JP7696802B2 - Heat sink and mounting board - Google Patents

Description

The present invention relates to a heat sink and a mounting board.

A known fixing structure for heat-generating elements is one in which a power module mounted on a substrate is screwed to heat dissipation fins (heat sink), and the heat dissipation fins are screwed to the substrate (see, for example, Patent Document 1).

JP 2004-152859 A

When using a metal heat sink as a countermeasure against heat generation from elements mounted on a board, as in the structure described in Patent Document 1, screw fastening is required in two places. This (1) increases the number of parts and labor, and (2) limits the layout of the mounting board to ensure space for tools during the screw fastening work. In addition, making the heat sink out of metal increases the weight of the heat sink, which can cause the board to warp.

In view of the above circumstances, the present invention aims to provide a heat sink and a mounting board that can reduce the number of parts and labor required, reduce layout constraints on the mounting board, and make the mounting board lighter, compared to when a metal heat sink is used.

The heat sink of the present invention is a heat sink made of thermally conductive resin that fixes an element mounted on a substrate and that generates heat when in operation to the substrate, and comprises 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 dissipation fins extending to the side opposite the heat receiving surface so that the end on the substrate side is included in the contact surface, an engagement portion that extends toward the substrate from the tip of the end of the heat dissipation fin on the substrate side and engages with an engaged portion formed on the substrate, and a holding portion that extends toward the element from the surface of the heat sink body opposite the contact surface and holds the element pressed against the heat receiving surface of the heat sink body.
In addition, the heat sink of the present invention is a heat sink made of thermally conductive resin that fixes an element mounted on a substrate and that generates heat when in operation to the substrate, and comprises 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 dissipation fins extending to the opposite side of the heat receiving surface so that the end on the substrate side is included in the contact surface, an engagement portion that extends toward the substrate from the tip of the end of the heat dissipation fin on the substrate side and engages with an engaged portion formed on the substrate, and a holding portion that is provided in a pair to sandwich the element in a direction perpendicular to the height direction of the element, engages with the end of the element in the direction perpendicular to the height direction, extends from the heat sink body toward the element, and holds the element in a state pressed against the heat receiving surface of the heat sink body, and the engagement portion comprises an axis portion that is inserted from the tip of the end of the heat dissipation fin on the substrate side into a hole as the engaged portion, and a claw portion that protrudes from the axis portion and engages with the edge of the hole.

The mounting board of the present invention comprises a substrate, an element mounted on the substrate and generating heat when in operation, and a heat sink made of thermally conductive resin for fixing the element to the substrate, the heat sink comprising a heat sink body having a contact surface for contacting the substrate, a heat receiving surface for receiving heat from the element , and a plurality of heat dissipation fins extending to the side opposite the heat receiving surface so that the end portion on the substrate side is included in the contact surface, an engagement portion extending from the tip of the end portion on the substrate side of the heat dissipation fin towards the substrate and engaging with an engaged portion formed on the substrate, and a holding portion extending towards the element from the surface of the heat sink body opposite the contact surface and holding the element pressed against the heat receiving surface of the heat sink body.
The mounting board of the present invention includes a substrate, an element mounted on the substrate and generating heat during operation, and a heat sink made of thermally conductive resin for fixing the element to the substrate, the heat sink including 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 dissipation fins extending to the side opposite the heat receiving surface so that the end of the heat dissipation fin on the substrate side is included in the contact surface, and an engagement portion that extends from the tip of the end of the heat dissipation fin on the substrate side to engage with an engagement portion formed on the substrate. The heat sink body has a mating portion, and an engaging piece that is arranged in a pair to sandwich the element in a direction perpendicular to the height direction of the element and engages with the end of the element in the direction perpendicular to the height direction, and extends from the heat sink body toward the element and holds the element pressed against the heat receiving surface of the heat sink body, and the engaging portion has an axis portion that is inserted from the tip of the end of the heat dissipation fin on the substrate side into a hole as the engaged portion, and a claw portion that protrudes from the axis portion and engages with the edge of the hole.

