Circuit unit

Abstract

Disclosed is a circuit unit with a novel structure, which can suppress the enlargement and high cost of the circuit unit and implement a countermeasure for the heating of the resistor. The circuit unit (10) includes: a wiring member (14); a lower shell (18) for holding the wiring member (14); an upper shell (16) for covering the lower shell (18); and resistors (60a, 60b) connected to the wiring member (14). The upper shell (16) has a wall portion (82) surrounding the resistors (60a, 60b). In a first orthogonal direction perpendicular to the longitudinal direction of the resistors (60a, 60b), the distance between the middle portion (64) of the longitudinal direction of the resistors (60a, 60b) and the wall portion (82) of the upper shell (16) is greater than the distance between the end portions (66) of the longitudinal direction of the resistors (60a, 60b) and the wall portion (82) of the upper shell (16).

Description

Technical Field

[0001] The present disclosure relates to a circuit unit. Background Art

[0002] Patent Document 1 discloses a circuit unit that is housed within a vehicle-mounted battery pack housing along with a battery module, a battery control system, and other components. In this circuit unit, a wiring member is housed between an upper housing and a lower housing. Electrical components such as fuses, relays, and resistors held within a cavity in the upper housing are electrically connected to the wiring member.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2018-537940 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the structure of Patent Document 1, since electrical components are housed in a cavity provided in the upper shell, there is only a small gap between the wall portion of the upper shell defining the cavity and the electrical components. Therefore, in a resistor (equivalent to the resistor in the present application) with a large instantaneous heat generation, the heat generated by the resistor may have an adverse effect on the wall portion of the upper shell surrounding the resistor. In this regard, it is considered to form the upper shell with a resin material having a high heat resistance, but an increase in manufacturing cost is inevitable. In addition, it is also considered to increase the heat capacity of the resistor by making the resistor larger without changing the resin material of the upper shell, but as the resistor is larger, the circuit unit as a whole is inevitably larger, which can hardly be said to be a desired countermeasure.

[0008] Therefore, a circuit unit having a novel structure is disclosed, which can suppress an increase in size and cost of the circuit unit and can take measures to counteract heat generation of the resistor.

[0009] Solutions to Problems

[0010] The circuit unit disclosed in the present invention includes: a wiring component; a lower shell that holds the wiring component; an upper shell that covers the lower shell; and a resistor that is connected to the wiring component, the upper shell having a wall portion that surrounds the resistor, and in a first orthogonal direction that is orthogonal to the length direction of the resistor, a separation distance between a middle portion of the resistor in the length direction and the wall portion of the upper shell is greater than a separation distance between both end portions of the resistor in the length direction and the wall portion of the upper shell.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to suppress an increase in size and cost of a circuit unit and to implement a countermeasure against heat generation of a resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is an exploded perspective view of the circuit unit according to the first embodiment.

[0014] Figure 2 yes Figure 1 A top view of the circuit unit is shown.

[0015] Figure 3 yes Figure 2 Sectional view III-III.

[0016] Figure 4 yes Figure 2 IV-IV sectional view of FIG.

[0017] Figure 5 yes Figure 1 The exploded perspective view of the circuit unit shown is a diagram showing a state in which the wiring member and the resistor are assembled to the lower case. DETAILED DESCRIPTION

[0018] <Description of Embodiments of the Present Disclosure>

[0019] First, embodiments of the present disclosure will be described below.

[0020] The circuit unit of the present disclosure,

[0021] (1) It includes: a wiring member; a lower shell for holding the wiring member; an upper shell for covering the lower shell; and a resistor connected to the wiring member, the upper shell having a wall portion surrounding the resistor, and in a first orthogonal direction orthogonal to the length direction of the resistor, a separation distance between a middle portion of the resistor in the length direction and the wall portion of the upper shell is greater than a separation distance between both end portions of the resistor in the length direction and the wall portion of the upper shell.

