Heat dissipation structure of heating element and heat medium heater

Abstract

[Problem] To provide a heat dissipation structure of a heating element and a heat medium heater that improve design flexibility around the heating element. [Solution] This heat dissipation structure of a heating element 40 comprises a housing 20 in which the heating element 40 mounted on a substrate 30 is disposed, and allows heat generated by the heating element 40 to be dissipated to the housing 20. The housing 20 has a pocket 21 that is open on a substrate-facing surface 20a facing the substrate 30 and is recessed away from the substrate 30. The heating element 40 is disposed in the pocket 21 with a lead protruding surface 41a of the heating element 40 facing the substrate 30.

Description

Heat dissipation structure for heat generating element and heat medium heater

[0001] The present invention relates to a heat dissipation structure for a heat generating element and a heat medium heater.

[0002] BACKGROUND ART A heat dissipation structure for a heat generating element, which includes a housing in which a heat generating element such as an IGBT mounted on a substrate is arranged and which dissipates heat generated by the heat generating element to the housing, is disclosed in Patent Document 1.

[0003] China Utility Model Publication No. 211788988

[0004] However, the heat dissipation structure for the heat generating element disclosed in Patent Document 1 leaves room for improvement in the degree of freedom in designing the periphery of the heat generating element.

[0005] Therefore, the present invention aims to solve these problems and provide a heat dissipation structure for a heat generating element and a heat medium heater that have a simple configuration and improve the design freedom around the heat generating element.

[0006] The heat dissipation structure for a heat generating element of the present invention includes a housing for arranging a heat generating element mounted on a substrate, and dissipating heat generated by the heat generating element toward the housing, the housing having a pocket that opens on a substrate-facing surface facing the substrate and is recessed toward a side away from the substrate, the heat generating element being disposed in the pocket with its lead protruding surface facing the substrate.The heat medium heater of the present invention is a heat medium heater having the heat dissipation structure for a heat generating element, the heat medium heater including a heat medium flow path provided in the housing and a heater for heating the heat medium flowing through the heat medium flow path, the pocket being provided to the side of the heat medium flow path in a lateral direction perpendicular to the substrate, which is perpendicular to the substrate.

[0007] According to the present invention, the degree of freedom in designing the periphery of the heat generating element can be improved with a simple configuration.

[0008] 1 is a cross-sectional view of a heat medium heater according to an embodiment of the present invention;

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat medium heater 10 according to an embodiment of the present invention will be described below with reference to the drawings.

[0010] First, the heat medium heater 10 is incorporated into an air conditioning system mounted on a vehicle such as an automobile, and heats a heat medium such as coolant (water), and is provided with a heat dissipation structure for the heat generating element 40, which dissipates heat generated by the heat generating element 40, as described below.

[0011] The specific configuration of the heat medium heater 10 will be described below with reference to the drawings.

[0012] As shown in FIG. 1 , the heat medium heater 10 includes a housing 20 for arranging various components, a substrate 30 arranged away from the housing 20, a heat generating element 40 mounted on the substrate 30, a heat medium flow path 50 provided within the housing 20, a heater 60 for heating the heat medium flowing through the heat medium flow path 50, a fixing member 70 for fixing the heat generating element 40, an insulating sheet 80 for insulating between the housing 20 and the heat generating element 40, and a heat dissipating filler 90 filled in the pocket 21 of the housing 20.

[0013] The housing 20 is made of metal or the like, and as shown in Fig. 1 , has a pocket 21 that opens on a substrate-facing surface 20a of the housing 20 facing the substrate 30 and is recessed so as to extend away from the substrate 30. This pocket 21 is a portion for arranging a heating element 40 or the like, and as shown in Fig. 1 , is formed so as to open only on the substrate-facing surface 20a side (substrate 30 side). As shown in Fig. 1 and Fig. 2 , the pocket 21 has inner walls that include a bottom surface 21a, inner side surfaces 21b on both sides in the lateral direction X, and inner side surfaces 21c on both sides in the flow path extending direction Z. As shown in Figs. 1 and 2 , the pocket 21 is provided on either side of the heat medium flow path 50 in the lateral direction X, and in this embodiment, the pockets 21 are provided on both sides of the heat medium flow path 50 in the lateral direction X (specifically, at positions facing each other in the lateral direction X).

