Heat sink and mounting substrate

Abstract

To provide a heat sink and a mounting board capable of reducing the number of parts and man-hours, reducing restrictions on the layout of a mounting board, and reducing the weight of the mounting board, as compared with the case of using a metal heat sink.SOLUTION: A heat sink 10 is made of a thermally conductive resin and fixes, to a substrate 2, an element 3 that is mounted on the substrate 2 and generates heat during operation. The heat sink comprises: a heat sink body 11 having a contact surface 113 that contacts the substrate 2 and a heat-receiving surface 112 that receives heat from the element 3; a lance 12 extending from the vicinity of the contact surface 113 of the heat sink body 11 toward the substrate 2 and engaging with the edge of an engagement hole 22 formed in the substrate 2; and a lance 13 extending from the vicinity of the heat-receiving surface 112 of the heat sink body 11 toward the element 3 and holding the element 3 while being pressed against the heat-receiving surface 112 of the heat sink body 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heat sink and a mounting substrate.

Background Art

[0002] As a fixing structure for a heat-generating element, a power module mounted on a substrate is screwed to a heat radiation fin (heat sink), and the heat radiation fin is screwed to the substrate (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When using a metal heat sink as a countermeasure against heat generation of an element mounted on a substrate, two screw fixings are required as in the structure described in Patent Document 1. As a result, (1) the number of parts and the man-hours increase, and (2) the layout of the mounting substrate is restricted in order to secure the space for the tool during the screw fixing operation. In addition, making the heat sink out of metal increases the weight of the heat sink, and there is a possibility that the substrate may warp due to the weight of the heat sink.

[0005] In view of the above circumstances, an object of the present invention is to provide a heat sink and a mounting substrate that can reduce the number of parts and man-hours, reduce the restrictions on the layout of the mounting substrate, and reduce the weight of the mounting substrate as compared with the case of using a metal heat sink.

Means for Solving the Problems

[0006] The heat sink of the present invention is a heat sink made of a thermally conductive resin that fixes an element mounted on a substrate and generating heat during operation to the substrate, and includes a contact surface that contacts the substrate and a heat receiving surface that receives heat from the element. , a plurality of heat dissipation fins extending to the opposite side of the heat receiving surface side so that the end portion on the substrate side is included in the contact surface A heat sink body including Heat dissipation fin the The tip at the end on the substrate side extends from the above to the substrate side and includes an engaging portion that engages with an engaged portion formed on the substrate, and the heat sink body at the The surface on the side opposite to the contact surface extends from the above to the element side and includes a holding portion that holds the element in a state of being pressed against the heat receiving surface of the heat sink body. Further, the heat sink of the present invention is a heat sink made of a thermally conductive resin that fixes an element mounted on a substrate and generating heat during operation to the substrate, and includes a contact surface that contacts the substrate, a heat receiving surface that receives heat from the element, and a plurality of heat dissipation fins extending to the opposite side of the heat receiving surface side so that the end portion on the substrate side is included in the contact surface. A heat sink body, an engaging portion extending from the tip of the end portion on the substrate side of the heat dissipation fin to the substrate side and engaging with an engaged portion formed on the substrate, and provided in pairs so as to sandwich the element in a direction orthogonal to the height direction of the element, and engaging with the end portion of the element in a direction orthogonal to the height direction of the element. An engaging piece, a holding portion extending from the heat sink body to the element side and holding the element in a state of being pressed against the heat receiving surface of the heat sink body, wherein the engaging portion includes a shaft portion inserted into a hole as the engaged portion from the tip of the end portion on the substrate side of the heat dissipation fin, and a claw portion protruding from the shaft portion and engaging with the edge of the hole.