[0022] According to the circuit unit disclosed herein, in a first orthogonal direction perpendicular to the length direction of the resistor, the distance between the middle portion of the resistor in the length direction and the wall of the upper housing is greater than the distance between the end portions of the resistor in the length direction and the wall of the upper housing. This ensures a greater distance between the middle portion of the resistor in the length direction, where the temperature rises due to heat generation in the resistor, and the wall of the upper housing, and suppresses the adverse effects of the heat generation of the resistor on the upper housing. As a result, countermeasures for resistor heating can be implemented in the circuit unit without using a high-heat-resistant resin material to form the upper housing. Furthermore, there is no need to increase the thermal capacity of the resistor by increasing the size of the resistor, so countermeasures for resistor heating can be implemented without increasing the size of the circuit unit.

[0023] (2) Preferably, in a second orthogonal direction orthogonal to the longitudinal direction, the separation distance between the middle portion of the resistor and the lower shell is greater than the separation distance between the two end portions of the resistor and the lower shell. The separation distance between the middle portion of the resistor and the lower shell in the second orthogonal direction is greater than the separation distance between the two end portions of the resistor and the lower shell in the second orthogonal direction. Therefore, the lower shell side can also be separated to a greater extent from the middle portion of the resistor whose temperature rises due to the heat of the resistor. As a result, the adverse effects of the heat of the resistor on the lower shell can be suppressed, the circuit unit can be prevented from being enlarged and the cost is suppressed, and the heat generation countermeasures of the resistor can be further advantageously implemented in the circuit unit.

[0024] The term "second orthogonal direction" refers to the direction separating the lower housing and the resistor. To distinguish it from the first orthogonal direction, which represents the direction separating the wall of the upper housing and the resistor, it is expressed as "second" for convenience. However, the first and second orthogonal directions may be different directions, such as mutually orthogonal directions, or may be the same direction.

[0025] (3) Preferably, the upper housing includes a pressing portion that contacts the upper surface of the resistor. Even if the distance between the resistor and the upper housing or the lower housing is increased in a direction perpendicular to the longitudinal direction of the resistor, the pressing portion provided on the upper housing can retain the resistor between the upper housing and the lower housing, thereby preventing the resistor from being separated from the wiring member. As a result, both heat dissipation and stable retention of the resistor in the circuit unit can be achieved.

[0026] (4) Preferably, the lower housing has positioning ribs, and the two end portions of the resistor are inserted into the positioning ribs. This is because the two end portions of the resistor are inserted into the positioning ribs, thereby stably holding the resistor in the lower housing. Furthermore, the resistor is also fixed relative to the lower housing by inserting a pair of diagonal portions of the resistor into the positioning ribs, but it is more preferable that all four corners of the resistor are inserted into the positioning ribs.

[0027] (5) Preferably, the middle portion of the resistor is located between a pair of terminals protruding toward the lower surface of the resistor in the longitudinal direction. This is because the area between the pair of terminals of the resistor becomes a heat generating area of ​​the resistor, and thus heat can be effectively dissipated from the middle portion.

[0028] <Details of Embodiments of the Present Disclosure>

[0029] Below, with reference to the attached Figure 1While describing specific examples of the circuit unit of the present disclosure, the present disclosure is not limited to these examples, but is defined by the claims and includes all modifications within the meaning and scope of the claims and equivalents.

[0030] <Implementation Method 1>

[0031] Below, while referring to Figures 1 to 5 The circuit unit 10 of the first embodiment is a power distribution component used in a battery pack of a vehicle. Figure 1 As shown in FIG. 1 , a wiring member 14 is housed in a housing 12. The housing 12 is formed by an upper housing 16 and a lower housing 18. Figure 1 In the following description, the top is set as Figure 1 In the Z direction, set the front to Figure 1 In the X direction, set the right side to Figure 1 In the following description, the longitudinal direction refers to the left-right direction, the first orthogonal direction refers to the front-back direction, and the second orthogonal direction refers to the up-down direction. In addition, regarding multiple identical components, sometimes only some of the components are marked with reference numerals, and the reference numerals are omitted for the other components.

[0032] <Upper Housing 16>

[0033] The upper case 16 is made of synthetic resin and has a generally rectangular box shape that is open toward the lower case 18 (lower side). It includes a peripheral wall 20 that extends cylindrically from the peripheral edge of the upper surface toward the lower case 18. A plurality of mounting members 22 are mounted to the outer peripheral end of the upper case 16. The upper case 16 is mounted to an assembly target, such as a battery pack case (not shown), by bolts (not shown) inserted through the mounting members 22.

