Circuit unit

Abstract

To disclose a circuit unit capable of suppressing a compression state of an elastic heat conduction member interposed between a heat-generating component and a heat dissipation target from being uneven, thereby suppressing deterioration of cooling performance caused by an increase in the partial thermal resistance of the elastic heat conduction member.SOLUTION: A circuit unit 10 includes a heat-generating component 22, a case 14, and a pressing component 16. The heat-generating component 22 has a thermal contact portion 154 that is thermal contact with a heat dissipation target 12 via an elastic heat-conducting member 68. The case 14 has an opening window 44 that exposes the thermal contact portion 154 to the outside, and an insertion hole 46 into which a fixed portion 34 provided on the heat dissipation target 12 is inserted. A pressing component 16 has a fixing portion 108 to be fixed to a fixed portion 34 of the heat dissipation target 12. In a state where a fixing portion 108 is fixed to the fixed portion 34 inserted into the insertion hole 46, the pressing component 16 contacts the heat-generating component 22, and the pressing component 16 fixed to the heat dissipation target 12 presses the heat-generating component 22 against the elastic heat-conducting member 68 without interposing the case 14 therebetween.SELECTED DRAWING: Figure 5

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 in a battery pack mounted on a vehicle and switches between energization and non-energization between a battery and a load. In the circuit unit, heat-generating components such as a relay and a pre-charge resistor that is a ceramic resistor are housed in a case. In order to promote heat dissipation of such heat-generating components, in the circuit unit of Patent Document 1, the heat contact portion of the heat-generating component fixed to the case is brought into contact with a metal outer casing that is a heat dissipation target via an elastic heat conduction sheet, thereby adopting a structure that secures a heat dissipation path for the heat-generating component.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the heat contact portion of the heat-generating component fixed to the case is brought into contact with the heat dissipation target via the elastic heat conduction sheet as in the structure of Patent Document 1, in the central portion of the heat-generating component that is separated from the fixing portion of the heat-generating component to the case, the elastic heat conduction sheet cannot be sufficiently compressed by the reaction force of the elastic heat conduction sheet. As a result, the thermal resistance increases in that portion, and there is a risk that the cooling performance deteriorates.

[0005] Therefore, a circuit unit is disclosed that can suppress the non-uniform compression state of the elastic heat conduction member interposed between the heat-generating component and the heat dissipation target, and suppress the deterioration of the cooling performance due to an increase in the partial thermal resistance of the elastic heat conduction member.

Means for Solving the Problems

[0006] The circuit unit of the present disclosure includes a heat generating component, a case for housing the heat generating component, and a pressing component for pressing the heat generating component. The heat generating component has a thermal contact portion that is thermally contacted with a heat dissipation target via an elastic heat conducting member, and an opposing surface that faces the thermal contact portion. The case has an opening window for exposing the thermal contact portion of the heat generating component to the outside, and an insertion hole into which a fixed portion provided on the heat dissipation target is inserted. The pressing component has a pressing surface that contacts the opposing surface of the heat generating component, and a fixing portion that is fixed to the fixed portion of the heat dissipation target. With the fixing portion fixed to the fixed portion inserted into the insertion hole, the pressing surface of the pressing component contacts the opposing surface of the heat generating component, and the pressing component fixed to the heat dissipation target presses the heat generating component against the elastic heat conducting member without passing through the case.

Advantages of the Invention

[0007] According to the circuit unit of the present disclosure, it is possible to suppress the non-uniformity of the compression state of the elastic heat conducting member interposed between the heat generating component and the heat dissipation target, and suppress the increase in the partial thermal resistance of the elastic heat conducting member.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying out the Invention

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. The circuit unit of the present disclosure (1) includes a heat-generating component, a case that houses the heat-generating component, and a pressing component that presses the heat-generating component. The heat-generating component has a thermal contact portion that is thermally in contact with the heat dissipation target via an elastic heat-conducting member, and an opposing surface that faces the thermal contact portion. The case has an opening window that exposes the thermal contact portion of the heat-generating component to the outside, and an insertion hole into which a fixed portion provided on the heat dissipation target is inserted. The pressing component has a pressing surface that contacts the opposing surface of the heat-generating component, and a fixing portion that is fixed to the fixed portion of the heat dissipation target. In a state where the fixing portion is fixed to the fixed portion inserted into the insertion hole, the pressing surface of the pressing component contacts the opposing surface of the heat-generating component, and the pressing component fixed to the heat dissipation target presses the heat-generating component against the elastic heat-conducting member without passing through the case.

[0010] According to the circuit unit of this aspect, the thermal contact portion of the heat-generating component housed in the case can be exposed from the opening window of the case and brought into contact with the heat dissipation target via the elastic heat conduction member. In this case, a pressing component separate from the heat-generating component and the case is adopted, and by fixing the fixing portion of the pressing component to the fixed portion of the heat dissipation target inserted into the insertion hole of the case, the pressing surface of the pressing component is brought into contact with the opposing surface of the heat-generating component, and the heat-generating component can be pressed against the elastic heat conduction member by the pressing surface of the pressing component directly fixed to the heat dissipation target without passing through the case. As a result, compared with the case of pressing the heat-generating component fixed to the case to the heat dissipation member side via the case as in the conventional structure, it is possible to suppress the non-uniform compression state of the elastic heat conduction member interposed between the heat-generating component and the heat dissipation target. As a result, it is possible to provide a circuit unit capable of suppressing the occurrence of an increase in partial thermal resistance of the elastic heat conduction member and the resulting deterioration of the cooling performance.

[0011] Note that the number of the fixing portion of the pressing component and the fixed portion of the heat dissipation target can be arbitrarily set according to the shape of the opposing surface of the heat-generating component. For example, when the opposing surface is annular, by providing one fixing portion at the center of the pressing component and fixing it to one fixed portion arranged at the opposing position, it is also possible to suppress the non-uniform compression state of the elastic heat conduction member. Further, when the opposing surface of the heat-generating component is circular, elliptical, rectangular, etc., a plurality of fixing portions arranged at a plurality of locations mutually separated in the circumferential direction are provided on the pressing component around the heat-generating component, and by fixing them to a plurality of fixed portions arranged at the locations opposing the plurality of fixing portions, it is possible to advantageously suppress the non-uniform compression state of the elastic heat conduction member.

[0012] (2) In the above (1), it is preferable that the pressing surface of the pressing component is in contact with the entire surface of the opposing surface of the heat-generating component. By the pressing surface of the pressing component pressing the entire surface of the opposing surface of the heat-generating component, the compression state of the elastic heat conduction member can be made even more uniform, and the occurrence of a non-uniform compression state and the resulting increase in partial thermal resistance and deterioration of the cooling performance can be more advantageously prevented.

[0013] (3) In the above (1) or (2), the pressing surface of the pressing component extends in a rectangular shape, the pressing component has the fixing portions provided on both end sides in the longitudinal direction of the pressing surface, and ribs protruding in the longitudinal direction are provided on the pressing component. This is preferable. Since the fixing portions of the pressing component are provided on both end sides in the longitudinal direction of the pressing surface, it becomes easy to evenly apply the pressing force by the pressing surface to the heat generating component. Moreover, since the pressing component is provided with ribs that extend in the longitudinal direction and spread between the fixing portions to which a fixing load for the heat dissipation target is applied, deformation of the pressing surface of the pressing component can be prevented, and the generation of an uneven compression state can be more advantageously suppressed.

[0014] (4) In any one of the above (1) to (3), the case has a holding portion that protrudes inside the case and engages with the heat generating component to hold the heat generating component in the case. The heat generating component has a mounting portion that is placed on the fixed portion to be fixed and fixed to the fixed portion together with the fixed portion. By fixing the mounting portion of the heat generating component to the fixed portion to be fixed, it is preferable that the heat generating component is separated from the holding portion. Since the case is provided with a holding portion that engages with the heat generating component to hold the heat generating component in the case, in the state before fixing the circuit unit to the heat dissipation target, the heat generating component can be advantageously prevented from detaching from the inside of the case through the opening window by engaging with the holding portion of the heat generating component. Also, in the state where the pressing component of the circuit unit is fixed to the fixed portion to be heat dissipated, by fixing the mounting portion of the heat generating component to the fixed portion together with the fixed portion, the heat generating component can be separated from the holding portion. Thereby, even when the case has a holding portion, a state can be realized in which the heat generating component is pressed against the heat dissipation target by the pressing component without passing through the case. As a result, it is possible to achieve both an improvement in the assembly workability of the circuit unit and the stability of the cooling performance.

[0015] (5) In the above (4), it is preferable that the holding portion includes a frame portion that surrounds the periphery of the opening window and protrudes inward of the case, and a held portion protruding from the peripheral wall portion of the heat generating component is placed on the protruding end surface of the frame portion. Since the holding portion includes a frame portion that surrounds the periphery of the opening window and protrudes into the case, interference between the heat generating component and other members can be prevented by the frame portion. Further, since the held portion protruding from the peripheral wall portion of the heat generating component is placed on the protruding end surface of the frame portion, the heat generating component can be reliably prevented from protruding from the opening window. Thereby, the heat generating component in the transport state or the like of the circuit unit before being fixed to the fixed portion to be cooled can be stably held in the case.

