EP1685596A2

EP1685596A2 - Electric motor and method for producing said motor

Info

Publication number: EP1685596A2
Application number: EP04791344A
Authority: EP
Inventors: Peter Urbach; Wolfgang Feiler; Thomas Raica; Stefan Hornung
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2003-11-08
Filing date: 2004-10-29
Publication date: 2006-08-02
Also published as: US7687947B2; DE10352079A1; CN100449756C; CN1879217A; WO2005046020A2; WO2005046020A3; US20070133183A1; JP2007509594A; JP4217742B2

Abstract

The invention relates to an electric motor (10), in particular for displacing moving parts in a motor vehicle. Said motor comprises an electronic unit (70) with a sandwich construction, which contains a first electrically conductive substrate (71) and a second electrically conductive substrate (72). Power components are located between said substrates and are electrically connected to both substrates (71, 72). The side (84) of the second substrate (72) facing away from the first substrate (71) is equipped with additional electronic components (56). The first substrate (71) is configured as a conductive punched grid (44), which together with the second substrate (72) is surrounded by a plastic body (95) in an insert moulding process, in such a way that extensions (97) of the punched grid (44) protrude from the plastic body (95), forming an electrical and/or mechanical interface (98) for connecting additional motor components (99, 38, 40, 104, 102, 80).

Description

Electric motor, and method for producing such

State of the art

The invention relates to an electric motor, in particular for moving movable

Parts in the motor vehicle, and a method for producing such an electric motor according to the type of the independent claims.

A power semiconductor module has become known from DE 34 06 528 A1, at least one semiconductor component being arranged between two parallel substrates and being contacted with a metallization on the substrates. Ceramic plates are used as substrates, on which all line connections are applied in the form of metallic conductor tracks. The power semiconductor module can be inserted into a housing that is at least partially filled with a sealing compound.

If such a semiconductor module is to be used to control an electric motor, it forms a separate electronics unit due to the use of the two metallized ceramic substrates, which cannot be integrated directly into the installation space of the motor housing, since they are only contacted electrically with the electric motor via an electronic connector can.

Advantages of the invention

The electric motor according to the invention with the features of the independent claims has the advantage that by designing a substrate as a lead frame with projections that protrude from the molded plastic body, the electronic unit directly provides electrical and mechanical connections that are designed to be so stable that further components of the electric motor can be connected directly to the electronic unit. This has the advantage that the electronics module in the

Engine space can be integrated into the engine directly on the armature shaft, eliminating the need for additional electrical connections and mechanical brackets for certain engine components. The measures listed in the subclaims result in advantageous developments and improvements to the features mentioned in claim 1.

The method according to the invention for producing an electric motor with an electronic control unit according to the features of independent claim 21 has the advantage that, by connecting a mechanically stable lead frame with a ceramic substrate in a sandwich construction, very powerful and compact control electronics in a cost-effective and easily variable process can be manufactured. The direct connection of motor components to the control unit eliminates additional process steps, because together with the assembly of the electronics unit, further motor components such as brush holders, shielding surfaces, connector pins and connections to external electrical components are fully assembled.

In today's control devices, the logic and power sections are usually structurally separate from one another. The logic today is implemented either on printed circuit boards or ceramic substrates such as LTCC. For applications with low power consumption, components with housings such as TO220 PowerMOS transistors can be used on the circuit board for the power section, but require additional heat sinks. In high-current applications such as electric power steering, the

Power transistors soldered as bare dies on DBC substrates. State of the art is the contacting of the chip top using thick wire bonds. The high footprint of the bond feet and the limited current carrying capacity, together with reliability problems, limit this technology, especially for high-current applications. Further disadvantages of the bond technology are poor switching behavior

Stray inductances and missing test concepts for parallel bond loops. Power and logic substrates are wired in control units via additional lead frames and bonding technology. These concepts are very space-intensive. The assembly of the electronics, in particular the power section, on heat sinks, such as the housing of the control unit or the end shield of the motor, using thermal adhesive or film is not optimal for thermal management.

The demand for higher integration density and reliability as well as improved thermal management leads to a new concept in assembly and connection technology. The aim is on the one hand to combine logic and power components combine and at the same time optimize the systems with regard to reliability. Therefore, according to the invention, a suitable assembly and connection technology (AVT) is used which, for example, by soldering the power components on both sides between suitable wiring carriers and direct large-area contacting on heat sinks, improves both the electrical and the thermal and thermomechanical performance. This inventive technology of double-sided soldering of power components between two substrates to form a sandwich is used here to connect a plurality of power transistors, which have both a solderable chip rear side and a solderable chip front side, between two substrates (eg DBC), which have an application-specific wiring, to solder. The solderability of the front side of the chip is achieved by applying solder bumps.