[0014] The above-mentioned lateral direction X is a direction perpendicular to the substrate vertical direction Y, which is perpendicular to the substrate 30, and the flow path extension direction Z is a direction in which the heat medium flow path 50 extends and is perpendicular to the lateral direction X and the substrate vertical direction Y.

[0015] The substrate 30 is configured as a rigid type printed circuit board (electronic substrate) and includes printed wiring to which the leads 42 of the heating element 40 are electrically connected, various electronic components, etc. As shown in Fig. 1, the substrate 30 is disposed at a position spaced apart from the housing 20 (the substrate-facing surface 20a of the housing 20) in the board vertical direction Y, and is fixed to peripheral members such as the housing 20.

[0016] The heating element 40 is configured as a semiconductor element mounted on the substrate 30 and generates heat when energized, and in this embodiment is configured as an IGBT (Insulated Gate Bipolar Transistor) for controlling the on / off of the power supply to the heater 60. As shown in FIGS. 1 and 2 , the heating element 40 has a housing 41 made of synthetic resin or the like, and leads 42 made of metal that protrude from a lead protruding surface 41 a of the housing 41. As shown in FIG. 1 , the leads 42 extend toward the substrate 30 and are electrically connected to an electronic circuit (printed wiring, etc.) of the substrate 30 while being inserted into a through-hole formed in the substrate 30.

[0017] 1, a portion of the heating element 40 is disposed in each pocket 21 with the lead protruding surface 41a (leads 42) facing the substrate 30, and the heating element 40 is fixed to the housing 20 by being pressed in the lateral direction X toward the heat medium flow path 50 side (insulating sheet 80 side) by a fixing member 70 with an insulating sheet 80 interposed between the side of the heating element 40 facing the heat medium flow path 50 and the inner surface 21b of the pocket 21. Note that, when the heating element 40 is disposed in the pocket 21, as shown in FIGS. 1 and 2, there are gaps between the bottom surface 21a of the pocket 21 and the heating element 40, between each inner surface 21c of the pocket 21 and the heating element 40, and between the inner surface 21b of the pocket 21 opposite the heat medium flow path 50 side and the heating element 40, and these gaps are filled with a heat dissipating filler 90.

[0018] The heater 60 is configured as a heater that heats the heat medium, such as coolant (water), flowing through the heat medium flow path 50, and in this embodiment, as shown in Figures 1 and 2, is arranged on the inner periphery of the heat medium flow path 50, extending in the flow path extending direction Z. Note that the specific aspect and arrangement of the heater 60 may be any as long as it is capable of heating the heat medium flowing through the heat medium flow path 50.

[0019] The fixing member 70 is used to fix the heating element 40 to the housing 20. In this embodiment, as shown in FIG. 1 , the fixing member 70 is configured as a leaf spring installed on the side of the pocket 21 (heating element 40) in the horizontal direction X, specifically, on the opposite side of the heat medium flow path 50 across the pocket 21 (heating element 40) in the horizontal direction X. Note that the specific form and arrangement of the fixing member 70 may be any as long as it is capable of fixing the heating element 40 to the housing 20. Furthermore, the fixing member 70 may be attached to the housing 20 in any specific form, such as the fixing member 70 shown on the right side of FIG. 1 , which is attached to the housing 20 using bolts or the like, or the fixing member 70 shown on the left side of FIG. 1 , which is attached to the housing 20 by sandwiching a portion of the housing 20 between the fixing member 70.

[0020] 1, the insulating sheet 80 is disposed (at least a portion thereof) between the housing 20 and the heating element 40 within the pocket 21 to insulate the housing 20 from the heating element 40. The insulating sheet 80 also functions to transfer heat from the heating element 40 to the housing 20 and release it (radiate heat).