[0034] Two power relay mounting portions 24 are formed on the upper surface of the upper housing 16. Figure 2 As shown, power relays 26a and 26b are mounted on two power relay mounting portions 24 of the upper housing 16. The power relays 26a and 26b are formed into a substantially rectangular parallelepiped shape, for example, and have a plurality of bolt insertion portions 28 protruding to the left and right sides. Furthermore, the power relays 26a and 26b are fixed to the upper housing 16 by screwing bolts 30 inserted through the bolt insertion portions 28 of the power relays 26a and 26b into the upper housing 16. Figure 1 As shown, on the upper surface of the upper housing 16, two plate-shaped terminal support portions 32 are provided in front of the two power relay mounting portions 24. Figure 2As shown, upper terminal fittings 34 are mounted on the terminal support portion 32. Each upper terminal fitting 34 is formed from a conductive metal material and is formed into an L-shaped part with a flat-plate fixing portion 36 and a contact portion 38. The fixing portions 36 of the two sets of upper terminal fittings 34 overlap with the power relays 26a and 26b, and are fixed to the power relays 26a and 26b using bolts 40. This creates electrical continuity between the upper terminal fittings 34 and the power relays 26a and 26b. Two sets of upper terminal fittings 34 are connected to the power relays 26a and 26b at positions separated in the left-right direction.

[0035] A pre-charge relay mounting portion 42 is formed on the upper surface of the upper case 16. The pre-charge relay mounting portion 42 is formed in a rectangular cylindrical shape, and a pre-charge relay 44 constituting a pre-charge circuit is mounted from above the upper case 16.

[0036] <Lower Case 18>

[0037] The lower shell 18 is made of synthetic resin like the upper shell 16. Figure 1 As shown, it is formed into a generally rectangular flat plate shape. A plurality of bus bar mounting portions 46 are formed on the upper surface of the lower case 18. Each bus bar mounting portion 46 is formed to match the shape of each bus bar 48a to 48f, which will be described later, and is formed into a recessed groove shape so as to accommodate each bus bar 48a to 48f in a positioned state.

[0038] like Figure 1 、 Figure 3 、 Figure 4 As shown, the upper case 16 is overlapped with the lower case 18 from above, and the upper surface of the lower case 18 is covered by the upper case 16. Thus, the lower case 18 and the upper case 16 are combined with each other in the vertical direction to form the case 12 of the hollow box structure.

[0039] <Wiring Member 14>

[0040] The housing 12 houses the wiring member 14. The wiring member 14 is configured to include a plurality of bus bars 48a to 48f. Figure 1 As shown, bus bars 48a to 48f have various shapes. In this embodiment, a total of six bus bars 48a to 48f are used, and these bus bars 48a to 48f constitute wiring member 14. Bus bars 48a to 48f are manufactured by stamping and bending a metal flat plate into a predetermined shape.

[0041] The ends of busbars 48a to 48f are integrally formed with connection terminals 50 for external power supply. The connection terminals 50 of this embodiment are formed as bag-shaped female terminals that are connected in an inserted state by plate-shaped male terminals. Busbars 48a, 48b, 48e, and 48f are each provided with a connection terminal 50 at one end. A circular terminal 52 in the shape of an annular plate is provided at the other end of busbars 48a and 48b. A plate-shaped connector connection terminal 51 connected to a connector is provided at the other end of busbars 48e and 48f. In addition, busbars 48c and 48d are each provided with connection terminals 50 at both ends.

[0042] like Figure 1 and Figure 5 As shown, bus bars 48a to 48f are mounted on bus bar mounting portions 46 provided on the upper surface of lower case 18. Specifically, the flat intermediate portions of bus bars 48a to 48f extending horizontally (orthogonal to the vertical direction) are housed in a positioned state within bus bar mounting portions 46, thereby positioning bus bars 48a to 48f within lower case 18. In this manner, wiring member 14 including bus bars 48a to 48f is retained by lower case 18.