[0007] The mounting substrate of the present invention includes a substrate, an element mounted on the substrate and generating heat during operation, and a heat sink made of a thermally conductive resin that fixes the element to the substrate. The heat sink includes a contact surface that contacts the substrate and a heat receiving surface that receives heat from the element. , a plurality of heat dissipation fins extending to the opposite side of the heat receiving surface side so that the end portion on the substrate side is included in the contact surface A heat sink body including Heat dissipation fin the The tip at the end on the substrate side extends from the above to the substrate side and includes an engaging portion that engages with an engaged portion formed on the substrate, and the heat sink body at the The surface on the side opposite to the contact surface extends from the above to the element side and includes a holding portion that holds the element in a state of being pressed against the heat receiving surface of the heat sink body. Further, the mounting substrate of the present invention includes a substrate, an element mounted on the substrate that generates heat during operation, and a heat sink made of a thermally conductive resin that fixes the element to the substrate. The heat sink includes a contact surface that contacts the substrate, a heat receiving surface that receives heat from the element, and a plurality of heat dissipation fins that extend to the opposite side of the heat receiving surface side so that the end on the substrate side is included in the contact surface. A heat sink body, an engaging portion that extends from the tip of the end on the substrate side of the heat dissipation fin to the substrate side and engages with an engaged portion formed on the substrate, and is provided in a pair so as to sandwich the element in a direction orthogonal to the height direction of the element. An engaging piece that engages with an end portion of the element in a direction orthogonal to the height direction of the element, extends from the heat sink body to the element side, and includes a holding portion that holds the element in a state of being pressed against the heat receiving surface of the heat sink body. The engaging portion includes a shaft portion that is inserted into a hole as the engaged portion from the tip of the end on the substrate side of the heat dissipation fin, and a claw portion that protrudes from the shaft portion and engages with the edge of the hole.

Advantages of the Invention

[0008] According to the present invention, compared with the case of using a metal heat sink, the number of parts and man-hours can be reduced, the restrictions on the layout of the mounting substrate can be reduced, and the mounting substrate can be lightened.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be appropriately changed without departing from the gist of the present invention. Further, in the embodiments shown below, there are some places where the illustration and description of some configurations are omitted. However, regarding the details of the omitted technology, well-known or widely known technologies are appropriately applied within the range where no contradiction occurs with the content described below.

[0011] Figure 1 is a side view showing a mounting substrate 1 provided with a heat sink 10 according to an embodiment of the present invention. As shown in this figure, the mounting substrate 1 of the present embodiment includes a substrate 2, an element 3, a heat dissipation material 4, and a heat sink 10.

[0012] The substrate 2 is a circuit board on which elements 3 etc. are mounted. A plurality of slits 21 for terminal connection and a pair of engagement holes 22 are formed in this substrate 2. The plurality of slits 21 are formed side by side in the depth direction in the figure. Also, the pair of engagement holes 22 are formed side by side in the depth direction in the figure.

[0013] FIG. 2 is a perspective view showing the mounting substrate 1 of FIG. 1 from the front upper diagonal without showing the substrate 2. Further, FIG. 3 is a perspective view showing the mounting substrate 1 of FIG. 1 from the rear upper diagonal without showing the substrate 2.

[0014] The element 3 shown in FIGS. 1 to 3 is an electronic component that self-heats when energized, for example, a transistor for high current or a resistor with high power consumption. This element 3 includes a thin rectangular parallelepiped element body 31 which is a heat generating part and a plurality of lead wires 32. Each of the plurality of lead wires 32 is inserted into the slit 21 (see FIG. 1) of the substrate 2 and soldered to the substrate 2 (see FIG. 1).

[0015] As shown in FIG. 1, the element 3 is mounted on the substrate 2 so as to stand vertically from one surface of the substrate 2. The plurality of lead wires 32 extend from the surface (hereinafter referred to as the lower surface) of the element body 31 facing the substrate 2 toward the substrate 2 side and are inserted through the slits 21. Note that the normal direction of the substrate 2 (the vertical direction in FIG. 1) is referred to as the height direction of the element 3 (or the element body 31) and the heat sink 10 (or the heat sink body 11), and the direction in which the plurality of lead wires 32 are arranged (the depth direction in FIG. 1) is referred to as the left-right direction of the element 3 (or the element body 31) and the heat sink 10 (or the heat sink body 11). Also, the direction in which the element 3 and the heat sink 10 are arranged (the left-right direction in FIG. 1) is referred to as the front-rear direction, the element 3 side is referred to as the front side, and the heat sink 10 side is referred to as the rear side.

[0016] As shown in FIGS. 1 to 3, the heat sink 10 includes a heat sink body 11, a pair of lances 12, and a pair of lances 13. Here, the heat sink 10 is a heat dissipation component made of a thermally conductive resin. The thermally conductive resin is, for example, a thermally conductive resin composition containing a resin and a thermally conductive filler, and optionally other compounding agents. The resin is not particularly limited, and examples include polyamide-based resins, polycarbonate resins, polybutylene terephthalate resins, and the like. The thermally conductive filler is not particularly limited, and examples include metal compound-based thermally conductive fillers such as metal nitrides, metal oxides, metal hydroxides, metal carbides, and metal carbonates. Note that the shape of the thermally conductive filler may be any shape such as fibrous, particulate, or plate-like.

