Electric control unit and assembling method thereof

Abstract

The invention discloses an electric control unit and an assembling method thereof. The electric control unit comprises a shell, the shell comprises a cover plate and a bottom plate, and the bottom plate is provided with a cooling side; and a force application element attached to the cover plate, the force application element being configured to act on the elastic sheet after the cover plate is mounted on the bottom plate to force the elastic sheet to deform so as to generate a pressure toward the cooling side on the plurality of chips through the second side of the chips. The chip is fully contacted with the cooling side of the shell, so that the heat of the chip can be effectively and reliably guided to the cooling side.

Description

Technical Field

[0001] The present application relates to an electronic control unit and also to a method for assembling the electronic control unit. Background Art

[0002] The electronic control unit (ECU) is a vehicle-mounted control device composed of integrated circuits. The ECU usually has a housing, in which a PCB is arranged. The electronic components on the PCB, such as power devices, generate heat when working. Power devices include various chips. There are multiple chips arranged in the ECU, so the heat generated is very large. The design of the ECU includes heat dissipation and insulation of the chips, as well as fixing these chips relative to the housing.

[0003] In the current technology, in order to dissipate heat, the chip is fastened to the housing of the electronic control unit by screws, or by a spring, which is also fixed by screws and pressed onto the chip under a certain pressure. The above method can make the chip contact with the housing, and the housing takes away the heat. Summary of the invention

[0004] One aspect of the present application is to provide an electric control unit, which guides heat away from the electric control unit in a different way from the prior art.

[0005] The electronic control unit includes a shell, the shell includes a cover plate and a base plate relative to the cover plate, the base plate having a cooling side; a PCB board, the PCB board is arranged in the shell and is located between the cover plate and the base plate; a chip holder, the chip holder is connected to the PCB board, the chip holder holds a plurality of chips connected to the PCB board, each of the chips has a first side and a second side opposite to each other, the cooling side faces the respective first sides of the plurality of chips; an elastic sheet, the elastic sheet is arranged at the second side of the plurality of chips; and a force-applying element attached to the cover plate, the force-applying element being constructed so that when the cover plate is mounted on the base plate, the force-applying element acts on the elastic sheet and then forces the elastic sheet to deform so as to generate pressure toward the cooling side on the plurality of chips through the second side.

[0006] In an embodiment of the electronic control unit, the force-applying element is a non-elastic support.

[0007] In an embodiment of the electronic control unit, the force-applying element is configured as a protrusion integrally formed with the cover plate, and the protrusion contacts the elastic sheet through a through hole on the PCB board.

[0008] In an embodiment of the electronic control unit, the elastic sheet includes a sheet body and a claw portion extending from the sheet body, and the claw portion is configured to press against a corresponding chip among the plurality of chips when a force is applied thereto.

[0009] In an embodiment of the electronic control unit, before the cover plate is mounted on the base plate, the first side of the chip held on the chip holder is not restricted in the force application direction, and the elastic sheet is pre-positioned to the chip holder in a plug-in manner.

[0010] In an embodiment of the electronic control unit, the chip holder is an injection-molded insulator, and the elastic sheet is formed by metal stamping.

[0011] In an embodiment of the electronic control unit, the PCB board is connected to the base plate by a plurality of screws; the cover plate is connected to the base plate by a plurality of screws; the chip is electrically connected to the PCB board; and the first side of the chip is in thermal contact with the cooling side.

[0012] In an embodiment of the electronic control unit, an insulating heat-conducting layer is arranged between the base plate and the cooling side.

[0013] In an embodiment of the electronic control unit, the electronic control unit is used for motor control.

[0014] By making the chip fully contact with the cooling side of the housing, the heat of the chip can be effectively and reliably directed to the cooling side. By using the fastening effect of the cover plate and the bottom plate to make the force-applying element act on the elastic sheet, the chip can be stably held in the housing with an elastic force of 20 to 100N during its service life. In addition, the use of screws is reduced, which in turn reduces costs, and the range of the prohibited area on the PCB board is reduced, which is helpful for PCB board design.

[0015] The force-applying element is applied to the elastic sheet. The restoring force generated by the deformation of the elastic sheet keeps the chip in contact with the shell on the one hand, and on the other hand, the cover plate is subjected to force through the force-applying element. In the prior art, screws are connected between the base plate and the chip or between the base plate and the elastic sheet, so the force-bearing party is the base plate. In contrast, the present application is subjected to force through the cover plate, which can reduce the stress on the base plate. In addition to transferring most of the heat of the chip to the cooling side, the force-applying element can also establish a new heat dissipation channel on the second side of the chip, so that the heat is transferred from the elastic sheet to the cover plate via the force-applying element.