The present invention can reduce the number of parts and labor required compared to using a metal heat sink, reduce layout constraints on the mounting board, and make the mounting board lighter.

FIG. 1 is a side view showing a mounting board equipped with a heat sink according to an embodiment of the present invention. FIG. 2 is a perspective view showing the mounting board of FIG. 1 from diagonally above and in front, with the board not shown. 3 is a perspective view showing the mounting board of FIG. 1 from diagonally above and behind, with the board not shown. FIG. 4 is a side cross-sectional view showing a state in which the mounting board of FIG. 1 is assembled. FIG. 5 is an enlarged cross-sectional side view showing the mounting board of FIG. 4 in an assembled state. FIG. 6 is a side view showing a mounting board provided with a heat sink according to another embodiment of the present invention. 7 is a perspective view showing the mounting board of FIG. 6 from diagonally above and in front, with the board not shown. 8 is a perspective view showing the mounting board of FIG. 6 from diagonally above and behind, with the board not shown. 9 is a perspective view showing the mounting board of FIG. 6 from diagonally below and in front, with the board not shown. FIG. 10 is a side cross-sectional view showing a state in which the mounting board of FIG. 6 is assembled.

The present invention will be described below in accordance with a preferred embodiment. Note that the present invention is not limited to the embodiment described below, and can be modified as appropriate without departing from the spirit of the present invention. In addition, in the embodiment described below, some configurations are omitted from illustration and description, but for the details of the omitted technology, publicly known or well-known technology is applied as appropriate within the scope of not causing any inconsistencies with the contents described below.

Figure 1 is a side view showing a mounting substrate 1 equipped with a heat sink 10 according to one 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 10.

The substrate 2 is a circuit board on which the elements 3 and the like are mounted. The substrate 2 is formed with a plurality of slits 21 for connecting terminals and a pair of engagement holes 22. The plurality of slits 21 are formed side by side in the depth direction in the figure. The pair of engagement holes 22 are also formed side by side in the depth direction in the figure.

Figure 2 is a perspective view of the mounting board 1 in Figure 1 from diagonally above and in front, with the board 2 not shown. Furthermore, Figure 3 is a perspective view of the mounting board 1 in Figure 1 from diagonally above and in back, with the board 2 not shown.

The element 3 shown in Figures 1 to 3 is an electronic component that generates heat by itself when electricity is passed through it, such as a high-current transistor or a resistor with high power consumption. This element 3 comprises a thin, rectangular parallelepiped element body 31, which is the heat generating part, and multiple lead wires 32. Each of the multiple lead wires 32 is inserted into a slit 21 (see Figure 1) in the substrate 2 and soldered to the substrate 2 (see Figure 1).

As shown in FIG. 1, the element 3 is mounted on the substrate 2 so as to rise vertically from one surface of the substrate 2. The multiple lead wires 32 extend from the surface of the element body 31 facing the substrate 2 (hereinafter referred to as the bottom surface) toward the substrate 2 and are inserted into the slits 21. 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) or the heat sink 10 (or the heat sink body 11), and the direction in which the multiple 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) or the heat sink 10 (or the heat sink body 11). 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, with the element 3 side referred to as the front side and the heat sink 10 side referred to as the rear side.

As shown in Figures 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 containing other compounding agents. The resin is not particularly limited, but examples thereof include polyamide resin, polycarbonate resin, polybutylene terephthalate resin, etc. The thermally conductive filler is not particularly limited, but examples thereof include metal compound-based thermally conductive fillers such as metal nitrides, metal oxides, metal hydroxides, metal carbides, and metal carbonates. The thermally conductive filler may have any shape, such as fibers, particles, or plates.