[0017] The heat sink body 11 is a rectangular parallelepiped block body and includes a plurality of fins 111 arranged in the left-right direction of the heat sink body 11. The heat sink body 11 includes a heat receiving surface 112 that faces the back surface (one main surface) of the element body 31. The heat receiving surface 112 and the back surface of the element body 31 are pressed against each other via a heat dissipation material 4.

[0018] The heat dissipation material 4 is a thermally conductive grease or sheet material that conducts the heat generated by the element body 31 to the heat sink body 11. Further, the heat dissipation material 4 is made of a material that can be compressed and deformed, and is interposed in a compressed and deformed state between the back surface of the element body 31 and the heat receiving surface 112 of the heat sink body 11.

[0019] The plurality of fins 111 extend to the side opposite to the heat receiving surface 112 side. Further, the lower surface (the surface on the lower position side in the height direction) of the heat sink body 11 serves as a contact surface 113 that contacts the substrate 2. The contact surface 113 includes the lower surfaces of the plurality of fins 111.

[0020] The pair of lances 12 extend from the vicinity of the contact surface 113 of the heat sink body 11 toward the substrate 2 side. Specifically, one lance 12 extends from the position of the tip of the leftmost fin 111, and the other lance 12 extends from the position of the tip of the rightmost fin 111. The pair of lances 12 have rigidity such that they do not bend.

[0021] The pair of engaging holes 22 are provided corresponding to the pair of lances 12. Specifically, one engaging hole 22 is provided opposite to the position of the tip of the fin 111 at the left end, and the other engaging hole 22 is provided opposite to the position of the tip of the fin 111 at the right end. Each engaging hole 22 is a rectangular through-hole.

[0022] On the other hand, each lance 12 includes a rectangular columnar shaft portion 121 inserted into each engaging hole 22 and a claw portion 122 engaging with the edge of each engaging hole 22. The shaft portion 121 extends from the position of the tip of the fin 111 at the left end or the right end. Also, the claw portion 122 is a convex portion having a right-angled triangular shape in a side view that protrudes from the tip side of the shaft portion 121 to the rear side (the side opposite to the heat receiving surface 112 side). On the lower surface side of the substrate 2, the claw portion 122 and the edge of the engaging hole 22 are engaged with each other.

[0023] The pair of lances 13 extend from the end of the upper surface (the surface opposite to the contact surface 113) 114 of the heat sink body 11 toward the element 3 side. Specifically, the pair of lances 13 are provided side by side in the left-right direction at the end on the element 3 side of the upper surface 114. The pair of lances 13 are elastic pieces configured to be elastically deformable.

[0024] Each lance 13 includes a frame portion 131 and a guide portion 132. The frame portion 131 is a frame having a U shape in a plan view and an L shape in a side view. This frame portion 131 includes a pair of leg portions 131A extending upward from the upper surface 114 of the heat sink body 11 and a U-shaped pressing portion 131B extending forward from the tips of the pair of leg portions 131A. The pair of leg portions 131A are in contact with the back surface of the element body 31, and the pressing portion 131B is in contact with the upper surface of the element body 31. The tip of the pressing portion 131B is located in front of the front surface of the element body 31.

[0025] The guide portion 132 is a plate piece that extends obliquely downward to the front side from the tip of the pressing portion 131B. Although details will be described later, due to the cooperation of this guide portion 132 and the frame portion 131, each lance 13 is fixed to the upper end of the element body 31. Further, the element body 31 is held in a state of being pressed against the heat receiving surface 112 of the heat sink body 11 via the heat dissipation material 4 by the pair of lances 13.

[0026] FIG. 4 is a side sectional view showing the state at the time of assembling the mounting substrate 1 of FIG. 1. As shown in this figure, the engagement hole 22 is an elongated hole having the longitudinal direction in the front-rear direction, and the major axis thereof is larger than the side length of the rectangular cross section of the shaft portion 121. Thereby, when assembling the heat sink 10 to the mounting substrate 1 on which the element 3 has been mounted, with the edge of the engagement hole 22 and the shaft portion 121 being brought into contact with each other at the contact point P on the upper surface side of the substrate 2, the heat sink 10 can be rotated with this contact point P as a fulcrum.