[0016] (6) In the above (5), it is preferable that the holding portion includes a bending piece portion that protrudes more inward of the case than the frame portion and is elastically deformable on the outer peripheral side of the opening window. The bending piece portion has a locking claw portion provided at the protruding tip and protruding to the inner peripheral side of the opening window. When the bending piece portion is elastically deformed to the outer peripheral side, the assembly of the heat generating component and the pressing component to the frame portion is allowed. In a state where the held portion of the heat generating component is placed on the protruding end surface of the frame portion, the locking claw portion of the elastically restored bending piece portion overlaps with the pressing component with a gap in the protruding direction of the frame portion. The holding portion further includes a bending piece portion in addition to the frame portion, and the locking claw portion provided at the protruding tip of the bending piece portion overlaps with the pressing component placed on the protruding end surface of the frame portion via the heat generating component with a gap in the protruding direction of the frame portion. Thereby, not only the protrusion of the heat generating component and the pressing component from the opening window but also the displacement in the opposite direction can be restricted by the engagement with the locking claw portion, and the heat generating component and the pressing component can be held more stably in the case.

[0017] (7) In the above (5) or (6), in a state of being fixed to the heat dissipation target, the fixed portion of the heat dissipation target is arranged inside the case beyond the protruding end surface of the frame portion in the protruding direction of the frame portion. It is preferable that the fixed portion of the heat dissipation target is arranged inside the case beyond the protruding end surface of the frame portion in the protruding direction of the frame portion. Thereby, by fixing the mounting portion of the heat generating component together with the fixing portion of the pressing component to the fixed portion, the heat generating component can be separated from the holding portion (frame portion), and the fixing portion of the heat generating component can be directly fixed to the fixed portion of the heat dissipation target.

[0018] (8) In any one of the above (1) to (7), the case has positioning bosses arranged at a plurality of locations around the opening window and protruding beyond the fixing portion, and the pressing component has a plurality of positioning holes penetrating at positions corresponding to the positioning bosses and through which the positioning bosses are inserted. It is preferable that by inserting the positioning boss into the positioning hole, the pressing component can be reliably guided to a predetermined assembly position. More preferably, for example, when it is necessary to distinguish the front and back of the pressing component, such as when ribs are provided on the pressing component as in the aspect of the above (3), by providing the positioning boss and the positioning hole at asymmetric positions on the pressing component, the effect of preventing misassembly of the front and back of the pressing component can also be obtained. Also, by making the shape of the pressing component, including not only the positioning boss and the positioning hole but also the fixing portion, a rotationally symmetric shape about the central axis, for example, it is not necessary to distinguish the front-back direction and / or the left-right direction of the pressing component, and the pressing component can be more easily positioned with respect to the case.

[0019] <Details of Embodiments of the Present Disclosure> A specific example of the circuit unit of the present disclosure will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0020] <Embodiment 1> Hereinafter, the circuit unit 10 of Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 9. This circuit unit 10 is mounted, for example, on an electric vehicle or a hybrid vehicle and is connected between an in-vehicle power supply (for example, a battery) not shown and a load (for example, an inverter) not shown. The circuit unit 10 includes a heat-generating component (in Embodiment 1, a pre-charge resistor 22 described later), and heat generated in the heat-generating component due to energization is dissipated through a heat dissipation target (a housing 12 described later) to which the circuit unit 10 is fixed. Note that the circuit unit 10 can be arranged in an arbitrary orientation in the vehicle. Hereinafter, the upper direction refers to the upper direction in FIG. 4, the lower direction refers to the lower direction in FIG. 4, the left direction refers to the left direction in FIG. 3, the right direction refers to the right direction in FIG. 3, the front direction refers to the lower direction in FIG. 3, and the rear direction refers to the upper direction in FIG. 3. Also, for a plurality of identical members, only some members may be labeled with reference numerals, and other members may be omitted from labeling.

[0021] <Circuit unit 10> The circuit unit 10 includes a heat-generating component, a case 14 that houses the heat-generating component, and a pressing component 16 that presses the heat-generating component. Note that the circuit unit 10 of Embodiment 1 includes a relay 18, a pre-charge relay 20, and a pre-charge resistor 22 as electrical components that generate heat when energized. In Embodiment 1, since the structure of the present disclosure is applied to the pre-charge resistor 22 among the above electrical components, the heat-generating component is constituted by the pre-charge resistor 22. And in Embodiment 1, not only the pre-charge resistor 22 but also the relay 18 and the pre-charge relay 20 are housed and held in the case 14.

[0022] <Heat dissipation target (housing 12)> The circuit unit 10 and the battery constituting the in-vehicle power supply can be housed, for example, in a metal housing 12. The circuit unit 10 and the battery are housed in the housing 12 to form a battery pack (not shown). That is, the circuit unit 10 is overlapped and fixed on the upper surface 24 of the housing 12, and heat generated when electricity is supplied to the electrical components provided in the circuit unit 10 is dissipated through the housing 12. Therefore, in Embodiment 1, the heat dissipation target for dissipating the heat generated in the circuit unit 10 is constituted by the metal housing 12. In the figure, a flat metal plate constituting the bottom wall portion of the housing 12 is shown. As shown in FIG. 1, for example, a refrigerant flow path 26 can be formed inside this metal plate. A known refrigerant is adopted for the refrigerant flowing through the refrigerant flow path 26. Also, the extending direction, length, etc. of the refrigerant flow path 26 shown in FIG. 1 are merely examples, and the extending direction, length, etc. of the refrigerant flow path are not limited.

[0023] Furthermore, as also shown in FIG. 6, on the upper surface 24 of the housing 12, support protrusions 28 for supporting the four corner portions of the circuit unit 10 protrude upward at four locations around the fixed position of the circuit unit 10. In the center of each support protrusion 28, a bolt fastening hole 32 for fastening a bolt 30 for fixing the circuit unit 10 is formed to open upward. Furthermore, on the upper surface 24 of the housing 12, at a predetermined location at the fixed position of the circuit unit 10, a fixed portion 34 to which a mounting portion 164 (to be described later) of a heat generating component (pre-charge resistor 22) is fixed protrudes upward.

[0024] In Embodiment 1, a pair of fixed parts 34a, 34a face each other with a predetermined distance therebetween in the front-rear direction, and another pair of fixed parts 34b, 34b face each other with a predetermined distance therebetween in the left-right direction. In the housing 12, a total of four fixed parts 34a, 34b are provided. In particular, in Embodiment 1, each fixed part 34b is provided at the center in the front-rear direction of each fixed part 34a, and each fixed part 34a is provided at the center in the left-right direction of each fixed part 34b. That is, the fixed parts 34a, 34b are arranged at positions that are rotationally symmetric about a central axis extending in the vertical direction with respect to the centers of the fixed parts 34a, 34b. These fixed parts 34a, 34b are generally prismatic in shape. As shown in FIG. 5, each fixed part 34a has a protruding dimension B from the upper surface 24 of the housing 12, and each fixed part 34b has a protruding dimension B' that is slightly larger than the protruding dimension B. At the upper end portions of the fixed parts 34a, 34b, screw fastening holes 38 for fastening screws 36 for fixing the mounting parts 164 and the fixed parts 34a, 34b are formed.

[0025] <Case 14> As described above, the circuit unit 10 has a case 14 that holds a relay 18 (positive and negative relays 18a, 18b described later), a precharge relay 20, and a precharge resistor 22. In Embodiment 1, the case 14 is generally a hollow rectangular parallelepiped shape, and the left-right dimension is larger than the front-rear dimension. In particular, in Embodiment 1, the case 14 includes an upper case 40 and a lower case 42 that can be assembled and disassembled with each other in the vertical direction. These upper case 40 and lower case 42 are formed of, for example, a synthetic resin. The fixing method of the upper case 40 and the lower case 42 is not limited. In Embodiment 1, in a state where the upper case 40 and the lower case 42 are overlapped, the bolts 30 described above are inserted at the four corners of the circuit unit 10 and fastened to bolt fastening holes 32 provided in the support protrusions 28 of the housing 12, so that the upper case 40 and the lower case 42 are fixed to each other.

[0026] In addition, the case 14 has an opening window 44 that exposes an after-mentioned thermal contact portion 154 of the heat-generating component (pre-charge resistor 22) to the outside, and insertion holes 46 into which respective fixed portions 34a, 34b provided on the object to be cooled (housing 12) are inserted. These opening window 44 and respective insertion holes 46 are all provided in the lower case 42. In Embodiment 1, since four fixed portions 34a, 34b are provided, four insertion holes 46a, 46b corresponding to the respective fixed portions 34a, 34b are formed in the lower case 42. That is, a pair of insertion holes 46a, 46a corresponding to each fixed portion 34a are provided at a predetermined distance in the front-rear direction, and another pair of insertion holes 46b, 46b corresponding to each fixed portion 34b are provided at a predetermined distance in the left-right direction. In short, the respective insertion holes 46a, 46b are also arranged at positions that are rotationally symmetric about a central axis extending in the vertical direction with respect to the centers of the respective insertion holes 46a, 46b.

