Electronic control unit

Abstract

To provide an electronic control unit capable of shortening assembly time by energizing a semiconductor to a cooling base plate, using only a little number of components.SOLUTION: An electronic control unit (1) for an electrical apparatus of an electric drive system includes: at least one semiconductor board (2) having a plurality of power semiconductors (3); a base plate (4) for diffusing the heat generated at the electronic control unit (1); a holding bracket (6) mounted on the base plate (4); and elastic energization means (8) arranged between the holding bracket (6) and the plurality of power semiconductors (3) to energize the power conductor (3) to the base plate (4), and the holding bracket (6) includes means for mounting the elastic energization means (8) to the holding bracket.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The invention relates to an electronic control unit according to the preamble of independent claim 1.

[0002] Background technology It is commonly known to bias a heat-generating semiconductor package of an electronic control device toward a heat sink in order to effectively dissipate heat from the semiconductor device through the heat sink.

[0003] A known prior art electronic control device is disclosed in Korean Patent Publication No. 2008-0099111. It describes a box-shaped housing with openings on both sides and an aluminum heat sink attached to one opening of the housing. A semiconductor switching element of the electronic control device is disposed in the housing and is pressed against the heat sink via a leaf spring that is attached to the heat sink by a screw.

[0004] A means for clamping a semiconductor to a heat sink is also disclosed in US Patent No. 5,483,103. Again, a leaf spring is attached to the heat sink by a screw and the leaf spring urges the semiconductor, in this case via a leveller, towards the heat sink.

[0005] An electronic power inverter for an electric machine is also known from EP 3609066. The power inverter has a housing with a semiconductor board, a capacitor board, power terminals and phase terminal studs. The semiconductor boat is biased towards the heat exchanger by a hold-down plate which is attached to the heat exchanger plate by screws, whereby a busbar guide plate, a capacity plate and a damping plate are located between the semiconductor boat and the hold-down plate.

[0006] overview The electrical control unit according to the invention, as defined in claim 1, has the advantage that only a small number of components can be used to urge the semiconductor towards the cooling base plate, reducing assembly time.

[0007] This object is achieved according to the invention by an electronic control unit for an electric machine, the electronic control unit having at least one semiconductor board having a plurality of power semiconductors, a base plate for dissipating heat generated in the electronic control unit, a holding bracket attached to the base plate, and resilient biasing means arranged between the holding bracket and the plurality of power semiconductors for biasing the power semiconductors towards the base plate, the holding bracket having means for attaching the resilient biasing means to the holding bracket.

[0008] By providing the retaining bracket with means for mounting the resilient biasing means, it is not necessary to attach the respective springs, which press the power semiconductors against the base plate, to the cooling base plate by means of screws, thus reducing the number of parts and improving assembly time, and also saving space compared to prior art designs in which the respective springs are attached to the base plate by means of screws.

[0009] The electronic control unit may in particular be a power inverter.

[0010] The resilient biasing means are advantageously constituted by a number of leaf springs which are thus mounted on a retaining bracket which is attached to the base plate, each of the leaf springs having a central fixed part for mounting the leaf spring on the retaining bracket and a number of biasing arms which extend integrally from the central fixed part and are in contact with one of the power semiconductors or the semiconductor board for biasing the power semiconductor towards the base plate.

[0011] Since the power semiconductors are arranged on the semiconductor board, in the first embodiment these power semiconductors are not in direct contact with the base plate, however, pressing the power semiconductors in turn presses the semiconductor board against the base plate and the contact between the power semiconductors, the semiconductor board and the base plate is good, especially in the region of the power semiconductors which generate heat, due to the leaf springs pressing against the power semiconductors.

[0012] In an alternative embodiment, the power semiconductors can be arranged on the side of the semiconductor board facing the base plate, whereby the leaf springs can be arranged in contact with the semiconductor board in the area of ​​the power semiconductors, the power semiconductors being in direct contact with the heat dissipating base plate.

[0013] The leaf springs are preferably formed from sheet metal.