[0021] As shown in FIG. 1 , the heat-dissipating filler 90 is filled into the pocket 21 (specifically, the gap between the heating element 40 disposed in the pocket 21 and the inner wall of the pocket 21). In this embodiment, the heat-dissipating filler 90 is a filler such as silicone grease that is fluid when the pocket 21 is filled with the heat-dissipating filler 90 and solidifies after a certain period of time has passed since filling. The heat-dissipating filler 90 not only transfers heat from the heating element 40 to the housing 20 and dissipates it (radiates heat), but also provides insulation between the heating element 40 and the housing 20. Note that in this embodiment, the heat-dissipating filler 90 is a filler that solidifies after a certain period of time has passed since filling. However, the specific form of the heat-dissipating filler 90 may be any material that can radiate heat from the heating element 40 to the housing 20. For example, the heat-dissipating filler 90 may be a material that remains fluid even after a certain period of time has passed since filling.

[0022] The heat dissipation structure (heat medium heater 10) of the heat generating element 40 of this embodiment obtained in this manner can achieve the following effects.

[0023] (1) That is, in the heat dissipation structure (heat medium heater 10) of the heat generating element 40 of this embodiment, the housing 20 has a pocket 21 that is open at the substrate-facing surface 20a facing the substrate 30 and is recessed toward the side away from the substrate 30, and the heat generating element 40 is disposed in the pocket 21 with its lead protruding surface 41a facing the substrate 30. This allows the heat generating element 40 to be accommodated in the pocket 21, simplifying the relationship between the housing 20 and the substrate 30. In addition, for example, if the lead protruding surface 41a is disposed facing the lateral direction X, the leads 42 need to be bent approximately 90 degrees toward the substrate 30 when mounted on the substrate 30. However, in this embodiment, there is no need to bend the leads 42 (or the extent of bending is small) to change the direction in which the leads 42 extend when mounted on the substrate 30, so a large gap can be secured between the substrate-facing surface 20a of the housing 20 and the substrate 30. Furthermore, by ensuring a large gap between the housing 20 and the substrate 30, it becomes easier to ensure the insulation of the substrate 30, and the space between the substrate-facing surface 20a of the housing 20 and the substrate 30 can be more easily used as space for installing various electronic components, etc., thereby improving the design freedom of the surrounding environment of the heat-generating element 40 and enabling the device configuration to be designed compactly.

[0024] (2) Furthermore, the pockets 21, which are recessed in the substrate-facing surface 20a and open toward the side away from the substrate 30, are filled with thermally conductive filler 90. During manufacturing, when filling the pockets 21 containing the heat-generating elements 40 with the thermally conductive filler 90, the pockets 21 are filled with the thermally conductive filler 90 with the substrate-facing surface 20a facing upward. This allows the pockets 21 to receive the thermally conductive filler 90 and prevent it from flowing to the surrounding area. This ensures that the thermally conductive filler 90 is positioned in a desired manner, thereby improving the heat dissipation of the heat-generating elements 40. Furthermore, improved heat dissipation suppresses the temperature rise of each heat-generating element 40, thereby reducing the number of heat-generating elements 40 mounted, which is determined in relation to the temperature tolerance range. This reduces manufacturing costs and also secures more space by reducing the number of mounted elements, thereby improving the design flexibility of the surrounding environment. Furthermore, by adopting a structure that improves the heat dissipation properties of the heating element 40 using the heat dissipation filler 90, there is no need to provide a complex mechanism for dissipating heat from the heating element 40, which also simplifies the surrounding environment of the heating element 40.

[0025] (3) The heating element 40 is disposed in a pocket 21 provided on the side of the heat transfer medium flow path 50 in the horizontal direction X, with the lead protruding surface 41 a facing the substrate 30. This places no particular constraint on the design of the horizontal position of the heating element 40 (pocket 21), and therefore the distance between the heat transfer medium flow path 50 and the heating element 40 (pocket 21) in the horizontal direction X can be easily designed to be narrow. As a result, the cooling efficiency of the heating element 40 by the heat transfer medium flowing through the heat transfer medium flow path 50 can be improved.