Both substrates perform functions of mechanical stabilization, heat dissipation and electrical wiring as well as electrical insulation from cooling surfaces, the DBC substrates also preferably being suitable for high ones

Currents are suitable.

For applications with smaller currents, the technology according to the invention offers approaches to miniaturization or integration by combining power, logic and sensor technology in one module, which can result in potential for further reduction of costs, in particular system costs.

The object of the invention is to present window electronics with the aim of direct integration into the motor and reducing the costs, the installation space and the weight in comparison to electronics which correspond to the prior art. The core is a mechatronic module based on sandwich technology, which combines all electrical and mechanical functions, ie it contains power, logic, sensors and the substrates required for the sandwich as well as the housing. Thanks to the concept of sandwich technology and the multifunctional use of, for example, the lead frame (first substrate), additional elements for wiring, in particular bonds, can be dispensed with. This is achieved in that power components (for example power MOSFETs) are glued or soldered between a first substrate, preferably a lead frame (alternatively also DBC, Direct Bond Copper) and a second substrate, preferably a ceramic substrate, and the control logic on the top of the second substrate of the power section and the Sensors is equipped. The two substrates are contacted in parallel to the contacting of the power components between the first and the second substrate, as a result of which all electrical and mechanical connections are made within the module. The sandwich structure created in this way is used to protect against environmental influences and against mechanical damage

Provide a plastic injection molding process with a housing.

The advantages of the invention are as follows:

a) Miniaturization of the structure

An advantage for the direct integration of the electronics in the motor is the reduction in installation space and weight through the use of sandwich technology and the use of bare die components for the power and active logic components, i.e. Avoidance of space-intensive prepacked components. Furthermore, the sandwich structure and the use of bare die

Components make the dimensions of the substrates smaller compared to standard technologies, which results in cost advantages despite the use of a logic substrate which is more expensive than the printed circuit board.

b) Multifunctional leadframe as the first substrate

The first substrate, preferably a lead frame, combines a number of functions. It is primarily used for electrical contacting of the power components and together with the second substrate for their electrical connection, i.e. to represent the electr. Function of the power section. In addition, the lead frame cools the power components, so the geometry of the assembly area is the

Power components selected so that optimal heat dissipation can take place. For this reason, materials with good electrical and thermal properties are particularly advantageous, preferably Cu alloys or materials with similar properties. Since a soldering or gluing process is preferably used as the joining process between the power components and the lead frame, one is for the

To provide processes with a suitable surface, ie if Cu alloys are used, an appropriate surface, such as nickel, can be dispensed with if the appropriate measures are taken in the manufacture of the lead frame. In addition to the appropriate choice of materials, the choice of Material thickness, in turn, additional functions such as connector pins can be implemented, which are used for standardized connector systems.

Other elements that can be integrated into the lead frame are, for example, spring clips for mounting the carbon brushes, bores for receiving the module in the application and interfaces for connecting external components or

Contacting the motor. The interfaces for the external components, for example wired capacitors, inductors or strands of carbon brushes, can be designed in the construction of the lead frame so that the components can be contacted, for example insulation displacement technology, using inexpensive joining methods, i.e. it can be cost-intensive thermal processes such as

Avoid welding.

The contact between the leadframe and the logic substrate can be achieved without the need for additional components if the leadframe is shaped appropriately, if, for example, embossing and punching increases or increases in the manufacturing process by means of appropriate shape-related manufacturing processes

Depressions are generated. In principle, spring elements, which in turn are suitable for electrical contacting, can also be produced, for example, by embossing and thus reducing the material thickness with a suitable shape. Furthermore, the manufacturing processes are suitable for generating contours that mechanically stabilize the lead frame or for sealing the module in

Contribution to the housing. These contours are so-called U- or V-grooves and "anchor holes" as well as undercuts, which simultaneously serve to mechanically stabilize the module and thus ensure its reliability. Another functional element is the so-called dam bar, which covers the individual areas The DamBar has the advantage that, firstly, several individual parts can be connected to form an easily manageable part, which also significantly reduces the complexity of the workpiece carriers and joining aids Injection molding tool can also be made easier.

The functions described above can be implemented in parallel in the production of the lead frame, since shape-related processes such as stamping, embossing and bending are used for the production of the lead frame, the resulting costs are essentially caused by tools, which are usually high Output with the same quality. This means that in order to achieve the overall function of the lead frame, in comparison to the construction technologies corresponding to the state of the art, no further manufacturing steps are required which would cause additional costs.

c) logic substrate as second substrate

A logic substrate, which is a further development of a ceramic substrate, is preferably used as the second substrate. This substrate has several advantages that make this substrate technology particularly attractive for module technology. In contrast to ceramic substrates which correspond to the prior art, the substrate is suitable for high currents, i.e. This means that the technology can be scaled across various performance ranges and can also be manufactured more cost-effectively. The universal surface, which is both adhesive and solderable, is particularly advantageous on this logic substrate. This makes it possible to populate the logic components in the form of bare die and SMD in the state-of-the-art conductive adhesive technology on the front (logic side) in order to subsequently mechanically and electrically insert the pre-assembled module together with the power components and the first substrate a joining step preferably to connect soldering step. In principle, adhesive processes are also conceivable as a joining technique.