[0027] <Upper case 40> The upper case 40 has a substantially box shape that opens downward as a whole, and includes an upper bottom wall portion 48 and an upper peripheral wall portion 50 that protrudes downward from the outer peripheral edge portion of the upper bottom wall portion 48. In the upper bottom wall portion 48, at positions corresponding to respective connection portions 122a - 122d of first to fourth power supply bus bars 118a - 118d, which will be described later, in a state where the circuit unit 10 is assembled, rectangular through-holes 52a - 52d that penetrate in the thickness direction (vertical direction) are provided. At the four corners around the upper case 40, mounting portions 56 having bolt insertion holes 54 are provided, and each mounting portion 56 is located somewhat above the lower end of the upper peripheral wall portion 50. Further, in the upper bottom wall portion 48, at positions corresponding to the respective insertion holes 46a, 46b of the lower case 42 in a state where the circuit unit 10 is assembled, circular insertion holes 58 that penetrate in the thickness direction are provided, and the respective screws 36 are fastened to bolt fastening holes 32 in the respective fixed portions 34a, 34b from above through the respective insertion holes 58.

[0028] <Lower case 42> As shown in FIG. 7 and the like, the lower case 42 has a bottom wall portion 60 that is flat as a whole, and the bottom wall portion 60 has substantially the same rectangular shape as the upper case 40 in plan view. Thus, when the upper case 40 and the lower case 42 are overlapped and fixed, the lower opening of the upper case 40 is covered by the bottom wall portion 60 of the lower case 42.

[0029] In the bottom wall portion 60, at positions corresponding to the respective heat radiation portions 130 of the first to fourth heat radiation bus bars 128a to 128d, which will be described later, in a state where the circuit unit 10 is assembled, rectangular opening windows 62 penetrating in the thickness direction (vertical direction) are provided respectively. Also, in the bottom wall portion 60, at a position corresponding to a heat contact portion 154 (lower wall portion 152 of the metal case 146) in the precharge resistor 22 (metal clad resistor) in a state where the circuit unit 10 is assembled, the above-described opening window 44 penetrating in the thickness direction (vertical direction) is provided. In Embodiment 1, the opening window 44 has a rectangular shape and has a larger area than a lower surface 156, which will be described later, of the precharge resistor 22 in plan view. Thus, the opening window 44 exposes the heat contact portion 154 (lower wall portion 152) of the metal case 146 so as to be thermally contactable with the housing 12 in a state where the circuit unit 10 is assembled.

[0030] Also, on both front and rear sides and both left and right sides of the opening window 44 in the longitudinal direction, the above-described insertion holes 46a and 46b into which the respective fixed portions 34a and 34b of the housing 12 are inserted are formed. These insertion holes 46a and 46b each have a substantially rectangular shape. In Embodiment 1, the opening window 44 communicates with the insertion holes 46a on both front and rear sides, and the insertion holes 46a are formed by being connected on both front and rear sides of the inner peripheral surface of the opening window 44. Also, the opening window 44 and the insertion holes 46b on both left and right sides are formed independently of each other, and the insertion holes 46b are formed at a predetermined distance from the opening window 44 in the lateral direction.

[0031] In Embodiment 1, in a state where the circuit unit 10 is fixed to the housing 12, an insulating sheet 64 and an elastic heat conductive member 66 are accommodated in a laminated state in each opening window 62 provided below each heat dissipation portion 130. Thereby, with respect to the housing 12 where each heat dissipation portion 130 in the first to fourth heat dissipation bus bars 128a to 128d is superposed on the bottom wall portion 60, it is in electrical insulation and thermally conductive contact. Note that the insulating sheet 64 and the elastic heat conductive member 66 do not necessarily have to be separate members, and may be composed of one member having insulating properties and heat conductivity. These insulating sheet 64 and elastic heat conductive member 66 are fixed (for example, adhered) to the lower surface of each heat dissipation portion 130 when fixing the circuit unit 10 to the housing 12, and as shown in FIG. 4, when the circuit unit 10 is fixed to the housing 12, each insulating sheet 64 and each elastic heat conductive member 66 are arranged in an accommodated state inside each opening window 62. Note that known ones can be adopted as the insulating sheet 64 and the elastic heat conductive member 66, and in particular, as the elastic heat conductive member 66, for example, a heat conductive sheet or a gap filler having good heat conductivity can be adopted.

[0032] Also, in a state where the circuit unit 10 is fixed to the housing 12, an elastic heat conductive member 68 is accommodated in an opening window 44 provided below a thermal contact portion 154 in the precharge resistor 22. As a result, the thermal contact portion 154 is in contact with the housing 12 in a thermally conductive state. Since the winding resistor constituting the precharge resistor 22 is accommodated in a metal case 146 (to be described later) in an insulated state, even when the circuit unit 10 is energized, the metal case 146 is in an electrically insulated state, and an insulating sheet 64 does not have to be disposed in the opening window 44. This elastic heat conductive member 68 is fixed (e.g., adhered) to the lower surface 156 of the thermal contact portion 154 (the lower wall portion 152 of the metal case 146), for example, when the circuit unit 10 is fixed to the housing 12. When the circuit unit 10 is fixed to the housing 12, the elastic heat conductive member 68 is arranged in a housed state inside the opening window 44. Note that, as the elastic heat conductive member 68, a member having the same material as the elastic heat conductive member 66 provided below the relay 18 (the positive and negative side relays 18a and 18b to be described later) can be adopted. Note that each of these elastic heat conductive members 66 and 68 may be in a rectangular sheet shape in an initial shape, or the initial shape may be in a gel or grease shape and hardened into a sheet shape by applying heat or light.

[0033] Furthermore, at the four corners around the lower case 42 (the bottom wall portion 60), mounting portions 72 having bolt insertion holes 70 are provided, and each mounting portion 72 is located somewhat above other portions in the bottom wall portion 60. In other words, at the four corners around the lower surface 74 of the lower case 42, recesses that are concave upward with respect to other portions are formed. In this way, on the outer peripheral portions of the upper case 40 and the lower case 42, corresponding concave and convex shapes are provided by forming the mounting portions 56 and 72 at the four corners around the periphery. As a result, when the upper case 40 and the lower case 42 are overlapped in the vertical direction, these concave and convex shapes are fitted to position the upper case 40 and the lower case 42 horizontally with respect to each other.

[0034] <Holding portion 76> Case 14 is provided so as to protrude inside case 14 and has a holding portion 76 that engages with a heat-generating component (precharge resistor 22) to hold the precharge resistor 22 inside case 14. In Embodiment 1, the lower case 42 has the holding portion 76, and the holding portion 76 protrudes upward toward the inner side of case 14. Further, the holding portion 76 includes a frame portion 78 that surrounds the periphery of the opening window 44 and protrudes upward toward the inner side of case 14. That is, the protruding direction of the frame portion 78 is the vertical direction (specifically, the direction from below to above). Specifically, the frame portion 78 has a pair of side wall portions 80, 80 that extend in the front-rear direction at both side edges in the left-right direction of the opening window 44, and each of these side wall portions 80 has a front-rear dimension larger than that of the opening window 44. Both end portions in the front-rear direction of each side wall portion 80 are bent in a crank shape, and both end portions in the front-rear direction of each side wall portion 80 are located inward in the left-right direction from the middle portion in the front-rear direction via the bent portions 82. Both end portions in the front-rear direction of each of these side wall portions 80 are support portions 84 on which each flange-like portion 158 in a metal case 146 of the precharge resistor 22 described later is placed and supported.

[0035] Each support portion 84 is located outward in the front-rear direction from the opening window 44. In Embodiment 1, since each insertion hole 46a is formed at both ends in the front-rear direction of the opening window 44, each support portion 84 is provided on both sides in the left-right direction of each insertion hole 46a. In other words, at both ends in the front-rear direction of the frame portion 78, an insertion window portion 86 that penetrates in the front-rear direction is provided between the opposing sides of each support portion 84, and the inside and outside of the frame portion 78 are communicated with each other by each insertion window portion 86. In Embodiment 1, two electric wires 136, 138 described later extend from the front end portion of the precharge resistor 22. When the precharge resistor 22 is held by the frame portion 78 (holding portion 76), each electric wire 136, 138 extends to the outside through the front insertion window portion 86. However, depending on the wiring pattern of the precharge circuit 132 described later, each electric wire 136, 138 may extend to the outside through the rear insertion window portion 86.

[0036] More specifically, at both front and rear ends in the longitudinal direction on the protruding end surface (upper end surface) 88 of the frame body portion 78, that is, with respect to the protruding end surface 88 of each support portion 84, each flange-like portion 158 (particularly, the held portions 166 which are both left and right end portions in the lateral direction) in the metal case 146 described later is placed. That is, each flange-like portion 158 of the metal case 146 in the precharge resistor 22 is placed as a mode of engagement with respect to each support portion 84 in the holding portion 76, whereby the precharge resistor 22 is held by the holding portion 76. In this state, the peripheral wall portion 148 in the metal case 146 described later is accommodated between the respective side wall portions 80 in the frame body portion 78.

[0037] Here, the upward protruding dimension (vertical dimension from the upper surface of the bottom wall portion 60 to the protruding end surface 88) A (see FIGS. 5 and 9) of the frame body portion 78 is made smaller than the upward protruding dimension (vertical dimension from the upper surface 24 of the housing 12 to the upper surfaces of the respective fixed portions 34a, 34b) B (see FIG. 5) of each fixed portion 34a, 34b provided on the housing 12. In particular, as will be described later, in the state where the circuit unit 10 is fixed to the housing 12, each fixed portion 34a, 34b protrudes into the interior of the circuit unit 10 through each insertion hole 46a, 46b of the lower case 42, and each fixed portion 34a, 34b is arranged inward (upward) of the case 14 beyond the protruding end surface 88 in the protruding direction (vertical direction) of the frame body portion 78. In short, in the state where the circuit unit 10 is fixed to the housing 12, the upper surfaces of the respective fixed portions 34a, 34b are positioned above the protruding end surface 88 of the frame body portion 78.