[0043] The round terminals 52 of bus bars 48a and 48b overlap with lower terminal fittings 54. Lower terminal fittings 54 are formed of a conductive metal material and are each formed into an L-shaped part having a flat plate-shaped fixing portion 56 and a contact portion 58. Furthermore, the round terminals 52 of bus bars 48a and 48b overlap with the fixing portions 56 of lower terminal fittings 54 from behind, making contact, and thus providing electrical continuity between the bus bars 48a and 48b and the lower terminal fittings 54.

[0044] The fixing portion 56 of the lower terminal fitting 54 penetrates the upper housing 16 and overlaps with the fixing portion 36 of the upper terminal fitting 34. This ensures that the lower terminal fitting 54 is electrically conductive to the upper terminal fitting 34 and the power relays 26a and 26b. Furthermore, the lower terminal fitting 54 electrically conductive to the bus bars 48a and 48b is connected to one power relay 26a, while the lower terminal fitting 54, which is separate and independent from the bus bars 48a to 48f, is electrically connected to the other power relay 26b. The contact portion 58 of the lower terminal fitting 54 overlaps with the lower surface of the terminal support portion 32 of the upper housing 16.

[0045] The terminals of the pre-charge relay 44, mounted on the pre-charge relay mounting portion 42 of the upper housing 16, are connected to the connection terminals 50 of the bus bars 48b, 48d, 48e, and 48f. This allows conduction between the bus bars 48b and 48f via the pre-charge relay 44. Furthermore, the connector connection terminals 51 of the bus bars 48e and 48f are connected to wiring connectors (not shown).

[0046] <Resistors 60a, 60b>

[0047] like Figures 1 to 5 As shown, resistors 60a and 60b serving as pre-charge resistors constituting a pre-charge circuit are mounted on the lower housing 18. Although the internal structure of the resistors 60a and 60b is omitted from the illustration, they have a structure in which a resistor body generating resistance and an insulating substrate supporting the resistor body are housed in a protective portion, and a pair of terminal portions 62 conducting to both ends of the resistor body protrude downward. As the resistor body, for example, a wound resistor body formed by winding a resistance wire of an alloy such as nickel-chromium (nickel-chromium alloy), copper-nickel, or copper-manganese-nickel around a bobbin can be used. The protective portion may be made of metal, but in this embodiment, it is made of ceramic. The outer shape of the resistors 60a and 60b is formed into a roughly rectangular parallelepiped, and the left and right directions ( Figure 2 The length of the left-right direction is greater than the front-back direction ( Figure 2 The length (width) of resistors 60a and 60b is defined as the vertical direction (in the vertical direction). Therefore, the left-right direction is the longitudinal direction of resistors 60a and 60b, and the front-back direction is the horizontal direction perpendicular to the longitudinal direction, i.e., the first perpendicular direction of resistors 60a and 60b. Circuit unit 10 includes two resistors 60a and 60b. However, these resistors 60a and 60b may be identical or have different resistance values, structures, materials, etc.

[0048] The resistors 60a and 60b each include a middle portion 64 where a resistor (not shown) is disposed between a pair of terminal portions 62 in the longitudinal direction, and two end portions 66 where the resistor is offset outward in the longitudinal direction. Figure 3 As shown, the upper surfaces of the two end portions 66 of the resistors 60a and 60b are located lower than the upper surface of the middle portion 64 of the resistors 60a and 60b, and steps 68 are formed on the upper surfaces of the resistors 60a and 60b at the boundaries between the middle portion 64 and the two end portions 66.

[0049] Resistors 60a and 60b, which constitute the precharge circuit, are subjected to a high voltage for a short period of time when power is applied. This causes the middle portion 64 of the wound resistor to generate a large amount of heat, reaching a high temperature. However, the end portions 66, which are located longitudinally outward from the pair of terminals 62, 62 connected to the resistor's ends, are offset from the resistor body and, therefore, do not reach the same high temperature as the middle portion 64 when power is applied. Furthermore, because resistors 60a and 60b are ceramic resistors with ceramic protective bodies, the thermal conductivity from the middle portion 64 to the end portions 66 is lower than that of metal resistors with metal protective bodies.

