Electrical appliance

Abstract

The invention relates to an electrical appliance comprising: - a printed circuit board which is populated with a heat-generating component, - a heat sink having at least one cooling fin, and - a housing part, wherein a bushing is inserted into a recess in the cooling fin, wherein a screw, the screw head of which presses the printed circuit board, together with the component, towards the heat sink, is screwed into an internal thread of the bushing, and wherein the bushing has a polyhedral region which is pressed into the housing part.

Description

[0001] electrical appliance

[0002] Description:

[0003] The invention relates to an electrical device.

[0004] It is generally known that an electrical device has a heat-generating component, such as a power semiconductor, which is connected to a heat sink for heat dissipation.

[0005] The invention is therefore based on the object of developing an electrical device in which efficient heat dissipation can be achieved.

[0006] According to the invention, the object is achieved in the electrical device according to the features specified in claim 1.

[0007] Important features of the invention in the electrical device are that the electrical device has a printed circuit board which is equipped with a heat-generating component, in particular a power semiconductor, a heat sink with at least one cooling fin and a housing part, wherein a socket, in particular a press-in socket, is inserted into a recess in the cooling fin, wherein a screw, the screw head of which presses the printed circuit board with the component towards the heat sink, is screwed into an internal thread of the socket, wherein the socket has a polygonal area which is pressed into the housing part, in particular wherein the screw axis of the screw and / or the thread axis of the internal thread is aligned perpendicular to the direction of extension of the cooling fin, in particular wherein the socket is made of steel, the housing part is made of aluminum or steel and the cooling fin is made of aluminum.

[0008] In particular, the bushing forms a press fit with the cooling fin and the bushing also forms a press fit with the housing part.

[0009] The advantage here is that, on the one hand, the socket is firmly connected to the housing part, and, on the other hand, the screw, when screwed into the socket, positions and / or presses the socket against a step of the heat sink. This presses the circuit board with the component against the heat sink, improving and ensuring heat transfer. At the same time, the screw and press-in nut serve as an electrical ground connection for the housing part, connecting it to a conductor track on the circuit board.

[0010] To increase the safety of the electrical earth connection, the connection can optionally be made double and thus more secure.

[0011] In an advantageous embodiment, the socket has a toothing cut into the material of the cooling fin, in particular, the recess being a blind hole and the toothing cut into the material of the cooling fin at the bottom of the blind hole. Thus, the heat sink is also electrically securely connected and grounded to the socket and thus also to the screw and the housing part. A PE connection can also be implemented instead of the ground connection.

[0012] In an advantageous embodiment, the toothing is an external toothing. The advantage here is that the toothing cuts into the recess of the heat sink.

[0013] In an advantageous embodiment, the screw extends through the heat sink, in particular through the cooling fin. This advantageously provides an electrical connection between the circuit board and the housing part.

[0014] In an advantageous embodiment, the housing part is arranged on the side of the heat sink facing away from the circuit board, and / or the circuit board is arranged on the side of the heat sink facing away from the housing part. Advantageously, the housing part can be electrically connected by means of the screw to a conductor track of the circuit board, which can be arranged on the other side of the heat sink in a mechanically protected manner.

[0015] In an advantageous embodiment, the housing part is manufactured as a stamped and bent part from sheet metal. This is advantageous because it allows for simple manufacturing.

[0016] In an advantageous embodiment, the polygonal region is arranged flush with the housing part on at least one side of the housing part, in particular on the side of the housing part facing away from the heat sink.

[0017] In an advantageous design, the polygonal area on the bushing protrudes radially. This has the advantage of achieving a high degree of rotational stability.

[0018] In an advantageous embodiment, the polygonal area is spaced apart from the toothing. It is advantageous that the housing part is spaced apart from a step in the receiving area of ​​the circuit board against which the socket is positioned.

[0019] In an advantageous embodiment, the recess is an interruption in the cooling fin. It is advantageous that the cooling fin has a thickened area in which a hole is provided as a recess.

[0020] In an advantageous embodiment, the bushing is made of steel. This allows for simple and cost-effective production.

