion holes  46  of the front connection portions  38  may have an elongated hole shape (ellipse shape) that is elongated in the front-rear direction. 
     (2) In Embodiment 1, an example of the in-vehicle electrical component  130  was described in which the wiring component  174  and the in-vehicle electrical component circuit unit  10  of the present disclosure are housed inside the casing  132 , but the present invention is not limited to this. Instead of a wiring component, the in-vehicle electrical component may be a battery pack housing a battery, for example. In this case, there is no need to provide a wire harness or wire harness insertion hole that extend through the casing. 
     (3) The casing is not limited to any specific shape, provided that a casing through hole is provided. For example, in Embodiment 1, the casing through hole  156  is provided in the upper cover  136 , but the casing through hole  156  may be provided in the lower cover. Note that the shapes of the casing through hole and the plate wall portion that covers the casing through hole are not limited to a substantially rectangular shape as described in Embodiment 1, and may have a polygonal shape such as a triangular shape, or a circular shape (including a perfect circle, ellipse, oval, semi-circle, and the like). 
     (4) In Embodiment 1, the support leg portion  96  is substantially gutter-shaped, and the side walls  100  protrude downward from the front and rear ends of the upper bottom wall  98 , but a configuration is possible where side walls protrude downward from the base plate portion, and the side walls form the support leg portion. Also, the support leg portion and the base plate portion may be formed as separate bodies and then fixed to one another as described in Embodiment 1, or formed as one piece. Note that the base plate portion and the support leg portion are not essential to the present disclosure. 
     (5) In Embodiment 1, the support leg portion  96  is fixed to the bottom wall  138  of the casing  132  (lower cover  134 ), but the present invention is not limited to this aspect. The support leg portion can be fixed at an appropriate location, such as being fixed to the peripheral wall of the upper cover or the lower cover of the casing. 
     
       
         
           
               
               
             
               
                 List of Reference Numerals 
               
             
            
               
                 
                   10 
                 
                 In-vehicle electrical component circuit unit 
               
               
                 
                   12 
                 
                 Circuit member 
               
               
                 
                   14 
                 
                 Holding body 
               
               
                 
                   16 
                   a 
                 
                 (Positive electrode-side) relay 
               
               
                 
                   16 
                   b 
                 
                 (Negative electrode-side) relay 
               
               
                   18   a ,  18   b   
                 Bus bar (connected to positive electrode-side relay) 
               
               
                   20   a ,  20   b   
                 Bus bar (connected to negative electrode-side relay) 
               
               
                 
                   22 
                 
                 Pre-charge resistor 
               
               
                 
                   24 
                 
                 Pre-charge relay 
               
               
                 
                   26 
                 
                 Pre-charge circuit 
               
               
                 
                   28 
                 
                 Relay main body 
               
               
                   30   a ,  30   b   
                 Connection portion 
               
               
                 
                   32 
                 
                 Leg portion 
               
               
                 
                   34 
                 
                 Bolt insertion hole 
               
               
                 
                   38 
                 
                 Front connection portion 
               
               
                 
                   44 
                 
                 Rear connection portion 
               
               
                   46 ,  48   
                 Bolt insertion hole 
               
               
                 
                   50 
                 
                 Lower case 
               
               
                 
                   52 
                 
                 Upper case 
               
               
                 
                   58 
                 
                 Recess 
               
               
                 
                   64 
                 
                 Bolt insertion hole 
               
               
                 
                   66 
                 
                 Pre-charge resistor mounting portion 
               
               
                 
                   68 
                 
                 Pre-charge relay mounting portion 
               
               
                 
                   70 
                 
                 Relay fixing portion 
               
               
                 
                   74 
                 
                 Rear bus bar fixing portion 
               
               
                 
                   78 
                 
                 Front bus bar fixing portion 
               
               
                 
                   88 
                 
                 Base plate portion 
               
               
                 
                   90 
                 
                 Holding body fixing portion 
               
               
                 
                   96 
                 
                 Support leg portion 
               
               
                 
                   98 
                 
                 Upper bottom wall 
               
               
                 
                   100 
                 
                 Side wall 
               
               
                 
                   102 
                 
                 Flange-shaped portion 
               
               
                 
                   104 
                 
                 Plate wall portion 
               
               
                 
                   106 
                 
                 Bolt insertion hole 
               
               
                 
                   108 
                 
                 Bolt 
               
               
                 
                   110 
                 
                 First surface 
               
               
                 
                   112 
                 
                 Second surface 
               
               
                 
                   114 
                 
                 Connection member 
               
               
                 
                   116 
                 
                 Through hole 
               
               
                 
                   118 
                 
                 Connector 
               
               
                 
                   120 
                 
                 Circuit-side connection portion 
               
               
                 
                   121 
                 
                 Bolt insertion hole 
               
               
                 
                   122 
                 
                 External connection portion 
               
               
                 
                   124 
                 
                 Groove 
               
               
                 
                   126 
                 
                 Sealing member 
               
               
                 
                   128 
                 
                 Hood portion 
               
               
                 
                   130 
                 
                 In-vehicle component 
               
               
                 
                   132 
                 
                 Casing 
               
               
                 
                   134 
                 
                 Lower cover 
               
               
                 
                   136 
                 
                 Upper cover 
               
               
                 
                   138 
                 
                 Bottom wall 
               
               
                 
                   140 
                 
                 Peripheral wall 
               
               
                 
                   142 
                 
                 Lower cover flange portion 
               
               
                 
                   144 
                 
                 Groove 
               
               
                 
                   146 
                 
                 Support leg fixing portion 
               
               
                 
                   148 
                 
                 Upper bottom wall 
               
               
                 
                   150 
                 
                 Peripheral wall 
               
               
                 
                   152 
                 
                 Upper cover flange portion 
               
               
                 
                   154 
                 
                 Sealing member 
               
               
                 
                   156 
                 
                 Casing through hole 
               
               
                 
                   158 
                 
                 Bolt hole 
               
               
                 
                   160 
                 
                 Through window 
               
               
                 
                   162 
                 
                 Bolt hole 
               
               
                 
                   164 
                 
                 Groove 
               
               
                 
                   166 
                 
                 Cover 
               
               
                 
                   168 
                 
                 Bolt insertion hole 
               
               
                 
                   170 
                 
                 Bolt 
               
               
                 
                   172 
                 
                 Sealing member 
               
               
                 
                   174 
                 
                 Wiring component 
               
               
                 
                   176 
                 
                 Wire harness insertion hole 
               
               
                 
                   178 
                 
                 Grommet 
               
               
                 
                   180 
                 
                 Wire harness 
               
               
                 
                   190 
                 
                 Connector 
               
               
                 
                   192 
                 
                 Bolt insertion hole