The use of standard technology for assembly on the logic side is particularly advantageous for cost reasons, since the assembly of the substrate as a large card is possible, which means that a number of production steps, such as printing the conductive adhesive, can be carried out in parallel at low cost. In principle, it is also conceivable that the substrate is not populated in the large card, but rather as a single substrate. This variant is necessary if the substrate is first to be connected to the power unit and the first substrate and then to be equipped with the logic components.

From a technical point of view, the use of a ceramic substrate is advantageous because the coefficient of expansion of the ceramic is significantly better than that of silicon and

Mold packaging is adapted as other substrates, for example printed circuit board (FR4). Since it is possible in this substrate material to implement so-called vias for representing electrical connections between the front and back of the substrate, additional elements and processes can result in additional costs cause and require installation space, are waived. Among other things, this enables a very compact design of the electronics.

d) Symmetrical structure The power components and the joints between the

Arrange power components or lead frames and logic substrates so that the structure is as symmetrical as possible. A symmetrical structure is particularly advantageous in the case of thermomechanical loads, since it can be assumed that the resulting forces are distributed evenly and thus improve reliability, i.e. the lifespan is increased. Furthermore, a symmetrical structure and short conductor lengths should also improve the EMC (electro-magnetic compatibility behavior). In particular, a symmetrical cable routing of the power outlets and the connection to the shielding plates is advantageous in order to ensure optimal functioning of interference suppression components that can be integrated in the module Technology according to the invention are shown.

e) Integration of the interference suppression component in the module

The integration of any necessary interference suppression components into the module is advantageous since components are available on the market, for example X2Y, which take over the interference suppression function and as SMD components in the

Standard assembly process of the logic substrate can be integrated. By dispensing with external interference suppression components (usually consisting of inductance and capacitance), which are usually wired, additional cost-intensive process steps, such as welding to contact the wired components, are not required outside the module. In addition, there are no external ones

Components that generally have significantly larger dimensions than SMD components, construction space advantages that are advantageous for the overall integration of the module into the application due to the reduction in installation space. The handling and assembly of the module is also simplified by the elimination of external components, since the potential risk of damaging these components is eliminated.

f) Use of bare die components

In order to achieve the objective in terms of miniaturization, it is advantageous to use bare-die components that have significantly less installation space claim as the same components in standard housings for example T0220. Since the entire module is provided with a housing, it makes sense to avoid costly double packaging of the components.

g) Housing made of low-pressure epoxy molding compound

The execution of the entire module housing in the form of a housing manufactured in the transfer moküng process is advantageous since the environmentally compatible so-called green compounds low-pressure epoxy materials used for this process are suitable for filling the gaps in the sandwich without bubbles and the electrical components, in particular the bare -The components from environmental influences

(e.g. liquids, dust). Furthermore, due to their physical properties, the plastics are well suited to compensate for the thermomechanical mismatch of the components used. This also involves the mechanical stabilization of the sandwich structure. In terms of the multifunctional use of the materials and components used in the module structure, the housing can also represent storage points for external connections (e.g. plug pins or spring clips for carbon brushes) and components, as well as mounting points of the module in the application. For the integration of the module into the application, the housing can advantageously be shaped in such a way that geometric boundary conditions result from the installation space and functional requirements (for example distance from Hall sensors in the module)

Ring magnet in the application) resulting in the application can be taken into account. In contrast to the standard TO220 housing, since the entire module, i.e. the logic and power section, is completely encased and is therefore electrically insulated, unlike standard housings (TO220), additional electrically insulating elements such as foils can be dispensed with during assembly are saved, which saves both the cost of the insulation material and the cost of its assembly

h) Parallelized Manufacturing Processes In the state of the art manufacturing processes the

Power components connected by means of bond connections, that is, a sequential manufacturing process. To reduce manufacturing costs, it is advantageous to replace sequential processes with parallel processes. For the power section in particular, this can be achieved by parallel soldering or gluing of the power components respectively. In the case of the module, for example, the transistors are first placed on a first substrate (lead frame) and then a second substrate (logic substrate) is placed on the transistors. With the assembly of the second substrate and the subsequent soldering or gluing process, both the wiring of the power components and the connection process of all electrical contacts of the power components and of the first and second substrates take place in parallel. The prerequisite for this type of assembly is that the power components have a solderable or adhesive surface on both sides. For this reason, for example in the case of power transistors, the gate and source connections are provided with a so-called UBM (under-bump metalization) and, in the case of contacting by means of soldering, additionally provided with solder deposits, so-called bumps. This technique of double-sided soldering aims to solder power transistors between two DBC (Direct-Bonded-Copper) substrates. Parallelization on the logic substrate can be achieved for active components by using flip-chip technology instead of bond technology, which may furthermore reduce the substrate area required, which has an advantageous effect on the module size and the space required in the application. The assembly in flip chip technology can take place both in the form of a soldering or adhesive flip chip, but preferably as an adhesive connection, since this process can be integrated more easily into the standard assembly of the substrate.

