Electronic device, method for assembling an electronic device, and inverter device

Abstract

The present invention provides an electronic device, a method for assembling an electronic device, and an inverter device that can suppress an increase in the number of parts. [Solution] An electronic device according to one embodiment comprises a heating element, a heat sink, a substrate, and a fixing member. The heat sink dissipates the heat generated from the heating element. The substrate is connected to the heating element via lead pins. The fixing member is integrally formed with a substrate fixing portion to which the substrate is fixed and a leaf spring portion that presses and fixes the heating element to the heat sink.

Description

Technical Field

[0001] The disclosed embodiments relate to an electronic device, an assembling method of an electronic device, and an inverter device.

Background Art

[0002] Conventionally, electronic devices such as inverter devices and DCDC converter devices include switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and MOS-FETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The switching element is a heat-generating element. In the case of a type in which such a heat-generating element is surface-mounted on a substrate, the heat-generating element is often dissipated through the substrate. On the other hand, in the case of a type in which the heat-generating element is connected to the substrate via lead pins, the heat-generating element is often fixed to a heat sink for heat dissipation. Therefore, a technique of pressing and fixing the heat-generating element to the heat sink with a leaf spring member has been proposed (see, for example, Patent Document 1). Further, in the prior art, the substrate is fixed using a substrate fixing member such as a boss.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art, since it is necessary to separately prepare the leaf spring member and the substrate fixing member, there is a problem that the number of parts increases.

[0005] One aspect of the embodiment is made in view of the above, and an object thereof is to provide an electronic device, an assembling method of an electronic device, and an inverter device capable of suppressing an increase in the number of parts. [Means for solving the problem]

[0006] To solve the above problems and achieve the objective, an electronic device according to one embodiment comprises a heating element, a heat sink, a substrate, and a fixing member. The heat sink dissipates the heat generated from the heating element. The substrate is connected to the heating element via lead pins. The fixing member is integrally formed with a substrate fixing portion to which the substrate is fixed and a leaf spring portion that presses and fixes the heating element to the heat sink. [Effects of the Invention]

[0007] In one embodiment, the electronic device is provided with a fixing member in which a substrate fixing portion to which a substrate is fixed and a leaf spring portion to which a heating element is pressed and fixed to a heat sink are integrally formed. By providing such a fixing member, it is not necessary to prepare the leaf spring portion and the substrate fixing portion separately, and thus the increase in the number of components in the electronic device can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of an inverter device according to an embodiment. [Figure 2] Figure 2 is an exploded perspective view of the inverter device. [Figure 3] Figure 3 is a plan view of the inverter device. [Figure 4] Figure 4 is an end view of line IV-IV in Figure 3. [Figure 5] Figure 5 is an end view of the VV line in Figure 3. [Figure 6] Figure 6 is a flowchart showing an example of the assembly procedure for an inverter device. [Modes for carrying out the invention]

[0009] The embodiments of the electronic device, the method for assembling the electronic device, and the inverter device disclosed herein will be described in detail below with reference to the attached drawings. However, the present invention is not limited to the embodiments described below.

[0010] In the following description, the example of an electronic device in this embodiment is an inverter device. That is, the inverter device in this embodiment is an example of an electronic device. Note that the electronic device is not limited to an inverter device, and may be other types of devices such as a DC-DC converter device.

[0011] Figure 1 is a perspective view of an inverter device 1 according to an embodiment. Note that Figure 1 and the subsequent figures shown later (Figure 2 and beyond) are schematic diagrams. Also, in Figure 1, the case of the inverter device 1 is omitted for the sake of simplicity. Furthermore, in Figure 1, for the sake of ease of understanding, a three-dimensional Cartesian coordinate system is shown, defined by mutually orthogonal X-axis, Y-axis, and Z-axis directions. Such a Cartesian coordinate system may also be shown in other drawings used in the explanations below. Moreover, the Cartesian coordinate system is the X-axis, Y-axis, and Z-axis directions when the inverter device 1 is in the illustrated state, and does not limit the mounting direction or arrangement direction of the inverter device 1.