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

The heat dissipation material 4 is a thermally conductive grease or sheet material that conducts heat generated by the element body 31 to the heat sink body 11. The heat dissipation material 4 is made of a compressible and deformable material, 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.

The multiple fins 111 extend on the side opposite the heat receiving surface 112. The lower surface of the heat sink body 11 (the surface on the lower side in the height direction) serves as a contact surface 113 that comes into contact with the substrate 2. The contact surface 113 includes the lower surfaces of the multiple fins 111.

The pair of lances 12 extend from near the contact surface 113 of the heat sink body 11 toward the substrate 2. Specifically, one lance 12 extends from the tip of the leftmost fin 111, and the other lance 12 extends from the tip of the rightmost fin 111. The pair of lances 12 have sufficient rigidity not to bend.

A pair of engagement holes 22 are provided corresponding to a pair of lances 12. Specifically, one engagement hole 22 is provided facing the tip of the leftmost fin 111, and the other engagement hole 22 is provided facing the tip of the rightmost fin 111. Each engagement hole 22 is a rectangular through hole.

In response to this, each lance 12 has a rectangular columnar shaft portion 121 that is inserted into each engagement hole 22, and a claw portion 122 that engages with the edge of each engagement hole 22. The shaft portion 121 extends from the tip of the fin 111 at the left or right end. The claw portion 122 is a protrusion that is a right-angled triangle in side view and protrudes from the tip side of the shaft portion 121 to the rear side (the side opposite the heat-receiving surface 112). On the underside of the substrate 2, the claw portion 122 and the edge of the engagement hole 22 engage with each other.

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

Each lance 13 comprises a frame portion 131 and a guide portion 132. The frame portion 131 is a U-shaped frame in a plan view and an L-shaped frame in a side view. The frame portion 131 comprises a pair of legs 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 legs 131A. The pair of legs 131A abut against the rear surface of the element body 31, and the pressing portion 131B abuts against the upper surface of the element body 31. The tip of the pressing portion 131B is located forward of the front surface of the element body 31.

The guide portion 132 is a plate extending diagonally downward from the tip of the pressing portion 131B to the front side. As will be described in detail later, the guide portion 132 and the frame portion 131 cooperate to fix each lance 13 to the upper end of the element body 31. In addition, the pair of lances 13 hold the element body 31 in a state where it is pressed against the heat receiving surface 112 of the heat sink body 11 via the heat dissipation material 4.

Figure 4 is a side cross-sectional view showing the state when the mounting board 1 of Figure 1 is assembled. As shown in this figure, the engagement hole 22 is an elongated hole with the longitudinal direction being the front-to-rear direction, and its long diameter is greater than the side length of the rectangular cross section of the shaft portion 121. This makes it possible to rotate the heat sink 10 with the edge of the engagement hole 22 and the shaft portion 121 abutting against each other at the abutment point P on the upper surface side of the board 2, when assembling the heat sink 10 to the mounting board 1 on which the element 3 is already mounted, using this abutment point P as a fulcrum.

Figure 5 is an enlarged side cross-sectional view showing the mounting board 1 of Figure 4 in an assembled state. As shown in Figure 4, when the heat sink 10 is rotated around the abutment point P as a fulcrum, as shown in Figure 5, the guide portion 132 of each lance 13 slides against the corner portion 31A on the front side of the upper end of the element body 31. As a result, each lance 13 is displaced to an engagement position with the upper end of the element body 31 in a state of elastic deformation.

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

As described above, the heat sink 10 of this embodiment is made of thermally conductive resin and is therefore lighter than a metal heat sink. This allows the weight of the entire mounting board 1 to be reduced compared to a mounting board that uses a metal heat sink, and suppresses warping of the board 2 caused by the weight of the heat sink 10.