[0027] FIG. 5 is an enlarged side sectional view showing the state at the time of assembling the mounting substrate 1 of FIG. 4. As shown in FIG. 4, when rotating the heat sink 10 with the contact point P as a fulcrum, as shown in FIG. 5, the guide portion 132 of each lance 13 slides with respect to the corner portion 31A on the front surface side of the upper end of the element body 31. Thereby, each lance 13 is displaced to the engagement position with the upper end of the element body 31 in a state of being elastically deformed.

[0028] Here, a right-angled corner portion 132A is formed between the base side of the guide portion 132 and the tip side of the pressing portion 131B, and this corner portion 132A engages with the corner portion 31A on the front surface side of the upper end of the element body 31. Thereby, the pair of lances 13 are fixed to the upper end of the element body 31.

[0029] As described above, since the heat sink 10 of the present embodiment is made of a thermally conductive resin, it is lighter than a heat sink made of metal. As a result, compared with a mounting substrate using a metal heat sink, the weight of the entire mounting substrate 1 can be reduced, and warping of the substrate 2 caused by the weight of the heat sink 10 can be suppressed.

[0030] Also, a pair of lances 12 extend from near the contact surface 113 of the heat sink body 11 toward the substrate 2 side, and a pair of lances 13 extend from near the heat receiving surface 112 of the heat sink body 11 toward the element 3 side. The pair of lances 12 engage with the edge of the engagement hole 22 of the substrate 2, and the pair of lances 13 hold the element 3 in a state of pressing it against the heat receiving surface 112 of the heat sink body 11. As a result, the element 3 that self-heats upon energization can be fixed to the substrate 2 via the heat sink 10 without the need for screwing. Specifically, the element 3 can be fixed to the substrate 2 via the heat sink 10 without the need for screwing for fixing the element 3 to the heat sink body 11 and screwing for fixing the heat sink body 11 to the substrate 2. Therefore, compared with the case of using a metal heat sink, the number of parts and man-hours can be reduced. Also, since there is no need to secure space for tools during the screwing operation, there is no restriction on the layout of the mounting substrate 1 for that purpose, and the degree of freedom in designing the mounting substrate 1 is increased.

[0031] Also, in the heat sink 10 of the present embodiment, the lance 13 for holding the element 3 is an elastic piece that extends from a position on the side opposite to the contact surface 113 side (the upper side in the height direction) of the heat sink body 11 toward the element 3 side, and engages with the end portion on the side opposite to the substrate 2 side (the upper side in the height direction) of the element 3. On the other hand, the lance 12 for engaging with the substrate 2 includes a shaft portion 121 that is inserted into the engagement hole 22 of the substrate 2 from a position on the side opposite to the heat receiving surface 112 side (the rear side in the front-rear direction) of the heat sink body 11, and a claw portion 122 that protrudes from the shaft portion 121 and engages with the edge of the engagement hole 22.

[0032] By including these lances 12 and 13, the heat sink 10 of this embodiment can be assembled to the substrate 2 on which the element 3 has been mounted. Specifically, as shown in FIG. 4, the shaft portion 121 of the lance 12 for engaging with the substrate 2 is inserted into the engagement hole 22, the shaft portion 121 is brought into contact with the edge of the engagement hole 22, and the heat sink body 11 is rotated with the contact point P as a fulcrum. Then, as shown in FIG. 5, while bringing the guide portion 132 of the lance 13 for holding the element 3 into contact with the corner portion 31A at the upper end of the element body 31 and elastically deforming the pressing portion 131B of the lance 13, the pressing portion 131B is fitted onto the upper end of the element body 31. Finally, the lance 13 engages with the upper end of the element body 31 when the corner portion 132A on the base side of the guide portion 132 and the corner portion 31A on the front side of the upper end of the element body 31 fit together with each other.

[0033] Here, by forming the heat sink 10 of resin, it has become possible to configure the lance 13 for holding the element 3 to be elastically deformable. As a result, after rotating the heat sink body 11 with the contact point P between the lance 12 and the engagement hole 22 of the substrate 2 as a fulcrum, it has become possible to elastically deform the lance 13 and engage it with the upper end of the element body 31. Therefore, the heat sink 10 can be assembled to the substrate 2 on which the element 3 has been mounted.