[0012] The inverter device 1 shown in Figure 1 is connected to a motor (not shown) that serves as a power source for, for example, an electric vehicle or a hybrid vehicle, and supplies power to such a motor. Specifically, the inverter device 1 comprises a plurality (specifically three) inverter units 10. Each of the plurality of inverter units 10 comprises a first busbar 11 and a second busbar 12. A battery (not shown) is connected to the first busbar 11. A motor is connected to the second busbar 12.

[0013] The inverter device 1 converts DC power from the battery into AC power and outputs it to the motor. Specifically, one of the U-phase, V-phase, and W-phase coils of the corresponding motor is connected to the second busbar 12. The inverter device 1 converts the DC power input from the battery via the first busbar 11 into three-phase AC power and outputs it to the motor via the second busbar 12. Depending on the configuration of the inverter device 1, two of the U-phase, V-phase, and W-phase coils of the corresponding motor may be connected to the second busbar 12.

[0014] Next, the configuration of the inverter device 1 will be explained in detail with reference to Figure 2 and subsequent figures. Note that the following explanation will use one of the three inverter units 10 in the inverter device 1, but since the three inverter units 10 have substantially the same configuration, the following explanation is generally applicable to the other two inverter units 10 as well.

[0015] Figure 2 is an exploded perspective view of the inverter device 1. As shown in Figure 2, the inverter device 1 (inverter unit 10) comprises the first and second busbars 11 and 12, heat sink 20, capacitor 30, heat dissipation sheet 40, power element 50, fixing member 60, and substrate 70.

[0016] The heat sink 20 is a heat dissipation component that dissipates heat generated from the power element 50. The heat sink 20 is formed in a roughly rectangular parallelepiped shape. Heat dissipation fins 21 are formed on the lower side of the heat sink 20. The main surface (top surface) 20a of the heat sink 20 is formed to be flat, and the power element 50 is fixed to this main surface 20a. Screw holes 22 for attaching the fixing member 60 are formed on the side surface 20b of the heat sink 20. The power element 50 is fixed to the heat sink 20 by the fixing member 60, which will be explained in detail later.

[0017] The capacitor 30 is connected to a battery (not shown) via the first bus bar 11. The capacitor 30 smoothes, for example, the voltage of the battery. The heat dissipation sheet 40 is a heat dissipation and insulating member inserted between the heat sink 20 and the power element 50. The heat dissipation sheet 40 has relatively high thermal conductivity while insulating the heat sink 20 and the power element 50, and efficiently transfers the heat generated from the power element 50 to the heat sink 20.

[0018] The power element 50 is a switching element. The power element 50 is, for example, an IGBT. Note that the power element 50 is not limited to an IGBT, and may be other types of switching elements such as a MOS-FET. Further, since the power element 50 generates heat during operation or the like, it is a heat generating element. That is, the power element 50 is an example of a heat generating element. Note that the heat generating element is not limited to the power element 50, and may be other types of elements as long as they generate heat.

[0019] Here, the power element 50 will be described while also referring to FIG. 3. FIG. 3 is a plan view of the inverter device 1 (inverter unit 10). In FIG. 3, for convenience of understanding, the substrate 70 is shown by a dashed line, and the description of the first and second bus bars 11, 12, etc. is omitted.

[0020] As shown in FIGS. 2 and 3, the power element 50 includes lead pins 51. The lead pins 51 are formed to extend toward the substrate 7 that is arranged above. The power element 50 is connected to the substrate 70 via the lead pins 51. Specifically, the power element 50 is electrically connected to the substrate 70 when the lead pins 51 are inserted into the connection holes 71 (see FIG. 2) of the substrate 70.

[0021] There are a plurality (specifically, 10) of power elements 50. As shown well in FIG. 3, the plurality of power elements 50 are arranged in two columns at positions facing each other. Specifically, 5 power elements 50 are arranged in a column along the Y-axis direction, and such columns are arranged in parallel in the X-axis direction. More specifically, the plurality of power elements 50 are arranged to form a column of high-side power elements 50 and a column of low-side power elements 50. Also, the plurality of power elements 50 are arranged such that their lead pins 51 face each other. By arranging them in two columns such that their lead pins 51 face each other, the distance a (see FIG. 3) between the power elements 50 can be made as short as possible. By shortening the distance a between the power elements 50, it becomes possible to reduce the parasitic inductance, and thus the surge voltage generated by switching in the inverter device 1 can be reduced.