[0050] <Assembly of Resistors 60a, 60b>

[0051] like Figure 5As shown, the resistor 60a is mounted on a resistor support portion 70a that protrudes from the upper surface of the lower housing 18. The resistor support portion 70a is formed into a substantially square cylindrical shape. Figure 1 、 Figure 3 、 Figure 5 As shown, the positioning ribs 72 forming the outer portion in the longitudinal direction of the resistor support portion 70a protrude upward more than the lower support portion 74 forming the inner portion.

[0052] The positioning ribs 72 have an L-shaped cross-section and are arranged in pairs on opposite sides of the lower surface of the resistor 60a. The resistor support portion 70a of this embodiment has two positioning ribs 72 arranged continuously or closely together, forming a U-shaped cross-section overall. The positioning ribs 72 of the resistor support portion 70a overlap the outer surface of the lower portion of the resistor 60a in the longitudinal direction and the outer surface in the first orthogonal direction and are inserted into the lower corners 76 provided at the two end portions 66 of the resistor 60a. By inserting a pair of corners 76 located diagonally on the lower surface of the resistor 60a into the positioning ribs 72, the resistor 60a is horizontally positioned relative to the lower housing 18. In this embodiment, two pairs of positioning ribs 72 are provided, corresponding to the four corners 76 on the lower side of the resistor 60a, and all four corners 76 of the resistor 60a are inserted into the positioning ribs 72. This allows for more effective positioning of the resistor 60a relative to the lower housing 18.

[0053] The lower support portion 74 of the resistor support portion 70 a overlaps with the lower surface of the resistor 60 a and the resistor 60 a is supported by the lower support portion 74 of the resistor support portion 70 a , thereby positioning the resistor 60 a in the vertical direction relative to the lower case 18 .

[0054] like Figure 3 As shown, the terminal portion 62 of the resistor 60a attached to the lower case 18 is connected to the connection terminals 50 of the bus bars 48a and 48c arranged on the inner periphery of the resistor support portion 70a.

[0055] like Figure 5 As shown, resistor 60b is mounted on a resistor support portion 70b that protrudes from the upper surface of lower housing 18. Resistor support portion 70b is substantially identical to resistor support portion 70a, so a detailed description thereof will be omitted. Resistor 60b is positioned perpendicularly to lower housing 18 by inserting lower corners 76 of both end portions 66 into positioning ribs 72 of resistor support portion 70b. Furthermore, lower support portion 74 of resistor support portion 70b overlaps the lower surface of resistor 60b, thereby vertically positioning resistor 60b relative to lower housing 18.

[0056] like Figure 3As shown, the terminal portion 62 of the resistor 60b mounted on the lower case 18 is connected to the connection terminals 50 of the bus bars 48c and 48d arranged on the inner periphery of the resistor support portion 70b. Thus, the power relay 26a, the resistors 60a and 60b, and the pre-charge relay 44 are connected in series via the bus bars 48a to 48d.

[0057] <Bottom Gap 78>

[0058] Furthermore, the middle portions 64 of the resistors 60a and 60b do not contact any portion of the lower housing 18 other than the lower support portion 74 of the resistor support portions 70a and 70b, but are separated in a second orthogonal direction (the vertical direction) that is perpendicular to the longitudinal direction and the first orthogonal direction. Thus, in the second orthogonal direction, the separation distance between the middle portions 64 of the resistors 60a and 60b and the lower housing 18 is greater than the separation distance between the end portions 66 of the resistors 60a and 60b and the lower housing 18 (the lower support portion 74), at least in part. More specifically, the resistors 60a and 60b are separated from the lower housing 18 along the longitudinal direction of the resistor support portions 70a and 70a or the resistor support portions 70b and 70b that contact the resistors 60a and 60b. As a result, a lower gap 78 is formed between the middle portion 64 of the resistors 60a, 60b, which is away from the contact portion of the resistor supports 70a, 70b, and the lower case 18. This prevents heat from the middle portion 64 of the resistors 60a, 60b, which becomes hot when current is applied, from being transferred to the lower case 18.

[0059] Furthermore, the resistors 60a and 60b are positioned above the lower case 18, except for the corners 76 of the end portions 66 which are inserted into the positioning ribs 72 of the lower case 18. Therefore, the intermediate portions 64 of the resistors 60a and 60b are not covered by the lower case 18 in the first orthogonal direction (front-back direction).