[0026] (4) Furthermore, the pockets 21 in which the heating elements 40 are disposed are provided on both sides of the heat medium flow path 50 in the horizontal direction X, thereby improving the cooling efficiency of the heating elements 40 by the heat medium flowing through the heat medium flow path 50. That is, the heat medium in the heat medium flow path 50 is gradually heated by the heaters 60 extending in the flow path extension direction Z. Therefore, the temperature of the heat medium located on the upstream side (inlet side) of the heat medium flow path 50 is lower than the temperature of the heat medium located on the downstream side (outlet side) of the heat medium flow path 50. In this embodiment, by adopting a structure in which the pockets 21 (heating elements 40) are disposed on the sides of the heat medium flow path 50 in the horizontal direction X, both lateral sides of the upstream side (inlet side) of the heat medium flow path 50, where the temperature of the heat medium is low, can be used as installation locations for the heating elements 40. This improves the cooling efficiency of the heating elements 40 by the heat medium flowing through the heat medium flow path 50.

[0027] (5) The heating element 40 is disposed in the pocket 21 with the lead protruding surface 41 a facing the substrate 30, and the fixing member 70 is disposed on the opposite side of the pocket 21 (heating element 40) from the heat medium flow path 50 in the lateral direction X. This eliminates (or reduces) the need to consider interference between the leads 42 of the heating element 40 and the fixing member 70, ensuring design freedom for the fixing member 70. Furthermore, by disposing the fixing member 70 to the side of the heating element 40 in the lateral direction X, the fixing member 70 can be prevented from impairing the insulation of the substrate 30.

[0028] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design modifications can be made without departing from the present invention as defined in the claims, such as by arbitrarily combining the configurations of the above or following embodiments and modified examples to form a heat dissipation structure for the heat medium heater 10 and the heat generating element 40.

[0029] For example, in the above embodiment, the heat dissipation structure of the heat generating element 40 is described as being applied to the thermal medium heater 10, but the heat dissipation structure of the heat generating element 40 may also be applied to other devices.

[0030] In the above-described embodiment, the heating elements 40 (pockets 21) are arranged on both sides of the heat medium flow path 50 in the horizontal direction X. However, the specific arrangement of the heating elements 40 (pockets 21) may be any. For example, the heating elements 40 (pockets 21) may be arranged on only one side of the heat medium flow path 50 in the horizontal direction X. Alternatively, a plurality of heating elements 40 (pockets 21) may be arranged side by side in the flow path extension direction Z.

[0031] Furthermore, in the above-described embodiment, the housing 20 is formed as an integrally formed member, but the specific form of the housing 20 is not limited to being formed as an integral member. For example, the housing 20 may be formed by forming a portion of the peripheral wall of the pocket 21 that constitutes the pocket 21 separately, and attaching the portion of the housing 20 that was formed separately to the remaining housing 20.

[0032] DESCRIPTION OF SYMBOLS 10 Heat medium heater 20 Housing 20a Substrate facing surface 21 Pocket 21a Bottom surface 21b Inner surface 21c Inner surface 30 Substrate 40 Heat generating element 41 Housing 41a Lead protruding surface 42 Lead 50 Heat medium flow path 60 Heater 70 Fixing member 80 Insulating sheet 90 Heat dissipating filler X Horizontal direction Y Substrate vertical direction Z Flow path extending direction

Claims

1. A heat dissipation structure for a heat generating element, comprising a housing in which a heat generating element mounted on a substrate is placed, and which dissipates heat generated by the heat generating element to the housing, wherein the housing has an opening on its substrate-facing surface facing the substrate and a pocket recessed toward the side away from the substrate, and the heat generating element is placed in the pocket with its lead protruding surface facing the substrate.

2. The heat dissipation structure for a heating element according to claim 1, wherein the pocket is filled with a heat dissipation filler.

3. A heat transfer medium heater equipped with the heat dissipation structure of a heat generating element as described in claim 1, comprising a heat transfer medium flow path provided within the housing, and a heater for heating the heat transfer medium flowing through the heat transfer medium flow path, and the pocket is provided on the side of the heat transfer medium flow path in a lateral direction perpendicular to the substrate normal direction that is perpendicular to the substrate.

4. The heat transfer medium heater according to claim 3, characterized in that the pockets are provided on both sides of the heat transfer medium flow path in the lateral direction, and the heating elements are disposed in the respective pockets.

5. The heat transfer medium heater according to claim 3, further comprising a fixing member for fixing the heating element to the housing, the fixing member being arranged on the opposite side of the heat transfer medium flow path with the pocket in between in the lateral direction.

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