Control unit with integrally cast circuit board; system consisting of pump and control unit and manufacturing method for a control unit

Abstract

The present invention relates to a control unit (1), in particular for an electric pump (2), having a housing (3) which has at least a base portion (4) and side walls (5) projecting therefrom, wherein a circuit board (6) of the control unit (1) is arranged on the base portion (4) and the circuit board (6) is surrounded by the side walls. The side walls (5) project beyond the circuit board (6) and determine a protrusion volume (7) which is filled with an electrically insulating and thermally conductive potting compound (8).

Description

[0001] Control unit with molded circuit board; system comprising a pump and control unit and manufacturing method for a control unit

[0002] Description

[0003] The present invention relates to a control unit for an electric pump. The present invention further relates to a system comprising an (oil) pump and a control unit, and to a manufacturing method for a control unit.

[0004] Control units for electric oil pumps are well known. These pumps are used, for example, in (manual) transmissions for vehicles to build up fluid pressure in the transmission and to move components within the transmission through the application of pressure. Conventional control units are mounted on the outside of a transmission housing. A circuit board of the control unit is screwed directly onto the transmission housing. The circuit board is electrically connected to the pump, which is also attached to the transmission housing. Since the circuit board of the control unit is exposed on the transmission housing, it must be mounted on the transmission housing in a clean room. Otherwise, dirt, dust, or other environmental influences could lead to errors or short circuits on the circuit board and thus impair the functionality of the control unit.

[0005] US 2016 / 0 251 719 A1 discloses a system comprising an electric motor, a motor housing, and an electronics unit. A first housing shell is designed as a motor mount, and the motor housing is attached thereto. A second housing shell is designed as a cooling element. An electronics mount is arranged between the motor mount and the cooling element, with the cooling element and the motor mount having a higher thermal conductivity than the electronics mount.

[0006] DE 10 2020 104 241 A1 discloses an electric oil pump comprising a motor, a pump body, and a control unit mounted on the motor and configured to control the operation of the motor. A gear is arranged between the motor and the oil pump, reducing the rotational speed delivered by the motor to the oil pump.

[0007] However, there is no known solution from the state of the art that shields a control unit from environmental influences.

[0008] Brief description of the invention

[0009] The object of the present invention is therefore to overcome or at least mitigate the disadvantages of the prior art and, in particular, to provide a control unit that can be installed outside of a clean room. Furthermore, only a minimal amount of installation space should be required for the control unit.

[0010] This object is achieved according to the invention by a control unit according to the features of claim 1. Furthermore, the object of the present invention is achieved by a system according to the features of claim 9 and a manufacturing method according to the features of claim 10.

[0011] The present invention relates to a control unit or a control unit or a control device for an electric pump, in particular a hydraulic oil pump. The control unit has a housing that has at least one (plate-shaped) base section and side walls projecting therefrom (preferably transversely or substantially perpendicularly). A circuit board / circuit board / PCB of the control unit is arranged on the base section and is surrounded by the side walls. The side walls protrude beyond the circuit board and thereby define a projection volume that is (at least partially or partially / predominantly / completely) filled by an electrically insulating and thermally conductive potting compound.

[0012] In other words, the circuit board is surrounded by side walls. The side walls are designed to be so high that they protrude beyond the circuit board. This protruding section of the respective side walls forms a lateral boundary of the protrusion volume. The protrusion volume is filled with the potting compound in such a way that the circuit board is surrounded / enclosed by the potting compound. This means that the potting compound can act as a component of the control unit's housing. In particular, the potting compound can function as a cover for the housing.

[0013] The overhang volume can be a volume that is delimited by the side walls, a first plane that lies in the upper side of the circuit board oriented in the direction of the free ends of the side walls, and a second plane through the free ends of the side walls.

[0014] The core idea of ​​the present invention is that the circuit board of the control unit is cast into the potting compound or is completely surrounded by the potting compound.

[0015] The control unit according to the invention has the following advantages. By completely encapsulating the circuit board, dirt or other foreign bodies can be prevented from coming into contact with the circuit board and thus contaminating it. By preventing contamination of the circuit board, the risk of short circuits and / or other failures of the circuit board and thus of the entire control unit can be reduced. This eliminates the need to assemble an entire system to which the control unit is attached in a clean room. In particular, the entire system can be a gearbox with a housing to which the control unit and the pump are attached. With the encapsulated / encapsulated circuit board, the gearbox can be mounted outside the clean room without risking contamination of the circuit board. This can reduce manufacturing and assembly costs.Furthermore, the control unit according to the invention has a space-optimized housing. Furthermore, the contact between the circuit board and the potting compound creates a thermally conductive bridge that can dissipate excess thermal energy from the circuit board. Thus, the potting compound can act as a heat sink for the circuit board. Furthermore, by eliminating the cover, installation space can be saved. The electrically insulating properties of the potting compound also allow air and creepage distances to be reduced. In particular, the insulating potting compound can reduce air and creepage distances between the circuit board and conductive parts outside the housing.

