JP2010225949A - Heat dissipation structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat radiation structure, in which a contact area of a heat conductive piece brought into contact with a heating component, and a heat dissipating member with which the heat conductive piece is to be in contact, is increased. <P>SOLUTION: The heat radiation structure of a heating element has an electronic device 1 which is the heating element, the heat conductive piece 2 brought into contact with the electronic device 1, and a support member 3 for supporting the heat conductive piece 2. The heat conductive piece 2 has an abutment piece 20 prolonged obliquely and upwardly from a surface contacting the electronic device 1. An opening 31 for fitting the heat conductive piece 2 is formed in the support member 3. A guide piece 30 which is substantially parallel to the abutment piece 20, and brought into face contact with the abutment piece 20, projects from the peripheral section of the opening 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat dissipation structure for a heating element, and more particularly to a structure for dissipating heat generated from an electronic device such as an integrated circuit.

FIG. 5 is a cross-sectional view showing a structure for dissipating heat from a conventional electronic device (see Patent Document 1). This relates to a structure for radiating the heat of the electronic device (1) arranged in the shield case (9). On the lower surface of the circuit board (5) arranged in the shield case (9), an electronic device such as a CPU ( 1) is deployed. A metal heat conduction piece (2) provided with a convex portion (22) is provided on the bottom surface of the shield case (9), and the upper surface of the convex portion (22) is interposed via a heat dissipation sheet (not shown). In contact with the lower surface of the electronic device (1). Such an electronic device (1) has an upper limit on the operating temperature, and in order to avoid the electronic device (1) from becoming hot when the upper limit temperature is exceeded, a heat conducting piece (2) is provided to dissipate heat. Yes.
The shield case (9) is covered with a lid (90), and a projecting pressing portion (91) projects downward from the lid (90). The pressing portion (91) has elasticity and is in contact with the upper surface of the circuit board (5). That is, due to the elasticity of the pressing portion (91), the electronic device (1) is pressed against the convex portion (22) of the heat conducting piece (2) through the circuit board (5). Thereby, the electronic device (1) is surely in contact with the heat conducting piece (2), and the heat from the electronic device (1) escapes from the heat conducting piece (2) to the shield case (9).

JP 2007-194291 A

In the heat dissipation structure shown in FIG. 5, when there is a component protruding downward from the electronic device (1) in the vicinity of the electronic device (1) on the lower surface of the circuit board (5), in order to avoid the component, There is a limit to the size of the protrusion (22) and the heat conductive piece (2), specifically the lateral width. For this reason, when the width of the convex portion (22) and the heat conducting piece (2) is short, the heat dissipation effect may be weak. Therefore, it may be required to increase the contact area between the heat conductive piece (2) and the heat conductive member to which the heat conductive piece (2) should contact.
An object of the present invention is to provide a heat dissipating structure in which the contact area between the heat conducting piece (2) in contact with the heat generating component and the heat dissipating member to which the heat conducting piece (2) is in contact is increased.

  The heat dissipating structure of the heat generating body includes an electronic device (1) that is a heat generating body, a heat conductive piece (2) in contact with the electronic device (1), and a heat conductive support member that supports the heat conductive piece (2). (3) is provided. The heat conducting piece (2) has an abutting piece (20) extending obliquely from the surface in contact with the electronic device (1), and the support member (3) has an opening (31) in which the heat conducting piece (2) is fitted. Is formed. A guide piece (30) projecting from the peripheral edge of the opening (31) is substantially parallel to the contact piece (20) and is in surface contact with the contact piece (20).

The heat conduction piece (2) in contact with the electronic device (1) includes a contact piece (20) extending obliquely from the surface in contact with the electronic device (1), and a support member (3) supporting the heat conduction piece (2). ) Protrudes from the guide piece (30) in surface contact with the contact piece (20). Therefore, the contact piece (20) and the guide piece (30) extending obliquely from the surface in contact with the electronic device (1) are in contact with each other to dissipate heat.
Therefore, a large contact area between the contact piece (20) and the guide piece (30) can be provided. Specifically, the contact piece (20) and the guide piece (30) are compared with the structure (see FIG. 4) substantially orthogonal to the surface in contact with the electronic device (1). A large contact area of the piece (30) can be provided to enhance the heat dissipation effect.

It is sectional drawing which shows the use condition of a base station unit. It is sectional drawing which fractured | ruptured the circuit board and support member of FIG. 1 in the surface containing an AA line, and was seen by the arrow. It is a disassembled perspective view of the heat conductive piece and support member of FIG. It is sectional drawing which shows the example of the unpreferable support member. It is sectional drawing which shows the conventional heat dissipation structure. It is sectional drawing of another heat conductive piece and a supporting member.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The heat dissipation structure for an electronic device according to this example is used in a base station unit (4) that relays communication between a mobile phone and a telephone line in a mobile phone system such as a PHS (Personal Handyphone System).
As shown in FIG. 1, the base station unit (4) has a rectangular parallelepiped housing (40) that is hung on a wire (70) between utility poles (7) and (7) by using a hanging metal fitting (71). ) The interior of the housing (40) is partitioned by a partition plate (41), and an entrance chamber (42) provided with a terminal (45) connected to a telephone line cable (44), and the terminal (45) electrically A circuit chamber (43) provided with a connected circuit board (5) is formed. On the circuit board (5), as will be described later, a plate-like support member (3) having thermal conductivity and a heat dissipation effect is covered.