[0016] Before the cover plate and the base plate are mounted, the chip is not fixed on the chip holder, and the first side of the chip has a certain degree of freedom, especially in the direction of force application. In the case of using multiple or multiple chips, or in the case of using multiple chip holders, the chip does not need to be mounted with high precision. After the cover plate and the base plate are mounted, the chip is pressed against the base plate, fixed relative to the base plate, and the first side is in full contact with the cooling side.

[0017] Another aspect of the present application is to provide a method for assembling an electronic control unit, wherein the electronic control unit includes a shell, and the shell further includes a cover plate and a base plate. The method includes: connecting a PCB board assembly to the base plate, the PCB board assembly including a PCB board, a plurality of chips mounted on the PCB board and a chip holder to hold the plurality of chips, and an elastic sheet mounted on the chip holder; and closing the cover plate and the base plate, a force-applying element attached to the cover plate acts on the elastic sheet and then forces the elastic sheet to deform so as to generate pressure on the cooling side of the base plate through the second side to the plurality of chips.

[0018] The electronic control unit of the present application achieves full contact between the chip and the shell during the installation of the cover plate and the base plate, thereby achieving the dual purposes of heat dissipation and fixation. This is different from most prior arts that fix the chip or elastic sheet, thus omitting multiple fixing steps.

[0019] Other aspects and features of the present application will become apparent from the following detailed description with reference to the accompanying drawings. It should be understood, however, that the drawings are designed for illustrative purposes only and are not intended to limit the scope of the present application, as reference should be made to the appended claims. It should also be understood that the drawings are intended only to conceptually illustrate the structures and processes described herein and, unless otherwise indicated, are not necessarily drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present application will be more fully understood by referring to the following detailed description of specific embodiments in conjunction with the accompanying drawings, in which the same reference numerals in the drawings always refer to the same elements in the drawings.

[0021] Figure 1 A cross-sectional view of an embodiment of an electronic control unit involved in the present application;

[0022] Figure 2 A simplified diagram of an embodiment of an elastic sheet arranged for a chip in an electronic control unit involved in the present application;

[0023] Figure 3 It is a simplified diagram of another embodiment of an elastic sheet arranged for a chip in an electronic control unit involved in the present application. DETAILED DESCRIPTION

[0024] In order to help those skilled in the art to accurately understand the subject matter for which protection is sought in the present application, the specific implementation of the present application is described in detail below in conjunction with the accompanying drawings.

[0025] Figure 11 is a cross-sectional view of an embodiment of an electric control unit involved in the present application. The electric control unit includes a housing 10, and the housing 10 further includes a cover plate 12 and a base plate 14 relative to the cover plate 12. A PCB board assembly is arranged in the housing 10, and the PCB board assembly includes a PCB board 20, a plurality of chips 40 connected to the PCB board 20, a chip holder 30 for holding the plurality of chips 40, and an elastic sheet 50. The PCB board 20 is arranged in the space of the housing 10 in a manner roughly parallel to the base plate 14, and is located between the cover plate 12 and the base plate 14. Here, for the sake of clarity, the upper cover plate 12 and the lower base plate 14 are distinguished, and the base plate 14 accommodates the PCB board assembly as the core component inside the electric control unit. However, the cover plate and the base plate are relative concepts. In other embodiments, the definitions of the cover plate and the base plate can be interchanged. The housing 10 is made of metal.

[0026] The PCB board 20 is electrically connected to the chip 40. In the cross section of the illustrated embodiment, there are two chips 40 connected to the PCB board in a plug-in form (THT, through-hole plug technology). The chip here refers to a packaged device or module. In one embodiment, the chip is a power device for switching, which generates a lot of heat during operation. In another embodiment, the chip is an IGBT chip. In yet another embodiment, the electronic control unit is used to control a three-phase motor, and two chips are a group responsible for one phase circuit. Therefore, a total of six chips are arranged in the housing, that is, three groups of chips are arranged side by side on the PCB board, such as Figure 2 As shown. Depending on the design of the PCB board, the number of chips can be more than six, such as twelve, or less than six, such as two. The arrangement of the chips is not limited to Figure 1-2 It can be a rectangular array, or a circular array or an irregular arrangement.