[0034] FIG. 6 is a side view showing a mounting substrate 1' including a heat sink 100 according to another embodiment of the present invention. As shown in this figure, the mounting substrate 1' of this embodiment includes a substrate 2, an element 3, a heat dissipation material 4, and a heat sink 100. Note that the same reference numerals are given to the same configurations as those in the above embodiment, and the description of the above embodiment is incorporated herein.

[0035] FIG. 7 is a perspective view showing the mounting substrate 1' of FIG. 6 from obliquely above in the front with the substrate 2 not shown. FIG. 8 is a perspective view showing the mounting substrate 1' of FIG. 6 from obliquely above in the rear with the substrate 2 not shown. Further, FIG. 9 is a perspective view showing the mounting substrate 1' of FIG. 6 from obliquely below in the front with the substrate 2 not shown.

[0036] As shown in FIGS. 6 to 9, the heat sink 100 includes a heat sink body 101, a pair of lances 102, and two pairs of lances 103. The heat sink 100 is a heat dissipation component made of a thermally conductive resin, similar to the above-described embodiment.

[0037] The heat sink body 101 is a rectangular parallelepiped block body and includes a plurality of fins 1011 arranged in the left-right direction of the heat sink body 101. The heat sink body 101 includes a heat receiving surface 1012 that faces the back surface (one main surface) of the element body 31. The heat receiving surface 1012 and the back surface of the element body 31 are pressed against each other via a heat dissipation material 4. The width (length in the left-right direction) of the heat receiving surface 1012 is narrower than the width (length in the left-right direction) of the element body 31.

[0038] In the heat sink body 101, the plurality of fins 1011 extend to the side opposite to the heat receiving surface 1012 side. Also, the lower surface (the surface on the lower side in the height direction) of the heat sink body 101 is a contact surface 1013 that contacts the substrate 2. The contact surface 1013 includes the lower surfaces of the plurality of fins 1011 excluding the fins 1011 at both left and right ends. Note that the lower ends of the fins 1011 at both left and right ends are located on the upper side (the higher side in the height direction) than the lower ends of the plurality of fins 1011 on the central side.

[0039] The pair of lances 102 extend from the lower ends of the fins 1011 at both left and right ends of the heat sink body 101 toward the substrate 2 side. Specifically, one lance 102 extends from the position of the tip of the leftmost fin 1011, and the other lance 102 extends from the position of the tip of the rightmost fin 1011. The pair of lances 102 has flexibility.

[0040] As shown in FIG. 6, the pair of engagement holes 22 are provided corresponding to the pair of lances 102. Specifically, one engagement hole 22 is provided facing the position of the tip of the leftmost fin 1011, and the other engagement hole 22 is provided facing the position of the tip of the rightmost fin 1011.

[0041] On the other hand, each lance 102 includes a rectangular columnar shaft portion 1021 inserted into each engagement hole 22 and a claw portion 1022 engaged with the edge of each engagement hole 22. The shaft portion 1021 extends from the tip position of the fin 1011 at the left end or the right end. Further, the claw portion 1022 is a convex portion having a right-angled triangular shape in a side view that protrudes from the tip side of the shaft portion 1021 to the rear side (opposite side of the heat receiving surface 112 side). On the lower surface side of the substrate 2, the claw portion 1022 and the edge of the engagement hole 22 are engaged with each other. Here, the shaft portion 1021 is configured to be elastically deformable.

[0042] As shown in FIGS. 6 to 9, the two pairs of lances 103 extend from the front end portions on the left and right side surfaces of the heat sink body 101 toward the element 3 side. Two lances 103 are symmetrically arranged in the left-right direction of the heat sink body 101 to form a pair, sandwiching the element body 31 in the left-right direction. These two pairs of lances 103 are provided side by side in the height direction. Each lance 103 has rigidity such that it does not bend.

[0043] Each lance 103 includes a frame portion 1031 and a guide portion 1032. The frame portion 1031 is a frame having a U-shaped cross section in a side view and an L-shaped cross section in a plan view. This frame portion 1031 includes a pair of leg portions 1031A extending laterally from the side surface of the heat sink body 101 and a U-shaped pressing portion 1031B extending forward from the tips of the pair of leg portions 1031A. The pair of leg portions 1031A are in contact with the back surface of the element body 31, and the pressing portion 1031B is in contact with the side surface of the element body 31. The tip of the pressing portion 1031B is located in front of the front surface of the element body 31.