[0060] <Window portions 80a, 80b>

[0061] Resistors 60a and 60b are exposed through windows 80a and 80b extending through upper housing 16. Windows 80a and 80b have rectangular cross-sections with the left-right direction being the longitudinal direction. Furthermore, by having upper housing 16 overlap lower housing 18 from above, the upper surfaces of longitudinally intermediate portions 64 of resistors 60a and 60b are exposed to the outside through windows 80a and 80b. Windows 80a and 80b have a widened portion 81 in the longitudinal middle, extending wider than the ends in a first orthogonal direction.

[0062] <Wall 82>

[0063] like Figure 3 、 Figure 4As shown, a cylindrical wall portion 82 is provided around the opening edges of the windows 80a and 80b in the upper case 16. The wall portion 82 protrudes upward and downward from the opening edges of the windows 80a and 80b, and the downwardly protruding portion is arranged so as to surround the upper ends of the resistors 60a and 60b.

[0064] <Pressing portion 84>

[0065] Pressing portions 84 are provided on both sides of the windows 80a and 80b in the longitudinal direction. These pressing portions 84 project from the upper end of the wall 82 toward the windows 80a and 80b. Furthermore, by contacting the upper surfaces of the longitudinal end portions 66 of the resistors 60a and 60b, the pressing portions 84 prevent the resistors 60a and 60b from falling upward through the windows 80a and 80b and thereby from being detached from the housing 12. Furthermore, by sandwiching the end portions 66 of the resistors 60a and 60b between the lower support portions 74 of the resistor support portions 70a and 70b and the pressing portions 84, the resistors 60a and 60b are supported by the housing 12.

[0066] <Side gap 86>

[0067] The windows 80a and 80b of the upper case 16 have a wide portion 81 in the middle of their longitudinal direction. In the first orthogonal direction, the distance between the middle portion 64 of the resistors 60a and 60b and the wall portion 82 of the upper case 16 is greater than the distance between the end portions 66 of the resistors 60a and 60b and the wall portion 82. Consequently, a lateral gap 86 is formed between the middle portion 64 of the resistors 60a and 60b and the wall portion 82 in the first orthogonal direction.

[0068] Thus, the middle portion 64 of the resistors 60a and 60b is further separated from the upper housing 16 in the first orthogonal direction than the end portions 66. Consequently, the heat from the middle portion 64 of the resistors 60a and 60b, which has reached a high temperature, is less likely to be transferred to the upper housing 16 through the side gaps 86, reducing the adverse effects of the heat generated by the resistors 60a and 60b on the upper housing 16. Furthermore, because the side gaps 86 are open to the outside of the upper housing 16, heat is less likely to be trapped in the side gaps 86, thereby improving heat dissipation performance.

[0069] Furthermore, windows 80a and 80b are formed in upper housing 16, through which the upper surfaces of intermediate portions 64 of resistors 60a and 60b are exposed to the outside. This prevents heat from intermediate portions 64 of resistors 60a and 60b from reaching upper housing 16 through the upper surfaces of intermediate portions 64, and also facilitates maintaining heat dissipation performance of resistors 60a and 60b.

[0070] In this manner, circuit unit 10 can suppress heat transfer from resistors 60a, 60b to upper case 16. This prevents adverse effects of heat from resistors 60a, 60b on upper case 16, even when upper case 16 is not formed of a heat-resistant material or when resistors 60a, 60b are enlarged to increase their heat capacity. Consequently, circuit unit 10 can be miniaturized and its weight reduced.

[0071] Furthermore, resistors 60a and 60b are supported between pressing portion 84 of upper case 16 and lower supporting portion 74 of lower case 18 at both end portions 66, where heat generation is relatively low compared to middle portion 64. This prevents adverse effects caused by heat transfer from resistors 60a and 60b to case 12 in middle portion 64, where heat generation is relatively low. Resistors 60a and 60b can be positioned relative to case 12 at both end portions 66, where temperature rise is relatively low.