[0038] <Flexure piece portion 90> Also, the holding portion 76 protrudes upward inward of the case 14 from the frame body portion 78 and includes a flexure piece portion 90 that can be flexurally deformed (elastically deformed in Embodiment 1) on the outer peripheral side of the opening window 44. In Embodiment 1, the flexure piece portion 90 is provided at the intermediate portion in the longitudinal direction of each side wall portion 80. In particular, in Embodiment 1, a pair of flexure piece portions 90, 90 are provided spaced apart from each other in the longitudinal direction at the intermediate portion in the longitudinal direction of each side wall portion 80. Therefore, in Embodiment 1, a total of four flexure piece portions 90 are provided in the holding portion 76.

[0039] Each flexure piece portion 90 has a locking claw portion 92 provided at the protruding tip (upper end portion) and protruding inward in the left-right direction on the inner peripheral side of the opening window 44. In a state where the pre-charge resistor 22 and the pressing component 16 are assembled to the lower case 42, each locking claw portion 92 protrudes inward in the left-right direction to a position that overlaps the base plate portion 104 (to be described later) of the pressing component 16 in the vertical direction. In other words, in the projection in plan view in a state where the pre-charge resistor 22 and the pressing component 16 are assembled to the lower case 42, the protruding tips (inner ends in the left-right direction) of the respective locking claw portions 92 overlap the left and right side edges of the base plate portion 104. In Embodiment 1, the planar shapes of the pressing component 16 and the pre-charge resistor 22 are substantially equal, and the protruding tips of the respective locking claw portions 92 also overlap the pre-charge resistor 22 (the upper wall portion 150 of the metal case 146 to be described later) in the projection in plan view, but the present invention is not limited to this mode. That is, in the projection in plan view, the respective locking claw portions 92 and the pre-charge resistor 22 (upper wall portion 150) may not overlap.

[0040] And, on the upper surface of each locking claw portion 92, an inclined surface 94 is provided which inclines gradually downward as it goes inward in the left-right direction. As a result, when the precharge resistor 22 is assembled to the holding portion 76, the precharge resistor 22 is brought close to the holding portion 76 from above, so that both side edges in the left-right direction of the lower surface 156 of the metal case 146 described later come into contact with the inclined surfaces 94 of the respective locking claw portions 92, elastically deforming each flexible piece portion 90 outward in the left-right direction. Thereby, the assembly of the precharge resistor 22 to the frame portion 78 is permitted. Also, from above the precharge resistor 22, a pressing component 16 is assembled to the holding portion 76 (frame portion 78) in the same manner as the precharge resistor 22. In a state where each flange-shaped portion 158 of the metal case 146 is placed on the protruding end surface 88 of each support portion 84 and the pressing component 16 is superposed and arranged on the precharge resistor 22, each flexible piece portion 90 elastically returns (elastic recovery), so that, as also shown in FIG. 9 and the like, the locking claw portions 92 of each flexible piece portion 90 overlap with the pressing component 16 with a gap 96 therebetween in the protruding direction (vertical direction) of the frame portion 78.

[0041] <Positioning boss 98> Case 14 is provided with a plurality of pre-charge resistors 22 disposed at a plurality of locations around an opening window 44 where the pre-charge resistors 22 are oppositely arranged, and has positioning bosses 98 that project beyond a fixing part 108, which will be described later, in the pressing component 16. In Embodiment 1, the positioning bosses 98 are provided on the lower case 42, and as shown in FIG. 7 and the like, they are provided adjacent to the outside in the left-right direction with respect to a pair of side wall parts 80, 80 that face each other in the left-right direction. That is, in Embodiment 1, a pair of positioning bosses 98, 98 are provided in the lower case 42. One (right) positioning boss 98 is provided behind the right insertion hole 46b, and the other (left) positioning boss 98 is provided in front of the left insertion hole 46b. In particular, in Embodiment 1, since the respective insertion holes 46a, 46b are provided on both the front-rear sides and the left-right sides of the opening window 44, these respective insertion holes 46a, 46b and the respective positioning bosses 98 are formed at positions rotationally symmetric about a central axis extending in the vertical direction through the center of the opening window 44 (the intersection of the diagonals of the rectangular opening window 44) in a plan view.

[0042] More specifically, each positioning boss 98 includes a base part 100 having a substantially rectangular parallelepiped outer shape and a pin-shaped part 102 that projects upward from the central part of the base part 100 on the upper end surface of the base part 100. Both the respective base parts 100 and the respective pin-shaped parts 102 have a predetermined vertical dimension, and in a state where the pressing component 16 is assembled to the case 14 (lower case 42), the protruding tip (upper end part) of each pin-shaped part 102 is located above a fixing part 108, which will be described later, in the pressing component 16.

[0043] <Pressing component 16> As shown in FIGS. 5, 6, etc., the pressing component 16 is generally rectangular plate-shaped as a whole and is formed of a metal with relatively high deformation rigidity in Embodiment 1. That is, the pressing component 16 includes a base plate portion 104 that is substantially rectangular in plan view. When the pressing component 16 is assembled to the lower case 42, the pressing component 16 (base plate portion 104) extends in the front-rear direction. This pressing component 16 is overlapped with the heat-generating component (pre-charge resistor 22) from above to press the pre-charge resistor 22, and the lower surface of the pressing component 16 (base plate portion 104) is a pressing surface 106 that contacts the upper surface (opposing surface 157 described later) of the pre-charge resistor 22. In short, the pressing surface 106 extends substantially rectangularly in plan view.

[0044] This base plate portion 104 has predetermined front-rear direction dimensions and left-right direction dimensions, and the longitudinal direction is the front-rear direction. Specifically, the base plate portion 104 has front-rear direction dimensions and left-right direction dimensions that are substantially equal to the upper wall portion 150 (described later) of the pre-charge resistor 22. That is, in Embodiment 1, the entire lower surface of the base plate portion 104 is the pressing surface 106 that contacts the opposing surface 157 of the pre-charge resistor 22, and the pressing surface 106 is in contact with the entire opposing surface 157.

[0045] Both end portions in the front-rear direction of the base plate portion 104 are overlapped from above with each support portion 84 at both end portions in the front-rear direction of each side wall portion 80 and each insertion hole 46a on both sides in the front-rear direction when the pressing component 16 is assembled to the lower case 42. Thread insertion holes 107 that penetrate in the plate thickness direction (front-rear direction) are formed at both end portions in the front-rear direction of the base plate portion 104, and both end portions in the front-rear direction of the base plate portion 104 are fixed to each fixed portion 34a on both sides in the front-rear direction of the housing 12 by screws 36 inserted into each thread insertion hole 107. Therefore, both end side portions in the front-rear direction of the base plate portion 104 (pressing surface 106) (particularly, portions around each thread insertion hole 107) are fixed portions 108 that are fixed to each fixed portion 34a.

[0046] In addition, a pair of outward projecting portions 110, 110 projecting outward in the left - right direction are provided at the center portion in the front - rear direction of the base plate portion 104. Each of these outward projecting portions 110 has the same shape as each other and has a predetermined front - rear dimension and a left - right dimension. Specifically, in a plan view of the state where the pressing component 16 is assembled to the lower case 42, each outward projecting portion 110 overlaps with each insertion hole 46b and each positioning boss 98 provided on both left - right sides of the lower case 42. And at the center portion in the front - rear direction of each outward projecting portion 110, a screw insertion hole 107 is formed at a position corresponding to the screw fastening hole 38 in each fixed portion 34b. Further, at the end portion in the front - rear direction of each outward projecting portion 110, at a position corresponding to the pin - shaped portion 102 of each positioning boss 98, a positioning hole 112 through which each pin - shaped portion 102 is inserted is formed through each outward projecting portion 110.

[0047] As will be described later, in the state where the circuit unit 10 is fixed to the housing 12, the left - right end portions (each outward projecting portion 110) of the base plate portion 104 are fixed to the fixed portions 34b on both left - right sides of the housing 12 by screws 36 inserted into the screw insertion holes 107 in each outward projecting portion 110. Therefore, a fixing portion 108 that is also fixed to each fixed portion 34b is constituted by each outward projecting portion 110 (particularly, the portion around each screw insertion hole 107).

[0048] These outward projecting portions 110 are formed so as to be positioned between the front - rear directions of the respective flexure piece portions 90 in the holding portion 76 in the state where the pressing component 16 is assembled to the lower case 42, so that the outward projecting portions 110 and the flexure piece portions 90 do not interfere with each other when the pressing component 16 is assembled to the lower case 42.

[0049] Furthermore, in Embodiment 1, on the surface (upper surface) of the base plate portion 104 opposite to the pressing surface 106, ribs 114 extending in the longitudinal direction (front-rear direction) of the pressing component 16 are provided so as to protrude upward. These ribs 114 extend between the front and rear directions of the respective fixing portions 108, 108 with a predetermined front-rear dimension at the center in the left-right direction of the pressing component 16. By providing such ribs 114, even when the pressing component 16 is fixed to the respective fixed portions 34a, 34b in the housing 12 by the respective screws 36 as will be described later, deformation of the pressing component 16 can be suppressed.