[0022] The substrate 70 is a circuit board on which a circuit for controlling the power element 50 and the like are mounted. As shown in FIG. 2, connection holes 71 and through holes 72 are formed in the substrate 70. There are a plurality of connection holes 71, such as through holes, vias, etc. The plurality of connection holes 71 include holes electrically connected to the lead pins 51 of the power element 50. Also, the plurality of connection holes 71 include holes electrically connected to the first and second bus bars 11, 12.

[0023] The through hole 72 is a hole through which a screw 80 (see FIG. ३) for fixing the substrate is inserted. There are a plurality (for example, 4) of through holes 72, which are formed, for example, at the four corners of the substrate 70. Note that the position, number, etc. of the through holes 72 are merely examples and are not limited.

[0024] The fixing member 60 is a member for fixing the substrate 70 and the power elements 50. The fixing member 60 is made from a metal material or the like, but is not limited to this. There are multiple fixing members 60 (for example, two). One fixing member 60 can fix multiple power elements 50 (for example, five power elements 50 arranged in a row), but the number of power elements 50 that can be fixed is not limited to this. Also, in this example, two fixing members 60 are used to fix the substrate 70, but the number of fixing members 60 is not limited to this.

[0025] The fixing member 60 comprises a substrate fixing portion 61, a leaf spring portion 62, and a connecting portion 63, and is attached to the heat sink 20. The substrate fixing portion 61, the leaf spring portion 62, and the connecting portion 63 are integrally formed. Specifically, the substrate fixing portion 61 is formed to be located at both ends in the longitudinal direction of the fixing member 60. The leaf spring portion 62 is formed to be located between the substrate fixing portions 61 at both ends. The connecting portion 63 is formed to connect the substrate fixing portion 61 and the leaf spring portion 62. The substrate fixing portion 61, the leaf spring portion 62, and the connecting portion 63 will be described in detail below.

[0026] The substrate fixing portion 61 is the part to which the substrate 70 is fixed. Here, the substrate fixing portion 61 will be explained with reference to Figure 4. Figure 4 is an end view of line IV-IV in Figure 3.

[0027] As shown in Figure 4, the substrate fixing portion 61 comprises a base portion 61a and a fixing portion 61b. The base portion 61a is flat and is formed to extend upward along the Z-axis. The fixing portion 61b is flat and is formed to extend horizontally (in the X-axis direction) from the end of the base portion 61a on the Z-axis side. The fixing portion 61b is located below the substrate 70 and corresponds to the insertion hole 72 of the substrate 70. A screw hole 61c is formed in the fixing portion 61b at a position corresponding to the insertion hole 72 of the substrate 70. Therefore, the substrate 70 is fixed to the substrate fixing portion 61 by inserting the screws 80 for fixing the substrate through the insertion hole 72 of the substrate 70 and the screw hole 61c of the substrate fixing portion 61 (more precisely, the fixing portion 61b) and fastening them.

[0028] Continuing the explanation of Figures 2 and 3, the leaf spring portion 62 is the part that presses and fixes the power element 50 to the heat sink 20. Now, the leaf spring portion 62 will be explained with reference to Figure 5. Figure 5 is a VV line end view of Figure 3.

[0029] As shown in Figure 5, multiple leaf spring portions 62 are formed between the substrate fixing portions 61 on both ends of the fixing member 60 (specifically, five portions). Each leaf spring portion 62 comprises a base portion 62a, an extended portion 62b, and a bent portion 62c. The base portion 62a, extended portion 62b, and bent portion 62c are all flat plates. The base portion 62a is formed to extend upward along the Z-axis. The extended portion 62b is formed to extend from the end of the base portion 62a on the Z-axis side toward the power element 50. The bent portion 62c extends from the end of the extended portion 62b toward the power element 50 and is formed to bend. The bent portion 62c presses the upper surface 50a of the power element 50 toward the heat sink 20 with its convex portion, fixing the power element 50 to the heat sink 20. In other words, the leaf spring portion 62 is an elastic body that uses elastic force to press and fix the power element 50 to the heat sink 20.