i) Mechanical stabilization module

Depending on the application and installation (forces on connector pins or connector collar) the

Electronics, an additional stabilization of the module can be advantageous. This can be implemented in different embodiments, two of which are described in more detail below.

In principle, the module can be overmolded a second time with another plastic, which is characterized by different mechanical properties compared to the low-pressure epoxy molding compound. The alternative of overmolding is particularly advantageous when the process of overmolding plastic is required for the application anyway, for example when producing a housing cover, and the overmolding of the module can be integrated into this process. In this case, no additional processes and tools are required that cause additional costs would. The module can be encapsulated both partially and completely. If no further overmolding process is provided or the overmolding of the module for technical reasons, for example, would lead to a high complexity of the spraying process leading to an increase in costs due to losses in yield, it is advantageous for the mechanical stabilization and the implementation of additional functions, for example plug collars or assembly elements for fixing the module in the Implementation in a separate module carrier. This part can be designed in such a way that it can be produced inexpensively and the module can then also be easily installed in this part, for example by means of a clip connection. Because of this

Procedure, the costs arising from the additional part and the additional processes can be minimized.

j) Separately testable unit By integrating all electrical and mechanical functions for controlling and contacting the motor in the module, the module represents an independently testable unit. This is particularly advantageous in the production flow of the application, since in this case no further assembly processes on the Module are required, which could damage the module. This means that no further cost-intensive intermediate tests are required as part of the production of the application

Production of the application can be completed with a functional test.

k) forms of completion

Due to the possibility of flexible design of the lead frame, requirements from the application regarding the mechanical and electrical interfaces, for example the position of the connector pins or the design of the spring clip, can be taken into account. This is particularly advantageous in the area of power connections if the motor is not contacted by means of the spring clips produced from the lead frame, but by additional components that take over the function of the spring clip and the brushes. The connection of the spring bracket with the

The module can be connected via riveted or welded connections, for example.

1) Noise reduction The integration of the brushes for motor contacting in the module is advantageous with regard to the noise development of the motor, since the vibrations of the spring clips are not introduced into the motor housing, which acts as a resonance chamber, as in the state-of-the-art electronics. The vibrations can be decoupled by the design of the module or the module housing and the receptacles of the module in the motor housing.

m) Extension of modular system

In principle, the approaches shown can also be transferred to high-current modules, in particular the substitution of the so-called DBC cover substrate by a

Logic substrate. The use of a logic substrate, preferably that described under c), is advantageous since it enables the control electronics to be integrated for the power section. The combination of different technologies for the production of the electronic unit according to the invention, such as the preferred use of the substrate described under c), the use of sandwich technology, which requires prebottled power components, and the direct integration of the electronics into the motor, which has a corresponding interface, is particularly advantageous -Rnow-how between motor and electronics, especially in the case of the module with brush springs. Electronics that are implemented in the form of modules, that is, with their own

Providing housings and being electrically easy to contact allows, in principle, easier external marketing than electronics based on ceramic substrates that correspond to the state of the art. Through the multifunctional use of components - e.g. the lead frame - the number of joining process steps can be reduced, which at the same time eliminates potential failure points in use, which means that better quality with regard to shaking stress can be expected.

The description of the invention is explained below by way of example with the aid of a module in sandwich technology consisting of a power and logic part for controlling an electric motor. The power section contains an H-bridge consisting of power transistors and the logic section a microprocessor with its external shading and sensors. Furthermore, for example, a lead frame is used as the first substrate and a hybrid ceramic is used as the second substrate. However, the basic principles as well as the core and advantages of the invention are scalable and Adaptation of the design to any circuit topologies of the power section and functions of the logic section can be transferred.

The assembly of the logic substrate precedes the actual structure of the module. The logic substrate is populated as a large card, onto which conductive adhesive is first applied using screen or stencil printing. Then the

Equipping the large card with the active and passive components; for passive components using standard SMD technology and for active components using standard die attach (rear side on the first substrate). After the conductive adhesive has hardened in a furnace process, the active components are bonded. In principle, it is also possible to populate the active components using flip-chip technology. Finally, this is done

Separating the large card into individual substrates that are processed in the further module structure.