[0050] Note that the pressing component 16 has a rotationally symmetric shape around a central axis extending in the vertical direction at the center of the base plate portion 104 (the intersection of the diagonals of the rectangular base plate portion 104), and can be assembled to the lower case 42 even in a state where it is rotated 180 degrees around the central axis as in the pressing component 16 shown in FIG. 3, for example. On the other hand, the pressing component 16 has a shape that is not line-symmetric with respect to a straight line L1 extending in the front-rear direction at the center in the left-right direction or a straight line L2 extending in the left-right direction at the center in the front-rear direction. As a result, the pressing component 16 shown in FIG. 3 cannot be assembled to the lower case 42 with the front and back (up and down) reversed. Therefore, by forming the pressing component 16 into the above-described shape, it is possible to surely prevent misassembly in the front-back reversed state, eliminate the need for identification in the front-rear direction and the left-right direction, and make it easier to assemble the pressing component 16 to the lower case 42.

[0051] <Relay 18> In Embodiment 1, in the circuit unit 10, a pair of relays 18, 18 are provided and arranged to be spaced apart from each other in the left-right direction. One of the relays (the right side in Embodiment 1) is the positive electrode side relay 18a, and the other relay (the left side in Embodiment 1) is the negative electrode side relay 18b. These positive electrode side and negative electrode side relays 18a, 18b each have a pair of terminal portions 116, 116 (one is shown in FIG. 4) spaced apart from each other in the left-right direction on the front side (the positive electrode side relay 18a is in the front, and the negative electrode side relay 18b is in the rear), and each terminal portion 116 is exposed on the surface of each relay 18a, 18b.

[0052] Each terminal portion 116 is an input and output terminal portion for each relay 18a, 18b. For example, in the positive electrode side relay 18a, the left terminal portion 116 is the input terminal portion on the positive electrode side, and the right terminal portion 116 is the output terminal portion on the positive electrode side. Also, in the negative electrode side relay 18b, the left terminal portion 116 is the output terminal portion on the negative electrode side, and the right terminal portion 116 is the input terminal portion on the negative electrode side.

[0053] The bus bars 118 for energization are overlapped with the respective terminal portions 116 of these relays 18a, 18b and fixed by bolts 120. That is, the circuit unit 10 includes first and second bus bars 118a, 118b for energization connected to the input and output terminal portions 116, 116 in the positive electrode side relay 18a, and third and fourth bus bars 118c, 118d for energization connected to the input and output terminal portions 116, 116 in the negative electrode side relay 18b. In a state where the circuit unit 10 is assembled, the end portions of the first to fourth bus bars 118a to 118d are exposed to the outside through through-holes 52a to 52d provided in the upper case 40 of the case 14, and input and output connection portions 122a, 122b on the positive electrode side and input and output connection portions 122c, 122d on the negative electrode side are respectively formed.

[0054] Then, the input connection portion 122a on the positive electrode side and the input connection portion 122c on the negative electrode side are electrically connected to the positive electrode side and negative electrode side terminal portions of a battery (not shown) by a conductive member made of a bus bar, an electric wire, or the like. Also, the output connection portion 122b on the positive electrode side and the output connection portion 122d on the negative electrode side are electrically connected to the positive electrode side and negative electrode side terminal portions of an inverter (not shown) by a conductive member. These connection portions 122a to 122d and the conductive member can be fixed by bolts 124 respectively.

[0055] As a result, a main circuit 126 between the battery and the inverter is constituted by including each relay 18a, 18b, first to fourth power supply bus bars 118a to 118d, and each of the above conduction members. And in this main circuit 126, by switching ON and OFF in each relay 18a, 18b, the energized state and the non-energized state in the main circuit 126 can be switched between the battery and the inverter.

[0056] In addition, in each terminal portion 116 of the positive electrode side and negative electrode side relays 18a, 18b, in addition to the first to fourth power supply bus bars 118a to 118d, first to fourth heat radiation bus bars 128a to 128d are respectively clamped together by each bolt 120. The first to fourth heat radiation bus bars 128a to 128d are each substantially L-shaped, and have a portion extending in the vertical direction and a portion that bends from the lower end portion of the portion extending in the vertical direction and spreads in the horizontal direction (a direction perpendicular to the vertical direction). Each of the heat radiation bus bars 128a to 128d is fixed to each terminal portion 116 in each relay 18a, 18b by each bolt 120 at their upper end portions, and their lower end portions extend in the front-rear direction and are located below each relay 18a, 18b.

[0057] A heat radiation portion 130 is constituted by a portion extending in the front-rear direction at the lower end portions of these heat radiation bus bars 128a to 128d. Each heat radiation portion 130 is in thermal contact with the housing 12 to be heat-radiated via the above-described insulating sheet 64 and elastic heat conductive member 66. By adopting such a structure, each terminal portion 116 of each relay 18a, 18b is in thermal contact with the housing 12 via each heat radiation bus bar 128a to 128d, the insulating sheet 64, and the elastic heat conductive member 66, and heat generated with the energization of each relay 18a, 18b can be radiated from the housing 12.

[0058] <Precharge circuit 132> A precharge circuit 132 is connected in parallel to the positive-side relay 18a in the main circuit 126. Specifically, in the precharge circuit 132, a precharge relay 20 and a precharge resistor 22 are connected in series. Then, the precharge relay 20 is electrically connected to the input terminal portion 116 of the positive-side relay 18a by an electric wire 134, and the precharge resistor 22 is electrically connected to the output terminal portion 116 of the positive-side relay 18a by an electric wire 136. Also, the precharge relay 20 and the precharge resistor 22 are electrically connected by an electric wire 138.

[0059] Terminals 140 are provided at at least one end of each of the electric wires 134, 136, and 138, and each terminal 140 is overlapped with each terminal portion 116 of the positive-side relay 18a or each terminal portion 144 (to be described later) of the precharge relay 20 and is fixed by a bolt 120 or a screw 142.

[0060] <Precharge relay 20> As the precharge relay 20, a known one can be adopted, and its structure is not limited, but it includes a pair of terminal portions 144, 144 (one is shown in FIG. 4) spaced apart from each other in the left-right direction. In Embodiment 1, the precharge relay 20 is arranged with the upper side as the front, and each terminal portion 144 is exposed on the upper surface of the precharge relay 20. Then, the terminal 140 provided at the end of the electric wire 134 connecting the positive-side relay 18a and the precharge relay 20 is overlapped with the input terminal portion 144 (the left terminal portion 144) of the precharge relay 20 and is fixed by a screw 142. Also, the terminal 140 provided at the end of the electric wire 138 connecting the precharge relay 20 and the precharge resistor 22 is overlapped with the output terminal portion 144 (the right terminal portion 144) of the precharge relay 20 and is fixed by a screw 142.

[0061] <Precharge resistor 22> The precharge resistor 22 is configured using a metal clad resistor. Since known ones can be adopted as the precharge resistor 22 (metal clad resistor), detailed description is omitted. A winding resistor (not shown) is enclosed in a metal case 146 in an insulated state. In sectional views such as Fig. 5, the illustration of the internal structure of the precharge resistor 22 is omitted, and only the metal case 146 is shown. In other words, the metal case 146 of the precharge resistor 22 has a hollow shape, and a winding resistor (not shown) is accommodated in an insulated state inside the metal case 146. In Embodiment 1, the metal case 146 of the precharge resistor 22 has a hollow substantially rectangular parallelepiped shape and is arranged in a direction extending in the front-rear direction. That is, the metal case 146 includes a substantially cylindrical peripheral wall portion 148 configured including wall portions on both sides in the front-rear direction and both sides in the left-right direction, an upper wall portion 150 covering the upper opening portion of the peripheral wall portion 148, and a lower wall portion 152 covering the lower opening portion of the peripheral wall portion 148.

[0062] The metal case 146 of this precharge resistor 22 (metal clad resistor) has a thermal contact portion 154 that is thermally in contact with the housing 12 as a heat dissipation target. In Embodiment 1, in the state where the circuit unit 10 described later is fixed to the housing 12, the metal case 146 is superposed on the housing 12 via an elastic heat conduction member 68 provided so as to be superposed on the lower surface (the lower surface of the lower wall portion 152) 156 of the precharge resistor 22, and the lower wall portion 152 constituting the hollow metal case 146 constitutes the thermal contact portion 154. And since the lower wall portion 152 of the metal case 146 constitutes the thermal contact portion 154, the opposing surface 157 opposing the thermal contact portion 154 in the metal case 146 is constituted by the upper surface (the upper surface of the upper wall portion 150) of the precharge resistor 22.

[0063] In particular, in Embodiment 1, at the upper end portion of the peripheral wall portion 148 (or the upper wall portion 150) in the metal case 146, flange-like portions 158 protruding on both sides in the front-rear direction are provided. Each of these flange-like portions 158 has a width direction (left-right direction) dimension substantially equal to that of the upper wall portion 150 (or the peripheral wall portion 148) and a predetermined protruding dimension (front-rear direction dimension). In the central portion in the left-right direction of each flange-like portion 158, a screw insertion groove 160 through which the aforementioned screw 36 for fixing the precharge resistor 22 is inserted is provided. By providing these flange-like portions 158, in the vertical projection, the upper surface (opposing surface) 157 of the precharge resistor 22 has a larger area than the lower surface 156 of the precharge resistor 22.