[0030] Continuing the explanation of Figures 2 and 3, the connecting portion 63 is flat. The connecting portion 63 has substrate fixing portions 61 continuously formed at each end, and a leaf spring portion 62 continuously formed in the position between the substrate fixing portions 61 at both ends. In this way, the connecting portion 63 is formed so that the substrate fixing portions 61 and the leaf spring portion 62 are continuous, and thus connects the substrate fixing portions 61 and the leaf spring portion 62.

[0031] The connecting portion 63 is formed to extend along the Y-axis. In other words, the connecting portion 63 is formed to extend along the side surface 20b of the heat sink 20 (see Figure 2; not visible in Figure 3). Furthermore, the connecting portion 63 is positioned to cover a portion of the side surface 20b of the heat sink 20. Alternatively, the connecting portion 63 may be positioned to cover the entire side surface 20b of the heat sink 20.

[0032] As shown in Figures 2 and 4, the connecting portion 63 is provided with an insertion hole 63a. The insertion hole 63a is a hole through which a screw 81 (see Figure 4) for attaching the fixing member 60 is inserted. The insertion hole 63a is formed in the connecting portion 63 at a position corresponding to the screw hole 22 on the side surface 20b of the heat sink 20. Therefore, the fixing member 60 is attached (fixed) to the heat sink 20 by inserting the screw 81 through the insertion hole 63a of the fixing member 60 (more precisely, the connecting portion 63) and the screw hole 22 on the side surface 20b of the heat sink 20 and fastening it.

[0033] Next, the assembly procedure for the inverter device 1 configured as described above will be explained with reference to Figure 6. Figure 6 is a flowchart showing an example of the assembly procedure for the inverter device 1. Note that the assembly procedure shown in Figure 6 is performed by, for example, a robot (not shown), a worker, etc.

[0034] As shown in Figure 6, the robot first aligns the power elements 50 (step S10). Specifically, the robot sets multiple power elements 50 in an alignment jig (not shown) and aligns them so that they form two rows facing each other.

[0035] Next, the robot places the power elements 50 onto the heat sink 20 (step S11). Specifically, the robot places the aligned power elements 50 onto the main surface 20a of the heat sink 20 via the heat dissipation sheet 40.

[0036] Next, the work robot or the like uses the leaf spring portion 62 of the fixing member 60 to fix the power element 50 to the heat sink 20 (step S12). Specifically, the work robot or the like brings the leaf spring portion 62 of the fixing member 60 into contact with the upper surface 50a of the power element 50, and presses the power element 50 to the heat sink 20 with the leaf spring portion 62 to fix it in place (pressing step).

[0037] Next, the work robot fastens the fixing member 60 to the heat sink 20 (step S13). Specifically, with the leaf spring portion 62 pressing against the power element 50 in step S12, the work robot fastens the fixing member 60 to the heat sink 20 by inserting the screw 81 through the insertion hole 63a of the fixing member 60 and the screw hole 22 on the side surface 20b of the heat sink 20 and fastening it.

[0038] Next, the robot attaches the first and second busbars 11 and 12 to the substrate 70 (step S14). Then, the robot fixes the substrate 70, with the first and second busbars 11 and 12 attached, to the substrate fixing portion 61 of the fixing member 60 (step S15). Specifically, the robot places the substrate 70 on the fixing portion 61b of the substrate fixing portion 61. With the substrate 70 in place, the lead pins 51 of the power element 50 are inserted into the connection holes 71 of the substrate 70. The robot then fixes (installs) the substrate 70 to the substrate fixing portion 61 by inserting screws 80 through the insertion holes 72 of the substrate 70 and the screw holes 61c of the fixing portion 61b of the substrate fixing portion 61 and fastening them. In this way, after the pressing step, an installation step is performed to fix the substrate 70 to the substrate fixing portion 61 of the fixing member 60.