The assembly of the module begins with the lead frame. When assembling the module, the solder preforms, the pre-soldered power transistors and the pre-assembled one after the other in a joining device (soldering mold) one after the other

Logic substrate (single substrate) stacked. The entire stack is then joined in a soldering step using lead-free solder, for example SnAgCu. In principle, the use of solder paste or other joining methods, for example gluing, is also conceivable. The arrangement of the joints is to be chosen in such a way that the structure is as symmetrical as possible, so that the joining process does not cause the transistors and the substrate to tilt, which can lead to short circuits in the chip area or generally to unevenly thick joints, which on the one hand reduce the yield manufacturing and on the other hand reduce the reliability of the module. Since the leadframe is used to cool the transistors, the transistors are preferably soldered to the leadframe on the drain side in order to achieve an optimum

To ensure heat dissipation of the transistors.

The elements provided in the lead frame for fastening the module in the application - for example bores - can be used in the manufacturing process to hold or to fix the lead frame in the joining device. After soldering, the component is encapsulated using transfer molding

Process in which the component is encapsulated with plastic in the cavity of a mold, which creates the housing of the module. The molding tool consists of an upper and lower part, which are closed after the component has been inserted and seal the cavity on the lead frame, in particular the so-called dam bar. Then the actual spraying process takes place, which is carried out at elevated temperature and high pressure. As soon as the plastic is cross-linked in the tool, the mold is opened and the component is ejected or removed. Depending on the plastic used and packaging requirements, post-curing as a so-called PMC (post-mold-cure) is optionally possible in one oven step.

Until after molding, the individual functional elements or areas of the lead frame are connected to one another by means of the dam bar, as a result of which the lead frame can be handled as part of the assembly process. This connection means that all electrical contacts are short-circuited, that is to say, in order to produce the electrical function, these connection points are separated, for example by a stamping process. If necessary, a bending process can be combined with the punching process for the application-specific design of the electrical and mechanical interfaces for the application. Depending on the embodiment of the module, the module is equipped with wired components as part of the final assembly, if necessary, separate carbon brackets are installed and the carbon brushes are connected to the carbon brackets. If carbon brushes with strands are used, the strand must also be connected to the corresponding connections on the module. The final assembly is completed with the electrical test, the unit that can be fully tested at this time.

Depending on the application, the module can be installed in the drive unit in different ways, but a special orientation may be required when integrating sensors, e.g. that the logic part points in the direction of the motor axis if, for example, Hall sensors have to be positioned above a pole wheel. In this case, the positioning of the sensors within the module and the

Coordinate the positioning of the module in the application. In particular, the distance requirements, for example in the case of Hall sensors, can result in the housing in the area of the sensors having contours which allow the required distances to be maintained and at the same time to install components of greater thickness compared to the Hall sensors.

In the simplest case, the module is installed directly in the application without any further measures, for example by screwing or pressing. But it is also conceivable that the module, for example, only in part of the housing of the application is inserted and fixed by mounting the cover of the application by clamping.

In other cases, it may be necessary for the module to be provided with further functional elements which, due to the mechanical properties of the low-pressure epoxy molding compound, cannot be implemented with the latter, for example plug collars. For this purpose, the module can be partially or completely extrusion-coated with a suitable plastic in an additional step prior to assembly in the application, which is preferably integrated into an anyway necessary process, for example the manufacture of a housing cover. In this case, the module is installed together with the housing cover. Alternatively, the module can first be mounted on a separately manufactured carrier, which creates an assembly with an extended function that is installed as part of the manufacturing process of the application. If the functional scope of the module is expanded, it may be advantageous to introduce an additional intermediate check before final assembly in the application.

In further embodiments of the module, a spring element can be produced from one of the external connections, which takes over the contacting of a shielding plate, the shielding plate being part of the motor housing. The shielding plate serves to shield the brush fire arising on the commutator. The contacting of the baffle plate is preferably carried out when the module is being assembled, and thus on others

Joining processes can be dispensed with.

drawings

Various exemplary embodiments of an inventive device are shown in the drawings

Electric motor shown with a control unit and explained in more detail in the following description. Show it

Figure 1 is a perspective view of an electric motor according to the invention with the open

Casing,

FIG. 2 shows a schematic section through an electronic unit, FIG. 3 shows the schematic floor plan of the control unit,

FIGS. 4 and 5 the top and side views through a further exemplary embodiment of a control unit,

FIGS. 6 and 7 a further exemplary embodiment with a shielding element as shown in FIGS. 4 and 5, and

FIGS. 8 and 9 show a further variation of an electronics unit as shown in FIGS. 4 and 5.

description

FIG. 1 shows a transmission drive unit 11 in which an electric motor 10 with an armature shaft 12 is mounted in a first housing part 14 over its entire length. A first gear element 16 is mounted on the armature shaft 12 and is coupled to a second gear element 18 of a separate worm shaft 20. The worm shaft 20 meshes with a worm wheel 22, which transmits the drive torque via a damping device 24 to an output pinion 26, which drives a window pane or a sunroof in a motor vehicle, for example. A rotor 28 is arranged on the armature shaft 12 and can be freely rotated within a stator 30 fixed to the housing. The stator 30 has permanent magnets 32 which are connected to one another by means of a two-part magnetic yoke element 34. to