[0064] Also, as will be described later, each flange-like portion 158 is overlapped and placed on each fixed portion 34a in the housing 12, and each screw 36 is inserted into the screw insertion groove 160 and fastened to the screw fastening hole 38, so that the placement portion 164 in the heat-generating component (precharge resistor 22) is fixed to the fixed portion 34a. Therefore, the placement portion 164 is configured by the portion around the screw insertion groove 160 (the central portion in the left-right direction in each flange-like portion 158) in each flange-like portion 158. As described above, when the circuit unit 10 is fixed to the housing 12, the screw 36 is inserted into each screw insertion hole 107 in the pressing component 16 and fastened to each screw fastening hole 38. In short, by overlapping the pressing component 16 and the precharge resistor 22 (metal case 146), the each screw insertion hole 107 and each screw insertion groove 160 are communicated in the vertical direction. Then, by the screw 36 inserted into each of these screw insertion holes 107 and each screw insertion groove 160, each fixing portion 108 is fixed to each fixed portion 34a with each flange-like portion 158 (each placement portion 164) sandwiched therebetween. Therefore, each placement portion 164 in the precharge resistor 22 (metal case 146) is fixed to the fixed portion 34a together with each fixing portion 108 in the pressing component 16.

[0065] Furthermore, both left and right end portions in the horizontal direction of each flange-shaped portion 158 are placed on the holding portion 76 that protrudes into the case 14 (lower case 42), so that the heat-generating component (pre-charge resistor 22) is held within the case 14. Therefore, the held portion 166 is constituted by both left and right end portions in the horizontal direction of each flange-shaped portion 158. As a result, in Embodiment 1, both each placement portion 164 and each held portion 166 are provided on each flange-shaped portion 158, and in short, they are provided at the same position in the vertical direction.

[0066] As described above, the pre-charge resistor 22 is connected to the electric wire 136 connected to the positive electrode side relay 18a and the electric wire 138 connected to the pre-charge relay 20. Specifically, the electric wire 136 is connected to one end portion of the winding provided inside the pre-charge resistor 22, and the electric wire 138 is connected to the other end portion. And each of the electric wires 136 and 138 connected to both end portions of the winding extends from the inside to the outside of the metal case 146. In Embodiment 1, each of the electric wires 136 and 138 extends from one end portion (the front end portion in Embodiment 1) in the length direction of the metal case 146 to the outside. And each terminal 140 provided at the end portions of these electric wires 136 and 138 is overlapped with the output terminal portion 116 in the positive electrode side relay 18a and the output terminal portion 144 in the pre-charge relay 20, respectively, and is fixed by the bolt 120 and the screw 142, respectively.

[0067] <Assembly of Circuit Unit 10> Hereinafter, a specific example of the assembly method of the circuit unit 10 will be described. Note that the assembly method of the circuit unit 10 is not limited to the aspects described below.

[0068] First, the first to fourth power supply bus bars 118a to 118d and the first to fourth heat dissipation bus bars 128a to 128d are respectively overlapped with the terminal portions 116 of each relay 18a, 18b, and each is fixed by each bolt 120. At that time, the terminals 140 provided at the ends of the electric wires 134, 136 are also overlapped with the terminal portions 116 of the positive electrode side relay 18a, and each is tightened together by the bolt 120. Then, these relays 18a, 18b and the precharge relay 20 are placed on the lower case 42 and fixed by bolts or screws.

[0069] Also, the precharge resistor 22 is brought close to the holding portion 76 in the lower case 42 from above, and while elastically deforming each bending piece portion 90 outward in the left-right direction, it is assembled. By the locking claw portions 92 in each bending piece portion 90 getting over the upper wall portion 150 in the metal case 146, each bending piece portion 90 elastically restores and deforms. Thereby, each flange-shaped portion 158 in the metal case 146 is placed on the protruding end surface 88 of each support portion 84 in the holding portion 76, and each held portion 166 at both left and right ends in the left-right direction of each flange-shaped portion 158 is held by the holding portion 76.

[0070] Subsequently, in the same manner as the precharge resistor 22, the pressing component 16 is brought close to the holding portion 76 from above, and while elastically deforming each bending piece portion 90 outward in the left-right direction, it is assembled. At that time, by the pin-shaped portions 102 of the positioning bosses 98 in the lower case 42 being inserted into the positioning holes 112 in the pressing component 16, the pressing component 16 is assembled in a state of being positioned with respect to the lower case 42. By the locking claw portions 92 in each bending piece portion 90 getting over the base plate portion 104 in the pressing component 16, each bending piece portion 90 elastically restores and deforms. Thereby, the pressing surface 106, which is the lower surface of the pressing component 16, is overlapped with the upper surface (opposing surface 157) of the metal case 146. In particular, by the pin-shaped portions 102 being inserted into the positioning holes 112, the pressing component 16 is prevented from tilting with respect to the metal case 146, and the pressing surface 106 and the opposing surface 157 are overlapped with substantially no gap. Thereby, the metal case 146 is placed on the holding portion 76, and the pressing component 16 is placed on the metal case 146.

[0071] In this state, the inner ends in the left - right direction of each locking claw portion 92 overlap with the left - right direction both - side edge portions of the base plate portion 104 in the up - down direction. For example, even when the pre - charge resistor 22 and the pressing component 16 are displaced upward, the engagement between each locking claw portion 92 and the base plate portion 104 prevents the pre - charge resistor 22 and the pressing component 16 from coming out upward from the holding portion 76. In other words, in this state, the pre - charge resistor 22 and the pressing component 16 can be displaced in the up - down direction within each gap 96 between each locking claw portion 92 and the base plate portion 104 and are temporarily assembled to the lower case 42.

[0072] Next, with respect to the lower case 42 in which each relay 18a, 18b, the pre - charge relay 20, the pre - charge resistor 22, and the pressing component 16 are assembled as described above, the upper case 40 is brought close from above as shown in FIG. 8, and the upper case 40 and the lower case 42 are overlapped as shown in FIG. 9. As a result, each mounting portion 56 in the upper case 40 and each mounting portion 72 in the lower case 42 are overlapped, and as described above, the concavo - convex shapes of the outer peripheral portions of the upper case 40 and the lower case 42 are fitted. As a result, the horizontal displacement between the upper case 40 and the lower case 42 is prevented, and the circuit unit 10 of Embodiment 1 is completed. In the circuit unit 10 before being assembled to the housing 12, for example, by inserting bolts 30 into the bolt insertion holes 54, 70 at the four corners of the periphery, the upper case 40 and the lower case 42 may not be separated in the up - down direction.

[0073] <Assembly of the circuit unit 10 to the heat - dissipation target (housing 12)> Hereinafter, a specific example of a method for assembling the circuit unit 10 to the housing 12 which is the heat - dissipation target will be described. Note that the method for assembling the circuit unit 10 to the housing 12 is not limited to the mode described below.

[0074] First, the circuit unit 10 manufactured as described above is superposed on a predetermined position on the upper surface 24 of the housing 12. In FIGS. 2 and 3, for clarity, the upper case 40 is shown in a state separated from the lower case 42, but the circuit unit 10 is integrally assembled to the housing 12. At that time, each insulating sheet 64 and each elastic heat conductive member 66 are laminated and fixed to each heat dissipation part 130 in each of the heat dissipation bus bars 128a to 128d, and the elastic heat conductive member 68 is fixed to the lower wall part 152 of the precharge resistor 22 (metal case 146). Further, the circuit unit 10 is superposed on the upper surface 24 such that each support protrusion 28 protruding on the upper surface 24 fits into a recess formed due to the provision of the attachment part 72 on the lower surface of the circuit unit 10 (the lower surface 74 of the lower case 42). Thereby, the circuit unit 10 and the housing 12 are positioned in the horizontal direction, and the bolt insertion holes 54 and 70 at the four corners of the circuit unit 10 and the bolt fastening holes 32 in each support protrusion 28 are communicated in the vertical direction.

[0075] Then, by overlapping the circuit unit 10 on the upper surface 24 of the housing 12, the fixed parts 34a and 34b protruding upward from the upper surface 24 are inserted into the circuit unit 10 through the insertion holes 46a and 46b provided in the lower case 42. In particular, as described above, in a state where the lower surface of the circuit unit 10 (the lower surface 74 of the lower case 42) and the upper surface 24 of the housing 12 are overlapped, the upper surfaces of the fixed parts 34a protrude upward beyond the protruding end surfaces 88 of the frame parts 78. Thus, in a state where the lower surface 74 of the circuit unit 10 and the upper surface 24 of the housing 12 are overlapped, the upper surfaces of the fixed parts 34a abut against the flange-like parts 158 of the respective metal cases 146 from below, and these flange-like parts 158 (in particular, the held parts 166) are separated upward from the protruding end surfaces 88 of the holding parts 76 (in particular, the support parts 84). As a result, the screw insertion holes 107 in the fixing parts 108, the screw insertion grooves 160 in the flange-like parts 158, and the screw fastening holes 38 in the fixed parts 34a communicate with each other in the vertical direction. Further, the fixed parts 34b abut against the outward protruding parts 110 of the pressing parts 16 from below, and the screw insertion holes 107 in the outward protruding parts 110 and the screw fastening holes 38 in the fixed parts 34b communicate with each other in the vertical direction.