[0021] In a preferred embodiment, the heat sink is made of aluminum. This allows the bushing to easily cut into the heat sink material.

[0022] In an advantageous embodiment, the cooling fin has a thickened portion that is interrupted by the recess, in particular, the bushing is inserted into the recess and thus accommodated in the thickened portion. This is advantageous because the bushing can be accommodated easily and securely.In an advantageous embodiment, a further socket, in particular a further press-in socket, is inserted into a further recess of a further cooling fin of the heat sink, wherein a further screw, the screw head of which presses the circuit board with a further component towards the heat sink, is screwed into an internal thread of the further socket, wherein the further socket has a further polygonal area which is also pressed into the housing part, wherein the further socket has a further toothing which is cut into the material of the further cooling fin, wherein the further toothing is also an external toothing, wherein the further screw projects through the heat sink, in particular through the further cooling fin. The advantage here is that a sufficiently secure earth connection can be established. This is because the two screws function as an independently functioning electrical earth wire or PE wire.If one of the screws fails, the other one ensures the function.

[0023] In an advantageous embodiment, the bushings, particularly by means of their cylindrical outer circumference, align the housing part relative to the heat sink in a form-fitting manner. This is advantageous because the housing part is aligned with the connecting line between the two bushings, and the cylindrical outer shape of the bushings ensures highly precise centering of the housing part relative to the bushings.

[0024] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art. The invention will now be explained in more detail with reference to schematic illustrations:

[0025] Figure 1 shows a cross section through a region of an electrical device according to the invention, wherein a socket 1 is used.

[0026] Figure 2 shows an oblique view of a cut-away area of ​​the electrical device.

[0027] Figure 3 shows an oblique view of the socket 1.

[0028] Figure 4 shows the connection of the sockets 1 with a housing part 5 of the electrical device.

[0029] As shown in the figures, the electrical device has a circuit board 3 which is pressed towards a heat sink 2 by the screw head of a screw 4.

[0030] Thus, a heat-generating component, in particular a power semiconductor, mounted on the circuit board 3 is pressed against the heat sink 2, in particular to improve the thermal coupling of the component to the heat sink 2.

[0031] The bushing 1 is preferably designed as a press-in bushing.

[0032] The bushing 1 is inserted into a recess, in particular an interruption, of a cooling fin 20 of the heat sink 2 and has an internal thread into which a threaded portion of the screw 4 is screwed, wherein the bushing 1 is supported in the cooling fin 20 at a step of the cooling fin 20.

[0033] The bushing 1 has a polygonal portion 31, in particular a hexagonal portion, which protrudes from the cooling fin 20 and is pressed into a housing part 5 made of sheet metal. Thus, the bushing 1 is non-rotatably embedded in the housing part 5 and non-rotatably connected to the housing part 5.

[0034] At the end of the bushing 1 facing away from the polygonal area 31, the bushing 1 has a toothing 30, with which the bushing 1 is inserted into the cooling fin 20 such that the toothing 30 is cut into the material of the cooling fin 20. The heat sink 2 including the cooling fin 20 is preferably made of aluminum; the bushing 1 is preferably made of steel.

[0035] The sheet metal of the housing part 5 is preferably made of sheet steel. In particular, the housing part 5 is designed as a stamped and bent part.

[0036] The toothing 30 is designed as an external toothing.

[0037] The housing part 5 is preferably arranged on the side of the heat sink 2 facing away from the circuit board 3.

[0038] The housing part 5 is detachably connected to the heat sink.

[0039] A pressure plate 7 is arranged between the screw head and the circuit board 3, so that the force flow introduced by the screw 4 is spread out and thus the circuit board 3 is protected from excessive pressure. The pressure plate 7 is preferably made of metal, so that the housing part 5 is electrically connected to a conductor track of the circuit board 3 via the metal socket 1 and the metal screw 4, as well as the metal pressure plate 7. In this way, an earth connection and / or PE connection can be provided for the housing part 5.