[0016] Furthermore, the object of the present invention is achieved by a system comprising a pump and the control unit according to one of the aforementioned aspects. The pump and the control unit can both be arranged on a transmission housing of a (manual) transmission.

[0017] The object of the present invention is further achieved by a manufacturing method for the control unit. The manufacturing method has the following steps. The circuit board is placed on the bottom section of the housing such that the side walls of the housing protrude beyond the circuit board and determine the protrusion volume. A connector is inserted into the housing. The connector is connected to the circuit board. In particular, the connector is connected to the circuit board by a press fit. In particular, protruding pins on the connector can be inserted through corresponding holes / recesses in the circuit board. The combination of the pins and the holes can form the press fit. Subsequently, placeholders are placed on the connections of the connector. The placeholders can in particular be plastic caps that have the shape of the counterparts of the connections.This allows the placeholders to form a negative in the potting compound that takes the shape of the counterparts. In a final step, the connector and the circuit board are potted with a potting compound in such a way that the excess volume is filled and the connections are left untouched.

[0018] Advantageous further developments of the present invention are the subject of the appended subclaims.

[0019] Preferably, the protrusion volume can be delimited from a plane that runs through a side wall end of the side walls by an upper side of the circuit board opposite the base section and the inner sides of the side walls. The potting compound in the protrusion volume can thus fill the side walls that protrude beyond the circuit board. The potting compound in the protrusion volume can thus serve as a cover for the housing of the control unit. According to a further advantageous aspect of the present invention, the side walls can form a polygon (preferably a rectangle) in the interior of which the circuit board is accommodated. Due to the rectangular shape, the essentially rectangular circuit board can fit well into the side walls.

[0020] Preferably, a gap can be provided between the circuit board and the side walls. This means that the side walls and the circuit board can be spaced apart from each other. The distance between the side walls and the circuit board can represent the air and / or creepage distance between the (electrically conductive) circuit board and other electrical components located outside the side walls.

[0021] According to a further advantageous aspect of the present invention, the gap can be filled with potting compound. This allows the entire interior of the housing not used by the circuit board to be filled with potting compound. The electrically insulating material of the potting compound can prevent arcing.

[0022] According to an advantageous aspect of the present invention, the control unit can have the connector or a circuit board that is surrounded by the side walls and is (electrically) connected to the circuit board. The connector can, in particular, be an electrical plug. The connector can, in particular, be used for an electrical connection from the control unit to the pump. The connector can, in particular, be a circuit board-side connector that can be connected to a corresponding pump-side connector to form a connector system. While the circuit board-side connector can be surrounded by the side walls, the pump-side connector can be arranged on the gear housing. The electrical connection to the pump can originate from the pump-side connector.

[0023] Preferably, the connector can be surrounded at least in sections by the potting compound, wherein the potting compound can form an insulating connector housing for the connector. This means that the potting compound can represent an insulating material for the connector. The connector housing can be made of an insulating material, such as plastic, and can have (metallic / electrically conductive) connections that are recessed from the connector housing or protrude from the connector housing. The (insulating) connector housing can thus be replaced by the (likewise electrically insulating) potting compound. This can save material and manufacturing costs.

[0024] It can therefore be advantageous for the connections or (connector) pins of the connector to be left free from the potting compound. The connections allow the connector to be (electrically) connected to the corresponding pump-side connector. The protruding connections can accommodate corresponding male connections of the pump-side connector. Furthermore, the connections can also be designed (male or protruding from the connector housing) in such a way that they engage with corresponding female connections of the pump-side connector. This means that the electrically conductive elements can be left free from the potting compound. In particular, placeholders or push-on caps can be used for this purpose, which can ensure that the connections remain free when the potting compound is poured in.

[0025] Advantageously, the circuit board and the connector can be connected by a press fit. For this purpose, the circuit board can have holes into which the protruding (connection) pins of the connector engage. The diameter of the pins can be designed such that a press fit exists between the pins and the holes.

[0026] Advantageously, the side walls of the housing can be continuous or continuous. This prevents the potting compound from leaking out during pouring. The continuous side walls can therefore serve as formwork for the casting.

[0027] The potting compound can be made of a synthetic resin or a thermosetting plastic. Epoxy resins or polyurethane are particularly suitable. Furthermore, the potting compound can be made of silicone rubber (synthetic polysiloxane polymer with an additive platinum catalyst), polyacrylate, or a gel potting compound.