FIG. 2 is a sectional view of the circuit board (5) and the support member (3) of FIG. On the circuit board (5), an electronic device (1) such as a CPU as a heating element is attached. An opening (31) is formed above the electronic device (1) in the support member (3).
From the peripheral edge of the opening (31), a pair of guide pieces (30), (30) that are substantially parallel to each other are inclined downward, and the heat conducting piece (2) is located inside the guide pieces (30), (30). The guide pieces (30) and (30) are arranged so as to be slidable obliquely.
The heat conducting piece (2) is formed by bending a metal plate, a horizontal plate (21) substantially parallel to the circuit board (5), and a contact extending obliquely upward from the left and right ends of the horizontal plate (21). The pieces (20) and (20) are integrally formed. The contact pieces (20) and (20) are substantially parallel to the guide pieces (30) and (30) and are in surface contact with the guide pieces (30) and (30). A convex part (22) protrudes downward from the horizontal plate (21), and the lower surface of the convex part (22) is in contact with the upper surface of the electronic device (1). That is, the contact piece (20) extends obliquely upward from the surface in contact with the electronic device (1).

FIG. 3 is an exploded perspective view of the heat conducting piece (2) and the support member (3) of FIG. A leaf spring (8) is fixed to the peripheral edge of the opening (31) with screws (80) and (80), and the tip of the leaf spring (8) is the upper surface of the horizontal plate (21) of the heat conducting piece (2). To touch. That is, the convex part (22) of the heat conducting piece (2) is pressed against the electronic device (1) by the leaf spring (8), and the heat conducting piece (2) is in contact with the electronic device (1) without fail. Heat generated from the electronic device (1) is transmitted to the support member (3) through the heat conducting piece (2).
Here, the contact pieces (20) and (20) extending obliquely with respect to the horizontal plate (21) are in contact with the guide pieces (30) and (30) of the support member (3). Therefore, the contact length between the contact pieces (20) and (20) and the guide pieces (30) and (30) is long. In other words, as shown in FIG. 4, the contact pieces (20) and (20) are orthogonal to the horizontal plate (21), as shown in FIG. However, as compared with the configuration shown in FIG. 4, in this example, the contact length between the contact pieces (20) and (20) and the guide pieces (30) and (30) is longer. Thereby, the thermal radiation effect of a heat conductive piece (2) can be improved.

In recent years, electronic devices (1) such as CPUs and LSIs have been limited in stress applied for internal protection. Specifically, for example, the stress applied to the central portion of the CPU is regulated to be within about 4 kg.
In the conventional heat dissipation structure shown in FIG. 5, when the thickness of the electronic device (1) varies, the force with which the pressing portion (91) presses the electronic device (1) tends to vary, and the electronic device (1) If the thickness is thick, the allowable stress of the electronic device may be exceeded.
In the configuration shown in this example, when the electronic device (1) is thick, the heat conducting piece (2) slides upward along the guide piece (30). Therefore, the heat conducting piece (2) itself does not bend and deform to press the electronic device (1). Since the heat conducting piece (2) is pressed against the electronic device (1) by the elastic force of the leaf spring (8), the electronic device (1) is pushed by setting the spring constant of the leaf spring (8) small. It can suppress the variation of the power to do. Here, it is well known that the spring constant of the leaf spring (8) is inversely proportional to the cube of the length of the leaf spring (8), and proportional to the moment of inertia of the section, that is, the cube of the thickness of the leaf spring (8). Therefore, the spring constant of the leaf spring (8) can be set small by lengthening the leaf spring (8) and reducing the thickness. A plurality of leaf springs (8) having a small spring constant may be arranged side by side (not shown).

In this example, an opening (31) may be formed in the support member (3) in accordance with the location of the electronic device (1), and the heat conducting piece (2) may be fitted. Therefore, even if electronic devices to be radiated are scattered at a plurality of locations, the heat can be radiated by a single support member (3). That is, the support member (3) can be enlarged and the heat dissipation effect can be enhanced.
Further, an FPGA (Field Programmable Gate Array) and a coil may be provided around the electronic device (1), and some of these components are thicker than the electronic device (1). In the conventional configuration shown in FIG. 5, in order to avoid these parts, the size of the convex portion (22) and the heat conducting piece (2) is limited. For this reason, when the width of the convex portion (22) and the heat conducting piece (2) is short, the heat dissipation effect may be weak.
In contrast, in this example, the contact pieces (20) and (20) and the guide pieces (30) and (30) are inclined with respect to the horizontal plate (21), and the contact length is long. Thereby, the heat dissipation effect of the heat conductive piece (2) can be enhanced while avoiding parts thicker than the electronic device (1).

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.
The heat dissipation structure for an electronic device according to this example can be used not only for a base station unit but also for a mobile phone body and a personal computer. Moreover, as shown in FIG. 6, the guide pieces (30) and (30) may be inclined upward from the peripheral edge of the opening (31).

(1) Electronic device
(2) Heat conduction piece
(3) Support member
(4) Base station unit
(5) Circuit board
(20) Contact piece
(30) Guide piece
(31) Opening

Claims (4)

A heating element, a heat conducting piece (2) in contact with the heating element, and a heat dissipation member for supporting the heat conducting piece (2) are provided, and the heat conducting piece (2) extends obliquely upward from a surface in contact with the heating element. The heating element is characterized in that it has a contact piece (20), and a guide piece (30) projecting from the heat radiating member and being in parallel with the contact piece (20) and in surface contact with the contact piece (20). Heat dissipation structure. The heat-radiating structure for a heating element according to claim 1, wherein the heat conducting piece (2) is pressed against the heating element by an elastic member arranged on the heat-dissipating member. The heating element according to claim 1 or 2, wherein the heat dissipating member has an opening (31) into which the heat conducting piece (2) is fitted, and the guide piece (30) protrudes from a peripheral edge of the opening (31). Heat dissipation structure. The heat dissipating structure for a heating element according to claim 2, wherein the elastic member is a leaf spring (8) and the heating element is an electronic device (1).

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