[0072] By inserting the lower corners 76 of the resistors 60a and 60b into the positioning ribs 72 of the lower case 18, the resistors 60a and 60b are positioned horizontally relative to the case 12. Furthermore, steps 68 are provided on the upper surfaces of the resistors 60a and 60b, and the contact between the pressing portions 84 of the case 12 and the steps 68 also allows the resistors 60a and 60b and the case 12 to be positioned longitudinally.

[0073] Because the resistors 60a and 60b are ceramic resistors with protective bodies made of ceramic, heat generated in the middle portion 64 when current is passed through the resistors 60a and 60b is less likely to be transferred to the end portions 66. Therefore, even when the resistors 60a and 60b are mounted on the housing 12 at the end portions 66, the side gaps 86 and the lower gap 78 provided between the middle portion 64 and the housing 12 can suppress the heat from the resistors 60a and 60b from reaching the housing 12.

[0074] <Other Implementation Methods>

[0075] The technology described in this specification is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the technology described in this specification.

[0076] (1) In the above embodiment, the wall portion 82 of the upper case 16, which surrounds the resistors 60a and 60b in the horizontal direction, is separated from the middle portion 64 of the resistors 60a and 60b by a greater distance in the front-to-back direction than from the end portions 66 of the resistors 60a and 60b. However, for example, if the upper case 16 is configured to cover the upper sides of the resistors 60a and 60b, the wall portion of the upper case 16 can be formed as a portion covering the upper sides of the resistors 60a and 60b. In this case, the first orthogonal direction is the vertical direction, and the portion of the upper case 16 covering the upper sides of the resistors 60a and 60b is farther from the middle portion 64 of the resistors 60a and 60b in the vertical direction than from the end portions 66 of the resistors 60a and 60b. In the above embodiment in which the first orthogonal direction is the vertical direction, both the first orthogonal direction and the second orthogonal direction can be the vertical direction. In this way, the first orthogonal direction and the second orthogonal direction may be different directions or the same direction.

[0077] Alternatively, the first orthogonal direction may be a plurality of directions that are orthogonal to the longitudinal direction. Specifically, if the distance between the middle portion 64 and the upper housing 16 in the front-to-back direction and the vertical direction is greater than the distance between the end portions 66 and the upper housing 16 in the front-to-back direction and the vertical direction, respectively, the first orthogonal direction includes both the front-to-back direction and the vertical direction.

[0078] The second orthogonal direction in lower housing 18, like the first orthogonal direction, is not limited to the vertical direction shown in the above embodiment. Specifically, if lower housing 18 is positioned outside of resistors 60a and 60b in the front-to-back direction, the second orthogonal direction can be the front-to-back direction. In this case, both the first and second orthogonal directions can be the front-to-back direction, or, for example, the first orthogonal direction can be the vertical direction and the second orthogonal direction can be the front-to-back direction. Furthermore, similar to the first orthogonal direction, the second orthogonal direction can be multiple directions that are orthogonal to the longitudinal direction.

[0079] When the left-right direction is the longitudinal direction, the first and second orthogonal directions are not limited to the front-back direction and the up-down direction, but may be directions that are orthogonal to the longitudinal direction and inclined to the front-back direction and the up-down direction.

[0080] (2) The wall portion 82 of the upper case 16 surrounding the resistors 60a and 60b does not need to be limited to a cylindrical shape extending in the vertical direction. Specifically, for example, in the embodiment described above, when the cylindrical wall portion 82 is absent, the opening periphery of the window portions 80a and 80b in the upper case 16 can also be regarded as the wall portion.

[0081] (3) The widened portion (large width portion 81) in the first orthogonal direction of the wall portion 82 forming the side gap 86 can have its width dimension in the first orthogonal direction changed in stages relative to the portion deviating from the large width portion 81 as in the above-described embodiment, or can have its width dimension changed gradually.

[0082] (4) The middle portion 64 of the resistors 60a and 60b in the longitudinal direction is preferably spaced apart from the upper housing 16 as a whole in the first orthogonal direction. However, it is sufficient that at least a portion of the middle portion 64 is spaced apart from the upper housing 16, and it may be partially closer to the upper housing 16 than the end portions 66. Similarly, the middle portion 64 of the resistors 60a and 60b in the longitudinal direction is preferably spaced apart from the lower housing 18 as a whole in the second orthogonal direction. However, it is sufficient that at least a portion of the middle portion 64 is spaced apart from the lower housing 18, and it may be partially closer to the lower housing 18 than the end portions 66.