[0014] In a preferred embodiment, each leaf spring has at least four biasing arms that extend integrally from a central fixed portion and each contact one of the power semiconductors or the semiconductor board to bias the power semiconductors toward the base plate. The leaf springs are preferably stamped from a single piece of sheet metal. In this way, each leaf spring can bias four power semiconductors toward the base plate, thereby reducing the number of parts required.

[0015] The leaf springs can have at least one fixing opening in the central fixing portion. Preferably, two fixing openings are provided in each leaf spring. By providing two fixing openings, the leaf springs can be positioned with respect to the retaining bracket so that they cannot rotate relative to the retaining bracket.

[0016] The means for attaching the resilient biasing means to the retaining bracket comprises a retaining pin protruding from the retaining bracket. Advantageously, the retaining bracket and the retaining pin can be molded as one piece. The retaining pin, which is integral with the retaining bracket, is preferably formed from aluminum, for example by die casting. Alternatively, the retaining pin, which is integral with the retaining bracket, can be formed from plastic to reduce weight, in which case the retaining bracket can be formed by injection molding. Thus, in order to reduce assembly time, the retaining pin and the retaining bracket can be manufactured in one molding step.

[0017] The retaining pin extends through a corresponding fastening opening in the leaf spring, which is attached to the retaining bracket by deformation of the retaining pin. The end of the retaining pin is preferably deformed so that the leaf spring is not rigidly fixed to the retaining bracket, but rather is fixed in a floating manner. This has the advantage that the pin is not overstrained when applying a biasing force to the semiconductor, and the spring can position itself accurately in the retaining bracket.

[0018] The retaining bracket is attached to the base plate by means of a number of screws. For this purpose, the retaining bracket can have a number of through holes, through which the screws extend. The retaining bracket can be attached to the base plate by means of the screws, which can be located at an edge or a corner of the bracket, away from the power semiconductors. The fixing screws of the retaining bracket are thus not located between the power semiconductors. In this way, the electronic control unit can be made more compact.

[0019] The holding bracket is provided with at least one, preferably at least two, locating holes for respectively accommodating a plurality of first locating pins fixed or accommodated in the base plate. The first locating pins may also extend through the locating holes in the at least one semiconductor board. Thus, the holding bracket can be accurately positioned relative to the base plate and / or the at least one semiconductor board.

[0020] The retainer bracket has a plurality of second locating pins for locating the logic control board relative to the retainer bracket. The pins can be made of metal, preferably steel. The second locating pins extend from the retainer bracket in a direction away from the base plate.

[0021] The base plate is formed from a thermally conductive metal, preferably aluminum, and may have pins or fins to improve heat dissipation.

[0022] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a perspective view of an electronic control unit according to the present invention; [Diagram 2] FIG. 2 is an exploded view of the electronic control unit of FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view of an electronic control unit according to the present invention. [Figure 4] FIG. 2 is a bottom perspective view of a retainer bracket according to the present invention; [Diagram 5] FIG. 2 is a top perspective view of a retaining bracket according to the present invention; [Figure 6] FIG. 1 is a perspective view of a leaf spring according to the present invention. [Figure 7] FIG. 13 is a cross-sectional view of a member of the retainer bracket.

[0024] Detailed Description In figures 1 and 2 an electronic control unit 1 for an electric machine according to the invention is shown. In figure 2 an exploded view of the electronic control unit 1 is shown. The electronic control unit 1 may for example be an inverter unit for supplying a three-phase power to an electric motor. It may also be a converter unit for converting the three-phase power from a generator motor into DC power.

[0025] The electronic control unit 1 comprises at least one semiconductor board 2 with a number of power semiconductors 3. The power semiconductors generate heat when switching, which must be dissipated. For this purpose, a base plate 4 is provided for dissipating the heat generated in the electronic control unit. The base plate 4 is preferably made of aluminum and may have a number of pins or fins 5 to improve cooling.

[0026] The retaining bracket 6 is attached to the base plate 4 via screws 7. Resilient biasing means in the form of leaf springs 8 are arranged between the retaining bracket 6 and the plurality of power semiconductors 3 for biasing the power semiconductors 3 towards the base plate, and the retaining bracket 6 has means 9 for attaching the resilient biasing means 8 to the retaining bracket 6.