[0076] From such a state, bolts 30 are inserted into the bolt insertion holes 54 and 70 at the four corners of the circuit unit 10 and fastened to the bolt fastening holes 32. Further, through the insertion holes 58 in the upper case 40, screws 36 are inserted into the screw insertion holes 107 and the screw insertion grooves 160 and fastened to the screw fastening holes 38 to fix the fixing parts 108 constituted by the portions around the screw insertion holes 107 and the fixed parts 34a and 34b. In particular, as described above, the fixing parts 108 and the fixed parts 34a are fixed together with the mounting parts 164, that is, with the flange-like parts 158 (the mounting parts 164) interposed therebetween. Thereby, the assembly of the circuit unit 10 to the housing 12 is completed.

[0077] In a state where the circuit unit 10 is assembled to the housing 12, the pressing surface 106 of the pressing component 16 is in contact with the opposing surface 157 of the precharge resistor 22 (metal case 146) over substantially the entire surface. Then, by fixing each fixing portion 108 and each fixed portion 34a, 34b with the screw 36, the pressing component 16 is brought closer to the housing 12, and the precharge resistor 22 is pressed by this pressing component 16 without passing through the case 14 (lower case 42), that is, through the opening window 44 against the elastic heat conductive member 68 and the housing 12. Further, each heat radiating portion 130 of each of the heat radiating bus bars 128a to 128d is in thermal contact with the housing 12 via each insulating sheet 64 and each elastic heat conductive member 66, and the thermal contact portion 154 of the precharge resistor 22 is in thermal contact with the housing 12 via the elastic heat conductive member 68. In a state where the circuit unit 10 is assembled to the housing 12, it is preferable that these insulating sheets 64 and elastic heat conductive members 66, 68 are slightly compressed in the vertical direction between each heat radiating portion 130 or the thermal contact portion 154 (lower wall portion 152) and the housing 12.

[0078] As described above, in the circuit unit 10 assembled in the housing 12 of the battery pack, each of the connection portions 122a to 122d is electrically connected to the battery and the inverter by a conductive member (not shown). Thereby, the battery and the inverter are electrically connected via the circuit unit 10.

[0079] Here, generally, when the vehicle is started, electricity flows from the battery to the inverter to charge the capacitor in the inverter. However, the current (inrush current) at the time of such vehicle startup is relatively large. If the inrush current flows through the main circuit, there is a risk of damaging the main relay. A precharge resistor is provided for the purpose of preventing this damage. That is, when the vehicle is started, the positive-side relay 18a is turned OFF and the precharge relay 20 is turned ON, so that power is supplied from the battery to the capacitor in the inverter via the precharge circuit 132, thereby avoiding damage to the positive-side relay 18a and charging the capacitor. After the vehicle is started, the positive-side relay 18a is turned ON and the precharge relay 20 is turned OFF, so that power is supplied from the battery to the inverter through the main circuit 126. Therefore, when the precharge circuit 132 is energized at the time of vehicle startup, the precharge resistor 22 generates heat, and when the main circuit 126 is energized after the vehicle is started, the relays 18a and 18b generate heat. That is, the timing of heat generation of the precharge resistor 22 and the positive-side relay 18a is different.

[0080] On the other hand, the housing 12 with which the thermal contact portion 154 is in thermal contact is also in thermal contact with the positive-side relay 18a. Thereby, in the precharge resistor 22 and the positive-side relay 18a with different heat generation timings, a common heat dissipation path can be configured, and an increase in the number of components, etc., is avoided compared to the case where the precharge resistor 22 and the positive-side relay 18a form separate heat dissipation paths.

[0081] In the circuit unit 10 of Embodiment 1 having the above-described structure, a metal clad resistor capable of handling a large current is employed as the precharge resistor 22. That is, in the metal clad resistor, a wound resistor in an insulated state is housed in a metal case 146, and heat dissipation through the metal case 146 is possible. As a result, the metal clad resistor has better heat dissipation performance than, for example, a ceramic resistor. Even when multiple ceramic resistors are required, the metal clad resistor can handle a large current with a smaller number (for example, one). As a result, the mounting space for the precharge resistor can be reduced, and the circuit unit 10 can be made smaller.

[0082] Also, in the circuit unit 10, a pressing component 16 that presses a heat-generating component (precharge resistor 22) is employed. In a state where the circuit unit 10 is fixed to the housing 12, by fixing each fixing portion 108 provided on the pressing component 16 to each fixed portion 34a, 34b provided on the housing 12, a configuration is adopted in which the thermal contact portion 154 in the precharge resistor 22 is pressed substantially evenly in the circumferential direction with respect to the housing 12. Thereby, it is possible to avoid the problem that the elastic heat conduction member 68 located between the thermal contact portion 154 (lower wall portion 152) and the housing 12 is partially compressed in the circumferential direction and the heat dissipation efficiency deteriorates. By pressing the precharge resistor 22 and the elastic heat conduction member 68 substantially evenly over the entire pressing component 16, good heat dissipation performance can be exhibited.

[0083] In particular, the pressing surface 106 of the pressing component 16 is in contact with the entire opposing surface 157, which is the upper surface of the precharge resistor 22. Thereby, by fixing the pressing component 16 to the housing 12, the entire precharge resistor 22 can be pressed by the pressing component 16, that is, the entire elastic heat conduction member 68 can be pressed against the housing 12. As a result, the improvement in heat dissipation performance in the circuit unit 10 can be more reliably achieved.

[0084] The pressing component 16 is provided with the respective fixing portions 108 at both ends in the longitudinal direction (front-rear direction), and is provided with ribs 114 extending in the longitudinal direction. Thereby, even when each fixing portion 108 and each fixed portion 34a on both sides in the longitudinal direction are fixed by screws 36 as in the first embodiment, deformation of the pressing component 16 can be suppressed, and local compression in the elastic heat conduction member 68 can be avoided. As a result, further improvement in the heat dissipation performance of the circuit unit 10 can be achieved. In particular, in the first embodiment, the respective fixing portions 108 are also provided at both ends in the short-side direction (left-right direction) of the pressing component 16, and the respective fixing portions 108 are provided at substantially equal intervals in the circumferential direction of the pressing component 16. Thereby, the precharge resistor 22 and the elastic heat conduction member 68 can be pressed substantially evenly over the whole, and further improvement in the heat dissipation performance can be achieved.

[0085] Also, since the ribs 114 are provided on the pressing component 16, it is necessary to distinguish between the front and back (upper and lower) of the pressing component 16. However, by providing the respective positioning holes 112 (and the respective positioning bosses 98) at positions that are not line-symmetrical with respect to the straight line L1 or the straight line L2 as in the first embodiment, incorrect assembly in the state where the front and back of the pressing component 16 are reversed can be prevented. In particular, in the first embodiment, the pressing component 16 has a rotationally symmetric shape about a central axis extending in the vertical direction (a central axis extending in the vertical direction at the intersection of the straight line L1 and the straight line L2), and the pressing component 16 can be assembled to the lower case 42 without specifying one or the other of the front-rear direction or one or the other of the left-right direction in the pressing component 16. Further, the respective positioning bosses 98 and the respective positioning holes 112 are provided at corresponding positions, and when assembling the pressing component 16 to the lower case 42, the pressing component 16 and the lower case 42 can be positioned relative to each other.

[0086] And in the circuit unit 10, before being attached to the housing 12 to be cooled, the pre-charge resistor 22, which is a heat-generating component, was held by the holding portion 76 provided in the case 14 within the case 14. However, when being attached to the housing 12, the pre-charge resistor 22 is separated from the holding portion 76, and each mounting portion 164 of the pre-charge resistor 22 is directly fixed to each fixed portion 34a, 34b in the housing 12. Thereby, it is not necessary to consider the tolerance in the case 14, and the heat-conductive contact portion 154 of the pre-charge resistor 22 and the housing 12 can be more reliably brought into thermal contact with each other.

[0087] That is, for example, when the pre-charge resistor is fixed to the case as in the conventional structure and the case is fixed to the housing to bring the pre-charge resistor and the housing into thermal contact, it is necessary to consider the tolerance in the case, and accordingly, it is necessary to make the elastic heat-conductive member thick. In other words, by directly fixing the pre-charge resistor 22 and the housing 12 as in the first embodiment, it is not necessary to consider the tolerance in the case 14, and accordingly, the elastic heat-conductive member 68 can be made thin, and the heat conduction efficiency can be improved.

[0088] The holding portion 76 includes a frame portion 78 that surrounds the periphery of the opening window 44 and protrudes inward of the case 14. Before the circuit unit 10 is fixed to the housing 12, a held portion 166 (flange-like portion 158) that protrudes from the peripheral wall portion 148 of the pre-charge resistor 22 to the outer peripheral side is placed on the protruding end face 88 of the frame portion 78. Thereby, in the circuit unit 10, the extraction of the pre-charge resistor 22 through the opening window 44 can be prevented. In particular, in the first embodiment, the frame portion 78 includes a pair of side wall portions 80, 80 that face each other in the left-right direction. In a state where the pre-charge resistor 22 is held by the holding portion 76, the displacement of the pre-charge resistor 22 in the left-right direction is also suppressed. As a result, before the circuit unit 10 is fixed to the housing 12, the displacement of the pre-charge resistor 22 within the case 14 is suppressed, and damage to the pre-charge resistor 22 and the like can be prevented.