[0083] (5) In the above embodiment, the resistors 60a and 60b are mounted on the housing 12 by being sandwiched between the pressing portions 84 of the window portions 80a and 80b, respectively, provided on the upper housing 16, and the resistor supporting portions 70a and 70b of the lower housing 18. The structure for mounting the resistors 60a and 60b on the housing 12 is not particularly limited. Specifically, for example, claw-shaped portions that overlap with the upper surfaces of the end portions 66 of the resistors 60a and 60b may be provided on the mounting portions of the resistors 60a and 60b in the lower housing 18. In this way, the resistors 60a and 60b can be mounted on the lower housing 18 by being sandwiched between the upper surface of the lower housing 18 and the claw-shaped portions.

[0084] (6) In the above embodiment, a configuration in which two resistors 60a and 60b are connected in series has been described. However, the number of resistors may be one or three or more. Furthermore, the circuits constituting the circuit units may be modified as appropriate as long as they include resistors. For example, other components such as fuses and connectors may be included. The same effects as those in the above embodiment can be achieved in various circuit units.

[0085] (7) In the above embodiment, the middle portion 64 of the resistors 60a and 60b is located between the terminals 62 and 62. However, if the terminals 62 and 62 protrude closer to the center of the longitudinal direction than the ends of the resistor, for example, the middle portion 64 may be located outside the terminals 62 and 62 in the longitudinal direction. In short, the middle portion 64 is the portion of the resistor that becomes hot due to heat generated by the resistor when current is applied, and is not necessarily limited to being located between the terminals 62 and 62.

[0086] Description of Reference Numerals

[0087] 10 circuit units

[0088] 12 Housing

[0089] 14 Wiring components

[0090] 16 Upper shell

[0091] 18 lower shell

[0092] 20 surrounding walls

[0093] 22 Assembling components

[0094] 24 Power relay installation department

[0095] 26a, 26b power relays

[0096] 28 Bolt insertion part

[0097] 30 bolts

[0098] 32 Terminal support

[0099] 34 Upper terminal parts

[0100] 36 fixed part

[0101] 38 Contact Department

[0102] 40 bolts

[0103] 42 Pre-charge relay installation part

[0104] 44 Pre-charge relay

[0105] 46 Bus bar installation section

[0106] 48a~48f busbars

[0107] 50 connection terminals

[0108] 51 Connector terminal

[0109] 52 round terminals

[0110] 54 lower terminal parts

[0111] 56 fixed part

[0112] 58 Contact Department

[0113] 60a, 60b resistors

[0114] 62 Terminals

[0115] 64 middle part

[0116] 66 both ends

[0117] 68 steps

[0118] 70a, 70b resistor support portion

[0119] 72 positioning ribs

[0120] 74 lower support portion

[0121] 76 corner

[0122] 78 Gap below

[0123] 80a, 80b windows

[0124] 81 Wide Width

[0125] 82 Wall

[0126] 84 Pressing part

[0127] 86 Side Gap

Claims

1. A circuit unit, comprising: Wiring components; a lower housing for holding the wiring member; an upper shell covering the lower shell; as well as a resistor connected to the wiring member, The upper housing has a wall portion surrounding the resistor. In a first orthogonal direction perpendicular to the length direction of the resistor, a separation distance between a middle portion of the resistor in the length direction and the wall portion of the upper shell is greater than a separation distance between both end portions of the resistor in the length direction and the wall portion of the upper shell, The middle portion of the resistor is a portion located between a pair of terminal portions protruding toward the lower surface of the resistor in the longitudinal direction.

2. The circuit unit according to claim 1, wherein In a second orthogonal direction perpendicular to the longitudinal direction, a distance between the middle portion of the resistor and the lower case is greater than a distance between the end portions of the resistor and the lower case.

3. The circuit unit according to claim 1, wherein: The upper case has a pressing portion that contacts an upper surface of the resistor. The circuit unit according to claim 1 , wherein: The lower case has positioning ribs, and the both end portions of the resistor are inserted into the positioning ribs.

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