[0028] The casting compound can, for example, be between approx. 1 mm and approx. 5 mm thick and cover an area of ​​20,000 mm 2 up to 30,000 mm 2 A thickness to volume ratio of the casting compound can be between approximately 5 mm / 20,000 mm 3 up to approx. 1 mm / 150,000 mm 3 lay.

[0029] The control unit or the circuit board can in particular be operated with a nominal voltage of 12 V.

[0030] In particular, a material that has a thermal conductivity greater than approximately 1 W / mK can be understood as thermally conductive.

[0031] The thermal conductivity of the potting compound can be adjusted, for example, by additives in the potting compound.

[0032] The casting compound preferably has the highest possible specific heat capacity. A high specific heat capacity can, for example, be higher than that of air, i.e., higher than 1 kJ / kgK.

[0033] Preferably, the housing of the control unit can be cast. The housing can be made of the same material as the gearbox housing.

[0034] The invention is explained in more detail below with reference to the figures:

[0035] Fig.1 shows a perspective view of a control unit according to the present invention;

[0036] Fig. 2 shows a perspective view of the control unit according to the present invention without potting compound;

[0037] Fig. 3 shows a longitudinal sectional view through the control unit according to the present invention; Fig. 4 shows a detailed view of a connector of the control unit according to the present invention;

[0038] Fig. 5 shows a plan view of the control unit according to the present invention;

[0039] Fig. 6 shows a perspective view of a system according to the present invention;

[0040] Fig. 7 shows a perspective view of the system according to the present invention without a housing;

[0041] Fig. 8 shows a detailed view of a connector portion of the control unit according to the present invention; and

[0042] Fig. 9 shows a flowchart of a manufacturing method according to the present invention.

[0043] The figures are merely schematic and serve solely to clarify the invention. The same elements are designated by the same reference numerals.

[0044] Figures 1 and 2 show a control unit 1 and a control device for an electric pump 2, respectively. The control unit 1 has a housing 3 which has at least a base section 4 and side walls 5 protruding therefrom. The side walls 5 protrude essentially perpendicularly from the base section 4. A circuit board 6 of the control unit 1 is arranged on the base section 4 and is surrounded by the side walls 5. The side walls 5 protrude beyond the circuit board 6 and thereby define a projection volume 7 which is filled with an electrically insulating and thermally conductive potting compound 8. The projection volume 7 is defined by a plane through side wall terminations 9 of the side walls 5, a top side 10 of the circuit board 6 and inner sides of the side walls 5. A gap 11 is formed between the circuit board 6 and the inner sides of the side walls 5.The gap 11 is also filled with the potting compound 8 in order to completely surround the circuit board 6 with the potting compound 8. The control unit 1 further comprises an (electrical) connector 12. The connector 12 is also arranged within the side walls 5 and is connected to the circuit board 6. The circuit board 6 and the connector 12 are connected, for example, by a press fit. Furthermore, the control unit 1 comprises another electrical connector 15, which serves, for example, for the power supply.

[0045] Fig. 3 shows a longitudinal section through the control unit 1. The sectional view shows the gap 11, which is filled by the potting compound 8. As a result, the circuit board 6 is (almost) completely surrounded by the potting compound 8 and thus shielded from environmental influences and / or contamination.

[0046] Fig. 4 shows the connector 12 with an (insulating) connector housing or insulation section 13 and terminals 14. The insulation section 13 is designed such that it leaves the terminals 14 free. This means that the metal contact points of the terminals 14 are freely accessible and can be connected to a corresponding (contact) counterpart. Fig. 5 shows the arrangement of the terminals 14. The terminals are arranged in a row next to one another and run parallel to the side wall 5, which faces the connector 12.

[0047] Fig. 6 shows a gear housing 16. The pump 2 and the control unit 1 are attached to the gear housing 16. The control unit 1 is electrically connected to the pump 2. Cables that connect the control unit 1 to the pump 2 are routed on an outer side of the gear housing 16. The control unit 1 is attached to the gear housing 16 in an upside-down or reversed manner. The side wall terminations 9 thus rest against the gear housing 16 and the base cut 4 points outwards from the outer side of the gear housing 16. This means that the potting compound 8 is arranged between the gear housing 16 and the printed circuit board 6. The plug 15 protrudes outwards from the housing 3. The printed circuit board 6, which is surrounded by the potting compound 8, allows the control unit 1 to be mounted on the gear housing without the assembly having to take place in a clean room.