Power supply to the armature shaft 12 has a commutator 36 which is in frictional connection with carbon brushes 38 which are connected to an electronics module 70 via spring clips 40. The electronics module 70 has a conductive lead frame 44, the free ends of which protrude as extensions 97 from an injection-molded plastic body 95 and form the spring clips 40, as well as electrical connections 46 for the housing connector 48 and electrical and mechanical contacting to a shielding plate 104 (not shown). The spring clips 40 are made as sheet springs 52 from copper sheet, in one piece with the lead frame 44. The spring clips 40 extend from the lead frame 44 tangentially to the collector 36 and have receptacles 54 into which the carbon brushes 38 are firmly inserted. The electronics module 70 has in addition to the Lead frame 44, 71 on a second substrate 72 on various electronic components 56, such as a microprocessor 58 or a position detection sensor 60, which interacts with a position transmitter 62 on the armature shaft 12. In order to visibly display the collector 36 and the position transmitter 62 designed as a ring magnet 64, the electronics module 70 is shown in FIG. 1 with an opening.

The electrically conductive lead frame 44 with the integrated spring clips 40 is mounted radially to the armature shaft 12 in the first housing part 14 after the gear components 16, 18, as well as the armature shaft 12 and the stator 30 have been mounted radially in the housing part 14. A cover, not shown, which closes the first housing part 14 is then mounted radially as the second housing part.

FIG. 2 shows the schematic structure of an electronic unit 70 embodied as an electronic module 70 in sandwich technology. A stamped grid 44 is formed as a first lower substrate 71, for example from a copper sheet by means of stamping, bending and stamping with different segments 73. As

Power components 75 are electrically connected to the lead frame 44 diodes 69 or transistors 77, for example power MOSFETs 79. A ceramic substrate 81 with a metallic coating 83, 84 on both sides, which are designed here as conductor tracks 78 made of silver, is arranged as a second upper substrate 72 above the power components 75. The power components 75 have at their lower

Surface 85 and upper surface 86 electrically conductive contact surfaces 87 (z. B. by means of solder bumps 90), with which they are each conductively connected to the two substrates 71, 72. The power components 75 are designed as so-called bare die elements 89, without a plastic housing, in order to enable a compact layer structure. On the coating 84 of the second facing away from the lead frame 44

Further electronic components 56, such as a microprocessor 58, a position sensor 60 and SMD components 59, are arranged on the substrate 72, which together form the logic part 57 for controlling the electric motor 10. The second substrate 72 is connected to the first substrate 71 by means of soldering or by means of a conductive adhesive, in an alternative embodiment on the lead frame 44

Holding elements 91 are formed, by means of which the power components 75 and / or the second substrate 72 are electrically contacted and mechanically fixed on the first substrate 71. FIG. 3 shows the plan view of the lead frame 44, the individual segments 73 being connected to one another by means of a dam bar 93 in such a way that the lead frame 44 can be connected as a coherent part to the second substrate 72 and then encapsulated with a plastic body 95. During the spraying process, plastic molding compound also runs in gaps 113 and cavities 113 between the two substrates

71, 72 and the power components 75. The plastic body 95 is dimensioned such that after it has been molded on, the dam bar 93 can be removed by means of punching, so that the individual segments 73 are no longer conductively connected to one another. Various extensions 97 of the lead frame 44 protrude from the plastic body 95 and form electrical and mechanical interfaces 98 with further motor components 99. Some of the extensions 97 are designed as plug pins 88 for the current and signal connection, other extensions 97 have a receptacle 100 for connecting elements 102 with which the electronics unit 70 can be fixed on the motor housing 14. Other extensions 97 are designed as electrical contact points 101 for external electrical components or for carbon strands 76. Two further extensions 97 are designed as spring clips 40, on which the carbon brushes 38 are arranged, which cooperate with the collector 36 of the armature shaft 12, as shown in FIG. 9. The spring clips 40 are bent, for example, when the dam bar 93 is cut off in such a way that the carbon brushes 38 arranged thereon bear against the collector 36 under tension after the electronics unit 70 has been installed. Another extension 97 is designed as an electrical and mechanical connecting link 103 to a shielding element 104 against electromagnetic interference. The power components 75 or other electronic components, not shown here, are arranged on the individual segments 73 in the interior of the plastic body 95.