[0040] The screw axis of the screw 4 is aligned perpendicular to the direction of extension of the cooling fin 20.

[0041] Preferably, the electrical device is a converter that supplies power to an electric motor and thus controls or regulates its speed or torque. The circuit board accommodates not only the signal electronics, which generates control signals for the component, in particular the power semiconductor, but also the converter's power electronics, which encompasses the component, in particular the power semiconductor.

[0042] In further embodiments according to the invention, the component is a power module comprising several power semiconductors.

[0043] 1 socket, especially press-in socket 2 heat sink

[0044] 3 circuit board

[0045] 4 screw

[0046] 5 Housing part

[0047] 6 Heat-generating component 7 Pressure plate

[0048] 20 cooling fins

[0049] 30 Gearing

[0050] 31 Polygonal area, especially hexagonal area

Claims

Patent claims:

1. An electrical device, in particular an inverter feeding an electric motor, comprising a printed circuit board which is equipped with a heat-generating component, in particular a power semiconductor, a heat sink with at least one cooling fin, and a housing part, characterized in that a socket, in particular a press-in socket, is inserted into a recess of the cooling fin, wherein a screw, the screw head of which presses the printed circuit board with the component towards the heat sink, is screwed into an internal thread of the socket, wherein the socket has a polygonal area which is pressed into the housing part, in particular wherein the socket forms a press connection with the cooling fin and the socket also forms a press connection with the housing part, in particular wherein the recess is arranged in a thickening of the cooling fin,in particular wherein the screw axis of the screw and / or the thread axis of the internal thread is or are aligned perpendicular to the direction of extension of the cooling fin, in particular wherein the bushing is made of steel, the housing part is made of aluminum or steel and the cooling fin is made of aluminum.

2. Electrical device according to claim 1, characterized in that the socket has a toothing which is cut into the material of the cooling fin, in particular wherein the recess is a blind hole and the toothing is cut into the material of the cooling fin at the bottom of the blind hole.

3. Electrical device according to one of the preceding claims, characterized in that the toothing is an external toothing.

4. Electrical device according to one of the preceding claims, characterized in that the screw protrudes through the heat sink, in particular through the cooling fin.

5. Electrical device according to one of the preceding claims, characterized in that the housing part is arranged on the side of the heat sink facing away from the printed circuit board, and / or that the printed circuit board is arranged on the side of the heat sink facing away from the housing part.

6. Electrical device according to one of the preceding claims, characterized in that the housing part is made as a stamped and bent part from a sheet metal.

7. Electrical device according to one of the preceding claims, characterized in that on at least one side of the housing part, in particular on the side of the housing part facing away from the heat sink, the polygonal area is arranged flush with the housing part.

8. Electrical device according to one of the preceding claims, characterized in that the polygonal area on the socket protrudes radially.

9. Electrical device according to one of the preceding claims, characterized in that the polygonal region is spaced from the toothing.

10. Electrical device according to one of the preceding claims, characterized in that the recess is an interruption of the cooling fin.

11. Electrical device according to one of the preceding claims, characterized in that the socket is made of steel.

12. Electrical device according to one of the preceding claims, characterized in that the heat sink is made of aluminum.

13. Electrical device according to one of the preceding claims, characterized in that the cooling fin has a thickening which is interrupted by the recess, in particular wherein the socket is inserted into the recess and is thus received in the thickening.

14. Electrical device according to one of the preceding claims, characterized in that a further socket, in particular a further press-in socket, is inserted into a further recess of a further cooling fin of the heat sink, wherein a further screw, the screw head of which presses the circuit board with a further component towards the heat sink, is screwed into an internal thread of the further socket, wherein the further socket has a further polygonal area which is also pressed into the housing part, wherein the further socket has a further toothing which is cut into the material of the further cooling fin, wherein the further toothing is also an external toothing, wherein the further screw projects through the heat sink, in particular through the further cooling fin.

15. Electrical device according to one of the preceding claims, characterized in that the sockets, in particular by means of their cylindrical outer circumference, align the housing part in a form-fitting manner relative to the heat sink.

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