[0039] Next, the robot performs soldering (step S16). Specifically, the robot solders the lead pins 51 of the power element 50 to the connection holes 71 of the circuit board 70, electrically connecting the power element 50 and the circuit board 70. Similarly, the robot solders the first and second busbars 11 and 12 to the connection holes 71 of the circuit board 70, electrically connecting the first and second busbars 11 and 12 to the circuit board 70.

[0040] As described above, the inverter device 1 according to this embodiment comprises a power element (an example of a heat-generating element) 50, a heat sink 20, a substrate 70, and a fixing member 60. The heat sink 20 dissipates the heat generated from the power element 50. The substrate 70 is connected to the power element 50 via lead pins 51. The fixing member 60 is integrally formed with a substrate fixing portion 61 to which the substrate 70 is fixed and a leaf spring portion 62 that presses and fixes the power element 50 to the heat sink 20.

[0041] Thus, the inverter device 1 is equipped with a fixing member 60 in which a substrate fixing part 61 to which the substrate 70 is fixed and a leaf spring part 62 that presses and fixes the power element 50 to the heat sink 20 are integrally formed. By providing such a fixing member 60, it is not necessary to prepare the leaf spring part and the substrate fixing part separately, and thus the increase in the number of parts in the inverter device 1 can be suppressed.

[0042] Furthermore, the fixing member 60 is attached to the heat sink 20. As a result, even when the fixing member 60 according to this embodiment is provided, there is no need to provide a new member to which the fixing member 60 is attached, and as a result, the increase in the number of parts in the inverter device 1 can be further suppressed.

[0043] Furthermore, the fixing member 60 is attached to the side surface 20b of the heat sink 20 to which the power element 50 is fixed on the main surface 20a. This makes it possible to miniaturize the inverter device 1. That is, for example, if the leaf spring part is configured to be attached to the main surface 20a of the power element 50, the leaf spring part will require a mounting part to attach to the main surface 20a, and the inverter device 1 may become larger in the width direction (X-axis direction) by the amount of that mounting part. In contrast, since the fixing member 60 according to this embodiment is attached to the side surface 20b of the heat sink 20, the above-mentioned mounting part can be eliminated, and thus the inverter device 1 can be made smaller in the width direction (X-axis direction).

[0044] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0045] 1. Inverter device 20 Heatsinks 50 Power Elements 51 Lead pins 60 Fixing member 61 Substrate fixing part 62 Leaf spring section 70 circuit boards

Claims

1. Heating element and A heat sink that dissipates the heat generated from the aforementioned heat-generating element, A substrate connected to the aforementioned heating element via lead pins, A fixing member is formed integrally with a substrate fixing portion to which the substrate is fixed and a leaf spring portion that presses and fixes the heating element to the heat sink. An electronic device equipped with the following features.

2. There are multiple heating elements, The multiple heating elements are arranged in two rows facing each other. The electronic device according to claim 1.

3. The aforementioned fixing member is The heat sink is attached to the aforementioned heat sink. The electronic device according to claim 1.

4. The aforementioned fixing member is The heating element is attached to the side surface of the heat sink, which is fixed to the main surface. The electronic device according to claim 3.

5. A method for assembling an electronic device comprising a heating element, a heat sink for dissipating heat generated from the heating element, a substrate connected to the heating element via lead pins, and a fixing member integrally formed with a substrate fixing portion for fixing the substrate and a leaf spring portion for pressing and fixing the heating element to the heat sink, The pressing step involves pressing the heating element against the heat sink using the leaf spring portion of the fixing member, After the pressing step, an installation step is performed to fix the substrate to the substrate fixing portion of the fixing member. A method for assembling an electronic device, including the assembly of an electronic device.

6. An inverter device comprising multiple inverter units that convert DC power to AC power through the operation of power elements, The inverter unit is The aforementioned power element, A heat sink for dissipating heat generated from the power element, A circuit board connected to the aforementioned power element via lead pins, A fixing member is formed integrally with a substrate fixing portion to which the substrate is fixed and a leaf spring portion that presses and fixes the power element to the heat sink. Equipped with, Inverter device.

Images