[0048] Fig. 7 shows the gear housing 16 without the housing 3 of the control unit 1. The circuit board 6 is connected to the connector 12. The connector 12 is connected to another pump-side connector section 17. In particular, the connections 14 point in the direction of the gear housing 16 and the pump-side connector section 17. Fig. 8 shows a detailed view of the pump-side connector section 17. The pump-side connector section 17 has an insulating housing 18 and (electrically conductive) pins 19 that protrude from the housing 18. The pins 19 are prepared and designed to engage in the connections 14 of the connector 12 to establish an electrical connection. The pump-side connector section 17 is electrically connected to the pump 2 by cables 20. The circuit board 6 is electrically connected to the pump 2 via the pump-side connector section 17. Thus, the control unit 1 can send electrical (control) signals to the pump 2.

[0049] Fig. 9 shows a flowchart of a manufacturing method for the control unit 1. The manufacturing method has the following steps. In the first step S1, the printed circuit board 6 is placed on the base section 4 such that the side walls 5 protrude beyond the printed circuit board 6 and determine the protrusion volume 7. In the second step S2, the connector 12 is inserted into the housing. The connector 12 is connected to the printed circuit board 6 in the third step S3. In the fourth step S4, placeholders are placed on the connections 14 of the connector 12. In the fifth step S5, the connector 12 and the printed circuit board 6 are cast together with the casting compound 8 so that the protrusion volume 7 is filled and the connections 14 are left unfilled by the casting compound 8.

[0050] List of reference symbols

[0051] 1 control unit

[0052] 2 pumps

[0053] 3 housings

[0054] 4 floor section

[0055] 5 side walls

[0056] 6 circuit board

[0057] 7 Supernatant volume

[0058] 8 Potting compound

[0059] 9 Side wall finish

[0060] 10 Top

[0061] 11 gap

[0062] 12 connector

[0063] 13 Insulation section / connector housing

[0064] 14 connections

[0065] 15 plugs

[0066] 16 Gearbox housing

[0067] 17 pump-side connector section

[0068] 18 housings

[0069] 19 pins

[0070] 20 cables

[0071] S1 first step

[0072] S2 second step

[0073] S3 third step

[0074] S4 fourth step

[0075] S5 fifth step

Claims

Claims 1 . Control unit (1 ), in particular for an electric pump (2), with a housing (3) which has at least one base section (4) and side walls (5) projecting therefrom, wherein a printed circuit board (6) of the control unit (1 ) is arranged on the base section (4) and the printed circuit board (6) is surrounded by the side walls, characterized in that the side walls (5) protrude beyond the printed circuit board (6) and in this way determine a protrusion volume (7) and the protrusion volume (7) is filled with an electrically insulating and thermally conductive potting compound (8).

2. Control unit (1) according to claim 1, characterized in that the overhang volume (7) is delimited by a plane which runs through a side wall end (9) of the side walls (5), by an upper side (10) of the printed circuit board (6) opposite the base section (4) and by inner sides of the side walls (5).

3. Control unit (1) according to claim 1 or 2, characterized in that the side walls (5) form a polygon, in the interior of which the printed circuit board (6) is accommodated.

4. Control unit (1) according to one of the preceding claims, characterized in that a gap (11) is present between the circuit board (6) and the side walls (5).

5. Control unit (1) according to claim 4, characterized in that the gap (11) is filled with casting compound (8).

6. Control unit (1) according to one of the preceding claims, characterized by a connector (12) which is surrounded by the side walls (5) and is connected to the printed circuit board (6).

7. Control unit (1) according to claim 6, characterized in that the connector (12) is at least partially surrounded by the potting compound (8), wherein the potting compound (8) forms an insulating connector housing (13) of the connector (11).

8. Control unit (1) according to claim 6 or 7, characterized in that terminals (14) of the connector (11) are recessed from the casting compound (8).

9. System comprising a pump (2) and a control unit (1) according to one of the preceding claims, wherein the pump (2) is electrically connected to the control unit (1), and the connector (12) of the control unit (1) is electrically connected by the terminals (14) to a corresponding pump-side connector section (17).

10. Manufacturing method of a control unit (1) comprising the following steps: - placing a printed circuit board (6) on a base section (4) of a housing (3) of the control unit (1) in such a way that side walls (5) of the housing (3) protrude beyond the printed circuit board (6) and determine a protrusion volume (7); - inserting a connector (12) into the housing (3); - connecting the connector (12) and the circuit board (6), in particular by a press fit; - Placing placeholders on the terminals (14) of the connector (12); - Potting the connector (12) and the printed circuit board (6) with a potting compound (8) such that the overhang volume (7) is filled and the connections (14) are left free from the potting compound (8).

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