[0044] The guide portion 1032 is a convex portion having a right-angled triangular shape in a plan view that protrudes from the tip of the pressing portion 1031B toward the element 3 side. By sandwiching the element body 31 in its thickness direction between the guide portion 1032 and the leg portion 1031A of the frame portion 1031, each lance 103 fixes the left end or the right end of the element body 31.

[0045] Here, the tolerance between the distance between the guide portion 1032 and the leg portion 1031A and the thickness of the element body 31 is absorbed by the compressive deformation of the heat dissipation material 4. As a result, each lance 103 fixes the left end or the right end of the element body 31, and the pair of lances 103 presses the element body 31 against the heat receiving surface 1012 of the heat sink body 101 via the heat dissipation material 4.

[0046] FIG. 10 is a side sectional view showing the state at the time of assembling the mounting substrate 1' of FIG. 6. As shown in this figure, the engagement hole 22 is a long hole having the longitudinal direction in the front-rear direction, and its major axis is larger than the side length of the rectangular cross section of the shaft portion 1021. Thereby, when mounting the element 3 in a state where the element 3 is attached to the heat sink 100 with respect to the mounting substrate 1' on which the element 3 has not been mounted yet, the lance 102 for engaging with the substrate 2 is inserted into the engagement hole 22 while being elastically deformed, and the lead wire 32 can be inserted into the slit 21.

[0047] As described above, in the heat sink 100 of the present embodiment, the lance 103 for holding the element 3 is an engagement piece provided in a pair so as to sandwich the element 3 in the left-right direction of the element 3, and engages with the left and right ends of the element 3. On the other hand, the lance 102 for engaging with the substrate 2 includes an elastically deformable shaft portion 1021 that is inserted into the engagement hole 22 of the substrate 2 from a position on the side opposite to the heat receiving surface 1012 side (the rear side in the front-rear direction) of the heat sink body 101, and a claw portion 1022 that protrudes from the shaft portion 1021 and engages with the edge portion of the engagement hole 22.

[0048] Here, the heat sink 100 of the present embodiment includes these lances 102 and 103, and can be assembled together with the substrate 2 on which the element 3 has not been mounted when the element 3 is mounted. Specifically, the element 3 is attached to the heat sink 100 by inserting the element 3 between the two pairs of lances 103. At this time, the heat dissipation material 4 interposed between the element 3 and the heat receiving surface 1012 of the heat sink body 101 is compressed and deformed, so that the element 3 is pressed against the heat receiving surface 1012 through the heat dissipation material 4. Then, as shown in FIG. 10, while bringing the claw portion 1022 of the lance 102 into contact with the edge portion of the engagement hole 22 and elastically deforming the shaft portion 1021 of the lance 102, the lance 102 is pushed into the engagement hole 22. At this time, the lead wire 32 of the element 3 is inserted through the slit 21 of the substrate 2. Finally, the shaft portion 1021 of the lance 102 elastically returns, and the claw portion 1022 of the lance 102 engages with the edge portion of the engagement hole 22 of the substrate 2.

[0049] Here, by forming the heat sink 100 of resin, it becomes possible to configure the lance 102 for engaging with the substrate 2 to be elastically deformable. As a result, with the element 3 held by the two pairs of lances 103 of the heat sink body 101, the lance 102 can be pushed into the engagement hole 22 of the substrate 2 while being elastically deformed, and elastically returned to engage with the edge portion of the engagement hole 22 of the substrate 2. Therefore, the element 3 can be mounted on the substrate 2 in a state where the element 3 is attached to the heat sink 100.

[0050] The present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and modifications may be made without departing from the gist of the present invention, or known and well-known techniques may be appropriately combined. For example, in the above embodiment, two lances 12 and 102 for engaging with the substrate 2 are provided, but the number of the lances 12 and 102 may be increased or decreased. Also, the number of the lances 13 and 103 for holding the element 3 may be increased or decreased.