FIG. 4 shows a plan view of the plastic body 95, which completely encloses the electronic components 56, the power components 75 and the second substrate 72 (as a molded housing 95). The extensions 97 protrude from the plastic body 95 as electrical and mechanical interfaces 98 for the motor components 99. Instead of the spring clips 40 formed in one piece with the extensions 97, separate spring clips 40, for example made of spring steel, are mechanically connected to the extensions 97, for example soldered, welded or pressed. The spring clips 40 serve not only for the mechanical, resilient mounting of the carbon brushes 38, but also for their current supply. In an alternative embodiment, along the spring clip 40 In addition, carbon strands 76 are arranged, which electrically connect the carbon brushes 38 directly to an extension 97 designed as a contact point 101 for supplying power to the carbon brushes 38 (shown in dashed lines on the upright side). Other contact points 101 form an interface 98 to additional external electrical components 74, such as a capacitor 80 designed as an electrolytic capacitor (ELKO) 80.

FIG. 5 shows a corresponding section through the electronics unit 70, the spring clips 40 extending essentially perpendicular to the plane of the first substrate 71.

In FIGS. 6 and 7, the electronics unit 70 shows that mounted on the armature shaft 12

Condition in the motor housing 14, not shown. The plastic body 95 with the spring clips 40 receiving the carbon brushes 38 is pushed radially to the armature shaft 12 over the collector 36 until the carbon brushes 38 bear against the collector 36 under prestress. The electronics unit 70 is then fixed to the housing 14 by means of the extensions 97 which are designed as fastening elements 100 and which, for example, interact with the connecting means 102. In the area of the brush fire, a shielding plate 104 for shielding against electromagnetic interference is arranged around the collector 36 and the electronics unit 70. For this purpose, the extension 97 designed as a connecting member 103 is designed, for example, as a spring element 105, which is connected to the shielding element 104 when the electronics unit 70 is assembled. In a variation of the design, further housing parts 14 made of metal, such as a pole pot as shielding elements 104, can be contacted with the connecting member 103, or the shielding bodies 104 - like the spring clips 40 or cooling surfaces 96 - can also be formed in one piece with the extensions 97 of the lead frame 44 his. By a mimimal distance between that cast in the plastic body 95

To achieve position sensor 60 and the position sensor 62 arranged on the armature shaft 12 - for example a magnetic ring - the plastic body 95 is arranged radially directly opposite the position sensor 62 at a short distance. In the exemplary embodiment, the plastic body 95 has a recess 107 in which the rotating magnetic ring 62 engages, as a result of which the overall height of the

Electric motor 10 is reduced.

In a further exemplary embodiment according to FIGS. 8 and 9, the plastic body 95 is extrusion-coated with a further plastic part 109, which is used here as a plug collar 111 for the Connector pins 88 is formed. In this case, further receptacles 100 for connecting means 102 are formed in the outer circumference of the plug collar 111 as fastening elements 100, in which plug 111 and thus the electronics unit 70 can be fixed in the housing part 14.

It should be noted that with regard to the exemplary embodiments shown in all the figures, a wide range of possible combinations of the individual features with one another are possible. The selection of the individual motor components 99, the external electrical components 74 or the electronic components 56 of the electronics unit 70 can thus be adapted to the corresponding application. Instead of the extensions 97 designed as interfaces 98, they can also be formed in one piece with the corresponding motor components 99 or the external electrical components 74. The production of the conductive lead frame 44 is also not limited to punching, for example, but can be produced using any method that provides a conductive circuit carrier 44. Preferably, the invention

Device Use with electric adjustment drives, especially window panes and sunroofs. However, the electronic module 70 according to the invention is not limited to the use of a brush motor, but can also be used for EC motors and other actuators, for example for valve controls.

Claims

Expectations

1. Electric motor (10), in particular for adjusting moving parts in the motor vehicle, with an electronic unit (70) in sandwich construction, which has a first electrically conductive substrate (71) and a second electrically conductive substrate (72), between which power components ( 75) and are electrically connected to both substrates (71, 72), and the second substrate (72) is equipped with further electronic components (56) on a side (84) facing away from the first substrate (71), the first substrate (71) is designed as a lead frame (44) which, together with the second substrate (72), is extrusion-coated with a plastic body (95) such that extensions (97) of the lead frame (44) protrude from the plastic body (95) form an electrical and / or mechanical interface (98) for connecting further motor components (99, 38, 40, 104, 102, 80).

2. Electric motor (10) according to claim 1, characterized in that the extensions (97) as fastening elements (100) of the electronics unit (70) - in particular as bores (100) - are formed.

3. Electric motor (10) according to one of claims 1 or 2, characterized in that the extensions (97) as Steckeφins (88), or contact points (101) to external electrical

Components (74), such as a capacitor (80) or an inductor or a strand (76), are made, and in particular are made of copper-containing material.

4. Electric motor (10) according to one of the preceding claims, characterized in that the motor components (99) spring clip (40) for receiving

Carbon brushes (38) are.