In addition, a pair of lances 12 extend from the vicinity of the contact surface 113 of the heat sink body 11 toward the substrate 2, and a pair of lances 13 extend from the vicinity of the heat receiving surface 112 of the heat sink body 11 toward the element 3. 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 pressed against the heat receiving surface 112 of the heat sink body 11. This allows the element 3, which generates heat by itself when current is applied, to be fixed to the substrate 2 via the heat sink 10 without the need for screw fastening. Specifically, the element 3 can be fixed to the substrate 2 via the heat sink 10 without the need for screw fastening to fix the element 3 to the heat sink body 11 and the heat sink body 11 to the substrate 2. Therefore, the number of parts and the number of steps can be reduced compared to the case of using a metal heat sink. In addition, since there is no need to reserve space for tools during screw fastening work, there are no longer any limitations on the layout of the mounting board 1, and the design freedom of the mounting board 1 is increased.

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

The heat sink 10 of this embodiment is provided with these lances 12 and 13, so that it can be assembled to the board 2 on which the element 3 is already mounted. Specifically, as shown in FIG. 4, the shaft 121 of the lance 12 for engaging the board 2 is inserted into the engagement hole 22, the shaft 121 is brought into contact with the edge of the engagement hole 22, and the heat sink body 11 is rotated with the abutment point P as a fulcrum. Then, as shown in FIG. 5, the guide portion 132 of the lance 13 for holding the element 3 is brought into contact with the corner portion 31A at the upper end of the element body 31, and the pressing portion 131B of the lance 13 is fitted into the upper end of the element body 31 while elastically deforming the pressing portion 131B. Finally, the corner portion 132A on the base side of the guide portion 132 and the corner portion 31A on the upper front side of the element body 31 are fitted together, so that the lance 13 engages with the upper end of the element body 31.

Here, by constructing the heat sink 10 from resin, it is possible to configure the lance 13 for holding the element 3 to be elastically deformable. This makes it possible to rotate the heat sink body 11 around the abutment point P between the lance 12 and the engagement hole 22 of the substrate 2 as a fulcrum, and then elastically deform the lance 13 to engage 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 is already mounted.

Figure 6 is a side view showing a mounting substrate 1' equipped with 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 used for configurations similar to those of the above embodiment, and the description of the above embodiment is incorporated herein.

Figure 7 is a perspective view of the mounting board 1' in Figure 6 from diagonally above and in front, with the board 2 not shown. Also, Figure 8 is a perspective view of the mounting board 1' in Figure 6 from diagonally above and in rear, with the board 2 not shown. Furthermore, Figure 9 is a perspective view of the mounting board 1' in Figure 6 from diagonally below and in front, with the board 2 not shown.

As shown in Figures 6 to 9, the heat sink 100 comprises a heat sink body 101, a pair of lances 102, and two pairs of lances 103. As in the above embodiment, the heat sink 100 is a heat dissipation component made of thermally conductive resin.

The heat sink body 101 is a rectangular parallelepiped block body, and has multiple fins 1011 arranged in the left-right direction of the heat sink body 101. The heat sink body 101 has a heat receiving surface 1012 that faces the back surface (one of the main surfaces) of the element body 31. This heat receiving surface 1012 and the back surface of the element body 31 are pressed against each other via the 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.

In the heat sink body 101, the multiple fins 1011 extend on the side opposite the heat receiving surface 1012. The lower surface of the heat sink body 101 (the surface on the lower side in the height direction) serves as a contact surface 1013 that comes into contact with the substrate 2. The contact surface 1013 includes the lower surfaces of the multiple fins 1011 excluding the fins 1011 on both the left and right ends. The lower ends of the fins 1011 on both the left and right ends are located higher (higher in the height direction) than the lower ends of the multiple fins 1011 in the center.

The pair of lances 102 extend from the lower ends of the fins 1011 on both the left and right ends of the heat sink body 101 toward the substrate 2. Specifically, one lance 102 extends from the tip of the leftmost fin 1011, and the other lance 102 extends from the tip of the rightmost fin 1011. The pair of lances 102 are flexible.