Explanation of Reference Numerals

[0051] 1: Mounting substrate 1’: Mounting substrate 2: Substrate 22: Engagement hole (engaged part, hole) 3: Element 4: Heat dissipation material 10: Heat sink 11: Heat sink body 112: Heat receiving surface 113: Contact surface 12: Lance (engaging part) 121: Shaft part 122: Claw part 13: Lance (holding part) 100: Heat sink 101: Heat sink body 1012: Heat receiving surface 1013: Contact surface 102: Lance (engaging part) 1021: Shaft part 1022: Claw part 103: Lance (holding part)

Claims

1. A heat sink made of a thermally conductive resin for fixing an element mounted on a substrate and generating heat during operation to the substrate, comprising a heat sink body having a contact surface that contacts the substrate, a heat receiving surface that receives heat from the element, and a plurality of heat radiating fins that extend to the opposite side of the heat receiving surface side so that the end on the substrate side is included in the contact surface, an engaging portion that extends from the tip of the end on the substrate side of the heat radiating fin to the substrate side and engages with an engaged portion formed on the substrate, and a holding portion that extends from the surface of the heat sink body opposite to the contact surface to the element side and holds the element in a state of being pressed against the heat receiving surface of the heat sink body. A heat sink comprising.

2. The holding portion is an elastic piece that extends from the surface of the heat sink body opposite to the contact surface to the element side and engages with the end of the element opposite to the substrate side, The engaging portion includes a shaft portion that is inserted into a hole as the engaged portion from the tip of the end on the substrate side of the heat radiating fin, and a claw portion that protrudes from the shaft portion to the opposite side of the heat receiving surface side and engages with the edge of the hole. The heat sink according to Claim 1.

3. A heat sink made of a thermally conductive resin for fixing an element mounted on a substrate and generating heat during operation to the substrate, comprising a heat sink body having a contact surface that contacts the substrate, a heat receiving surface that receives heat from the element, and a plurality of heat radiating fins that extend to the opposite side of the heat receiving surface side so that the end on the substrate side is included in the contact surface, an engaging portion that extends from the tip of the end on the substrate side of the heat radiating fin to the substrate side and engages with an engaged portion formed on the substrate, A pair of engaging pieces provided so as to sandwich the element in a direction orthogonal to the height direction of the element, the engaging pieces engaging with an end portion of the element in a direction orthogonal to the height direction of the element, extending from the heat sink body toward the element side, and holding the element in a state of being pressed against the heat receiving surface of the heat sink body. and comprising The engaging portion includes a shaft portion inserted into a hole as the engaged portion from a tip at an end portion on the substrate side of the radiation fin, and a claw portion protruding from the shaft portion and engaging with an edge portion of the hole. Heat sink.

4. A substrate, An element mounted on the substrate and generating heat during operation, A heat sink made of a thermally conductive resin for fixing the element to the substrate and comprising The heat sink includes a heat sink body having a contact surface in contact with the substrate, a heat receiving surface receiving heat from the element, and a plurality of radiation fins extending to the opposite side of the heat receiving surface side such that an end portion on the substrate side is included in the contact surface, an engaging portion extending from a tip at an end portion on the substrate side of the radiation fin toward the substrate side and engaging with an engaged portion formed on the substrate, and a holding portion extending from a surface opposite to the contact surface in the heat sink body toward the element side and holding the element in a state of being pressed against the heat receiving surface of the heat sink body. Mounting substrate.

5. A substrate, an element mounted on the substrate and generating heat during operation, a heat sink made of a thermally conductive resin for fixing the element to the substrate and comprising The heat sink includes a heat sink body having a contact surface in contact with the substrate, a heat receiving surface receiving heat from the element, and a plurality of radiation fins extending to the opposite side of the heat receiving surface side such that an end portion on the substrate side is included in the contact surface, An engaging portion that extends from the tip at the end of the heat dissipation fin on the substrate side to the substrate side and engages with an engaged portion formed on the substrate. An engaging piece that is provided in a pair so as to sandwich the element in a direction orthogonal to the height direction of the element and engages with an end portion of the element in a direction orthogonal to the height direction of the element. The engaging piece extends from the heat sink body toward the element side and holds the element in a state where the element is pressed against the heat receiving surface of the heat sink body. Comprising: The engaging portion includes a shaft portion that is inserted into a hole as the engaged portion from the tip at the end of the heat dissipation fin on the substrate side, and a claw portion that protrudes from the shaft portion and engages with an edge portion of the hole. The mounting substrate.

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