[0027] Each chip 40 has a first side 42 facing the base plate 14 and a second side 44 facing the PCB board 20. The surface of the first side 42 of the base plate 14 facing the chip 40 is the cooling side 16. The first side 42 is in thermal contact with the cooling side 16. The heat is guided to this side and transferred to the outside of the shell through the shell 10 to leave the shell 10. A heat sink can be arranged inside the shell 10 to directly conduct heat. In the illustrated embodiment, the heat sink is a heat-conducting layer 90 coated on the inside of the base plate 14. The heat-conducting layer 90 also has an insulating function. In other embodiments, the cooling side 16 of the base plate 14 is provided with a flow channel for cooling water or refrigerant to pass through. The chip holder 30 is connected between the chip 40 and the PCB board 20, and a certain distance is left between the second side 44 of the chip 40 and the PCB board 20 to facilitate heat dissipation. The chip holder 30 can be a single integral part used to hold all the chips 40 in the shell 10 so that Figure 2In the embodiment, for example, a chip holder can be provided to hold six chips. There can also be multiple chip holders 30, and any chip holder can hold one or a group of chips among the multiple chips. When the chip 40 is held on the chip holder 30, its second side 44 faces the PCB board 20.

[0028] The chip support 30 is an injection-molded insulator, including a first interface 32 connected to the chip 40, a second interface 34 connected to the PCB board 20, and a third interface 36 for connecting the chip 40 to the PCB board 20. Figure 1 As shown, the first interface 32 is a socket to receive and accommodate the chip 40. The second interface 34 is configured as a pin extending from the chip holder 30, and the pin is connected to the PCB board 20 in a plug-in manner. The third interface 36 is a through hole on the chip holder 30 to facilitate the pin of the chip 40 to pass through, and the through hole can be configured as an L-shape as shown in the figure, so as to receive the bent pin of the chip 40.

[0029] An elastic sheet 50 is also arranged at the second side 44 of the chip 40. The elastic sheet 50 is formed by stamping a metal with an elastic function. The elastic sheet 50 is pre-positioned on the chip holder 30. The chip holder 30 may further have a fourth interface (not shown in the figure) connected to the elastic sheet 50. The fourth interface may be a groove to receive the pin of the elastic sheet 50. In another embodiment, the elastic sheet can also be limited by designing the spacing between two parts on the chip holder 30, and the two parts are the corresponding chip holder parts where the two opposite chips are located.

[0030] The elastic sheet 50 includes a sheet body 52 and a claw portion 54 extending from the sheet body 52. ​​The claw portion 54 is configured to contact the second side 44 of the chip 40. The claw portion 54 may be a linear shape, such as Figure 1 As shown, the claw portion 54 may also be curved. The claw portion 54 is deformable, and the restoring force generated by the deformation can cause the claw portion 54 to provide pressure to the chip 40. Figure 2 In the illustrated embodiment, the elastic sheet 50 is a single integral piece. The elastic sheet 50 may also include a plurality of elastic sheets, such as Figure 3 As shown, the integrated elastic sheet is replaced by three elastic sheets, wherein any one of the elastic sheets provides pressure for a group of chips relative to each other.

[0031] The cover plate 12 is attached with a force applying element 60. The force applying element 60 is configured such that after the cover plate 12 and the base plate 14 are installed, the force applying element 60 acts on the elastic sheet 50, such as Figure 1As shown by the arrow in the middle, the elastic sheet 50 is then forced to deform to generate pressure on the chip 40 toward the cooling side 16 through the second side 44. When the cover plate 12 and the base plate 14 are installed in place and fixed, the force-applying element 60 provides a stable supporting force to ensure that the elastic sheet 50 presses the chip 40 toward the cooling side 16 of the housing 10 to obtain sufficient contact between the chip 40 and the housing 10. The force-applying element 60 is non-elastic, such as Figure 1 As shown, the force-applying element 60 is a solid piece and plays a supporting role, and it can be constructed as a protrusion integrally formed with the cover body 12. Correspondingly, the PCB board 20 is provided with a through hole 22 so that the protrusion passes through the PCB board 20 so as to contact the sheet body 52 of the elastic sheet 50 when the cover board 12 is installed. Further, the protrusion is a strip-shaped piece with a certain length, or there are multiple protrusions to correspond to multiple elastic sheets. Furthermore, the shape of the protrusion can be designed to be rectangular, circular, elliptical, etc.

[0032] The PCB board 20 is connected to the bottom plate by a plurality of screws 70. The cover plate 12 is connected to the bottom plate 14 by a plurality of screws 80.

[0033] The process of assembling the shell of the electronic control unit is as follows. First, assemble the PCB board assembly. Pre-install the pins of the chip holder 30 on the PCB board 20, and insert the chip 40 into the chip holder 30, and the pins of the chip 40 pass through the chip holder 30. The second interface 34 and the optional fourth interface of the chip holder 30 both provide transition fit. The components are pre-installed, including between the chip 40 and the chip holder 30, and between the elastic sheet 50 and the chip holder 30. The chip 40 can move slightly in the chip holder 30, and its first side 42 is not restricted in the direction perpendicular to the PCB board. Then pre-position the elastic sheet 50 on the chip holder 30. Finally, weld 48 the pins of the chip 40. The PCB board 20, the chip 40, the chip holder 30 and the elastic sheet 50 are connected together to form a PCB board assembly.