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

In response to this, each lance 102 has a rectangular columnar shaft portion 1021 that is inserted into each engagement hole 22, and a claw portion 1022 that engages with the edge of each engagement hole 22. The shaft portion 1021 extends from the tip of the left or right end fin 1011. The claw portion 1022 is a protrusion that is a right-angled triangular shape in side view and protrudes from the tip side of the shaft portion 1021 to the rear side (the side opposite the heat receiving surface 112). On the underside of the substrate 2, the claw portion 1022 and the edge of the engagement hole 22 engage with each other. Here, the shaft portion 1021 is configured to be elastically deformable.

As shown in Figures 6 to 9, two pairs of lances 103 extend from the front ends of the left and right side surfaces of the heat sink body 101 towards the element 3. Two lances 103 are arranged symmetrically 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 arranged side by side in the height direction. Each lance 103 has a rigidity that does not deflect.

Each lance 103 comprises a frame portion 1031 and a guide portion 1032. The frame portion 1031 is a U-shaped frame in a side view and an L-shaped frame in a plan view. The frame portion 1031 comprises a pair of legs 1031A extending laterally from the side of the heat sink body 101, and a U-shaped pressing portion 1031B extending forward from the tips of the pair of legs 1031A. The pair of legs 1031A abut against the rear surface of the element body 31, and the pressing portion 1031B abuts against the side surface of the element body 31. The tip of the pressing portion 1031B is located forward of the front surface of the element body 31.

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

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 right end of the element body 31, and the two pairs of lances 103 press the element body 31 against the heat receiving surface 1012 of the heat sink body 101 via the heat dissipation material 4.

Figure 10 is a side cross-sectional view showing the state when mounting board 1' of Figure 6 is assembled. As shown in this figure, engagement hole 22 is a long hole with the longitudinal direction being the front-to-rear direction, and its long diameter is greater than the side length of the rectangular cross section of shaft portion 1021. This makes it possible to insert lance 102 for engaging board 2 into engagement hole 22 while elastically deforming, and lead wire 32 into slit 21 when mounting element 3 attached to heat sink 100 on mounting board 1' on which element 3 has not yet been mounted.

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

Here, by providing these lances 102 and 103, the heat sink 100 of this embodiment can be assembled together with the substrate 2 on which the element 3 has not yet been mounted, when the element 3 is mounted. Specifically, the element 3 is attached to the heat sink 100 by inserting it 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 via the heat dissipation material 4. Then, as shown in FIG. 10, the claw portion 1022 of the lance 102 is abutted against the edge of the engagement hole 22, and the shaft portion 1021 of the lance 102 is elastically deformed while the lance 102 is pushed into the engagement hole 22. At this time, the lead wire 32 of the element 3 is inserted into the slit 21 of the substrate 2. Finally, the shaft 1021 of the lance 102 elastically returns to its original position, and the claw 1022 of the lance 102 engages with the edge of the engagement hole 22 of the substrate 2.

Here, by constructing the heat sink 100 from resin, it has become possible to configure the lances 102 for engaging with the board 2 to be elastically deformable. This makes it possible to push the lances 102 into the engaging holes 22 of the board 2 while elastically deforming them, with the element 3 held by the two pairs of lances 103 of the heat sink body 101, and then elastically return them to their original position to engage with the edge of the engaging holes 22 of the board 2. Therefore, the element 3 can be mounted on the board 2 while attached to the heat sink 100.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and modifications may be made without departing from the spirit of the present invention, and known or well-known technologies may be combined as appropriate. For example, in the above embodiment, two lances 12, 102 for engaging the substrate 2 are provided, but the number of lances 12, 102 may be increased or decreased. The number of lances 13, 103 for holding the element 3 may also be increased or decreased.