[0027] By providing the holding bracket 6 with means 9 for attaching the leaf springs 8, it is no longer necessary to attach the respective springs, which press the power semiconductors against the base plate, to the cooling base plate by means of screws.

[0028] As can be best seen in Figures 3 and 6, each leaf spring 8 has a central fixed portion 10 for mounting the leaf spring 8 to the retaining bracket 6 and a plurality of biasing arms 11 extending integrally from the central fixed portion 10 and in contact with one of the power semiconductors 3 or the semiconductor board 2 to bias the plurality of power semiconductors 3 towards the base plate 4.

[0029] In the embodiment shown, the power semiconductors 3 are arranged on the side of the semiconductor board 2 facing away from the base plate 4, so that the power semiconductors 3 are not in direct contact with the base plate 4, but the pressing of the semiconductors in turn presses the semiconductor board 2 against the base plate 4, and the contact between the power semiconductors 3, the semiconductor board 2 and the base plate 4 is improved in the region of the heat-generating power semiconductors 3. In order to improve the heat conduction from the semiconductors 3, the base plate 4 may also be provided with a heat-conducting layer in the region of the semiconductor board 2.

[0030] In an alternative embodiment, the power semiconductors 3 can be arranged on the side of the semiconductor board facing the base plate 4, whereby the leaf springs 8 are then arranged in contact with the semiconductor board 2 in the area of ​​the power semiconductors and the power semiconductors 3 are then in direct contact with the heat dissipating base plate 4.

[0031] The leaf springs 8 are preferably made of sheet metal, preferably stamped from a single piece of metal. In the illustrated embodiment, the leaf springs 8 each have four biasing arms 11 extending integrally from the central fixed portion 10 and each contacting one of the semiconductors 3 to bias the semiconductors 3 towards the base plate 4. Each leaf spring 8 thus presses four power semiconductors 3 towards the base plate 4, thus reducing the number of components required. For the full-bridge inverter with 12 power semiconductors 3 shown in Figures 1 and 2, only three such leaf springs 8 are required to bias all the semiconductors 3 towards the base plate 4.

[0032] As shown in FIG. 6, the leaf spring 8 has two fixing openings 12 in a central fixing part 10 for positioning the leaf spring 8 with respect to the retaining bracket 6. The retaining bracket 6 has a retaining pin 9 which projects from the retaining bracket 6 in a direction towards the base plate 4. The retaining bracket 6 and the retaining pin 9 are integrally molded from aluminum, for example by die casting. Thus, in order to reduce assembly time, the retaining pin 9 and the retaining bracket 6 can be manufactured in one molding step. Alternatively, the retaining bracket 6 and the retaining pin 9 can be integrally molded from a plastic material, for example by injection molding, in order to reduce weight.

[0033] The retaining pin 9 extends through a corresponding fastening opening 12 in the leaf spring 8, which is attached to the retaining bracket 6 by deformation of the retaining pin 9. The end of the retaining pin 9 is preferably deformed so that the leaf spring 8 is not rigidly fixed to the retaining bracket 6, but rather is fixed in a floating manner. This has the advantage that the pin is not overstrained when applying a biasing force to the semiconductor and the spring can position itself accurately in the retaining bracket. To facilitate deformation of the retaining pin 9, the retaining pin 9 is provided with a conical recess 13 at its free end, as shown in FIG. 7.

[0034] As mentioned above, the retaining bracket 6 is attached to the base plate 4 by means of a number of screws 7. For this purpose, the retaining bracket 6 has a number of through holes 14, through which the screws 7 extend. The screws 7 can be located at an edge or corner of the bracket 6, away from the power semiconductors 3. The fixing screws 7 of the retaining bracket are thus not located between the power semiconductors 3. In this way, the electronic control unit can be made more compact.