[0034] The PCB board assembly is placed in the bottom plate 14 and fixed by screws 70. Then the cover plate 12 is installed on the bottom plate 14, and the force-applying element 60 presses on the elastic sheet 50, so that the elastic sheet 50 is deformed and generates a force to press the chip 40 to the cooling side 16 of the housing 10. The cover plate 12 is fixed to the bottom plate 14 by screws 80. The housing 10 is assembled. At this time, the chip 40 in the housing 10 is retained in the housing 10 due to the existence of elastic force, and the first side 42 is fully in contact with the cooling side 16, and the elastic sheet 50 is retained between the force-applying element 60 and the chip 40.

[0035] The electric control unit can be used to control the motor. The housing of the electric control unit involved in the present application can be integrated with or separated from the housing of the motor.

[0036] Although specific embodiments of the present application have been shown and described in detail to illustrate the principles of the present application, it should be understood that the present application can be implemented in other ways without departing from such principles.

Claims

1. An electronic control unit, characterized in that include: A housing (10), the housing (10) comprising a cover plate (12) and a bottom plate (14) opposite to the cover plate (12), the bottom plate (14) having a cooling side (16); A PCB board (20), the PCB board (20) being arranged in the housing (10) and located between the cover plate (12) and the bottom plate (14); a chip holder (30), the chip holder (30) being connected to the PCB board (20), the chip holder (30) holding a plurality of chips (40) connected to the PCB board (20), each chip (40) having a first side (42) and a second side (44) opposite to each other, the cooling side (16) facing the respective first sides (42) of the plurality of chips (40); an elastic sheet (50) arranged at the second side (44) of the plurality of chips (40); and A force-applying element (60) is attached to the cover plate (12), and the force-applying element (60) is constructed so that when the cover plate (12) is mounted on the base plate (14), the force-applying element (60) acts on the elastic sheet (50) and then forces the elastic sheet (50) to deform so as to generate pressure toward the cooling side (16) on the plurality of chips (40) through the second side (44).

2. The electronic control unit according to claim 1, characterized in that: The force applying element (60) is a non-elastic supporting member.

3. The electronic control unit according to claim 1, characterized in that: The force-applying element (60) is constructed as a protrusion integrally formed with the cover plate (12), and the protrusion contacts the elastic sheet (50) through a through hole (22) on the PCB board (20).

4. The electronic control unit according to claim 1, characterized in that: The elastic sheet (50) comprises a sheet body (52) and a claw portion (54) extending from the sheet body (52), wherein the claw portion (54) is configured to press against a corresponding chip among the plurality of chips (40) when a force is applied thereto.

5. The electronic control unit according to claim 1, characterized in that: Before the cover plate (12) is mounted on the base plate (14), the first side (42) of the chip (40) held on the chip holder (30) is not restricted in the force application direction, and the elastic sheet (50) is pre-positioned to the chip holder (30) in a plug-in manner.

6. The electronic control unit according to claim 1, characterized in that: The chip support (30) is an injection-molded insulator, and the elastic sheet (50) is formed by metal stamping.

7. The electronic control unit according to claim 1, characterized in that: The PCB board (20) is connected to the base board (14) via a plurality of screws (70); the cover board (14) is connected to the base board (14) via a plurality of screws (80); the chip (40) is electrically connected to the PCB board (20); The first side (42) of the chip (40) is in thermal contact with the cooling side (16).

8. The electronic control unit according to claim 1 is characterized in that: An insulating heat-conducting layer (90) is arranged between the cooling side (16) and the first side (42) of the base plate (14).

9. The electronic control unit according to any one of claims 1 to 8, characterized in that: The electronic control unit is used for motor control.

10. A method for assembling an electronic control unit, characterized in that The electronic control unit comprises a housing (10), the housing (10) further comprising a cover plate (12) and a bottom plate (14), and the method comprises: Connecting a PCB board assembly to the base plate (14), the PCB board assembly comprising a PCB board (20), a plurality of chips (40) mounted on the PCB board (20) and a chip holder (30), and an elastic sheet (50) mounted on the chip holder (30), the chip holder (30) holding the plurality of chips (40); and The cover plate (12) and the base plate (14) are closed, and a force-applying element (60) attached to the cover plate (12) acts on the elastic sheet (50) and forces the elastic sheet (50) to deform so as to generate pressure on the plurality of chips (40) toward the cooling side (16) of the base plate (14).

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