5. Electric motor (10) according to one of the preceding claims, characterized in that the motor components (99) are electromagnetic shielding bodies (104) which are in particular formed in one piece with the extensions (97).

6. Electric motor (10) according to one of the preceding claims, characterized in that on the lead frame (44) holding elements (91) are formed, in which the Power components (95) and / or the second substrate (72) can be inserted in order to establish an electrical and / or mechanical connection to the lead frame (44).

7. Electric motor (10) according to one of the preceding claims, characterized in that the contact points (101) as interfaces (98) in insulation displacement.

Technology are trained.

8. Electric motor (10) according to one of the preceding claims, characterized in that on the second substrate (72) as electronic components (56) a microprocessor (58) and / or a control logic (58) and a position sensor system

(60) for an armature shaft (12) of the electric motor (10) are arranged.

9. Electric motor (10) according to one of the preceding claims, characterized in that the second substrate (72) has at least one electrically conductive surface (83, 84), and the electronic components (56) are variable by means of

Soldering or conductive gluing - especially using flip-chip technology - can be equipped.

10. Electric motor (10) according to one of the preceding claims, characterized in that the second substrate (72) has a ceramic plate (81) and on its top and bottom in each case at least one interconnect level (83, 84) which - in particular by means of vias- Holes - electrically connected.

11. Electric motor (10) according to one of the preceding claims, characterized in that the power components (75) and / or the components (56) are designed as bare die elements without a housing.

12. Electric motor (10) according to any one of the preceding claims, characterized in that the power components (75) have a surface (85, 86) that can be soldered or conductively glued on both sides, which is particularly for the soldering technique on the side facing the second substrate (72) (86) is provided with solder bumps (90).

13. Electric motor (10) according to one of the preceding claims, characterized in that the power components (75) are designed as power MOSFETS (79).

14. Electric motor (10) according to one of the preceding claims, characterized in that the power components (75) for better heat dissipation on the first substrate (71) are arranged symmetrically.

15. Electric motor (10) according to one of the preceding claims, characterized in that the two substrates (71, 72) are designed as a cooling body, in particular at least one extension (97) of the lead frame (44) as a cooling surface (96) outside the plastic body (95) is formed.

16. Electric motor (10) according to any one of the preceding claims, characterized in that the plastic body (95) is formed by means of a transfer molding method, in particular epoxy molding compound in a gap (113) between the two substrates (71, 72 ) flows.

17. Electric motor (10) according to one of the preceding claims, characterized in that the plastic body (95) is extrusion-coated with a further plastic of a housing part (14) and / or a plug collar (111).

18. Electric motor (10) according to one of the preceding claims, characterized in that the plastic body (95) is arranged on a separate module carrier, and in particular is fixed by means of a clip connection.

19. Electric motor (10) according to one of the preceding claims, characterized in that the electronics unit (70) can be mounted radially to the armature shaft (12) and directly opposite a commutator (36) and / or a position transmitter (62, 64) of the armature shaft (12 ) is arranged, and the plastic body (95) in particular has a shape (107) to adapt to the engine geometry.

20. Electronic module (70) in sandwich construction, in particular according to one of the preceding claims, which has a first electrically conductive substrate (71) and a second electrically conductive substrate (72), between which power components (75) are arranged and with both substrates (71, 72) are electrically connected, and the second substrate (72) on one of the first substrate (71) opposite side (84) is equipped with further electronic components (56), the first substrate (71) being in the form of a lead frame (44) which, together with the second substrate (72), is extrusion-coated with a plastic body (95), that extensions (97) of the lead frame (44) protrude from the plastic body (95), which form an electrical and mechanical interface (98) for connecting further motor components (99, 38, 40, 104, 102, 80).

21. A method for producing an electric motor (10) with an electronic control unit (70), characterized by the following steps: - a one-piece conductive lead frame (71, 44) is punched out, a dam bar (93) separating the individual segments (73) Pre-soldered power components (75) and a ceramic substrate (72, 81) with other components (56) are layered together on the lead frame (44) to form a sandwich - the individual layers (71 , 75, 72) electrically connected to one another by means of transfer molding processes, a module body (95) made of plastic is injection molded around the sandwich (70) in such a way that the dam bar (93) is arranged outside the module body (95) - the dam -Bar (93) is separated and the extensions (97) of the lead frame (44) protruding from the module body (95) are mechanically connected to motor components (99) - such as carbon brushes (38) or electromagnetic shielding elements duck (104) or connecting means (102) - or connected to external electrical components (74).

22. The method according to claim 20, characterized in that a magnetic position sensor (60) is arranged on the ceramic substrate (72) and molded with plastic (95) such that the position sensor (60) after the assembly of the control unit (70) is arranged directly opposite a magnetic position transmitter (62, 64) arranged on an armature shaft (12) of the electric motor (10) and interacts with it.