[0035] The holding bracket 6 is further provided with at least two locating holes 15 for respectively receiving a plurality of first locating pins 16 which are fixed or received in holes in the base plate 4. The first locating pins 16 may also extend through locating holes 17 in the semiconductor board 2. Thus, the holding bracket 6 can be accurately positioned with respect to the base plate 4 and / or the at least one semiconductor board 2.

[0036] The retainer bracket 6 also has a plurality of second locating pins 18 for locating a logic control board (not shown) relative to the retainer bracket 6. The second locating pins 18 extend from the retainer bracket 6 in a direction away from the base plate 4. The logic control board is also disposed on the face of the retainer bracket 6 facing away from the base plate 4 and has corresponding locating holes or openings that receive the pins 18. The pins 18 can be formed from a metal, preferably steel. [Explanation of symbols]

[0037] 1 Electronic Control Unit 2 Semiconductor Board 3. Power Semiconductors 4 Base plate 5 Cooling fins 6 Retaining bracket 7 Screws 8. Leaf Spring 9 Retaining pin 10. Central fixing part of leaf spring 11 Forced arm 12 Fixed opening in leaf spring 13 Cone-shaped recess 14 Through hole 15 Positioning hole 16 First positioning pin 17 Positioning holes in semiconductor boards 18 Second positioning pin

Claims

1. An electronic control unit (1) for an electric drive system of an electric machine, the electronic control unit (1) comprises at least one semiconductor board (2) having a plurality of power semiconductors (3), a base plate (4) for dissipating heat generated in the electronic control unit (1), a retaining bracket (6) attached to the base plate (4), and an elastic biasing means (8) disposed between the retaining bracket (6) and the plurality of power semiconductors (3) to bias the power semiconductors (3) toward the base plate (4), - The retaining bracket (6) is an electronic control unit (1) having means for attaching the elastic biasing means (8) to the retaining bracket.

2. The electronic control unit (1) according to claim 1, wherein the elastic biasing means (8) is composed of a plurality of leaf springs (8).

3. The electronic control unit (1) according to claim 2, wherein each leaf spring (8) has a central fixing portion (10) and a plurality of biasing arms (11), the biasing arms (11) extend integrally from the central fixing portion (10) and are in contact with one of the power semiconductors (3) or the semiconductor board (2) in order to bias the power semiconductor (3) toward the base plate (4).

4. The electronic control unit (1) according to claim 3, wherein at least one of the leaf springs (8) has at least four biasing arms (11), the biasing arms (11) extending integrally from the central fixing portion (10) and each in contact with one of the power semiconductors (3) or the semiconductor board (2) to bias the power semiconductor (3) toward the base plate (4).

5. The electronic control unit (1) according to claim 2 or 3, wherein the leaf spring (8) has at least one fixing opening (12) in the central fixing portion (10).

6. The means for attaching the elastic biasing means (8) to the retaining bracket (6) includes a retaining pin (9) protruding from the retaining bracket (6), and the retaining bracket (6) and the retaining pin (9) are integrally molded, according to claim 1 or 2, the electronic control unit (1).

7. The electronic control unit (1) according to claim 6, wherein the retaining pin (9) extends through the corresponding fixed opening (12) in the leaf spring, and the leaf spring (8) is floatingly attached to the retaining bracket (6) by deformation of the retaining pin (9).

8. The electronic control unit (1) according to claim 7, wherein at least one of the leaf springs (8) has two fixed openings (12) for positioning the leaf spring (8) relative to the retaining bracket (6).

9. The retaining bracket (6) is attached to the base plate (4) by a plurality of screws (7), the electronic control unit (1) according to claim 1 or 2.

10. The electronic control unit (1) according to claim 9, wherein the screw (7) is located at the edge or corner of the bracket (6) and is spaced apart from the power semiconductor (3).

11. The electronic control unit (1) according to claim 1 or 2, wherein the retaining bracket (6) is provided with at least two positioning holes (15) for accommodating a plurality of first positioning pins (16) that are fixed to or housed in the base plate (4).

12. The electronic control unit (1) according to claim 1 or 2, wherein the retaining bracket (6) has a plurality of second positioning pins (18) extending away from the base plate for positioning the control board relative to the retaining bracket (6).

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