[0089] Furthermore, the holding portion 76 includes a flexible piece portion 90 having a locking claw portion 92 at the protruding tip. In a state where the pre-charge resistor 22 and the pressing component 16 are assembled to the holding portion 76, by the contact between each locking claw portion 92 and the base plate portion 104 of the pressing component 16, the pre-charge resistor 22 and the pressing component 16 are prevented from being pulled out upward from the holding portion 76. Therefore, before the circuit unit 10 is fixed to the housing 12, not only the displacement in the left-right direction is suppressed as described above, but also the upward displacement is suppressed. Thus, damage to the pre-charge resistor 22 can be more reliably prevented.

[0090] Each mounting portion 164 of the pre-charge resistor 22 is provided at the same position in the vertical direction as each held portion 166. Each fixed portion 34a, 34b in the housing 12 is arranged to be located more upward beyond the protruding end surface 88 of the frame portion 78 when the circuit unit 10 is fixed to the housing 12. In Embodiment 1, each mounting portion 164 and each held portion 166 of the pre-charge resistor 22 are both formed in each flange-shaped portion 158 of the metal case 146. For example, compared with the case where the fixing portion and the held portion are provided separately, the pre-charge resistor 22, and thus the circuit unit 10, can be manufactured with a simpler structure. Also, each fixed portion 34a, 34b protrudes upward from the upper surface 24 of the housing 12, and screw fastening holes 38 are provided at the upper end portions of each fixed portion 34a, 34b. Thereby, in the housing 12, the refrigerant flow path 26 can be formed without considering the positions of the screw fastening holes 38.

[0091] <Modification Example> As described above, as a specific example of the present disclosure, Embodiment 1 has been described in detail. However, the present disclosure is not limited by this specific description. Modifications, improvements, etc. within the scope that can achieve the object of the present disclosure are included in the present disclosure. For example, modification examples of the following embodiments are also included in the technical scope of the present disclosure.

[0092] (1) In the above embodiment, the heat dissipation target was the housing 12 of the battery pack, but it is not limited to this aspect. That is, the heat dissipation target may be any member that thermally contacts the heat-generating component when the circuit unit according to the present disclosure is mounted on the vehicle. For example, it may be a metal member constituting the vehicle body or the like. In addition, in the heat dissipation target, a refrigerant flow path as described in the above embodiment may not be provided.

[0093] (2) In the above embodiment, the heat-generating component was constituted by the pre-charge resistor 22, but it is not limited to this aspect. The heat-generating component employed in the circuit unit according to the present disclosure may be any component that generates heat upon energization. For example, it may be a relay, a fuse, a pre-charge relay, or the like.

[0094] (3) In the above embodiment, in the bottom wall portion 60 of the lower case 42, the opening window 44 and the respective insertion holes 46a on both sides in the front-rear direction were formed to communicate with each other, but the opening window and these insertion holes may be formed separately. In addition, the shapes, sizes, numbers, etc. of the opening window and the insertion holes are not limited. The shape, size, number, etc. of the opening window can be appropriately set according to the heat-generating component, and the shape, size, number, etc. of the insertion holes can be appropriately set according to the fixed portion provided on the heat dissipation target.

[0095] (4) In the above embodiment, the structure of the pre-charge resistor (metal clad resistor) constituting the heat-generating component is not limited as long as it has a metal case. In the above embodiment, the electric wires 136 and 138 extending from the pre-charge resistor 22 extended from one end (front end) in the length direction of the pre-charge resistor 22. However, for example, two electric wires may extend from both sides in the length direction of the pre-charge resistor.

[0096] (5) In the above-described embodiment, the rib 114 was provided on the upper surface of the pressing component 16. However, if the heat-generating component can be pressed substantially evenly by the pressing component, a rib may be provided on the lower surface of the pressing component. Such a rib is not essential. Further, in the above-described embodiment, each positioning hole 112 was provided at a position that is not line-symmetric with respect to the straight lines L1 and L2, but the present invention is not limited to this mode. That is, the pressing component may be assembled to the lower case in a state where the front and back (upper and lower) are reversed, thereby improving the manufacturing efficiency.

Explanation of Reference Numerals

[0097] 10 Circuit unit 12 Housing (object to be cooled) 14 Case 16 Pressing component 18 Relay 18a Positive-side relay 18b Negative-side relay 20 Precharge relay 22 Precharge resistor (heat-generating component) 24 Upper surface 26 Refrigerant flow path 28 Support protrusion 30 Bolt 32 Bolt fastening hole 34 Fixed part 34a Fixed part (opposing in the front-rear direction) 34b Fixed part (opposing in the left-right direction) 36 Screw 38 Screw fastening hole 40 Upper case 42 Lower case 44 Opening window 46 Insertion hole 46a Insertion hole (opposing in the front-rear direction) 46b Insertion hole (opposing in the left-right direction) 48 Upper bottom wall part 50 Upper peripheral wall part 52a~52d Through window 54 Bolt insertion hole 56 Mounting part 58 Insertion hole 60 Bottom wall portion 62 Opening window 64 Insulating sheet 66, 68 Elastic heat conductive member 70 Bolt insertion hole 72 Mounting portion 74 Bottom surface 76 Holding portion 78 Frame body portion 80 Side wall portion 82 Bending portion 84 Support portion 86 Insertion window portion 88 Protruding end face 90 Deflection piece portion 92 Lock claw portion 94 Inclined surface 96 Gap 98 Positioning boss 100 Base portion 102 Pin-shaped portion 104 Base plate portion 106 Pressing surface 107 Screw insertion hole 108 Fixing portion 110 Outer protruding portion 112 Positioning hole 114 Rib 116 Terminal portion 118 Bus bar for energization 118a~118d First~Fourth bus bars for energization 120 Bolt 122a~122d Connection portion 124 Bolt 126 Main circuit 128a~128d First~Fourth heat dissipation bus bars 130 Heat dissipation portion 132 Pre-charge circuit 134, 136, 138 Electric wire 140 Terminal 142 Screw 144 Terminal portion 146 Metal case 148 Peripheral wall portion 150 Upper wall portion 152 Lower wall portion 154 Thermal contact portion Below 156 Opposite surface (upper surface) 157 Flange-shaped portion 158 Thread insertion groove 160 Placement portion 164 Held portion 166 Straight lines L1, L2

Claims

1. A heat generating component, a case for housing the heat generating component, and a pressing component for pressing the heat generating component, wherein the heat generating component has a heat contact portion that is thermally in contact with a heat dissipation target via an elastic heat conductive member, and an opposing surface that faces the heat contact portion, the case has an opening window for exposing the heat contact portion of the heat generating component to the outside, and an insertion hole into which a fixed portion provided on the heat dissipation target is inserted, the pressing component has a pressing surface that contacts the opposing surface of the heat generating component, and a fixing portion that is fixed to the fixed portion of the heat dissipation target, in a state where the fixing portion is fixed to the fixed portion inserted into the insertion hole, the pressing surface of the pressing component contacts the opposing surface of the heat generating component, and the pressing component fixed to the heat dissipation target presses the heat generating component against the elastic heat conductive member without passing through the case. A circuit unit.

2. The circuit unit according to claim 1, wherein the pressing surface of the pressing component is in contact with the entire surface of the opposing surface of the heat generating component.

3. The pressing surface of the pressing component extends in a rectangular shape, the pressing component has the fixing portions provided on both end sides in the longitudinal direction of the pressing surface, and ribs extending in the longitudinal direction project from the pressing component. The circuit unit according to claim 1 or claim 2.

4. The case has a holding portion that projects inside the case and engages with the heat generating component to hold the heat generating component inside the case, the heat generating component has a placement portion that is placed on the fixed portion and fixed to the fixed portion together with the fixed portion, The circuit unit according to claim 1 or claim 2, wherein by fixing the placement portion of the heat generating component to the fixed portion, the heat generating component is separated from the holding portion.

5. The circuit unit according to claim 4, wherein the holding portion includes a frame portion that surrounds the periphery of the opening window and projects inward of the case, and a held portion that projects from the peripheral wall portion of the heat generating component is placed on the protruding end surface of the frame portion.

6. The holding portion projects more inward of the case than the frame portion and includes a deflectable piece portion that is deflectable on the outer peripheral side of the opening window. The deflection piece portion has a locking claw portion provided at the protruding tip and protruding toward the inner peripheral side of the opening window. When the deflection piece portion is elastically deformed toward the outer peripheral side, assembly of the heat generating component and the pressing component to the frame portion is permitted. With the held portion of the heat generating component placed on the protruding end surface of the frame portion, the locking claw portion of the elastically restored deflection piece portion overlaps with the pressing component with a gap therebetween in the protruding direction of the frame portion. The circuit unit according to claim 5.

7. In a state of being fixed to the heat dissipation target, the fixed portion of the heat dissipation target is arranged inside the case beyond the protruding end surface of the frame portion in the protruding direction of the frame portion. The circuit unit according to claim 5.

8. The case has positioning bosses arranged at a plurality of locations around the opening window and protruding beyond the fixing portion. The pressing component has a plurality of positioning holes penetrating therethrough at positions corresponding to the positioning bosses and through which the positioning bosses are inserted. The circuit unit according to claim 1 or claim 2.

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