1: Mounting board 1': Mounting board 2: Board 22: Engagement hole (engaged portion, hole)
3: Element 4: Heat dissipation material 10: Heat sink 11: Heat sink body 112: Heat receiving surface 113: Contact surface 12: Lance (engagement portion)
121: Shaft portion 122: Claw portion 13: Lance (holding portion)
100: Heat sink 101: Heat sink body 1012: Heat receiving surface 1013: Contact surface 102: Lance (engagement portion)
1021: Shaft portion 1022: Claw portion 103: Lance (holding portion)

Claims (5)

A heat sink made of thermally conductive resin that fixes an element mounted on a substrate and that generates heat during operation to the substrate,
a heat sink body including 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 a side opposite to the heat receiving surface so that the end of the heat sink body on the substrate side is included in the contact surface;
an engaging portion extending from a tip of the end portion of the heat dissipation fin on the substrate side toward the substrate and engaging with an engaged portion formed on the substrate;
a holding portion extending toward the element from a surface of the heat sink body opposite the contact surface and holding the element in a pressed state against the heat receiving surface of the heat sink body. the holding portion is an elastic piece that extends from the surface of the heat sink body opposite to the contact surface toward the element and engages with an end of the element opposite to the substrate,
The heat sink of claim 1, wherein the engaging portion comprises an axis portion that is inserted from the tip of the end portion of the heat dissipation fin on the substrate side into a hole serving as the engaged portion, and a claw portion that protrudes from the axis portion toward the opposite side to the heat receiving surface side and engages with the edge of the hole. A heat sink made of thermally conductive resin that fixes an element mounted on a substrate and that generates heat during operation to the substrate,
a heat sink body including 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 a side opposite to the heat receiving surface so that the end of the heat sink body on the substrate side is included in the contact surface;
an engaging portion extending from a tip of the end portion of the heat dissipation fin on the substrate side toward the substrate and engaging with an engaged portion formed on the substrate;
a holding portion which is provided in a pair so as to sandwich the element in a direction perpendicular to the height direction of the element , which is an engagement piece that engages with an end of the element in the direction perpendicular to the height direction, which extends from the heat sink main body toward the element, and which holds the element in a state in which it is pressed against the heat receiving surface of the heat sink main body;
Equipped with
The engaging portion includes a shaft portion that is inserted from a tip of the end portion of the heat dissipating fin on the substrate side into a hole serving as the engaged portion, and a claw portion that protrudes from the shaft portion and engages with an edge of the hole.
heat sink . A substrate;
An element mounted on the substrate and generating heat when in operation;
a heat sink made of a thermally conductive resin that fixes the element to the substrate;
The heat sink is
a heat sink body including 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 a side opposite to the heat receiving surface so that the end of the heat sink body on the substrate side is included in the contact surface;
an engaging portion extending from a tip of the end portion of the heat dissipation fin on the substrate side toward the substrate and engaging with an engaged portion formed on the substrate;
a holding portion extending toward the element from a surface of the heat sink body opposite the contact surface and holding the element in a pressed state against the heat receiving surface of the heat sink body. A substrate;
An element mounted on the substrate and generating heat when in operation;
a heat sink made of thermally conductive resin that fixes the element to the substrate;
Equipped with
The heat sink is
a heat sink body including 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 a side opposite to the heat receiving surface so that the end of the heat sink body on the substrate side is included in the contact surface;
an engaging portion extending from a tip of the end portion of the heat dissipation fin on the substrate side toward the substrate and engaging with an engaged portion formed on the substrate;
a holding portion which is provided in a pair so as to sandwich the element in a direction perpendicular to the height direction of the element, which is an engagement piece that engages with an end of the element in the direction perpendicular to the height direction, which extends from the heat sink main body toward the element, and which holds the element in a state in which it is pressed against the heat receiving surface of the heat sink main body;
Equipped with
The mounting board includes an axis portion that is inserted from the tip of the end of the heat dissipation fin on the substrate side into a hole serving as the engaged portion, and a claw portion that protrudes from the axis portion and engages with the edge of the hole.

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